8068 lines
241 KiB
C
8068 lines
241 KiB
C
/* Common subexpression elimination for GNU compiler.
|
||
Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998
|
||
1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
|
||
|
||
This file is part of GCC.
|
||
|
||
GCC is free software; you can redistribute it and/or modify it under
|
||
the terms of the GNU General Public License as published by the Free
|
||
Software Foundation; either version 2, or (at your option) any later
|
||
version.
|
||
|
||
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
|
||
WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
||
for more details.
|
||
|
||
You should have received a copy of the GNU General Public License
|
||
along with GCC; see the file COPYING. If not, write to the Free
|
||
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
|
||
02110-1301, USA. */
|
||
|
||
#include "config.h"
|
||
/* stdio.h must precede rtl.h for FFS. */
|
||
#include "system.h"
|
||
#include "coretypes.h"
|
||
#include "tm.h"
|
||
#include "rtl.h"
|
||
#include "tm_p.h"
|
||
#include "hard-reg-set.h"
|
||
#include "regs.h"
|
||
#include "basic-block.h"
|
||
#include "flags.h"
|
||
#include "real.h"
|
||
#include "insn-config.h"
|
||
#include "recog.h"
|
||
#include "function.h"
|
||
#include "expr.h"
|
||
#include "toplev.h"
|
||
#include "output.h"
|
||
#include "ggc.h"
|
||
#include "timevar.h"
|
||
#include "except.h"
|
||
#include "target.h"
|
||
#include "params.h"
|
||
#include "rtlhooks-def.h"
|
||
#include "tree-pass.h"
|
||
|
||
/* The basic idea of common subexpression elimination is to go
|
||
through the code, keeping a record of expressions that would
|
||
have the same value at the current scan point, and replacing
|
||
expressions encountered with the cheapest equivalent expression.
|
||
|
||
It is too complicated to keep track of the different possibilities
|
||
when control paths merge in this code; so, at each label, we forget all
|
||
that is known and start fresh. This can be described as processing each
|
||
extended basic block separately. We have a separate pass to perform
|
||
global CSE.
|
||
|
||
Note CSE can turn a conditional or computed jump into a nop or
|
||
an unconditional jump. When this occurs we arrange to run the jump
|
||
optimizer after CSE to delete the unreachable code.
|
||
|
||
We use two data structures to record the equivalent expressions:
|
||
a hash table for most expressions, and a vector of "quantity
|
||
numbers" to record equivalent (pseudo) registers.
|
||
|
||
The use of the special data structure for registers is desirable
|
||
because it is faster. It is possible because registers references
|
||
contain a fairly small number, the register number, taken from
|
||
a contiguously allocated series, and two register references are
|
||
identical if they have the same number. General expressions
|
||
do not have any such thing, so the only way to retrieve the
|
||
information recorded on an expression other than a register
|
||
is to keep it in a hash table.
|
||
|
||
Registers and "quantity numbers":
|
||
|
||
At the start of each basic block, all of the (hardware and pseudo)
|
||
registers used in the function are given distinct quantity
|
||
numbers to indicate their contents. During scan, when the code
|
||
copies one register into another, we copy the quantity number.
|
||
When a register is loaded in any other way, we allocate a new
|
||
quantity number to describe the value generated by this operation.
|
||
`REG_QTY (N)' records what quantity register N is currently thought
|
||
of as containing.
|
||
|
||
All real quantity numbers are greater than or equal to zero.
|
||
If register N has not been assigned a quantity, `REG_QTY (N)' will
|
||
equal -N - 1, which is always negative.
|
||
|
||
Quantity numbers below zero do not exist and none of the `qty_table'
|
||
entries should be referenced with a negative index.
|
||
|
||
We also maintain a bidirectional chain of registers for each
|
||
quantity number. The `qty_table` members `first_reg' and `last_reg',
|
||
and `reg_eqv_table' members `next' and `prev' hold these chains.
|
||
|
||
The first register in a chain is the one whose lifespan is least local.
|
||
Among equals, it is the one that was seen first.
|
||
We replace any equivalent register with that one.
|
||
|
||
If two registers have the same quantity number, it must be true that
|
||
REG expressions with qty_table `mode' must be in the hash table for both
|
||
registers and must be in the same class.
|
||
|
||
The converse is not true. Since hard registers may be referenced in
|
||
any mode, two REG expressions might be equivalent in the hash table
|
||
but not have the same quantity number if the quantity number of one
|
||
of the registers is not the same mode as those expressions.
|
||
|
||
Constants and quantity numbers
|
||
|
||
When a quantity has a known constant value, that value is stored
|
||
in the appropriate qty_table `const_rtx'. This is in addition to
|
||
putting the constant in the hash table as is usual for non-regs.
|
||
|
||
Whether a reg or a constant is preferred is determined by the configuration
|
||
macro CONST_COSTS and will often depend on the constant value. In any
|
||
event, expressions containing constants can be simplified, by fold_rtx.
|
||
|
||
When a quantity has a known nearly constant value (such as an address
|
||
of a stack slot), that value is stored in the appropriate qty_table
|
||
`const_rtx'.
|
||
|
||
Integer constants don't have a machine mode. However, cse
|
||
determines the intended machine mode from the destination
|
||
of the instruction that moves the constant. The machine mode
|
||
is recorded in the hash table along with the actual RTL
|
||
constant expression so that different modes are kept separate.
|
||
|
||
Other expressions:
|
||
|
||
To record known equivalences among expressions in general
|
||
we use a hash table called `table'. It has a fixed number of buckets
|
||
that contain chains of `struct table_elt' elements for expressions.
|
||
These chains connect the elements whose expressions have the same
|
||
hash codes.
|
||
|
||
Other chains through the same elements connect the elements which
|
||
currently have equivalent values.
|
||
|
||
Register references in an expression are canonicalized before hashing
|
||
the expression. This is done using `reg_qty' and qty_table `first_reg'.
|
||
The hash code of a register reference is computed using the quantity
|
||
number, not the register number.
|
||
|
||
When the value of an expression changes, it is necessary to remove from the
|
||
hash table not just that expression but all expressions whose values
|
||
could be different as a result.
|
||
|
||
1. If the value changing is in memory, except in special cases
|
||
ANYTHING referring to memory could be changed. That is because
|
||
nobody knows where a pointer does not point.
|
||
The function `invalidate_memory' removes what is necessary.
|
||
|
||
The special cases are when the address is constant or is
|
||
a constant plus a fixed register such as the frame pointer
|
||
or a static chain pointer. When such addresses are stored in,
|
||
we can tell exactly which other such addresses must be invalidated
|
||
due to overlap. `invalidate' does this.
|
||
All expressions that refer to non-constant
|
||
memory addresses are also invalidated. `invalidate_memory' does this.
|
||
|
||
2. If the value changing is a register, all expressions
|
||
containing references to that register, and only those,
|
||
must be removed.
|
||
|
||
Because searching the entire hash table for expressions that contain
|
||
a register is very slow, we try to figure out when it isn't necessary.
|
||
Precisely, this is necessary only when expressions have been
|
||
entered in the hash table using this register, and then the value has
|
||
changed, and then another expression wants to be added to refer to
|
||
the register's new value. This sequence of circumstances is rare
|
||
within any one basic block.
|
||
|
||
`REG_TICK' and `REG_IN_TABLE', accessors for members of
|
||
cse_reg_info, are used to detect this case. REG_TICK (i) is
|
||
incremented whenever a value is stored in register i.
|
||
REG_IN_TABLE (i) holds -1 if no references to register i have been
|
||
entered in the table; otherwise, it contains the value REG_TICK (i)
|
||
had when the references were entered. If we want to enter a
|
||
reference and REG_IN_TABLE (i) != REG_TICK (i), we must scan and
|
||
remove old references. Until we want to enter a new entry, the
|
||
mere fact that the two vectors don't match makes the entries be
|
||
ignored if anyone tries to match them.
|
||
|
||
Registers themselves are entered in the hash table as well as in
|
||
the equivalent-register chains. However, `REG_TICK' and
|
||
`REG_IN_TABLE' do not apply to expressions which are simple
|
||
register references. These expressions are removed from the table
|
||
immediately when they become invalid, and this can be done even if
|
||
we do not immediately search for all the expressions that refer to
|
||
the register.
|
||
|
||
A CLOBBER rtx in an instruction invalidates its operand for further
|
||
reuse. A CLOBBER or SET rtx whose operand is a MEM:BLK
|
||
invalidates everything that resides in memory.
|
||
|
||
Related expressions:
|
||
|
||
Constant expressions that differ only by an additive integer
|
||
are called related. When a constant expression is put in
|
||
the table, the related expression with no constant term
|
||
is also entered. These are made to point at each other
|
||
so that it is possible to find out if there exists any
|
||
register equivalent to an expression related to a given expression. */
|
||
|
||
/* Length of qty_table vector. We know in advance we will not need
|
||
a quantity number this big. */
|
||
|
||
static int max_qty;
|
||
|
||
/* Next quantity number to be allocated.
|
||
This is 1 + the largest number needed so far. */
|
||
|
||
static int next_qty;
|
||
|
||
/* Per-qty information tracking.
|
||
|
||
`first_reg' and `last_reg' track the head and tail of the
|
||
chain of registers which currently contain this quantity.
|
||
|
||
`mode' contains the machine mode of this quantity.
|
||
|
||
`const_rtx' holds the rtx of the constant value of this
|
||
quantity, if known. A summations of the frame/arg pointer
|
||
and a constant can also be entered here. When this holds
|
||
a known value, `const_insn' is the insn which stored the
|
||
constant value.
|
||
|
||
`comparison_{code,const,qty}' are used to track when a
|
||
comparison between a quantity and some constant or register has
|
||
been passed. In such a case, we know the results of the comparison
|
||
in case we see it again. These members record a comparison that
|
||
is known to be true. `comparison_code' holds the rtx code of such
|
||
a comparison, else it is set to UNKNOWN and the other two
|
||
comparison members are undefined. `comparison_const' holds
|
||
the constant being compared against, or zero if the comparison
|
||
is not against a constant. `comparison_qty' holds the quantity
|
||
being compared against when the result is known. If the comparison
|
||
is not with a register, `comparison_qty' is -1. */
|
||
|
||
struct qty_table_elem
|
||
{
|
||
rtx const_rtx;
|
||
rtx const_insn;
|
||
rtx comparison_const;
|
||
int comparison_qty;
|
||
unsigned int first_reg, last_reg;
|
||
/* The sizes of these fields should match the sizes of the
|
||
code and mode fields of struct rtx_def (see rtl.h). */
|
||
ENUM_BITFIELD(rtx_code) comparison_code : 16;
|
||
ENUM_BITFIELD(machine_mode) mode : 8;
|
||
};
|
||
|
||
/* The table of all qtys, indexed by qty number. */
|
||
static struct qty_table_elem *qty_table;
|
||
|
||
/* Structure used to pass arguments via for_each_rtx to function
|
||
cse_change_cc_mode. */
|
||
struct change_cc_mode_args
|
||
{
|
||
rtx insn;
|
||
rtx newreg;
|
||
};
|
||
|
||
#ifdef HAVE_cc0
|
||
/* For machines that have a CC0, we do not record its value in the hash
|
||
table since its use is guaranteed to be the insn immediately following
|
||
its definition and any other insn is presumed to invalidate it.
|
||
|
||
Instead, we store below the value last assigned to CC0. If it should
|
||
happen to be a constant, it is stored in preference to the actual
|
||
assigned value. In case it is a constant, we store the mode in which
|
||
the constant should be interpreted. */
|
||
|
||
static rtx prev_insn_cc0;
|
||
static enum machine_mode prev_insn_cc0_mode;
|
||
|
||
/* Previous actual insn. 0 if at first insn of basic block. */
|
||
|
||
static rtx prev_insn;
|
||
#endif
|
||
|
||
/* Insn being scanned. */
|
||
|
||
static rtx this_insn;
|
||
|
||
/* Index by register number, gives the number of the next (or
|
||
previous) register in the chain of registers sharing the same
|
||
value.
|
||
|
||
Or -1 if this register is at the end of the chain.
|
||
|
||
If REG_QTY (N) == -N - 1, reg_eqv_table[N].next is undefined. */
|
||
|
||
/* Per-register equivalence chain. */
|
||
struct reg_eqv_elem
|
||
{
|
||
int next, prev;
|
||
};
|
||
|
||
/* The table of all register equivalence chains. */
|
||
static struct reg_eqv_elem *reg_eqv_table;
|
||
|
||
struct cse_reg_info
|
||
{
|
||
/* The timestamp at which this register is initialized. */
|
||
unsigned int timestamp;
|
||
|
||
/* The quantity number of the register's current contents. */
|
||
int reg_qty;
|
||
|
||
/* The number of times the register has been altered in the current
|
||
basic block. */
|
||
int reg_tick;
|
||
|
||
/* The REG_TICK value at which rtx's containing this register are
|
||
valid in the hash table. If this does not equal the current
|
||
reg_tick value, such expressions existing in the hash table are
|
||
invalid. */
|
||
int reg_in_table;
|
||
|
||
/* The SUBREG that was set when REG_TICK was last incremented. Set
|
||
to -1 if the last store was to the whole register, not a subreg. */
|
||
unsigned int subreg_ticked;
|
||
};
|
||
|
||
/* A table of cse_reg_info indexed by register numbers. */
|
||
static struct cse_reg_info *cse_reg_info_table;
|
||
|
||
/* The size of the above table. */
|
||
static unsigned int cse_reg_info_table_size;
|
||
|
||
/* The index of the first entry that has not been initialized. */
|
||
static unsigned int cse_reg_info_table_first_uninitialized;
|
||
|
||
/* The timestamp at the beginning of the current run of
|
||
cse_basic_block. We increment this variable at the beginning of
|
||
the current run of cse_basic_block. The timestamp field of a
|
||
cse_reg_info entry matches the value of this variable if and only
|
||
if the entry has been initialized during the current run of
|
||
cse_basic_block. */
|
||
static unsigned int cse_reg_info_timestamp;
|
||
|
||
/* A HARD_REG_SET containing all the hard registers for which there is
|
||
currently a REG expression in the hash table. Note the difference
|
||
from the above variables, which indicate if the REG is mentioned in some
|
||
expression in the table. */
|
||
|
||
static HARD_REG_SET hard_regs_in_table;
|
||
|
||
/* CUID of insn that starts the basic block currently being cse-processed. */
|
||
|
||
static int cse_basic_block_start;
|
||
|
||
/* CUID of insn that ends the basic block currently being cse-processed. */
|
||
|
||
static int cse_basic_block_end;
|
||
|
||
/* Vector mapping INSN_UIDs to cuids.
|
||
The cuids are like uids but increase monotonically always.
|
||
We use them to see whether a reg is used outside a given basic block. */
|
||
|
||
static int *uid_cuid;
|
||
|
||
/* Highest UID in UID_CUID. */
|
||
static int max_uid;
|
||
|
||
/* Get the cuid of an insn. */
|
||
|
||
#define INSN_CUID(INSN) (uid_cuid[INSN_UID (INSN)])
|
||
|
||
/* Nonzero if this pass has made changes, and therefore it's
|
||
worthwhile to run the garbage collector. */
|
||
|
||
static int cse_altered;
|
||
|
||
/* Nonzero if cse has altered conditional jump insns
|
||
in such a way that jump optimization should be redone. */
|
||
|
||
static int cse_jumps_altered;
|
||
|
||
/* Nonzero if we put a LABEL_REF into the hash table for an INSN without a
|
||
REG_LABEL, we have to rerun jump after CSE to put in the note. */
|
||
static int recorded_label_ref;
|
||
|
||
/* canon_hash stores 1 in do_not_record
|
||
if it notices a reference to CC0, PC, or some other volatile
|
||
subexpression. */
|
||
|
||
static int do_not_record;
|
||
|
||
/* canon_hash stores 1 in hash_arg_in_memory
|
||
if it notices a reference to memory within the expression being hashed. */
|
||
|
||
static int hash_arg_in_memory;
|
||
|
||
/* The hash table contains buckets which are chains of `struct table_elt's,
|
||
each recording one expression's information.
|
||
That expression is in the `exp' field.
|
||
|
||
The canon_exp field contains a canonical (from the point of view of
|
||
alias analysis) version of the `exp' field.
|
||
|
||
Those elements with the same hash code are chained in both directions
|
||
through the `next_same_hash' and `prev_same_hash' fields.
|
||
|
||
Each set of expressions with equivalent values
|
||
are on a two-way chain through the `next_same_value'
|
||
and `prev_same_value' fields, and all point with
|
||
the `first_same_value' field at the first element in
|
||
that chain. The chain is in order of increasing cost.
|
||
Each element's cost value is in its `cost' field.
|
||
|
||
The `in_memory' field is nonzero for elements that
|
||
involve any reference to memory. These elements are removed
|
||
whenever a write is done to an unidentified location in memory.
|
||
To be safe, we assume that a memory address is unidentified unless
|
||
the address is either a symbol constant or a constant plus
|
||
the frame pointer or argument pointer.
|
||
|
||
The `related_value' field is used to connect related expressions
|
||
(that differ by adding an integer).
|
||
The related expressions are chained in a circular fashion.
|
||
`related_value' is zero for expressions for which this
|
||
chain is not useful.
|
||
|
||
The `cost' field stores the cost of this element's expression.
|
||
The `regcost' field stores the value returned by approx_reg_cost for
|
||
this element's expression.
|
||
|
||
The `is_const' flag is set if the element is a constant (including
|
||
a fixed address).
|
||
|
||
The `flag' field is used as a temporary during some search routines.
|
||
|
||
The `mode' field is usually the same as GET_MODE (`exp'), but
|
||
if `exp' is a CONST_INT and has no machine mode then the `mode'
|
||
field is the mode it was being used as. Each constant is
|
||
recorded separately for each mode it is used with. */
|
||
|
||
struct table_elt
|
||
{
|
||
rtx exp;
|
||
rtx canon_exp;
|
||
struct table_elt *next_same_hash;
|
||
struct table_elt *prev_same_hash;
|
||
struct table_elt *next_same_value;
|
||
struct table_elt *prev_same_value;
|
||
struct table_elt *first_same_value;
|
||
struct table_elt *related_value;
|
||
int cost;
|
||
int regcost;
|
||
/* The size of this field should match the size
|
||
of the mode field of struct rtx_def (see rtl.h). */
|
||
ENUM_BITFIELD(machine_mode) mode : 8;
|
||
char in_memory;
|
||
char is_const;
|
||
char flag;
|
||
};
|
||
|
||
/* We don't want a lot of buckets, because we rarely have very many
|
||
things stored in the hash table, and a lot of buckets slows
|
||
down a lot of loops that happen frequently. */
|
||
#define HASH_SHIFT 5
|
||
#define HASH_SIZE (1 << HASH_SHIFT)
|
||
#define HASH_MASK (HASH_SIZE - 1)
|
||
|
||
/* Compute hash code of X in mode M. Special-case case where X is a pseudo
|
||
register (hard registers may require `do_not_record' to be set). */
|
||
|
||
#define HASH(X, M) \
|
||
((REG_P (X) && REGNO (X) >= FIRST_PSEUDO_REGISTER \
|
||
? (((unsigned) REG << 7) + (unsigned) REG_QTY (REGNO (X))) \
|
||
: canon_hash (X, M)) & HASH_MASK)
|
||
|
||
/* Like HASH, but without side-effects. */
|
||
#define SAFE_HASH(X, M) \
|
||
((REG_P (X) && REGNO (X) >= FIRST_PSEUDO_REGISTER \
|
||
? (((unsigned) REG << 7) + (unsigned) REG_QTY (REGNO (X))) \
|
||
: safe_hash (X, M)) & HASH_MASK)
|
||
|
||
/* Determine whether register number N is considered a fixed register for the
|
||
purpose of approximating register costs.
|
||
It is desirable to replace other regs with fixed regs, to reduce need for
|
||
non-fixed hard regs.
|
||
A reg wins if it is either the frame pointer or designated as fixed. */
|
||
#define FIXED_REGNO_P(N) \
|
||
((N) == FRAME_POINTER_REGNUM || (N) == HARD_FRAME_POINTER_REGNUM \
|
||
|| fixed_regs[N] || global_regs[N])
|
||
|
||
/* Compute cost of X, as stored in the `cost' field of a table_elt. Fixed
|
||
hard registers and pointers into the frame are the cheapest with a cost
|
||
of 0. Next come pseudos with a cost of one and other hard registers with
|
||
a cost of 2. Aside from these special cases, call `rtx_cost'. */
|
||
|
||
#define CHEAP_REGNO(N) \
|
||
(REGNO_PTR_FRAME_P(N) \
|
||
|| (HARD_REGISTER_NUM_P (N) \
|
||
&& FIXED_REGNO_P (N) && REGNO_REG_CLASS (N) != NO_REGS))
|
||
|
||
#define COST(X) (REG_P (X) ? 0 : notreg_cost (X, SET))
|
||
#define COST_IN(X,OUTER) (REG_P (X) ? 0 : notreg_cost (X, OUTER))
|
||
|
||
/* Get the number of times this register has been updated in this
|
||
basic block. */
|
||
|
||
#define REG_TICK(N) (get_cse_reg_info (N)->reg_tick)
|
||
|
||
/* Get the point at which REG was recorded in the table. */
|
||
|
||
#define REG_IN_TABLE(N) (get_cse_reg_info (N)->reg_in_table)
|
||
|
||
/* Get the SUBREG set at the last increment to REG_TICK (-1 if not a
|
||
SUBREG). */
|
||
|
||
#define SUBREG_TICKED(N) (get_cse_reg_info (N)->subreg_ticked)
|
||
|
||
/* Get the quantity number for REG. */
|
||
|
||
#define REG_QTY(N) (get_cse_reg_info (N)->reg_qty)
|
||
|
||
/* Determine if the quantity number for register X represents a valid index
|
||
into the qty_table. */
|
||
|
||
#define REGNO_QTY_VALID_P(N) (REG_QTY (N) >= 0)
|
||
|
||
static struct table_elt *table[HASH_SIZE];
|
||
|
||
/* Number of elements in the hash table. */
|
||
|
||
static unsigned int table_size;
|
||
|
||
/* Chain of `struct table_elt's made so far for this function
|
||
but currently removed from the table. */
|
||
|
||
static struct table_elt *free_element_chain;
|
||
|
||
/* Set to the cost of a constant pool reference if one was found for a
|
||
symbolic constant. If this was found, it means we should try to
|
||
convert constants into constant pool entries if they don't fit in
|
||
the insn. */
|
||
|
||
static int constant_pool_entries_cost;
|
||
static int constant_pool_entries_regcost;
|
||
|
||
/* This data describes a block that will be processed by cse_basic_block. */
|
||
|
||
struct cse_basic_block_data
|
||
{
|
||
/* Lowest CUID value of insns in block. */
|
||
int low_cuid;
|
||
/* Highest CUID value of insns in block. */
|
||
int high_cuid;
|
||
/* Total number of SETs in block. */
|
||
int nsets;
|
||
/* Last insn in the block. */
|
||
rtx last;
|
||
/* Size of current branch path, if any. */
|
||
int path_size;
|
||
/* Current branch path, indicating which branches will be taken. */
|
||
struct branch_path
|
||
{
|
||
/* The branch insn. */
|
||
rtx branch;
|
||
/* Whether it should be taken or not. AROUND is the same as taken
|
||
except that it is used when the destination label is not preceded
|
||
by a BARRIER. */
|
||
enum taken {PATH_TAKEN, PATH_NOT_TAKEN, PATH_AROUND} status;
|
||
} *path;
|
||
};
|
||
|
||
static bool fixed_base_plus_p (rtx x);
|
||
static int notreg_cost (rtx, enum rtx_code);
|
||
static int approx_reg_cost_1 (rtx *, void *);
|
||
static int approx_reg_cost (rtx);
|
||
static int preferable (int, int, int, int);
|
||
static void new_basic_block (void);
|
||
static void make_new_qty (unsigned int, enum machine_mode);
|
||
static void make_regs_eqv (unsigned int, unsigned int);
|
||
static void delete_reg_equiv (unsigned int);
|
||
static int mention_regs (rtx);
|
||
static int insert_regs (rtx, struct table_elt *, int);
|
||
static void remove_from_table (struct table_elt *, unsigned);
|
||
static struct table_elt *lookup (rtx, unsigned, enum machine_mode);
|
||
static struct table_elt *lookup_for_remove (rtx, unsigned, enum machine_mode);
|
||
static rtx lookup_as_function (rtx, enum rtx_code);
|
||
static struct table_elt *insert (rtx, struct table_elt *, unsigned,
|
||
enum machine_mode);
|
||
static void merge_equiv_classes (struct table_elt *, struct table_elt *);
|
||
static void invalidate (rtx, enum machine_mode);
|
||
static int cse_rtx_varies_p (rtx, int);
|
||
static void remove_invalid_refs (unsigned int);
|
||
static void remove_invalid_subreg_refs (unsigned int, unsigned int,
|
||
enum machine_mode);
|
||
static void rehash_using_reg (rtx);
|
||
static void invalidate_memory (void);
|
||
static void invalidate_for_call (void);
|
||
static rtx use_related_value (rtx, struct table_elt *);
|
||
|
||
static inline unsigned canon_hash (rtx, enum machine_mode);
|
||
static inline unsigned safe_hash (rtx, enum machine_mode);
|
||
static unsigned hash_rtx_string (const char *);
|
||
|
||
static rtx canon_reg (rtx, rtx);
|
||
static void find_best_addr (rtx, rtx *, enum machine_mode);
|
||
static enum rtx_code find_comparison_args (enum rtx_code, rtx *, rtx *,
|
||
enum machine_mode *,
|
||
enum machine_mode *);
|
||
static rtx fold_rtx (rtx, rtx);
|
||
static rtx equiv_constant (rtx);
|
||
static void record_jump_equiv (rtx, int);
|
||
static void record_jump_cond (enum rtx_code, enum machine_mode, rtx, rtx,
|
||
int);
|
||
static void cse_insn (rtx, rtx);
|
||
static void cse_end_of_basic_block (rtx, struct cse_basic_block_data *,
|
||
int, int);
|
||
static int addr_affects_sp_p (rtx);
|
||
static void invalidate_from_clobbers (rtx);
|
||
static rtx cse_process_notes (rtx, rtx);
|
||
static void invalidate_skipped_set (rtx, rtx, void *);
|
||
static void invalidate_skipped_block (rtx);
|
||
static rtx cse_basic_block (rtx, rtx, struct branch_path *);
|
||
static void count_reg_usage (rtx, int *, rtx, int);
|
||
static int check_for_label_ref (rtx *, void *);
|
||
extern void dump_class (struct table_elt*);
|
||
static void get_cse_reg_info_1 (unsigned int regno);
|
||
static struct cse_reg_info * get_cse_reg_info (unsigned int regno);
|
||
static int check_dependence (rtx *, void *);
|
||
|
||
static void flush_hash_table (void);
|
||
static bool insn_live_p (rtx, int *);
|
||
static bool set_live_p (rtx, rtx, int *);
|
||
static bool dead_libcall_p (rtx, int *);
|
||
static int cse_change_cc_mode (rtx *, void *);
|
||
static void cse_change_cc_mode_insn (rtx, rtx);
|
||
static void cse_change_cc_mode_insns (rtx, rtx, rtx);
|
||
static enum machine_mode cse_cc_succs (basic_block, rtx, rtx, bool);
|
||
|
||
|
||
#undef RTL_HOOKS_GEN_LOWPART
|
||
#define RTL_HOOKS_GEN_LOWPART gen_lowpart_if_possible
|
||
|
||
static const struct rtl_hooks cse_rtl_hooks = RTL_HOOKS_INITIALIZER;
|
||
|
||
/* Nonzero if X has the form (PLUS frame-pointer integer). We check for
|
||
virtual regs here because the simplify_*_operation routines are called
|
||
by integrate.c, which is called before virtual register instantiation. */
|
||
|
||
static bool
|
||
fixed_base_plus_p (rtx x)
|
||
{
|
||
switch (GET_CODE (x))
|
||
{
|
||
case REG:
|
||
if (x == frame_pointer_rtx || x == hard_frame_pointer_rtx)
|
||
return true;
|
||
if (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM])
|
||
return true;
|
||
if (REGNO (x) >= FIRST_VIRTUAL_REGISTER
|
||
&& REGNO (x) <= LAST_VIRTUAL_REGISTER)
|
||
return true;
|
||
return false;
|
||
|
||
case PLUS:
|
||
if (GET_CODE (XEXP (x, 1)) != CONST_INT)
|
||
return false;
|
||
return fixed_base_plus_p (XEXP (x, 0));
|
||
|
||
default:
|
||
return false;
|
||
}
|
||
}
|
||
|
||
/* Dump the expressions in the equivalence class indicated by CLASSP.
|
||
This function is used only for debugging. */
|
||
void
|
||
dump_class (struct table_elt *classp)
|
||
{
|
||
struct table_elt *elt;
|
||
|
||
fprintf (stderr, "Equivalence chain for ");
|
||
print_rtl (stderr, classp->exp);
|
||
fprintf (stderr, ": \n");
|
||
|
||
for (elt = classp->first_same_value; elt; elt = elt->next_same_value)
|
||
{
|
||
print_rtl (stderr, elt->exp);
|
||
fprintf (stderr, "\n");
|
||
}
|
||
}
|
||
|
||
/* Subroutine of approx_reg_cost; called through for_each_rtx. */
|
||
|
||
static int
|
||
approx_reg_cost_1 (rtx *xp, void *data)
|
||
{
|
||
rtx x = *xp;
|
||
int *cost_p = data;
|
||
|
||
if (x && REG_P (x))
|
||
{
|
||
unsigned int regno = REGNO (x);
|
||
|
||
if (! CHEAP_REGNO (regno))
|
||
{
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
if (SMALL_REGISTER_CLASSES)
|
||
return 1;
|
||
*cost_p += 2;
|
||
}
|
||
else
|
||
*cost_p += 1;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return an estimate of the cost of the registers used in an rtx.
|
||
This is mostly the number of different REG expressions in the rtx;
|
||
however for some exceptions like fixed registers we use a cost of
|
||
0. If any other hard register reference occurs, return MAX_COST. */
|
||
|
||
static int
|
||
approx_reg_cost (rtx x)
|
||
{
|
||
int cost = 0;
|
||
|
||
if (for_each_rtx (&x, approx_reg_cost_1, (void *) &cost))
|
||
return MAX_COST;
|
||
|
||
return cost;
|
||
}
|
||
|
||
/* Returns a canonical version of X for the address, from the point of view,
|
||
that all multiplications are represented as MULT instead of the multiply
|
||
by a power of 2 being represented as ASHIFT. */
|
||
|
||
static rtx
|
||
canon_for_address (rtx x)
|
||
{
|
||
enum rtx_code code;
|
||
enum machine_mode mode;
|
||
rtx new = 0;
|
||
int i;
|
||
const char *fmt;
|
||
|
||
if (!x)
|
||
return x;
|
||
|
||
code = GET_CODE (x);
|
||
mode = GET_MODE (x);
|
||
|
||
switch (code)
|
||
{
|
||
case ASHIFT:
|
||
if (GET_CODE (XEXP (x, 1)) == CONST_INT
|
||
&& INTVAL (XEXP (x, 1)) < GET_MODE_BITSIZE (mode)
|
||
&& INTVAL (XEXP (x, 1)) >= 0)
|
||
{
|
||
new = canon_for_address (XEXP (x, 0));
|
||
new = gen_rtx_MULT (mode, new,
|
||
gen_int_mode ((HOST_WIDE_INT) 1
|
||
<< INTVAL (XEXP (x, 1)),
|
||
mode));
|
||
}
|
||
break;
|
||
default:
|
||
break;
|
||
|
||
}
|
||
if (new)
|
||
return new;
|
||
|
||
/* Now recursively process each operand of this operation. */
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = 0; i < GET_RTX_LENGTH (code); i++)
|
||
if (fmt[i] == 'e')
|
||
{
|
||
new = canon_for_address (XEXP (x, i));
|
||
XEXP (x, i) = new;
|
||
}
|
||
return x;
|
||
}
|
||
|
||
/* Return a negative value if an rtx A, whose costs are given by COST_A
|
||
and REGCOST_A, is more desirable than an rtx B.
|
||
Return a positive value if A is less desirable, or 0 if the two are
|
||
equally good. */
|
||
static int
|
||
preferable (int cost_a, int regcost_a, int cost_b, int regcost_b)
|
||
{
|
||
/* First, get rid of cases involving expressions that are entirely
|
||
unwanted. */
|
||
if (cost_a != cost_b)
|
||
{
|
||
if (cost_a == MAX_COST)
|
||
return 1;
|
||
if (cost_b == MAX_COST)
|
||
return -1;
|
||
}
|
||
|
||
/* Avoid extending lifetimes of hardregs. */
|
||
if (regcost_a != regcost_b)
|
||
{
|
||
if (regcost_a == MAX_COST)
|
||
return 1;
|
||
if (regcost_b == MAX_COST)
|
||
return -1;
|
||
}
|
||
|
||
/* Normal operation costs take precedence. */
|
||
if (cost_a != cost_b)
|
||
return cost_a - cost_b;
|
||
/* Only if these are identical consider effects on register pressure. */
|
||
if (regcost_a != regcost_b)
|
||
return regcost_a - regcost_b;
|
||
return 0;
|
||
}
|
||
|
||
/* Internal function, to compute cost when X is not a register; called
|
||
from COST macro to keep it simple. */
|
||
|
||
static int
|
||
notreg_cost (rtx x, enum rtx_code outer)
|
||
{
|
||
return ((GET_CODE (x) == SUBREG
|
||
&& REG_P (SUBREG_REG (x))
|
||
&& GET_MODE_CLASS (GET_MODE (x)) == MODE_INT
|
||
&& GET_MODE_CLASS (GET_MODE (SUBREG_REG (x))) == MODE_INT
|
||
&& (GET_MODE_SIZE (GET_MODE (x))
|
||
< GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
|
||
&& subreg_lowpart_p (x)
|
||
&& TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (GET_MODE (x)),
|
||
GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))))
|
||
? 0
|
||
: rtx_cost (x, outer) * 2);
|
||
}
|
||
|
||
|
||
/* Initialize CSE_REG_INFO_TABLE. */
|
||
|
||
static void
|
||
init_cse_reg_info (unsigned int nregs)
|
||
{
|
||
/* Do we need to grow the table? */
|
||
if (nregs > cse_reg_info_table_size)
|
||
{
|
||
unsigned int new_size;
|
||
|
||
if (cse_reg_info_table_size < 2048)
|
||
{
|
||
/* Compute a new size that is a power of 2 and no smaller
|
||
than the large of NREGS and 64. */
|
||
new_size = (cse_reg_info_table_size
|
||
? cse_reg_info_table_size : 64);
|
||
|
||
while (new_size < nregs)
|
||
new_size *= 2;
|
||
}
|
||
else
|
||
{
|
||
/* If we need a big table, allocate just enough to hold
|
||
NREGS registers. */
|
||
new_size = nregs;
|
||
}
|
||
|
||
/* Reallocate the table with NEW_SIZE entries. */
|
||
if (cse_reg_info_table)
|
||
free (cse_reg_info_table);
|
||
cse_reg_info_table = XNEWVEC (struct cse_reg_info, new_size);
|
||
cse_reg_info_table_size = new_size;
|
||
cse_reg_info_table_first_uninitialized = 0;
|
||
}
|
||
|
||
/* Do we have all of the first NREGS entries initialized? */
|
||
if (cse_reg_info_table_first_uninitialized < nregs)
|
||
{
|
||
unsigned int old_timestamp = cse_reg_info_timestamp - 1;
|
||
unsigned int i;
|
||
|
||
/* Put the old timestamp on newly allocated entries so that they
|
||
will all be considered out of date. We do not touch those
|
||
entries beyond the first NREGS entries to be nice to the
|
||
virtual memory. */
|
||
for (i = cse_reg_info_table_first_uninitialized; i < nregs; i++)
|
||
cse_reg_info_table[i].timestamp = old_timestamp;
|
||
|
||
cse_reg_info_table_first_uninitialized = nregs;
|
||
}
|
||
}
|
||
|
||
/* Given REGNO, initialize the cse_reg_info entry for REGNO. */
|
||
|
||
static void
|
||
get_cse_reg_info_1 (unsigned int regno)
|
||
{
|
||
/* Set TIMESTAMP field to CSE_REG_INFO_TIMESTAMP so that this
|
||
entry will be considered to have been initialized. */
|
||
cse_reg_info_table[regno].timestamp = cse_reg_info_timestamp;
|
||
|
||
/* Initialize the rest of the entry. */
|
||
cse_reg_info_table[regno].reg_tick = 1;
|
||
cse_reg_info_table[regno].reg_in_table = -1;
|
||
cse_reg_info_table[regno].subreg_ticked = -1;
|
||
cse_reg_info_table[regno].reg_qty = -regno - 1;
|
||
}
|
||
|
||
/* Find a cse_reg_info entry for REGNO. */
|
||
|
||
static inline struct cse_reg_info *
|
||
get_cse_reg_info (unsigned int regno)
|
||
{
|
||
struct cse_reg_info *p = &cse_reg_info_table[regno];
|
||
|
||
/* If this entry has not been initialized, go ahead and initialize
|
||
it. */
|
||
if (p->timestamp != cse_reg_info_timestamp)
|
||
get_cse_reg_info_1 (regno);
|
||
|
||
return p;
|
||
}
|
||
|
||
/* Clear the hash table and initialize each register with its own quantity,
|
||
for a new basic block. */
|
||
|
||
static void
|
||
new_basic_block (void)
|
||
{
|
||
int i;
|
||
|
||
next_qty = 0;
|
||
|
||
/* Invalidate cse_reg_info_table. */
|
||
cse_reg_info_timestamp++;
|
||
|
||
/* Clear out hash table state for this pass. */
|
||
CLEAR_HARD_REG_SET (hard_regs_in_table);
|
||
|
||
/* The per-quantity values used to be initialized here, but it is
|
||
much faster to initialize each as it is made in `make_new_qty'. */
|
||
|
||
for (i = 0; i < HASH_SIZE; i++)
|
||
{
|
||
struct table_elt *first;
|
||
|
||
first = table[i];
|
||
if (first != NULL)
|
||
{
|
||
struct table_elt *last = first;
|
||
|
||
table[i] = NULL;
|
||
|
||
while (last->next_same_hash != NULL)
|
||
last = last->next_same_hash;
|
||
|
||
/* Now relink this hash entire chain into
|
||
the free element list. */
|
||
|
||
last->next_same_hash = free_element_chain;
|
||
free_element_chain = first;
|
||
}
|
||
}
|
||
|
||
table_size = 0;
|
||
|
||
#ifdef HAVE_cc0
|
||
prev_insn = 0;
|
||
prev_insn_cc0 = 0;
|
||
#endif
|
||
}
|
||
|
||
/* Say that register REG contains a quantity in mode MODE not in any
|
||
register before and initialize that quantity. */
|
||
|
||
static void
|
||
make_new_qty (unsigned int reg, enum machine_mode mode)
|
||
{
|
||
int q;
|
||
struct qty_table_elem *ent;
|
||
struct reg_eqv_elem *eqv;
|
||
|
||
gcc_assert (next_qty < max_qty);
|
||
|
||
q = REG_QTY (reg) = next_qty++;
|
||
ent = &qty_table[q];
|
||
ent->first_reg = reg;
|
||
ent->last_reg = reg;
|
||
ent->mode = mode;
|
||
ent->const_rtx = ent->const_insn = NULL_RTX;
|
||
ent->comparison_code = UNKNOWN;
|
||
|
||
eqv = ®_eqv_table[reg];
|
||
eqv->next = eqv->prev = -1;
|
||
}
|
||
|
||
/* Make reg NEW equivalent to reg OLD.
|
||
OLD is not changing; NEW is. */
|
||
|
||
static void
|
||
make_regs_eqv (unsigned int new, unsigned int old)
|
||
{
|
||
unsigned int lastr, firstr;
|
||
int q = REG_QTY (old);
|
||
struct qty_table_elem *ent;
|
||
|
||
ent = &qty_table[q];
|
||
|
||
/* Nothing should become eqv until it has a "non-invalid" qty number. */
|
||
gcc_assert (REGNO_QTY_VALID_P (old));
|
||
|
||
REG_QTY (new) = q;
|
||
firstr = ent->first_reg;
|
||
lastr = ent->last_reg;
|
||
|
||
/* Prefer fixed hard registers to anything. Prefer pseudo regs to other
|
||
hard regs. Among pseudos, if NEW will live longer than any other reg
|
||
of the same qty, and that is beyond the current basic block,
|
||
make it the new canonical replacement for this qty. */
|
||
if (! (firstr < FIRST_PSEUDO_REGISTER && FIXED_REGNO_P (firstr))
|
||
/* Certain fixed registers might be of the class NO_REGS. This means
|
||
that not only can they not be allocated by the compiler, but
|
||
they cannot be used in substitutions or canonicalizations
|
||
either. */
|
||
&& (new >= FIRST_PSEUDO_REGISTER || REGNO_REG_CLASS (new) != NO_REGS)
|
||
&& ((new < FIRST_PSEUDO_REGISTER && FIXED_REGNO_P (new))
|
||
|| (new >= FIRST_PSEUDO_REGISTER
|
||
&& (firstr < FIRST_PSEUDO_REGISTER
|
||
|| ((uid_cuid[REGNO_LAST_UID (new)] > cse_basic_block_end
|
||
|| (uid_cuid[REGNO_FIRST_UID (new)]
|
||
< cse_basic_block_start))
|
||
&& (uid_cuid[REGNO_LAST_UID (new)]
|
||
> uid_cuid[REGNO_LAST_UID (firstr)]))))))
|
||
{
|
||
reg_eqv_table[firstr].prev = new;
|
||
reg_eqv_table[new].next = firstr;
|
||
reg_eqv_table[new].prev = -1;
|
||
ent->first_reg = new;
|
||
}
|
||
else
|
||
{
|
||
/* If NEW is a hard reg (known to be non-fixed), insert at end.
|
||
Otherwise, insert before any non-fixed hard regs that are at the
|
||
end. Registers of class NO_REGS cannot be used as an
|
||
equivalent for anything. */
|
||
while (lastr < FIRST_PSEUDO_REGISTER && reg_eqv_table[lastr].prev >= 0
|
||
&& (REGNO_REG_CLASS (lastr) == NO_REGS || ! FIXED_REGNO_P (lastr))
|
||
&& new >= FIRST_PSEUDO_REGISTER)
|
||
lastr = reg_eqv_table[lastr].prev;
|
||
reg_eqv_table[new].next = reg_eqv_table[lastr].next;
|
||
if (reg_eqv_table[lastr].next >= 0)
|
||
reg_eqv_table[reg_eqv_table[lastr].next].prev = new;
|
||
else
|
||
qty_table[q].last_reg = new;
|
||
reg_eqv_table[lastr].next = new;
|
||
reg_eqv_table[new].prev = lastr;
|
||
}
|
||
}
|
||
|
||
/* Remove REG from its equivalence class. */
|
||
|
||
static void
|
||
delete_reg_equiv (unsigned int reg)
|
||
{
|
||
struct qty_table_elem *ent;
|
||
int q = REG_QTY (reg);
|
||
int p, n;
|
||
|
||
/* If invalid, do nothing. */
|
||
if (! REGNO_QTY_VALID_P (reg))
|
||
return;
|
||
|
||
ent = &qty_table[q];
|
||
|
||
p = reg_eqv_table[reg].prev;
|
||
n = reg_eqv_table[reg].next;
|
||
|
||
if (n != -1)
|
||
reg_eqv_table[n].prev = p;
|
||
else
|
||
ent->last_reg = p;
|
||
if (p != -1)
|
||
reg_eqv_table[p].next = n;
|
||
else
|
||
ent->first_reg = n;
|
||
|
||
REG_QTY (reg) = -reg - 1;
|
||
}
|
||
|
||
/* Remove any invalid expressions from the hash table
|
||
that refer to any of the registers contained in expression X.
|
||
|
||
Make sure that newly inserted references to those registers
|
||
as subexpressions will be considered valid.
|
||
|
||
mention_regs is not called when a register itself
|
||
is being stored in the table.
|
||
|
||
Return 1 if we have done something that may have changed the hash code
|
||
of X. */
|
||
|
||
static int
|
||
mention_regs (rtx x)
|
||
{
|
||
enum rtx_code code;
|
||
int i, j;
|
||
const char *fmt;
|
||
int changed = 0;
|
||
|
||
if (x == 0)
|
||
return 0;
|
||
|
||
code = GET_CODE (x);
|
||
if (code == REG)
|
||
{
|
||
unsigned int regno = REGNO (x);
|
||
unsigned int endregno
|
||
= regno + (regno >= FIRST_PSEUDO_REGISTER ? 1
|
||
: hard_regno_nregs[regno][GET_MODE (x)]);
|
||
unsigned int i;
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
{
|
||
if (REG_IN_TABLE (i) >= 0 && REG_IN_TABLE (i) != REG_TICK (i))
|
||
remove_invalid_refs (i);
|
||
|
||
REG_IN_TABLE (i) = REG_TICK (i);
|
||
SUBREG_TICKED (i) = -1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* If this is a SUBREG, we don't want to discard other SUBREGs of the same
|
||
pseudo if they don't use overlapping words. We handle only pseudos
|
||
here for simplicity. */
|
||
if (code == SUBREG && REG_P (SUBREG_REG (x))
|
||
&& REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER)
|
||
{
|
||
unsigned int i = REGNO (SUBREG_REG (x));
|
||
|
||
if (REG_IN_TABLE (i) >= 0 && REG_IN_TABLE (i) != REG_TICK (i))
|
||
{
|
||
/* If REG_IN_TABLE (i) differs from REG_TICK (i) by one, and
|
||
the last store to this register really stored into this
|
||
subreg, then remove the memory of this subreg.
|
||
Otherwise, remove any memory of the entire register and
|
||
all its subregs from the table. */
|
||
if (REG_TICK (i) - REG_IN_TABLE (i) > 1
|
||
|| SUBREG_TICKED (i) != REGNO (SUBREG_REG (x)))
|
||
remove_invalid_refs (i);
|
||
else
|
||
remove_invalid_subreg_refs (i, SUBREG_BYTE (x), GET_MODE (x));
|
||
}
|
||
|
||
REG_IN_TABLE (i) = REG_TICK (i);
|
||
SUBREG_TICKED (i) = REGNO (SUBREG_REG (x));
|
||
return 0;
|
||
}
|
||
|
||
/* If X is a comparison or a COMPARE and either operand is a register
|
||
that does not have a quantity, give it one. This is so that a later
|
||
call to record_jump_equiv won't cause X to be assigned a different
|
||
hash code and not found in the table after that call.
|
||
|
||
It is not necessary to do this here, since rehash_using_reg can
|
||
fix up the table later, but doing this here eliminates the need to
|
||
call that expensive function in the most common case where the only
|
||
use of the register is in the comparison. */
|
||
|
||
if (code == COMPARE || COMPARISON_P (x))
|
||
{
|
||
if (REG_P (XEXP (x, 0))
|
||
&& ! REGNO_QTY_VALID_P (REGNO (XEXP (x, 0))))
|
||
if (insert_regs (XEXP (x, 0), NULL, 0))
|
||
{
|
||
rehash_using_reg (XEXP (x, 0));
|
||
changed = 1;
|
||
}
|
||
|
||
if (REG_P (XEXP (x, 1))
|
||
&& ! REGNO_QTY_VALID_P (REGNO (XEXP (x, 1))))
|
||
if (insert_regs (XEXP (x, 1), NULL, 0))
|
||
{
|
||
rehash_using_reg (XEXP (x, 1));
|
||
changed = 1;
|
||
}
|
||
}
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
if (fmt[i] == 'e')
|
||
changed |= mention_regs (XEXP (x, i));
|
||
else if (fmt[i] == 'E')
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
changed |= mention_regs (XVECEXP (x, i, j));
|
||
|
||
return changed;
|
||
}
|
||
|
||
/* Update the register quantities for inserting X into the hash table
|
||
with a value equivalent to CLASSP.
|
||
(If the class does not contain a REG, it is irrelevant.)
|
||
If MODIFIED is nonzero, X is a destination; it is being modified.
|
||
Note that delete_reg_equiv should be called on a register
|
||
before insert_regs is done on that register with MODIFIED != 0.
|
||
|
||
Nonzero value means that elements of reg_qty have changed
|
||
so X's hash code may be different. */
|
||
|
||
static int
|
||
insert_regs (rtx x, struct table_elt *classp, int modified)
|
||
{
|
||
if (REG_P (x))
|
||
{
|
||
unsigned int regno = REGNO (x);
|
||
int qty_valid;
|
||
|
||
/* If REGNO is in the equivalence table already but is of the
|
||
wrong mode for that equivalence, don't do anything here. */
|
||
|
||
qty_valid = REGNO_QTY_VALID_P (regno);
|
||
if (qty_valid)
|
||
{
|
||
struct qty_table_elem *ent = &qty_table[REG_QTY (regno)];
|
||
|
||
if (ent->mode != GET_MODE (x))
|
||
return 0;
|
||
}
|
||
|
||
if (modified || ! qty_valid)
|
||
{
|
||
if (classp)
|
||
for (classp = classp->first_same_value;
|
||
classp != 0;
|
||
classp = classp->next_same_value)
|
||
if (REG_P (classp->exp)
|
||
&& GET_MODE (classp->exp) == GET_MODE (x))
|
||
{
|
||
unsigned c_regno = REGNO (classp->exp);
|
||
|
||
gcc_assert (REGNO_QTY_VALID_P (c_regno));
|
||
|
||
/* Suppose that 5 is hard reg and 100 and 101 are
|
||
pseudos. Consider
|
||
|
||
(set (reg:si 100) (reg:si 5))
|
||
(set (reg:si 5) (reg:si 100))
|
||
(set (reg:di 101) (reg:di 5))
|
||
|
||
We would now set REG_QTY (101) = REG_QTY (5), but the
|
||
entry for 5 is in SImode. When we use this later in
|
||
copy propagation, we get the register in wrong mode. */
|
||
if (qty_table[REG_QTY (c_regno)].mode != GET_MODE (x))
|
||
continue;
|
||
|
||
make_regs_eqv (regno, c_regno);
|
||
return 1;
|
||
}
|
||
|
||
/* Mention_regs for a SUBREG checks if REG_TICK is exactly one larger
|
||
than REG_IN_TABLE to find out if there was only a single preceding
|
||
invalidation - for the SUBREG - or another one, which would be
|
||
for the full register. However, if we find here that REG_TICK
|
||
indicates that the register is invalid, it means that it has
|
||
been invalidated in a separate operation. The SUBREG might be used
|
||
now (then this is a recursive call), or we might use the full REG
|
||
now and a SUBREG of it later. So bump up REG_TICK so that
|
||
mention_regs will do the right thing. */
|
||
if (! modified
|
||
&& REG_IN_TABLE (regno) >= 0
|
||
&& REG_TICK (regno) == REG_IN_TABLE (regno) + 1)
|
||
REG_TICK (regno)++;
|
||
make_new_qty (regno, GET_MODE (x));
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* If X is a SUBREG, we will likely be inserting the inner register in the
|
||
table. If that register doesn't have an assigned quantity number at
|
||
this point but does later, the insertion that we will be doing now will
|
||
not be accessible because its hash code will have changed. So assign
|
||
a quantity number now. */
|
||
|
||
else if (GET_CODE (x) == SUBREG && REG_P (SUBREG_REG (x))
|
||
&& ! REGNO_QTY_VALID_P (REGNO (SUBREG_REG (x))))
|
||
{
|
||
insert_regs (SUBREG_REG (x), NULL, 0);
|
||
mention_regs (x);
|
||
return 1;
|
||
}
|
||
else
|
||
return mention_regs (x);
|
||
}
|
||
|
||
/* Look in or update the hash table. */
|
||
|
||
/* Remove table element ELT from use in the table.
|
||
HASH is its hash code, made using the HASH macro.
|
||
It's an argument because often that is known in advance
|
||
and we save much time not recomputing it. */
|
||
|
||
static void
|
||
remove_from_table (struct table_elt *elt, unsigned int hash)
|
||
{
|
||
if (elt == 0)
|
||
return;
|
||
|
||
/* Mark this element as removed. See cse_insn. */
|
||
elt->first_same_value = 0;
|
||
|
||
/* Remove the table element from its equivalence class. */
|
||
|
||
{
|
||
struct table_elt *prev = elt->prev_same_value;
|
||
struct table_elt *next = elt->next_same_value;
|
||
|
||
if (next)
|
||
next->prev_same_value = prev;
|
||
|
||
if (prev)
|
||
prev->next_same_value = next;
|
||
else
|
||
{
|
||
struct table_elt *newfirst = next;
|
||
while (next)
|
||
{
|
||
next->first_same_value = newfirst;
|
||
next = next->next_same_value;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Remove the table element from its hash bucket. */
|
||
|
||
{
|
||
struct table_elt *prev = elt->prev_same_hash;
|
||
struct table_elt *next = elt->next_same_hash;
|
||
|
||
if (next)
|
||
next->prev_same_hash = prev;
|
||
|
||
if (prev)
|
||
prev->next_same_hash = next;
|
||
else if (table[hash] == elt)
|
||
table[hash] = next;
|
||
else
|
||
{
|
||
/* This entry is not in the proper hash bucket. This can happen
|
||
when two classes were merged by `merge_equiv_classes'. Search
|
||
for the hash bucket that it heads. This happens only very
|
||
rarely, so the cost is acceptable. */
|
||
for (hash = 0; hash < HASH_SIZE; hash++)
|
||
if (table[hash] == elt)
|
||
table[hash] = next;
|
||
}
|
||
}
|
||
|
||
/* Remove the table element from its related-value circular chain. */
|
||
|
||
if (elt->related_value != 0 && elt->related_value != elt)
|
||
{
|
||
struct table_elt *p = elt->related_value;
|
||
|
||
while (p->related_value != elt)
|
||
p = p->related_value;
|
||
p->related_value = elt->related_value;
|
||
if (p->related_value == p)
|
||
p->related_value = 0;
|
||
}
|
||
|
||
/* Now add it to the free element chain. */
|
||
elt->next_same_hash = free_element_chain;
|
||
free_element_chain = elt;
|
||
|
||
table_size--;
|
||
}
|
||
|
||
/* Look up X in the hash table and return its table element,
|
||
or 0 if X is not in the table.
|
||
|
||
MODE is the machine-mode of X, or if X is an integer constant
|
||
with VOIDmode then MODE is the mode with which X will be used.
|
||
|
||
Here we are satisfied to find an expression whose tree structure
|
||
looks like X. */
|
||
|
||
static struct table_elt *
|
||
lookup (rtx x, unsigned int hash, enum machine_mode mode)
|
||
{
|
||
struct table_elt *p;
|
||
|
||
for (p = table[hash]; p; p = p->next_same_hash)
|
||
if (mode == p->mode && ((x == p->exp && REG_P (x))
|
||
|| exp_equiv_p (x, p->exp, !REG_P (x), false)))
|
||
return p;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Like `lookup' but don't care whether the table element uses invalid regs.
|
||
Also ignore discrepancies in the machine mode of a register. */
|
||
|
||
static struct table_elt *
|
||
lookup_for_remove (rtx x, unsigned int hash, enum machine_mode mode)
|
||
{
|
||
struct table_elt *p;
|
||
|
||
if (REG_P (x))
|
||
{
|
||
unsigned int regno = REGNO (x);
|
||
|
||
/* Don't check the machine mode when comparing registers;
|
||
invalidating (REG:SI 0) also invalidates (REG:DF 0). */
|
||
for (p = table[hash]; p; p = p->next_same_hash)
|
||
if (REG_P (p->exp)
|
||
&& REGNO (p->exp) == regno)
|
||
return p;
|
||
}
|
||
else
|
||
{
|
||
for (p = table[hash]; p; p = p->next_same_hash)
|
||
if (mode == p->mode
|
||
&& (x == p->exp || exp_equiv_p (x, p->exp, 0, false)))
|
||
return p;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Look for an expression equivalent to X and with code CODE.
|
||
If one is found, return that expression. */
|
||
|
||
static rtx
|
||
lookup_as_function (rtx x, enum rtx_code code)
|
||
{
|
||
struct table_elt *p
|
||
= lookup (x, SAFE_HASH (x, VOIDmode), GET_MODE (x));
|
||
|
||
/* If we are looking for a CONST_INT, the mode doesn't really matter, as
|
||
long as we are narrowing. So if we looked in vain for a mode narrower
|
||
than word_mode before, look for word_mode now. */
|
||
if (p == 0 && code == CONST_INT
|
||
&& GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (word_mode))
|
||
{
|
||
x = copy_rtx (x);
|
||
PUT_MODE (x, word_mode);
|
||
p = lookup (x, SAFE_HASH (x, VOIDmode), word_mode);
|
||
}
|
||
|
||
if (p == 0)
|
||
return 0;
|
||
|
||
for (p = p->first_same_value; p; p = p->next_same_value)
|
||
if (GET_CODE (p->exp) == code
|
||
/* Make sure this is a valid entry in the table. */
|
||
&& exp_equiv_p (p->exp, p->exp, 1, false))
|
||
return p->exp;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Insert X in the hash table, assuming HASH is its hash code
|
||
and CLASSP is an element of the class it should go in
|
||
(or 0 if a new class should be made).
|
||
It is inserted at the proper position to keep the class in
|
||
the order cheapest first.
|
||
|
||
MODE is the machine-mode of X, or if X is an integer constant
|
||
with VOIDmode then MODE is the mode with which X will be used.
|
||
|
||
For elements of equal cheapness, the most recent one
|
||
goes in front, except that the first element in the list
|
||
remains first unless a cheaper element is added. The order of
|
||
pseudo-registers does not matter, as canon_reg will be called to
|
||
find the cheapest when a register is retrieved from the table.
|
||
|
||
The in_memory field in the hash table element is set to 0.
|
||
The caller must set it nonzero if appropriate.
|
||
|
||
You should call insert_regs (X, CLASSP, MODIFY) before calling here,
|
||
and if insert_regs returns a nonzero value
|
||
you must then recompute its hash code before calling here.
|
||
|
||
If necessary, update table showing constant values of quantities. */
|
||
|
||
#define CHEAPER(X, Y) \
|
||
(preferable ((X)->cost, (X)->regcost, (Y)->cost, (Y)->regcost) < 0)
|
||
|
||
static struct table_elt *
|
||
insert (rtx x, struct table_elt *classp, unsigned int hash, enum machine_mode mode)
|
||
{
|
||
struct table_elt *elt;
|
||
|
||
/* If X is a register and we haven't made a quantity for it,
|
||
something is wrong. */
|
||
gcc_assert (!REG_P (x) || REGNO_QTY_VALID_P (REGNO (x)));
|
||
|
||
/* If X is a hard register, show it is being put in the table. */
|
||
if (REG_P (x) && REGNO (x) < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
unsigned int regno = REGNO (x);
|
||
unsigned int endregno = regno + hard_regno_nregs[regno][GET_MODE (x)];
|
||
unsigned int i;
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
SET_HARD_REG_BIT (hard_regs_in_table, i);
|
||
}
|
||
|
||
/* Put an element for X into the right hash bucket. */
|
||
|
||
elt = free_element_chain;
|
||
if (elt)
|
||
free_element_chain = elt->next_same_hash;
|
||
else
|
||
elt = XNEW (struct table_elt);
|
||
|
||
elt->exp = x;
|
||
elt->canon_exp = NULL_RTX;
|
||
elt->cost = COST (x);
|
||
elt->regcost = approx_reg_cost (x);
|
||
elt->next_same_value = 0;
|
||
elt->prev_same_value = 0;
|
||
elt->next_same_hash = table[hash];
|
||
elt->prev_same_hash = 0;
|
||
elt->related_value = 0;
|
||
elt->in_memory = 0;
|
||
elt->mode = mode;
|
||
elt->is_const = (CONSTANT_P (x) || fixed_base_plus_p (x));
|
||
|
||
if (table[hash])
|
||
table[hash]->prev_same_hash = elt;
|
||
table[hash] = elt;
|
||
|
||
/* Put it into the proper value-class. */
|
||
if (classp)
|
||
{
|
||
classp = classp->first_same_value;
|
||
if (CHEAPER (elt, classp))
|
||
/* Insert at the head of the class. */
|
||
{
|
||
struct table_elt *p;
|
||
elt->next_same_value = classp;
|
||
classp->prev_same_value = elt;
|
||
elt->first_same_value = elt;
|
||
|
||
for (p = classp; p; p = p->next_same_value)
|
||
p->first_same_value = elt;
|
||
}
|
||
else
|
||
{
|
||
/* Insert not at head of the class. */
|
||
/* Put it after the last element cheaper than X. */
|
||
struct table_elt *p, *next;
|
||
|
||
for (p = classp; (next = p->next_same_value) && CHEAPER (next, elt);
|
||
p = next);
|
||
|
||
/* Put it after P and before NEXT. */
|
||
elt->next_same_value = next;
|
||
if (next)
|
||
next->prev_same_value = elt;
|
||
|
||
elt->prev_same_value = p;
|
||
p->next_same_value = elt;
|
||
elt->first_same_value = classp;
|
||
}
|
||
}
|
||
else
|
||
elt->first_same_value = elt;
|
||
|
||
/* If this is a constant being set equivalent to a register or a register
|
||
being set equivalent to a constant, note the constant equivalence.
|
||
|
||
If this is a constant, it cannot be equivalent to a different constant,
|
||
and a constant is the only thing that can be cheaper than a register. So
|
||
we know the register is the head of the class (before the constant was
|
||
inserted).
|
||
|
||
If this is a register that is not already known equivalent to a
|
||
constant, we must check the entire class.
|
||
|
||
If this is a register that is already known equivalent to an insn,
|
||
update the qtys `const_insn' to show that `this_insn' is the latest
|
||
insn making that quantity equivalent to the constant. */
|
||
|
||
if (elt->is_const && classp && REG_P (classp->exp)
|
||
&& !REG_P (x))
|
||
{
|
||
int exp_q = REG_QTY (REGNO (classp->exp));
|
||
struct qty_table_elem *exp_ent = &qty_table[exp_q];
|
||
|
||
exp_ent->const_rtx = gen_lowpart (exp_ent->mode, x);
|
||
exp_ent->const_insn = this_insn;
|
||
}
|
||
|
||
else if (REG_P (x)
|
||
&& classp
|
||
&& ! qty_table[REG_QTY (REGNO (x))].const_rtx
|
||
&& ! elt->is_const)
|
||
{
|
||
struct table_elt *p;
|
||
|
||
for (p = classp; p != 0; p = p->next_same_value)
|
||
{
|
||
if (p->is_const && !REG_P (p->exp))
|
||
{
|
||
int x_q = REG_QTY (REGNO (x));
|
||
struct qty_table_elem *x_ent = &qty_table[x_q];
|
||
|
||
x_ent->const_rtx
|
||
= gen_lowpart (GET_MODE (x), p->exp);
|
||
x_ent->const_insn = this_insn;
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
else if (REG_P (x)
|
||
&& qty_table[REG_QTY (REGNO (x))].const_rtx
|
||
&& GET_MODE (x) == qty_table[REG_QTY (REGNO (x))].mode)
|
||
qty_table[REG_QTY (REGNO (x))].const_insn = this_insn;
|
||
|
||
/* If this is a constant with symbolic value,
|
||
and it has a term with an explicit integer value,
|
||
link it up with related expressions. */
|
||
if (GET_CODE (x) == CONST)
|
||
{
|
||
rtx subexp = get_related_value (x);
|
||
unsigned subhash;
|
||
struct table_elt *subelt, *subelt_prev;
|
||
|
||
if (subexp != 0)
|
||
{
|
||
/* Get the integer-free subexpression in the hash table. */
|
||
subhash = SAFE_HASH (subexp, mode);
|
||
subelt = lookup (subexp, subhash, mode);
|
||
if (subelt == 0)
|
||
subelt = insert (subexp, NULL, subhash, mode);
|
||
/* Initialize SUBELT's circular chain if it has none. */
|
||
if (subelt->related_value == 0)
|
||
subelt->related_value = subelt;
|
||
/* Find the element in the circular chain that precedes SUBELT. */
|
||
subelt_prev = subelt;
|
||
while (subelt_prev->related_value != subelt)
|
||
subelt_prev = subelt_prev->related_value;
|
||
/* Put new ELT into SUBELT's circular chain just before SUBELT.
|
||
This way the element that follows SUBELT is the oldest one. */
|
||
elt->related_value = subelt_prev->related_value;
|
||
subelt_prev->related_value = elt;
|
||
}
|
||
}
|
||
|
||
table_size++;
|
||
|
||
return elt;
|
||
}
|
||
|
||
/* Given two equivalence classes, CLASS1 and CLASS2, put all the entries from
|
||
CLASS2 into CLASS1. This is done when we have reached an insn which makes
|
||
the two classes equivalent.
|
||
|
||
CLASS1 will be the surviving class; CLASS2 should not be used after this
|
||
call.
|
||
|
||
Any invalid entries in CLASS2 will not be copied. */
|
||
|
||
static void
|
||
merge_equiv_classes (struct table_elt *class1, struct table_elt *class2)
|
||
{
|
||
struct table_elt *elt, *next, *new;
|
||
|
||
/* Ensure we start with the head of the classes. */
|
||
class1 = class1->first_same_value;
|
||
class2 = class2->first_same_value;
|
||
|
||
/* If they were already equal, forget it. */
|
||
if (class1 == class2)
|
||
return;
|
||
|
||
for (elt = class2; elt; elt = next)
|
||
{
|
||
unsigned int hash;
|
||
rtx exp = elt->exp;
|
||
enum machine_mode mode = elt->mode;
|
||
|
||
next = elt->next_same_value;
|
||
|
||
/* Remove old entry, make a new one in CLASS1's class.
|
||
Don't do this for invalid entries as we cannot find their
|
||
hash code (it also isn't necessary). */
|
||
if (REG_P (exp) || exp_equiv_p (exp, exp, 1, false))
|
||
{
|
||
bool need_rehash = false;
|
||
|
||
hash_arg_in_memory = 0;
|
||
hash = HASH (exp, mode);
|
||
|
||
if (REG_P (exp))
|
||
{
|
||
need_rehash = REGNO_QTY_VALID_P (REGNO (exp));
|
||
delete_reg_equiv (REGNO (exp));
|
||
}
|
||
|
||
remove_from_table (elt, hash);
|
||
|
||
if (insert_regs (exp, class1, 0) || need_rehash)
|
||
{
|
||
rehash_using_reg (exp);
|
||
hash = HASH (exp, mode);
|
||
}
|
||
new = insert (exp, class1, hash, mode);
|
||
new->in_memory = hash_arg_in_memory;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Flush the entire hash table. */
|
||
|
||
static void
|
||
flush_hash_table (void)
|
||
{
|
||
int i;
|
||
struct table_elt *p;
|
||
|
||
for (i = 0; i < HASH_SIZE; i++)
|
||
for (p = table[i]; p; p = table[i])
|
||
{
|
||
/* Note that invalidate can remove elements
|
||
after P in the current hash chain. */
|
||
if (REG_P (p->exp))
|
||
invalidate (p->exp, VOIDmode);
|
||
else
|
||
remove_from_table (p, i);
|
||
}
|
||
}
|
||
|
||
/* Function called for each rtx to check whether true dependence exist. */
|
||
struct check_dependence_data
|
||
{
|
||
enum machine_mode mode;
|
||
rtx exp;
|
||
rtx addr;
|
||
};
|
||
|
||
static int
|
||
check_dependence (rtx *x, void *data)
|
||
{
|
||
struct check_dependence_data *d = (struct check_dependence_data *) data;
|
||
if (*x && MEM_P (*x))
|
||
return canon_true_dependence (d->exp, d->mode, d->addr, *x,
|
||
cse_rtx_varies_p);
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
/* Remove from the hash table, or mark as invalid, all expressions whose
|
||
values could be altered by storing in X. X is a register, a subreg, or
|
||
a memory reference with nonvarying address (because, when a memory
|
||
reference with a varying address is stored in, all memory references are
|
||
removed by invalidate_memory so specific invalidation is superfluous).
|
||
FULL_MODE, if not VOIDmode, indicates that this much should be
|
||
invalidated instead of just the amount indicated by the mode of X. This
|
||
is only used for bitfield stores into memory.
|
||
|
||
A nonvarying address may be just a register or just a symbol reference,
|
||
or it may be either of those plus a numeric offset. */
|
||
|
||
static void
|
||
invalidate (rtx x, enum machine_mode full_mode)
|
||
{
|
||
int i;
|
||
struct table_elt *p;
|
||
rtx addr;
|
||
|
||
switch (GET_CODE (x))
|
||
{
|
||
case REG:
|
||
{
|
||
/* If X is a register, dependencies on its contents are recorded
|
||
through the qty number mechanism. Just change the qty number of
|
||
the register, mark it as invalid for expressions that refer to it,
|
||
and remove it itself. */
|
||
unsigned int regno = REGNO (x);
|
||
unsigned int hash = HASH (x, GET_MODE (x));
|
||
|
||
/* Remove REGNO from any quantity list it might be on and indicate
|
||
that its value might have changed. If it is a pseudo, remove its
|
||
entry from the hash table.
|
||
|
||
For a hard register, we do the first two actions above for any
|
||
additional hard registers corresponding to X. Then, if any of these
|
||
registers are in the table, we must remove any REG entries that
|
||
overlap these registers. */
|
||
|
||
delete_reg_equiv (regno);
|
||
REG_TICK (regno)++;
|
||
SUBREG_TICKED (regno) = -1;
|
||
|
||
if (regno >= FIRST_PSEUDO_REGISTER)
|
||
{
|
||
/* Because a register can be referenced in more than one mode,
|
||
we might have to remove more than one table entry. */
|
||
struct table_elt *elt;
|
||
|
||
while ((elt = lookup_for_remove (x, hash, GET_MODE (x))))
|
||
remove_from_table (elt, hash);
|
||
}
|
||
else
|
||
{
|
||
HOST_WIDE_INT in_table
|
||
= TEST_HARD_REG_BIT (hard_regs_in_table, regno);
|
||
unsigned int endregno
|
||
= regno + hard_regno_nregs[regno][GET_MODE (x)];
|
||
unsigned int tregno, tendregno, rn;
|
||
struct table_elt *p, *next;
|
||
|
||
CLEAR_HARD_REG_BIT (hard_regs_in_table, regno);
|
||
|
||
for (rn = regno + 1; rn < endregno; rn++)
|
||
{
|
||
in_table |= TEST_HARD_REG_BIT (hard_regs_in_table, rn);
|
||
CLEAR_HARD_REG_BIT (hard_regs_in_table, rn);
|
||
delete_reg_equiv (rn);
|
||
REG_TICK (rn)++;
|
||
SUBREG_TICKED (rn) = -1;
|
||
}
|
||
|
||
if (in_table)
|
||
for (hash = 0; hash < HASH_SIZE; hash++)
|
||
for (p = table[hash]; p; p = next)
|
||
{
|
||
next = p->next_same_hash;
|
||
|
||
if (!REG_P (p->exp)
|
||
|| REGNO (p->exp) >= FIRST_PSEUDO_REGISTER)
|
||
continue;
|
||
|
||
tregno = REGNO (p->exp);
|
||
tendregno
|
||
= tregno + hard_regno_nregs[tregno][GET_MODE (p->exp)];
|
||
if (tendregno > regno && tregno < endregno)
|
||
remove_from_table (p, hash);
|
||
}
|
||
}
|
||
}
|
||
return;
|
||
|
||
case SUBREG:
|
||
invalidate (SUBREG_REG (x), VOIDmode);
|
||
return;
|
||
|
||
case PARALLEL:
|
||
for (i = XVECLEN (x, 0) - 1; i >= 0; --i)
|
||
invalidate (XVECEXP (x, 0, i), VOIDmode);
|
||
return;
|
||
|
||
case EXPR_LIST:
|
||
/* This is part of a disjoint return value; extract the location in
|
||
question ignoring the offset. */
|
||
invalidate (XEXP (x, 0), VOIDmode);
|
||
return;
|
||
|
||
case MEM:
|
||
addr = canon_rtx (get_addr (XEXP (x, 0)));
|
||
/* Calculate the canonical version of X here so that
|
||
true_dependence doesn't generate new RTL for X on each call. */
|
||
x = canon_rtx (x);
|
||
|
||
/* Remove all hash table elements that refer to overlapping pieces of
|
||
memory. */
|
||
if (full_mode == VOIDmode)
|
||
full_mode = GET_MODE (x);
|
||
|
||
for (i = 0; i < HASH_SIZE; i++)
|
||
{
|
||
struct table_elt *next;
|
||
|
||
for (p = table[i]; p; p = next)
|
||
{
|
||
next = p->next_same_hash;
|
||
if (p->in_memory)
|
||
{
|
||
struct check_dependence_data d;
|
||
|
||
/* Just canonicalize the expression once;
|
||
otherwise each time we call invalidate
|
||
true_dependence will canonicalize the
|
||
expression again. */
|
||
if (!p->canon_exp)
|
||
p->canon_exp = canon_rtx (p->exp);
|
||
d.exp = x;
|
||
d.addr = addr;
|
||
d.mode = full_mode;
|
||
if (for_each_rtx (&p->canon_exp, check_dependence, &d))
|
||
remove_from_table (p, i);
|
||
}
|
||
}
|
||
}
|
||
return;
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
}
|
||
|
||
/* Remove all expressions that refer to register REGNO,
|
||
since they are already invalid, and we are about to
|
||
mark that register valid again and don't want the old
|
||
expressions to reappear as valid. */
|
||
|
||
static void
|
||
remove_invalid_refs (unsigned int regno)
|
||
{
|
||
unsigned int i;
|
||
struct table_elt *p, *next;
|
||
|
||
for (i = 0; i < HASH_SIZE; i++)
|
||
for (p = table[i]; p; p = next)
|
||
{
|
||
next = p->next_same_hash;
|
||
if (!REG_P (p->exp)
|
||
&& refers_to_regno_p (regno, regno + 1, p->exp, (rtx *) 0))
|
||
remove_from_table (p, i);
|
||
}
|
||
}
|
||
|
||
/* Likewise for a subreg with subreg_reg REGNO, subreg_byte OFFSET,
|
||
and mode MODE. */
|
||
static void
|
||
remove_invalid_subreg_refs (unsigned int regno, unsigned int offset,
|
||
enum machine_mode mode)
|
||
{
|
||
unsigned int i;
|
||
struct table_elt *p, *next;
|
||
unsigned int end = offset + (GET_MODE_SIZE (mode) - 1);
|
||
|
||
for (i = 0; i < HASH_SIZE; i++)
|
||
for (p = table[i]; p; p = next)
|
||
{
|
||
rtx exp = p->exp;
|
||
next = p->next_same_hash;
|
||
|
||
if (!REG_P (exp)
|
||
&& (GET_CODE (exp) != SUBREG
|
||
|| !REG_P (SUBREG_REG (exp))
|
||
|| REGNO (SUBREG_REG (exp)) != regno
|
||
|| (((SUBREG_BYTE (exp)
|
||
+ (GET_MODE_SIZE (GET_MODE (exp)) - 1)) >= offset)
|
||
&& SUBREG_BYTE (exp) <= end))
|
||
&& refers_to_regno_p (regno, regno + 1, p->exp, (rtx *) 0))
|
||
remove_from_table (p, i);
|
||
}
|
||
}
|
||
|
||
/* Recompute the hash codes of any valid entries in the hash table that
|
||
reference X, if X is a register, or SUBREG_REG (X) if X is a SUBREG.
|
||
|
||
This is called when we make a jump equivalence. */
|
||
|
||
static void
|
||
rehash_using_reg (rtx x)
|
||
{
|
||
unsigned int i;
|
||
struct table_elt *p, *next;
|
||
unsigned hash;
|
||
|
||
if (GET_CODE (x) == SUBREG)
|
||
x = SUBREG_REG (x);
|
||
|
||
/* If X is not a register or if the register is known not to be in any
|
||
valid entries in the table, we have no work to do. */
|
||
|
||
if (!REG_P (x)
|
||
|| REG_IN_TABLE (REGNO (x)) < 0
|
||
|| REG_IN_TABLE (REGNO (x)) != REG_TICK (REGNO (x)))
|
||
return;
|
||
|
||
/* Scan all hash chains looking for valid entries that mention X.
|
||
If we find one and it is in the wrong hash chain, move it. */
|
||
|
||
for (i = 0; i < HASH_SIZE; i++)
|
||
for (p = table[i]; p; p = next)
|
||
{
|
||
next = p->next_same_hash;
|
||
if (reg_mentioned_p (x, p->exp)
|
||
&& exp_equiv_p (p->exp, p->exp, 1, false)
|
||
&& i != (hash = SAFE_HASH (p->exp, p->mode)))
|
||
{
|
||
if (p->next_same_hash)
|
||
p->next_same_hash->prev_same_hash = p->prev_same_hash;
|
||
|
||
if (p->prev_same_hash)
|
||
p->prev_same_hash->next_same_hash = p->next_same_hash;
|
||
else
|
||
table[i] = p->next_same_hash;
|
||
|
||
p->next_same_hash = table[hash];
|
||
p->prev_same_hash = 0;
|
||
if (table[hash])
|
||
table[hash]->prev_same_hash = p;
|
||
table[hash] = p;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Remove from the hash table any expression that is a call-clobbered
|
||
register. Also update their TICK values. */
|
||
|
||
static void
|
||
invalidate_for_call (void)
|
||
{
|
||
unsigned int regno, endregno;
|
||
unsigned int i;
|
||
unsigned hash;
|
||
struct table_elt *p, *next;
|
||
int in_table = 0;
|
||
|
||
/* Go through all the hard registers. For each that is clobbered in
|
||
a CALL_INSN, remove the register from quantity chains and update
|
||
reg_tick if defined. Also see if any of these registers is currently
|
||
in the table. */
|
||
|
||
for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
|
||
if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
|
||
{
|
||
delete_reg_equiv (regno);
|
||
if (REG_TICK (regno) >= 0)
|
||
{
|
||
REG_TICK (regno)++;
|
||
SUBREG_TICKED (regno) = -1;
|
||
}
|
||
|
||
in_table |= (TEST_HARD_REG_BIT (hard_regs_in_table, regno) != 0);
|
||
}
|
||
|
||
/* In the case where we have no call-clobbered hard registers in the
|
||
table, we are done. Otherwise, scan the table and remove any
|
||
entry that overlaps a call-clobbered register. */
|
||
|
||
if (in_table)
|
||
for (hash = 0; hash < HASH_SIZE; hash++)
|
||
for (p = table[hash]; p; p = next)
|
||
{
|
||
next = p->next_same_hash;
|
||
|
||
if (!REG_P (p->exp)
|
||
|| REGNO (p->exp) >= FIRST_PSEUDO_REGISTER)
|
||
continue;
|
||
|
||
regno = REGNO (p->exp);
|
||
endregno = regno + hard_regno_nregs[regno][GET_MODE (p->exp)];
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
|
||
{
|
||
remove_from_table (p, hash);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Given an expression X of type CONST,
|
||
and ELT which is its table entry (or 0 if it
|
||
is not in the hash table),
|
||
return an alternate expression for X as a register plus integer.
|
||
If none can be found, return 0. */
|
||
|
||
static rtx
|
||
use_related_value (rtx x, struct table_elt *elt)
|
||
{
|
||
struct table_elt *relt = 0;
|
||
struct table_elt *p, *q;
|
||
HOST_WIDE_INT offset;
|
||
|
||
/* First, is there anything related known?
|
||
If we have a table element, we can tell from that.
|
||
Otherwise, must look it up. */
|
||
|
||
if (elt != 0 && elt->related_value != 0)
|
||
relt = elt;
|
||
else if (elt == 0 && GET_CODE (x) == CONST)
|
||
{
|
||
rtx subexp = get_related_value (x);
|
||
if (subexp != 0)
|
||
relt = lookup (subexp,
|
||
SAFE_HASH (subexp, GET_MODE (subexp)),
|
||
GET_MODE (subexp));
|
||
}
|
||
|
||
if (relt == 0)
|
||
return 0;
|
||
|
||
/* Search all related table entries for one that has an
|
||
equivalent register. */
|
||
|
||
p = relt;
|
||
while (1)
|
||
{
|
||
/* This loop is strange in that it is executed in two different cases.
|
||
The first is when X is already in the table. Then it is searching
|
||
the RELATED_VALUE list of X's class (RELT). The second case is when
|
||
X is not in the table. Then RELT points to a class for the related
|
||
value.
|
||
|
||
Ensure that, whatever case we are in, that we ignore classes that have
|
||
the same value as X. */
|
||
|
||
if (rtx_equal_p (x, p->exp))
|
||
q = 0;
|
||
else
|
||
for (q = p->first_same_value; q; q = q->next_same_value)
|
||
if (REG_P (q->exp))
|
||
break;
|
||
|
||
if (q)
|
||
break;
|
||
|
||
p = p->related_value;
|
||
|
||
/* We went all the way around, so there is nothing to be found.
|
||
Alternatively, perhaps RELT was in the table for some other reason
|
||
and it has no related values recorded. */
|
||
if (p == relt || p == 0)
|
||
break;
|
||
}
|
||
|
||
if (q == 0)
|
||
return 0;
|
||
|
||
offset = (get_integer_term (x) - get_integer_term (p->exp));
|
||
/* Note: OFFSET may be 0 if P->xexp and X are related by commutativity. */
|
||
return plus_constant (q->exp, offset);
|
||
}
|
||
|
||
/* Hash a string. Just add its bytes up. */
|
||
static inline unsigned
|
||
hash_rtx_string (const char *ps)
|
||
{
|
||
unsigned hash = 0;
|
||
const unsigned char *p = (const unsigned char *) ps;
|
||
|
||
if (p)
|
||
while (*p)
|
||
hash += *p++;
|
||
|
||
return hash;
|
||
}
|
||
|
||
/* Hash an rtx. We are careful to make sure the value is never negative.
|
||
Equivalent registers hash identically.
|
||
MODE is used in hashing for CONST_INTs only;
|
||
otherwise the mode of X is used.
|
||
|
||
Store 1 in DO_NOT_RECORD_P if any subexpression is volatile.
|
||
|
||
If HASH_ARG_IN_MEMORY_P is not NULL, store 1 in it if X contains
|
||
a MEM rtx which does not have the RTX_UNCHANGING_P bit set.
|
||
|
||
Note that cse_insn knows that the hash code of a MEM expression
|
||
is just (int) MEM plus the hash code of the address. */
|
||
|
||
unsigned
|
||
hash_rtx (rtx x, enum machine_mode mode, int *do_not_record_p,
|
||
int *hash_arg_in_memory_p, bool have_reg_qty)
|
||
{
|
||
int i, j;
|
||
unsigned hash = 0;
|
||
enum rtx_code code;
|
||
const char *fmt;
|
||
|
||
/* Used to turn recursion into iteration. We can't rely on GCC's
|
||
tail-recursion elimination since we need to keep accumulating values
|
||
in HASH. */
|
||
repeat:
|
||
if (x == 0)
|
||
return hash;
|
||
|
||
code = GET_CODE (x);
|
||
switch (code)
|
||
{
|
||
case REG:
|
||
{
|
||
unsigned int regno = REGNO (x);
|
||
|
||
if (!reload_completed)
|
||
{
|
||
/* On some machines, we can't record any non-fixed hard register,
|
||
because extending its life will cause reload problems. We
|
||
consider ap, fp, sp, gp to be fixed for this purpose.
|
||
|
||
We also consider CCmode registers to be fixed for this purpose;
|
||
failure to do so leads to failure to simplify 0<100 type of
|
||
conditionals.
|
||
|
||
On all machines, we can't record any global registers.
|
||
Nor should we record any register that is in a small
|
||
class, as defined by CLASS_LIKELY_SPILLED_P. */
|
||
bool record;
|
||
|
||
if (regno >= FIRST_PSEUDO_REGISTER)
|
||
record = true;
|
||
else if (x == frame_pointer_rtx
|
||
|| x == hard_frame_pointer_rtx
|
||
|| x == arg_pointer_rtx
|
||
|| x == stack_pointer_rtx
|
||
|| x == pic_offset_table_rtx)
|
||
record = true;
|
||
else if (global_regs[regno])
|
||
record = false;
|
||
else if (fixed_regs[regno])
|
||
record = true;
|
||
else if (GET_MODE_CLASS (GET_MODE (x)) == MODE_CC)
|
||
record = true;
|
||
else if (SMALL_REGISTER_CLASSES)
|
||
record = false;
|
||
else if (CLASS_LIKELY_SPILLED_P (REGNO_REG_CLASS (regno)))
|
||
record = false;
|
||
else
|
||
record = true;
|
||
|
||
if (!record)
|
||
{
|
||
*do_not_record_p = 1;
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
hash += ((unsigned int) REG << 7);
|
||
hash += (have_reg_qty ? (unsigned) REG_QTY (regno) : regno);
|
||
return hash;
|
||
}
|
||
|
||
/* We handle SUBREG of a REG specially because the underlying
|
||
reg changes its hash value with every value change; we don't
|
||
want to have to forget unrelated subregs when one subreg changes. */
|
||
case SUBREG:
|
||
{
|
||
if (REG_P (SUBREG_REG (x)))
|
||
{
|
||
hash += (((unsigned int) SUBREG << 7)
|
||
+ REGNO (SUBREG_REG (x))
|
||
+ (SUBREG_BYTE (x) / UNITS_PER_WORD));
|
||
return hash;
|
||
}
|
||
break;
|
||
}
|
||
|
||
case CONST_INT:
|
||
hash += (((unsigned int) CONST_INT << 7) + (unsigned int) mode
|
||
+ (unsigned int) INTVAL (x));
|
||
return hash;
|
||
|
||
case CONST_DOUBLE:
|
||
/* This is like the general case, except that it only counts
|
||
the integers representing the constant. */
|
||
hash += (unsigned int) code + (unsigned int) GET_MODE (x);
|
||
if (GET_MODE (x) != VOIDmode)
|
||
hash += real_hash (CONST_DOUBLE_REAL_VALUE (x));
|
||
else
|
||
hash += ((unsigned int) CONST_DOUBLE_LOW (x)
|
||
+ (unsigned int) CONST_DOUBLE_HIGH (x));
|
||
return hash;
|
||
|
||
case CONST_VECTOR:
|
||
{
|
||
int units;
|
||
rtx elt;
|
||
|
||
units = CONST_VECTOR_NUNITS (x);
|
||
|
||
for (i = 0; i < units; ++i)
|
||
{
|
||
elt = CONST_VECTOR_ELT (x, i);
|
||
hash += hash_rtx (elt, GET_MODE (elt), do_not_record_p,
|
||
hash_arg_in_memory_p, have_reg_qty);
|
||
}
|
||
|
||
return hash;
|
||
}
|
||
|
||
/* Assume there is only one rtx object for any given label. */
|
||
case LABEL_REF:
|
||
/* We don't hash on the address of the CODE_LABEL to avoid bootstrap
|
||
differences and differences between each stage's debugging dumps. */
|
||
hash += (((unsigned int) LABEL_REF << 7)
|
||
+ CODE_LABEL_NUMBER (XEXP (x, 0)));
|
||
return hash;
|
||
|
||
case SYMBOL_REF:
|
||
{
|
||
/* Don't hash on the symbol's address to avoid bootstrap differences.
|
||
Different hash values may cause expressions to be recorded in
|
||
different orders and thus different registers to be used in the
|
||
final assembler. This also avoids differences in the dump files
|
||
between various stages. */
|
||
unsigned int h = 0;
|
||
const unsigned char *p = (const unsigned char *) XSTR (x, 0);
|
||
|
||
while (*p)
|
||
h += (h << 7) + *p++; /* ??? revisit */
|
||
|
||
hash += ((unsigned int) SYMBOL_REF << 7) + h;
|
||
return hash;
|
||
}
|
||
|
||
case MEM:
|
||
/* We don't record if marked volatile or if BLKmode since we don't
|
||
know the size of the move. */
|
||
if (MEM_VOLATILE_P (x) || GET_MODE (x) == BLKmode)
|
||
{
|
||
*do_not_record_p = 1;
|
||
return 0;
|
||
}
|
||
if (hash_arg_in_memory_p && !MEM_READONLY_P (x))
|
||
*hash_arg_in_memory_p = 1;
|
||
|
||
/* Now that we have already found this special case,
|
||
might as well speed it up as much as possible. */
|
||
hash += (unsigned) MEM;
|
||
x = XEXP (x, 0);
|
||
goto repeat;
|
||
|
||
case USE:
|
||
/* A USE that mentions non-volatile memory needs special
|
||
handling since the MEM may be BLKmode which normally
|
||
prevents an entry from being made. Pure calls are
|
||
marked by a USE which mentions BLKmode memory.
|
||
See calls.c:emit_call_1. */
|
||
if (MEM_P (XEXP (x, 0))
|
||
&& ! MEM_VOLATILE_P (XEXP (x, 0)))
|
||
{
|
||
hash += (unsigned) USE;
|
||
x = XEXP (x, 0);
|
||
|
||
if (hash_arg_in_memory_p && !MEM_READONLY_P (x))
|
||
*hash_arg_in_memory_p = 1;
|
||
|
||
/* Now that we have already found this special case,
|
||
might as well speed it up as much as possible. */
|
||
hash += (unsigned) MEM;
|
||
x = XEXP (x, 0);
|
||
goto repeat;
|
||
}
|
||
break;
|
||
|
||
case PRE_DEC:
|
||
case PRE_INC:
|
||
case POST_DEC:
|
||
case POST_INC:
|
||
case PRE_MODIFY:
|
||
case POST_MODIFY:
|
||
case PC:
|
||
case CC0:
|
||
case CALL:
|
||
case UNSPEC_VOLATILE:
|
||
*do_not_record_p = 1;
|
||
return 0;
|
||
|
||
case ASM_OPERANDS:
|
||
if (MEM_VOLATILE_P (x))
|
||
{
|
||
*do_not_record_p = 1;
|
||
return 0;
|
||
}
|
||
else
|
||
{
|
||
/* We don't want to take the filename and line into account. */
|
||
hash += (unsigned) code + (unsigned) GET_MODE (x)
|
||
+ hash_rtx_string (ASM_OPERANDS_TEMPLATE (x))
|
||
+ hash_rtx_string (ASM_OPERANDS_OUTPUT_CONSTRAINT (x))
|
||
+ (unsigned) ASM_OPERANDS_OUTPUT_IDX (x);
|
||
|
||
if (ASM_OPERANDS_INPUT_LENGTH (x))
|
||
{
|
||
for (i = 1; i < ASM_OPERANDS_INPUT_LENGTH (x); i++)
|
||
{
|
||
hash += (hash_rtx (ASM_OPERANDS_INPUT (x, i),
|
||
GET_MODE (ASM_OPERANDS_INPUT (x, i)),
|
||
do_not_record_p, hash_arg_in_memory_p,
|
||
have_reg_qty)
|
||
+ hash_rtx_string
|
||
(ASM_OPERANDS_INPUT_CONSTRAINT (x, i)));
|
||
}
|
||
|
||
hash += hash_rtx_string (ASM_OPERANDS_INPUT_CONSTRAINT (x, 0));
|
||
x = ASM_OPERANDS_INPUT (x, 0);
|
||
mode = GET_MODE (x);
|
||
goto repeat;
|
||
}
|
||
|
||
return hash;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
i = GET_RTX_LENGTH (code) - 1;
|
||
hash += (unsigned) code + (unsigned) GET_MODE (x);
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (; i >= 0; i--)
|
||
{
|
||
switch (fmt[i])
|
||
{
|
||
case 'e':
|
||
/* If we are about to do the last recursive call
|
||
needed at this level, change it into iteration.
|
||
This function is called enough to be worth it. */
|
||
if (i == 0)
|
||
{
|
||
x = XEXP (x, i);
|
||
goto repeat;
|
||
}
|
||
|
||
hash += hash_rtx (XEXP (x, i), 0, do_not_record_p,
|
||
hash_arg_in_memory_p, have_reg_qty);
|
||
break;
|
||
|
||
case 'E':
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
hash += hash_rtx (XVECEXP (x, i, j), 0, do_not_record_p,
|
||
hash_arg_in_memory_p, have_reg_qty);
|
||
break;
|
||
|
||
case 's':
|
||
hash += hash_rtx_string (XSTR (x, i));
|
||
break;
|
||
|
||
case 'i':
|
||
hash += (unsigned int) XINT (x, i);
|
||
break;
|
||
|
||
case '0': case 't':
|
||
/* Unused. */
|
||
break;
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
}
|
||
|
||
return hash;
|
||
}
|
||
|
||
/* Hash an rtx X for cse via hash_rtx.
|
||
Stores 1 in do_not_record if any subexpression is volatile.
|
||
Stores 1 in hash_arg_in_memory if X contains a mem rtx which
|
||
does not have the RTX_UNCHANGING_P bit set. */
|
||
|
||
static inline unsigned
|
||
canon_hash (rtx x, enum machine_mode mode)
|
||
{
|
||
return hash_rtx (x, mode, &do_not_record, &hash_arg_in_memory, true);
|
||
}
|
||
|
||
/* Like canon_hash but with no side effects, i.e. do_not_record
|
||
and hash_arg_in_memory are not changed. */
|
||
|
||
static inline unsigned
|
||
safe_hash (rtx x, enum machine_mode mode)
|
||
{
|
||
int dummy_do_not_record;
|
||
return hash_rtx (x, mode, &dummy_do_not_record, NULL, true);
|
||
}
|
||
|
||
/* Return 1 iff X and Y would canonicalize into the same thing,
|
||
without actually constructing the canonicalization of either one.
|
||
If VALIDATE is nonzero,
|
||
we assume X is an expression being processed from the rtl
|
||
and Y was found in the hash table. We check register refs
|
||
in Y for being marked as valid.
|
||
|
||
If FOR_GCSE is true, we compare X and Y for equivalence for GCSE. */
|
||
|
||
int
|
||
exp_equiv_p (rtx x, rtx y, int validate, bool for_gcse)
|
||
{
|
||
int i, j;
|
||
enum rtx_code code;
|
||
const char *fmt;
|
||
|
||
/* Note: it is incorrect to assume an expression is equivalent to itself
|
||
if VALIDATE is nonzero. */
|
||
if (x == y && !validate)
|
||
return 1;
|
||
|
||
if (x == 0 || y == 0)
|
||
return x == y;
|
||
|
||
code = GET_CODE (x);
|
||
if (code != GET_CODE (y))
|
||
return 0;
|
||
|
||
/* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
|
||
if (GET_MODE (x) != GET_MODE (y))
|
||
return 0;
|
||
|
||
switch (code)
|
||
{
|
||
case PC:
|
||
case CC0:
|
||
case CONST_INT:
|
||
case CONST_DOUBLE:
|
||
return x == y;
|
||
|
||
case LABEL_REF:
|
||
return XEXP (x, 0) == XEXP (y, 0);
|
||
|
||
case SYMBOL_REF:
|
||
return XSTR (x, 0) == XSTR (y, 0);
|
||
|
||
case REG:
|
||
if (for_gcse)
|
||
return REGNO (x) == REGNO (y);
|
||
else
|
||
{
|
||
unsigned int regno = REGNO (y);
|
||
unsigned int i;
|
||
unsigned int endregno
|
||
= regno + (regno >= FIRST_PSEUDO_REGISTER ? 1
|
||
: hard_regno_nregs[regno][GET_MODE (y)]);
|
||
|
||
/* If the quantities are not the same, the expressions are not
|
||
equivalent. If there are and we are not to validate, they
|
||
are equivalent. Otherwise, ensure all regs are up-to-date. */
|
||
|
||
if (REG_QTY (REGNO (x)) != REG_QTY (regno))
|
||
return 0;
|
||
|
||
if (! validate)
|
||
return 1;
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
if (REG_IN_TABLE (i) != REG_TICK (i))
|
||
return 0;
|
||
|
||
return 1;
|
||
}
|
||
|
||
case MEM:
|
||
if (for_gcse)
|
||
{
|
||
/* A volatile mem should not be considered equivalent to any
|
||
other. */
|
||
if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
|
||
return 0;
|
||
|
||
/* Can't merge two expressions in different alias sets, since we
|
||
can decide that the expression is transparent in a block when
|
||
it isn't, due to it being set with the different alias set.
|
||
|
||
Also, can't merge two expressions with different MEM_ATTRS.
|
||
They could e.g. be two different entities allocated into the
|
||
same space on the stack (see e.g. PR25130). In that case, the
|
||
MEM addresses can be the same, even though the two MEMs are
|
||
absolutely not equivalent.
|
||
|
||
But because really all MEM attributes should be the same for
|
||
equivalent MEMs, we just use the invariant that MEMs that have
|
||
the same attributes share the same mem_attrs data structure. */
|
||
if (MEM_ATTRS (x) != MEM_ATTRS (y))
|
||
return 0;
|
||
}
|
||
break;
|
||
|
||
/* For commutative operations, check both orders. */
|
||
case PLUS:
|
||
case MULT:
|
||
case AND:
|
||
case IOR:
|
||
case XOR:
|
||
case NE:
|
||
case EQ:
|
||
return ((exp_equiv_p (XEXP (x, 0), XEXP (y, 0),
|
||
validate, for_gcse)
|
||
&& exp_equiv_p (XEXP (x, 1), XEXP (y, 1),
|
||
validate, for_gcse))
|
||
|| (exp_equiv_p (XEXP (x, 0), XEXP (y, 1),
|
||
validate, for_gcse)
|
||
&& exp_equiv_p (XEXP (x, 1), XEXP (y, 0),
|
||
validate, for_gcse)));
|
||
|
||
case ASM_OPERANDS:
|
||
/* We don't use the generic code below because we want to
|
||
disregard filename and line numbers. */
|
||
|
||
/* A volatile asm isn't equivalent to any other. */
|
||
if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
|
||
return 0;
|
||
|
||
if (GET_MODE (x) != GET_MODE (y)
|
||
|| strcmp (ASM_OPERANDS_TEMPLATE (x), ASM_OPERANDS_TEMPLATE (y))
|
||
|| strcmp (ASM_OPERANDS_OUTPUT_CONSTRAINT (x),
|
||
ASM_OPERANDS_OUTPUT_CONSTRAINT (y))
|
||
|| ASM_OPERANDS_OUTPUT_IDX (x) != ASM_OPERANDS_OUTPUT_IDX (y)
|
||
|| ASM_OPERANDS_INPUT_LENGTH (x) != ASM_OPERANDS_INPUT_LENGTH (y))
|
||
return 0;
|
||
|
||
if (ASM_OPERANDS_INPUT_LENGTH (x))
|
||
{
|
||
for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--)
|
||
if (! exp_equiv_p (ASM_OPERANDS_INPUT (x, i),
|
||
ASM_OPERANDS_INPUT (y, i),
|
||
validate, for_gcse)
|
||
|| strcmp (ASM_OPERANDS_INPUT_CONSTRAINT (x, i),
|
||
ASM_OPERANDS_INPUT_CONSTRAINT (y, i)))
|
||
return 0;
|
||
}
|
||
|
||
return 1;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* Compare the elements. If any pair of corresponding elements
|
||
fail to match, return 0 for the whole thing. */
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
switch (fmt[i])
|
||
{
|
||
case 'e':
|
||
if (! exp_equiv_p (XEXP (x, i), XEXP (y, i),
|
||
validate, for_gcse))
|
||
return 0;
|
||
break;
|
||
|
||
case 'E':
|
||
if (XVECLEN (x, i) != XVECLEN (y, i))
|
||
return 0;
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
if (! exp_equiv_p (XVECEXP (x, i, j), XVECEXP (y, i, j),
|
||
validate, for_gcse))
|
||
return 0;
|
||
break;
|
||
|
||
case 's':
|
||
if (strcmp (XSTR (x, i), XSTR (y, i)))
|
||
return 0;
|
||
break;
|
||
|
||
case 'i':
|
||
if (XINT (x, i) != XINT (y, i))
|
||
return 0;
|
||
break;
|
||
|
||
case 'w':
|
||
if (XWINT (x, i) != XWINT (y, i))
|
||
return 0;
|
||
break;
|
||
|
||
case '0':
|
||
case 't':
|
||
break;
|
||
|
||
default:
|
||
gcc_unreachable ();
|
||
}
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Return 1 if X has a value that can vary even between two
|
||
executions of the program. 0 means X can be compared reliably
|
||
against certain constants or near-constants. */
|
||
|
||
static int
|
||
cse_rtx_varies_p (rtx x, int from_alias)
|
||
{
|
||
/* We need not check for X and the equivalence class being of the same
|
||
mode because if X is equivalent to a constant in some mode, it
|
||
doesn't vary in any mode. */
|
||
|
||
if (REG_P (x)
|
||
&& REGNO_QTY_VALID_P (REGNO (x)))
|
||
{
|
||
int x_q = REG_QTY (REGNO (x));
|
||
struct qty_table_elem *x_ent = &qty_table[x_q];
|
||
|
||
if (GET_MODE (x) == x_ent->mode
|
||
&& x_ent->const_rtx != NULL_RTX)
|
||
return 0;
|
||
}
|
||
|
||
if (GET_CODE (x) == PLUS
|
||
&& GET_CODE (XEXP (x, 1)) == CONST_INT
|
||
&& REG_P (XEXP (x, 0))
|
||
&& REGNO_QTY_VALID_P (REGNO (XEXP (x, 0))))
|
||
{
|
||
int x0_q = REG_QTY (REGNO (XEXP (x, 0)));
|
||
struct qty_table_elem *x0_ent = &qty_table[x0_q];
|
||
|
||
if ((GET_MODE (XEXP (x, 0)) == x0_ent->mode)
|
||
&& x0_ent->const_rtx != NULL_RTX)
|
||
return 0;
|
||
}
|
||
|
||
/* This can happen as the result of virtual register instantiation, if
|
||
the initial constant is too large to be a valid address. This gives
|
||
us a three instruction sequence, load large offset into a register,
|
||
load fp minus a constant into a register, then a MEM which is the
|
||
sum of the two `constant' registers. */
|
||
if (GET_CODE (x) == PLUS
|
||
&& REG_P (XEXP (x, 0))
|
||
&& REG_P (XEXP (x, 1))
|
||
&& REGNO_QTY_VALID_P (REGNO (XEXP (x, 0)))
|
||
&& REGNO_QTY_VALID_P (REGNO (XEXP (x, 1))))
|
||
{
|
||
int x0_q = REG_QTY (REGNO (XEXP (x, 0)));
|
||
int x1_q = REG_QTY (REGNO (XEXP (x, 1)));
|
||
struct qty_table_elem *x0_ent = &qty_table[x0_q];
|
||
struct qty_table_elem *x1_ent = &qty_table[x1_q];
|
||
|
||
if ((GET_MODE (XEXP (x, 0)) == x0_ent->mode)
|
||
&& x0_ent->const_rtx != NULL_RTX
|
||
&& (GET_MODE (XEXP (x, 1)) == x1_ent->mode)
|
||
&& x1_ent->const_rtx != NULL_RTX)
|
||
return 0;
|
||
}
|
||
|
||
return rtx_varies_p (x, from_alias);
|
||
}
|
||
|
||
/* Subroutine of canon_reg. Pass *XLOC through canon_reg, and validate
|
||
the result if necessary. INSN is as for canon_reg. */
|
||
|
||
static void
|
||
validate_canon_reg (rtx *xloc, rtx insn)
|
||
{
|
||
rtx new = canon_reg (*xloc, insn);
|
||
|
||
/* If replacing pseudo with hard reg or vice versa, ensure the
|
||
insn remains valid. Likewise if the insn has MATCH_DUPs. */
|
||
if (insn != 0 && new != 0)
|
||
validate_change (insn, xloc, new, 1);
|
||
else
|
||
*xloc = new;
|
||
}
|
||
|
||
/* Canonicalize an expression:
|
||
replace each register reference inside it
|
||
with the "oldest" equivalent register.
|
||
|
||
If INSN is nonzero validate_change is used to ensure that INSN remains valid
|
||
after we make our substitution. The calls are made with IN_GROUP nonzero
|
||
so apply_change_group must be called upon the outermost return from this
|
||
function (unless INSN is zero). The result of apply_change_group can
|
||
generally be discarded since the changes we are making are optional. */
|
||
|
||
static rtx
|
||
canon_reg (rtx x, rtx insn)
|
||
{
|
||
int i;
|
||
enum rtx_code code;
|
||
const char *fmt;
|
||
|
||
if (x == 0)
|
||
return x;
|
||
|
||
code = GET_CODE (x);
|
||
switch (code)
|
||
{
|
||
case PC:
|
||
case CC0:
|
||
case CONST:
|
||
case CONST_INT:
|
||
case CONST_DOUBLE:
|
||
case CONST_VECTOR:
|
||
case SYMBOL_REF:
|
||
case LABEL_REF:
|
||
case ADDR_VEC:
|
||
case ADDR_DIFF_VEC:
|
||
return x;
|
||
|
||
case REG:
|
||
{
|
||
int first;
|
||
int q;
|
||
struct qty_table_elem *ent;
|
||
|
||
/* Never replace a hard reg, because hard regs can appear
|
||
in more than one machine mode, and we must preserve the mode
|
||
of each occurrence. Also, some hard regs appear in
|
||
MEMs that are shared and mustn't be altered. Don't try to
|
||
replace any reg that maps to a reg of class NO_REGS. */
|
||
if (REGNO (x) < FIRST_PSEUDO_REGISTER
|
||
|| ! REGNO_QTY_VALID_P (REGNO (x)))
|
||
return x;
|
||
|
||
q = REG_QTY (REGNO (x));
|
||
ent = &qty_table[q];
|
||
first = ent->first_reg;
|
||
return (first >= FIRST_PSEUDO_REGISTER ? regno_reg_rtx[first]
|
||
: REGNO_REG_CLASS (first) == NO_REGS ? x
|
||
: gen_rtx_REG (ent->mode, first));
|
||
}
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
int j;
|
||
|
||
if (fmt[i] == 'e')
|
||
validate_canon_reg (&XEXP (x, i), insn);
|
||
else if (fmt[i] == 'E')
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
validate_canon_reg (&XVECEXP (x, i, j), insn);
|
||
}
|
||
|
||
return x;
|
||
}
|
||
|
||
/* LOC is a location within INSN that is an operand address (the contents of
|
||
a MEM). Find the best equivalent address to use that is valid for this
|
||
insn.
|
||
|
||
On most CISC machines, complicated address modes are costly, and rtx_cost
|
||
is a good approximation for that cost. However, most RISC machines have
|
||
only a few (usually only one) memory reference formats. If an address is
|
||
valid at all, it is often just as cheap as any other address. Hence, for
|
||
RISC machines, we use `address_cost' to compare the costs of various
|
||
addresses. For two addresses of equal cost, choose the one with the
|
||
highest `rtx_cost' value as that has the potential of eliminating the
|
||
most insns. For equal costs, we choose the first in the equivalence
|
||
class. Note that we ignore the fact that pseudo registers are cheaper than
|
||
hard registers here because we would also prefer the pseudo registers. */
|
||
|
||
static void
|
||
find_best_addr (rtx insn, rtx *loc, enum machine_mode mode)
|
||
{
|
||
struct table_elt *elt;
|
||
rtx addr = *loc;
|
||
struct table_elt *p;
|
||
int found_better = 1;
|
||
int save_do_not_record = do_not_record;
|
||
int save_hash_arg_in_memory = hash_arg_in_memory;
|
||
int addr_volatile;
|
||
int regno;
|
||
unsigned hash;
|
||
|
||
/* Do not try to replace constant addresses or addresses of local and
|
||
argument slots. These MEM expressions are made only once and inserted
|
||
in many instructions, as well as being used to control symbol table
|
||
output. It is not safe to clobber them.
|
||
|
||
There are some uncommon cases where the address is already in a register
|
||
for some reason, but we cannot take advantage of that because we have
|
||
no easy way to unshare the MEM. In addition, looking up all stack
|
||
addresses is costly. */
|
||
if ((GET_CODE (addr) == PLUS
|
||
&& REG_P (XEXP (addr, 0))
|
||
&& GET_CODE (XEXP (addr, 1)) == CONST_INT
|
||
&& (regno = REGNO (XEXP (addr, 0)),
|
||
regno == FRAME_POINTER_REGNUM || regno == HARD_FRAME_POINTER_REGNUM
|
||
|| regno == ARG_POINTER_REGNUM))
|
||
|| (REG_P (addr)
|
||
&& (regno = REGNO (addr), regno == FRAME_POINTER_REGNUM
|
||
|| regno == HARD_FRAME_POINTER_REGNUM
|
||
|| regno == ARG_POINTER_REGNUM))
|
||
|| CONSTANT_ADDRESS_P (addr))
|
||
return;
|
||
|
||
/* If this address is not simply a register, try to fold it. This will
|
||
sometimes simplify the expression. Many simplifications
|
||
will not be valid, but some, usually applying the associative rule, will
|
||
be valid and produce better code. */
|
||
if (!REG_P (addr))
|
||
{
|
||
rtx folded = canon_for_address (fold_rtx (addr, NULL_RTX));
|
||
|
||
if (folded != addr)
|
||
{
|
||
int addr_folded_cost = address_cost (folded, mode);
|
||
int addr_cost = address_cost (addr, mode);
|
||
|
||
if ((addr_folded_cost < addr_cost
|
||
|| (addr_folded_cost == addr_cost
|
||
/* ??? The rtx_cost comparison is left over from an older
|
||
version of this code. It is probably no longer helpful.*/
|
||
&& (rtx_cost (folded, MEM) > rtx_cost (addr, MEM)
|
||
|| approx_reg_cost (folded) < approx_reg_cost (addr))))
|
||
&& validate_change (insn, loc, folded, 0))
|
||
addr = folded;
|
||
}
|
||
}
|
||
|
||
/* If this address is not in the hash table, we can't look for equivalences
|
||
of the whole address. Also, ignore if volatile. */
|
||
|
||
do_not_record = 0;
|
||
hash = HASH (addr, Pmode);
|
||
addr_volatile = do_not_record;
|
||
do_not_record = save_do_not_record;
|
||
hash_arg_in_memory = save_hash_arg_in_memory;
|
||
|
||
if (addr_volatile)
|
||
return;
|
||
|
||
elt = lookup (addr, hash, Pmode);
|
||
|
||
if (elt)
|
||
{
|
||
/* We need to find the best (under the criteria documented above) entry
|
||
in the class that is valid. We use the `flag' field to indicate
|
||
choices that were invalid and iterate until we can't find a better
|
||
one that hasn't already been tried. */
|
||
|
||
for (p = elt->first_same_value; p; p = p->next_same_value)
|
||
p->flag = 0;
|
||
|
||
while (found_better)
|
||
{
|
||
int best_addr_cost = address_cost (*loc, mode);
|
||
int best_rtx_cost = (elt->cost + 1) >> 1;
|
||
int exp_cost;
|
||
struct table_elt *best_elt = elt;
|
||
|
||
found_better = 0;
|
||
for (p = elt->first_same_value; p; p = p->next_same_value)
|
||
if (! p->flag)
|
||
{
|
||
if ((REG_P (p->exp)
|
||
|| exp_equiv_p (p->exp, p->exp, 1, false))
|
||
&& ((exp_cost = address_cost (p->exp, mode)) < best_addr_cost
|
||
|| (exp_cost == best_addr_cost
|
||
&& ((p->cost + 1) >> 1) > best_rtx_cost)))
|
||
{
|
||
found_better = 1;
|
||
best_addr_cost = exp_cost;
|
||
best_rtx_cost = (p->cost + 1) >> 1;
|
||
best_elt = p;
|
||
}
|
||
}
|
||
|
||
if (found_better)
|
||
{
|
||
if (validate_change (insn, loc,
|
||
canon_reg (copy_rtx (best_elt->exp),
|
||
NULL_RTX), 0))
|
||
return;
|
||
else
|
||
best_elt->flag = 1;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If the address is a binary operation with the first operand a register
|
||
and the second a constant, do the same as above, but looking for
|
||
equivalences of the register. Then try to simplify before checking for
|
||
the best address to use. This catches a few cases: First is when we
|
||
have REG+const and the register is another REG+const. We can often merge
|
||
the constants and eliminate one insn and one register. It may also be
|
||
that a machine has a cheap REG+REG+const. Finally, this improves the
|
||
code on the Alpha for unaligned byte stores. */
|
||
|
||
if (flag_expensive_optimizations
|
||
&& ARITHMETIC_P (*loc)
|
||
&& REG_P (XEXP (*loc, 0)))
|
||
{
|
||
rtx op1 = XEXP (*loc, 1);
|
||
|
||
do_not_record = 0;
|
||
hash = HASH (XEXP (*loc, 0), Pmode);
|
||
do_not_record = save_do_not_record;
|
||
hash_arg_in_memory = save_hash_arg_in_memory;
|
||
|
||
elt = lookup (XEXP (*loc, 0), hash, Pmode);
|
||
if (elt == 0)
|
||
return;
|
||
|
||
/* We need to find the best (under the criteria documented above) entry
|
||
in the class that is valid. We use the `flag' field to indicate
|
||
choices that were invalid and iterate until we can't find a better
|
||
one that hasn't already been tried. */
|
||
|
||
for (p = elt->first_same_value; p; p = p->next_same_value)
|
||
p->flag = 0;
|
||
|
||
while (found_better)
|
||
{
|
||
int best_addr_cost = address_cost (*loc, mode);
|
||
int best_rtx_cost = (COST (*loc) + 1) >> 1;
|
||
struct table_elt *best_elt = elt;
|
||
rtx best_rtx = *loc;
|
||
int count;
|
||
|
||
/* This is at worst case an O(n^2) algorithm, so limit our search
|
||
to the first 32 elements on the list. This avoids trouble
|
||
compiling code with very long basic blocks that can easily
|
||
call simplify_gen_binary so many times that we run out of
|
||
memory. */
|
||
|
||
found_better = 0;
|
||
for (p = elt->first_same_value, count = 0;
|
||
p && count < 32;
|
||
p = p->next_same_value, count++)
|
||
if (! p->flag
|
||
&& (REG_P (p->exp)
|
||
|| (GET_CODE (p->exp) != EXPR_LIST
|
||
&& exp_equiv_p (p->exp, p->exp, 1, false))))
|
||
|
||
{
|
||
rtx new = simplify_gen_binary (GET_CODE (*loc), Pmode,
|
||
p->exp, op1);
|
||
int new_cost;
|
||
|
||
/* Get the canonical version of the address so we can accept
|
||
more. */
|
||
new = canon_for_address (new);
|
||
|
||
new_cost = address_cost (new, mode);
|
||
|
||
if (new_cost < best_addr_cost
|
||
|| (new_cost == best_addr_cost
|
||
&& (COST (new) + 1) >> 1 > best_rtx_cost))
|
||
{
|
||
found_better = 1;
|
||
best_addr_cost = new_cost;
|
||
best_rtx_cost = (COST (new) + 1) >> 1;
|
||
best_elt = p;
|
||
best_rtx = new;
|
||
}
|
||
}
|
||
|
||
if (found_better)
|
||
{
|
||
if (validate_change (insn, loc,
|
||
canon_reg (copy_rtx (best_rtx),
|
||
NULL_RTX), 0))
|
||
return;
|
||
else
|
||
best_elt->flag = 1;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Given an operation (CODE, *PARG1, *PARG2), where code is a comparison
|
||
operation (EQ, NE, GT, etc.), follow it back through the hash table and
|
||
what values are being compared.
|
||
|
||
*PARG1 and *PARG2 are updated to contain the rtx representing the values
|
||
actually being compared. For example, if *PARG1 was (cc0) and *PARG2
|
||
was (const_int 0), *PARG1 and *PARG2 will be set to the objects that were
|
||
compared to produce cc0.
|
||
|
||
The return value is the comparison operator and is either the code of
|
||
A or the code corresponding to the inverse of the comparison. */
|
||
|
||
static enum rtx_code
|
||
find_comparison_args (enum rtx_code code, rtx *parg1, rtx *parg2,
|
||
enum machine_mode *pmode1, enum machine_mode *pmode2)
|
||
{
|
||
rtx arg1, arg2;
|
||
|
||
arg1 = *parg1, arg2 = *parg2;
|
||
|
||
/* If ARG2 is const0_rtx, see what ARG1 is equivalent to. */
|
||
|
||
while (arg2 == CONST0_RTX (GET_MODE (arg1)))
|
||
{
|
||
/* Set nonzero when we find something of interest. */
|
||
rtx x = 0;
|
||
int reverse_code = 0;
|
||
struct table_elt *p = 0;
|
||
|
||
/* If arg1 is a COMPARE, extract the comparison arguments from it.
|
||
On machines with CC0, this is the only case that can occur, since
|
||
fold_rtx will return the COMPARE or item being compared with zero
|
||
when given CC0. */
|
||
|
||
if (GET_CODE (arg1) == COMPARE && arg2 == const0_rtx)
|
||
x = arg1;
|
||
|
||
/* If ARG1 is a comparison operator and CODE is testing for
|
||
STORE_FLAG_VALUE, get the inner arguments. */
|
||
|
||
else if (COMPARISON_P (arg1))
|
||
{
|
||
#ifdef FLOAT_STORE_FLAG_VALUE
|
||
REAL_VALUE_TYPE fsfv;
|
||
#endif
|
||
|
||
if (code == NE
|
||
|| (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_INT
|
||
&& code == LT && STORE_FLAG_VALUE == -1)
|
||
#ifdef FLOAT_STORE_FLAG_VALUE
|
||
|| (SCALAR_FLOAT_MODE_P (GET_MODE (arg1))
|
||
&& (fsfv = FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)),
|
||
REAL_VALUE_NEGATIVE (fsfv)))
|
||
#endif
|
||
)
|
||
x = arg1;
|
||
else if (code == EQ
|
||
|| (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_INT
|
||
&& code == GE && STORE_FLAG_VALUE == -1)
|
||
#ifdef FLOAT_STORE_FLAG_VALUE
|
||
|| (SCALAR_FLOAT_MODE_P (GET_MODE (arg1))
|
||
&& (fsfv = FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)),
|
||
REAL_VALUE_NEGATIVE (fsfv)))
|
||
#endif
|
||
)
|
||
x = arg1, reverse_code = 1;
|
||
}
|
||
|
||
/* ??? We could also check for
|
||
|
||
(ne (and (eq (...) (const_int 1))) (const_int 0))
|
||
|
||
and related forms, but let's wait until we see them occurring. */
|
||
|
||
if (x == 0)
|
||
/* Look up ARG1 in the hash table and see if it has an equivalence
|
||
that lets us see what is being compared. */
|
||
p = lookup (arg1, SAFE_HASH (arg1, GET_MODE (arg1)), GET_MODE (arg1));
|
||
if (p)
|
||
{
|
||
p = p->first_same_value;
|
||
|
||
/* If what we compare is already known to be constant, that is as
|
||
good as it gets.
|
||
We need to break the loop in this case, because otherwise we
|
||
can have an infinite loop when looking at a reg that is known
|
||
to be a constant which is the same as a comparison of a reg
|
||
against zero which appears later in the insn stream, which in
|
||
turn is constant and the same as the comparison of the first reg
|
||
against zero... */
|
||
if (p->is_const)
|
||
break;
|
||
}
|
||
|
||
for (; p; p = p->next_same_value)
|
||
{
|
||
enum machine_mode inner_mode = GET_MODE (p->exp);
|
||
#ifdef FLOAT_STORE_FLAG_VALUE
|
||
REAL_VALUE_TYPE fsfv;
|
||
#endif
|
||
|
||
/* If the entry isn't valid, skip it. */
|
||
if (! exp_equiv_p (p->exp, p->exp, 1, false))
|
||
continue;
|
||
|
||
if (GET_CODE (p->exp) == COMPARE
|
||
/* Another possibility is that this machine has a compare insn
|
||
that includes the comparison code. In that case, ARG1 would
|
||
be equivalent to a comparison operation that would set ARG1 to
|
||
either STORE_FLAG_VALUE or zero. If this is an NE operation,
|
||
ORIG_CODE is the actual comparison being done; if it is an EQ,
|
||
we must reverse ORIG_CODE. On machine with a negative value
|
||
for STORE_FLAG_VALUE, also look at LT and GE operations. */
|
||
|| ((code == NE
|
||
|| (code == LT
|
||
&& GET_MODE_CLASS (inner_mode) == MODE_INT
|
||
&& (GET_MODE_BITSIZE (inner_mode)
|
||
<= HOST_BITS_PER_WIDE_INT)
|
||
&& (STORE_FLAG_VALUE
|
||
& ((HOST_WIDE_INT) 1
|
||
<< (GET_MODE_BITSIZE (inner_mode) - 1))))
|
||
#ifdef FLOAT_STORE_FLAG_VALUE
|
||
|| (code == LT
|
||
&& SCALAR_FLOAT_MODE_P (inner_mode)
|
||
&& (fsfv = FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)),
|
||
REAL_VALUE_NEGATIVE (fsfv)))
|
||
#endif
|
||
)
|
||
&& COMPARISON_P (p->exp)))
|
||
{
|
||
x = p->exp;
|
||
break;
|
||
}
|
||
else if ((code == EQ
|
||
|| (code == GE
|
||
&& GET_MODE_CLASS (inner_mode) == MODE_INT
|
||
&& (GET_MODE_BITSIZE (inner_mode)
|
||
<= HOST_BITS_PER_WIDE_INT)
|
||
&& (STORE_FLAG_VALUE
|
||
& ((HOST_WIDE_INT) 1
|
||
<< (GET_MODE_BITSIZE (inner_mode) - 1))))
|
||
#ifdef FLOAT_STORE_FLAG_VALUE
|
||
|| (code == GE
|
||
&& SCALAR_FLOAT_MODE_P (inner_mode)
|
||
&& (fsfv = FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)),
|
||
REAL_VALUE_NEGATIVE (fsfv)))
|
||
#endif
|
||
)
|
||
&& COMPARISON_P (p->exp))
|
||
{
|
||
reverse_code = 1;
|
||
x = p->exp;
|
||
break;
|
||
}
|
||
|
||
/* If this non-trapping address, e.g. fp + constant, the
|
||
equivalent is a better operand since it may let us predict
|
||
the value of the comparison. */
|
||
else if (!rtx_addr_can_trap_p (p->exp))
|
||
{
|
||
arg1 = p->exp;
|
||
continue;
|
||
}
|
||
}
|
||
|
||
/* If we didn't find a useful equivalence for ARG1, we are done.
|
||
Otherwise, set up for the next iteration. */
|
||
if (x == 0)
|
||
break;
|
||
|
||
/* If we need to reverse the comparison, make sure that that is
|
||
possible -- we can't necessarily infer the value of GE from LT
|
||
with floating-point operands. */
|
||
if (reverse_code)
|
||
{
|
||
enum rtx_code reversed = reversed_comparison_code (x, NULL_RTX);
|
||
if (reversed == UNKNOWN)
|
||
break;
|
||
else
|
||
code = reversed;
|
||
}
|
||
else if (COMPARISON_P (x))
|
||
code = GET_CODE (x);
|
||
arg1 = XEXP (x, 0), arg2 = XEXP (x, 1);
|
||
}
|
||
|
||
/* Return our results. Return the modes from before fold_rtx
|
||
because fold_rtx might produce const_int, and then it's too late. */
|
||
*pmode1 = GET_MODE (arg1), *pmode2 = GET_MODE (arg2);
|
||
*parg1 = fold_rtx (arg1, 0), *parg2 = fold_rtx (arg2, 0);
|
||
|
||
return code;
|
||
}
|
||
|
||
/* Fold SUBREG. */
|
||
|
||
static rtx
|
||
fold_rtx_subreg (rtx x, rtx insn)
|
||
{
|
||
enum machine_mode mode = GET_MODE (x);
|
||
rtx folded_arg0;
|
||
rtx const_arg0;
|
||
rtx new;
|
||
|
||
/* See if we previously assigned a constant value to this SUBREG. */
|
||
if ((new = lookup_as_function (x, CONST_INT)) != 0
|
||
|| (new = lookup_as_function (x, CONST_DOUBLE)) != 0)
|
||
return new;
|
||
|
||
/* If this is a paradoxical SUBREG, we have no idea what value the
|
||
extra bits would have. However, if the operand is equivalent to
|
||
a SUBREG whose operand is the same as our mode, and all the modes
|
||
are within a word, we can just use the inner operand because
|
||
these SUBREGs just say how to treat the register.
|
||
|
||
Similarly if we find an integer constant. */
|
||
|
||
if (GET_MODE_SIZE (mode) > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
|
||
{
|
||
enum machine_mode imode = GET_MODE (SUBREG_REG (x));
|
||
struct table_elt *elt;
|
||
|
||
if (GET_MODE_SIZE (mode) <= UNITS_PER_WORD
|
||
&& GET_MODE_SIZE (imode) <= UNITS_PER_WORD
|
||
&& (elt = lookup (SUBREG_REG (x), HASH (SUBREG_REG (x), imode),
|
||
imode)) != 0)
|
||
for (elt = elt->first_same_value; elt; elt = elt->next_same_value)
|
||
{
|
||
if (CONSTANT_P (elt->exp)
|
||
&& GET_MODE (elt->exp) == VOIDmode)
|
||
return elt->exp;
|
||
|
||
if (GET_CODE (elt->exp) == SUBREG
|
||
&& GET_MODE (SUBREG_REG (elt->exp)) == mode
|
||
&& exp_equiv_p (elt->exp, elt->exp, 1, false))
|
||
return copy_rtx (SUBREG_REG (elt->exp));
|
||
}
|
||
|
||
return x;
|
||
}
|
||
|
||
/* Fold SUBREG_REG. If it changed, see if we can simplify the
|
||
SUBREG. We might be able to if the SUBREG is extracting a single
|
||
word in an integral mode or extracting the low part. */
|
||
|
||
folded_arg0 = fold_rtx (SUBREG_REG (x), insn);
|
||
const_arg0 = equiv_constant (folded_arg0);
|
||
if (const_arg0)
|
||
folded_arg0 = const_arg0;
|
||
|
||
if (folded_arg0 != SUBREG_REG (x))
|
||
{
|
||
new = simplify_subreg (mode, folded_arg0,
|
||
GET_MODE (SUBREG_REG (x)), SUBREG_BYTE (x));
|
||
if (new)
|
||
return new;
|
||
}
|
||
|
||
if (REG_P (folded_arg0)
|
||
&& GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (folded_arg0)))
|
||
{
|
||
struct table_elt *elt;
|
||
|
||
elt = lookup (folded_arg0,
|
||
HASH (folded_arg0, GET_MODE (folded_arg0)),
|
||
GET_MODE (folded_arg0));
|
||
|
||
if (elt)
|
||
elt = elt->first_same_value;
|
||
|
||
if (subreg_lowpart_p (x))
|
||
/* If this is a narrowing SUBREG and our operand is a REG, see
|
||
if we can find an equivalence for REG that is an arithmetic
|
||
operation in a wider mode where both operands are
|
||
paradoxical SUBREGs from objects of our result mode. In
|
||
that case, we couldn-t report an equivalent value for that
|
||
operation, since we don't know what the extra bits will be.
|
||
But we can find an equivalence for this SUBREG by folding
|
||
that operation in the narrow mode. This allows us to fold
|
||
arithmetic in narrow modes when the machine only supports
|
||
word-sized arithmetic.
|
||
|
||
Also look for a case where we have a SUBREG whose operand
|
||
is the same as our result. If both modes are smaller than
|
||
a word, we are simply interpreting a register in different
|
||
modes and we can use the inner value. */
|
||
|
||
for (; elt; elt = elt->next_same_value)
|
||
{
|
||
enum rtx_code eltcode = GET_CODE (elt->exp);
|
||
|
||
/* Just check for unary and binary operations. */
|
||
if (UNARY_P (elt->exp)
|
||
&& eltcode != SIGN_EXTEND
|
||
&& eltcode != ZERO_EXTEND
|
||
&& GET_CODE (XEXP (elt->exp, 0)) == SUBREG
|
||
&& GET_MODE (SUBREG_REG (XEXP (elt->exp, 0))) == mode
|
||
&& (GET_MODE_CLASS (mode)
|
||
== GET_MODE_CLASS (GET_MODE (XEXP (elt->exp, 0)))))
|
||
{
|
||
rtx op0 = SUBREG_REG (XEXP (elt->exp, 0));
|
||
|
||
if (!REG_P (op0) && ! CONSTANT_P (op0))
|
||
op0 = fold_rtx (op0, NULL_RTX);
|
||
|
||
op0 = equiv_constant (op0);
|
||
if (op0)
|
||
new = simplify_unary_operation (GET_CODE (elt->exp), mode,
|
||
op0, mode);
|
||
}
|
||
else if (ARITHMETIC_P (elt->exp)
|
||
&& eltcode != DIV && eltcode != MOD
|
||
&& eltcode != UDIV && eltcode != UMOD
|
||
&& eltcode != ASHIFTRT && eltcode != LSHIFTRT
|
||
&& eltcode != ROTATE && eltcode != ROTATERT
|
||
&& ((GET_CODE (XEXP (elt->exp, 0)) == SUBREG
|
||
&& (GET_MODE (SUBREG_REG (XEXP (elt->exp, 0)))
|
||
== mode))
|
||
|| CONSTANT_P (XEXP (elt->exp, 0)))
|
||
&& ((GET_CODE (XEXP (elt->exp, 1)) == SUBREG
|
||
&& (GET_MODE (SUBREG_REG (XEXP (elt->exp, 1)))
|
||
== mode))
|
||
|| CONSTANT_P (XEXP (elt->exp, 1))))
|
||
{
|
||
rtx op0 = gen_lowpart_common (mode, XEXP (elt->exp, 0));
|
||
rtx op1 = gen_lowpart_common (mode, XEXP (elt->exp, 1));
|
||
|
||
if (op0 && !REG_P (op0) && ! CONSTANT_P (op0))
|
||
op0 = fold_rtx (op0, NULL_RTX);
|
||
|
||
if (op0)
|
||
op0 = equiv_constant (op0);
|
||
|
||
if (op1 && !REG_P (op1) && ! CONSTANT_P (op1))
|
||
op1 = fold_rtx (op1, NULL_RTX);
|
||
|
||
if (op1)
|
||
op1 = equiv_constant (op1);
|
||
|
||
/* If we are looking for the low SImode part of
|
||
(ashift:DI c (const_int 32)), it doesn't work to
|
||
compute that in SImode, because a 32-bit shift in
|
||
SImode is unpredictable. We know the value is
|
||
0. */
|
||
if (op0 && op1
|
||
&& GET_CODE (elt->exp) == ASHIFT
|
||
&& GET_CODE (op1) == CONST_INT
|
||
&& INTVAL (op1) >= GET_MODE_BITSIZE (mode))
|
||
{
|
||
if (INTVAL (op1)
|
||
< GET_MODE_BITSIZE (GET_MODE (elt->exp)))
|
||
/* If the count fits in the inner mode's width,
|
||
but exceeds the outer mode's width, the value
|
||
will get truncated to 0 by the subreg. */
|
||
new = CONST0_RTX (mode);
|
||
else
|
||
/* If the count exceeds even the inner mode's width,
|
||
don't fold this expression. */
|
||
new = 0;
|
||
}
|
||
else if (op0 && op1)
|
||
new = simplify_binary_operation (GET_CODE (elt->exp),
|
||
mode, op0, op1);
|
||
}
|
||
|
||
else if (GET_CODE (elt->exp) == SUBREG
|
||
&& GET_MODE (SUBREG_REG (elt->exp)) == mode
|
||
&& (GET_MODE_SIZE (GET_MODE (folded_arg0))
|
||
<= UNITS_PER_WORD)
|
||
&& exp_equiv_p (elt->exp, elt->exp, 1, false))
|
||
new = copy_rtx (SUBREG_REG (elt->exp));
|
||
|
||
if (new)
|
||
return new;
|
||
}
|
||
else
|
||
/* A SUBREG resulting from a zero extension may fold to zero
|
||
if it extracts higher bits than the ZERO_EXTEND's source
|
||
bits. FIXME: if combine tried to, er, combine these
|
||
instructions, this transformation may be moved to
|
||
simplify_subreg. */
|
||
for (; elt; elt = elt->next_same_value)
|
||
{
|
||
if (GET_CODE (elt->exp) == ZERO_EXTEND
|
||
&& subreg_lsb (x)
|
||
>= GET_MODE_BITSIZE (GET_MODE (XEXP (elt->exp, 0))))
|
||
return CONST0_RTX (mode);
|
||
}
|
||
}
|
||
|
||
return x;
|
||
}
|
||
|
||
/* Fold MEM. Not to be called directly, see fold_rtx_mem instead. */
|
||
|
||
static rtx
|
||
fold_rtx_mem_1 (rtx x, rtx insn)
|
||
{
|
||
enum machine_mode mode = GET_MODE (x);
|
||
rtx new;
|
||
|
||
/* If we are not actually processing an insn, don't try to find the
|
||
best address. Not only don't we care, but we could modify the
|
||
MEM in an invalid way since we have no insn to validate
|
||
against. */
|
||
if (insn != 0)
|
||
find_best_addr (insn, &XEXP (x, 0), mode);
|
||
|
||
{
|
||
/* Even if we don't fold in the insn itself, we can safely do so
|
||
here, in hopes of getting a constant. */
|
||
rtx addr = fold_rtx (XEXP (x, 0), NULL_RTX);
|
||
rtx base = 0;
|
||
HOST_WIDE_INT offset = 0;
|
||
|
||
if (REG_P (addr)
|
||
&& REGNO_QTY_VALID_P (REGNO (addr)))
|
||
{
|
||
int addr_q = REG_QTY (REGNO (addr));
|
||
struct qty_table_elem *addr_ent = &qty_table[addr_q];
|
||
|
||
if (GET_MODE (addr) == addr_ent->mode
|
||
&& addr_ent->const_rtx != NULL_RTX)
|
||
addr = addr_ent->const_rtx;
|
||
}
|
||
|
||
/* Call target hook to avoid the effects of -fpic etc.... */
|
||
addr = targetm.delegitimize_address (addr);
|
||
|
||
/* If address is constant, split it into a base and integer
|
||
offset. */
|
||
if (GET_CODE (addr) == SYMBOL_REF || GET_CODE (addr) == LABEL_REF)
|
||
base = addr;
|
||
else if (GET_CODE (addr) == CONST && GET_CODE (XEXP (addr, 0)) == PLUS
|
||
&& GET_CODE (XEXP (XEXP (addr, 0), 1)) == CONST_INT)
|
||
{
|
||
base = XEXP (XEXP (addr, 0), 0);
|
||
offset = INTVAL (XEXP (XEXP (addr, 0), 1));
|
||
}
|
||
else if (GET_CODE (addr) == LO_SUM
|
||
&& GET_CODE (XEXP (addr, 1)) == SYMBOL_REF)
|
||
base = XEXP (addr, 1);
|
||
|
||
/* If this is a constant pool reference, we can fold it into its
|
||
constant to allow better value tracking. */
|
||
if (base && GET_CODE (base) == SYMBOL_REF
|
||
&& CONSTANT_POOL_ADDRESS_P (base))
|
||
{
|
||
rtx constant = get_pool_constant (base);
|
||
enum machine_mode const_mode = get_pool_mode (base);
|
||
rtx new;
|
||
|
||
if (CONSTANT_P (constant) && GET_CODE (constant) != CONST_INT)
|
||
{
|
||
constant_pool_entries_cost = COST (constant);
|
||
constant_pool_entries_regcost = approx_reg_cost (constant);
|
||
}
|
||
|
||
/* If we are loading the full constant, we have an
|
||
equivalence. */
|
||
if (offset == 0 && mode == const_mode)
|
||
return constant;
|
||
|
||
/* If this actually isn't a constant (weird!), we can't do
|
||
anything. Otherwise, handle the two most common cases:
|
||
extracting a word from a multi-word constant, and
|
||
extracting the low-order bits. Other cases don't seem
|
||
common enough to worry about. */
|
||
if (! CONSTANT_P (constant))
|
||
return x;
|
||
|
||
if (GET_MODE_CLASS (mode) == MODE_INT
|
||
&& GET_MODE_SIZE (mode) == UNITS_PER_WORD
|
||
&& offset % UNITS_PER_WORD == 0
|
||
&& (new = operand_subword (constant,
|
||
offset / UNITS_PER_WORD,
|
||
0, const_mode)) != 0)
|
||
return new;
|
||
|
||
if (((BYTES_BIG_ENDIAN
|
||
&& offset == GET_MODE_SIZE (GET_MODE (constant)) - 1)
|
||
|| (! BYTES_BIG_ENDIAN && offset == 0))
|
||
&& (new = gen_lowpart (mode, constant)) != 0)
|
||
return new;
|
||
}
|
||
|
||
/* If this is a reference to a label at a known position in a jump
|
||
table, we also know its value. */
|
||
if (base && GET_CODE (base) == LABEL_REF)
|
||
{
|
||
rtx label = XEXP (base, 0);
|
||
rtx table_insn = NEXT_INSN (label);
|
||
|
||
if (table_insn && JUMP_P (table_insn)
|
||
&& GET_CODE (PATTERN (table_insn)) == ADDR_VEC)
|
||
{
|
||
rtx table = PATTERN (table_insn);
|
||
|
||
if (offset >= 0
|
||
&& (offset / GET_MODE_SIZE (GET_MODE (table))
|
||
< XVECLEN (table, 0)))
|
||
{
|
||
rtx label = XVECEXP
|
||
(table, 0, offset / GET_MODE_SIZE (GET_MODE (table)));
|
||
rtx set;
|
||
|
||
/* If we have an insn that loads the label from the
|
||
jumptable into a reg, we don't want to set the reg
|
||
to the label, because this may cause a reference to
|
||
the label to remain after the label is removed in
|
||
some very obscure cases (PR middle-end/18628). */
|
||
if (!insn)
|
||
return label;
|
||
|
||
set = single_set (insn);
|
||
|
||
if (! set || SET_SRC (set) != x)
|
||
return x;
|
||
|
||
/* If it's a jump, it's safe to reference the label. */
|
||
if (SET_DEST (set) == pc_rtx)
|
||
return label;
|
||
|
||
return x;
|
||
}
|
||
}
|
||
if (table_insn && JUMP_P (table_insn)
|
||
&& GET_CODE (PATTERN (table_insn)) == ADDR_DIFF_VEC)
|
||
{
|
||
rtx table = PATTERN (table_insn);
|
||
|
||
if (offset >= 0
|
||
&& (offset / GET_MODE_SIZE (GET_MODE (table))
|
||
< XVECLEN (table, 1)))
|
||
{
|
||
offset /= GET_MODE_SIZE (GET_MODE (table));
|
||
new = gen_rtx_MINUS (Pmode, XVECEXP (table, 1, offset),
|
||
XEXP (table, 0));
|
||
|
||
if (GET_MODE (table) != Pmode)
|
||
new = gen_rtx_TRUNCATE (GET_MODE (table), new);
|
||
|
||
/* Indicate this is a constant. This isn't a valid
|
||
form of CONST, but it will only be used to fold the
|
||
next insns and then discarded, so it should be
|
||
safe.
|
||
|
||
Note this expression must be explicitly discarded,
|
||
by cse_insn, else it may end up in a REG_EQUAL note
|
||
and "escape" to cause problems elsewhere. */
|
||
return gen_rtx_CONST (GET_MODE (new), new);
|
||
}
|
||
}
|
||
}
|
||
|
||
return x;
|
||
}
|
||
}
|
||
|
||
/* Fold MEM. */
|
||
|
||
static rtx
|
||
fold_rtx_mem (rtx x, rtx insn)
|
||
{
|
||
/* To avoid infinite oscillations between fold_rtx and fold_rtx_mem,
|
||
refuse to allow recursion of the latter past n levels. This can
|
||
happen because fold_rtx_mem will try to fold the address of the
|
||
memory reference it is passed, i.e. conceptually throwing away
|
||
the MEM and reinjecting the bare address into fold_rtx. As a
|
||
result, patterns like
|
||
|
||
set (reg1)
|
||
(plus (reg)
|
||
(mem (plus (reg2) (const_int))))
|
||
|
||
set (reg2)
|
||
(plus (reg)
|
||
(mem (plus (reg1) (const_int))))
|
||
|
||
will defeat any "first-order" short-circuit put in either
|
||
function to prevent these infinite oscillations.
|
||
|
||
The heuristics for determining n is as follows: since each time
|
||
it is invoked fold_rtx_mem throws away a MEM, and since MEMs
|
||
are generically not nested, we assume that each invocation of
|
||
fold_rtx_mem corresponds to a new "top-level" operand, i.e.
|
||
the source or the destination of a SET. So fold_rtx_mem is
|
||
bound to stop or cycle before n recursions, n being the number
|
||
of expressions recorded in the hash table. We also leave some
|
||
play to account for the initial steps. */
|
||
|
||
static unsigned int depth;
|
||
rtx ret;
|
||
|
||
if (depth > 3 + table_size)
|
||
return x;
|
||
|
||
depth++;
|
||
ret = fold_rtx_mem_1 (x, insn);
|
||
depth--;
|
||
|
||
return ret;
|
||
}
|
||
|
||
/* If X is a nontrivial arithmetic operation on an argument
|
||
for which a constant value can be determined, return
|
||
the result of operating on that value, as a constant.
|
||
Otherwise, return X, possibly with one or more operands
|
||
modified by recursive calls to this function.
|
||
|
||
If X is a register whose contents are known, we do NOT
|
||
return those contents here. equiv_constant is called to
|
||
perform that task.
|
||
|
||
INSN is the insn that we may be modifying. If it is 0, make a copy
|
||
of X before modifying it. */
|
||
|
||
static rtx
|
||
fold_rtx (rtx x, rtx insn)
|
||
{
|
||
enum rtx_code code;
|
||
enum machine_mode mode;
|
||
const char *fmt;
|
||
int i;
|
||
rtx new = 0;
|
||
int copied = 0;
|
||
int must_swap = 0;
|
||
|
||
/* Folded equivalents of first two operands of X. */
|
||
rtx folded_arg0;
|
||
rtx folded_arg1;
|
||
|
||
/* Constant equivalents of first three operands of X;
|
||
0 when no such equivalent is known. */
|
||
rtx const_arg0;
|
||
rtx const_arg1;
|
||
rtx const_arg2;
|
||
|
||
/* The mode of the first operand of X. We need this for sign and zero
|
||
extends. */
|
||
enum machine_mode mode_arg0;
|
||
|
||
if (x == 0)
|
||
return x;
|
||
|
||
mode = GET_MODE (x);
|
||
code = GET_CODE (x);
|
||
switch (code)
|
||
{
|
||
case CONST:
|
||
case CONST_INT:
|
||
case CONST_DOUBLE:
|
||
case CONST_VECTOR:
|
||
case SYMBOL_REF:
|
||
case LABEL_REF:
|
||
case REG:
|
||
case PC:
|
||
/* No use simplifying an EXPR_LIST
|
||
since they are used only for lists of args
|
||
in a function call's REG_EQUAL note. */
|
||
case EXPR_LIST:
|
||
return x;
|
||
|
||
#ifdef HAVE_cc0
|
||
case CC0:
|
||
return prev_insn_cc0;
|
||
#endif
|
||
|
||
case SUBREG:
|
||
return fold_rtx_subreg (x, insn);
|
||
|
||
case NOT:
|
||
case NEG:
|
||
/* If we have (NOT Y), see if Y is known to be (NOT Z).
|
||
If so, (NOT Y) simplifies to Z. Similarly for NEG. */
|
||
new = lookup_as_function (XEXP (x, 0), code);
|
||
if (new)
|
||
return fold_rtx (copy_rtx (XEXP (new, 0)), insn);
|
||
break;
|
||
|
||
case MEM:
|
||
return fold_rtx_mem (x, insn);
|
||
|
||
#ifdef NO_FUNCTION_CSE
|
||
case CALL:
|
||
if (CONSTANT_P (XEXP (XEXP (x, 0), 0)))
|
||
return x;
|
||
break;
|
||
#endif
|
||
|
||
case ASM_OPERANDS:
|
||
if (insn)
|
||
{
|
||
for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--)
|
||
validate_change (insn, &ASM_OPERANDS_INPUT (x, i),
|
||
fold_rtx (ASM_OPERANDS_INPUT (x, i), insn), 0);
|
||
}
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
const_arg0 = 0;
|
||
const_arg1 = 0;
|
||
const_arg2 = 0;
|
||
mode_arg0 = VOIDmode;
|
||
|
||
/* Try folding our operands.
|
||
Then see which ones have constant values known. */
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
if (fmt[i] == 'e')
|
||
{
|
||
rtx arg = XEXP (x, i);
|
||
rtx folded_arg = arg, const_arg = 0;
|
||
enum machine_mode mode_arg = GET_MODE (arg);
|
||
rtx cheap_arg, expensive_arg;
|
||
rtx replacements[2];
|
||
int j;
|
||
int old_cost = COST_IN (XEXP (x, i), code);
|
||
|
||
/* Most arguments are cheap, so handle them specially. */
|
||
switch (GET_CODE (arg))
|
||
{
|
||
case REG:
|
||
/* This is the same as calling equiv_constant; it is duplicated
|
||
here for speed. */
|
||
if (REGNO_QTY_VALID_P (REGNO (arg)))
|
||
{
|
||
int arg_q = REG_QTY (REGNO (arg));
|
||
struct qty_table_elem *arg_ent = &qty_table[arg_q];
|
||
|
||
if (arg_ent->const_rtx != NULL_RTX
|
||
&& !REG_P (arg_ent->const_rtx)
|
||
&& GET_CODE (arg_ent->const_rtx) != PLUS)
|
||
const_arg
|
||
= gen_lowpart (GET_MODE (arg),
|
||
arg_ent->const_rtx);
|
||
}
|
||
break;
|
||
|
||
case CONST:
|
||
case CONST_INT:
|
||
case SYMBOL_REF:
|
||
case LABEL_REF:
|
||
case CONST_DOUBLE:
|
||
case CONST_VECTOR:
|
||
const_arg = arg;
|
||
break;
|
||
|
||
#ifdef HAVE_cc0
|
||
case CC0:
|
||
folded_arg = prev_insn_cc0;
|
||
mode_arg = prev_insn_cc0_mode;
|
||
const_arg = equiv_constant (folded_arg);
|
||
break;
|
||
#endif
|
||
|
||
default:
|
||
folded_arg = fold_rtx (arg, insn);
|
||
const_arg = equiv_constant (folded_arg);
|
||
}
|
||
|
||
/* For the first three operands, see if the operand
|
||
is constant or equivalent to a constant. */
|
||
switch (i)
|
||
{
|
||
case 0:
|
||
folded_arg0 = folded_arg;
|
||
const_arg0 = const_arg;
|
||
mode_arg0 = mode_arg;
|
||
break;
|
||
case 1:
|
||
folded_arg1 = folded_arg;
|
||
const_arg1 = const_arg;
|
||
break;
|
||
case 2:
|
||
const_arg2 = const_arg;
|
||
break;
|
||
}
|
||
|
||
/* Pick the least expensive of the folded argument and an
|
||
equivalent constant argument. */
|
||
if (const_arg == 0 || const_arg == folded_arg
|
||
|| COST_IN (const_arg, code) > COST_IN (folded_arg, code))
|
||
cheap_arg = folded_arg, expensive_arg = const_arg;
|
||
else
|
||
cheap_arg = const_arg, expensive_arg = folded_arg;
|
||
|
||
/* Try to replace the operand with the cheapest of the two
|
||
possibilities. If it doesn't work and this is either of the first
|
||
two operands of a commutative operation, try swapping them.
|
||
If THAT fails, try the more expensive, provided it is cheaper
|
||
than what is already there. */
|
||
|
||
if (cheap_arg == XEXP (x, i))
|
||
continue;
|
||
|
||
if (insn == 0 && ! copied)
|
||
{
|
||
x = copy_rtx (x);
|
||
copied = 1;
|
||
}
|
||
|
||
/* Order the replacements from cheapest to most expensive. */
|
||
replacements[0] = cheap_arg;
|
||
replacements[1] = expensive_arg;
|
||
|
||
for (j = 0; j < 2 && replacements[j]; j++)
|
||
{
|
||
int new_cost = COST_IN (replacements[j], code);
|
||
|
||
/* Stop if what existed before was cheaper. Prefer constants
|
||
in the case of a tie. */
|
||
if (new_cost > old_cost
|
||
|| (new_cost == old_cost && CONSTANT_P (XEXP (x, i))))
|
||
break;
|
||
|
||
/* It's not safe to substitute the operand of a conversion
|
||
operator with a constant, as the conversion's identity
|
||
depends upon the mode of its operand. This optimization
|
||
is handled by the call to simplify_unary_operation. */
|
||
if (GET_RTX_CLASS (code) == RTX_UNARY
|
||
&& GET_MODE (replacements[j]) != mode_arg0
|
||
&& (code == ZERO_EXTEND
|
||
|| code == SIGN_EXTEND
|
||
|| code == TRUNCATE
|
||
|| code == FLOAT_TRUNCATE
|
||
|| code == FLOAT_EXTEND
|
||
|| code == FLOAT
|
||
|| code == FIX
|
||
|| code == UNSIGNED_FLOAT
|
||
|| code == UNSIGNED_FIX))
|
||
continue;
|
||
|
||
if (validate_change (insn, &XEXP (x, i), replacements[j], 0))
|
||
break;
|
||
|
||
if (GET_RTX_CLASS (code) == RTX_COMM_COMPARE
|
||
|| GET_RTX_CLASS (code) == RTX_COMM_ARITH)
|
||
{
|
||
validate_change (insn, &XEXP (x, i), XEXP (x, 1 - i), 1);
|
||
validate_change (insn, &XEXP (x, 1 - i), replacements[j], 1);
|
||
|
||
if (apply_change_group ())
|
||
{
|
||
/* Swap them back to be invalid so that this loop can
|
||
continue and flag them to be swapped back later. */
|
||
rtx tem;
|
||
|
||
tem = XEXP (x, 0); XEXP (x, 0) = XEXP (x, 1);
|
||
XEXP (x, 1) = tem;
|
||
must_swap = 1;
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
else
|
||
{
|
||
if (fmt[i] == 'E')
|
||
/* Don't try to fold inside of a vector of expressions.
|
||
Doing nothing is harmless. */
|
||
{;}
|
||
}
|
||
|
||
/* If a commutative operation, place a constant integer as the second
|
||
operand unless the first operand is also a constant integer. Otherwise,
|
||
place any constant second unless the first operand is also a constant. */
|
||
|
||
if (COMMUTATIVE_P (x))
|
||
{
|
||
if (must_swap
|
||
|| swap_commutative_operands_p (const_arg0 ? const_arg0
|
||
: XEXP (x, 0),
|
||
const_arg1 ? const_arg1
|
||
: XEXP (x, 1)))
|
||
{
|
||
rtx tem = XEXP (x, 0);
|
||
|
||
if (insn == 0 && ! copied)
|
||
{
|
||
x = copy_rtx (x);
|
||
copied = 1;
|
||
}
|
||
|
||
validate_change (insn, &XEXP (x, 0), XEXP (x, 1), 1);
|
||
validate_change (insn, &XEXP (x, 1), tem, 1);
|
||
if (apply_change_group ())
|
||
{
|
||
tem = const_arg0, const_arg0 = const_arg1, const_arg1 = tem;
|
||
tem = folded_arg0, folded_arg0 = folded_arg1, folded_arg1 = tem;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If X is an arithmetic operation, see if we can simplify it. */
|
||
|
||
switch (GET_RTX_CLASS (code))
|
||
{
|
||
case RTX_UNARY:
|
||
{
|
||
int is_const = 0;
|
||
|
||
/* We can't simplify extension ops unless we know the
|
||
original mode. */
|
||
if ((code == ZERO_EXTEND || code == SIGN_EXTEND)
|
||
&& mode_arg0 == VOIDmode)
|
||
break;
|
||
|
||
/* If we had a CONST, strip it off and put it back later if we
|
||
fold. */
|
||
if (const_arg0 != 0 && GET_CODE (const_arg0) == CONST)
|
||
is_const = 1, const_arg0 = XEXP (const_arg0, 0);
|
||
|
||
new = simplify_unary_operation (code, mode,
|
||
const_arg0 ? const_arg0 : folded_arg0,
|
||
mode_arg0);
|
||
/* NEG of PLUS could be converted into MINUS, but that causes
|
||
expressions of the form
|
||
(CONST (MINUS (CONST_INT) (SYMBOL_REF)))
|
||
which many ports mistakenly treat as LEGITIMATE_CONSTANT_P.
|
||
FIXME: those ports should be fixed. */
|
||
if (new != 0 && is_const
|
||
&& GET_CODE (new) == PLUS
|
||
&& (GET_CODE (XEXP (new, 0)) == SYMBOL_REF
|
||
|| GET_CODE (XEXP (new, 0)) == LABEL_REF)
|
||
&& GET_CODE (XEXP (new, 1)) == CONST_INT)
|
||
new = gen_rtx_CONST (mode, new);
|
||
}
|
||
break;
|
||
|
||
case RTX_COMPARE:
|
||
case RTX_COMM_COMPARE:
|
||
/* See what items are actually being compared and set FOLDED_ARG[01]
|
||
to those values and CODE to the actual comparison code. If any are
|
||
constant, set CONST_ARG0 and CONST_ARG1 appropriately. We needn't
|
||
do anything if both operands are already known to be constant. */
|
||
|
||
/* ??? Vector mode comparisons are not supported yet. */
|
||
if (VECTOR_MODE_P (mode))
|
||
break;
|
||
|
||
if (const_arg0 == 0 || const_arg1 == 0)
|
||
{
|
||
struct table_elt *p0, *p1;
|
||
rtx true_rtx = const_true_rtx, false_rtx = const0_rtx;
|
||
enum machine_mode mode_arg1;
|
||
|
||
#ifdef FLOAT_STORE_FLAG_VALUE
|
||
if (SCALAR_FLOAT_MODE_P (mode))
|
||
{
|
||
true_rtx = (CONST_DOUBLE_FROM_REAL_VALUE
|
||
(FLOAT_STORE_FLAG_VALUE (mode), mode));
|
||
false_rtx = CONST0_RTX (mode);
|
||
}
|
||
#endif
|
||
|
||
code = find_comparison_args (code, &folded_arg0, &folded_arg1,
|
||
&mode_arg0, &mode_arg1);
|
||
|
||
/* If the mode is VOIDmode or a MODE_CC mode, we don't know
|
||
what kinds of things are being compared, so we can't do
|
||
anything with this comparison. */
|
||
|
||
if (mode_arg0 == VOIDmode || GET_MODE_CLASS (mode_arg0) == MODE_CC)
|
||
break;
|
||
|
||
const_arg0 = equiv_constant (folded_arg0);
|
||
const_arg1 = equiv_constant (folded_arg1);
|
||
|
||
/* If we do not now have two constants being compared, see
|
||
if we can nevertheless deduce some things about the
|
||
comparison. */
|
||
if (const_arg0 == 0 || const_arg1 == 0)
|
||
{
|
||
if (const_arg1 != NULL)
|
||
{
|
||
rtx cheapest_simplification;
|
||
int cheapest_cost;
|
||
rtx simp_result;
|
||
struct table_elt *p;
|
||
|
||
/* See if we can find an equivalent of folded_arg0
|
||
that gets us a cheaper expression, possibly a
|
||
constant through simplifications. */
|
||
p = lookup (folded_arg0, SAFE_HASH (folded_arg0, mode_arg0),
|
||
mode_arg0);
|
||
|
||
if (p != NULL)
|
||
{
|
||
cheapest_simplification = x;
|
||
cheapest_cost = COST (x);
|
||
|
||
for (p = p->first_same_value; p != NULL; p = p->next_same_value)
|
||
{
|
||
int cost;
|
||
|
||
/* If the entry isn't valid, skip it. */
|
||
if (! exp_equiv_p (p->exp, p->exp, 1, false))
|
||
continue;
|
||
|
||
/* Try to simplify using this equivalence. */
|
||
simp_result
|
||
= simplify_relational_operation (code, mode,
|
||
mode_arg0,
|
||
p->exp,
|
||
const_arg1);
|
||
|
||
if (simp_result == NULL)
|
||
continue;
|
||
|
||
cost = COST (simp_result);
|
||
if (cost < cheapest_cost)
|
||
{
|
||
cheapest_cost = cost;
|
||
cheapest_simplification = simp_result;
|
||
}
|
||
}
|
||
|
||
/* If we have a cheaper expression now, use that
|
||
and try folding it further, from the top. */
|
||
if (cheapest_simplification != x)
|
||
return fold_rtx (cheapest_simplification, insn);
|
||
}
|
||
}
|
||
|
||
/* Some addresses are known to be nonzero. We don't know
|
||
their sign, but equality comparisons are known. */
|
||
if (const_arg1 == const0_rtx
|
||
&& nonzero_address_p (folded_arg0))
|
||
{
|
||
if (code == EQ)
|
||
return false_rtx;
|
||
else if (code == NE)
|
||
return true_rtx;
|
||
}
|
||
|
||
/* See if the two operands are the same. */
|
||
|
||
if (folded_arg0 == folded_arg1
|
||
|| (REG_P (folded_arg0)
|
||
&& REG_P (folded_arg1)
|
||
&& (REG_QTY (REGNO (folded_arg0))
|
||
== REG_QTY (REGNO (folded_arg1))))
|
||
|| ((p0 = lookup (folded_arg0,
|
||
SAFE_HASH (folded_arg0, mode_arg0),
|
||
mode_arg0))
|
||
&& (p1 = lookup (folded_arg1,
|
||
SAFE_HASH (folded_arg1, mode_arg0),
|
||
mode_arg0))
|
||
&& p0->first_same_value == p1->first_same_value))
|
||
{
|
||
/* Sadly two equal NaNs are not equivalent. */
|
||
if (!HONOR_NANS (mode_arg0))
|
||
return ((code == EQ || code == LE || code == GE
|
||
|| code == LEU || code == GEU || code == UNEQ
|
||
|| code == UNLE || code == UNGE
|
||
|| code == ORDERED)
|
||
? true_rtx : false_rtx);
|
||
/* Take care for the FP compares we can resolve. */
|
||
if (code == UNEQ || code == UNLE || code == UNGE)
|
||
return true_rtx;
|
||
if (code == LTGT || code == LT || code == GT)
|
||
return false_rtx;
|
||
}
|
||
|
||
/* If FOLDED_ARG0 is a register, see if the comparison we are
|
||
doing now is either the same as we did before or the reverse
|
||
(we only check the reverse if not floating-point). */
|
||
else if (REG_P (folded_arg0))
|
||
{
|
||
int qty = REG_QTY (REGNO (folded_arg0));
|
||
|
||
if (REGNO_QTY_VALID_P (REGNO (folded_arg0)))
|
||
{
|
||
struct qty_table_elem *ent = &qty_table[qty];
|
||
|
||
if ((comparison_dominates_p (ent->comparison_code, code)
|
||
|| (! FLOAT_MODE_P (mode_arg0)
|
||
&& comparison_dominates_p (ent->comparison_code,
|
||
reverse_condition (code))))
|
||
&& (rtx_equal_p (ent->comparison_const, folded_arg1)
|
||
|| (const_arg1
|
||
&& rtx_equal_p (ent->comparison_const,
|
||
const_arg1))
|
||
|| (REG_P (folded_arg1)
|
||
&& (REG_QTY (REGNO (folded_arg1)) == ent->comparison_qty))))
|
||
return (comparison_dominates_p (ent->comparison_code, code)
|
||
? true_rtx : false_rtx);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If we are comparing against zero, see if the first operand is
|
||
equivalent to an IOR with a constant. If so, we may be able to
|
||
determine the result of this comparison. */
|
||
|
||
if (const_arg1 == const0_rtx)
|
||
{
|
||
rtx y = lookup_as_function (folded_arg0, IOR);
|
||
rtx inner_const;
|
||
|
||
if (y != 0
|
||
&& (inner_const = equiv_constant (XEXP (y, 1))) != 0
|
||
&& GET_CODE (inner_const) == CONST_INT
|
||
&& INTVAL (inner_const) != 0)
|
||
{
|
||
int sign_bitnum = GET_MODE_BITSIZE (mode_arg0) - 1;
|
||
int has_sign = (HOST_BITS_PER_WIDE_INT >= sign_bitnum
|
||
&& (INTVAL (inner_const)
|
||
& ((HOST_WIDE_INT) 1 << sign_bitnum)));
|
||
rtx true_rtx = const_true_rtx, false_rtx = const0_rtx;
|
||
|
||
#ifdef FLOAT_STORE_FLAG_VALUE
|
||
if (SCALAR_FLOAT_MODE_P (mode))
|
||
{
|
||
true_rtx = (CONST_DOUBLE_FROM_REAL_VALUE
|
||
(FLOAT_STORE_FLAG_VALUE (mode), mode));
|
||
false_rtx = CONST0_RTX (mode);
|
||
}
|
||
#endif
|
||
|
||
switch (code)
|
||
{
|
||
case EQ:
|
||
return false_rtx;
|
||
case NE:
|
||
return true_rtx;
|
||
case LT: case LE:
|
||
if (has_sign)
|
||
return true_rtx;
|
||
break;
|
||
case GT: case GE:
|
||
if (has_sign)
|
||
return false_rtx;
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
{
|
||
rtx op0 = const_arg0 ? const_arg0 : folded_arg0;
|
||
rtx op1 = const_arg1 ? const_arg1 : folded_arg1;
|
||
new = simplify_relational_operation (code, mode, mode_arg0, op0, op1);
|
||
}
|
||
break;
|
||
|
||
case RTX_BIN_ARITH:
|
||
case RTX_COMM_ARITH:
|
||
switch (code)
|
||
{
|
||
case PLUS:
|
||
/* If the second operand is a LABEL_REF, see if the first is a MINUS
|
||
with that LABEL_REF as its second operand. If so, the result is
|
||
the first operand of that MINUS. This handles switches with an
|
||
ADDR_DIFF_VEC table. */
|
||
if (const_arg1 && GET_CODE (const_arg1) == LABEL_REF)
|
||
{
|
||
rtx y
|
||
= GET_CODE (folded_arg0) == MINUS ? folded_arg0
|
||
: lookup_as_function (folded_arg0, MINUS);
|
||
|
||
if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF
|
||
&& XEXP (XEXP (y, 1), 0) == XEXP (const_arg1, 0))
|
||
return XEXP (y, 0);
|
||
|
||
/* Now try for a CONST of a MINUS like the above. */
|
||
if ((y = (GET_CODE (folded_arg0) == CONST ? folded_arg0
|
||
: lookup_as_function (folded_arg0, CONST))) != 0
|
||
&& GET_CODE (XEXP (y, 0)) == MINUS
|
||
&& GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF
|
||
&& XEXP (XEXP (XEXP (y, 0), 1), 0) == XEXP (const_arg1, 0))
|
||
return XEXP (XEXP (y, 0), 0);
|
||
}
|
||
|
||
/* Likewise if the operands are in the other order. */
|
||
if (const_arg0 && GET_CODE (const_arg0) == LABEL_REF)
|
||
{
|
||
rtx y
|
||
= GET_CODE (folded_arg1) == MINUS ? folded_arg1
|
||
: lookup_as_function (folded_arg1, MINUS);
|
||
|
||
if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF
|
||
&& XEXP (XEXP (y, 1), 0) == XEXP (const_arg0, 0))
|
||
return XEXP (y, 0);
|
||
|
||
/* Now try for a CONST of a MINUS like the above. */
|
||
if ((y = (GET_CODE (folded_arg1) == CONST ? folded_arg1
|
||
: lookup_as_function (folded_arg1, CONST))) != 0
|
||
&& GET_CODE (XEXP (y, 0)) == MINUS
|
||
&& GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF
|
||
&& XEXP (XEXP (XEXP (y, 0), 1), 0) == XEXP (const_arg0, 0))
|
||
return XEXP (XEXP (y, 0), 0);
|
||
}
|
||
|
||
/* If second operand is a register equivalent to a negative
|
||
CONST_INT, see if we can find a register equivalent to the
|
||
positive constant. Make a MINUS if so. Don't do this for
|
||
a non-negative constant since we might then alternate between
|
||
choosing positive and negative constants. Having the positive
|
||
constant previously-used is the more common case. Be sure
|
||
the resulting constant is non-negative; if const_arg1 were
|
||
the smallest negative number this would overflow: depending
|
||
on the mode, this would either just be the same value (and
|
||
hence not save anything) or be incorrect. */
|
||
if (const_arg1 != 0 && GET_CODE (const_arg1) == CONST_INT
|
||
&& INTVAL (const_arg1) < 0
|
||
/* This used to test
|
||
|
||
-INTVAL (const_arg1) >= 0
|
||
|
||
But The Sun V5.0 compilers mis-compiled that test. So
|
||
instead we test for the problematic value in a more direct
|
||
manner and hope the Sun compilers get it correct. */
|
||
&& INTVAL (const_arg1) !=
|
||
((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT - 1))
|
||
&& REG_P (folded_arg1))
|
||
{
|
||
rtx new_const = GEN_INT (-INTVAL (const_arg1));
|
||
struct table_elt *p
|
||
= lookup (new_const, SAFE_HASH (new_const, mode), mode);
|
||
|
||
if (p)
|
||
for (p = p->first_same_value; p; p = p->next_same_value)
|
||
if (REG_P (p->exp))
|
||
return simplify_gen_binary (MINUS, mode, folded_arg0,
|
||
canon_reg (p->exp, NULL_RTX));
|
||
}
|
||
goto from_plus;
|
||
|
||
case MINUS:
|
||
/* If we have (MINUS Y C), see if Y is known to be (PLUS Z C2).
|
||
If so, produce (PLUS Z C2-C). */
|
||
if (const_arg1 != 0 && GET_CODE (const_arg1) == CONST_INT)
|
||
{
|
||
rtx y = lookup_as_function (XEXP (x, 0), PLUS);
|
||
if (y && GET_CODE (XEXP (y, 1)) == CONST_INT)
|
||
return fold_rtx (plus_constant (copy_rtx (y),
|
||
-INTVAL (const_arg1)),
|
||
NULL_RTX);
|
||
}
|
||
|
||
/* Fall through. */
|
||
|
||
from_plus:
|
||
case SMIN: case SMAX: case UMIN: case UMAX:
|
||
case IOR: case AND: case XOR:
|
||
case MULT:
|
||
case ASHIFT: case LSHIFTRT: case ASHIFTRT:
|
||
/* If we have (<op> <reg> <const_int>) for an associative OP and REG
|
||
is known to be of similar form, we may be able to replace the
|
||
operation with a combined operation. This may eliminate the
|
||
intermediate operation if every use is simplified in this way.
|
||
Note that the similar optimization done by combine.c only works
|
||
if the intermediate operation's result has only one reference. */
|
||
|
||
if (REG_P (folded_arg0)
|
||
&& const_arg1 && GET_CODE (const_arg1) == CONST_INT)
|
||
{
|
||
int is_shift
|
||
= (code == ASHIFT || code == ASHIFTRT || code == LSHIFTRT);
|
||
rtx y, inner_const, new_const;
|
||
enum rtx_code associate_code;
|
||
|
||
if (is_shift
|
||
&& (INTVAL (const_arg1) >= GET_MODE_BITSIZE (mode)
|
||
|| INTVAL (const_arg1) < 0))
|
||
{
|
||
if (SHIFT_COUNT_TRUNCATED)
|
||
const_arg1 = GEN_INT (INTVAL (const_arg1)
|
||
& (GET_MODE_BITSIZE (mode) - 1));
|
||
else
|
||
break;
|
||
}
|
||
|
||
y = lookup_as_function (folded_arg0, code);
|
||
if (y == 0)
|
||
break;
|
||
|
||
/* If we have compiled a statement like
|
||
"if (x == (x & mask1))", and now are looking at
|
||
"x & mask2", we will have a case where the first operand
|
||
of Y is the same as our first operand. Unless we detect
|
||
this case, an infinite loop will result. */
|
||
if (XEXP (y, 0) == folded_arg0)
|
||
break;
|
||
|
||
inner_const = equiv_constant (fold_rtx (XEXP (y, 1), 0));
|
||
if (!inner_const || GET_CODE (inner_const) != CONST_INT)
|
||
break;
|
||
|
||
/* Don't associate these operations if they are a PLUS with the
|
||
same constant and it is a power of two. These might be doable
|
||
with a pre- or post-increment. Similarly for two subtracts of
|
||
identical powers of two with post decrement. */
|
||
|
||
if (code == PLUS && const_arg1 == inner_const
|
||
&& ((HAVE_PRE_INCREMENT
|
||
&& exact_log2 (INTVAL (const_arg1)) >= 0)
|
||
|| (HAVE_POST_INCREMENT
|
||
&& exact_log2 (INTVAL (const_arg1)) >= 0)
|
||
|| (HAVE_PRE_DECREMENT
|
||
&& exact_log2 (- INTVAL (const_arg1)) >= 0)
|
||
|| (HAVE_POST_DECREMENT
|
||
&& exact_log2 (- INTVAL (const_arg1)) >= 0)))
|
||
break;
|
||
|
||
if (is_shift
|
||
&& (INTVAL (inner_const) >= GET_MODE_BITSIZE (mode)
|
||
|| INTVAL (inner_const) < 0))
|
||
{
|
||
if (SHIFT_COUNT_TRUNCATED)
|
||
inner_const = GEN_INT (INTVAL (inner_const)
|
||
& (GET_MODE_BITSIZE (mode) - 1));
|
||
else
|
||
break;
|
||
}
|
||
|
||
/* Compute the code used to compose the constants. For example,
|
||
A-C1-C2 is A-(C1 + C2), so if CODE == MINUS, we want PLUS. */
|
||
|
||
associate_code = (is_shift || code == MINUS ? PLUS : code);
|
||
|
||
new_const = simplify_binary_operation (associate_code, mode,
|
||
const_arg1, inner_const);
|
||
|
||
if (new_const == 0)
|
||
break;
|
||
|
||
/* If we are associating shift operations, don't let this
|
||
produce a shift of the size of the object or larger.
|
||
This could occur when we follow a sign-extend by a right
|
||
shift on a machine that does a sign-extend as a pair
|
||
of shifts. */
|
||
|
||
if (is_shift
|
||
&& GET_CODE (new_const) == CONST_INT
|
||
&& INTVAL (new_const) >= GET_MODE_BITSIZE (mode))
|
||
{
|
||
/* As an exception, we can turn an ASHIFTRT of this
|
||
form into a shift of the number of bits - 1. */
|
||
if (code == ASHIFTRT)
|
||
new_const = GEN_INT (GET_MODE_BITSIZE (mode) - 1);
|
||
else if (!side_effects_p (XEXP (y, 0)))
|
||
return CONST0_RTX (mode);
|
||
else
|
||
break;
|
||
}
|
||
|
||
y = copy_rtx (XEXP (y, 0));
|
||
|
||
/* If Y contains our first operand (the most common way this
|
||
can happen is if Y is a MEM), we would do into an infinite
|
||
loop if we tried to fold it. So don't in that case. */
|
||
|
||
if (! reg_mentioned_p (folded_arg0, y))
|
||
y = fold_rtx (y, insn);
|
||
|
||
return simplify_gen_binary (code, mode, y, new_const);
|
||
}
|
||
break;
|
||
|
||
case DIV: case UDIV:
|
||
/* ??? The associative optimization performed immediately above is
|
||
also possible for DIV and UDIV using associate_code of MULT.
|
||
However, we would need extra code to verify that the
|
||
multiplication does not overflow, that is, there is no overflow
|
||
in the calculation of new_const. */
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
new = simplify_binary_operation (code, mode,
|
||
const_arg0 ? const_arg0 : folded_arg0,
|
||
const_arg1 ? const_arg1 : folded_arg1);
|
||
break;
|
||
|
||
case RTX_OBJ:
|
||
/* (lo_sum (high X) X) is simply X. */
|
||
if (code == LO_SUM && const_arg0 != 0
|
||
&& GET_CODE (const_arg0) == HIGH
|
||
&& rtx_equal_p (XEXP (const_arg0, 0), const_arg1))
|
||
return const_arg1;
|
||
break;
|
||
|
||
case RTX_TERNARY:
|
||
case RTX_BITFIELD_OPS:
|
||
new = simplify_ternary_operation (code, mode, mode_arg0,
|
||
const_arg0 ? const_arg0 : folded_arg0,
|
||
const_arg1 ? const_arg1 : folded_arg1,
|
||
const_arg2 ? const_arg2 : XEXP (x, 2));
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
return new ? new : x;
|
||
}
|
||
|
||
/* Return a constant value currently equivalent to X.
|
||
Return 0 if we don't know one. */
|
||
|
||
static rtx
|
||
equiv_constant (rtx x)
|
||
{
|
||
if (REG_P (x)
|
||
&& REGNO_QTY_VALID_P (REGNO (x)))
|
||
{
|
||
int x_q = REG_QTY (REGNO (x));
|
||
struct qty_table_elem *x_ent = &qty_table[x_q];
|
||
|
||
if (x_ent->const_rtx)
|
||
x = gen_lowpart (GET_MODE (x), x_ent->const_rtx);
|
||
}
|
||
|
||
if (x == 0 || CONSTANT_P (x))
|
||
return x;
|
||
|
||
/* If X is a MEM, try to fold it outside the context of any insn to see if
|
||
it might be equivalent to a constant. That handles the case where it
|
||
is a constant-pool reference. Then try to look it up in the hash table
|
||
in case it is something whose value we have seen before. */
|
||
|
||
if (MEM_P (x))
|
||
{
|
||
struct table_elt *elt;
|
||
|
||
x = fold_rtx (x, NULL_RTX);
|
||
if (CONSTANT_P (x))
|
||
return x;
|
||
|
||
elt = lookup (x, SAFE_HASH (x, GET_MODE (x)), GET_MODE (x));
|
||
if (elt == 0)
|
||
return 0;
|
||
|
||
for (elt = elt->first_same_value; elt; elt = elt->next_same_value)
|
||
if (elt->is_const && CONSTANT_P (elt->exp))
|
||
return elt->exp;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Given INSN, a jump insn, PATH_TAKEN indicates if we are following the "taken"
|
||
branch. It will be zero if not.
|
||
|
||
In certain cases, this can cause us to add an equivalence. For example,
|
||
if we are following the taken case of
|
||
if (i == 2)
|
||
we can add the fact that `i' and '2' are now equivalent.
|
||
|
||
In any case, we can record that this comparison was passed. If the same
|
||
comparison is seen later, we will know its value. */
|
||
|
||
static void
|
||
record_jump_equiv (rtx insn, int taken)
|
||
{
|
||
int cond_known_true;
|
||
rtx op0, op1;
|
||
rtx set;
|
||
enum machine_mode mode, mode0, mode1;
|
||
int reversed_nonequality = 0;
|
||
enum rtx_code code;
|
||
|
||
/* Ensure this is the right kind of insn. */
|
||
if (! any_condjump_p (insn))
|
||
return;
|
||
set = pc_set (insn);
|
||
|
||
/* See if this jump condition is known true or false. */
|
||
if (taken)
|
||
cond_known_true = (XEXP (SET_SRC (set), 2) == pc_rtx);
|
||
else
|
||
cond_known_true = (XEXP (SET_SRC (set), 1) == pc_rtx);
|
||
|
||
/* Get the type of comparison being done and the operands being compared.
|
||
If we had to reverse a non-equality condition, record that fact so we
|
||
know that it isn't valid for floating-point. */
|
||
code = GET_CODE (XEXP (SET_SRC (set), 0));
|
||
op0 = fold_rtx (XEXP (XEXP (SET_SRC (set), 0), 0), insn);
|
||
op1 = fold_rtx (XEXP (XEXP (SET_SRC (set), 0), 1), insn);
|
||
|
||
code = find_comparison_args (code, &op0, &op1, &mode0, &mode1);
|
||
|
||
/* If the mode is a MODE_CC mode, we don't know what kinds of things
|
||
are being compared, so we can't do anything with this
|
||
comparison. */
|
||
|
||
if (GET_MODE_CLASS (mode0) == MODE_CC)
|
||
return;
|
||
|
||
if (! cond_known_true)
|
||
{
|
||
code = reversed_comparison_code_parts (code, op0, op1, insn);
|
||
|
||
/* Don't remember if we can't find the inverse. */
|
||
if (code == UNKNOWN)
|
||
return;
|
||
}
|
||
|
||
/* The mode is the mode of the non-constant. */
|
||
mode = mode0;
|
||
if (mode1 != VOIDmode)
|
||
mode = mode1;
|
||
|
||
record_jump_cond (code, mode, op0, op1, reversed_nonequality);
|
||
}
|
||
|
||
/* Yet another form of subreg creation. In this case, we want something in
|
||
MODE, and we should assume OP has MODE iff it is naturally modeless. */
|
||
|
||
static rtx
|
||
record_jump_cond_subreg (enum machine_mode mode, rtx op)
|
||
{
|
||
enum machine_mode op_mode = GET_MODE (op);
|
||
if (op_mode == mode || op_mode == VOIDmode)
|
||
return op;
|
||
return lowpart_subreg (mode, op, op_mode);
|
||
}
|
||
|
||
/* We know that comparison CODE applied to OP0 and OP1 in MODE is true.
|
||
REVERSED_NONEQUALITY is nonzero if CODE had to be swapped.
|
||
Make any useful entries we can with that information. Called from
|
||
above function and called recursively. */
|
||
|
||
static void
|
||
record_jump_cond (enum rtx_code code, enum machine_mode mode, rtx op0,
|
||
rtx op1, int reversed_nonequality)
|
||
{
|
||
unsigned op0_hash, op1_hash;
|
||
int op0_in_memory, op1_in_memory;
|
||
struct table_elt *op0_elt, *op1_elt;
|
||
|
||
/* If OP0 and OP1 are known equal, and either is a paradoxical SUBREG,
|
||
we know that they are also equal in the smaller mode (this is also
|
||
true for all smaller modes whether or not there is a SUBREG, but
|
||
is not worth testing for with no SUBREG). */
|
||
|
||
/* Note that GET_MODE (op0) may not equal MODE. */
|
||
if (code == EQ && GET_CODE (op0) == SUBREG
|
||
&& (GET_MODE_SIZE (GET_MODE (op0))
|
||
> GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))
|
||
{
|
||
enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
|
||
rtx tem = record_jump_cond_subreg (inner_mode, op1);
|
||
if (tem)
|
||
record_jump_cond (code, mode, SUBREG_REG (op0), tem,
|
||
reversed_nonequality);
|
||
}
|
||
|
||
if (code == EQ && GET_CODE (op1) == SUBREG
|
||
&& (GET_MODE_SIZE (GET_MODE (op1))
|
||
> GET_MODE_SIZE (GET_MODE (SUBREG_REG (op1)))))
|
||
{
|
||
enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1));
|
||
rtx tem = record_jump_cond_subreg (inner_mode, op0);
|
||
if (tem)
|
||
record_jump_cond (code, mode, SUBREG_REG (op1), tem,
|
||
reversed_nonequality);
|
||
}
|
||
|
||
/* Similarly, if this is an NE comparison, and either is a SUBREG
|
||
making a smaller mode, we know the whole thing is also NE. */
|
||
|
||
/* Note that GET_MODE (op0) may not equal MODE;
|
||
if we test MODE instead, we can get an infinite recursion
|
||
alternating between two modes each wider than MODE. */
|
||
|
||
if (code == NE && GET_CODE (op0) == SUBREG
|
||
&& subreg_lowpart_p (op0)
|
||
&& (GET_MODE_SIZE (GET_MODE (op0))
|
||
< GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))
|
||
{
|
||
enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
|
||
rtx tem = record_jump_cond_subreg (inner_mode, op1);
|
||
if (tem)
|
||
record_jump_cond (code, mode, SUBREG_REG (op0), tem,
|
||
reversed_nonequality);
|
||
}
|
||
|
||
if (code == NE && GET_CODE (op1) == SUBREG
|
||
&& subreg_lowpart_p (op1)
|
||
&& (GET_MODE_SIZE (GET_MODE (op1))
|
||
< GET_MODE_SIZE (GET_MODE (SUBREG_REG (op1)))))
|
||
{
|
||
enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1));
|
||
rtx tem = record_jump_cond_subreg (inner_mode, op0);
|
||
if (tem)
|
||
record_jump_cond (code, mode, SUBREG_REG (op1), tem,
|
||
reversed_nonequality);
|
||
}
|
||
|
||
/* Hash both operands. */
|
||
|
||
do_not_record = 0;
|
||
hash_arg_in_memory = 0;
|
||
op0_hash = HASH (op0, mode);
|
||
op0_in_memory = hash_arg_in_memory;
|
||
|
||
if (do_not_record)
|
||
return;
|
||
|
||
do_not_record = 0;
|
||
hash_arg_in_memory = 0;
|
||
op1_hash = HASH (op1, mode);
|
||
op1_in_memory = hash_arg_in_memory;
|
||
|
||
if (do_not_record)
|
||
return;
|
||
|
||
/* Look up both operands. */
|
||
op0_elt = lookup (op0, op0_hash, mode);
|
||
op1_elt = lookup (op1, op1_hash, mode);
|
||
|
||
/* If both operands are already equivalent or if they are not in the
|
||
table but are identical, do nothing. */
|
||
if ((op0_elt != 0 && op1_elt != 0
|
||
&& op0_elt->first_same_value == op1_elt->first_same_value)
|
||
|| op0 == op1 || rtx_equal_p (op0, op1))
|
||
return;
|
||
|
||
/* If we aren't setting two things equal all we can do is save this
|
||
comparison. Similarly if this is floating-point. In the latter
|
||
case, OP1 might be zero and both -0.0 and 0.0 are equal to it.
|
||
If we record the equality, we might inadvertently delete code
|
||
whose intent was to change -0 to +0. */
|
||
|
||
if (code != EQ || FLOAT_MODE_P (GET_MODE (op0)))
|
||
{
|
||
struct qty_table_elem *ent;
|
||
int qty;
|
||
|
||
/* If we reversed a floating-point comparison, if OP0 is not a
|
||
register, or if OP1 is neither a register or constant, we can't
|
||
do anything. */
|
||
|
||
if (!REG_P (op1))
|
||
op1 = equiv_constant (op1);
|
||
|
||
if ((reversed_nonequality && FLOAT_MODE_P (mode))
|
||
|| !REG_P (op0) || op1 == 0)
|
||
return;
|
||
|
||
/* Put OP0 in the hash table if it isn't already. This gives it a
|
||
new quantity number. */
|
||
if (op0_elt == 0)
|
||
{
|
||
if (insert_regs (op0, NULL, 0))
|
||
{
|
||
rehash_using_reg (op0);
|
||
op0_hash = HASH (op0, mode);
|
||
|
||
/* If OP0 is contained in OP1, this changes its hash code
|
||
as well. Faster to rehash than to check, except
|
||
for the simple case of a constant. */
|
||
if (! CONSTANT_P (op1))
|
||
op1_hash = HASH (op1,mode);
|
||
}
|
||
|
||
op0_elt = insert (op0, NULL, op0_hash, mode);
|
||
op0_elt->in_memory = op0_in_memory;
|
||
}
|
||
|
||
qty = REG_QTY (REGNO (op0));
|
||
ent = &qty_table[qty];
|
||
|
||
ent->comparison_code = code;
|
||
if (REG_P (op1))
|
||
{
|
||
/* Look it up again--in case op0 and op1 are the same. */
|
||
op1_elt = lookup (op1, op1_hash, mode);
|
||
|
||
/* Put OP1 in the hash table so it gets a new quantity number. */
|
||
if (op1_elt == 0)
|
||
{
|
||
if (insert_regs (op1, NULL, 0))
|
||
{
|
||
rehash_using_reg (op1);
|
||
op1_hash = HASH (op1, mode);
|
||
}
|
||
|
||
op1_elt = insert (op1, NULL, op1_hash, mode);
|
||
op1_elt->in_memory = op1_in_memory;
|
||
}
|
||
|
||
ent->comparison_const = NULL_RTX;
|
||
ent->comparison_qty = REG_QTY (REGNO (op1));
|
||
}
|
||
else
|
||
{
|
||
ent->comparison_const = op1;
|
||
ent->comparison_qty = -1;
|
||
}
|
||
|
||
return;
|
||
}
|
||
|
||
/* If either side is still missing an equivalence, make it now,
|
||
then merge the equivalences. */
|
||
|
||
if (op0_elt == 0)
|
||
{
|
||
if (insert_regs (op0, NULL, 0))
|
||
{
|
||
rehash_using_reg (op0);
|
||
op0_hash = HASH (op0, mode);
|
||
}
|
||
|
||
op0_elt = insert (op0, NULL, op0_hash, mode);
|
||
op0_elt->in_memory = op0_in_memory;
|
||
}
|
||
|
||
if (op1_elt == 0)
|
||
{
|
||
if (insert_regs (op1, NULL, 0))
|
||
{
|
||
rehash_using_reg (op1);
|
||
op1_hash = HASH (op1, mode);
|
||
}
|
||
|
||
op1_elt = insert (op1, NULL, op1_hash, mode);
|
||
op1_elt->in_memory = op1_in_memory;
|
||
}
|
||
|
||
merge_equiv_classes (op0_elt, op1_elt);
|
||
}
|
||
|
||
/* CSE processing for one instruction.
|
||
First simplify sources and addresses of all assignments
|
||
in the instruction, using previously-computed equivalents values.
|
||
Then install the new sources and destinations in the table
|
||
of available values.
|
||
|
||
If LIBCALL_INSN is nonzero, don't record any equivalence made in
|
||
the insn. It means that INSN is inside libcall block. In this
|
||
case LIBCALL_INSN is the corresponding insn with REG_LIBCALL. */
|
||
|
||
/* Data on one SET contained in the instruction. */
|
||
|
||
struct set
|
||
{
|
||
/* The SET rtx itself. */
|
||
rtx rtl;
|
||
/* The SET_SRC of the rtx (the original value, if it is changing). */
|
||
rtx src;
|
||
/* The hash-table element for the SET_SRC of the SET. */
|
||
struct table_elt *src_elt;
|
||
/* Hash value for the SET_SRC. */
|
||
unsigned src_hash;
|
||
/* Hash value for the SET_DEST. */
|
||
unsigned dest_hash;
|
||
/* The SET_DEST, with SUBREG, etc., stripped. */
|
||
rtx inner_dest;
|
||
/* Nonzero if the SET_SRC is in memory. */
|
||
char src_in_memory;
|
||
/* Nonzero if the SET_SRC contains something
|
||
whose value cannot be predicted and understood. */
|
||
char src_volatile;
|
||
/* Original machine mode, in case it becomes a CONST_INT.
|
||
The size of this field should match the size of the mode
|
||
field of struct rtx_def (see rtl.h). */
|
||
ENUM_BITFIELD(machine_mode) mode : 8;
|
||
/* A constant equivalent for SET_SRC, if any. */
|
||
rtx src_const;
|
||
/* Original SET_SRC value used for libcall notes. */
|
||
rtx orig_src;
|
||
/* Hash value of constant equivalent for SET_SRC. */
|
||
unsigned src_const_hash;
|
||
/* Table entry for constant equivalent for SET_SRC, if any. */
|
||
struct table_elt *src_const_elt;
|
||
/* Table entry for the destination address. */
|
||
struct table_elt *dest_addr_elt;
|
||
};
|
||
|
||
static void
|
||
cse_insn (rtx insn, rtx libcall_insn)
|
||
{
|
||
rtx x = PATTERN (insn);
|
||
int i;
|
||
rtx tem;
|
||
int n_sets = 0;
|
||
|
||
#ifdef HAVE_cc0
|
||
/* Records what this insn does to set CC0. */
|
||
rtx this_insn_cc0 = 0;
|
||
enum machine_mode this_insn_cc0_mode = VOIDmode;
|
||
#endif
|
||
|
||
rtx src_eqv = 0;
|
||
struct table_elt *src_eqv_elt = 0;
|
||
int src_eqv_volatile = 0;
|
||
int src_eqv_in_memory = 0;
|
||
unsigned src_eqv_hash = 0;
|
||
|
||
struct set *sets = (struct set *) 0;
|
||
|
||
this_insn = insn;
|
||
|
||
/* Find all the SETs and CLOBBERs in this instruction.
|
||
Record all the SETs in the array `set' and count them.
|
||
Also determine whether there is a CLOBBER that invalidates
|
||
all memory references, or all references at varying addresses. */
|
||
|
||
if (CALL_P (insn))
|
||
{
|
||
for (tem = CALL_INSN_FUNCTION_USAGE (insn); tem; tem = XEXP (tem, 1))
|
||
{
|
||
if (GET_CODE (XEXP (tem, 0)) == CLOBBER)
|
||
invalidate (SET_DEST (XEXP (tem, 0)), VOIDmode);
|
||
XEXP (tem, 0) = canon_reg (XEXP (tem, 0), insn);
|
||
}
|
||
}
|
||
|
||
if (GET_CODE (x) == SET)
|
||
{
|
||
sets = alloca (sizeof (struct set));
|
||
sets[0].rtl = x;
|
||
|
||
/* Ignore SETs that are unconditional jumps.
|
||
They never need cse processing, so this does not hurt.
|
||
The reason is not efficiency but rather
|
||
so that we can test at the end for instructions
|
||
that have been simplified to unconditional jumps
|
||
and not be misled by unchanged instructions
|
||
that were unconditional jumps to begin with. */
|
||
if (SET_DEST (x) == pc_rtx
|
||
&& GET_CODE (SET_SRC (x)) == LABEL_REF)
|
||
;
|
||
|
||
/* Don't count call-insns, (set (reg 0) (call ...)), as a set.
|
||
The hard function value register is used only once, to copy to
|
||
someplace else, so it isn't worth cse'ing (and on 80386 is unsafe)!
|
||
Ensure we invalidate the destination register. On the 80386 no
|
||
other code would invalidate it since it is a fixed_reg.
|
||
We need not check the return of apply_change_group; see canon_reg. */
|
||
|
||
else if (GET_CODE (SET_SRC (x)) == CALL)
|
||
{
|
||
canon_reg (SET_SRC (x), insn);
|
||
apply_change_group ();
|
||
fold_rtx (SET_SRC (x), insn);
|
||
invalidate (SET_DEST (x), VOIDmode);
|
||
}
|
||
else
|
||
n_sets = 1;
|
||
}
|
||
else if (GET_CODE (x) == PARALLEL)
|
||
{
|
||
int lim = XVECLEN (x, 0);
|
||
|
||
sets = alloca (lim * sizeof (struct set));
|
||
|
||
/* Find all regs explicitly clobbered in this insn,
|
||
and ensure they are not replaced with any other regs
|
||
elsewhere in this insn.
|
||
When a reg that is clobbered is also used for input,
|
||
we should presume that that is for a reason,
|
||
and we should not substitute some other register
|
||
which is not supposed to be clobbered.
|
||
Therefore, this loop cannot be merged into the one below
|
||
because a CALL may precede a CLOBBER and refer to the
|
||
value clobbered. We must not let a canonicalization do
|
||
anything in that case. */
|
||
for (i = 0; i < lim; i++)
|
||
{
|
||
rtx y = XVECEXP (x, 0, i);
|
||
if (GET_CODE (y) == CLOBBER)
|
||
{
|
||
rtx clobbered = XEXP (y, 0);
|
||
|
||
if (REG_P (clobbered)
|
||
|| GET_CODE (clobbered) == SUBREG)
|
||
invalidate (clobbered, VOIDmode);
|
||
else if (GET_CODE (clobbered) == STRICT_LOW_PART
|
||
|| GET_CODE (clobbered) == ZERO_EXTRACT)
|
||
invalidate (XEXP (clobbered, 0), GET_MODE (clobbered));
|
||
}
|
||
}
|
||
|
||
for (i = 0; i < lim; i++)
|
||
{
|
||
rtx y = XVECEXP (x, 0, i);
|
||
if (GET_CODE (y) == SET)
|
||
{
|
||
/* As above, we ignore unconditional jumps and call-insns and
|
||
ignore the result of apply_change_group. */
|
||
if (GET_CODE (SET_SRC (y)) == CALL)
|
||
{
|
||
canon_reg (SET_SRC (y), insn);
|
||
apply_change_group ();
|
||
fold_rtx (SET_SRC (y), insn);
|
||
invalidate (SET_DEST (y), VOIDmode);
|
||
}
|
||
else if (SET_DEST (y) == pc_rtx
|
||
&& GET_CODE (SET_SRC (y)) == LABEL_REF)
|
||
;
|
||
else
|
||
sets[n_sets++].rtl = y;
|
||
}
|
||
else if (GET_CODE (y) == CLOBBER)
|
||
{
|
||
/* If we clobber memory, canon the address.
|
||
This does nothing when a register is clobbered
|
||
because we have already invalidated the reg. */
|
||
if (MEM_P (XEXP (y, 0)))
|
||
canon_reg (XEXP (y, 0), NULL_RTX);
|
||
}
|
||
else if (GET_CODE (y) == USE
|
||
&& ! (REG_P (XEXP (y, 0))
|
||
&& REGNO (XEXP (y, 0)) < FIRST_PSEUDO_REGISTER))
|
||
canon_reg (y, NULL_RTX);
|
||
else if (GET_CODE (y) == CALL)
|
||
{
|
||
/* The result of apply_change_group can be ignored; see
|
||
canon_reg. */
|
||
canon_reg (y, insn);
|
||
apply_change_group ();
|
||
fold_rtx (y, insn);
|
||
}
|
||
}
|
||
}
|
||
else if (GET_CODE (x) == CLOBBER)
|
||
{
|
||
if (MEM_P (XEXP (x, 0)))
|
||
canon_reg (XEXP (x, 0), NULL_RTX);
|
||
}
|
||
|
||
/* Canonicalize a USE of a pseudo register or memory location. */
|
||
else if (GET_CODE (x) == USE
|
||
&& ! (REG_P (XEXP (x, 0))
|
||
&& REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER))
|
||
canon_reg (XEXP (x, 0), NULL_RTX);
|
||
else if (GET_CODE (x) == CALL)
|
||
{
|
||
/* The result of apply_change_group can be ignored; see canon_reg. */
|
||
canon_reg (x, insn);
|
||
apply_change_group ();
|
||
fold_rtx (x, insn);
|
||
}
|
||
|
||
/* Store the equivalent value in SRC_EQV, if different, or if the DEST
|
||
is a STRICT_LOW_PART. The latter condition is necessary because SRC_EQV
|
||
is handled specially for this case, and if it isn't set, then there will
|
||
be no equivalence for the destination. */
|
||
if (n_sets == 1 && REG_NOTES (insn) != 0
|
||
&& (tem = find_reg_note (insn, REG_EQUAL, NULL_RTX)) != 0
|
||
&& (! rtx_equal_p (XEXP (tem, 0), SET_SRC (sets[0].rtl))
|
||
|| GET_CODE (SET_DEST (sets[0].rtl)) == STRICT_LOW_PART))
|
||
{
|
||
src_eqv = fold_rtx (canon_reg (XEXP (tem, 0), NULL_RTX), insn);
|
||
XEXP (tem, 0) = src_eqv;
|
||
}
|
||
|
||
/* Canonicalize sources and addresses of destinations.
|
||
We do this in a separate pass to avoid problems when a MATCH_DUP is
|
||
present in the insn pattern. In that case, we want to ensure that
|
||
we don't break the duplicate nature of the pattern. So we will replace
|
||
both operands at the same time. Otherwise, we would fail to find an
|
||
equivalent substitution in the loop calling validate_change below.
|
||
|
||
We used to suppress canonicalization of DEST if it appears in SRC,
|
||
but we don't do this any more. */
|
||
|
||
for (i = 0; i < n_sets; i++)
|
||
{
|
||
rtx dest = SET_DEST (sets[i].rtl);
|
||
rtx src = SET_SRC (sets[i].rtl);
|
||
rtx new = canon_reg (src, insn);
|
||
|
||
sets[i].orig_src = src;
|
||
validate_change (insn, &SET_SRC (sets[i].rtl), new, 1);
|
||
|
||
if (GET_CODE (dest) == ZERO_EXTRACT)
|
||
{
|
||
validate_change (insn, &XEXP (dest, 1),
|
||
canon_reg (XEXP (dest, 1), insn), 1);
|
||
validate_change (insn, &XEXP (dest, 2),
|
||
canon_reg (XEXP (dest, 2), insn), 1);
|
||
}
|
||
|
||
while (GET_CODE (dest) == SUBREG
|
||
|| GET_CODE (dest) == ZERO_EXTRACT
|
||
|| GET_CODE (dest) == STRICT_LOW_PART)
|
||
dest = XEXP (dest, 0);
|
||
|
||
if (MEM_P (dest))
|
||
canon_reg (dest, insn);
|
||
}
|
||
|
||
/* Now that we have done all the replacements, we can apply the change
|
||
group and see if they all work. Note that this will cause some
|
||
canonicalizations that would have worked individually not to be applied
|
||
because some other canonicalization didn't work, but this should not
|
||
occur often.
|
||
|
||
The result of apply_change_group can be ignored; see canon_reg. */
|
||
|
||
apply_change_group ();
|
||
|
||
/* Set sets[i].src_elt to the class each source belongs to.
|
||
Detect assignments from or to volatile things
|
||
and set set[i] to zero so they will be ignored
|
||
in the rest of this function.
|
||
|
||
Nothing in this loop changes the hash table or the register chains. */
|
||
|
||
for (i = 0; i < n_sets; i++)
|
||
{
|
||
rtx src, dest;
|
||
rtx src_folded;
|
||
struct table_elt *elt = 0, *p;
|
||
enum machine_mode mode;
|
||
rtx src_eqv_here;
|
||
rtx src_const = 0;
|
||
rtx src_related = 0;
|
||
struct table_elt *src_const_elt = 0;
|
||
int src_cost = MAX_COST;
|
||
int src_eqv_cost = MAX_COST;
|
||
int src_folded_cost = MAX_COST;
|
||
int src_related_cost = MAX_COST;
|
||
int src_elt_cost = MAX_COST;
|
||
int src_regcost = MAX_COST;
|
||
int src_eqv_regcost = MAX_COST;
|
||
int src_folded_regcost = MAX_COST;
|
||
int src_related_regcost = MAX_COST;
|
||
int src_elt_regcost = MAX_COST;
|
||
/* Set nonzero if we need to call force_const_mem on with the
|
||
contents of src_folded before using it. */
|
||
int src_folded_force_flag = 0;
|
||
|
||
dest = SET_DEST (sets[i].rtl);
|
||
src = SET_SRC (sets[i].rtl);
|
||
|
||
/* If SRC is a constant that has no machine mode,
|
||
hash it with the destination's machine mode.
|
||
This way we can keep different modes separate. */
|
||
|
||
mode = GET_MODE (src) == VOIDmode ? GET_MODE (dest) : GET_MODE (src);
|
||
sets[i].mode = mode;
|
||
|
||
if (src_eqv)
|
||
{
|
||
enum machine_mode eqvmode = mode;
|
||
if (GET_CODE (dest) == STRICT_LOW_PART)
|
||
eqvmode = GET_MODE (SUBREG_REG (XEXP (dest, 0)));
|
||
do_not_record = 0;
|
||
hash_arg_in_memory = 0;
|
||
src_eqv_hash = HASH (src_eqv, eqvmode);
|
||
|
||
/* Find the equivalence class for the equivalent expression. */
|
||
|
||
if (!do_not_record)
|
||
src_eqv_elt = lookup (src_eqv, src_eqv_hash, eqvmode);
|
||
|
||
src_eqv_volatile = do_not_record;
|
||
src_eqv_in_memory = hash_arg_in_memory;
|
||
}
|
||
|
||
/* If this is a STRICT_LOW_PART assignment, src_eqv corresponds to the
|
||
value of the INNER register, not the destination. So it is not
|
||
a valid substitution for the source. But save it for later. */
|
||
if (GET_CODE (dest) == STRICT_LOW_PART)
|
||
src_eqv_here = 0;
|
||
else
|
||
src_eqv_here = src_eqv;
|
||
|
||
/* Simplify and foldable subexpressions in SRC. Then get the fully-
|
||
simplified result, which may not necessarily be valid. */
|
||
src_folded = fold_rtx (src, insn);
|
||
|
||
#if 0
|
||
/* ??? This caused bad code to be generated for the m68k port with -O2.
|
||
Suppose src is (CONST_INT -1), and that after truncation src_folded
|
||
is (CONST_INT 3). Suppose src_folded is then used for src_const.
|
||
At the end we will add src and src_const to the same equivalence
|
||
class. We now have 3 and -1 on the same equivalence class. This
|
||
causes later instructions to be mis-optimized. */
|
||
/* If storing a constant in a bitfield, pre-truncate the constant
|
||
so we will be able to record it later. */
|
||
if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT)
|
||
{
|
||
rtx width = XEXP (SET_DEST (sets[i].rtl), 1);
|
||
|
||
if (GET_CODE (src) == CONST_INT
|
||
&& GET_CODE (width) == CONST_INT
|
||
&& INTVAL (width) < HOST_BITS_PER_WIDE_INT
|
||
&& (INTVAL (src) & ((HOST_WIDE_INT) (-1) << INTVAL (width))))
|
||
src_folded
|
||
= GEN_INT (INTVAL (src) & (((HOST_WIDE_INT) 1
|
||
<< INTVAL (width)) - 1));
|
||
}
|
||
#endif
|
||
|
||
/* Compute SRC's hash code, and also notice if it
|
||
should not be recorded at all. In that case,
|
||
prevent any further processing of this assignment. */
|
||
do_not_record = 0;
|
||
hash_arg_in_memory = 0;
|
||
|
||
sets[i].src = src;
|
||
sets[i].src_hash = HASH (src, mode);
|
||
sets[i].src_volatile = do_not_record;
|
||
sets[i].src_in_memory = hash_arg_in_memory;
|
||
|
||
/* If SRC is a MEM, there is a REG_EQUIV note for SRC, and DEST is
|
||
a pseudo, do not record SRC. Using SRC as a replacement for
|
||
anything else will be incorrect in that situation. Note that
|
||
this usually occurs only for stack slots, in which case all the
|
||
RTL would be referring to SRC, so we don't lose any optimization
|
||
opportunities by not having SRC in the hash table. */
|
||
|
||
if (MEM_P (src)
|
||
&& find_reg_note (insn, REG_EQUIV, NULL_RTX) != 0
|
||
&& REG_P (dest)
|
||
&& REGNO (dest) >= FIRST_PSEUDO_REGISTER)
|
||
sets[i].src_volatile = 1;
|
||
|
||
#if 0
|
||
/* It is no longer clear why we used to do this, but it doesn't
|
||
appear to still be needed. So let's try without it since this
|
||
code hurts cse'ing widened ops. */
|
||
/* If source is a paradoxical subreg (such as QI treated as an SI),
|
||
treat it as volatile. It may do the work of an SI in one context
|
||
where the extra bits are not being used, but cannot replace an SI
|
||
in general. */
|
||
if (GET_CODE (src) == SUBREG
|
||
&& (GET_MODE_SIZE (GET_MODE (src))
|
||
> GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))))
|
||
sets[i].src_volatile = 1;
|
||
#endif
|
||
|
||
/* Locate all possible equivalent forms for SRC. Try to replace
|
||
SRC in the insn with each cheaper equivalent.
|
||
|
||
We have the following types of equivalents: SRC itself, a folded
|
||
version, a value given in a REG_EQUAL note, or a value related
|
||
to a constant.
|
||
|
||
Each of these equivalents may be part of an additional class
|
||
of equivalents (if more than one is in the table, they must be in
|
||
the same class; we check for this).
|
||
|
||
If the source is volatile, we don't do any table lookups.
|
||
|
||
We note any constant equivalent for possible later use in a
|
||
REG_NOTE. */
|
||
|
||
if (!sets[i].src_volatile)
|
||
elt = lookup (src, sets[i].src_hash, mode);
|
||
|
||
sets[i].src_elt = elt;
|
||
|
||
if (elt && src_eqv_here && src_eqv_elt)
|
||
{
|
||
if (elt->first_same_value != src_eqv_elt->first_same_value)
|
||
{
|
||
/* The REG_EQUAL is indicating that two formerly distinct
|
||
classes are now equivalent. So merge them. */
|
||
merge_equiv_classes (elt, src_eqv_elt);
|
||
src_eqv_hash = HASH (src_eqv, elt->mode);
|
||
src_eqv_elt = lookup (src_eqv, src_eqv_hash, elt->mode);
|
||
}
|
||
|
||
src_eqv_here = 0;
|
||
}
|
||
|
||
else if (src_eqv_elt)
|
||
elt = src_eqv_elt;
|
||
|
||
/* Try to find a constant somewhere and record it in `src_const'.
|
||
Record its table element, if any, in `src_const_elt'. Look in
|
||
any known equivalences first. (If the constant is not in the
|
||
table, also set `sets[i].src_const_hash'). */
|
||
if (elt)
|
||
for (p = elt->first_same_value; p; p = p->next_same_value)
|
||
if (p->is_const)
|
||
{
|
||
src_const = p->exp;
|
||
src_const_elt = elt;
|
||
break;
|
||
}
|
||
|
||
if (src_const == 0
|
||
&& (CONSTANT_P (src_folded)
|
||
/* Consider (minus (label_ref L1) (label_ref L2)) as
|
||
"constant" here so we will record it. This allows us
|
||
to fold switch statements when an ADDR_DIFF_VEC is used. */
|
||
|| (GET_CODE (src_folded) == MINUS
|
||
&& GET_CODE (XEXP (src_folded, 0)) == LABEL_REF
|
||
&& GET_CODE (XEXP (src_folded, 1)) == LABEL_REF)))
|
||
src_const = src_folded, src_const_elt = elt;
|
||
else if (src_const == 0 && src_eqv_here && CONSTANT_P (src_eqv_here))
|
||
src_const = src_eqv_here, src_const_elt = src_eqv_elt;
|
||
|
||
/* If we don't know if the constant is in the table, get its
|
||
hash code and look it up. */
|
||
if (src_const && src_const_elt == 0)
|
||
{
|
||
sets[i].src_const_hash = HASH (src_const, mode);
|
||
src_const_elt = lookup (src_const, sets[i].src_const_hash, mode);
|
||
}
|
||
|
||
sets[i].src_const = src_const;
|
||
sets[i].src_const_elt = src_const_elt;
|
||
|
||
/* If the constant and our source are both in the table, mark them as
|
||
equivalent. Otherwise, if a constant is in the table but the source
|
||
isn't, set ELT to it. */
|
||
if (src_const_elt && elt
|
||
&& src_const_elt->first_same_value != elt->first_same_value)
|
||
merge_equiv_classes (elt, src_const_elt);
|
||
else if (src_const_elt && elt == 0)
|
||
elt = src_const_elt;
|
||
|
||
/* See if there is a register linearly related to a constant
|
||
equivalent of SRC. */
|
||
if (src_const
|
||
&& (GET_CODE (src_const) == CONST
|
||
|| (src_const_elt && src_const_elt->related_value != 0)))
|
||
{
|
||
src_related = use_related_value (src_const, src_const_elt);
|
||
if (src_related)
|
||
{
|
||
struct table_elt *src_related_elt
|
||
= lookup (src_related, HASH (src_related, mode), mode);
|
||
if (src_related_elt && elt)
|
||
{
|
||
if (elt->first_same_value
|
||
!= src_related_elt->first_same_value)
|
||
/* This can occur when we previously saw a CONST
|
||
involving a SYMBOL_REF and then see the SYMBOL_REF
|
||
twice. Merge the involved classes. */
|
||
merge_equiv_classes (elt, src_related_elt);
|
||
|
||
src_related = 0;
|
||
src_related_elt = 0;
|
||
}
|
||
else if (src_related_elt && elt == 0)
|
||
elt = src_related_elt;
|
||
}
|
||
}
|
||
|
||
/* See if we have a CONST_INT that is already in a register in a
|
||
wider mode. */
|
||
|
||
if (src_const && src_related == 0 && GET_CODE (src_const) == CONST_INT
|
||
&& GET_MODE_CLASS (mode) == MODE_INT
|
||
&& GET_MODE_BITSIZE (mode) < BITS_PER_WORD)
|
||
{
|
||
enum machine_mode wider_mode;
|
||
|
||
for (wider_mode = GET_MODE_WIDER_MODE (mode);
|
||
GET_MODE_BITSIZE (wider_mode) <= BITS_PER_WORD
|
||
&& src_related == 0;
|
||
wider_mode = GET_MODE_WIDER_MODE (wider_mode))
|
||
{
|
||
struct table_elt *const_elt
|
||
= lookup (src_const, HASH (src_const, wider_mode), wider_mode);
|
||
|
||
if (const_elt == 0)
|
||
continue;
|
||
|
||
for (const_elt = const_elt->first_same_value;
|
||
const_elt; const_elt = const_elt->next_same_value)
|
||
if (REG_P (const_elt->exp))
|
||
{
|
||
src_related = gen_lowpart (mode,
|
||
const_elt->exp);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Another possibility is that we have an AND with a constant in
|
||
a mode narrower than a word. If so, it might have been generated
|
||
as part of an "if" which would narrow the AND. If we already
|
||
have done the AND in a wider mode, we can use a SUBREG of that
|
||
value. */
|
||
|
||
if (flag_expensive_optimizations && ! src_related
|
||
&& GET_CODE (src) == AND && GET_CODE (XEXP (src, 1)) == CONST_INT
|
||
&& GET_MODE_SIZE (mode) < UNITS_PER_WORD)
|
||
{
|
||
enum machine_mode tmode;
|
||
rtx new_and = gen_rtx_AND (VOIDmode, NULL_RTX, XEXP (src, 1));
|
||
|
||
for (tmode = GET_MODE_WIDER_MODE (mode);
|
||
GET_MODE_SIZE (tmode) <= UNITS_PER_WORD;
|
||
tmode = GET_MODE_WIDER_MODE (tmode))
|
||
{
|
||
rtx inner = gen_lowpart (tmode, XEXP (src, 0));
|
||
struct table_elt *larger_elt;
|
||
|
||
if (inner)
|
||
{
|
||
PUT_MODE (new_and, tmode);
|
||
XEXP (new_and, 0) = inner;
|
||
larger_elt = lookup (new_and, HASH (new_and, tmode), tmode);
|
||
if (larger_elt == 0)
|
||
continue;
|
||
|
||
for (larger_elt = larger_elt->first_same_value;
|
||
larger_elt; larger_elt = larger_elt->next_same_value)
|
||
if (REG_P (larger_elt->exp))
|
||
{
|
||
src_related
|
||
= gen_lowpart (mode, larger_elt->exp);
|
||
break;
|
||
}
|
||
|
||
if (src_related)
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
#ifdef LOAD_EXTEND_OP
|
||
/* See if a MEM has already been loaded with a widening operation;
|
||
if it has, we can use a subreg of that. Many CISC machines
|
||
also have such operations, but this is only likely to be
|
||
beneficial on these machines. */
|
||
|
||
if (flag_expensive_optimizations && src_related == 0
|
||
&& (GET_MODE_SIZE (mode) < UNITS_PER_WORD)
|
||
&& GET_MODE_CLASS (mode) == MODE_INT
|
||
&& MEM_P (src) && ! do_not_record
|
||
&& LOAD_EXTEND_OP (mode) != UNKNOWN)
|
||
{
|
||
struct rtx_def memory_extend_buf;
|
||
rtx memory_extend_rtx = &memory_extend_buf;
|
||
enum machine_mode tmode;
|
||
|
||
/* Set what we are trying to extend and the operation it might
|
||
have been extended with. */
|
||
memset (memory_extend_rtx, 0, sizeof(*memory_extend_rtx));
|
||
PUT_CODE (memory_extend_rtx, LOAD_EXTEND_OP (mode));
|
||
XEXP (memory_extend_rtx, 0) = src;
|
||
|
||
for (tmode = GET_MODE_WIDER_MODE (mode);
|
||
GET_MODE_SIZE (tmode) <= UNITS_PER_WORD;
|
||
tmode = GET_MODE_WIDER_MODE (tmode))
|
||
{
|
||
struct table_elt *larger_elt;
|
||
|
||
PUT_MODE (memory_extend_rtx, tmode);
|
||
larger_elt = lookup (memory_extend_rtx,
|
||
HASH (memory_extend_rtx, tmode), tmode);
|
||
if (larger_elt == 0)
|
||
continue;
|
||
|
||
for (larger_elt = larger_elt->first_same_value;
|
||
larger_elt; larger_elt = larger_elt->next_same_value)
|
||
if (REG_P (larger_elt->exp))
|
||
{
|
||
src_related = gen_lowpart (mode,
|
||
larger_elt->exp);
|
||
break;
|
||
}
|
||
|
||
if (src_related)
|
||
break;
|
||
}
|
||
}
|
||
#endif /* LOAD_EXTEND_OP */
|
||
|
||
if (src == src_folded)
|
||
src_folded = 0;
|
||
|
||
/* At this point, ELT, if nonzero, points to a class of expressions
|
||
equivalent to the source of this SET and SRC, SRC_EQV, SRC_FOLDED,
|
||
and SRC_RELATED, if nonzero, each contain additional equivalent
|
||
expressions. Prune these latter expressions by deleting expressions
|
||
already in the equivalence class.
|
||
|
||
Check for an equivalent identical to the destination. If found,
|
||
this is the preferred equivalent since it will likely lead to
|
||
elimination of the insn. Indicate this by placing it in
|
||
`src_related'. */
|
||
|
||
if (elt)
|
||
elt = elt->first_same_value;
|
||
for (p = elt; p; p = p->next_same_value)
|
||
{
|
||
enum rtx_code code = GET_CODE (p->exp);
|
||
|
||
/* If the expression is not valid, ignore it. Then we do not
|
||
have to check for validity below. In most cases, we can use
|
||
`rtx_equal_p', since canonicalization has already been done. */
|
||
if (code != REG && ! exp_equiv_p (p->exp, p->exp, 1, false))
|
||
continue;
|
||
|
||
/* Also skip paradoxical subregs, unless that's what we're
|
||
looking for. */
|
||
if (code == SUBREG
|
||
&& (GET_MODE_SIZE (GET_MODE (p->exp))
|
||
> GET_MODE_SIZE (GET_MODE (SUBREG_REG (p->exp))))
|
||
&& ! (src != 0
|
||
&& GET_CODE (src) == SUBREG
|
||
&& GET_MODE (src) == GET_MODE (p->exp)
|
||
&& (GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))
|
||
< GET_MODE_SIZE (GET_MODE (SUBREG_REG (p->exp))))))
|
||
continue;
|
||
|
||
if (src && GET_CODE (src) == code && rtx_equal_p (src, p->exp))
|
||
src = 0;
|
||
else if (src_folded && GET_CODE (src_folded) == code
|
||
&& rtx_equal_p (src_folded, p->exp))
|
||
src_folded = 0;
|
||
else if (src_eqv_here && GET_CODE (src_eqv_here) == code
|
||
&& rtx_equal_p (src_eqv_here, p->exp))
|
||
src_eqv_here = 0;
|
||
else if (src_related && GET_CODE (src_related) == code
|
||
&& rtx_equal_p (src_related, p->exp))
|
||
src_related = 0;
|
||
|
||
/* This is the same as the destination of the insns, we want
|
||
to prefer it. Copy it to src_related. The code below will
|
||
then give it a negative cost. */
|
||
if (GET_CODE (dest) == code && rtx_equal_p (p->exp, dest))
|
||
src_related = dest;
|
||
}
|
||
|
||
/* Find the cheapest valid equivalent, trying all the available
|
||
possibilities. Prefer items not in the hash table to ones
|
||
that are when they are equal cost. Note that we can never
|
||
worsen an insn as the current contents will also succeed.
|
||
If we find an equivalent identical to the destination, use it as best,
|
||
since this insn will probably be eliminated in that case. */
|
||
if (src)
|
||
{
|
||
if (rtx_equal_p (src, dest))
|
||
src_cost = src_regcost = -1;
|
||
else
|
||
{
|
||
src_cost = COST (src);
|
||
src_regcost = approx_reg_cost (src);
|
||
}
|
||
}
|
||
|
||
if (src_eqv_here)
|
||
{
|
||
if (rtx_equal_p (src_eqv_here, dest))
|
||
src_eqv_cost = src_eqv_regcost = -1;
|
||
else
|
||
{
|
||
src_eqv_cost = COST (src_eqv_here);
|
||
src_eqv_regcost = approx_reg_cost (src_eqv_here);
|
||
}
|
||
}
|
||
|
||
if (src_folded)
|
||
{
|
||
if (rtx_equal_p (src_folded, dest))
|
||
src_folded_cost = src_folded_regcost = -1;
|
||
else
|
||
{
|
||
src_folded_cost = COST (src_folded);
|
||
src_folded_regcost = approx_reg_cost (src_folded);
|
||
}
|
||
}
|
||
|
||
if (src_related)
|
||
{
|
||
if (rtx_equal_p (src_related, dest))
|
||
src_related_cost = src_related_regcost = -1;
|
||
else
|
||
{
|
||
src_related_cost = COST (src_related);
|
||
src_related_regcost = approx_reg_cost (src_related);
|
||
}
|
||
}
|
||
|
||
/* If this was an indirect jump insn, a known label will really be
|
||
cheaper even though it looks more expensive. */
|
||
if (dest == pc_rtx && src_const && GET_CODE (src_const) == LABEL_REF)
|
||
src_folded = src_const, src_folded_cost = src_folded_regcost = -1;
|
||
|
||
/* Terminate loop when replacement made. This must terminate since
|
||
the current contents will be tested and will always be valid. */
|
||
while (1)
|
||
{
|
||
rtx trial;
|
||
|
||
/* Skip invalid entries. */
|
||
while (elt && !REG_P (elt->exp)
|
||
&& ! exp_equiv_p (elt->exp, elt->exp, 1, false))
|
||
elt = elt->next_same_value;
|
||
|
||
/* A paradoxical subreg would be bad here: it'll be the right
|
||
size, but later may be adjusted so that the upper bits aren't
|
||
what we want. So reject it. */
|
||
if (elt != 0
|
||
&& GET_CODE (elt->exp) == SUBREG
|
||
&& (GET_MODE_SIZE (GET_MODE (elt->exp))
|
||
> GET_MODE_SIZE (GET_MODE (SUBREG_REG (elt->exp))))
|
||
/* It is okay, though, if the rtx we're trying to match
|
||
will ignore any of the bits we can't predict. */
|
||
&& ! (src != 0
|
||
&& GET_CODE (src) == SUBREG
|
||
&& GET_MODE (src) == GET_MODE (elt->exp)
|
||
&& (GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))
|
||
< GET_MODE_SIZE (GET_MODE (SUBREG_REG (elt->exp))))))
|
||
{
|
||
elt = elt->next_same_value;
|
||
continue;
|
||
}
|
||
|
||
if (elt)
|
||
{
|
||
src_elt_cost = elt->cost;
|
||
src_elt_regcost = elt->regcost;
|
||
}
|
||
|
||
/* Find cheapest and skip it for the next time. For items
|
||
of equal cost, use this order:
|
||
src_folded, src, src_eqv, src_related and hash table entry. */
|
||
if (src_folded
|
||
&& preferable (src_folded_cost, src_folded_regcost,
|
||
src_cost, src_regcost) <= 0
|
||
&& preferable (src_folded_cost, src_folded_regcost,
|
||
src_eqv_cost, src_eqv_regcost) <= 0
|
||
&& preferable (src_folded_cost, src_folded_regcost,
|
||
src_related_cost, src_related_regcost) <= 0
|
||
&& preferable (src_folded_cost, src_folded_regcost,
|
||
src_elt_cost, src_elt_regcost) <= 0)
|
||
{
|
||
trial = src_folded, src_folded_cost = MAX_COST;
|
||
if (src_folded_force_flag)
|
||
{
|
||
rtx forced = force_const_mem (mode, trial);
|
||
if (forced)
|
||
trial = forced;
|
||
}
|
||
}
|
||
else if (src
|
||
&& preferable (src_cost, src_regcost,
|
||
src_eqv_cost, src_eqv_regcost) <= 0
|
||
&& preferable (src_cost, src_regcost,
|
||
src_related_cost, src_related_regcost) <= 0
|
||
&& preferable (src_cost, src_regcost,
|
||
src_elt_cost, src_elt_regcost) <= 0)
|
||
trial = src, src_cost = MAX_COST;
|
||
else if (src_eqv_here
|
||
&& preferable (src_eqv_cost, src_eqv_regcost,
|
||
src_related_cost, src_related_regcost) <= 0
|
||
&& preferable (src_eqv_cost, src_eqv_regcost,
|
||
src_elt_cost, src_elt_regcost) <= 0)
|
||
trial = copy_rtx (src_eqv_here), src_eqv_cost = MAX_COST;
|
||
else if (src_related
|
||
&& preferable (src_related_cost, src_related_regcost,
|
||
src_elt_cost, src_elt_regcost) <= 0)
|
||
trial = copy_rtx (src_related), src_related_cost = MAX_COST;
|
||
else
|
||
{
|
||
trial = copy_rtx (elt->exp);
|
||
elt = elt->next_same_value;
|
||
src_elt_cost = MAX_COST;
|
||
}
|
||
|
||
/* We don't normally have an insn matching (set (pc) (pc)), so
|
||
check for this separately here. We will delete such an
|
||
insn below.
|
||
|
||
For other cases such as a table jump or conditional jump
|
||
where we know the ultimate target, go ahead and replace the
|
||
operand. While that may not make a valid insn, we will
|
||
reemit the jump below (and also insert any necessary
|
||
barriers). */
|
||
if (n_sets == 1 && dest == pc_rtx
|
||
&& (trial == pc_rtx
|
||
|| (GET_CODE (trial) == LABEL_REF
|
||
&& ! condjump_p (insn))))
|
||
{
|
||
/* Don't substitute non-local labels, this confuses CFG. */
|
||
if (GET_CODE (trial) == LABEL_REF
|
||
&& LABEL_REF_NONLOCAL_P (trial))
|
||
continue;
|
||
|
||
SET_SRC (sets[i].rtl) = trial;
|
||
cse_jumps_altered = 1;
|
||
break;
|
||
}
|
||
|
||
/* Reject certain invalid forms of CONST that we create. */
|
||
else if (CONSTANT_P (trial)
|
||
&& GET_CODE (trial) == CONST
|
||
/* Reject cases that will cause decode_rtx_const to
|
||
die. On the alpha when simplifying a switch, we
|
||
get (const (truncate (minus (label_ref)
|
||
(label_ref)))). */
|
||
&& (GET_CODE (XEXP (trial, 0)) == TRUNCATE
|
||
/* Likewise on IA-64, except without the
|
||
truncate. */
|
||
|| (GET_CODE (XEXP (trial, 0)) == MINUS
|
||
&& GET_CODE (XEXP (XEXP (trial, 0), 0)) == LABEL_REF
|
||
&& GET_CODE (XEXP (XEXP (trial, 0), 1)) == LABEL_REF)))
|
||
/* Do nothing for this case. */
|
||
;
|
||
|
||
/* Look for a substitution that makes a valid insn. */
|
||
else if (validate_change (insn, &SET_SRC (sets[i].rtl), trial, 0))
|
||
{
|
||
rtx new = canon_reg (SET_SRC (sets[i].rtl), insn);
|
||
|
||
/* If we just made a substitution inside a libcall, then we
|
||
need to make the same substitution in any notes attached
|
||
to the RETVAL insn. */
|
||
if (libcall_insn
|
||
&& (REG_P (sets[i].orig_src)
|
||
|| GET_CODE (sets[i].orig_src) == SUBREG
|
||
|| MEM_P (sets[i].orig_src)))
|
||
{
|
||
rtx note = find_reg_equal_equiv_note (libcall_insn);
|
||
if (note != 0)
|
||
XEXP (note, 0) = simplify_replace_rtx (XEXP (note, 0),
|
||
sets[i].orig_src,
|
||
copy_rtx (new));
|
||
}
|
||
|
||
/* The result of apply_change_group can be ignored; see
|
||
canon_reg. */
|
||
|
||
validate_change (insn, &SET_SRC (sets[i].rtl), new, 1);
|
||
apply_change_group ();
|
||
break;
|
||
}
|
||
|
||
/* If we previously found constant pool entries for
|
||
constants and this is a constant, try making a
|
||
pool entry. Put it in src_folded unless we already have done
|
||
this since that is where it likely came from. */
|
||
|
||
else if (constant_pool_entries_cost
|
||
&& CONSTANT_P (trial)
|
||
&& (src_folded == 0
|
||
|| (!MEM_P (src_folded)
|
||
&& ! src_folded_force_flag))
|
||
&& GET_MODE_CLASS (mode) != MODE_CC
|
||
&& mode != VOIDmode)
|
||
{
|
||
src_folded_force_flag = 1;
|
||
src_folded = trial;
|
||
src_folded_cost = constant_pool_entries_cost;
|
||
src_folded_regcost = constant_pool_entries_regcost;
|
||
}
|
||
}
|
||
|
||
src = SET_SRC (sets[i].rtl);
|
||
|
||
/* In general, it is good to have a SET with SET_SRC == SET_DEST.
|
||
However, there is an important exception: If both are registers
|
||
that are not the head of their equivalence class, replace SET_SRC
|
||
with the head of the class. If we do not do this, we will have
|
||
both registers live over a portion of the basic block. This way,
|
||
their lifetimes will likely abut instead of overlapping. */
|
||
if (REG_P (dest)
|
||
&& REGNO_QTY_VALID_P (REGNO (dest)))
|
||
{
|
||
int dest_q = REG_QTY (REGNO (dest));
|
||
struct qty_table_elem *dest_ent = &qty_table[dest_q];
|
||
|
||
if (dest_ent->mode == GET_MODE (dest)
|
||
&& dest_ent->first_reg != REGNO (dest)
|
||
&& REG_P (src) && REGNO (src) == REGNO (dest)
|
||
/* Don't do this if the original insn had a hard reg as
|
||
SET_SRC or SET_DEST. */
|
||
&& (!REG_P (sets[i].src)
|
||
|| REGNO (sets[i].src) >= FIRST_PSEUDO_REGISTER)
|
||
&& (!REG_P (dest) || REGNO (dest) >= FIRST_PSEUDO_REGISTER))
|
||
/* We can't call canon_reg here because it won't do anything if
|
||
SRC is a hard register. */
|
||
{
|
||
int src_q = REG_QTY (REGNO (src));
|
||
struct qty_table_elem *src_ent = &qty_table[src_q];
|
||
int first = src_ent->first_reg;
|
||
rtx new_src
|
||
= (first >= FIRST_PSEUDO_REGISTER
|
||
? regno_reg_rtx[first] : gen_rtx_REG (GET_MODE (src), first));
|
||
|
||
/* We must use validate-change even for this, because this
|
||
might be a special no-op instruction, suitable only to
|
||
tag notes onto. */
|
||
if (validate_change (insn, &SET_SRC (sets[i].rtl), new_src, 0))
|
||
{
|
||
src = new_src;
|
||
/* If we had a constant that is cheaper than what we are now
|
||
setting SRC to, use that constant. We ignored it when we
|
||
thought we could make this into a no-op. */
|
||
if (src_const && COST (src_const) < COST (src)
|
||
&& validate_change (insn, &SET_SRC (sets[i].rtl),
|
||
src_const, 0))
|
||
src = src_const;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If we made a change, recompute SRC values. */
|
||
if (src != sets[i].src)
|
||
{
|
||
cse_altered = 1;
|
||
do_not_record = 0;
|
||
hash_arg_in_memory = 0;
|
||
sets[i].src = src;
|
||
sets[i].src_hash = HASH (src, mode);
|
||
sets[i].src_volatile = do_not_record;
|
||
sets[i].src_in_memory = hash_arg_in_memory;
|
||
sets[i].src_elt = lookup (src, sets[i].src_hash, mode);
|
||
}
|
||
|
||
/* If this is a single SET, we are setting a register, and we have an
|
||
equivalent constant, we want to add a REG_NOTE. We don't want
|
||
to write a REG_EQUAL note for a constant pseudo since verifying that
|
||
that pseudo hasn't been eliminated is a pain. Such a note also
|
||
won't help anything.
|
||
|
||
Avoid a REG_EQUAL note for (CONST (MINUS (LABEL_REF) (LABEL_REF)))
|
||
which can be created for a reference to a compile time computable
|
||
entry in a jump table. */
|
||
|
||
if (n_sets == 1 && src_const && REG_P (dest)
|
||
&& !REG_P (src_const)
|
||
&& ! (GET_CODE (src_const) == CONST
|
||
&& GET_CODE (XEXP (src_const, 0)) == MINUS
|
||
&& GET_CODE (XEXP (XEXP (src_const, 0), 0)) == LABEL_REF
|
||
&& GET_CODE (XEXP (XEXP (src_const, 0), 1)) == LABEL_REF))
|
||
{
|
||
/* We only want a REG_EQUAL note if src_const != src. */
|
||
if (! rtx_equal_p (src, src_const))
|
||
{
|
||
/* Make sure that the rtx is not shared. */
|
||
src_const = copy_rtx (src_const);
|
||
|
||
/* Record the actual constant value in a REG_EQUAL note,
|
||
making a new one if one does not already exist. */
|
||
set_unique_reg_note (insn, REG_EQUAL, src_const);
|
||
}
|
||
}
|
||
|
||
/* Now deal with the destination. */
|
||
do_not_record = 0;
|
||
|
||
/* Look within any ZERO_EXTRACT to the MEM or REG within it. */
|
||
while (GET_CODE (dest) == SUBREG
|
||
|| GET_CODE (dest) == ZERO_EXTRACT
|
||
|| GET_CODE (dest) == STRICT_LOW_PART)
|
||
dest = XEXP (dest, 0);
|
||
|
||
sets[i].inner_dest = dest;
|
||
|
||
if (MEM_P (dest))
|
||
{
|
||
#ifdef PUSH_ROUNDING
|
||
/* Stack pushes invalidate the stack pointer. */
|
||
rtx addr = XEXP (dest, 0);
|
||
if (GET_RTX_CLASS (GET_CODE (addr)) == RTX_AUTOINC
|
||
&& XEXP (addr, 0) == stack_pointer_rtx)
|
||
invalidate (stack_pointer_rtx, VOIDmode);
|
||
#endif
|
||
dest = fold_rtx (dest, insn);
|
||
}
|
||
|
||
/* Compute the hash code of the destination now,
|
||
before the effects of this instruction are recorded,
|
||
since the register values used in the address computation
|
||
are those before this instruction. */
|
||
sets[i].dest_hash = HASH (dest, mode);
|
||
|
||
/* Don't enter a bit-field in the hash table
|
||
because the value in it after the store
|
||
may not equal what was stored, due to truncation. */
|
||
|
||
if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT)
|
||
{
|
||
rtx width = XEXP (SET_DEST (sets[i].rtl), 1);
|
||
|
||
if (src_const != 0 && GET_CODE (src_const) == CONST_INT
|
||
&& GET_CODE (width) == CONST_INT
|
||
&& INTVAL (width) < HOST_BITS_PER_WIDE_INT
|
||
&& ! (INTVAL (src_const)
|
||
& ((HOST_WIDE_INT) (-1) << INTVAL (width))))
|
||
/* Exception: if the value is constant,
|
||
and it won't be truncated, record it. */
|
||
;
|
||
else
|
||
{
|
||
/* This is chosen so that the destination will be invalidated
|
||
but no new value will be recorded.
|
||
We must invalidate because sometimes constant
|
||
values can be recorded for bitfields. */
|
||
sets[i].src_elt = 0;
|
||
sets[i].src_volatile = 1;
|
||
src_eqv = 0;
|
||
src_eqv_elt = 0;
|
||
}
|
||
}
|
||
|
||
/* If only one set in a JUMP_INSN and it is now a no-op, we can delete
|
||
the insn. */
|
||
else if (n_sets == 1 && dest == pc_rtx && src == pc_rtx)
|
||
{
|
||
/* One less use of the label this insn used to jump to. */
|
||
delete_insn (insn);
|
||
cse_jumps_altered = 1;
|
||
/* No more processing for this set. */
|
||
sets[i].rtl = 0;
|
||
}
|
||
|
||
/* If this SET is now setting PC to a label, we know it used to
|
||
be a conditional or computed branch. */
|
||
else if (dest == pc_rtx && GET_CODE (src) == LABEL_REF
|
||
&& !LABEL_REF_NONLOCAL_P (src))
|
||
{
|
||
/* Now emit a BARRIER after the unconditional jump. */
|
||
if (NEXT_INSN (insn) == 0
|
||
|| !BARRIER_P (NEXT_INSN (insn)))
|
||
emit_barrier_after (insn);
|
||
|
||
/* We reemit the jump in as many cases as possible just in
|
||
case the form of an unconditional jump is significantly
|
||
different than a computed jump or conditional jump.
|
||
|
||
If this insn has multiple sets, then reemitting the
|
||
jump is nontrivial. So instead we just force rerecognition
|
||
and hope for the best. */
|
||
if (n_sets == 1)
|
||
{
|
||
rtx new, note;
|
||
|
||
new = emit_jump_insn_after (gen_jump (XEXP (src, 0)), insn);
|
||
JUMP_LABEL (new) = XEXP (src, 0);
|
||
LABEL_NUSES (XEXP (src, 0))++;
|
||
|
||
/* Make sure to copy over REG_NON_LOCAL_GOTO. */
|
||
note = find_reg_note (insn, REG_NON_LOCAL_GOTO, 0);
|
||
if (note)
|
||
{
|
||
XEXP (note, 1) = NULL_RTX;
|
||
REG_NOTES (new) = note;
|
||
}
|
||
|
||
delete_insn (insn);
|
||
insn = new;
|
||
|
||
/* Now emit a BARRIER after the unconditional jump. */
|
||
if (NEXT_INSN (insn) == 0
|
||
|| !BARRIER_P (NEXT_INSN (insn)))
|
||
emit_barrier_after (insn);
|
||
}
|
||
else
|
||
INSN_CODE (insn) = -1;
|
||
|
||
/* Do not bother deleting any unreachable code,
|
||
let jump/flow do that. */
|
||
|
||
cse_jumps_altered = 1;
|
||
sets[i].rtl = 0;
|
||
}
|
||
|
||
/* If destination is volatile, invalidate it and then do no further
|
||
processing for this assignment. */
|
||
|
||
else if (do_not_record)
|
||
{
|
||
if (REG_P (dest) || GET_CODE (dest) == SUBREG)
|
||
invalidate (dest, VOIDmode);
|
||
else if (MEM_P (dest))
|
||
invalidate (dest, VOIDmode);
|
||
else if (GET_CODE (dest) == STRICT_LOW_PART
|
||
|| GET_CODE (dest) == ZERO_EXTRACT)
|
||
invalidate (XEXP (dest, 0), GET_MODE (dest));
|
||
sets[i].rtl = 0;
|
||
}
|
||
|
||
if (sets[i].rtl != 0 && dest != SET_DEST (sets[i].rtl))
|
||
sets[i].dest_hash = HASH (SET_DEST (sets[i].rtl), mode);
|
||
|
||
#ifdef HAVE_cc0
|
||
/* If setting CC0, record what it was set to, or a constant, if it
|
||
is equivalent to a constant. If it is being set to a floating-point
|
||
value, make a COMPARE with the appropriate constant of 0. If we
|
||
don't do this, later code can interpret this as a test against
|
||
const0_rtx, which can cause problems if we try to put it into an
|
||
insn as a floating-point operand. */
|
||
if (dest == cc0_rtx)
|
||
{
|
||
this_insn_cc0 = src_const && mode != VOIDmode ? src_const : src;
|
||
this_insn_cc0_mode = mode;
|
||
if (FLOAT_MODE_P (mode))
|
||
this_insn_cc0 = gen_rtx_COMPARE (VOIDmode, this_insn_cc0,
|
||
CONST0_RTX (mode));
|
||
}
|
||
#endif
|
||
}
|
||
|
||
/* Now enter all non-volatile source expressions in the hash table
|
||
if they are not already present.
|
||
Record their equivalence classes in src_elt.
|
||
This way we can insert the corresponding destinations into
|
||
the same classes even if the actual sources are no longer in them
|
||
(having been invalidated). */
|
||
|
||
if (src_eqv && src_eqv_elt == 0 && sets[0].rtl != 0 && ! src_eqv_volatile
|
||
&& ! rtx_equal_p (src_eqv, SET_DEST (sets[0].rtl)))
|
||
{
|
||
struct table_elt *elt;
|
||
struct table_elt *classp = sets[0].src_elt;
|
||
rtx dest = SET_DEST (sets[0].rtl);
|
||
enum machine_mode eqvmode = GET_MODE (dest);
|
||
|
||
if (GET_CODE (dest) == STRICT_LOW_PART)
|
||
{
|
||
eqvmode = GET_MODE (SUBREG_REG (XEXP (dest, 0)));
|
||
classp = 0;
|
||
}
|
||
if (insert_regs (src_eqv, classp, 0))
|
||
{
|
||
rehash_using_reg (src_eqv);
|
||
src_eqv_hash = HASH (src_eqv, eqvmode);
|
||
}
|
||
elt = insert (src_eqv, classp, src_eqv_hash, eqvmode);
|
||
elt->in_memory = src_eqv_in_memory;
|
||
src_eqv_elt = elt;
|
||
|
||
/* Check to see if src_eqv_elt is the same as a set source which
|
||
does not yet have an elt, and if so set the elt of the set source
|
||
to src_eqv_elt. */
|
||
for (i = 0; i < n_sets; i++)
|
||
if (sets[i].rtl && sets[i].src_elt == 0
|
||
&& rtx_equal_p (SET_SRC (sets[i].rtl), src_eqv))
|
||
sets[i].src_elt = src_eqv_elt;
|
||
}
|
||
|
||
for (i = 0; i < n_sets; i++)
|
||
if (sets[i].rtl && ! sets[i].src_volatile
|
||
&& ! rtx_equal_p (SET_SRC (sets[i].rtl), SET_DEST (sets[i].rtl)))
|
||
{
|
||
if (GET_CODE (SET_DEST (sets[i].rtl)) == STRICT_LOW_PART)
|
||
{
|
||
/* REG_EQUAL in setting a STRICT_LOW_PART
|
||
gives an equivalent for the entire destination register,
|
||
not just for the subreg being stored in now.
|
||
This is a more interesting equivalence, so we arrange later
|
||
to treat the entire reg as the destination. */
|
||
sets[i].src_elt = src_eqv_elt;
|
||
sets[i].src_hash = src_eqv_hash;
|
||
}
|
||
else
|
||
{
|
||
/* Insert source and constant equivalent into hash table, if not
|
||
already present. */
|
||
struct table_elt *classp = src_eqv_elt;
|
||
rtx src = sets[i].src;
|
||
rtx dest = SET_DEST (sets[i].rtl);
|
||
enum machine_mode mode
|
||
= GET_MODE (src) == VOIDmode ? GET_MODE (dest) : GET_MODE (src);
|
||
|
||
/* It's possible that we have a source value known to be
|
||
constant but don't have a REG_EQUAL note on the insn.
|
||
Lack of a note will mean src_eqv_elt will be NULL. This
|
||
can happen where we've generated a SUBREG to access a
|
||
CONST_INT that is already in a register in a wider mode.
|
||
Ensure that the source expression is put in the proper
|
||
constant class. */
|
||
if (!classp)
|
||
classp = sets[i].src_const_elt;
|
||
|
||
if (sets[i].src_elt == 0)
|
||
{
|
||
/* Don't put a hard register source into the table if this is
|
||
the last insn of a libcall. In this case, we only need
|
||
to put src_eqv_elt in src_elt. */
|
||
if (! find_reg_note (insn, REG_RETVAL, NULL_RTX))
|
||
{
|
||
struct table_elt *elt;
|
||
|
||
/* Note that these insert_regs calls cannot remove
|
||
any of the src_elt's, because they would have failed to
|
||
match if not still valid. */
|
||
if (insert_regs (src, classp, 0))
|
||
{
|
||
rehash_using_reg (src);
|
||
sets[i].src_hash = HASH (src, mode);
|
||
}
|
||
elt = insert (src, classp, sets[i].src_hash, mode);
|
||
elt->in_memory = sets[i].src_in_memory;
|
||
sets[i].src_elt = classp = elt;
|
||
}
|
||
else
|
||
sets[i].src_elt = classp;
|
||
}
|
||
if (sets[i].src_const && sets[i].src_const_elt == 0
|
||
&& src != sets[i].src_const
|
||
&& ! rtx_equal_p (sets[i].src_const, src))
|
||
sets[i].src_elt = insert (sets[i].src_const, classp,
|
||
sets[i].src_const_hash, mode);
|
||
}
|
||
}
|
||
else if (sets[i].src_elt == 0)
|
||
/* If we did not insert the source into the hash table (e.g., it was
|
||
volatile), note the equivalence class for the REG_EQUAL value, if any,
|
||
so that the destination goes into that class. */
|
||
sets[i].src_elt = src_eqv_elt;
|
||
|
||
/* Record destination addresses in the hash table. This allows us to
|
||
check if they are invalidated by other sets. */
|
||
for (i = 0; i < n_sets; i++)
|
||
{
|
||
if (sets[i].rtl)
|
||
{
|
||
rtx x = sets[i].inner_dest;
|
||
struct table_elt *elt;
|
||
enum machine_mode mode;
|
||
unsigned hash;
|
||
|
||
if (MEM_P (x))
|
||
{
|
||
x = XEXP (x, 0);
|
||
mode = GET_MODE (x);
|
||
hash = HASH (x, mode);
|
||
elt = lookup (x, hash, mode);
|
||
if (!elt)
|
||
{
|
||
if (insert_regs (x, NULL, 0))
|
||
{
|
||
rtx dest = SET_DEST (sets[i].rtl);
|
||
|
||
rehash_using_reg (x);
|
||
hash = HASH (x, mode);
|
||
sets[i].dest_hash = HASH (dest, GET_MODE (dest));
|
||
}
|
||
elt = insert (x, NULL, hash, mode);
|
||
}
|
||
|
||
sets[i].dest_addr_elt = elt;
|
||
}
|
||
else
|
||
sets[i].dest_addr_elt = NULL;
|
||
}
|
||
}
|
||
|
||
invalidate_from_clobbers (x);
|
||
|
||
/* Some registers are invalidated by subroutine calls. Memory is
|
||
invalidated by non-constant calls. */
|
||
|
||
if (CALL_P (insn))
|
||
{
|
||
if (! CONST_OR_PURE_CALL_P (insn))
|
||
invalidate_memory ();
|
||
invalidate_for_call ();
|
||
}
|
||
|
||
/* Now invalidate everything set by this instruction.
|
||
If a SUBREG or other funny destination is being set,
|
||
sets[i].rtl is still nonzero, so here we invalidate the reg
|
||
a part of which is being set. */
|
||
|
||
for (i = 0; i < n_sets; i++)
|
||
if (sets[i].rtl)
|
||
{
|
||
/* We can't use the inner dest, because the mode associated with
|
||
a ZERO_EXTRACT is significant. */
|
||
rtx dest = SET_DEST (sets[i].rtl);
|
||
|
||
/* Needed for registers to remove the register from its
|
||
previous quantity's chain.
|
||
Needed for memory if this is a nonvarying address, unless
|
||
we have just done an invalidate_memory that covers even those. */
|
||
if (REG_P (dest) || GET_CODE (dest) == SUBREG)
|
||
invalidate (dest, VOIDmode);
|
||
else if (MEM_P (dest))
|
||
invalidate (dest, VOIDmode);
|
||
else if (GET_CODE (dest) == STRICT_LOW_PART
|
||
|| GET_CODE (dest) == ZERO_EXTRACT)
|
||
invalidate (XEXP (dest, 0), GET_MODE (dest));
|
||
}
|
||
|
||
/* A volatile ASM invalidates everything. */
|
||
if (NONJUMP_INSN_P (insn)
|
||
&& GET_CODE (PATTERN (insn)) == ASM_OPERANDS
|
||
&& MEM_VOLATILE_P (PATTERN (insn)))
|
||
flush_hash_table ();
|
||
|
||
/* Make sure registers mentioned in destinations
|
||
are safe for use in an expression to be inserted.
|
||
This removes from the hash table
|
||
any invalid entry that refers to one of these registers.
|
||
|
||
We don't care about the return value from mention_regs because
|
||
we are going to hash the SET_DEST values unconditionally. */
|
||
|
||
for (i = 0; i < n_sets; i++)
|
||
{
|
||
if (sets[i].rtl)
|
||
{
|
||
rtx x = SET_DEST (sets[i].rtl);
|
||
|
||
if (!REG_P (x))
|
||
mention_regs (x);
|
||
else
|
||
{
|
||
/* We used to rely on all references to a register becoming
|
||
inaccessible when a register changes to a new quantity,
|
||
since that changes the hash code. However, that is not
|
||
safe, since after HASH_SIZE new quantities we get a
|
||
hash 'collision' of a register with its own invalid
|
||
entries. And since SUBREGs have been changed not to
|
||
change their hash code with the hash code of the register,
|
||
it wouldn't work any longer at all. So we have to check
|
||
for any invalid references lying around now.
|
||
This code is similar to the REG case in mention_regs,
|
||
but it knows that reg_tick has been incremented, and
|
||
it leaves reg_in_table as -1 . */
|
||
unsigned int regno = REGNO (x);
|
||
unsigned int endregno
|
||
= regno + (regno >= FIRST_PSEUDO_REGISTER ? 1
|
||
: hard_regno_nregs[regno][GET_MODE (x)]);
|
||
unsigned int i;
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
{
|
||
if (REG_IN_TABLE (i) >= 0)
|
||
{
|
||
remove_invalid_refs (i);
|
||
REG_IN_TABLE (i) = -1;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* We may have just removed some of the src_elt's from the hash table.
|
||
So replace each one with the current head of the same class.
|
||
Also check if destination addresses have been removed. */
|
||
|
||
for (i = 0; i < n_sets; i++)
|
||
if (sets[i].rtl)
|
||
{
|
||
if (sets[i].dest_addr_elt
|
||
&& sets[i].dest_addr_elt->first_same_value == 0)
|
||
{
|
||
/* The elt was removed, which means this destination is not
|
||
valid after this instruction. */
|
||
sets[i].rtl = NULL_RTX;
|
||
}
|
||
else if (sets[i].src_elt && sets[i].src_elt->first_same_value == 0)
|
||
/* If elt was removed, find current head of same class,
|
||
or 0 if nothing remains of that class. */
|
||
{
|
||
struct table_elt *elt = sets[i].src_elt;
|
||
|
||
while (elt && elt->prev_same_value)
|
||
elt = elt->prev_same_value;
|
||
|
||
while (elt && elt->first_same_value == 0)
|
||
elt = elt->next_same_value;
|
||
sets[i].src_elt = elt ? elt->first_same_value : 0;
|
||
}
|
||
}
|
||
|
||
/* Now insert the destinations into their equivalence classes. */
|
||
|
||
for (i = 0; i < n_sets; i++)
|
||
if (sets[i].rtl)
|
||
{
|
||
rtx dest = SET_DEST (sets[i].rtl);
|
||
struct table_elt *elt;
|
||
|
||
/* Don't record value if we are not supposed to risk allocating
|
||
floating-point values in registers that might be wider than
|
||
memory. */
|
||
if ((flag_float_store
|
||
&& MEM_P (dest)
|
||
&& FLOAT_MODE_P (GET_MODE (dest)))
|
||
/* Don't record BLKmode values, because we don't know the
|
||
size of it, and can't be sure that other BLKmode values
|
||
have the same or smaller size. */
|
||
|| GET_MODE (dest) == BLKmode
|
||
/* Don't record values of destinations set inside a libcall block
|
||
since we might delete the libcall. Things should have been set
|
||
up so we won't want to reuse such a value, but we play it safe
|
||
here. */
|
||
|| libcall_insn
|
||
/* If we didn't put a REG_EQUAL value or a source into the hash
|
||
table, there is no point is recording DEST. */
|
||
|| sets[i].src_elt == 0
|
||
/* If DEST is a paradoxical SUBREG and SRC is a ZERO_EXTEND
|
||
or SIGN_EXTEND, don't record DEST since it can cause
|
||
some tracking to be wrong.
|
||
|
||
??? Think about this more later. */
|
||
|| (GET_CODE (dest) == SUBREG
|
||
&& (GET_MODE_SIZE (GET_MODE (dest))
|
||
> GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))))
|
||
&& (GET_CODE (sets[i].src) == SIGN_EXTEND
|
||
|| GET_CODE (sets[i].src) == ZERO_EXTEND)))
|
||
continue;
|
||
|
||
/* STRICT_LOW_PART isn't part of the value BEING set,
|
||
and neither is the SUBREG inside it.
|
||
Note that in this case SETS[I].SRC_ELT is really SRC_EQV_ELT. */
|
||
if (GET_CODE (dest) == STRICT_LOW_PART)
|
||
dest = SUBREG_REG (XEXP (dest, 0));
|
||
|
||
if (REG_P (dest) || GET_CODE (dest) == SUBREG)
|
||
/* Registers must also be inserted into chains for quantities. */
|
||
if (insert_regs (dest, sets[i].src_elt, 1))
|
||
{
|
||
/* If `insert_regs' changes something, the hash code must be
|
||
recalculated. */
|
||
rehash_using_reg (dest);
|
||
sets[i].dest_hash = HASH (dest, GET_MODE (dest));
|
||
}
|
||
|
||
elt = insert (dest, sets[i].src_elt,
|
||
sets[i].dest_hash, GET_MODE (dest));
|
||
|
||
elt->in_memory = (MEM_P (sets[i].inner_dest)
|
||
&& !MEM_READONLY_P (sets[i].inner_dest));
|
||
|
||
/* If we have (set (subreg:m1 (reg:m2 foo) 0) (bar:m1)), M1 is no
|
||
narrower than M2, and both M1 and M2 are the same number of words,
|
||
we are also doing (set (reg:m2 foo) (subreg:m2 (bar:m1) 0)) so
|
||
make that equivalence as well.
|
||
|
||
However, BAR may have equivalences for which gen_lowpart
|
||
will produce a simpler value than gen_lowpart applied to
|
||
BAR (e.g., if BAR was ZERO_EXTENDed from M2), so we will scan all
|
||
BAR's equivalences. If we don't get a simplified form, make
|
||
the SUBREG. It will not be used in an equivalence, but will
|
||
cause two similar assignments to be detected.
|
||
|
||
Note the loop below will find SUBREG_REG (DEST) since we have
|
||
already entered SRC and DEST of the SET in the table. */
|
||
|
||
if (GET_CODE (dest) == SUBREG
|
||
&& (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))) - 1)
|
||
/ UNITS_PER_WORD)
|
||
== (GET_MODE_SIZE (GET_MODE (dest)) - 1) / UNITS_PER_WORD)
|
||
&& (GET_MODE_SIZE (GET_MODE (dest))
|
||
>= GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))))
|
||
&& sets[i].src_elt != 0)
|
||
{
|
||
enum machine_mode new_mode = GET_MODE (SUBREG_REG (dest));
|
||
struct table_elt *elt, *classp = 0;
|
||
|
||
for (elt = sets[i].src_elt->first_same_value; elt;
|
||
elt = elt->next_same_value)
|
||
{
|
||
rtx new_src = 0;
|
||
unsigned src_hash;
|
||
struct table_elt *src_elt;
|
||
int byte = 0;
|
||
|
||
/* Ignore invalid entries. */
|
||
if (!REG_P (elt->exp)
|
||
&& ! exp_equiv_p (elt->exp, elt->exp, 1, false))
|
||
continue;
|
||
|
||
/* We may have already been playing subreg games. If the
|
||
mode is already correct for the destination, use it. */
|
||
if (GET_MODE (elt->exp) == new_mode)
|
||
new_src = elt->exp;
|
||
else
|
||
{
|
||
/* Calculate big endian correction for the SUBREG_BYTE.
|
||
We have already checked that M1 (GET_MODE (dest))
|
||
is not narrower than M2 (new_mode). */
|
||
if (BYTES_BIG_ENDIAN)
|
||
byte = (GET_MODE_SIZE (GET_MODE (dest))
|
||
- GET_MODE_SIZE (new_mode));
|
||
|
||
new_src = simplify_gen_subreg (new_mode, elt->exp,
|
||
GET_MODE (dest), byte);
|
||
}
|
||
|
||
/* The call to simplify_gen_subreg fails if the value
|
||
is VOIDmode, yet we can't do any simplification, e.g.
|
||
for EXPR_LISTs denoting function call results.
|
||
It is invalid to construct a SUBREG with a VOIDmode
|
||
SUBREG_REG, hence a zero new_src means we can't do
|
||
this substitution. */
|
||
if (! new_src)
|
||
continue;
|
||
|
||
src_hash = HASH (new_src, new_mode);
|
||
src_elt = lookup (new_src, src_hash, new_mode);
|
||
|
||
/* Put the new source in the hash table is if isn't
|
||
already. */
|
||
if (src_elt == 0)
|
||
{
|
||
if (insert_regs (new_src, classp, 0))
|
||
{
|
||
rehash_using_reg (new_src);
|
||
src_hash = HASH (new_src, new_mode);
|
||
}
|
||
src_elt = insert (new_src, classp, src_hash, new_mode);
|
||
src_elt->in_memory = elt->in_memory;
|
||
}
|
||
else if (classp && classp != src_elt->first_same_value)
|
||
/* Show that two things that we've seen before are
|
||
actually the same. */
|
||
merge_equiv_classes (src_elt, classp);
|
||
|
||
classp = src_elt->first_same_value;
|
||
/* Ignore invalid entries. */
|
||
while (classp
|
||
&& !REG_P (classp->exp)
|
||
&& ! exp_equiv_p (classp->exp, classp->exp, 1, false))
|
||
classp = classp->next_same_value;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Special handling for (set REG0 REG1) where REG0 is the
|
||
"cheapest", cheaper than REG1. After cse, REG1 will probably not
|
||
be used in the sequel, so (if easily done) change this insn to
|
||
(set REG1 REG0) and replace REG1 with REG0 in the previous insn
|
||
that computed their value. Then REG1 will become a dead store
|
||
and won't cloud the situation for later optimizations.
|
||
|
||
Do not make this change if REG1 is a hard register, because it will
|
||
then be used in the sequel and we may be changing a two-operand insn
|
||
into a three-operand insn.
|
||
|
||
Also do not do this if we are operating on a copy of INSN.
|
||
|
||
Also don't do this if INSN ends a libcall; this would cause an unrelated
|
||
register to be set in the middle of a libcall, and we then get bad code
|
||
if the libcall is deleted. */
|
||
|
||
if (n_sets == 1 && sets[0].rtl && REG_P (SET_DEST (sets[0].rtl))
|
||
&& NEXT_INSN (PREV_INSN (insn)) == insn
|
||
&& REG_P (SET_SRC (sets[0].rtl))
|
||
&& REGNO (SET_SRC (sets[0].rtl)) >= FIRST_PSEUDO_REGISTER
|
||
&& REGNO_QTY_VALID_P (REGNO (SET_SRC (sets[0].rtl))))
|
||
{
|
||
int src_q = REG_QTY (REGNO (SET_SRC (sets[0].rtl)));
|
||
struct qty_table_elem *src_ent = &qty_table[src_q];
|
||
|
||
if ((src_ent->first_reg == REGNO (SET_DEST (sets[0].rtl)))
|
||
&& ! find_reg_note (insn, REG_RETVAL, NULL_RTX))
|
||
{
|
||
rtx prev = insn;
|
||
/* Scan for the previous nonnote insn, but stop at a basic
|
||
block boundary. */
|
||
do
|
||
{
|
||
prev = PREV_INSN (prev);
|
||
}
|
||
while (prev && NOTE_P (prev)
|
||
&& NOTE_LINE_NUMBER (prev) != NOTE_INSN_BASIC_BLOCK);
|
||
|
||
/* Do not swap the registers around if the previous instruction
|
||
attaches a REG_EQUIV note to REG1.
|
||
|
||
??? It's not entirely clear whether we can transfer a REG_EQUIV
|
||
from the pseudo that originally shadowed an incoming argument
|
||
to another register. Some uses of REG_EQUIV might rely on it
|
||
being attached to REG1 rather than REG2.
|
||
|
||
This section previously turned the REG_EQUIV into a REG_EQUAL
|
||
note. We cannot do that because REG_EQUIV may provide an
|
||
uninitialized stack slot when REG_PARM_STACK_SPACE is used. */
|
||
|
||
if (prev != 0 && NONJUMP_INSN_P (prev)
|
||
&& GET_CODE (PATTERN (prev)) == SET
|
||
&& SET_DEST (PATTERN (prev)) == SET_SRC (sets[0].rtl)
|
||
&& ! find_reg_note (prev, REG_EQUIV, NULL_RTX))
|
||
{
|
||
rtx dest = SET_DEST (sets[0].rtl);
|
||
rtx src = SET_SRC (sets[0].rtl);
|
||
rtx note;
|
||
|
||
validate_change (prev, &SET_DEST (PATTERN (prev)), dest, 1);
|
||
validate_change (insn, &SET_DEST (sets[0].rtl), src, 1);
|
||
validate_change (insn, &SET_SRC (sets[0].rtl), dest, 1);
|
||
apply_change_group ();
|
||
|
||
/* If INSN has a REG_EQUAL note, and this note mentions
|
||
REG0, then we must delete it, because the value in
|
||
REG0 has changed. If the note's value is REG1, we must
|
||
also delete it because that is now this insn's dest. */
|
||
note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
|
||
if (note != 0
|
||
&& (reg_mentioned_p (dest, XEXP (note, 0))
|
||
|| rtx_equal_p (src, XEXP (note, 0))))
|
||
remove_note (insn, note);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If this is a conditional jump insn, record any known equivalences due to
|
||
the condition being tested. */
|
||
|
||
if (JUMP_P (insn)
|
||
&& n_sets == 1 && GET_CODE (x) == SET
|
||
&& GET_CODE (SET_SRC (x)) == IF_THEN_ELSE)
|
||
record_jump_equiv (insn, 0);
|
||
|
||
#ifdef HAVE_cc0
|
||
/* If the previous insn set CC0 and this insn no longer references CC0,
|
||
delete the previous insn. Here we use the fact that nothing expects CC0
|
||
to be valid over an insn, which is true until the final pass. */
|
||
if (prev_insn && NONJUMP_INSN_P (prev_insn)
|
||
&& (tem = single_set (prev_insn)) != 0
|
||
&& SET_DEST (tem) == cc0_rtx
|
||
&& ! reg_mentioned_p (cc0_rtx, x))
|
||
delete_insn (prev_insn);
|
||
|
||
prev_insn_cc0 = this_insn_cc0;
|
||
prev_insn_cc0_mode = this_insn_cc0_mode;
|
||
prev_insn = insn;
|
||
#endif
|
||
}
|
||
|
||
/* Remove from the hash table all expressions that reference memory. */
|
||
|
||
static void
|
||
invalidate_memory (void)
|
||
{
|
||
int i;
|
||
struct table_elt *p, *next;
|
||
|
||
for (i = 0; i < HASH_SIZE; i++)
|
||
for (p = table[i]; p; p = next)
|
||
{
|
||
next = p->next_same_hash;
|
||
if (p->in_memory)
|
||
remove_from_table (p, i);
|
||
}
|
||
}
|
||
|
||
/* If ADDR is an address that implicitly affects the stack pointer, return
|
||
1 and update the register tables to show the effect. Else, return 0. */
|
||
|
||
static int
|
||
addr_affects_sp_p (rtx addr)
|
||
{
|
||
if (GET_RTX_CLASS (GET_CODE (addr)) == RTX_AUTOINC
|
||
&& REG_P (XEXP (addr, 0))
|
||
&& REGNO (XEXP (addr, 0)) == STACK_POINTER_REGNUM)
|
||
{
|
||
if (REG_TICK (STACK_POINTER_REGNUM) >= 0)
|
||
{
|
||
REG_TICK (STACK_POINTER_REGNUM)++;
|
||
/* Is it possible to use a subreg of SP? */
|
||
SUBREG_TICKED (STACK_POINTER_REGNUM) = -1;
|
||
}
|
||
|
||
/* This should be *very* rare. */
|
||
if (TEST_HARD_REG_BIT (hard_regs_in_table, STACK_POINTER_REGNUM))
|
||
invalidate (stack_pointer_rtx, VOIDmode);
|
||
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Perform invalidation on the basis of everything about an insn
|
||
except for invalidating the actual places that are SET in it.
|
||
This includes the places CLOBBERed, and anything that might
|
||
alias with something that is SET or CLOBBERed.
|
||
|
||
X is the pattern of the insn. */
|
||
|
||
static void
|
||
invalidate_from_clobbers (rtx x)
|
||
{
|
||
if (GET_CODE (x) == CLOBBER)
|
||
{
|
||
rtx ref = XEXP (x, 0);
|
||
if (ref)
|
||
{
|
||
if (REG_P (ref) || GET_CODE (ref) == SUBREG
|
||
|| MEM_P (ref))
|
||
invalidate (ref, VOIDmode);
|
||
else if (GET_CODE (ref) == STRICT_LOW_PART
|
||
|| GET_CODE (ref) == ZERO_EXTRACT)
|
||
invalidate (XEXP (ref, 0), GET_MODE (ref));
|
||
}
|
||
}
|
||
else if (GET_CODE (x) == PARALLEL)
|
||
{
|
||
int i;
|
||
for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
|
||
{
|
||
rtx y = XVECEXP (x, 0, i);
|
||
if (GET_CODE (y) == CLOBBER)
|
||
{
|
||
rtx ref = XEXP (y, 0);
|
||
if (REG_P (ref) || GET_CODE (ref) == SUBREG
|
||
|| MEM_P (ref))
|
||
invalidate (ref, VOIDmode);
|
||
else if (GET_CODE (ref) == STRICT_LOW_PART
|
||
|| GET_CODE (ref) == ZERO_EXTRACT)
|
||
invalidate (XEXP (ref, 0), GET_MODE (ref));
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Process X, part of the REG_NOTES of an insn. Look at any REG_EQUAL notes
|
||
and replace any registers in them with either an equivalent constant
|
||
or the canonical form of the register. If we are inside an address,
|
||
only do this if the address remains valid.
|
||
|
||
OBJECT is 0 except when within a MEM in which case it is the MEM.
|
||
|
||
Return the replacement for X. */
|
||
|
||
static rtx
|
||
cse_process_notes (rtx x, rtx object)
|
||
{
|
||
enum rtx_code code = GET_CODE (x);
|
||
const char *fmt = GET_RTX_FORMAT (code);
|
||
int i;
|
||
|
||
switch (code)
|
||
{
|
||
case CONST_INT:
|
||
case CONST:
|
||
case SYMBOL_REF:
|
||
case LABEL_REF:
|
||
case CONST_DOUBLE:
|
||
case CONST_VECTOR:
|
||
case PC:
|
||
case CC0:
|
||
case LO_SUM:
|
||
return x;
|
||
|
||
case MEM:
|
||
validate_change (x, &XEXP (x, 0),
|
||
cse_process_notes (XEXP (x, 0), x), 0);
|
||
return x;
|
||
|
||
case EXPR_LIST:
|
||
case INSN_LIST:
|
||
if (REG_NOTE_KIND (x) == REG_EQUAL)
|
||
XEXP (x, 0) = cse_process_notes (XEXP (x, 0), NULL_RTX);
|
||
if (XEXP (x, 1))
|
||
XEXP (x, 1) = cse_process_notes (XEXP (x, 1), NULL_RTX);
|
||
return x;
|
||
|
||
case SIGN_EXTEND:
|
||
case ZERO_EXTEND:
|
||
case SUBREG:
|
||
{
|
||
rtx new = cse_process_notes (XEXP (x, 0), object);
|
||
/* We don't substitute VOIDmode constants into these rtx,
|
||
since they would impede folding. */
|
||
if (GET_MODE (new) != VOIDmode)
|
||
validate_change (object, &XEXP (x, 0), new, 0);
|
||
return x;
|
||
}
|
||
|
||
case REG:
|
||
i = REG_QTY (REGNO (x));
|
||
|
||
/* Return a constant or a constant register. */
|
||
if (REGNO_QTY_VALID_P (REGNO (x)))
|
||
{
|
||
struct qty_table_elem *ent = &qty_table[i];
|
||
|
||
if (ent->const_rtx != NULL_RTX
|
||
&& (CONSTANT_P (ent->const_rtx)
|
||
|| REG_P (ent->const_rtx)))
|
||
{
|
||
rtx new = gen_lowpart (GET_MODE (x), ent->const_rtx);
|
||
if (new)
|
||
return new;
|
||
}
|
||
}
|
||
|
||
/* Otherwise, canonicalize this register. */
|
||
return canon_reg (x, NULL_RTX);
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
for (i = 0; i < GET_RTX_LENGTH (code); i++)
|
||
if (fmt[i] == 'e')
|
||
validate_change (object, &XEXP (x, i),
|
||
cse_process_notes (XEXP (x, i), object), 0);
|
||
|
||
return x;
|
||
}
|
||
|
||
/* Process one SET of an insn that was skipped. We ignore CLOBBERs
|
||
since they are done elsewhere. This function is called via note_stores. */
|
||
|
||
static void
|
||
invalidate_skipped_set (rtx dest, rtx set, void *data ATTRIBUTE_UNUSED)
|
||
{
|
||
enum rtx_code code = GET_CODE (dest);
|
||
|
||
if (code == MEM
|
||
&& ! addr_affects_sp_p (dest) /* If this is not a stack push ... */
|
||
/* There are times when an address can appear varying and be a PLUS
|
||
during this scan when it would be a fixed address were we to know
|
||
the proper equivalences. So invalidate all memory if there is
|
||
a BLKmode or nonscalar memory reference or a reference to a
|
||
variable address. */
|
||
&& (MEM_IN_STRUCT_P (dest) || GET_MODE (dest) == BLKmode
|
||
|| cse_rtx_varies_p (XEXP (dest, 0), 0)))
|
||
{
|
||
invalidate_memory ();
|
||
return;
|
||
}
|
||
|
||
if (GET_CODE (set) == CLOBBER
|
||
|| CC0_P (dest)
|
||
|| dest == pc_rtx)
|
||
return;
|
||
|
||
if (code == STRICT_LOW_PART || code == ZERO_EXTRACT)
|
||
invalidate (XEXP (dest, 0), GET_MODE (dest));
|
||
else if (code == REG || code == SUBREG || code == MEM)
|
||
invalidate (dest, VOIDmode);
|
||
}
|
||
|
||
/* Invalidate all insns from START up to the end of the function or the
|
||
next label. This called when we wish to CSE around a block that is
|
||
conditionally executed. */
|
||
|
||
static void
|
||
invalidate_skipped_block (rtx start)
|
||
{
|
||
rtx insn;
|
||
|
||
for (insn = start; insn && !LABEL_P (insn);
|
||
insn = NEXT_INSN (insn))
|
||
{
|
||
if (! INSN_P (insn))
|
||
continue;
|
||
|
||
if (CALL_P (insn))
|
||
{
|
||
if (! CONST_OR_PURE_CALL_P (insn))
|
||
invalidate_memory ();
|
||
invalidate_for_call ();
|
||
}
|
||
|
||
invalidate_from_clobbers (PATTERN (insn));
|
||
note_stores (PATTERN (insn), invalidate_skipped_set, NULL);
|
||
}
|
||
}
|
||
|
||
/* Find the end of INSN's basic block and return its range,
|
||
the total number of SETs in all the insns of the block, the last insn of the
|
||
block, and the branch path.
|
||
|
||
The branch path indicates which branches should be followed. If a nonzero
|
||
path size is specified, the block should be rescanned and a different set
|
||
of branches will be taken. The branch path is only used if
|
||
FLAG_CSE_FOLLOW_JUMPS or FLAG_CSE_SKIP_BLOCKS is nonzero.
|
||
|
||
DATA is a pointer to a struct cse_basic_block_data, defined below, that is
|
||
used to describe the block. It is filled in with the information about
|
||
the current block. The incoming structure's branch path, if any, is used
|
||
to construct the output branch path. */
|
||
|
||
static void
|
||
cse_end_of_basic_block (rtx insn, struct cse_basic_block_data *data,
|
||
int follow_jumps, int skip_blocks)
|
||
{
|
||
rtx p = insn, q;
|
||
int nsets = 0;
|
||
int low_cuid = INSN_CUID (insn), high_cuid = INSN_CUID (insn);
|
||
rtx next = INSN_P (insn) ? insn : next_real_insn (insn);
|
||
int path_size = data->path_size;
|
||
int path_entry = 0;
|
||
int i;
|
||
|
||
/* Update the previous branch path, if any. If the last branch was
|
||
previously PATH_TAKEN, mark it PATH_NOT_TAKEN.
|
||
If it was previously PATH_NOT_TAKEN,
|
||
shorten the path by one and look at the previous branch. We know that
|
||
at least one branch must have been taken if PATH_SIZE is nonzero. */
|
||
while (path_size > 0)
|
||
{
|
||
if (data->path[path_size - 1].status != PATH_NOT_TAKEN)
|
||
{
|
||
data->path[path_size - 1].status = PATH_NOT_TAKEN;
|
||
break;
|
||
}
|
||
else
|
||
path_size--;
|
||
}
|
||
|
||
/* If the first instruction is marked with QImode, that means we've
|
||
already processed this block. Our caller will look at DATA->LAST
|
||
to figure out where to go next. We want to return the next block
|
||
in the instruction stream, not some branched-to block somewhere
|
||
else. We accomplish this by pretending our called forbid us to
|
||
follow jumps, or skip blocks. */
|
||
if (GET_MODE (insn) == QImode)
|
||
follow_jumps = skip_blocks = 0;
|
||
|
||
/* Scan to end of this basic block. */
|
||
while (p && !LABEL_P (p))
|
||
{
|
||
/* Don't cse over a call to setjmp; on some machines (eg VAX)
|
||
the regs restored by the longjmp come from
|
||
a later time than the setjmp. */
|
||
if (PREV_INSN (p) && CALL_P (PREV_INSN (p))
|
||
&& find_reg_note (PREV_INSN (p), REG_SETJMP, NULL))
|
||
break;
|
||
|
||
/* A PARALLEL can have lots of SETs in it,
|
||
especially if it is really an ASM_OPERANDS. */
|
||
if (INSN_P (p) && GET_CODE (PATTERN (p)) == PARALLEL)
|
||
nsets += XVECLEN (PATTERN (p), 0);
|
||
else if (!NOTE_P (p))
|
||
nsets += 1;
|
||
|
||
/* Ignore insns made by CSE; they cannot affect the boundaries of
|
||
the basic block. */
|
||
|
||
if (INSN_UID (p) <= max_uid && INSN_CUID (p) > high_cuid)
|
||
high_cuid = INSN_CUID (p);
|
||
if (INSN_UID (p) <= max_uid && INSN_CUID (p) < low_cuid)
|
||
low_cuid = INSN_CUID (p);
|
||
|
||
/* See if this insn is in our branch path. If it is and we are to
|
||
take it, do so. */
|
||
if (path_entry < path_size && data->path[path_entry].branch == p)
|
||
{
|
||
if (data->path[path_entry].status != PATH_NOT_TAKEN)
|
||
p = JUMP_LABEL (p);
|
||
|
||
/* Point to next entry in path, if any. */
|
||
path_entry++;
|
||
}
|
||
|
||
/* If this is a conditional jump, we can follow it if -fcse-follow-jumps
|
||
was specified, we haven't reached our maximum path length, there are
|
||
insns following the target of the jump, this is the only use of the
|
||
jump label, and the target label is preceded by a BARRIER.
|
||
|
||
Alternatively, we can follow the jump if it branches around a
|
||
block of code and there are no other branches into the block.
|
||
In this case invalidate_skipped_block will be called to invalidate any
|
||
registers set in the block when following the jump. */
|
||
|
||
else if ((follow_jumps || skip_blocks) && path_size < PARAM_VALUE (PARAM_MAX_CSE_PATH_LENGTH) - 1
|
||
&& JUMP_P (p)
|
||
&& GET_CODE (PATTERN (p)) == SET
|
||
&& GET_CODE (SET_SRC (PATTERN (p))) == IF_THEN_ELSE
|
||
&& JUMP_LABEL (p) != 0
|
||
&& LABEL_NUSES (JUMP_LABEL (p)) == 1
|
||
&& NEXT_INSN (JUMP_LABEL (p)) != 0)
|
||
{
|
||
for (q = PREV_INSN (JUMP_LABEL (p)); q; q = PREV_INSN (q))
|
||
if ((!NOTE_P (q)
|
||
|| (PREV_INSN (q) && CALL_P (PREV_INSN (q))
|
||
&& find_reg_note (PREV_INSN (q), REG_SETJMP, NULL)))
|
||
&& (!LABEL_P (q) || LABEL_NUSES (q) != 0))
|
||
break;
|
||
|
||
/* If we ran into a BARRIER, this code is an extension of the
|
||
basic block when the branch is taken. */
|
||
if (follow_jumps && q != 0 && BARRIER_P (q))
|
||
{
|
||
/* Don't allow ourself to keep walking around an
|
||
always-executed loop. */
|
||
if (next_real_insn (q) == next)
|
||
{
|
||
p = NEXT_INSN (p);
|
||
continue;
|
||
}
|
||
|
||
/* Similarly, don't put a branch in our path more than once. */
|
||
for (i = 0; i < path_entry; i++)
|
||
if (data->path[i].branch == p)
|
||
break;
|
||
|
||
if (i != path_entry)
|
||
break;
|
||
|
||
data->path[path_entry].branch = p;
|
||
data->path[path_entry++].status = PATH_TAKEN;
|
||
|
||
/* This branch now ends our path. It was possible that we
|
||
didn't see this branch the last time around (when the
|
||
insn in front of the target was a JUMP_INSN that was
|
||
turned into a no-op). */
|
||
path_size = path_entry;
|
||
|
||
p = JUMP_LABEL (p);
|
||
/* Mark block so we won't scan it again later. */
|
||
PUT_MODE (NEXT_INSN (p), QImode);
|
||
}
|
||
/* Detect a branch around a block of code. */
|
||
else if (skip_blocks && q != 0 && !LABEL_P (q))
|
||
{
|
||
rtx tmp;
|
||
|
||
if (next_real_insn (q) == next)
|
||
{
|
||
p = NEXT_INSN (p);
|
||
continue;
|
||
}
|
||
|
||
for (i = 0; i < path_entry; i++)
|
||
if (data->path[i].branch == p)
|
||
break;
|
||
|
||
if (i != path_entry)
|
||
break;
|
||
|
||
/* This is no_labels_between_p (p, q) with an added check for
|
||
reaching the end of a function (in case Q precedes P). */
|
||
for (tmp = NEXT_INSN (p); tmp && tmp != q; tmp = NEXT_INSN (tmp))
|
||
if (LABEL_P (tmp))
|
||
break;
|
||
|
||
if (tmp == q)
|
||
{
|
||
data->path[path_entry].branch = p;
|
||
data->path[path_entry++].status = PATH_AROUND;
|
||
|
||
path_size = path_entry;
|
||
|
||
p = JUMP_LABEL (p);
|
||
/* Mark block so we won't scan it again later. */
|
||
PUT_MODE (NEXT_INSN (p), QImode);
|
||
}
|
||
}
|
||
}
|
||
p = NEXT_INSN (p);
|
||
}
|
||
|
||
data->low_cuid = low_cuid;
|
||
data->high_cuid = high_cuid;
|
||
data->nsets = nsets;
|
||
data->last = p;
|
||
|
||
/* If all jumps in the path are not taken, set our path length to zero
|
||
so a rescan won't be done. */
|
||
for (i = path_size - 1; i >= 0; i--)
|
||
if (data->path[i].status != PATH_NOT_TAKEN)
|
||
break;
|
||
|
||
if (i == -1)
|
||
data->path_size = 0;
|
||
else
|
||
data->path_size = path_size;
|
||
|
||
/* End the current branch path. */
|
||
data->path[path_size].branch = 0;
|
||
}
|
||
|
||
/* Perform cse on the instructions of a function.
|
||
F is the first instruction.
|
||
NREGS is one plus the highest pseudo-reg number used in the instruction.
|
||
|
||
Returns 1 if jump_optimize should be redone due to simplifications
|
||
in conditional jump instructions. */
|
||
|
||
int
|
||
cse_main (rtx f, int nregs)
|
||
{
|
||
struct cse_basic_block_data val;
|
||
rtx insn = f;
|
||
int i;
|
||
|
||
init_cse_reg_info (nregs);
|
||
|
||
val.path = XNEWVEC (struct branch_path, PARAM_VALUE (PARAM_MAX_CSE_PATH_LENGTH));
|
||
|
||
cse_jumps_altered = 0;
|
||
recorded_label_ref = 0;
|
||
constant_pool_entries_cost = 0;
|
||
constant_pool_entries_regcost = 0;
|
||
val.path_size = 0;
|
||
rtl_hooks = cse_rtl_hooks;
|
||
|
||
init_recog ();
|
||
init_alias_analysis ();
|
||
|
||
reg_eqv_table = XNEWVEC (struct reg_eqv_elem, nregs);
|
||
|
||
/* Find the largest uid. */
|
||
|
||
max_uid = get_max_uid ();
|
||
uid_cuid = XCNEWVEC (int, max_uid + 1);
|
||
|
||
/* Compute the mapping from uids to cuids.
|
||
CUIDs are numbers assigned to insns, like uids,
|
||
except that cuids increase monotonically through the code.
|
||
Don't assign cuids to line-number NOTEs, so that the distance in cuids
|
||
between two insns is not affected by -g. */
|
||
|
||
for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
if (!NOTE_P (insn)
|
||
|| NOTE_LINE_NUMBER (insn) < 0)
|
||
INSN_CUID (insn) = ++i;
|
||
else
|
||
/* Give a line number note the same cuid as preceding insn. */
|
||
INSN_CUID (insn) = i;
|
||
}
|
||
|
||
/* Loop over basic blocks.
|
||
Compute the maximum number of qty's needed for each basic block
|
||
(which is 2 for each SET). */
|
||
insn = f;
|
||
while (insn)
|
||
{
|
||
cse_altered = 0;
|
||
cse_end_of_basic_block (insn, &val, flag_cse_follow_jumps,
|
||
flag_cse_skip_blocks);
|
||
|
||
/* If this basic block was already processed or has no sets, skip it. */
|
||
if (val.nsets == 0 || GET_MODE (insn) == QImode)
|
||
{
|
||
PUT_MODE (insn, VOIDmode);
|
||
insn = (val.last ? NEXT_INSN (val.last) : 0);
|
||
val.path_size = 0;
|
||
continue;
|
||
}
|
||
|
||
cse_basic_block_start = val.low_cuid;
|
||
cse_basic_block_end = val.high_cuid;
|
||
max_qty = val.nsets * 2;
|
||
|
||
if (dump_file)
|
||
fprintf (dump_file, ";; Processing block from %d to %d, %d sets.\n",
|
||
INSN_UID (insn), val.last ? INSN_UID (val.last) : 0,
|
||
val.nsets);
|
||
|
||
/* Make MAX_QTY bigger to give us room to optimize
|
||
past the end of this basic block, if that should prove useful. */
|
||
if (max_qty < 500)
|
||
max_qty = 500;
|
||
|
||
/* If this basic block is being extended by following certain jumps,
|
||
(see `cse_end_of_basic_block'), we reprocess the code from the start.
|
||
Otherwise, we start after this basic block. */
|
||
if (val.path_size > 0)
|
||
cse_basic_block (insn, val.last, val.path);
|
||
else
|
||
{
|
||
int old_cse_jumps_altered = cse_jumps_altered;
|
||
rtx temp;
|
||
|
||
/* When cse changes a conditional jump to an unconditional
|
||
jump, we want to reprocess the block, since it will give
|
||
us a new branch path to investigate. */
|
||
cse_jumps_altered = 0;
|
||
temp = cse_basic_block (insn, val.last, val.path);
|
||
if (cse_jumps_altered == 0
|
||
|| (flag_cse_follow_jumps == 0 && flag_cse_skip_blocks == 0))
|
||
insn = temp;
|
||
|
||
cse_jumps_altered |= old_cse_jumps_altered;
|
||
}
|
||
|
||
if (cse_altered)
|
||
ggc_collect ();
|
||
|
||
#ifdef USE_C_ALLOCA
|
||
alloca (0);
|
||
#endif
|
||
}
|
||
|
||
/* Clean up. */
|
||
end_alias_analysis ();
|
||
free (uid_cuid);
|
||
free (reg_eqv_table);
|
||
free (val.path);
|
||
rtl_hooks = general_rtl_hooks;
|
||
|
||
return cse_jumps_altered || recorded_label_ref;
|
||
}
|
||
|
||
/* Process a single basic block. FROM and TO and the limits of the basic
|
||
block. NEXT_BRANCH points to the branch path when following jumps or
|
||
a null path when not following jumps. */
|
||
|
||
static rtx
|
||
cse_basic_block (rtx from, rtx to, struct branch_path *next_branch)
|
||
{
|
||
rtx insn;
|
||
int to_usage = 0;
|
||
rtx libcall_insn = NULL_RTX;
|
||
int num_insns = 0;
|
||
int no_conflict = 0;
|
||
|
||
/* Allocate the space needed by qty_table. */
|
||
qty_table = XNEWVEC (struct qty_table_elem, max_qty);
|
||
|
||
new_basic_block ();
|
||
|
||
/* TO might be a label. If so, protect it from being deleted. */
|
||
if (to != 0 && LABEL_P (to))
|
||
++LABEL_NUSES (to);
|
||
|
||
for (insn = from; insn != to; insn = NEXT_INSN (insn))
|
||
{
|
||
enum rtx_code code = GET_CODE (insn);
|
||
|
||
/* If we have processed 1,000 insns, flush the hash table to
|
||
avoid extreme quadratic behavior. We must not include NOTEs
|
||
in the count since there may be more of them when generating
|
||
debugging information. If we clear the table at different
|
||
times, code generated with -g -O might be different than code
|
||
generated with -O but not -g.
|
||
|
||
??? This is a real kludge and needs to be done some other way.
|
||
Perhaps for 2.9. */
|
||
if (code != NOTE && num_insns++ > PARAM_VALUE (PARAM_MAX_CSE_INSNS))
|
||
{
|
||
flush_hash_table ();
|
||
num_insns = 0;
|
||
}
|
||
|
||
/* See if this is a branch that is part of the path. If so, and it is
|
||
to be taken, do so. */
|
||
if (next_branch->branch == insn)
|
||
{
|
||
enum taken status = next_branch++->status;
|
||
if (status != PATH_NOT_TAKEN)
|
||
{
|
||
if (status == PATH_TAKEN)
|
||
record_jump_equiv (insn, 1);
|
||
else
|
||
invalidate_skipped_block (NEXT_INSN (insn));
|
||
|
||
/* Set the last insn as the jump insn; it doesn't affect cc0.
|
||
Then follow this branch. */
|
||
#ifdef HAVE_cc0
|
||
prev_insn_cc0 = 0;
|
||
prev_insn = insn;
|
||
#endif
|
||
insn = JUMP_LABEL (insn);
|
||
continue;
|
||
}
|
||
}
|
||
|
||
if (GET_MODE (insn) == QImode)
|
||
PUT_MODE (insn, VOIDmode);
|
||
|
||
if (GET_RTX_CLASS (code) == RTX_INSN)
|
||
{
|
||
rtx p;
|
||
|
||
/* Process notes first so we have all notes in canonical forms when
|
||
looking for duplicate operations. */
|
||
|
||
if (REG_NOTES (insn))
|
||
REG_NOTES (insn) = cse_process_notes (REG_NOTES (insn), NULL_RTX);
|
||
|
||
/* Track when we are inside in LIBCALL block. Inside such a block,
|
||
we do not want to record destinations. The last insn of a
|
||
LIBCALL block is not considered to be part of the block, since
|
||
its destination is the result of the block and hence should be
|
||
recorded. */
|
||
|
||
if (REG_NOTES (insn) != 0)
|
||
{
|
||
if ((p = find_reg_note (insn, REG_LIBCALL, NULL_RTX)))
|
||
libcall_insn = XEXP (p, 0);
|
||
else if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
|
||
{
|
||
/* Keep libcall_insn for the last SET insn of a no-conflict
|
||
block to prevent changing the destination. */
|
||
if (! no_conflict)
|
||
libcall_insn = 0;
|
||
else
|
||
no_conflict = -1;
|
||
}
|
||
else if (find_reg_note (insn, REG_NO_CONFLICT, NULL_RTX))
|
||
no_conflict = 1;
|
||
}
|
||
|
||
cse_insn (insn, libcall_insn);
|
||
|
||
if (no_conflict == -1)
|
||
{
|
||
libcall_insn = 0;
|
||
no_conflict = 0;
|
||
}
|
||
|
||
/* If we haven't already found an insn where we added a LABEL_REF,
|
||
check this one. */
|
||
if (NONJUMP_INSN_P (insn) && ! recorded_label_ref
|
||
&& for_each_rtx (&PATTERN (insn), check_for_label_ref,
|
||
(void *) insn))
|
||
recorded_label_ref = 1;
|
||
}
|
||
|
||
/* If INSN is now an unconditional jump, skip to the end of our
|
||
basic block by pretending that we just did the last insn in the
|
||
basic block. If we are jumping to the end of our block, show
|
||
that we can have one usage of TO. */
|
||
|
||
if (any_uncondjump_p (insn))
|
||
{
|
||
if (to == 0)
|
||
{
|
||
free (qty_table);
|
||
return 0;
|
||
}
|
||
|
||
if (JUMP_LABEL (insn) == to)
|
||
to_usage = 1;
|
||
|
||
/* Maybe TO was deleted because the jump is unconditional.
|
||
If so, there is nothing left in this basic block. */
|
||
/* ??? Perhaps it would be smarter to set TO
|
||
to whatever follows this insn,
|
||
and pretend the basic block had always ended here. */
|
||
if (INSN_DELETED_P (to))
|
||
break;
|
||
|
||
insn = PREV_INSN (to);
|
||
}
|
||
|
||
/* See if it is ok to keep on going past the label
|
||
which used to end our basic block. Remember that we incremented
|
||
the count of that label, so we decrement it here. If we made
|
||
a jump unconditional, TO_USAGE will be one; in that case, we don't
|
||
want to count the use in that jump. */
|
||
|
||
if (to != 0 && NEXT_INSN (insn) == to
|
||
&& LABEL_P (to) && --LABEL_NUSES (to) == to_usage)
|
||
{
|
||
struct cse_basic_block_data val;
|
||
rtx prev;
|
||
|
||
insn = NEXT_INSN (to);
|
||
|
||
/* If TO was the last insn in the function, we are done. */
|
||
if (insn == 0)
|
||
{
|
||
free (qty_table);
|
||
return 0;
|
||
}
|
||
|
||
/* If TO was preceded by a BARRIER we are done with this block
|
||
because it has no continuation. */
|
||
prev = prev_nonnote_insn (to);
|
||
if (prev && BARRIER_P (prev))
|
||
{
|
||
free (qty_table);
|
||
return insn;
|
||
}
|
||
|
||
/* Find the end of the following block. Note that we won't be
|
||
following branches in this case. */
|
||
to_usage = 0;
|
||
val.path_size = 0;
|
||
val.path = XNEWVEC (struct branch_path, PARAM_VALUE (PARAM_MAX_CSE_PATH_LENGTH));
|
||
cse_end_of_basic_block (insn, &val, 0, 0);
|
||
free (val.path);
|
||
|
||
/* If the tables we allocated have enough space left
|
||
to handle all the SETs in the next basic block,
|
||
continue through it. Otherwise, return,
|
||
and that block will be scanned individually. */
|
||
if (val.nsets * 2 + next_qty > max_qty)
|
||
break;
|
||
|
||
cse_basic_block_start = val.low_cuid;
|
||
cse_basic_block_end = val.high_cuid;
|
||
to = val.last;
|
||
|
||
/* Prevent TO from being deleted if it is a label. */
|
||
if (to != 0 && LABEL_P (to))
|
||
++LABEL_NUSES (to);
|
||
|
||
/* Back up so we process the first insn in the extension. */
|
||
insn = PREV_INSN (insn);
|
||
}
|
||
}
|
||
|
||
gcc_assert (next_qty <= max_qty);
|
||
|
||
free (qty_table);
|
||
|
||
return to ? NEXT_INSN (to) : 0;
|
||
}
|
||
|
||
/* Called via for_each_rtx to see if an insn is using a LABEL_REF for which
|
||
there isn't a REG_LABEL note. Return one if so. DATA is the insn. */
|
||
|
||
static int
|
||
check_for_label_ref (rtx *rtl, void *data)
|
||
{
|
||
rtx insn = (rtx) data;
|
||
|
||
/* If this insn uses a LABEL_REF and there isn't a REG_LABEL note for it,
|
||
we must rerun jump since it needs to place the note. If this is a
|
||
LABEL_REF for a CODE_LABEL that isn't in the insn chain, don't do this
|
||
since no REG_LABEL will be added. */
|
||
return (GET_CODE (*rtl) == LABEL_REF
|
||
&& ! LABEL_REF_NONLOCAL_P (*rtl)
|
||
&& LABEL_P (XEXP (*rtl, 0))
|
||
&& INSN_UID (XEXP (*rtl, 0)) != 0
|
||
&& ! find_reg_note (insn, REG_LABEL, XEXP (*rtl, 0)));
|
||
}
|
||
|
||
/* Count the number of times registers are used (not set) in X.
|
||
COUNTS is an array in which we accumulate the count, INCR is how much
|
||
we count each register usage.
|
||
|
||
Don't count a usage of DEST, which is the SET_DEST of a SET which
|
||
contains X in its SET_SRC. This is because such a SET does not
|
||
modify the liveness of DEST.
|
||
DEST is set to pc_rtx for a trapping insn, which means that we must count
|
||
uses of a SET_DEST regardless because the insn can't be deleted here. */
|
||
|
||
static void
|
||
count_reg_usage (rtx x, int *counts, rtx dest, int incr)
|
||
{
|
||
enum rtx_code code;
|
||
rtx note;
|
||
const char *fmt;
|
||
int i, j;
|
||
|
||
if (x == 0)
|
||
return;
|
||
|
||
switch (code = GET_CODE (x))
|
||
{
|
||
case REG:
|
||
if (x != dest)
|
||
counts[REGNO (x)] += incr;
|
||
return;
|
||
|
||
case PC:
|
||
case CC0:
|
||
case CONST:
|
||
case CONST_INT:
|
||
case CONST_DOUBLE:
|
||
case CONST_VECTOR:
|
||
case SYMBOL_REF:
|
||
case LABEL_REF:
|
||
return;
|
||
|
||
case CLOBBER:
|
||
/* If we are clobbering a MEM, mark any registers inside the address
|
||
as being used. */
|
||
if (MEM_P (XEXP (x, 0)))
|
||
count_reg_usage (XEXP (XEXP (x, 0), 0), counts, NULL_RTX, incr);
|
||
return;
|
||
|
||
case SET:
|
||
/* Unless we are setting a REG, count everything in SET_DEST. */
|
||
if (!REG_P (SET_DEST (x)))
|
||
count_reg_usage (SET_DEST (x), counts, NULL_RTX, incr);
|
||
count_reg_usage (SET_SRC (x), counts,
|
||
dest ? dest : SET_DEST (x),
|
||
incr);
|
||
return;
|
||
|
||
case CALL_INSN:
|
||
case INSN:
|
||
case JUMP_INSN:
|
||
/* We expect dest to be NULL_RTX here. If the insn may trap, mark
|
||
this fact by setting DEST to pc_rtx. */
|
||
if (flag_non_call_exceptions && may_trap_p (PATTERN (x)))
|
||
dest = pc_rtx;
|
||
if (code == CALL_INSN)
|
||
count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, dest, incr);
|
||
count_reg_usage (PATTERN (x), counts, dest, incr);
|
||
|
||
/* Things used in a REG_EQUAL note aren't dead since loop may try to
|
||
use them. */
|
||
|
||
note = find_reg_equal_equiv_note (x);
|
||
if (note)
|
||
{
|
||
rtx eqv = XEXP (note, 0);
|
||
|
||
if (GET_CODE (eqv) == EXPR_LIST)
|
||
/* This REG_EQUAL note describes the result of a function call.
|
||
Process all the arguments. */
|
||
do
|
||
{
|
||
count_reg_usage (XEXP (eqv, 0), counts, dest, incr);
|
||
eqv = XEXP (eqv, 1);
|
||
}
|
||
while (eqv && GET_CODE (eqv) == EXPR_LIST);
|
||
else
|
||
count_reg_usage (eqv, counts, dest, incr);
|
||
}
|
||
return;
|
||
|
||
case EXPR_LIST:
|
||
if (REG_NOTE_KIND (x) == REG_EQUAL
|
||
|| (REG_NOTE_KIND (x) != REG_NONNEG && GET_CODE (XEXP (x,0)) == USE)
|
||
/* FUNCTION_USAGE expression lists may include (CLOBBER (mem /u)),
|
||
involving registers in the address. */
|
||
|| GET_CODE (XEXP (x, 0)) == CLOBBER)
|
||
count_reg_usage (XEXP (x, 0), counts, NULL_RTX, incr);
|
||
|
||
count_reg_usage (XEXP (x, 1), counts, NULL_RTX, incr);
|
||
return;
|
||
|
||
case ASM_OPERANDS:
|
||
/* If the asm is volatile, then this insn cannot be deleted,
|
||
and so the inputs *must* be live. */
|
||
if (MEM_VOLATILE_P (x))
|
||
dest = NULL_RTX;
|
||
/* Iterate over just the inputs, not the constraints as well. */
|
||
for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--)
|
||
count_reg_usage (ASM_OPERANDS_INPUT (x, i), counts, dest, incr);
|
||
return;
|
||
|
||
case INSN_LIST:
|
||
gcc_unreachable ();
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
count_reg_usage (XEXP (x, i), counts, dest, incr);
|
||
else if (fmt[i] == 'E')
|
||
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
|
||
count_reg_usage (XVECEXP (x, i, j), counts, dest, incr);
|
||
}
|
||
}
|
||
|
||
/* Return true if set is live. */
|
||
static bool
|
||
set_live_p (rtx set, rtx insn ATTRIBUTE_UNUSED, /* Only used with HAVE_cc0. */
|
||
int *counts)
|
||
{
|
||
#ifdef HAVE_cc0
|
||
rtx tem;
|
||
#endif
|
||
|
||
if (set_noop_p (set))
|
||
;
|
||
|
||
#ifdef HAVE_cc0
|
||
else if (GET_CODE (SET_DEST (set)) == CC0
|
||
&& !side_effects_p (SET_SRC (set))
|
||
&& ((tem = next_nonnote_insn (insn)) == 0
|
||
|| !INSN_P (tem)
|
||
|| !reg_referenced_p (cc0_rtx, PATTERN (tem))))
|
||
return false;
|
||
#endif
|
||
else if (!REG_P (SET_DEST (set))
|
||
|| REGNO (SET_DEST (set)) < FIRST_PSEUDO_REGISTER
|
||
|| counts[REGNO (SET_DEST (set))] != 0
|
||
|| side_effects_p (SET_SRC (set)))
|
||
return true;
|
||
return false;
|
||
}
|
||
|
||
/* Return true if insn is live. */
|
||
|
||
static bool
|
||
insn_live_p (rtx insn, int *counts)
|
||
{
|
||
int i;
|
||
if (flag_non_call_exceptions && may_trap_p (PATTERN (insn)))
|
||
return true;
|
||
else if (GET_CODE (PATTERN (insn)) == SET)
|
||
return set_live_p (PATTERN (insn), insn, counts);
|
||
else if (GET_CODE (PATTERN (insn)) == PARALLEL)
|
||
{
|
||
for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
|
||
{
|
||
rtx elt = XVECEXP (PATTERN (insn), 0, i);
|
||
|
||
if (GET_CODE (elt) == SET)
|
||
{
|
||
if (set_live_p (elt, insn, counts))
|
||
return true;
|
||
}
|
||
else if (GET_CODE (elt) != CLOBBER && GET_CODE (elt) != USE)
|
||
return true;
|
||
}
|
||
return false;
|
||
}
|
||
else
|
||
return true;
|
||
}
|
||
|
||
/* Return true if libcall is dead as a whole. */
|
||
|
||
static bool
|
||
dead_libcall_p (rtx insn, int *counts)
|
||
{
|
||
rtx note, set, new;
|
||
|
||
/* See if there's a REG_EQUAL note on this insn and try to
|
||
replace the source with the REG_EQUAL expression.
|
||
|
||
We assume that insns with REG_RETVALs can only be reg->reg
|
||
copies at this point. */
|
||
note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
|
||
if (!note)
|
||
return false;
|
||
|
||
set = single_set (insn);
|
||
if (!set)
|
||
return false;
|
||
|
||
new = simplify_rtx (XEXP (note, 0));
|
||
if (!new)
|
||
new = XEXP (note, 0);
|
||
|
||
/* While changing insn, we must update the counts accordingly. */
|
||
count_reg_usage (insn, counts, NULL_RTX, -1);
|
||
|
||
if (validate_change (insn, &SET_SRC (set), new, 0))
|
||
{
|
||
count_reg_usage (insn, counts, NULL_RTX, 1);
|
||
remove_note (insn, find_reg_note (insn, REG_RETVAL, NULL_RTX));
|
||
remove_note (insn, note);
|
||
return true;
|
||
}
|
||
|
||
if (CONSTANT_P (new))
|
||
{
|
||
new = force_const_mem (GET_MODE (SET_DEST (set)), new);
|
||
if (new && validate_change (insn, &SET_SRC (set), new, 0))
|
||
{
|
||
count_reg_usage (insn, counts, NULL_RTX, 1);
|
||
remove_note (insn, find_reg_note (insn, REG_RETVAL, NULL_RTX));
|
||
remove_note (insn, note);
|
||
return true;
|
||
}
|
||
}
|
||
|
||
count_reg_usage (insn, counts, NULL_RTX, 1);
|
||
return false;
|
||
}
|
||
|
||
/* Scan all the insns and delete any that are dead; i.e., they store a register
|
||
that is never used or they copy a register to itself.
|
||
|
||
This is used to remove insns made obviously dead by cse, loop or other
|
||
optimizations. It improves the heuristics in loop since it won't try to
|
||
move dead invariants out of loops or make givs for dead quantities. The
|
||
remaining passes of the compilation are also sped up. */
|
||
|
||
int
|
||
delete_trivially_dead_insns (rtx insns, int nreg)
|
||
{
|
||
int *counts;
|
||
rtx insn, prev;
|
||
int in_libcall = 0, dead_libcall = 0;
|
||
int ndead = 0;
|
||
|
||
timevar_push (TV_DELETE_TRIVIALLY_DEAD);
|
||
/* First count the number of times each register is used. */
|
||
counts = XCNEWVEC (int, nreg);
|
||
for (insn = insns; insn; insn = NEXT_INSN (insn))
|
||
if (INSN_P (insn))
|
||
count_reg_usage (insn, counts, NULL_RTX, 1);
|
||
|
||
/* Go from the last insn to the first and delete insns that only set unused
|
||
registers or copy a register to itself. As we delete an insn, remove
|
||
usage counts for registers it uses.
|
||
|
||
The first jump optimization pass may leave a real insn as the last
|
||
insn in the function. We must not skip that insn or we may end
|
||
up deleting code that is not really dead. */
|
||
for (insn = get_last_insn (); insn; insn = prev)
|
||
{
|
||
int live_insn = 0;
|
||
|
||
prev = PREV_INSN (insn);
|
||
if (!INSN_P (insn))
|
||
continue;
|
||
|
||
/* Don't delete any insns that are part of a libcall block unless
|
||
we can delete the whole libcall block.
|
||
|
||
Flow or loop might get confused if we did that. Remember
|
||
that we are scanning backwards. */
|
||
if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
|
||
{
|
||
in_libcall = 1;
|
||
live_insn = 1;
|
||
dead_libcall = dead_libcall_p (insn, counts);
|
||
}
|
||
else if (in_libcall)
|
||
live_insn = ! dead_libcall;
|
||
else
|
||
live_insn = insn_live_p (insn, counts);
|
||
|
||
/* If this is a dead insn, delete it and show registers in it aren't
|
||
being used. */
|
||
|
||
if (! live_insn)
|
||
{
|
||
count_reg_usage (insn, counts, NULL_RTX, -1);
|
||
delete_insn_and_edges (insn);
|
||
ndead++;
|
||
}
|
||
|
||
if (in_libcall && find_reg_note (insn, REG_LIBCALL, NULL_RTX))
|
||
{
|
||
in_libcall = 0;
|
||
dead_libcall = 0;
|
||
}
|
||
}
|
||
|
||
if (dump_file && ndead)
|
||
fprintf (dump_file, "Deleted %i trivially dead insns\n",
|
||
ndead);
|
||
/* Clean up. */
|
||
free (counts);
|
||
timevar_pop (TV_DELETE_TRIVIALLY_DEAD);
|
||
return ndead;
|
||
}
|
||
|
||
/* This function is called via for_each_rtx. The argument, NEWREG, is
|
||
a condition code register with the desired mode. If we are looking
|
||
at the same register in a different mode, replace it with
|
||
NEWREG. */
|
||
|
||
static int
|
||
cse_change_cc_mode (rtx *loc, void *data)
|
||
{
|
||
struct change_cc_mode_args* args = (struct change_cc_mode_args*)data;
|
||
|
||
if (*loc
|
||
&& REG_P (*loc)
|
||
&& REGNO (*loc) == REGNO (args->newreg)
|
||
&& GET_MODE (*loc) != GET_MODE (args->newreg))
|
||
{
|
||
validate_change (args->insn, loc, args->newreg, 1);
|
||
|
||
return -1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Change the mode of any reference to the register REGNO (NEWREG) to
|
||
GET_MODE (NEWREG) in INSN. */
|
||
|
||
static void
|
||
cse_change_cc_mode_insn (rtx insn, rtx newreg)
|
||
{
|
||
struct change_cc_mode_args args;
|
||
int success;
|
||
|
||
if (!INSN_P (insn))
|
||
return;
|
||
|
||
args.insn = insn;
|
||
args.newreg = newreg;
|
||
|
||
for_each_rtx (&PATTERN (insn), cse_change_cc_mode, &args);
|
||
for_each_rtx (®_NOTES (insn), cse_change_cc_mode, &args);
|
||
|
||
/* If the following assertion was triggered, there is most probably
|
||
something wrong with the cc_modes_compatible back end function.
|
||
CC modes only can be considered compatible if the insn - with the mode
|
||
replaced by any of the compatible modes - can still be recognized. */
|
||
success = apply_change_group ();
|
||
gcc_assert (success);
|
||
}
|
||
|
||
/* Change the mode of any reference to the register REGNO (NEWREG) to
|
||
GET_MODE (NEWREG), starting at START. Stop before END. Stop at
|
||
any instruction which modifies NEWREG. */
|
||
|
||
static void
|
||
cse_change_cc_mode_insns (rtx start, rtx end, rtx newreg)
|
||
{
|
||
rtx insn;
|
||
|
||
for (insn = start; insn != end; insn = NEXT_INSN (insn))
|
||
{
|
||
if (! INSN_P (insn))
|
||
continue;
|
||
|
||
if (reg_set_p (newreg, insn))
|
||
return;
|
||
|
||
cse_change_cc_mode_insn (insn, newreg);
|
||
}
|
||
}
|
||
|
||
/* BB is a basic block which finishes with CC_REG as a condition code
|
||
register which is set to CC_SRC. Look through the successors of BB
|
||
to find blocks which have a single predecessor (i.e., this one),
|
||
and look through those blocks for an assignment to CC_REG which is
|
||
equivalent to CC_SRC. CAN_CHANGE_MODE indicates whether we are
|
||
permitted to change the mode of CC_SRC to a compatible mode. This
|
||
returns VOIDmode if no equivalent assignments were found.
|
||
Otherwise it returns the mode which CC_SRC should wind up with.
|
||
|
||
The main complexity in this function is handling the mode issues.
|
||
We may have more than one duplicate which we can eliminate, and we
|
||
try to find a mode which will work for multiple duplicates. */
|
||
|
||
static enum machine_mode
|
||
cse_cc_succs (basic_block bb, rtx cc_reg, rtx cc_src, bool can_change_mode)
|
||
{
|
||
bool found_equiv;
|
||
enum machine_mode mode;
|
||
unsigned int insn_count;
|
||
edge e;
|
||
rtx insns[2];
|
||
enum machine_mode modes[2];
|
||
rtx last_insns[2];
|
||
unsigned int i;
|
||
rtx newreg;
|
||
edge_iterator ei;
|
||
|
||
/* We expect to have two successors. Look at both before picking
|
||
the final mode for the comparison. If we have more successors
|
||
(i.e., some sort of table jump, although that seems unlikely),
|
||
then we require all beyond the first two to use the same
|
||
mode. */
|
||
|
||
found_equiv = false;
|
||
mode = GET_MODE (cc_src);
|
||
insn_count = 0;
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
{
|
||
rtx insn;
|
||
rtx end;
|
||
|
||
if (e->flags & EDGE_COMPLEX)
|
||
continue;
|
||
|
||
if (EDGE_COUNT (e->dest->preds) != 1
|
||
|| e->dest == EXIT_BLOCK_PTR)
|
||
continue;
|
||
|
||
end = NEXT_INSN (BB_END (e->dest));
|
||
for (insn = BB_HEAD (e->dest); insn != end; insn = NEXT_INSN (insn))
|
||
{
|
||
rtx set;
|
||
|
||
if (! INSN_P (insn))
|
||
continue;
|
||
|
||
/* If CC_SRC is modified, we have to stop looking for
|
||
something which uses it. */
|
||
if (modified_in_p (cc_src, insn))
|
||
break;
|
||
|
||
/* Check whether INSN sets CC_REG to CC_SRC. */
|
||
set = single_set (insn);
|
||
if (set
|
||
&& REG_P (SET_DEST (set))
|
||
&& REGNO (SET_DEST (set)) == REGNO (cc_reg))
|
||
{
|
||
bool found;
|
||
enum machine_mode set_mode;
|
||
enum machine_mode comp_mode;
|
||
|
||
found = false;
|
||
set_mode = GET_MODE (SET_SRC (set));
|
||
comp_mode = set_mode;
|
||
if (rtx_equal_p (cc_src, SET_SRC (set)))
|
||
found = true;
|
||
else if (GET_CODE (cc_src) == COMPARE
|
||
&& GET_CODE (SET_SRC (set)) == COMPARE
|
||
&& mode != set_mode
|
||
&& rtx_equal_p (XEXP (cc_src, 0),
|
||
XEXP (SET_SRC (set), 0))
|
||
&& rtx_equal_p (XEXP (cc_src, 1),
|
||
XEXP (SET_SRC (set), 1)))
|
||
|
||
{
|
||
comp_mode = targetm.cc_modes_compatible (mode, set_mode);
|
||
if (comp_mode != VOIDmode
|
||
&& (can_change_mode || comp_mode == mode))
|
||
found = true;
|
||
}
|
||
|
||
if (found)
|
||
{
|
||
found_equiv = true;
|
||
if (insn_count < ARRAY_SIZE (insns))
|
||
{
|
||
insns[insn_count] = insn;
|
||
modes[insn_count] = set_mode;
|
||
last_insns[insn_count] = end;
|
||
++insn_count;
|
||
|
||
if (mode != comp_mode)
|
||
{
|
||
gcc_assert (can_change_mode);
|
||
mode = comp_mode;
|
||
|
||
/* The modified insn will be re-recognized later. */
|
||
PUT_MODE (cc_src, mode);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (set_mode != mode)
|
||
{
|
||
/* We found a matching expression in the
|
||
wrong mode, but we don't have room to
|
||
store it in the array. Punt. This case
|
||
should be rare. */
|
||
break;
|
||
}
|
||
/* INSN sets CC_REG to a value equal to CC_SRC
|
||
with the right mode. We can simply delete
|
||
it. */
|
||
delete_insn (insn);
|
||
}
|
||
|
||
/* We found an instruction to delete. Keep looking,
|
||
in the hopes of finding a three-way jump. */
|
||
continue;
|
||
}
|
||
|
||
/* We found an instruction which sets the condition
|
||
code, so don't look any farther. */
|
||
break;
|
||
}
|
||
|
||
/* If INSN sets CC_REG in some other way, don't look any
|
||
farther. */
|
||
if (reg_set_p (cc_reg, insn))
|
||
break;
|
||
}
|
||
|
||
/* If we fell off the bottom of the block, we can keep looking
|
||
through successors. We pass CAN_CHANGE_MODE as false because
|
||
we aren't prepared to handle compatibility between the
|
||
further blocks and this block. */
|
||
if (insn == end)
|
||
{
|
||
enum machine_mode submode;
|
||
|
||
submode = cse_cc_succs (e->dest, cc_reg, cc_src, false);
|
||
if (submode != VOIDmode)
|
||
{
|
||
gcc_assert (submode == mode);
|
||
found_equiv = true;
|
||
can_change_mode = false;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (! found_equiv)
|
||
return VOIDmode;
|
||
|
||
/* Now INSN_COUNT is the number of instructions we found which set
|
||
CC_REG to a value equivalent to CC_SRC. The instructions are in
|
||
INSNS. The modes used by those instructions are in MODES. */
|
||
|
||
newreg = NULL_RTX;
|
||
for (i = 0; i < insn_count; ++i)
|
||
{
|
||
if (modes[i] != mode)
|
||
{
|
||
/* We need to change the mode of CC_REG in INSNS[i] and
|
||
subsequent instructions. */
|
||
if (! newreg)
|
||
{
|
||
if (GET_MODE (cc_reg) == mode)
|
||
newreg = cc_reg;
|
||
else
|
||
newreg = gen_rtx_REG (mode, REGNO (cc_reg));
|
||
}
|
||
cse_change_cc_mode_insns (NEXT_INSN (insns[i]), last_insns[i],
|
||
newreg);
|
||
}
|
||
|
||
delete_insn (insns[i]);
|
||
}
|
||
|
||
return mode;
|
||
}
|
||
|
||
/* If we have a fixed condition code register (or two), walk through
|
||
the instructions and try to eliminate duplicate assignments. */
|
||
|
||
static void
|
||
cse_condition_code_reg (void)
|
||
{
|
||
unsigned int cc_regno_1;
|
||
unsigned int cc_regno_2;
|
||
rtx cc_reg_1;
|
||
rtx cc_reg_2;
|
||
basic_block bb;
|
||
|
||
if (! targetm.fixed_condition_code_regs (&cc_regno_1, &cc_regno_2))
|
||
return;
|
||
|
||
cc_reg_1 = gen_rtx_REG (CCmode, cc_regno_1);
|
||
if (cc_regno_2 != INVALID_REGNUM)
|
||
cc_reg_2 = gen_rtx_REG (CCmode, cc_regno_2);
|
||
else
|
||
cc_reg_2 = NULL_RTX;
|
||
|
||
FOR_EACH_BB (bb)
|
||
{
|
||
rtx last_insn;
|
||
rtx cc_reg;
|
||
rtx insn;
|
||
rtx cc_src_insn;
|
||
rtx cc_src;
|
||
enum machine_mode mode;
|
||
enum machine_mode orig_mode;
|
||
|
||
/* Look for blocks which end with a conditional jump based on a
|
||
condition code register. Then look for the instruction which
|
||
sets the condition code register. Then look through the
|
||
successor blocks for instructions which set the condition
|
||
code register to the same value. There are other possible
|
||
uses of the condition code register, but these are by far the
|
||
most common and the ones which we are most likely to be able
|
||
to optimize. */
|
||
|
||
last_insn = BB_END (bb);
|
||
if (!JUMP_P (last_insn))
|
||
continue;
|
||
|
||
if (reg_referenced_p (cc_reg_1, PATTERN (last_insn)))
|
||
cc_reg = cc_reg_1;
|
||
else if (cc_reg_2 && reg_referenced_p (cc_reg_2, PATTERN (last_insn)))
|
||
cc_reg = cc_reg_2;
|
||
else
|
||
continue;
|
||
|
||
cc_src_insn = NULL_RTX;
|
||
cc_src = NULL_RTX;
|
||
for (insn = PREV_INSN (last_insn);
|
||
insn && insn != PREV_INSN (BB_HEAD (bb));
|
||
insn = PREV_INSN (insn))
|
||
{
|
||
rtx set;
|
||
|
||
if (! INSN_P (insn))
|
||
continue;
|
||
set = single_set (insn);
|
||
if (set
|
||
&& REG_P (SET_DEST (set))
|
||
&& REGNO (SET_DEST (set)) == REGNO (cc_reg))
|
||
{
|
||
cc_src_insn = insn;
|
||
cc_src = SET_SRC (set);
|
||
break;
|
||
}
|
||
else if (reg_set_p (cc_reg, insn))
|
||
break;
|
||
}
|
||
|
||
if (! cc_src_insn)
|
||
continue;
|
||
|
||
if (modified_between_p (cc_src, cc_src_insn, NEXT_INSN (last_insn)))
|
||
continue;
|
||
|
||
/* Now CC_REG is a condition code register used for a
|
||
conditional jump at the end of the block, and CC_SRC, in
|
||
CC_SRC_INSN, is the value to which that condition code
|
||
register is set, and CC_SRC is still meaningful at the end of
|
||
the basic block. */
|
||
|
||
orig_mode = GET_MODE (cc_src);
|
||
mode = cse_cc_succs (bb, cc_reg, cc_src, true);
|
||
if (mode != VOIDmode)
|
||
{
|
||
gcc_assert (mode == GET_MODE (cc_src));
|
||
if (mode != orig_mode)
|
||
{
|
||
rtx newreg = gen_rtx_REG (mode, REGNO (cc_reg));
|
||
|
||
cse_change_cc_mode_insn (cc_src_insn, newreg);
|
||
|
||
/* Do the same in the following insns that use the
|
||
current value of CC_REG within BB. */
|
||
cse_change_cc_mode_insns (NEXT_INSN (cc_src_insn),
|
||
NEXT_INSN (last_insn),
|
||
newreg);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
/* Perform common subexpression elimination. Nonzero value from
|
||
`cse_main' means that jumps were simplified and some code may now
|
||
be unreachable, so do jump optimization again. */
|
||
static bool
|
||
gate_handle_cse (void)
|
||
{
|
||
return optimize > 0;
|
||
}
|
||
|
||
static unsigned int
|
||
rest_of_handle_cse (void)
|
||
{
|
||
int tem;
|
||
|
||
if (dump_file)
|
||
dump_flow_info (dump_file, dump_flags);
|
||
|
||
reg_scan (get_insns (), max_reg_num ());
|
||
|
||
tem = cse_main (get_insns (), max_reg_num ());
|
||
if (tem)
|
||
rebuild_jump_labels (get_insns ());
|
||
if (purge_all_dead_edges ())
|
||
delete_unreachable_blocks ();
|
||
|
||
delete_trivially_dead_insns (get_insns (), max_reg_num ());
|
||
|
||
/* If we are not running more CSE passes, then we are no longer
|
||
expecting CSE to be run. But always rerun it in a cheap mode. */
|
||
cse_not_expected = !flag_rerun_cse_after_loop && !flag_gcse;
|
||
|
||
if (tem)
|
||
delete_dead_jumptables ();
|
||
|
||
if (tem || optimize > 1)
|
||
cleanup_cfg (CLEANUP_EXPENSIVE);
|
||
return 0;
|
||
}
|
||
|
||
struct tree_opt_pass pass_cse =
|
||
{
|
||
"cse1", /* name */
|
||
gate_handle_cse, /* gate */
|
||
rest_of_handle_cse, /* execute */
|
||
NULL, /* sub */
|
||
NULL, /* next */
|
||
0, /* static_pass_number */
|
||
TV_CSE, /* tv_id */
|
||
0, /* properties_required */
|
||
0, /* properties_provided */
|
||
0, /* properties_destroyed */
|
||
0, /* todo_flags_start */
|
||
TODO_dump_func |
|
||
TODO_ggc_collect, /* todo_flags_finish */
|
||
's' /* letter */
|
||
};
|
||
|
||
|
||
static bool
|
||
gate_handle_cse2 (void)
|
||
{
|
||
return optimize > 0 && flag_rerun_cse_after_loop;
|
||
}
|
||
|
||
/* Run second CSE pass after loop optimizations. */
|
||
static unsigned int
|
||
rest_of_handle_cse2 (void)
|
||
{
|
||
int tem;
|
||
|
||
if (dump_file)
|
||
dump_flow_info (dump_file, dump_flags);
|
||
|
||
tem = cse_main (get_insns (), max_reg_num ());
|
||
|
||
/* Run a pass to eliminate duplicated assignments to condition code
|
||
registers. We have to run this after bypass_jumps, because it
|
||
makes it harder for that pass to determine whether a jump can be
|
||
bypassed safely. */
|
||
cse_condition_code_reg ();
|
||
|
||
purge_all_dead_edges ();
|
||
delete_trivially_dead_insns (get_insns (), max_reg_num ());
|
||
|
||
if (tem)
|
||
{
|
||
timevar_push (TV_JUMP);
|
||
rebuild_jump_labels (get_insns ());
|
||
delete_dead_jumptables ();
|
||
cleanup_cfg (CLEANUP_EXPENSIVE);
|
||
timevar_pop (TV_JUMP);
|
||
}
|
||
reg_scan (get_insns (), max_reg_num ());
|
||
cse_not_expected = 1;
|
||
return 0;
|
||
}
|
||
|
||
|
||
struct tree_opt_pass pass_cse2 =
|
||
{
|
||
"cse2", /* name */
|
||
gate_handle_cse2, /* gate */
|
||
rest_of_handle_cse2, /* execute */
|
||
NULL, /* sub */
|
||
NULL, /* next */
|
||
0, /* static_pass_number */
|
||
TV_CSE2, /* tv_id */
|
||
0, /* properties_required */
|
||
0, /* properties_provided */
|
||
0, /* properties_destroyed */
|
||
0, /* todo_flags_start */
|
||
TODO_dump_func |
|
||
TODO_ggc_collect, /* todo_flags_finish */
|
||
't' /* letter */
|
||
};
|
||
|