771 lines
24 KiB
C
771 lines
24 KiB
C
/* Dummy data flow analysis for GNU compiler in nonoptimizing mode.
|
||
Copyright (C) 1987, 91, 94-96, 1998 Free Software Foundation, Inc.
|
||
|
||
This file is part of GNU CC.
|
||
|
||
GNU CC 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.
|
||
|
||
GNU CC 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 GNU CC; see the file COPYING. If not, write to
|
||
the Free Software Foundation, 59 Temple Place - Suite 330,
|
||
Boston, MA 02111-1307, USA. */
|
||
|
||
|
||
/* This file performs stupid register allocation, which is used
|
||
when cc1 gets the -noreg switch (which is when cc does not get -O).
|
||
|
||
Stupid register allocation goes in place of the flow_analysis,
|
||
local_alloc and global_alloc passes. combine_instructions cannot
|
||
be done with stupid allocation because the data flow info that it needs
|
||
is not computed here.
|
||
|
||
In stupid allocation, the only user-defined variables that can
|
||
go in registers are those declared "register". They are assumed
|
||
to have a life span equal to their scope. Other user variables
|
||
are given stack slots in the rtl-generation pass and are not
|
||
represented as pseudo regs. A compiler-generated temporary
|
||
is assumed to live from its first mention to its last mention.
|
||
|
||
Since each pseudo-reg's life span is just an interval, it can be
|
||
represented as a pair of numbers, each of which identifies an insn by
|
||
its position in the function (number of insns before it). The first
|
||
thing done for stupid allocation is to compute such a number for each
|
||
insn. It is called the suid. Then the life-interval of each
|
||
pseudo reg is computed. Then the pseudo regs are ordered by priority
|
||
and assigned hard regs in priority order. */
|
||
|
||
#include "config.h"
|
||
#include "system.h"
|
||
|
||
#include "rtl.h"
|
||
#include "hard-reg-set.h"
|
||
#include "basic-block.h"
|
||
#include "regs.h"
|
||
#include "insn-config.h"
|
||
#include "reload.h"
|
||
#include "flags.h"
|
||
#include "toplev.h"
|
||
|
||
/* Vector mapping INSN_UIDs to suids.
|
||
The suids are like uids but increase monotonically always.
|
||
We use them to see whether a subroutine call came
|
||
between a variable's birth and its death. */
|
||
|
||
static int *uid_suid;
|
||
|
||
/* Get the suid of an insn. */
|
||
|
||
#define INSN_SUID(INSN) (uid_suid[INSN_UID (INSN)])
|
||
|
||
/* Record the suid of the last CALL_INSN
|
||
so we can tell whether a pseudo reg crosses any calls. */
|
||
|
||
static int last_call_suid;
|
||
|
||
/* Record the suid of the last NOTE_INSN_SETJMP
|
||
so we can tell whether a pseudo reg crosses any setjmp. */
|
||
|
||
static int last_setjmp_suid;
|
||
|
||
/* Element N is suid of insn where life span of pseudo reg N ends.
|
||
Element is 0 if register N has not been seen yet on backward scan. */
|
||
|
||
static int *reg_where_dead;
|
||
|
||
/* Likewise, but point to the insn_chain structure of the insn at which
|
||
the reg dies. */
|
||
static struct insn_chain **reg_where_dead_chain;
|
||
|
||
/* Element N is suid of insn where life span of pseudo reg N begins. */
|
||
static int *reg_where_born_exact;
|
||
|
||
/* Element N is 1 if the birth of pseudo reg N is due to a CLOBBER,
|
||
0 otherwise. */
|
||
static int *reg_where_born_clobber;
|
||
|
||
/* Return the suid of the insn where the register is born, or the suid
|
||
of the insn before if the birth is due to a CLOBBER. */
|
||
#define REG_WHERE_BORN(N) \
|
||
(reg_where_born_exact[(N)] - reg_where_born_clobber[(N)])
|
||
|
||
/* Numbers of pseudo-regs to be allocated, highest priority first. */
|
||
|
||
static int *reg_order;
|
||
|
||
/* Indexed by reg number (hard or pseudo), nonzero if register is live
|
||
at the current point in the instruction stream. */
|
||
|
||
static char *regs_live;
|
||
|
||
/* Indexed by reg number, nonzero if reg was used in a SUBREG that changes
|
||
its size. */
|
||
|
||
static char *regs_change_size;
|
||
|
||
/* Indexed by reg number, nonzero if reg crosses a setjmp. */
|
||
|
||
static char *regs_crosses_setjmp;
|
||
|
||
/* Indexed by insn's suid, the set of hard regs live after that insn. */
|
||
|
||
static HARD_REG_SET *after_insn_hard_regs;
|
||
|
||
/* Record that hard reg REGNO is live after insn INSN. */
|
||
|
||
#define MARK_LIVE_AFTER(INSN,REGNO) \
|
||
SET_HARD_REG_BIT (after_insn_hard_regs[INSN_SUID (INSN)], (REGNO))
|
||
|
||
static int stupid_reg_compare PROTO((const GENERIC_PTR,const GENERIC_PTR));
|
||
static int stupid_find_reg PROTO((int, enum reg_class, enum machine_mode,
|
||
int, int, int));
|
||
static void stupid_mark_refs PROTO((rtx, struct insn_chain *));
|
||
static void find_clobbered_regs PROTO((rtx, rtx));
|
||
|
||
/* For communication between stupid_life_analysis and find_clobbered_regs. */
|
||
static struct insn_chain *current_chain;
|
||
|
||
/* This function, called via note_stores, marks any hard registers that are
|
||
clobbered in an insn as being live in the live_after and live_before fields
|
||
of the appropriate insn_chain structure. */
|
||
|
||
static void
|
||
find_clobbered_regs (reg, setter)
|
||
rtx reg, setter;
|
||
{
|
||
int regno, nregs;
|
||
if (setter == 0 || GET_CODE (setter) != CLOBBER)
|
||
return;
|
||
|
||
if (GET_CODE (reg) == SUBREG)
|
||
reg = SUBREG_REG (reg);
|
||
|
||
if (GET_CODE (reg) != REG)
|
||
return;
|
||
regno = REGNO (reg);
|
||
if (regno >= FIRST_PSEUDO_REGISTER)
|
||
return;
|
||
|
||
if (GET_MODE (reg) == VOIDmode)
|
||
abort ();
|
||
else
|
||
nregs = HARD_REGNO_NREGS (regno, GET_MODE (reg));
|
||
while (nregs-- > 0)
|
||
{
|
||
SET_REGNO_REG_SET (current_chain->live_after, regno);
|
||
SET_REGNO_REG_SET (current_chain->live_before, regno++);
|
||
}
|
||
}
|
||
|
||
/* Stupid life analysis is for the case where only variables declared
|
||
`register' go in registers. For this case, we mark all
|
||
pseudo-registers that belong to register variables as
|
||
dying in the last instruction of the function, and all other
|
||
pseudo registers as dying in the last place they are referenced.
|
||
Hard registers are marked as dying in the last reference before
|
||
the end or before each store into them. */
|
||
|
||
void
|
||
stupid_life_analysis (f, nregs, file)
|
||
rtx f;
|
||
int nregs;
|
||
FILE *file;
|
||
{
|
||
register int i;
|
||
register rtx last, insn;
|
||
int max_uid, max_suid;
|
||
|
||
current_function_has_computed_jump = 0;
|
||
|
||
bzero (regs_ever_live, sizeof regs_ever_live);
|
||
|
||
regs_live = (char *) xmalloc (nregs);
|
||
|
||
/* First find the last real insn, and count the number of insns,
|
||
and assign insns their suids. */
|
||
|
||
for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
|
||
if (INSN_UID (insn) > i)
|
||
i = INSN_UID (insn);
|
||
|
||
max_uid = i + 1;
|
||
uid_suid = (int *) xmalloc ((i + 1) * sizeof (int));
|
||
|
||
/* Compute the mapping from uids to suids.
|
||
Suids are numbers assigned to insns, like uids,
|
||
except that suids increase monotonically through the code. */
|
||
|
||
last = 0; /* In case of empty function body */
|
||
for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
|
||
last = insn;
|
||
|
||
INSN_SUID (insn) = ++i;
|
||
}
|
||
|
||
last_call_suid = i + 1;
|
||
last_setjmp_suid = i + 1;
|
||
max_suid = i + 1;
|
||
|
||
max_regno = nregs;
|
||
|
||
/* Allocate tables to record info about regs. */
|
||
|
||
reg_where_dead = (int *) xmalloc (nregs * sizeof (int));
|
||
bzero ((char *) reg_where_dead, nregs * sizeof (int));
|
||
|
||
reg_where_born_exact = (int *) xmalloc (nregs * sizeof (int));
|
||
bzero ((char *) reg_where_born_exact, nregs * sizeof (int));
|
||
|
||
reg_where_born_clobber = (int *) xmalloc (nregs * sizeof (int));
|
||
bzero ((char *) reg_where_born_clobber, nregs * sizeof (int));
|
||
|
||
reg_where_dead_chain = (struct insn_chain **) xmalloc (nregs * sizeof (struct insn_chain *));
|
||
bzero ((char *) reg_where_dead_chain, nregs * sizeof (struct insn_chain *));
|
||
|
||
reg_order = (int *) xmalloc (nregs * sizeof (int));
|
||
bzero ((char *) reg_order, nregs * sizeof (int));
|
||
|
||
regs_change_size = (char *) xmalloc (nregs * sizeof (char));
|
||
bzero ((char *) regs_change_size, nregs * sizeof (char));
|
||
|
||
regs_crosses_setjmp = (char *) xmalloc (nregs * sizeof (char));
|
||
bzero ((char *) regs_crosses_setjmp, nregs * sizeof (char));
|
||
|
||
/* Allocate the reg_renumber array */
|
||
allocate_reg_info (max_regno, FALSE, TRUE);
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
reg_renumber[i] = i;
|
||
|
||
after_insn_hard_regs
|
||
= (HARD_REG_SET *) xmalloc (max_suid * sizeof (HARD_REG_SET));
|
||
|
||
bzero ((char *) after_insn_hard_regs, max_suid * sizeof (HARD_REG_SET));
|
||
|
||
/* Allocate and zero out many data structures
|
||
that will record the data from lifetime analysis. */
|
||
|
||
allocate_reg_life_data ();
|
||
allocate_bb_life_data ();
|
||
|
||
for (i = 0; i < max_regno; i++)
|
||
REG_N_DEATHS (i) = 1;
|
||
|
||
bzero (regs_live, nregs);
|
||
|
||
/* Find where each pseudo register is born and dies,
|
||
by scanning all insns from the end to the start
|
||
and noting all mentions of the registers.
|
||
|
||
Also find where each hard register is live
|
||
and record that info in after_insn_hard_regs.
|
||
regs_live[I] is 1 if hard reg I is live
|
||
at the current point in the scan.
|
||
|
||
Build reload_insn_chain while we're walking the insns. */
|
||
|
||
reload_insn_chain = 0;
|
||
for (insn = last; insn; insn = PREV_INSN (insn))
|
||
{
|
||
register HARD_REG_SET *p = after_insn_hard_regs + INSN_SUID (insn);
|
||
struct insn_chain *chain;
|
||
|
||
/* Copy the info in regs_live into the element of after_insn_hard_regs
|
||
for the current position in the rtl code. */
|
||
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (regs_live[i])
|
||
SET_HARD_REG_BIT (*p, i);
|
||
|
||
if (GET_CODE (insn) != NOTE && GET_CODE (insn) != BARRIER)
|
||
{
|
||
chain = new_insn_chain ();
|
||
if (reload_insn_chain)
|
||
reload_insn_chain->prev = chain;
|
||
chain->next = reload_insn_chain;
|
||
chain->prev = 0;
|
||
reload_insn_chain = chain;
|
||
chain->block = 0;
|
||
chain->insn = insn;
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (regs_live[i])
|
||
SET_REGNO_REG_SET (chain->live_before, i);
|
||
}
|
||
|
||
/* Update which hard regs are currently live
|
||
and also the birth and death suids of pseudo regs
|
||
based on the pattern of this insn. */
|
||
|
||
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
|
||
stupid_mark_refs (PATTERN (insn), chain);
|
||
|
||
if (GET_CODE (insn) == NOTE
|
||
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
|
||
last_setjmp_suid = INSN_SUID (insn);
|
||
|
||
/* Mark all call-clobbered regs as dead after each call insn so that
|
||
a pseudo whose life span includes this insn will not go in one of
|
||
them. If the function contains a non-local goto, mark all hard
|
||
registers dead (except for stack related bits).
|
||
|
||
Then mark those regs as all dead for the continuing scan
|
||
of the insns before the call. */
|
||
|
||
if (GET_CODE (insn) == CALL_INSN)
|
||
{
|
||
last_call_suid = INSN_SUID (insn);
|
||
|
||
if (current_function_has_nonlocal_label)
|
||
{
|
||
IOR_COMPL_HARD_REG_SET (after_insn_hard_regs[last_call_suid],
|
||
fixed_reg_set);
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (! fixed_regs[i])
|
||
regs_live[i] = 0;
|
||
}
|
||
else
|
||
{
|
||
IOR_HARD_REG_SET (after_insn_hard_regs[last_call_suid],
|
||
call_used_reg_set);
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (call_used_regs[i])
|
||
regs_live[i] = 0;
|
||
}
|
||
|
||
/* It is important that this be done after processing the insn's
|
||
pattern because we want the function result register to still
|
||
be live if it's also used to pass arguments. */
|
||
stupid_mark_refs (CALL_INSN_FUNCTION_USAGE (insn), chain);
|
||
}
|
||
|
||
if (GET_CODE (insn) != NOTE && GET_CODE (insn) != BARRIER)
|
||
{
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (regs_live[i])
|
||
SET_REGNO_REG_SET (chain->live_after, i);
|
||
|
||
/* The regs_live array doesn't say anything about hard registers
|
||
clobbered by this insn. So we need an extra pass over the
|
||
pattern. */
|
||
current_chain = chain;
|
||
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
|
||
note_stores (PATTERN (insn), find_clobbered_regs);
|
||
}
|
||
|
||
if (GET_CODE (insn) == JUMP_INSN && computed_jump_p (insn))
|
||
current_function_has_computed_jump = 1;
|
||
}
|
||
|
||
/* Now decide the order in which to allocate the pseudo registers. */
|
||
|
||
for (i = LAST_VIRTUAL_REGISTER + 1; i < max_regno; i++)
|
||
reg_order[i] = i;
|
||
|
||
qsort (®_order[LAST_VIRTUAL_REGISTER + 1],
|
||
max_regno - LAST_VIRTUAL_REGISTER - 1, sizeof (int),
|
||
stupid_reg_compare);
|
||
|
||
/* Now, in that order, try to find hard registers for those pseudo regs. */
|
||
|
||
for (i = LAST_VIRTUAL_REGISTER + 1; i < max_regno; i++)
|
||
{
|
||
register int r = reg_order[i];
|
||
|
||
/* Some regnos disappear from the rtl. Ignore them to avoid crash.
|
||
Also don't allocate registers that cross a setjmp, or live across
|
||
a call if this function receives a nonlocal goto.
|
||
Also ignore registers we didn't see during the scan. */
|
||
if (regno_reg_rtx[r] == 0 || regs_crosses_setjmp[r]
|
||
|| (reg_where_born_exact[r] == 0 && reg_where_dead[r] == 0)
|
||
|| (REG_N_CALLS_CROSSED (r) > 0
|
||
&& current_function_has_nonlocal_label))
|
||
continue;
|
||
|
||
/* Now find the best hard-register class for this pseudo register */
|
||
if (N_REG_CLASSES > 1)
|
||
reg_renumber[r] = stupid_find_reg (REG_N_CALLS_CROSSED (r),
|
||
reg_preferred_class (r),
|
||
PSEUDO_REGNO_MODE (r),
|
||
REG_WHERE_BORN (r),
|
||
reg_where_dead[r],
|
||
regs_change_size[r]);
|
||
|
||
/* If no reg available in that class, try alternate class. */
|
||
if (reg_renumber[r] == -1 && reg_alternate_class (r) != NO_REGS)
|
||
reg_renumber[r] = stupid_find_reg (REG_N_CALLS_CROSSED (r),
|
||
reg_alternate_class (r),
|
||
PSEUDO_REGNO_MODE (r),
|
||
REG_WHERE_BORN (r),
|
||
reg_where_dead[r],
|
||
regs_change_size[r]);
|
||
}
|
||
|
||
/* Fill in the pseudo reg life information into the insn chain. */
|
||
for (i = LAST_VIRTUAL_REGISTER + 1; i < max_regno; i++)
|
||
{
|
||
struct insn_chain *chain;
|
||
int regno;
|
||
|
||
regno = reg_renumber[i];
|
||
if (regno < 0)
|
||
continue;
|
||
|
||
chain = reg_where_dead_chain[i];
|
||
if (reg_where_dead[i] > INSN_SUID (chain->insn))
|
||
SET_REGNO_REG_SET (chain->live_after, i);
|
||
|
||
while (INSN_SUID (chain->insn) > reg_where_born_exact[i])
|
||
{
|
||
SET_REGNO_REG_SET (chain->live_before, i);
|
||
chain = chain->prev;
|
||
if (!chain)
|
||
break;
|
||
SET_REGNO_REG_SET (chain->live_after, i);
|
||
}
|
||
|
||
if (INSN_SUID (chain->insn) == reg_where_born_exact[i]
|
||
&& reg_where_born_clobber[i])
|
||
SET_REGNO_REG_SET (chain->live_before, i);
|
||
}
|
||
|
||
if (file)
|
||
dump_flow_info (file);
|
||
|
||
free (regs_live);
|
||
free (uid_suid);
|
||
free (reg_where_dead);
|
||
free (reg_where_born_exact);
|
||
free (reg_where_born_clobber);
|
||
free (reg_where_dead_chain);
|
||
free (reg_order);
|
||
free (regs_change_size);
|
||
free (regs_crosses_setjmp);
|
||
free (after_insn_hard_regs);
|
||
}
|
||
|
||
/* Comparison function for qsort.
|
||
Returns -1 (1) if register *R1P is higher priority than *R2P. */
|
||
|
||
static int
|
||
stupid_reg_compare (r1p, r2p)
|
||
const GENERIC_PTR r1p;
|
||
const GENERIC_PTR r2p;
|
||
{
|
||
register int r1 = *(int *)r1p, r2 = *(int *)r2p;
|
||
register int len1 = reg_where_dead[r1] - REG_WHERE_BORN (r1);
|
||
register int len2 = reg_where_dead[r2] - REG_WHERE_BORN (r2);
|
||
int tem;
|
||
|
||
tem = len2 - len1;
|
||
if (tem != 0)
|
||
return tem;
|
||
|
||
tem = REG_N_REFS (r1) - REG_N_REFS (r2);
|
||
if (tem != 0)
|
||
return tem;
|
||
|
||
/* If regs are equally good, sort by regno,
|
||
so that the results of qsort leave nothing to chance. */
|
||
return r1 - r2;
|
||
}
|
||
|
||
/* Find a block of SIZE words of hard registers in reg_class CLASS
|
||
that can hold a value of machine-mode MODE
|
||
(but actually we test only the first of the block for holding MODE)
|
||
currently free from after insn whose suid is BORN_INSN
|
||
through the insn whose suid is DEAD_INSN,
|
||
and return the number of the first of them.
|
||
Return -1 if such a block cannot be found.
|
||
|
||
If CALL_PRESERVED is nonzero, insist on registers preserved
|
||
over subroutine calls, and return -1 if cannot find such.
|
||
|
||
If CHANGES_SIZE is nonzero, it means this register was used as the
|
||
operand of a SUBREG that changes its size. */
|
||
|
||
static int
|
||
stupid_find_reg (call_preserved, class, mode,
|
||
born_insn, dead_insn, changes_size)
|
||
int call_preserved;
|
||
enum reg_class class;
|
||
enum machine_mode mode;
|
||
int born_insn, dead_insn;
|
||
int changes_size ATTRIBUTE_UNUSED;
|
||
{
|
||
register int i, ins;
|
||
#ifdef HARD_REG_SET
|
||
register /* Declare them register if they are scalars. */
|
||
#endif
|
||
HARD_REG_SET used, this_reg;
|
||
#ifdef ELIMINABLE_REGS
|
||
static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
|
||
#endif
|
||
|
||
/* If this register's life is more than 5,000 insns, we probably
|
||
can't allocate it, so don't waste the time trying. This avoids
|
||
quadratic behavior on programs that have regularly-occurring
|
||
SAVE_EXPRs. */
|
||
if (dead_insn > born_insn + 5000)
|
||
return -1;
|
||
|
||
COPY_HARD_REG_SET (used,
|
||
call_preserved ? call_used_reg_set : fixed_reg_set);
|
||
|
||
#ifdef ELIMINABLE_REGS
|
||
for (i = 0; i < (int)(sizeof eliminables / sizeof eliminables[0]); i++)
|
||
SET_HARD_REG_BIT (used, eliminables[i].from);
|
||
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
|
||
SET_HARD_REG_BIT (used, HARD_FRAME_POINTER_REGNUM);
|
||
#endif
|
||
#else
|
||
SET_HARD_REG_BIT (used, FRAME_POINTER_REGNUM);
|
||
#endif
|
||
|
||
for (ins = born_insn; ins < dead_insn; ins++)
|
||
IOR_HARD_REG_SET (used, after_insn_hard_regs[ins]);
|
||
|
||
#ifdef STACK_REGS
|
||
if (current_function_has_computed_jump)
|
||
for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
|
||
SET_HARD_REG_BIT (used, i);
|
||
#endif
|
||
|
||
IOR_COMPL_HARD_REG_SET (used, reg_class_contents[(int) class]);
|
||
|
||
#ifdef CLASS_CANNOT_CHANGE_SIZE
|
||
if (changes_size)
|
||
IOR_HARD_REG_SET (used,
|
||
reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE]);
|
||
#endif
|
||
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
{
|
||
#ifdef REG_ALLOC_ORDER
|
||
int regno = reg_alloc_order[i];
|
||
#else
|
||
int regno = i;
|
||
#endif
|
||
|
||
/* If a register has screwy overlap problems,
|
||
don't use it at all if not optimizing.
|
||
Actually this is only for the 387 stack register,
|
||
and it's because subsequent code won't work. */
|
||
#ifdef OVERLAPPING_REGNO_P
|
||
if (OVERLAPPING_REGNO_P (regno))
|
||
continue;
|
||
#endif
|
||
|
||
if (! TEST_HARD_REG_BIT (used, regno)
|
||
&& HARD_REGNO_MODE_OK (regno, mode))
|
||
{
|
||
register int j;
|
||
register int size1 = HARD_REGNO_NREGS (regno, mode);
|
||
for (j = 1; j < size1 && ! TEST_HARD_REG_BIT (used, regno + j); j++);
|
||
if (j == size1)
|
||
{
|
||
CLEAR_HARD_REG_SET (this_reg);
|
||
while (--j >= 0)
|
||
SET_HARD_REG_BIT (this_reg, regno + j);
|
||
for (ins = born_insn; ins < dead_insn; ins++)
|
||
{
|
||
IOR_HARD_REG_SET (after_insn_hard_regs[ins], this_reg);
|
||
}
|
||
return regno;
|
||
}
|
||
#ifndef REG_ALLOC_ORDER
|
||
i += j; /* Skip starting points we know will lose */
|
||
#endif
|
||
}
|
||
}
|
||
|
||
return -1;
|
||
}
|
||
|
||
/* Walk X, noting all assignments and references to registers
|
||
and recording what they imply about life spans.
|
||
INSN is the current insn, supplied so we can find its suid. */
|
||
|
||
static void
|
||
stupid_mark_refs (x, chain)
|
||
rtx x;
|
||
struct insn_chain *chain;
|
||
{
|
||
register RTX_CODE code;
|
||
register char *fmt;
|
||
register int regno, i;
|
||
rtx insn = chain->insn;
|
||
|
||
if (x == 0)
|
||
return;
|
||
|
||
code = GET_CODE (x);
|
||
|
||
if (code == SET || code == CLOBBER)
|
||
{
|
||
if (SET_DEST (x) != 0
|
||
&& (GET_CODE (SET_DEST (x)) == REG
|
||
|| (GET_CODE (SET_DEST (x)) == SUBREG
|
||
&& GET_CODE (SUBREG_REG (SET_DEST (x))) == REG
|
||
&& (REGNO (SUBREG_REG (SET_DEST (x)))
|
||
>= FIRST_PSEUDO_REGISTER))))
|
||
{
|
||
/* Register is being assigned. */
|
||
/* If setting a SUBREG, we treat the entire reg as being set. */
|
||
if (GET_CODE (SET_DEST (x)) == SUBREG)
|
||
regno = REGNO (SUBREG_REG (SET_DEST (x)));
|
||
else
|
||
regno = REGNO (SET_DEST (x));
|
||
|
||
/* For hard regs, update the where-live info. */
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
register int j
|
||
= HARD_REGNO_NREGS (regno, GET_MODE (SET_DEST (x)));
|
||
|
||
while (--j >= 0)
|
||
{
|
||
regs_ever_live[regno+j] = 1;
|
||
regs_live[regno+j] = 0;
|
||
|
||
/* The following line is for unused outputs;
|
||
they do get stored even though never used again. */
|
||
MARK_LIVE_AFTER (insn, regno+j);
|
||
|
||
/* When a hard reg is clobbered, mark it in use
|
||
just before this insn, so it is live all through. */
|
||
if (code == CLOBBER && INSN_SUID (insn) > 0)
|
||
SET_HARD_REG_BIT (after_insn_hard_regs[INSN_SUID (insn) - 1],
|
||
regno+j);
|
||
}
|
||
}
|
||
/* For pseudo regs, record where born, where dead, number of
|
||
times used, and whether live across a call. */
|
||
else
|
||
{
|
||
/* Update the life-interval bounds of this pseudo reg. */
|
||
|
||
/* When a pseudo-reg is CLOBBERed, it is born just before
|
||
the clobbering insn. When setting, just after. */
|
||
int where_born = INSN_SUID (insn) - (code == CLOBBER);
|
||
|
||
reg_where_born_exact[regno] = INSN_SUID (insn);
|
||
reg_where_born_clobber[regno] = (code == CLOBBER);
|
||
|
||
if (reg_where_dead_chain[regno] == 0)
|
||
reg_where_dead_chain[regno] = chain;
|
||
|
||
/* The reg must live at least one insn even
|
||
in it is never again used--because it has to go
|
||
in SOME hard reg. Mark it as dying after the current
|
||
insn so that it will conflict with any other outputs of
|
||
this insn. */
|
||
if (reg_where_dead[regno] < where_born + 2)
|
||
{
|
||
reg_where_dead[regno] = where_born + 2;
|
||
regs_live[regno] = 1;
|
||
}
|
||
|
||
/* Count the refs of this reg. */
|
||
REG_N_REFS (regno)++;
|
||
|
||
if (last_call_suid < reg_where_dead[regno])
|
||
REG_N_CALLS_CROSSED (regno) += 1;
|
||
|
||
if (last_setjmp_suid < reg_where_dead[regno])
|
||
regs_crosses_setjmp[regno] = 1;
|
||
|
||
/* If this register is clobbered or it is only used in
|
||
this insn and is only set, mark it unused. We have
|
||
to do this even when not optimizing so that MD patterns
|
||
which count on this behavior (e.g., it not causing an
|
||
output reload on an insn setting CC) will operate
|
||
correctly. */
|
||
if (GET_CODE (SET_DEST (x)) == REG
|
||
&& (code == CLOBBER
|
||
|| (REGNO_FIRST_UID (regno) == INSN_UID (insn)
|
||
&& REGNO_LAST_UID (regno) == INSN_UID (insn)
|
||
&& ! reg_mentioned_p (SET_DEST (x),
|
||
SET_SRC (x)))))
|
||
REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_UNUSED,
|
||
SET_DEST (x),
|
||
REG_NOTES (insn));
|
||
}
|
||
}
|
||
|
||
/* Record references from the value being set,
|
||
or from addresses in the place being set if that's not a reg.
|
||
If setting a SUBREG, we treat the entire reg as *used*. */
|
||
if (code == SET)
|
||
{
|
||
stupid_mark_refs (SET_SRC (x), chain);
|
||
if (GET_CODE (SET_DEST (x)) != REG)
|
||
stupid_mark_refs (SET_DEST (x), chain);
|
||
}
|
||
return;
|
||
}
|
||
|
||
else if (code == SUBREG
|
||
&& GET_CODE (SUBREG_REG (x)) == REG
|
||
&& REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
|
||
&& (GET_MODE_SIZE (GET_MODE (x))
|
||
!= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
|
||
&& (INTEGRAL_MODE_P (GET_MODE (x))
|
||
|| INTEGRAL_MODE_P (GET_MODE (SUBREG_REG (x)))))
|
||
regs_change_size[REGNO (SUBREG_REG (x))] = 1;
|
||
|
||
/* Register value being used, not set. */
|
||
|
||
else if (code == REG)
|
||
{
|
||
regno = REGNO (x);
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
/* Hard reg: mark it live for continuing scan of previous insns. */
|
||
register int j = HARD_REGNO_NREGS (regno, GET_MODE (x));
|
||
while (--j >= 0)
|
||
{
|
||
regs_ever_live[regno+j] = 1;
|
||
regs_live[regno+j] = 1;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* Pseudo reg: record first use, last use and number of uses. */
|
||
|
||
reg_where_born_exact[regno] = INSN_SUID (insn);
|
||
reg_where_born_clobber[regno] = 0;
|
||
REG_N_REFS (regno)++;
|
||
if (regs_live[regno] == 0)
|
||
{
|
||
regs_live[regno] = 1;
|
||
reg_where_dead[regno] = INSN_SUID (insn);
|
||
reg_where_dead_chain[regno] = chain;
|
||
}
|
||
}
|
||
return;
|
||
}
|
||
|
||
/* Recursive scan of all other rtx's. */
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
stupid_mark_refs (XEXP (x, i), chain);
|
||
if (fmt[i] == 'E')
|
||
{
|
||
register int j;
|
||
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
|
||
stupid_mark_refs (XVECEXP (x, i, j), chain);
|
||
}
|
||
}
|
||
}
|