5304 lines
149 KiB
C
5304 lines
149 KiB
C
/* Data flow analysis for GNU compiler.
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Copyright (C) 1987, 88, 92-98, 1999 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* This file contains the data flow analysis pass of the compiler. It
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computes data flow information which tells combine_instructions
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which insns to consider combining and controls register allocation.
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Additional data flow information that is too bulky to record is
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generated during the analysis, and is used at that time to create
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autoincrement and autodecrement addressing.
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The first step is dividing the function into basic blocks.
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find_basic_blocks does this. Then life_analysis determines
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where each register is live and where it is dead.
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** find_basic_blocks **
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find_basic_blocks divides the current function's rtl into basic
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blocks and constructs the CFG. The blocks are recorded in the
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basic_block_info array; the CFG exists in the edge structures
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referenced by the blocks.
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find_basic_blocks also finds any unreachable loops and deletes them.
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** life_analysis **
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life_analysis is called immediately after find_basic_blocks.
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It uses the basic block information to determine where each
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hard or pseudo register is live.
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** live-register info **
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The information about where each register is live is in two parts:
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the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
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basic_block->global_live_at_start has an element for each basic
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block, and the element is a bit-vector with a bit for each hard or
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pseudo register. The bit is 1 if the register is live at the
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beginning of the basic block.
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Two types of elements can be added to an insn's REG_NOTES.
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A REG_DEAD note is added to an insn's REG_NOTES for any register
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that meets both of two conditions: The value in the register is not
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needed in subsequent insns and the insn does not replace the value in
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the register (in the case of multi-word hard registers, the value in
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each register must be replaced by the insn to avoid a REG_DEAD note).
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In the vast majority of cases, an object in a REG_DEAD note will be
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used somewhere in the insn. The (rare) exception to this is if an
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insn uses a multi-word hard register and only some of the registers are
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needed in subsequent insns. In that case, REG_DEAD notes will be
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provided for those hard registers that are not subsequently needed.
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Partial REG_DEAD notes of this type do not occur when an insn sets
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only some of the hard registers used in such a multi-word operand;
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omitting REG_DEAD notes for objects stored in an insn is optional and
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the desire to do so does not justify the complexity of the partial
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REG_DEAD notes.
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REG_UNUSED notes are added for each register that is set by the insn
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but is unused subsequently (if every register set by the insn is unused
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and the insn does not reference memory or have some other side-effect,
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the insn is deleted instead). If only part of a multi-word hard
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register is used in a subsequent insn, REG_UNUSED notes are made for
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the parts that will not be used.
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To determine which registers are live after any insn, one can
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start from the beginning of the basic block and scan insns, noting
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which registers are set by each insn and which die there.
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** Other actions of life_analysis **
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life_analysis sets up the LOG_LINKS fields of insns because the
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information needed to do so is readily available.
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life_analysis deletes insns whose only effect is to store a value
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that is never used.
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life_analysis notices cases where a reference to a register as
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a memory address can be combined with a preceding or following
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incrementation or decrementation of the register. The separate
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instruction to increment or decrement is deleted and the address
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is changed to a POST_INC or similar rtx.
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Each time an incrementing or decrementing address is created,
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a REG_INC element is added to the insn's REG_NOTES list.
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life_analysis fills in certain vectors containing information about
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register usage: reg_n_refs, reg_n_deaths, reg_n_sets, reg_live_length,
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reg_n_calls_crosses and reg_basic_block.
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life_analysis sets current_function_sp_is_unchanging if the function
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doesn't modify the stack pointer. */
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/* TODO:
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Split out from life_analysis:
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- local property discovery (bb->local_live, bb->local_set)
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- global property computation
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- log links creation
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- pre/post modify transformation
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*/
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#include "config.h"
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#include "system.h"
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#include "rtl.h"
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#include "basic-block.h"
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#include "insn-config.h"
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#include "regs.h"
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#include "hard-reg-set.h"
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#include "flags.h"
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#include "output.h"
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#include "except.h"
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#include "toplev.h"
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#include "recog.h"
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#include "insn-flags.h"
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#include "obstack.h"
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#define obstack_chunk_alloc xmalloc
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#define obstack_chunk_free free
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/* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
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the stack pointer does not matter. The value is tested only in
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functions that have frame pointers.
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No definition is equivalent to always zero. */
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#ifndef EXIT_IGNORE_STACK
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#define EXIT_IGNORE_STACK 0
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#endif
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/* The contents of the current function definition are allocated
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in this obstack, and all are freed at the end of the function.
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For top-level functions, this is temporary_obstack.
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Separate obstacks are made for nested functions. */
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extern struct obstack *function_obstack;
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/* List of labels that must never be deleted. */
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extern rtx forced_labels;
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/* Number of basic blocks in the current function. */
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int n_basic_blocks;
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/* The basic block array. */
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varray_type basic_block_info;
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/* The special entry and exit blocks. */
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struct basic_block_def entry_exit_blocks[2] =
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{
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{
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NULL, /* head */
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NULL, /* end */
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NULL, /* pred */
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NULL, /* succ */
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NULL, /* local_set */
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NULL, /* global_live_at_start */
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NULL, /* global_live_at_end */
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NULL, /* aux */
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ENTRY_BLOCK, /* index */
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0 /* loop_depth */
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},
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{
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NULL, /* head */
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NULL, /* end */
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NULL, /* pred */
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NULL, /* succ */
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NULL, /* local_set */
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NULL, /* global_live_at_start */
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NULL, /* global_live_at_end */
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NULL, /* aux */
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EXIT_BLOCK, /* index */
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0 /* loop_depth */
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}
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};
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/* Nonzero if the second flow pass has completed. */
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int flow2_completed;
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/* Maximum register number used in this function, plus one. */
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int max_regno;
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/* Indexed by n, giving various register information */
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varray_type reg_n_info;
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/* Size of the reg_n_info table. */
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unsigned int reg_n_max;
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/* Element N is the next insn that uses (hard or pseudo) register number N
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within the current basic block; or zero, if there is no such insn.
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This is valid only during the final backward scan in propagate_block. */
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static rtx *reg_next_use;
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/* Size of a regset for the current function,
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in (1) bytes and (2) elements. */
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int regset_bytes;
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int regset_size;
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/* Regset of regs live when calls to `setjmp'-like functions happen. */
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/* ??? Does this exist only for the setjmp-clobbered warning message? */
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regset regs_live_at_setjmp;
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/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
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that have to go in the same hard reg.
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The first two regs in the list are a pair, and the next two
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are another pair, etc. */
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rtx regs_may_share;
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/* Depth within loops of basic block being scanned for lifetime analysis,
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plus one. This is the weight attached to references to registers. */
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static int loop_depth;
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/* During propagate_block, this is non-zero if the value of CC0 is live. */
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static int cc0_live;
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/* During propagate_block, this contains a list of all the MEMs we are
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tracking for dead store elimination.
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?!? Note we leak memory by not free-ing items on this list. We need to
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write some generic routines to operate on memory lists since cse, gcse,
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loop, sched, flow and possibly other passes all need to do basically the
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same operations on these lists. */
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static rtx mem_set_list;
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/* Set of registers that may be eliminable. These are handled specially
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in updating regs_ever_live. */
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static HARD_REG_SET elim_reg_set;
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/* The basic block structure for every insn, indexed by uid. */
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varray_type basic_block_for_insn;
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/* The labels mentioned in non-jump rtl. Valid during find_basic_blocks. */
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/* ??? Should probably be using LABEL_NUSES instead. It would take a
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bit of surgery to be able to use or co-opt the routines in jump. */
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static rtx label_value_list;
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/* INSN_VOLATILE (insn) is 1 if the insn refers to anything volatile. */
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#define INSN_VOLATILE(INSN) bitmap_bit_p (uid_volatile, INSN_UID (INSN))
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#define SET_INSN_VOLATILE(INSN) bitmap_set_bit (uid_volatile, INSN_UID (INSN))
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static bitmap uid_volatile;
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/* Forward declarations */
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static int count_basic_blocks PROTO((rtx));
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static rtx find_basic_blocks_1 PROTO((rtx, rtx*));
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static void create_basic_block PROTO((int, rtx, rtx, rtx));
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static void compute_bb_for_insn PROTO((varray_type, int));
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static void clear_edges PROTO((void));
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static void make_edges PROTO((rtx, rtx*));
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static void make_edge PROTO((basic_block, basic_block, int));
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static void make_label_edge PROTO((basic_block, rtx, int));
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static void mark_critical_edges PROTO((void));
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static void commit_one_edge_insertion PROTO((edge));
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static void delete_unreachable_blocks PROTO((void));
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static void delete_eh_regions PROTO((void));
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static int can_delete_note_p PROTO((rtx));
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static void delete_insn_chain PROTO((rtx, rtx));
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static int delete_block PROTO((basic_block));
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static void expunge_block PROTO((basic_block));
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static rtx flow_delete_insn PROTO((rtx));
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static int can_delete_label_p PROTO((rtx));
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static void merge_blocks_nomove PROTO((basic_block, basic_block));
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static int merge_blocks PROTO((edge,basic_block,basic_block));
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static void tidy_fallthru_edge PROTO((edge,basic_block,basic_block));
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static void calculate_loop_depth PROTO((rtx));
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static int set_noop_p PROTO((rtx));
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static int noop_move_p PROTO((rtx));
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static void notice_stack_pointer_modification PROTO ((rtx, rtx));
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static void record_volatile_insns PROTO((rtx));
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static void mark_regs_live_at_end PROTO((regset));
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static void life_analysis_1 PROTO((rtx, int, int));
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static void init_regset_vector PROTO ((regset *, int,
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struct obstack *));
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static void propagate_block PROTO((regset, rtx, rtx, int,
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regset, int, int));
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static int insn_dead_p PROTO((rtx, regset, int, rtx));
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static int libcall_dead_p PROTO((rtx, regset, rtx, rtx));
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static void mark_set_regs PROTO((regset, regset, rtx,
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rtx, regset));
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static void mark_set_1 PROTO((regset, regset, rtx,
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rtx, regset));
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#ifdef AUTO_INC_DEC
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static void find_auto_inc PROTO((regset, rtx, rtx));
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static int try_pre_increment_1 PROTO((rtx));
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static int try_pre_increment PROTO((rtx, rtx, HOST_WIDE_INT));
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#endif
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static void mark_used_regs PROTO((regset, regset, rtx, int, rtx));
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void dump_flow_info PROTO((FILE *));
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static void dump_edge_info PROTO((FILE *, edge, int));
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static int_list_ptr alloc_int_list_node PROTO ((int_list_block **));
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static int_list_ptr add_int_list_node PROTO ((int_list_block **,
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int_list **, int));
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static void add_pred_succ PROTO ((int, int, int_list_ptr *,
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int_list_ptr *, int *, int *));
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static void count_reg_sets_1 PROTO ((rtx));
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static void count_reg_sets PROTO ((rtx));
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static void count_reg_references PROTO ((rtx));
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static void notice_stack_pointer_modification PROTO ((rtx, rtx));
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static void invalidate_mems_from_autoinc PROTO ((rtx));
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void verify_flow_info PROTO ((void));
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/* Find basic blocks of the current function.
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F is the first insn of the function and NREGS the number of register
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numbers in use. */
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void
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find_basic_blocks (f, nregs, file, do_cleanup)
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rtx f;
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int nregs ATTRIBUTE_UNUSED;
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FILE *file ATTRIBUTE_UNUSED;
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int do_cleanup;
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{
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rtx *bb_eh_end;
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int max_uid;
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/* Flush out existing data. */
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if (basic_block_info != NULL)
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{
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int i;
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clear_edges ();
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/* Clear bb->aux on all extant basic blocks. We'll use this as a
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tag for reuse during create_basic_block, just in case some pass
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copies around basic block notes improperly. */
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for (i = 0; i < n_basic_blocks; ++i)
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BASIC_BLOCK (i)->aux = NULL;
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VARRAY_FREE (basic_block_info);
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}
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n_basic_blocks = count_basic_blocks (f);
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/* Size the basic block table. The actual structures will be allocated
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by find_basic_blocks_1, since we want to keep the structure pointers
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||
stable across calls to find_basic_blocks. */
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/* ??? This whole issue would be much simpler if we called find_basic_blocks
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exactly once, and thereafter we don't have a single long chain of
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instructions at all until close to the end of compilation when we
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actually lay them out. */
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VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info");
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/* An array to record the active exception region at the end of each
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basic block. It is filled in by find_basic_blocks_1 for make_edges. */
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bb_eh_end = (rtx *) alloca (n_basic_blocks * sizeof (rtx));
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label_value_list = find_basic_blocks_1 (f, bb_eh_end);
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||
|
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/* Record the block to which an insn belongs. */
|
||
/* ??? This should be done another way, by which (perhaps) a label is
|
||
tagged directly with the basic block that it starts. It is used for
|
||
more than that currently, but IMO that is the only valid use. */
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||
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||
max_uid = get_max_uid ();
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||
#ifdef AUTO_INC_DEC
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||
/* Leave space for insns life_analysis makes in some cases for auto-inc.
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||
These cases are rare, so we don't need too much space. */
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max_uid += max_uid / 10;
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||
#endif
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||
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||
VARRAY_BB_INIT (basic_block_for_insn, max_uid, "basic_block_for_insn");
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||
compute_bb_for_insn (basic_block_for_insn, max_uid);
|
||
|
||
/* Discover the edges of our cfg. */
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||
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make_edges (label_value_list, bb_eh_end);
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||
|
||
/* Delete unreachable blocks. */
|
||
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||
if (do_cleanup)
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delete_unreachable_blocks ();
|
||
|
||
/* Mark critical edges. */
|
||
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mark_critical_edges ();
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||
|
||
/* Discover the loop depth at the start of each basic block to aid
|
||
register allocation. */
|
||
calculate_loop_depth (f);
|
||
|
||
/* Kill the data we won't maintain. */
|
||
label_value_list = 0;
|
||
|
||
#ifdef ENABLE_CHECKING
|
||
verify_flow_info ();
|
||
#endif
|
||
}
|
||
|
||
/* Count the basic blocks of the function. */
|
||
|
||
static int
|
||
count_basic_blocks (f)
|
||
rtx f;
|
||
{
|
||
register rtx insn;
|
||
register RTX_CODE prev_code;
|
||
register int count = 0;
|
||
int eh_region = 0;
|
||
int call_had_abnormal_edge = 0;
|
||
rtx prev_call = NULL_RTX;
|
||
|
||
prev_code = JUMP_INSN;
|
||
for (insn = f; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
register RTX_CODE code = GET_CODE (insn);
|
||
|
||
if (code == CODE_LABEL
|
||
|| (GET_RTX_CLASS (code) == 'i'
|
||
&& (prev_code == JUMP_INSN
|
||
|| prev_code == BARRIER
|
||
|| (prev_code == CALL_INSN && call_had_abnormal_edge))))
|
||
{
|
||
count++;
|
||
|
||
/* If the previous insn was a call that did not create an
|
||
abnormal edge, we want to add a nop so that the CALL_INSN
|
||
itself is not at basic_block_end. This allows us to
|
||
easily distinguish between normal calls and those which
|
||
create abnormal edges in the flow graph. */
|
||
|
||
if (count > 0 && prev_call != 0 && !call_had_abnormal_edge)
|
||
{
|
||
rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
|
||
emit_insn_after (nop, prev_call);
|
||
}
|
||
}
|
||
|
||
/* Record whether this call created an edge. */
|
||
if (code == CALL_INSN)
|
||
{
|
||
rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
|
||
int region = (note ? XINT (XEXP (note, 0), 0) : 1);
|
||
prev_call = insn;
|
||
call_had_abnormal_edge = 0;
|
||
|
||
/* If there is a specified EH region, we have an edge. */
|
||
if (eh_region && region > 0)
|
||
call_had_abnormal_edge = 1;
|
||
else
|
||
{
|
||
/* If there is a nonlocal goto label and the specified
|
||
region number isn't -1, we have an edge. (0 means
|
||
no throw, but might have a nonlocal goto). */
|
||
if (nonlocal_goto_handler_labels && region >= 0)
|
||
call_had_abnormal_edge = 1;
|
||
}
|
||
}
|
||
else if (code != NOTE)
|
||
prev_call = NULL_RTX;
|
||
|
||
if (code != NOTE)
|
||
prev_code = code;
|
||
else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
|
||
++eh_region;
|
||
else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
|
||
--eh_region;
|
||
|
||
}
|
||
|
||
/* The rest of the compiler works a bit smoother when we don't have to
|
||
check for the edge case of do-nothing functions with no basic blocks. */
|
||
if (count == 0)
|
||
{
|
||
emit_insn (gen_rtx_USE (VOIDmode, const0_rtx));
|
||
count = 1;
|
||
}
|
||
|
||
return count;
|
||
}
|
||
|
||
/* Find all basic blocks of the function whose first insn is F.
|
||
Store the correct data in the tables that describe the basic blocks,
|
||
set up the chains of references for each CODE_LABEL, and
|
||
delete any entire basic blocks that cannot be reached.
|
||
|
||
NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
|
||
that are otherwise unreachable may be reachable with a non-local goto.
|
||
|
||
BB_EH_END is an array in which we record the list of exception regions
|
||
active at the end of every basic block. */
|
||
|
||
static rtx
|
||
find_basic_blocks_1 (f, bb_eh_end)
|
||
rtx f;
|
||
rtx *bb_eh_end;
|
||
{
|
||
register rtx insn, next;
|
||
int call_has_abnormal_edge = 0;
|
||
int i = 0;
|
||
rtx bb_note = NULL_RTX;
|
||
rtx eh_list = NULL_RTX;
|
||
rtx label_value_list = NULL_RTX;
|
||
rtx head = NULL_RTX;
|
||
rtx end = NULL_RTX;
|
||
|
||
/* We process the instructions in a slightly different way than we did
|
||
previously. This is so that we see a NOTE_BASIC_BLOCK after we have
|
||
closed out the previous block, so that it gets attached at the proper
|
||
place. Since this form should be equivalent to the previous,
|
||
find_basic_blocks_0 continues to use the old form as a check. */
|
||
|
||
for (insn = f; insn; insn = next)
|
||
{
|
||
enum rtx_code code = GET_CODE (insn);
|
||
|
||
next = NEXT_INSN (insn);
|
||
|
||
if (code == CALL_INSN)
|
||
{
|
||
/* Record whether this call created an edge. */
|
||
rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
|
||
int region = (note ? XINT (XEXP (note, 0), 0) : 1);
|
||
call_has_abnormal_edge = 0;
|
||
|
||
/* If there is an EH region, we have an edge. */
|
||
if (eh_list && region > 0)
|
||
call_has_abnormal_edge = 1;
|
||
else
|
||
{
|
||
/* If there is a nonlocal goto label and the specified
|
||
region number isn't -1, we have an edge. (0 means
|
||
no throw, but might have a nonlocal goto). */
|
||
if (nonlocal_goto_handler_labels && region >= 0)
|
||
call_has_abnormal_edge = 1;
|
||
}
|
||
}
|
||
|
||
switch (code)
|
||
{
|
||
case NOTE:
|
||
{
|
||
int kind = NOTE_LINE_NUMBER (insn);
|
||
|
||
/* Keep a LIFO list of the currently active exception notes. */
|
||
if (kind == NOTE_INSN_EH_REGION_BEG)
|
||
eh_list = gen_rtx_INSN_LIST (VOIDmode, insn, eh_list);
|
||
else if (kind == NOTE_INSN_EH_REGION_END)
|
||
eh_list = XEXP (eh_list, 1);
|
||
|
||
/* Look for basic block notes with which to keep the
|
||
basic_block_info pointers stable. Unthread the note now;
|
||
we'll put it back at the right place in create_basic_block.
|
||
Or not at all if we've already found a note in this block. */
|
||
else if (kind == NOTE_INSN_BASIC_BLOCK)
|
||
{
|
||
if (bb_note == NULL_RTX)
|
||
bb_note = insn;
|
||
next = flow_delete_insn (insn);
|
||
}
|
||
|
||
break;
|
||
}
|
||
|
||
case CODE_LABEL:
|
||
/* A basic block starts at a label. If we've closed one off due
|
||
to a barrier or some such, no need to do it again. */
|
||
if (head != NULL_RTX)
|
||
{
|
||
/* While we now have edge lists with which other portions of
|
||
the compiler might determine a call ending a basic block
|
||
does not imply an abnormal edge, it will be a bit before
|
||
everything can be updated. So continue to emit a noop at
|
||
the end of such a block. */
|
||
if (GET_CODE (end) == CALL_INSN)
|
||
{
|
||
rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
|
||
end = emit_insn_after (nop, end);
|
||
}
|
||
|
||
bb_eh_end[i] = eh_list;
|
||
create_basic_block (i++, head, end, bb_note);
|
||
bb_note = NULL_RTX;
|
||
}
|
||
head = end = insn;
|
||
break;
|
||
|
||
case JUMP_INSN:
|
||
/* A basic block ends at a jump. */
|
||
if (head == NULL_RTX)
|
||
head = insn;
|
||
else
|
||
{
|
||
/* ??? Make a special check for table jumps. The way this
|
||
happens is truely and amazingly gross. We are about to
|
||
create a basic block that contains just a code label and
|
||
an addr*vec jump insn. Worse, an addr_diff_vec creates
|
||
its own natural loop.
|
||
|
||
Prevent this bit of brain damage, pasting things together
|
||
correctly in make_edges.
|
||
|
||
The correct solution involves emitting the table directly
|
||
on the tablejump instruction as a note, or JUMP_LABEL. */
|
||
|
||
if (GET_CODE (PATTERN (insn)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
|
||
{
|
||
head = end = NULL;
|
||
n_basic_blocks--;
|
||
break;
|
||
}
|
||
}
|
||
end = insn;
|
||
goto new_bb_inclusive;
|
||
|
||
case BARRIER:
|
||
/* A basic block ends at a barrier. It may be that an unconditional
|
||
jump already closed the basic block -- no need to do it again. */
|
||
if (head == NULL_RTX)
|
||
break;
|
||
|
||
/* While we now have edge lists with which other portions of the
|
||
compiler might determine a call ending a basic block does not
|
||
imply an abnormal edge, it will be a bit before everything can
|
||
be updated. So continue to emit a noop at the end of such a
|
||
block. */
|
||
if (GET_CODE (end) == CALL_INSN)
|
||
{
|
||
rtx nop = gen_rtx_USE (VOIDmode, const0_rtx);
|
||
end = emit_insn_after (nop, end);
|
||
}
|
||
goto new_bb_exclusive;
|
||
|
||
case CALL_INSN:
|
||
/* A basic block ends at a call that can either throw or
|
||
do a non-local goto. */
|
||
if (call_has_abnormal_edge)
|
||
{
|
||
new_bb_inclusive:
|
||
if (head == NULL_RTX)
|
||
head = insn;
|
||
end = insn;
|
||
|
||
new_bb_exclusive:
|
||
bb_eh_end[i] = eh_list;
|
||
create_basic_block (i++, head, end, bb_note);
|
||
head = end = NULL_RTX;
|
||
bb_note = NULL_RTX;
|
||
break;
|
||
}
|
||
/* FALLTHRU */
|
||
|
||
default:
|
||
if (GET_RTX_CLASS (code) == 'i')
|
||
{
|
||
if (head == NULL_RTX)
|
||
head = insn;
|
||
end = insn;
|
||
}
|
||
break;
|
||
}
|
||
|
||
if (GET_RTX_CLASS (code) == 'i')
|
||
{
|
||
rtx note;
|
||
|
||
/* Make a list of all labels referred to other than by jumps
|
||
(which just don't have the REG_LABEL notes).
|
||
|
||
Make a special exception for labels followed by an ADDR*VEC,
|
||
as this would be a part of the tablejump setup code.
|
||
|
||
Make a special exception for the eh_return_stub_label, which
|
||
we know isn't part of any otherwise visible control flow. */
|
||
|
||
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
|
||
if (REG_NOTE_KIND (note) == REG_LABEL)
|
||
{
|
||
rtx lab = XEXP (note, 0), next;
|
||
|
||
if (lab == eh_return_stub_label)
|
||
;
|
||
else if ((next = next_nonnote_insn (lab)) != NULL
|
||
&& GET_CODE (next) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (next)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
|
||
;
|
||
else
|
||
label_value_list
|
||
= gen_rtx_EXPR_LIST (VOIDmode, XEXP (note, 0),
|
||
label_value_list);
|
||
}
|
||
}
|
||
}
|
||
|
||
if (head != NULL_RTX)
|
||
{
|
||
bb_eh_end[i] = eh_list;
|
||
create_basic_block (i++, head, end, bb_note);
|
||
}
|
||
|
||
if (i != n_basic_blocks)
|
||
abort ();
|
||
|
||
return label_value_list;
|
||
}
|
||
|
||
/* Create a new basic block consisting of the instructions between
|
||
HEAD and END inclusive. Reuses the note and basic block struct
|
||
in BB_NOTE, if any. */
|
||
|
||
static void
|
||
create_basic_block (index, head, end, bb_note)
|
||
int index;
|
||
rtx head, end, bb_note;
|
||
{
|
||
basic_block bb;
|
||
|
||
if (bb_note
|
||
&& ! RTX_INTEGRATED_P (bb_note)
|
||
&& (bb = NOTE_BASIC_BLOCK (bb_note)) != NULL
|
||
&& bb->aux == NULL)
|
||
{
|
||
/* If we found an existing note, thread it back onto the chain. */
|
||
|
||
if (GET_CODE (head) == CODE_LABEL)
|
||
add_insn_after (bb_note, head);
|
||
else
|
||
{
|
||
add_insn_before (bb_note, head);
|
||
head = bb_note;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* Otherwise we must create a note and a basic block structure.
|
||
Since we allow basic block structs in rtl, give the struct
|
||
the same lifetime by allocating it off the function obstack
|
||
rather than using malloc. */
|
||
|
||
bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
|
||
memset (bb, 0, sizeof (*bb));
|
||
|
||
if (GET_CODE (head) == CODE_LABEL)
|
||
bb_note = emit_note_after (NOTE_INSN_BASIC_BLOCK, head);
|
||
else
|
||
{
|
||
bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, head);
|
||
head = bb_note;
|
||
}
|
||
NOTE_BASIC_BLOCK (bb_note) = bb;
|
||
}
|
||
|
||
/* Always include the bb note in the block. */
|
||
if (NEXT_INSN (end) == bb_note)
|
||
end = bb_note;
|
||
|
||
bb->head = head;
|
||
bb->end = end;
|
||
bb->index = index;
|
||
BASIC_BLOCK (index) = bb;
|
||
|
||
/* Tag the block so that we know it has been used when considering
|
||
other basic block notes. */
|
||
bb->aux = bb;
|
||
}
|
||
|
||
/* Records the basic block struct in BB_FOR_INSN, for every instruction
|
||
indexed by INSN_UID. MAX is the size of the array. */
|
||
|
||
static void
|
||
compute_bb_for_insn (bb_for_insn, max)
|
||
varray_type bb_for_insn;
|
||
int max;
|
||
{
|
||
int i;
|
||
|
||
for (i = 0; i < n_basic_blocks; ++i)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
rtx insn, end;
|
||
|
||
end = bb->end;
|
||
insn = bb->head;
|
||
while (1)
|
||
{
|
||
int uid = INSN_UID (insn);
|
||
if (uid < max)
|
||
VARRAY_BB (bb_for_insn, uid) = bb;
|
||
if (insn == end)
|
||
break;
|
||
insn = NEXT_INSN (insn);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Free the memory associated with the edge structures. */
|
||
|
||
static void
|
||
clear_edges ()
|
||
{
|
||
int i;
|
||
edge n, e;
|
||
|
||
for (i = 0; i < n_basic_blocks; ++i)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
for (e = bb->succ; e ; e = n)
|
||
{
|
||
n = e->succ_next;
|
||
free (e);
|
||
}
|
||
|
||
bb->succ = 0;
|
||
bb->pred = 0;
|
||
}
|
||
|
||
for (e = ENTRY_BLOCK_PTR->succ; e ; e = n)
|
||
{
|
||
n = e->succ_next;
|
||
free (e);
|
||
}
|
||
|
||
ENTRY_BLOCK_PTR->succ = 0;
|
||
EXIT_BLOCK_PTR->pred = 0;
|
||
}
|
||
|
||
/* Identify the edges between basic blocks.
|
||
|
||
NONLOCAL_LABEL_LIST is a list of non-local labels in the function. Blocks
|
||
that are otherwise unreachable may be reachable with a non-local goto.
|
||
|
||
BB_EH_END is an array indexed by basic block number in which we record
|
||
the list of exception regions active at the end of the basic block. */
|
||
|
||
static void
|
||
make_edges (label_value_list, bb_eh_end)
|
||
rtx label_value_list;
|
||
rtx *bb_eh_end;
|
||
{
|
||
int i;
|
||
|
||
/* Assume no computed jump; revise as we create edges. */
|
||
current_function_has_computed_jump = 0;
|
||
|
||
/* By nature of the way these get numbered, block 0 is always the entry. */
|
||
make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (0), EDGE_FALLTHRU);
|
||
|
||
for (i = 0; i < n_basic_blocks; ++i)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
rtx insn, x, eh_list;
|
||
enum rtx_code code;
|
||
int force_fallthru = 0;
|
||
|
||
/* If we have asynchronous exceptions, scan the notes for all exception
|
||
regions active in the block. In the normal case, we only need the
|
||
one active at the end of the block, which is bb_eh_end[i]. */
|
||
|
||
eh_list = bb_eh_end[i];
|
||
if (asynchronous_exceptions)
|
||
{
|
||
for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
|
||
{
|
||
if (GET_CODE (insn) == NOTE
|
||
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
|
||
eh_list = gen_rtx_INSN_LIST (VOIDmode, insn, eh_list);
|
||
}
|
||
}
|
||
|
||
/* Now examine the last instruction of the block, and discover the
|
||
ways we can leave the block. */
|
||
|
||
insn = bb->end;
|
||
code = GET_CODE (insn);
|
||
|
||
/* A branch. */
|
||
if (code == JUMP_INSN)
|
||
{
|
||
rtx tmp;
|
||
|
||
/* ??? Recognize a tablejump and do the right thing. */
|
||
if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
|
||
&& (tmp = NEXT_INSN (tmp)) != NULL_RTX
|
||
&& GET_CODE (tmp) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (tmp)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
|
||
{
|
||
rtvec vec;
|
||
int j;
|
||
|
||
if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
|
||
vec = XVEC (PATTERN (tmp), 0);
|
||
else
|
||
vec = XVEC (PATTERN (tmp), 1);
|
||
|
||
for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
|
||
make_label_edge (bb, XEXP (RTVEC_ELT (vec, j), 0), 0);
|
||
|
||
/* Some targets (eg, ARM) emit a conditional jump that also
|
||
contains the out-of-range target. Scan for these and
|
||
add an edge if necessary. */
|
||
if ((tmp = single_set (insn)) != NULL
|
||
&& SET_DEST (tmp) == pc_rtx
|
||
&& GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
|
||
&& GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF)
|
||
make_label_edge (bb, XEXP (XEXP (SET_SRC (tmp), 2), 0), 0);
|
||
|
||
#ifdef CASE_DROPS_THROUGH
|
||
/* Silly VAXen. The ADDR_VEC is going to be in the way of
|
||
us naturally detecting fallthru into the next block. */
|
||
force_fallthru = 1;
|
||
#endif
|
||
}
|
||
|
||
/* If this is a computed jump, then mark it as reaching
|
||
everything on the label_value_list and forced_labels list. */
|
||
else if (computed_jump_p (insn))
|
||
{
|
||
current_function_has_computed_jump = 1;
|
||
|
||
for (x = label_value_list; x; x = XEXP (x, 1))
|
||
make_label_edge (bb, XEXP (x, 0), EDGE_ABNORMAL);
|
||
|
||
for (x = forced_labels; x; x = XEXP (x, 1))
|
||
make_label_edge (bb, XEXP (x, 0), EDGE_ABNORMAL);
|
||
}
|
||
|
||
/* Returns create an exit out. */
|
||
else if (returnjump_p (insn))
|
||
make_edge (bb, EXIT_BLOCK_PTR, 0);
|
||
|
||
/* Otherwise, we have a plain conditional or unconditional jump. */
|
||
else
|
||
{
|
||
if (! JUMP_LABEL (insn))
|
||
abort ();
|
||
make_label_edge (bb, JUMP_LABEL (insn), 0);
|
||
}
|
||
}
|
||
|
||
/* If this is a CALL_INSN, then mark it as reaching the active EH
|
||
handler for this CALL_INSN. If we're handling asynchronous
|
||
exceptions then any insn can reach any of the active handlers.
|
||
|
||
Also mark the CALL_INSN as reaching any nonlocal goto handler. */
|
||
|
||
if (code == CALL_INSN || asynchronous_exceptions)
|
||
{
|
||
int is_call = (code == CALL_INSN ? EDGE_ABNORMAL_CALL : 0);
|
||
handler_info *ptr;
|
||
|
||
/* Use REG_EH_RETHROW and REG_EH_REGION if available. */
|
||
/* ??? REG_EH_REGION is not generated presently. Is it
|
||
inteded that there be multiple notes for the regions?
|
||
or is my eh_list collection redundant with handler linking? */
|
||
|
||
x = find_reg_note (insn, REG_EH_RETHROW, 0);
|
||
if (!x)
|
||
x = find_reg_note (insn, REG_EH_REGION, 0);
|
||
if (x)
|
||
{
|
||
if (XINT (XEXP (x, 0), 0) > 0)
|
||
{
|
||
ptr = get_first_handler (XINT (XEXP (x, 0), 0));
|
||
while (ptr)
|
||
{
|
||
make_label_edge (bb, ptr->handler_label,
|
||
EDGE_ABNORMAL | EDGE_EH | is_call);
|
||
ptr = ptr->next;
|
||
}
|
||
}
|
||
}
|
||
else
|
||
{
|
||
for (x = eh_list; x; x = XEXP (x, 1))
|
||
{
|
||
ptr = get_first_handler (NOTE_BLOCK_NUMBER (XEXP (x, 0)));
|
||
while (ptr)
|
||
{
|
||
make_label_edge (bb, ptr->handler_label,
|
||
EDGE_ABNORMAL | EDGE_EH | is_call);
|
||
ptr = ptr->next;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (code == CALL_INSN && nonlocal_goto_handler_labels)
|
||
{
|
||
/* ??? This could be made smarter: in some cases it's possible
|
||
to tell that certain calls will not do a nonlocal goto.
|
||
|
||
For example, if the nested functions that do the nonlocal
|
||
gotos do not have their addresses taken, then only calls to
|
||
those functions or to other nested functions that use them
|
||
could possibly do nonlocal gotos. */
|
||
|
||
for (x = nonlocal_goto_handler_labels; x ; x = XEXP (x, 1))
|
||
make_label_edge (bb, XEXP (x, 0),
|
||
EDGE_ABNORMAL | EDGE_ABNORMAL_CALL);
|
||
}
|
||
}
|
||
|
||
/* We know something about the structure of the function __throw in
|
||
libgcc2.c. It is the only function that ever contains eh_stub
|
||
labels. It modifies its return address so that the last block
|
||
returns to one of the eh_stub labels within it. So we have to
|
||
make additional edges in the flow graph. */
|
||
if (i + 1 == n_basic_blocks && eh_return_stub_label != 0)
|
||
make_label_edge (bb, eh_return_stub_label, EDGE_EH);
|
||
|
||
/* Find out if we can drop through to the next block. */
|
||
insn = next_nonnote_insn (insn);
|
||
if (!insn || (i + 1 == n_basic_blocks && force_fallthru))
|
||
make_edge (bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU);
|
||
else if (i + 1 < n_basic_blocks)
|
||
{
|
||
rtx tmp = BLOCK_HEAD (i + 1);
|
||
if (GET_CODE (tmp) == NOTE)
|
||
tmp = next_nonnote_insn (tmp);
|
||
if (force_fallthru || insn == tmp)
|
||
make_edge (bb, BASIC_BLOCK (i + 1), EDGE_FALLTHRU);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Create an edge between two basic blocks. FLAGS are auxiliary information
|
||
about the edge that is accumulated between calls. */
|
||
|
||
static void
|
||
make_edge (src, dst, flags)
|
||
basic_block src, dst;
|
||
int flags;
|
||
{
|
||
edge e;
|
||
|
||
/* Make sure we don't add duplicate edges. */
|
||
|
||
for (e = src->succ; e ; e = e->succ_next)
|
||
if (e->dest == dst)
|
||
{
|
||
e->flags |= flags;
|
||
return;
|
||
}
|
||
|
||
e = (edge) xcalloc (1, sizeof (*e));
|
||
|
||
e->succ_next = src->succ;
|
||
e->pred_next = dst->pred;
|
||
e->src = src;
|
||
e->dest = dst;
|
||
e->flags = flags;
|
||
|
||
src->succ = e;
|
||
dst->pred = e;
|
||
}
|
||
|
||
/* Create an edge from a basic block to a label. */
|
||
|
||
static void
|
||
make_label_edge (src, label, flags)
|
||
basic_block src;
|
||
rtx label;
|
||
int flags;
|
||
{
|
||
if (GET_CODE (label) != CODE_LABEL)
|
||
abort ();
|
||
|
||
/* If the label was never emitted, this insn is junk, but avoid a
|
||
crash trying to refer to BLOCK_FOR_INSN (label). This can happen
|
||
as a result of a syntax error and a diagnostic has already been
|
||
printed. */
|
||
|
||
if (INSN_UID (label) == 0)
|
||
return;
|
||
|
||
make_edge (src, BLOCK_FOR_INSN (label), flags);
|
||
}
|
||
|
||
/* Identify critical edges and set the bits appropriately. */
|
||
static void
|
||
mark_critical_edges ()
|
||
{
|
||
int i, n = n_basic_blocks;
|
||
basic_block bb;
|
||
|
||
/* We begin with the entry block. This is not terribly important now,
|
||
but could be if a front end (Fortran) implemented alternate entry
|
||
points. */
|
||
bb = ENTRY_BLOCK_PTR;
|
||
i = -1;
|
||
|
||
while (1)
|
||
{
|
||
edge e;
|
||
|
||
/* (1) Critical edges must have a source with multiple successors. */
|
||
if (bb->succ && bb->succ->succ_next)
|
||
{
|
||
for (e = bb->succ; e ; e = e->succ_next)
|
||
{
|
||
/* (2) Critical edges must have a destination with multiple
|
||
predecessors. Note that we know there is at least one
|
||
predecessor -- the edge we followed to get here. */
|
||
if (e->dest->pred->pred_next)
|
||
e->flags |= EDGE_CRITICAL;
|
||
else
|
||
e->flags &= ~EDGE_CRITICAL;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
for (e = bb->succ; e ; e = e->succ_next)
|
||
e->flags &= ~EDGE_CRITICAL;
|
||
}
|
||
|
||
if (++i >= n)
|
||
break;
|
||
bb = BASIC_BLOCK (i);
|
||
}
|
||
}
|
||
|
||
/* Split a (typically critical) edge. Return the new block.
|
||
Abort on abnormal edges.
|
||
|
||
??? The code generally expects to be called on critical edges.
|
||
The case of a block ending in an unconditional jump to a
|
||
block with multiple predecessors is not handled optimally. */
|
||
|
||
basic_block
|
||
split_edge (edge_in)
|
||
edge edge_in;
|
||
{
|
||
basic_block old_pred, bb, old_succ;
|
||
edge edge_out;
|
||
rtx bb_note;
|
||
int i;
|
||
|
||
/* Abnormal edges cannot be split. */
|
||
if ((edge_in->flags & EDGE_ABNORMAL) != 0)
|
||
abort ();
|
||
|
||
old_pred = edge_in->src;
|
||
old_succ = edge_in->dest;
|
||
|
||
/* Remove the existing edge from the destination's pred list. */
|
||
{
|
||
edge *pp;
|
||
for (pp = &old_succ->pred; *pp != edge_in; pp = &(*pp)->pred_next)
|
||
continue;
|
||
*pp = edge_in->pred_next;
|
||
edge_in->pred_next = NULL;
|
||
}
|
||
|
||
/* Create the new structures. */
|
||
bb = (basic_block) obstack_alloc (function_obstack, sizeof (*bb));
|
||
edge_out = (edge) xcalloc (1, sizeof (*edge_out));
|
||
|
||
memset (bb, 0, sizeof (*bb));
|
||
bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
|
||
/* ??? This info is likely going to be out of date very soon. */
|
||
CLEAR_REG_SET (bb->local_set);
|
||
if (old_succ->global_live_at_start)
|
||
{
|
||
COPY_REG_SET (bb->global_live_at_start, old_succ->global_live_at_start);
|
||
COPY_REG_SET (bb->global_live_at_end, old_succ->global_live_at_start);
|
||
}
|
||
else
|
||
{
|
||
CLEAR_REG_SET (bb->global_live_at_start);
|
||
CLEAR_REG_SET (bb->global_live_at_end);
|
||
}
|
||
|
||
/* Wire them up. */
|
||
bb->pred = edge_in;
|
||
bb->succ = edge_out;
|
||
|
||
edge_in->dest = bb;
|
||
edge_in->flags &= ~EDGE_CRITICAL;
|
||
|
||
edge_out->pred_next = old_succ->pred;
|
||
edge_out->succ_next = NULL;
|
||
edge_out->src = bb;
|
||
edge_out->dest = old_succ;
|
||
edge_out->flags = EDGE_FALLTHRU;
|
||
edge_out->probability = REG_BR_PROB_BASE;
|
||
|
||
old_succ->pred = edge_out;
|
||
|
||
/* Tricky case -- if there existed a fallthru into the successor
|
||
(and we're not it) we must add a new unconditional jump around
|
||
the new block we're actually interested in.
|
||
|
||
Further, if that edge is critical, this means a second new basic
|
||
block must be created to hold it. In order to simplify correct
|
||
insn placement, do this before we touch the existing basic block
|
||
ordering for the block we were really wanting. */
|
||
if ((edge_in->flags & EDGE_FALLTHRU) == 0)
|
||
{
|
||
edge e;
|
||
for (e = edge_out->pred_next; e ; e = e->pred_next)
|
||
if (e->flags & EDGE_FALLTHRU)
|
||
break;
|
||
|
||
if (e)
|
||
{
|
||
basic_block jump_block;
|
||
rtx pos;
|
||
|
||
if ((e->flags & EDGE_CRITICAL) == 0)
|
||
{
|
||
/* Non critical -- we can simply add a jump to the end
|
||
of the existing predecessor. */
|
||
jump_block = e->src;
|
||
}
|
||
else
|
||
{
|
||
/* We need a new block to hold the jump. The simplest
|
||
way to do the bulk of the work here is to recursively
|
||
call ourselves. */
|
||
jump_block = split_edge (e);
|
||
e = jump_block->succ;
|
||
}
|
||
|
||
/* Now add the jump insn ... */
|
||
pos = emit_jump_insn_after (gen_jump (old_succ->head),
|
||
jump_block->end);
|
||
jump_block->end = pos;
|
||
emit_barrier_after (pos);
|
||
|
||
/* ... let jump know that label is in use, ... */
|
||
++LABEL_NUSES (old_succ->head);
|
||
|
||
/* ... and clear fallthru on the outgoing edge. */
|
||
e->flags &= ~EDGE_FALLTHRU;
|
||
|
||
/* Continue splitting the interesting edge. */
|
||
}
|
||
}
|
||
|
||
/* Place the new block just in front of the successor. */
|
||
VARRAY_GROW (basic_block_info, ++n_basic_blocks);
|
||
for (i = n_basic_blocks - 1; i > old_succ->index; --i)
|
||
{
|
||
basic_block tmp = BASIC_BLOCK (i - 1);
|
||
BASIC_BLOCK (i) = tmp;
|
||
tmp->index = i;
|
||
}
|
||
BASIC_BLOCK (i) = bb;
|
||
bb->index = i;
|
||
|
||
/* Create the basic block note. */
|
||
bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, old_succ->head);
|
||
NOTE_BASIC_BLOCK (bb_note) = bb;
|
||
bb->head = bb->end = bb_note;
|
||
|
||
/* Not quite simple -- for non-fallthru edges, we must adjust the
|
||
predecessor's jump instruction to target our new block. */
|
||
if ((edge_in->flags & EDGE_FALLTHRU) == 0)
|
||
{
|
||
rtx tmp, insn = old_pred->end;
|
||
rtx old_label = old_succ->head;
|
||
rtx new_label = gen_label_rtx ();
|
||
|
||
if (GET_CODE (insn) != JUMP_INSN)
|
||
abort ();
|
||
|
||
/* ??? Recognize a tablejump and adjust all matching cases. */
|
||
if ((tmp = JUMP_LABEL (insn)) != NULL_RTX
|
||
&& (tmp = NEXT_INSN (tmp)) != NULL_RTX
|
||
&& GET_CODE (tmp) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (tmp)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
|
||
{
|
||
rtvec vec;
|
||
int j;
|
||
|
||
if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
|
||
vec = XVEC (PATTERN (tmp), 0);
|
||
else
|
||
vec = XVEC (PATTERN (tmp), 1);
|
||
|
||
for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j)
|
||
if (XEXP (RTVEC_ELT (vec, j), 0) == old_label)
|
||
{
|
||
RTVEC_ELT (vec, j) = gen_rtx_LABEL_REF (VOIDmode, new_label);
|
||
--LABEL_NUSES (old_label);
|
||
++LABEL_NUSES (new_label);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* This would have indicated an abnormal edge. */
|
||
if (computed_jump_p (insn))
|
||
abort ();
|
||
|
||
/* A return instruction can't be redirected. */
|
||
if (returnjump_p (insn))
|
||
abort ();
|
||
|
||
/* If the insn doesn't go where we think, we're confused. */
|
||
if (JUMP_LABEL (insn) != old_label)
|
||
abort ();
|
||
|
||
redirect_jump (insn, new_label);
|
||
}
|
||
|
||
emit_label_before (new_label, bb_note);
|
||
bb->head = new_label;
|
||
}
|
||
|
||
return bb;
|
||
}
|
||
|
||
/* Queue instructions for insertion on an edge between two basic blocks.
|
||
The new instructions and basic blocks (if any) will not appear in the
|
||
CFG until commit_edge_insertions is called. */
|
||
|
||
void
|
||
insert_insn_on_edge (pattern, e)
|
||
rtx pattern;
|
||
edge e;
|
||
{
|
||
/* We cannot insert instructions on an abnormal critical edge.
|
||
It will be easier to find the culprit if we die now. */
|
||
if ((e->flags & (EDGE_ABNORMAL|EDGE_CRITICAL))
|
||
== (EDGE_ABNORMAL|EDGE_CRITICAL))
|
||
abort ();
|
||
|
||
if (e->insns == NULL_RTX)
|
||
start_sequence ();
|
||
else
|
||
push_to_sequence (e->insns);
|
||
|
||
emit_insn (pattern);
|
||
|
||
e->insns = get_insns ();
|
||
end_sequence();
|
||
}
|
||
|
||
/* Update the CFG for the instructions queued on edge E. */
|
||
|
||
static void
|
||
commit_one_edge_insertion (e)
|
||
edge e;
|
||
{
|
||
rtx before = NULL_RTX, after = NULL_RTX, tmp;
|
||
basic_block bb;
|
||
|
||
/* Figure out where to put these things. If the destination has
|
||
one predecessor, insert there. Except for the exit block. */
|
||
if (e->dest->pred->pred_next == NULL
|
||
&& e->dest != EXIT_BLOCK_PTR)
|
||
{
|
||
bb = e->dest;
|
||
|
||
/* Get the location correct wrt a code label, and "nice" wrt
|
||
a basic block note, and before everything else. */
|
||
tmp = bb->head;
|
||
if (GET_CODE (tmp) == CODE_LABEL)
|
||
tmp = NEXT_INSN (tmp);
|
||
if (GET_CODE (tmp) == NOTE
|
||
&& NOTE_LINE_NUMBER (tmp) == NOTE_INSN_BASIC_BLOCK)
|
||
tmp = NEXT_INSN (tmp);
|
||
if (tmp == bb->head)
|
||
before = tmp;
|
||
else
|
||
after = PREV_INSN (tmp);
|
||
}
|
||
|
||
/* If the source has one successor and the edge is not abnormal,
|
||
insert there. Except for the entry block. */
|
||
else if ((e->flags & EDGE_ABNORMAL) == 0
|
||
&& e->src->succ->succ_next == NULL
|
||
&& e->src != ENTRY_BLOCK_PTR)
|
||
{
|
||
bb = e->src;
|
||
if (GET_CODE (bb->end) == JUMP_INSN)
|
||
{
|
||
/* ??? Is it possible to wind up with non-simple jumps? Perhaps
|
||
a jump with delay slots already filled? */
|
||
if (! simplejump_p (bb->end))
|
||
abort ();
|
||
|
||
before = bb->end;
|
||
}
|
||
else
|
||
{
|
||
/* We'd better be fallthru, or we've lost track of what's what. */
|
||
if ((e->flags & EDGE_FALLTHRU) == 0)
|
||
abort ();
|
||
|
||
after = bb->end;
|
||
}
|
||
}
|
||
|
||
/* Otherwise we must split the edge. */
|
||
else
|
||
{
|
||
bb = split_edge (e);
|
||
after = bb->end;
|
||
}
|
||
|
||
/* Now that we've found the spot, do the insertion. */
|
||
tmp = e->insns;
|
||
e->insns = NULL_RTX;
|
||
if (before)
|
||
{
|
||
emit_insns_before (tmp, before);
|
||
if (before == bb->head)
|
||
bb->head = before;
|
||
}
|
||
else
|
||
{
|
||
tmp = emit_insns_after (tmp, after);
|
||
if (after == bb->end)
|
||
bb->end = tmp;
|
||
}
|
||
}
|
||
|
||
/* Update the CFG for all queued instructions. */
|
||
|
||
void
|
||
commit_edge_insertions ()
|
||
{
|
||
int i;
|
||
basic_block bb;
|
||
|
||
i = -1;
|
||
bb = ENTRY_BLOCK_PTR;
|
||
while (1)
|
||
{
|
||
edge e, next;
|
||
|
||
for (e = bb->succ; e ; e = next)
|
||
{
|
||
next = e->succ_next;
|
||
if (e->insns)
|
||
commit_one_edge_insertion (e);
|
||
}
|
||
|
||
if (++i >= n_basic_blocks)
|
||
break;
|
||
bb = BASIC_BLOCK (i);
|
||
}
|
||
}
|
||
|
||
/* Delete all unreachable basic blocks. */
|
||
|
||
static void
|
||
delete_unreachable_blocks ()
|
||
{
|
||
basic_block *worklist, *tos;
|
||
int deleted_handler;
|
||
edge e;
|
||
int i, n;
|
||
|
||
n = n_basic_blocks;
|
||
tos = worklist = (basic_block *) alloca (sizeof (basic_block) * n);
|
||
|
||
/* Use basic_block->aux as a marker. Clear them all. */
|
||
|
||
for (i = 0; i < n; ++i)
|
||
BASIC_BLOCK (i)->aux = NULL;
|
||
|
||
/* Add our starting points to the worklist. Almost always there will
|
||
be only one. It isn't inconcievable that we might one day directly
|
||
support Fortran alternate entry points. */
|
||
|
||
for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
|
||
{
|
||
*tos++ = e->dest;
|
||
|
||
/* Mark the block with a handy non-null value. */
|
||
e->dest->aux = e;
|
||
}
|
||
|
||
/* Iterate: find everything reachable from what we've already seen. */
|
||
|
||
while (tos != worklist)
|
||
{
|
||
basic_block b = *--tos;
|
||
|
||
for (e = b->succ; e ; e = e->succ_next)
|
||
if (!e->dest->aux)
|
||
{
|
||
*tos++ = e->dest;
|
||
e->dest->aux = e;
|
||
}
|
||
}
|
||
|
||
/* Delete all unreachable basic blocks. Count down so that we don't
|
||
interfere with the block renumbering that happens in delete_block. */
|
||
|
||
deleted_handler = 0;
|
||
|
||
for (i = n - 1; i >= 0; --i)
|
||
{
|
||
basic_block b = BASIC_BLOCK (i);
|
||
|
||
if (b->aux != NULL)
|
||
/* This block was found. Tidy up the mark. */
|
||
b->aux = NULL;
|
||
else
|
||
deleted_handler |= delete_block (b);
|
||
}
|
||
|
||
/* Fix up edges that now fall through, or rather should now fall through
|
||
but previously required a jump around now deleted blocks. Simplify
|
||
the search by only examining blocks numerically adjacent, since this
|
||
is how find_basic_blocks created them. */
|
||
|
||
for (i = 1; i < n_basic_blocks; ++i)
|
||
{
|
||
basic_block b = BASIC_BLOCK (i - 1);
|
||
basic_block c = BASIC_BLOCK (i);
|
||
edge s;
|
||
|
||
/* We care about simple conditional or unconditional jumps with
|
||
a single successor.
|
||
|
||
If we had a conditional branch to the next instruction when
|
||
find_basic_blocks was called, then there will only be one
|
||
out edge for the block which ended with the conditional
|
||
branch (since we do not create duplicate edges).
|
||
|
||
Furthermore, the edge will be marked as a fallthru because we
|
||
merge the flags for the duplicate edges. So we do not want to
|
||
check that the edge is not a FALLTHRU edge. */
|
||
if ((s = b->succ) != NULL
|
||
&& s->succ_next == NULL
|
||
&& s->dest == c
|
||
/* If the last insn is not a normal conditional jump
|
||
(or an unconditional jump), then we can not tidy the
|
||
fallthru edge because we can not delete the jump. */
|
||
&& GET_CODE (b->end) == JUMP_INSN
|
||
&& condjump_p (b->end))
|
||
tidy_fallthru_edge (s, b, c);
|
||
}
|
||
|
||
/* Attempt to merge blocks as made possible by edge removal. If a block
|
||
has only one successor, and the successor has only one predecessor,
|
||
they may be combined. */
|
||
|
||
for (i = 0; i < n_basic_blocks; )
|
||
{
|
||
basic_block c, b = BASIC_BLOCK (i);
|
||
edge s;
|
||
|
||
/* A loop because chains of blocks might be combineable. */
|
||
while ((s = b->succ) != NULL
|
||
&& s->succ_next == NULL
|
||
&& (s->flags & EDGE_EH) == 0
|
||
&& (c = s->dest) != EXIT_BLOCK_PTR
|
||
&& c->pred->pred_next == NULL
|
||
/* If the last insn is not a normal conditional jump
|
||
(or an unconditional jump), then we can not merge
|
||
the blocks because we can not delete the jump. */
|
||
&& GET_CODE (b->end) == JUMP_INSN
|
||
&& condjump_p (b->end)
|
||
&& merge_blocks (s, b, c))
|
||
continue;
|
||
|
||
/* Don't get confused by the index shift caused by deleting blocks. */
|
||
i = b->index + 1;
|
||
}
|
||
|
||
/* If we deleted an exception handler, we may have EH region begin/end
|
||
blocks to remove as well. */
|
||
if (deleted_handler)
|
||
delete_eh_regions ();
|
||
}
|
||
|
||
/* Find EH regions for which there is no longer a handler, and delete them. */
|
||
|
||
static void
|
||
delete_eh_regions ()
|
||
{
|
||
rtx insn;
|
||
|
||
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
|
||
if (GET_CODE (insn) == NOTE)
|
||
{
|
||
if ((NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG) ||
|
||
(NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END))
|
||
{
|
||
int num = CODE_LABEL_NUMBER (insn);
|
||
/* A NULL handler indicates a region is no longer needed */
|
||
if (get_first_handler (num) == NULL)
|
||
{
|
||
NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
|
||
NOTE_SOURCE_FILE (insn) = 0;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Return true if NOTE is not one of the ones that must be kept paired,
|
||
so that we may simply delete them. */
|
||
|
||
static int
|
||
can_delete_note_p (note)
|
||
rtx note;
|
||
{
|
||
return (NOTE_LINE_NUMBER (note) == NOTE_INSN_DELETED
|
||
|| NOTE_LINE_NUMBER (note) == NOTE_INSN_BASIC_BLOCK);
|
||
}
|
||
|
||
/* Unlink a chain of insns between START and FINISH, leaving notes
|
||
that must be paired. */
|
||
|
||
static void
|
||
delete_insn_chain (start, finish)
|
||
rtx start, finish;
|
||
{
|
||
/* Unchain the insns one by one. It would be quicker to delete all
|
||
of these with a single unchaining, rather than one at a time, but
|
||
we need to keep the NOTE's. */
|
||
|
||
rtx next;
|
||
|
||
while (1)
|
||
{
|
||
next = NEXT_INSN (start);
|
||
if (GET_CODE (start) == NOTE && !can_delete_note_p (start))
|
||
;
|
||
else if (GET_CODE (start) == CODE_LABEL && !can_delete_label_p (start))
|
||
;
|
||
else
|
||
next = flow_delete_insn (start);
|
||
|
||
if (start == finish)
|
||
break;
|
||
start = next;
|
||
}
|
||
}
|
||
|
||
/* Delete the insns in a (non-live) block. We physically delete every
|
||
non-deleted-note insn, and update the flow graph appropriately.
|
||
|
||
Return nonzero if we deleted an exception handler. */
|
||
|
||
/* ??? Preserving all such notes strikes me as wrong. It would be nice
|
||
to post-process the stream to remove empty blocks, loops, ranges, etc. */
|
||
|
||
static int
|
||
delete_block (b)
|
||
basic_block b;
|
||
{
|
||
int deleted_handler = 0;
|
||
rtx insn, end, tmp;
|
||
|
||
/* If the head of this block is a CODE_LABEL, then it might be the
|
||
label for an exception handler which can't be reached.
|
||
|
||
We need to remove the label from the exception_handler_label list
|
||
and remove the associated NOTE_EH_REGION_BEG and NOTE_EH_REGION_END
|
||
notes. */
|
||
|
||
insn = b->head;
|
||
|
||
if (GET_CODE (insn) == CODE_LABEL)
|
||
{
|
||
rtx x, *prev = &exception_handler_labels;
|
||
|
||
for (x = exception_handler_labels; x; x = XEXP (x, 1))
|
||
{
|
||
if (XEXP (x, 0) == insn)
|
||
{
|
||
/* Found a match, splice this label out of the EH label list. */
|
||
*prev = XEXP (x, 1);
|
||
XEXP (x, 1) = NULL_RTX;
|
||
XEXP (x, 0) = NULL_RTX;
|
||
|
||
/* Remove the handler from all regions */
|
||
remove_handler (insn);
|
||
deleted_handler = 1;
|
||
break;
|
||
}
|
||
prev = &XEXP (x, 1);
|
||
}
|
||
|
||
/* This label may be referenced by code solely for its value, or
|
||
referenced by static data, or something. We have determined
|
||
that it is not reachable, but cannot delete the label itself.
|
||
Save code space and continue to delete the balance of the block,
|
||
along with properly updating the cfg. */
|
||
if (!can_delete_label_p (insn))
|
||
{
|
||
/* If we've only got one of these, skip the whole deleting
|
||
insns thing. */
|
||
if (insn == b->end)
|
||
goto no_delete_insns;
|
||
insn = NEXT_INSN (insn);
|
||
}
|
||
}
|
||
|
||
/* Include any jump table following the basic block. */
|
||
end = b->end;
|
||
if (GET_CODE (end) == JUMP_INSN
|
||
&& (tmp = JUMP_LABEL (end)) != NULL_RTX
|
||
&& (tmp = NEXT_INSN (tmp)) != NULL_RTX
|
||
&& GET_CODE (tmp) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (tmp)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC))
|
||
end = tmp;
|
||
|
||
/* Include any barrier that may follow the basic block. */
|
||
tmp = next_nonnote_insn (b->end);
|
||
if (tmp && GET_CODE (tmp) == BARRIER)
|
||
end = tmp;
|
||
|
||
delete_insn_chain (insn, end);
|
||
|
||
no_delete_insns:
|
||
|
||
/* Remove the edges into and out of this block. Note that there may
|
||
indeed be edges in, if we are removing an unreachable loop. */
|
||
{
|
||
edge e, next, *q;
|
||
|
||
for (e = b->pred; e ; e = next)
|
||
{
|
||
for (q = &e->src->succ; *q != e; q = &(*q)->succ_next)
|
||
continue;
|
||
*q = e->succ_next;
|
||
next = e->pred_next;
|
||
free (e);
|
||
}
|
||
for (e = b->succ; e ; e = next)
|
||
{
|
||
for (q = &e->dest->pred; *q != e; q = &(*q)->pred_next)
|
||
continue;
|
||
*q = e->pred_next;
|
||
next = e->succ_next;
|
||
free (e);
|
||
}
|
||
|
||
b->pred = NULL;
|
||
b->succ = NULL;
|
||
}
|
||
|
||
/* Remove the basic block from the array, and compact behind it. */
|
||
expunge_block (b);
|
||
|
||
return deleted_handler;
|
||
}
|
||
|
||
/* Remove block B from the basic block array and compact behind it. */
|
||
|
||
static void
|
||
expunge_block (b)
|
||
basic_block b;
|
||
{
|
||
int i, n = n_basic_blocks;
|
||
|
||
for (i = b->index; i + 1 < n; ++i)
|
||
{
|
||
basic_block x = BASIC_BLOCK (i + 1);
|
||
BASIC_BLOCK (i) = x;
|
||
x->index = i;
|
||
}
|
||
|
||
basic_block_info->num_elements--;
|
||
n_basic_blocks--;
|
||
}
|
||
|
||
/* Delete INSN by patching it out. Return the next insn. */
|
||
|
||
static rtx
|
||
flow_delete_insn (insn)
|
||
rtx insn;
|
||
{
|
||
rtx prev = PREV_INSN (insn);
|
||
rtx next = NEXT_INSN (insn);
|
||
rtx note;
|
||
|
||
PREV_INSN (insn) = NULL_RTX;
|
||
NEXT_INSN (insn) = NULL_RTX;
|
||
|
||
if (prev)
|
||
NEXT_INSN (prev) = next;
|
||
if (next)
|
||
PREV_INSN (next) = prev;
|
||
else
|
||
set_last_insn (prev);
|
||
|
||
if (GET_CODE (insn) == CODE_LABEL)
|
||
remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
|
||
|
||
/* If deleting a jump, decrement the use count of the label. Deleting
|
||
the label itself should happen in the normal course of block merging. */
|
||
if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
|
||
LABEL_NUSES (JUMP_LABEL (insn))--;
|
||
|
||
/* Also if deleting an insn that references a label. */
|
||
else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX)
|
||
LABEL_NUSES (XEXP (note, 0))--;
|
||
|
||
return next;
|
||
}
|
||
|
||
/* True if a given label can be deleted. */
|
||
|
||
static int
|
||
can_delete_label_p (label)
|
||
rtx label;
|
||
{
|
||
rtx x;
|
||
|
||
if (LABEL_PRESERVE_P (label))
|
||
return 0;
|
||
|
||
for (x = forced_labels; x ; x = XEXP (x, 1))
|
||
if (label == XEXP (x, 0))
|
||
return 0;
|
||
for (x = label_value_list; x ; x = XEXP (x, 1))
|
||
if (label == XEXP (x, 0))
|
||
return 0;
|
||
for (x = exception_handler_labels; x ; x = XEXP (x, 1))
|
||
if (label == XEXP (x, 0))
|
||
return 0;
|
||
|
||
/* User declared labels must be preserved. */
|
||
if (LABEL_NAME (label) != 0)
|
||
return 0;
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Blocks A and B are to be merged into a single block. The insns
|
||
are already contiguous, hence `nomove'. */
|
||
|
||
static void
|
||
merge_blocks_nomove (a, b)
|
||
basic_block a, b;
|
||
{
|
||
edge e;
|
||
rtx b_head, b_end, a_end;
|
||
int b_empty = 0;
|
||
|
||
/* If there was a CODE_LABEL beginning B, delete it. */
|
||
b_head = b->head;
|
||
b_end = b->end;
|
||
if (GET_CODE (b_head) == CODE_LABEL)
|
||
{
|
||
/* Detect basic blocks with nothing but a label. This can happen
|
||
in particular at the end of a function. */
|
||
if (b_head == b_end)
|
||
b_empty = 1;
|
||
b_head = flow_delete_insn (b_head);
|
||
}
|
||
|
||
/* Delete the basic block note. */
|
||
if (GET_CODE (b_head) == NOTE
|
||
&& NOTE_LINE_NUMBER (b_head) == NOTE_INSN_BASIC_BLOCK)
|
||
{
|
||
if (b_head == b_end)
|
||
b_empty = 1;
|
||
b_head = flow_delete_insn (b_head);
|
||
}
|
||
|
||
/* If there was a jump out of A, delete it. */
|
||
a_end = a->end;
|
||
if (GET_CODE (a_end) == JUMP_INSN)
|
||
{
|
||
rtx prev;
|
||
|
||
prev = prev_nonnote_insn (a_end);
|
||
if (!prev)
|
||
prev = a->head;
|
||
|
||
#ifdef HAVE_cc0
|
||
/* If this was a conditional jump, we need to also delete
|
||
the insn that set cc0. */
|
||
|
||
if (prev && sets_cc0_p (prev))
|
||
{
|
||
rtx tmp = prev;
|
||
prev = prev_nonnote_insn (prev);
|
||
if (!prev)
|
||
prev = a->head;
|
||
flow_delete_insn (tmp);
|
||
}
|
||
#endif
|
||
|
||
/* Note that a->head != a->end, since we should have at least a
|
||
bb note plus the jump, so prev != insn. */
|
||
flow_delete_insn (a_end);
|
||
a_end = prev;
|
||
}
|
||
|
||
/* By definition, there should only be one successor of A, and that is
|
||
B. Free that edge struct. */
|
||
free (a->succ);
|
||
|
||
/* Adjust the edges out of B for the new owner. */
|
||
for (e = b->succ; e ; e = e->succ_next)
|
||
e->src = a;
|
||
a->succ = b->succ;
|
||
|
||
/* Reassociate the insns of B with A. */
|
||
if (!b_empty)
|
||
{
|
||
BLOCK_FOR_INSN (b_head) = a;
|
||
while (b_head != b_end)
|
||
{
|
||
b_head = NEXT_INSN (b_head);
|
||
BLOCK_FOR_INSN (b_head) = a;
|
||
}
|
||
a_end = b_head;
|
||
}
|
||
a->end = a_end;
|
||
|
||
/* Compact the basic block array. */
|
||
expunge_block (b);
|
||
}
|
||
|
||
/* Attempt to merge basic blocks that are potentially non-adjacent.
|
||
Return true iff the attempt succeeded. */
|
||
|
||
static int
|
||
merge_blocks (e, b, c)
|
||
edge e;
|
||
basic_block b, c;
|
||
{
|
||
/* If B has a fallthru edge to C, no need to move anything. */
|
||
if (!(e->flags & EDGE_FALLTHRU))
|
||
{
|
||
/* ??? From here on out we must make sure to not munge nesting
|
||
of exception regions and lexical blocks. Need to think about
|
||
these cases before this gets implemented. */
|
||
return 0;
|
||
|
||
/* If C has an outgoing fallthru, and B does not have an incoming
|
||
fallthru, move B before C. The later clause is somewhat arbitrary,
|
||
but avoids modifying blocks other than the two we've been given. */
|
||
|
||
/* Otherwise, move C after B. If C had a fallthru, which doesn't
|
||
happen to be the physical successor to B, insert an unconditional
|
||
branch. If C already ended with a conditional branch, the new
|
||
jump must go in a new basic block D. */
|
||
}
|
||
|
||
/* If a label still appears somewhere and we cannot delete the label,
|
||
then we cannot merge the blocks. The edge was tidied already. */
|
||
{
|
||
rtx insn, stop = NEXT_INSN (c->head);
|
||
for (insn = NEXT_INSN (b->end); insn != stop; insn = NEXT_INSN (insn))
|
||
if (GET_CODE (insn) == CODE_LABEL && !can_delete_label_p (insn))
|
||
return 0;
|
||
}
|
||
|
||
merge_blocks_nomove (b, c);
|
||
return 1;
|
||
}
|
||
|
||
/* The given edge should potentially a fallthru edge. If that is in
|
||
fact true, delete the unconditional jump and barriers that are in
|
||
the way. */
|
||
|
||
static void
|
||
tidy_fallthru_edge (e, b, c)
|
||
edge e;
|
||
basic_block b, c;
|
||
{
|
||
rtx q;
|
||
|
||
/* ??? In a late-running flow pass, other folks may have deleted basic
|
||
blocks by nopping out blocks, leaving multiple BARRIERs between here
|
||
and the target label. They ought to be chastized and fixed.
|
||
|
||
We can also wind up with a sequence of undeletable labels between
|
||
one block and the next.
|
||
|
||
So search through a sequence of barriers, labels, and notes for
|
||
the head of block C and assert that we really do fall through. */
|
||
|
||
if (next_real_insn (b->end) != next_real_insn (PREV_INSN (c->head)))
|
||
return;
|
||
|
||
/* Remove what will soon cease being the jump insn from the source block.
|
||
If block B consisted only of this single jump, turn it into a deleted
|
||
note. */
|
||
q = b->end;
|
||
if (GET_CODE (q) == JUMP_INSN)
|
||
{
|
||
#ifdef HAVE_cc0
|
||
/* If this was a conditional jump, we need to also delete
|
||
the insn that set cc0. */
|
||
if (! simplejump_p (q) && condjump_p (q))
|
||
q = PREV_INSN (q);
|
||
#endif
|
||
|
||
if (b->head == q)
|
||
{
|
||
PUT_CODE (q, NOTE);
|
||
NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED;
|
||
NOTE_SOURCE_FILE (q) = 0;
|
||
}
|
||
else
|
||
b->end = q = PREV_INSN (q);
|
||
}
|
||
|
||
/* Selectively unlink the sequence. */
|
||
if (q != PREV_INSN (c->head))
|
||
delete_insn_chain (NEXT_INSN (q), PREV_INSN (c->head));
|
||
|
||
e->flags |= EDGE_FALLTHRU;
|
||
}
|
||
|
||
/* Discover and record the loop depth at the head of each basic block. */
|
||
|
||
static void
|
||
calculate_loop_depth (insns)
|
||
rtx insns;
|
||
{
|
||
basic_block bb;
|
||
rtx insn;
|
||
int i = 0, depth = 1;
|
||
|
||
bb = BASIC_BLOCK (i);
|
||
for (insn = insns; insn ; insn = NEXT_INSN (insn))
|
||
{
|
||
if (insn == bb->head)
|
||
{
|
||
bb->loop_depth = depth;
|
||
if (++i >= n_basic_blocks)
|
||
break;
|
||
bb = BASIC_BLOCK (i);
|
||
}
|
||
|
||
if (GET_CODE (insn) == NOTE)
|
||
{
|
||
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
|
||
depth++;
|
||
else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
|
||
depth--;
|
||
|
||
/* If we have LOOP_DEPTH == 0, there has been a bookkeeping error. */
|
||
if (depth == 0)
|
||
abort ();
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Perform data flow analysis.
|
||
F is the first insn of the function and NREGS the number of register numbers
|
||
in use. */
|
||
|
||
void
|
||
life_analysis (f, nregs, file, remove_dead_code)
|
||
rtx f;
|
||
int nregs;
|
||
FILE *file;
|
||
int remove_dead_code;
|
||
{
|
||
#ifdef ELIMINABLE_REGS
|
||
register size_t i;
|
||
static struct {int from, to; } eliminables[] = ELIMINABLE_REGS;
|
||
#endif
|
||
|
||
/* Record which registers will be eliminated. We use this in
|
||
mark_used_regs. */
|
||
|
||
CLEAR_HARD_REG_SET (elim_reg_set);
|
||
|
||
#ifdef ELIMINABLE_REGS
|
||
for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++)
|
||
SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
|
||
#else
|
||
SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
|
||
#endif
|
||
|
||
/* Allocate a bitmap to be filled in by record_volatile_insns. */
|
||
uid_volatile = BITMAP_ALLOCA ();
|
||
|
||
/* We want alias analysis information for local dead store elimination. */
|
||
init_alias_analysis ();
|
||
life_analysis_1 (f, nregs, remove_dead_code);
|
||
end_alias_analysis ();
|
||
|
||
if (file)
|
||
dump_flow_info (file);
|
||
|
||
BITMAP_FREE (uid_volatile);
|
||
free_basic_block_vars (1);
|
||
}
|
||
|
||
/* Free the variables allocated by find_basic_blocks.
|
||
|
||
KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
|
||
|
||
void
|
||
free_basic_block_vars (keep_head_end_p)
|
||
int keep_head_end_p;
|
||
{
|
||
if (basic_block_for_insn)
|
||
{
|
||
VARRAY_FREE (basic_block_for_insn);
|
||
basic_block_for_insn = NULL;
|
||
}
|
||
|
||
if (! keep_head_end_p)
|
||
{
|
||
clear_edges ();
|
||
VARRAY_FREE (basic_block_info);
|
||
n_basic_blocks = 0;
|
||
|
||
ENTRY_BLOCK_PTR->aux = NULL;
|
||
ENTRY_BLOCK_PTR->global_live_at_end = NULL;
|
||
EXIT_BLOCK_PTR->aux = NULL;
|
||
EXIT_BLOCK_PTR->global_live_at_start = NULL;
|
||
}
|
||
}
|
||
|
||
/* Return nonzero if the destination of SET equals the source. */
|
||
static int
|
||
set_noop_p (set)
|
||
rtx set;
|
||
{
|
||
rtx src = SET_SRC (set);
|
||
rtx dst = SET_DEST (set);
|
||
if (GET_CODE (src) == REG && GET_CODE (dst) == REG
|
||
&& REGNO (src) == REGNO (dst))
|
||
return 1;
|
||
if (GET_CODE (src) != SUBREG || GET_CODE (dst) != SUBREG
|
||
|| SUBREG_WORD (src) != SUBREG_WORD (dst))
|
||
return 0;
|
||
src = SUBREG_REG (src);
|
||
dst = SUBREG_REG (dst);
|
||
if (GET_CODE (src) == REG && GET_CODE (dst) == REG
|
||
&& REGNO (src) == REGNO (dst))
|
||
return 1;
|
||
return 0;
|
||
}
|
||
|
||
/* Return nonzero if an insn consists only of SETs, each of which only sets a
|
||
value to itself. */
|
||
static int
|
||
noop_move_p (insn)
|
||
rtx insn;
|
||
{
|
||
rtx pat = PATTERN (insn);
|
||
|
||
/* Insns carrying these notes are useful later on. */
|
||
if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
|
||
return 0;
|
||
|
||
if (GET_CODE (pat) == SET && set_noop_p (pat))
|
||
return 1;
|
||
|
||
if (GET_CODE (pat) == PARALLEL)
|
||
{
|
||
int i;
|
||
/* If nothing but SETs of registers to themselves,
|
||
this insn can also be deleted. */
|
||
for (i = 0; i < XVECLEN (pat, 0); i++)
|
||
{
|
||
rtx tem = XVECEXP (pat, 0, i);
|
||
|
||
if (GET_CODE (tem) == USE
|
||
|| GET_CODE (tem) == CLOBBER)
|
||
continue;
|
||
|
||
if (GET_CODE (tem) != SET || ! set_noop_p (tem))
|
||
return 0;
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
notice_stack_pointer_modification (x, pat)
|
||
rtx x;
|
||
rtx pat ATTRIBUTE_UNUSED;
|
||
{
|
||
if (x == stack_pointer_rtx
|
||
/* The stack pointer is only modified indirectly as the result
|
||
of a push until later in flow. See the comments in rtl.texi
|
||
regarding Embedded Side-Effects on Addresses. */
|
||
|| (GET_CODE (x) == MEM
|
||
&& (GET_CODE (XEXP (x, 0)) == PRE_DEC
|
||
|| GET_CODE (XEXP (x, 0)) == PRE_INC
|
||
|| GET_CODE (XEXP (x, 0)) == POST_DEC
|
||
|| GET_CODE (XEXP (x, 0)) == POST_INC)
|
||
&& XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
|
||
current_function_sp_is_unchanging = 0;
|
||
}
|
||
|
||
/* Record which insns refer to any volatile memory
|
||
or for any reason can't be deleted just because they are dead stores.
|
||
Also, delete any insns that copy a register to itself.
|
||
And see if the stack pointer is modified. */
|
||
static void
|
||
record_volatile_insns (f)
|
||
rtx f;
|
||
{
|
||
rtx insn;
|
||
for (insn = f; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
enum rtx_code code1 = GET_CODE (insn);
|
||
if (code1 == CALL_INSN)
|
||
SET_INSN_VOLATILE (insn);
|
||
else if (code1 == INSN || code1 == JUMP_INSN)
|
||
{
|
||
if (GET_CODE (PATTERN (insn)) != USE
|
||
&& volatile_refs_p (PATTERN (insn)))
|
||
SET_INSN_VOLATILE (insn);
|
||
|
||
/* A SET that makes space on the stack cannot be dead.
|
||
(Such SETs occur only for allocating variable-size data,
|
||
so they will always have a PLUS or MINUS according to the
|
||
direction of stack growth.)
|
||
Even if this function never uses this stack pointer value,
|
||
signal handlers do! */
|
||
else if (code1 == INSN && GET_CODE (PATTERN (insn)) == SET
|
||
&& SET_DEST (PATTERN (insn)) == stack_pointer_rtx
|
||
#ifdef STACK_GROWS_DOWNWARD
|
||
&& GET_CODE (SET_SRC (PATTERN (insn))) == MINUS
|
||
#else
|
||
&& GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
|
||
#endif
|
||
&& XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx)
|
||
SET_INSN_VOLATILE (insn);
|
||
|
||
/* Delete (in effect) any obvious no-op moves. */
|
||
else if (noop_move_p (insn))
|
||
{
|
||
PUT_CODE (insn, NOTE);
|
||
NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
|
||
NOTE_SOURCE_FILE (insn) = 0;
|
||
}
|
||
}
|
||
|
||
/* Check if insn modifies the stack pointer. */
|
||
if ( current_function_sp_is_unchanging
|
||
&& GET_RTX_CLASS (GET_CODE (insn)) == 'i')
|
||
note_stores (PATTERN (insn), notice_stack_pointer_modification);
|
||
}
|
||
}
|
||
|
||
/* Mark those regs which are needed at the end of the function as live
|
||
at the end of the last basic block. */
|
||
static void
|
||
mark_regs_live_at_end (set)
|
||
regset set;
|
||
{
|
||
int i;
|
||
|
||
/* If exiting needs the right stack value, consider the stack pointer
|
||
live at the end of the function. */
|
||
if (! EXIT_IGNORE_STACK
|
||
|| (! FRAME_POINTER_REQUIRED
|
||
&& ! current_function_calls_alloca
|
||
&& flag_omit_frame_pointer)
|
||
|| current_function_sp_is_unchanging)
|
||
{
|
||
SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
|
||
}
|
||
|
||
/* Mark the frame pointer if needed at the end of the function. If
|
||
we end up eliminating it, it will be removed from the live list
|
||
of each basic block by reload. */
|
||
|
||
if (! reload_completed || frame_pointer_needed)
|
||
{
|
||
SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
|
||
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
|
||
/* If they are different, also mark the hard frame pointer as live */
|
||
SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
|
||
#endif
|
||
}
|
||
|
||
/* Mark all global registers, and all registers used by the epilogue
|
||
as being live at the end of the function since they may be
|
||
referenced by our caller. */
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (global_regs[i]
|
||
#ifdef EPILOGUE_USES
|
||
|| EPILOGUE_USES (i)
|
||
#endif
|
||
)
|
||
SET_REGNO_REG_SET (set, i);
|
||
|
||
/* ??? Mark function return value here rather than as uses. */
|
||
}
|
||
|
||
/* Determine which registers are live at the start of each
|
||
basic block of the function whose first insn is F.
|
||
NREGS is the number of registers used in F.
|
||
We allocate the vector basic_block_live_at_start
|
||
and the regsets that it points to, and fill them with the data.
|
||
regset_size and regset_bytes are also set here. */
|
||
|
||
static void
|
||
life_analysis_1 (f, nregs, remove_dead_code)
|
||
rtx f;
|
||
int nregs;
|
||
int remove_dead_code;
|
||
{
|
||
int first_pass;
|
||
int changed;
|
||
register int i;
|
||
char save_regs_ever_live[FIRST_PSEUDO_REGISTER];
|
||
regset *new_live_at_end;
|
||
|
||
struct obstack flow_obstack;
|
||
|
||
gcc_obstack_init (&flow_obstack);
|
||
|
||
max_regno = nregs;
|
||
|
||
/* Allocate and zero out many data structures
|
||
that will record the data from lifetime analysis. */
|
||
|
||
allocate_reg_life_data ();
|
||
allocate_bb_life_data ();
|
||
|
||
reg_next_use = (rtx *) alloca (nregs * sizeof (rtx));
|
||
memset (reg_next_use, 0, nregs * sizeof (rtx));
|
||
|
||
/* Set up regset-vectors used internally within this function.
|
||
Their meanings are documented above, with their declarations. */
|
||
|
||
new_live_at_end = (regset *) alloca ((n_basic_blocks + 1) * sizeof (regset));
|
||
init_regset_vector (new_live_at_end, n_basic_blocks + 1, &flow_obstack);
|
||
|
||
/* Stick these vectors into the AUX field of the basic block, so that
|
||
we don't have to keep going through the index. */
|
||
|
||
for (i = 0; i < n_basic_blocks; ++i)
|
||
BASIC_BLOCK (i)->aux = new_live_at_end[i];
|
||
ENTRY_BLOCK_PTR->aux = new_live_at_end[i];
|
||
|
||
/* Assume that the stack pointer is unchanging if alloca hasn't been used.
|
||
This will be cleared by record_volatile_insns if it encounters an insn
|
||
which modifies the stack pointer. */
|
||
current_function_sp_is_unchanging = !current_function_calls_alloca;
|
||
|
||
record_volatile_insns (f);
|
||
|
||
if (n_basic_blocks > 0)
|
||
{
|
||
regset theend;
|
||
register edge e;
|
||
|
||
theend = EXIT_BLOCK_PTR->global_live_at_start;
|
||
mark_regs_live_at_end (theend);
|
||
|
||
/* Propogate this exit data to each of EXIT's predecessors. */
|
||
for (e = EXIT_BLOCK_PTR->pred; e ; e = e->pred_next)
|
||
{
|
||
COPY_REG_SET (e->src->global_live_at_end, theend);
|
||
COPY_REG_SET ((regset) e->src->aux, theend);
|
||
}
|
||
}
|
||
|
||
/* The post-reload life analysis have (on a global basis) the same registers
|
||
live as was computed by reload itself.
|
||
|
||
Otherwise elimination offsets and such may be incorrect.
|
||
|
||
Reload will make some registers as live even though they do not appear
|
||
in the rtl. */
|
||
if (reload_completed)
|
||
memcpy (save_regs_ever_live, regs_ever_live, sizeof (regs_ever_live));
|
||
memset (regs_ever_live, 0, sizeof regs_ever_live);
|
||
|
||
/* Propagate life info through the basic blocks
|
||
around the graph of basic blocks.
|
||
|
||
This is a relaxation process: each time a new register
|
||
is live at the end of the basic block, we must scan the block
|
||
to determine which registers are, as a consequence, live at the beginning
|
||
of that block. These registers must then be marked live at the ends
|
||
of all the blocks that can transfer control to that block.
|
||
The process continues until it reaches a fixed point. */
|
||
|
||
first_pass = 1;
|
||
changed = 1;
|
||
while (changed)
|
||
{
|
||
changed = 0;
|
||
for (i = n_basic_blocks - 1; i >= 0; i--)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
int consider = first_pass;
|
||
int must_rescan = first_pass;
|
||
register int j;
|
||
|
||
if (!first_pass)
|
||
{
|
||
/* Set CONSIDER if this block needs thinking about at all
|
||
(that is, if the regs live now at the end of it
|
||
are not the same as were live at the end of it when
|
||
we last thought about it).
|
||
Set must_rescan if it needs to be thought about
|
||
instruction by instruction (that is, if any additional
|
||
reg that is live at the end now but was not live there before
|
||
is one of the significant regs of this basic block). */
|
||
|
||
EXECUTE_IF_AND_COMPL_IN_REG_SET
|
||
((regset) bb->aux, bb->global_live_at_end, 0, j,
|
||
{
|
||
consider = 1;
|
||
if (REGNO_REG_SET_P (bb->local_set, j))
|
||
{
|
||
must_rescan = 1;
|
||
goto done;
|
||
}
|
||
});
|
||
done:
|
||
if (! consider)
|
||
continue;
|
||
}
|
||
|
||
/* The live_at_start of this block may be changing,
|
||
so another pass will be required after this one. */
|
||
changed = 1;
|
||
|
||
if (! must_rescan)
|
||
{
|
||
/* No complete rescan needed;
|
||
just record those variables newly known live at end
|
||
as live at start as well. */
|
||
IOR_AND_COMPL_REG_SET (bb->global_live_at_start,
|
||
(regset) bb->aux,
|
||
bb->global_live_at_end);
|
||
|
||
IOR_AND_COMPL_REG_SET (bb->global_live_at_end,
|
||
(regset) bb->aux,
|
||
bb->global_live_at_end);
|
||
}
|
||
else
|
||
{
|
||
/* Update the basic_block_live_at_start
|
||
by propagation backwards through the block. */
|
||
COPY_REG_SET (bb->global_live_at_end, (regset) bb->aux);
|
||
COPY_REG_SET (bb->global_live_at_start,
|
||
bb->global_live_at_end);
|
||
propagate_block (bb->global_live_at_start,
|
||
bb->head, bb->end, 0,
|
||
first_pass ? bb->local_set : (regset) 0,
|
||
i, remove_dead_code);
|
||
}
|
||
|
||
/* Update the new_live_at_end's of the block's predecessors. */
|
||
{
|
||
register edge e;
|
||
|
||
for (e = bb->pred; e ; e = e->pred_next)
|
||
IOR_REG_SET ((regset) e->src->aux, bb->global_live_at_start);
|
||
}
|
||
|
||
#ifdef USE_C_ALLOCA
|
||
alloca (0);
|
||
#endif
|
||
}
|
||
first_pass = 0;
|
||
}
|
||
|
||
/* The only pseudos that are live at the beginning of the function are
|
||
those that were not set anywhere in the function. local-alloc doesn't
|
||
know how to handle these correctly, so mark them as not local to any
|
||
one basic block. */
|
||
|
||
if (n_basic_blocks > 0)
|
||
EXECUTE_IF_SET_IN_REG_SET (BASIC_BLOCK (0)->global_live_at_start,
|
||
FIRST_PSEUDO_REGISTER, i,
|
||
{
|
||
REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
|
||
});
|
||
|
||
/* Now the life information is accurate. Make one more pass over each
|
||
basic block to delete dead stores, create autoincrement addressing
|
||
and record how many times each register is used, is set, or dies. */
|
||
|
||
for (i = 0; i < n_basic_blocks; i++)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
/* We start with global_live_at_end to determine which stores are
|
||
dead. This process is destructive, and we wish to preserve the
|
||
contents of global_live_at_end for posterity. Fortunately,
|
||
new_live_at_end, due to the way we converged on a solution,
|
||
contains a duplicate of global_live_at_end that we can kill. */
|
||
propagate_block ((regset) bb->aux, bb->head, bb->end, 1, (regset) 0, i, remove_dead_code);
|
||
|
||
#ifdef USE_C_ALLOCA
|
||
alloca (0);
|
||
#endif
|
||
}
|
||
|
||
/* We have a problem with any pseudoreg that lives across the setjmp.
|
||
ANSI says that if a user variable does not change in value between
|
||
the setjmp and the longjmp, then the longjmp preserves it. This
|
||
includes longjmp from a place where the pseudo appears dead.
|
||
(In principle, the value still exists if it is in scope.)
|
||
If the pseudo goes in a hard reg, some other value may occupy
|
||
that hard reg where this pseudo is dead, thus clobbering the pseudo.
|
||
Conclusion: such a pseudo must not go in a hard reg. */
|
||
EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
|
||
FIRST_PSEUDO_REGISTER, i,
|
||
{
|
||
if (regno_reg_rtx[i] != 0)
|
||
{
|
||
REG_LIVE_LENGTH (i) = -1;
|
||
REG_BASIC_BLOCK (i) = -1;
|
||
}
|
||
});
|
||
|
||
/* Restore regs_ever_live that was provided by reload. */
|
||
if (reload_completed)
|
||
memcpy (regs_ever_live, save_regs_ever_live, sizeof (regs_ever_live));
|
||
|
||
free_regset_vector (new_live_at_end, n_basic_blocks);
|
||
obstack_free (&flow_obstack, NULL_PTR);
|
||
|
||
for (i = 0; i < n_basic_blocks; ++i)
|
||
BASIC_BLOCK (i)->aux = NULL;
|
||
ENTRY_BLOCK_PTR->aux = NULL;
|
||
}
|
||
|
||
/* Subroutines of life analysis. */
|
||
|
||
/* Allocate the permanent data structures that represent the results
|
||
of life analysis. Not static since used also for stupid life analysis. */
|
||
|
||
void
|
||
allocate_bb_life_data ()
|
||
{
|
||
register int i;
|
||
|
||
for (i = 0; i < n_basic_blocks; i++)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
bb->local_set = OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
}
|
||
|
||
ENTRY_BLOCK_PTR->global_live_at_end
|
||
= OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
EXIT_BLOCK_PTR->global_live_at_start
|
||
= OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
|
||
regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (function_obstack);
|
||
}
|
||
|
||
void
|
||
allocate_reg_life_data ()
|
||
{
|
||
int i;
|
||
|
||
/* Recalculate the register space, in case it has grown. Old style
|
||
vector oriented regsets would set regset_{size,bytes} here also. */
|
||
allocate_reg_info (max_regno, FALSE, FALSE);
|
||
|
||
/* Because both reg_scan and flow_analysis want to set up the REG_N_SETS
|
||
information, explicitly reset it here. The allocation should have
|
||
already happened on the previous reg_scan pass. Make sure in case
|
||
some more registers were allocated. */
|
||
for (i = 0; i < max_regno; i++)
|
||
REG_N_SETS (i) = 0;
|
||
}
|
||
|
||
/* Make each element of VECTOR point at a regset. The vector has
|
||
NELTS elements, and space is allocated from the ALLOC_OBSTACK
|
||
obstack. */
|
||
|
||
static void
|
||
init_regset_vector (vector, nelts, alloc_obstack)
|
||
regset *vector;
|
||
int nelts;
|
||
struct obstack *alloc_obstack;
|
||
{
|
||
register int i;
|
||
|
||
for (i = 0; i < nelts; i++)
|
||
{
|
||
vector[i] = OBSTACK_ALLOC_REG_SET (alloc_obstack);
|
||
CLEAR_REG_SET (vector[i]);
|
||
}
|
||
}
|
||
|
||
/* Release any additional space allocated for each element of VECTOR point
|
||
other than the regset header itself. The vector has NELTS elements. */
|
||
|
||
void
|
||
free_regset_vector (vector, nelts)
|
||
regset *vector;
|
||
int nelts;
|
||
{
|
||
register int i;
|
||
|
||
for (i = 0; i < nelts; i++)
|
||
FREE_REG_SET (vector[i]);
|
||
}
|
||
|
||
/* Compute the registers live at the beginning of a basic block
|
||
from those live at the end.
|
||
|
||
When called, OLD contains those live at the end.
|
||
On return, it contains those live at the beginning.
|
||
FIRST and LAST are the first and last insns of the basic block.
|
||
|
||
FINAL is nonzero if we are doing the final pass which is not
|
||
for computing the life info (since that has already been done)
|
||
but for acting on it. On this pass, we delete dead stores,
|
||
set up the logical links and dead-variables lists of instructions,
|
||
and merge instructions for autoincrement and autodecrement addresses.
|
||
|
||
SIGNIFICANT is nonzero only the first time for each basic block.
|
||
If it is nonzero, it points to a regset in which we store
|
||
a 1 for each register that is set within the block.
|
||
|
||
BNUM is the number of the basic block. */
|
||
|
||
static void
|
||
propagate_block (old, first, last, final, significant, bnum, remove_dead_code)
|
||
register regset old;
|
||
rtx first;
|
||
rtx last;
|
||
int final;
|
||
regset significant;
|
||
int bnum;
|
||
int remove_dead_code;
|
||
{
|
||
register rtx insn;
|
||
rtx prev;
|
||
regset live;
|
||
regset dead;
|
||
|
||
/* Find the loop depth for this block. Ignore loop level changes in the
|
||
middle of the basic block -- for register allocation purposes, the
|
||
important uses will be in the blocks wholely contained within the loop
|
||
not in the loop pre-header or post-trailer. */
|
||
loop_depth = BASIC_BLOCK (bnum)->loop_depth;
|
||
|
||
dead = ALLOCA_REG_SET ();
|
||
live = ALLOCA_REG_SET ();
|
||
|
||
cc0_live = 0;
|
||
mem_set_list = NULL_RTX;
|
||
|
||
if (final)
|
||
{
|
||
register int i;
|
||
|
||
/* Process the regs live at the end of the block.
|
||
Mark them as not local to any one basic block. */
|
||
EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
|
||
{
|
||
REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL;
|
||
});
|
||
}
|
||
|
||
/* Scan the block an insn at a time from end to beginning. */
|
||
|
||
for (insn = last; ; insn = prev)
|
||
{
|
||
prev = PREV_INSN (insn);
|
||
|
||
if (GET_CODE (insn) == NOTE)
|
||
{
|
||
/* If this is a call to `setjmp' et al,
|
||
warn if any non-volatile datum is live. */
|
||
|
||
if (final && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP)
|
||
IOR_REG_SET (regs_live_at_setjmp, old);
|
||
}
|
||
|
||
/* Update the life-status of regs for this insn.
|
||
First DEAD gets which regs are set in this insn
|
||
then LIVE gets which regs are used in this insn.
|
||
Then the regs live before the insn
|
||
are those live after, with DEAD regs turned off,
|
||
and then LIVE regs turned on. */
|
||
|
||
else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
|
||
{
|
||
register int i;
|
||
rtx note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
|
||
int insn_is_dead = 0;
|
||
int libcall_is_dead = 0;
|
||
|
||
if (remove_dead_code)
|
||
{
|
||
insn_is_dead = (insn_dead_p (PATTERN (insn), old, 0, REG_NOTES (insn))
|
||
/* Don't delete something that refers to volatile storage! */
|
||
&& ! INSN_VOLATILE (insn));
|
||
libcall_is_dead = (insn_is_dead && note != 0
|
||
&& libcall_dead_p (PATTERN (insn), old, note, insn));
|
||
}
|
||
|
||
/* If an instruction consists of just dead store(s) on final pass,
|
||
"delete" it by turning it into a NOTE of type NOTE_INSN_DELETED.
|
||
We could really delete it with delete_insn, but that
|
||
can cause trouble for first or last insn in a basic block. */
|
||
if (final && insn_is_dead)
|
||
{
|
||
rtx inote;
|
||
/* If the insn referred to a label, note that the label is
|
||
now less used. */
|
||
for (inote = REG_NOTES (insn); inote; inote = XEXP (inote, 1))
|
||
{
|
||
if (REG_NOTE_KIND (inote) == REG_LABEL)
|
||
{
|
||
rtx label = XEXP (inote, 0);
|
||
rtx next;
|
||
LABEL_NUSES (label)--;
|
||
|
||
/* If this label was attached to an ADDR_VEC, it's
|
||
safe to delete the ADDR_VEC. In fact, it's pretty much
|
||
mandatory to delete it, because the ADDR_VEC may
|
||
be referencing labels that no longer exist. */
|
||
if (LABEL_NUSES (label) == 0
|
||
&& (next = next_nonnote_insn (label)) != NULL
|
||
&& GET_CODE (next) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (next)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
|
||
{
|
||
rtx pat = PATTERN (next);
|
||
int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
|
||
int len = XVECLEN (pat, diff_vec_p);
|
||
int i;
|
||
for (i = 0; i < len; i++)
|
||
LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
|
||
|
||
flow_delete_insn (next);
|
||
}
|
||
}
|
||
}
|
||
|
||
PUT_CODE (insn, NOTE);
|
||
NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
|
||
NOTE_SOURCE_FILE (insn) = 0;
|
||
|
||
/* CC0 is now known to be dead. Either this insn used it,
|
||
in which case it doesn't anymore, or clobbered it,
|
||
so the next insn can't use it. */
|
||
cc0_live = 0;
|
||
|
||
/* If this insn is copying the return value from a library call,
|
||
delete the entire library call. */
|
||
if (libcall_is_dead)
|
||
{
|
||
rtx first = XEXP (note, 0);
|
||
rtx p = insn;
|
||
while (INSN_DELETED_P (first))
|
||
first = NEXT_INSN (first);
|
||
while (p != first)
|
||
{
|
||
p = PREV_INSN (p);
|
||
PUT_CODE (p, NOTE);
|
||
NOTE_LINE_NUMBER (p) = NOTE_INSN_DELETED;
|
||
NOTE_SOURCE_FILE (p) = 0;
|
||
}
|
||
}
|
||
goto flushed;
|
||
}
|
||
|
||
CLEAR_REG_SET (dead);
|
||
CLEAR_REG_SET (live);
|
||
|
||
/* See if this is an increment or decrement that can be
|
||
merged into a following memory address. */
|
||
#ifdef AUTO_INC_DEC
|
||
{
|
||
register rtx x = single_set (insn);
|
||
|
||
/* Does this instruction increment or decrement a register? */
|
||
if (!reload_completed
|
||
&& final && x != 0
|
||
&& GET_CODE (SET_DEST (x)) == REG
|
||
&& (GET_CODE (SET_SRC (x)) == PLUS
|
||
|| GET_CODE (SET_SRC (x)) == MINUS)
|
||
&& XEXP (SET_SRC (x), 0) == SET_DEST (x)
|
||
&& GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
|
||
/* Ok, look for a following memory ref we can combine with.
|
||
If one is found, change the memory ref to a PRE_INC
|
||
or PRE_DEC, cancel this insn, and return 1.
|
||
Return 0 if nothing has been done. */
|
||
&& try_pre_increment_1 (insn))
|
||
goto flushed;
|
||
}
|
||
#endif /* AUTO_INC_DEC */
|
||
|
||
/* If this is not the final pass, and this insn is copying the
|
||
value of a library call and it's dead, don't scan the
|
||
insns that perform the library call, so that the call's
|
||
arguments are not marked live. */
|
||
if (libcall_is_dead)
|
||
{
|
||
/* Mark the dest reg as `significant'. */
|
||
mark_set_regs (old, dead, PATTERN (insn), NULL_RTX, significant);
|
||
|
||
insn = XEXP (note, 0);
|
||
prev = PREV_INSN (insn);
|
||
}
|
||
else if (GET_CODE (PATTERN (insn)) == SET
|
||
&& SET_DEST (PATTERN (insn)) == stack_pointer_rtx
|
||
&& GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
|
||
&& XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
|
||
&& GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
|
||
/* We have an insn to pop a constant amount off the stack.
|
||
(Such insns use PLUS regardless of the direction of the stack,
|
||
and any insn to adjust the stack by a constant is always a pop.)
|
||
These insns, if not dead stores, have no effect on life. */
|
||
;
|
||
else
|
||
{
|
||
/* Any regs live at the time of a call instruction
|
||
must not go in a register clobbered by calls.
|
||
Find all regs now live and record this for them. */
|
||
|
||
if (GET_CODE (insn) == CALL_INSN && final)
|
||
EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
|
||
{
|
||
REG_N_CALLS_CROSSED (i)++;
|
||
});
|
||
|
||
/* LIVE gets the regs used in INSN;
|
||
DEAD gets those set by it. Dead insns don't make anything
|
||
live. */
|
||
|
||
mark_set_regs (old, dead, PATTERN (insn),
|
||
final ? insn : NULL_RTX, significant);
|
||
|
||
/* If an insn doesn't use CC0, it becomes dead since we
|
||
assume that every insn clobbers it. So show it dead here;
|
||
mark_used_regs will set it live if it is referenced. */
|
||
cc0_live = 0;
|
||
|
||
if (! insn_is_dead)
|
||
mark_used_regs (old, live, PATTERN (insn), final, insn);
|
||
|
||
/* Sometimes we may have inserted something before INSN (such as
|
||
a move) when we make an auto-inc. So ensure we will scan
|
||
those insns. */
|
||
#ifdef AUTO_INC_DEC
|
||
prev = PREV_INSN (insn);
|
||
#endif
|
||
|
||
if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
|
||
{
|
||
register int i;
|
||
|
||
rtx note;
|
||
|
||
for (note = CALL_INSN_FUNCTION_USAGE (insn);
|
||
note;
|
||
note = XEXP (note, 1))
|
||
if (GET_CODE (XEXP (note, 0)) == USE)
|
||
mark_used_regs (old, live, SET_DEST (XEXP (note, 0)),
|
||
final, insn);
|
||
|
||
/* Each call clobbers all call-clobbered regs that are not
|
||
global or fixed. Note that the function-value reg is a
|
||
call-clobbered reg, and mark_set_regs has already had
|
||
a chance to handle it. */
|
||
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (call_used_regs[i] && ! global_regs[i]
|
||
&& ! fixed_regs[i])
|
||
SET_REGNO_REG_SET (dead, i);
|
||
|
||
/* The stack ptr is used (honorarily) by a CALL insn. */
|
||
SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM);
|
||
|
||
/* Calls may also reference any of the global registers,
|
||
so they are made live. */
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (global_regs[i])
|
||
mark_used_regs (old, live,
|
||
gen_rtx_REG (reg_raw_mode[i], i),
|
||
final, insn);
|
||
|
||
/* Calls also clobber memory. */
|
||
mem_set_list = NULL_RTX;
|
||
}
|
||
|
||
/* Update OLD for the registers used or set. */
|
||
AND_COMPL_REG_SET (old, dead);
|
||
IOR_REG_SET (old, live);
|
||
|
||
}
|
||
|
||
/* On final pass, update counts of how many insns each reg is live
|
||
at. */
|
||
if (final)
|
||
EXECUTE_IF_SET_IN_REG_SET (old, 0, i,
|
||
{ REG_LIVE_LENGTH (i)++; });
|
||
}
|
||
flushed: ;
|
||
if (insn == first)
|
||
break;
|
||
}
|
||
|
||
FREE_REG_SET (dead);
|
||
FREE_REG_SET (live);
|
||
}
|
||
|
||
/* Return 1 if X (the body of an insn, or part of it) is just dead stores
|
||
(SET expressions whose destinations are registers dead after the insn).
|
||
NEEDED is the regset that says which regs are alive after the insn.
|
||
|
||
Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
|
||
|
||
If X is the entire body of an insn, NOTES contains the reg notes
|
||
pertaining to the insn. */
|
||
|
||
static int
|
||
insn_dead_p (x, needed, call_ok, notes)
|
||
rtx x;
|
||
regset needed;
|
||
int call_ok;
|
||
rtx notes ATTRIBUTE_UNUSED;
|
||
{
|
||
enum rtx_code code = GET_CODE (x);
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
/* If flow is invoked after reload, we must take existing AUTO_INC
|
||
expresions into account. */
|
||
if (reload_completed)
|
||
{
|
||
for ( ; notes; notes = XEXP (notes, 1))
|
||
{
|
||
if (REG_NOTE_KIND (notes) == REG_INC)
|
||
{
|
||
int regno = REGNO (XEXP (notes, 0));
|
||
|
||
/* Don't delete insns to set global regs. */
|
||
if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
|
||
|| REGNO_REG_SET_P (needed, regno))
|
||
return 0;
|
||
}
|
||
}
|
||
}
|
||
#endif
|
||
|
||
/* If setting something that's a reg or part of one,
|
||
see if that register's altered value will be live. */
|
||
|
||
if (code == SET)
|
||
{
|
||
rtx r = SET_DEST (x);
|
||
|
||
/* A SET that is a subroutine call cannot be dead. */
|
||
if (! call_ok && GET_CODE (SET_SRC (x)) == CALL)
|
||
return 0;
|
||
|
||
#ifdef HAVE_cc0
|
||
if (GET_CODE (r) == CC0)
|
||
return ! cc0_live;
|
||
#endif
|
||
|
||
if (GET_CODE (r) == MEM && ! MEM_VOLATILE_P (r))
|
||
{
|
||
rtx temp;
|
||
/* Walk the set of memory locations we are currently tracking
|
||
and see if one is an identical match to this memory location.
|
||
If so, this memory write is dead (remember, we're walking
|
||
backwards from the end of the block to the start. */
|
||
temp = mem_set_list;
|
||
while (temp)
|
||
{
|
||
if (rtx_equal_p (XEXP (temp, 0), r))
|
||
return 1;
|
||
temp = XEXP (temp, 1);
|
||
}
|
||
}
|
||
|
||
while (GET_CODE (r) == SUBREG || GET_CODE (r) == STRICT_LOW_PART
|
||
|| GET_CODE (r) == ZERO_EXTRACT)
|
||
r = SUBREG_REG (r);
|
||
|
||
if (GET_CODE (r) == REG)
|
||
{
|
||
int regno = REGNO (r);
|
||
|
||
/* Don't delete insns to set global regs. */
|
||
if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
|
||
/* Make sure insns to set frame pointer aren't deleted. */
|
||
|| (regno == FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
|
||
|| (regno == HARD_FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
#endif
|
||
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
|
||
/* Make sure insns to set arg pointer are never deleted
|
||
(if the arg pointer isn't fixed, there will be a USE for
|
||
it, so we can treat it normally). */
|
||
|| (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
|
||
#endif
|
||
|| REGNO_REG_SET_P (needed, regno))
|
||
return 0;
|
||
|
||
/* If this is a hard register, verify that subsequent words are
|
||
not needed. */
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
|
||
|
||
while (--n > 0)
|
||
if (REGNO_REG_SET_P (needed, regno+n))
|
||
return 0;
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
}
|
||
|
||
/* If performing several activities,
|
||
insn is dead if each activity is individually dead.
|
||
Also, CLOBBERs and USEs can be ignored; a CLOBBER or USE
|
||
that's inside a PARALLEL doesn't make the insn worth keeping. */
|
||
else if (code == PARALLEL)
|
||
{
|
||
int i = XVECLEN (x, 0);
|
||
|
||
for (i--; i >= 0; i--)
|
||
if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
|
||
&& GET_CODE (XVECEXP (x, 0, i)) != USE
|
||
&& ! insn_dead_p (XVECEXP (x, 0, i), needed, call_ok, NULL_RTX))
|
||
return 0;
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* A CLOBBER of a pseudo-register that is dead serves no purpose. That
|
||
is not necessarily true for hard registers. */
|
||
else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
|
||
&& REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
|
||
&& ! REGNO_REG_SET_P (needed, REGNO (XEXP (x, 0))))
|
||
return 1;
|
||
|
||
/* We do not check other CLOBBER or USE here. An insn consisting of just
|
||
a CLOBBER or just a USE should not be deleted. */
|
||
return 0;
|
||
}
|
||
|
||
/* If X is the pattern of the last insn in a libcall, and assuming X is dead,
|
||
return 1 if the entire library call is dead.
|
||
This is true if X copies a register (hard or pseudo)
|
||
and if the hard return reg of the call insn is dead.
|
||
(The caller should have tested the destination of X already for death.)
|
||
|
||
If this insn doesn't just copy a register, then we don't
|
||
have an ordinary libcall. In that case, cse could not have
|
||
managed to substitute the source for the dest later on,
|
||
so we can assume the libcall is dead.
|
||
|
||
NEEDED is the bit vector of pseudoregs live before this insn.
|
||
NOTE is the REG_RETVAL note of the insn. INSN is the insn itself. */
|
||
|
||
static int
|
||
libcall_dead_p (x, needed, note, insn)
|
||
rtx x;
|
||
regset needed;
|
||
rtx note;
|
||
rtx insn;
|
||
{
|
||
register RTX_CODE code = GET_CODE (x);
|
||
|
||
if (code == SET)
|
||
{
|
||
register rtx r = SET_SRC (x);
|
||
if (GET_CODE (r) == REG)
|
||
{
|
||
rtx call = XEXP (note, 0);
|
||
rtx call_pat;
|
||
register int i;
|
||
|
||
/* Find the call insn. */
|
||
while (call != insn && GET_CODE (call) != CALL_INSN)
|
||
call = NEXT_INSN (call);
|
||
|
||
/* If there is none, do nothing special,
|
||
since ordinary death handling can understand these insns. */
|
||
if (call == insn)
|
||
return 0;
|
||
|
||
/* See if the hard reg holding the value is dead.
|
||
If this is a PARALLEL, find the call within it. */
|
||
call_pat = PATTERN (call);
|
||
if (GET_CODE (call_pat) == PARALLEL)
|
||
{
|
||
for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
|
||
if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
|
||
&& GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
|
||
break;
|
||
|
||
/* This may be a library call that is returning a value
|
||
via invisible pointer. Do nothing special, since
|
||
ordinary death handling can understand these insns. */
|
||
if (i < 0)
|
||
return 0;
|
||
|
||
call_pat = XVECEXP (call_pat, 0, i);
|
||
}
|
||
|
||
return insn_dead_p (call_pat, needed, 1, REG_NOTES (call));
|
||
}
|
||
}
|
||
return 1;
|
||
}
|
||
|
||
/* Return 1 if register REGNO was used before it was set, i.e. if it is
|
||
live at function entry. Don't count global register variables, variables
|
||
in registers that can be used for function arg passing, or variables in
|
||
fixed hard registers. */
|
||
|
||
int
|
||
regno_uninitialized (regno)
|
||
int regno;
|
||
{
|
||
if (n_basic_blocks == 0
|
||
|| (regno < FIRST_PSEUDO_REGISTER
|
||
&& (global_regs[regno]
|
||
|| fixed_regs[regno]
|
||
|| FUNCTION_ARG_REGNO_P (regno))))
|
||
return 0;
|
||
|
||
return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
|
||
}
|
||
|
||
/* 1 if register REGNO was alive at a place where `setjmp' was called
|
||
and was set more than once or is an argument.
|
||
Such regs may be clobbered by `longjmp'. */
|
||
|
||
int
|
||
regno_clobbered_at_setjmp (regno)
|
||
int regno;
|
||
{
|
||
if (n_basic_blocks == 0)
|
||
return 0;
|
||
|
||
return ((REG_N_SETS (regno) > 1
|
||
|| REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
|
||
&& REGNO_REG_SET_P (regs_live_at_setjmp, regno));
|
||
}
|
||
|
||
/* INSN references memory, possibly using autoincrement addressing modes.
|
||
Find any entries on the mem_set_list that need to be invalidated due
|
||
to an address change. */
|
||
static void
|
||
invalidate_mems_from_autoinc (insn)
|
||
rtx insn;
|
||
{
|
||
rtx note = REG_NOTES (insn);
|
||
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
|
||
{
|
||
if (REG_NOTE_KIND (note) == REG_INC)
|
||
{
|
||
rtx temp = mem_set_list;
|
||
rtx prev = NULL_RTX;
|
||
|
||
while (temp)
|
||
{
|
||
if (reg_overlap_mentioned_p (XEXP (note, 0), XEXP (temp, 0)))
|
||
{
|
||
/* Splice temp out of list. */
|
||
if (prev)
|
||
XEXP (prev, 1) = XEXP (temp, 1);
|
||
else
|
||
mem_set_list = XEXP (temp, 1);
|
||
}
|
||
else
|
||
prev = temp;
|
||
temp = XEXP (temp, 1);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Process the registers that are set within X.
|
||
Their bits are set to 1 in the regset DEAD,
|
||
because they are dead prior to this insn.
|
||
|
||
If INSN is nonzero, it is the insn being processed
|
||
and the fact that it is nonzero implies this is the FINAL pass
|
||
in propagate_block. In this case, various info about register
|
||
usage is stored, LOG_LINKS fields of insns are set up. */
|
||
|
||
static void
|
||
mark_set_regs (needed, dead, x, insn, significant)
|
||
regset needed;
|
||
regset dead;
|
||
rtx x;
|
||
rtx insn;
|
||
regset significant;
|
||
{
|
||
register RTX_CODE code = GET_CODE (x);
|
||
|
||
if (code == SET || code == CLOBBER)
|
||
mark_set_1 (needed, dead, x, insn, significant);
|
||
else if (code == PARALLEL)
|
||
{
|
||
register int i;
|
||
for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
|
||
{
|
||
code = GET_CODE (XVECEXP (x, 0, i));
|
||
if (code == SET || code == CLOBBER)
|
||
mark_set_1 (needed, dead, XVECEXP (x, 0, i), insn, significant);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Process a single SET rtx, X. */
|
||
|
||
static void
|
||
mark_set_1 (needed, dead, x, insn, significant)
|
||
regset needed;
|
||
regset dead;
|
||
rtx x;
|
||
rtx insn;
|
||
regset significant;
|
||
{
|
||
register int regno;
|
||
register rtx reg = SET_DEST (x);
|
||
|
||
/* Some targets place small structures in registers for
|
||
return values of functions. We have to detect this
|
||
case specially here to get correct flow information. */
|
||
if (GET_CODE (reg) == PARALLEL
|
||
&& GET_MODE (reg) == BLKmode)
|
||
{
|
||
register int i;
|
||
|
||
for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
|
||
mark_set_1 (needed, dead, XVECEXP (reg, 0, i), insn, significant);
|
||
return;
|
||
}
|
||
|
||
/* Modifying just one hardware register of a multi-reg value
|
||
or just a byte field of a register
|
||
does not mean the value from before this insn is now dead.
|
||
But it does mean liveness of that register at the end of the block
|
||
is significant.
|
||
|
||
Within mark_set_1, however, we treat it as if the register is
|
||
indeed modified. mark_used_regs will, however, also treat this
|
||
register as being used. Thus, we treat these insns as setting a
|
||
new value for the register as a function of its old value. This
|
||
cases LOG_LINKS to be made appropriately and this will help combine. */
|
||
|
||
while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT
|
||
|| GET_CODE (reg) == SIGN_EXTRACT
|
||
|| GET_CODE (reg) == STRICT_LOW_PART)
|
||
reg = XEXP (reg, 0);
|
||
|
||
/* If this set is a MEM, then it kills any aliased writes.
|
||
If this set is a REG, then it kills any MEMs which use the reg. */
|
||
if (GET_CODE (reg) == MEM
|
||
|| GET_CODE (reg) == REG)
|
||
{
|
||
rtx temp = mem_set_list;
|
||
rtx prev = NULL_RTX;
|
||
|
||
while (temp)
|
||
{
|
||
if ((GET_CODE (reg) == MEM
|
||
&& output_dependence (XEXP (temp, 0), reg))
|
||
|| (GET_CODE (reg) == REG
|
||
&& reg_overlap_mentioned_p (reg, XEXP (temp, 0))))
|
||
{
|
||
/* Splice this entry out of the list. */
|
||
if (prev)
|
||
XEXP (prev, 1) = XEXP (temp, 1);
|
||
else
|
||
mem_set_list = XEXP (temp, 1);
|
||
}
|
||
else
|
||
prev = temp;
|
||
temp = XEXP (temp, 1);
|
||
}
|
||
}
|
||
|
||
/* If the memory reference had embedded side effects (autoincrement
|
||
address modes. Then we may need to kill some entries on the
|
||
memory set list. */
|
||
if (insn && GET_CODE (reg) == MEM)
|
||
invalidate_mems_from_autoinc (insn);
|
||
|
||
if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
|
||
/* We do not know the size of a BLKmode store, so we do not track
|
||
them for redundant store elimination. */
|
||
&& GET_MODE (reg) != BLKmode
|
||
/* There are no REG_INC notes for SP, so we can't assume we'll see
|
||
everything that invalidates it. To be safe, don't eliminate any
|
||
stores though SP; none of them should be redundant anyway. */
|
||
&& ! reg_mentioned_p (stack_pointer_rtx, reg))
|
||
mem_set_list = gen_rtx_EXPR_LIST (VOIDmode, reg, mem_set_list);
|
||
|
||
if (GET_CODE (reg) == REG
|
||
&& (regno = REGNO (reg), ! (regno == FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed)))
|
||
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
|
||
&& ! (regno == HARD_FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
#endif
|
||
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
|
||
&& ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
|
||
#endif
|
||
&& ! (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]))
|
||
/* && regno != STACK_POINTER_REGNUM) -- let's try without this. */
|
||
{
|
||
int some_needed = REGNO_REG_SET_P (needed, regno);
|
||
int some_not_needed = ! some_needed;
|
||
|
||
/* Mark it as a significant register for this basic block. */
|
||
if (significant)
|
||
SET_REGNO_REG_SET (significant, regno);
|
||
|
||
/* Mark it as dead before this insn. */
|
||
SET_REGNO_REG_SET (dead, regno);
|
||
|
||
/* A hard reg in a wide mode may really be multiple registers.
|
||
If so, mark all of them just like the first. */
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
int n;
|
||
|
||
/* Nothing below is needed for the stack pointer; get out asap.
|
||
Eg, log links aren't needed, since combine won't use them. */
|
||
if (regno == STACK_POINTER_REGNUM)
|
||
return;
|
||
|
||
n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
|
||
while (--n > 0)
|
||
{
|
||
int regno_n = regno + n;
|
||
int needed_regno = REGNO_REG_SET_P (needed, regno_n);
|
||
if (significant)
|
||
SET_REGNO_REG_SET (significant, regno_n);
|
||
|
||
SET_REGNO_REG_SET (dead, regno_n);
|
||
some_needed |= needed_regno;
|
||
some_not_needed |= ! needed_regno;
|
||
}
|
||
}
|
||
/* Additional data to record if this is the final pass. */
|
||
if (insn)
|
||
{
|
||
register rtx y = reg_next_use[regno];
|
||
register int blocknum = BLOCK_NUM (insn);
|
||
|
||
/* If this is a hard reg, record this function uses the reg. */
|
||
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
register int i;
|
||
int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg));
|
||
|
||
for (i = regno; i < endregno; i++)
|
||
{
|
||
/* The next use is no longer "next", since a store
|
||
intervenes. */
|
||
reg_next_use[i] = 0;
|
||
|
||
regs_ever_live[i] = 1;
|
||
REG_N_SETS (i)++;
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* The next use is no longer "next", since a store
|
||
intervenes. */
|
||
reg_next_use[regno] = 0;
|
||
|
||
/* Keep track of which basic blocks each reg appears in. */
|
||
|
||
if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
|
||
REG_BASIC_BLOCK (regno) = blocknum;
|
||
else if (REG_BASIC_BLOCK (regno) != blocknum)
|
||
REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
|
||
|
||
/* Count (weighted) references, stores, etc. This counts a
|
||
register twice if it is modified, but that is correct. */
|
||
REG_N_SETS (regno)++;
|
||
|
||
REG_N_REFS (regno) += loop_depth;
|
||
|
||
/* The insns where a reg is live are normally counted
|
||
elsewhere, but we want the count to include the insn
|
||
where the reg is set, and the normal counting mechanism
|
||
would not count it. */
|
||
REG_LIVE_LENGTH (regno)++;
|
||
}
|
||
|
||
if (! some_not_needed)
|
||
{
|
||
/* Make a logical link from the next following insn
|
||
that uses this register, back to this insn.
|
||
The following insns have already been processed.
|
||
|
||
We don't build a LOG_LINK for hard registers containing
|
||
in ASM_OPERANDs. If these registers get replaced,
|
||
we might wind up changing the semantics of the insn,
|
||
even if reload can make what appear to be valid assignments
|
||
later. */
|
||
if (y && (BLOCK_NUM (y) == blocknum)
|
||
&& (regno >= FIRST_PSEUDO_REGISTER
|
||
|| asm_noperands (PATTERN (y)) < 0))
|
||
LOG_LINKS (y)
|
||
= gen_rtx_INSN_LIST (VOIDmode, insn, LOG_LINKS (y));
|
||
}
|
||
else if (! some_needed)
|
||
{
|
||
/* Note that dead stores have already been deleted when possible
|
||
If we get here, we have found a dead store that cannot
|
||
be eliminated (because the same insn does something useful).
|
||
Indicate this by marking the reg being set as dying here. */
|
||
REG_NOTES (insn)
|
||
= gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
|
||
REG_N_DEATHS (REGNO (reg))++;
|
||
}
|
||
else
|
||
{
|
||
/* This is a case where we have a multi-word hard register
|
||
and some, but not all, of the words of the register are
|
||
needed in subsequent insns. Write REG_UNUSED notes
|
||
for those parts that were not needed. This case should
|
||
be rare. */
|
||
|
||
int i;
|
||
|
||
for (i = HARD_REGNO_NREGS (regno, GET_MODE (reg)) - 1;
|
||
i >= 0; i--)
|
||
if (!REGNO_REG_SET_P (needed, regno + i))
|
||
REG_NOTES (insn)
|
||
= gen_rtx_EXPR_LIST (REG_UNUSED,
|
||
gen_rtx_REG (reg_raw_mode[regno + i],
|
||
regno + i),
|
||
REG_NOTES (insn));
|
||
}
|
||
}
|
||
}
|
||
else if (GET_CODE (reg) == REG)
|
||
reg_next_use[regno] = 0;
|
||
|
||
/* If this is the last pass and this is a SCRATCH, show it will be dying
|
||
here and count it. */
|
||
else if (GET_CODE (reg) == SCRATCH && insn != 0)
|
||
{
|
||
REG_NOTES (insn)
|
||
= gen_rtx_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
|
||
}
|
||
}
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
|
||
/* X is a MEM found in INSN. See if we can convert it into an auto-increment
|
||
reference. */
|
||
|
||
static void
|
||
find_auto_inc (needed, x, insn)
|
||
regset needed;
|
||
rtx x;
|
||
rtx insn;
|
||
{
|
||
rtx addr = XEXP (x, 0);
|
||
HOST_WIDE_INT offset = 0;
|
||
rtx set;
|
||
|
||
/* Here we detect use of an index register which might be good for
|
||
postincrement, postdecrement, preincrement, or predecrement. */
|
||
|
||
if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
|
||
offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
|
||
|
||
if (GET_CODE (addr) == REG)
|
||
{
|
||
register rtx y;
|
||
register int size = GET_MODE_SIZE (GET_MODE (x));
|
||
rtx use;
|
||
rtx incr;
|
||
int regno = REGNO (addr);
|
||
|
||
/* Is the next use an increment that might make auto-increment? */
|
||
if ((incr = reg_next_use[regno]) != 0
|
||
&& (set = single_set (incr)) != 0
|
||
&& GET_CODE (set) == SET
|
||
&& BLOCK_NUM (incr) == BLOCK_NUM (insn)
|
||
/* Can't add side effects to jumps; if reg is spilled and
|
||
reloaded, there's no way to store back the altered value. */
|
||
&& GET_CODE (insn) != JUMP_INSN
|
||
&& (y = SET_SRC (set), GET_CODE (y) == PLUS)
|
||
&& XEXP (y, 0) == addr
|
||
&& GET_CODE (XEXP (y, 1)) == CONST_INT
|
||
&& ((HAVE_POST_INCREMENT
|
||
&& (INTVAL (XEXP (y, 1)) == size && offset == 0))
|
||
|| (HAVE_POST_DECREMENT
|
||
&& (INTVAL (XEXP (y, 1)) == - size && offset == 0))
|
||
|| (HAVE_PRE_INCREMENT
|
||
&& (INTVAL (XEXP (y, 1)) == size && offset == size))
|
||
|| (HAVE_PRE_DECREMENT
|
||
&& (INTVAL (XEXP (y, 1)) == - size && offset == - size)))
|
||
/* Make sure this reg appears only once in this insn. */
|
||
&& (use = find_use_as_address (PATTERN (insn), addr, offset),
|
||
use != 0 && use != (rtx) 1))
|
||
{
|
||
rtx q = SET_DEST (set);
|
||
enum rtx_code inc_code = (INTVAL (XEXP (y, 1)) == size
|
||
? (offset ? PRE_INC : POST_INC)
|
||
: (offset ? PRE_DEC : POST_DEC));
|
||
|
||
if (dead_or_set_p (incr, addr))
|
||
{
|
||
/* This is the simple case. Try to make the auto-inc. If
|
||
we can't, we are done. Otherwise, we will do any
|
||
needed updates below. */
|
||
if (! validate_change (insn, &XEXP (x, 0),
|
||
gen_rtx_fmt_e (inc_code, Pmode, addr),
|
||
0))
|
||
return;
|
||
}
|
||
else if (GET_CODE (q) == REG
|
||
/* PREV_INSN used here to check the semi-open interval
|
||
[insn,incr). */
|
||
&& ! reg_used_between_p (q, PREV_INSN (insn), incr)
|
||
/* We must also check for sets of q as q may be
|
||
a call clobbered hard register and there may
|
||
be a call between PREV_INSN (insn) and incr. */
|
||
&& ! reg_set_between_p (q, PREV_INSN (insn), incr))
|
||
{
|
||
/* We have *p followed sometime later by q = p+size.
|
||
Both p and q must be live afterward,
|
||
and q is not used between INSN and its assignment.
|
||
Change it to q = p, ...*q..., q = q+size.
|
||
Then fall into the usual case. */
|
||
rtx insns, temp;
|
||
basic_block bb;
|
||
|
||
start_sequence ();
|
||
emit_move_insn (q, addr);
|
||
insns = get_insns ();
|
||
end_sequence ();
|
||
|
||
bb = BLOCK_FOR_INSN (insn);
|
||
for (temp = insns; temp; temp = NEXT_INSN (temp))
|
||
set_block_for_insn (temp, bb);
|
||
|
||
/* If we can't make the auto-inc, or can't make the
|
||
replacement into Y, exit. There's no point in making
|
||
the change below if we can't do the auto-inc and doing
|
||
so is not correct in the pre-inc case. */
|
||
|
||
validate_change (insn, &XEXP (x, 0),
|
||
gen_rtx_fmt_e (inc_code, Pmode, q),
|
||
1);
|
||
validate_change (incr, &XEXP (y, 0), q, 1);
|
||
if (! apply_change_group ())
|
||
return;
|
||
|
||
/* We now know we'll be doing this change, so emit the
|
||
new insn(s) and do the updates. */
|
||
emit_insns_before (insns, insn);
|
||
|
||
if (BLOCK_FOR_INSN (insn)->head == insn)
|
||
BLOCK_FOR_INSN (insn)->head = insns;
|
||
|
||
/* INCR will become a NOTE and INSN won't contain a
|
||
use of ADDR. If a use of ADDR was just placed in
|
||
the insn before INSN, make that the next use.
|
||
Otherwise, invalidate it. */
|
||
if (GET_CODE (PREV_INSN (insn)) == INSN
|
||
&& GET_CODE (PATTERN (PREV_INSN (insn))) == SET
|
||
&& SET_SRC (PATTERN (PREV_INSN (insn))) == addr)
|
||
reg_next_use[regno] = PREV_INSN (insn);
|
||
else
|
||
reg_next_use[regno] = 0;
|
||
|
||
addr = q;
|
||
regno = REGNO (q);
|
||
|
||
/* REGNO is now used in INCR which is below INSN, but
|
||
it previously wasn't live here. If we don't mark
|
||
it as needed, we'll put a REG_DEAD note for it
|
||
on this insn, which is incorrect. */
|
||
SET_REGNO_REG_SET (needed, regno);
|
||
|
||
/* If there are any calls between INSN and INCR, show
|
||
that REGNO now crosses them. */
|
||
for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
|
||
if (GET_CODE (temp) == CALL_INSN)
|
||
REG_N_CALLS_CROSSED (regno)++;
|
||
}
|
||
else
|
||
return;
|
||
|
||
/* If we haven't returned, it means we were able to make the
|
||
auto-inc, so update the status. First, record that this insn
|
||
has an implicit side effect. */
|
||
|
||
REG_NOTES (insn)
|
||
= gen_rtx_EXPR_LIST (REG_INC, addr, REG_NOTES (insn));
|
||
|
||
/* Modify the old increment-insn to simply copy
|
||
the already-incremented value of our register. */
|
||
if (! validate_change (incr, &SET_SRC (set), addr, 0))
|
||
abort ();
|
||
|
||
/* If that makes it a no-op (copying the register into itself) delete
|
||
it so it won't appear to be a "use" and a "set" of this
|
||
register. */
|
||
if (SET_DEST (set) == addr)
|
||
{
|
||
PUT_CODE (incr, NOTE);
|
||
NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
|
||
NOTE_SOURCE_FILE (incr) = 0;
|
||
}
|
||
|
||
if (regno >= FIRST_PSEUDO_REGISTER)
|
||
{
|
||
/* Count an extra reference to the reg. When a reg is
|
||
incremented, spilling it is worse, so we want to make
|
||
that less likely. */
|
||
REG_N_REFS (regno) += loop_depth;
|
||
|
||
/* Count the increment as a setting of the register,
|
||
even though it isn't a SET in rtl. */
|
||
REG_N_SETS (regno)++;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
#endif /* AUTO_INC_DEC */
|
||
|
||
/* Scan expression X and store a 1-bit in LIVE for each reg it uses.
|
||
This is done assuming the registers needed from X
|
||
are those that have 1-bits in NEEDED.
|
||
|
||
On the final pass, FINAL is 1. This means try for autoincrement
|
||
and count the uses and deaths of each pseudo-reg.
|
||
|
||
INSN is the containing instruction. If INSN is dead, this function is not
|
||
called. */
|
||
|
||
static void
|
||
mark_used_regs (needed, live, x, final, insn)
|
||
regset needed;
|
||
regset live;
|
||
rtx x;
|
||
int final;
|
||
rtx insn;
|
||
{
|
||
register RTX_CODE code;
|
||
register int regno;
|
||
int i;
|
||
|
||
retry:
|
||
code = GET_CODE (x);
|
||
switch (code)
|
||
{
|
||
case LABEL_REF:
|
||
case SYMBOL_REF:
|
||
case CONST_INT:
|
||
case CONST:
|
||
case CONST_DOUBLE:
|
||
case PC:
|
||
case ADDR_VEC:
|
||
case ADDR_DIFF_VEC:
|
||
return;
|
||
|
||
#ifdef HAVE_cc0
|
||
case CC0:
|
||
cc0_live = 1;
|
||
return;
|
||
#endif
|
||
|
||
case CLOBBER:
|
||
/* If we are clobbering a MEM, mark any registers inside the address
|
||
as being used. */
|
||
if (GET_CODE (XEXP (x, 0)) == MEM)
|
||
mark_used_regs (needed, live, XEXP (XEXP (x, 0), 0), final, insn);
|
||
return;
|
||
|
||
case MEM:
|
||
/* Invalidate the data for the last MEM stored, but only if MEM is
|
||
something that can be stored into. */
|
||
if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
|
||
&& CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
|
||
; /* needn't clear the memory set list */
|
||
else
|
||
{
|
||
rtx temp = mem_set_list;
|
||
rtx prev = NULL_RTX;
|
||
|
||
while (temp)
|
||
{
|
||
if (anti_dependence (XEXP (temp, 0), x))
|
||
{
|
||
/* Splice temp out of the list. */
|
||
if (prev)
|
||
XEXP (prev, 1) = XEXP (temp, 1);
|
||
else
|
||
mem_set_list = XEXP (temp, 1);
|
||
}
|
||
else
|
||
prev = temp;
|
||
temp = XEXP (temp, 1);
|
||
}
|
||
}
|
||
|
||
/* If the memory reference had embedded side effects (autoincrement
|
||
address modes. Then we may need to kill some entries on the
|
||
memory set list. */
|
||
if (insn)
|
||
invalidate_mems_from_autoinc (insn);
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
if (final)
|
||
find_auto_inc (needed, x, insn);
|
||
#endif
|
||
break;
|
||
|
||
case SUBREG:
|
||
if (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)))))
|
||
REG_CHANGES_SIZE (REGNO (SUBREG_REG (x))) = 1;
|
||
|
||
/* While we're here, optimize this case. */
|
||
x = SUBREG_REG (x);
|
||
|
||
/* In case the SUBREG is not of a register, don't optimize */
|
||
if (GET_CODE (x) != REG)
|
||
{
|
||
mark_used_regs (needed, live, x, final, insn);
|
||
return;
|
||
}
|
||
|
||
/* ... fall through ... */
|
||
|
||
case REG:
|
||
/* See a register other than being set
|
||
=> mark it as needed. */
|
||
|
||
regno = REGNO (x);
|
||
{
|
||
int some_needed = REGNO_REG_SET_P (needed, regno);
|
||
int some_not_needed = ! some_needed;
|
||
|
||
SET_REGNO_REG_SET (live, regno);
|
||
|
||
/* A hard reg in a wide mode may really be multiple registers.
|
||
If so, mark all of them just like the first. */
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
int n;
|
||
|
||
/* For stack ptr or fixed arg pointer,
|
||
nothing below can be necessary, so waste no more time. */
|
||
if (regno == STACK_POINTER_REGNUM
|
||
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
|
||
|| (regno == HARD_FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
#endif
|
||
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
|
||
|| (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
|
||
#endif
|
||
|| (regno == FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed)))
|
||
{
|
||
/* If this is a register we are going to try to eliminate,
|
||
don't mark it live here. If we are successful in
|
||
eliminating it, it need not be live unless it is used for
|
||
pseudos, in which case it will have been set live when
|
||
it was allocated to the pseudos. If the register will not
|
||
be eliminated, reload will set it live at that point. */
|
||
|
||
if (! TEST_HARD_REG_BIT (elim_reg_set, regno))
|
||
regs_ever_live[regno] = 1;
|
||
return;
|
||
}
|
||
/* No death notes for global register variables;
|
||
their values are live after this function exits. */
|
||
if (global_regs[regno])
|
||
{
|
||
if (final)
|
||
reg_next_use[regno] = insn;
|
||
return;
|
||
}
|
||
|
||
n = HARD_REGNO_NREGS (regno, GET_MODE (x));
|
||
while (--n > 0)
|
||
{
|
||
int regno_n = regno + n;
|
||
int needed_regno = REGNO_REG_SET_P (needed, regno_n);
|
||
|
||
SET_REGNO_REG_SET (live, regno_n);
|
||
some_needed |= needed_regno;
|
||
some_not_needed |= ! needed_regno;
|
||
}
|
||
}
|
||
if (final)
|
||
{
|
||
/* Record where each reg is used, so when the reg
|
||
is set we know the next insn that uses it. */
|
||
|
||
reg_next_use[regno] = insn;
|
||
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
/* If a hard reg is being used,
|
||
record that this function does use it. */
|
||
|
||
i = HARD_REGNO_NREGS (regno, GET_MODE (x));
|
||
if (i == 0)
|
||
i = 1;
|
||
do
|
||
regs_ever_live[regno + --i] = 1;
|
||
while (i > 0);
|
||
}
|
||
else
|
||
{
|
||
/* Keep track of which basic block each reg appears in. */
|
||
|
||
register int blocknum = BLOCK_NUM (insn);
|
||
|
||
if (REG_BASIC_BLOCK (regno) == REG_BLOCK_UNKNOWN)
|
||
REG_BASIC_BLOCK (regno) = blocknum;
|
||
else if (REG_BASIC_BLOCK (regno) != blocknum)
|
||
REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL;
|
||
|
||
/* Count (weighted) number of uses of each reg. */
|
||
|
||
REG_N_REFS (regno) += loop_depth;
|
||
}
|
||
|
||
/* Record and count the insns in which a reg dies.
|
||
If it is used in this insn and was dead below the insn
|
||
then it dies in this insn. If it was set in this insn,
|
||
we do not make a REG_DEAD note; likewise if we already
|
||
made such a note. */
|
||
|
||
if (some_not_needed
|
||
&& ! dead_or_set_p (insn, x)
|
||
#if 0
|
||
&& (regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
|
||
#endif
|
||
)
|
||
{
|
||
/* Check for the case where the register dying partially
|
||
overlaps the register set by this insn. */
|
||
if (regno < FIRST_PSEUDO_REGISTER
|
||
&& HARD_REGNO_NREGS (regno, GET_MODE (x)) > 1)
|
||
{
|
||
int n = HARD_REGNO_NREGS (regno, GET_MODE (x));
|
||
while (--n >= 0)
|
||
some_needed |= dead_or_set_regno_p (insn, regno + n);
|
||
}
|
||
|
||
/* If none of the words in X is needed, make a REG_DEAD
|
||
note. Otherwise, we must make partial REG_DEAD notes. */
|
||
if (! some_needed)
|
||
{
|
||
REG_NOTES (insn)
|
||
= gen_rtx_EXPR_LIST (REG_DEAD, x, REG_NOTES (insn));
|
||
REG_N_DEATHS (regno)++;
|
||
}
|
||
else
|
||
{
|
||
int i;
|
||
|
||
/* Don't make a REG_DEAD note for a part of a register
|
||
that is set in the insn. */
|
||
|
||
for (i = HARD_REGNO_NREGS (regno, GET_MODE (x)) - 1;
|
||
i >= 0; i--)
|
||
if (!REGNO_REG_SET_P (needed, regno + i)
|
||
&& ! dead_or_set_regno_p (insn, regno + i))
|
||
REG_NOTES (insn)
|
||
= gen_rtx_EXPR_LIST (REG_DEAD,
|
||
gen_rtx_REG (reg_raw_mode[regno + i],
|
||
regno + i),
|
||
REG_NOTES (insn));
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return;
|
||
|
||
case SET:
|
||
{
|
||
register rtx testreg = SET_DEST (x);
|
||
int mark_dest = 0;
|
||
|
||
/* If storing into MEM, don't show it as being used. But do
|
||
show the address as being used. */
|
||
if (GET_CODE (testreg) == MEM)
|
||
{
|
||
#ifdef AUTO_INC_DEC
|
||
if (final)
|
||
find_auto_inc (needed, testreg, insn);
|
||
#endif
|
||
mark_used_regs (needed, live, XEXP (testreg, 0), final, insn);
|
||
mark_used_regs (needed, live, SET_SRC (x), final, insn);
|
||
return;
|
||
}
|
||
|
||
/* Storing in STRICT_LOW_PART is like storing in a reg
|
||
in that this SET might be dead, so ignore it in TESTREG.
|
||
but in some other ways it is like using the reg.
|
||
|
||
Storing in a SUBREG or a bit field is like storing the entire
|
||
register in that if the register's value is not used
|
||
then this SET is not needed. */
|
||
while (GET_CODE (testreg) == STRICT_LOW_PART
|
||
|| GET_CODE (testreg) == ZERO_EXTRACT
|
||
|| GET_CODE (testreg) == SIGN_EXTRACT
|
||
|| GET_CODE (testreg) == SUBREG)
|
||
{
|
||
if (GET_CODE (testreg) == SUBREG
|
||
&& GET_CODE (SUBREG_REG (testreg)) == REG
|
||
&& REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
|
||
&& (GET_MODE_SIZE (GET_MODE (testreg))
|
||
!= GET_MODE_SIZE (GET_MODE (SUBREG_REG (testreg)))))
|
||
REG_CHANGES_SIZE (REGNO (SUBREG_REG (testreg))) = 1;
|
||
|
||
/* Modifying a single register in an alternate mode
|
||
does not use any of the old value. But these other
|
||
ways of storing in a register do use the old value. */
|
||
if (GET_CODE (testreg) == SUBREG
|
||
&& !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
|
||
;
|
||
else
|
||
mark_dest = 1;
|
||
|
||
testreg = XEXP (testreg, 0);
|
||
}
|
||
|
||
/* If this is a store into a register,
|
||
recursively scan the value being stored. */
|
||
|
||
if ((GET_CODE (testreg) == PARALLEL
|
||
&& GET_MODE (testreg) == BLKmode)
|
||
|| (GET_CODE (testreg) == REG
|
||
&& (regno = REGNO (testreg), ! (regno == FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed)))
|
||
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
|
||
&& ! (regno == HARD_FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
#endif
|
||
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
|
||
&& ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
|
||
#endif
|
||
))
|
||
/* We used to exclude global_regs here, but that seems wrong.
|
||
Storing in them is like storing in mem. */
|
||
{
|
||
mark_used_regs (needed, live, SET_SRC (x), final, insn);
|
||
if (mark_dest)
|
||
mark_used_regs (needed, live, SET_DEST (x), final, insn);
|
||
return;
|
||
}
|
||
}
|
||
break;
|
||
|
||
case RETURN:
|
||
/* If exiting needs the right stack value, consider this insn as
|
||
using the stack pointer. In any event, consider it as using
|
||
all global registers and all registers used by return. */
|
||
if (! EXIT_IGNORE_STACK
|
||
|| (! FRAME_POINTER_REQUIRED
|
||
&& ! current_function_calls_alloca
|
||
&& flag_omit_frame_pointer)
|
||
|| current_function_sp_is_unchanging)
|
||
SET_REGNO_REG_SET (live, STACK_POINTER_REGNUM);
|
||
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (global_regs[i]
|
||
#ifdef EPILOGUE_USES
|
||
|| EPILOGUE_USES (i)
|
||
#endif
|
||
)
|
||
SET_REGNO_REG_SET (live, i);
|
||
break;
|
||
|
||
case ASM_OPERANDS:
|
||
case UNSPEC_VOLATILE:
|
||
case TRAP_IF:
|
||
case ASM_INPUT:
|
||
{
|
||
/* Traditional and volatile asm instructions must be considered to use
|
||
and clobber all hard registers, all pseudo-registers and all of
|
||
memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
|
||
|
||
Consider for instance a volatile asm that changes the fpu rounding
|
||
mode. An insn should not be moved across this even if it only uses
|
||
pseudo-regs because it might give an incorrectly rounded result.
|
||
|
||
?!? Unfortunately, marking all hard registers as live causes massive
|
||
problems for the register allocator and marking all pseudos as live
|
||
creates mountains of uninitialized variable warnings.
|
||
|
||
So for now, just clear the memory set list and mark any regs
|
||
we can find in ASM_OPERANDS as used. */
|
||
if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
|
||
mem_set_list = NULL_RTX;
|
||
|
||
/* For all ASM_OPERANDS, we must traverse the vector of input operands.
|
||
We can not just fall through here since then we would be confused
|
||
by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
|
||
traditional asms unlike their normal usage. */
|
||
if (code == ASM_OPERANDS)
|
||
{
|
||
int j;
|
||
|
||
for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
|
||
mark_used_regs (needed, live, ASM_OPERANDS_INPUT (x, j),
|
||
final, insn);
|
||
}
|
||
break;
|
||
}
|
||
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* Recursively scan the operands of this expression. */
|
||
|
||
{
|
||
register char *fmt = GET_RTX_FORMAT (code);
|
||
register int i;
|
||
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
{
|
||
/* Tail recursive case: save a function call level. */
|
||
if (i == 0)
|
||
{
|
||
x = XEXP (x, 0);
|
||
goto retry;
|
||
}
|
||
mark_used_regs (needed, live, XEXP (x, i), final, insn);
|
||
}
|
||
else if (fmt[i] == 'E')
|
||
{
|
||
register int j;
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
mark_used_regs (needed, live, XVECEXP (x, i, j), final, insn);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
|
||
static int
|
||
try_pre_increment_1 (insn)
|
||
rtx insn;
|
||
{
|
||
/* Find the next use of this reg. If in same basic block,
|
||
make it do pre-increment or pre-decrement if appropriate. */
|
||
rtx x = single_set (insn);
|
||
HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
|
||
* INTVAL (XEXP (SET_SRC (x), 1)));
|
||
int regno = REGNO (SET_DEST (x));
|
||
rtx y = reg_next_use[regno];
|
||
if (y != 0
|
||
&& BLOCK_NUM (y) == BLOCK_NUM (insn)
|
||
/* Don't do this if the reg dies, or gets set in y; a standard addressing
|
||
mode would be better. */
|
||
&& ! dead_or_set_p (y, SET_DEST (x))
|
||
&& try_pre_increment (y, SET_DEST (x), amount))
|
||
{
|
||
/* We have found a suitable auto-increment
|
||
and already changed insn Y to do it.
|
||
So flush this increment-instruction. */
|
||
PUT_CODE (insn, NOTE);
|
||
NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
|
||
NOTE_SOURCE_FILE (insn) = 0;
|
||
/* Count a reference to this reg for the increment
|
||
insn we are deleting. When a reg is incremented.
|
||
spilling it is worse, so we want to make that
|
||
less likely. */
|
||
if (regno >= FIRST_PSEUDO_REGISTER)
|
||
{
|
||
REG_N_REFS (regno) += loop_depth;
|
||
REG_N_SETS (regno)++;
|
||
}
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Try to change INSN so that it does pre-increment or pre-decrement
|
||
addressing on register REG in order to add AMOUNT to REG.
|
||
AMOUNT is negative for pre-decrement.
|
||
Returns 1 if the change could be made.
|
||
This checks all about the validity of the result of modifying INSN. */
|
||
|
||
static int
|
||
try_pre_increment (insn, reg, amount)
|
||
rtx insn, reg;
|
||
HOST_WIDE_INT amount;
|
||
{
|
||
register rtx use;
|
||
|
||
/* Nonzero if we can try to make a pre-increment or pre-decrement.
|
||
For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
|
||
int pre_ok = 0;
|
||
/* Nonzero if we can try to make a post-increment or post-decrement.
|
||
For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
|
||
It is possible for both PRE_OK and POST_OK to be nonzero if the machine
|
||
supports both pre-inc and post-inc, or both pre-dec and post-dec. */
|
||
int post_ok = 0;
|
||
|
||
/* Nonzero if the opportunity actually requires post-inc or post-dec. */
|
||
int do_post = 0;
|
||
|
||
/* From the sign of increment, see which possibilities are conceivable
|
||
on this target machine. */
|
||
if (HAVE_PRE_INCREMENT && amount > 0)
|
||
pre_ok = 1;
|
||
if (HAVE_POST_INCREMENT && amount > 0)
|
||
post_ok = 1;
|
||
|
||
if (HAVE_PRE_DECREMENT && amount < 0)
|
||
pre_ok = 1;
|
||
if (HAVE_POST_DECREMENT && amount < 0)
|
||
post_ok = 1;
|
||
|
||
if (! (pre_ok || post_ok))
|
||
return 0;
|
||
|
||
/* It is not safe to add a side effect to a jump insn
|
||
because if the incremented register is spilled and must be reloaded
|
||
there would be no way to store the incremented value back in memory. */
|
||
|
||
if (GET_CODE (insn) == JUMP_INSN)
|
||
return 0;
|
||
|
||
use = 0;
|
||
if (pre_ok)
|
||
use = find_use_as_address (PATTERN (insn), reg, 0);
|
||
if (post_ok && (use == 0 || use == (rtx) 1))
|
||
{
|
||
use = find_use_as_address (PATTERN (insn), reg, -amount);
|
||
do_post = 1;
|
||
}
|
||
|
||
if (use == 0 || use == (rtx) 1)
|
||
return 0;
|
||
|
||
if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
|
||
return 0;
|
||
|
||
/* See if this combination of instruction and addressing mode exists. */
|
||
if (! validate_change (insn, &XEXP (use, 0),
|
||
gen_rtx_fmt_e (amount > 0
|
||
? (do_post ? POST_INC : PRE_INC)
|
||
: (do_post ? POST_DEC : PRE_DEC),
|
||
Pmode, reg), 0))
|
||
return 0;
|
||
|
||
/* Record that this insn now has an implicit side effect on X. */
|
||
REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
|
||
return 1;
|
||
}
|
||
|
||
#endif /* AUTO_INC_DEC */
|
||
|
||
/* Find the place in the rtx X where REG is used as a memory address.
|
||
Return the MEM rtx that so uses it.
|
||
If PLUSCONST is nonzero, search instead for a memory address equivalent to
|
||
(plus REG (const_int PLUSCONST)).
|
||
|
||
If such an address does not appear, return 0.
|
||
If REG appears more than once, or is used other than in such an address,
|
||
return (rtx)1. */
|
||
|
||
rtx
|
||
find_use_as_address (x, reg, plusconst)
|
||
register rtx x;
|
||
rtx reg;
|
||
HOST_WIDE_INT plusconst;
|
||
{
|
||
enum rtx_code code = GET_CODE (x);
|
||
char *fmt = GET_RTX_FORMAT (code);
|
||
register int i;
|
||
register rtx value = 0;
|
||
register rtx tem;
|
||
|
||
if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
|
||
return x;
|
||
|
||
if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
|
||
&& XEXP (XEXP (x, 0), 0) == reg
|
||
&& GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
|
||
&& INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
|
||
return x;
|
||
|
||
if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
|
||
{
|
||
/* If REG occurs inside a MEM used in a bit-field reference,
|
||
that is unacceptable. */
|
||
if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
|
||
return (rtx) (HOST_WIDE_INT) 1;
|
||
}
|
||
|
||
if (x == reg)
|
||
return (rtx) (HOST_WIDE_INT) 1;
|
||
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
{
|
||
tem = find_use_as_address (XEXP (x, i), reg, plusconst);
|
||
if (value == 0)
|
||
value = tem;
|
||
else if (tem != 0)
|
||
return (rtx) (HOST_WIDE_INT) 1;
|
||
}
|
||
if (fmt[i] == 'E')
|
||
{
|
||
register int j;
|
||
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
|
||
{
|
||
tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
|
||
if (value == 0)
|
||
value = tem;
|
||
else if (tem != 0)
|
||
return (rtx) (HOST_WIDE_INT) 1;
|
||
}
|
||
}
|
||
}
|
||
|
||
return value;
|
||
}
|
||
|
||
/* Write information about registers and basic blocks into FILE.
|
||
This is part of making a debugging dump. */
|
||
|
||
void
|
||
dump_flow_info (file)
|
||
FILE *file;
|
||
{
|
||
register int i;
|
||
static char *reg_class_names[] = REG_CLASS_NAMES;
|
||
|
||
fprintf (file, "%d registers.\n", max_regno);
|
||
for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
|
||
if (REG_N_REFS (i))
|
||
{
|
||
enum reg_class class, altclass;
|
||
fprintf (file, "\nRegister %d used %d times across %d insns",
|
||
i, REG_N_REFS (i), REG_LIVE_LENGTH (i));
|
||
if (REG_BASIC_BLOCK (i) >= 0)
|
||
fprintf (file, " in block %d", REG_BASIC_BLOCK (i));
|
||
if (REG_N_SETS (i))
|
||
fprintf (file, "; set %d time%s", REG_N_SETS (i),
|
||
(REG_N_SETS (i) == 1) ? "" : "s");
|
||
if (REG_USERVAR_P (regno_reg_rtx[i]))
|
||
fprintf (file, "; user var");
|
||
if (REG_N_DEATHS (i) != 1)
|
||
fprintf (file, "; dies in %d places", REG_N_DEATHS (i));
|
||
if (REG_N_CALLS_CROSSED (i) == 1)
|
||
fprintf (file, "; crosses 1 call");
|
||
else if (REG_N_CALLS_CROSSED (i))
|
||
fprintf (file, "; crosses %d calls", REG_N_CALLS_CROSSED (i));
|
||
if (PSEUDO_REGNO_BYTES (i) != UNITS_PER_WORD)
|
||
fprintf (file, "; %d bytes", PSEUDO_REGNO_BYTES (i));
|
||
class = reg_preferred_class (i);
|
||
altclass = reg_alternate_class (i);
|
||
if (class != GENERAL_REGS || altclass != ALL_REGS)
|
||
{
|
||
if (altclass == ALL_REGS || class == ALL_REGS)
|
||
fprintf (file, "; pref %s", reg_class_names[(int) class]);
|
||
else if (altclass == NO_REGS)
|
||
fprintf (file, "; %s or none", reg_class_names[(int) class]);
|
||
else
|
||
fprintf (file, "; pref %s, else %s",
|
||
reg_class_names[(int) class],
|
||
reg_class_names[(int) altclass]);
|
||
}
|
||
if (REGNO_POINTER_FLAG (i))
|
||
fprintf (file, "; pointer");
|
||
fprintf (file, ".\n");
|
||
}
|
||
|
||
fprintf (file, "\n%d basic blocks.\n", n_basic_blocks);
|
||
for (i = 0; i < n_basic_blocks; i++)
|
||
{
|
||
register basic_block bb = BASIC_BLOCK (i);
|
||
register int regno;
|
||
register edge e;
|
||
|
||
fprintf (file, "\nBasic block %d: first insn %d, last %d.\n",
|
||
i, INSN_UID (bb->head), INSN_UID (bb->end));
|
||
|
||
fprintf (file, "Predecessors: ");
|
||
for (e = bb->pred; e ; e = e->pred_next)
|
||
dump_edge_info (file, e, 0);
|
||
|
||
fprintf (file, "\nSuccessors: ");
|
||
for (e = bb->succ; e ; e = e->succ_next)
|
||
dump_edge_info (file, e, 1);
|
||
|
||
fprintf (file, "\nRegisters live at start:");
|
||
if (bb->global_live_at_start)
|
||
{
|
||
for (regno = 0; regno < max_regno; regno++)
|
||
if (REGNO_REG_SET_P (bb->global_live_at_start, regno))
|
||
fprintf (file, " %d", regno);
|
||
}
|
||
else
|
||
fprintf (file, " n/a");
|
||
|
||
fprintf (file, "\nRegisters live at end:");
|
||
if (bb->global_live_at_end)
|
||
{
|
||
for (regno = 0; regno < max_regno; regno++)
|
||
if (REGNO_REG_SET_P (bb->global_live_at_end, regno))
|
||
fprintf (file, " %d", regno);
|
||
}
|
||
else
|
||
fprintf (file, " n/a");
|
||
|
||
putc('\n', file);
|
||
}
|
||
|
||
putc('\n', file);
|
||
}
|
||
|
||
static void
|
||
dump_edge_info (file, e, do_succ)
|
||
FILE *file;
|
||
edge e;
|
||
int do_succ;
|
||
{
|
||
basic_block side = (do_succ ? e->dest : e->src);
|
||
|
||
if (side == ENTRY_BLOCK_PTR)
|
||
fputs (" ENTRY", file);
|
||
else if (side == EXIT_BLOCK_PTR)
|
||
fputs (" EXIT", file);
|
||
else
|
||
fprintf (file, " %d", side->index);
|
||
|
||
if (e->flags)
|
||
{
|
||
static char * bitnames[] = {
|
||
"fallthru", "crit", "ab", "abcall", "eh", "fake"
|
||
};
|
||
int comma = 0;
|
||
int i, flags = e->flags;
|
||
|
||
fputc (' ', file);
|
||
fputc ('(', file);
|
||
for (i = 0; flags; i++)
|
||
if (flags & (1 << i))
|
||
{
|
||
flags &= ~(1 << i);
|
||
|
||
if (comma)
|
||
fputc (',', file);
|
||
if (i < (int)(sizeof (bitnames) / sizeof (*bitnames)))
|
||
fputs (bitnames[i], file);
|
||
else
|
||
fprintf (file, "%d", i);
|
||
comma = 1;
|
||
}
|
||
fputc (')', file);
|
||
}
|
||
}
|
||
|
||
|
||
/* Like print_rtl, but also print out live information for the start of each
|
||
basic block. */
|
||
|
||
void
|
||
print_rtl_with_bb (outf, rtx_first)
|
||
FILE *outf;
|
||
rtx rtx_first;
|
||
{
|
||
register rtx tmp_rtx;
|
||
|
||
if (rtx_first == 0)
|
||
fprintf (outf, "(nil)\n");
|
||
else
|
||
{
|
||
int i;
|
||
enum bb_state { NOT_IN_BB, IN_ONE_BB, IN_MULTIPLE_BB };
|
||
int max_uid = get_max_uid ();
|
||
basic_block *start = (basic_block *)
|
||
alloca (max_uid * sizeof (basic_block));
|
||
basic_block *end = (basic_block *)
|
||
alloca (max_uid * sizeof (basic_block));
|
||
enum bb_state *in_bb_p = (enum bb_state *)
|
||
alloca (max_uid * sizeof (enum bb_state));
|
||
|
||
memset (start, 0, max_uid * sizeof (basic_block));
|
||
memset (end, 0, max_uid * sizeof (basic_block));
|
||
memset (in_bb_p, 0, max_uid * sizeof (enum bb_state));
|
||
|
||
for (i = n_basic_blocks - 1; i >= 0; i--)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
rtx x;
|
||
|
||
start[INSN_UID (bb->head)] = bb;
|
||
end[INSN_UID (bb->end)] = bb;
|
||
for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
|
||
{
|
||
enum bb_state state = IN_MULTIPLE_BB;
|
||
if (in_bb_p[INSN_UID(x)] == NOT_IN_BB)
|
||
state = IN_ONE_BB;
|
||
in_bb_p[INSN_UID(x)] = state;
|
||
|
||
if (x == bb->end)
|
||
break;
|
||
}
|
||
}
|
||
|
||
for (tmp_rtx = rtx_first; NULL != tmp_rtx; tmp_rtx = NEXT_INSN (tmp_rtx))
|
||
{
|
||
int did_output;
|
||
basic_block bb;
|
||
|
||
if ((bb = start[INSN_UID (tmp_rtx)]) != NULL)
|
||
{
|
||
fprintf (outf, ";; Start of basic block %d, registers live:",
|
||
bb->index);
|
||
|
||
EXECUTE_IF_SET_IN_REG_SET (bb->global_live_at_start, 0, i,
|
||
{
|
||
fprintf (outf, " %d", i);
|
||
if (i < FIRST_PSEUDO_REGISTER)
|
||
fprintf (outf, " [%s]",
|
||
reg_names[i]);
|
||
});
|
||
putc ('\n', outf);
|
||
}
|
||
|
||
if (in_bb_p[INSN_UID(tmp_rtx)] == NOT_IN_BB
|
||
&& GET_CODE (tmp_rtx) != NOTE
|
||
&& GET_CODE (tmp_rtx) != BARRIER
|
||
&& ! obey_regdecls)
|
||
fprintf (outf, ";; Insn is not within a basic block\n");
|
||
else if (in_bb_p[INSN_UID(tmp_rtx)] == IN_MULTIPLE_BB)
|
||
fprintf (outf, ";; Insn is in multiple basic blocks\n");
|
||
|
||
did_output = print_rtl_single (outf, tmp_rtx);
|
||
|
||
if ((bb = end[INSN_UID (tmp_rtx)]) != NULL)
|
||
fprintf (outf, ";; End of basic block %d\n", bb->index);
|
||
|
||
if (did_output)
|
||
putc ('\n', outf);
|
||
}
|
||
}
|
||
}
|
||
|
||
|
||
/* Integer list support. */
|
||
|
||
/* Allocate a node from list *HEAD_PTR. */
|
||
|
||
static int_list_ptr
|
||
alloc_int_list_node (head_ptr)
|
||
int_list_block **head_ptr;
|
||
{
|
||
struct int_list_block *first_blk = *head_ptr;
|
||
|
||
if (first_blk == NULL || first_blk->nodes_left <= 0)
|
||
{
|
||
first_blk = (struct int_list_block *) xmalloc (sizeof (struct int_list_block));
|
||
first_blk->nodes_left = INT_LIST_NODES_IN_BLK;
|
||
first_blk->next = *head_ptr;
|
||
*head_ptr = first_blk;
|
||
}
|
||
|
||
first_blk->nodes_left--;
|
||
return &first_blk->nodes[first_blk->nodes_left];
|
||
}
|
||
|
||
/* Pointer to head of predecessor/successor block list. */
|
||
static int_list_block *pred_int_list_blocks;
|
||
|
||
/* Add a new node to integer list LIST with value VAL.
|
||
LIST is a pointer to a list object to allow for different implementations.
|
||
If *LIST is initially NULL, the list is empty.
|
||
The caller must not care whether the element is added to the front or
|
||
to the end of the list (to allow for different implementations). */
|
||
|
||
static int_list_ptr
|
||
add_int_list_node (blk_list, list, val)
|
||
int_list_block **blk_list;
|
||
int_list **list;
|
||
int val;
|
||
{
|
||
int_list_ptr p = alloc_int_list_node (blk_list);
|
||
|
||
p->val = val;
|
||
p->next = *list;
|
||
*list = p;
|
||
return p;
|
||
}
|
||
|
||
/* Free the blocks of lists at BLK_LIST. */
|
||
|
||
void
|
||
free_int_list (blk_list)
|
||
int_list_block **blk_list;
|
||
{
|
||
int_list_block *p, *next;
|
||
|
||
for (p = *blk_list; p != NULL; p = next)
|
||
{
|
||
next = p->next;
|
||
free (p);
|
||
}
|
||
|
||
/* Mark list as empty for the next function we compile. */
|
||
*blk_list = NULL;
|
||
}
|
||
|
||
/* Predecessor/successor computation. */
|
||
|
||
/* Mark PRED_BB a precessor of SUCC_BB,
|
||
and conversely SUCC_BB a successor of PRED_BB. */
|
||
|
||
static void
|
||
add_pred_succ (pred_bb, succ_bb, s_preds, s_succs, num_preds, num_succs)
|
||
int pred_bb;
|
||
int succ_bb;
|
||
int_list_ptr *s_preds;
|
||
int_list_ptr *s_succs;
|
||
int *num_preds;
|
||
int *num_succs;
|
||
{
|
||
if (succ_bb != EXIT_BLOCK)
|
||
{
|
||
add_int_list_node (&pred_int_list_blocks, &s_preds[succ_bb], pred_bb);
|
||
num_preds[succ_bb]++;
|
||
}
|
||
if (pred_bb != ENTRY_BLOCK)
|
||
{
|
||
add_int_list_node (&pred_int_list_blocks, &s_succs[pred_bb], succ_bb);
|
||
num_succs[pred_bb]++;
|
||
}
|
||
}
|
||
|
||
/* Convert edge lists into pred/succ lists for backward compatibility. */
|
||
|
||
void
|
||
compute_preds_succs (s_preds, s_succs, num_preds, num_succs)
|
||
int_list_ptr *s_preds;
|
||
int_list_ptr *s_succs;
|
||
int *num_preds;
|
||
int *num_succs;
|
||
{
|
||
int i, n = n_basic_blocks;
|
||
edge e;
|
||
|
||
memset (s_preds, 0, n_basic_blocks * sizeof (int_list_ptr));
|
||
memset (s_succs, 0, n_basic_blocks * sizeof (int_list_ptr));
|
||
memset (num_preds, 0, n_basic_blocks * sizeof (int));
|
||
memset (num_succs, 0, n_basic_blocks * sizeof (int));
|
||
|
||
for (i = 0; i < n; ++i)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
for (e = bb->succ; e ; e = e->succ_next)
|
||
add_pred_succ (i, e->dest->index, s_preds, s_succs,
|
||
num_preds, num_succs);
|
||
}
|
||
|
||
for (e = ENTRY_BLOCK_PTR->succ; e ; e = e->succ_next)
|
||
add_pred_succ (ENTRY_BLOCK, e->dest->index, s_preds, s_succs,
|
||
num_preds, num_succs);
|
||
}
|
||
|
||
void
|
||
dump_bb_data (file, preds, succs, live_info)
|
||
FILE *file;
|
||
int_list_ptr *preds;
|
||
int_list_ptr *succs;
|
||
int live_info;
|
||
{
|
||
int bb;
|
||
int_list_ptr p;
|
||
|
||
fprintf (file, "BB data\n\n");
|
||
for (bb = 0; bb < n_basic_blocks; bb++)
|
||
{
|
||
fprintf (file, "BB %d, start %d, end %d\n", bb,
|
||
INSN_UID (BLOCK_HEAD (bb)), INSN_UID (BLOCK_END (bb)));
|
||
fprintf (file, " preds:");
|
||
for (p = preds[bb]; p != NULL; p = p->next)
|
||
{
|
||
int pred_bb = INT_LIST_VAL (p);
|
||
if (pred_bb == ENTRY_BLOCK)
|
||
fprintf (file, " entry");
|
||
else
|
||
fprintf (file, " %d", pred_bb);
|
||
}
|
||
fprintf (file, "\n");
|
||
fprintf (file, " succs:");
|
||
for (p = succs[bb]; p != NULL; p = p->next)
|
||
{
|
||
int succ_bb = INT_LIST_VAL (p);
|
||
if (succ_bb == EXIT_BLOCK)
|
||
fprintf (file, " exit");
|
||
else
|
||
fprintf (file, " %d", succ_bb);
|
||
}
|
||
if (live_info)
|
||
{
|
||
int regno;
|
||
fprintf (file, "\nRegisters live at start:");
|
||
for (regno = 0; regno < max_regno; regno++)
|
||
if (REGNO_REG_SET_P (BASIC_BLOCK (bb)->global_live_at_start, regno))
|
||
fprintf (file, " %d", regno);
|
||
fprintf (file, "\n");
|
||
}
|
||
fprintf (file, "\n");
|
||
}
|
||
fprintf (file, "\n");
|
||
}
|
||
|
||
/* Free basic block data storage. */
|
||
|
||
void
|
||
free_bb_mem ()
|
||
{
|
||
free_int_list (&pred_int_list_blocks);
|
||
}
|
||
|
||
/* Compute dominator relationships. */
|
||
void
|
||
compute_dominators (dominators, post_dominators, s_preds, s_succs)
|
||
sbitmap *dominators;
|
||
sbitmap *post_dominators;
|
||
int_list_ptr *s_preds;
|
||
int_list_ptr *s_succs;
|
||
{
|
||
int bb, changed, passes;
|
||
sbitmap *temp_bitmap;
|
||
|
||
temp_bitmap = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
|
||
sbitmap_vector_ones (dominators, n_basic_blocks);
|
||
sbitmap_vector_ones (post_dominators, n_basic_blocks);
|
||
sbitmap_vector_zero (temp_bitmap, n_basic_blocks);
|
||
|
||
sbitmap_zero (dominators[0]);
|
||
SET_BIT (dominators[0], 0);
|
||
|
||
sbitmap_zero (post_dominators[n_basic_blocks - 1]);
|
||
SET_BIT (post_dominators[n_basic_blocks - 1], 0);
|
||
|
||
passes = 0;
|
||
changed = 1;
|
||
while (changed)
|
||
{
|
||
changed = 0;
|
||
for (bb = 1; bb < n_basic_blocks; bb++)
|
||
{
|
||
sbitmap_intersect_of_predecessors (temp_bitmap[bb], dominators,
|
||
bb, s_preds);
|
||
SET_BIT (temp_bitmap[bb], bb);
|
||
changed |= sbitmap_a_and_b (dominators[bb],
|
||
dominators[bb],
|
||
temp_bitmap[bb]);
|
||
sbitmap_intersect_of_successors (temp_bitmap[bb], post_dominators,
|
||
bb, s_succs);
|
||
SET_BIT (temp_bitmap[bb], bb);
|
||
changed |= sbitmap_a_and_b (post_dominators[bb],
|
||
post_dominators[bb],
|
||
temp_bitmap[bb]);
|
||
}
|
||
passes++;
|
||
}
|
||
|
||
free (temp_bitmap);
|
||
}
|
||
|
||
/* Given DOMINATORS, compute the immediate dominators into IDOM. */
|
||
|
||
void
|
||
compute_immediate_dominators (idom, dominators)
|
||
int *idom;
|
||
sbitmap *dominators;
|
||
{
|
||
sbitmap *tmp;
|
||
int b;
|
||
|
||
tmp = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
|
||
|
||
/* Begin with tmp(n) = dom(n) - { n }. */
|
||
for (b = n_basic_blocks; --b >= 0; )
|
||
{
|
||
sbitmap_copy (tmp[b], dominators[b]);
|
||
RESET_BIT (tmp[b], b);
|
||
}
|
||
|
||
/* Subtract out all of our dominator's dominators. */
|
||
for (b = n_basic_blocks; --b >= 0; )
|
||
{
|
||
sbitmap tmp_b = tmp[b];
|
||
int s;
|
||
|
||
for (s = n_basic_blocks; --s >= 0; )
|
||
if (TEST_BIT (tmp_b, s))
|
||
sbitmap_difference (tmp_b, tmp_b, tmp[s]);
|
||
}
|
||
|
||
/* Find the one bit set in the bitmap and put it in the output array. */
|
||
for (b = n_basic_blocks; --b >= 0; )
|
||
{
|
||
int t;
|
||
EXECUTE_IF_SET_IN_SBITMAP (tmp[b], 0, t, { idom[b] = t; });
|
||
}
|
||
|
||
sbitmap_vector_free (tmp);
|
||
}
|
||
|
||
/* Count for a single SET rtx, X. */
|
||
|
||
static void
|
||
count_reg_sets_1 (x)
|
||
rtx x;
|
||
{
|
||
register int regno;
|
||
register rtx reg = SET_DEST (x);
|
||
|
||
/* Find the register that's set/clobbered. */
|
||
while (GET_CODE (reg) == SUBREG || GET_CODE (reg) == ZERO_EXTRACT
|
||
|| GET_CODE (reg) == SIGN_EXTRACT
|
||
|| GET_CODE (reg) == STRICT_LOW_PART)
|
||
reg = XEXP (reg, 0);
|
||
|
||
if (GET_CODE (reg) == PARALLEL
|
||
&& GET_MODE (reg) == BLKmode)
|
||
{
|
||
register int i;
|
||
for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
|
||
count_reg_sets_1 (XVECEXP (reg, 0, i));
|
||
return;
|
||
}
|
||
|
||
if (GET_CODE (reg) == REG)
|
||
{
|
||
regno = REGNO (reg);
|
||
if (regno >= FIRST_PSEUDO_REGISTER)
|
||
{
|
||
/* Count (weighted) references, stores, etc. This counts a
|
||
register twice if it is modified, but that is correct. */
|
||
REG_N_SETS (regno)++;
|
||
|
||
REG_N_REFS (regno) += loop_depth;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Increment REG_N_SETS for each SET or CLOBBER found in X; also increment
|
||
REG_N_REFS by the current loop depth for each SET or CLOBBER found. */
|
||
|
||
static void
|
||
count_reg_sets (x)
|
||
rtx x;
|
||
{
|
||
register RTX_CODE code = GET_CODE (x);
|
||
|
||
if (code == SET || code == CLOBBER)
|
||
count_reg_sets_1 (x);
|
||
else if (code == PARALLEL)
|
||
{
|
||
register int i;
|
||
for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
|
||
{
|
||
code = GET_CODE (XVECEXP (x, 0, i));
|
||
if (code == SET || code == CLOBBER)
|
||
count_reg_sets_1 (XVECEXP (x, 0, i));
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Increment REG_N_REFS by the current loop depth each register reference
|
||
found in X. */
|
||
|
||
static void
|
||
count_reg_references (x)
|
||
rtx x;
|
||
{
|
||
register RTX_CODE code;
|
||
|
||
retry:
|
||
code = GET_CODE (x);
|
||
switch (code)
|
||
{
|
||
case LABEL_REF:
|
||
case SYMBOL_REF:
|
||
case CONST_INT:
|
||
case CONST:
|
||
case CONST_DOUBLE:
|
||
case PC:
|
||
case ADDR_VEC:
|
||
case ADDR_DIFF_VEC:
|
||
case ASM_INPUT:
|
||
return;
|
||
|
||
#ifdef HAVE_cc0
|
||
case CC0:
|
||
return;
|
||
#endif
|
||
|
||
case CLOBBER:
|
||
/* If we are clobbering a MEM, mark any registers inside the address
|
||
as being used. */
|
||
if (GET_CODE (XEXP (x, 0)) == MEM)
|
||
count_reg_references (XEXP (XEXP (x, 0), 0));
|
||
return;
|
||
|
||
case SUBREG:
|
||
/* While we're here, optimize this case. */
|
||
x = SUBREG_REG (x);
|
||
|
||
/* In case the SUBREG is not of a register, don't optimize */
|
||
if (GET_CODE (x) != REG)
|
||
{
|
||
count_reg_references (x);
|
||
return;
|
||
}
|
||
|
||
/* ... fall through ... */
|
||
|
||
case REG:
|
||
if (REGNO (x) >= FIRST_PSEUDO_REGISTER)
|
||
REG_N_REFS (REGNO (x)) += loop_depth;
|
||
return;
|
||
|
||
case SET:
|
||
{
|
||
register rtx testreg = SET_DEST (x);
|
||
int mark_dest = 0;
|
||
|
||
/* If storing into MEM, don't show it as being used. But do
|
||
show the address as being used. */
|
||
if (GET_CODE (testreg) == MEM)
|
||
{
|
||
count_reg_references (XEXP (testreg, 0));
|
||
count_reg_references (SET_SRC (x));
|
||
return;
|
||
}
|
||
|
||
/* Storing in STRICT_LOW_PART is like storing in a reg
|
||
in that this SET might be dead, so ignore it in TESTREG.
|
||
but in some other ways it is like using the reg.
|
||
|
||
Storing in a SUBREG or a bit field is like storing the entire
|
||
register in that if the register's value is not used
|
||
then this SET is not needed. */
|
||
while (GET_CODE (testreg) == STRICT_LOW_PART
|
||
|| GET_CODE (testreg) == ZERO_EXTRACT
|
||
|| GET_CODE (testreg) == SIGN_EXTRACT
|
||
|| GET_CODE (testreg) == SUBREG)
|
||
{
|
||
/* Modifying a single register in an alternate mode
|
||
does not use any of the old value. But these other
|
||
ways of storing in a register do use the old value. */
|
||
if (GET_CODE (testreg) == SUBREG
|
||
&& !(REG_SIZE (SUBREG_REG (testreg)) > REG_SIZE (testreg)))
|
||
;
|
||
else
|
||
mark_dest = 1;
|
||
|
||
testreg = XEXP (testreg, 0);
|
||
}
|
||
|
||
/* If this is a store into a register,
|
||
recursively scan the value being stored. */
|
||
|
||
if ((GET_CODE (testreg) == PARALLEL
|
||
&& GET_MODE (testreg) == BLKmode)
|
||
|| GET_CODE (testreg) == REG)
|
||
{
|
||
count_reg_references (SET_SRC (x));
|
||
if (mark_dest)
|
||
count_reg_references (SET_DEST (x));
|
||
return;
|
||
}
|
||
}
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* Recursively scan the operands of this expression. */
|
||
|
||
{
|
||
register char *fmt = GET_RTX_FORMAT (code);
|
||
register int i;
|
||
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
{
|
||
/* Tail recursive case: save a function call level. */
|
||
if (i == 0)
|
||
{
|
||
x = XEXP (x, 0);
|
||
goto retry;
|
||
}
|
||
count_reg_references (XEXP (x, i));
|
||
}
|
||
else if (fmt[i] == 'E')
|
||
{
|
||
register int j;
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
count_reg_references (XVECEXP (x, i, j));
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Recompute register set/reference counts immediately prior to register
|
||
allocation.
|
||
|
||
This avoids problems with set/reference counts changing to/from values
|
||
which have special meanings to the register allocators.
|
||
|
||
Additionally, the reference counts are the primary component used by the
|
||
register allocators to prioritize pseudos for allocation to hard regs.
|
||
More accurate reference counts generally lead to better register allocation.
|
||
|
||
F is the first insn to be scanned.
|
||
LOOP_STEP denotes how much loop_depth should be incremented per
|
||
loop nesting level in order to increase the ref count more for references
|
||
in a loop.
|
||
|
||
It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
|
||
possibly other information which is used by the register allocators. */
|
||
|
||
void
|
||
recompute_reg_usage (f, loop_step)
|
||
rtx f;
|
||
int loop_step;
|
||
{
|
||
rtx insn;
|
||
int i, max_reg;
|
||
|
||
/* Clear out the old data. */
|
||
max_reg = max_reg_num ();
|
||
for (i = FIRST_PSEUDO_REGISTER; i < max_reg; i++)
|
||
{
|
||
REG_N_SETS (i) = 0;
|
||
REG_N_REFS (i) = 0;
|
||
}
|
||
|
||
/* Scan each insn in the chain and count how many times each register is
|
||
set/used. */
|
||
loop_depth = 1;
|
||
for (insn = f; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
/* Keep track of loop depth. */
|
||
if (GET_CODE (insn) == NOTE)
|
||
{
|
||
/* Look for loop boundaries. */
|
||
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
|
||
loop_depth -= loop_step;
|
||
else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
|
||
loop_depth += loop_step;
|
||
|
||
/* If we have LOOP_DEPTH == 0, there has been a bookkeeping error.
|
||
Abort now rather than setting register status incorrectly. */
|
||
if (loop_depth == 0)
|
||
abort ();
|
||
}
|
||
else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
|
||
{
|
||
rtx links;
|
||
|
||
/* This call will increment REG_N_SETS for each SET or CLOBBER
|
||
of a register in INSN. It will also increment REG_N_REFS
|
||
by the loop depth for each set of a register in INSN. */
|
||
count_reg_sets (PATTERN (insn));
|
||
|
||
/* count_reg_sets does not detect autoincrement address modes, so
|
||
detect them here by looking at the notes attached to INSN. */
|
||
for (links = REG_NOTES (insn); links; links = XEXP (links, 1))
|
||
{
|
||
if (REG_NOTE_KIND (links) == REG_INC)
|
||
/* Count (weighted) references, stores, etc. This counts a
|
||
register twice if it is modified, but that is correct. */
|
||
REG_N_SETS (REGNO (XEXP (links, 0)))++;
|
||
}
|
||
|
||
/* This call will increment REG_N_REFS by the current loop depth for
|
||
each reference to a register in INSN. */
|
||
count_reg_references (PATTERN (insn));
|
||
|
||
/* count_reg_references will not include counts for arguments to
|
||
function calls, so detect them here by examining the
|
||
CALL_INSN_FUNCTION_USAGE data. */
|
||
if (GET_CODE (insn) == CALL_INSN)
|
||
{
|
||
rtx note;
|
||
|
||
for (note = CALL_INSN_FUNCTION_USAGE (insn);
|
||
note;
|
||
note = XEXP (note, 1))
|
||
if (GET_CODE (XEXP (note, 0)) == USE)
|
||
count_reg_references (SET_DEST (XEXP (note, 0)));
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Record INSN's block as BB. */
|
||
|
||
void
|
||
set_block_for_insn (insn, bb)
|
||
rtx insn;
|
||
basic_block bb;
|
||
{
|
||
size_t uid = INSN_UID (insn);
|
||
if (uid >= basic_block_for_insn->num_elements)
|
||
{
|
||
int new_size;
|
||
|
||
/* Add one-eighth the size so we don't keep calling xrealloc. */
|
||
new_size = uid + (uid + 7) / 8;
|
||
|
||
VARRAY_GROW (basic_block_for_insn, new_size);
|
||
}
|
||
VARRAY_BB (basic_block_for_insn, uid) = bb;
|
||
}
|
||
|
||
/* Record INSN's block number as BB. */
|
||
/* ??? This has got to go. */
|
||
|
||
void
|
||
set_block_num (insn, bb)
|
||
rtx insn;
|
||
int bb;
|
||
{
|
||
set_block_for_insn (insn, BASIC_BLOCK (bb));
|
||
}
|
||
|
||
/* Verify the CFG consistency. This function check some CFG invariants and
|
||
aborts when something is wrong. Hope that this function will help to
|
||
convert many optimization passes to preserve CFG consistent.
|
||
|
||
Currently it does following checks:
|
||
|
||
- test head/end pointers
|
||
- overlapping of basic blocks
|
||
- edge list corectness
|
||
- headers of basic blocks (the NOTE_INSN_BASIC_BLOCK note)
|
||
- tails of basic blocks (ensure that boundary is necesary)
|
||
- scans body of the basic block for JUMP_INSN, CODE_LABEL
|
||
and NOTE_INSN_BASIC_BLOCK
|
||
- check that all insns are in the basic blocks
|
||
(except the switch handling code, barriers and notes)
|
||
|
||
In future it can be extended check a lot of other stuff as well
|
||
(reachability of basic blocks, life information, etc. etc.). */
|
||
|
||
void
|
||
verify_flow_info ()
|
||
{
|
||
const int max_uid = get_max_uid ();
|
||
const rtx rtx_first = get_insns ();
|
||
basic_block *bb_info;
|
||
rtx x;
|
||
int i;
|
||
|
||
bb_info = (basic_block *) alloca (max_uid * sizeof (basic_block));
|
||
memset (bb_info, 0, max_uid * sizeof (basic_block));
|
||
|
||
/* First pass check head/end pointers and set bb_info array used by
|
||
later passes. */
|
||
for (i = n_basic_blocks - 1; i >= 0; i--)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
/* Check the head pointer and make sure that it is pointing into
|
||
insn list. */
|
||
for (x = rtx_first; x != NULL_RTX; x = NEXT_INSN (x))
|
||
if (x == bb->head)
|
||
break;
|
||
if (!x)
|
||
{
|
||
fatal ("verify_flow_info: Head insn %d for block %d not found in the insn stream.\n",
|
||
INSN_UID (bb->head), bb->index);
|
||
}
|
||
|
||
/* Check the end pointer and make sure that it is pointing into
|
||
insn list. */
|
||
for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
|
||
{
|
||
if (bb_info[INSN_UID (x)] != NULL)
|
||
{
|
||
fatal ("verify_flow_info: Insn %d is in multiple basic blocks (%d and %d)",
|
||
INSN_UID (x), bb->index, bb_info[INSN_UID (x)]->index);
|
||
}
|
||
bb_info[INSN_UID (x)] = bb;
|
||
|
||
if (x == bb->end)
|
||
break;
|
||
}
|
||
if (!x)
|
||
{
|
||
fatal ("verify_flow_info: End insn %d for block %d not found in the insn stream.\n",
|
||
INSN_UID (bb->end), bb->index);
|
||
}
|
||
}
|
||
|
||
/* Now check the basic blocks (boundaries etc.) */
|
||
for (i = n_basic_blocks - 1; i >= 0; i--)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
/* Check corectness of edge lists */
|
||
edge e;
|
||
|
||
e = bb->succ;
|
||
while (e)
|
||
{
|
||
if (e->src != bb)
|
||
{
|
||
fprintf (stderr, "verify_flow_info: Basic block %d succ edge is corrupted\n",
|
||
bb->index);
|
||
fprintf (stderr, "Predecessor: ");
|
||
dump_edge_info (stderr, e, 0);
|
||
fprintf (stderr, "\nSuccessor: ");
|
||
dump_edge_info (stderr, e, 1);
|
||
fflush (stderr);
|
||
abort ();
|
||
}
|
||
if (e->dest != EXIT_BLOCK_PTR)
|
||
{
|
||
edge e2 = e->dest->pred;
|
||
while (e2 && e2 != e)
|
||
e2 = e2->pred_next;
|
||
if (!e2)
|
||
{
|
||
fatal ("verify_flow_info: Basic block %i edge lists are corrupted\n",
|
||
bb->index);
|
||
}
|
||
}
|
||
e = e->succ_next;
|
||
}
|
||
|
||
e = bb->pred;
|
||
while (e)
|
||
{
|
||
if (e->dest != bb)
|
||
{
|
||
fprintf (stderr, "verify_flow_info: Basic block %d pred edge is corrupted\n",
|
||
bb->index);
|
||
fprintf (stderr, "Predecessor: ");
|
||
dump_edge_info (stderr, e, 0);
|
||
fprintf (stderr, "\nSuccessor: ");
|
||
dump_edge_info (stderr, e, 1);
|
||
fflush (stderr);
|
||
abort ();
|
||
}
|
||
if (e->src != ENTRY_BLOCK_PTR)
|
||
{
|
||
edge e2 = e->src->succ;
|
||
while (e2 && e2 != e)
|
||
e2 = e2->succ_next;
|
||
if (!e2)
|
||
{
|
||
fatal ("verify_flow_info: Basic block %i edge lists are corrupted\n",
|
||
bb->index);
|
||
}
|
||
}
|
||
e = e->pred_next;
|
||
}
|
||
|
||
/* OK pointers are correct. Now check the header of basic
|
||
block. It ought to contain optional CODE_LABEL followed
|
||
by NOTE_BASIC_BLOCK. */
|
||
x = bb->head;
|
||
if (GET_CODE (x) == CODE_LABEL)
|
||
{
|
||
if (bb->end == x)
|
||
{
|
||
fatal ("verify_flow_info: Basic block contains only CODE_LABEL and no NOTE_INSN_BASIC_BLOCK note\n");
|
||
}
|
||
x = NEXT_INSN (x);
|
||
}
|
||
if (GET_CODE (x) != NOTE
|
||
|| NOTE_LINE_NUMBER (x) != NOTE_INSN_BASIC_BLOCK
|
||
|| NOTE_BASIC_BLOCK (x) != bb)
|
||
{
|
||
fatal ("verify_flow_info: NOTE_INSN_BASIC_BLOCK is missing for block %d\n",
|
||
bb->index);
|
||
}
|
||
|
||
if (bb->end == x)
|
||
{
|
||
/* Do checks for empty blocks here */
|
||
}
|
||
else
|
||
{
|
||
x = NEXT_INSN (x);
|
||
while (x)
|
||
{
|
||
if (GET_CODE (x) == NOTE
|
||
&& NOTE_LINE_NUMBER (x) == NOTE_INSN_BASIC_BLOCK)
|
||
{
|
||
fatal ("verify_flow_info: NOTE_INSN_BASIC_BLOCK %d in the middle of basic block %d\n",
|
||
INSN_UID (x), bb->index);
|
||
}
|
||
|
||
if (x == bb->end)
|
||
break;
|
||
|
||
if (GET_CODE (x) == JUMP_INSN
|
||
|| GET_CODE (x) == CODE_LABEL
|
||
|| GET_CODE (x) == BARRIER)
|
||
{
|
||
fatal_insn ("verify_flow_info: Incorrect insn in the middle of basic block %d\n",
|
||
x, bb->index);
|
||
}
|
||
|
||
x = NEXT_INSN (x);
|
||
}
|
||
}
|
||
}
|
||
|
||
x = rtx_first;
|
||
while (x)
|
||
{
|
||
if (!bb_info[INSN_UID (x)])
|
||
{
|
||
switch (GET_CODE (x))
|
||
{
|
||
case BARRIER:
|
||
case NOTE:
|
||
break;
|
||
|
||
case CODE_LABEL:
|
||
/* An addr_vec is placed outside any block block. */
|
||
if (NEXT_INSN (x)
|
||
&& GET_CODE (NEXT_INSN (x)) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_DIFF_VEC
|
||
|| GET_CODE (PATTERN (NEXT_INSN (x))) == ADDR_VEC))
|
||
{
|
||
x = NEXT_INSN (x);
|
||
}
|
||
|
||
/* But in any case, non-deletable labels can appear anywhere. */
|
||
break;
|
||
|
||
default:
|
||
fatal_insn ("verify_flow_info: Insn outside basic block\n", x);
|
||
}
|
||
}
|
||
|
||
x = NEXT_INSN (x);
|
||
}
|
||
}
|