4266 lines
125 KiB
C
4266 lines
125 KiB
C
/* Data flow analysis for GNU compiler.
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Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
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1999, 2000, 2001 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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 GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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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_CROSSED 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 "tree.h"
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#include "rtl.h"
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#include "tm_p.h"
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#include "hard-reg-set.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 "flags.h"
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#include "output.h"
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#include "function.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 "expr.h"
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#include "ssa.h"
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#include "timevar.h"
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#include "obstack.h"
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#include "splay-tree.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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#ifndef HAVE_epilogue
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#define HAVE_epilogue 0
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#endif
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#ifndef HAVE_prologue
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#define HAVE_prologue 0
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#endif
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#ifndef HAVE_sibcall_epilogue
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#define HAVE_sibcall_epilogue 0
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#endif
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#ifndef LOCAL_REGNO
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#define LOCAL_REGNO(REGNO) 0
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#endif
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#ifndef EPILOGUE_USES
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#define EPILOGUE_USES(REGNO) 0
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#endif
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#ifdef HAVE_conditional_execution
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#ifndef REVERSE_CONDEXEC_PREDICATES_P
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#define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
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#endif
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#endif
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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 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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/* Callback that determines if it's ok for a function to have no
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noreturn attribute. */
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int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
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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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/* Holds information for tracking conditional register life information. */
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struct reg_cond_life_info
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{
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/* A boolean expression of conditions under which a register is dead. */
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rtx condition;
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/* Conditions under which a register is dead at the basic block end. */
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rtx orig_condition;
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/* A boolean expression of conditions under which a register has been
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stored into. */
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rtx stores;
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/* ??? Could store mask of bytes that are dead, so that we could finally
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track lifetimes of multi-word registers accessed via subregs. */
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};
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/* For use in communicating between propagate_block and its subroutines.
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Holds all information needed to compute life and def-use information. */
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struct propagate_block_info
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{
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/* The basic block we're considering. */
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basic_block bb;
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/* Bit N is set if register N is conditionally or unconditionally live. */
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regset reg_live;
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/* Bit N is set if register N is set this insn. */
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regset new_set;
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/* Element N is the next insn that uses (hard or pseudo) register N
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within the current basic block; or zero, if there is no such insn. */
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rtx *reg_next_use;
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/* Contains a list of all the MEMs we are tracking for dead store
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elimination. */
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rtx mem_set_list;
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/* If non-null, record the set of registers set unconditionally in the
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basic block. */
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regset local_set;
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/* If non-null, record the set of registers set conditionally in the
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basic block. */
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regset cond_local_set;
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#ifdef HAVE_conditional_execution
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/* Indexed by register number, holds a reg_cond_life_info for each
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register that is not unconditionally live or dead. */
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splay_tree reg_cond_dead;
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/* Bit N is set if register N is in an expression in reg_cond_dead. */
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regset reg_cond_reg;
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#endif
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/* The length of mem_set_list. */
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int mem_set_list_len;
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/* Non-zero if the value of CC0 is live. */
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int cc0_live;
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/* Flags controling the set of information propagate_block collects. */
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int flags;
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};
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/* Maximum length of pbi->mem_set_list before we start dropping
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new elements on the floor. */
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#define MAX_MEM_SET_LIST_LEN 100
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/* Forward declarations */
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static int verify_wide_reg_1 PARAMS ((rtx *, void *));
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static void verify_wide_reg PARAMS ((int, basic_block));
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static void verify_local_live_at_start PARAMS ((regset, basic_block));
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static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
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static void notice_stack_pointer_modification PARAMS ((rtx));
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static void mark_reg PARAMS ((rtx, void *));
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static void mark_regs_live_at_end PARAMS ((regset));
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static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
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static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
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static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
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static rtx propagate_block_delete_libcall PARAMS ((rtx, rtx));
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static int insn_dead_p PARAMS ((struct propagate_block_info *,
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rtx, int, rtx));
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static int libcall_dead_p PARAMS ((struct propagate_block_info *,
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rtx, rtx));
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static void mark_set_regs PARAMS ((struct propagate_block_info *,
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rtx, rtx));
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static void mark_set_1 PARAMS ((struct propagate_block_info *,
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enum rtx_code, rtx, rtx,
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rtx, int));
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static int find_regno_partial PARAMS ((rtx *, void *));
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#ifdef HAVE_conditional_execution
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static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
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int, rtx));
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static void free_reg_cond_life_info PARAMS ((splay_tree_value));
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static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
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static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
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int));
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static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
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static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
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static rtx not_reg_cond PARAMS ((rtx));
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static rtx and_reg_cond PARAMS ((rtx, rtx, int));
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#endif
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#ifdef AUTO_INC_DEC
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static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
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rtx, rtx, rtx, rtx, rtx));
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static void find_auto_inc PARAMS ((struct propagate_block_info *,
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rtx, rtx));
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static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
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rtx));
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static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
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#endif
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static void mark_used_reg PARAMS ((struct propagate_block_info *,
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rtx, rtx, rtx));
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static void mark_used_regs PARAMS ((struct propagate_block_info *,
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rtx, rtx, rtx));
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void dump_flow_info PARAMS ((FILE *));
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void debug_flow_info PARAMS ((void));
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static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
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rtx));
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static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
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rtx));
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static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
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rtx));
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static void delete_dead_jumptables PARAMS ((void));
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static void clear_log_links PARAMS ((sbitmap));
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void
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check_function_return_warnings ()
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{
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if (warn_missing_noreturn
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&& !TREE_THIS_VOLATILE (cfun->decl)
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&& EXIT_BLOCK_PTR->pred == NULL
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&& (lang_missing_noreturn_ok_p
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&& !lang_missing_noreturn_ok_p (cfun->decl)))
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warning ("function might be possible candidate for attribute `noreturn'");
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/* If we have a path to EXIT, then we do return. */
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if (TREE_THIS_VOLATILE (cfun->decl)
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&& EXIT_BLOCK_PTR->pred != NULL)
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warning ("`noreturn' function does return");
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/* If the clobber_return_insn appears in some basic block, then we
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do reach the end without returning a value. */
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else if (warn_return_type
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&& cfun->x_clobber_return_insn != NULL
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&& EXIT_BLOCK_PTR->pred != NULL)
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{
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int max_uid = get_max_uid ();
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/* If clobber_return_insn was excised by jump1, then renumber_insns
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can make max_uid smaller than the number still recorded in our rtx.
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That's fine, since this is a quick way of verifying that the insn
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is no longer in the chain. */
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if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
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{
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/* Recompute insn->block mapping, since the initial mapping is
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set before we delete unreachable blocks. */
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if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
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warning ("control reaches end of non-void function");
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}
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}
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}
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/* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
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note associated with the BLOCK. */
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rtx
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first_insn_after_basic_block_note (block)
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basic_block block;
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{
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rtx insn;
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/* Get the first instruction in the block. */
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insn = block->head;
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if (insn == NULL_RTX)
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return NULL_RTX;
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if (GET_CODE (insn) == CODE_LABEL)
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insn = NEXT_INSN (insn);
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if (!NOTE_INSN_BASIC_BLOCK_P (insn))
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abort ();
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||
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return NEXT_INSN (insn);
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}
|
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|
||
/* Perform data flow analysis.
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||
F is the first insn of the function; FLAGS is a set of PROP_* flags
|
||
to be used in accumulating flow info. */
|
||
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void
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life_analysis (f, file, flags)
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rtx f;
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FILE *file;
|
||
int flags;
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{
|
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#ifdef ELIMINABLE_REGS
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int i;
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static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
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||
#endif
|
||
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||
/* Record which registers will be eliminated. We use this in
|
||
mark_used_regs. */
|
||
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||
CLEAR_HARD_REG_SET (elim_reg_set);
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||
|
||
#ifdef ELIMINABLE_REGS
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for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
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SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
|
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#else
|
||
SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
|
||
#endif
|
||
|
||
if (! optimize)
|
||
flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
|
||
|
||
/* The post-reload life analysis have (on a global basis) the same
|
||
registers live as was computed by reload itself. elimination
|
||
Otherwise offsets and such may be incorrect.
|
||
|
||
Reload will make some registers as live even though they do not
|
||
appear in the rtl.
|
||
|
||
We don't want to create new auto-incs after reload, since they
|
||
are unlikely to be useful and can cause problems with shared
|
||
stack slots. */
|
||
if (reload_completed)
|
||
flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
|
||
|
||
/* We want alias analysis information for local dead store elimination. */
|
||
if (optimize && (flags & PROP_SCAN_DEAD_CODE))
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||
init_alias_analysis ();
|
||
|
||
/* Always remove no-op moves. Do this before other processing so
|
||
that we don't have to keep re-scanning them. */
|
||
delete_noop_moves (f);
|
||
purge_all_dead_edges (false);
|
||
|
||
/* Some targets can emit simpler epilogues if they know that sp was
|
||
not ever modified during the function. After reload, of course,
|
||
we've already emitted the epilogue so there's no sense searching. */
|
||
if (! reload_completed)
|
||
notice_stack_pointer_modification (f);
|
||
|
||
/* Allocate and zero out data structures that will record the
|
||
data from lifetime analysis. */
|
||
allocate_reg_life_data ();
|
||
allocate_bb_life_data ();
|
||
|
||
/* Find the set of registers live on function exit. */
|
||
mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
|
||
|
||
/* "Update" life info from zero. It'd be nice to begin the
|
||
relaxation with just the exit and noreturn blocks, but that set
|
||
is not immediately handy. */
|
||
|
||
if (flags & PROP_REG_INFO)
|
||
memset (regs_ever_live, 0, sizeof (regs_ever_live));
|
||
update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
|
||
|
||
/* Clean up. */
|
||
if (optimize && (flags & PROP_SCAN_DEAD_CODE))
|
||
end_alias_analysis ();
|
||
|
||
if (file)
|
||
dump_flow_info (file);
|
||
|
||
free_basic_block_vars (1);
|
||
|
||
#ifdef ENABLE_CHECKING
|
||
{
|
||
rtx insn;
|
||
|
||
/* Search for any REG_LABEL notes which reference deleted labels. */
|
||
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
|
||
{
|
||
rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
|
||
|
||
if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
|
||
abort ();
|
||
}
|
||
}
|
||
#endif
|
||
/* Removing dead insns should've made jumptables really dead. */
|
||
delete_dead_jumptables ();
|
||
}
|
||
|
||
/* A subroutine of verify_wide_reg, called through for_each_rtx.
|
||
Search for REGNO. If found, return 2 if it is not wider than
|
||
word_mode. */
|
||
|
||
static int
|
||
verify_wide_reg_1 (px, pregno)
|
||
rtx *px;
|
||
void *pregno;
|
||
{
|
||
rtx x = *px;
|
||
unsigned int regno = *(int *) pregno;
|
||
|
||
if (GET_CODE (x) == REG && REGNO (x) == regno)
|
||
{
|
||
if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
|
||
return 2;
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* A subroutine of verify_local_live_at_start. Search through insns
|
||
of BB looking for register REGNO. */
|
||
|
||
static void
|
||
verify_wide_reg (regno, bb)
|
||
int regno;
|
||
basic_block bb;
|
||
{
|
||
rtx head = bb->head, end = bb->end;
|
||
|
||
while (1)
|
||
{
|
||
if (INSN_P (head))
|
||
{
|
||
int r = for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no);
|
||
if (r == 1)
|
||
return;
|
||
if (r == 2)
|
||
break;
|
||
}
|
||
if (head == end)
|
||
break;
|
||
head = NEXT_INSN (head);
|
||
}
|
||
|
||
if (rtl_dump_file)
|
||
{
|
||
fprintf (rtl_dump_file, "Register %d died unexpectedly.\n", regno);
|
||
dump_bb (bb, rtl_dump_file);
|
||
}
|
||
abort ();
|
||
}
|
||
|
||
/* A subroutine of update_life_info. Verify that there are no untoward
|
||
changes in live_at_start during a local update. */
|
||
|
||
static void
|
||
verify_local_live_at_start (new_live_at_start, bb)
|
||
regset new_live_at_start;
|
||
basic_block bb;
|
||
{
|
||
if (reload_completed)
|
||
{
|
||
/* After reload, there are no pseudos, nor subregs of multi-word
|
||
registers. The regsets should exactly match. */
|
||
if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
|
||
{
|
||
if (rtl_dump_file)
|
||
{
|
||
fprintf (rtl_dump_file,
|
||
"live_at_start mismatch in bb %d, aborting\nNew:\n",
|
||
bb->index);
|
||
debug_bitmap_file (rtl_dump_file, new_live_at_start);
|
||
fputs ("Old:\n", rtl_dump_file);
|
||
dump_bb (bb, rtl_dump_file);
|
||
}
|
||
abort ();
|
||
}
|
||
}
|
||
else
|
||
{
|
||
int i;
|
||
|
||
/* Find the set of changed registers. */
|
||
XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
|
||
|
||
EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
|
||
{
|
||
/* No registers should die. */
|
||
if (REGNO_REG_SET_P (bb->global_live_at_start, i))
|
||
{
|
||
if (rtl_dump_file)
|
||
{
|
||
fprintf (rtl_dump_file,
|
||
"Register %d died unexpectedly.\n", i);
|
||
dump_bb (bb, rtl_dump_file);
|
||
}
|
||
abort ();
|
||
}
|
||
|
||
/* Verify that the now-live register is wider than word_mode. */
|
||
verify_wide_reg (i, bb);
|
||
});
|
||
}
|
||
}
|
||
|
||
/* Updates life information starting with the basic blocks set in BLOCKS.
|
||
If BLOCKS is null, consider it to be the universal set.
|
||
|
||
If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
|
||
we are only expecting local modifications to basic blocks. If we find
|
||
extra registers live at the beginning of a block, then we either killed
|
||
useful data, or we have a broken split that wants data not provided.
|
||
If we find registers removed from live_at_start, that means we have
|
||
a broken peephole that is killing a register it shouldn't.
|
||
|
||
??? This is not true in one situation -- when a pre-reload splitter
|
||
generates subregs of a multi-word pseudo, current life analysis will
|
||
lose the kill. So we _can_ have a pseudo go live. How irritating.
|
||
|
||
Including PROP_REG_INFO does not properly refresh regs_ever_live
|
||
unless the caller resets it to zero. */
|
||
|
||
void
|
||
update_life_info (blocks, extent, prop_flags)
|
||
sbitmap blocks;
|
||
enum update_life_extent extent;
|
||
int prop_flags;
|
||
{
|
||
regset tmp;
|
||
regset_head tmp_head;
|
||
int i;
|
||
|
||
tmp = INITIALIZE_REG_SET (tmp_head);
|
||
|
||
timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
|
||
? TV_LIFE_UPDATE : TV_LIFE);
|
||
|
||
/* Changes to the CFG are only allowed when
|
||
doing a global update for the entire CFG. */
|
||
if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
|
||
&& (extent == UPDATE_LIFE_LOCAL || blocks))
|
||
abort ();
|
||
|
||
/* Clear log links in case we are asked to (re)compute them. */
|
||
if (prop_flags & PROP_LOG_LINKS)
|
||
clear_log_links (blocks);
|
||
|
||
/* For a global update, we go through the relaxation process again. */
|
||
if (extent != UPDATE_LIFE_LOCAL)
|
||
{
|
||
for ( ; ; )
|
||
{
|
||
int changed = 0;
|
||
|
||
calculate_global_regs_live (blocks, blocks,
|
||
prop_flags & (PROP_SCAN_DEAD_CODE
|
||
| PROP_ALLOW_CFG_CHANGES));
|
||
|
||
if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
|
||
!= (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
|
||
break;
|
||
|
||
/* Removing dead code may allow the CFG to be simplified which
|
||
in turn may allow for further dead code detection / removal. */
|
||
for (i = n_basic_blocks - 1; i >= 0; --i)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
COPY_REG_SET (tmp, bb->global_live_at_end);
|
||
changed |= propagate_block (bb, tmp, NULL, NULL,
|
||
prop_flags & (PROP_SCAN_DEAD_CODE
|
||
| PROP_KILL_DEAD_CODE));
|
||
}
|
||
|
||
if (! changed || ! cleanup_cfg (CLEANUP_EXPENSIVE))
|
||
break;
|
||
}
|
||
|
||
/* If asked, remove notes from the blocks we'll update. */
|
||
if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
|
||
count_or_remove_death_notes (blocks, 1);
|
||
}
|
||
|
||
if (blocks)
|
||
{
|
||
EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
COPY_REG_SET (tmp, bb->global_live_at_end);
|
||
propagate_block (bb, tmp, NULL, NULL, prop_flags);
|
||
|
||
if (extent == UPDATE_LIFE_LOCAL)
|
||
verify_local_live_at_start (tmp, bb);
|
||
});
|
||
}
|
||
else
|
||
{
|
||
for (i = n_basic_blocks - 1; i >= 0; --i)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
COPY_REG_SET (tmp, bb->global_live_at_end);
|
||
propagate_block (bb, tmp, NULL, NULL, prop_flags);
|
||
|
||
if (extent == UPDATE_LIFE_LOCAL)
|
||
verify_local_live_at_start (tmp, bb);
|
||
}
|
||
}
|
||
|
||
FREE_REG_SET (tmp);
|
||
|
||
if (prop_flags & PROP_REG_INFO)
|
||
{
|
||
/* 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. */
|
||
EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
|
||
FIRST_PSEUDO_REGISTER, i,
|
||
{ REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
|
||
|
||
/* 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) = REG_BLOCK_UNKNOWN;
|
||
}
|
||
});
|
||
}
|
||
timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
|
||
? TV_LIFE_UPDATE : TV_LIFE);
|
||
}
|
||
|
||
/* 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 (! keep_head_end_p)
|
||
{
|
||
if (basic_block_info)
|
||
{
|
||
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;
|
||
}
|
||
}
|
||
|
||
/* Delete any insns that copy a register to itself. */
|
||
|
||
void
|
||
delete_noop_moves (f)
|
||
rtx f ATTRIBUTE_UNUSED;
|
||
{
|
||
int i;
|
||
rtx insn, next;
|
||
basic_block bb;
|
||
|
||
for (i = 0; i < n_basic_blocks; i++)
|
||
{
|
||
bb = BASIC_BLOCK (i);
|
||
for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
|
||
{
|
||
next = NEXT_INSN (insn);
|
||
if (INSN_P (insn) && noop_move_p (insn))
|
||
{
|
||
rtx note;
|
||
|
||
/* If we're about to remove the first insn of a libcall
|
||
then move the libcall note to the next real insn and
|
||
update the retval note. */
|
||
if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
|
||
&& XEXP (note, 0) != insn)
|
||
{
|
||
rtx new_libcall_insn = next_real_insn (insn);
|
||
rtx retval_note = find_reg_note (XEXP (note, 0),
|
||
REG_RETVAL, NULL_RTX);
|
||
REG_NOTES (new_libcall_insn)
|
||
= gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
|
||
REG_NOTES (new_libcall_insn));
|
||
XEXP (retval_note, 0) = new_libcall_insn;
|
||
}
|
||
|
||
/* Do not call delete_insn here since that may change
|
||
the basic block boundaries which upsets some callers. */
|
||
PUT_CODE (insn, NOTE);
|
||
NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
|
||
NOTE_SOURCE_FILE (insn) = 0;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Delete any jump tables never referenced. We can't delete them at the
|
||
time of removing tablejump insn as they are referenced by the preceding
|
||
insns computing the destination, so we delay deleting and garbagecollect
|
||
them once life information is computed. */
|
||
static void
|
||
delete_dead_jumptables ()
|
||
{
|
||
rtx insn, next;
|
||
for (insn = get_insns (); insn; insn = next)
|
||
{
|
||
next = NEXT_INSN (insn);
|
||
if (GET_CODE (insn) == CODE_LABEL
|
||
&& LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
|
||
&& GET_CODE (next) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (next)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
|
||
{
|
||
if (rtl_dump_file)
|
||
fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
|
||
delete_insn (NEXT_INSN (insn));
|
||
delete_insn (insn);
|
||
next = NEXT_INSN (next);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Determine if the stack pointer is constant over the life of the function.
|
||
Only useful before prologues have been emitted. */
|
||
|
||
static void
|
||
notice_stack_pointer_modification_1 (x, pat, data)
|
||
rtx x;
|
||
rtx pat ATTRIBUTE_UNUSED;
|
||
void *data 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_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
|
||
&& XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
|
||
current_function_sp_is_unchanging = 0;
|
||
}
|
||
|
||
static void
|
||
notice_stack_pointer_modification (f)
|
||
rtx f;
|
||
{
|
||
rtx insn;
|
||
|
||
/* Assume that the stack pointer is unchanging if alloca hasn't
|
||
been used. */
|
||
current_function_sp_is_unchanging = !current_function_calls_alloca;
|
||
if (! current_function_sp_is_unchanging)
|
||
return;
|
||
|
||
for (insn = f; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
if (INSN_P (insn))
|
||
{
|
||
/* Check if insn modifies the stack pointer. */
|
||
note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
|
||
NULL);
|
||
if (! current_function_sp_is_unchanging)
|
||
return;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Mark a register in SET. Hard registers in large modes get all
|
||
of their component registers set as well. */
|
||
|
||
static void
|
||
mark_reg (reg, xset)
|
||
rtx reg;
|
||
void *xset;
|
||
{
|
||
regset set = (regset) xset;
|
||
int regno = REGNO (reg);
|
||
|
||
if (GET_MODE (reg) == BLKmode)
|
||
abort ();
|
||
|
||
SET_REGNO_REG_SET (set, regno);
|
||
if (regno < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
|
||
while (--n > 0)
|
||
SET_REGNO_REG_SET (set, regno + n);
|
||
}
|
||
}
|
||
|
||
/* 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;
|
||
{
|
||
unsigned int i;
|
||
|
||
/* If exiting needs the right stack value, consider the stack pointer
|
||
live at the end of the function. */
|
||
if ((HAVE_epilogue && reload_completed)
|
||
|| ! 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. */
|
||
if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
|
||
SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
|
||
#endif
|
||
}
|
||
|
||
#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
|
||
/* Many architectures have a GP register even without flag_pic.
|
||
Assume the pic register is not in use, or will be handled by
|
||
other means, if it is not fixed. */
|
||
if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
|
||
&& fixed_regs[PIC_OFFSET_TABLE_REGNUM])
|
||
SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_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] || EPILOGUE_USES (i))
|
||
SET_REGNO_REG_SET (set, i);
|
||
|
||
if (HAVE_epilogue && reload_completed)
|
||
{
|
||
/* Mark all call-saved registers that we actually used. */
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (regs_ever_live[i] && ! LOCAL_REGNO (i)
|
||
&& ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
|
||
SET_REGNO_REG_SET (set, i);
|
||
}
|
||
|
||
#ifdef EH_RETURN_DATA_REGNO
|
||
/* Mark the registers that will contain data for the handler. */
|
||
if (reload_completed && current_function_calls_eh_return)
|
||
for (i = 0; ; ++i)
|
||
{
|
||
unsigned regno = EH_RETURN_DATA_REGNO(i);
|
||
if (regno == INVALID_REGNUM)
|
||
break;
|
||
SET_REGNO_REG_SET (set, regno);
|
||
}
|
||
#endif
|
||
#ifdef EH_RETURN_STACKADJ_RTX
|
||
if ((! HAVE_epilogue || ! reload_completed)
|
||
&& current_function_calls_eh_return)
|
||
{
|
||
rtx tmp = EH_RETURN_STACKADJ_RTX;
|
||
if (tmp && REG_P (tmp))
|
||
mark_reg (tmp, set);
|
||
}
|
||
#endif
|
||
#ifdef EH_RETURN_HANDLER_RTX
|
||
if ((! HAVE_epilogue || ! reload_completed)
|
||
&& current_function_calls_eh_return)
|
||
{
|
||
rtx tmp = EH_RETURN_HANDLER_RTX;
|
||
if (tmp && REG_P (tmp))
|
||
mark_reg (tmp, set);
|
||
}
|
||
#endif
|
||
|
||
/* Mark function return value. */
|
||
diddle_return_value (mark_reg, set);
|
||
}
|
||
|
||
/* Callback function for for_each_successor_phi. DATA is a regset.
|
||
Sets the SRC_REGNO, the regno of the phi alternative for phi node
|
||
INSN, in the regset. */
|
||
|
||
static int
|
||
set_phi_alternative_reg (insn, dest_regno, src_regno, data)
|
||
rtx insn ATTRIBUTE_UNUSED;
|
||
int dest_regno ATTRIBUTE_UNUSED;
|
||
int src_regno;
|
||
void *data;
|
||
{
|
||
regset live = (regset) data;
|
||
SET_REGNO_REG_SET (live, src_regno);
|
||
return 0;
|
||
}
|
||
|
||
/* Propagate global life info around the graph of basic blocks. Begin
|
||
considering blocks with their corresponding bit set in BLOCKS_IN.
|
||
If BLOCKS_IN is null, consider it the universal set.
|
||
|
||
BLOCKS_OUT is set for every block that was changed. */
|
||
|
||
static void
|
||
calculate_global_regs_live (blocks_in, blocks_out, flags)
|
||
sbitmap blocks_in, blocks_out;
|
||
int flags;
|
||
{
|
||
basic_block *queue, *qhead, *qtail, *qend;
|
||
regset tmp, new_live_at_end, call_used;
|
||
regset_head tmp_head, call_used_head;
|
||
regset_head new_live_at_end_head;
|
||
int i;
|
||
|
||
tmp = INITIALIZE_REG_SET (tmp_head);
|
||
new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
|
||
call_used = INITIALIZE_REG_SET (call_used_head);
|
||
|
||
/* Inconveniently, this is only readily available in hard reg set form. */
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
|
||
if (call_used_regs[i])
|
||
SET_REGNO_REG_SET (call_used, i);
|
||
|
||
/* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
|
||
because the `head == tail' style test for an empty queue doesn't
|
||
work with a full queue. */
|
||
queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
|
||
qtail = queue;
|
||
qhead = qend = queue + n_basic_blocks + 2;
|
||
|
||
/* Queue the blocks set in the initial mask. Do this in reverse block
|
||
number order so that we are more likely for the first round to do
|
||
useful work. We use AUX non-null to flag that the block is queued. */
|
||
if (blocks_in)
|
||
{
|
||
/* Clear out the garbage that might be hanging out in bb->aux. */
|
||
for (i = n_basic_blocks - 1; i >= 0; --i)
|
||
BASIC_BLOCK (i)->aux = NULL;
|
||
|
||
EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
*--qhead = bb;
|
||
bb->aux = bb;
|
||
});
|
||
}
|
||
else
|
||
{
|
||
for (i = 0; i < n_basic_blocks; ++i)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
*--qhead = bb;
|
||
bb->aux = bb;
|
||
}
|
||
}
|
||
|
||
if (blocks_out)
|
||
sbitmap_zero (blocks_out);
|
||
|
||
/* We work through the queue until there are no more blocks. What
|
||
is live at the end of this block is precisely the union of what
|
||
is live at the beginning of all its successors. So, we set its
|
||
GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
|
||
for its successors. Then, we compute GLOBAL_LIVE_AT_START for
|
||
this block by walking through the instructions in this block in
|
||
reverse order and updating as we go. If that changed
|
||
GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
|
||
queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
|
||
|
||
We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
|
||
never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
|
||
must either be live at the end of the block, or used within the
|
||
block. In the latter case, it will certainly never disappear
|
||
from GLOBAL_LIVE_AT_START. In the former case, the register
|
||
could go away only if it disappeared from GLOBAL_LIVE_AT_START
|
||
for one of the successor blocks. By induction, that cannot
|
||
occur. */
|
||
while (qhead != qtail)
|
||
{
|
||
int rescan, changed;
|
||
basic_block bb;
|
||
edge e;
|
||
|
||
bb = *qhead++;
|
||
if (qhead == qend)
|
||
qhead = queue;
|
||
bb->aux = NULL;
|
||
|
||
/* Begin by propagating live_at_start from the successor blocks. */
|
||
CLEAR_REG_SET (new_live_at_end);
|
||
for (e = bb->succ; e; e = e->succ_next)
|
||
{
|
||
basic_block sb = e->dest;
|
||
|
||
/* Call-clobbered registers die across exception and call edges. */
|
||
/* ??? Abnormal call edges ignored for the moment, as this gets
|
||
confused by sibling call edges, which crashes reg-stack. */
|
||
if (e->flags & EDGE_EH)
|
||
{
|
||
bitmap_operation (tmp, sb->global_live_at_start,
|
||
call_used, BITMAP_AND_COMPL);
|
||
IOR_REG_SET (new_live_at_end, tmp);
|
||
}
|
||
else
|
||
IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
|
||
}
|
||
|
||
/* The all-important stack pointer must always be live. */
|
||
SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
|
||
|
||
/* Before reload, there are a few registers that must be forced
|
||
live everywhere -- which might not already be the case for
|
||
blocks within infinite loops. */
|
||
if (! reload_completed)
|
||
{
|
||
/* Any reference to any pseudo before reload is a potential
|
||
reference of the frame pointer. */
|
||
SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
|
||
|
||
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
|
||
/* Pseudos with argument area equivalences may require
|
||
reloading via the argument pointer. */
|
||
if (fixed_regs[ARG_POINTER_REGNUM])
|
||
SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
|
||
#endif
|
||
|
||
/* Any constant, or pseudo with constant equivalences, may
|
||
require reloading from memory using the pic register. */
|
||
if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
|
||
&& fixed_regs[PIC_OFFSET_TABLE_REGNUM])
|
||
SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
|
||
}
|
||
|
||
/* Regs used in phi nodes are not included in
|
||
global_live_at_start, since they are live only along a
|
||
particular edge. Set those regs that are live because of a
|
||
phi node alternative corresponding to this particular block. */
|
||
if (in_ssa_form)
|
||
for_each_successor_phi (bb, &set_phi_alternative_reg,
|
||
new_live_at_end);
|
||
|
||
if (bb == ENTRY_BLOCK_PTR)
|
||
{
|
||
COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
|
||
continue;
|
||
}
|
||
|
||
/* On our first pass through this block, we'll go ahead and continue.
|
||
Recognize first pass by local_set NULL. On subsequent passes, we
|
||
get to skip out early if live_at_end wouldn't have changed. */
|
||
|
||
if (bb->local_set == NULL)
|
||
{
|
||
bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
|
||
bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
|
||
rescan = 1;
|
||
}
|
||
else
|
||
{
|
||
/* If any bits were removed from live_at_end, we'll have to
|
||
rescan the block. This wouldn't be necessary if we had
|
||
precalculated local_live, however with PROP_SCAN_DEAD_CODE
|
||
local_live is really dependent on live_at_end. */
|
||
CLEAR_REG_SET (tmp);
|
||
rescan = bitmap_operation (tmp, bb->global_live_at_end,
|
||
new_live_at_end, BITMAP_AND_COMPL);
|
||
|
||
if (! rescan)
|
||
{
|
||
/* If any of the registers in the new live_at_end set are
|
||
conditionally set in this basic block, we must rescan.
|
||
This is because conditional lifetimes at the end of the
|
||
block do not just take the live_at_end set into account,
|
||
but also the liveness at the start of each successor
|
||
block. We can miss changes in those sets if we only
|
||
compare the new live_at_end against the previous one. */
|
||
CLEAR_REG_SET (tmp);
|
||
rescan = bitmap_operation (tmp, new_live_at_end,
|
||
bb->cond_local_set, BITMAP_AND);
|
||
}
|
||
|
||
if (! rescan)
|
||
{
|
||
/* Find the set of changed bits. Take this opportunity
|
||
to notice that this set is empty and early out. */
|
||
CLEAR_REG_SET (tmp);
|
||
changed = bitmap_operation (tmp, bb->global_live_at_end,
|
||
new_live_at_end, BITMAP_XOR);
|
||
if (! changed)
|
||
continue;
|
||
|
||
/* If any of the changed bits overlap with local_set,
|
||
we'll have to rescan the block. Detect overlap by
|
||
the AND with ~local_set turning off bits. */
|
||
rescan = bitmap_operation (tmp, tmp, bb->local_set,
|
||
BITMAP_AND_COMPL);
|
||
}
|
||
}
|
||
|
||
/* Let our caller know that BB changed enough to require its
|
||
death notes updated. */
|
||
if (blocks_out)
|
||
SET_BIT (blocks_out, bb->index);
|
||
|
||
if (! rescan)
|
||
{
|
||
/* Add to live_at_start the set of all registers in
|
||
new_live_at_end that aren't in the old live_at_end. */
|
||
|
||
bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
|
||
BITMAP_AND_COMPL);
|
||
COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
|
||
|
||
changed = bitmap_operation (bb->global_live_at_start,
|
||
bb->global_live_at_start,
|
||
tmp, BITMAP_IOR);
|
||
if (! changed)
|
||
continue;
|
||
}
|
||
else
|
||
{
|
||
COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
|
||
|
||
/* Rescan the block insn by insn to turn (a copy of) live_at_end
|
||
into live_at_start. */
|
||
propagate_block (bb, new_live_at_end, bb->local_set,
|
||
bb->cond_local_set, flags);
|
||
|
||
/* If live_at start didn't change, no need to go farther. */
|
||
if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
|
||
continue;
|
||
|
||
COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
|
||
}
|
||
|
||
/* Queue all predecessors of BB so that we may re-examine
|
||
their live_at_end. */
|
||
for (e = bb->pred; e; e = e->pred_next)
|
||
{
|
||
basic_block pb = e->src;
|
||
if (pb->aux == NULL)
|
||
{
|
||
*qtail++ = pb;
|
||
if (qtail == qend)
|
||
qtail = queue;
|
||
pb->aux = pb;
|
||
}
|
||
}
|
||
}
|
||
|
||
FREE_REG_SET (tmp);
|
||
FREE_REG_SET (new_live_at_end);
|
||
FREE_REG_SET (call_used);
|
||
|
||
if (blocks_out)
|
||
{
|
||
EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
FREE_REG_SET (bb->local_set);
|
||
FREE_REG_SET (bb->cond_local_set);
|
||
});
|
||
}
|
||
else
|
||
{
|
||
for (i = n_basic_blocks - 1; i >= 0; --i)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
FREE_REG_SET (bb->local_set);
|
||
FREE_REG_SET (bb->cond_local_set);
|
||
}
|
||
}
|
||
|
||
free (queue);
|
||
}
|
||
|
||
|
||
/* This structure is used to pass parameters to an from the
|
||
the function find_regno_partial(). It is used to pass in the
|
||
register number we are looking, as well as to return any rtx
|
||
we find. */
|
||
|
||
typedef struct {
|
||
unsigned regno_to_find;
|
||
rtx retval;
|
||
} find_regno_partial_param;
|
||
|
||
|
||
/* Find the rtx for the reg numbers specified in 'data' if it is
|
||
part of an expression which only uses part of the register. Return
|
||
it in the structure passed in. */
|
||
static int
|
||
find_regno_partial (ptr, data)
|
||
rtx *ptr;
|
||
void *data;
|
||
{
|
||
find_regno_partial_param *param = (find_regno_partial_param *)data;
|
||
unsigned reg = param->regno_to_find;
|
||
param->retval = NULL_RTX;
|
||
|
||
if (*ptr == NULL_RTX)
|
||
return 0;
|
||
|
||
switch (GET_CODE (*ptr))
|
||
{
|
||
case ZERO_EXTRACT:
|
||
case SIGN_EXTRACT:
|
||
case STRICT_LOW_PART:
|
||
if (GET_CODE (XEXP (*ptr, 0)) == REG && REGNO (XEXP (*ptr, 0)) == reg)
|
||
{
|
||
param->retval = XEXP (*ptr, 0);
|
||
return 1;
|
||
}
|
||
break;
|
||
|
||
case SUBREG:
|
||
if (GET_CODE (SUBREG_REG (*ptr)) == REG
|
||
&& REGNO (SUBREG_REG (*ptr)) == reg)
|
||
{
|
||
param->retval = SUBREG_REG (*ptr);
|
||
return 1;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Process all immediate successors of the entry block looking for pseudo
|
||
registers which are live on entry. Find all of those whose first
|
||
instance is a partial register reference of some kind, and initialize
|
||
them to 0 after the entry block. This will prevent bit sets within
|
||
registers whose value is unknown, and may contain some kind of sticky
|
||
bits we don't want. */
|
||
|
||
int
|
||
initialize_uninitialized_subregs ()
|
||
{
|
||
rtx insn;
|
||
edge e;
|
||
int reg, did_something = 0;
|
||
find_regno_partial_param param;
|
||
|
||
for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
|
||
{
|
||
basic_block bb = e->dest;
|
||
regset map = bb->global_live_at_start;
|
||
EXECUTE_IF_SET_IN_REG_SET (map,
|
||
FIRST_PSEUDO_REGISTER, reg,
|
||
{
|
||
int uid = REGNO_FIRST_UID (reg);
|
||
rtx i;
|
||
|
||
/* Find an insn which mentions the register we are looking for.
|
||
Its preferable to have an instance of the register's rtl since
|
||
there may be various flags set which we need to duplicate.
|
||
If we can't find it, its probably an automatic whose initial
|
||
value doesn't matter, or hopefully something we don't care about. */
|
||
for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
|
||
;
|
||
if (i != NULL_RTX)
|
||
{
|
||
/* Found the insn, now get the REG rtx, if we can. */
|
||
param.regno_to_find = reg;
|
||
for_each_rtx (&i, find_regno_partial, ¶m);
|
||
if (param.retval != NULL_RTX)
|
||
{
|
||
insn = gen_move_insn (param.retval,
|
||
CONST0_RTX (GET_MODE (param.retval)));
|
||
insert_insn_on_edge (insn, e);
|
||
did_something = 1;
|
||
}
|
||
}
|
||
});
|
||
}
|
||
|
||
if (did_something)
|
||
commit_edge_insertions ();
|
||
return did_something;
|
||
}
|
||
|
||
|
||
/* 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 ()
|
||
{
|
||
int i;
|
||
|
||
for (i = 0; i < n_basic_blocks; i++)
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
|
||
bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
|
||
}
|
||
|
||
ENTRY_BLOCK_PTR->global_live_at_end
|
||
= OBSTACK_ALLOC_REG_SET (&flow_obstack);
|
||
EXIT_BLOCK_PTR->global_live_at_start
|
||
= OBSTACK_ALLOC_REG_SET (&flow_obstack);
|
||
|
||
regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
|
||
}
|
||
|
||
void
|
||
allocate_reg_life_data ()
|
||
{
|
||
int i;
|
||
|
||
max_regno = max_reg_num ();
|
||
|
||
/* 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);
|
||
|
||
/* Reset all the data we'll collect in propagate_block and its
|
||
subroutines. */
|
||
for (i = 0; i < max_regno; i++)
|
||
{
|
||
REG_N_SETS (i) = 0;
|
||
REG_N_REFS (i) = 0;
|
||
REG_N_DEATHS (i) = 0;
|
||
REG_N_CALLS_CROSSED (i) = 0;
|
||
REG_LIVE_LENGTH (i) = 0;
|
||
REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
|
||
}
|
||
}
|
||
|
||
/* Delete dead instructions for propagate_block. */
|
||
|
||
static void
|
||
propagate_block_delete_insn (bb, insn)
|
||
basic_block bb;
|
||
rtx insn;
|
||
{
|
||
rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
|
||
bool purge = false;
|
||
|
||
/* If the insn referred to a label, and that 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.
|
||
|
||
INSN may reference a deleted label, particularly when a jump
|
||
table has been optimized into a direct jump. There's no
|
||
real good way to fix up the reference to the deleted label
|
||
when the label is deleted, so we just allow it here.
|
||
|
||
After dead code elimination is complete, we do search for
|
||
any REG_LABEL notes which reference deleted labels as a
|
||
sanity check. */
|
||
|
||
if (inote && GET_CODE (inote) == CODE_LABEL)
|
||
{
|
||
rtx label = XEXP (inote, 0);
|
||
rtx next;
|
||
|
||
/* The label may be forced if it has been put in the constant
|
||
pool. If that is the only use we must discard the table
|
||
jump following it, but not the label itself. */
|
||
if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
|
||
&& (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))--;
|
||
|
||
delete_insn (next);
|
||
}
|
||
}
|
||
|
||
if (bb->end == insn)
|
||
purge = true;
|
||
delete_insn (insn);
|
||
if (purge)
|
||
purge_dead_edges (bb);
|
||
}
|
||
|
||
/* Delete dead libcalls for propagate_block. Return the insn
|
||
before the libcall. */
|
||
|
||
static rtx
|
||
propagate_block_delete_libcall ( insn, note)
|
||
rtx insn, note;
|
||
{
|
||
rtx first = XEXP (note, 0);
|
||
rtx before = PREV_INSN (first);
|
||
|
||
delete_insn_chain (first, insn);
|
||
return before;
|
||
}
|
||
|
||
/* Update the life-status of regs for one insn. Return the previous insn. */
|
||
|
||
rtx
|
||
propagate_one_insn (pbi, insn)
|
||
struct propagate_block_info *pbi;
|
||
rtx insn;
|
||
{
|
||
rtx prev = PREV_INSN (insn);
|
||
int flags = pbi->flags;
|
||
int insn_is_dead = 0;
|
||
int libcall_is_dead = 0;
|
||
rtx note;
|
||
int i;
|
||
|
||
if (! INSN_P (insn))
|
||
return prev;
|
||
|
||
note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
|
||
if (flags & PROP_SCAN_DEAD_CODE)
|
||
{
|
||
insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
|
||
libcall_is_dead = (insn_is_dead && note != 0
|
||
&& libcall_dead_p (pbi, note, insn));
|
||
}
|
||
|
||
/* If an instruction consists of just dead store(s) on final pass,
|
||
delete it. */
|
||
if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
|
||
{
|
||
/* If we're trying to delete a prologue or epilogue instruction
|
||
that isn't flagged as possibly being dead, something is wrong.
|
||
But if we are keeping the stack pointer depressed, we might well
|
||
be deleting insns that are used to compute the amount to update
|
||
it by, so they are fine. */
|
||
if (reload_completed
|
||
&& !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
|
||
&& (TYPE_RETURNS_STACK_DEPRESSED
|
||
(TREE_TYPE (current_function_decl))))
|
||
&& (((HAVE_epilogue || HAVE_prologue)
|
||
&& prologue_epilogue_contains (insn))
|
||
|| (HAVE_sibcall_epilogue
|
||
&& sibcall_epilogue_contains (insn)))
|
||
&& find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
|
||
fatal_insn ("Attempt to delete prologue/epilogue insn:", insn);
|
||
|
||
/* Record sets. Do this even for dead instructions, since they
|
||
would have killed the values if they hadn't been deleted. */
|
||
mark_set_regs (pbi, PATTERN (insn), insn);
|
||
|
||
/* 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. */
|
||
pbi->cc0_live = 0;
|
||
|
||
if (libcall_is_dead)
|
||
prev = propagate_block_delete_libcall ( insn, note);
|
||
else
|
||
propagate_block_delete_insn (pbi->bb, insn);
|
||
|
||
return prev;
|
||
}
|
||
|
||
/* See if this is an increment or decrement that can be merged into
|
||
a following memory address. */
|
||
#ifdef AUTO_INC_DEC
|
||
{
|
||
rtx x = single_set (insn);
|
||
|
||
/* Does this instruction increment or decrement a register? */
|
||
if ((flags & PROP_AUTOINC)
|
||
&& 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 (pbi, insn))
|
||
return prev;
|
||
}
|
||
#endif /* AUTO_INC_DEC */
|
||
|
||
CLEAR_REG_SET (pbi->new_set);
|
||
|
||
/* 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)
|
||
{
|
||
/* Record the death of the dest reg. */
|
||
mark_set_regs (pbi, PATTERN (insn), insn);
|
||
|
||
insn = XEXP (note, 0);
|
||
return 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
|
||
{
|
||
rtx note;
|
||
/* 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 && (flags & PROP_REG_INFO))
|
||
EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
|
||
{ REG_N_CALLS_CROSSED (i)++; });
|
||
|
||
/* Record sets. Do this even for dead instructions, since they
|
||
would have killed the values if they hadn't been deleted. */
|
||
mark_set_regs (pbi, PATTERN (insn), insn);
|
||
|
||
if (GET_CODE (insn) == CALL_INSN)
|
||
{
|
||
int i;
|
||
rtx note, cond;
|
||
|
||
cond = NULL_RTX;
|
||
if (GET_CODE (PATTERN (insn)) == COND_EXEC)
|
||
cond = COND_EXEC_TEST (PATTERN (insn));
|
||
|
||
/* Non-constant calls clobber memory. */
|
||
if (! CONST_OR_PURE_CALL_P (insn))
|
||
{
|
||
free_EXPR_LIST_list (&pbi->mem_set_list);
|
||
pbi->mem_set_list_len = 0;
|
||
}
|
||
|
||
/* There may be extra registers to be clobbered. */
|
||
for (note = CALL_INSN_FUNCTION_USAGE (insn);
|
||
note;
|
||
note = XEXP (note, 1))
|
||
if (GET_CODE (XEXP (note, 0)) == CLOBBER)
|
||
mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
|
||
cond, insn, pbi->flags);
|
||
|
||
/* Calls change all call-used and global registers. */
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
|
||
{
|
||
/* We do not want REG_UNUSED notes for these registers. */
|
||
mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
|
||
cond, insn,
|
||
pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
|
||
}
|
||
}
|
||
|
||
/* 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. */
|
||
pbi->cc0_live = 0;
|
||
|
||
/* Record uses. */
|
||
if (! insn_is_dead)
|
||
mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
|
||
if ((flags & PROP_EQUAL_NOTES)
|
||
&& ((note = find_reg_note (insn, REG_EQUAL, NULL_RTX))
|
||
|| (note = find_reg_note (insn, REG_EQUIV, NULL_RTX))))
|
||
mark_used_regs (pbi, XEXP (note, 0), NULL_RTX, 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)
|
||
{
|
||
int i;
|
||
rtx note, cond;
|
||
|
||
cond = NULL_RTX;
|
||
if (GET_CODE (PATTERN (insn)) == COND_EXEC)
|
||
cond = COND_EXEC_TEST (PATTERN (insn));
|
||
|
||
/* Calls use their arguments. */
|
||
for (note = CALL_INSN_FUNCTION_USAGE (insn);
|
||
note;
|
||
note = XEXP (note, 1))
|
||
if (GET_CODE (XEXP (note, 0)) == USE)
|
||
mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
|
||
cond, insn);
|
||
|
||
/* The stack ptr is used (honorarily) by a CALL insn. */
|
||
SET_REGNO_REG_SET (pbi->reg_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_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
|
||
cond, insn);
|
||
}
|
||
}
|
||
|
||
/* On final pass, update counts of how many insns in which each reg
|
||
is live. */
|
||
if (flags & PROP_REG_INFO)
|
||
EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
|
||
{ REG_LIVE_LENGTH (i)++; });
|
||
|
||
return prev;
|
||
}
|
||
|
||
/* Initialize a propagate_block_info struct for public consumption.
|
||
Note that the structure itself is opaque to this file, but that
|
||
the user can use the regsets provided here. */
|
||
|
||
struct propagate_block_info *
|
||
init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
|
||
basic_block bb;
|
||
regset live, local_set, cond_local_set;
|
||
int flags;
|
||
{
|
||
struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
|
||
|
||
pbi->bb = bb;
|
||
pbi->reg_live = live;
|
||
pbi->mem_set_list = NULL_RTX;
|
||
pbi->mem_set_list_len = 0;
|
||
pbi->local_set = local_set;
|
||
pbi->cond_local_set = cond_local_set;
|
||
pbi->cc0_live = 0;
|
||
pbi->flags = flags;
|
||
|
||
if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
|
||
pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
|
||
else
|
||
pbi->reg_next_use = NULL;
|
||
|
||
pbi->new_set = BITMAP_XMALLOC ();
|
||
|
||
#ifdef HAVE_conditional_execution
|
||
pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
|
||
free_reg_cond_life_info);
|
||
pbi->reg_cond_reg = BITMAP_XMALLOC ();
|
||
|
||
/* If this block ends in a conditional branch, for each register live
|
||
from one side of the branch and not the other, record the register
|
||
as conditionally dead. */
|
||
if (GET_CODE (bb->end) == JUMP_INSN
|
||
&& any_condjump_p (bb->end))
|
||
{
|
||
regset_head diff_head;
|
||
regset diff = INITIALIZE_REG_SET (diff_head);
|
||
basic_block bb_true, bb_false;
|
||
rtx cond_true, cond_false, set_src;
|
||
int i;
|
||
|
||
/* Identify the successor blocks. */
|
||
bb_true = bb->succ->dest;
|
||
if (bb->succ->succ_next != NULL)
|
||
{
|
||
bb_false = bb->succ->succ_next->dest;
|
||
|
||
if (bb->succ->flags & EDGE_FALLTHRU)
|
||
{
|
||
basic_block t = bb_false;
|
||
bb_false = bb_true;
|
||
bb_true = t;
|
||
}
|
||
else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
|
||
abort ();
|
||
}
|
||
else
|
||
{
|
||
/* This can happen with a conditional jump to the next insn. */
|
||
if (JUMP_LABEL (bb->end) != bb_true->head)
|
||
abort ();
|
||
|
||
/* Simplest way to do nothing. */
|
||
bb_false = bb_true;
|
||
}
|
||
|
||
/* Extract the condition from the branch. */
|
||
set_src = SET_SRC (pc_set (bb->end));
|
||
cond_true = XEXP (set_src, 0);
|
||
cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
|
||
GET_MODE (cond_true), XEXP (cond_true, 0),
|
||
XEXP (cond_true, 1));
|
||
if (GET_CODE (XEXP (set_src, 1)) == PC)
|
||
{
|
||
rtx t = cond_false;
|
||
cond_false = cond_true;
|
||
cond_true = t;
|
||
}
|
||
|
||
/* Compute which register lead different lives in the successors. */
|
||
if (bitmap_operation (diff, bb_true->global_live_at_start,
|
||
bb_false->global_live_at_start, BITMAP_XOR))
|
||
{
|
||
rtx reg = XEXP (cond_true, 0);
|
||
|
||
if (GET_CODE (reg) == SUBREG)
|
||
reg = SUBREG_REG (reg);
|
||
|
||
if (GET_CODE (reg) != REG)
|
||
abort ();
|
||
|
||
SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
|
||
|
||
/* For each such register, mark it conditionally dead. */
|
||
EXECUTE_IF_SET_IN_REG_SET
|
||
(diff, 0, i,
|
||
{
|
||
struct reg_cond_life_info *rcli;
|
||
rtx cond;
|
||
|
||
rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
|
||
|
||
if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
|
||
cond = cond_false;
|
||
else
|
||
cond = cond_true;
|
||
rcli->condition = cond;
|
||
rcli->stores = const0_rtx;
|
||
rcli->orig_condition = cond;
|
||
|
||
splay_tree_insert (pbi->reg_cond_dead, i,
|
||
(splay_tree_value) rcli);
|
||
});
|
||
}
|
||
|
||
FREE_REG_SET (diff);
|
||
}
|
||
#endif
|
||
|
||
/* If this block has no successors, any stores to the frame that aren't
|
||
used later in the block are dead. So make a pass over the block
|
||
recording any such that are made and show them dead at the end. We do
|
||
a very conservative and simple job here. */
|
||
if (optimize
|
||
&& ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
|
||
&& (TYPE_RETURNS_STACK_DEPRESSED
|
||
(TREE_TYPE (current_function_decl))))
|
||
&& (flags & PROP_SCAN_DEAD_CODE)
|
||
&& (bb->succ == NULL
|
||
|| (bb->succ->succ_next == NULL
|
||
&& bb->succ->dest == EXIT_BLOCK_PTR
|
||
&& ! current_function_calls_eh_return)))
|
||
{
|
||
rtx insn, set;
|
||
for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
|
||
if (GET_CODE (insn) == INSN
|
||
&& (set = single_set (insn))
|
||
&& GET_CODE (SET_DEST (set)) == MEM)
|
||
{
|
||
rtx mem = SET_DEST (set);
|
||
rtx canon_mem = canon_rtx (mem);
|
||
|
||
/* This optimization is performed by faking a store to the
|
||
memory at the end of the block. This doesn't work for
|
||
unchanging memories because multiple stores to unchanging
|
||
memory is illegal and alias analysis doesn't consider it. */
|
||
if (RTX_UNCHANGING_P (canon_mem))
|
||
continue;
|
||
|
||
if (XEXP (canon_mem, 0) == frame_pointer_rtx
|
||
|| (GET_CODE (XEXP (canon_mem, 0)) == PLUS
|
||
&& XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
|
||
&& GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
|
||
add_to_mem_set_list (pbi, canon_mem);
|
||
}
|
||
}
|
||
|
||
return pbi;
|
||
}
|
||
|
||
/* Release a propagate_block_info struct. */
|
||
|
||
void
|
||
free_propagate_block_info (pbi)
|
||
struct propagate_block_info *pbi;
|
||
{
|
||
free_EXPR_LIST_list (&pbi->mem_set_list);
|
||
|
||
BITMAP_XFREE (pbi->new_set);
|
||
|
||
#ifdef HAVE_conditional_execution
|
||
splay_tree_delete (pbi->reg_cond_dead);
|
||
BITMAP_XFREE (pbi->reg_cond_reg);
|
||
#endif
|
||
|
||
if (pbi->reg_next_use)
|
||
free (pbi->reg_next_use);
|
||
|
||
free (pbi);
|
||
}
|
||
|
||
/* Compute the registers live at the beginning of a basic block BB from
|
||
those live at the end.
|
||
|
||
When called, REG_LIVE contains those live at the end. On return, it
|
||
contains those live at the beginning.
|
||
|
||
LOCAL_SET, if non-null, will be set with all registers killed
|
||
unconditionally by this basic block.
|
||
Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
|
||
killed conditionally by this basic block. If there is any unconditional
|
||
set of a register, then the corresponding bit will be set in LOCAL_SET
|
||
and cleared in COND_LOCAL_SET.
|
||
It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
|
||
case, the resulting set will be equal to the union of the two sets that
|
||
would otherwise be computed.
|
||
|
||
Return non-zero if an INSN is deleted (i.e. by dead code removal). */
|
||
|
||
int
|
||
propagate_block (bb, live, local_set, cond_local_set, flags)
|
||
basic_block bb;
|
||
regset live;
|
||
regset local_set;
|
||
regset cond_local_set;
|
||
int flags;
|
||
{
|
||
struct propagate_block_info *pbi;
|
||
rtx insn, prev;
|
||
int changed;
|
||
|
||
pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
|
||
|
||
if (flags & PROP_REG_INFO)
|
||
{
|
||
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 (live, 0, i,
|
||
{ REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
|
||
}
|
||
|
||
/* Scan the block an insn at a time from end to beginning. */
|
||
|
||
changed = 0;
|
||
for (insn = bb->end;; insn = prev)
|
||
{
|
||
/* If this is a call to `setjmp' et al, warn if any
|
||
non-volatile datum is live. */
|
||
if ((flags & PROP_REG_INFO)
|
||
&& GET_CODE (insn) == CALL_INSN
|
||
&& find_reg_note (insn, REG_SETJMP, NULL))
|
||
IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
|
||
|
||
prev = propagate_one_insn (pbi, insn);
|
||
changed |= NEXT_INSN (prev) != insn;
|
||
|
||
if (insn == bb->head)
|
||
break;
|
||
}
|
||
|
||
free_propagate_block_info (pbi);
|
||
|
||
return changed;
|
||
}
|
||
|
||
/* 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 (pbi, x, call_ok, notes)
|
||
struct propagate_block_info *pbi;
|
||
rtx x;
|
||
int call_ok;
|
||
rtx notes ATTRIBUTE_UNUSED;
|
||
{
|
||
enum rtx_code code = GET_CODE (x);
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
/* As flow is invoked after combine, we must take existing AUTO_INC
|
||
expressions into account. */
|
||
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 (pbi->reg_live, 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);
|
||
|
||
#ifdef HAVE_cc0
|
||
if (GET_CODE (r) == CC0)
|
||
return ! pbi->cc0_live;
|
||
#endif
|
||
|
||
/* A SET that is a subroutine call cannot be dead. */
|
||
if (GET_CODE (SET_SRC (x)) == CALL)
|
||
{
|
||
if (! call_ok)
|
||
return 0;
|
||
}
|
||
|
||
/* Don't eliminate loads from volatile memory or volatile asms. */
|
||
else if (volatile_refs_p (SET_SRC (x)))
|
||
return 0;
|
||
|
||
if (GET_CODE (r) == MEM)
|
||
{
|
||
rtx temp, canon_r;
|
||
|
||
if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
|
||
return 0;
|
||
|
||
canon_r = canon_rtx (r);
|
||
|
||
/* 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). Since
|
||
rtx_equal_p does not check the alias set or flags, we also
|
||
must have the potential for them to conflict (anti_dependence). */
|
||
for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
|
||
if (anti_dependence (r, XEXP (temp, 0)))
|
||
{
|
||
rtx mem = XEXP (temp, 0);
|
||
|
||
if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
|
||
&& (GET_MODE_SIZE (GET_MODE (canon_r))
|
||
<= GET_MODE_SIZE (GET_MODE (mem))))
|
||
return 1;
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
/* Check if memory reference matches an auto increment. Only
|
||
post increment/decrement or modify are valid. */
|
||
if (GET_MODE (mem) == GET_MODE (r)
|
||
&& (GET_CODE (XEXP (mem, 0)) == POST_DEC
|
||
|| GET_CODE (XEXP (mem, 0)) == POST_INC
|
||
|| GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
|
||
&& GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
|
||
&& rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
|
||
return 1;
|
||
#endif
|
||
}
|
||
}
|
||
else
|
||
{
|
||
while (GET_CODE (r) == SUBREG
|
||
|| GET_CODE (r) == STRICT_LOW_PART
|
||
|| GET_CODE (r) == ZERO_EXTRACT)
|
||
r = XEXP (r, 0);
|
||
|
||
if (GET_CODE (r) == REG)
|
||
{
|
||
int regno = REGNO (r);
|
||
|
||
/* Obvious. */
|
||
if (REGNO_REG_SET_P (pbi->reg_live, 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 (pbi->reg_live, regno+n))
|
||
return 0;
|
||
}
|
||
|
||
/* Don't delete insns to set global regs. */
|
||
if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
|
||
return 0;
|
||
|
||
/* Make sure insns to set the stack pointer aren't deleted. */
|
||
if (regno == STACK_POINTER_REGNUM)
|
||
return 0;
|
||
|
||
/* ??? These bits might be redundant with the force live bits
|
||
in calculate_global_regs_live. We would delete from
|
||
sequential sets; whether this actually affects real code
|
||
for anything but the stack pointer I don't know. */
|
||
/* Make sure insns to set the frame pointer aren't deleted. */
|
||
if (regno == FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
return 0;
|
||
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
|
||
if (regno == HARD_FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
return 0;
|
||
#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). */
|
||
if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
|
||
return 0;
|
||
#endif
|
||
|
||
/* Otherwise, the set is dead. */
|
||
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 (pbi, XVECEXP (x, 0, i), 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 (pbi->reg_live, 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 INSN is the last insn in a libcall, and assuming INSN is dead,
|
||
return 1 if the entire library call is dead.
|
||
This is true if INSN 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 the SET inside
|
||
INSN 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.
|
||
|
||
PBI is the block info giving pseudoregs live before this insn.
|
||
NOTE is the REG_RETVAL note of the insn. */
|
||
|
||
static int
|
||
libcall_dead_p (pbi, note, insn)
|
||
struct propagate_block_info *pbi;
|
||
rtx note;
|
||
rtx insn;
|
||
{
|
||
rtx x = single_set (insn);
|
||
|
||
if (x)
|
||
{
|
||
rtx r = SET_SRC (x);
|
||
|
||
if (GET_CODE (r) == REG)
|
||
{
|
||
rtx call = XEXP (note, 0);
|
||
rtx call_pat;
|
||
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 (pbi, call_pat, 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)
|
||
unsigned 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));
|
||
}
|
||
|
||
/* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
|
||
maximal list size; look for overlaps in mode and select the largest. */
|
||
static void
|
||
add_to_mem_set_list (pbi, mem)
|
||
struct propagate_block_info *pbi;
|
||
rtx mem;
|
||
{
|
||
rtx i;
|
||
|
||
/* We don't know how large a BLKmode store is, so we must not
|
||
take them into consideration. */
|
||
if (GET_MODE (mem) == BLKmode)
|
||
return;
|
||
|
||
for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
|
||
{
|
||
rtx e = XEXP (i, 0);
|
||
if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
|
||
{
|
||
if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
|
||
{
|
||
#ifdef AUTO_INC_DEC
|
||
/* If we must store a copy of the mem, we can just modify
|
||
the mode of the stored copy. */
|
||
if (pbi->flags & PROP_AUTOINC)
|
||
PUT_MODE (e, GET_MODE (mem));
|
||
else
|
||
#endif
|
||
XEXP (i, 0) = mem;
|
||
}
|
||
return;
|
||
}
|
||
}
|
||
|
||
if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
|
||
{
|
||
#ifdef AUTO_INC_DEC
|
||
/* Store a copy of mem, otherwise the address may be
|
||
scrogged by find_auto_inc. */
|
||
if (pbi->flags & PROP_AUTOINC)
|
||
mem = shallow_copy_rtx (mem);
|
||
#endif
|
||
pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
|
||
pbi->mem_set_list_len++;
|
||
}
|
||
}
|
||
|
||
/* 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 (pbi, insn)
|
||
struct propagate_block_info *pbi;
|
||
rtx insn;
|
||
{
|
||
rtx note = REG_NOTES (insn);
|
||
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
|
||
if (REG_NOTE_KIND (note) == REG_INC)
|
||
invalidate_mems_from_set (pbi, XEXP (note, 0));
|
||
}
|
||
|
||
/* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
|
||
|
||
static void
|
||
invalidate_mems_from_set (pbi, exp)
|
||
struct propagate_block_info *pbi;
|
||
rtx exp;
|
||
{
|
||
rtx temp = pbi->mem_set_list;
|
||
rtx prev = NULL_RTX;
|
||
rtx next;
|
||
|
||
while (temp)
|
||
{
|
||
next = XEXP (temp, 1);
|
||
if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
|
||
{
|
||
/* Splice this entry out of the list. */
|
||
if (prev)
|
||
XEXP (prev, 1) = next;
|
||
else
|
||
pbi->mem_set_list = next;
|
||
free_EXPR_LIST_node (temp);
|
||
pbi->mem_set_list_len--;
|
||
}
|
||
else
|
||
prev = temp;
|
||
temp = next;
|
||
}
|
||
}
|
||
|
||
/* 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.
|
||
|
||
FLAGS is the set of operations to perform. */
|
||
|
||
static void
|
||
mark_set_regs (pbi, x, insn)
|
||
struct propagate_block_info *pbi;
|
||
rtx x, insn;
|
||
{
|
||
rtx cond = NULL_RTX;
|
||
rtx link;
|
||
enum rtx_code code;
|
||
|
||
if (insn)
|
||
for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
|
||
{
|
||
if (REG_NOTE_KIND (link) == REG_INC)
|
||
mark_set_1 (pbi, SET, XEXP (link, 0),
|
||
(GET_CODE (x) == COND_EXEC
|
||
? COND_EXEC_TEST (x) : NULL_RTX),
|
||
insn, pbi->flags);
|
||
}
|
||
retry:
|
||
switch (code = GET_CODE (x))
|
||
{
|
||
case SET:
|
||
case CLOBBER:
|
||
mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
|
||
return;
|
||
|
||
case COND_EXEC:
|
||
cond = COND_EXEC_TEST (x);
|
||
x = COND_EXEC_CODE (x);
|
||
goto retry;
|
||
|
||
case PARALLEL:
|
||
{
|
||
int i;
|
||
|
||
for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
|
||
{
|
||
rtx sub = XVECEXP (x, 0, i);
|
||
switch (code = GET_CODE (sub))
|
||
{
|
||
case COND_EXEC:
|
||
if (cond != NULL_RTX)
|
||
abort ();
|
||
|
||
cond = COND_EXEC_TEST (sub);
|
||
sub = COND_EXEC_CODE (sub);
|
||
if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
|
||
break;
|
||
/* Fall through. */
|
||
|
||
case SET:
|
||
case CLOBBER:
|
||
mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
break;
|
||
}
|
||
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Process a single set, which appears in INSN. REG (which may not
|
||
actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
|
||
being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
|
||
If the set is conditional (because it appear in a COND_EXEC), COND
|
||
will be the condition. */
|
||
|
||
static void
|
||
mark_set_1 (pbi, code, reg, cond, insn, flags)
|
||
struct propagate_block_info *pbi;
|
||
enum rtx_code code;
|
||
rtx reg, cond, insn;
|
||
int flags;
|
||
{
|
||
int regno_first = -1, regno_last = -1;
|
||
unsigned long not_dead = 0;
|
||
int i;
|
||
|
||
/* 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. Of course, if it was dead after it's unused now. */
|
||
|
||
switch (GET_CODE (reg))
|
||
{
|
||
case PARALLEL:
|
||
/* 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. */
|
||
for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
|
||
if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
|
||
mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
|
||
flags);
|
||
return;
|
||
|
||
case ZERO_EXTRACT:
|
||
case SIGN_EXTRACT:
|
||
case STRICT_LOW_PART:
|
||
/* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
|
||
do
|
||
reg = XEXP (reg, 0);
|
||
while (GET_CODE (reg) == SUBREG
|
||
|| GET_CODE (reg) == ZERO_EXTRACT
|
||
|| GET_CODE (reg) == SIGN_EXTRACT
|
||
|| GET_CODE (reg) == STRICT_LOW_PART);
|
||
if (GET_CODE (reg) == MEM)
|
||
break;
|
||
not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
|
||
/* Fall through. */
|
||
|
||
case REG:
|
||
regno_last = regno_first = REGNO (reg);
|
||
if (regno_first < FIRST_PSEUDO_REGISTER)
|
||
regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
|
||
break;
|
||
|
||
case SUBREG:
|
||
if (GET_CODE (SUBREG_REG (reg)) == REG)
|
||
{
|
||
enum machine_mode outer_mode = GET_MODE (reg);
|
||
enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
|
||
|
||
/* Identify the range of registers affected. This is moderately
|
||
tricky for hard registers. See alter_subreg. */
|
||
|
||
regno_last = regno_first = REGNO (SUBREG_REG (reg));
|
||
if (regno_first < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
regno_first += subreg_regno_offset (regno_first, inner_mode,
|
||
SUBREG_BYTE (reg),
|
||
outer_mode);
|
||
regno_last = (regno_first
|
||
+ HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
|
||
|
||
/* Since we've just adjusted the register number ranges, make
|
||
sure REG matches. Otherwise some_was_live will be clear
|
||
when it shouldn't have been, and we'll create incorrect
|
||
REG_UNUSED notes. */
|
||
reg = gen_rtx_REG (outer_mode, regno_first);
|
||
}
|
||
else
|
||
{
|
||
/* If the number of words in the subreg is less than the number
|
||
of words in the full register, we have a well-defined partial
|
||
set. Otherwise the high bits are undefined.
|
||
|
||
This is only really applicable to pseudos, since we just took
|
||
care of multi-word hard registers. */
|
||
if (((GET_MODE_SIZE (outer_mode)
|
||
+ UNITS_PER_WORD - 1) / UNITS_PER_WORD)
|
||
< ((GET_MODE_SIZE (inner_mode)
|
||
+ UNITS_PER_WORD - 1) / UNITS_PER_WORD))
|
||
not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
|
||
regno_first);
|
||
|
||
reg = SUBREG_REG (reg);
|
||
}
|
||
}
|
||
else
|
||
reg = SUBREG_REG (reg);
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* 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 (optimize && (flags & PROP_SCAN_DEAD_CODE))
|
||
{
|
||
if (GET_CODE (reg) == REG)
|
||
invalidate_mems_from_set (pbi, reg);
|
||
|
||
/* 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 (pbi, insn);
|
||
|
||
if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
|
||
/* ??? With more effort we could track conditional memory life. */
|
||
&& ! cond
|
||
/* 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))
|
||
add_to_mem_set_list (pbi, canon_rtx (reg));
|
||
}
|
||
|
||
if (GET_CODE (reg) == REG
|
||
&& ! (regno_first == FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
|
||
&& ! (regno_first == HARD_FRAME_POINTER_REGNUM
|
||
&& (! reload_completed || frame_pointer_needed))
|
||
#endif
|
||
#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
|
||
&& ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
|
||
#endif
|
||
)
|
||
{
|
||
int some_was_live = 0, some_was_dead = 0;
|
||
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
{
|
||
int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
|
||
if (pbi->local_set)
|
||
{
|
||
/* Order of the set operation matters here since both
|
||
sets may be the same. */
|
||
CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
|
||
if (cond != NULL_RTX
|
||
&& ! REGNO_REG_SET_P (pbi->local_set, i))
|
||
SET_REGNO_REG_SET (pbi->cond_local_set, i);
|
||
else
|
||
SET_REGNO_REG_SET (pbi->local_set, i);
|
||
}
|
||
if (code != CLOBBER)
|
||
SET_REGNO_REG_SET (pbi->new_set, i);
|
||
|
||
some_was_live |= needed_regno;
|
||
some_was_dead |= ! needed_regno;
|
||
}
|
||
|
||
#ifdef HAVE_conditional_execution
|
||
/* Consider conditional death in deciding that the register needs
|
||
a death note. */
|
||
if (some_was_live && ! not_dead
|
||
/* The stack pointer is never dead. Well, not strictly true,
|
||
but it's very difficult to tell from here. Hopefully
|
||
combine_stack_adjustments will fix up the most egregious
|
||
errors. */
|
||
&& regno_first != STACK_POINTER_REGNUM)
|
||
{
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
if (! mark_regno_cond_dead (pbi, i, cond))
|
||
not_dead |= ((unsigned long) 1) << (i - regno_first);
|
||
}
|
||
#endif
|
||
|
||
/* Additional data to record if this is the final pass. */
|
||
if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
|
||
| PROP_DEATH_NOTES | PROP_AUTOINC))
|
||
{
|
||
rtx y;
|
||
int blocknum = pbi->bb->index;
|
||
|
||
y = NULL_RTX;
|
||
if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
|
||
{
|
||
y = pbi->reg_next_use[regno_first];
|
||
|
||
/* The next use is no longer next, since a store intervenes. */
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
pbi->reg_next_use[i] = 0;
|
||
}
|
||
|
||
if (flags & PROP_REG_INFO)
|
||
{
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
{
|
||
/* Count (weighted) references, stores, etc. This counts a
|
||
register twice if it is modified, but that is correct. */
|
||
REG_N_SETS (i) += 1;
|
||
REG_N_REFS (i) += 1;
|
||
REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
|
||
|
||
/* 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 (i) += 1;
|
||
}
|
||
|
||
/* If this is a hard reg, record this function uses the reg. */
|
||
if (regno_first < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
for (i = regno_first; i <= regno_last; i++)
|
||
regs_ever_live[i] = 1;
|
||
}
|
||
else
|
||
{
|
||
/* Keep track of which basic blocks each reg appears in. */
|
||
if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
|
||
REG_BASIC_BLOCK (regno_first) = blocknum;
|
||
else if (REG_BASIC_BLOCK (regno_first) != blocknum)
|
||
REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
|
||
}
|
||
}
|
||
|
||
if (! some_was_dead)
|
||
{
|
||
if (flags & PROP_LOG_LINKS)
|
||
{
|
||
/* 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 >= FIRST_PSEUDO_REGISTER
|
||
|| asm_noperands (PATTERN (y)) < 0))
|
||
LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
|
||
}
|
||
}
|
||
else if (not_dead)
|
||
;
|
||
else if (! some_was_live)
|
||
{
|
||
if (flags & PROP_REG_INFO)
|
||
REG_N_DEATHS (regno_first) += 1;
|
||
|
||
if (flags & PROP_DEATH_NOTES)
|
||
{
|
||
/* 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)
|
||
= alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (flags & PROP_DEATH_NOTES)
|
||
{
|
||
/* 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. */
|
||
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
if (! REGNO_REG_SET_P (pbi->reg_live, i))
|
||
REG_NOTES (insn)
|
||
= alloc_EXPR_LIST (REG_UNUSED,
|
||
gen_rtx_REG (reg_raw_mode[i], i),
|
||
REG_NOTES (insn));
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Mark the register as being dead. */
|
||
if (some_was_live
|
||
/* The stack pointer is never dead. Well, not strictly true,
|
||
but it's very difficult to tell from here. Hopefully
|
||
combine_stack_adjustments will fix up the most egregious
|
||
errors. */
|
||
&& regno_first != STACK_POINTER_REGNUM)
|
||
{
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
|
||
CLEAR_REGNO_REG_SET (pbi->reg_live, i);
|
||
}
|
||
}
|
||
else if (GET_CODE (reg) == REG)
|
||
{
|
||
if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
|
||
pbi->reg_next_use[regno_first] = 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)
|
||
{
|
||
if (flags & PROP_DEATH_NOTES)
|
||
REG_NOTES (insn)
|
||
= alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
|
||
}
|
||
}
|
||
|
||
#ifdef HAVE_conditional_execution
|
||
/* Mark REGNO conditionally dead.
|
||
Return true if the register is now unconditionally dead. */
|
||
|
||
static int
|
||
mark_regno_cond_dead (pbi, regno, cond)
|
||
struct propagate_block_info *pbi;
|
||
int regno;
|
||
rtx cond;
|
||
{
|
||
/* If this is a store to a predicate register, the value of the
|
||
predicate is changing, we don't know that the predicate as seen
|
||
before is the same as that seen after. Flush all dependent
|
||
conditions from reg_cond_dead. This will make all such
|
||
conditionally live registers unconditionally live. */
|
||
if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
|
||
flush_reg_cond_reg (pbi, regno);
|
||
|
||
/* If this is an unconditional store, remove any conditional
|
||
life that may have existed. */
|
||
if (cond == NULL_RTX)
|
||
splay_tree_remove (pbi->reg_cond_dead, regno);
|
||
else
|
||
{
|
||
splay_tree_node node;
|
||
struct reg_cond_life_info *rcli;
|
||
rtx ncond;
|
||
|
||
/* Otherwise this is a conditional set. Record that fact.
|
||
It may have been conditionally used, or there may be a
|
||
subsequent set with a complimentary condition. */
|
||
|
||
node = splay_tree_lookup (pbi->reg_cond_dead, regno);
|
||
if (node == NULL)
|
||
{
|
||
/* The register was unconditionally live previously.
|
||
Record the current condition as the condition under
|
||
which it is dead. */
|
||
rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
|
||
rcli->condition = cond;
|
||
rcli->stores = cond;
|
||
rcli->orig_condition = const0_rtx;
|
||
splay_tree_insert (pbi->reg_cond_dead, regno,
|
||
(splay_tree_value) rcli);
|
||
|
||
SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
|
||
|
||
/* Not unconditionally dead. */
|
||
return 0;
|
||
}
|
||
else
|
||
{
|
||
/* The register was conditionally live previously.
|
||
Add the new condition to the old. */
|
||
rcli = (struct reg_cond_life_info *) node->value;
|
||
ncond = rcli->condition;
|
||
ncond = ior_reg_cond (ncond, cond, 1);
|
||
if (rcli->stores == const0_rtx)
|
||
rcli->stores = cond;
|
||
else if (rcli->stores != const1_rtx)
|
||
rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
|
||
|
||
/* If the register is now unconditionally dead, remove the entry
|
||
in the splay_tree. A register is unconditionally dead if the
|
||
dead condition ncond is true. A register is also unconditionally
|
||
dead if the sum of all conditional stores is an unconditional
|
||
store (stores is true), and the dead condition is identically the
|
||
same as the original dead condition initialized at the end of
|
||
the block. This is a pointer compare, not an rtx_equal_p
|
||
compare. */
|
||
if (ncond == const1_rtx
|
||
|| (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
|
||
splay_tree_remove (pbi->reg_cond_dead, regno);
|
||
else
|
||
{
|
||
rcli->condition = ncond;
|
||
|
||
SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
|
||
|
||
/* Not unconditionally dead. */
|
||
return 0;
|
||
}
|
||
}
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Called from splay_tree_delete for pbi->reg_cond_life. */
|
||
|
||
static void
|
||
free_reg_cond_life_info (value)
|
||
splay_tree_value value;
|
||
{
|
||
struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
|
||
free (rcli);
|
||
}
|
||
|
||
/* Helper function for flush_reg_cond_reg. */
|
||
|
||
static int
|
||
flush_reg_cond_reg_1 (node, data)
|
||
splay_tree_node node;
|
||
void *data;
|
||
{
|
||
struct reg_cond_life_info *rcli;
|
||
int *xdata = (int *) data;
|
||
unsigned int regno = xdata[0];
|
||
|
||
/* Don't need to search if last flushed value was farther on in
|
||
the in-order traversal. */
|
||
if (xdata[1] >= (int) node->key)
|
||
return 0;
|
||
|
||
/* Splice out portions of the expression that refer to regno. */
|
||
rcli = (struct reg_cond_life_info *) node->value;
|
||
rcli->condition = elim_reg_cond (rcli->condition, regno);
|
||
if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
|
||
rcli->stores = elim_reg_cond (rcli->stores, regno);
|
||
|
||
/* If the entire condition is now false, signal the node to be removed. */
|
||
if (rcli->condition == const0_rtx)
|
||
{
|
||
xdata[1] = node->key;
|
||
return -1;
|
||
}
|
||
else if (rcli->condition == const1_rtx)
|
||
abort ();
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
|
||
|
||
static void
|
||
flush_reg_cond_reg (pbi, regno)
|
||
struct propagate_block_info *pbi;
|
||
int regno;
|
||
{
|
||
int pair[2];
|
||
|
||
pair[0] = regno;
|
||
pair[1] = -1;
|
||
while (splay_tree_foreach (pbi->reg_cond_dead,
|
||
flush_reg_cond_reg_1, pair) == -1)
|
||
splay_tree_remove (pbi->reg_cond_dead, pair[1]);
|
||
|
||
CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
|
||
}
|
||
|
||
/* Logical arithmetic on predicate conditions. IOR, NOT and AND.
|
||
For ior/and, the ADD flag determines whether we want to add the new
|
||
condition X to the old one unconditionally. If it is zero, we will
|
||
only return a new expression if X allows us to simplify part of
|
||
OLD, otherwise we return NULL to the caller.
|
||
If ADD is nonzero, we will return a new condition in all cases. The
|
||
toplevel caller of one of these functions should always pass 1 for
|
||
ADD. */
|
||
|
||
static rtx
|
||
ior_reg_cond (old, x, add)
|
||
rtx old, x;
|
||
int add;
|
||
{
|
||
rtx op0, op1;
|
||
|
||
if (GET_RTX_CLASS (GET_CODE (old)) == '<')
|
||
{
|
||
if (GET_RTX_CLASS (GET_CODE (x)) == '<'
|
||
&& REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
|
||
&& REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
|
||
return const1_rtx;
|
||
if (GET_CODE (x) == GET_CODE (old)
|
||
&& REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
|
||
return old;
|
||
if (! add)
|
||
return NULL;
|
||
return gen_rtx_IOR (0, old, x);
|
||
}
|
||
|
||
switch (GET_CODE (old))
|
||
{
|
||
case IOR:
|
||
op0 = ior_reg_cond (XEXP (old, 0), x, 0);
|
||
op1 = ior_reg_cond (XEXP (old, 1), x, 0);
|
||
if (op0 != NULL || op1 != NULL)
|
||
{
|
||
if (op0 == const0_rtx)
|
||
return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
|
||
if (op1 == const0_rtx)
|
||
return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
|
||
if (op0 == const1_rtx || op1 == const1_rtx)
|
||
return const1_rtx;
|
||
if (op0 == NULL)
|
||
op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
|
||
else if (rtx_equal_p (x, op0))
|
||
/* (x | A) | x ~ (x | A). */
|
||
return old;
|
||
if (op1 == NULL)
|
||
op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
|
||
else if (rtx_equal_p (x, op1))
|
||
/* (A | x) | x ~ (A | x). */
|
||
return old;
|
||
return gen_rtx_IOR (0, op0, op1);
|
||
}
|
||
if (! add)
|
||
return NULL;
|
||
return gen_rtx_IOR (0, old, x);
|
||
|
||
case AND:
|
||
op0 = ior_reg_cond (XEXP (old, 0), x, 0);
|
||
op1 = ior_reg_cond (XEXP (old, 1), x, 0);
|
||
if (op0 != NULL || op1 != NULL)
|
||
{
|
||
if (op0 == const1_rtx)
|
||
return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
|
||
if (op1 == const1_rtx)
|
||
return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
|
||
if (op0 == const0_rtx || op1 == const0_rtx)
|
||
return const0_rtx;
|
||
if (op0 == NULL)
|
||
op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
|
||
else if (rtx_equal_p (x, op0))
|
||
/* (x & A) | x ~ x. */
|
||
return op0;
|
||
if (op1 == NULL)
|
||
op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
|
||
else if (rtx_equal_p (x, op1))
|
||
/* (A & x) | x ~ x. */
|
||
return op1;
|
||
return gen_rtx_AND (0, op0, op1);
|
||
}
|
||
if (! add)
|
||
return NULL;
|
||
return gen_rtx_IOR (0, old, x);
|
||
|
||
case NOT:
|
||
op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
|
||
if (op0 != NULL)
|
||
return not_reg_cond (op0);
|
||
if (! add)
|
||
return NULL;
|
||
return gen_rtx_IOR (0, old, x);
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
static rtx
|
||
not_reg_cond (x)
|
||
rtx x;
|
||
{
|
||
enum rtx_code x_code;
|
||
|
||
if (x == const0_rtx)
|
||
return const1_rtx;
|
||
else if (x == const1_rtx)
|
||
return const0_rtx;
|
||
x_code = GET_CODE (x);
|
||
if (x_code == NOT)
|
||
return XEXP (x, 0);
|
||
if (GET_RTX_CLASS (x_code) == '<'
|
||
&& GET_CODE (XEXP (x, 0)) == REG)
|
||
{
|
||
if (XEXP (x, 1) != const0_rtx)
|
||
abort ();
|
||
|
||
return gen_rtx_fmt_ee (reverse_condition (x_code),
|
||
VOIDmode, XEXP (x, 0), const0_rtx);
|
||
}
|
||
return gen_rtx_NOT (0, x);
|
||
}
|
||
|
||
static rtx
|
||
and_reg_cond (old, x, add)
|
||
rtx old, x;
|
||
int add;
|
||
{
|
||
rtx op0, op1;
|
||
|
||
if (GET_RTX_CLASS (GET_CODE (old)) == '<')
|
||
{
|
||
if (GET_RTX_CLASS (GET_CODE (x)) == '<'
|
||
&& GET_CODE (x) == reverse_condition (GET_CODE (old))
|
||
&& REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
|
||
return const0_rtx;
|
||
if (GET_CODE (x) == GET_CODE (old)
|
||
&& REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
|
||
return old;
|
||
if (! add)
|
||
return NULL;
|
||
return gen_rtx_AND (0, old, x);
|
||
}
|
||
|
||
switch (GET_CODE (old))
|
||
{
|
||
case IOR:
|
||
op0 = and_reg_cond (XEXP (old, 0), x, 0);
|
||
op1 = and_reg_cond (XEXP (old, 1), x, 0);
|
||
if (op0 != NULL || op1 != NULL)
|
||
{
|
||
if (op0 == const0_rtx)
|
||
return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
|
||
if (op1 == const0_rtx)
|
||
return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
|
||
if (op0 == const1_rtx || op1 == const1_rtx)
|
||
return const1_rtx;
|
||
if (op0 == NULL)
|
||
op0 = gen_rtx_AND (0, XEXP (old, 0), x);
|
||
else if (rtx_equal_p (x, op0))
|
||
/* (x | A) & x ~ x. */
|
||
return op0;
|
||
if (op1 == NULL)
|
||
op1 = gen_rtx_AND (0, XEXP (old, 1), x);
|
||
else if (rtx_equal_p (x, op1))
|
||
/* (A | x) & x ~ x. */
|
||
return op1;
|
||
return gen_rtx_IOR (0, op0, op1);
|
||
}
|
||
if (! add)
|
||
return NULL;
|
||
return gen_rtx_AND (0, old, x);
|
||
|
||
case AND:
|
||
op0 = and_reg_cond (XEXP (old, 0), x, 0);
|
||
op1 = and_reg_cond (XEXP (old, 1), x, 0);
|
||
if (op0 != NULL || op1 != NULL)
|
||
{
|
||
if (op0 == const1_rtx)
|
||
return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
|
||
if (op1 == const1_rtx)
|
||
return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
|
||
if (op0 == const0_rtx || op1 == const0_rtx)
|
||
return const0_rtx;
|
||
if (op0 == NULL)
|
||
op0 = gen_rtx_AND (0, XEXP (old, 0), x);
|
||
else if (rtx_equal_p (x, op0))
|
||
/* (x & A) & x ~ (x & A). */
|
||
return old;
|
||
if (op1 == NULL)
|
||
op1 = gen_rtx_AND (0, XEXP (old, 1), x);
|
||
else if (rtx_equal_p (x, op1))
|
||
/* (A & x) & x ~ (A & x). */
|
||
return old;
|
||
return gen_rtx_AND (0, op0, op1);
|
||
}
|
||
if (! add)
|
||
return NULL;
|
||
return gen_rtx_AND (0, old, x);
|
||
|
||
case NOT:
|
||
op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
|
||
if (op0 != NULL)
|
||
return not_reg_cond (op0);
|
||
if (! add)
|
||
return NULL;
|
||
return gen_rtx_AND (0, old, x);
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* Given a condition X, remove references to reg REGNO and return the
|
||
new condition. The removal will be done so that all conditions
|
||
involving REGNO are considered to evaluate to false. This function
|
||
is used when the value of REGNO changes. */
|
||
|
||
static rtx
|
||
elim_reg_cond (x, regno)
|
||
rtx x;
|
||
unsigned int regno;
|
||
{
|
||
rtx op0, op1;
|
||
|
||
if (GET_RTX_CLASS (GET_CODE (x)) == '<')
|
||
{
|
||
if (REGNO (XEXP (x, 0)) == regno)
|
||
return const0_rtx;
|
||
return x;
|
||
}
|
||
|
||
switch (GET_CODE (x))
|
||
{
|
||
case AND:
|
||
op0 = elim_reg_cond (XEXP (x, 0), regno);
|
||
op1 = elim_reg_cond (XEXP (x, 1), regno);
|
||
if (op0 == const0_rtx || op1 == const0_rtx)
|
||
return const0_rtx;
|
||
if (op0 == const1_rtx)
|
||
return op1;
|
||
if (op1 == const1_rtx)
|
||
return op0;
|
||
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
|
||
return x;
|
||
return gen_rtx_AND (0, op0, op1);
|
||
|
||
case IOR:
|
||
op0 = elim_reg_cond (XEXP (x, 0), regno);
|
||
op1 = elim_reg_cond (XEXP (x, 1), regno);
|
||
if (op0 == const1_rtx || op1 == const1_rtx)
|
||
return const1_rtx;
|
||
if (op0 == const0_rtx)
|
||
return op1;
|
||
if (op1 == const0_rtx)
|
||
return op0;
|
||
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
|
||
return x;
|
||
return gen_rtx_IOR (0, op0, op1);
|
||
|
||
case NOT:
|
||
op0 = elim_reg_cond (XEXP (x, 0), regno);
|
||
if (op0 == const0_rtx)
|
||
return const1_rtx;
|
||
if (op0 == const1_rtx)
|
||
return const0_rtx;
|
||
if (op0 != XEXP (x, 0))
|
||
return not_reg_cond (op0);
|
||
return x;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
#endif /* HAVE_conditional_execution */
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
|
||
/* Try to substitute the auto-inc expression INC as the address inside
|
||
MEM which occurs in INSN. Currently, the address of MEM is an expression
|
||
involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
|
||
that has a single set whose source is a PLUS of INCR_REG and something
|
||
else. */
|
||
|
||
static void
|
||
attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
|
||
struct propagate_block_info *pbi;
|
||
rtx inc, insn, mem, incr, incr_reg;
|
||
{
|
||
int regno = REGNO (incr_reg);
|
||
rtx set = single_set (incr);
|
||
rtx q = SET_DEST (set);
|
||
rtx y = SET_SRC (set);
|
||
int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
|
||
|
||
/* Make sure this reg appears only once in this insn. */
|
||
if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
|
||
return;
|
||
|
||
if (dead_or_set_p (incr, incr_reg)
|
||
/* Mustn't autoinc an eliminable register. */
|
||
&& (regno >= FIRST_PSEUDO_REGISTER
|
||
|| ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
|
||
{
|
||
/* 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 (mem, 0), inc, 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;
|
||
|
||
start_sequence ();
|
||
emit_move_insn (q, incr_reg);
|
||
insns = get_insns ();
|
||
end_sequence ();
|
||
|
||
/* 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. */
|
||
|
||
XEXP (inc, 0) = q;
|
||
validate_change (insn, &XEXP (mem, 0), inc, 1);
|
||
validate_change (incr, &XEXP (y, opnum), 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 (pbi->bb->head == insn)
|
||
pbi->bb->head = insns;
|
||
|
||
/* INCR will become a NOTE and INSN won't contain a
|
||
use of INCR_REG. If a use of INCR_REG 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))) == incr_reg)
|
||
pbi->reg_next_use[regno] = PREV_INSN (insn);
|
||
else
|
||
pbi->reg_next_use[regno] = 0;
|
||
|
||
incr_reg = 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 live, we'll put a REG_DEAD note for it
|
||
on this insn, which is incorrect. */
|
||
SET_REGNO_REG_SET (pbi->reg_live, 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)++;
|
||
|
||
/* Invalidate alias info for Q since we just changed its value. */
|
||
clear_reg_alias_info (q);
|
||
}
|
||
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) = alloc_EXPR_LIST (REG_INC, incr_reg, 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), incr_reg, 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 (REGNO (SET_DEST (set)) == REGNO (incr_reg))
|
||
{
|
||
/* If the original source was dead, it's dead now. */
|
||
rtx note;
|
||
|
||
while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
|
||
{
|
||
remove_note (incr, note);
|
||
if (XEXP (note, 0) != incr_reg)
|
||
CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
|
||
}
|
||
|
||
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_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
|
||
|
||
/* Count the increment as a setting of the register,
|
||
even though it isn't a SET in rtl. */
|
||
REG_N_SETS (regno)++;
|
||
}
|
||
}
|
||
|
||
/* X is a MEM found in INSN. See if we can convert it into an auto-increment
|
||
reference. */
|
||
|
||
static void
|
||
find_auto_inc (pbi, x, insn)
|
||
struct propagate_block_info *pbi;
|
||
rtx x;
|
||
rtx insn;
|
||
{
|
||
rtx addr = XEXP (x, 0);
|
||
HOST_WIDE_INT offset = 0;
|
||
rtx set, y, incr, inc_val;
|
||
int regno;
|
||
int size = GET_MODE_SIZE (GET_MODE (x));
|
||
|
||
if (GET_CODE (insn) == JUMP_INSN)
|
||
return;
|
||
|
||
/* 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)
|
||
return;
|
||
|
||
regno = REGNO (addr);
|
||
|
||
/* Is the next use an increment that might make auto-increment? */
|
||
incr = pbi->reg_next_use[regno];
|
||
if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
|
||
return;
|
||
set = single_set (incr);
|
||
if (set == 0 || GET_CODE (set) != SET)
|
||
return;
|
||
y = SET_SRC (set);
|
||
|
||
if (GET_CODE (y) != PLUS)
|
||
return;
|
||
|
||
if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
|
||
inc_val = XEXP (y, 1);
|
||
else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
|
||
inc_val = XEXP (y, 0);
|
||
else
|
||
return;
|
||
|
||
if (GET_CODE (inc_val) == CONST_INT)
|
||
{
|
||
if (HAVE_POST_INCREMENT
|
||
&& (INTVAL (inc_val) == size && offset == 0))
|
||
attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
|
||
incr, addr);
|
||
else if (HAVE_POST_DECREMENT
|
||
&& (INTVAL (inc_val) == -size && offset == 0))
|
||
attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
|
||
incr, addr);
|
||
else if (HAVE_PRE_INCREMENT
|
||
&& (INTVAL (inc_val) == size && offset == size))
|
||
attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
|
||
incr, addr);
|
||
else if (HAVE_PRE_DECREMENT
|
||
&& (INTVAL (inc_val) == -size && offset == -size))
|
||
attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
|
||
incr, addr);
|
||
else if (HAVE_POST_MODIFY_DISP && offset == 0)
|
||
attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
|
||
gen_rtx_PLUS (Pmode,
|
||
addr,
|
||
inc_val)),
|
||
insn, x, incr, addr);
|
||
}
|
||
else if (GET_CODE (inc_val) == REG
|
||
&& ! reg_set_between_p (inc_val, PREV_INSN (insn),
|
||
NEXT_INSN (incr)))
|
||
|
||
{
|
||
if (HAVE_POST_MODIFY_REG && offset == 0)
|
||
attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
|
||
gen_rtx_PLUS (Pmode,
|
||
addr,
|
||
inc_val)),
|
||
insn, x, incr, addr);
|
||
}
|
||
}
|
||
|
||
#endif /* AUTO_INC_DEC */
|
||
|
||
static void
|
||
mark_used_reg (pbi, reg, cond, insn)
|
||
struct propagate_block_info *pbi;
|
||
rtx reg;
|
||
rtx cond ATTRIBUTE_UNUSED;
|
||
rtx insn;
|
||
{
|
||
unsigned int regno_first, regno_last, i;
|
||
int some_was_live, some_was_dead, some_not_set;
|
||
|
||
regno_last = regno_first = REGNO (reg);
|
||
if (regno_first < FIRST_PSEUDO_REGISTER)
|
||
regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
|
||
|
||
/* Find out if any of this register is live after this instruction. */
|
||
some_was_live = some_was_dead = 0;
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
{
|
||
int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
|
||
some_was_live |= needed_regno;
|
||
some_was_dead |= ! needed_regno;
|
||
}
|
||
|
||
/* Find out if any of the register was set this insn. */
|
||
some_not_set = 0;
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
|
||
|
||
if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
|
||
{
|
||
/* Record where each reg is used, so when the reg is set we know
|
||
the next insn that uses it. */
|
||
pbi->reg_next_use[regno_first] = insn;
|
||
}
|
||
|
||
if (pbi->flags & PROP_REG_INFO)
|
||
{
|
||
if (regno_first < FIRST_PSEUDO_REGISTER)
|
||
{
|
||
/* 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.
|
||
|
||
Otherwise, record that this function uses this register. */
|
||
/* ??? The PPC backend tries to "eliminate" on the pic
|
||
register to itself. This should be fixed. In the mean
|
||
time, hack around it. */
|
||
|
||
if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
|
||
&& (regno_first == FRAME_POINTER_REGNUM
|
||
|| regno_first == ARG_POINTER_REGNUM)))
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
regs_ever_live[i] = 1;
|
||
}
|
||
else
|
||
{
|
||
/* Keep track of which basic block each reg appears in. */
|
||
|
||
int blocknum = pbi->bb->index;
|
||
if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
|
||
REG_BASIC_BLOCK (regno_first) = blocknum;
|
||
else if (REG_BASIC_BLOCK (regno_first) != blocknum)
|
||
REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
|
||
|
||
/* Count (weighted) number of uses of each reg. */
|
||
REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
|
||
REG_N_REFS (regno_first)++;
|
||
}
|
||
}
|
||
|
||
/* 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 ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
|
||
&& some_was_dead
|
||
&& some_not_set)
|
||
{
|
||
/* Check for the case where the register dying partially
|
||
overlaps the register set by this insn. */
|
||
if (regno_first != regno_last)
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
|
||
|
||
/* If none of the words in X is needed, make a REG_DEAD note.
|
||
Otherwise, we must make partial REG_DEAD notes. */
|
||
if (! some_was_live)
|
||
{
|
||
if ((pbi->flags & PROP_DEATH_NOTES)
|
||
&& ! find_regno_note (insn, REG_DEAD, regno_first))
|
||
REG_NOTES (insn)
|
||
= alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
|
||
|
||
if (pbi->flags & PROP_REG_INFO)
|
||
REG_N_DEATHS (regno_first)++;
|
||
}
|
||
else
|
||
{
|
||
/* Don't make a REG_DEAD note for a part of a register
|
||
that is set in the insn. */
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
if (! REGNO_REG_SET_P (pbi->reg_live, i)
|
||
&& ! dead_or_set_regno_p (insn, i))
|
||
REG_NOTES (insn)
|
||
= alloc_EXPR_LIST (REG_DEAD,
|
||
gen_rtx_REG (reg_raw_mode[i], i),
|
||
REG_NOTES (insn));
|
||
}
|
||
}
|
||
|
||
/* Mark the register as being live. */
|
||
for (i = regno_first; i <= regno_last; ++i)
|
||
{
|
||
SET_REGNO_REG_SET (pbi->reg_live, i);
|
||
|
||
#ifdef HAVE_conditional_execution
|
||
/* If this is a conditional use, record that fact. If it is later
|
||
conditionally set, we'll know to kill the register. */
|
||
if (cond != NULL_RTX)
|
||
{
|
||
splay_tree_node node;
|
||
struct reg_cond_life_info *rcli;
|
||
rtx ncond;
|
||
|
||
if (some_was_live)
|
||
{
|
||
node = splay_tree_lookup (pbi->reg_cond_dead, i);
|
||
if (node == NULL)
|
||
{
|
||
/* The register was unconditionally live previously.
|
||
No need to do anything. */
|
||
}
|
||
else
|
||
{
|
||
/* The register was conditionally live previously.
|
||
Subtract the new life cond from the old death cond. */
|
||
rcli = (struct reg_cond_life_info *) node->value;
|
||
ncond = rcli->condition;
|
||
ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
|
||
|
||
/* If the register is now unconditionally live,
|
||
remove the entry in the splay_tree. */
|
||
if (ncond == const0_rtx)
|
||
splay_tree_remove (pbi->reg_cond_dead, i);
|
||
else
|
||
{
|
||
rcli->condition = ncond;
|
||
SET_REGNO_REG_SET (pbi->reg_cond_reg,
|
||
REGNO (XEXP (cond, 0)));
|
||
}
|
||
}
|
||
}
|
||
else
|
||
{
|
||
/* The register was not previously live at all. Record
|
||
the condition under which it is still dead. */
|
||
rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
|
||
rcli->condition = not_reg_cond (cond);
|
||
rcli->stores = const0_rtx;
|
||
rcli->orig_condition = const0_rtx;
|
||
splay_tree_insert (pbi->reg_cond_dead, i,
|
||
(splay_tree_value) rcli);
|
||
|
||
SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
|
||
}
|
||
}
|
||
else if (some_was_live)
|
||
{
|
||
/* The register may have been conditionally live previously, but
|
||
is now unconditionally live. Remove it from the conditionally
|
||
dead list, so that a conditional set won't cause us to think
|
||
it dead. */
|
||
splay_tree_remove (pbi->reg_cond_dead, i);
|
||
}
|
||
#endif
|
||
}
|
||
}
|
||
|
||
/* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
|
||
This is done assuming the registers needed from X are those that
|
||
have 1-bits in PBI->REG_LIVE.
|
||
|
||
INSN is the containing instruction. If INSN is dead, this function
|
||
is not called. */
|
||
|
||
static void
|
||
mark_used_regs (pbi, x, cond, insn)
|
||
struct propagate_block_info *pbi;
|
||
rtx x, cond, insn;
|
||
{
|
||
RTX_CODE code;
|
||
int regno;
|
||
int flags = pbi->flags;
|
||
|
||
retry:
|
||
if (!x)
|
||
return;
|
||
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:
|
||
pbi->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 (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
|
||
return;
|
||
|
||
case MEM:
|
||
/* Don't bother watching stores to mems if this is not the
|
||
final pass. We'll not be deleting dead stores this round. */
|
||
if (optimize && (flags & PROP_SCAN_DEAD_CODE))
|
||
{
|
||
/* 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 = pbi->mem_set_list;
|
||
rtx prev = NULL_RTX;
|
||
rtx next;
|
||
|
||
while (temp)
|
||
{
|
||
next = XEXP (temp, 1);
|
||
if (anti_dependence (XEXP (temp, 0), x))
|
||
{
|
||
/* Splice temp out of the list. */
|
||
if (prev)
|
||
XEXP (prev, 1) = next;
|
||
else
|
||
pbi->mem_set_list = next;
|
||
free_EXPR_LIST_node (temp);
|
||
pbi->mem_set_list_len--;
|
||
}
|
||
else
|
||
prev = temp;
|
||
temp = next;
|
||
}
|
||
}
|
||
|
||
/* 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 (pbi, insn);
|
||
}
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
if (flags & PROP_AUTOINC)
|
||
find_auto_inc (pbi, x, insn);
|
||
#endif
|
||
break;
|
||
|
||
case SUBREG:
|
||
#ifdef CLASS_CANNOT_CHANGE_MODE
|
||
if (GET_CODE (SUBREG_REG (x)) == REG
|
||
&& REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
|
||
&& CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
|
||
GET_MODE (SUBREG_REG (x))))
|
||
REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
|
||
#endif
|
||
|
||
/* While we're here, optimize this case. */
|
||
x = SUBREG_REG (x);
|
||
if (GET_CODE (x) != REG)
|
||
goto retry;
|
||
/* Fall through. */
|
||
|
||
case REG:
|
||
/* See a register other than being set => mark it as needed. */
|
||
mark_used_reg (pbi, x, cond, insn);
|
||
return;
|
||
|
||
case SET:
|
||
{
|
||
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 (flags & PROP_AUTOINC)
|
||
find_auto_inc (pbi, testreg, insn);
|
||
#endif
|
||
mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
|
||
mark_used_regs (pbi, SET_SRC (x), cond, 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)
|
||
{
|
||
#ifdef CLASS_CANNOT_CHANGE_MODE
|
||
if (GET_CODE (testreg) == SUBREG
|
||
&& GET_CODE (SUBREG_REG (testreg)) == REG
|
||
&& REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
|
||
&& CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
|
||
GET_MODE (testreg)))
|
||
REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
|
||
#endif
|
||
|
||
/* 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_BYTES (SUBREG_REG (testreg))
|
||
+ UNITS_PER_WORD - 1) / UNITS_PER_WORD
|
||
> (REG_BYTES (testreg)
|
||
+ UNITS_PER_WORD - 1) / UNITS_PER_WORD))
|
||
;
|
||
else
|
||
mark_dest = 1;
|
||
|
||
testreg = XEXP (testreg, 0);
|
||
}
|
||
|
||
/* If this is a store into a register or group of registers,
|
||
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
|
||
))
|
||
{
|
||
if (mark_dest)
|
||
mark_used_regs (pbi, SET_DEST (x), cond, insn);
|
||
mark_used_regs (pbi, SET_SRC (x), cond, insn);
|
||
return;
|
||
}
|
||
}
|
||
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))
|
||
{
|
||
free_EXPR_LIST_list (&pbi->mem_set_list);
|
||
pbi->mem_set_list_len = 0;
|
||
}
|
||
|
||
/* 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 (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
|
||
}
|
||
break;
|
||
}
|
||
|
||
case COND_EXEC:
|
||
if (cond != NULL_RTX)
|
||
abort ();
|
||
|
||
mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
|
||
|
||
cond = COND_EXEC_TEST (x);
|
||
x = COND_EXEC_CODE (x);
|
||
goto retry;
|
||
|
||
case PHI:
|
||
/* We _do_not_ want to scan operands of phi nodes. Operands of
|
||
a phi function are evaluated only when control reaches this
|
||
block along a particular edge. Therefore, regs that appear
|
||
as arguments to phi should not be added to the global live at
|
||
start. */
|
||
return;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* Recursively scan the operands of this expression. */
|
||
|
||
{
|
||
const char * const fmt = GET_RTX_FORMAT (code);
|
||
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 (pbi, XEXP (x, i), cond, insn);
|
||
}
|
||
else if (fmt[i] == 'E')
|
||
{
|
||
int j;
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
#ifdef AUTO_INC_DEC
|
||
|
||
static int
|
||
try_pre_increment_1 (pbi, insn)
|
||
struct propagate_block_info *pbi;
|
||
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 = pbi->reg_next_use[regno];
|
||
if (y != 0
|
||
&& SET_DEST (x) != stack_pointer_rtx
|
||
&& 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. */
|
||
propagate_block_delete_insn (pbi->bb, insn);
|
||
|
||
/* 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_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
|
||
REG_N_SETS (regno)++;
|
||
}
|
||
|
||
/* Flush any remembered memories depending on the value of
|
||
the incremented register. */
|
||
invalidate_mems_from_set (pbi, SET_DEST (x));
|
||
|
||
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;
|
||
{
|
||
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) (size_t) 1))
|
||
{
|
||
use = find_use_as_address (PATTERN (insn), reg, -amount);
|
||
do_post = 1;
|
||
}
|
||
|
||
if (use == 0 || use == (rtx) (size_t) 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) = alloc_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)
|
||
rtx x;
|
||
rtx reg;
|
||
HOST_WIDE_INT plusconst;
|
||
{
|
||
enum rtx_code code = GET_CODE (x);
|
||
const char * const fmt = GET_RTX_FORMAT (code);
|
||
int i;
|
||
rtx value = 0;
|
||
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) (size_t) 1;
|
||
}
|
||
|
||
if (x == reg)
|
||
return (rtx) (size_t) 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) (size_t) 1;
|
||
}
|
||
else if (fmt[i] == 'E')
|
||
{
|
||
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) (size_t) 1;
|
||
}
|
||
}
|
||
}
|
||
|
||
return value;
|
||
}
|
||
|
||
/* Write information about registers and basic blocks into FILE.
|
||
This is part of making a debugging dump. */
|
||
|
||
void
|
||
dump_regset (r, outf)
|
||
regset r;
|
||
FILE *outf;
|
||
{
|
||
int i;
|
||
if (r == NULL)
|
||
{
|
||
fputs (" (nil)", outf);
|
||
return;
|
||
}
|
||
|
||
EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
|
||
{
|
||
fprintf (outf, " %d", i);
|
||
if (i < FIRST_PSEUDO_REGISTER)
|
||
fprintf (outf, " [%s]",
|
||
reg_names[i]);
|
||
});
|
||
}
|
||
|
||
/* Print a human-reaable representation of R on the standard error
|
||
stream. This function is designed to be used from within the
|
||
debugger. */
|
||
|
||
void
|
||
debug_regset (r)
|
||
regset r;
|
||
{
|
||
dump_regset (r, stderr);
|
||
putc ('\n', stderr);
|
||
}
|
||
|
||
/* 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 ATTRIBUTE_UNUSED;
|
||
int loop_step ATTRIBUTE_UNUSED;
|
||
{
|
||
allocate_reg_life_data ();
|
||
update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
|
||
}
|
||
|
||
/* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
|
||
blocks. If BLOCKS is NULL, assume the universal set. Returns a count
|
||
of the number of registers that died. */
|
||
|
||
int
|
||
count_or_remove_death_notes (blocks, kill)
|
||
sbitmap blocks;
|
||
int kill;
|
||
{
|
||
int i, count = 0;
|
||
|
||
for (i = n_basic_blocks - 1; i >= 0; --i)
|
||
{
|
||
basic_block bb;
|
||
rtx insn;
|
||
|
||
if (blocks && ! TEST_BIT (blocks, i))
|
||
continue;
|
||
|
||
bb = BASIC_BLOCK (i);
|
||
|
||
for (insn = bb->head;; insn = NEXT_INSN (insn))
|
||
{
|
||
if (INSN_P (insn))
|
||
{
|
||
rtx *pprev = ®_NOTES (insn);
|
||
rtx link = *pprev;
|
||
|
||
while (link)
|
||
{
|
||
switch (REG_NOTE_KIND (link))
|
||
{
|
||
case REG_DEAD:
|
||
if (GET_CODE (XEXP (link, 0)) == REG)
|
||
{
|
||
rtx reg = XEXP (link, 0);
|
||
int n;
|
||
|
||
if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
|
||
n = 1;
|
||
else
|
||
n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
|
||
count += n;
|
||
}
|
||
/* Fall through. */
|
||
|
||
case REG_UNUSED:
|
||
if (kill)
|
||
{
|
||
rtx next = XEXP (link, 1);
|
||
free_EXPR_LIST_node (link);
|
||
*pprev = link = next;
|
||
break;
|
||
}
|
||
/* Fall through. */
|
||
|
||
default:
|
||
pprev = &XEXP (link, 1);
|
||
link = *pprev;
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (insn == bb->end)
|
||
break;
|
||
}
|
||
}
|
||
|
||
return count;
|
||
}
|
||
/* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
|
||
if blocks is NULL. */
|
||
|
||
static void
|
||
clear_log_links (blocks)
|
||
sbitmap blocks;
|
||
{
|
||
rtx insn;
|
||
int i;
|
||
|
||
if (!blocks)
|
||
{
|
||
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
|
||
if (INSN_P (insn))
|
||
free_INSN_LIST_list (&LOG_LINKS (insn));
|
||
}
|
||
else
|
||
EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
|
||
{
|
||
basic_block bb = BASIC_BLOCK (i);
|
||
|
||
for (insn = bb->head; insn != NEXT_INSN (bb->end);
|
||
insn = NEXT_INSN (insn))
|
||
if (INSN_P (insn))
|
||
free_INSN_LIST_list (&LOG_LINKS (insn));
|
||
});
|
||
}
|
||
|
||
/* Given a register bitmap, turn on the bits in a HARD_REG_SET that
|
||
correspond to the hard registers, if any, set in that map. This
|
||
could be done far more efficiently by having all sorts of special-cases
|
||
with moving single words, but probably isn't worth the trouble. */
|
||
|
||
void
|
||
reg_set_to_hard_reg_set (to, from)
|
||
HARD_REG_SET *to;
|
||
bitmap from;
|
||
{
|
||
int i;
|
||
|
||
EXECUTE_IF_SET_IN_BITMAP
|
||
(from, 0, i,
|
||
{
|
||
if (i >= FIRST_PSEUDO_REGISTER)
|
||
return;
|
||
SET_HARD_REG_BIT (*to, i);
|
||
});
|
||
}
|