cprop.cc

/* Global constant/copy propagation for RTL.
   Copyright (C) 1997-2024 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "rtl.h"
#include "rtlanal.h"
#include "cfghooks.h"
#include "df.h"
#include "insn-config.h"
#include "memmodel.h"
#include "emit-rtl.h"
#include "recog.h"
#include "diagnostic-core.h"
#include "toplev.h"
#include "cfgrtl.h"
#include "cfganal.h"
#include "lcm.h"
#include "cfgcleanup.h"
#include "cselib.h"
#include "intl.h"
#include "tree-pass.h"
#include "dbgcnt.h"
#include "cfgloop.h"
#include "gcse.h"


/* An obstack for our working variables.  */
static struct obstack cprop_obstack;

/* Occurrence of an expression.
   There is one per basic block.  If a pattern appears more than once the
   last appearance is used.  */

struct cprop_occr
{
  /* Next occurrence of this expression.  */
  struct cprop_occr *next;
  /* The insn that computes the expression.  */
  rtx_insn *insn;
};

/* Hash table entry for assignment expressions.  */

struct cprop_expr
{
  /* The expression (DEST := SRC).  */
  rtx dest;
  rtx src;

  /* Index in the available expression bitmaps.  */
  int bitmap_index;