ifcvt.c: New file.

        * ifcvt.c: New file.
        * Makefile.in (OBJS): Add it.
        (ifcvt.o): New target.
        * jump.c (jump_optimize_1): Remove all code related to if-conversion,
        and conditional arithmetic.
        (find_insert_position): Remove.
        * timevar.def (TV_IFCVT, TV_IFCVT2): New.
        * toplev.c (DFI_ce, DFI_ce2): New.
        (dump_file): Add ce and ce2 dumps.
        (rest_of_compilation): Run if_convert a couple o times.  Set
        cse_not_expected after cse2.  Don't set no_new_pseudos until
        after sched1 or recompute_reg_usage.

From-SVN: r33547

gcc/ChangeLog

 2000-04-30  Richard Henderson  <rth@cygnus.com>
 
+	* ifcvt.c: New file.
+	* Makefile.in (OBJS): Add it.
+	(ifcvt.o): New target.
+	* jump.c (jump_optimize_1): Remove all code related to if-conversion, 
+	and conditional arithmetic.
+	(find_insert_position): Remove.
+	* timevar.def (TV_IFCVT, TV_IFCVT2): New.
+	* toplev.c (DFI_ce, DFI_ce2): New.
+	(dump_file): Add ce and ce2 dumps.
+	(rest_of_compilation): Run if_convert a couple o times.  Set
+	cse_not_expected after cse2.  Don't set no_new_pseudos until
+	after sched1 or recompute_reg_usage.
+
+2000-04-30  Richard Henderson  <rth@cygnus.com>
+
 	* config/alpha/t-crtbe (crtbegin.o): Add "-I.".
 	(crtend.o, crtbeginS.o, crtendS.o): Likewise.
 

gcc/Makefile.in

@@ -684,7 +684,7 @@ OBJS = diagnostic.o \
  profile.o insn-attrtab.o $(out_object_file) $(EXTRA_OBJS) convert.o \
  mbchar.o dyn-string.o splay-tree.o graph.o sbitmap.o resource.o hash.o \
  predict.o lists.o ggc-common.o $(GGC) simplify-rtx.o ssa.o bb-reorder.o \
- sibcall.o conflict.o timevar.o
+ sibcall.o conflict.o timevar.o ifcvt.o
 
 # GEN files are listed separately, so they can be built before doing parallel
 #  makes for cc1 or cc1plus.  Otherwise sequent parallel make attempts to load
@@ -1663,6 +1663,9 @@ timevar.o : timevar.c $(CONFIG_H) system.h $(TIMEVAR_H) flags.h
 regrename.o : regrename.c $(CONFIG_H) system.h $(RTL_H) $(TREE_H) flags.h \
    insn-config.h $(BASIC_BLOCK_H) $(REGS_H) hard-reg-set.h output.h \
    $(RECOG_H) function.h resource.h
+ifcvt.o : ifcvt.c $(CONFIG_H) system.h $(RTL_H) $(REGS_H) \
+   flags.h insn-config.h function.h $(RECOG_H) $(BASIC_BLOCK_H) $(EXPR_H) \
+   output.h
 $(out_object_file): $(out_file) $(CONFIG_H) $(TREE_H) $(GGC_H) \
    $(RTL_H) $(REGS_H) hard-reg-set.h real.h insn-config.h conditions.h \
    insn-flags.h output.h insn-attr.h insn-codes.h system.h toplev.h function.h

gcc/ifcvt.c

+/* If-conversion support.
+   Copyright (C) 2000 Free Software Foundation, Inc.
+
+   This file is part of GNU CC.
+
+   GNU CC is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   GNU CC is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GNU CC; see the file COPYING.  If not, write to
+   the Free Software Foundation, 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "config.h"
+#include "system.h"
+
+#include "rtl.h"
+#include "regs.h"
+#include "function.h"
+#include "flags.h"
+#include "insn-config.h"
+#include "recog.h"
+#include "basic-block.h"
+#include "expr.h"
+#include "output.h"
+#include "hard-reg-set.h"
+#include "tm_p.h"
+
+
+#ifndef HAVE_conditional_execution
+#define HAVE_conditional_execution 0
+#endif
+#ifndef HAVE_conditional_move
+#define HAVE_conditional_move 0
+#endif
+#ifndef HAVE_incscc
+#define HAVE_incscc 0
+#endif
+#ifndef HAVE_decscc
+#define HAVE_decscc 0
+#endif
+
+#ifndef MAX_CONDITIONAL_EXECUTE
+#define MAX_CONDITIONAL_EXECUTE   (BRANCH_COST + 1)
+#endif
+
+#define EDGE_COMPLEX	(EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH)
+
+#define NULL_EDGE	((struct edge_def *)NULL)
+#define NULL_BLOCK	((struct basic_block_def *)NULL)
+
+/* # of IF-THEN or IF-THEN-ELSE blocks we looked at  */
+static int num_possible_if_blocks;
+
+/* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
+   execution.  */
+static int num_updated_if_blocks;
+
+/* # of basic blocks that were removed.  */
+static int num_removed_blocks;
+
+/* The post-dominator relation on the original block numbers.  */
+static sbitmap *post_dominators;
+
+/* Forward references.  */
+static int count_bb_insns		PARAMS ((basic_block));
+static rtx first_active_insn		PARAMS ((basic_block));
+static int last_active_insn_p		PARAMS ((basic_block, rtx));
+
+static int cond_exec_process_insns	PARAMS ((rtx, rtx, rtx, int));
+static rtx cond_exec_get_condition	PARAMS ((rtx));
+static int cond_exec_process_if_block	PARAMS ((basic_block, basic_block,
+						 basic_block, basic_block));
+
+static rtx noce_get_condition		PARAMS ((rtx, rtx *));
+static int noce_process_if_block	PARAMS ((basic_block, basic_block,
+						 basic_block, basic_block));
+
+static int process_if_block		PARAMS ((basic_block, basic_block,
+						 basic_block, basic_block));
+static void merge_if_block		PARAMS ((basic_block, basic_block,
+						 basic_block, basic_block));
+
+static int find_if_header		PARAMS ((basic_block));
+static int find_if_block		PARAMS ((basic_block, edge, edge));
+static int find_if_case_1		PARAMS ((basic_block, edge, edge));
+static int find_if_case_2		PARAMS ((basic_block, edge, edge));
+static int find_memory			PARAMS ((rtx *, void *));
+static int dead_or_predicable		PARAMS ((basic_block, basic_block,
+						 basic_block, rtx, int));
+
+/* Abuse the basic_block AUX field to store the original block index,
+   as well as a flag indicating that the block should be rescaned for
+   life analysis.  */
+
+#define SET_ORIG_INDEX(BB,I)	((BB)->aux = (void *)((size_t)(I) << 1))
+#define ORIG_INDEX(BB)		((size_t)(BB)->aux >> 1)
+#define SET_UPDATE_LIFE(BB)	((BB)->aux = (void *)((size_t)(BB)->aux | 1))
+#define UPDATE_LIFE(BB)		((size_t)(BB)->aux & 1)
+
+
+/* Count the number of non-jump active insns in BB.  */
+
+static int
+count_bb_insns (bb)
+     basic_block bb;
+{
+  int count = 0;
+  rtx insn = bb->head;
+
+  while (1)
+    {
+      if (GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == INSN)
+	count++;
+
+      if (insn == bb->end)
+	break;
+      insn = NEXT_INSN (insn);
+    }
+
+  return count;
+}
+
+/* Return the first non-jump active insn in the basic block.  */
+
+static rtx
+first_active_insn (bb)
+     basic_block bb;
+{
+  rtx insn = bb->head;
+
+  if (GET_CODE (insn) == CODE_LABEL)
+    {
+      if (insn == bb->end)
+	return NULL_RTX;
+      insn = NEXT_INSN (insn);
+    }
+
+  while (GET_CODE (insn) == NOTE)
+    {
+      if (insn == bb->end)
+	return NULL_RTX;
+      insn = NEXT_INSN (insn);
+    }
+
+  if (GET_CODE (insn) == JUMP_INSN)
+    return NULL_RTX;
+
+  return insn;
+}
+
+/* Return true if INSN is the last active non-jump insn in BB.  */
+
+static int
+last_active_insn_p (bb, insn)
+     basic_block bb;
+     rtx insn;
+{
+  do
+    {
+      if (insn == bb->end)
+	return TRUE;
+      insn = NEXT_INSN (insn);
+    }
+  while (GET_CODE (insn) == NOTE);
+
+  return GET_CODE (insn) == JUMP_INSN;
+}
+
+/* Go through a bunch of insns, converting them to conditional
+   execution format if possible.  Return TRUE if all of the non-note
+   insns were processed.  */
+
+static int
+cond_exec_process_insns (start, end, test, mod_ok)
+     rtx start;			/* first insn to look at */
+     rtx end;			/* last insn to look at */
+     rtx test;			/* conditional execution test */
+     int mod_ok;		/* true if modifications ok last insn.  */
+{
+  int must_be_last = FALSE;
+  rtx insn;
+
+  for (insn = start; ; insn = NEXT_INSN (insn))
+    {
+      if (GET_CODE (insn) == NOTE)
+	goto insn_done;
+
+      if (GET_CODE (insn) != INSN && GET_CODE (insn) != CALL_INSN)
+	abort ();
+
+      /* Last insn wasn't last?  */
+      if (must_be_last)
+	return FALSE;
+
+      if (modified_in_p (test, insn))
+	{
+	  if (!mod_ok)
+	    return FALSE;
+	  must_be_last = TRUE;
+	}
+
+      /* Now build the conditional form of the instruction.  */
+      validate_change (insn, &PATTERN (insn),
+		       gen_rtx_COND_EXEC (VOIDmode, copy_rtx (test),
+					  PATTERN (insn)), 1);
+
+    insn_done:
+      if (insn == end)
+	break;
+    }
+
+  return TRUE;
+}
+
+/* Return the condition for a jump.  Do not do any special processing.  */
+
+static rtx
+cond_exec_get_condition (jump)
+     rtx jump;
+{
+  rtx test_if, cond;
+
+  if (condjump_p (jump))
+    test_if = SET_SRC (PATTERN (jump));
+  else if (condjump_in_parallel_p (jump))
+    test_if = SET_SRC (XVECEXP (PATTERN (jump), 0, 0));
+  else
+    return NULL_RTX;
+  cond = XEXP (test_if, 0);
+
+  /* If this branches to JUMP_LABEL when the condition is false,
+     reverse the condition.  */
+  if (GET_CODE (XEXP (test_if, 2)) == LABEL_REF
+      && XEXP (XEXP (test_if, 2), 0) == JUMP_LABEL (jump))
+    cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
+			   GET_MODE (cond), XEXP (cond, 0),
+			   XEXP (cond, 1));
+
+  return cond;
+}
+
+/* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
+   to conditional execution.  Return TRUE if we were successful at
+   converting the the block.  */
+
+static int
+cond_exec_process_if_block (test_bb, then_bb, else_bb, join_bb)
+     basic_block test_bb;	/* Basic block test is in */
+     basic_block then_bb;	/* Basic block for THEN block */
+     basic_block else_bb;	/* Basic block for ELSE block */
+     basic_block join_bb;	/* Basic block the join label is in */
+{
+  rtx test_expr;		/* expression in IF_THEN_ELSE that is tested */
+  rtx then_start;		/* first insn in THEN block */
+  rtx then_end;			/* last insn + 1 in THEN block */
+  rtx else_start;		/* first insn in ELSE block or NULL */
+  rtx else_end;			/* last insn + 1 in ELSE block */
+  int max;			/* max # of insns to convert. */
+  int then_mod_ok;		/* whether conditional mods are ok in THEN */
+  rtx true_expr;		/* test for else block insns */
+  rtx false_expr;		/* test for then block insns */
+  int n_insns;
+
+  /* Find the conditional jump to the ELSE or JOIN part, and isolate
+     the test.  */
+  test_expr = cond_exec_get_condition (test_bb->end);
+  if (! test_expr)
+    return FALSE;
+
+  /* Collect the bounds of where we're to search.  */
+
+  then_start = then_bb->head;
+  then_end = then_bb->end;
+
+  /* Skip a (use (const_int 0)) or branch as the final insn.  */
+  if (GET_CODE (then_end) == INSN
+      && GET_CODE (PATTERN (then_end)) == USE
+      && GET_CODE (XEXP (PATTERN (then_end), 0)) == CONST_INT)
+    then_end = PREV_INSN (then_end);
+  else if (GET_CODE (then_end) == JUMP_INSN)
+    then_end = PREV_INSN (then_end);
+
+  if (else_bb)
+    {
+      /* Skip the ELSE block's label.  */
+      else_start = NEXT_INSN (else_bb->head);
+      else_end = else_bb->end;
+
+      /* Skip a (use (const_int 0)) or branch as the final insn.  */
+      if (GET_CODE (else_end) == INSN
+	  && GET_CODE (PATTERN (else_end)) == USE
+	  && GET_CODE (XEXP (PATTERN (else_end), 0)) == CONST_INT)
+	else_end = PREV_INSN (else_end);
+      else if (GET_CODE (else_end) == JUMP_INSN)
+	else_end = PREV_INSN (else_end);
+    }
+
+  /* How many instructions should we convert in total?  */
+  n_insns = 0;
+  if (else_bb)
+    {
+      max = 2 * MAX_CONDITIONAL_EXECUTE;
+      n_insns = count_bb_insns (else_bb);
+    }
+  else
+    max = MAX_CONDITIONAL_EXECUTE;
+  n_insns += count_bb_insns (then_bb);
+  if (n_insns > max)
+    return FALSE;
+
+  /* Map test_expr/test_jump into the appropriate MD tests to use on
+     the conditionally executed code.  */
+  
+  true_expr = test_expr;
+  false_expr = gen_rtx_fmt_ee (reverse_condition (GET_CODE (true_expr)),
+			       GET_MODE (true_expr), XEXP (true_expr, 0),
+			       XEXP (true_expr, 1));
+
+  /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
+     on then THEN block.  */
+  then_mod_ok = (else_bb == NULL_BLOCK);
+
+  /* Go through the THEN and ELSE blocks converting the insns if possible
+     to conditional execution.  */
+
+  if (then_end
+      && ! cond_exec_process_insns (then_start, then_end,
+				    false_expr, then_mod_ok))
+    goto fail;
+
+  if (else_bb
+      && ! cond_exec_process_insns (else_start, else_end,
+				    true_expr, TRUE))
+    goto fail;
+
+  if (! apply_change_group ())
+    return FALSE;
+
+  /* Conversion succeeded.  */
+  if (rtl_dump_file)
+    fprintf (rtl_dump_file, "%d insn%s converted to conditional execution.\n",
+	     n_insns, (n_insns == 1) ? " was" : "s were");
+
+  /* Merge the blocks!  */
+  merge_if_block (test_bb, then_bb, else_bb, join_bb);
+  return TRUE;
+
+ fail:
+  cancel_changes (0);
+  return FALSE;
+}
+
+/* Used by noce_process_if_block to communicate with its subroutines. 
+
+   The subroutines know that A and B may be evaluated freely.  They
+   know that X is a register.  They should insert new instructions 
+   before cond_earliest.  */
+
+struct noce_if_info
+{
+  rtx insn_a, insn_b;
+  rtx x, a, b;
+  rtx jump, cond, cond_earliest;
+};
+
+static rtx noce_emit_store_flag		PARAMS ((struct noce_if_info *,
+						 rtx, int, int));
+static int noce_try_store_flag		PARAMS ((struct noce_if_info *));
+static int noce_try_store_flag_inc	PARAMS ((struct noce_if_info *));
+static int noce_try_store_flag_constants PARAMS ((struct noce_if_info *));
+static int noce_try_store_flag_mask	PARAMS ((struct noce_if_info *));
+static rtx noce_emit_cmove		PARAMS ((struct noce_if_info *,
+						 rtx, enum rtx_code, rtx,
+						 rtx, rtx, rtx));
+static int noce_try_cmove		PARAMS ((struct noce_if_info *));
+static int noce_try_cmove_arith		PARAMS ((struct noce_if_info *));
+
+/* Helper function for noce_try_store_flag*.  */
+
+static rtx
+noce_emit_store_flag (if_info, x, reversep, normalize)
+     struct noce_if_info *if_info;
+     rtx x;
+     int reversep, normalize;
+{
+  rtx cond = if_info->cond;
+  int cond_complex;
+  enum rtx_code code;
+
+  cond_complex = (! general_operand (XEXP (cond, 0), VOIDmode)
+		  || ! general_operand (XEXP (cond, 1), VOIDmode));
+
+  /* If earliest == jump, or when the condition is complex, try to
+     build the store_flag insn directly.  */
+
+  if (cond_complex)
+    cond = XEXP (SET_SRC (PATTERN (if_info->jump)), 0);
+
+  if ((if_info->cond_earliest == if_info->jump || cond_complex)
+      && (normalize == 0 || STORE_FLAG_VALUE == normalize))
+    {
+      rtx tmp;
+
+      code = GET_CODE (cond);
+      if (reversep)
+	code = reverse_condition (code);
+
+      tmp = gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (cond, 0),
+			    XEXP (cond, 1));
+      tmp = gen_rtx_SET (VOIDmode, x, tmp);
+
+      start_sequence ();
+      tmp = emit_insn (tmp);
+
+      if (recog_memoized (tmp) >= 0)
+	{
+	  tmp = get_insns ();
+	  end_sequence ();
+	  emit_insns (tmp);
+
+	  if_info->cond_earliest = if_info->jump;
+
+	  return x;
+	}
+
+      end_sequence ();
+    }
+
+  /* Don't even try if the comparison operands are weird.  */
+  if (cond_complex)
+    return NULL_RTX;
+
+  code = GET_CODE (cond);
+  if (reversep)
+    code = reverse_condition (code);
+
+  return emit_store_flag (x, code, XEXP (cond, 0),
+			  XEXP (cond, 1), VOIDmode,
+			  (code == LTU || code == LEU
+			   || code == GEU || code == GTU), normalize);
+}
+
+/* Convert "if (test) x = 1; else x = 0".
+
+   Only try 0 and STORE_FLAG_VALUE here.  Other combinations will be
+   tried in noce_try_store_flag_constants after noce_try_cmove has had
+   a go at the conversion.  */
+
+static int
+noce_try_store_flag (if_info)
+     struct noce_if_info *if_info;
+{
+  int reversep;
+  rtx target, seq;
+
+  if (GET_CODE (if_info->b) == CONST_INT
+      && INTVAL (if_info->b) == STORE_FLAG_VALUE
+      && if_info->a == const0_rtx)
+    reversep = 0;
+  else if (if_info->b == const0_rtx
+	   && GET_CODE (if_info->a) == CONST_INT
+	   && INTVAL (if_info->a) == STORE_FLAG_VALUE
+	   && can_reverse_comparison_p (if_info->cond, if_info->jump))
+    reversep = 1;
+  else
+    return FALSE;
+
+  start_sequence ();
+
+  target = noce_emit_store_flag (if_info, if_info->x, reversep, 0);
+  if (target)
+    {
+      if (target != if_info->x)
+	emit_move_insn (if_info->x, target);
+
+      seq = get_insns ();
+      end_sequence ();
+      emit_insns_before (seq, if_info->cond_earliest);
+
+      return TRUE;
+    }
+  else
+    {
+      end_sequence ();
+      return FALSE;
+    }
+}
+
+/* Convert "if (test) x = a; else x = b", for A and B constant.  */
+
+static int
+noce_try_store_flag_constants (if_info)
+     struct noce_if_info *if_info;
+{
+  rtx target, seq;
+  int reversep;
+  HOST_WIDE_INT itrue, ifalse, diff, tmp;
+  int normalize, can_reverse;
+
+  if (! no_new_pseudos
+      && GET_CODE (if_info->a) == CONST_INT
+      && GET_CODE (if_info->b) == CONST_INT)
+    {
+      ifalse = INTVAL (if_info->a);
+      itrue = INTVAL (if_info->b);
+      diff = itrue - ifalse;
+
+      can_reverse = can_reverse_comparison_p (if_info->cond, if_info->jump);
+
+      reversep = 0;
+      if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
+	normalize = 0;
+      else if (ifalse == 0 && exact_log2 (itrue) >= 0
+	       && (STORE_FLAG_VALUE == 1
+		   || BRANCH_COST >= 2))
+	normalize = 1;
+      else if (itrue == 0 && exact_log2 (ifalse) >= 0 && can_reverse
+	       && (STORE_FLAG_VALUE == 1 || BRANCH_COST >= 2))
+	normalize = 1, reversep = 1;
+      else if (itrue == -1
+	       && (STORE_FLAG_VALUE == -1
+		   || BRANCH_COST >= 2))
+	normalize = -1;
+      else if (ifalse == -1 && can_reverse
+	       && (STORE_FLAG_VALUE == -1 || BRANCH_COST >= 2))
+	normalize = -1, reversep = 1;
+      else if ((BRANCH_COST >= 2 && STORE_FLAG_VALUE == -1)
+	       || BRANCH_COST >= 3)
+	normalize = -1;
+      else
+	return FALSE;
+
+      if (reversep)
+      	{
+	  tmp = itrue; itrue = ifalse; ifalse = tmp;
+	  diff = -diff;
+	}
+
+      start_sequence ();
+      target = noce_emit_store_flag (if_info, if_info->x, reversep, normalize);
+      if (! target)
+	{
+	  end_sequence ();
+	  return FALSE;
+	}
+
+      /* if (test) x = 3; else x = 4;
+	 =>   x = 3 + (test == 0);  */
+      if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
+	{
+	  target = expand_binop (GET_MODE (if_info->x),
+				 (diff == STORE_FLAG_VALUE
+				  ? add_optab : sub_optab),
+				 GEN_INT (ifalse), target, if_info->x, 0,
+				 OPTAB_WIDEN);
+	}
+
+      /* if (test) x = 8; else x = 0;
+	 =>   x = (test != 0) << 3;  */
+      else if (ifalse == 0 && (tmp = exact_log2 (itrue)) >= 0)
+	{
+	  target = expand_binop (GET_MODE (if_info->x), ashl_optab,
+				 target, GEN_INT (tmp), if_info->x, 0,
+				 OPTAB_WIDEN);
+	}
+
+      /* if (test) x = -1; else x = b;
+	 =>   x = -(test != 0) | b;  */
+      else if (itrue == -1)
+	{
+	  target = expand_binop (GET_MODE (if_info->x), ior_optab,
+				 target, GEN_INT (ifalse), if_info->x, 0,
+				 OPTAB_WIDEN);
+	}
+
+      /* if (test) x = a; else x = b;
+	 =>   x = (-(test != 0) & (b - a)) + a;  */
+      else
+	{
+	  target = expand_binop (GET_MODE (if_info->x), and_optab,
+				 target, GEN_INT (diff), if_info->x, 0,
+				 OPTAB_WIDEN);
+	  if (target)
+	    target = expand_binop (GET_MODE (if_info->x), add_optab,
+				   target, GEN_INT (ifalse), if_info->x, 0,
+				   OPTAB_WIDEN);
+	}
+
+      if (! target)
+	{
+	  end_sequence ();
+	  return FALSE;
+	}
+
+      if (target != if_info->x)
+	emit_move_insn (if_info->x, target);
+
+      seq = get_insns ();
+      end_sequence ();
+      emit_insns_before (seq, if_info->cond_earliest);
+
+      return TRUE;
+    }
+
+  return FALSE;
+}
+
+/* Convert "if (test) foo++" into "foo += (test != 0)", and 
+   similarly for "foo--".  */
+
+static int
+noce_try_store_flag_inc (if_info)
+     struct noce_if_info *if_info;
+{
+  rtx target, seq;
+  int subtract, normalize;
+
+  if (! no_new_pseudos
+      && (BRANCH_COST >= 2
+	  || HAVE_incscc
+	  || HAVE_decscc)
+      /* Should be no `else' case to worry about.  */
+      && if_info->b == if_info->x
+      && GET_CODE (if_info->a) == PLUS
+      && (XEXP (if_info->a, 1) == const1_rtx
+	  || XEXP (if_info->a, 1) == constm1_rtx)
+      && rtx_equal_p (XEXP (if_info->a, 0), if_info->x)
+      && can_reverse_comparison_p (if_info->cond, if_info->jump))
+    {
+      if (STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
+	subtract = 0, normalize = 0;
+      else if (-STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
+	subtract = 1, normalize = 0;
+      else
+	subtract = 0, normalize = INTVAL (XEXP (if_info->a, 1));
+      
+      start_sequence ();
+
+      target = noce_emit_store_flag (if_info,
+				     gen_reg_rtx (GET_MODE (if_info->x)),
+				     1, normalize);
+
+      if (target)
+	target = expand_binop (GET_MODE (if_info->x),
+			       subtract ? sub_optab : add_optab,
+			       if_info->x, target, if_info->x, 0, OPTAB_WIDEN);
+      if (target)
+	{
+	  if (target != if_info->x)
+	    emit_move_insn (if_info->x, target);
+
+	  seq = get_insns ();
+	  end_sequence ();
+	  emit_insns_before (seq, if_info->cond_earliest);
+
+	  return TRUE;
+	}
+
+      end_sequence ();
+    }
+
+  return FALSE;
+}
+
+/* Convert "if (test) x = 0;" to "x &= -(test == 0);"  */
+
+static int
+noce_try_store_flag_mask (if_info)
+     struct noce_if_info *if_info;
+{
+  rtx target, seq;
+  int reversep;
+
+  reversep = 0;
+  if (! no_new_pseudos
+      && (BRANCH_COST >= 2
+	  || STORE_FLAG_VALUE == -1)
+      && ((if_info->a == const0_rtx
+	   && rtx_equal_p (if_info->b, if_info->x))
+	  || ((reversep = can_reverse_comparison_p (if_info->cond,
+						    if_info->jump))
+	      && if_info->b == const0_rtx
+	      && rtx_equal_p (if_info->a, if_info->x))))
+    {
+      start_sequence ();
+      target = noce_emit_store_flag (if_info,
+				     gen_reg_rtx (GET_MODE (if_info->x)),
+				     reversep, -1);
+      if (target)
+        target = expand_binop (GET_MODE (if_info->x), and_optab,
+			       if_info->x, target, if_info->x, 0,
+			       OPTAB_WIDEN);
+
+      if (target)
+	{
+	  if (target != if_info->x)
+	    emit_move_insn (if_info->x, target);
+
+	  seq = get_insns ();
+	  end_sequence ();
+	  emit_insns_before (seq, if_info->cond_earliest);
+
+	  return TRUE;
+	}
+
+      end_sequence ();
+    }
+
+  return FALSE;
+}
+
+/* Helper function for noce_try_cmove and noce_try_cmove_arith.  */
+
+static rtx
+noce_emit_cmove (if_info, x, code, cmp_a, cmp_b, vfalse, vtrue)
+     struct noce_if_info *if_info;
+     rtx x, cmp_a, cmp_b, vfalse, vtrue;
+     enum rtx_code code;
+{
+  /* If earliest == jump, try to build the cmove insn directly.
+     This is helpful when combine has created some complex condition
+     (like for alpha's cmovlbs) that we can't hope to regenerate
+     through the normal interface.  */
+
+  if (if_info->cond_earliest == if_info->jump)
+    {
+      rtx tmp;
+
+      tmp = gen_rtx_fmt_ee (code, GET_MODE (if_info->cond), cmp_a, cmp_b);
+      tmp = gen_rtx_IF_THEN_ELSE (GET_MODE (x), tmp, vtrue, vfalse);
+      tmp = gen_rtx_SET (VOIDmode, x, tmp);
+
+      start_sequence ();
+      tmp = emit_insn (tmp);
+
+      if (recog_memoized (tmp) >= 0)
+	{
+	  tmp = get_insns ();
+	  end_sequence ();
+	  emit_insns (tmp);
+
+	  return x;
+	}
+
+      end_sequence ();
+    }
+
+  /* Don't even try if the comparison operands are weird.  */
+  if (! general_operand (cmp_a, GET_MODE (cmp_a))
+      || ! general_operand (cmp_b, GET_MODE (cmp_b)))
+    return NULL_RTX;
+
+  return emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode,
+				vtrue, vfalse, GET_MODE (x),
+			        (code == LTU || code == GEU
+				 || code == LEU || code == GTU));
+}
+
+/* Try only simple constants and registers here.  More complex cases
+   are handled in noce_try_cmove_arith after noce_try_store_flag_arith
+   has had a go at it.  */
+
+static int
+noce_try_cmove (if_info)
+     struct noce_if_info *if_info;
+{
+  enum rtx_code code;
+  rtx target, seq;
+
+  if ((CONSTANT_P (if_info->a) || register_operand (if_info->a, VOIDmode))
+      && (CONSTANT_P (if_info->b) || register_operand (if_info->b, VOIDmode)))
+    {
+      start_sequence ();
+
+      code = GET_CODE (if_info->cond);
+      target = noce_emit_cmove (if_info, if_info->x, code,
+				XEXP (if_info->cond, 0),
+				XEXP (if_info->cond, 1),
+				if_info->a, if_info->b);
+
+      if (target)
+	{
+	  if (target != if_info->x)
+	    emit_move_insn (if_info->x, target);
+
+	  seq = get_insns ();
+	  end_sequence ();
+	  emit_insns_before (seq, if_info->cond_earliest);
+	  return TRUE;
+	}
+      else
+	{
+	  end_sequence ();
+	  return FALSE;
+	}
+    }
+
+  return FALSE;
+}
+
+/* Try more complex cases involving conditional_move.  */
+
+static int
+noce_try_cmove_arith (if_info)
+     struct noce_if_info *if_info;
+{
+  rtx a = if_info->a;
+  rtx b = if_info->b;
+  rtx x = if_info->x;
+  rtx insn_a, insn_b;
+  rtx tmp, target;
+  int is_mem = 0;
+  enum rtx_code code;
+
+  /* A conditional move from two memory sources is equivalent to a
+     conditional on their addresses followed by a load.  Don't do this
+     early because it'll screw alias analysis.  Note that we've
+     already checked for no side effects.  */
+  if (! no_new_pseudos && cse_not_expected
+      && GET_CODE (a) == MEM && GET_CODE (b) == MEM
+      && BRANCH_COST >= 5)
+    {
+      a = XEXP (a, 0);
+      b = XEXP (b, 0);
+      x = gen_reg_rtx (Pmode);
+      is_mem = 1;
+    }
+
+  /* ??? We could handle this if we knew that a load from A or B could
+     not fault.  This is true of stack memories or if we've already loaded
+     from the address along the path from ENTRY.  */
+  else if (GET_CODE (a) == MEM || GET_CODE (b) == MEM)
+    return FALSE;
+
+  /* if (test) x = a + b; else x = c - d;
+     => y = a + b;
+        x = c - d;
+	if (test)
+	  x = y;
+  */
+  
+  code = GET_CODE (if_info->cond);
+  insn_a = if_info->insn_a;
+  insn_b = if_info->insn_b;
+
+  /* Possibly rearrange operands to make things come out more natural.  */
+  if (can_reverse_comparison_p (if_info->cond, if_info->jump))
+    {
+      int reversep = 0;
+      if (rtx_equal_p (b, x))
+	reversep = 1;
+      else if (general_operand (b, GET_MODE (b)))
+	reversep = 1;
+
+      if (reversep)
+	{
+	  code = reverse_condition (code);
+	  tmp = a, a = b, b = tmp;
+	  tmp = insn_a, insn_a = insn_b, insn_b = tmp;
+	}
+    }
+
+  start_sequence ();
+
+  /* If either operand is complex, load it into a register first.
+     The best way to do this is to copy the original insn.  In this
+     way we preserve any clobbers etc that the insn may have had.  
+     This is of course not possible in the IS_MEM case.  */
+  if (! general_operand (a, GET_MODE (a)))
+    {
+      rtx set;
+
+      if (no_new_pseudos)
+	goto end_seq_and_fail;
+
+      if (is_mem)
+	{
+	  tmp = gen_reg_rtx (GET_MODE (a));
+	  tmp = emit_insn (gen_rtx_SET (VOIDmode, tmp, a));
+	}
+      else if (! insn_a)
+	goto end_seq_and_fail;
+      else
+	{
+	  a = gen_reg_rtx (GET_MODE (a));
+	  tmp = copy_rtx (insn_a);
+	  set = single_set (tmp);
+	  SET_DEST (set) = a;
+	  tmp = emit_insn (PATTERN (tmp));
+	}
+      if (recog_memoized (tmp) < 0)
+	goto end_seq_and_fail;
+    }
+  if (! general_operand (b, GET_MODE (b)))
+    {
+      rtx set;
+
+      if (no_new_pseudos)
+	goto end_seq_and_fail;
+
+      if (is_mem)
+	{
+          tmp = gen_reg_rtx (GET_MODE (b));
+	  tmp = emit_insn (gen_rtx_SET (VOIDmode, tmp, b));
+	}
+      else if (! insn_b)
+	goto end_seq_and_fail;
+      else
+	{
+          b = gen_reg_rtx (GET_MODE (b));
+	  tmp = copy_rtx (insn_b);
+	  set = single_set (tmp);
+	  SET_DEST (set) = b;
+	  tmp = emit_insn (PATTERN (tmp));
+	}
+      if (recog_memoized (tmp) < 0)
+	goto end_seq_and_fail;
+    }
+
+  target = noce_emit_cmove (if_info, x, code, XEXP (if_info->cond, 0),
+			    XEXP (if_info->cond, 1), a, b);
+
+  if (! target)
+    goto end_seq_and_fail;
+
+  /* If we're handling a memory for above, emit the load now.  */
+  if (is_mem)
+    {
+      tmp = gen_rtx_MEM (GET_MODE (if_info->x), target);
+
+      /* Copy over flags as appropriate.  */
+      if (MEM_VOLATILE_P (if_info->a) || MEM_VOLATILE_P (if_info->b))
+	MEM_VOLATILE_P (tmp) = 1;
+      if (MEM_IN_STRUCT_P (if_info->a) && MEM_IN_STRUCT_P (if_info->b))
+	MEM_IN_STRUCT_P (tmp) = 1;
+      if (MEM_SCALAR_P (if_info->a) && MEM_SCALAR_P (if_info->b))
+	MEM_SCALAR_P (tmp) = 1;
+      if (MEM_ALIAS_SET (if_info->a) == MEM_ALIAS_SET (if_info->b))
+	MEM_ALIAS_SET (tmp) = MEM_ALIAS_SET (if_info->a);
+
+      emit_move_insn (if_info->x, tmp);
+    }
+  else if (target != x)
+    emit_move_insn (x, target);
+
+  tmp = get_insns ();
+  end_sequence ();
+  emit_insns_before (tmp, if_info->cond_earliest);
+  return TRUE;
+
+ end_seq_and_fail:
+  end_sequence ();
+  return FALSE;
+}
+
+/* Look for the condition for the jump first.  We'd prefer to avoid
+   get_condition if we can -- it tries to look back for the contents
+   of an original compare.  On targets that use normal integers for
+   comparisons, e.g. alpha, this is wasteful.  */
+
+static rtx
+noce_get_condition (jump, earliest)
+     rtx jump;
+     rtx *earliest;
+{
+  rtx cond;
+
+  /* If the condition variable is a register and is MODE_INT, accept it.
+     Otherwise, fall back on get_condition.  */
+
+  if (! condjump_p (jump))
+    return NULL_RTX;
+
+  cond = XEXP (SET_SRC (PATTERN (jump)), 0);
+  if (GET_CODE (XEXP (cond, 0)) == REG
+      && GET_MODE_CLASS (GET_MODE (XEXP (cond, 0))) == MODE_INT)
+    {
+      *earliest = jump;
+
+      /* If this branches to JUMP_LABEL when the condition is false,
+	 reverse the condition.  */
+      if (GET_CODE (XEXP (SET_SRC (PATTERN (jump)), 2)) == LABEL_REF
+	  && XEXP (XEXP (SET_SRC (PATTERN (jump)), 2), 0) == JUMP_LABEL (jump))
+	cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
+			       GET_MODE (cond), XEXP (cond, 0),
+			       XEXP (cond, 1));
+    }
+  else
+    cond = get_condition (jump, earliest);
+
+  return cond;
+}
+
+/* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
+   without using conditional execution.  Return TRUE if we were
+   successful at converting the the block.  */
+
+static int
+noce_process_if_block (test_bb, then_bb, else_bb, join_bb)
+     basic_block test_bb;	/* Basic block test is in */
+     basic_block then_bb;	/* Basic block for THEN block */
+     basic_block else_bb;	/* Basic block for ELSE block */
+     basic_block join_bb;	/* Basic block the join label is in */
+{
+  /* We're looking for patterns of the form
+
+     (1) if (...) x = a; else x = b;
+     (2) x = b; if (...) x = a;
+     (3) if (...) x = a;   // as if with an initial x = x.
+
+     The later patterns require jumps to be more expensive.
+
+     ??? For future expansion, look for multiple X in such patterns.  */
+
+  struct noce_if_info if_info;
+  rtx insn_a, insn_b;
+  rtx set_a, set_b;
+  rtx orig_x, x, a, b;
+  rtx jump, cond;
+
+  /* If this is not a standard conditional jump, we can't parse it.  */
+  jump = test_bb->end;
+  cond = noce_get_condition (jump, &if_info.cond_earliest);
+  if (! cond)
+    return FALSE;
+
+  /* We must be comparing objects whose modes imply the size.  */
+  if (GET_MODE (XEXP (cond, 0)) == BLKmode)
+    return FALSE;
+
+  /* Look for one of the potential sets.  */
+  insn_a = first_active_insn (then_bb);
+  if (! insn_a
+      || ! last_active_insn_p (then_bb, insn_a)
+      || (set_a = single_set (insn_a)) == NULL_RTX)
+    return FALSE;
+
+  x = SET_DEST (set_a);
+  a = SET_SRC (set_a);
+
+  /* Look for the other potential set.  Make sure we've got equivalent
+     destinations.  */
+  /* ??? This is overconservative.  Storing to two different mems is
+     as easy as conditionally computing the address.  Storing to a
+     single mem merely requires a scratch memory to use as one of the
+     destination addresses; often the memory immediately below the
+     stack pointer is available for this.  */
+  set_b = NULL_RTX;
+  if (else_bb)
+    {
+      insn_b = first_active_insn (else_bb);
+      if (! insn_b
+	  || ! last_active_insn_p (else_bb, insn_b)
+	  || (set_b = single_set (insn_b)) == NULL_RTX
+	  || ! rtx_equal_p (x, SET_DEST (set_b)))
+	return FALSE;
+    }
+  else
+    {
+      insn_b = prev_nonnote_insn (if_info.cond_earliest);
+      if (! insn_b
+	  || GET_CODE (insn_b) != INSN
+	  || (set_b = single_set (insn_b)) == NULL_RTX
+	  || ! rtx_equal_p (x, SET_DEST (set_b))
+	  || reg_mentioned_p (x, cond))
+	insn_b = set_b = NULL_RTX;
+    }
+  b = (set_b ? SET_SRC (set_b) : x);
+
+  /* Only operate on register destinations, and even then avoid extending
+     the lifetime of hard registers on small register class machines.  */
+  orig_x = x;
+  if (GET_CODE (x) != REG
+      || (SMALL_REGISTER_CLASSES
+	  && REGNO (x) < FIRST_PSEUDO_REGISTER))
+    {
+      if (no_new_pseudos)
+	return FALSE;
+      x = gen_reg_rtx (GET_MODE (x));
+    }
+
+  /* Don't operate on sources that may trap or are volatile.  */
+  if (side_effects_p (a) || side_effects_p (b)
+      || (GET_CODE (a) != MEM && may_trap_p (a))
+      || (GET_CODE (b) != MEM && may_trap_p (b)))
+    return FALSE;
+
+  /* Set up the info block for our subroutines.  */
+  if_info.cond = cond;
+  if_info.jump = jump;
+  if_info.insn_a = insn_a;
+  if_info.insn_b = insn_b;
+  if_info.x = x;
+  if_info.a = a;
+  if_info.b = b;
+
+  /* Try optimizations in some approximation of a useful order.  */
+  /* ??? Should first look to see if X is live incoming at all.  If it
+     isn't, we don't need anything but an unconditional set.  */
+
+  /* Look and see if A and B are really the same.  Avoid creating silly
+     cmove constructs that no one will fix up later.  */
+  if (rtx_equal_p (a, b))
+    {
+      /* If we have an INSN_B, we don't have to create any new rtl.  Just
+	 move the instruction that we already have.  If we don't have an
+	 INSN_B, that means that A == X, and we've got a noop move.  In
+	 that case don't do anything and let the code below delete INSN_A.  */
+      if (insn_b && else_bb)
+	{
+	  if (else_bb && insn_b == else_bb->end)
+	    else_bb->end = PREV_INSN (insn_b);
+	  reorder_insns (insn_b, insn_b, PREV_INSN (if_info.cond_earliest));
+	  insn_b = NULL_RTX;
+	  x = orig_x;
+	}
+      goto success;
+    }
+
+  if (noce_try_store_flag (&if_info))
+    goto success;
+  if (HAVE_conditional_move
+      && noce_try_cmove (&if_info))
+    goto success;
+  if (! HAVE_conditional_execution)
+    {
+      if (noce_try_store_flag_constants (&if_info))
+	goto success;
+      if (noce_try_store_flag_inc (&if_info))
+	goto success;
+      if (noce_try_store_flag_mask (&if_info))
+	goto success;
+      if (HAVE_conditional_move
+	  && noce_try_cmove_arith (&if_info))
+	goto success;
+    }
+
+  return FALSE;
+
+ success:
+  /* The original sets may now be killed.  */
+  if (insn_a == then_bb->end)
+    then_bb->end = PREV_INSN (insn_a);
+  flow_delete_insn (insn_a);
+
+  /* Several special cases here: First, we may have reused insn_b above,
+     in which case insn_b is now NULL.  Second, we want to delete insn_b
+     if it came from the ELSE block, because follows the now correct
+     write that appears in the TEST block.  However, if we got insn_b from
+     the TEST block, it may in fact be loading data needed for the comparison.
+     We'll let life_analysis remove the insn if it's really dead.  */
+  if (insn_b && else_bb)
+    {
+      if (insn_b == else_bb->end)
+	else_bb->end = PREV_INSN (insn_b);
+      flow_delete_insn (insn_b);
+    }
+
+  /* The new insns will have been inserted before cond_earliest.  We should
+     be able to remove cond_earliest through the jump with impunity.  */
+  insn_a = prev_nonnote_insn (if_info.cond_earliest);
+  flow_delete_insn_chain (if_info.cond_earliest, test_bb->end);
+  test_bb->end = insn_a;
+
+  /* If we used a temporary, fix it up now.  */
+  if (orig_x != x)
+    {
+      start_sequence ();
+      emit_move_insn (orig_x, x);
+      insn_b = gen_sequence ();
+      end_sequence ();
+
+      test_bb->end = emit_insn_after (insn_b, insn_a);
+    }
+
+  /* Merge the blocks!  */
+  merge_if_block (test_bb, then_bb, else_bb, join_bb);
+
+  return TRUE;
+}
+
+/* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
+   straight line code.  Return true if successful.  */
+
+static int
+process_if_block (test_bb, then_bb, else_bb, join_bb)
+     basic_block test_bb;	/* Basic block test is in */
+     basic_block then_bb;	/* Basic block for THEN block */
+     basic_block else_bb;	/* Basic block for ELSE block */
+     basic_block join_bb;	/* Basic block the join label is in */
+{
+  if (! reload_completed
+      && noce_process_if_block (test_bb, then_bb, else_bb, join_bb))
+    return TRUE;
+
+  if (HAVE_conditional_execution
+      && reload_completed
+      && cond_exec_process_if_block (test_bb, then_bb, else_bb, join_bb))
+    return TRUE;
+
+  return FALSE;
+}
+
+/* Merge the blocks and mark for local life update.  */
+
+static void
+merge_if_block (test_bb, then_bb, else_bb, join_bb)
+     basic_block test_bb;	/* Basic block test is in */
+     basic_block then_bb;	/* Basic block for THEN block */
+     basic_block else_bb;	/* Basic block for ELSE block */
+     basic_block join_bb;	/* Basic block the join label is in */
+{
+  basic_block combo_bb;
+
+  /* All block merging is done into the lower block numbers.  */
+
+  combo_bb = test_bb;
+
+  /* First merge TEST block into THEN block.  This is a no-brainer since
+     the THEN block did not have a code label to begin with.  */
+
+  if (combo_bb->global_live_at_end)
+    COPY_REG_SET (combo_bb->global_live_at_end, then_bb->global_live_at_end);
+  merge_blocks_nomove (combo_bb, then_bb);
+  num_removed_blocks++;
+
+  /* The ELSE block, if it existed, had a label.  That label count
+     will almost always be zero, but odd things can happen when labels
+     get their addresses taken.  */
+  if (else_bb)
+    {
+      if (LABEL_NUSES (else_bb->head) == 0
+	  && ! LABEL_PRESERVE_P (else_bb->head)
+	  && ! LABEL_NAME (else_bb->head))
+	{
+	  /* We can merge the ELSE.  */
+	  merge_blocks_nomove (combo_bb, else_bb);
+	  num_removed_blocks++;
+	}
+      else
+	{
+	  /* We cannot merge the ELSE.  */
+
+	  /* Properly rewire the edge out of the now combined
+	     TEST-THEN block to point here.  */
+	  remove_edge (combo_bb->succ);
+	  if (combo_bb->succ || else_bb->pred)
+	    abort ();
+	  make_edge (NULL, combo_bb, else_bb, EDGE_FALLTHRU);
+
+	  /* Remove the jump and cruft from the end of the TEST-THEN block.  */
+	  tidy_fallthru_edge (combo_bb->succ, combo_bb, else_bb);
+
+	  /* Make sure we update life info properly.  */
+	  SET_UPDATE_LIFE(combo_bb);
+	  if (else_bb->global_live_at_end)
+	    COPY_REG_SET (else_bb->global_live_at_start,
+			  else_bb->global_live_at_end);
+
+	  /* The ELSE is the new combo block.  */
+	  combo_bb = else_bb;
+	}
+    }
+
+  /* If there was no join block reported, that means it was not adjacent
+     to the others, and so we cannot merge them.  */
+
+  if (! join_bb)
+    {
+      /* The outgoing edge for the current COMBO block should already
+	 be correct.  Verify this.  */
+      if (combo_bb->succ == NULL_EDGE)
+	abort ();
+
+      /* There should sill be a branch at the end of the THEN or ELSE
+         blocks taking us to our final destination.  */
+      if (! simplejump_p (combo_bb->end)
+          && ! returnjump_p (combo_bb->end))
+	abort ();
+    }
+
+  /* The JOIN block had a label.  It may have had quite a number
+     of other predecessors too, but probably not.  See if we can
+     merge this with the others.  */
+  else if (LABEL_NUSES (join_bb->head) == 0
+      && ! LABEL_PRESERVE_P (join_bb->head)
+      && ! LABEL_NAME (join_bb->head))
+    {
+      /* We can merge the JOIN.  */
+      if (combo_bb->global_live_at_end)
+	COPY_REG_SET (combo_bb->global_live_at_end,
+		      join_bb->global_live_at_end);
+      merge_blocks_nomove (combo_bb, join_bb);
+      num_removed_blocks++;
+    }
+  else
+    {
+      /* We cannot merge the JOIN.  */
+
+      /* The outgoing edge for the current COMBO block should already
+	 be correct.  Verify this.  */
+      if (combo_bb->succ->succ_next != NULL_EDGE
+	  || combo_bb->succ->dest != join_bb)
+	abort ();
+
+      /* Remove the jump and cruft from the end of the COMBO block.  */
+      tidy_fallthru_edge (combo_bb->succ, combo_bb, join_bb);
+    }
+
+  /* Make sure we update life info properly.  */
+  SET_UPDATE_LIFE (combo_bb);
+
+  num_updated_if_blocks++;
+}
+
+/* Find a block ending in a simple IF condition.  Return TRUE if
+   we were able to transform it in some way.  */
+
+static int
+find_if_header (test_bb)
+     basic_block test_bb;
+{
+  edge then_edge;
+  edge else_edge;
+
+  /* The kind of block we're looking for has exactly two successors.  */
+  if ((then_edge = test_bb->succ) == NULL_EDGE
+      || (else_edge = then_edge->succ_next) == NULL_EDGE
+      || else_edge->succ_next != NULL_EDGE)
+    return FALSE;
+
+  /* Neither edge should be abnormal.  */
+  if ((then_edge->flags & EDGE_COMPLEX)
+      || (else_edge->flags & EDGE_COMPLEX))
+    return FALSE;
+
+  /* The THEN edge is canonically the one that falls through.  */
+  if (then_edge->flags & EDGE_FALLTHRU)
+    ;
+  else if (else_edge->flags & EDGE_FALLTHRU)
+    {
+      edge e = else_edge;
+      else_edge = then_edge;
+      then_edge = e;
+    }
+  else
+    /* Otherwise this must be a multiway branch of some sort.  */
+    return FALSE;
+
+  if (find_if_block (test_bb, then_edge, else_edge))
+    goto success;
+  if (post_dominators
+      && (! HAVE_conditional_execution || reload_completed))
+    {
+      if (find_if_case_1 (test_bb, then_edge, else_edge))
+	goto success;
+      if (find_if_case_2 (test_bb, then_edge, else_edge))
+	goto success;
+    }
+
+  return FALSE;
+
+ success:
+  if (rtl_dump_file)
+    fprintf (rtl_dump_file, "Conversion succeeded.\n");
+  return TRUE;
+}
+
+/* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
+   block.  If so, we'll try to convert the insns to not require the branch.
+   Return TRUE if we were successful at converting the the block.  */
+
+static int
+find_if_block (test_bb, then_edge, else_edge)
+      basic_block test_bb;
+      edge then_edge, else_edge;
+{
+  basic_block then_bb = then_edge->dest;
+  basic_block else_bb = else_edge->dest;
+  basic_block join_bb = NULL_BLOCK;
+  edge then_succ = then_bb->succ;
+  edge else_succ = else_bb->succ;
+  int next_index;
+
+  /* The THEN block of an IF-THEN combo must have exactly one predecessor.  */
+  if (then_bb->pred->pred_next != NULL_EDGE)
+    return FALSE;
+
+  /* The THEN block of an IF-THEN combo must have exactly one successor.  */
+  if (then_succ == NULL_EDGE
+      || then_succ->succ_next != NULL_EDGE
+      || (then_succ->flags & EDGE_COMPLEX))
+    return FALSE;
+
+  /* The THEN block may not start with a label, as might happen with an
+     unused user label that has had its address taken.  */
+  if (GET_CODE (then_bb->head) == CODE_LABEL)
+    return FALSE;
+
+  /* If the THEN block's successor is the other edge out of the TEST block,
+     then we have an IF-THEN combo without an ELSE.  */
+  if (then_succ->dest == else_bb)
+    {
+      join_bb = else_bb;
+      else_bb = NULL_BLOCK;
+    }
+
+  /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
+     has exactly one predecessor and one successor, and the outgoing edge
+     is not complex, then we have an IF-THEN-ELSE combo.  */
+  else if (else_succ != NULL_EDGE
+	   && then_succ->dest == else_succ->dest
+	   && else_bb->pred->pred_next == NULL_EDGE
+	   && else_succ->succ_next == NULL_EDGE
+	   && ! (else_succ->flags & EDGE_COMPLEX))
+    join_bb = else_succ->dest;
+
+  /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination.  */
+  else
+    return FALSE;	   
+
+  num_possible_if_blocks++;
+
+  if (rtl_dump_file)
+    {
+      if (else_bb)
+	fprintf (rtl_dump_file,
+		 "\nIF-THEN-ELSE block found, start %d, then %d, else %d, join %d\n",
+		 test_bb->index, then_bb->index, else_bb->index,
+		 join_bb->index);
+      else
+	fprintf (rtl_dump_file,
+		 "\nIF-THEN block found, start %d, then %d, join %d\n",
+		 test_bb->index, then_bb->index, join_bb->index);
+    }
+
+  /* Make sure IF, THEN, and ELSE, blocks are adjacent.  Actually, we
+     get the first condition for free, since we've already asserted that
+     there's a fallthru edge from IF to THEN.  */
+  /* ??? As an enhancement, move the ELSE block.  Have to deal with EH and
+     BLOCK notes, if by no other means than aborting the merge if they
+     exist.  Sticky enough I don't want to think about it now.  */
+  next_index = then_bb->index;
+  if (else_bb && ++next_index != else_bb->index)
+    return FALSE;
+  if (++next_index != join_bb->index)
+    {
+      if (else_bb)
+	join_bb = NULL;
+      else
+	return FALSE;
+    }
+
+  /* Do the real work.  */
+  return process_if_block (test_bb, then_bb, else_bb, join_bb);
+}
+
+/* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
+   transformable, but not necessarily the other.  There need be no
+   JOIN block.
+
+   Return TRUE if we were successful at converting the the block.
+
+   Cases we'd like to look at:
+
+   (1)
+	if (test) goto over; // x not live
+	x = a;
+	goto label;
+	over:
+
+   becomes
+
+	x = a;
+	if (! test) goto label;
+
+   (2)
+	if (test) goto E; // x not live
+	x = big();
+	goto L;
+	E:
+	x = b;
+	goto M;
+
+   becomes
+
+	x = b;
+	if (test) goto M;
+	x = big();
+	goto L;
+
+   (3) // This one's really only interesting for targets that can do
+       // multiway branching, e.g. IA-64 BBB bundles.  For other targets
+       // it results in multiple branches on a cache line, which often
+       // does not sit well with predictors.
+
+	if (test1) goto E; // predicted not taken
+	x = a;
+	if (test2) goto F;
+	...
+	E:
+	x = b;
+	J:
+
+   becomes
+
+	x = a;
+	if (test1) goto E;
+	if (test2) goto F;
+
+   Notes:
+
+   (A) Don't do (2) if the branch is predicted against the block we're
+   eliminating.  Do it anyway if we can eliminate a branch; this requires
+   that the sole successor of the eliminated block postdominate the other
+   side of the if.
+
+   (B) With CE, on (3) we can steal from both sides of the if, creating
+
+	if (test1) x = a;
+	if (!test1) x = b;
+	if (test1) goto J;
+	if (test2) goto F;
+	...
+	J:
+
+   Again, this is most useful if J postdominates.
+
+   (C) CE substitutes for helpful life information.
+
+   (D) These heuristics need a lot of work.  */
+
+/* Tests for case 1 above.  */
+
+static int
+find_if_case_1 (test_bb, then_edge, else_edge)
+      basic_block test_bb;
+      edge then_edge, else_edge;
+{
+  basic_block then_bb = then_edge->dest;
+  basic_block else_bb = else_edge->dest;
+  edge then_succ = then_bb->succ;
+  rtx new_lab;
+
+  /* THEN has one successor.  */
+  if (!then_succ || then_succ->succ_next != NULL)
+    return FALSE;
+
+  /* THEN does not fall through, but is not strange either.  */
+  if (then_succ->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))
+    return FALSE;
+
+  /* THEN has one predecessor.  */
+  if (then_bb->pred->pred_next != NULL)
+    return FALSE;
+
+  /* THEN has no label.  */
+  if (GET_CODE (then_bb->head) == CODE_LABEL)
+    return FALSE;
+
+  /* ELSE follows THEN.  (??? could be moved)  */
+  if (else_bb->index != then_bb->index + 1)
+    return FALSE;
+
+  num_possible_if_blocks++;
+  if (rtl_dump_file)
+    fprintf (rtl_dump_file,
+	     "\nIF-CASE-1 found, start %d, then %d\n",
+	     test_bb->index, then_bb->index);
+
+  /* THEN is small.  */
+  if (count_bb_insns (then_bb) > BRANCH_COST)
+    return FALSE;
+
+  /* Find the label for THEN's destination.  */
+  if (then_succ->dest == EXIT_BLOCK_PTR)
+    new_lab = NULL_RTX;
+  else
+    {
+      new_lab = JUMP_LABEL (then_bb->end);
+      if (! new_lab)
+	abort ();
+    }
+
+  /* Registers set are dead, or are predicable.  */
+  if (! dead_or_predicable (test_bb, then_bb, else_bb, new_lab, 1))
+    return FALSE;
+
+  /* Conversion went ok, including moving the insns and fixing up the
+     jump.  Adjust the CFG to match.  */
+
+  SET_UPDATE_LIFE (test_bb);
+  bitmap_operation (test_bb->global_live_at_end,
+		    else_bb->global_live_at_start,
+		    then_bb->global_live_at_end, BITMAP_IOR);
+  
+  make_edge (NULL, test_bb, then_succ->dest, 0);
+  flow_delete_block (then_bb);
+  tidy_fallthru_edge (else_edge, test_bb, else_bb);
+
+  num_removed_blocks++;
+  num_updated_if_blocks++;
+
+  return TRUE;
+}
+
+/* Test for case 2 above.  */
+
+static int
+find_if_case_2 (test_bb, then_edge, else_edge)
+      basic_block test_bb;
+      edge then_edge, else_edge;
+{
+  basic_block then_bb = then_edge->dest;
+  basic_block else_bb = else_edge->dest;
+  edge else_succ = else_bb->succ;
+  rtx new_lab, note;
+
+  /* ELSE has one successor.  */
+  if (!else_succ || else_succ->succ_next != NULL)
+    return FALSE;
+
+  /* ELSE outgoing edge is not complex.  */
+  if (else_succ->flags & EDGE_COMPLEX)
+    return FALSE;
+
+  /* ELSE has one predecessor.  */
+  if (else_bb->pred->pred_next != NULL)
+    return FALSE;
+
+  /* ELSE has a label we can delete.  */
+  if (LABEL_NUSES (else_bb->head) > 1
+      || LABEL_PRESERVE_P (else_bb->head)
+      || LABEL_NAME (else_bb->head))
+    return FALSE;
+
+  /* ELSE is predicted or SUCC(ELSE) postdominates THEN.  */
+  note = find_reg_note (test_bb->end, REG_BR_PROB, NULL_RTX);
+  if (note && INTVAL (XEXP (note, 0)) >= REG_BR_PROB_BASE / 2)
+    ;
+  else if (else_succ->dest->index < 0
+	   || (then_bb->index >= 0
+	       && TEST_BIT (post_dominators[ORIG_INDEX (then_bb)], 
+			    ORIG_INDEX (else_succ->dest))))
+    ;
+  else
+    return FALSE;
+
+  num_possible_if_blocks++;
+  if (rtl_dump_file)
+    fprintf (rtl_dump_file,
+	     "\nIF-CASE-2 found, start %d, else %d\n",
+	     test_bb->index, else_bb->index);
+
+  /* ELSE is small.  */
+  if (count_bb_insns (then_bb) > BRANCH_COST)
+    return FALSE;
+
+  /* Find the label for ELSE's destination.  */
+  if (else_succ->dest == EXIT_BLOCK_PTR)
+    new_lab = NULL_RTX;
+  else
+    {
+      if (else_succ->flags & EDGE_FALLTHRU)
+	{
+	  new_lab = else_succ->dest->head;
+	  if (GET_CODE (new_lab) != CODE_LABEL)
+	    abort ();
+	}
+      else
+	{
+	  new_lab = JUMP_LABEL (else_bb->end);
+	  if (! new_lab)
+	    abort ();
+	}
+    }
+
+  /* Registers set are dead, or are predicable.  */
+  if (! dead_or_predicable (test_bb, else_bb, then_bb, new_lab, 0))
+    return FALSE;
+
+  /* Conversion went ok, including moving the insns and fixing up the
+     jump.  Adjust the CFG to match.  */
+
+  SET_UPDATE_LIFE (test_bb);
+  bitmap_operation (test_bb->global_live_at_end,
+		    then_bb->global_live_at_start,
+		    else_bb->global_live_at_end, BITMAP_IOR);
+  
+  remove_edge (else_edge);
+  make_edge (NULL, test_bb, else_succ->dest, 0);
+  flow_delete_block (else_bb);
+
+  num_removed_blocks++;
+  num_updated_if_blocks++;
+
+  /* ??? We may now fallthru from one of THEN's successors into a join
+     block.  Rerun cleanup_cfg?  Examine things manually?  Wait?  */
+
+  return TRUE;
+}
+
+/* A subroutine of dead_or_predicable called through for_each_rtx.
+   Return 1 if a memory is found.  */
+
+static int
+find_memory (px, data)
+     rtx *px;
+     void *data ATTRIBUTE_UNUSED;
+{
+  return GET_CODE (*px) == MEM;
+}
+
+/* Used by the code above to perform the actual rtl transformations.
+   Return TRUE if successful.
+
+   TEST_BB is the block containing the conditional branch.  MERGE_BB
+   is the block containing the code to manipulate.  NEW_DEST is the
+   label TEST_BB should be branching to after the conversion.
+   REVERSEP is true if the sense of the branch should be reversed.  */
+
+static int
+dead_or_predicable (test_bb, merge_bb, other_bb, new_dest, reversep)
+     basic_block test_bb, merge_bb, other_bb;
+     rtx new_dest;
+     int reversep;
+{
+  rtx head, end, jump, earliest, old_dest;
+
+  jump = test_bb->end;
+
+  /* Find the extent of the real code in the merge block.  */
+  head = merge_bb->head;
+  end = merge_bb->end;
+
+  if (GET_CODE (head) == CODE_LABEL)
+    head = NEXT_INSN (head);
+  if (GET_CODE (head) == NOTE)
+    {
+      if (head == end)
+	{
+	  head = end = NULL_RTX;
+	  goto no_body;
+	}
+      head = NEXT_INSN (head);
+    }
+
+  if (GET_CODE (end) == JUMP_INSN)
+    {
+      if (head == end)
+	{
+	  head = end = NULL_RTX;
+	  goto no_body;
+	}
+      end = PREV_INSN (end);
+    }
+
+  if (HAVE_conditional_execution)
+    {
+      /* In the conditional execution case, we have things easy.  We know
+	 the condition is reversable.  We don't have to check life info,
+	 becase we're going to conditionally execute the code anyway.
+	 All that's left is making sure the insns involved can actually
+	 be predicated.  */
+
+      rtx cond;
+
+      cond = cond_exec_get_condition (jump);
+      if (reversep)
+	cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
+			       GET_MODE (cond), XEXP (cond, 0),
+			       XEXP (cond, 1));
+
+      if (! cond_exec_process_insns (head, end, cond, 0))
+	goto cancel;
+
+      earliest = jump;
+    }
+  else
+    {
+      /* In the non-conditional execution case, we have to verify that there
+	 are no trapping operations, no calls, no references to memory, and
+	 that any registers modified are dead at the branch site.  */
+
+      rtx insn, cond, prev;
+      regset_head merge_set_head, tmp_head, test_live_head, test_set_head;
+      regset merge_set, tmp, test_live, test_set;
+      struct propagate_block_info *pbi;
+      int i, fail = 0;
+
+      /* Check for no calls or trapping operations.  */
+      for (insn = head; ; insn = NEXT_INSN (insn))
+	{
+	  if (GET_CODE (insn) == CALL_INSN)
+	    return FALSE;
+	  if (INSN_P (insn))
+	    {
+	      if (may_trap_p (PATTERN (insn)))
+		return FALSE;
+
+	      /* ??? Even non-trapping memories such as stack frame
+		 references must be avoided.  For stores, we collect
+		 no lifetime info; for reads, we'd have to assert
+		 true_dependance false against every store in the
+		 TEST range.  */
+	      if (for_each_rtx (&PATTERN (insn), find_memory, NULL))
+		return FALSE;
+	    }
+	  if (insn == end)
+	    break;
+	}
+
+      if (! condjump_p (jump))
+	return FALSE;
+
+      /* Find the extent of the conditional.  */
+      cond = noce_get_condition (jump, &earliest);
+      if (! cond)
+	return FALSE;
+
+      /* Collect:
+	   MERGE_SET = set of registers set in MERGE_BB
+	   TEST_LIVE = set of registers live at EARLIEST
+	   TEST_SET  = set of registers set between EARLIEST and the
+		       end of the block.  */
+
+      tmp = INITIALIZE_REG_SET (tmp_head);
+      merge_set = INITIALIZE_REG_SET (merge_set_head);
+      test_live = INITIALIZE_REG_SET (test_live_head);
+      test_set = INITIALIZE_REG_SET (test_set_head);
+
+      /* ??? bb->local_set is only valid during calculate_global_regs_live,
+	 so we must recompute usage for MERGE_BB.  Not so bad, I suppose, 
+         since we've already asserted that MERGE_BB is small.  */
+      propagate_block (merge_bb, tmp, merge_set, 0);
+
+      /* For small register class machines, don't lengthen lifetimes of
+	 hard registers before reload.  */
+      if (SMALL_REGISTER_CLASSES && ! reload_completed)
+	{
+          EXECUTE_IF_SET_IN_BITMAP
+	    (merge_set, 0, i,
+	     {
+	       if (i < FIRST_PSEUDO_REGISTER
+		   && ! fixed_regs[i]
+		   && ! global_regs[i])
+		fail = 1;
+	     });
+	}
+
+      /* For TEST, we're interested in a range of insns, not a whole block.
+	 Moreover, we're interested in the insns live from OTHER_BB.  */
+
+      COPY_REG_SET (test_live, other_bb->global_live_at_start);
+      pbi = init_propagate_block_info (test_bb, test_live, test_set, 0);
+
+      for (insn = jump; ; insn = prev)
+	{
+	  prev = propagate_one_insn (pbi, insn);
+	  if (insn == earliest)
+	    break;
+	}
+
+      free_propagate_block_info (pbi);
+
+      /* We can perform the transformation if
+	   MERGE_SET & (TEST_SET | TEST_LIVE)
+	 and
+	   TEST_SET & merge_bb->global_live_at_start
+	 are empty.  */
+
+      bitmap_operation (tmp, test_set, test_live, BITMAP_IOR);
+      bitmap_operation (tmp, tmp, merge_set, BITMAP_AND);
+      EXECUTE_IF_SET_IN_BITMAP(tmp, 0, i, fail = 1);
+
+      bitmap_operation (tmp, test_set, merge_bb->global_live_at_start,
+			BITMAP_AND);
+      EXECUTE_IF_SET_IN_BITMAP(tmp, 0, i, fail = 1);
+
+      FREE_REG_SET (tmp);
+      FREE_REG_SET (merge_set);
+      FREE_REG_SET (test_live);
+      FREE_REG_SET (test_set);
+
+      if (fail)
+	return FALSE;
+    }
+
+ no_body:
+  /* We don't want to use normal invert_jump or redirect_jump because
+     we don't want to delete_insn called.  Also, we want to do our own
+     change group management.  */
+
+  old_dest = JUMP_LABEL (jump);
+  if (reversep
+      ? ! invert_jump_1 (jump, new_dest)
+      : ! redirect_jump_1 (jump, new_dest))
+    goto cancel;
+
+  if (! apply_change_group ())
+    return FALSE;
+
+  if (old_dest)
+    LABEL_NUSES (old_dest) -= 1;
+  if (new_dest)
+    LABEL_NUSES (new_dest) += 1;
+  JUMP_LABEL (jump) = new_dest;
+
+  if (reversep)
+    {
+      rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
+      if (note)
+	XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
+    }
+
+  /* Move the insns out of MERGE_BB to before the branch.  */
+  if (end == merge_bb->end)
+    merge_bb->end = merge_bb->head;
+  if (head != NULL)
+    {
+      head = squeeze_notes (head, end);
+      reorder_insns (head, end, PREV_INSN (earliest));
+    }
+  return TRUE;
+
+ cancel:
+  cancel_changes (0);
+  return FALSE;
+}
+
+/* Main entry point for all if-conversion.  */
+
+void
+if_convert (life_data_ok)
+     int life_data_ok;
+{
+  int block_num;
+
+  num_possible_if_blocks = 0;
+  num_updated_if_blocks = 0;
+  num_removed_blocks = 0;
+
+  /* Free up basic_block_for_insn so that we don't have to keep it 
+     up to date, either here or in merge_blocks_nomove.  */
+  free_basic_block_vars (1);
+
+  /* Compute postdominators if we think we'll use them.  */
+  post_dominators = NULL;
+  if (HAVE_conditional_execution || life_data_ok)
+    {
+      post_dominators = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
+      compute_flow_dominators (NULL, post_dominators);
+    }
+
+  /* Record initial block numbers.  */
+  for (block_num = 0; block_num < n_basic_blocks; block_num++)
+    SET_ORIG_INDEX (BASIC_BLOCK (block_num), block_num);
+
+  /* Go through each of the basic blocks looking for things to convert.  */
+  for (block_num = 0; block_num < n_basic_blocks; )
+    {
+      basic_block bb = BASIC_BLOCK (block_num);
+      if (find_if_header (bb))
+	block_num = bb->index;
+      else 
+	block_num++;
+    }
+
+  sbitmap_vector_free (post_dominators);
+
+  if (rtl_dump_file)
+    fflush (rtl_dump_file);
+
+  /* Rebuild basic_block_for_insn for update_life_info and for gcse.  */
+  compute_bb_for_insn (get_max_uid ());
+
+  /* Rebuild life info for basic blocks that require it.  */
+  if (num_removed_blocks && life_data_ok)
+    {
+      sbitmap update_life_blocks = sbitmap_alloc (n_basic_blocks);
+      sbitmap_zero (update_life_blocks);
+
+      /* If we allocated new pseudos, we must resize the array for sched1.  */
+      if (max_regno < max_reg_num ())
+	{
+	  max_regno = max_reg_num ();
+	  allocate_reg_info (max_regno, FALSE, FALSE);
+	}
+
+      for (block_num = 0; block_num < n_basic_blocks; block_num++)
+	if (UPDATE_LIFE (BASIC_BLOCK (block_num)))
+	  SET_BIT (update_life_blocks, block_num);
+
+      count_or_remove_death_notes (update_life_blocks, 1);
+      update_life_info (update_life_blocks, UPDATE_LIFE_LOCAL,
+			PROP_DEATH_NOTES);
+
+      sbitmap_free (update_life_blocks);
+    }
+
+  /* Write the final stats.  */
+  if (rtl_dump_file && num_possible_if_blocks > 0)
+    {
+      fprintf (rtl_dump_file,
+	       "\n%d possible IF blocks searched.\n",
+	       num_possible_if_blocks);
+      fprintf (rtl_dump_file,
+	       "%d IF blocks converted.\n",
+	       num_updated_if_blocks);
+      fprintf (rtl_dump_file,
+	       "%d basic blocks deleted.\n\n\n",
+	       num_removed_blocks);
+    }
+
+  verify_flow_info ();
+}

gcc/jump.c

@@ -128,9 +128,6 @@ static int delete_labelref_insn		PARAMS ((rtx, rtx, int));
 static void mark_modified_reg		PARAMS ((rtx, rtx, void *));
 static void redirect_tablejump		PARAMS ((rtx, rtx));
 static void jump_optimize_1		PARAMS ((rtx, int, int, int, int, int));
-#if ! defined(HAVE_cc0) && ! defined(HAVE_conditional_arithmetic)
-static rtx find_insert_position         PARAMS ((rtx, rtx));
-#endif
 static int returnjump_p_1	        PARAMS ((rtx *, void *));
 static void delete_prior_computation    PARAMS ((rtx, rtx));
 
@@ -300,9 +297,10 @@ jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
       for (insn = f; insn; insn = next)
 	{
 	  rtx reallabelprev;
-	  rtx temp, temp1, temp2 = NULL_RTX, temp3, temp4, temp5, temp6;
+	  rtx temp, temp1, temp2 = NULL_RTX;
+	  rtx temp4 ATTRIBUTE_UNUSED;
 	  rtx nlabel;
-	  int this_is_simplejump, this_is_condjump, reversep = 0;
+	  int this_is_simplejump, this_is_condjump;
 	  int this_is_condjump_in_parallel;
 
 	  next = NEXT_INSN (insn);
@@ -514,1437 +512,18 @@ jump_optimize_1 (f, cross_jump, noop_moves, after_regscan,
 	      next = NEXT_INSN (insn);
 	    }
 
-	  /* Simplify   if (...) x = a; else x = b; by converting it
-	     to         x = b; if (...) x = a;
-	     if B is sufficiently simple, the test doesn't involve X,
-	     and nothing in the test modifies B or X.
-
-	     If we have small register classes, we also can't do this if X
-	     is a hard register.
-
-	     If the "x = b;" insn has any REG_NOTES, we don't do this because
-	     of the possibility that we are running after CSE and there is a
-	     REG_EQUAL note that is only valid if the branch has already been
-	     taken.  If we move the insn with the REG_EQUAL note, we may
-	     fold the comparison to always be false in a later CSE pass.
-	     (We could also delete the REG_NOTES when moving the insn, but it
-	     seems simpler to not move it.)  An exception is that we can move
-	     the insn if the only note is a REG_EQUAL or REG_EQUIV whose
-	     value is the same as "b".
-
-	     INSN is the branch over the `else' part. 
-
-	     We set:
-
-	     TEMP to the jump insn preceding "x = a;"
-	     TEMP1 to X
-	     TEMP2 to the insn that sets "x = b;"
-	     TEMP3 to the insn that sets "x = a;"
-	     TEMP4 to the set of "x = b";  */
-
-	  if (this_is_simplejump
-	      && (temp3 = prev_active_insn (insn)) != 0
-	      && GET_CODE (temp3) == INSN
-	      && (temp4 = single_set (temp3)) != 0
-	      && GET_CODE (temp1 = SET_DEST (temp4)) == REG
-	      && (! SMALL_REGISTER_CLASSES
-		  || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
-	      && (temp2 = next_active_insn (insn)) != 0
-	      && GET_CODE (temp2) == INSN
-	      && (temp4 = single_set (temp2)) != 0
-	      && rtx_equal_p (SET_DEST (temp4), temp1)
-	      && ! side_effects_p (SET_SRC (temp4))
-	      && ! may_trap_p (SET_SRC (temp4))
-	      && (REG_NOTES (temp2) == 0
-		  || ((REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUAL
-		       || REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUIV)
-		      && XEXP (REG_NOTES (temp2), 1) == 0
-		      && rtx_equal_p (XEXP (REG_NOTES (temp2), 0),
-				      SET_SRC (temp4))))
-	      && (temp = prev_active_insn (temp3)) != 0
-	      && condjump_p (temp) && ! simplejump_p (temp)
-	      /* TEMP must skip over the "x = a;" insn */
-	      && prev_real_insn (JUMP_LABEL (temp)) == insn
-	      && no_labels_between_p (insn, JUMP_LABEL (temp))
-	      /* There must be no other entries to the "x = b;" insn.  */
-	      && no_labels_between_p (JUMP_LABEL (temp), temp2)
-	      /* INSN must either branch to the insn after TEMP2 or the insn
-		 after TEMP2 must branch to the same place as INSN.  */
-	      && (reallabelprev == temp2
-		  || ((temp5 = next_active_insn (temp2)) != 0
-		      && simplejump_p (temp5)
-		      && JUMP_LABEL (temp5) == JUMP_LABEL (insn))))
-	    {
-	      /* The test expression, X, may be a complicated test with
-		 multiple branches.  See if we can find all the uses of
-		 the label that TEMP branches to without hitting a CALL_INSN
-		 or a jump to somewhere else.  */
-	      rtx target = JUMP_LABEL (temp);
-	      int nuses = LABEL_NUSES (target);
-	      rtx p;
-#ifdef HAVE_cc0
-	      rtx q;
-#endif
-
-	      /* Set P to the first jump insn that goes around "x = a;".  */
-	      for (p = temp; nuses && p; p = prev_nonnote_insn (p))
-		{
-		  if (GET_CODE (p) == JUMP_INSN)
-		    {
-		      if (condjump_p (p) && ! simplejump_p (p)
-			  && JUMP_LABEL (p) == target)
-			{
-			  nuses--;
-			  if (nuses == 0)
-			    break;
-			}
-		      else
-			break;
-		    }
-		  else if (GET_CODE (p) == CALL_INSN)
-		    break;
-		}
-
-#ifdef HAVE_cc0
-	      /* We cannot insert anything between a set of cc and its use
-		 so if P uses cc0, we must back up to the previous insn.  */
-	      q = prev_nonnote_insn (p);
-	      if (q && GET_RTX_CLASS (GET_CODE (q)) == 'i'
-		  && sets_cc0_p (PATTERN (q)))
-		p = q;
-#endif
-
-	      if (p)
-		p = PREV_INSN (p);
-
-	      /* If we found all the uses and there was no data conflict, we
-		 can move the assignment unless we can branch into the middle
-		 from somewhere.  */
-	      if (nuses == 0 && p
-		  && no_labels_between_p (p, insn)
-		  && ! reg_referenced_between_p (temp1, p, NEXT_INSN (temp3))
-		  && ! reg_set_between_p (temp1, p, temp3)
-		  && (GET_CODE (SET_SRC (temp4)) == CONST_INT
-		      || ! modified_between_p (SET_SRC (temp4), p, temp2))
-		  /* Verify that registers used by the jump are not clobbered
-		     by the instruction being moved.  */
-		  && ! regs_set_between_p (PATTERN (temp),
-					   PREV_INSN (temp2),
-					   NEXT_INSN (temp2)))
-		{
-		  emit_insn_after_with_line_notes (PATTERN (temp2), p, temp2);
-		  delete_insn (temp2);
-
-		  /* Set NEXT to an insn that we know won't go away.  */
-		  next = next_active_insn (insn);
-
-		  /* Delete the jump around the set.  Note that we must do
-		     this before we redirect the test jumps so that it won't
-		     delete the code immediately following the assignment
-		     we moved (which might be a jump).  */
-
-		  delete_insn (insn);
-
-		  /* We either have two consecutive labels or a jump to
-		     a jump, so adjust all the JUMP_INSNs to branch to where
-		     INSN branches to.  */
-		  for (p = NEXT_INSN (p); p != next; p = NEXT_INSN (p))
-		    if (GET_CODE (p) == JUMP_INSN)
-		      redirect_jump (p, target);
-
-		  changed = 1;
-		  next = NEXT_INSN (insn);
-		  continue;
-		}
-	    }
-
-	  /* Simplify   if (...) { x = a; goto l; } x = b; by converting it
-	     to         x = a; if (...) goto l; x = b;
-	     if A is sufficiently simple, the test doesn't involve X,
-	     and nothing in the test modifies A or X.
-
-	     If we have small register classes, we also can't do this if X
-	     is a hard register.
-
-	     If the "x = a;" insn has any REG_NOTES, we don't do this because
-	     of the possibility that we are running after CSE and there is a
-	     REG_EQUAL note that is only valid if the branch has already been
-	     taken.  If we move the insn with the REG_EQUAL note, we may
-	     fold the comparison to always be false in a later CSE pass.
-	     (We could also delete the REG_NOTES when moving the insn, but it
-	     seems simpler to not move it.)  An exception is that we can move
-	     the insn if the only note is a REG_EQUAL or REG_EQUIV whose
-	     value is the same as "a".
-
-	     INSN is the goto.
-
-	     We set:
-
-	     TEMP to the jump insn preceding "x = a;"
-	     TEMP1 to X
-	     TEMP2 to the insn that sets "x = b;"
-	     TEMP3 to the insn that sets "x = a;"
-	     TEMP4 to the set of "x = a";  */
-
-	  if (this_is_simplejump
-	      && (temp2 = next_active_insn (insn)) != 0
-	      && GET_CODE (temp2) == INSN
-	      && (temp4 = single_set (temp2)) != 0
-	      && GET_CODE (temp1 = SET_DEST (temp4)) == REG
-	      && (! SMALL_REGISTER_CLASSES
-		  || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
-	      && (temp3 = prev_active_insn (insn)) != 0
-	      && GET_CODE (temp3) == INSN
-	      && (temp4 = single_set (temp3)) != 0
-	      && rtx_equal_p (SET_DEST (temp4), temp1)
-	      && ! side_effects_p (SET_SRC (temp4))
-	      && ! may_trap_p (SET_SRC (temp4))
-	      && (REG_NOTES (temp3) == 0
-		  || ((REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUAL
-		       || REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUIV)
-		      && XEXP (REG_NOTES (temp3), 1) == 0
-		      && rtx_equal_p (XEXP (REG_NOTES (temp3), 0),
-				      SET_SRC (temp4))))
-	      && (temp = prev_active_insn (temp3)) != 0
-	      && condjump_p (temp) && ! simplejump_p (temp)
-	      /* TEMP must skip over the "x = a;" insn */
-	      && prev_real_insn (JUMP_LABEL (temp)) == insn
-	      && no_labels_between_p (temp, insn))
-	    {
-	      rtx prev_label = JUMP_LABEL (temp);
-	      rtx insert_after = prev_nonnote_insn (temp);
-
-#ifdef HAVE_cc0
-	      /* We cannot insert anything between a set of cc and its use.  */
-	      if (insert_after && GET_RTX_CLASS (GET_CODE (insert_after)) == 'i'
-		  && sets_cc0_p (PATTERN (insert_after)))
-		insert_after = prev_nonnote_insn (insert_after);
-#endif
-	      ++LABEL_NUSES (prev_label);
-
-	      if (insert_after
-		  && no_labels_between_p (insert_after, temp)
-		  && ! reg_referenced_between_p (temp1, insert_after, temp3)
-		  && ! reg_referenced_between_p (temp1, temp3,
-						 NEXT_INSN (temp2))
-		  && ! reg_set_between_p (temp1, insert_after, temp)
-		  && ! modified_between_p (SET_SRC (temp4), insert_after, temp)
-		  /* Verify that registers used by the jump are not clobbered
-		     by the instruction being moved.  */
-		  && ! regs_set_between_p (PATTERN (temp),
-					   PREV_INSN (temp3),
-					   NEXT_INSN (temp3))
-		  && invert_jump (temp, JUMP_LABEL (insn)))
-		{
-		  emit_insn_after_with_line_notes (PATTERN (temp3),
-						   insert_after, temp3);
-		  delete_insn (temp3);
-		  delete_insn (insn);
-		  /* Set NEXT to an insn that we know won't go away.  */
-		  next = temp2;
-		  changed = 1;
-		}
-	      if (prev_label && --LABEL_NUSES (prev_label) == 0)
-		delete_insn (prev_label);
-	      if (changed)
-		continue;
-	    }
-
-#if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
-
-	  /* If we have if (...) x = exp;  and branches are expensive,
-	     EXP is a single insn, does not have any side effects, cannot
-	     trap, and is not too costly, convert this to
-	     t = exp; if (...) x = t;
-
-	     Don't do this when we have CC0 because it is unlikely to help
-	     and we'd need to worry about where to place the new insn and
-	     the potential for conflicts.  We also can't do this when we have
-	     notes on the insn for the same reason as above.
-
-	     If we have conditional arithmetic, this will make this
-	     harder to optimize later and isn't needed, so don't do it
-	     in that case either.
-
-	     We set:
-
-	     TEMP to the "x = exp;" insn.
-	     TEMP1 to the single set in the "x = exp;" insn.
-	     TEMP2 to "x".  */
-
-	  if (! reload_completed
-	      && this_is_condjump && ! this_is_simplejump
-	      && BRANCH_COST >= 3
-	      && (temp = next_nonnote_insn (insn)) != 0
-	      && GET_CODE (temp) == INSN
-	      && REG_NOTES (temp) == 0
-	      && (reallabelprev == temp
-		  || ((temp2 = next_active_insn (temp)) != 0
-		      && simplejump_p (temp2)
-		      && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
-	      && (temp1 = single_set (temp)) != 0
-	      && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
-	      && (! SMALL_REGISTER_CLASSES
-		  || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
-	      && GET_CODE (SET_SRC (temp1)) != REG
-	      && GET_CODE (SET_SRC (temp1)) != SUBREG
-	      && GET_CODE (SET_SRC (temp1)) != CONST_INT
-	      && ! side_effects_p (SET_SRC (temp1))
-	      && ! may_trap_p (SET_SRC (temp1))
-	      && rtx_cost (SET_SRC (temp1), SET) < 10)
-	    {
-	      rtx new = gen_reg_rtx (GET_MODE (temp2));
-
-	      if ((temp3 = find_insert_position (insn, temp))
-		  && validate_change (temp, &SET_DEST (temp1), new, 0))
-		{
-		  next = emit_insn_after (gen_move_insn (temp2, new), insn);
-		  emit_insn_after_with_line_notes (PATTERN (temp), 
-						   PREV_INSN (temp3), temp);
-		  delete_insn (temp);
-		  reallabelprev = prev_active_insn (JUMP_LABEL (insn));
-
-		  if (after_regscan)
-		    {
-		      reg_scan_update (temp3, NEXT_INSN (next), old_max_reg);
-		      old_max_reg = max_reg_num ();
-		    }
-		}
-	    }
-
-	  /* Similarly, if it takes two insns to compute EXP but they
-	     have the same destination.  Here TEMP3 will be the second
-	     insn and TEMP4 the SET from that insn.  */
-
-	  if (! reload_completed
-	      && this_is_condjump && ! this_is_simplejump
-	      && BRANCH_COST >= 4
-	      && (temp = next_nonnote_insn (insn)) != 0
-	      && GET_CODE (temp) == INSN
-	      && REG_NOTES (temp) == 0
-	      && (temp3 = next_nonnote_insn (temp)) != 0
-	      && GET_CODE (temp3) == INSN
-	      && REG_NOTES (temp3) == 0
-	      && (reallabelprev == temp3
-		  || ((temp2 = next_active_insn (temp3)) != 0
-		      && simplejump_p (temp2)
-		      && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
-	      && (temp1 = single_set (temp)) != 0
-	      && (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
-	      && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
-	      && (! SMALL_REGISTER_CLASSES
-		  || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
-	      && ! side_effects_p (SET_SRC (temp1))
-	      && ! may_trap_p (SET_SRC (temp1))
-	      && rtx_cost (SET_SRC (temp1), SET) < 10
-	      && (temp4 = single_set (temp3)) != 0
-	      && rtx_equal_p (SET_DEST (temp4), temp2)
-	      && ! side_effects_p (SET_SRC (temp4))
-	      && ! may_trap_p (SET_SRC (temp4))
-	      && rtx_cost (SET_SRC (temp4), SET) < 10)
-	    {
-	      rtx new = gen_reg_rtx (GET_MODE (temp2));
-
-	      if ((temp5 = find_insert_position (insn, temp))
-		  && (temp6 = find_insert_position (insn, temp3))
-		  && validate_change (temp, &SET_DEST (temp1), new, 0))
-		{
-		  /* Use the earliest of temp5 and temp6. */
-		  if (temp5 != insn)
-		    temp6 = temp5;
-		  next = emit_insn_after (gen_move_insn (temp2, new), insn);
-		  emit_insn_after_with_line_notes (PATTERN (temp),
-						   PREV_INSN (temp6), temp);
-		  emit_insn_after_with_line_notes
-		    (replace_rtx (PATTERN (temp3), temp2, new),
-		     PREV_INSN (temp6), temp3);
-		  delete_insn (temp);
-		  delete_insn (temp3);
-		  reallabelprev = prev_active_insn (JUMP_LABEL (insn));
-
-		  if (after_regscan)
-		    {
-		      reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
-		      old_max_reg = max_reg_num ();
-		    }
-		}
-	    }
-
-	  /* Finally, handle the case where two insns are used to 
-	     compute EXP but a temporary register is used.  Here we must
-	     ensure that the temporary register is not used anywhere else.  */
-
-	  if (! reload_completed
-	      && after_regscan
-	      && this_is_condjump && ! this_is_simplejump
-	      && BRANCH_COST >= 4
-	      && (temp = next_nonnote_insn (insn)) != 0
-	      && GET_CODE (temp) == INSN
-	      && REG_NOTES (temp) == 0
-	      && (temp3 = next_nonnote_insn (temp)) != 0
-	      && GET_CODE (temp3) == INSN
-	      && REG_NOTES (temp3) == 0
-	      && (reallabelprev == temp3
-		  || ((temp2 = next_active_insn (temp3)) != 0
-		      && simplejump_p (temp2)
-		      && JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
-	      && (temp1 = single_set (temp)) != 0
-	      && (temp5 = SET_DEST (temp1),
-		  (GET_CODE (temp5) == REG
-		   || (GET_CODE (temp5) == SUBREG
-		       && (temp5 = SUBREG_REG (temp5),
-			   GET_CODE (temp5) == REG))))
-	      && REGNO (temp5) >= FIRST_PSEUDO_REGISTER
-	      && REGNO_FIRST_UID (REGNO (temp5)) == INSN_UID (temp)
-	      && REGNO_LAST_UID (REGNO (temp5)) == INSN_UID (temp3)
-	      && ! side_effects_p (SET_SRC (temp1))
-	      && ! may_trap_p (SET_SRC (temp1))
-	      && rtx_cost (SET_SRC (temp1), SET) < 10
-	      && (temp4 = single_set (temp3)) != 0
-	      && (temp2 = SET_DEST (temp4), GET_CODE (temp2) == REG)
-	      && GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
-	      && (! SMALL_REGISTER_CLASSES
-		  || REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
-	      && rtx_equal_p (SET_DEST (temp4), temp2)
-	      && ! side_effects_p (SET_SRC (temp4))
-	      && ! may_trap_p (SET_SRC (temp4))
-	      && rtx_cost (SET_SRC (temp4), SET) < 10)
-	    {
-	      rtx new = gen_reg_rtx (GET_MODE (temp2));
-
-	      if ((temp5 = find_insert_position (insn, temp))
-		  && (temp6 = find_insert_position (insn, temp3))
-		  && validate_change (temp3, &SET_DEST (temp4), new, 0))
-		{
-		  /* Use the earliest of temp5 and temp6. */
-		  if (temp5 != insn)
-		    temp6 = temp5;
-		  next = emit_insn_after (gen_move_insn (temp2, new), insn);
-		  emit_insn_after_with_line_notes (PATTERN (temp),
-						   PREV_INSN (temp6), temp);
-		  emit_insn_after_with_line_notes (PATTERN (temp3),
-						   PREV_INSN (temp6), temp3);
-		  delete_insn (temp);
-		  delete_insn (temp3);
-		  reallabelprev = prev_active_insn (JUMP_LABEL (insn));
-
-		  if (after_regscan)
-		    {
-		      reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
-		      old_max_reg = max_reg_num ();
-		    }
-		}
-	    }
-#endif /* HAVE_cc0 */
-
-#ifdef HAVE_conditional_arithmetic
-	  /* ??? This is disabled in genconfig, as this simple-minded
-	     transformation can incredibly lengthen register lifetimes.
-
-	     Consider this example:
-
-		234 (set (pc)
-		      (if_then_else (ne (reg:DI 149) (const_int 0 [0x0]))
-		        (label_ref 248) (pc)))
-		237 (set (reg/i:DI 0 $0) (const_int 1 [0x1]))
-		239 (set (pc) (label_ref 2382))
-		248 (code_label ("yybackup"))
-
-	     This will be transformed to:
-
-		237 (set (reg/i:DI 0 $0)
-		      (if_then_else:DI (eq (reg:DI 149) (const_int 0 [0x0]))
-		        (const_int 1 [0x1]) (reg/i:DI 0 $0)))
-		239 (set (pc)
-		      (if_then_else (eq (reg:DI 149) (const_int 0 [0x0]))
-		        (label_ref 2382) (pc)))
-
-	     which, from this narrow viewpoint looks fine.  Except that
-	     between this and 3 other ocurrences of the same pattern, $0
-	     is now live for basically the entire function, and we'll 
-	     get an abort in caller_save.
-
-	     Any replacement for this code should recall that a set of
-	     a register that is not live need not, and indeed should not,
-	     be conditionalized.  Either that, or delay the transformation
-	     until after register allocation.  */
-
-	  /* See if this is a conditional jump around a small number of
-	     instructions that we can conditionalize.  Don't do this before
-	     the initial CSE pass or after reload.
-
-	     We reject any insns that have side effects or may trap.
-	     Strictly speaking, this is not needed since the machine may
-	     support conditionalizing these too, but we won't deal with that
-	     now.  Specifically, this means that we can't conditionalize a 
-	     CALL_INSN, which some machines, such as the ARC, can do, but
-	     this is a very minor optimization.  */
-	  if (this_is_condjump && ! this_is_simplejump
-	      && cse_not_expected && ! reload_completed
-	      && BRANCH_COST > 2
-	      && can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (insn)), 0),
-					   insn))
-	    {
-	      rtx ourcond = XEXP (SET_SRC (PATTERN (insn)), 0);
-	      int num_insns = 0;
-	      char *storage = (char *) oballoc (0);
-	      int last_insn = 0, failed = 0;
-	      rtx changed_jump = 0;
-
-	      ourcond = gen_rtx (reverse_condition (GET_CODE (ourcond)),
-				 VOIDmode, XEXP (ourcond, 0),
-				 XEXP (ourcond, 1));
-
-	      /* Scan forward BRANCH_COST real insns looking for the JUMP_LABEL
-		 of this insn.  We see if we think we can conditionalize the
-		 insns we pass.  For now, we only deal with insns that have
-		 one SET.  We stop after an insn that modifies anything in
-		 OURCOND, if we have too many insns, or if we have an insn
-		 with a side effect or that may trip.  Note that we will
-		 be modifying any unconditional jumps we encounter to be
-		 conditional; this will have the effect of also doing this
-		 optimization on the "else" the next time around.  */
-	      for (temp1 = NEXT_INSN (insn);
-		   num_insns <= BRANCH_COST && ! failed && temp1 != 0
-		   && GET_CODE (temp1) != CODE_LABEL;
-		   temp1 = NEXT_INSN (temp1))
-		{
-		  /* Ignore everything but an active insn.  */
-		  if (GET_RTX_CLASS (GET_CODE (temp1)) != 'i'
-		      || GET_CODE (PATTERN (temp1)) == USE
-		      || GET_CODE (PATTERN (temp1)) == CLOBBER)
-		    continue;
-
-		  /* If this was an unconditional jump, record it since we'll
-		     need to remove the BARRIER if we succeed.  We can only
-		     have one such jump since there must be a label after
-		     the BARRIER and it's either ours, in which case it's the
-		     only one or some other, in which case we'd fail.
-		     Likewise if it's a CALL_INSN followed by a BARRIER.  */
-
-		  if (simplejump_p (temp1)
-		      || (GET_CODE (temp1) == CALL_INSN
-			  && NEXT_INSN (temp1) != 0
-			  && GET_CODE (NEXT_INSN (temp1)) == BARRIER))
-		    {
-		      if (changed_jump == 0)
-			changed_jump = temp1;
-		      else
-			changed_jump
-			  = gen_rtx_INSN_LIST (VOIDmode, temp1, changed_jump);
-		    }
-
-		  /* See if we are allowed another insn and if this insn
-		     if one we think we may be able to handle.  */
-		  if (++num_insns > BRANCH_COST
-		      || last_insn
-		      || (((temp2 = single_set (temp1)) == 0
-			   || side_effects_p (SET_SRC (temp2))
-			   || may_trap_p (SET_SRC (temp2)))
-			  && GET_CODE (temp1) != CALL_INSN))
-		      failed = 1;
-		  else if (temp2 != 0)
-		    validate_change (temp1, &SET_SRC (temp2),
-				     gen_rtx_IF_THEN_ELSE
-				     (GET_MODE (SET_DEST (temp2)),
-				      copy_rtx (ourcond),
-				      SET_SRC (temp2), SET_DEST (temp2)),
-				     1);
-		  else
-		    {
-		      /* This is a CALL_INSN that doesn't have a SET.  */
-		      rtx *call_loc = &PATTERN (temp1);
-
-		      if (GET_CODE (*call_loc) == PARALLEL)
-			call_loc = &XVECEXP (*call_loc, 0, 0);
-
-		      validate_change (temp1, call_loc,
-				       gen_rtx_IF_THEN_ELSE
-				       (VOIDmode, copy_rtx (ourcond),
-					*call_loc, const0_rtx),
-				       1);
-		    }
-
-
-		  if (modified_in_p (ourcond, temp1))
-		    last_insn = 1;
-		}
-
-	      /* If we've reached our jump label, haven't failed, and all
-		 the changes above are valid, we can delete this jump
-		 insn.  Also remove a BARRIER after any jump that used
-		 to be unconditional and remove any REG_EQUAL or REG_EQUIV
-		 that might have previously been present on insns we
-		 made conditional.  */
-	      if (temp1 == JUMP_LABEL (insn) && ! failed
-		  && apply_change_group ())
-		{
-		  for (temp1 = NEXT_INSN (insn); temp1 != JUMP_LABEL (insn);
-		       temp1 = NEXT_INSN (temp1))
-		    if (GET_RTX_CLASS (GET_CODE (temp1)) == 'i')
-		      for (temp2 = REG_NOTES (temp1); temp2 != 0;
-			   temp2 = XEXP (temp2, 1))
-			if (REG_NOTE_KIND (temp2) == REG_EQUAL
-			    || REG_NOTE_KIND (temp2) == REG_EQUIV)
-			  remove_note (temp1, temp2);
-
-		  if (changed_jump != 0)
-		    {
-		      while (GET_CODE (changed_jump) == INSN_LIST)
-			{
-			  delete_barrier (NEXT_INSN (XEXP (changed_jump, 0)));
-			  changed_jump = XEXP (changed_jump, 1);
-			}
-
-		      delete_barrier (NEXT_INSN (changed_jump));
-		    }
-
-		  delete_insn (insn);
-		  changed = 1;
-		  continue;
-		}
-	      else
-		{
-		  cancel_changes (0);
-		  obfree (storage);
-		}
-	    }
-#endif
-	  /* If branches are expensive, convert
-	        if (foo) bar++;    to    bar += (foo != 0);
-	     and similarly for "bar--;" 
-
-	     INSN is the conditional branch around the arithmetic.  We set:
-
-	     TEMP is the arithmetic insn.
-	     TEMP1 is the SET doing the arithmetic.
-	     TEMP2 is the operand being incremented or decremented.
-	     TEMP3 to the condition being tested.
-	     TEMP4 to the earliest insn used to find the condition.  */
-
-	  if ((BRANCH_COST >= 2
-#ifdef HAVE_incscc
-	       || HAVE_incscc
-#endif
-#ifdef HAVE_decscc
-	       || HAVE_decscc
-#endif
-	      )
-	      && ! reload_completed
-	      && this_is_condjump && ! this_is_simplejump
-	      && (temp = next_nonnote_insn (insn)) != 0
-	      && (temp1 = single_set (temp)) != 0
-	      && (temp2 = SET_DEST (temp1),
-		  GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT)
-	      && GET_CODE (SET_SRC (temp1)) == PLUS
-	      && (XEXP (SET_SRC (temp1), 1) == const1_rtx
-		  || XEXP (SET_SRC (temp1), 1) == constm1_rtx)
-	      && rtx_equal_p (temp2, XEXP (SET_SRC (temp1), 0))
-	      && ! side_effects_p (temp2)
-	      && ! may_trap_p (temp2)
-	      /* INSN must either branch to the insn after TEMP or the insn
-		 after TEMP must branch to the same place as INSN.  */
-	      && (reallabelprev == temp
-		  || ((temp3 = next_active_insn (temp)) != 0
-		      && simplejump_p (temp3)
-		      && JUMP_LABEL (temp3) == JUMP_LABEL (insn)))
-	      && (temp3 = get_condition (insn, &temp4)) != 0
-	      /* We must be comparing objects whose modes imply the size.
-		 We could handle BLKmode if (1) emit_store_flag could
-		 and (2) we could find the size reliably.  */
-	      && GET_MODE (XEXP (temp3, 0)) != BLKmode
-	      && can_reverse_comparison_p (temp3, insn))
-	    {
-	      rtx temp6, target = 0, seq, init_insn = 0, init = temp2;
-	      enum rtx_code code = reverse_condition (GET_CODE (temp3));
-
-	      start_sequence ();
-
-	      /* It must be the case that TEMP2 is not modified in the range
-		 [TEMP4, INSN).  The one exception we make is if the insn
-		 before INSN sets TEMP2 to something which is also unchanged
-		 in that range.  In that case, we can move the initialization
-		 into our sequence.  */
-
-	      if ((temp5 = prev_active_insn (insn)) != 0
-		  && no_labels_between_p (temp5, insn)
-		  && GET_CODE (temp5) == INSN
-		  && (temp6 = single_set (temp5)) != 0
-		  && rtx_equal_p (temp2, SET_DEST (temp6))
-		  && (CONSTANT_P (SET_SRC (temp6))
-		      || GET_CODE (SET_SRC (temp6)) == REG
-		      || GET_CODE (SET_SRC (temp6)) == SUBREG))
-		{
-		  emit_insn (PATTERN (temp5));
-		  init_insn = temp5;
-		  init = SET_SRC (temp6);
-		}
-
-	      if (CONSTANT_P (init)
-		  || ! reg_set_between_p (init, PREV_INSN (temp4), insn))
-		target = emit_store_flag (gen_reg_rtx (GET_MODE (temp2)), code,
-					  XEXP (temp3, 0), XEXP (temp3, 1),
-					  VOIDmode,
-					  (code == LTU || code == LEU
-					   || code == GTU || code == GEU), 1);
-
-	      /* If we can do the store-flag, do the addition or
-		 subtraction.  */
-
-	      if (target)
-		target = expand_binop (GET_MODE (temp2),
-				       (XEXP (SET_SRC (temp1), 1) == const1_rtx
-					? add_optab : sub_optab),
-				       temp2, target, temp2, 0, OPTAB_WIDEN);
-
-	      if (target != 0)
-		{
-		  /* Put the result back in temp2 in case it isn't already.
-		     Then replace the jump, possible a CC0-setting insn in
-		     front of the jump, and TEMP, with the sequence we have
-		     made.  */
-
-		  if (target != temp2)
-		    emit_move_insn (temp2, target);
-
-		  seq = get_insns ();
-		  end_sequence ();
-
-		  emit_insns_before (seq, temp4);
-		  delete_insn (temp);
-
-		  if (init_insn)
-		    delete_insn (init_insn);
-
-		  next = NEXT_INSN (insn);
-#ifdef HAVE_cc0
-		  delete_insn (prev_nonnote_insn (insn));
-#endif
-		  delete_insn (insn);
-
-		  if (after_regscan)
-		    {
-		      reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
-		      old_max_reg = max_reg_num ();
-		    }
-
-		  changed = 1;
-		  continue;
-		}
-	      else
-		end_sequence ();
-	    }
-
-	  /* Try to use a conditional move (if the target has them), or a
-	     store-flag insn.  If the target has conditional arithmetic as
-	     well as conditional move, the above code will have done something.
-	     Note that we prefer the above code since it is more general: the
-	     code below can make changes that require work to undo.
-
-	     The general case here is:
-
-	     1) x = a; if (...) x = b; and
-	     2) if (...) x = b;
-
-	     If the jump would be faster, the machine should not have defined
-	     the movcc or scc insns!.  These cases are often made by the
-	     previous optimization.
-
-	     The second case is treated as  x = x; if (...) x = b;.
-
-	     INSN here is the jump around the store.  We set:
-
-	     TEMP to the "x op= b;" insn.
-	     TEMP1 to X.
-	     TEMP2 to B.
-	     TEMP3 to A (X in the second case).
-	     TEMP4 to the condition being tested.
-	     TEMP5 to the earliest insn used to find the condition.
-	     TEMP6 to the SET of TEMP.  */
-
-	  if (/* We can't do this after reload has completed.  */
-	      ! reload_completed
-#ifdef HAVE_conditional_arithmetic
-	      /* Defer this until after CSE so the above code gets the
-		 first crack at it.  */
-	      && cse_not_expected
-#endif
-	      && this_is_condjump && ! this_is_simplejump
-	      /* Set TEMP to the "x = b;" insn.  */
-	      && (temp = next_nonnote_insn (insn)) != 0
-	      && GET_CODE (temp) == INSN
-	      && (temp6 = single_set (temp)) != NULL_RTX
-	      && GET_CODE (temp1 = SET_DEST (temp6)) == REG
-	      && (! SMALL_REGISTER_CLASSES
-		  || REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
-	      && ! side_effects_p (temp2 = SET_SRC (temp6))
-	      && ! may_trap_p (temp2)
-	      /* Allow either form, but prefer the former if both apply. 
-		 There is no point in using the old value of TEMP1 if
-		 it is a register, since cse will alias them.  It can
-		 lose if the old value were a hard register since CSE
-		 won't replace hard registers.  Avoid using TEMP3 if
-		 small register classes and it is a hard register.  */
-	      && (((temp3 = reg_set_last (temp1, insn)) != 0
-		   && ! (SMALL_REGISTER_CLASSES && GET_CODE (temp3) == REG
-			 && REGNO (temp3) < FIRST_PSEUDO_REGISTER))
-		  /* Make the latter case look like  x = x; if (...) x = b;  */
-		  || (temp3 = temp1, 1))
-	      /* INSN must either branch to the insn after TEMP or the insn
-		 after TEMP must branch to the same place as INSN.  */
-	      && (reallabelprev == temp
-		  || ((temp4 = next_active_insn (temp)) != 0
-		      && simplejump_p (temp4)
-		      && JUMP_LABEL (temp4) == JUMP_LABEL (insn)))
-	      && (temp4 = get_condition (insn, &temp5)) != 0
-	      /* We must be comparing objects whose modes imply the size.
-		 We could handle BLKmode if (1) emit_store_flag could
-		 and (2) we could find the size reliably.  */
-	      && GET_MODE (XEXP (temp4, 0)) != BLKmode
-	      /* Even if branches are cheap, the store_flag optimization
-		 can win when the operation to be performed can be
-		 expressed directly.  */
-#ifdef HAVE_cc0
-	      /* If the previous insn sets CC0 and something else, we can't
-		 do this since we are going to delete that insn.  */
-
-	      && ! ((temp6 = prev_nonnote_insn (insn)) != 0
-		    && GET_CODE (temp6) == INSN
-		    && (sets_cc0_p (PATTERN (temp6)) == -1
-			|| (sets_cc0_p (PATTERN (temp6)) == 1
-			    && FIND_REG_INC_NOTE (temp6, NULL_RTX))))
-#endif
-	      )
-	    {
-#ifdef HAVE_conditional_move
-	      /* First try a conditional move.  */
-	      {
-		enum rtx_code code = GET_CODE (temp4);
-		rtx var = temp1;
-		rtx cond0, cond1, aval, bval;
-		rtx target, new_insn;
-
-		/* Copy the compared variables into cond0 and cond1, so that
-		   any side effects performed in or after the old comparison,
-		   will not affect our compare which will come later.  */
-		/* ??? Is it possible to just use the comparison in the jump
-		   insn?  After all, we're going to delete it.  We'd have
-		   to modify emit_conditional_move to take a comparison rtx
-		   instead or write a new function.  */
-
-		/* We want the target to be able to simplify comparisons with
-		   zero (and maybe other constants as well), so don't create
-		   pseudos for them.  There's no need to either.  */
-		if (GET_CODE (XEXP (temp4, 0)) == CONST_INT
-		    || GET_CODE (XEXP (temp4, 0)) == CONST_DOUBLE)
-		  cond0 = XEXP (temp4, 0);
-		else
-		  cond0 = gen_reg_rtx (GET_MODE (XEXP (temp4, 0)));
-
-		if (GET_CODE (XEXP (temp4, 1)) == CONST_INT
-		    || GET_CODE (XEXP (temp4, 1)) == CONST_DOUBLE)
-		  cond1 = XEXP (temp4, 1);
-		else
-		  cond1 = gen_reg_rtx (GET_MODE (XEXP (temp4, 1)));
-
-		/* Careful about copying these values -- an IOR or what may
-		   need to do other things, like clobber flags.  */
-		/* ??? Assume for the moment that AVAL is ok.  */
-		aval = temp3;
-
-		start_sequence ();
-
-		/* We're dealing with a single_set insn with no side effects
-		   on SET_SRC.  We do need to be reasonably certain that if
-		   we need to force BVAL into a register that we won't 
-		   clobber the flags -- general_operand should suffice.  */
-		if (general_operand (temp2, GET_MODE (var)))
-		  bval = temp2;
-		else
-		  {
-		    bval = gen_reg_rtx (GET_MODE (var));
-		    new_insn = copy_rtx (temp);
-		    temp6 = single_set (new_insn);
-		    SET_DEST (temp6) = bval;
-		    emit_insn (PATTERN (new_insn));
-		  }
-
-		target = emit_conditional_move (var, code,
-						cond0, cond1, VOIDmode,
-						aval, bval, GET_MODE (var),
-						(code == LTU || code == GEU
-						 || code == LEU || code == GTU));
-
-		if (target)
-		  {
-		    rtx seq1, seq2, last;
-		    int copy_ok;
-
-		    /* Save the conditional move sequence but don't emit it
-		       yet.  On some machines, like the alpha, it is possible
-		       that temp5 == insn, so next generate the sequence that
-		       saves the compared values and then emit both
-		       sequences ensuring seq1 occurs before seq2.  */
-		    seq2 = get_insns ();
-		    end_sequence ();
-
-		    /* "Now that we can't fail..."  Famous last words.
-		       Generate the copy insns that preserve the compared
-		       values.  */
-		    start_sequence ();
-		    emit_move_insn (cond0, XEXP (temp4, 0));
-		    if (cond1 != XEXP (temp4, 1))
-		      emit_move_insn (cond1, XEXP (temp4, 1));
-		    seq1 = get_insns ();
-		    end_sequence ();
-
-		    /* Validate the sequence -- this may be some weird
-		       bit-extract-and-test instruction for which there
-		       exists no complimentary bit-extract insn.  */
-		    copy_ok = 1;
-		    for (last = seq1; last ; last = NEXT_INSN (last))
-		      if (recog_memoized (last) < 0)
-			{
-			  copy_ok = 0;
-			  break;
-			}
-
-		    if (copy_ok)
-		      {
-		        emit_insns_before (seq1, temp5);
-
-		        /* Insert conditional move after insn, to be sure
-			   that the jump and a possible compare won't be
-			   separated.  */
-		        last = emit_insns_after (seq2, insn);
-
-		        /* ??? We can also delete the insn that sets X to A.
-		           Flow will do it too though.  */
-		        delete_insn (temp);
-		        next = NEXT_INSN (insn);
-		        delete_jump (insn);
-
-		        if (after_regscan)
-		          {
-			    reg_scan_update (seq1, NEXT_INSN (last),
-					     old_max_reg);
-			    old_max_reg = max_reg_num ();
-		          }
-
-		        changed = 1;
-		        continue;
-		      }
-		  }
-		else
-		  end_sequence ();
-	      }
-#endif
-
-	      /* That didn't work, try a store-flag insn.
-
-		 We further divide the cases into:
-
-		 1) x = a; if (...) x = b; and either A or B is zero,
-		 2) if (...) x = 0; and jumps are expensive,
-		 3) x = a; if (...) x = b; and A and B are constants where all
-		 the set bits in A are also set in B and jumps are expensive,
-		 4) x = a; if (...) x = b; and A and B non-zero, and jumps are
-		 more expensive, and
-		 5) if (...) x = b; if jumps are even more expensive.  */
-
-	      if (GET_MODE_CLASS (GET_MODE (temp1)) == MODE_INT
-		  /* We will be passing this as operand into expand_and.  No
-		     good if it's not valid as an operand.  */
-		  && general_operand (temp2, GET_MODE (temp2))
-		  && ((GET_CODE (temp3) == CONST_INT)
-		      /* Make the latter case look like
-			 x = x; if (...) x = 0;  */
-		      || (temp3 = temp1,
-			  ((BRANCH_COST >= 2
-			    && temp2 == const0_rtx)
-			   || BRANCH_COST >= 3)))
-		  /* If B is zero, OK; if A is zero, can only do (1) if we
-		     can reverse the condition.  See if (3) applies possibly
-		     by reversing the condition.  Prefer reversing to (4) when
-		     branches are very expensive.  */
-		  && (((BRANCH_COST >= 2
-			|| STORE_FLAG_VALUE == -1
-			|| (STORE_FLAG_VALUE == 1
-			 /* Check that the mask is a power of two,
-			    so that it can probably be generated
-			    with a shift.  */
-			    && GET_CODE (temp3) == CONST_INT
-			    && exact_log2 (INTVAL (temp3)) >= 0))
-		       && (reversep = 0, temp2 == const0_rtx))
-		      || ((BRANCH_COST >= 2
-			   || STORE_FLAG_VALUE == -1
-			   || (STORE_FLAG_VALUE == 1
-			       && GET_CODE (temp2) == CONST_INT
-			       && exact_log2 (INTVAL (temp2)) >= 0))
-			  && temp3 == const0_rtx
-			  && (reversep = can_reverse_comparison_p (temp4, insn)))
-		      || (BRANCH_COST >= 2
-			  && GET_CODE (temp2) == CONST_INT
-			  && GET_CODE (temp3) == CONST_INT
-			  && ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp2)
-			      || ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp3)
-				  && (reversep = can_reverse_comparison_p (temp4,
-									   insn)))))
-		      || BRANCH_COST >= 3)
-		  )
-		{
-		  enum rtx_code code = GET_CODE (temp4);
-		  rtx uval, cval, var = temp1;
-		  int normalizep;
-		  rtx target;
-
-		  /* If necessary, reverse the condition.  */
-		  if (reversep)
-		    code = reverse_condition (code), uval = temp2, cval = temp3;
-		  else
-		    uval = temp3, cval = temp2;
-
-		  /* If CVAL is non-zero, normalize to -1.  Otherwise, if UVAL
-		     is the constant 1, it is best to just compute the result
-		     directly.  If UVAL is constant and STORE_FLAG_VALUE
-		     includes all of its bits, it is best to compute the flag
-		     value unnormalized and `and' it with UVAL.  Otherwise,
-		     normalize to -1 and `and' with UVAL.  */
-		  normalizep = (cval != const0_rtx ? -1
-				: (uval == const1_rtx ? 1
-				   : (GET_CODE (uval) == CONST_INT
-				      && (INTVAL (uval) & ~STORE_FLAG_VALUE) == 0)
-				   ? 0 : -1));
-
-		  /* We will be putting the store-flag insn immediately in
-		     front of the comparison that was originally being done,
-		     so we know all the variables in TEMP4 will be valid.
-		     However, this might be in front of the assignment of
-		     A to VAR.  If it is, it would clobber the store-flag
-		     we will be emitting.
-
-		     Therefore, emit into a temporary which will be copied to
-		     VAR immediately after TEMP.  */
-
-		  start_sequence ();
-		  target = emit_store_flag (gen_reg_rtx (GET_MODE (var)), code,
-					    XEXP (temp4, 0), XEXP (temp4, 1),
-					    VOIDmode,
-					    (code == LTU || code == LEU 
-					     || code == GEU || code == GTU),
-					    normalizep);
-		  if (target)
-		    {
-		      rtx seq;
-		      rtx before = insn;
-
-		      seq = get_insns ();
-		      end_sequence ();
-
-		      /* Put the store-flag insns in front of the first insn
-			 used to compute the condition to ensure that we
-			 use the same values of them as the current 
-			 comparison.  However, the remainder of the insns we
-			 generate will be placed directly in front of the
-			 jump insn, in case any of the pseudos we use
-			 are modified earlier.  */
-
-		      emit_insns_before (seq, temp5);
-
-		      start_sequence ();
-
-		      /* Both CVAL and UVAL are non-zero.  */
-		      if (cval != const0_rtx && uval != const0_rtx)
-			{
-			  rtx tem1, tem2;
-
-			  tem1 = expand_and (uval, target, NULL_RTX);
-			  if (GET_CODE (cval) == CONST_INT
-			      && GET_CODE (uval) == CONST_INT
-			      && (INTVAL (cval) & INTVAL (uval)) == INTVAL (cval))
-			    tem2 = cval;
-			  else
-			    {
-			      tem2 = expand_unop (GET_MODE (var), one_cmpl_optab,
-						  target, NULL_RTX, 0);
-			      tem2 = expand_and (cval, tem2,
-						 (GET_CODE (tem2) == REG
-						  ? tem2 : 0));
-			    }
-
-			  /* If we usually make new pseudos, do so here.  This
-			     turns out to help machines that have conditional
-			     move insns.  */
-			  /* ??? Conditional moves have already been handled.
-			     This may be obsolete.  */
-
-			  if (flag_expensive_optimizations)
-			    target = 0;
-
-			  target = expand_binop (GET_MODE (var), ior_optab,
-						 tem1, tem2, target,
-						 1, OPTAB_WIDEN);
-			}
-		      else if (normalizep != 1)
-			{
-			  /* We know that either CVAL or UVAL is zero.  If
-			     UVAL is zero, negate TARGET and `and' with CVAL.
-			     Otherwise, `and' with UVAL.  */
-			  if (uval == const0_rtx)
-			    {
-			      target = expand_unop (GET_MODE (var), one_cmpl_optab,
-						    target, NULL_RTX, 0);
-			      uval = cval;
-			    }
-
-			  target = expand_and (uval, target,
-					       (GET_CODE (target) == REG
-						&& ! preserve_subexpressions_p ()
-						? target : NULL_RTX));
-			}
-		  
-		      emit_move_insn (var, target);
-		      seq = get_insns ();
-		      end_sequence ();
-#ifdef HAVE_cc0
-		      /* If INSN uses CC0, we must not separate it from the
-			 insn that sets cc0.  */
-		      if (reg_mentioned_p (cc0_rtx, PATTERN (before)))
-			before = prev_nonnote_insn (before);
-#endif
-		      emit_insns_before (seq, before);
-
-		      delete_insn (temp);
-		      next = NEXT_INSN (insn);
-		      delete_jump (insn);
-
-		      if (after_regscan)
-			{
-			  reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
-			  old_max_reg = max_reg_num ();
-			}
-
-		      changed = 1;
-		      continue;
-		    }
-		  else
-		    end_sequence ();
-		}
-	    }
-
-
-	  /* Simplify   if (...) x = 1; else {...}  if (x) ...
-	     We recognize this case scanning backwards as well.
-
-	     TEMP is the assignment to x;
-	     TEMP1 is the label at the head of the second if.  */
-	  /* ?? This should call get_condition to find the values being
-	     compared, instead of looking for a COMPARE insn when HAVE_cc0
-	     is not defined.  This would allow it to work on the m88k.  */
-	  /* ?? This optimization is only safe before cse is run if HAVE_cc0
-	     is not defined and the condition is tested by a separate compare
-	     insn.  This is because the code below assumes that the result
-	     of the compare dies in the following branch.
-
-	     Not only that, but there might be other insns between the
-	     compare and branch whose results are live.  Those insns need
-	     to be executed.
-
-	     A way to fix this is to move the insns at JUMP_LABEL (insn)
-	     to before INSN.  If we are running before flow, they will
-	     be deleted if they aren't needed.   But this doesn't work
-	     well after flow.
-
-	     This is really a special-case of jump threading, anyway.  The
-	     right thing to do is to replace this and jump threading with
-	     much simpler code in cse.
-
-	     This code has been turned off in the non-cc0 case in the
-	     meantime.  */
-
-#ifdef HAVE_cc0
-	  else if (this_is_simplejump
-		   /* Safe to skip USE and CLOBBER insns here
-		      since they will not be deleted.  */
-		   && (temp = prev_active_insn (insn))
-		   && no_labels_between_p (temp, insn)
-		   && GET_CODE (temp) == INSN
-		   && GET_CODE (PATTERN (temp)) == SET
-		   && GET_CODE (SET_DEST (PATTERN (temp))) == REG
-		   && CONSTANT_P (SET_SRC (PATTERN (temp)))
-		   && (temp1 = next_active_insn (JUMP_LABEL (insn)))
-		   /* If we find that the next value tested is `x'
-		      (TEMP1 is the insn where this happens), win.  */
-		   && GET_CODE (temp1) == INSN
-		   && GET_CODE (PATTERN (temp1)) == SET
-#ifdef HAVE_cc0
-		   /* Does temp1 `tst' the value of x?  */
-		   && SET_SRC (PATTERN (temp1)) == SET_DEST (PATTERN (temp))
-		   && SET_DEST (PATTERN (temp1)) == cc0_rtx
-		   && (temp1 = next_nonnote_insn (temp1))
-#else
-		   /* Does temp1 compare the value of x against zero?  */
-		   && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
-		   && XEXP (SET_SRC (PATTERN (temp1)), 1) == const0_rtx
-		   && (XEXP (SET_SRC (PATTERN (temp1)), 0)
-		       == SET_DEST (PATTERN (temp)))
-		   && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
-		   && (temp1 = find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
-#endif
-		   && condjump_p (temp1))
-	    {
-	      /* Get the if_then_else from the condjump.  */
-	      rtx choice = SET_SRC (PATTERN (temp1));
-	      if (GET_CODE (choice) == IF_THEN_ELSE)
-		{
-		  enum rtx_code code = GET_CODE (XEXP (choice, 0));
-		  rtx val = SET_SRC (PATTERN (temp));
-		  rtx cond
-		    = simplify_relational_operation (code, GET_MODE (SET_DEST (PATTERN (temp))),
-						     val, const0_rtx);
-		  rtx ultimate;
-
-		  if (cond == const_true_rtx)
-		    ultimate = XEXP (choice, 1);
-		  else if (cond == const0_rtx)
-		    ultimate = XEXP (choice, 2);
-		  else
-		    ultimate = 0;
-
-		  if (ultimate == pc_rtx)
-		    ultimate = get_label_after (temp1);
-		  else if (ultimate && GET_CODE (ultimate) != RETURN)
-		    ultimate = XEXP (ultimate, 0);
-
-		  if (ultimate && JUMP_LABEL(insn) != ultimate)
-		    changed |= redirect_jump (insn, ultimate);
-		}
-	    }
-#endif
-
-#if 0
-	  /* @@ This needs a bit of work before it will be right.
-
-	     Any type of comparison can be accepted for the first and
-	     second compare.  When rewriting the first jump, we must
-	     compute the what conditions can reach label3, and use the
-	     appropriate code.  We can not simply reverse/swap the code
-	     of the first jump.  In some cases, the second jump must be
-	     rewritten also.
-
-	     For example, 
-	     <  == converts to >  ==
-	     <  != converts to ==  >
-	     etc.
-
-	     If the code is written to only accept an '==' test for the second
-	     compare, then all that needs to be done is to swap the condition
-	     of the first branch.
-
-	     It is questionable whether we want this optimization anyways,
-	     since if the user wrote code like this because he/she knew that
-	     the jump to label1 is taken most of the time, then rewriting
-	     this gives slower code.  */
-	  /* @@ This should call get_condition to find the values being
-	     compared, instead of looking for a COMPARE insn when HAVE_cc0
-	     is not defined.  This would allow it to work on the m88k.  */
-	  /* @@ This optimization is only safe before cse is run if HAVE_cc0
-	     is not defined and the condition is tested by a separate compare
-	     insn.  This is because the code below assumes that the result
-	     of the compare dies in the following branch.  */
-
-	  /* Simplify  test a ~= b
-		       condjump label1;
-		       test a == b
-		       condjump label2;
-		       jump label3;
-		       label1:
-
-	     rewriting as
-		       test a ~~= b
-		       condjump label3
-		       test a == b
-		       condjump label2
-		       label1:
-
-	     where ~= is an inequality, e.g. >, and ~~= is the swapped
-	     inequality, e.g. <.
-
-	     We recognize this case scanning backwards.
-
-	     TEMP is the conditional jump to `label2';
-	     TEMP1 is the test for `a == b';
-	     TEMP2 is the conditional jump to `label1';
-	     TEMP3 is the test for `a ~= b'.  */
-	  else if (this_is_simplejump
-		   && (temp = prev_active_insn (insn))
-		   && no_labels_between_p (temp, insn)
-		   && condjump_p (temp)
-		   && (temp1 = prev_active_insn (temp))
-		   && no_labels_between_p (temp1, temp)
-		   && GET_CODE (temp1) == INSN
-		   && GET_CODE (PATTERN (temp1)) == SET
-#ifdef HAVE_cc0
-		   && sets_cc0_p (PATTERN (temp1)) == 1
-#else
-		   && GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
-		   && GET_CODE (SET_DEST (PATTERN (temp1))) == REG
-		   && (temp == find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
-#endif
-		   && (temp2 = prev_active_insn (temp1))
-		   && no_labels_between_p (temp2, temp1)
-		   && condjump_p (temp2)
-		   && JUMP_LABEL (temp2) == next_nonnote_insn (NEXT_INSN (insn))
-		   && (temp3 = prev_active_insn (temp2))
-		   && no_labels_between_p (temp3, temp2)
-		   && GET_CODE (PATTERN (temp3)) == SET
-		   && rtx_equal_p (SET_DEST (PATTERN (temp3)),
-				   SET_DEST (PATTERN (temp1)))
-		   && rtx_equal_p (SET_SRC (PATTERN (temp1)),
-				   SET_SRC (PATTERN (temp3)))
-		   && ! inequality_comparisons_p (PATTERN (temp))
-		   && inequality_comparisons_p (PATTERN (temp2)))
-	    {
-	      rtx fallthrough_label = JUMP_LABEL (temp2);
-
-	      ++LABEL_NUSES (fallthrough_label);
-	      if (swap_jump (temp2, JUMP_LABEL (insn)))
-		{
-		  delete_insn (insn);
-		  changed = 1;
-		}
-
-	      if (--LABEL_NUSES (fallthrough_label) == 0)
-		delete_insn (fallthrough_label);
-	    }
-#endif
-	  /* Simplify  if (...) {... x = 1;} if (x) ...
-
-	     We recognize this case backwards.
-
-	     TEMP is the test of `x';
-	     TEMP1 is the assignment to `x' at the end of the
-	     previous statement.  */
-	  /* @@ This should call get_condition to find the values being
-	     compared, instead of looking for a COMPARE insn when HAVE_cc0
-	     is not defined.  This would allow it to work on the m88k.  */
-	  /* @@ This optimization is only safe before cse is run if HAVE_cc0
-	     is not defined and the condition is tested by a separate compare
-	     insn.  This is because the code below assumes that the result
-	     of the compare dies in the following branch.  */
-
-	  /* ??? This has to be turned off.  The problem is that the
-	     unconditional jump might indirectly end up branching to the
-	     label between TEMP1 and TEMP.  We can't detect this, in general,
-	     since it may become a jump to there after further optimizations.
-	     If that jump is done, it will be deleted, so we will retry
-	     this optimization in the next pass, thus an infinite loop.
-
-	     The present code prevents this by putting the jump after the
-	     label, but this is not logically correct.  */
-#if 0
-	  else if (this_is_condjump
-		   /* Safe to skip USE and CLOBBER insns here
-		      since they will not be deleted.  */
-		   && (temp = prev_active_insn (insn))
-		   && no_labels_between_p (temp, insn)
-		   && GET_CODE (temp) == INSN
-		   && GET_CODE (PATTERN (temp)) == SET
-#ifdef HAVE_cc0
-		   && sets_cc0_p (PATTERN (temp)) == 1
-		   && GET_CODE (SET_SRC (PATTERN (temp))) == REG
-#else
-		   /* Temp must be a compare insn, we can not accept a register
-		      to register move here, since it may not be simply a
-		      tst insn.  */
-		   && GET_CODE (SET_SRC (PATTERN (temp))) == COMPARE
-		   && XEXP (SET_SRC (PATTERN (temp)), 1) == const0_rtx
-		   && GET_CODE (XEXP (SET_SRC (PATTERN (temp)), 0)) == REG
-		   && GET_CODE (SET_DEST (PATTERN (temp))) == REG
-		   && insn == find_next_ref (SET_DEST (PATTERN (temp)), temp)
-#endif
-		   /* May skip USE or CLOBBER insns here
-		      for checking for opportunity, since we
-		      take care of them later.  */
-		   && (temp1 = prev_active_insn (temp))
-		   && GET_CODE (temp1) == INSN
-		   && GET_CODE (PATTERN (temp1)) == SET
-#ifdef HAVE_cc0
-		   && SET_SRC (PATTERN (temp)) == SET_DEST (PATTERN (temp1))
-#else
-		   && (XEXP (SET_SRC (PATTERN (temp)), 0)
-		       == SET_DEST (PATTERN (temp1)))
-#endif
-		   && CONSTANT_P (SET_SRC (PATTERN (temp1)))
-		   /* If this isn't true, cse will do the job.  */
-		   && ! no_labels_between_p (temp1, temp))
-	    {
-	      /* Get the if_then_else from the condjump.  */
-	      rtx choice = SET_SRC (PATTERN (insn));
-	      if (GET_CODE (choice) == IF_THEN_ELSE
-		  && (GET_CODE (XEXP (choice, 0)) == EQ
-		      || GET_CODE (XEXP (choice, 0)) == NE))
-		{
-		  int want_nonzero = (GET_CODE (XEXP (choice, 0)) == NE);
-		  rtx last_insn;
-		  rtx ultimate;
-		  rtx p;
-
-		  /* Get the place that condjump will jump to
-		     if it is reached from here.  */
-		  if ((SET_SRC (PATTERN (temp1)) != const0_rtx)
-		      == want_nonzero)
-		    ultimate = XEXP (choice, 1);
-		  else
-		    ultimate = XEXP (choice, 2);
-		  /* Get it as a CODE_LABEL.  */
-		  if (ultimate == pc_rtx)
-		    ultimate = get_label_after (insn);
-		  else
-		    /* Get the label out of the LABEL_REF.  */
-		    ultimate = XEXP (ultimate, 0);
-
-		  /* Insert the jump immediately before TEMP, specifically
-		     after the label that is between TEMP1 and TEMP.  */
-		  last_insn = PREV_INSN (temp);
-
-		  /* If we would be branching to the next insn, the jump
-		     would immediately be deleted and the re-inserted in
-		     a subsequent pass over the code.  So don't do anything
-		     in that case.  */
-		  if (next_active_insn (last_insn)
-		      != next_active_insn (ultimate))
-		    {
-		      emit_barrier_after (last_insn);
-		      p = emit_jump_insn_after (gen_jump (ultimate),
-						last_insn);
-		      JUMP_LABEL (p) = ultimate;
-		      ++LABEL_NUSES (ultimate);
-		      if (INSN_UID (ultimate) < max_jump_chain
-			  && INSN_CODE (p) < max_jump_chain)
-			{
-			  jump_chain[INSN_UID (p)]
-			    = jump_chain[INSN_UID (ultimate)];
-			  jump_chain[INSN_UID (ultimate)] = p;
-			}
-		      changed = 1;
-		      continue;
-		    }
-		}
-	    }
-#endif
 #ifdef HAVE_trap
 	  /* Detect a conditional jump jumping over an unconditional trap.  */
-	  else if (HAVE_trap
-		   && this_is_condjump && ! this_is_simplejump
-		   && reallabelprev != 0
-		   && GET_CODE (reallabelprev) == INSN
-		   && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
-		   && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
-		   && prev_active_insn (reallabelprev) == insn
-		   && no_labels_between_p (insn, reallabelprev)
-		   && (temp2 = get_condition (insn, &temp4))
-		   && can_reverse_comparison_p (temp2, insn))
+	  if (HAVE_trap
+	      && this_is_condjump && ! this_is_simplejump
+	      && reallabelprev != 0
+	      && GET_CODE (reallabelprev) == INSN
+	      && GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
+	      && TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
+	      && prev_active_insn (reallabelprev) == insn
+	      && no_labels_between_p (insn, reallabelprev)
+	      && (temp2 = get_condition (insn, &temp4))
+	      && can_reverse_comparison_p (temp2, insn))
 	    {
 	      rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
 				       XEXP (temp2, 0), XEXP (temp2, 1),
@@ -5454,47 +4033,3 @@ rtx_equal_for_thread_p (x, y, yinsn)
     }
   return 1;
 }
-
-
-#if !defined(HAVE_cc0) && !defined(HAVE_conditional_arithmetic)
-/* Return the insn that NEW can be safely inserted in front of starting at
-   the jump insn INSN.  Return 0 if it is not safe to do this jump
-   optimization.  Note that NEW must contain a single set. */
-
-static rtx
-find_insert_position (insn, new)
-     rtx insn;
-     rtx new;
-{
-  int i;
-  rtx prev;
-
-  /* If NEW does not clobber, it is safe to insert NEW before INSN. */
-  if (GET_CODE (PATTERN (new)) != PARALLEL)
-    return insn;
-
-  for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
-    if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
-	&& reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
-				    insn))
-      break;
-
-  if (i < 0)
-    return insn;
-
-  /* There is a good chance that the previous insn PREV sets the thing
-     being clobbered (often the CC in a hard reg).  If PREV does not
-     use what NEW sets, we can insert NEW before PREV. */
-
-  prev = prev_active_insn (insn);
-  for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
-    if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
-	&& reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
-				    insn)
-	&& ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
-			    prev))
-      return 0;
-
-  return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
-}
-#endif /* !HAVE_cc0 */

gcc/timevar.def

@@ -51,12 +51,14 @@ DEFTIMEVAR (TV_CSE2                  , "CSE 2")
 DEFTIMEVAR (TV_BRANCH_PROB           , "branch prediction")
 DEFTIMEVAR (TV_FLOW                  , "flow analysis")
 DEFTIMEVAR (TV_COMBINE               , "combiner")
+DEFTIMEVAR (TV_IFCVT		     , "if-conversion")
 DEFTIMEVAR (TV_REGMOVE               , "regmove")
 DEFTIMEVAR (TV_SCHED                 , "scheduling")
 DEFTIMEVAR (TV_LOCAL_ALLOC           , "local alloc")
 DEFTIMEVAR (TV_GLOBAL_ALLOC          , "global alloc")
 DEFTIMEVAR (TV_RELOAD_CSE_REGS       , "reload CSE regs")
 DEFTIMEVAR (TV_FLOW2                 , "flow 2")
+DEFTIMEVAR (TV_IFCVT2		     , "if-conversion 2")
 DEFTIMEVAR (TV_PEEPHOLE2             , "peephole 2")
 DEFTIMEVAR (TV_SCHED2                , "schedulding 2")
 DEFTIMEVAR (TV_DBR_SCHED             , "delay branch sched")

gcc/toplev.c

@@ -264,11 +264,13 @@ enum dump_file_index
   DFI_bp,
   DFI_flow,
   DFI_combine,
+  DFI_ce,
   DFI_regmove,
   DFI_sched,
   DFI_lreg,
   DFI_greg,
   DFI_flow2,
+  DFI_ce2,
   DFI_peephole2,
   DFI_sched2,
   DFI_bbro,
@@ -281,7 +283,13 @@ enum dump_file_index
 };
 
 /* Describes all the dump files.  Should be kept in order of the
-   pass and in sync with dump_file_index above.  */
+   pass and in sync with dump_file_index above.
+
+   Remaining -d letters:
+
+	"       h      o q   u     "
+	"       H  K   OPQ  TUVWXYZ"
+*/
 
 struct dump_file_info dump_file[DFI_MAX] = 
 {
@@ -298,11 +306,13 @@ struct dump_file_info dump_file[DFI_MAX] =
   { "bp",	'b', 1, 0, 0 },
   { "flow",	'f', 1, 0, 0 },
   { "combine",	'c', 1, 0, 0 },
+  { "ce",	'C', 1, 0, 0 },
   { "regmove",	'N', 1, 0, 0 },
   { "sched",	'S', 1, 0, 0 },
   { "lreg",	'l', 1, 0, 0 },
   { "greg",	'g', 1, 0, 0 },
   { "flow2",	'w', 1, 0, 0 },
+  { "ce2",	'E', 1, 0, 0 },
   { "peephole2", 'z', 1, 0, 0 },
   { "sched2",	'R', 1, 0, 0 },
   { "bbro",	'B', 1, 0, 0 },
@@ -2814,12 +2824,23 @@ rest_of_compilation (decl)
     }
 
   timevar_push (TV_JUMP);
-  /* Try to identify useless null pointer tests and delete them.  */
-  if (flag_delete_null_pointer_checks)
+
+  if (optimize > 0)
     {
       find_basic_blocks (insns, max_reg_num (), rtl_dump_file);
       cleanup_cfg (insns);
-      delete_null_pointer_checks (insns);
+
+      /* ??? Run if-conversion before delete_null_pointer_checks,
+         since the later does not preserve the CFG.  This should
+	 be changed -- no since converting if's that are going to
+	 be deleted.  */
+      timevar_push (TV_IFCVT);
+      if_convert (0);
+      timevar_pop (TV_IFCVT);
+
+      /* Try to identify useless null pointer tests and delete them.  */
+      if (flag_delete_null_pointer_checks)
+	delete_null_pointer_checks (insns);
     }
 
   /* Jump optimization, and the removal of NULL pointer checks, may
@@ -2998,11 +3019,6 @@ rest_of_compilation (decl)
 	ggc_collect ();
     }
 
-  /* ??? Well, nearly.  If HAVE_conditional_arithmetic, jump_optimize
-     has put off all if-conversion until "after CSE".  If we put this
-     off any longer we may miss out doing if-conversion entirely.  */
-  cse_not_expected = 1;
-
   if (optimize > 0)
     {
       timevar_push (TV_CSE2);
@@ -3016,9 +3032,19 @@ rest_of_compilation (decl)
 	     max_reg_num so we must rerun reg_scan afterwards.
 	     ??? Rework to not call reg_scan so often.  */
 	  timevar_push (TV_JUMP);
+
 	  reg_scan (insns, max_reg_num (), 0);
 	  jump_optimize (insns, !JUMP_CROSS_JUMP,
 			 !JUMP_NOOP_MOVES, JUMP_AFTER_REGSCAN);
+
+	  timevar_push (TV_IFCVT);
+
+	  find_basic_blocks (insns, max_reg_num (), rtl_dump_file);
+	  cleanup_cfg (insns);
+	  if_convert (0);
+
+	  timevar_pop(TV_IFCVT);
+
 	  timevar_pop (TV_JUMP);
 	  
 	  reg_scan (insns, max_reg_num (), 0);
@@ -3050,6 +3076,8 @@ rest_of_compilation (decl)
 	ggc_collect ();
     }
 
+  cse_not_expected = 1;
+
   if (profile_arc_flag || flag_test_coverage || flag_branch_probabilities)
     {
       timevar_push (TV_BRANCH_PROB);
@@ -3110,10 +3138,6 @@ rest_of_compilation (decl)
   if (ggc_p)
     ggc_collect ();
 
-  /* The first life analysis pass has finished.  From now on we can not
-     generate any new pseudos.  */
-  no_new_pseudos = 1;
-
   /* If -opt, try combining insns through substitution.  */
 
   if (optimize > 0)
@@ -3134,6 +3158,20 @@ rest_of_compilation (decl)
 	  timevar_push (TV_JUMP);
 	  rebuild_jump_labels (insns);
 	  timevar_pop (TV_JUMP);
+
+	  timevar_push (TV_FLOW);
+	  find_basic_blocks (insns, max_reg_num (), rtl_dump_file);
+	  cleanup_cfg (insns);
+
+	  /* Blimey.  We've got to have the CFG up to date for the call to
+	     if_convert below.  However, the random deletion of blocks
+	     without updating life info can wind up with Wierd Stuff in
+	     global_live_at_end.  We then run sched1, which updates things
+	     properly, discovers the wierdness and aborts.  */
+	  update_life_info (NULL, UPDATE_LIFE_GLOBAL_RM_NOTES,
+			    PROP_DEATH_NOTES);
+
+	  timevar_pop (TV_FLOW);
 	}
 
       close_dump_file (DFI_combine, print_rtl_with_bb, insns);
@@ -3143,6 +3181,19 @@ rest_of_compilation (decl)
 	ggc_collect ();
     }
 
+  /* Rerun if-conversion, as combine may have simplified things enough to
+     now meet sequence length restrictions.  */
+  if (optimize > 0)
+    {
+      timevar_push (TV_IFCVT);
+      open_dump_file (DFI_ce, decl);
+
+      if_convert (1);
+
+      close_dump_file (DFI_ce, print_rtl_with_bb, insns);
+      timevar_pop (TV_IFCVT);
+    }
+
   /* Register allocation pre-pass, to reduce number of moves
      necessary for two-address machines.  */
   if (optimize > 0 && (flag_regmove || flag_expensive_optimizations))
@@ -3185,6 +3236,10 @@ rest_of_compilation (decl)
 
       if (ggc_p)
 	ggc_collect ();
+
+      /* Register lifetime information is up to date.  From now on
+	 we can not generate any new pseudos.  */
+      no_new_pseudos = 1;
     }
 #endif
 
@@ -3204,7 +3259,13 @@ rest_of_compilation (decl)
   /* We recomputed reg usage as part of updating the rest
      of life info during sched.  */
   if (! flag_schedule_insns)
-    recompute_reg_usage (insns, ! optimize_size);
+    {
+      recompute_reg_usage (insns, ! optimize_size);
+
+      /* Register lifetime information is up to date.  From now on
+	 we can not generate any new pseudos.  */
+      no_new_pseudos = 1;
+    }
   regclass (insns, max_reg_num (), rtl_dump_file);
   rebuild_label_notes_after_reload = local_alloc ();
 
@@ -3317,12 +3378,23 @@ rest_of_compilation (decl)
   close_dump_file (DFI_flow2, print_rtl_with_bb, insns);
   timevar_pop (TV_FLOW2);
 
+  if (optimize > 0)
+    {
+      timevar_push (TV_IFCVT2);
+      open_dump_file (DFI_ce2, decl);
+
+      if_convert (1);
+
+      close_dump_file (DFI_ce2, print_rtl_with_bb, insns);
+      timevar_pop (TV_IFCVT2);
+    }
+
 #ifdef HAVE_peephole2
   if (optimize > 0 && flag_peephole2)
     {
       timevar_push (TV_PEEPHOLE2);
-
       open_dump_file (DFI_peephole2, decl);
+
       peephole2_optimize (rtl_dump_file);
 
       close_dump_file (DFI_peephole2, print_rtl_with_bb, insns);
@@ -3387,6 +3459,8 @@ rest_of_compilation (decl)
       jump_optimize (insns, JUMP_CROSS_JUMP, JUMP_NOOP_MOVES, 
 		     !JUMP_AFTER_REGSCAN);
 
+      /* CFG no longer kept up to date.  */
+
       close_dump_file (DFI_jump2, print_rtl_with_bb, insns);
       timevar_pop (TV_JUMP);
     }