Joern Rennecke wrote:

Joern Rennecke wrote:

I've found that the most striking compilation time increase was for flex / parse.c, which is a bison parser. -Os compilation for i686-pc-linux-gnu X sh-elf --disable-checking went from 0.95 to 4.5 seconds.

Optimizing the REG_SET_EQ invocations gave a moderate win, down to 3.5 seconds.

Doing only one update_life_info_in_dirty_blocks before the crossjumping makes the compilation time go right back to 0.95 seconds. If that works, is another question... if there are any transformations that invalidate global_live_at_end, we'll have to make them update these regsets.

2006-01-05  J"orn Rennecke <[EMAIL PROTECTED]>

        * cfgcleanup.c: Reinstate patches for PR 20070
        * struct-equiv.c (struct_equiv_regs_eq_p): New function.
        (struct_equiv_init): Only call update_life_info_in_dirty_blocks
        in order to initialize regsets if both blocks are dirty.
        Make do sanity check of registers bening equal for STRUCT_EQUIV_FINAL.
        Add new parameter check_regs_eq.  Changed all callers.
        * basic-block.h (struct_equiv_init): Update prototype.

        * basic_block.h (STRUCT_EQUIV_SUSPEND_UPDATE): Define.
        * struct-equiv.c (struct_equiv_regs_eq_p): Don't call
        update_life_info_in_dirty_blocks if STRUCT_EQUIV_SUSPEND_UPDATE
        is set in info->mode.
        (struct_equiv_init): Likewise.  Also, add sanity check of
        global_live_at_end in that case.
        * cfgcleanup.c (try_optimize_cfg): Call
        update_life_info_in_dirty_blocks before start of loop.  Set
        STRUCT_EQUIV_SUSPEND_UPDATE in mode argument passed to
        try_crossjump_bb.

Index: cfgcleanup.c
===================================================================
/usr/bin/diff -p -d -F^( -u -L cfgcleanup.c     (revision 109329) -L 
cfgcleanup.c       (working copy) .svn/text-base/cfgcleanup.c.svn-base 
cfgcleanup.c
--- cfgcleanup.c        (revision 109329)
+++ cfgcleanup.c        (working copy)
@@ -60,9 +60,7 @@ Software Foundation, 51 Franklin Street,
 static bool first_pass;
 static bool try_crossjump_to_edge (int, edge, edge);
 static bool try_crossjump_bb (int, basic_block);
-static bool outgoing_edges_match (int, basic_block, basic_block);
-static int flow_find_cross_jump (int, basic_block, basic_block, rtx *, rtx *);
-static bool old_insns_match_p (int, rtx, rtx);
+static bool outgoing_edges_match (int *, struct equiv_info *);
 
 static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block);
 static void merge_blocks_move_successor_nojumps (basic_block, basic_block);
@@ -74,7 +72,6 @@ static bool mark_effect (rtx, bitmap);
 static void notice_new_block (basic_block);
 static void update_forwarder_flag (basic_block);
 static int mentions_nonequal_regs (rtx *, void *);
-static void merge_memattrs (rtx, rtx);
 
 /* Set flags for newly created block.  */
 
@@ -881,319 +878,6 @@ merge_blocks_move (edge e, basic_block b
   return NULL;
 }
 
-
-/* Removes the memory attributes of MEM expression
-   if they are not equal.  */
-
-void
-merge_memattrs (rtx x, rtx y)
-{
-  int i;
-  int j;
-  enum rtx_code code;
-  const char *fmt;
-
-  if (x == y)
-    return;
-  if (x == 0 || y == 0)
-    return;
-
-  code = GET_CODE (x);
-
-  if (code != GET_CODE (y))
-    return;
-
-  if (GET_MODE (x) != GET_MODE (y))
-    return;
-
-  if (code == MEM && MEM_ATTRS (x) != MEM_ATTRS (y))
-    {
-      if (! MEM_ATTRS (x))
-       MEM_ATTRS (y) = 0;
-      else if (! MEM_ATTRS (y))
-       MEM_ATTRS (x) = 0;
-      else 
-       {
-         rtx mem_size;
-
-         if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y))
-           {
-             set_mem_alias_set (x, 0);
-             set_mem_alias_set (y, 0);
-           }
-         
-         if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y)))
-           {
-             set_mem_expr (x, 0);
-             set_mem_expr (y, 0);
-             set_mem_offset (x, 0);
-             set_mem_offset (y, 0);
-           }
-         else if (MEM_OFFSET (x) != MEM_OFFSET (y))
-           {
-             set_mem_offset (x, 0);
-             set_mem_offset (y, 0);
-           }
-        
-         if (!MEM_SIZE (x))
-           mem_size = NULL_RTX;
-         else if (!MEM_SIZE (y))
-           mem_size = NULL_RTX;
-         else
-           mem_size = GEN_INT (MAX (INTVAL (MEM_SIZE (x)),
-                                    INTVAL (MEM_SIZE (y))));
-         set_mem_size (x, mem_size);
-         set_mem_size (y, mem_size);
-
-         set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y)));
-         set_mem_align (y, MEM_ALIGN (x));
-       }
-    }
-  
-  fmt = GET_RTX_FORMAT (code);
-  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
-    {
-      switch (fmt[i])
-       {
-       case 'E':
-         /* Two vectors must have the same length.  */
-         if (XVECLEN (x, i) != XVECLEN (y, i))
-           return;
-
-         for (j = 0; j < XVECLEN (x, i); j++)
-           merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j));
-
-         break;
-
-       case 'e':
-         merge_memattrs (XEXP (x, i), XEXP (y, i));
-       }
-    }
-  return;
-}
-
-
-/* Return true if I1 and I2 are equivalent and thus can be crossjumped.  */
-
-static bool
-old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx i1, rtx i2)
-{
-  rtx p1, p2;
-
-  /* Verify that I1 and I2 are equivalent.  */
-  if (GET_CODE (i1) != GET_CODE (i2))
-    return false;
-
-  p1 = PATTERN (i1);
-  p2 = PATTERN (i2);
-
-  if (GET_CODE (p1) != GET_CODE (p2))
-    return false;
-
-  /* If this is a CALL_INSN, compare register usage information.
-     If we don't check this on stack register machines, the two
-     CALL_INSNs might be merged leaving reg-stack.c with mismatching
-     numbers of stack registers in the same basic block.
-     If we don't check this on machines with delay slots, a delay slot may
-     be filled that clobbers a parameter expected by the subroutine.
-
-     ??? We take the simple route for now and assume that if they're
-     equal, they were constructed identically.  */
-
-  if (CALL_P (i1)
-      && (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
-                       CALL_INSN_FUNCTION_USAGE (i2))
-         || SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2)))
-    return false;
-
-#ifdef STACK_REGS
-  /* If cross_jump_death_matters is not 0, the insn's mode
-     indicates whether or not the insn contains any stack-like
-     regs.  */
-
-  if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1))
-    {
-      /* If register stack conversion has already been done, then
-         death notes must also be compared before it is certain that
-         the two instruction streams match.  */
-
-      rtx note;
-      HARD_REG_SET i1_regset, i2_regset;
-
-      CLEAR_HARD_REG_SET (i1_regset);
-      CLEAR_HARD_REG_SET (i2_regset);
-
-      for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
-       if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0)))
-         SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
-
-      for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
-       if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0)))
-         SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
-
-      GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
-
-      return false;
-
-    done:
-      ;
-    }
-#endif
-
-  if (reload_completed
-      ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2))
-    return true;
-
-  /* Do not do EQUIV substitution after reload.  First, we're undoing the
-     work of reload_cse.  Second, we may be undoing the work of the post-
-     reload splitting pass.  */
-  /* ??? Possibly add a new phase switch variable that can be used by
-     targets to disallow the troublesome insns after splitting.  */
-  if (!reload_completed)
-    {
-      /* The following code helps take care of G++ cleanups.  */
-      rtx equiv1 = find_reg_equal_equiv_note (i1);
-      rtx equiv2 = find_reg_equal_equiv_note (i2);
-
-      if (equiv1 && equiv2
-         /* If the equivalences are not to a constant, they may
-            reference pseudos that no longer exist, so we can't
-            use them.  */
-         && (! reload_completed
-             || (CONSTANT_P (XEXP (equiv1, 0))
-                 && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))))
-       {
-         rtx s1 = single_set (i1);
-         rtx s2 = single_set (i2);
-         if (s1 != 0 && s2 != 0
-             && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
-           {
-             validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
-             validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
-             if (! rtx_renumbered_equal_p (p1, p2))
-               cancel_changes (0);
-             else if (apply_change_group ())
-               return true;
-           }
-       }
-    }
-
-  return false;
-}
-
-/* Look through the insns at the end of BB1 and BB2 and find the longest
-   sequence that are equivalent.  Store the first insns for that sequence
-   in *F1 and *F2 and return the sequence length.
-
-   To simplify callers of this function, if the blocks match exactly,
-   store the head of the blocks in *F1 and *F2.  */
-
-static int
-flow_find_cross_jump (int mode ATTRIBUTE_UNUSED, basic_block bb1,
-                     basic_block bb2, rtx *f1, rtx *f2)
-{
-  rtx i1, i2, last1, last2, afterlast1, afterlast2;
-  int ninsns = 0;
-
-  /* Skip simple jumps at the end of the blocks.  Complex jumps still
-     need to be compared for equivalence, which we'll do below.  */
-
-  i1 = BB_END (bb1);
-  last1 = afterlast1 = last2 = afterlast2 = NULL_RTX;
-  if (onlyjump_p (i1)
-      || (returnjump_p (i1) && !side_effects_p (PATTERN (i1))))
-    {
-      last1 = i1;
-      i1 = PREV_INSN (i1);
-    }
-
-  i2 = BB_END (bb2);
-  if (onlyjump_p (i2)
-      || (returnjump_p (i2) && !side_effects_p (PATTERN (i2))))
-    {
-      last2 = i2;
-      /* Count everything except for unconditional jump as insn.  */
-      if (!simplejump_p (i2) && !returnjump_p (i2) && last1)
-       ninsns++;
-      i2 = PREV_INSN (i2);
-    }
-
-  while (true)
-    {
-      /* Ignore notes.  */
-      while (!INSN_P (i1) && i1 != BB_HEAD (bb1))
-       i1 = PREV_INSN (i1);
-
-      while (!INSN_P (i2) && i2 != BB_HEAD (bb2))
-       i2 = PREV_INSN (i2);
-
-      if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2))
-       break;
-
-      if (!old_insns_match_p (mode, i1, i2))
-       break;
-
-      merge_memattrs (i1, i2);
-
-      /* Don't begin a cross-jump with a NOTE insn.  */
-      if (INSN_P (i1))
-       {
-         /* If the merged insns have different REG_EQUAL notes, then
-            remove them.  */
-         rtx equiv1 = find_reg_equal_equiv_note (i1);
-         rtx equiv2 = find_reg_equal_equiv_note (i2);
-
-         if (equiv1 && !equiv2)
-           remove_note (i1, equiv1);
-         else if (!equiv1 && equiv2)
-           remove_note (i2, equiv2);
-         else if (equiv1 && equiv2
-                  && !rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
-           {
-             remove_note (i1, equiv1);
-             remove_note (i2, equiv2);
-           }
-
-         afterlast1 = last1, afterlast2 = last2;
-         last1 = i1, last2 = i2;
-         ninsns++;
-       }
-
-      i1 = PREV_INSN (i1);
-      i2 = PREV_INSN (i2);
-    }
-
-#ifdef HAVE_cc0
-  /* Don't allow the insn after a compare to be shared by
-     cross-jumping unless the compare is also shared.  */
-  if (ninsns && reg_mentioned_p (cc0_rtx, last1) && ! sets_cc0_p (last1))
-    last1 = afterlast1, last2 = afterlast2, ninsns--;
-#endif
-
-  /* Include preceding notes and labels in the cross-jump.  One,
-     this may bring us to the head of the blocks as requested above.
-     Two, it keeps line number notes as matched as may be.  */
-  if (ninsns)
-    {
-      while (last1 != BB_HEAD (bb1) && !INSN_P (PREV_INSN (last1)))
-       last1 = PREV_INSN (last1);
-
-      if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1)))
-       last1 = PREV_INSN (last1);
-
-      while (last2 != BB_HEAD (bb2) && !INSN_P (PREV_INSN (last2)))
-       last2 = PREV_INSN (last2);
-
-      if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2)))
-       last2 = PREV_INSN (last2);
-
-      *f1 = last1;
-      *f2 = last2;
-    }
-
-  return ninsns;
-}
-
 /* Return true iff the condbranches at the end of BB1 and BB2 match.  */
 bool
 condjump_equiv_p (struct equiv_info *info, bool call_init)
@@ -1252,8 +936,8 @@ condjump_equiv_p (struct equiv_info *inf
   if (code2 == UNKNOWN)
     return false;
 
-  if (call_init && !struct_equiv_init (STRUCT_EQUIV_START | info->mode, info))
-    gcc_unreachable ();
+  if (call_init)
+    struct_equiv_init (STRUCT_EQUIV_START | info->mode, info, false);
   /* Make the sources of the pc sets unreadable so that when we call
      insns_match_p it won't process them.
      The death_notes_match_p from insns_match_p won't see the local registers
@@ -1322,15 +1006,20 @@ condjump_equiv_p (struct equiv_info *inf
   return match;
 }
 
-/* Return true iff outgoing edges of BB1 and BB2 match, together with
-   the branch instruction.  This means that if we commonize the control
-   flow before end of the basic block, the semantic remains unchanged.
+/* Return true iff outgoing edges of INFO->y_block and INFO->x_block match,
+   together with the branch instruction.  This means that if we commonize the
+   control flow before end of the basic block, the semantic remains unchanged.
+   If we need to compare jumps, we set STRUCT_EQUIV_MATCH_JUMPS in *MODE,
+   and pass *MODE to struct_equiv_init or assign it to INFO->mode, as
+   appropriate.
 
    We may assume that there exists one edge with a common destination.  */
 
 static bool
-outgoing_edges_match (int mode, basic_block bb1, basic_block bb2)
+outgoing_edges_match (int *mode, struct equiv_info *info)
 {
+  basic_block bb1 = info->y_block;
+  basic_block bb2 = info->x_block;
   int nehedges1 = 0, nehedges2 = 0;
   edge fallthru1 = 0, fallthru2 = 0;
   edge e1, e2;
@@ -1346,114 +1035,19 @@ outgoing_edges_match (int mode, basic_bl
                & (EDGE_COMPLEX | EDGE_FAKE)) == 0
            && (!JUMP_P (BB_END (bb2)) || simplejump_p (BB_END (bb2))));
 
+  *mode |= STRUCT_EQUIV_MATCH_JUMPS;
   /* Match conditional jumps - this may get tricky when fallthru and branch
      edges are crossed.  */
   if (EDGE_COUNT (bb1->succs) == 2
       && any_condjump_p (BB_END (bb1))
       && onlyjump_p (BB_END (bb1)))
     {
-      edge b1, f1, b2, f2;
-      bool reverse, match;
-      rtx set1, set2, cond1, cond2;
-      enum rtx_code code1, code2;
-
       if (EDGE_COUNT (bb2->succs) != 2
          || !any_condjump_p (BB_END (bb2))
          || !onlyjump_p (BB_END (bb2)))
        return false;
-
-      b1 = BRANCH_EDGE (bb1);
-      b2 = BRANCH_EDGE (bb2);
-      f1 = FALLTHRU_EDGE (bb1);
-      f2 = FALLTHRU_EDGE (bb2);
-
-      /* Get around possible forwarders on fallthru edges.  Other cases
-         should be optimized out already.  */
-      if (FORWARDER_BLOCK_P (f1->dest))
-       f1 = single_succ_edge (f1->dest);
-
-      if (FORWARDER_BLOCK_P (f2->dest))
-       f2 = single_succ_edge (f2->dest);
-
-      /* To simplify use of this function, return false if there are
-        unneeded forwarder blocks.  These will get eliminated later
-        during cleanup_cfg.  */
-      if (FORWARDER_BLOCK_P (f1->dest)
-         || FORWARDER_BLOCK_P (f2->dest)
-         || FORWARDER_BLOCK_P (b1->dest)
-         || FORWARDER_BLOCK_P (b2->dest))
-       return false;
-
-      if (f1->dest == f2->dest && b1->dest == b2->dest)
-       reverse = false;
-      else if (f1->dest == b2->dest && b1->dest == f2->dest)
-       reverse = true;
-      else
-       return false;
-
-      set1 = pc_set (BB_END (bb1));
-      set2 = pc_set (BB_END (bb2));
-      if ((XEXP (SET_SRC (set1), 1) == pc_rtx)
-         != (XEXP (SET_SRC (set2), 1) == pc_rtx))
-       reverse = !reverse;
-
-      cond1 = XEXP (SET_SRC (set1), 0);
-      cond2 = XEXP (SET_SRC (set2), 0);
-      code1 = GET_CODE (cond1);
-      if (reverse)
-       code2 = reversed_comparison_code (cond2, BB_END (bb2));
-      else
-       code2 = GET_CODE (cond2);
-
-      if (code2 == UNKNOWN)
-       return false;
-
-      /* Verify codes and operands match.  */
-      match = ((code1 == code2
-               && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0))
-               && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1)))
-              || (code1 == swap_condition (code2)
-                  && rtx_renumbered_equal_p (XEXP (cond1, 1),
-                                             XEXP (cond2, 0))
-                  && rtx_renumbered_equal_p (XEXP (cond1, 0),
-                                             XEXP (cond2, 1))));
-
-      /* If we return true, we will join the blocks.  Which means that
-        we will only have one branch prediction bit to work with.  Thus
-        we require the existing branches to have probabilities that are
-        roughly similar.  */
-      if (match
-         && !optimize_size
-         && maybe_hot_bb_p (bb1)
-         && maybe_hot_bb_p (bb2))
-       {
-         int prob2;
-
-         if (b1->dest == b2->dest)
-           prob2 = b2->probability;
-         else
-           /* Do not use f2 probability as f2 may be forwarded.  */
-           prob2 = REG_BR_PROB_BASE - b2->probability;
-
-         /* Fail if the difference in probabilities is greater than 50%.
-            This rules out two well-predicted branches with opposite
-            outcomes.  */
-         if (abs (b1->probability - prob2) > REG_BR_PROB_BASE / 2)
-           {
-             if (dump_file)
-               fprintf (dump_file,
-                        "Outcomes of branch in bb %i and %i differ too much 
(%i %i)\n",
-                        bb1->index, bb2->index, b1->probability, prob2);
-
-             return false;
-           }
-       }
-
-      if (dump_file && match)
-       fprintf (dump_file, "Conditionals in bb %i and %i match.\n",
-                bb1->index, bb2->index);
-
-      return match;
+      info->mode = *mode;
+      return condjump_equiv_p (info, true);
     }
 
   /* Generic case - we are seeing a computed jump, table jump or trapping
@@ -1501,31 +1095,22 @@ outgoing_edges_match (int mode, basic_bl
                      identical = false;
                }
 
-             if (identical)
+             if (identical
+                 && struct_equiv_init (STRUCT_EQUIV_START | *mode, info, true))
                {
-                 replace_label_data rr;
                  bool match;
 
-                 /* Temporarily replace references to LABEL1 with LABEL2
+                 /* Indicate that LABEL1 is to be replaced with LABEL2
                     in BB1->END so that we could compare the instructions.  */
-                 rr.r1 = label1;
-                 rr.r2 = label2;
-                 rr.update_label_nuses = false;
-                 for_each_rtx (&BB_END (bb1), replace_label, &rr);
+                 info->y_label = label1;
+                 info->x_label = label2;
 
-                 match = old_insns_match_p (mode, BB_END (bb1), BB_END (bb2));
+                 match = insns_match_p (BB_END (bb1), BB_END (bb2), info);
                  if (dump_file && match)
                    fprintf (dump_file,
                             "Tablejumps in bb %i and %i match.\n",
                             bb1->index, bb2->index);
 
-                 /* Set the original label in BB1->END because when deleting
-                    a block whose end is a tablejump, the tablejump referenced
-                    from the instruction is deleted too.  */
-                 rr.r1 = label2;
-                 rr.r2 = label1;
-                 for_each_rtx (&BB_END (bb1), replace_label, &rr);
-
                  return match;
                }
            }
@@ -1535,7 +1120,10 @@ outgoing_edges_match (int mode, basic_bl
 
   /* First ensure that the instructions match.  There may be many outgoing
      edges so this test is generally cheaper.  */
-  if (!old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)))
+  /* FIXME: the regset compare might be costly.  We should try to get a cheap
+     and reasonably effective test first.  */
+  if (!struct_equiv_init (STRUCT_EQUIV_START | *mode, info, true)
+      || !insns_match_p (BB_END (bb1), BB_END (bb2), info))
     return false;
 
   /* Search the outgoing edges, ensure that the counts do match, find possible
@@ -1601,22 +1189,21 @@ outgoing_edges_match (int mode, basic_bl
 static bool
 try_crossjump_to_edge (int mode, edge e1, edge e2)
 {
-  int nmatch;
+  int nmatch, i;
   basic_block src1 = e1->src, src2 = e2->src;
   basic_block redirect_to, redirect_from, to_remove;
-  rtx newpos1, newpos2;
   edge s;
   edge_iterator ei;
-
-  newpos1 = newpos2 = NULL_RTX;
+  struct equiv_info info;
+  rtx x_active, y_active;
 
   /* If we have partitioned hot/cold basic blocks, it is a bad idea
-     to try this optimization. 
+     to try this optimization.
 
      Basic block partitioning may result in some jumps that appear to
-     be optimizable (or blocks that appear to be mergeable), but which really 
-     must be left untouched (they are required to make it safely across 
-     partition boundaries).  See the comments at the top of 
+     be optimizable (or blocks that appear to be mergeable), but which really
+     must be left untouched (they are required to make it safely across
+     partition boundaries).  See the comments at the top of
      bb-reorder.c:partition_hot_cold_basic_blocks for complete details.  */
 
   if (flag_reorder_blocks_and_partition && no_new_pseudos)
@@ -1655,19 +1242,66 @@ try_crossjump_to_edge (int mode, edge e1
     return false;
 
   /* Look for the common insn sequence, part the first ...  */
-  if (!outgoing_edges_match (mode, src1, src2))
+  info.x_block = src2;
+  info.y_block = src1;
+  if (!outgoing_edges_match (&mode, &info))
     return false;
 
   /* ... and part the second.  */
-  nmatch = flow_find_cross_jump (mode, src1, src2, &newpos1, &newpos2);
+  info.input_cost = optimize_size ? COSTS_N_INSNS (1) : -1;
+  nmatch = struct_equiv_block_eq (STRUCT_EQUIV_START | mode, &info);
 
   /* Don't proceed with the crossjump unless we found a sufficient number
      of matching instructions or the 'from' block was totally matched
      (such that its predecessors will hopefully be redirected and the
      block removed).  */
-  if ((nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
-      && (newpos1 != BB_HEAD (src1)))
+  if (!nmatch)
     return false;
+  if ((nmatch -info.cur.input_count < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
+      && (info.cur.y_start != BB_HEAD (src1)))
+    return false;
+  while (info.need_rerun)
+    {
+      nmatch = struct_equiv_block_eq (STRUCT_EQUIV_RERUN | mode, &info);
+      if (!nmatch)
+       return false;
+      if ((nmatch -info.cur.input_count < PARAM_VALUE 
(PARAM_MIN_CROSSJUMP_INSNS))
+          && (info.cur.y_start != BB_HEAD (src1)))
+       return false;
+    }
+  nmatch = struct_equiv_block_eq (STRUCT_EQUIV_FINAL | mode, &info);
+  if ((nmatch -info.cur.input_count < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
+      && (info.cur.y_start != BB_HEAD (src1)))
+    return false;
+
+  /* Skip possible basic block header.  */
+  x_active = info.cur.x_start;
+  if (LABEL_P (x_active))
+    x_active = NEXT_INSN (x_active);
+  if (NOTE_P (x_active))
+    x_active = NEXT_INSN (x_active);
+
+  y_active = info.cur.y_start;
+  if (LABEL_P (y_active))
+    y_active = NEXT_INSN (y_active);
+  if (NOTE_P (y_active))
+    y_active = NEXT_INSN (y_active);
+
+  /* In order for this code to become active, either we have to be called
+     before reload, or struct_equiv_block_eq needs to add register scavenging
+     code to allocate input_reg after reload.  */
+  if (info.input_reg)
+    {
+      emit_insn_before (gen_move_insn (info.input_reg, info.x_input),
+                       x_active);
+      emit_insn_before (gen_move_insn (info.input_reg, info.y_input),
+                       y_active);
+    }
+
+  for (i = 0; i < info.cur.local_count; i++)
+    if (info.local_rvalue[i])
+      emit_insn_before (gen_move_insn (info.x_local[i], info.y_local[i]),
+                       y_active);
 
   /* Here we know that the insns in the end of SRC1 which are common with SRC2
      will be deleted.
@@ -1703,30 +1337,36 @@ try_crossjump_to_edge (int mode, edge e1
   /* Avoid splitting if possible.  We must always split when SRC2 has
      EH predecessor edges, or we may end up with basic blocks with both
      normal and EH predecessor edges.  */
-  if (newpos2 == BB_HEAD (src2)
+  if (info.cur.x_start == BB_HEAD (src2)
       && !(EDGE_PRED (src2, 0)->flags & EDGE_EH))
     redirect_to = src2;
   else
     {
-      if (newpos2 == BB_HEAD (src2))
+      if (info.cur.x_start == BB_HEAD (src2))
        {
          /* Skip possible basic block header.  */
-         if (LABEL_P (newpos2))
-           newpos2 = NEXT_INSN (newpos2);
-         if (NOTE_P (newpos2))
-           newpos2 = NEXT_INSN (newpos2);
+         if (LABEL_P (info.cur.x_start))
+           info.cur.x_start = NEXT_INSN (info.cur.x_start);
+         if (NOTE_P (info.cur.x_start))
+           info.cur.x_start = NEXT_INSN (info.cur.x_start);
        }
 
       if (dump_file)
        fprintf (dump_file, "Splitting bb %i before %i insns\n",
                 src2->index, nmatch);
-      redirect_to = split_block (src2, PREV_INSN (newpos2))->dest;
+      redirect_to = split_block (src2, PREV_INSN (info.cur.x_start))->dest;
+      COPY_REG_SET (info.y_block->il.rtl->global_live_at_end,
+                   info.x_block->il.rtl->global_live_at_end);
     }
 
   if (dump_file)
-    fprintf (dump_file,
-            "Cross jumping from bb %i to bb %i; %i common insns\n",
-            src1->index, src2->index, nmatch);
+    {
+      fprintf (dump_file, "Cross jumping from bb %i to bb %i; %i common insns",
+              src1->index, src2->index, nmatch);
+      if (info.cur.local_count)
+       fprintf (dump_file, ", %i local registers", info.cur.local_count);
+       fprintf (dump_file, "\n");
+    }
 
   redirect_to->count += src1->count;
   redirect_to->frequency += src1->frequency;
@@ -1790,14 +1430,7 @@ try_crossjump_to_edge (int mode, edge e1
 
   /* Edit SRC1 to go to REDIRECT_TO at NEWPOS1.  */
 
-  /* Skip possible basic block header.  */
-  if (LABEL_P (newpos1))
-    newpos1 = NEXT_INSN (newpos1);
-
-  if (NOTE_P (newpos1))
-    newpos1 = NEXT_INSN (newpos1);
-
-  redirect_from = split_block (src1, PREV_INSN (newpos1))->src;
+  redirect_from = split_block (src1, PREV_INSN (y_active))->src;
   to_remove = single_succ (redirect_from);
 
   redirect_edge_and_branch_force (single_succ_edge (redirect_from), 
redirect_to);
@@ -1969,6 +1602,11 @@ try_optimize_cfg (int mode)
 
   if (! targetm.cannot_modify_jumps_p ())
     {
+      if (mode & CLEANUP_CROSSJUMP)
+       update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
+                                         (PROP_DEATH_NOTES
+                                          | ((mode & CLEANUP_POST_REGSTACK)
+                                             ? PROP_POST_REGSTACK : 0)));
       first_pass = true;
       /* Attempt to merge blocks as made possible by edge removal.  If
         a block has only one successor, and the successor has only
@@ -2124,7 +1762,7 @@ try_optimize_cfg (int mode)
 
              /* Look for shared code between blocks.  */
              if ((mode & CLEANUP_CROSSJUMP)
-                 && try_crossjump_bb (mode, b))
+                 && try_crossjump_bb (mode | STRUCT_EQUIV_SUSPEND_UPDATES, b))
                changed_here = true;
 
              /* Don't get confused by the index shift caused by
@@ -2136,7 +1774,8 @@ try_optimize_cfg (int mode)
            }
 
          if ((mode & CLEANUP_CROSSJUMP)
-             && try_crossjump_bb (mode, EXIT_BLOCK_PTR))
+             && try_crossjump_bb (mode | STRUCT_EQUIV_SUSPEND_UPDATES,
+                                  EXIT_BLOCK_PTR))
            changed = true;
 
 #ifdef ENABLE_CHECKING
Index: basic-block.h
===================================================================
/usr/bin/diff -p -d -F^( -u -L basic-block.h    (revision 109329) -L 
basic-block.h      (working copy) .svn/text-base/basic-block.h.svn-base 
basic-block.h
--- basic-block.h       (revision 109329)
+++ basic-block.h       (working copy)
@@ -850,6 +850,8 @@ enum update_life_extent
                                             to match only full blocks  */
 #define STRUCT_EQUIV_MATCH_JUMPS 8192  /* Also include the jumps at the end of 
the block in the comparison.  */
 
+#define STRUCT_EQUIV_SUSPEND_UPDATES 16384 /* Assume global_live_at_end is 
up-to-date even if the block isn't.  */
+
 extern void life_analysis (FILE *, int);
 extern int update_life_info (sbitmap, enum update_life_extent, int);
 extern int update_life_info_in_dirty_blocks (enum update_life_extent, int);
@@ -1169,7 +1171,7 @@ struct equiv_info
 
 extern bool insns_match_p (rtx, rtx, struct equiv_info *);
 extern int struct_equiv_block_eq (int, struct equiv_info *);
-extern bool struct_equiv_init (int, struct equiv_info *);
+extern bool struct_equiv_init (int, struct equiv_info *, bool);
 extern bool rtx_equiv_p (rtx *, rtx, int, struct equiv_info *);
 
 /* In cfgrtl.c */
Index: struct-equiv.c
===================================================================
/usr/bin/diff -p -d -F^( -u -L struct-equiv.c   (revision 109329) -L 
struct-equiv.c     (working copy) .svn/text-base/struct-equiv.c.svn-base 
struct-equiv.c
--- struct-equiv.c      (revision 109329)
+++ struct-equiv.c      (working copy)
@@ -987,38 +987,56 @@ insns_match_p (rtx i1, rtx i2, struct eq
   return false;
 }
 
-/* Set up mode and register information in INFO.  Return true for success.  */
-bool
-struct_equiv_init (int mode, struct equiv_info *info)
+static bool
+struct_equiv_regs_eq_p (struct equiv_info *info)
 {
-  if ((info->x_block->flags | info->y_block->flags) & BB_DIRTY)
+  if (!(info->mode & STRUCT_EQUIV_SUSPEND_UPDATES)
+      && ((info->x_block->flags | info->y_block->flags) & BB_DIRTY))
     update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
                                      (PROP_DEATH_NOTES
-                                      | ((mode & CLEANUP_POST_REGSTACK)
+                                      | ((info->mode & CLEANUP_POST_REGSTACK)
                                          ? PROP_POST_REGSTACK : 0)));
-  if (!REG_SET_EQUAL_P (info->x_block->il.rtl->global_live_at_end,
-                       info->y_block->il.rtl->global_live_at_end))
-    {
 #ifdef STACK_REGS
-      unsigned rn;
+  if (info->mode & CLEANUP_POST_REGSTACK)
+    {
+      unsigned regnum;
+      bitmap_iterator rsi;
 
-      if (!(mode & CLEANUP_POST_REGSTACK))
-       return false;
-      /* After reg-stack.  Remove bogus live info about stack regs.  N.B.
-        these regs are not necessarily all dead - we swap random bogosity
-        against constant bogosity.  However, clearing these bits at
-        least makes the regsets comparable.  */
-      for (rn = FIRST_STACK_REG; rn <= LAST_STACK_REG; rn++)
+      EXECUTE_IF_AND_IN_BITMAP (info->x_block->il.rtl->global_live_at_end,
+                               info->y_block->il.rtl->global_live_at_end,
+                               0, regnum, rsi)
        {
-         CLEAR_REGNO_REG_SET (info->x_block->il.rtl->global_live_at_end, rn);
-         CLEAR_REGNO_REG_SET (info->y_block->il.rtl->global_live_at_end, rn);
+         if (regnum < FIRST_STACK_REG || regnum > LAST_STACK_REG)
+           return false;
        }
-      if (!REG_SET_EQUAL_P (info->x_block->il.rtl->global_live_at_end,
-                           info->y_block->il.rtl->global_live_at_end))
+      return true;
+    }
 #endif
+  return (REG_SET_EQUAL_P (info->x_block->il.rtl->global_live_at_end,
+                          info->y_block->il.rtl->global_live_at_end));
+}
+
+/* Set up mode and register information in INFO.  Return true for success.
+   Nonzero CHECK_REGS_EQ indicates that we might be called with blocks that
+   have non-matching successor sets, and thus need to check their live_at_end
+   regsets for match in the first pass.  */
+bool
+struct_equiv_init (int mode, struct equiv_info *info, bool check_regs_eq)
+{
+  if (!(info->mode & STRUCT_EQUIV_SUSPEND_UPDATES)
+      && ((info->x_block->flags & info->y_block->flags) & BB_DIRTY))
+    update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
+                                     (PROP_DEATH_NOTES
+                                      | ((mode & CLEANUP_POST_REGSTACK)
+                                         ? PROP_POST_REGSTACK : 0)));
+  info->mode = mode;
+  if (check_regs_eq && (mode & STRUCT_EQUIV_START))
+    {
+      if (!struct_equiv_regs_eq_p (info))
        return false;
     }
-  info->mode = mode;
+  else if (mode & (STRUCT_EQUIV_FINAL | STRUCT_EQUIV_SUSPEND_UPDATES))
+    gcc_assert (struct_equiv_regs_eq_p (info));
   if (mode & STRUCT_EQUIV_START)
     {
       info->x_input = info->y_input = info->input_reg = NULL_RTX;
@@ -1036,7 +1054,10 @@ struct_equiv_init (int mode, struct equi
   info->common_live = ALLOC_REG_SET (&reg_obstack);
   info->x_local_live = ALLOC_REG_SET (&reg_obstack);
   info->y_local_live = ALLOC_REG_SET (&reg_obstack);
-  COPY_REG_SET (info->common_live, info->x_block->il.rtl->global_live_at_end);
+  COPY_REG_SET (info->common_live,
+               ((info->x_block->flags & BB_DIRTY
+                 ? info->y_block : info->x_block)
+                ->il.rtl->global_live_at_end));
   struct_equiv_make_checkpoint (&info->best_match, info);
   return true;
 }
@@ -1100,8 +1121,7 @@ struct_equiv_block_eq (int mode, struct 
       x_stop = info->cur.x_start;
       y_stop = info->cur.y_start;
     }
-  if (!struct_equiv_init (mode, info))
-    gcc_unreachable ();
+  struct_equiv_init (mode, info, false);
 
   /* Skip simple jumps at the end of the blocks.  Complex jumps still
      need to be compared for equivalence, which we'll do below.  */

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