Imported Upstream version 4.7.3

[platform/upstream/gcc48.git] / gcc / cfgcleanup.c

diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index b59cf7b..6ff1614 100644 (file)
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -1487,6 +1487,8 @@ outgoing_edges_match (int mode, basic_block bb1, basic_block bb2)
   edge fallthru1 = 0, fallthru2 = 0;
   edge e1, e2;
   edge_iterator ei;
+  rtx last1, last2;
+  bool nonfakeedges;
 
   /* If we performed shrink-wrapping, edges to the EXIT_BLOCK_PTR can
      only be distinguished for JUMP_INSNs.  The two paths may differ in
@@ -1695,9 +1697,15 @@ outgoing_edges_match (int mode, basic_block bb1, basic_block bb2)
        }
     }
 
+  last1 = BB_END (bb1);
+  last2 = BB_END (bb2);
+  if (DEBUG_INSN_P (last1))
+    last1 = prev_nondebug_insn (last1);
+  if (DEBUG_INSN_P (last2))
+    last2 = prev_nondebug_insn (last2);
   /* 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)) != dir_both)
+  if (old_insns_match_p (mode, last1, last2) != dir_both)
     return false;
 
   /* Search the outgoing edges, ensure that the counts do match, find possible
@@ -1706,10 +1714,14 @@ outgoing_edges_match (int mode, basic_block bb1, basic_block bb2)
   if (EDGE_COUNT (bb1->succs) != EDGE_COUNT (bb2->succs))
     return false;
 
+  nonfakeedges = false;
   FOR_EACH_EDGE (e1, ei, bb1->succs)
     {
       e2 = EDGE_SUCC (bb2, ei.index);
 
+      if ((e1->flags & EDGE_FAKE) == 0)
+       nonfakeedges = true;
+
       if (e1->flags & EDGE_EH)
        nehedges1++;
 
@@ -1727,6 +1739,18 @@ outgoing_edges_match (int mode, basic_block bb1, basic_block bb2)
       || (fallthru1 != 0) != (fallthru2 != 0))
     return false;
 
+  /* If !ACCUMULATE_OUTGOING_ARGS, bb1 (and bb2) have no successors
+     and the last real insn doesn't have REG_ARGS_SIZE note, don't
+     attempt to optimize, as the two basic blocks might have different
+     REG_ARGS_SIZE depths.  For noreturn calls and unconditional
+     traps there should be REG_ARG_SIZE notes, they could be missing
+     for __builtin_unreachable () uses though.  */
+  if (!nonfakeedges
+      && !ACCUMULATE_OUTGOING_ARGS
+      && (!INSN_P (last1)
+          || !find_reg_note (last1, REG_ARGS_SIZE, NULL)))
+    return false;
+
   /* fallthru edges must be forwarded to the same destination.  */
   if (fallthru1)
     {