flow.c (init_propagate_block_info): Watch out for conditional branch to next instruction, and thus one outgoing edge.

        * flow.c (init_propagate_block_info): Watch out for conditional
        branch to next instruction, and thus one outgoing edge.

From-SVN: r33775

2 files changed, 24 insertions, 6 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 81867aa..3318d80 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2000-05-08  Richard Henderson  <rth@cygnus.com>
+
+	* flow.c (init_propagate_block_info): Watch out for conditional
+	branch to next instruction, and thus one outgoing edge.
+
 2000-05-08  Nick Clifton  <nickc@cygnus.com>
 
 	* config/i386/i386.h (ELIMINABLE_REGS): Fix comment.
diff --git a/gcc/flow.c b/gcc/flow.c
index 5e05b02..c978ff1 100644
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -3573,16 +3573,29 @@ init_propagate_block_info (bb, live, local_set, flags)
       int i;
 
       /* Identify the successor blocks.  */
-      bb_false = bb->succ->succ_next->dest;
       bb_true = bb->succ->dest;
-      if (bb->succ->flags & EDGE_FALLTHRU)
+      if (bb->succ->succ_next != NULL)
 	{
-	  basic_block t = bb_false;
+          bb_false = bb->succ->succ_next->dest;
+
+	  if (bb->succ->flags & EDGE_FALLTHRU)
+	    {
+	      basic_block t = bb_false;
+	      bb_false = bb_true;
+	      bb_true = t;
+	    }
+	  else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
+	    abort ();
+	}
+      else
+	{
+	  /* This can happen with a conditional jump to the next insn.  */
+	  if (JUMP_LABEL (bb->end) != bb_true->head)
+	    abort ();
+
+	  /* Simplest way to do nothing.  */
 	  bb_false = bb_true;
-	  bb_true = t;
 	}
-      else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
-	abort ();
      
       /* Extract the condition from the branch.  */
       cond_true = XEXP (SET_SRC (PATTERN (bb->end)), 0);