1 files changed, 48 insertions, 7 deletions

diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 3c877c2..4c4b3b7 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -531,7 +531,26 @@ rtl_split_block (basic_block bb, void *insnp)
       insn = first_insn_after_basic_block_note (bb);
 
       if (insn)
-	insn = PREV_INSN (insn);
+	{
+	  rtx next = insn;
+
+	  insn = PREV_INSN (insn);
+
+	  /* If the block contains only debug insns, insn would have
+	     been NULL in a non-debug compilation, and then we'd end
+	     up emitting a DELETED note.  For -fcompare-debug
+	     stability, emit the note too.  */
+	  if (insn != BB_END (bb)
+	      && DEBUG_INSN_P (next)
+	      && DEBUG_INSN_P (BB_END (bb)))
+	    {
+	      while (next != BB_END (bb) && DEBUG_INSN_P (next))
+		next = NEXT_INSN (next);
+
+	      if (next == BB_END (bb))
+		emit_note_after (NOTE_INSN_DELETED, next);
+	    }
+	}
       else
 	insn = get_last_insn ();
     }
@@ -566,11 +585,15 @@ rtl_merge_blocks (basic_block a, basic_block b)
 {
   rtx b_head = BB_HEAD (b), b_end = BB_END (b), a_end = BB_END (a);
   rtx del_first = NULL_RTX, del_last = NULL_RTX;
+  rtx b_debug_start = b_end, b_debug_end = b_end;
   int b_empty = 0;
 
   if (dump_file)
     fprintf (dump_file, "merging block %d into block %d\n", b->index, a->index);
 
+  while (DEBUG_INSN_P (b_end))
+    b_end = PREV_INSN (b_debug_start = b_end);
+
   /* If there was a CODE_LABEL beginning B, delete it.  */
   if (LABEL_P (b_head))
     {
@@ -636,9 +659,21 @@ rtl_merge_blocks (basic_block a, basic_block b)
   /* Reassociate the insns of B with A.  */
   if (!b_empty)
     {
-      update_bb_for_insn_chain (a_end, b_end, a);
+      update_bb_for_insn_chain (a_end, b_debug_end, a);
 
-      a_end = b_end;
+      a_end = b_debug_end;
+    }
+  else if (b_end != b_debug_end)
+    {
+      /* Move any deleted labels and other notes between the end of A
+	 and the debug insns that make up B after the debug insns,
+	 bringing the debug insns into A while keeping the notes after
+	 the end of A.  */
+      if (NEXT_INSN (a_end) != b_debug_start)
+	reorder_insns_nobb (NEXT_INSN (a_end), PREV_INSN (b_debug_start),
+			    b_debug_end);
+      update_bb_for_insn_chain (b_debug_start, b_debug_end, a);
+      a_end = b_debug_end;
     }
 
   df_bb_delete (b->index);
@@ -2162,6 +2197,11 @@ purge_dead_edges (basic_block bb)
   bool found;
   edge_iterator ei;
 
+  if (DEBUG_INSN_P (insn) && insn != BB_HEAD (bb))
+    do
+      insn = PREV_INSN (insn);
+    while ((DEBUG_INSN_P (insn) || NOTE_P (insn)) && insn != BB_HEAD (bb));
+
   /* If this instruction cannot trap, remove REG_EH_REGION notes.  */
   if (NONJUMP_INSN_P (insn)
       && (note = find_reg_note (insn, REG_EH_REGION, NULL)))
@@ -2182,10 +2222,10 @@ purge_dead_edges (basic_block bb)
 	 latter can appear when nonlocal gotos are used.  */
       if (e->flags & EDGE_EH)
 	{
-	  if (can_throw_internal (BB_END (bb))
+	  if (can_throw_internal (insn)
 	      /* If this is a call edge, verify that this is a call insn.  */
 	      && (! (e->flags & EDGE_ABNORMAL_CALL)
-		  || CALL_P (BB_END (bb))))
+		  || CALL_P (insn)))
 	    {
 	      ei_next (&ei);
 	      continue;
@@ -2193,7 +2233,7 @@ purge_dead_edges (basic_block bb)
 	}
       else if (e->flags & EDGE_ABNORMAL_CALL)
 	{
-	  if (CALL_P (BB_END (bb))
+	  if (CALL_P (insn)
 	      && (! (note = find_reg_note (insn, REG_EH_REGION, NULL))
 		  || INTVAL (XEXP (note, 0)) >= 0))
 	    {
@@ -2771,7 +2811,8 @@ rtl_block_ends_with_call_p (basic_block bb)
   while (!CALL_P (insn)
 	 && insn != BB_HEAD (bb)
 	 && (keep_with_call_p (insn)
-	     || NOTE_P (insn)))
+	     || NOTE_P (insn)
+	     || DEBUG_INSN_P (insn)))
     insn = PREV_INSN (insn);
   return (CALL_P (insn));
 }