Remove a barrier when EDGE_CROSSING is removed (PR lto/88858).

2019-02-13  Martin Liska  <mliska@suse.cz>

	PR lto/88858
	* cfgrtl.c (remove_barriers_from_footer): New function.
	(try_redirect_by_replacing_jump): Use it.
	(cfg_layout_redirect_edge_and_branch): Likewise.

From-SVN: r268835

1 files changed, 27 insertions, 19 deletions

diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 172bdf5..56564c2 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -988,6 +988,31 @@ block_label (basic_block block)
   return as_a <rtx_code_label *> (BB_HEAD (block));
 }
 
+/* Remove all barriers from BB_FOOTER of a BB.  */
+
+static void
+remove_barriers_from_footer (basic_block bb)
+{
+  rtx_insn *insn = BB_FOOTER (bb);
+
+  /* Remove barriers but keep jumptables.  */
+  while (insn)
+    {
+      if (BARRIER_P (insn))
+	{
+	  if (PREV_INSN (insn))
+	    SET_NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
+	  else
+	    BB_FOOTER (bb) = NEXT_INSN (insn);
+	  if (NEXT_INSN (insn))
+	    SET_PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
+	}
+      if (LABEL_P (insn))
+	return;
+      insn = NEXT_INSN (insn);
+    }
+}
+
 /* Attempt to perform edge redirection by replacing possibly complex jump
    instruction by unconditional jump or removing jump completely.  This can
    apply only if all edges now point to the same block.  The parameters and
@@ -1051,26 +1076,8 @@ try_redirect_by_replacing_jump (edge e, basic_block target, bool in_cfglayout)
       /* Selectively unlink whole insn chain.  */
       if (in_cfglayout)
 	{
-	  rtx_insn *insn = BB_FOOTER (src);
-
 	  delete_insn_chain (kill_from, BB_END (src), false);
-
-	  /* Remove barriers but keep jumptables.  */
-	  while (insn)
-	    {
-	      if (BARRIER_P (insn))
-		{
-		  if (PREV_INSN (insn))
-		    SET_NEXT_INSN (PREV_INSN (insn)) = NEXT_INSN (insn);
-		  else
-		    BB_FOOTER (src) = NEXT_INSN (insn);
-		  if (NEXT_INSN (insn))
-		    SET_PREV_INSN (NEXT_INSN (insn)) = PREV_INSN (insn);
-		}
-	      if (LABEL_P (insn))
-		break;
-	      insn = NEXT_INSN (insn);
-	    }
+	  remove_barriers_from_footer (src);
 	}
       else
 	delete_insn_chain (kill_from, PREV_INSN (BB_HEAD (target)),
@@ -4396,6 +4403,7 @@ cfg_layout_redirect_edge_and_branch (edge e, basic_block dest)
 	  	 "Removing crossing jump while redirecting edge form %i to %i\n",
 		 e->src->index, dest->index);
       delete_insn (BB_END (src));
+      remove_barriers_from_footer (src);
       e->flags |= EDGE_FALLTHRU;
     }