re PR tree-optimization/51117 (rev.181172 causes glibc build failure)

	PR tree-optimization/51117
	* tree-eh.c (optimize_clobbers): Don't remove just one
	clobber, but all consecutive clobbers before RESX.
	Use gimple_clobber_p predicate.

From-SVN: r182177

gcc/ChangeLog

+2011-12-09  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/51117
+	* tree-eh.c (optimize_clobbers): Don't remove just one
+	clobber, but all consecutive clobbers before RESX.
+	Use gimple_clobber_p predicate.
+
 2011-12-09  Michael Meissner  <meissner@the-meissners.org>
 
 	* config/rs6000/rs6000.c (altivec_expand_builtin): Call

gcc/tree-eh.c

@@ -3180,17 +3180,13 @@ static void
 optimize_clobbers (basic_block bb)
 {
   gimple_stmt_iterator gsi = gsi_last_bb (bb);
-  for (gsi_prev (&gsi); !gsi_end_p (gsi);)
+  for (gsi_prev (&gsi); !gsi_end_p (gsi); gsi_prev (&gsi))
     {
       gimple stmt = gsi_stmt (gsi);
       if (is_gimple_debug (stmt))
-	{
-	  gsi_prev (&gsi);
-	  continue;
-	}
-      if (!gimple_assign_single_p (stmt)
-	  || TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME
-	  || !TREE_CLOBBER_P (gimple_assign_rhs1 (stmt)))
+	continue;
+      if (!gimple_clobber_p (stmt)
+	  || TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME)
 	return;
       unlink_stmt_vdef (stmt);
       gsi_remove (&gsi, true);