[PATCH] PR63676, exit tree fold when node be TREE_CLOBBER_P

  gcc/
    PR tree-optimization/63676
    * gimple-fold.c (fold_gimple_assign): Do not fold node when
    TREE_CLOBBER_P be true.

From-SVN: r217215

gcc/ChangeLog

+2014-11-07  Jiong Wang  <jiong.wang@arm.com>
+2014-11-07  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/63676
+	* gimple-fold.c (fold_gimple_assign): Do not fold node when
+	TREE_CLOBBER_P be true.
+
 2014-11-07  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/63770

gcc/gimple-fold.c

@@ -320,6 +320,9 @@ fold_gimple_assign (gimple_stmt_iterator *si)
       {
         tree rhs = gimple_assign_rhs1 (stmt);
 
+	if (TREE_CLOBBER_P (rhs))
+	  return NULL_TREE;
+
 	if (REFERENCE_CLASS_P (rhs))
 	  return maybe_fold_reference (rhs, false);