re PR middle-end/68785 (valgrind reports issues with folding on x86_64)

	PR tree-optimization/68785
	* gimple-fold.c (fold_ctor_reference): Pass return value from
	native_encode_expr to native_interpret_expr.
	* tree-ssa-sccvn.c (fully_constant_vn_reference_p): Likewise.

	* gcc.dg/pr68785.c: New test.

From-SVN: r231499

gcc/ChangeLog

+2015-12-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/68785
+	* gimple-fold.c (fold_ctor_reference): Pass return value from
+	native_encode_expr to native_interpret_expr.
+	* tree-ssa-sccvn.c (fully_constant_vn_reference_p): Likewise.
+
 2015-12-10  Richard Biener  <rguenther@suse.de>
 
 	PR ipa/68331

gcc/gimple-fold.c

@@ -5495,9 +5495,10 @@ fold_ctor_reference (tree type, tree ctor, unsigned HOST_WIDE_INT offset,
       && size <= MAX_BITSIZE_MODE_ANY_MODE)
     {
       unsigned char buf[MAX_BITSIZE_MODE_ANY_MODE / BITS_PER_UNIT];
-      if (native_encode_expr (ctor, buf, size / BITS_PER_UNIT,
-			      offset / BITS_PER_UNIT) > 0)
-	return native_interpret_expr (type, buf, size / BITS_PER_UNIT);
+      int len = native_encode_expr (ctor, buf, size / BITS_PER_UNIT,
+				    offset / BITS_PER_UNIT);
+      if (len > 0)
+	return native_interpret_expr (type, buf, len);
     }
   if (TREE_CODE (ctor) == CONSTRUCTOR)
     {

gcc/testsuite/ChangeLog

+2015-12-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/68785
+	* gcc.dg/pr68785.c: New test.
+
 2015-12-10  Richard Biener  <rguenther@suse.de>
 
 	PR ipa/68331

gcc/testsuite/gcc.dg/pr68785.c

+/* PR tree-optimization/68785 */
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+int
+foo (void)
+{
+  return *(int *) "";
+}

gcc/tree-ssa-sccvn.c

@@ -1370,8 +1370,9 @@ fully_constant_vn_reference_p (vn_reference_t ref)
 	  else
 	    {
 	      unsigned char buf[MAX_BITSIZE_MODE_ANY_MODE / BITS_PER_UNIT];
-	      if (native_encode_expr (ctor, buf, size, off) > 0)
-		return native_interpret_expr (ref->type, buf, size);
+	      int len = native_encode_expr (ctor, buf, size, off);
+	      if (len > 0)
+		return native_interpret_expr (ref->type, buf, len);
 	    }
 	}
     }