--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/pr78540.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,27 @@
+/* PR middle-end/78540 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -Wno-psabi" } */
+/* { dg-additional-options "-march=core2" { target i?86-*-* x86_64-*-* } } */
+
+typedef unsigned __int128 V __attribute__ ((vector_size (64)));
+V g;
+
+static inline V
+foo (V a)
+{
+  V b, c;
+  c[0] = 0;
+  a += 2281559097;
+  c ^= 0;
+  b[0] = 0;
+  return 1 + c + b + a;
+}
+
+V
+bar ()
+{
+  V a = g, b = g;
+  a[1] ^= 1;
+  b[foo (a)[0] & 3] |= 1;
+  return b;
+}