--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/vect/vect-over-widen-18.c	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,50 @@
+/* { dg-require-effective-target vect_int } */
+/* { dg-require-effective-target vect_shift } */
+/* { dg-require-effective-target vect_pack_trunc } */
+/* { dg-require-effective-target vect_unpack } */
+
+#include "tree-vect.h"
+
+#define N 1024
+
+/* This should be treated as an over-widening pattern: we can truncate
+   b to unsigned char after loading it and do all the computation in
+   unsigned char.  */
+
+void __attribute__ ((noipa))
+f (unsigned char *restrict a, unsigned short *restrict b)
+{
+  for (__INTPTR_TYPE__ i = 0; i < N; ++i)
+    {
+      unsigned short foo = ((b[i] & 0xef) | 0x80) + (a[i] << 4);
+      a[i] = foo;
+    }
+}
+
+int
+main (void)
+{
+  check_vect ();
+
+  unsigned char a[N];
+  unsigned short b[N];
+  for (int i = 0; i < N; ++i)
+    {
+      a[i] = i;
+      b[i] = i * 3;
+      asm volatile ("" ::: "memory");
+    }
+  f (a, b);
+  for (int i = 0; i < N; ++i)
+    if (a[i] != (unsigned char) ((((i * 3) & 0xef) | 0x80) + (i << 4)))
+      __builtin_abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* &} "vect" } } */
+/* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* |} "vect" } } */
+/* { dg-final { scan-tree-dump {vect_recog_over_widening_pattern: detected:[^\n]* <<} "vect" } } */
+/* { dg-final { scan-tree-dump {vector[^\n]*char} "vect" } } */
+/* { dg-final { scan-tree-dump-not {vector[^ ]* int} "vect" } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loop" 1 "vect" } } */