re PR tree-optimization/80631 (Compiling with -O3 -mavx2 gives wrong code)

	PR tree-optimization/80631
	* gcc.target/i386/avx2-pr80631.c: New test.

From-SVN: r255701

gcc/testsuite/ChangeLog

 2017-12-15  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/80631
+	* gcc.target/i386/avx2-pr80631.c: New test.
+
 	* g++.dg/plugin/attribute_plugin.c (user_attr): Swap
 	affects_type_identity and handler fields, add NULL for exclude.
 

gcc/testsuite/gcc.target/i386/avx2-pr80631.c

+/* PR tree-optimization/80631 */
+/* { dg-do run } */
+/* { dg-options "-O2 -ftree-vectorize -mavx2 -fno-vect-cost-model" } */
+/* { dg-require-effective-target avx2 } */
+
+#include "avx2-check.h"
+
+#define N 8
+
+static void
+avx2_test (void)
+{
+  int v[N], k;
+  for(k = 0; k < N; k++)
+    v[k] = k;
+  v[0] = 77;
+  int found_index = -1;
+  for (k = 0; k < N; k++)
+    if (v[k] == 77)
+      found_index = k;
+  if (found_index != 0)
+    abort ();
+}