[committed] Add testcase for PR tree-optimization/71854

[Jakub Jelinek]

Hi!

This PR has been fixed in r244218 aka the PR78997 fix.
I've tested the testcase on x86_64-linux with -m32/-m64 (without/with
the PR78997 fix) and committed to trunk as obvious.

2017-01-17  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/71854
        * gcc.dg/vect/pr71854.c: New test.

--- gcc/testsuite/gcc.dg/vect/pr71854.c.jj      2017-01-17 16:46:29.366816678 
+0100
+++ gcc/testsuite/gcc.dg/vect/pr71854.c 2017-01-17 16:47:16.442209553 +0100
@@ -0,0 +1,25 @@
+/* PR tree-optimization/71854 */
+/* { dg-do compile } */
+/* { dg-additional-options "-O3 -ftree-loop-if-convert" } */
+
+char a, f = 1;
+int b, c, e[8];
+short d;
+
+short
+foo (short x)
+{
+  return x >= 2 || x >> c ? x : x << c;
+}
+
+int
+main ()
+{
+  while (f)
+    for (d = 0; d <= 7; d++)
+      {
+       f = 7 >> b ? a : a << b;
+       e[d] = foo (f);
+      }
+  return 0;
+}

        Jakub