[committed] Add testcase for PR rtl-optimization/81020

[Jakub Jelinek]

Hi!

This testcase was fixed by Segher's r254875:
https://gcc.gnu.org/ml/gcc-patches/2017-11/msg00340.html
on the trunk, so I've committed it to trunk as obvious.
On release branches it still needs fixing.

2017-11-28  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/81020
	* gcc.dg/pr81020.c: New test.

--- gcc/testsuite/gcc.dg/pr81020.c.jj	2017-11-27 18:49:06.659907687 +0100
+++ gcc/testsuite/gcc.dg/pr81020.c	2017-11-27 18:49:00.431982443 +0100
@@ -0,0 +1,23 @@
+/* PR rtl-optimization/81020 */
+/* { dg-do run } */
+/* { dg-options "-O -fno-tree-bit-ccp -fno-tree-coalesce-vars -fno-tree-vrp" } */
+
+unsigned v = 4;
+
+unsigned long long __attribute__((noipa))
+foo (unsigned x)
+{
+  unsigned a = v;
+  a &= 1;
+  x |= 0 < a;
+  a >>= 31;
+  return x + a;
+}
+
+int
+main ()
+{
+  if (foo (2) != 2)
+    __builtin_abort ();
+  return 0;
+}

	Jakub