re PR tree-optimization/69399 (wrong code with -O and int128)

	PR tree-optimization/69399
	* wide-int.h (wi::lrshift): For larger precisions, only
	use fast path if shift is known to be < HOST_BITS_PER_WIDE_INT.

	* gcc.dg/torture/pr69399.c: New test.

From-SVN: r232869

gcc/ChangeLog

+2016-01-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/69399
+	* wide-int.h (wi::lrshift): For larger precisions, only
+	use fast path if shift is known to be < HOST_BITS_PER_WIDE_INT.
+
 2016-01-27  Claudiu Zissulescu  <claziss@synopsys.com>
 
         * config/arc/predicates.md (proper_comparison_operator): Reject

gcc/testsuite/ChangeLog

+2016-01-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/69399
+	* gcc.dg/torture/pr69399.c: New test.
+
 2016-01-27  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc.dg/tree-ssa/ssa-dom-cse-2.c: XFAIL on SPARC 64-bit.

gcc/testsuite/gcc.dg/torture/pr69399.c

+/* { dg-do run { target int128 } } */
+
+static unsigned __attribute__((noinline, noclone))
+foo (unsigned long long u)
+{
+  unsigned __int128 v = u | 0xffffff81U;
+  v >>= 64;
+  return v;
+}
+
+int
+main ()
+{
+  unsigned x = foo (27);
+  if (x != 0)
+    __builtin_abort ();
+  return 0;
+}

gcc/wide-int.h

@@ -2909,7 +2909,9 @@ wi::lrshift (const T1 &x, const T2 &y)
 	 For variable-precision integers like wide_int, handle HWI
 	 and sub-HWI integers inline.  */
       if (STATIC_CONSTANT_P (xi.precision > HOST_BITS_PER_WIDE_INT)
-	  ? xi.len == 1 && xi.val[0] >= 0
+	  ? (shift < HOST_BITS_PER_WIDE_INT
+	     && xi.len == 1
+	     && xi.val[0] >= 0)
 	  : xi.precision <= HOST_BITS_PER_WIDE_INT)
 	{
 	  val[0] = xi.to_uhwi () >> shift;