re PR c/82437 (false-positive -Wtautological-compare warning with -std=gnu89)

	PR c/82437
	* c-warn.c (warn_tautological_bitwise_comparison): Use wi::to_wide
	instead of wide_int::from.

	* c-c++-common/Wtautological-compare-7.c: New test.

From-SVN: r253589

gcc/c-family/ChangeLog

+2017-10-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/82437
+	* c-warn.c (warn_tautological_bitwise_comparison): Use wi::to_wide
+	instead of wide_int::from.
+
 2017-10-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/82437

gcc/c-family/c-warn.c

@@ -362,8 +362,8 @@ warn_tautological_bitwise_comparison (location_t loc, tree_code code,
   int prec = MAX (TYPE_PRECISION (TREE_TYPE (cst)),
 		  TYPE_PRECISION (TREE_TYPE (bitopcst)));
 
-  wide_int bitopcstw = wide_int::from (bitopcst, prec, UNSIGNED);
-  wide_int cstw = wide_int::from (cst, prec, UNSIGNED);
+  wide_int bitopcstw = wi::to_wide (bitopcst, prec);
+  wide_int cstw = wi::to_wide (cst, prec);
 
   wide_int res;
   if (TREE_CODE (bitop) == BIT_AND_EXPR)

gcc/testsuite/ChangeLog

+2017-10-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/82437
+	* c-c++-common/Wtautological-compare-7.c: New test.
+
 2017-10-10  Bin Cheng  <bin.cheng@arm.com>
 
 	* gcc.dg/tree-ssa/ldist-34.c: New test.

gcc/testsuite/c-c++-common/Wtautological-compare-7.c

+/* PR c/82437 */
+/* { dg-do compile { target int32 } } */
+/* { dg-options "-Wtautological-compare" } */
+
+int
+foo (unsigned long long int x)
+{
+  if ((x | 0x190000000ULL) != -1879048192)	/* { dg-bogus "bitwise comparison always evaluates to" } */
+    return 0;
+  return 1;
+}