fold-const.c (fold_widened_comparison): Do not allow sign-changes that change the result.

2008-04-08  Richard Guenther  <rguenther@suse.de>

	* fold-const.c (fold_widened_comparison): Do not allow
	sign-changes that change the result.

	* gcc.c-torture/execute/20080408-1.c: New testcase.

From-SVN: r134108

gcc/ChangeLog

+2008-04-08  Richard Guenther  <rguenther@suse.de>
+
+	* fold-const.c (fold_widened_comparison): Do not allow
+	sign-changes that change the result.
+
 2008-04-08  Janis Johnson  <janis187@us.ibm.com>
 
 	PR target/35839

gcc/fold-const.c

@@ -6721,7 +6721,11 @@ fold_widened_comparison (enum tree_code code, tree type, tree arg0, tree arg1)
        || TYPE_UNSIGNED (TREE_TYPE (arg0)) == TYPE_UNSIGNED (shorter_type))
       && (TREE_TYPE (arg1_unw) == shorter_type
 	  || (TYPE_PRECISION (shorter_type)
-	      >= TYPE_PRECISION (TREE_TYPE (arg1_unw)))
+	      > TYPE_PRECISION (TREE_TYPE (arg1_unw)))
+	  || ((TYPE_PRECISION (shorter_type)
+	       == TYPE_PRECISION (TREE_TYPE (arg1_unw)))
+	      && (TYPE_UNSIGNED (shorter_type)
+		  == TYPE_UNSIGNED (TREE_TYPE (arg1_unw))))
 	  || (TREE_CODE (arg1_unw) == INTEGER_CST
 	      && (TREE_CODE (shorter_type) == INTEGER_TYPE
 		  || TREE_CODE (shorter_type) == BOOLEAN_TYPE)

gcc/testsuite/ChangeLog

+2008-04-08  Richard Guenther  <rguenther@suse.de>
+
+	* gcc.c-torture/execute/20080408-1.c: New testcase.
+
 2008-04-08  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gnat.dg/pack6.adb: New test.

gcc/testsuite/gcc.c-torture/execute/20080408-1.c

+extern void abort (void);
+int main ()
+{
+  short ssi = 126;
+  unsigned short usi = 65280;
+  int fail = !(ssi < usi);
+  if (fail)
+    abort ();
+  return 0;
+}
+