re PR middle-end/28045 (Bitfield, &&, and optimization => bad code generation)

2006-06-19  Richard Guenther  <rguenther@suse.de>

	PR middle-end/28045
	* fold-const.c (operand_equal_p): Check if the argument types
	have the same precision before stripping NOPs.

	* gcc.dg/torture/pr28045.c: New testcase.

From-SVN: r114772

gcc/ChangeLog

+2006-06-19  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/28045
+	* fold-const.c (operand_equal_p): Check if the argument types
+	have the same precision before stripping NOPs.
+
 2006-06-19  Daniel Berlin  <dberlin@dberlin.org>
 
 	Fix PR tree-optimization/27341

gcc/fold-const.c

@@ -2497,6 +2497,11 @@ operand_equal_p (tree arg0, tree arg1, unsigned int flags)
   if (TYPE_UNSIGNED (TREE_TYPE (arg0)) != TYPE_UNSIGNED (TREE_TYPE (arg1)))
     return 0;
 
+  /* If both types don't have the same precision, then it is not safe
+     to strip NOPs.  */
+  if (TYPE_PRECISION (TREE_TYPE (arg0)) != TYPE_PRECISION (TREE_TYPE (arg1)))
+    return 0;
+
   STRIP_NOPS (arg0);
   STRIP_NOPS (arg1);
 

gcc/testsuite/ChangeLog

+2006-06-19  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/28045
+	* gcc.dg/torture/pr28045.c: New testcase.
+
 2006-06-18  Francois-Xavier Coudert  <coudert@clipper.ens.fr>
 
 	PR fortran/26801

gcc/testsuite/gcc.dg/torture/pr28045.c

+/* { dg-do run } */
+
+extern void abort(void);
+struct a
+{
+   unsigned int bits : 1;
+   signed long val : ((sizeof(long) * 8) - 1);
+};
+int Fnegate (struct a b)
+{
+  if ((-((long)b.val)) <= ((long) ((1UL << ((sizeof(long) * 8) - 2)) -1UL))
+      && (-((long)b.val)) >= (-(((long) ((1UL << ((sizeof(long) * 8) - 2)) -1UL))) - 1))
+     return 0 ;
+  abort ();
+}
+int main ()
+{
+  struct a b = {1, 1};
+  Fnegate (b);
+  return 0;
+}
+