re PR middle-end/52209 (wrong code at -O0)

	PR middle-end/52209
	* expr.c (expand_expr_real_2) <case BIT_NOT_EXPR>: Only expand using
	XOR for reduce_bit_field if type is unsigned.

	* gcc.c-torture/execute/pr52209.c: New test.

From-SVN: r184151

gcc/ChangeLog

+2012-02-13  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/52209
+	* expr.c (expand_expr_real_2) <case BIT_NOT_EXPR>: Only expand using
+	XOR for reduce_bit_field if type is unsigned.
+
 2012-02-12  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* config/sparc/sparc.h (CANNOT_CHANGE_MODE_CLASS): In 64-bit mode,

gcc/expr.c

@@ -8600,8 +8600,9 @@ expand_expr_real_2 (sepops ops, rtx target, enum machine_mode tmode,
       if (modifier == EXPAND_STACK_PARM)
 	target = 0;
       /* In case we have to reduce the result to bitfield precision
-	 expand this as XOR with a proper constant instead.  */
-      if (reduce_bit_field)
+	 for unsigned bitfield expand this as XOR with a proper constant
+	 instead.  */
+      if (reduce_bit_field && TYPE_UNSIGNED (type))
 	temp = expand_binop (mode, xor_optab, op0,
 			     immed_double_int_const
 			       (double_int_mask (TYPE_PRECISION (type)), mode),

gcc/testsuite/ChangeLog

+2012-02-13  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/52209
+	* gcc.c-torture/execute/pr52209.c: New test.
+
 2012-02-12  Mikael Morin  <mikael@gcc.gnu.org>
 
 	PR fortran/50981

gcc/testsuite/gcc.c-torture/execute/pr52209.c

+/* PR middle-end/52209 */
+
+extern void abort (void);
+struct S0 { int f2 : 1; } c;
+int b;
+
+int
+main ()
+{
+  b = -1 ^ c.f2;
+  if (b != -1)
+    abort ();
+  return 0;
+}