simplify-rtx.c (simplify_plus_minus): Negate constant iff its neg field is…

simplify-rtx.c (simplify_plus_minus): Negate constant iff its neg field is different to previous argument's neg field.

	* simplify-rtx.c (simplify_plus_minus): Negate constant iff its neg
	field is different to previous argument's neg field.

	* gcc.c-torture/execute/20011019-1.c: New test.

From-SVN: r46356

gcc/ChangeLog

+2001-10-19  Jakub Jelinek  <jakub@redhat.com>
+
+	* simplify-rtx.c (simplify_plus_minus): Negate constant iff its neg
+	field is different to previous argument's neg field.
+
 Fri Oct 19 15:24:39 2001  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
 	* final.c (get_decl_from_op): New function.

gcc/simplify-rtx.c

@@ -1882,7 +1882,7 @@ simplify_plus_minus (code, mode, op0, op1)
       && CONSTANT_P (ops[n_ops - 2].op))
     {
       HOST_WIDE_INT value = INTVAL (ops[n_ops - 1].op);
-      if (ops[n_ops - 1].neg)
+      if (ops[n_ops - 1].neg ^ ops[n_ops - 2].neg)
 	value = -value;
       ops[n_ops - 2].op = plus_constant (ops[n_ops - 2].op, value);
       n_ops--;

gcc/testsuite/ChangeLog

+2001-10-19  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.c-torture/execute/20011019-1.c: New test.
+
 2001-10-19  NIIBE Yutaka  <gniibe@m17n.org>
 
 	* gcc.c-torture/execute/ieee/ieee.exp: Change sh-*-* to sh*-*-*.

gcc/testsuite/gcc.c-torture/execute/20011019-1.c

+extern void exit (int);
+extern void abort (void);
+
+struct { int a; int b[5]; } x;
+int *y;
+
+int foo (void)
+{
+  return y - x.b;
+}
+
+int main (void)
+{
+  y = x.b;
+  if (foo ())
+    abort ();
+  exit (0);
+}