fold-const.c (tree_expr_nonnegative_p): Only return true for ABS_EXPR when…

fold-const.c (tree_expr_nonnegative_p): Only return true for ABS_EXPR when flag_wrapv is false because of INT_MIN.

2005-07-19  James A. Morrison  <phython@gcc.gnu.org>

        * fold-const.c (tree_expr_nonnegative_p): Only return true for
        ABS_EXPR when flag_wrapv is false because of INT_MIN.
        (tree_expr_nonzero_p): Always call tree_expr_nonzero_p on the argument
        of an ABS_EXPR.
        (fold_unary): Always fold ABS_EXPR<ABS_EXPR<x>> into
        ABS_EXPR<x>.

From-SVN: r102184

gcc/ChangeLog

+2005-07-19  James A. Morrison  <phython@gcc.gnu.org>
+
+	* fold-const.c (tree_expr_nonnegative_p): Only return true for
+	ABS_EXPR when flag_wrapv is false because of INT_MIN.
+	(tree_expr_nonzero_p): Always call tree_expr_nonzero_p on the argument
+	of an ABS_EXPR.
+	(fold_unary): Always fold ABS_EXPR<ABS_EXPR<x>> into
+	ABS_EXPR<x>.
+
 2005-07-20  Giovanni Bajo  <giovannibajo@libero.it>
 
 	Make CONSTRUCTOR use VEC to store initializers.

gcc/fold-const.c

@@ -6827,7 +6827,8 @@ fold_unary (enum tree_code code, tree type, tree op0)
 						    TREE_TYPE (targ0),
 						    targ0));
 	}
-      else if (tree_expr_nonnegative_p (arg0))
+      /* ABS_EXPR<ABS_EXPR<x>> = ABS_EXPR<x> even if flag_wrapv is on.  */
+      else if (tree_expr_nonnegative_p (arg0) || TREE_CODE (arg0) == ABS_EXPR)
 	return arg0;
 
       /* Strip sign ops from argument.  */
@@ -10527,7 +10528,11 @@ tree_expr_nonnegative_p (tree t)
   switch (TREE_CODE (t))
     {
     case ABS_EXPR:
-      return 1;
+      /* We can't return 1 if flag_wrapv is set because
+	 ABS_EXPR<INT_MIN> = INT_MIN.  */
+      if (!flag_wrapv)
+        return 1;
+      break;
 
     case INTEGER_CST:
       return tree_int_cst_sgn (t) >= 0;
@@ -10804,8 +10809,7 @@ tree_expr_nonzero_p (tree t)
   switch (TREE_CODE (t))
     {
     case ABS_EXPR:
-      if (!TYPE_UNSIGNED (type) && !flag_wrapv)
-	return tree_expr_nonzero_p (TREE_OPERAND (t, 0));
+      return tree_expr_nonzero_p (TREE_OPERAND (t, 0));
 
     case INTEGER_CST:
       /* We used to test for !integer_zerop here.  This does not work correctly

gcc/testsuite/ChangeLog

+2005-07-19  James A. Morrison  <phython@gcc.gnu.org>
+
+	* gcc.dg/fold-abs-1.c: New test.
+	* gcc.dg/fold-abs-2.c: New test.
+	* gcc.dg/fold-abs-3.c: New test.
+
 2005-07-20  Giovanni Bajo  <giovannibajo@libero.it>
 
 	Make CONSTRUCTOR use VEC to store initializers.

gcc/testsuite/gcc.dg/fold-abs-1.c

+/* { dg-do compile } */
+/* { dg-options "-O1 -fwrapv" } */
+#define ABS(x) (x > 0 ? x : -x)
+int f (int a, int b) {
+	if ((ABS(a) | b) != 0) return 1;
+	else return 0;
+}

gcc/testsuite/gcc.dg/fold-abs-2.c

+/* { dg-do run } */
+/* { dg-options "-O1 -fwrapv" } */
+#include <limits.h>
+void exit (int);
+void abort ();
+#define ABS(x) (x > 0 ? x : -x)
+int f (int a) {
+	if (ABS(a) >= 0) return 1;
+	else return 0;
+}
+
+int main (int argc, char *argv[]) {
+	if (f(INT_MIN))
+	  abort ();
+	else
+	  exit (0);
+}

gcc/testsuite/gcc.dg/fold-abs-3.c

+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-gimple -fwrapv" } */
+#define ABS(x) (x > 0 ? x : -x)
+int f (int a) {
+	return ABS (ABS(a));
+}
+
+/* { dg-final { scan-tree-dump-times "ABS" 1 "gimple" } } */
+/* { dg-final { cleanup-tree-dump "gimple" } } */