This implements NEGATE_EXPR as 0 - X, re-using code we have for
MINUS_EXPR.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2011-08-12 Richard Guenther <rguent...@suse.de>
* tree-vrp.c (extract_range_from_unary_expr_1): Implement
-X as 0 - X.
Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c (revision 177671)
+++ gcc/tree-vrp.c (working copy)
@@ -2946,67 +2946,14 @@ extract_range_from_unary_expr_1 (value_r
/* Apply the operation to each end of the range and see what we end
up with. */
- if (code == NEGATE_EXPR
- && !TYPE_UNSIGNED (type))
+ if (code == NEGATE_EXPR)
{
- /* NEGATE_EXPR flips the range around. We need to treat
- TYPE_MIN_VALUE specially. */
- if (is_positive_overflow_infinity (vr0.max))
- min = negative_overflow_infinity (type);
- else if (is_negative_overflow_infinity (vr0.max))
- min = positive_overflow_infinity (type);
- else if (!vrp_val_is_min (vr0.max))
- min = fold_unary_to_constant (code, type, vr0.max);
- else if (needs_overflow_infinity (type))
- {
- if (supports_overflow_infinity (type)
- && !is_overflow_infinity (vr0.min)
- && !vrp_val_is_min (vr0.min))
- min = positive_overflow_infinity (type);
- else
- {
- set_value_range_to_varying (vr);
- return;
- }
- }
- else
- min = TYPE_MIN_VALUE (type);
-
- if (is_positive_overflow_infinity (vr0.min))
- max = negative_overflow_infinity (type);
- else if (is_negative_overflow_infinity (vr0.min))
- max = positive_overflow_infinity (type);
- else if (!vrp_val_is_min (vr0.min))
- max = fold_unary_to_constant (code, type, vr0.min);
- else if (needs_overflow_infinity (type))
- {
- if (supports_overflow_infinity (type))
- max = positive_overflow_infinity (type);
- else
- {
- set_value_range_to_varying (vr);
- return;
- }
- }
- else
- max = TYPE_MIN_VALUE (type);
- }
- else if (code == NEGATE_EXPR
- && TYPE_UNSIGNED (type))
- {
- if (!range_includes_zero_p (&vr0))
- {
- max = fold_unary_to_constant (code, type, vr0.min);
- min = fold_unary_to_constant (code, type, vr0.max);
- }
- else
- {
- if (range_is_null (&vr0))
- set_value_range_to_null (vr, type);
- else
- set_value_range_to_varying (vr);
- return;
- }
+ /* -X is simply 0 - X, so re-use existing code that also handles
+ anti-ranges fine. */
+ value_range_t zero = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
+ set_value_range_to_value (&zero, build_int_cst (type, 0), NULL);
+ extract_range_from_binary_expr_1 (vr, MINUS_EXPR, type, &zero, &vr0);
+ return;
}
else if (code == ABS_EXPR
&& !TYPE_UNSIGNED (type))
