On Wed, 28 Sep 2016, Richard Biener wrote:
--- gcc/match.pd (revision 240565)
+++ gcc/match.pd (working copy)
@@ -147,12 +147,25 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(op @0 integer_onep)
(non_lvalue @0)))
-/* X / -1 is -X. */
(for div (trunc_div ceil_div floor_div round_div exact_div)
+ /* X / -1 is -X. */
(simplify
(div @0 integer_minus_onep@1)
(if (!TYPE_UNSIGNED (type))
- (negate @0))))
+ (negate @0)))
+ /* X / abs (X) is X < 0 ? -1 : 1. */
+ (simplify
+ (div @0 (abs @0))
Should this be div:C ?
+ (if ((INTEGRAL_TYPE_P (type) || VECTOR_INTEGER_TYPE_P (type))
+ && TYPE_OVERFLOW_UNDEFINED (type))
+ (cond (lt @0 { build_zero_cst (type); })
+ { build_minus_one_cst (type); } { build_one_cst (type); })))
How does that work for vectors? It ICEs for me at revision 240696
typedef int vec __attribute__((vector_size(16)));
vec f(vec x){
vec y=(x<0)?-x:x;
return x/y;
}
(I wasn't sure if you had added a feature to turn cond into vec_cond
automatically in some cases)
--
Marc Glisse
