https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118012
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |michael.collison at linaro dot
org
| |, rguenth at gcc dot gnu.org
--- Comment #3 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Seems it started at r13-4459 with a match.pd pattern that doesn't even try to
work out additional costs.
+/* ((x & 0x1) == 0) ? y : z <op> y -> (-(typeof(y))(x & 0x1) & z) <op> y */
+(for op (bit_xor bit_ior)
+ (simplify
+ (cond (eq zero_one_valued_p@0
+ integer_zerop)
+ @1
+ (op:c @2 @1))
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_PRECISION (type) > 1
+ && (INTEGRAL_TYPE_P (TREE_TYPE (@0))))
+ (op (bit_and (negate (convert:type @0)) @2) @1))))
+
+/* ((x & 0x1) == 0) ? z <op> y : y -> (-(typeof(y))(x & 0x1) & z) <op> y */
+(for op (bit_xor bit_ior)
+ (simplify
+ (cond (ne zero_one_valued_p@0
+ integer_zerop)
+ (op:c @2 @1)
+ @1)
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_PRECISION (type) > 1
+ && (INTEGRAL_TYPE_P (TREE_TYPE (@0))))
+ (op (bit_and (negate (convert:type @0)) @2) @1))))
+
