On 11/09/2016 10:13 PM, Segher Boessenkool wrote:
* simplify-rtx.c (simplify_binary_operation_1): Simplify
(xor (and (xor A B) C) B) to (ior (and A C) (and B ~C)) and
(xor (and (xor A B) C) B) to (ior (and A ~C) (and B C)) if C
is a const_int.
I think one of the xors should have A as the second operand.
+ /* If we have (xor (and (xor A B) C) A) with C a constant we can instead
+ do (ior (and A ~C) (and B C)) which is a machine instruction on some
+ machines, and also has shorter instruction path length. */
+ if (GET_CODE (op0) == AND
Comments doesn't line up with the if/else on my monitor; could be email
damage but please check.
Other than that, I think it does qualify as a simplification (or at
least an improvement), so OK. Would be nice to check for it with a testcase.
Bernd
