On Mon, Jun 23, 2014 at 4:23 PM, Marc Glisse <marc.gli...@inria.fr> wrote: > On Mon, 23 Jun 2014, Richard Biener wrote: > >> On Mon, Jun 23, 2014 at 3:32 PM, Prathamesh Kulkarni >> <bilbotheelffri...@gmail.com> wrote: >>> >>> * match.pd: Mark operators in some bitwise and plus-minus >>> patterns to be commutative. >> >> >> /* A - (A +- B) -> -+ B */ >> (match_and_simplify >> - (minus @0 (plus @0 @1)) >> + (minus @0 (plus:c @0 @1)) >> (negate @0)) >> >> seems pointless > > > Why? a-(a+b) and a-(b+a) are both wanted and don't appear elsewhere in the > file, no? Should simplify to (negate @1) though.
Ah, indeed. So here commutation doesn't work because of correctness. Richard. > -- > Marc Glisse
