On Tue, Jul 21, 2015 at 11:16 AM, Hurugalawadi, Naveen <naveen.hurugalaw...@caviumnetworks.com> wrote: > Hi, > >>> handle exact_div differently, like fold-const.c does. >>> Then expressing ~1 with the result expression is really excessive - you >>> should simply build this with @1 - 1 if @1 is a power of two.
(*) > Thanks for the review and comments. > > Please find attached the modified patch as per your comments. > > Please review the same and let me know if any further modifications are > required. > > Regression Tested on X86_64. We already have +(simplify + (mult (exact_div @0 INTEGET_CST@1) @1) + @0) as /* (X /[ex] A) * A -> X. */ (simplify (mult (convert? (exact_div @0 @1)) @1) /* Look through a sign-changing conversion. */ (convert @0)) as before the comment applies to your second pattern. +(simplify + (mult (trunc_div @0 integer_pow2p@1) @1) + (bit_and @0 (negate @1))) This doesn't work for signed types at least. -1 / 2 * 2 == 0, not -2. Your previous patch correctly restricted this to unsigned types. Thanks, Richard. > Thanks, > Naveen > > gcc/testsuite/ChangeLog: > > 2015-07-21 Naveen H.S <naveen.hurugalaw...@caviumnetworks.com> > > PR middle-end/25530 > * gcc.dg/pr25530.c: New test. > > gcc/ChangeLog: > > 2015-07-21 Naveen H.S <naveen.hurugalaw...@caviumnetworks.com> > > PR middle-end/25530 > * match.pd (mult (exact_div @0 INTEGET_CST@1) @1) : New > simplifier. > (mult (trunc_div @0 integer_pow2p@1) @1) : New simplifier.
