On Sat, Nov 5, 2022 at 10:03 AM Zhongyunde via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > > > -----Original Message----- > > From: Andrew Pinski [mailto:pins...@gcc.gnu.org] > > Sent: Saturday, November 5, 2022 2:34 PM > > To: Zhongyunde <zhongyu...@huawei.com> > > Cc: hongtao....@intel.com; gcc-patches@gcc.gnu.org; Zhangwen(Esan) > > <zwzhangwen.zh...@huawei.com>; Weiwei (weiwei, Compiler) > > <weiwe...@huawei.com>; zhong_1985...@163.com > > Subject: Re: [PATCH] [PHIOPT] Add A ? B + CST : B match and simplify > > optimizations > > > > On Fri, Nov 4, 2022 at 11:17 PM Zhongyunde <zhongyu...@huawei.com> > > wrote: > > > > > > hi, > > > This patch is try to fix the issue > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107190, > > > would you like to give me some suggestion, thanks. > > > > This seems like a "simplified" version of > > https://gcc.gnu.org/pipermail/gcc-patches/2021-November/584411.html > > which just handles power of 2 constants where we know the cond will be > > removed. > > We could do even more "simplified" of 1 if needed really. > > What is the IR before PHI-OPT? Is it just + 1? > > Thanks for your attention. It is + 4294967296 before PHI-OPT (See detail > https://gcc.godbolt.org/z/6zEc6ja1z) > So we should keep matching the power of 2 constants ? > > > Also your pattern can be simplified to use integer_pow2p in the match part > > instead of INTEGER_CST. > > > Apply your comment, thanks
How does the patch fix the mentioned bug? match.pd patterns should make things "simpler" but x + (a << C') isn't simpler than a ? x + C : x. It looks you are targeting PHI-OPT here, so maybe instead extend value_replacement to handle this case, it does look similar to the case with neutral/absorbing element there? Richard. > > > Thanks, > > Andrew > >
