Looks like it caused PR71655 and therefore is not so safe :/ Ilya
2016-06-22 17:00 GMT+03:00 Ilya Enkovich <enkovich....@gmail.com>: > 2016-06-21 23:57 GMT+03:00 Jeff Law <l...@redhat.com>: >> On 06/16/2016 05:06 AM, Ilya Enkovich wrote: >>> >>> Hi, >>> >>> This patch fixes incorrect comparison vectorization for booleans. >>> The problem is that regular comparison which works for scalars >>> doesn't work for vectors due to different binary representation. >>> Also this never works for scalar masks. >>> >>> This patch replaces such comparisons with bitwise operations >>> which work correctly for both vector and scalar masks. >>> >>> Bootstrapped and regtested on x86_64-unknown-linux-gnu. Is it >>> OK for trunk? What should be done for gcc-6-branch? Port this >>> patch or just restrict vectorization for comparison of booleans? >>> >>> Thanks, >>> Ilya >>> -- >>> gcc/ >>> >>> 2016-06-15 Ilya Enkovich <ilya.enkov...@intel.com> >>> >>> PR middle-end/71488 >>> * tree-vect-patterns.c (vect_recog_mask_conversion_pattern): >>> Support >>> comparison of boolean vectors. >>> * tree-vect-stmts.c (vectorizable_comparison): Vectorize >>> comparison >>> of boolean vectors using bitwise operations. >>> >>> gcc/testsuite/ >>> >>> 2016-06-15 Ilya Enkovich <ilya.enkov...@intel.com> >>> >>> PR middle-end/71488 >>> * g++.dg/pr71488.C: New test. >>> * gcc.dg/vect/vect-bool-cmp.c: New test. >> >> OK. Given this is a code generation bug, I'll support porting this patch to >> the gcc-6 branch. Is there any reason to think that porting out be more >> risky than usual? It looks pretty simple to me, am I missing some subtle >> dependency? > > I don't feel this patch is too risky. I asked only because simple restriction > on masks comparison is even more safe. > > Thanks, > Ilya > > >> >> jeff >>
