On Wed, Jan 06, 2021 at 11:34:32AM +0800, Hongtao Liu via Gcc-patches wrote:
> > >>
> > >> Note there's a data dependency between them. insn 7 feeds insn 9. When
> > >> there's a data dependency, combiner patterns are usually the better
> > >> choice than peepholes. I think you'd be looking to match something
> > >> likethis (from the . combine dump):
> > >>
>
> Using combiner patterns, details is discussed in PR98348
>
> Boottrapped and regtested on x86_64-linux-gnu{-m32,} for both GCC10 and trunk.
> gcc/ChangeLog:
>
> PR target/96891
> PR target/98348
> * config/i386/sse.md (VI_128_256): New mode iterator.
> (*avx_cmp<mode>3_1, *avx_cmp<mode>3_2, *avx_cmp<mode>3_3,
> *avx_cmp<mode>3_4, *avx2_eq<mode>3, *avx2_pcmp<mode>3_1,
> *avx2_pcmp<mode>3_2, *avx2_gt<mode>3): New
> define_insn_and_split to lower avx512 vector comparison to avx
> version when dest is vector.
> (*<avx512>_cmp<mode>3,*<avx512>_cmp<mode>3,*<avx512>_ucmp<mode>3):
> define_insn_and_split for negating the comparison result.
> * config/i386/predicates.md (float_vector_all_ones_operand):
> New predicate.
> * config/i386/i386-expand.c (ix86_expand_sse_movcc): Use
> general NOT operator without UNSPEC_MASKOP.
>
> gcc/testsuite/ChangeLog:
>
> PR target/96891
> PR target/98348
> * gcc.target/i386/avx512bw-pr96891-1.c: New test.
> * gcc.target/i386/avx512f-pr96891-1.c: New test.
> * gcc.target/i386/avx512f-pr96891-2.c: New test.
> * gcc.target/i386/avx512f-pr96891-3.c: New test.
> * g++.target/i386/avx512f-pr96891-1.C: New test.
> * gcc.target/i386/bitwise_mask_op-3.c: Adjust testcase.
Ok for trunk. I'd prefer not to backport it to GCC 10.
Jakub
