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Re: new x86 cmpmemsi expander, and adjustments for cmpstrn*
- From: Alexandre Oliva <oliva at adacore dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Jan Hubicka <hubicka at ucw dot cz>, Uros Bizjak <ubizjak at gmail dot com>
- Date: Wed, 25 Sep 2019 22:45:33 -0300
- Subject: Re: new x86 cmpmemsi expander, and adjustments for cmpstrn*
- References: <orh85jzqyu.fsf@lxoliva.fsfla.org>
On Sep 10, 2019, Alexandre Oliva <oliva@adacore.com> wrote:
> This patchset fixes some latent problems in cmpstrn* patterns for x86,
> and introduces cmpmemsi for short fixed-size memcmp.
Ping? https://gcc.gnu.org/ml/gcc-patches/2019-09/msg00701.html
> Would it make sense to install the test program somewhere?
> make cmpstrnsi patterns safer
> for gcc/ChangeLog
> * config/i386/i386.md (cmpstrnsi): Create separate output
> count to pass to cmpstrnqi_nz_1 and ...
> (cmpstrnqi_1): ... this. Do not use a match_dup of the count
> input as an output. Preserve FLAGS_REG when length is zero.
> (*cmpstrnqi_1): Preserve FLAGS_REG when length is zero.
> x86 cmpmemsi pattern - single compare
> for gcc/ChangeLog
> * config/i386/i386.md (cmpmemsi): New pattern.
> extend x86 cmpmemsi to use loops
> for gcc/ChangeLog
> * config/i386/i386.md (cmpmemsi): Expand more than one
> fragment compare sequence depending on optimization level.
> (subcmpsi3): New expand pattern.
--
Alexandre Oliva, freedom fighter he/him https://FSFLA.org/blogs/lxo
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GNU Toolchain Engineer Free Software Evangelist
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