Re: [PATCH v3] tree-optimization/95821 - Convert strlen + strchr to memchr

[Noah Goldstein <goldstein.w.n@gmail.com>]

On Sat, Jul 9, 2022 at 8:59 AM Jeff Law via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
>
>
> On 6/21/2022 12:12 PM, Noah Goldstein via Gcc-patches wrote:
> > This patch allows for strchr(x, c) to the replace with memchr(x, c,
> > strlen(x) + 1) if strlen(x) has already been computed earlier in the
> > tree.
> >
> > Handles PR95821: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95821
> >
> > Since memchr doesn't need to re-find the null terminator it is faster
> > than strchr.
> >
> > bootstrapped and tested on x86_64-linux.
> >
> >       PR tree-optimization/95821
> >
> > gcc/
> >
> >       * tree-ssa-strlen.cc (strlen_pass::handle_builtin_strchr): Emit
> >       memchr instead of strchr if strlen already computed.
> >
> > gcc/testsuite/
> >
> >       * c-c++-common/pr95821-1.c: New test.
> >       * c-c++-common/pr95821-2.c: New test.
> >       * c-c++-common/pr95821-3.c: New test.
> >       * c-c++-common/pr95821-4.c: New test.
> >       * c-c++-common/pr95821-5.c: New test.
> >       * c-c++-common/pr95821-6.c: New test.
> >       * c-c++-common/pr95821-7.c: New test.
> >       * c-c++-common/pr95821-8.c: New test.
> Given Jakub's involvement to-date and the fact this touches
> tree-ssa-strlen.cc I think Jakub should have final ACK/NAK on this.
>
> jeff
>

Ping.