Re: [PATCH] Another fix for decide_alg (PR target/70062)

[Uros Bizjak <ubizjak at gmail dot com>]

On Thu, Mar 3, 2016 at 9:16 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> Before my recent decide_alg change, *dynamic_check == -1 was indeed
> guaranteed, because any_alg_usable_p doesn't depend on the arguments of
> decide_alg that might change during recursive call, so we'd only recurse if
> it wouldn't set *dynamic_check.  But, if we give up because we'd otherwise
> recurse infinitely, we can set *dynamic_check to 128.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
>
> 2016-03-03  Jakub Jelinek  <jakub@redhat.com>
>
>         PR target/70062
>         * config/i386/i386.c (decide_alg): If
>         TARGET_INLINE_STRINGOPS_DYNAMICALLY, allow *dynamic_check to be also
>         128 from the recursive call.
>
>         * gcc.target/i386/pr70062.c: New test.

I don't like the fact that *dynamic_check is set to max (which is 0
with your testcase) when recursion avoidance code already set it to
"something reasonable", together with loop_1_byte alg. What do you
think about attached (lightly tested) patch?

Uros.

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