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Re: [PATCH x86] Increase PARAM_MAX_COMPLETELY_PEELED_INSNS when branch is costly
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: Evgeny Stupachenko <evstupac at gmail dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Jan Hubicka <hubicka at ucw dot cz>, Richard Biener <richard dot guenther at gmail dot com>, Uros Bizjak <ubizjak at gmail dot com>
- Date: Tue, 11 Nov 2014 17:30:58 +0100
- Subject: Re: [PATCH x86] Increase PARAM_MAX_COMPLETELY_PEELED_INSNS when branch is costly
- Authentication-results: sourceware.org; auth=none
- References: <CAOvf_xwBqY++PGRC_+1=rzHO18jvc+TP5mmR=PjYvGgm=63NuA at mail dot gmail dot com> <CAOvf_xzFR+x+FvUh7dXvvRC3K7=s2Mb3MzjofLnMzoHGNZmKTA at mail dot gmail dot com> <CAOvf_xz7NJrkmE=sVAPKQgfwytFqzvGG7H4ZRJxk-ByUtqpKrA at mail dot gmail dot com>
> 150 and 200 make Silvermont performance better on 173.applu (+8%) and
> 183.equake (+3%); Haswell spec2006 performance stays almost unchanged.
> Higher value of 300 leave the performance of mentioned tests
> unchanged, but add some regressions on other benchmarks.
>
> So I like 200 as well as 120 and 150, but can confirm performance
> gains only for x86.
IMO it's either 150 or 200. We chose 200 for our 4.9-based compiler because
this gave the performance boost without affecting the code size (on x86-64)
and because this was previously 400, but it's your call.
--
Eric Botcazou