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Re: [RFC] Enable virtual operands at -O0
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 15 Apr 2014 19:55 +0200
- Subject: Re: [RFC] Enable virtual operands at -O0
- Authentication-results: sourceware.org; auth=none
- References: <6691503 dot GtiFGFCv1P at polaris> <CAFiYyc0qC0=oPWf9QU5yW+AGrM5qLEW631LPv-6g8-FbtFvRBg at mail dot gmail dot com>
> ISTR some more ???/FIXMEs and/or special-casings we could remove with
> that. As followup, of course.
It would be better to remove them all at once, so if you have specifics...
> The single reason why we don't have virtual operands at -O0 is compile-time
> btw - SSA rewrite doesn't come for free. But I don't mind - still maybe
> a quick comparison of stage1-gcc compile-time with/without that patch
> would be interesting?
3m3.306s vs 3m3.041s for the 64-bit build of an earlier compiler version. The
difference doesn't seem to be much more noticeable on big preprocessed files,
e.g. combine.i or pt.i, but I'm not sure this means anything.
--
Eric Botcazou