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Re: [PATCH][RFC] Do not error on inconsistent profiles (PR38977)
- From: Ian Lance Taylor <iant at google dot com>
- To: Richard Guenther <rguenther at suse dot de>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 27 Jan 2009 18:28:27 -0800
- Subject: Re: [PATCH][RFC] Do not error on inconsistent profiles (PR38977)
- References: <alpine.LNX.2.00.0901261509380.24314@zhemvz.fhfr.qr>
Richard Guenther <rguenther@suse.de> writes:
> It happens that some openSUSE packages do no longer build with GCC 4.4
> as they error on inconsistent profiles. In 4.3 this kind of
> inconsistency was simply ignored, now we have the possibility to
> "correct" them by smoothing - but this is not enabled by default, instead
> we now error by default.
>
> I suggest we revert to ignoring this kind of problem for 4.4 and
> turn on profile smoothing by default for 4.5 (it is quite late for 4.4
> now, and obviously this code-path has been not extensively tested).
>
> Comments?
>
> Thanks,
> Richard.
>
> 2009-01-26 Richard Guenther <rguenther@suse.de>
>
> PR tree-optimization/38977
> * profile.c (compute_branch_probabilities): Do not error on
> inconsistent profiles.
What if we change the error to a warning? As I understand it, the
corrupted profile may lead to optimizing based on meaningless data,
and it might be just as good to simply ignore the profiling data
entirely.
Or if the warning leads to -Werror issues, I suppose I'm OK with just
ignoring the corruption.
Ian