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Re: [RFC] Make 4-stage PGO bootstrap really working
- From: Martin Liška <mliska at suse dot cz>
- To: Jan Hubicka <hubicka at ucw dot cz>
- Cc: Markus Trippelsdorf <markus at trippelsdorf dot de>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Richard Biener <richard dot guenther at gmail dot com>
- Date: Thu, 14 Sep 2017 14:20:56 +0200
- Subject: Re: [RFC] Make 4-stage PGO bootstrap really working
- Authentication-results: sourceware.org; auth=none
- References: <f61115af-55e1-8d59-545f-295f7e5b53cb@suse.cz> <20170529050407.GA15061@x4> <9203f3a8-3aa4-292b-1f2d-6749d3e6d0f7@suse.cz> <20170619103713.GB72026@kam.mff.cuni.cz> <a1959943-f196-da67-e391-3901ffe68d28@suse.cz>
PING^1
On 08/30/2017 11:45 AM, Martin Liška wrote:
> Hi.
>
> This is follow up which I've just noticed. Main problem we have is that
> an instrumented compiler w/ -fprofile-generate (built in $OBJDIR/gcc subfolder)
> will generate all *.gcda files in a same dir as *.o files. That's problematic
> because we then have *.gcda files spread in 'profile' subfolder (because profile'
> compiler builds libgcc) and 'train' subfolder. Eventually in 'feedback' stage
> we don't load any *.gcda files :/
>
> Well I really hope we need to set -fprofile-generate=$folder to a $folder. There comes
> second problem: all *.gcda files are created as $folder/$aux_base_name.gcda which makes
> it useless as we multiple same file names:
>
> $ find . -name expr.c
> ./libcpp/expr.c
> ./gcc/expr.c
>
> Thus I suggest patch #0001 that appends full path of current work dir. Patch #0002 sets
> a folder for PGO bootstrap. So far so good with a small exception: conftest.gcda files
> that trigger -Wcoverage-mismatch. Can we remove these before a stage? Do we do a similar
> thing somewhere?
>
> Thoughts?
> Thanks,
> Martin
>