This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: Fix PR 53743 and other -freorder-blocks-and-partition failures (issue6823047)
- From: Jan Hubicka <hubicka at ucw dot cz>
- To: Steven Bosscher <stevenb dot gcc at gmail dot com>
- Cc: Jan Hubicka <hubicka at ucw dot cz>, Teresa Johnson <tejohnson at google dot com>, Xinliang David Li <davidxl at google dot com>, Diego Novillo <dnovillo at google dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Sat, 11 May 2013 14:28:14 +0200
- Subject: Re: Fix PR 53743 and other -freorder-blocks-and-partition failures (issue6823047)
- References: <CAAe5K+UW5MfcbaHCp+zWTGM9fZvKm6x6no9WDrOOKsap0vvxUQ at mail dot gmail dot com> <518C1851 dot 7030903 at google dot com> <CABu31nNmHHvnatfVcRucsnv8yhQ_Ud-SkunECcc7pLq+L20_gg at mail dot gmail dot com> <CAAkRFZ+ezFmGhxpOg1Md=rFV1=+jUu83ut_O1mHvz2rrcTDSOQ at mail dot gmail dot com> <CABu31nMPLetTv=vaXChvZit4o8sUsB_N8ppV8aKn_Ym9bL2dNA at mail dot gmail dot com> <CAAe5K+W=vUgyRm9_0bdJQKjUunQKMuWaCEPikowUHm35XWhHPw at mail dot gmail dot com> <CABu31nO9YR83bkBh1h+Kqh7PgDUFG9hP4ev68C++0SwL3NdsfQ at mail dot gmail dot com> <CAAe5K+WP=FQj4Hn3oLvXbry-bF44ABu9uH_t_ZCdtHvywYP2Cw at mail dot gmail dot com> <20130511111922 dot GA31362 at kam dot mff dot cuni dot cz> <CABu31nPvjpUFzw0mNtjczAFhoTqzyPXv6SWCNWxyO7NA1rzovw at mail dot gmail dot com>
> On Sat, May 11, 2013 at 1:19 PM, Jan Hubicka wrote:
> > Once -freorder-blocks-and-partition actually works, we should enable it by
> > default with -fprofile-generate (I recall I was trying to do that once, but
> > I am not sure what was outcome back then and why it did not happen).
> > That should get it tested with profiledbootstrap, too.
>
> I don't think -freorder-blocks-and-partition ever was stable enough to
> work with profiledbootstrap. From day one, it was fragile and not well
> covered in regression testing. I hope the verifiers will make life a
> bit more bearable, and that the fixes from Teresa will allow us to
> enable -freorder-blocks-and-partition with -fprofile-generate.
Yep, I hoped to slowly chase the bugs away but always got scared by
implementation details....
>
> Has anyone ever investigated the effects of
> -freorder-blocks-and-partition vs. the function splitting part if
> flag_partial_inlining (ipa-split.c)?
ipa-split really does splitting just in very special cases where partial
inlining seems possible and feasible. Plus one really split function into
two making it impossible to mix local vars. So it is not a replacement for
partitioning...
I was considering more aggressive outlininning of cold parts in ipa-split,
but did not get it implemented yet.
Honza
>
> Ciao!
> Steven