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Re: [RFC] Improve Tree-SSA if-conversion - convergence of efforts
- From: Tehila Meyzels <TEHILA at il dot ibm dot com>
- To: Michael Matz <matz at suse dot de>
- Cc: Daniel Berlin <dberlin at dberlin dot org>, dpatel at apple dot com, gcc at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org, Revital1 Eres <ERES at il dot ibm dot com>, trevor_smigiel at playstation dot sony dot com, Ulrich Weigand <Ulrich dot Weigand at de dot ibm dot com>, Victor Kaplansky <VICTORK at il dot ibm dot com>
- Date: Mon, 6 Aug 2007 15:13:15 +0300
- Subject: Re: [RFC] Improve Tree-SSA if-conversion - convergence of efforts
Michael Matz <matz@suse.de> wrote on 31/07/2007 18:05:53:
> Hi,
>
> On Tue, 31 Jul 2007, Daniel Berlin wrote:
>
> > > 2. Store-sinking/load hoisting may have an overhead and may degrade
> > > performance unless the relevant conditional branch gets if-converted.
> >
> > I agree with you for conditional stores/loads.
> >
> > The unconditional store/load stuff, however, is exactly what
> > tree-ssa-sink was meant to do, and belongs there (this is #3 above).
I'm
> > certainly going to fight tooth and nail against trying to shoehorn
> > unconditional store sinking into if-conv.
>
> FWIW I also agree that handling unconditional stores/loads does not
belong
> in if-conv (or phi-opt), but in ssa-sink (or some similar transformation
> which can or can not use value numbers and the like).
OK.
And what's your opinion WRT conditional loads/stores?
Since you've sent your conditional store transformation patch,
I guess the meaning could be rewriting it on the top of tree-if-conv.
Tehila.
>
>
> Ciao,
> Michael.