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*From*: Ian Lance Taylor <iant at google dot com>*To*: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)*Cc*: ebotcazou at adacore dot com, gcc-patches at gcc dot gnu dot org, mark at codesourcery dot com, matz at suse dot de, richard dot guenther at gmail dot com*Date*: 11 Oct 2007 21:40:21 -0700*Subject*: Re: [PATCH] Fix optimization regression in constant folder*References*: <200709171539.26653.ebotcazou@adacore.com> <200709301801.39718.ebotcazou@adacore.com> <m3r6kf3gyx.fsf@localhost.localdomain> <200710010127.59677.ebotcazou@adacore.com> <m3abr33dbp.fsf@localhost.localdomain> <10710010056.AA15609@vlsi1.ultra.nyu.edu> <Pine.LNX.4.64.0710010325340.23011@wotan.suse.de> <10710010257.AA21585@vlsi1.ultra.nyu.edu> <Pine.LNX.4.64.0710010454060.23011@wotan.suse.de> <10710010344.AA22633@vlsi1.ultra.nyu.edu> <470D0C50.4080506@codesourcery.com> <Pine.LNX.4.64.0710111658530.23011@wotan.suse.de> <10710111536.AA24058@vlsi1.ultra.nyu.edu> <Pine.LNX.4.64.0710111756080.23011@wotan.suse.de> <10710111616.AA25194@vlsi1.ultra.nyu.edu> <Pine.LNX.4.64.0710111828400.23011@wotan.suse.de> <10710111651.AA26098@vlsi1.ultra.nyu.edu> <Pine.LNX.4.64.0710111853060.23011@wotan.suse.de> <m3r6k13728.fsf@localhost.localdomain> <Pine.LNX.4.64.0710112011530.23011@wotan.suse.de> <10710111850.AA27 912@vlsi1.ultra.nyu.edu> <Pine.LNX.4.64.0710112057570.2 <m3ve9d1h27.fsf@localhost.localdomain> <10710120240.AA03734@vlsi1.ultra.nyu.edu>

kenner@vlsi1.ultra.nyu.edu (Richard Kenner) writes: > > But the rest of us don't understand the semantics of sizetypes. That > > is why we are trying to pin it down in terms of other flags. We > > understand what those other flags mean. > > The problem is that it's becoming clearer and clearer that the semantics of > sizetypes CAN'T be expressed in terms of those other flags! The flags aren't fixed in stone. In fact, I just introduced them earlier this year. So all this tells me is that we need to change the flags. I already proposed such a change (http://gcc.gnu.org/ml/gcc-patches/2007-10/msg00053.html). Nobody has yet explained why my proposal wouldn't work. > Essentially, what we have to do when we see a transformation that might > potentially be applied to sizetypes is to rely on our understanding of > the semantics of those operations to see whether or not that transformation > is safe or not. > > That set of decisions may or may not corespond to some other set of flags > that we're using for other (unrelated) types. I don't see it as a big deal > if it doesn't. Again, it's a big deal because at the moment most of the gcc maintainers don't understand the semantics. After all this discussion I still barely have a handle on what you want. You are talking in vague generalities, and you are unable to give us any actual code. It's no wonder we remain confused. Ian

**Follow-Ups**:**Re: [PATCH] Fix optimization regression in constant folder***From:*Mark Mitchell

**Re: [PATCH] Fix optimization regression in constant folder***From:*Richard Kenner

**Re: [PATCH] Fix optimization regression in constant folder***From:*Eric Botcazou

**References**:**Re: [PATCH] Fix optimization regression in constant folder***From:*Ian Lance Taylor

**Re: [PATCH] Fix optimization regression in constant folder***From:*Richard Kenner

**Re: [PATCH] Fix optimization regression in constant folder***From:*Michael Matz

**Re: [PATCH] Fix optimization regression in constant folder***From:*Richard Kenner

**Re: [PATCH] Fix optimization regression in constant folder***From:*Michael Matz

**Re: [PATCH] Fix optimization regression in constant folder***From:*Richard Kenner

**Re: [PATCH] Fix optimization regression in constant folder***From:*Mark Mitchell

**Re: [PATCH] Fix optimization regression in constant folder***From:*Michael Matz

**Re: [PATCH] Fix optimization regression in constant folder***From:*Richard Kenner

**Re: [PATCH] Fix optimization regression in constant folder***From:*Michael Matz

**Re: [PATCH] Fix optimization regression in constant folder***From:*Richard Kenner

**Re: [PATCH] Fix optimization regression in constant folder***From:*Michael Matz

**Re: [PATCH] Fix optimization regression in constant folder***From:*Richard Kenner

**Re: [PATCH] Fix optimization regression in constant folder***From:*Michael Matz

**Re: [PATCH] Fix optimization regression in constant folder***From:*Ian Lance Taylor

**Re: [PATCH] Fix optimization regression in constant folder***From:*Michael Matz

**Re: [PATCH] Fix optimization regression in constant folder***From:*Ian Lance Taylor

**Re: [PATCH] Fix optimization regression in constant folder***From:*Richard Kenner

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