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Re: [PATCH] Fix optimization regression in constant folder
- From: "Richard Guenther" <richard dot guenther at gmail dot com>
- To: "Eric Botcazou" <ebotcazou at adacore dot com>
- Cc: "Ian Lance Taylor" <iant at google dot com>, "Richard Kenner" <kenner at vlsi1 dot ultra dot nyu dot edu>, gcc-patches at gcc dot gnu dot org, mark at codesourcery dot com, matz at suse dot de
- Date: Sun, 14 Oct 2007 12:31:20 +0200
- Subject: Re: [PATCH] Fix optimization regression in constant folder
- References: <200709171539.26653.ebotcazou@adacore.com> <10710120240.AA03734@vlsi1.ultra.nyu.edu> <m3wsttymh6.fsf@localhost.localdomain> <200710141225.08559.ebotcazou@adacore.com>
On 10/14/07, Eric Botcazou <ebotcazou@adacore.com> wrote:
> > 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.
>
> From my point of view, your proposal (TYPE_IGNORE_OVERFLOWS +
> TYPE_OVERFLOW_WRAPS) is OK.
I don't want to have TYPE_IGNORE_OVERFLOWS. Matters are complicated
enough already. I also like you to revisit the decision to make Ada sizetype
signed. If there are optimization regressions for expressions created by
stor-layout.c solve them there, as that is the place where enough knowledge
about the involved magnitudes is available.
Richard.