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Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."

From: Robert Dewar <dewar at adacore dot com>
To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
Cc: autoconf-patches at gnu dot org, bosch at adacore dot com, bug-gnulib at gnu dot org, dberlin at dberlin dot org, eggert at cs dot ucla dot edu, gcc at gcc dot gnu dot org, richard dot guenther at gmail dot com
Date: Tue, 02 Jan 2007 09:06:09 -0500
Subject: Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
References: <200612300047.kBU0lFwk014817@localhost.localdomain> <87lkkosz1n.fsf@penguin.cs.ucla.edu> <45970416.80407@adacore.com> <8764bssikm.fsf@penguin.cs.ucla.edu> <571f6b510612310047r3b7ef9acl4a0ab082e88e17a3@mail.gmail.com> <87bqlkmm3r.fsf@penguin.cs.ucla.edu> <4aca3dc20612310641n78e8898euf1c003444e2303eb@mail.gmail.com> <84fc9c000612310645h67066c70vf9eb11af74b639a7@mail.gmail.com> <4aca3dc20612311613r2992db50o851c7d73603b42ef@mail.gmail.com> <22C62FE7-259E-43F7-9DB5-5F3A9CF574E2@adacore.com> <84fc9c000701020204v5e5ad239uec526652ff18eedc@mail.gmail.com> <459A64EF.1090801@adacore.com> <10701021405.AA01874@vlsi1.ultra.nyu.edu>

Richard Kenner wrote:

Then we have two switches:

-fstandard
which allows all optimizations (name can be changed, I
don't care about the name)
-fwrapv
which changes the semantics to require wrapping in
all cases (including loops)
What about -fno-wrapv for the first?


Possible .. my view was that it is probably not necessary
to distinguish the various subcases which arise now or in
the future of aggressive optimization opportunities based
on assumption of strict standard semantics.

For example, for me in -fstandard, I would tolerate the
"dewar password check example" being optimized to remove
the password check.

References:
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Daniel Berlin
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Geert Bosch
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Richard Guenther
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Robert Dewar
- Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
  - From: Richard Kenner

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