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

From: Vincent Lefevre
Subject: Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
Date: Sun, 31 Dec 2006 13:09:33 +0100
User-agent: Mutt/1.5.13-vl-r14963 (2006-12-20)

On 2006-12-30 20:07:09 -0500, Robert Dewar wrote:
>  In my view, this comparison optimization should not have been put in
>  without justification given that it clearly does affect the semantics
>  of real code. Indeed if you really see code like
>    if (a - 10 < 20)
>  in place of
>    if (a < 30)
>  a very likely explanation is that you are deliberately doing something
>  strange with wrap around, and should leave it alone.

I disagree concerning your "very likely explanation". This code
may come from the use of macros, in which case this has nothing
to do with wrap around.

Vincent Lefèvre <address@hidden> - Web: <>
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Work: CR INRIA - computer arithmetic / Arenaire project (LIP, ENS-Lyon)

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