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Date: Sat, 1 Aug 2009 13:10:13 +0300
Message-ID: <647fe9b10908010310of9d1a72k46c228264ead30de@mail.gmail.com>
Subject: Re: Some patches to DJGPP v2.04 (GCC-4.4.1 related)
From: Ozkan Sezer <sezeroz AT gmail DOT com>
To: djgpp-workers AT delorie DOT com
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On Sat, Aug 1, 2009 at 1:02 PM, Eli Zaretskii<eliz AT gnu DOT org> wrote:
>> Date: Sat, 1 Aug 2009 11:47:59 +0300
>> From: Ozkan Sezer <sezeroz AT gmail DOT com>
>>
>> Although you may want to build using
>> -Wstrict-aliasing=2 before finishing your work, because gcc
>> seems to hide some of the warnings _and_ may generate
>> bad code, and in some worse cases may not warn even
>> with that warning flag and still generate bad code which
>> happened to me once (that was with gcc-4.5, though..)
>
> Details, please: how can a warning option cause bad code generation?
>

Miscommunication, I think: What I suggest is that one
shouldn't rely plainly on -Wall to see strict aliasing
warnings, but also use -Wstrict-aliasing=2 to see if
there are more. If you miss those warnings, you _may_
(or may not) end up having bad binaries. Besides,
in some cases, even -Wstrict-aliasing=2 doesn't
report the aliasing violations and gcc can silently
generate bad code.  I hope this was clear enough.