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Re: GCC optimizes integer overflow: bug or feature?


From: Robert Dewar
Subject: Re: GCC optimizes integer overflow: bug or feature?
Date: Tue, 19 Dec 2006 08:41:13 -0500
User-agent: Thunderbird 1.5.0.8 (Windows/20061025)

Florian Weimer wrote:

Something like:

        GCC does not use the latitude given in C99 only to treat
        certain aspects of signed @samp{<<} as undefined: If the right
        operand @var{n} is non-negative and less than the width of the
        left operand @var{val}, the resulting value @address@hidden <<
        @var{n}} is guaranteed to be equal to @var{val} times 2 to the
        @var{n}th power under 2-complement arithmetic.

would probably settle the issue, but it's unwieldy.

Seems fine to me and completely clear, but in my experience, a lot
of people prefer to infer from examples than to read perfectly
clear defining text, so I would add an example.





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