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Re: PATCH COMMITTED: gcc 4.2 support for -Wstrict-overflow/-fstrict-overflow


On 3/12/07, Andrew Pinski <pinskia@gmail.com> wrote:
On 11 Mar 2007 21:40:24 -0700, Ian Lance Taylor <iant@google.com> wrote:
> I have just committed the gcc 4.2 patch which adds support for
> -Wstrict-overflow and -fstrict-overflow, as previously approved.  A
> bunch of testing was required.  Lucky for me that Mark's release
> candidate was delayed.

Wait, this still introduces a missed optimization regression as
mentioned by Richard Guenther so why did you apply it before that was
resolved?

As far as I understand the patch will always introduce missed-optimization regressions for "artificial" testcases - it's just the way the patch is designed. I agree that the flipping half-range regression is the worst one and it does surely happen in real code. I don't know how far the RM was aware of these potential problems (after all I found out about them after the RMs approval of the backport). Still the backport is worth it, maybe with biting the bullet and disabling overflowed-infs for -fstrict-overflow and not -Wstrict-overflow.

Richard.


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