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Re: Serious performance regression -- some tree optimizer questions




On Wed, 12 Jan 2005, Daniel Berlin wrote:



On Wed, 12 Jan 2005, Ulrich Weigand wrote:

Daniel Berlin <dberlin@dberlin.org> wrote on 12/20/2004 01:25:49 AM:

If you find it helps other testcases, or whatever, i'm happy to try to
explore making that patch usable.

OK, the current situation w.r.t. mgrid is as follows:


With unmodified GCC, mgrid on 31-bit generates bad code due to a
combination of the problem fixed by your patch and IV selection
issues.  On 64-bit, the problem addressed by your patch doesn't
occur, but we have problems due to IV sign-extension (and also
IV selection issues).

Ivopts is become large.
<...>

Even with all of these caveats, however, i should note that i still believe the various patches to fix these performance regressions very much need to be considered for 4.0.


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