Re: Haney's real matrix test regression

[kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)]

    For sure the "O-O C++" version performed better than the "hard coded C"
    version of the test case until a week ago, and this is the case indeed
    the case for gcc3.0.2.

Well, I'd say try again, since what we're seeing is C++-specific.

    You mean that your recent checkins, while improving the optimization
    of C code have a negative impact for C++ code until some radical
    modifications are implemented to improve C++ alias analysis?

My changes were not to improve optimization, but to fix bugs where the
wrong alias set was used.  I don't have any idea if a "radical modication"
of G++ is needed to allow using normal alias sets or not since I have
no idea why they have been disabled.  Hopefully, that's just a very
overly-conservative test that can be refined.  For example, as written,
it applies to all ARRAY_TYPEs, but the comment suggest it shouldn't.