Re: C++ PATCH: multiple inheritance optimization

[Mark Mitchell <mark at codesourcery dot com>]

>>>>> "Jeffrey" == Jeffrey A Law <law@cygnus.com> writes:

    Jeffrey>   In message
    Jeffrey> <20000117185231O.mitchell@codesourcery.com>you write:
    >> But, I'd be more motivated, actually, to figure out how to make
    >> GCSE handle these kinds of things correctly.  Even if we solve
    >> *this* one, this bit of converting to bases happens a lot, and
    >> it would be much better if the back-end could be taught to
    >> handle it.

    Jeffrey> FYI -- gcse is basically does nothing on the x86 right
    Jeffrey> now because gcse.c doesn't know how to deal with hard
    Jeffrey> registers.  So all those patterns that do something like

    Jeffrey> 	(clobber (reg;CC 17))

    Jeffrey> Will tend to inhibit most optimizations done by gcse.

Right -- that's what Richard indicated earlier.  He wasn't sure if the
reason GCSE doesn't handle hard registers was just that y'all weren't
sure it would work -- or if there was a known reason why it would not
work.

--
Mark Mitchell                   mark@codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com