[Bug rtl-optimization/43892] PowerPC suboptimal "add with carry" optimization

[joakim dot tjernlund at transmode dot se]

------- Comment #6 from joakim dot tjernlund at transmode dot se  2010-04-26 15:18 -------
Subject: Re:  PowerPC suboptimal "add with carry" optimization


"rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> wrote on 2010/04/26
16:43:04:
> > Will that also address the loop optimization? I don't think so.
>
> No.

OK, would be nice if the loop case could be fixed too.

Just noticed this too:
add32carry:
        add 3,3,4
        subfc 0,4,3
        subfe 0,0,0
        subfc 0,0,3
        mr 3,0

That could have been better even without "add with carry" optimization:
add32carry:
        add 3,3,4
        subfc 0,4,3
        subfe 0,0,0
        subfc 3,0,3


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43892