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Re: Patch ping ^ 2
Hello,
> > this patch fixes (at least) two several serious problems in lim store
> > motion -- misscompilations (PR 17133 and several duplicates) and
> > problems with compile time (PR 17790).
> >
> > http://gcc.gnu.org/ml/gcc-patches/2004-09/msg01120.html
>
> I still have serious problems with this patch.
> It simply drops using the SSA form to do store motion, and relies on
> variable names and lack of aliasing to decide what to move.
could you please explain more precisely what you mean by the last two
points? If "relies on variable names" means that it ignores ssa
versions for virtual operands, yes, it does, since virtual operands are
in FUD form, so their ssa versions do not carry any interesting
information (if you do not use them to traverse UD chains, which does
not make much sense in case you need to scan body of the whole loop
anyway). I have no idea what you mean by "relies on ... lack of
aliasing".
Zdenek