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Re: SSA for Trees - PRE implementation
On Thu, 2004-01-08 at 14:47, Daniel Berlin wrote:
> > I guess the real question is ... Do
> > you see it eventually replacing the either existing PRE pass?
> >
> Not unless we don't produce any partially redundant expressions in the
> backend.
I assumed that the new SSA PRE would supplant the existing PRE passes.
>From your reply, i gather that, instead, it will be in addition to the
existing passes. I understand why.
However, it seems that the new SSA PRE would be somewhat redundant as
most of the evaluations it removes would be removed by lazy code motion
or Morel-Renvoise PRE. In my work, the SSA implementation was no more
powerful than LCM, just more difficult to implement. Are you finding
that the additional SSA PRE is worthwhile?
Sid