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Re: [tcb] Incremental SSA updates
Hello,
> > -- I had to disable lambda-code.c:perfect_nestify in case there are exit phi
> > nodes for the outer loop (this causes a regression -- ltrans1.c is no
> > longer optimized). The reason is that perfect_nestify behaves
> > wrong in this case -- it keeps the exit phi nodes in the original
> > loop, although some of the values may be defined in the part of the
> > code that was moved to the new loop, thus causing failures in
> > verify_ssa. Just moving the phi nodes to the exit of the new loop
> > is not right either (this fails in case the values are defined in the
> > inner loop).
> > I am not really sure whether I interpret the code
> > correctly, or why this does not fail without the patch; Daniel, could
> > you please have a look?
>
> I believe we went over this before. you aren't actually interpreting the
> code correctly, because that's not where the real bug is.
> The mark_for_rewrite call you removed was there to keep it from
> releasing the phi node names while we moved them. If you don't have it,
> it will simply release them when we remove the phi nodes from one block,
> and then they get reused, but are still referenced in the copies we
> moved, as well as wherever else they got reused, which is the real
> reason why you get verify_ssa failures.
no, I have solved this problem (I simply set PHI_RESULT of the removed
phi to NULL before releasing it). This is something entirely different.
Zdenek