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Re: ifcvt/crossjump patch: Fix PR 42496, 21803
On Thu, Jul 29, 2010 at 6:19 PM, Paolo Bonzini <email@example.com> wrote:
> Second, crossjumping is now more expensive. ?Does it buy much really to
> iterate it? ?Something like
> ?mode &= ~CLEANUP_CROSSJUMP;
> just before iterating may still leave it "good enough". ?Steven, do you
> remember anything? ?This anyway can be done separately after the patch goes
Iterating is often helpful. Crossjumping only merges single pairs of
basic blocks per iteration, but never across a control flow statement.
If you iterate, you usually find that the previous iteration exposed
further opportunities. And crossjumping is not very expensive anyway.
I just hopes someone picks up the patches of PR20070 for pre-reload
crossjumping, that's even more helpful than iterating.