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Re: Introducing redundancy in combine?
On Mon, Jun 21, 2010 at 17:21, Jeff Law <law@redhat.com> wrote:
> Ouch. ?You've got another problem in that combine doesn't combine across
> basic blocks.
Actually tree-if-conversion does take care of transforming the inner loop
into one BB to enable vectorization. So we don't have the cross-BB
combine problem.
> Can you attack it in forwprop?
>
I'll give it a look.
> I'm a little surprised DOM removed the multiplication -- it's not actually a
> runtime redundancy, it's more like a code hoisting since on any given
> iteration of the loop the expression level * qmul is only evaluated once.
Right, I am pretty sure DOM does this transform.
Sebastian