Introducing redundancy in combine?

[Sebastian Pop]

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