[PATCH] D32563: Improve code placement algorithm in Reassociate pass.

[Wei Mi via llvm-commits]

On Thu, Apr 27, 2017 at 1:26 PM, Daniel Berlin via Phabricator
<reviews at reviews.llvm.org> wrote:
> dberlin added a comment.
>
> Isn't this close to what n-ary reassociate does?
> (if so, why not just use that and disable this?)
>

Nary reassociate tries to maximize the redundency exposed by
reassociation. This patch tries to reduce the register pressure by
changing where to insert the intermediate results of reassociation,
and it doesn't try to improve the result of reassociation for better
CSE/PRE/LICM optimizations. The two have different motivations, so I
don't see how nary reassociation can be helpful here.

>
> https://reviews.llvm.org/D32563
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