[PATCH] D27919: [Loop Vectorizer] Interleave vs Gather - in some cases Gather is better.

Matthew Simpson via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Jan 17 11:42:22 PST 2017

mssimpso added a comment.

In https://reviews.llvm.org/D27919#647975, @delena wrote:

> I'm trying to revisit collections of Uniforms and Scalars after cost estimation and remove GEPs and induction variables if we decided to scalarize. Not finished yet..

That sounds like a good idea to me, and I hope we can separate the uniform/scalar collection from the cost estimation in a way that makes sense. When I looked at doing that a while back, the complication I ran into was that the cost estimates depend on knowing the uniforms. But if we use the cost estimates to help determine the uniforms, then we end up with a weird circular dependence. If we mark something uniform/scalar after computing the costs, we will need to update the costs somehow. That in turn might change what we would like to scalarize, etc.



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