[PATCH] D49040: [SLC] Simplify pow(x, 0.333...) to cbrt(x)

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

As we discussed in https://reviews.llvm.org/D49306, I agree that this is probably a good perf transform, but I don't think we've shown any compelling reason to do this in IR vs. DAGCombiner.

There are downsides to doing this in IR currently because we don't have a cbrt intrinsic. That means we have different behavior based on data type (vectors won't get transformed).
It's also not clear why transforming to a form with fdiv in the negative exponent case is better than a single pow instruction. (And that case probably needs some perf justification even as a backend fold.)


https://reviews.llvm.org/D49040