[PATCH] D66095: [InstCombine] canonicalize a scalar-select-of-vectors to vector select

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D66095#1627455 <https://reviews.llvm.org/D66095#1627455>, @lebedev.ri wrote:

> I'm honestly not sure here if i would consider splat-of-i1 or i1 more canonical,
>  i would kind-of guessed i1 since it is a single bit while vector isn't.


Yes, I can see that argument. However, if we consider the i1 canonical, then we need to reverse this patch + add the codegen fixup + make sure that IR transforms based on vector splat patterns can match that potential variation of the pattern. That seems like a lot more work than what we have here: try to convert a select with vector true/false operands to also have a vector condition because we know that plays nicely with vector code in general.


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