[PATCH] D95373: Replace vector intrinsics with call to vector library

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D95373#2520409 <https://reviews.llvm.org/D95373#2520409>, @LukasSommerTu wrote:

> @lebedev.ri: Thanks for your feedback!
>
> My reasoning to implement this as an IR pass was that the replacement for the scalar version of the intrinsics is also happening as part of the middle-end, so it made sense to me to implement this in a similar location and use similar mechansisms.

Hm, it does? That seems quite surprising to me.

> My motivating usage scenario was to add this pass to the pipeline that is applied after converting from MLIR to LLVM IR, which introduces these calls. As the replacement requires some target-specific information (TargetLibraryInfo), implementing it on the LLVM side rather than in MLIR seemed reasonable to me. If other frontends produce similar IR, they can also benefit from this pass/transformation.

The thing is, the passes that now know how to deal with whatever IR instruction/intrinsic,
will now need to also know about N flavors of those intrinsics shaped in the form of a libcall.
This doesn't quite seem like the right direction.
Also, tangentially related, is there cost modelling being performed for them?

So i would still expect this to happen somewhere in codegen (`llc`) pipeline, not optimization (`opt`) pipeline..


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https://reviews.llvm.org/D95373