[llvm] [WebAssembly] Fold constant `i8x16.swizzle` and `i8x16.relaxed.swizzle` to `shufflevector` (PR #169110)

[Derek Schuff via llvm-commits]

dschuff wrote:

> I've updated the PR description. I also noticed that for most other targets (except AMDGPU and x86), the `instCombineIntrinsic` hook is _not_ a separate file, and is instead part of `[target]TargetTransformInfo.cpp`. Should I just move the new hook into `WebAssemblyTargetTransformInfo.cpp`?

I think that would be fine. Both WebAssemblyTargetTransformInfo.cpp and your addition are pretty small, whereas for e.g. X86 they are pretty big.



https://github.com/llvm/llvm-project/pull/169110