[llvm] [WebAssembly] Implement getInterleavedMemoryOpCost (PR #146864)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

Looks like `llvm/test/Transforms/LoopVectorize/WebAssembly/memory-interleave.ll` started failing recently, possibly related to this PR?

https://github.com/llvm/llvm-project/pull/146864