[llvm] [WebAssembly] Add fold support for dot (PR #151775)

[Luke Lau via llvm-commits]

https://github.com/lukel97 approved this pull request.

LGTM with the PR title updated

I think we can handle the zext from i8 case in a separate PR if the pattern ends up being somewhat different anyway, but I'll defer to @sparker-arm on this! (I'm not strongly opinionated on this as to if we want to do this as a combine or tablegen pattern)

https://github.com/llvm/llvm-project/pull/151775