[llvm] [TTI][WebAssembly] Pairwise reduction expansion (PR #93948)

[Sam Parker via llvm-commits]

sparker-arm wrote:

> Do we need to check for ordered float reductions?

If I understand the question correctly, we already do. ExpandReductions will only generate a shuffle for operations that allow reassociation and this is when we can choose our arbitrary shuffle pattern(s).

https://github.com/llvm/llvm-project/pull/93948