[llvm] [RISCV][GlobalISel] Legalize G_ADD, G_SUB, G_AND, G_OR, G_XOR on RISC-V Vector Extension (PR #71400)

[Craig Topper via llvm-commits]

topperc wrote:

> > What's your insight into this behavior and what's your opinion on implementation @michaelmaitland @topperc ? I mean using them in-place works, but it's clumsy.
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> I experienced this too when I was playing around. Maybe we should do the in place definition, and a future patch can allow `legalIf`, `legalFor` , etc to be overloaded with something like T[].

Does `auto AllVecTys = {` work? The documentation for initializer list calls out auto as being special for C++17.

https://github.com/llvm/llvm-project/pull/71400