[llvm] [RISCV][GISEL] instruction-select for G_SPLAT_VECTOR (PR #111193)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

I reserve the right to ask stupid questions. Why are you building G_X instructions in the RISC-V instruction selector? Why bother with target independent instructions in the RISC-V selector. You know how the select a G_CONSTANT. Instead of building a G_CONSTANT, can't you just invoke let's say selectRISCVIConstant();

It should be an anti-pattern to build G_X instructions in selectors. You run in legality issues again.

https://github.com/llvm/llvm-project/pull/111193