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

[Craig Topper via llvm-commits]

topperc wrote:

> In my opinion matching target-specific opcodes is a hack, and we should want to fix this for GISel by matching the generic opcode. No idea if the importer can handle this though.

I don't follow. SelectionDAG is turning ISD::SPLAT_VECTOR into RISCVISD::VMV_V_X_VL or RISCVISD::VFMV_V_X_VL. We're never matching selected opcodes.

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