[llvm] [AMDGPU][AsmParser]: Use dummy operand for parsing buffer_ SWZ operand. (PR #165305)

[Jeffrey Byrnes via llvm-commits]

jrbyrnes wrote:

> I assume this is related to recently reported llvm-mca crash.

Yes, llvm-mca assumes each operand counted by MCInstrDesc numOperands will be in MCInst.operands. By not parsing a dummy for the SWZ, we violate this assumption and llvm-mca fails.

https://github.com/llvm/llvm-project/pull/165305