[llvm] SPIRV: Set NoPHIs property after selection (PR #136327)

[Vyacheslav Levytskyy via llvm-commits]

VyacheslavLevytskyy wrote:

@arsenm  We currently do not select OpPhi during the instruction selection pass, instead we keep PHI until the module layout finalization stage (introduced as one of improvements in https://github.com/llvm/llvm-project/pull/119202 -- https://github.com/VyacheslavLevytskyy/llvm-project/blob/3e74d2c6983af986b70060ca44e6e1fbcb34a554/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp#L3354-L3369).

https://github.com/llvm/llvm-project/pull/136327