[clang] [llvm] [PromoteMemToReg] Insert store undef when removing lifetime markers (PR #191909)

[Aiden Grossman via cfe-commits]

https://github.com/boomanaiden154 commented:

The HLSL clang fix should be done as a separate PR and ideally should have some test coverage.

https://github.com/llvm/llvm-project/pull/191909