[llvm] [RegisterCoalescer] Skip CR_Replace pattern that has early-clobber in segment's edge (PR #71024)

[Piyou Chen via llvm-commits]

BeMg wrote:

> Does that mean you encounter generic `COPY` or `SUBREG_TO_REG` instructions with an early-clobber destination (the coalescer only handles instructions with `MachineInstr::isCopyLike()` no?) ? Is that intentional? My first instinct would we be to just not allow early-clobber flags for these generic opcodes...

The `early-clobber` comes from the RISC-V pseudo `PseudoVRGATHER_VI_M1`. And all VReg coalescing is triggered by `COPY` without early-clobber itself.



https://github.com/llvm/llvm-project/pull/71024