[PATCH] D43427: [RegAllocFast] Salvage debug values when killing operands

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added a comment.

- I'd rather keep MachineRegisterInfo to things directly related to information about virtual registers (register class etc.); I don't think it's role should be to provide transformations for involving virtual registers. So I'd rather move the functionality somewhere else.
- I'm skeptical this works as intended in the presence of control flow (= multiple uses and defs of a vreg anywhere in the control flow graph).
- I'm not sure I completely understand what is going on here, is it looking for COPYs killing a value so it can replace the debug values with the copied value? The commit message should mention that then.


https://reviews.llvm.org/D43427