[llvm] [CodeGen] Speed up instruction insertion with debug info (NFCI) (PR #218373)

[Nikita Popov via llvm-commits]

nikic wrote:

Not seeing any compile-time impact from this in practice: https://llvm-compile-time-tracker.com/compare.php?from=519f6c146e4318ba96746432ae7fd428ae64acfc&to=2411a24c3f599e9e26e9c6abe1ff4d92c0d5174c&stat=instructions:u

https://github.com/llvm/llvm-project/pull/218373