[llvm] [MachineCP] Correctly handle register masks and sub-registers (PR #122472)

[Nikita Popov via llvm-commits]

nikic wrote:

I've reverted this in https://github.com/llvm/llvm-project/commit/d6f7f2a5fa0e305253f936cdc8364eecfd568121 because it causes a large compile-time regression, see https://llvm-compile-time-tracker.com/compare.php?from=d03f35f9b6d031d6a9375d90ccf7cc285f8e4b79&to=e2a071ece58790f8dd4886e998033cab82e906fb&stat=instructions:u. It should be possible to do this more efficiently.

https://github.com/llvm/llvm-project/pull/122472