[llvm] [X86][AMX] Check also AMX register live out for copy lowering (PR #93692)

[Nikita Popov via llvm-commits]

nikic wrote:

This causes a large compile-time regression: http://llvm-compile-time-tracker.com/compare.php?from=875e91131847e3133d414c11c8ad721b52a287ee&to=8aa33f16e91d8f15037330620c1479555278dafe&stat=instructions:u I think this is basically the same regression as the original implementation of https://github.com/llvm/llvm-project/pull/83628, because the LiveRegUnits usage is no longer guarded.

I'd recommend you to just revert the original PR and forget about it. This is typical fallout from an AtariDreams PR.

https://github.com/llvm/llvm-project/pull/93692