[llvm] [CodeGen] Don't include aliases in RegisterClassInfo::IgnoreCSRForAllocOrder (PR #80015)

[Nikita Popov via llvm-commits]

nikic wrote:

It looks like this approach is faster on AMDGPU, but slower on more conventional architectures: http://llvm-compile-time-tracker.com/compare.php?from=db49319264d6d2b6f9f7b345495d543210c2cfe3&to=f8525030004f907cd108e7c18df255a6d3b23124&stat=instructions:u

https://github.com/llvm/llvm-project/pull/80015