[clang-tools-extra] [llvm] [clang] Add out-of-line-atomics support to GlobalISel (PR #74588)

[Matt Arsenault via cfe-commits]

arsenm wrote:

> > > // At -O0, fast-regalloc cannot cope with the live vregs necessary to
> > 
> > 
> > This sounds extremely unsound
> 
> Just to clarify, is the expectation for me to solve this in this patch or can this be done in a separate patch?

This should be separate, it's an unrelated issue

https://github.com/llvm/llvm-project/pull/74588