[llvm] [AMDGPU] Added hot-block-rematerialize pass (PR #126331)

[Jay Foad via llvm-commits]

jayfoad wrote:

Hi @adam-yang, I've done some testing with this patch and noticed that options `-amdgpu-remat-enable-hot-block-remat-aggressive` and `-amdgpu-remat-enable-sub-exp-remat` seem to cause many crashes in the compiler. Are you interested in test cases for these? Or are these options not expected to be working yet?

https://github.com/llvm/llvm-project/pull/126331