[clang] [compiler-rt] [llvm] [PGO][AMDGPU] Add uniformity-aware offload profile format and instrumentation (PR #190708)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

gentle ping. rebased to tot of main as the PR for basic HIP device PGO has been merged.

https://github.com/llvm/llvm-project/pull/190708