Explore overlap between PCM & LLVM project

[nealsid]

I think it would be neat to develop some sort of compiler intrinsics that depend on PCM to be able to measure performance counters in a section of code, similar to macOS's signposts, but implemented in the compiler (perhaps some work would be necessary since PCM is Intel-specific, too). I worked with someone on LLVM earlier this year and I may be able to touch base with them to explore whether this could be an interesting path to think about. Thank you.