[PATCH] D53598: Add docs+a script for building clang/LLVM with PGO

[Shoaib Meenai via Phabricator via llvm-commits]

smeenai added a comment.

I notice that you're using `LLVM_BUILD_INSTRUMENTED=IR`, which corresponds to `-fprofile-generate` (IR-level profiling), instead of `-fprofile-instr-generate` (clang-level profiling). Did you play around with both and observe that IR-level profiling gave you better results?

Btw, I tried this out and got a 20% improvement on a self-host with PGO, which is pretty handy :)


Repository:
  rL LLVM

https://reviews.llvm.org/D53598