[PATCH] D21405: [PGO] IRPGO pre-cleanup pass changes

[Rong Xu via llvm-commits]

xur added a comment.

This cleanup passes also have performance impact on the profile-use compilation.

In google benchmarks, compare to without these cleanup passes, we are seeing  ~14% improvement for 1 benchmark, ~2 to ~4% for 3 benchmarks, and ~1% for other 2 benchmarks.

If we run these cleanup passes on O2 (without fdo), we only see small improvement (~1%) on 2 benchmarks.
We are thinking a large part of the improvement in profile-use is getting from better context sensitive profiles.

Note that all the numbers are got from existing profile-use infrastructure which is less well tuned.


http://reviews.llvm.org/D21405