Description of problem:

Clang supports (https://llvm.org/docs/HowToBuildWithPGO.html) bootstrapping with PGO. It increases Clang performance. The same thing is already enabled for GCC in Fedora (profiledbootstrap option). I think the same thing could be done for Clang since in the current build script I don't see that Clang is built with PGO.


Expected results:
Provided Clang binaries with Fedora are built with PGO.

Additional option:
Also you could try to build binary with LLVM BOLT (https://github.com/facebookincubator/BOLT/blob/main/bolt/docs/OptimizingClang.md) but I guess it's another question and it's much more complicated topic.