Evaluate using Profile-Guided Optimization (PGO) for the project

[zamazan4ik]

Hi!

I evaluated one specific compiler optimization - Profile-Guided Optimization (aka PGO) on multiple projects (compilers, databases, parsers, etc.) and programming languages. All the results are available in my repository - https://github.com/zamazan4ik/awesome-pgo . I think there are several ideas of how PGO integration can be useful for C3C.

• Optimize the c3c compiler itself with PGO. PGO is already supported in all major C compilers. Since this, it's possible to optimize the compiler itself with PGO and improve the compiler performance for users. I have multiple benchmarks when clang and gcc compilers improved by 10-15% in compilation time by applying PGO.
• Integrate an ability to optimize C3C programs themself with PGO. It will allow users to optimize their programs with this optimization. However, even if the compiler uses LLVM (LLVM supports PGO primitives very well), it requires some work to be done on the compiler.

I hope these ideas will be interesting for someone.

Thank you!