Here I will introduce my idea of a inliner that can handle splitting cold edge as well:
My idea is to use the inlined function, but inline from the uninlined function.
- Do normal optimizations without inlining
- Split the cold edges into other functions
- Copy each function @xyz to @xyz.i (or other name that does not clash) and mark @xyz with ‘inlines @xyz.i’
==> this needs an identifier to mark the shadow function for each function
All other operations are performed on @xyz. @xyz.i will contain the uninlined version
- Each function @xyz can now inline its contained functions @abc while you don’t inline @abc directly, but @abc.i
- When a function @xyz becomes shorter than @xyz.i, the inline remark and the non-inlined
- After everything is inlined, new cold edges can appear. They can now be split again. New optimizations are possible.
- Functions that call functions containing these cold edges can now inline them. These functions can be optimized again.
Example: (function signatures in LLVM, content in PSEUDO-Code)