[JT] Preserve exisiting BPI/BFI during JumpThreading
authorEvgeniy Brevnov <ybrevnov@azul.com>
Wed, 26 Oct 2022 09:03:25 +0000 (16:03 +0700)
committerEvgeniy Brevnov <ybrevnov@azul.com>
Thu, 17 Nov 2022 10:00:00 +0000 (17:00 +0700)
commit52a4018506e39f50d0c06ac5a1c987eb83b900c7
tree345aea100e75b939087d85121c5a121c54d0a563
parent6393d2ea24fb458c353f8d453ab5f20663875cb1
[JT] Preserve exisiting BPI/BFI during JumpThreading

Currently, JT creates and updates local instances of BPI\BFI. As a result global ones have to be invalidated if JT made any changes.
In fact, JT doesn't use any information from BPI/BFI for the sake of the transformation itself. It only creates BPI/BFI to keep them up to date. But since it updates local copies (besides cases when it updates profile metadata) it just waste of time.

Current patch is a rework of D124439. D124439 makes one step and replaces local copies with global ones retrieved through AnalysisPassManager. Here we do one more step and don't create BPI/BFI if the only reason of creation is to keep BPI/BFI up to date. Overall logic is the following. If there is cached BPI/BFI then update it along the transformations. If there is no existing BPI/BFI, then create it only if it is required to update profile metadata.

Please note if BPI/BFI exists on exit from JT (either cached or created) it is always up to date and no reason to invalidate it.

Differential Revision: https://reviews.llvm.org/D136827
llvm/include/llvm/Transforms/Scalar/JumpThreading.h
llvm/lib/Transforms/Scalar/JumpThreading.cpp
llvm/test/Transforms/JumpThreading/thread-prob-2.ll
llvm/test/Transforms/JumpThreading/thread-prob-3.ll
llvm/test/Transforms/JumpThreading/thread-prob-4.ll
llvm/test/Transforms/JumpThreading/thread-prob-5.ll
llvm/test/Transforms/JumpThreading/thread-prob-6.ll
llvm/test/Transforms/JumpThreading/threading_prof1.ll
llvm/test/Transforms/JumpThreading/threading_prof2.ll
llvm/test/Transforms/JumpThreading/threading_prof3.ll