[all-commits] [llvm/llvm-project] b3cb95: [PGO]Implement metadata combine for 'branch_weight...

[Mingming Liu via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b3cb950cf3d162459a31a9ab533af0f403f344eb
      https://github.com/llvm/llvm-project/commit/b3cb950cf3d162459a31a9ab533af0f403f344eb
  Author: Mingming Liu <mingmingl at google.com>
  Date:   2023-04-27 (Thu, 27 Apr 2023)

  Changed paths:
    M llvm/include/llvm/IR/Metadata.h
    M llvm/lib/IR/Metadata.cpp
    M llvm/lib/Transforms/Utils/Local.cpp
    M llvm/test/Transforms/GVN/calls-readonly.ll
    A llvm/test/Transforms/SimplifyCFG/merge-direct-call-branch-weights-in-hoist.ll
    A llvm/test/Transforms/SimplifyCFG/merge-direct-call-branch-weights-in-sink.ll

  Log Message:
  -----------
  [PGO]Implement metadata combine for 'branch_weights' of direct
callsites when none of the instructions folds the rest away.

- Merge cases are added for simplify-cfg {sink,hoist}, based on https://gcc.godbolt.org/z/avGvc38W7 and https://gcc.godbolt.org/z/dbWbjGhaE
- When one instruction folds the others in, do not update branch_weights
  with sum (see test/Transforms/GVN/calls-readonly.ll)

Differential Revision: https://reviews.llvm.org/D148877