[all-commits] [llvm/llvm-project] 913837: [ScheduleDAG] Fix removing edges with weak deps

[Austin Kerbow via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 913837eaa3d14a5fb68179f8210dc097383a048c
      https://github.com/llvm/llvm-project/commit/913837eaa3d14a5fb68179f8210dc097383a048c
  Author: Austin Kerbow <Austin.Kerbow at amd.com>
  Date:   2023-01-25 (Wed, 25 Jan 2023)

  Changed paths:
    M llvm/lib/CodeGen/ScheduleDAG.cpp
    A llvm/test/CodeGen/AMDGPU/sched-barrier-hang-weak-dep.mir

  Log Message:
  -----------
  [ScheduleDAG] Fix removing edges with weak deps

In SUnit::removePred edges are removed from the Preds and Succs lists before
updating the bookkeeping. This could result in incorrect values for
NumPreds/SuccsLeft and cause WeakPreds/SuccsLeft to underflow, since the
incorrect SDep will be used to update these values.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D142325