[Dominators][CodeGen] Add MachinePostDominatorTree verification

Summary:
This patch implements Machine PostDominator Tree verification and ensures that the verification doesn't fail the in-tree tests.

MPDT verification can be enabled using `verify-machine-dom-info` -- the same flag used by Machine Dominator Tree verification.

Flipping the flag revealed that MachineSink falsely claimed to preserve CFG and MDT/MPDT. This patch fixes that.

Reviewers: arsenm, hliao, rampitec, vpykhtin, grosser

Reviewed By: hliao

Subscribers: wdng, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68235

llvm-svn: 373341

1 files changed, 0 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp
index 8f0d436..27a2e70 100644
--- a/llvm/lib/CodeGen/MachineSink.cpp
+++ b/llvm/lib/CodeGen/MachineSink.cpp
@@ -115,15 +115,12 @@ namespace {
     bool runOnMachineFunction(MachineFunction &MF) override;
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
-      AU.setPreservesCFG();
       MachineFunctionPass::getAnalysisUsage(AU);
       AU.addRequired<AAResultsWrapperPass>();
       AU.addRequired<MachineDominatorTree>();
       AU.addRequired<MachinePostDominatorTree>();
       AU.addRequired<MachineLoopInfo>();
       AU.addRequired<MachineBranchProbabilityInfo>();
-      AU.addPreserved<MachineDominatorTree>();
-      AU.addPreserved<MachinePostDominatorTree>();
       AU.addPreserved<MachineLoopInfo>();
       if (UseBlockFreqInfo)
         AU.addRequired<MachineBlockFrequencyInfo>();