Index: include/llvm/Analysis/PostDominators.h
===================================================================
--- include/llvm/Analysis/PostDominators.h
+++ include/llvm/Analysis/PostDominators.h
@@ -29,6 +29,8 @@
 class PostDominatorTree : public PostDomTreeBase<BasicBlock> {
 public:
   using Base = PostDomTreeBase<BasicBlock>;
+  PostDominatorTree() = default;
+  explicit PostDominatorTree(Function &F) { recalculate(F); }
 
   /// Handle invalidation explicitly.
   bool invalidate(Function &F, const PreservedAnalyses &PA,
Index: include/llvm/Transforms/Utils/BasicBlockUtils.h
===================================================================
--- include/llvm/Transforms/Utils/BasicBlockUtils.h
+++ include/llvm/Transforms/Utils/BasicBlockUtils.h
@@ -34,6 +34,7 @@
 class LoopInfo;
 class MDNode;
 class MemoryDependenceResults;
+class PostDominatorTree;
 class ReturnInst;
 class TargetLibraryInfo;
 class Value;
@@ -82,14 +83,16 @@
 /// during critical edge splitting.
 struct CriticalEdgeSplittingOptions {
   DominatorTree *DT;
+  PostDominatorTree *PDT;
   LoopInfo *LI;
   bool MergeIdenticalEdges = false;
   bool DontDeleteUselessPHIs = false;
   bool PreserveLCSSA = false;
 
   CriticalEdgeSplittingOptions(DominatorTree *DT = nullptr,
-                               LoopInfo *LI = nullptr)
-      : DT(DT), LI(LI) {}
+                               LoopInfo *LI = nullptr,
+                               PostDominatorTree *PDT = nullptr)
+    : DT(DT), PDT(PDT), LI(LI) {}
 
   CriticalEdgeSplittingOptions &setMergeIdenticalEdges() {
     MergeIdenticalEdges = true;
Index: lib/Transforms/Scalar/LinearizeCFG.cpp
===================================================================
--- lib/Transforms/Scalar/LinearizeCFG.cpp
+++ lib/Transforms/Scalar/LinearizeCFG.cpp
@@ -2605,7 +2605,7 @@
   SmallVector<BasicBlock *, 8> OrderedUnstructuredBlocks;
 
   // FIXME: PDT update
-  CriticalEdgeSplittingOptions CESO(DT);
+  CriticalEdgeSplittingOptions CESO(DT, nullptr, PDT);
   SplitAllCriticalEdges(*Func, CESO);
 
   //DenseSet<BasicBlock *> UnstructuredBlocks;
Index: lib/Transforms/Utils/BreakCriticalEdges.cpp
===================================================================
--- lib/Transforms/Utils/BreakCriticalEdges.cpp
+++ lib/Transforms/Utils/BreakCriticalEdges.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/PostDominators.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Instructions.h"
@@ -48,10 +49,14 @@
     bool runOnFunction(Function &F) override {
       auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
       auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
+
+      auto *PDTWP = getAnalysisIfAvailable<PostDominatorTreeWrapperPass>();
+      auto *PDT = PDTWP ? &PDTWP->getPostDomTree() : nullptr;
+
       auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
       auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
       unsigned N =
-          SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions(DT, LI));
+        SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions(DT, LI, PDT));
       NumBroken += N;
       return N > 0;
     }
@@ -197,11 +202,12 @@
 
   // If we have nothing to update, just return.
   auto *DT = Options.DT;
+  auto *PDT = Options.PDT;
   auto *LI = Options.LI;
-  if (!DT && !LI)
+  if (!DT && !PDT && !LI)
     return NewBB;
 
-  if (DT) {
+  if (DT || PDT) {
     // Update the DominatorTree.
     //       ---> NewBB -----\
     //      /                 V
@@ -217,7 +223,10 @@
     if (llvm::find(successors(TIBB), DestBB) == succ_end(TIBB))
       Updates.push_back({DominatorTree::Delete, TIBB, DestBB});
 
-    DT->applyUpdates(Updates);
+    if (DT)
+      DT->applyUpdates(Updates);
+    if (PDT)
+      PDT->applyUpdates(Updates);
   }
 
   // Update LoopInfo if it is around.
Index: unittests/Transforms/Utils/BasicBlockUtils.cpp
===================================================================
--- unittests/Transforms/Utils/BasicBlockUtils.cpp
+++ unittests/Transforms/Utils/BasicBlockUtils.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Analysis/PostDominators.h"
 #include "llvm/AsmParser/Parser.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Dominators.h"
@@ -50,3 +51,31 @@
   SplitBlockPredecessors(&F->getEntryBlock(), {}, "split.entry", &DT);
   EXPECT_TRUE(DT.verify());
 }
+
+TEST(BasicBlockUtils, SplitCriticalEdge) {
+  LLVMContext C;
+
+  std::unique_ptr<Module> M = parseIR(
+    C,
+    "define void @crit_edge(i1 %cond0, i1 %cond1) {\n"
+    "entry:\n"
+    "  br i1 %cond0, label %bb0, label %bb1\n"
+    "bb0:\n"
+    "  br label %bb1\n"
+    "bb1:\n"
+    "  br label %bb2\n"
+    "bb2:\n"
+    "  ret void\n"
+    "}\n"
+    "\n"
+    );
+
+  auto *F = M->getFunction("crit_edge");
+  DominatorTree DT(*F);
+  PostDominatorTree PDT(*F);
+
+  CriticalEdgeSplittingOptions CESO(&DT, nullptr, &PDT);
+  EXPECT_EQ(1u, SplitAllCriticalEdges(*F, CESO));
+  EXPECT_TRUE(DT.verify());
+  EXPECT_TRUE(PDT.verify());
+}