Index: lib/Transforms/Instrumentation/SanitizerCoverage.cpp
===================================================================
--- lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -31,7 +31,6 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Analysis/EHPersonalities.h"
-#include "llvm/Analysis/PostDominators.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/DataLayout.h"
@@ -169,7 +168,6 @@
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<DominatorTreeWrapperPass>();
-    AU.addRequired<PostDominatorTreeWrapperPass>();
   }
 
 private:
@@ -367,23 +365,8 @@
   return true;
 }
 
-// True if block has predecessors and it postdominates all of them.
-static bool isFullPostDominator(const BasicBlock *BB,
-                                const PostDominatorTree *PDT) {
-  if (pred_begin(BB) == pred_end(BB))
-    return false;
-
-  for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) {
-    if (!PDT->dominates(BB, PRED))
-      return false;
-  }
-
-  return true;
-}
-
 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB,
                                   const DominatorTree *DT,
-                                  const PostDominatorTree *PDT,
                                   const SanitizerCoverageOptions &Options) {
   // Don't insert coverage for unreachable blocks: we will never call
   // __sanitizer_cov() for them, so counting them in
@@ -401,7 +384,7 @@
   if (Options.NoPrune || &F.getEntryBlock() == BB)
     return true;
 
-  return !(isFullDominator(BB, DT) || isFullPostDominator(BB, PDT));
+  return !isFullDominator(BB, DT);
 }
 
 bool SanitizerCoverageModule::runOnFunction(Function &F) {
@@ -433,11 +416,9 @@
 
   const DominatorTree *DT =
       &getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
-  const PostDominatorTree *PDT =
-      &getAnalysis<PostDominatorTreeWrapperPass>(F).getPostDomTree();
 
   for (auto &BB : F) {
-    if (shouldInstrumentBlock(F, &BB, DT, PDT, Options))
+    if (shouldInstrumentBlock(F, &BB, DT, Options))
       BlocksToInstrument.push_back(&BB);
     for (auto &Inst : BB) {
       if (Options.IndirectCalls) {
@@ -719,7 +700,6 @@
                       "ModulePass",
                       false, false)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
 INITIALIZE_PASS_END(SanitizerCoverageModule, "sancov",
                     "SanitizerCoverage: TODO."
                     "ModulePass",
Index: test/Instrumentation/SanitizerCoverage/chains.ll
===================================================================
--- /dev/null
+++ test/Instrumentation/SanitizerCoverage/chains.ll
@@ -0,0 +1,27 @@
+; RUN: opt < %s -sancov -sanitizer-coverage-level=4 -sanitizer-coverage-trace-pc -sanitizer-coverage-prune-blocks=1  -S | FileCheck %s
+
+define i32 @blah(i32) #0 {
+  %2 = icmp sgt i32 %0, 1
+  br i1 %2, label %branch, label %exit
+; CHECK: call void @__sanitizer_cov_trace_pc()
+branch:
+  br label %pos2
+; CHECK-LABEL: branch:
+; CHECK-NOT: call void @__sanitizer_cov_trace_pc()
+pos2:
+  br label %pos3
+; CHECK-LABEL: pos2:
+; CHECK-NOT: call void @__sanitizer_cov_trace_pc()
+pos3:
+  br label %pos4
+; CHECK-LABEL: pos3:
+; CHECK-NOT: call void @__sanitizer_cov_trace_pc()
+pos4:
+  ret i32 0
+; CHECK-LABEL: pos4:
+; CHECK: call void @__sanitizer_cov_trace_pc()
+exit:
+  ret i32 0
+; CHECK-LABEL: exit:
+; CHECK: call void @__sanitizer_cov_trace_pc()
+}