Index: include/llvm/Transforms/Utils/Local.h
===================================================================
--- include/llvm/Transforms/Utils/Local.h
+++ include/llvm/Transforms/Utils/Local.h
@@ -291,6 +291,10 @@
 /// the given edge.  Returns the number of replacements made.
 unsigned replaceDominatedUsesWith(Value *From, Value *To, DominatorTree &DT,
                                   const BasicBlockEdge &Edge);
+/// \brief Replace each use of 'From' with 'To' if that use is dominated by
+/// the given BasicBlock. Returns the number of replacements made.
+unsigned replaceDominatedUsesWith(Value *From, Value *To, DominatorTree &DT,
+                                  const BasicBlock *BB);
 } // End llvm namespace
 
 #endif
Index: lib/IR/Dominators.cpp
===================================================================
--- lib/IR/Dominators.cpp
+++ lib/IR/Dominators.cpp
@@ -147,7 +147,8 @@
   // Assert that we have a single edge. We could handle them by simply
   // returning false, but since isSingleEdge is linear on the number of
   // edges, the callers can normally handle them more efficiently.
-  assert(BBE.isSingleEdge());
+  assert(BBE.isSingleEdge() &&
+         "This function is not efficient in handling multiple edges");
 
   // If the BB the edge ends in doesn't dominate the use BB, then the
   // edge also doesn't.
@@ -197,7 +198,8 @@
   // Assert that we have a single edge. We could handle them by simply
   // returning false, but since isSingleEdge is linear on the number of
   // edges, the callers can normally handle them more efficiently.
-  assert(BBE.isSingleEdge());
+  assert(BBE.isSingleEdge() &&
+         "This function is not efficient in handling multiple edges");
 
   Instruction *UserInst = cast<Instruction>(U.getUser());
   // A PHI in the end of the edge is dominated by it.
Index: lib/Transforms/Scalar/GVN.cpp
===================================================================
--- lib/Transforms/Scalar/GVN.cpp
+++ lib/Transforms/Scalar/GVN.cpp
@@ -725,7 +725,8 @@
     bool splitCriticalEdges();
     BasicBlock *splitCriticalEdges(BasicBlock *Pred, BasicBlock *Succ);
     bool replaceOperandsWithConsts(Instruction *I) const;
-    bool propagateEquality(Value *LHS, Value *RHS, const BasicBlockEdge &Root);
+    bool propagateEquality(Value *LHS, Value *RHS, const BasicBlockEdge &Root,
+                           bool DominatesByEdge);
     bool processFoldableCondBr(BranchInst *BI);
     void addDeadBlock(BasicBlock *BB);
     void assignValNumForDeadCode();
@@ -1777,7 +1778,7 @@
 
     // This property is only true in dominated successors, propagateEquality
     // will check dominance for us.
-    Changed |= propagateEquality(V, True, Edge);
+    Changed |= propagateEquality(V, True, Edge, false);
   }
 
   if (auto *CmpI = dyn_cast<CmpInst>(V)) {
@@ -2088,8 +2089,9 @@
 /// The given values are known to be equal in every block
 /// dominated by 'Root'.  Exploit this, for example by replacing 'LHS' with
 /// 'RHS' everywhere in the scope.  Returns whether a change was made.
-bool GVN::propagateEquality(Value *LHS, Value *RHS,
-                            const BasicBlockEdge &Root) {
+/// If DominatesByEdge is false, then it means that it is dominated by Root.End.
+bool GVN::propagateEquality(Value *LHS, Value *RHS, const BasicBlockEdge &Root,
+                            bool DominatesByEdge) {
   SmallVector<std::pair<Value*, Value*>, 4> Worklist;
   Worklist.push_back(std::make_pair(LHS, RHS));
   bool Changed = false;
@@ -2146,7 +2148,11 @@
     // LHS always has at least one use that is not dominated by Root, this will
     // never do anything if LHS has only one use.
     if (!LHS->hasOneUse()) {
-      unsigned NumReplacements = replaceDominatedUsesWith(LHS, RHS, *DT, Root);
+      unsigned NumReplacements =
+          DominatesByEdge
+              ? replaceDominatedUsesWith(LHS, RHS, *DT, Root)
+              : replaceDominatedUsesWith(LHS, RHS, *DT, Root.getEnd());
+
       Changed |= NumReplacements > 0;
       NumGVNEqProp += NumReplacements;
     }
@@ -2218,7 +2224,10 @@
         Value *NotCmp = findLeader(Root.getEnd(), Num);
         if (NotCmp && isa<Instruction>(NotCmp)) {
           unsigned NumReplacements =
-            replaceDominatedUsesWith(NotCmp, NotVal, *DT, Root);
+              DominatesByEdge
+                  ? replaceDominatedUsesWith(NotCmp, NotVal, *DT, Root)
+                  : replaceDominatedUsesWith(NotCmp, NotVal, *DT,
+                                             Root.getEnd());
           Changed |= NumReplacements > 0;
           NumGVNEqProp += NumReplacements;
         }
@@ -2292,11 +2301,11 @@
 
     Value *TrueVal = ConstantInt::getTrue(TrueSucc->getContext());
     BasicBlockEdge TrueE(Parent, TrueSucc);
-    Changed |= propagateEquality(BranchCond, TrueVal, TrueE);
+    Changed |= propagateEquality(BranchCond, TrueVal, TrueE, true);
 
     Value *FalseVal = ConstantInt::getFalse(FalseSucc->getContext());
     BasicBlockEdge FalseE(Parent, FalseSucc);
-    Changed |= propagateEquality(BranchCond, FalseVal, FalseE);
+    Changed |= propagateEquality(BranchCond, FalseVal, FalseE, true);
 
     return Changed;
   }
@@ -2318,7 +2327,7 @@
       // If there is only a single edge, propagate the case value into it.
       if (SwitchEdges.lookup(Dst) == 1) {
         BasicBlockEdge E(Parent, Dst);
-        Changed |= propagateEquality(SwitchCond, i.getCaseValue(), E);
+        Changed |= propagateEquality(SwitchCond, i.getCaseValue(), E, true);
       }
     }
     return Changed;
Index: lib/Transforms/Utils/Local.cpp
===================================================================
--- lib/Transforms/Utils/Local.cpp
+++ lib/Transforms/Utils/Local.cpp
@@ -1349,3 +1349,23 @@
   }
   return Count;
 }
+
+unsigned llvm::replaceDominatedUsesWith(Value *From, Value *To,
+                                        DominatorTree &DT,
+                                        const BasicBlock *BB) {
+  assert(From->getType() == To->getType());
+
+  unsigned Count = 0;
+  for (Value::use_iterator UI = From->use_begin(), UE = From->use_end();
+       UI != UE;) {
+    Use &U = *UI++;
+    auto *I = cast<Instruction>(U.getUser());
+    if (DT.dominates(BB, I->getParent())) {
+      U.set(To);
+      DEBUG(dbgs() << "Replace dominated use of '" << From->getName() << "' as "
+                   << *To << " in " << *U << "\n");
+      ++Count;
+    }
+  }
+  return Count;
+}