diff --git a/include/llvm/Transforms/Utils/SimplifyLibCalls.h b/include/llvm/Transforms/Utils/SimplifyLibCalls.h
index d2f096fd1ef..fb3beb2ab2d 100644
--- a/include/llvm/Transforms/Utils/SimplifyLibCalls.h
+++ b/include/llvm/Transforms/Utils/SimplifyLibCalls.h
@@ -71,12 +71,21 @@ private:
   const DataLayout *DL;
   const TargetLibraryInfo *TLI;
   bool UnsafeFPShrink;
+  function_ref<void(Instruction *, Value *)> Replacer;
 
-protected:
-  ~LibCallSimplifier() {}
+  /// \brief Internal wrapper for RAUW that is the default implementation.
+  ///
+  /// Other users may provide an alternate function with this signature instead
+  /// of this one.
+  static void replaceAllUsesWithDefault(Instruction *I, Value *With);
+
+  /// \brief Replace an instruction's uses with a value using our replacer.
+  void replaceAllUsesWith(Instruction *I, Value *With);
 
 public:
-  LibCallSimplifier(const DataLayout *TD, const TargetLibraryInfo *TLI);
+  LibCallSimplifier(const DataLayout *TD, const TargetLibraryInfo *TLI,
+                    function_ref<void(Instruction *, Value *)> Replacer =
+                        &replaceAllUsesWithDefault);
 
   /// optimizeCall - Take the given call instruction and return a more
   /// optimal value to replace the instruction with or 0 if a more
@@ -87,11 +96,6 @@ public:
   /// The call must not be an indirect call.
   Value *optimizeCall(CallInst *CI);
 
-  /// replaceAllUsesWith - This method is used when the library call
-  /// simplifier needs to replace instructions other than the library
-  /// call being modified.
-  virtual void replaceAllUsesWith(Instruction *I, Value *With) const;
-
 private:
   // String and Memory Library Call Optimizations
   Value *optimizeStrCat(CallInst *CI, IRBuilder<> &B);
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index a012be0669a..33f024b2729 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2919,25 +2919,6 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
   return MadeIRChange;
 }
 
-namespace {
-class InstCombinerLibCallSimplifier final : public LibCallSimplifier {
-  InstCombiner *IC;
-public:
-  InstCombinerLibCallSimplifier(const DataLayout *DL,
-                                const TargetLibraryInfo *TLI,
-                                InstCombiner *IC)
-    : LibCallSimplifier(DL, TLI) {
-    this->IC = IC;
-  }
-
-  /// replaceAllUsesWith - override so that instruction replacement
-  /// can be defined in terms of the instruction combiner framework.
-  void replaceAllUsesWith(Instruction *I, Value *With) const override {
-    IC->ReplaceInstUsesWith(*I, With);
-  }
-};
-}
-
 // FIXME: Passing all of the analyses here in the run method is ugly. We should
 // separate out the worklist from the combiner so that we can construct
 // a combiner once per function while re-using the storage of an external
@@ -2962,7 +2943,10 @@ bool InstCombiner::run(Function &F, AssumptionCache *AC, const DataLayout *DL,
       F.getContext(), TargetFolder(DL), InstCombineIRInserter(Worklist, AC));
   Builder = &TheBuilder;
 
-  InstCombinerLibCallSimplifier TheSimplifier(DL, TLI, this);
+  auto InstCombineRAUW = [this](Instruction *From, Value *With) {
+    ReplaceInstUsesWith(*From, With);
+  };
+  LibCallSimplifier TheSimplifier(DL, TLI, InstCombineRAUW);
   Simplifier = &TheSimplifier;
 
   bool EverMadeChange = false;
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 76d5cc4917d..13c2365e1ef 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -2084,15 +2084,19 @@ Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
   return nullptr;
 }
 
-LibCallSimplifier::LibCallSimplifier(const DataLayout *DL,
-                                     const TargetLibraryInfo *TLI) :
-                                     FortifiedSimplifier(DL, TLI),
-                                     DL(DL),
-                                     TLI(TLI),
-                                     UnsafeFPShrink(false) {
+LibCallSimplifier::LibCallSimplifier(
+    const DataLayout *DL, const TargetLibraryInfo *TLI,
+    function_ref<void(Instruction *, Value *)> Replacer)
+    : FortifiedSimplifier(DL, TLI), DL(DL), TLI(TLI), UnsafeFPShrink(false),
+      Replacer(Replacer) {}
+
+void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) {
+  // Indirect through the replacer used in this instance.
+  Replacer(I, With);
 }
 
-void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) const {
+/*static*/ void LibCallSimplifier::replaceAllUsesWithDefault(Instruction *I,
+                                                             Value *With) {
   I->replaceAllUsesWith(With);
   I->eraseFromParent();
 }