diff --git a/llvm/include/llvm/Analysis/IRSimilarityIdentifier.h b/llvm/include/llvm/Analysis/IRSimilarityIdentifier.h
--- a/llvm/include/llvm/Analysis/IRSimilarityIdentifier.h
+++ b/llvm/include/llvm/Analysis/IRSimilarityIdentifier.h
@@ -654,12 +654,6 @@
   IRSimilarityIdentifier()
       : Mapper(&InstDataAllocator, &InstDataListAllocator) {}
 
-  /// \param M the module to find similarity in.
-  explicit IRSimilarityIdentifier(Module &M)
-      : Mapper(&InstDataAllocator, &InstDataListAllocator) {
-    findSimilarity(M);
-  }
-
 private:
   /// Map the instructions in the module to unsigned integers, using mapping
   /// already present in the Mapper if possible.
diff --git a/llvm/lib/Analysis/IRSimilarityIdentifier.cpp b/llvm/lib/Analysis/IRSimilarityIdentifier.cpp
--- a/llvm/lib/Analysis/IRSimilarityIdentifier.cpp
+++ b/llvm/lib/Analysis/IRSimilarityIdentifier.cpp
@@ -891,7 +891,7 @@
 }
 
 bool IRSimilarityIdentifierWrapperPass::doInitialization(Module &M) {
-  IRSI.reset(new IRSimilarityIdentifier(M));
+  IRSI.reset(new IRSimilarityIdentifier());
   return false;
 }
 
@@ -901,8 +901,7 @@
 }
 
 bool IRSimilarityIdentifierWrapperPass::runOnModule(Module &M) {
-  // All the real work is done in the constructor for the pass.
-  IRSI.reset(new IRSimilarityIdentifier(M));
+  IRSI->findSimilarity(M);
   return false;
 }
 
@@ -910,7 +909,9 @@
 IRSimilarityIdentifier IRSimilarityAnalysis::run(Module &M,
                                                ModuleAnalysisManager &) {
 
-  return IRSimilarityIdentifier(M);
+  auto IRSI = IRSimilarityIdentifier();
+  IRSI.findSimilarity(M);
+  return IRSI;
 }
 
 PreservedAnalyses