diff --git a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
--- a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
@@ -251,6 +251,7 @@
   struct Signature {
     const ArgTypes ArgTys;
     const QualType RetTy;
+    Signature(){};
     Signature(ArgTypes ArgTys, QualType RetTy) : ArgTys(ArgTys), RetTy(RetTy) {
       assertRetTypeSuitableForSignature(RetTy);
       for (size_t I = 0, E = ArgTys.size(); I != E; ++I) {
@@ -259,6 +260,10 @@
       }
     }
     bool matches(const FunctionDecl *FD) const;
+    bool isIrrelevant() const {
+      return StdLibraryFunctionsChecker::isIrrelevant(RetTy) &&
+             ArgTys.size() == 0;
+    }
 
   private:
     static void assertArgTypeSuitableForSignature(QualType T) {
@@ -316,6 +321,9 @@
     Summary(ArgTypes ArgTys, QualType RetTy, InvalidationKind InvalidationKd)
         : Sign(ArgTys, RetTy), InvalidationKd(InvalidationKd) {}
 
+    // Create with irrelevant signature.
+    Summary(InvalidationKind InvalidationKd) : InvalidationKd(InvalidationKd) {}
+
     Summary &Case(ConstraintSet&& CS) {
       CaseConstraints.push_back(std::move(CS));
       return *this;
@@ -338,6 +346,7 @@
     bool matchesSignature(const FunctionDecl *FD) const {
       return Sign.matches(FD) && validate(FD);
     }
+    bool hasIrrelevantSignature() const { return Sign.isIrrelevant(); }
 
   private:
     // Once we know the exact type of the function then do sanity check on all
@@ -596,19 +605,23 @@
 
 bool StdLibraryFunctionsChecker::Signature::matches(
     const FunctionDecl *FD) const {
+  // Irrelevant signature matches everything.
+  if (isIrrelevant())
+    return true;
+
   // Check number of arguments:
   if (FD->param_size() != ArgTys.size())
     return false;
 
   // Check return type.
-  if (!isIrrelevant(RetTy))
+  if (!StdLibraryFunctionsChecker::isIrrelevant(RetTy))
     if (RetTy != FD->getReturnType().getCanonicalType())
       return false;
 
   // Check argument types.
   for (size_t I = 0, E = ArgTys.size(); I != E; ++I) {
     QualType ArgTy = ArgTys[I];
-    if (isIrrelevant(ArgTy))
+    if (StdLibraryFunctionsChecker::isIrrelevant(ArgTy))
       continue;
     if (ArgTy != FD->getParamDecl(I)->getType().getCanonicalType())
       return false;
@@ -721,15 +734,21 @@
       auto LookupRes = ACtx.getTranslationUnitDecl()->lookup(&II);
       if (LookupRes.size() == 0)
         return;
-      for (Decl *D : LookupRes) {
-        if (auto *FD = dyn_cast<FunctionDecl>(D)) {
-          if (S.matchesSignature(FD)) {
-            S.setFunctionDecl(FD);
-            auto Res = Map.insert({FD->getCanonicalDecl(), S});
-            assert(Res.second && "Function already has a summary set!");
-            (void)Res;
-            return;
-          }
+      // Get all FunctionDecls.
+      SmallVector<FunctionDecl *, 2> FDs;
+      for (Decl *D : LookupRes)
+        if (auto *FD = dyn_cast<FunctionDecl>(D))
+          FDs.push_back(FD);
+      // Irrelevant signatures should be used only without name overloading.
+      if (FDs.size() > 1 && S.hasIrrelevantSignature())
+        return;
+      for (FunctionDecl *FD : FDs) {
+        if (S.matchesSignature(FD)) {
+          S.setFunctionDecl(FD);
+          auto Res = Map.insert({FD->getCanonicalDecl(), S});
+          assert(Res.second && "Function already has a summary set!");
+          (void)Res;
+          return;
         }
       }
     }