2 files changed, 76 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 2ca3d12edb7..fd90121bfe3 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -6572,6 +6572,12 @@ CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
   if (!stackE)
     return; // Nothing suspicious was found.
 
+  // Parameters are initalized in the calling scope, so taking the address
+  // of a parameter reference doesn't need a warning.
+  for (auto *DRE : refVars)
+    if (isa<ParmVarDecl>(DRE->getDecl()))
+      return;
+
   SourceLocation diagLoc;
   SourceRange diagRange;
   if (refVars.empty()) {
@@ -6595,6 +6601,13 @@ CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType,
   } else if (isa<AddrLabelExpr>(stackE)) { // address of label.
     S.Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
   } else { // local temporary.
+    // If there is an LValue->RValue conversion, then the value of the
+    // reference type is used, not the reference.
+    if (auto *ICE = dyn_cast<ImplicitCastExpr>(RetValExp)) {
+      if (ICE->getCastKind() == CK_LValueToRValue) {
+        return;
+      }
+    }
     S.Diag(diagLoc, diag::warn_ret_local_temp_addr_ref)
      << lhsType->isReferenceType() << diagRange;
   }
diff --git a/clang/test/SemaCXX/return-stack-addr-2.cpp b/clang/test/SemaCXX/return-stack-addr-2.cpp
index ad27567fcd6..f6ea9b2a738 100644
--- a/clang/test/SemaCXX/return-stack-addr-2.cpp
+++ b/clang/test/SemaCXX/return-stack-addr-2.cpp
@@ -1,5 +1,4 @@
 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -std=c++11 %s
-// expected-no-diagnostics
 
 namespace PR26599 {
 template <typename>
@@ -20,3 +19,66 @@ void *&pointer() {
 }
 }
 
+namespace LocalTemporary {
+
+template <class T>
+class QMap {
+public:
+  T value(const T &t = T()) const {
+    return t;
+  }
+};
+
+struct A {};
+
+void test() {
+  QMap<A *> map;
+  map.value();
+}
+
+typedef int* ptr;
+ptr int1(const ptr &p = ptr()) {
+  return (p);
+}
+
+ptr int2(const ptr &p = nullptr) {
+  return p;
+}
+
+ptr int3() {
+  const ptr &p = ptr();
+  return p;
+}
+
+const int *int4(const int &x = 5) {
+  return &x;
+}
+
+const int *int5(const int &x) {
+  return &x;
+}
+
+const int *int6() {
+  const int &x = 11;  //expected-note{{binding reference variable 'x' here}}
+  return &x;  //expected-warning{{returning address of local temporary object}}
+}
+
+const int *int7(int x) {
+  const int &x2 = x;  // expected-note{{binding reference variable 'x2' here}}
+  const int &x3 = x2;
+  return &x2;  //  expected-warning{{address of stack memory associated with local variable 'x' returned}}
+}
+
+const int *int8(const int &x = 5) {
+  const int &x2 = x;
+  const int &x3 = x2;
+  return &x2;
+}
+
+const int *int9() {
+  const int &x = 5;  // expected-note{{binding reference variable 'x' here}}
+  const int &x2 = x;  // expected-note{{binding reference variable 'x2' here}}
+  const int &x3 = x2;
+  return &x2;  // expected-warning{{returning address of local temporary object}}
+}
+}