Index: clang/lib/AST/Interp/Interp.h
===================================================================
--- clang/lib/AST/Interp/Interp.h
+++ clang/lib/AST/Interp/Interp.h
@@ -1499,10 +1499,11 @@
 }
 
 inline bool Call(InterpState &S, CodePtr &PC, const Function *Func) {
-  auto NewFrame = std::make_unique<InterpFrame>(S, Func, PC);
-  Pointer ThisPtr;
   if (Func->hasThisPointer()) {
-    ThisPtr = NewFrame->getThis();
+    size_t ThisOffset =
+        Func->getArgSize() + (Func->hasRVO() ? primSize(PT_Ptr) : 0);
+    const Pointer &ThisPtr = S.Stk.peek<Pointer>(ThisOffset);
+
     if (!CheckInvoke(S, PC, ThisPtr))
       return false;
 
@@ -1513,6 +1514,7 @@
   if (!CheckCallable(S, PC, Func))
     return false;
 
+  auto NewFrame = std::make_unique<InterpFrame>(S, Func, PC);
   InterpFrame *FrameBefore = S.Current;
   S.Current = NewFrame.get();
 
Index: clang/lib/AST/Interp/InterpStack.h
===================================================================
--- clang/lib/AST/Interp/InterpStack.h
+++ clang/lib/AST/Interp/InterpStack.h
@@ -64,11 +64,16 @@
 
   /// Returns a reference to the value on the top of the stack.
   template <typename T> T &peek() const {
-    return *reinterpret_cast<T *>(peek(aligned_size<T>()));
+    return *reinterpret_cast<T *>(peekData(aligned_size<T>()));
+  }
+
+  template <typename T> T &peek(size_t Offset) const {
+    assert(aligned(Offset));
+    return *reinterpret_cast<T *>(peekData(Offset));
   }
 
   /// Returns a pointer to the top object.
-  void *top() const { return Chunk ? peek(0) : nullptr; }
+  void *top() const { return Chunk ? peekData(0) : nullptr; }
 
   /// Returns the size of the stack in bytes.
   size_t size() const { return StackSize; }
@@ -90,7 +95,7 @@
   /// Grows the stack to accommodate a value and returns a pointer to it.
   void *grow(size_t Size);
   /// Returns a pointer from the top of the stack.
-  void *peek(size_t Size) const;
+  void *peekData(size_t Size) const;
   /// Shrinks the stack.
   void shrink(size_t Size);
 
Index: clang/lib/AST/Interp/InterpStack.cpp
===================================================================
--- clang/lib/AST/Interp/InterpStack.cpp
+++ clang/lib/AST/Interp/InterpStack.cpp
@@ -46,7 +46,7 @@
   return Object;
 }
 
-void *InterpStack::peek(size_t Size) const {
+void *InterpStack::peekData(size_t Size) const {
   assert(Chunk && "Stack is empty!");
 
   StackChunk *Ptr = Chunk;