diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -25,9 +25,20 @@
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/CommandLine.h"
+
 using namespace clang;
 using namespace CodeGen;
 
+#ifndef NDEBUG
+// TODO: turn on by default when defined(EXPENSIVE_CHECKS) once check-clang is
+// clean
+static llvm::cl::opt<bool> VerifyTypeCache(
+    "verify-type-cache",
+    llvm::cl::desc("Verify that the type cache matches the computed type"),
+    llvm::cl::init(false), llvm::cl::Hidden);
+#endif
+
 CodeGenTypes::CodeGenTypes(CodeGenModule &cgm)
   : CGM(cgm), Context(cgm.getContext()), TheModule(cgm.getModule()),
     Target(cgm.getTarget()), TheCXXABI(cgm.getCXXABI()),
@@ -382,12 +393,10 @@
 
   RecordsBeingLaidOut.erase(Ty);
 
-  if (SkippedLayout)
-    TypeCache.clear();
-
   if (RecordsBeingLaidOut.empty())
     while (!DeferredRecords.empty())
       ConvertRecordDeclType(DeferredRecords.pop_back_val());
+
   return ResultType;
 }
 
@@ -418,8 +427,16 @@
   // See if type is already cached.
   llvm::DenseMap<const Type *, llvm::Type *>::iterator TCI = TypeCache.find(Ty);
   // If type is found in map then use it. Otherwise, convert type T.
-  if (TCI != TypeCache.end())
-    return TCI->second;
+
+  llvm::Type *CachedType = TCI != TypeCache.end() ? TCI->second : nullptr;
+  if (CachedType) {
+#ifndef NDEBUG
+    if (!VerifyTypeCache)
+      return CachedType;
+#else
+    return CachedType;
+#endif
+  }
 
   // If we don't have it in the cache, convert it now.
   llvm::Type *ResultType = nullptr;
@@ -797,7 +814,18 @@
 
   assert(ResultType && "Didn't convert a type?");
 
-  TypeCache[Ty] = ResultType;
+#ifndef NDEBUG
+  if (CachedType) {
+    assert(CachedType == ResultType &&
+           "Cached type doesn't match computed type");
+  }
+#endif
+
+  if (SkippedLayout && (Ty->getTypeClass() == Type::FunctionNoProto ||
+                        Ty->getTypeClass() == Type::FunctionProto))
+    TypeCache.clear();
+  else
+    TypeCache[Ty] = ResultType;
   return ResultType;
 }
 
diff --git a/clang/test/CodeGenCXX/type-cache.cpp b/clang/test/CodeGenCXX/type-cache.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGenCXX/type-cache.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -mllvm -verify-type-cache -emit-llvm %s -o - -triple i386-pc-windows-msvc19.16.0 | FileCheck %s
+// REQUIRES: asserts
+
+// CHECK: call {}* @"?f@@YA?AUz@@XZ"()
+
+struct z {
+  z (*p)();
+};
+
+z f();
+
+void g() {
+  f();
+}