Index: include/llvm/IR/Metadata.h
===================================================================
--- include/llvm/IR/Metadata.h
+++ include/llvm/IR/Metadata.h
@@ -19,18 +19,18 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
-#include "llvm/ADT/ilist_node.h"
-#include "llvm/ADT/iterator_range.h"
 #include "llvm/ADT/None.h"
 #include "llvm/ADT/PointerUnion.h"
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/ilist_node.h"
+#include "llvm/ADT/iterator_range.h"
 #include "llvm/IR/Constant.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Value.h"
-#include "llvm/Support/Casting.h"
 #include "llvm/Support/CBindingWrapping.h"
+#include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <cassert>
 #include <cstddef>
@@ -139,7 +139,7 @@
 
 // Specialized opaque metadata conversions.
 inline Metadata **unwrap(LLVMMetadataRef *MDs) {
-  return reinterpret_cast<Metadata**>(MDs);
+  return reinterpret_cast<Metadata **>(MDs);
 }
 
 #define HANDLE_METADATA(CLASS) class CLASS;
@@ -418,8 +418,7 @@
 class LocalAsMetadata : public ValueAsMetadata {
   friend class ValueAsMetadata;
 
-  LocalAsMetadata(Value *Local)
-      : ValueAsMetadata(LocalAsMetadataKind, Local) {
+  LocalAsMetadata(Value *Local) : ValueAsMetadata(LocalAsMetadataKind, Local) {
     assert(!isa<Constant>(Local) && "Expected local value");
   }
 
@@ -656,16 +655,14 @@
 };
 
 // Specialize DenseMapInfo for AAMDNodes.
-template<>
-struct DenseMapInfo<AAMDNodes> {
+template <> struct DenseMapInfo<AAMDNodes> {
   static inline AAMDNodes getEmptyKey() {
-    return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(),
-                     nullptr, nullptr);
+    return AAMDNodes(DenseMapInfo<MDNode *>::getEmptyKey(), nullptr, nullptr);
   }
 
   static inline AAMDNodes getTombstoneKey() {
-    return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(),
-                     nullptr, nullptr);
+    return AAMDNodes(DenseMapInfo<MDNode *>::getTombstoneKey(), nullptr,
+                     nullptr);
   }
 
   static unsigned getHashValue(const AAMDNodes &Val) {
@@ -1278,6 +1275,11 @@
     if (!Use)
       return;
     *Use = MD;
+
+    if (*Use)
+      MetadataTracking::track(*Use);
+
+    // Equivalent to MetadataTracking::untrack
     Use = nullptr;
   }
 };
@@ -1301,13 +1303,13 @@
 
   explicit NamedMDNode(const Twine &N);
 
-  template<class T1, class T2>
-  class op_iterator_impl :
-      public std::iterator<std::bidirectional_iterator_tag, T2> {
+  template <class T1, class T2>
+  class op_iterator_impl
+      : public std::iterator<std::bidirectional_iterator_tag, T2> {
     const NamedMDNode *Node = nullptr;
     unsigned Idx = 0;
 
-    op_iterator_impl(const NamedMDNode *N, unsigned i) : Node(N), Idx(i) { }
+    op_iterator_impl(const NamedMDNode *N, unsigned i) : Node(N), Idx(i) {}
 
     friend class NamedMDNode;
 
@@ -1373,13 +1375,15 @@
   //
   typedef op_iterator_impl<MDNode *, MDNode> op_iterator;
   op_iterator op_begin() { return op_iterator(this, 0); }
-  op_iterator op_end()   { return op_iterator(this, getNumOperands()); }
+  op_iterator op_end() { return op_iterator(this, getNumOperands()); }
 
   typedef op_iterator_impl<const MDNode *, MDNode> const_op_iterator;
   const_op_iterator op_begin() const { return const_op_iterator(this, 0); }
-  const_op_iterator op_end()   const { return const_op_iterator(this, getNumOperands()); }
+  const_op_iterator op_end() const {
+    return const_op_iterator(this, getNumOperands());
+  }
 
-  inline iterator_range<op_iterator>  operands() {
+  inline iterator_range<op_iterator> operands() {
     return make_range(op_begin(), op_end());
   }
   inline iterator_range<const_op_iterator> operands() const {
Index: test/ThinLTO/X86/Inputs/lazy-load-temporaries-cleanup.b.ll
===================================================================
--- /dev/null
+++ test/ThinLTO/X86/Inputs/lazy-load-temporaries-cleanup.b.ll
@@ -0,0 +1,11 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void  @patatino() {
+  ret void
+}
+
+!named = !{!0}
+
+!0  =  distinct !{!1, i8 0}
+!1  = !{i8 1}
Index: test/ThinLTO/X86/lazy-load-temporaries-cleanup.ll
===================================================================
--- /dev/null
+++ test/ThinLTO/X86/lazy-load-temporaries-cleanup.ll
@@ -0,0 +1,3 @@
+; This test ensures that metadata temporaries are properly tracked, then cleaned up
+
+; RUN: opt -module-summary -bitcode-mdindex-threshold=0 %S/Inputs/lazy-load-temporaries-cleanup.b.ll | llvm-dis -materialize-metadata -set-importing
Index: tools/llvm-dis/llvm-dis.cpp
===================================================================
--- tools/llvm-dis/llvm-dis.cpp
+++ tools/llvm-dis/llvm-dis.cpp
@@ -16,13 +16,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/IR/LLVMContext.h"
 #include "llvm/Bitcode/BitcodeReader.h"
 #include "llvm/IR/AssemblyAnnotationWriter.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/DiagnosticPrinter.h"
 #include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Type.h"
 #include "llvm/Support/CommandLine.h"
@@ -38,21 +38,26 @@
 using namespace llvm;
 
 static cl::opt<std::string>
-InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
+    InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
 
-static cl::opt<std::string>
-OutputFilename("o", cl::desc("Override output filename"),
-               cl::value_desc("filename"));
+static cl::opt<std::string> OutputFilename("o",
+                                           cl::desc("Override output filename"),
+                                           cl::value_desc("filename"));
 
-static cl::opt<bool>
-Force("f", cl::desc("Enable binary output on terminals"));
+static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"));
+
+static cl::opt<bool> DontPrint("disable-output",
+                               cl::desc("Don't output the .ll file"),
+                               cl::Hidden);
 
 static cl::opt<bool>
-DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
+    SetImporting("set-importing",
+                 cl::desc("Set lazy loading to pretend to import a module"),
+                 cl::Hidden);
 
 static cl::opt<bool>
-ShowAnnotations("show-annotations",
-                cl::desc("Add informational comments to the .ll file"));
+    ShowAnnotations("show-annotations",
+                    cl::desc("Add informational comments to the .ll file"));
 
 static cl::opt<bool> PreserveAssemblyUseListOrder(
     "preserve-ll-uselistorder",
@@ -77,7 +82,7 @@
 public:
   void emitFunctionAnnot(const Function *F,
                          formatted_raw_ostream &OS) override {
-    OS << "; [#uses=" << F->getNumUses() << ']';  // Output # uses
+    OS << "; [#uses=" << F->getNumUses() << ']'; // Output # uses
     OS << '\n';
   }
   void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
@@ -96,7 +101,7 @@
           OS << ";";
         }
         OS << " [debug line = ";
-        printDebugLoc(DL,OS);
+        printDebugLoc(DL, OS);
         OS << "]";
       }
       if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
@@ -105,8 +110,7 @@
           OS << ";";
         }
         OS << " [debug variable = " << DDI->getVariable()->getName() << "]";
-      }
-      else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
+      } else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
         if (!Padded) {
           OS.PadToColumn(50);
           OS << ";";
@@ -123,10 +127,18 @@
   raw_ostream &OS = errs();
   OS << (char *)Context << ": ";
   switch (DI.getSeverity()) {
-  case DS_Error: OS << "error: "; break;
-  case DS_Warning: OS << "warning: "; break;
-  case DS_Remark: OS << "remark: "; break;
-  case DS_Note: OS << "note: "; break;
+  case DS_Error:
+    OS << "error: ";
+    break;
+  case DS_Warning:
+    OS << "warning: ";
+    break;
+  case DS_Remark:
+    OS << "remark: ";
+    break;
+  case DS_Note:
+    OS << "note: ";
+    break;
   }
 
   DiagnosticPrinterRawOStream DP(OS);
@@ -142,9 +154,9 @@
 static std::unique_ptr<Module> openInputFile(LLVMContext &Context) {
   std::unique_ptr<MemoryBuffer> MB =
       ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
-  std::unique_ptr<Module> M =
-      ExitOnErr(getOwningLazyBitcodeModule(std::move(MB), Context,
-                                           /*ShouldLazyLoadMetadata=*/true));
+  std::unique_ptr<Module> M = ExitOnErr(getOwningLazyBitcodeModule(
+      std::move(MB), Context,
+      /*ShouldLazyLoadMetadata=*/true, SetImporting));
   if (MaterializeMetadata)
     ExitOnErr(M->materializeMetadata());
   else
@@ -160,7 +172,7 @@
   ExitOnErr.setBanner(std::string(argv[0]) + ": error: ");
 
   LLVMContext Context;
-  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
+  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
 
   Context.setDiagnosticHandler(diagnosticHandler, argv[0]);