diff --git a/llvm/include/llvm/Transforms/Utils/ValueMapper.h b/llvm/include/llvm/Transforms/Utils/ValueMapper.h
--- a/llvm/include/llvm/Transforms/Utils/ValueMapper.h
+++ b/llvm/include/llvm/Transforms/Utils/ValueMapper.h
@@ -158,8 +158,7 @@
   /// Returns a MappingContextID that can be used with the various schedule*()
   /// API to switch in a different value map on-the-fly.
   unsigned
-  registerAlternateMappingContext(ValueToValueMapTy &VM,
-                                  ValueMaterializer *Materializer = nullptr);
+  registerAlternateMappingContext(ValueMaterializer *Materializer = nullptr);
 
   /// Add to the current \a RemapFlags.
   ///
diff --git a/llvm/lib/Linker/IRMover.cpp b/llvm/lib/Linker/IRMover.cpp
--- a/llvm/lib/Linker/IRMover.cpp
+++ b/llvm/lib/Linker/IRMover.cpp
@@ -393,7 +393,6 @@
   /// due to the use of Value handles which the Linker doesn't actually need,
   /// but this allows us to reuse the ValueMapper code.
   ValueToValueMapTy ValueMap;
-  ValueToValueMapTy IndirectSymbolValueMap;
 
   DenseSet<GlobalValue *> ValuesToLink;
   std::vector<GlobalValue *> Worklist;
@@ -529,8 +528,8 @@
         SharedMDs(SharedMDs), IsPerformingImport(IsPerformingImport),
         Mapper(ValueMap, RF_ReuseAndMutateDistinctMDs | RF_IgnoreMissingLocals,
                &TypeMap, &GValMaterializer),
-        IndirectSymbolMCID(Mapper.registerAlternateMappingContext(
-            IndirectSymbolValueMap, &LValMaterializer)) {
+        IndirectSymbolMCID(
+            Mapper.registerAlternateMappingContext(&LValMaterializer)) {
     ValueMap.getMDMap() = std::move(SharedMDs);
     for (GlobalValue *GV : ValuesToLink)
       maybeAdd(GV);
@@ -990,10 +989,6 @@
     auto I = ValueMap.find(SGV);
     if (I != ValueMap.end())
       return cast<Constant>(I->second);
-
-    I = IndirectSymbolValueMap.find(SGV);
-    if (I != IndirectSymbolValueMap.end())
-      return cast<Constant>(I->second);
   }
 
   if (!ShouldLink && ForIndirectSymbol)
@@ -1470,8 +1465,7 @@
     Worklist.pop_back();
 
     // Already mapped.
-    if (ValueMap.find(GV) != ValueMap.end() ||
-        IndirectSymbolValueMap.find(GV) != IndirectSymbolValueMap.end())
+    if (ValueMap.find(GV) != ValueMap.end())
       continue;
 
     assert(!GV->isDeclaration());
diff --git a/llvm/lib/Transforms/Utils/ValueMapper.cpp b/llvm/lib/Transforms/Utils/ValueMapper.cpp
--- a/llvm/lib/Transforms/Utils/ValueMapper.cpp
+++ b/llvm/lib/Transforms/Utils/ValueMapper.cpp
@@ -96,27 +96,14 @@
   } Data;
 };
 
-struct MappingContext {
-  ValueToValueMapTy *VM;
-  ValueMaterializer *Materializer = nullptr;
-
-  /// Construct a MappingContext with a value map and materializer.
-  explicit MappingContext(ValueToValueMapTy &VM,
-                          ValueMaterializer *Materializer = nullptr)
-      : VM(&VM), Materializer(Materializer) {}
-};
-
 class Mapper {
   friend class MDNodeMapper;
 
-#ifndef NDEBUG
-  DenseSet<GlobalValue *> AlreadyScheduled;
-#endif
-
   RemapFlags Flags;
   ValueMapTypeRemapper *TypeMapper;
+  ValueToValueMapTy &VM;
   unsigned CurrentMCID = 0;
-  SmallVector<MappingContext, 2> MCs;
+  SmallVector<ValueMaterializer *, 2> MCs;
   SmallVector<WorklistEntry, 4> Worklist;
   SmallVector<DelayedBasicBlock, 1> DelayedBBs;
   SmallVector<Constant *, 16> AppendingInits;
@@ -124,8 +111,7 @@
 public:
   Mapper(ValueToValueMapTy &VM, RemapFlags Flags,
          ValueMapTypeRemapper *TypeMapper, ValueMaterializer *Materializer)
-      : Flags(Flags), TypeMapper(TypeMapper),
-        MCs(1, MappingContext(VM, Materializer)) {}
+      : Flags(Flags), TypeMapper(TypeMapper), VM(VM), MCs(1, Materializer) {}
 
   /// ValueMapper should explicitly call \a flush() before destruction.
   ~Mapper() { assert(!hasWorkToDo() && "Expected to be flushed"); }
@@ -133,9 +119,8 @@
   bool hasWorkToDo() const { return !Worklist.empty(); }
 
   unsigned
-  registerAlternateMappingContext(ValueToValueMapTy &VM,
-                                  ValueMaterializer *Materializer = nullptr) {
-    MCs.push_back(MappingContext(VM, Materializer));
+  registerAlternateMappingContext(ValueMaterializer *Materializer = nullptr) {
+    MCs.push_back(Materializer);
     return MCs.size() - 1;
   }
 
@@ -174,8 +159,8 @@
                             bool IsOldCtorDtor,
                             ArrayRef<Constant *> NewMembers);
 
-  ValueToValueMapTy &getVM() { return *MCs[CurrentMCID].VM; }
-  ValueMaterializer *getMaterializer() { return MCs[CurrentMCID].Materializer; }
+  ValueToValueMapTy &getVM() { return VM; }
+  ValueMaterializer *getMaterializer() { return MCs[CurrentMCID]; }
 
   Value *mapBlockAddress(const BlockAddress &BA);
 
@@ -1038,7 +1023,6 @@
 
 void Mapper::scheduleMapGlobalInitializer(GlobalVariable &GV, Constant &Init,
                                           unsigned MCID) {
-  assert(AlreadyScheduled.insert(&GV).second && "Should not reschedule");
   assert(MCID < MCs.size() && "Invalid mapping context");
 
   WorklistEntry WE;
@@ -1054,7 +1038,6 @@
                                           bool IsOldCtorDtor,
                                           ArrayRef<Constant *> NewMembers,
                                           unsigned MCID) {
-  assert(AlreadyScheduled.insert(&GV).second && "Should not reschedule");
   assert(MCID < MCs.size() && "Invalid mapping context");
 
   WorklistEntry WE;
@@ -1070,7 +1053,6 @@
 
 void Mapper::scheduleMapGlobalIndirectSymbol(GlobalIndirectSymbol &GIS,
                                              Constant &Target, unsigned MCID) {
-  assert(AlreadyScheduled.insert(&GIS).second && "Should not reschedule");
   assert(MCID < MCs.size() && "Invalid mapping context");
 
   WorklistEntry WE;
@@ -1082,7 +1064,6 @@
 }
 
 void Mapper::scheduleRemapFunction(Function &F, unsigned MCID) {
-  assert(AlreadyScheduled.insert(&F).second && "Should not reschedule");
   assert(MCID < MCs.size() && "Invalid mapping context");
 
   WorklistEntry WE;
@@ -1126,9 +1107,8 @@
 ValueMapper::~ValueMapper() { delete getAsMapper(pImpl); }
 
 unsigned
-ValueMapper::registerAlternateMappingContext(ValueToValueMapTy &VM,
-                                             ValueMaterializer *Materializer) {
-  return getAsMapper(pImpl)->registerAlternateMappingContext(VM, Materializer);
+ValueMapper::registerAlternateMappingContext(ValueMaterializer *Materializer) {
+  return getAsMapper(pImpl)->registerAlternateMappingContext(Materializer);
 }
 
 void ValueMapper::addFlags(RemapFlags Flags) {
diff --git a/llvm/test/Linker/global-alias-value-map.ll b/llvm/test/Linker/global-alias-value-map.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Linker/global-alias-value-map.ll
@@ -0,0 +1,19 @@
+; RUN: llvm-link %s -o /dev/null
+
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-apple-macosx10.15.0"
+
+@"$ss8SIMDMaskVyxGs11SIMDStoragessADPy6ScalarQzSicigTW.ptrauth" = dso_local local_unnamed_addr constant i8* bitcast (void (i1*, i64, i64*, i64*, i8**)* @"$ss8SIMDMaskVyxGs11SIMDStoragessADPy6ScalarQzSicigTW" to i8*)
+
+@"$ss27ExpressibleByIntegerLiteralTL" = alias i32, getelementptr (i32, i32* getelementptr inbounds (<{ i32, i32 }>, <{ i32, i32 }>* @"$ss27ExpressibleByIntegerLiteralMp", i32 0, i32 0), i32 0)
+
+@"$ss27ExpressibleByIntegerLiteralMp" = constant <{ i32, i32 }> <{ i32 0, i32 trunc (i64 sub (i64 ptrtoint (<{ i32, i32 }>* @"$ss35_ExpressibleByBuiltinIntegerLiteralMp" to i64), i64 ptrtoint (i32* getelementptr inbounds (<{ i32, i32 }>, <{ i32, i32 }>* @"$ss27ExpressibleByIntegerLiteralMp", i32 0, i32 0) to i64)) to i32)}>
+
+@"$ss35_ExpressibleByBuiltinIntegerLiteralMp" = constant <{ i32, i32 }> <{ i32 0, i32 0 }>
+
+define linkonce_odr hidden void @"$ss8SIMDMaskVyxGs11SIMDStoragessADPy6ScalarQzSicigTW"(i1* noalias nocapture sret(i1) %0, i64 %1, i64* noalias nocapture swiftself %2, i64* %3, i8** %4) {
+  %6 = call i8** @swift_getAssociatedConformanceWitness(i32* nonnull @"$ss27ExpressibleByIntegerLiteralTL")
+  ret void
+}
+
+declare i8** @swift_getAssociatedConformanceWitness(i32*) local_unnamed_addr