diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index e9d937fa632c..e3235d34e230 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -256,7 +256,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
 
     // Prepare storage for the result.
     if (!Initializing && !SubExprT) {
-      std::optional<unsigned> LocalIndex = allocateLocal(SubExpr);
+      UnsignedOrNone LocalIndex = allocateLocal(SubExpr);
       if (!LocalIndex)
         return false;
       if (!this->emitGetPtrLocal(*LocalIndex, CE))
@@ -609,7 +609,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
     // We're creating a complex value here, so we need to
     // allocate storage for it.
     if (!Initializing) {
-      std::optional<unsigned> LocalIndex = allocateTemporary(CE);
+      UnsignedOrNone LocalIndex = allocateTemporary(CE);
       if (!LocalIndex)
         return false;
       if (!this->emitGetPtrLocal(*LocalIndex, CE))
@@ -633,7 +633,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
     assert(CE->getType()->isAnyComplexType());
     assert(SubExpr->getType()->isAnyComplexType());
     if (!Initializing) {
-      std::optional<unsigned> LocalIndex = allocateLocal(CE);
+      UnsignedOrNone LocalIndex = allocateLocal(CE);
       if (!LocalIndex)
         return false;
       if (!this->emitGetPtrLocal(*LocalIndex, CE))
@@ -678,7 +678,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
     assert(CE->getType()->isVectorType());
 
     if (!Initializing) {
-      std::optional<unsigned> LocalIndex = allocateLocal(CE);
+      UnsignedOrNone LocalIndex = allocateLocal(CE);
       if (!LocalIndex)
         return false;
       if (!this->emitGetPtrLocal(*LocalIndex, CE))
@@ -722,7 +722,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
     assert(CE->getType()->isVectorType());
 
     if (!Initializing) {
-      std::optional<unsigned> LocalIndex = allocateTemporary(CE);
+      UnsignedOrNone LocalIndex = allocateTemporary(CE);
       if (!LocalIndex)
         return false;
       if (!this->emitGetPtrLocal(*LocalIndex, CE))
@@ -810,7 +810,7 @@ bool Compiler<Emitter>::VisitImaginaryLiteral(const ImaginaryLiteral *E) {
     return true;
 
   if (!Initializing) {
-    std::optional<unsigned> LocalIndex = allocateTemporary(E);
+    UnsignedOrNone LocalIndex = allocateTemporary(E);
     if (!LocalIndex)
       return false;
     if (!this->emitGetPtrLocal(*LocalIndex, E))
@@ -911,7 +911,7 @@ bool Compiler<Emitter>::VisitBinaryOperator(const BinaryOperator *BO) {
 
     // We need a temporary variable holding our return value.
     if (!Initializing) {
-      std::optional<unsigned> ResultIndex = this->allocateLocal(BO);
+      UnsignedOrNone ResultIndex = this->allocateLocal(BO);
       if (!this->emitGetPtrLocal(*ResultIndex, BO))
         return false;
     }
@@ -1151,7 +1151,7 @@ template <class Emitter>
 bool Compiler<Emitter>::VisitComplexBinOp(const BinaryOperator *E) {
   // Prepare storage for result.
   if (!Initializing) {
-    std::optional<unsigned> LocalIndex = allocateTemporary(E);
+    UnsignedOrNone LocalIndex = allocateTemporary(E);
     if (!LocalIndex)
       return false;
     if (!this->emitGetPtrLocal(*LocalIndex, E))
@@ -1210,7 +1210,7 @@ bool Compiler<Emitter>::VisitComplexBinOp(const BinaryOperator *E) {
 
     if (!LHSIsComplex) {
       // This is using the RHS type for the fake-complex LHS.
-      std::optional<unsigned> LocalIndex = allocateTemporary(RHS);
+      UnsignedOrNone LocalIndex = allocateTemporary(RHS);
       if (!LocalIndex)
         return false;
       LHSOffset = *LocalIndex;
@@ -1385,7 +1385,7 @@ bool Compiler<Emitter>::VisitVectorBinOp(const BinaryOperator *E) {
 
   // Prepare storage for result.
   if (!Initializing && !E->isCompoundAssignmentOp()) {
-    std::optional<unsigned> LocalIndex = allocateTemporary(E);
+    UnsignedOrNone LocalIndex = allocateTemporary(E);
     if (!LocalIndex)
       return false;
     if (!this->emitGetPtrLocal(*LocalIndex, E))
@@ -2099,7 +2099,7 @@ bool Compiler<Emitter>::visitCallArgs(ArrayRef<const Expr *> Args,
                                           ExplicitMemberFn);
       }
 
-      std::optional<unsigned> LocalIndex =
+      UnsignedOrNone LocalIndex =
           allocateLocal(std::move(Source), Arg->getType(),
                         /*ExtendingDecl=*/nullptr, ScopeKind::Call);
       if (!LocalIndex)
@@ -2942,7 +2942,7 @@ bool Compiler<Emitter>::VisitMaterializeTemporaryExpr(
       return false;
 
     const Expr *Inner = E->getSubExpr()->skipRValueSubobjectAdjustments();
-    if (std::optional<unsigned> LocalIndex =
+    if (UnsignedOrNone LocalIndex =
             allocateLocal(E, Inner->getType(), E->getExtendingDecl())) {
       InitLinkScope<Emitter> ILS(this, InitLink::Temp(*LocalIndex));
       if (!this->emitGetPtrLocal(*LocalIndex, E))
@@ -3019,7 +3019,7 @@ bool Compiler<Emitter>::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
   unsigned LocalIndex;
   if (T)
     LocalIndex = this->allocateLocalPrimitive(Init, *T, /*IsConst=*/false);
-  else if (std::optional<unsigned> MaybeIndex = this->allocateLocal(Init))
+  else if (UnsignedOrNone MaybeIndex = this->allocateLocal(Init))
     LocalIndex = *MaybeIndex;
   else
     return false;
@@ -3196,7 +3196,7 @@ bool Compiler<Emitter>::VisitCXXConstructExpr(const CXXConstructExpr *E) {
       if (Ctor->isTrivial())
         return true;
       assert(!Initializing);
-      std::optional<unsigned> LocalIndex = allocateLocal(E);
+      UnsignedOrNone LocalIndex = allocateLocal(E);
 
       if (!LocalIndex)
         return false;
@@ -3406,7 +3406,7 @@ bool Compiler<Emitter>::VisitCXXScalarValueInitExpr(
 
   if (const auto *CT = Ty->getAs<ComplexType>()) {
     if (!Initializing) {
-      std::optional<unsigned> LocalIndex = allocateLocal(E);
+      UnsignedOrNone LocalIndex = allocateLocal(E);
       if (!LocalIndex)
         return false;
       if (!this->emitGetPtrLocal(*LocalIndex, E))
@@ -3429,7 +3429,7 @@ bool Compiler<Emitter>::VisitCXXScalarValueInitExpr(
   if (const auto *VT = Ty->getAs<VectorType>()) {
     // FIXME: Code duplication with the _Complex case above.
     if (!Initializing) {
-      std::optional<unsigned> LocalIndex = allocateLocal(E);
+      UnsignedOrNone LocalIndex = allocateLocal(E);
       if (!LocalIndex)
         return false;
       if (!this->emitGetPtrLocal(*LocalIndex, E))
@@ -4055,8 +4055,7 @@ bool Compiler<Emitter>::VisitExtVectorElementExpr(
 
   // Now the vector variable for the return value.
   if (!Initializing) {
-    std::optional<unsigned> ResultIndex;
-    ResultIndex = allocateLocal(E);
+    UnsignedOrNone ResultIndex = allocateLocal(E);
     if (!ResultIndex)
       return false;
     if (!this->emitGetPtrLocal(*ResultIndex, E))
@@ -4180,7 +4179,7 @@ template <class Emitter> bool Compiler<Emitter>::visit(const Expr *E) {
   // Create local variable to hold the return value.
   if (!E->isGLValue() && !E->getType()->isAnyComplexType() &&
       !canClassify(E->getType())) {
-    std::optional<unsigned> LocalIndex = allocateLocal(E);
+    UnsignedOrNone LocalIndex = allocateLocal(E);
     if (!LocalIndex)
       return false;
 
@@ -4547,10 +4546,10 @@ unsigned Compiler<Emitter>::allocateLocalPrimitive(
 }
 
 template <class Emitter>
-std::optional<unsigned>
-Compiler<Emitter>::allocateLocal(DeclTy &&Src, QualType Ty,
-                                 const ValueDecl *ExtendingDecl, ScopeKind SC,
-                                 bool IsConstexprUnknown) {
+UnsignedOrNone Compiler<Emitter>::allocateLocal(DeclTy &&Src, QualType Ty,
+                                                const ValueDecl *ExtendingDecl,
+                                                ScopeKind SC,
+                                                bool IsConstexprUnknown) {
   const ValueDecl *Key = nullptr;
   const Expr *Init = nullptr;
   bool IsTemporary = false;
@@ -4584,7 +4583,7 @@ Compiler<Emitter>::allocateLocal(DeclTy &&Src, QualType Ty,
 }
 
 template <class Emitter>
-std::optional<unsigned> Compiler<Emitter>::allocateTemporary(const Expr *E) {
+UnsignedOrNone Compiler<Emitter>::allocateTemporary(const Expr *E) {
   QualType Ty = E->getType();
   assert(!Ty->isRecordType());
 
@@ -4663,7 +4662,7 @@ bool Compiler<Emitter>::visitExpr(const Expr *E, bool DestroyToplevelScope) {
   // Expressions with a composite return type.
   // For us, that means everything we don't
   // have a PrimType for.
-  if (std::optional<unsigned> LocalOffset = this->allocateLocal(E)) {
+  if (UnsignedOrNone LocalOffset = this->allocateLocal(E)) {
     InitLinkScope<Emitter> ILS(this, InitLink::Temp(*LocalOffset));
     if (!this->emitGetPtrLocal(*LocalOffset, E))
       return false;
@@ -4860,7 +4859,7 @@ VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
         return this->emitSetLocal(*VarT, Offset, VD);
     }
   } else {
-    if (std::optional<unsigned> Offset = this->allocateLocal(
+    if (UnsignedOrNone Offset = this->allocateLocal(
             VD, VD->getType(), nullptr, ScopeKind::Block, IsConstexprUnknown)) {
       if (!Init)
         return true;
@@ -5012,7 +5011,7 @@ bool Compiler<Emitter>::VisitBuiltinCallExpr(const CallExpr *E,
 
   // Non-primitive return type. Prepare storage.
   if (!Initializing && !ReturnT && !ReturnType->isVoidType()) {
-    std::optional<unsigned> LocalIndex = allocateLocal(E);
+    UnsignedOrNone LocalIndex = allocateLocal(E);
     if (!LocalIndex)
       return false;
     if (!this->emitGetPtrLocal(*LocalIndex, E))
@@ -5108,7 +5107,7 @@ bool Compiler<Emitter>::VisitCallExpr(const CallExpr *E) {
       // If we need to discard the return value but the function returns its
       // value via an RVO pointer, we need to create one such pointer just
       // for this call.
-      if (std::optional<unsigned> LocalIndex = allocateLocal(E)) {
+      if (UnsignedOrNone LocalIndex = allocateLocal(E)) {
         if (!this->emitGetPtrLocal(*LocalIndex, E))
           return false;
       }
@@ -5116,7 +5115,7 @@ bool Compiler<Emitter>::VisitCallExpr(const CallExpr *E) {
       // We need the result. Prepare a pointer to return or
       // dup the current one.
       if (!Initializing) {
-        if (std::optional<unsigned> LocalIndex = allocateLocal(E)) {
+        if (UnsignedOrNone LocalIndex = allocateLocal(E)) {
           if (!this->emitGetPtrLocal(*LocalIndex, E))
             return false;
         }
@@ -5152,7 +5151,7 @@ bool Compiler<Emitter>::VisitCallExpr(const CallExpr *E) {
   }
 
   bool Devirtualized = false;
-  std::optional<unsigned> CalleeOffset;
+  UnsignedOrNone CalleeOffset = std::nullopt;
   // Add the (optional, implicit) This pointer.
   if (const auto *MC = dyn_cast<CXXMemberCallExpr>(E)) {
     if (!FuncDecl && classifyPrim(E->getCallee()) == PT_MemberPtr) {
@@ -6560,7 +6559,7 @@ bool Compiler<Emitter>::VisitComplexUnaryOperator(const UnaryOperator *E) {
   OptPrimType ResT = classify(E);
   auto prepareResult = [=]() -> bool {
     if (!ResT && !Initializing) {
-      std::optional<unsigned> LocalIndex = allocateLocal(SubExpr);
+      UnsignedOrNone LocalIndex = allocateLocal(SubExpr);
       if (!LocalIndex)
         return false;
       return this->emitGetPtrLocal(*LocalIndex, E);
@@ -6678,7 +6677,7 @@ bool Compiler<Emitter>::VisitVectorUnaryOperator(const UnaryOperator *E) {
     return this->delegate(SubExpr);
 
   if (!Initializing) {
-    std::optional<unsigned> LocalIndex = allocateLocal(SubExpr);
+    UnsignedOrNone LocalIndex = allocateLocal(SubExpr);
     if (!LocalIndex)
       return false;
     if (!this->emitGetPtrLocal(*LocalIndex, E))
@@ -7282,7 +7281,7 @@ bool Compiler<Emitter>::emitBuiltinBitCast(const CastExpr *E) {
 
   // Prepare storage for the result in case we discard.
   if (DiscardResult && !Initializing && !ToT) {
-    std::optional<unsigned> LocalIndex = allocateLocal(E);
+    UnsignedOrNone LocalIndex = allocateLocal(E);
     if (!LocalIndex)
       return false;
     if (!this->emitGetPtrLocal(*LocalIndex, E))
diff --git a/clang/lib/AST/ByteCode/Compiler.h b/clang/lib/AST/ByteCode/Compiler.h
index cdf587cca663..475faee4d3fd 100644
--- a/clang/lib/AST/ByteCode/Compiler.h
+++ b/clang/lib/AST/ByteCode/Compiler.h
@@ -316,11 +316,11 @@ protected:
                                   bool IsConstexprUnknown = false);
 
   /// Allocates a space storing a local given its type.
-  std::optional<unsigned>
-  allocateLocal(DeclTy &&Decl, QualType Ty = QualType(),
-                const ValueDecl *ExtendingDecl = nullptr,
-                ScopeKind = ScopeKind::Block, bool IsConstexprUnknown = false);
-  std::optional<unsigned> allocateTemporary(const Expr *E);
+  UnsignedOrNone allocateLocal(DeclTy &&Decl, QualType Ty = QualType(),
+                               const ValueDecl *ExtendingDecl = nullptr,
+                               ScopeKind = ScopeKind::Block,
+                               bool IsConstexprUnknown = false);
+  UnsignedOrNone allocateTemporary(const Expr *E);
 
 private:
   friend class VariableScope<Emitter>;
@@ -568,7 +568,7 @@ public:
 
   void addLocal(const Scope::Local &Local) override {
     if (!Idx) {
-      Idx = this->Ctx->Descriptors.size();
+      Idx = static_cast<unsigned>(this->Ctx->Descriptors.size());
       this->Ctx->Descriptors.emplace_back();
       this->Ctx->emitInitScope(*Idx, {});
     }
@@ -616,7 +616,7 @@ public:
   }
 
   /// Index of the scope in the chain.
-  std::optional<unsigned> Idx;
+  UnsignedOrNone Idx = std::nullopt;
 };
 
 /// Scope for storage declared in a compound statement.