Index: libcxxabi/src/demangle/ItaniumDemangle.h
===================================================================
--- libcxxabi/src/demangle/ItaniumDemangle.h
+++ libcxxabi/src/demangle/ItaniumDemangle.h
@@ -71,7 +71,6 @@
     X(ForwardTemplateReference) \
     X(NameWithTemplateArgs) \
     X(GlobalQualifiedName) \
-    X(StdQualifiedName) \
     X(ExpandedSpecialSubstitution) \
     X(SpecialSubstitution) \
     X(CtorDtorName) \
@@ -1471,21 +1470,6 @@
   }
 };
 
-struct StdQualifiedName : Node {
-  Node *Child;
-
-  StdQualifiedName(Node *Child_) : Node(KStdQualifiedName), Child(Child_) {}
-
-  template<typename Fn> void match(Fn F) const { F(Child); }
-
-  StringView getBaseName() const override { return Child->getBaseName(); }
-
-  void printLeft(OutputBuffer &OB) const override {
-    OB += "std::";
-    Child->print(OB);
-  }
-};
-
 enum class SpecialSubKind {
   allocator,
   basic_string,
@@ -2676,8 +2660,12 @@
   Node *Result = getDerived().parseUnqualifiedName(State);
   if (Result == nullptr)
     return nullptr;
-  if (IsStd)
-    Result = make<StdQualifiedName>(Result);
+  if (IsStd) {
+    if (auto *Std = make<NameType>("std"))
+      Result = make<NestedName>(Std, Result);
+    else
+      return nullptr;
+  }
 
   return Result;
 }
Index: llvm/include/llvm/Demangle/ItaniumDemangle.h
===================================================================
--- llvm/include/llvm/Demangle/ItaniumDemangle.h
+++ llvm/include/llvm/Demangle/ItaniumDemangle.h
@@ -71,7 +71,6 @@
     X(ForwardTemplateReference) \
     X(NameWithTemplateArgs) \
     X(GlobalQualifiedName) \
-    X(StdQualifiedName) \
     X(ExpandedSpecialSubstitution) \
     X(SpecialSubstitution) \
     X(CtorDtorName) \
@@ -1471,21 +1470,6 @@
   }
 };
 
-struct StdQualifiedName : Node {
-  Node *Child;
-
-  StdQualifiedName(Node *Child_) : Node(KStdQualifiedName), Child(Child_) {}
-
-  template<typename Fn> void match(Fn F) const { F(Child); }
-
-  StringView getBaseName() const override { return Child->getBaseName(); }
-
-  void printLeft(OutputBuffer &OB) const override {
-    OB += "std::";
-    Child->print(OB);
-  }
-};
-
 enum class SpecialSubKind {
   allocator,
   basic_string,
@@ -2676,8 +2660,12 @@
   Node *Result = getDerived().parseUnqualifiedName(State);
   if (Result == nullptr)
     return nullptr;
-  if (IsStd)
-    Result = make<StdQualifiedName>(Result);
+  if (IsStd) {
+    if (auto *Std = make<NameType>("std"))
+      Result = make<NestedName>(Std, Result);
+    else
+      return nullptr;
+  }
 
   return Result;
 }
Index: llvm/lib/Demangle/ItaniumDemangle.cpp
===================================================================
--- llvm/lib/Demangle/ItaniumDemangle.cpp
+++ llvm/lib/Demangle/ItaniumDemangle.cpp
@@ -404,9 +404,6 @@
     case Node::KAbiTagAttr:
       Name = static_cast<const AbiTagAttr *>(Name)->Base;
       continue;
-    case Node::KStdQualifiedName:
-      Name = static_cast<const StdQualifiedName *>(Name)->Child;
-      continue;
     case Node::KNestedName:
       Name = static_cast<const NestedName *>(Name)->Name;
       continue;
@@ -446,9 +443,6 @@
   }
 
   switch (Name->getKind()) {
-  case Node::KStdQualifiedName:
-    OB += "std";
-    break;
   case Node::KNestedName:
     static_cast<const NestedName *>(Name)->Qual->print(OB);
     break;
@@ -550,9 +544,6 @@
     case Node::KNestedName:
       N = static_cast<const NestedName *>(N)->Name;
       break;
-    case Node::KStdQualifiedName:
-      N = static_cast<const StdQualifiedName *>(N)->Child;
-      break;
     }
   }
   return false;
Index: llvm/lib/Support/ItaniumManglingCanonicalizer.cpp
===================================================================
--- llvm/lib/Support/ItaniumManglingCanonicalizer.cpp
+++ llvm/lib/Support/ItaniumManglingCanonicalizer.cpp
@@ -189,20 +189,6 @@
   bool trackedNodeIsUsed() const { return TrackedNodeIsUsed; }
 };
 
-/// Convert St3foo to NSt3fooE so that equivalences naming one also affect the
-/// other.
-template<>
-struct CanonicalizerAllocator::MakeNodeImpl<
-           itanium_demangle::StdQualifiedName> {
-  CanonicalizerAllocator &Self;
-  Node *make(Node *Child) {
-    Node *StdNamespace = Self.makeNode<itanium_demangle::NameType>("std");
-    if (!StdNamespace)
-      return nullptr;
-    return Self.makeNode<itanium_demangle::NestedName>(StdNamespace, Child);
-  }
-};
-
 // FIXME: Also expand built-in substitutions?
 
 using CanonicalizingDemangler =