diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.cpp b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
index 2a6216a67e381..f193f959d3a6c 100644
--- a/clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -2189,6 +2189,31 @@ bool ByteCodeExprGen<Emitter>::VisitCXXRewrittenBinaryOperator(
   return this->delegate(E->getSemanticForm());
 }
 
+template <class Emitter>
+bool ByteCodeExprGen<Emitter>::VisitPseudoObjectExpr(
+    const PseudoObjectExpr *E) {
+
+  for (const Expr *SemE : E->semantics()) {
+    if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) {
+      if (SemE == E->getResultExpr())
+        return false;
+
+      if (OVE->isUnique())
+        continue;
+
+      if (!this->discard(OVE))
+        return false;
+    } else if (SemE == E->getResultExpr()) {
+      if (!this->delegate(SemE))
+        return false;
+    } else {
+      if (!this->discard(SemE))
+        return false;
+    }
+  }
+  return true;
+}
+
 template <class Emitter> bool ByteCodeExprGen<Emitter>::discard(const Expr *E) {
   if (E->containsErrors())
     return false;
diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.h b/clang/lib/AST/Interp/ByteCodeExprGen.h
index 8769d1d7b8502..5b3b533dba387 100644
--- a/clang/lib/AST/Interp/ByteCodeExprGen.h
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.h
@@ -117,6 +117,7 @@ class ByteCodeExprGen : public ConstStmtVisitor<ByteCodeExprGen<Emitter>, bool>,
   bool VisitRequiresExpr(const RequiresExpr *E);
   bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E);
   bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E);
+  bool VisitPseudoObjectExpr(const PseudoObjectExpr *E);
 
 protected:
   bool visitExpr(const Expr *E) override;
diff --git a/clang/test/AST/Interp/spaceship.cpp b/clang/test/AST/Interp/spaceship.cpp
new file mode 100644
index 0000000000000..7495b893772e8
--- /dev/null
+++ b/clang/test/AST/Interp/spaceship.cpp
@@ -0,0 +1,232 @@
+// RUN: %clang_cc1 -std=c++2a -verify=both,ref %s -fcxx-exceptions
+// RUN: %clang_cc1 -std=c++2a -verify=both,expected %s -fcxx-exceptions -fexperimental-new-constant-interpreter
+
+namespace std {
+  struct strong_ordering { // both-note 6{{candidate}}
+    int n;
+    constexpr operator int() const { return n; }
+    static const strong_ordering less, equal, greater;
+  };
+  constexpr strong_ordering strong_ordering::less{-1},
+      strong_ordering::equal{0}, strong_ordering::greater{1};
+
+  struct weak_ordering {
+    int n;
+    constexpr weak_ordering(int n) : n(n) {}
+    constexpr weak_ordering(strong_ordering o) : n(o.n) {}
+    constexpr operator int() const { return n; }
+    static const weak_ordering less, equivalent, greater;
+  };
+  constexpr weak_ordering weak_ordering::less{-1},
+      weak_ordering::equivalent{0}, weak_ordering::greater{1};
+
+  struct partial_ordering {
+    double d;
+    constexpr partial_ordering(double d) : d(d) {}
+    constexpr partial_ordering(strong_ordering o) : d(o.n) {}
+    constexpr partial_ordering(weak_ordering o) : d(o.n) {}
+    constexpr operator double() const { return d; }
+    static const partial_ordering less, equivalent, greater, unordered;
+  };
+  constexpr partial_ordering partial_ordering::less{-1},
+      partial_ordering::equivalent{0}, partial_ordering::greater{1},
+      partial_ordering::unordered{__builtin_nan("")};
+
+  static_assert(!(partial_ordering::unordered < 0));
+  static_assert(!(partial_ordering::unordered == 0));
+  static_assert(!(partial_ordering::unordered > 0));
+}
+
+namespace Deletedness {
+  struct A {
+    std::strong_ordering operator<=>(const A&) const;
+  };
+  struct B {
+    bool operator==(const B&) const;
+    bool operator<(const B&) const;
+  };
+  struct C {
+    std::strong_ordering operator<=>(const C&) const = delete; // both-note 2{{deleted}}
+  };
+  struct D1 {
+    bool operator==(const D1&) const;
+    std::strong_ordering operator<=>(int) const; // both-note 2{{function not viable}} both-note 2{{function (with reversed parameter order) not viable}}
+    bool operator<(int) const; // both-note 2{{function not viable}}
+  };
+  struct D2 {
+    bool operator<(const D2&) const;
+    std::strong_ordering operator<=>(int) const; // both-note 2{{function not viable}} both-note 2{{function (with reversed parameter order) not viable}}
+    bool operator==(int) const; // both-note 2{{function not viable}}
+  };
+  struct E {
+    bool operator==(const E&) const;
+    bool operator<(const E&) const = delete; // both-note 2{{deleted}}
+  };
+  struct F {
+    std::strong_ordering operator<=>(const F&) const; // both-note 2{{candidate}}
+    std::strong_ordering operator<=>(F) const; // both-note 2{{candidate}}
+  };
+  struct G1 {
+    bool operator==(const G1&) const;
+    void operator<(const G1&) const;
+  };
+  struct G2 {
+    void operator==(const G2&) const;
+    bool operator<(const G2&) const;
+  };
+  struct H {
+    void operator<=>(const H&) const;
+  };
+
+  // both-note@#base {{deleted comparison function for base class 'C'}}
+  // both-note@#base {{no viable three-way comparison function for base class 'D1'}}
+  // both-note@#base {{three-way comparison cannot be synthesized because there is no viable function for '<' comparison}}
+  // both-note@#base {{no viable 'operator==' for base class 'D2'}}
+  // both-note@#base {{three-way comparison cannot be synthesized because there is no viable function for '==' comparison}}
+  // both-note@#base {{deleted comparison function for base class 'E'}}
+  // both-note@#base {{implied comparison for base class 'F' is ambiguous}}
+  template<typename T> struct Cmp : T { // #base
+    std::strong_ordering operator<=>(const Cmp&) const = default; // #cmp both-note 5{{here}}
+  };
+
+  void use(...);
+  void f() {
+    use(
+      Cmp<A>() <=> Cmp<A>(),
+      Cmp<B>() <=> Cmp<B>(),
+      Cmp<C>() <=> Cmp<C>(), // both-error {{deleted}}
+      Cmp<D1>() <=> Cmp<D1>(), // both-error {{deleted}}
+      Cmp<D2>() <=> Cmp<D2>(), // both-error {{deleted}}
+      Cmp<E>() <=> Cmp<E>(), // both-error {{deleted}}
+      Cmp<F>() <=> Cmp<F>(), // both-error {{deleted}}
+      // FIXME: The following three errors are not very good.
+      // both-error@#cmp {{value of type 'void' is not contextually convertible to 'bool'}}
+      Cmp<G1>() <=> Cmp<G1>(), // both-note-re {{in defaulted three-way comparison operator for '{{.*}}Cmp<{{.*}}G1>' first required here}}j
+      // both-error@#cmp {{value of type 'void' is not contextually convertible to 'bool'}}
+      Cmp<G2>() <=> Cmp<G2>(), // both-note-re {{in defaulted three-way comparison operator for '{{.*}}Cmp<{{.*}}G2>' first required here}}j
+      // both-error@#cmp {{no matching conversion for static_cast from 'void' to 'std::strong_ordering'}}
+      Cmp<H>() <=> Cmp<H>(), // both-note-re {{in defaulted three-way comparison operator for '{{.*}}Cmp<{{.*}}H>' first required here}}j
+      0
+    );
+  }
+
+  // both-note@#arr {{deleted comparison function for member 'arr'}}
+  // both-note@#arr {{no viable three-way comparison function for member 'arr'}}
+  // both-note@#arr {{three-way comparison cannot be synthesized because there is no viable function for '<' comparison}}
+  // both-note@#arr {{no viable 'operator==' for member 'arr'}}
+  // both-note@#arr {{three-way comparison cannot be synthesized because there is no viable function for '==' comparison}}
+  // both-note@#arr {{deleted comparison function for member 'arr'}}
+  // both-note@#arr {{implied comparison for member 'arr' is ambiguous}}
+  template<typename T> struct CmpArray {
+    T arr[3]; // #arr
+    std::strong_ordering operator<=>(const CmpArray&) const = default; // #cmparray both-note 5{{here}}
+  };
+  void g() {
+    use(
+      CmpArray<A>() <=> CmpArray<A>(),
+      CmpArray<B>() <=> CmpArray<B>(),
+      CmpArray<C>() <=> CmpArray<C>(), // both-error {{deleted}}
+      CmpArray<D1>() <=> CmpArray<D1>(), // both-error {{deleted}}
+      CmpArray<D2>() <=> CmpArray<D2>(), // both-error {{deleted}}
+      CmpArray<E>() <=> CmpArray<E>(), // both-error {{deleted}}
+      CmpArray<F>() <=> CmpArray<F>(), // both-error {{deleted}}
+      // FIXME: The following three errors are not very good.
+      // both-error@#cmparray {{value of type 'void' is not contextually convertible to 'bool'}}
+      CmpArray<G1>() <=> CmpArray<G1>(), // both-note-re {{in defaulted three-way comparison operator for '{{.*}}CmpArray<{{.*}}G1>' first required here}}j
+      // both-error@#cmparray {{value of type 'void' is not contextually convertible to 'bool'}}
+      CmpArray<G2>() <=> CmpArray<G2>(), // both-note-re {{in defaulted three-way comparison operator for '{{.*}}CmpArray<{{.*}}G2>' first required here}}j
+      // both-error@#cmparray {{no matching conversion for static_cast from 'void' to 'std::strong_ordering'}}
+      CmpArray<H>() <=> CmpArray<H>(), // both-note-re {{in defaulted three-way comparison operator for '{{.*}}CmpArray<{{.*}}H>' first required here}}j
+      0
+    );
+  }
+}
+
+namespace Access {
+  class A {
+    std::strong_ordering operator<=>(const A &) const; // both-note {{here}}
+  public:
+    bool operator==(const A &) const;
+    bool operator<(const A &) const;
+  };
+  struct B {
+    A a; // both-note {{would invoke a private 'operator<=>'}}
+    friend std::strong_ordering operator<=>(const B &, const B &) = default; // both-warning {{deleted}} both-note{{replace 'default'}}
+  };
+
+  class C {
+    std::strong_ordering operator<=>(const C &); // not viable (not const)
+    bool operator==(const C &) const; // both-note {{here}}
+    bool operator<(const C &) const;
+  };
+  struct D {
+    C c; // both-note {{would invoke a private 'operator=='}}
+    friend std::strong_ordering operator<=>(const D &, const D &) = default; // both-warning {{deleted}} both-note{{replace 'default'}}
+  };
+}
+
+namespace Synthesis {
+  enum Result { False, True, Mu };
+
+  constexpr bool toBool(Result R) {
+    if (R == Mu) throw "should not ask this question";
+    return R == True;
+  }
+
+  struct Val {
+    Result equal, less;
+    constexpr bool operator==(const Val&) const { return toBool(equal); }
+    constexpr bool operator<(const Val&) const { return toBool(less); }
+  };
+
+  template<typename T> struct Cmp {
+    Val val;
+    friend T operator<=>(const Cmp&, const Cmp&) = default; // both-note {{deleted}}
+  };
+
+  template<typename T> constexpr auto cmp(Result equal, Result less = Mu, Result reverse_less = Mu) {
+    return Cmp<T>{equal, less} <=> Cmp<T>{Mu, reverse_less};
+  }
+
+  static_assert(cmp<std::strong_ordering>(True) == 0);
+  static_assert(cmp<std::strong_ordering>(False, True) < 0);
+  static_assert(cmp<std::strong_ordering>(False, False) > 0);
+
+  static_assert(cmp<std::weak_ordering>(True) == 0);
+  static_assert(cmp<std::weak_ordering>(False, True) < 0);
+  static_assert(cmp<std::weak_ordering>(False, False) > 0);
+
+  static_assert(cmp<std::partial_ordering>(True) == 0);
+  static_assert(cmp<std::partial_ordering>(False, True) < 0);
+  static_assert(cmp<std::partial_ordering>(False, False, True) > 0);
+  static_assert(!(cmp<std::partial_ordering>(False, False, False) > 0));
+  static_assert(!(cmp<std::partial_ordering>(False, False, False) == 0));
+  static_assert(!(cmp<std::partial_ordering>(False, False, False) < 0));
+
+  // No synthesis is performed for a custom return type, even if it can be
+  // converted from a standard ordering.
+  struct custom_ordering {
+    custom_ordering(std::strong_ordering o);
+  };
+  void f(Cmp<custom_ordering> c) {
+    c <=> c; // both-error {{deleted}}
+  }
+}
+
+namespace Preference {
+  struct A {
+    A(const A&) = delete; // both-note {{deleted}}
+    // "usable" candidate that can't actually be called
+    friend void operator<=>(A, A); // both-note {{passing}}
+    // Callable candidates for synthesis not considered.
+    friend bool operator==(A, A);
+    friend bool operator<(A, A);
+  };
+
+  struct B {
+    B();
+    A a;
+    std::strong_ordering operator<=>(const B&) const = default; // both-error {{call to deleted constructor of 'A'}}
+  };
+  bool x = B() < B(); // both-note {{in defaulted three-way comparison operator for 'B' first required here}}
+}