diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -640,6 +640,7 @@
     ExpectedStmt VisitBinaryOperator(BinaryOperator *E);
     ExpectedStmt VisitConditionalOperator(ConditionalOperator *E);
     ExpectedStmt VisitBinaryConditionalOperator(BinaryConditionalOperator *E);
+    ExpectedStmt VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E);
     ExpectedStmt VisitOpaqueValueExpr(OpaqueValueExpr *E);
     ExpectedStmt VisitArrayTypeTraitExpr(ArrayTypeTraitExpr *E);
     ExpectedStmt VisitExpressionTraitExpr(ExpressionTraitExpr *E);
@@ -7456,6 +7457,17 @@
       E->getObjectKind());
 }
 
+ExpectedStmt ASTNodeImporter::VisitCXXRewrittenBinaryOperator(
+    CXXRewrittenBinaryOperator *E) {
+  Error Err = Error::success();
+  auto ToSemanticForm = importChecked(Err, E->getSemanticForm());
+  if (Err)
+    return std::move(Err);
+
+  return new (Importer.getToContext())
+      CXXRewrittenBinaryOperator(ToSemanticForm, E->isReversed());
+}
+
 ExpectedStmt ASTNodeImporter::VisitArrayTypeTraitExpr(ArrayTypeTraitExpr *E) {
   Error Err = Error::success();
   auto ToBeginLoc = importChecked(Err, E->getBeginLoc());
diff --git a/clang/test/ASTMerge/cxx-rewritten-binary-operator/Inputs/rbo.cpp b/clang/test/ASTMerge/cxx-rewritten-binary-operator/Inputs/rbo.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/ASTMerge/cxx-rewritten-binary-operator/Inputs/rbo.cpp
@@ -0,0 +1,8 @@
+#include "std-compare.h"
+
+struct A {
+  int a;
+  constexpr auto operator<=>(const A&) const = default;
+};
+
+bool foo(A x, A y) { return x < y; }
diff --git a/clang/test/ASTMerge/cxx-rewritten-binary-operator/Inputs/std-compare.h b/clang/test/ASTMerge/cxx-rewritten-binary-operator/Inputs/std-compare.h
new file mode 100644
--- /dev/null
+++ b/clang/test/ASTMerge/cxx-rewritten-binary-operator/Inputs/std-compare.h
@@ -0,0 +1,307 @@
+#ifndef STD_COMPARE_H
+#define STD_COMPARE_H
+
+namespace std {
+inline namespace __1 {
+
+// exposition only
+enum class _EqResult : unsigned char {
+  __equal = 0,
+  __equiv = __equal,
+};
+
+enum class _OrdResult : signed char {
+  __less = -1,
+  __greater = 1
+};
+
+enum class _NCmpResult : signed char {
+  __unordered = -127
+};
+
+struct _CmpUnspecifiedType;
+using _CmpUnspecifiedParam = void (_CmpUnspecifiedType::*)();
+
+class partial_ordering {
+  using _ValueT = signed char;
+  explicit constexpr partial_ordering(_EqResult __v) noexcept
+      : __value_(_ValueT(__v)) {}
+  explicit constexpr partial_ordering(_OrdResult __v) noexcept
+      : __value_(_ValueT(__v)) {}
+  explicit constexpr partial_ordering(_NCmpResult __v) noexcept
+      : __value_(_ValueT(__v)) {}
+
+  constexpr bool __is_ordered() const noexcept {
+    return __value_ != _ValueT(_NCmpResult::__unordered);
+  }
+
+public:
+  // valid values
+  static const partial_ordering less;
+  static const partial_ordering equivalent;
+  static const partial_ordering greater;
+  static const partial_ordering unordered;
+
+  // comparisons
+  friend constexpr bool operator==(partial_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator!=(partial_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator<(partial_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator<=(partial_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator>(partial_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator>=(partial_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator==(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
+  friend constexpr bool operator!=(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
+  friend constexpr bool operator<(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
+  friend constexpr bool operator<=(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
+  friend constexpr bool operator>(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
+  friend constexpr bool operator>=(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
+
+  friend constexpr partial_ordering operator<=>(partial_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr partial_ordering operator<=>(_CmpUnspecifiedParam, partial_ordering __v) noexcept;
+
+  // test helper
+  constexpr bool test_eq(partial_ordering const &other) const noexcept {
+    return __value_ == other.__value_;
+  }
+
+private:
+  _ValueT __value_;
+};
+
+inline constexpr partial_ordering partial_ordering::less(_OrdResult::__less);
+inline constexpr partial_ordering partial_ordering::equivalent(_EqResult::__equiv);
+inline constexpr partial_ordering partial_ordering::greater(_OrdResult::__greater);
+inline constexpr partial_ordering partial_ordering::unordered(_NCmpResult ::__unordered);
+constexpr bool operator==(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__is_ordered() && __v.__value_ == 0;
+}
+constexpr bool operator<(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__is_ordered() && __v.__value_ < 0;
+}
+constexpr bool operator<=(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__is_ordered() && __v.__value_ <= 0;
+}
+constexpr bool operator>(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__is_ordered() && __v.__value_ > 0;
+}
+constexpr bool operator>=(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__is_ordered() && __v.__value_ >= 0;
+}
+constexpr bool operator==(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
+  return __v.__is_ordered() && 0 == __v.__value_;
+}
+constexpr bool operator<(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
+  return __v.__is_ordered() && 0 < __v.__value_;
+}
+constexpr bool operator<=(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
+  return __v.__is_ordered() && 0 <= __v.__value_;
+}
+constexpr bool operator>(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
+  return __v.__is_ordered() && 0 > __v.__value_;
+}
+constexpr bool operator>=(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
+  return __v.__is_ordered() && 0 >= __v.__value_;
+}
+constexpr bool operator!=(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return !__v.__is_ordered() || __v.__value_ != 0;
+}
+constexpr bool operator!=(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
+  return !__v.__is_ordered() || __v.__value_ != 0;
+}
+
+constexpr partial_ordering operator<=>(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v;
+}
+constexpr partial_ordering operator<=>(_CmpUnspecifiedParam, partial_ordering __v) noexcept {
+  return __v < 0 ? partial_ordering::greater : (__v > 0 ? partial_ordering::less : __v);
+}
+
+class weak_ordering {
+  using _ValueT = signed char;
+  explicit constexpr weak_ordering(_EqResult __v) noexcept : __value_(_ValueT(__v)) {}
+  explicit constexpr weak_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
+
+public:
+  static const weak_ordering less;
+  static const weak_ordering equivalent;
+  static const weak_ordering greater;
+
+  // conversions
+  constexpr operator partial_ordering() const noexcept {
+    return __value_ == 0 ? partial_ordering::equivalent
+                         : (__value_ < 0 ? partial_ordering::less : partial_ordering::greater);
+  }
+
+  // comparisons
+  friend constexpr bool operator==(weak_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator!=(weak_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator<(weak_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator<=(weak_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator>(weak_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator>=(weak_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator==(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
+  friend constexpr bool operator!=(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
+  friend constexpr bool operator<(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
+  friend constexpr bool operator<=(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
+  friend constexpr bool operator>(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
+  friend constexpr bool operator>=(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
+
+  friend constexpr weak_ordering operator<=>(weak_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr weak_ordering operator<=>(_CmpUnspecifiedParam, weak_ordering __v) noexcept;
+
+  // test helper
+  constexpr bool test_eq(weak_ordering const &other) const noexcept {
+    return __value_ == other.__value_;
+  }
+
+private:
+  _ValueT __value_;
+};
+
+inline constexpr weak_ordering weak_ordering::less(_OrdResult::__less);
+inline constexpr weak_ordering weak_ordering::equivalent(_EqResult::__equiv);
+inline constexpr weak_ordering weak_ordering::greater(_OrdResult::__greater);
+constexpr bool operator==(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ == 0;
+}
+constexpr bool operator!=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ != 0;
+}
+constexpr bool operator<(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ < 0;
+}
+constexpr bool operator<=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ <= 0;
+}
+constexpr bool operator>(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ > 0;
+}
+constexpr bool operator>=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ >= 0;
+}
+constexpr bool operator==(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+  return 0 == __v.__value_;
+}
+constexpr bool operator!=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+  return 0 != __v.__value_;
+}
+constexpr bool operator<(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+  return 0 < __v.__value_;
+}
+constexpr bool operator<=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+  return 0 <= __v.__value_;
+}
+constexpr bool operator>(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+  return 0 > __v.__value_;
+}
+constexpr bool operator>=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+  return 0 >= __v.__value_;
+}
+
+constexpr weak_ordering operator<=>(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v;
+}
+constexpr weak_ordering operator<=>(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+  return __v < 0 ? weak_ordering::greater : (__v > 0 ? weak_ordering::less : __v);
+}
+
+class strong_ordering {
+  using _ValueT = signed char;
+  explicit constexpr strong_ordering(_EqResult __v) noexcept : __value_(static_cast<signed char>(__v)) {}
+  explicit constexpr strong_ordering(_OrdResult __v) noexcept : __value_(static_cast<signed char>(__v)) {}
+
+public:
+  static const strong_ordering less;
+  static const strong_ordering equal;
+  static const strong_ordering equivalent;
+  static const strong_ordering greater;
+
+  // conversions
+  constexpr operator partial_ordering() const noexcept {
+    return __value_ == 0 ? partial_ordering::equivalent
+                         : (__value_ < 0 ? partial_ordering::less : partial_ordering::greater);
+  }
+  constexpr operator weak_ordering() const noexcept {
+    return __value_ == 0 ? weak_ordering::equivalent
+                         : (__value_ < 0 ? weak_ordering::less : weak_ordering::greater);
+  }
+
+  // comparisons
+  friend constexpr bool operator==(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator!=(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator<(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator<=(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator>(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator>=(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr bool operator==(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
+  friend constexpr bool operator!=(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
+  friend constexpr bool operator<(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
+  friend constexpr bool operator<=(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
+  friend constexpr bool operator>(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
+  friend constexpr bool operator>=(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
+
+  friend constexpr strong_ordering operator<=>(strong_ordering __v, _CmpUnspecifiedParam) noexcept;
+  friend constexpr strong_ordering operator<=>(_CmpUnspecifiedParam, strong_ordering __v) noexcept;
+
+  // test helper
+  constexpr bool test_eq(strong_ordering const &other) const noexcept {
+    return __value_ == other.__value_;
+  }
+
+private:
+  _ValueT __value_;
+};
+
+inline constexpr strong_ordering strong_ordering::less(_OrdResult::__less);
+inline constexpr strong_ordering strong_ordering::equal(_EqResult::__equal);
+inline constexpr strong_ordering strong_ordering::equivalent(_EqResult::__equiv);
+inline constexpr strong_ordering strong_ordering::greater(_OrdResult::__greater);
+
+constexpr bool operator==(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ == 0;
+}
+constexpr bool operator!=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ != 0;
+}
+constexpr bool operator<(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ < 0;
+}
+constexpr bool operator<=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ <= 0;
+}
+constexpr bool operator>(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ > 0;
+}
+constexpr bool operator>=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v.__value_ >= 0;
+}
+constexpr bool operator==(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+  return 0 == __v.__value_;
+}
+constexpr bool operator!=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+  return 0 != __v.__value_;
+}
+constexpr bool operator<(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+  return 0 < __v.__value_;
+}
+constexpr bool operator<=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+  return 0 <= __v.__value_;
+}
+constexpr bool operator>(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+  return 0 > __v.__value_;
+}
+constexpr bool operator>=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+  return 0 >= __v.__value_;
+}
+
+constexpr strong_ordering operator<=>(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+  return __v;
+}
+constexpr strong_ordering operator<=>(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+  return __v < 0 ? strong_ordering::greater : (__v > 0 ? strong_ordering::less : __v);
+}
+
+} // namespace __1
+} // end namespace std
+
+#endif // STD_COMPARE_H
diff --git a/clang/test/ASTMerge/cxx-rewritten-binary-operator/test.cpp b/clang/test/ASTMerge/cxx-rewritten-binary-operator/test.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/ASTMerge/cxx-rewritten-binary-operator/test.cpp
@@ -0,0 +1,3 @@
+// RUN: %clang_cc1 -std=c++20 -emit-pch -o %t.1.ast %S/Inputs/rbo.cpp
+// RUN: %clang_cc1 -std=c++20 -ast-merge %t.1.ast -fsyntax-only %s 2>&1 | FileCheck --allow-empty %s
+// CHECK-NOT: unsupported AST node