diff --git a/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp b/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
--- a/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
@@ -423,6 +423,14 @@
     return UnknownVal();
   }
 
+  if (op == BinaryOperatorKind::BO_Cmp) {
+    // We can't reason about C++20 spaceship operator yet.
+    //
+    // FIXME: Support C++20 spaceship operator.
+    //        The main problem here is that the result is not integer.
+    return UnknownVal();
+  }
+
   if (Optional<Loc> LV = lhs.getAs<Loc>()) {
     if (Optional<Loc> RV = rhs.getAs<Loc>())
       return evalBinOpLL(state, op, *LV, *RV, type);
diff --git a/clang/test/Analysis/PR47511.cpp b/clang/test/Analysis/PR47511.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/Analysis/PR47511.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_analyze_cc1 -std=c++20 -w -analyzer-checker=core -verify %s
+
+// expected-no-diagnostics
+
+namespace std {
+struct strong_ordering {
+  int n;
+  constexpr operator int() const { return n; }
+  static const strong_ordering equal, greater, less;
+};
+constexpr strong_ordering strong_ordering::equal = {0};
+constexpr strong_ordering strong_ordering::greater = {1};
+constexpr strong_ordering strong_ordering::less = {-1};
+} // namespace std
+
+void test() {
+  // no crash
+  (void)(0 <=> 0);
+}