Index: include/clang/Basic/BuiltinsWebAssembly.def
===================================================================
--- include/clang/Basic/BuiltinsWebAssembly.def
+++ include/clang/Basic/BuiltinsWebAssembly.def
@@ -23,5 +23,6 @@
 
 // Exception handling builtins.
 BUILTIN(__builtin_wasm_throw, "vUiv*", "r")
+BUILTIN(__builtin_wasm_rethrow, "v", "r")
 
 #undef BUILTIN
Index: lib/CodeGen/CGBuiltin.cpp
===================================================================
--- lib/CodeGen/CGBuiltin.cpp
+++ lib/CodeGen/CGBuiltin.cpp
@@ -9574,6 +9574,10 @@
     Value *Callee = CGM.getIntrinsic(Intrinsic::wasm_throw);
     return Builder.CreateCall(Callee, {Tag, Obj});
   }
+  case WebAssembly::BI__builtin_wasm_rethrow: {
+    Value *Callee = CGM.getIntrinsic(Intrinsic::wasm_rethrow);
+    return Builder.CreateCall(Callee);
+  }
 
   default:
     return nullptr;
Index: test/CodeGen/builtins-wasm.c
===================================================================
--- test/CodeGen/builtins-wasm.c
+++ test/CodeGen/builtins-wasm.c
@@ -20,3 +20,9 @@
 // WEBASSEMBLY32: call void @llvm.wasm.throw(i32 %{{.*}}, i8* %{{.*}})
 // WEBASSEMBLY64: call void @llvm.wasm.throw(i32 %{{.*}}, i8* %{{.*}})
 }
+
+void f4() {
+  return __builtin_wasm_rethrow();
+// WEBASSEMBLY32: call void @llvm.wasm.rethrow()
+// WEBASSEMBLY64: call void @llvm.wasm.rethrow()
+}