--- a/js/src/jit/MIR.cpp
+++ b/js/src/jit/MIR.cpp
@@ -5426,16 +5426,18 @@ MWasmCall::NewBuiltinInstanceMethodCall(
                                         const Args& args,
                                         MIRType resultType,
                                         uint32_t spIncrement)
 {
     auto callee = wasm::CalleeDesc::builtinInstanceMethod(builtin);
     MWasmCall* call = MWasmCall::New(alloc, desc, callee, args, resultType, spIncrement,
                                      MWasmCall::DontSaveTls, nullptr);
 
+    if (!call)
+        return nullptr;
     MOZ_ASSERT(instanceArg != ABIArg()); // instanceArg must be initialized.
     call->instanceArg_ = instanceArg;
     return call;
 }
 
 void
 MSqrt::trySpecializeFloat32(TempAllocator& alloc) {
     if (!input()->canProduceFloat32() || !CheckUsesAreFloat32Consumers(this)) {