message: Fix singlepass compilation error.
diff: @@ -2417,7 +2417,14 @@ impl FunctionCodeGenerator<CodegenError> for X64FunctionCode {
  loc_b,
  );
  a.emit_jmp(Condition::NotEqual, normal_path);
  - a.emit_mov(Size::S64, Location::Imm64(0), ret);
  + Self::emit_relaxed_binop(
  + a,
  + &mut self.machine,
  + Assembler::emit_mov,
  + Size::S64,
  + Location::Imm64(0),
  + ret,
  + );
  a.emit_jmp(Condition::None, end);
  a.emit_label(normal_path);
  @@ -4531,9 +4538,14 @@ impl FunctionCodeGenerator<CodegenError> for X64FunctionCode {
  |a, m, addr| {
  match ret {
  Location::GPR(_) => {}
  - _ => {
  - a.emit_mov(Size::S64, Location::Imm64(0), ret);
  + Location::Memory(base, offset) => {
  + a.emit_mov(
  + Size::S32,
  + Location::Imm32(0),
  + Location::Memory(base, offset + 4),
  + ); // clear upper bits
  }
  + _ => unreachable!(),
  }
  Self::emit_relaxed_binop(
  a,
  