LLVM ERROR: Associative COMDAT symbol 'std.time.Duration.to_nano' is not a key for its COMDAT.

[LukyGuyLucky]

Below execise is modified from https://github.com/c3lang/c3c/blob/master/test/unit/stdlib/threads/mutex.c3,it compiles and runs fine when using below commandline:
c3c compile-run mutex01.c3

but when I tried it with
c3c compile -Oz mutex01.c3
the compiler says:

LLVM ERROR: Associative COMDAT symbol 'std.time.Duration.to_nano' is not a key for its COMDAT.

So was I missing something?

module mutex01;

import std::thread;
import std::os;
import std::io;
const TEST_MAGNITUDE = 10;

int counter;
fn void! own_mutex(Mutex* m)
{
    m.lock()!!;
    for(int i=0;i<5;i++)
    {
        counter++;
        io::print(counter);
        thread::sleep_ms(100);
        counter++;
        io::print(counter);
        thread::sleep_ms(50);
    }
    m.unlock()!!;
}

fn void! ensure_owner_checks() 
{
    Mutex m;
    m.init()!;
	
    Thread[3 * TEST_MAGNITUDE] threads;
    
    foreach(&t : threads)
    {
        t.create((ThreadFn)&own_mutex, &m)!;
    }

    foreach(&t : threads)
    {
        t.join()!;
    }

    own_mutex(&m)!;
    
}
fn void main()
{
   
    ensure_owner_checks()!!;
    io::printn("Done.");
}