TLS macOS weirdness

main.c

#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>

static int value = 0xDEADBEEF;
static _Thread_local void *tls = &value;
static pthread_key_t key;

void *worker(void *arg) {
    tls = (void*)0xCAFEBABE;
    pthread_setspecific(key, tls);

    fprintf(
        stderr,
        "[worker]\n"
        "  automatic=%p\n"
        "  &automatic=%p\n"
        "  dynamic=%p\n",
        tls,
        &tls,
        pthread_getspecific(key)
    );

    return NULL;
}

void destructor(void *arg) {
    fprintf(
        stderr,
        "[destructor]\n"
        "  automatic=%p\n"
        "  &automatic=%p\n"
        "  dynamic=%p\n",
        tls,
        &tls,
        arg
    );
}

int main(void) {
    fprintf(stderr, "automatic default = %p\n", tls);
    pthread_key_create(&key, destructor);

    pthread_t thread;
    pthread_create(&thread, NULL, worker, NULL);
    pthread_join(thread, NULL);

    pthread_key_delete(key);
    return EXIT_SUCCESS;
}

output.txt

automatic default = 0x1008b8000
[worker]
  automatic=0xcafebabe
  &automatic=0x600001b18030
  dynamic=0xcafebabe
[destructor]
  automatic=0x1008b8000
  &automatic=0x600001b18030
  dynamic=0xcafebabe