gcc/testsuite/gcc.dg/simulate-thread/speculative-store.c

/* { dg-do link } */
/* { dg-options "-fno-allow-store-data-races" } */
/* { dg-final { simulate-thread } } */

#include <stdio.h>
#include "simulate-thread.h"

/* This file tests that speculative store movement out of a loop doesn't 
   happen.  This is disallowed when -fno-allow-store-data-races.  */

int global = 100;

/* Other thread makes sure global is 100 before the next instruction is
 * exceuted.  */
void simulate_thread_other_threads() 
{
  global = 100;
}

int simulate_thread_step_verify()
{
  if (global != 100)
    {
      printf("FAIL: global variable was assigned to.  \n");
      return 1;
    }
  return 0;
}

int simulate_thread_final_verify()
{
  return 0;
}

/* The variable global should never be assigned if func(0) is called.
   This tests store movement out of loop thats never executed. */
void test (int y)
{
  int x;
  for (x=0; x< y; x++)
    {
       global = y;   /* This should never speculatively execute.  */
    }
}

__attribute__((noinline))
void simulate_thread_main()
{
  test(0);
  simulate_thread_done();
}

__attribute__((noinline))
int main()
{
  simulate_thread_main();
  return 0;
}