Viewing file:  bitfields.C (1.51 KB) -rw-r--r--
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/* { dg-do link } */
/* { dg-options "-fno-allow-store-data-races" } */
/* { dg-final { simulate-thread } } */
/* Test that setting <var.a> does not touch either <var.b> or <var.c>.
In the C++ memory model, non contiguous bitfields ("a" and "c"
here) should be considered as distinct memory locations, so we
can't use bit twiddling to set either one. */
#include <stdio.h>
#include "simulate-thread.h"
#define CONSTA 12
static int global;
struct S
{
/* On x86-64, the volatile causes us to access <a> with a 32-bit
access, and thus trigger this test. */
volatile unsigned int a : 4;
unsigned char b;
unsigned int c : 6;
} var;
__attribute__((noinline))
void set_a()
{
var.a = CONSTA;
}
void simulate_thread_other_threads()
{
++global;
var.b = global;
var.c = global;
}
int simulate_thread_step_verify()
{
int ret = 0;
if (var.b != global)
{
printf ("FAIL: Unexpected value: var.b is %d, should be %d\n",
var.b, global);
ret = 1;
}
if (var.c != global)
{
printf ("FAIL: Unexpected value: var.c is %d, should be %d\n",
var.c, global);
ret = 1;
}
return ret;
}
int simulate_thread_final_verify()
{
int ret = simulate_thread_step_verify();
if (var.a != CONSTA)
{
printf ("FAIL: Unexpected value: var.a is %d, should be %d\n",
var.a, CONSTA);
ret = 1;
}
return ret;
}
__attribute__((noinline))
void simulate_thread_main()
{
set_a();
}
int main ()
{
simulate_thread_main();
simulate_thread_done();
return 0;
}
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