Viewing file:  atomic-exchange-1.c (1.31 KB) -rw-r--r--
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/* Test the atomic exchange expansion, shared state space. */
/* { dg-do compile } */
/* { dg-options "-Wno-long-long" } */
enum memmodel
{
MEMMODEL_SEQ_CST = 5
};
unsigned char u8 __attribute__((shared));
unsigned short u16 __attribute__((shared));
unsigned int u32 __attribute__((shared));
unsigned long long int u64 __attribute__((shared));
int
main()
{
__atomic_exchange_n (&u8, 0, MEMMODEL_SEQ_CST);
__atomic_exchange_n (&u16, 0, MEMMODEL_SEQ_CST);
__atomic_exchange_n (&u32, 0, MEMMODEL_SEQ_CST);
__atomic_exchange_n (&u64, 0, MEMMODEL_SEQ_CST);
return 0;
}
/* Not ptx-native, fallback to libatomic.
Libatomic uses generic addressing with a global lock and membar.sys barriers.
We could implement these more efficiently by cloning libatomic for .shared,
using a per-CTA lock and membar.cta barrier. But we'd expect
performance-critical code to use the ptx-native atomic sizes 32 and 64 bit,
so that doesn't seem to be worth the trouble. */
/* { dg-final { scan-assembler-times "(?n)call .* __atomic_exchange_1" 1 } } */
/* { dg-final { scan-assembler-times "(?n)call .* __atomic_exchange_2" 1 } } */
/* { dg-final { scan-assembler-times "atom.shared.exch.b32" 1 } } */
/* { dg-final { scan-assembler-times "atom.shared.exch.b64" 1 } } */
/* { dg-final { scan-assembler-times "membar.cta" 4 } } */
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