generic/include/clc/cl_khr_int64_base_atomics/atom_cmpxchg.h

_CLC_OVERLOAD _CLC_DECL long atom_cmpxchg(volatile global long *p, long cmp, long val);
_CLC_OVERLOAD _CLC_DECL unsigned long atom_cmpxchg(volatile global unsigned long *p, unsigned long cmp, unsigned long val);
_CLC_OVERLOAD _CLC_DECL long atom_cmpxchg(volatile local long *p, long cmp, long val);
_CLC_OVERLOAD _CLC_DECL unsigned long atom_cmpxchg(volatile local unsigned long *p, unsigned long cmp, unsigned long val);