llvm/libclc/generic/lib/atomic/atomic_xchg.cl

#include <clc/clc.h>

_CLC_OVERLOAD _CLC_DEF float atomic_xchg(volatile global float *p, float val) {
  return as_float(atomic_xchg((volatile global uint *)p, as_uint(val)));
}

_CLC_OVERLOAD _CLC_DEF float atomic_xchg(volatile local float *p, float val) {
  return as_float(atomic_xchg((volatile local uint *)p, as_uint(val)));
}

#define IMPL(TYPE, AS) \
_CLC_OVERLOAD _CLC_DEF TYPE atomic_xchg(volatile AS TYPE *p, TYPE val) { \
  return __sync_swap_4(p, val); \
}

IMPL(int, global)
IMPL(unsigned int, global)
IMPL(int, local)
IMPL(unsigned int, local)
#undef IMPL