Definition of pg_atomic_compare_exchange_u64 requires alignment of
expected pointer on 8-byte boundary.
pg_atomic_compare_exchange_u64(volatile pg_atomic_uint64 *ptr,
uint64 *expected, uint64 newval)
{
#ifndef PG_HAVE_ATOMIC_U64_SIMULATION
AssertPointerAlignment(ptr, 8);
AssertPointerAlignment(expected, 8);
#endif
I wonder if there are platforms where such restriction is actually needed.
And if so, looks like our ./src/test/regress/regress.c is working only
occasionally:
static void
test_atomic_uint64(void)
{
pg_atomic_uint64 var;
uint64 expected;
...
if (!pg_atomic_compare_exchange_u64(&var, &expected, 1))
because there is no warranty that "expected" variable will be aligned on
stack at 8 byte boundary (at least at Win32).
