diff --git a/ruby_atomic.h b/ruby_atomic.h
index 789efdc4ea..e2b1c87a2f 100644
--- a/ruby_atomic.h
+++ b/ruby_atomic.h
@@ -7,7 +7,7 @@ typedef unsigned int rb_atomic_t;
 # define ATOMIC_SET(var, val)  (void)__atomic_exchange_n(&(var), (val), __ATOMIC_SEQ_CST)
 # define ATOMIC_INC(var) __atomic_fetch_add(&(var), 1, __ATOMIC_SEQ_CST)
 # define ATOMIC_DEC(var) __atomic_fetch_sub(&(var), 1, __ATOMIC_SEQ_CST)
-# define ATOMIC_OR(var, val) __atomic_or_fetch(&(var), (val), __ATOMIC_SEQ_CST)
+# define ATOMIC_OR(var, val) __atomic_fetch_or(&(var), (val), __ATOMIC_SEQ_CST)
 # define ATOMIC_EXCHANGE(var, val) __atomic_exchange_n(&(var), (val), __ATOMIC_SEQ_CST)
 # define ATOMIC_CAS(var, oldval, newval) \
 ({ __typeof__(oldval) oldvaldup = (oldval); /* oldval should not be modified */ \
@@ -28,7 +28,7 @@ typedef unsigned int rb_atomic_t; /* Anything OK */
 # define ATOMIC_SET(var, val)  (void)__sync_lock_test_and_set(&(var), (val))
 # define ATOMIC_INC(var) __sync_fetch_and_add(&(var), 1)
 # define ATOMIC_DEC(var) __sync_fetch_and_sub(&(var), 1)
-# define ATOMIC_OR(var, val) __sync_or_and_fetch(&(var), (val))
+# define ATOMIC_OR(var, val) __sync_fetch_and_or(&(var), (val))
 # define ATOMIC_EXCHANGE(var, val) __sync_lock_test_and_set(&(var), (val))
 # define ATOMIC_CAS(var, oldval, newval) __sync_val_compare_and_swap(&(var), (oldval), (newval))