diff --git a/libgcc/sync.c b/libgcc/sync.c
index 1cb81661319..18b91164a80 100644
--- a/libgcc/sync.c
+++ b/libgcc/sync.c
@@ -124,10 +124,9 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 
 /* Find an appropriate type TYPE for SIZE and invoke DEFINE (FN, SIZE, TYPE).
 
-   The types chosen here may be incorrect for some targets.
-   For example, targets with 16-byte atomicity support might not
-   support OImode.  We would need some kind of target-specific
-   override if that becomes a problem.  */
+   The types chosen here are based on standard GCC modes.
+   If a target supports atomic operations for a given SIZE but lacks
+   the corresponding mode, a target-specific override will be needed.  */
 
 #if SIZE == 1 && __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1
 
@@ -151,8 +150,8 @@ DEFINE (FN, 8, UDItype)
 
 #elif SIZE == 16 && __GCC_HAVE_SYNC_COMPARE_AND_SWAP_16
 
-typedef unsigned int UOItype __attribute__((mode (OI)));
-DEFINE (FN, 8, UOItype)
+typedef unsigned int UTItype __attribute__((mode (TI)));
+DEFINE (FN, 16, UTItype)
 
 #endif