@@ -338,6 +338,14 @@ build_one (function_builder &b, const char *signature,
unsigned int ti, unsigned int gi, unsigned int pi,
bool force_direct_overloads)
{
+ /* For simplicity, function definitions are allowed to use the group
+ suffix lists vg2 and vg4 for shapes that have _single forms,
+ even though the _single form applies only to vgNx2 and vgNx4,
+ not to vgNx1. */
+ if (mode_suffix_id == MODE_single
+ && group_suffixes[group.groups[gi]].vectors_per_tuple == 1)
+ return;
+
/* Byte forms of svdupq take 16 arguments. */
auto_vec<tree, 16> argument_types;
function_instance instance (group.base_name, *group.base, *group.shape,