diff --git a/src/vector.c b/src/vector.c
index a5b2aac..0ced82b 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -916,15 +916,19 @@ vector_concat(PG_FUNCTION_ARGS)
 	Vector	   *b = PG_GETARG_VECTOR_P(1);
 	Vector	   *result;
 	int			dim = a->dim + b->dim;
+	int     dim_a = a->dim;
+	int     dim_b = b->dim;
 
 	CheckDim(dim);
 	result = InitVector(dim);
 
-	for (int i = 0; i < a->dim; i++)
+	/* Auto-vectorized */
+	for (int i = 0; i < dim_a; i++)
 		result->x[i] = a->x[i];
 
-	for (int i = 0; i < b->dim; i++)
-		result->x[i + a->dim] = b->x[i];
+	/* Auto-vectorized */
+	for (int i = 0; i < dim_b; i++)
+		result->x[i + dim_a] = b->x[i];
 
 	PG_RETURN_POINTER(result);
 }