diff --git a/src/runner_doiact_vec.c b/src/runner_doiact_vec.c
index b90b8aec75e69f99cf72067acd9473483aeeeb91..652b885673dcdcd50df43da519526812b385a692 100644
--- a/src/runner_doiact_vec.c
+++ b/src/runner_doiact_vec.c
@@ -1718,7 +1718,7 @@ void runner_dopair2_force_vec(struct runner *r, struct cell *ci,
         }
 #endif
 
-        vector v_dx, v_dy, v_dz, v_r2;
+        vector v_dx, v_dy, v_dz;
 
         /* Load 2 sets of vectors from the particle cache. */
         pix.v = vec_load(&ci_cache->x[ci_cache_idx]);