Disable particle cache when vectorisation is enabled.

src/cache.h

@@ -34,6 +34,7 @@
 #define C2_CACHE_SIZE (NUM_VEC_PROC * VEC_SIZE * 6) + (NUM_VEC_PROC * VEC_SIZE)
 #define C2_CACHE_ALIGN sizeof(float) * VEC_SIZE
 
+#ifdef WITH_VECTORIZATION
 /* Cache struct to hold a local copy of a cells' particle
  * properties required for density/force calculations.*/
 struct cache {
@@ -433,4 +434,6 @@ static INLINE void cache_clean(struct cache *c) {
   }
 }
 
+#endif /* WITH_VECTORIZATION */
+
 #endif /* SWIFT_CACHE_H */

src/engine.c

@@ -4264,11 +4264,13 @@ void engine_init(struct engine *e, struct space *s,
       e->runners[k].qid = k * nr_queues / e->nr_threads;
     }
 
+#ifdef WITH_VECTORIZATION
     /* Allocate particle caches. */
     e->runners[k].ci_cache.count = 0;
     e->runners[k].cj_cache.count = 0;
     cache_init(&e->runners[k].ci_cache, CACHE_SIZE);
     cache_init(&e->runners[k].cj_cache, CACHE_SIZE);
+#endif
 
     if (verbose) {
       if (with_aff)
@@ -4355,8 +4357,10 @@ void engine_compute_next_snapshot_time(struct engine *e) {
  */
 void engine_clean(struct engine *e) {
 
+#ifdef WITH_VECTORIZATION
   for (int i = 0; i < e->nr_threads; ++i) cache_clean(&e->runners[i].ci_cache);
   for (int i = 0; i < e->nr_threads; ++i) cache_clean(&e->runners[i].cj_cache);
+#endif
   free(e->runners);
   free(e->snapshotUnits);
   free(e->links);

src/runner.h

@@ -49,11 +49,13 @@ struct runner {
   /*! The engine owing this runner. */
   struct engine *e;
 
+#ifdef WITH_VECTORIZATION
   /*! The particle cache of cell ci. */
   struct cache ci_cache;
 
   /*! The particle cache of cell cj. */
   struct cache cj_cache;
+#endif
 };
 
 /* Function prototypes. */