avoid atomic operations on statistics if zero
@@ -70,6 +70,7 @@ void _mi_stat_decrease(mi_stat_count_t* stat, size_t amount) {
// must be thread safe as it is called from stats_merge
static void mi_stat_add(mi_stat_count_t* stat, const mi_stat_count_t* src, int64_t unit) {
if (stat==src) return;
+ if (src->allocated==0 && src->freed==0) return;
mi_atomic_addi64( &stat->allocated, src->allocated * unit);
mi_atomic_addi64( &stat->current, src->current * unit);
mi_atomic_addi64( &stat->freed, src->freed * unit);
