Only set share diff if we've confirmed it's a share first.

cgminer.c

@@ -3658,15 +3658,6 @@ static void rebuild_hash(struct work *work)
 		scrypt_regenhash(work);
 	else
 		regen_hash(work);
-
-	work->share_diff = share_diff(work);
-	if (unlikely(work->share_diff >= current_diff)) {
-		work->block = true;
-		work->pool->solved++;
-		found_blocks++;
-		work->mandatory = true;
-		applog(LOG_NOTICE, "Found block for pool %d!", work->pool->pool_no);
-	}
 }
 
 static bool cnx_needed(struct pool *pool);
@@ -6045,6 +6036,7 @@ bool submit_nonce(struct thr_info *thr, struct work *work, uint32_t nonce)
 
 	cgtime(&tv_work_found);
 	*work_nonce = htole32(nonce);
+	work->share_diff = 0;
 
 	/* Do one last check before attempting to submit the work */
 	rebuild_hash(work);
@@ -6060,6 +6052,8 @@ bool submit_nonce(struct thr_info *thr, struct work *work, uint32_t nonce)
 		goto out;
 	}
 
+	work->share_diff = share_diff(work);
+
 	mutex_lock(&stats_lock);
 	total_diff1 += work->device_diff;
 	thr->cgpu->diff1 += work->device_diff;