diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 8b896f5..4af0b58 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -414,19 +414,30 @@
 
 static void hists__compute_resort(struct hists *hists)
 {
-	struct rb_root tmp = RB_ROOT;
-	struct rb_node *next = rb_first(&hists->entries);
+	struct rb_root *root;
+	struct rb_node *next;
+
+	if (sort__need_collapse)
+		root = &hists->entries_collapsed;
+	else
+		root = hists->entries_in;
+
+	hists->entries = RB_ROOT;
+	next = rb_first(root);
+
+	hists->nr_entries = 0;
+	hists->stats.total_period = 0;
+	hists__reset_col_len(hists);
 
 	while (next != NULL) {
-		struct hist_entry *he = rb_entry(next, struct hist_entry, rb_node);
+		struct hist_entry *he;
 
-		next = rb_next(&he->rb_node);
+		he = rb_entry(next, struct hist_entry, rb_node_in);
+		next = rb_next(&he->rb_node_in);
 
-		rb_erase(&he->rb_node, &hists->entries);
-		insert_hist_entry_by_compute(&tmp, he, compute);
+		insert_hist_entry_by_compute(&hists->entries, he, compute);
+		hists__inc_nr_entries(hists, he);
 	}
-
-	hists->entries = tmp;
 }
 
 static void hists__process(struct hists *old, struct hists *new)
@@ -438,11 +449,11 @@
 	else
 		hists__link(new, old);
 
-	hists__output_resort(new);
-
 	if (sort_compute) {
 		hists__precompute(new);
 		hists__compute_resort(new);
+	} else {
+		hists__output_resort(new);
 	}
 
 	hists__fprintf(new, true, 0, 0, stdout);