diff --git a/builtin-fmt-merge-msg.c b/builtin-fmt-merge-msg.c
index 8a3c962f8920bb883287053c850adf78312ff19b..6163bd4975e3e361e36ffc89ea4c91d0edd02949 100644
--- a/builtin-fmt-merge-msg.c
+++ b/builtin-fmt-merge-msg.c
@@ -176,7 +176,7 @@ static void shortlog(const char *name, unsigned char *sha1,
 	struct commit *commit;
 	struct object *branch;
 	struct list subjects = { NULL, NULL, 0, 0 };
-	int flags = UNINTERESTING | TREECHANGE | SEEN | SHOWN | ADDED;
+	int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;
 
 	branch = deref_tag(parse_object(sha1), sha1_to_hex(sha1), 40);
 	if (!branch || branch->type != OBJ_COMMIT)
diff --git a/builtin-log.c b/builtin-log.c
index d6845bc7f8363ccba67aa436e872962195e3e9b5..54ddaad0eccedd74be349d208fecb9a87b143047 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -89,7 +89,7 @@ static int estimate_commit_count(struct rev_info *rev, struct commit_list *list)
 		struct commit *commit = list->item;
 		unsigned int flags = commit->object.flags;
 		list = list->next;
-		if ((flags & TREECHANGE) && !(flags & UNINTERESTING))
+		if (!(flags & (TREESAME | UNINTERESTING)))
 			n++;
 	}
 	return n;
diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index 2dec8873f8a480898c993722ef8d12aec7906d25..0258ec43f96cfd20c06125a905c08227729c7249 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -142,7 +142,7 @@ static int count_distance(struct commit_list *entry)
 
 		if (commit->object.flags & (UNINTERESTING | COUNTED))
 			break;
-		if (commit->object.flags & TREECHANGE)
+		if (!(commit->object.flags & TREESAME))
 			nr++;
 		commit->object.flags |= COUNTED;
 		p = commit->parents;
@@ -198,7 +198,7 @@ static inline int halfway(struct commit_list *p, int nr)
 	/*
 	 * Don't short-cut something we are not going to return!
 	 */
-	if (!(p->item->object.flags & TREECHANGE))
+	if (p->item->object.flags & TREESAME)
 		return 0;
 	if (DEBUG_BISECT)
 		return 0;
@@ -234,7 +234,7 @@ static void show_list(const char *debug, int counted, int nr,
 		char *ep, *sp;
 
 		fprintf(stderr, "%c%c%c ",
-			(flags & TREECHANGE) ? 'T' : ' ',
+			(flags & TREESAME) ? ' ' : 'T',
 			(flags & UNINTERESTING) ? 'U' : ' ',
 			(flags & COUNTED) ? 'C' : ' ');
 		if (commit->util)
@@ -268,7 +268,7 @@ static struct commit_list *best_bisection(struct commit_list *list, int nr)
 		int distance;
 		unsigned flags = p->item->object.flags;
 
-		if (!(flags & TREECHANGE))
+		if (flags & TREESAME)
 			continue;
 		distance = weight(p);
 		if (nr - distance < distance)
@@ -308,7 +308,7 @@ static struct commit_list *best_bisection_sorted(struct commit_list *list, int n
 		int distance;
 		unsigned flags = p->item->object.flags;
 
-		if (!(flags & TREECHANGE))
+		if (flags & TREESAME)
 			continue;
 		distance = weight(p);
 		if (nr - distance < distance)
@@ -362,7 +362,7 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 		p->item->util = &weights[n++];
 		switch (count_interesting_parents(commit)) {
 		case 0:
-			if (flags & TREECHANGE) {
+			if (!(flags & TREESAME)) {
 				weight_set(p, 1);
 				counted++;
 				show_list("bisection 2 count one",
@@ -435,7 +435,7 @@ static struct commit_list *do_find_bisection(struct commit_list *list,
 			 * add one for p itself if p is to be counted,
 			 * otherwise inherit it from q directly.
 			 */
-			if (flags & TREECHANGE) {
+			if (!(flags & TREESAME)) {
 				weight_set(p, weight(q)+1);
 				counted++;
 				show_list("bisection 2 count one",
@@ -482,7 +482,7 @@ static struct commit_list *find_bisection(struct commit_list *list,
 			continue;
 		p->next = last;
 		last = p;
-		if (flags & TREECHANGE)
+		if (!(flags & TREESAME))
 			nr++;
 		on_list++;
 	}
diff --git a/revision.c b/revision.c
index 931f978af91786abcdb0ce6b2ae819c9e4e15902..5796153bbd0b01f94a9c33be16c3bccab86a19a5 100644
--- a/revision.c
+++ b/revision.c
@@ -311,17 +311,15 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 	/*
 	 * If we don't do pruning, everything is interesting
 	 */
-	if (!revs->prune) {
-		commit->object.flags |= TREECHANGE;
+	if (!revs->prune)
 		return;
-	}
 
 	if (!commit->tree)
 		return;
 
 	if (!commit->parents) {
-		if (!rev_same_tree_as_empty(revs, commit->tree))
-			commit->object.flags |= TREECHANGE;
+		if (rev_same_tree_as_empty(revs, commit->tree))
+			commit->object.flags |= TREESAME;
 		return;
 	}
 
@@ -329,10 +327,8 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 	 * Normal non-merge commit? If we don't want to make the
 	 * history dense, we consider it always to be a change..
 	 */
-	if (!revs->dense && !commit->parents->next) {
-		commit->object.flags |= TREECHANGE;
+	if (!revs->dense && !commit->parents->next)
 		return;
-	}
 
 	pp = &commit->parents;
 	while ((parent = *pp) != NULL) {
@@ -357,6 +353,7 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 			}
 			parent->next = NULL;
 			commit->parents = parent;
+			commit->object.flags |= TREESAME;
 			return;
 
 		case REV_TREE_NEW:
@@ -385,7 +382,8 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 		die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 	}
 	if (tree_changed && !tree_same)
-		commit->object.flags |= TREECHANGE;
+		return;
+	commit->object.flags |= TREESAME;
 }
 
 static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
@@ -1354,7 +1352,9 @@ static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp
 				return rewrite_one_error;
 		if (p->parents && p->parents->next)
 			return rewrite_one_ok;
-		if (p->object.flags & (TREECHANGE | UNINTERESTING))
+		if (p->object.flags & UNINTERESTING)
+			return rewrite_one_ok;
+		if (!(p->object.flags & TREESAME))
 			return rewrite_one_ok;
 		if (!p->parents)
 			return rewrite_one_noparents;
@@ -1427,7 +1427,7 @@ enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
 		return commit_ignore;
 	if (revs->prune && revs->dense) {
 		/* Commit without changes? */
-		if (!(commit->object.flags & TREECHANGE)) {
+		if (commit->object.flags & TREESAME) {
 			/* drop merges unless we want parenthood */
 			if (!revs->parents)
 				return commit_ignore;
diff --git a/revision.h b/revision.h
index a79851449c7b71770fc44481e9ba9b562c6a8b5e..992e1e9dd57eac528c3ecaf09987593d525da611 100644
--- a/revision.h
+++ b/revision.h
@@ -3,7 +3,7 @@
 
 #define SEEN		(1u<<0)
 #define UNINTERESTING   (1u<<1)
-#define TREECHANGE	(1u<<2)
+#define TREESAME	(1u<<2)
 #define SHOWN		(1u<<3)
 #define TMP_MARK	(1u<<4) /* for isolated cases; clean after use */
 #define BOUNDARY	(1u<<5)