diff --git a/mercurial/cext/revlog.c b/mercurial/cext/revlog.c
--- a/mercurial/cext/revlog.c
+++ b/mercurial/cext/revlog.c
@@ -1062,7 +1062,7 @@
 		v = n->children[k];
 
 		if (v == 0) {
-			n->children[k] = -rev - 1;
+			n->children[k] = -(rev + 1);
 			return 0;
 		}
 		if (v < 0) {
@@ -1072,7 +1072,7 @@
 			if (oldnode == NULL)
 				return -1;
 			if (!memcmp(oldnode, node, 20)) {
-				n->children[k] = -rev - 1;
+				n->children[k] = -(rev + 1);
 				return 0;
 			}
 			noff = nt_new(self);