From 40792a3aa1a7dde0d3a2e8de0e89cc7b94d9d3be Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Fri, 20 Aug 2021 00:44:24 +0200
Subject: [PATCH] faster get_side hard case

---
 rulegen.cpp | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/rulegen.cpp b/rulegen.cpp
index edffc8a8..3f03ce3f 100644
--- a/rulegen.cpp
+++ b/rulegen.cpp
@@ -852,10 +852,16 @@ int get_side(twalker what) {
       debuglist = {what, to_what, wl, wr};
       throw rulegen_failure("xsidefreeze");
       }
-    treewalk(wl, -1);
-    treewalk(wr, +1);
-    if(wl == to_what) return sidecache[what] = +1;
-    if(wr == to_what) return sidecache[what] = -1;
+    bool gl = wl.at->dist <= wr.at->dist;
+    bool gr = wl.at->dist >= wr.at->dist;
+    if(gl) {
+      treewalk(wl, -1);
+      if(wl == to_what) return sidecache[what] = +1;
+      }
+    if(gr) {
+      treewalk(wr, +1);
+      if(wr == to_what) return sidecache[what] = -1;
+      }
     }
   }