From c0176ad738624ef20839fa56dde4a8cfa332bcb4 Mon Sep 17 00:00:00 2001
From: Sei Lisa <sei-lisa@email.fake>
Date: Fri, 27 Oct 2017 11:03:35 +0200
Subject: [PATCH] Fix order change in comparisons when one side is not SEF.

The comment was wrong anyway. If one side changes x and the other side uses x, then order is still important, no matter whether one side is SEF.

But the reversal is safe when one side is a constant, so we still perform it, to enable optimization of some important cases.
---
 lslopt/lslfoldconst.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lslopt/lslfoldconst.py b/lslopt/lslfoldconst.py
index 05595e8..f742c1d 100644
--- a/lslopt/lslfoldconst.py
+++ b/lslopt/lslfoldconst.py
@@ -1158,10 +1158,11 @@ class foldconst(object):
                 self.FoldTree(parent, index)
                 return
 
-            if nt == '>':
+            if nt == '>' and ('SEF' in child[0] and 'SEF' in child[1]
+                or child[0]['nt'] == 'CONST' or child[1]['nt'] == 'CONST'
+               ):
                 # Invert the inequalities to avoid doubling the cases to check.
                 # a>b  ->   b<a
-                # FIXME: This is only possible if at most one is non-SEF.
                 nt = node['nt'] = '<'
                 child[1], child[0] = child[0], child[1]
                 # fall through to check for '<'