commit be49af2216a127a82089366fdb5b335fb2f4e0c2
Author: Alexander Korotkov <a.korotkov@postgrespro.ru>
Date:   Tue Apr 10 14:27:55 2018 +0300

    Remove wrongly backpatched piece of code in cube.c
    
    Due to sloppy division of changes between f50c80dbb (which was not
    back-patched) and 563a053bd, this piece of code was wrongly backpatched to
    REL_10_STABLE and REL9_6_STABLE.  This code never causes real error because
    its condition is never satisfied, but it's a dead code, which needs to be
    removed.

diff --git a/contrib/cube/cube.c b/contrib/cube/cube.c
index e695a5e16c..b72053a1d5 100644
--- a/contrib/cube/cube.c
+++ b/contrib/cube/cube.c
@@ -1592,11 +1592,6 @@ cube_coord_llur(PG_FUNCTION_ARGS)
 		 */
 		result = 0.0;
 	}
-
-	/* Inverse value if needed */
-	if (inverse)
-		result = -result;
-
 	PG_RETURN_FLOAT8(result);
 }