diff --git a/buddy/ChangeLog b/buddy/ChangeLog
index cfe5b9e3f..7b0cf0d1f 100644
--- a/buddy/ChangeLog
+++ b/buddy/ChangeLog
@@ -1,3 +1,11 @@
+2011-04-04  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
+
+	Remove more sanity checks when NDEBUG is set.
+
+	* src/kernel.h (CHECKnc): New macro.
+	* src/kernel.c (bdd_var, bdd_low, bdd_high, bdd_ithvar,
+	bdd_nithvar): Use it.
+
 2011-04-03  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
 
 	* src/kernel.h (CHECK, CHECKa, CHECKn): Disable if NDEBUG is set.
diff --git a/buddy/src/kernel.c b/buddy/src/kernel.c
index 5a430bb00..36492d0af 100644
--- a/buddy/src/kernel.c
+++ b/buddy/src/kernel.c
@@ -874,11 +874,13 @@ RETURN  {* The I'th variable on succes, otherwise the constant false bdd *}
 ALSO {* bdd\_setvarnum, bdd\_nithvar, bddtrue, bddfalse *} */
 BDD bdd_ithvar(int var)
 {
+#ifndef NDEBUG
    if (var < 0  ||  var >= bddvarnum)
    {
       bdd_error(BDD_VAR);
       return bddfalse;
    }
+#endif
 
    return bddvarset[var*2];
 }
@@ -900,11 +902,13 @@ ALSO    {* bdd\_setvarnum, bdd\_ithvar, bddtrue, bddfalse *}
 */
 BDD bdd_nithvar(int var)
 {
+#ifndef NDEBUG
    if (var < 0  ||  var >= bddvarnum)
    {
       bdd_error(BDD_VAR);
       return bddfalse;
    }
+#endif
 
    return bddvarset[var*2+1];
 }
@@ -937,10 +941,8 @@ RETURN  {* The variable number. *}
 int bdd_var(BDD root)
 {
    CHECK(root);
-   if (root < 2)
-      return bdd_error(BDD_ILLBDD);
-
-   return (bddlevel2var[LEVEL(root)]);
+   CHECKnc(root);
+   return bddlevel2var[LEVEL(root)];
 }
 
 
@@ -956,10 +958,8 @@ ALSO    {* bdd\_high *}
 BDD bdd_low(BDD root)
 {
    CHECK(root);
-   if (root < 2)
-      return bdd_error(BDD_ILLBDD);
-
-   return (LOW(root));
+   CHECKnc(root);
+   return LOW(root);
 }
 
 
@@ -975,10 +975,8 @@ ALSO    {* bdd\_low *}
 BDD bdd_high(BDD root)
 {
    CHECK(root);
-   if (root < 2)
-      return bdd_error(BDD_ILLBDD);
-
-   return (HIGH(root));
+   CHECKnc(root);
+   return HIGH(root);
 }
 
 
diff --git a/buddy/src/kernel.h b/buddy/src/kernel.h
index b024dcc9b..05cb98c13 100644
--- a/buddy/src/kernel.h
+++ b/buddy/src/kernel.h
@@ -58,6 +58,7 @@
 #define CHECK(r) (void)(r);
 #define CHECKa(r,a) (void)(r); (void)(a);
 #define CHECKn(r) (void)(r);
+#define CHECKnc(r) (void)(r);
 #else
    /* Sanity check argument and return eventual error code */
 #define CHECK(r)\
@@ -79,6 +80,12 @@
      { bdd_error(BDD_ILLBDD); return; }\
    else if (r >= 2 && LOW(r) == -1)\
      { bdd_error(BDD_ILLBDD); return; }
+
+   /* r is non-constant */
+#define CHECKnc(r)\
+   if (root < 2) \
+      return bdd_error(BDD_ILLBDD)
+
 #endif
 
 /*=== SEMI-INTERNAL TYPES ==============================================*/
@@ -220,7 +227,7 @@ extern void   bdd_fdd_done(void);
 
 extern void   bdd_reorder_init(void);
 extern void   bdd_reorder_done(void);
-extern int    bdd_reorder_ready(void);
+extern int    bdd_reorder_ready(void) __purefn;
 extern void   bdd_reorder_auto(void);
 extern int    bdd_reorder_vardown(int);
 extern int    bdd_reorder_varup(int);