The unicity table was mixed with the bddNode table for now
apparent reason. After the hash of some node is computed,
bddnodes[hash] did only contain some random node (not the one
looked for) whose .hash member would point to the actual node with
this hash. So that's a two step lookup. With this patch, we sill
have a two step lookup, but the .hash member have been moved to a
separate array. A consequence is that bddNode is now 16-byte long
(instead of 20) so it will never span across two cache lines.
* src/kernel.h (bddNode): Remove the hash member, and move it...
(bddhash): ... as this new separate table.
* src/kernel.c, src/reorder.c: Adjust all code.
This avoids a library call to bdd_addref or bdd_delref.
* src/kernel.c (bdd_delref_nc, bdd_addref_nc): New function,
that work only on BDD that are not constant.
* src/cpext.cxx (bdd::operator=): Move...
* src/bdd.hh (bdd::operator=): ... here.
(bdd::bdd, bdd::~bdd, bdd::operator=): Inline the "is bdd constant"
check and call bdd_delref_nc/bdd_addref_nc only otherwise.
Fix some warnings reported by gcc.
* buddy/src/kernel.c (errorstrings): Mark these as const.
* buddy/src/reorder.c (reorder_gbc): Fix prototype.
(siftTestCmp): Add missing const in cast.
(bdd_reorder_auto): Actually call bdd_reorder_ready().
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.
Inline bdd_addref() and bdd_delref() to speedup BDD operations.
* src/kernel.c, src/kernel.h (bdd_addref, bdd_delref): Move these
functions and there associated global variables...
* src/bdd.c (bdd_error): ... and this function ...
* src/bdd.h (bdd_addref, bdd_delref, bdd_error): ...here so that
they can be inlined.
