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• Ubdd-constructors

Q-or

(q-or &rest args) constructs a UBDD representing the disjunction of its arguments.

In the logic,

(Q-OR)       = NIL
(Q-OR X)     = X
(Q-OR X Y)   = (Q-BINARY-OR X Y)
(Q-OR X Y Z) = (Q-BINARY-OR X (Q-BINARY-OR Y Z))

In the execution, we use the same sort of optimization as in q-and.

Definitions and Theorems

Function: q-binary-or

(defun q-binary-or (x y)
  (declare (xargs :guard t))
  (cond ((atom x)
         (if x t (if (atom y) (if y t nil) y)))
        ((atom y) (if y t x))
        ((hons-equal x y) x)
        (t (let ((l (q-binary-or (car x) (car y)))
                 (r (q-binary-or (cdr x) (cdr y))))
             (qcons l r)))))

Function: q-or-macro-logic-part

(defun q-or-macro-logic-part (args)
  (cond ((atom args) nil)
        ((atom (cdr args)) (car args))
        (t (cons 'q-binary-or
                 (cons (car args)
                       (cons (q-or-macro-logic-part (cdr args))
                             'nil))))))

Function: q-or-macro-exec-part

(defun q-or-macro-exec-part (args)
 (cond
  ((atom args) nil)
  ((atom (cdr args)) (car args))
  (t
   (cons
    'let
    (cons
     (cons (cons 'q-or-x-do-not-use-elsewhere
                 (cons (car args) 'nil))
           'nil)
     (cons
      (cons
       'if
       (cons
        '(eq t q-or-x-do-not-use-elsewhere)
        (cons
         't
         (cons
          (cons
           'prog2$
           (cons
            '(last-chance-wash-memory)
            (cons
                 (cons 'q-binary-or
                       (cons 'q-or-x-do-not-use-elsewhere
                             (cons (q-or-macro-exec-part (cdr args))
                                   'nil)))
                 'nil)))
          'nil))))
      'nil))))))

Function: q-or-macro-fn

(defun q-or-macro-fn (args)
 (cond
  ((atom args) nil)
  ((atom (cdr args)) (car args))
  (t
   (mv-let (cheap expensive)
           (cheap-and-expensive-arguments args)
    (if (not expensive)
        (q-or-macro-logic-part cheap)
     (let ((reordered-args (append cheap expensive)))
      (cons
       'mbe
       (cons ':logic
             (cons (q-or-macro-logic-part reordered-args)
                   (cons ':exec
                         (cons (q-or-macro-exec-part reordered-args)
                               'nil)))))))))))

Theorem: ubddp-of-q-or

(defthm ubddp-of-q-or
  (implies (and (force (ubddp x))
                (force (ubddp y)))
           (equal (ubddp (q-or x y)) t)))

Theorem: eval-bdd-of-q-or

(defthm eval-bdd-of-q-or
  (equal (eval-bdd (q-or x y) values)
         (or (eval-bdd x values)
             (eval-bdd y values))))

Theorem: canonicalize-q-or

(defthm canonicalize-q-or
  (implies (and (force (ubddp x))
                (force (ubddp y)))
           (equal (q-or x y) (q-ite x t y))))

Theorem: q-or-of-nil-slow

(defthm q-or-of-nil-slow
  (and (equal (q-or nil x)
              (if (consp x) x (if x t nil)))
       (equal (q-or x nil)
              (if (consp x) x (if x t nil)))))

Theorem: q-or-of-nil-aggressive

(defthm q-or-of-nil-aggressive
  (implies (force (ubddp x))
           (and (equal (q-or nil x) x)
                (equal (q-or x nil) x))))

Theorem: q-or-of-t

(defthm q-or-of-t
  (and (equal (q-or t x) t)
       (equal (q-or x t) t)))

Theorem: q-or-symmetric

(defthm q-or-symmetric
  (equal (q-or x y) (q-or y x)))

Function: q-binary-or-memoize-condition

(defun q-binary-or-memoize-condition (x y)
  (declare (ignorable x y)
           (xargs :guard 't))
  (and (consp x) (consp y)))

Theorem: q-or-of-self-slow

(defthm q-or-of-self-slow
  (equal (q-or x x)
         (if (consp x) x (if x t nil))))

Theorem: q-or-of-self-aggressive

(defthm q-or-of-self-aggressive
  (implies (force (ubddp x))
           (equal (q-or x x) x)))