xp)
      (pmatch exp
        ((if ,test ,then ,else)
         `(if ,test
              ,(consequent then)
              ,(consequent else)))
        (else
         `(make-primcall src ',(car exp)
                         ,(inline-args (cdr exp))))))
     ((symbol? exp)
      ;; assume locally bound
      exp)
     ((number? exp)
      `(make-const src ,exp))
     ((not exp)
      ;; failed match
      #f)
     (else (error "bad consequent yall" exp))))
  `(hashq-set! *primitive-expand-table*
               ',sym
               (match-lambda*
                ,@(let lp ((in clauses) (out '()))
                    (if (null? in)
                        (reverse (cons '(_ #f) out))
                        (lp (cddr in)
                            (cons `((src . ,(car in))
                                    ,(consequent (cadr in)))
                                  out)))))))

(define-primitive-expander zero? (x)
  (= x 0))

(define-primitive-expander positive? (x)
  (> x 0))

(define-primitive-expander negative? (x)
  (< x 0))

;; FIXME: All the code that uses `const?' is redundant with `peval'.

(define-primitive-expander 1+ (x)
  (+ x 1))

(define-primitive-expander 1- (x)
  (- x 1))

(define-primitive-expander +
  () 0
  (x) (values x)
  (x y) (+ x y)
  (x y z ... last) (+ (+ x y . z) last))

(define-primitive-expander *
  () 1
  (x) (values x)
  (x y z ... last) (* (* x y . z) last))
  
(define-primitive-expander -
  (x) (- 0 x)
  (x y) (- x y)
  (x y z ... last) (- (- x y . z) last))
  
(define-primitive-expander /
  (x) (/ 1 x)
  (x y z ... last) (/ (/ x y . z) last))
  
(define-primitive-expander logior
  () 0
  (x) (logior x 0)
  (x y) (logior x y)
  (x y z ... last) (logior (logior x y . z) last))

(define-primitive-expander logand
  () -1
  (x) (logand x -1)
  (x y) (logand x y)
  (x y z ... last) (logand (logand x y . z) last))

(define-primitive-expander caar (x) (car (car x)))
(define-primitive-expander cadr (x) (car (cdr x)))
(define-primitive-expander cdar (x) (cdr (car x)))
(define-primitive-expander cddr (x) (cdr (cdr x)))
(define-primitive-expander caaar (x) (car (car (car x))))
(define-primitive-expander caadr (x) (car (car (cdr x))))
(define-primitive-expander cadar (x) (car (cdr (car x))))
(define-primitive-expander caddr (x) (car (cdr (cdr x))))
(define-primitive-expander cdaar (x) (cdr (car (car x))))
(define-primitive-expander cdadr (x) (cdr (car (cdr x))))
(define-primitive-expander cddar (x) (cdr (cdr (car x))))
(define-primitive-expander cdddr (x) (cdr (cdr (cdr x))))
(define-primitive-expander caaaar (x) (car (car (car (car x)))))
(define-primitive-expander caaadr (x) (car (car (car (cdr x)))))
(define-primitive-expander caadar (x) (car (car (cdr (car x)))))
(define-primitive-expander caaddr (x) (car (car (cdr (cdr x)))))
(define-primitive-expander cadaar (x) (car (cdr (car (car x)))))
(define-primitive-expander cadadr (x) (car (cdr (car (cdr x)))))
(define-primitive-expander caddar (x) (car (cdr (cdr (car x)))))
(define-primitive-expander cadddr (x) (car (cdr (cdr (cdr x)))))
(define-primitive-expander cdaaar (x) (cdr (car (car (car x)))))
(define-primitive-expander cdaadr (x) (cdr (car (car (cdr x)))))
(define-primitive-expander cdadar (x) (cdr (car (cdr (car x)))))
(define-primitive-expander cdaddr (x) (cdr (car (cdr (cdr x)))))
(define-primitive-expander cddaar (x) (cdr (cdr (car (car x)))))
(define-primitive-expander cddadr (x) (cdr (cdr (car (cdr x)))))
(define-primitive-expander cdddar (x) (cdr (cdr (cdr (car x)))))
(define-primitive-expander cddddr (x) (cdr (cdr (cdr (cdr x)))))

(define-primitive-expander cons*
  (x) (values x)
  (x y) (cons x y)
  (x y . rest) (cons x (cons* y . rest)))

(define-primitive-expander acons (x y z)
  (cons (cons x y) z))

(define-primitive-expander call/cc (proc)
  (call-with-current-continuation proc))

(define-primitive-expander u8vector-ref (vec i)
  (bytevector-u8-ref vec i))
(define-primitive-expander u8vector-set! (vec i x)
  (bytevector-u8-set! vec i x))
(define-primitive-expander s8vector-ref (vec i)
  (bytevector-s8-ref vec i))
(define-primitive-expander s8vector-set! (vec i x)
  (bytevector-s8-set! vec i x))

(define-primitive-expander u16vector-ref (vec i)
  (bytevector-u16-native-ref vec (* i 2)))
(define-primitive-expander u16vector-set! (vec i x)
  (bytevector-u16-native-set! vec (* i 2) x))
(define-primitive-expander s16vector-ref (vec i)
  (bytevector-s16-native-ref vec (* i 2)))
(define-primitive-expander s16vector-set! (vec i x)
  (bytevector-s16-native-set! vec (* i 2) x))

(define-primitive-expander u32vector-ref (vec i)
  (bytevector-u32-native-ref vec (* i 4)))
(define-primitive-expander u32vector-set! (vec i x)
  (bytevector-u32-native-set! vec (* i 4) x))
(define-primitive-expander s32vector-ref (vec i)
  (bytevector-s32-native-ref vec (* i 4)))
(define-primitive-expander s32vector-set! (vec i x)
  (bytevector-s32-native-set! vec (* i 4) x))

(define-primitive-expander u64vector-ref (vec i)
  (bytevector-u64-native-ref vec (* i 8)))
(define-primitive-expander u64vector-set! (vec i x)
  (bytevector-u64-native-set! vec (* i 8) x))
(define-primitive-expander s64vector-ref (vec i)
  (bytevector-s64-native-ref vec (* i 8)))
(define-primitive-expander s64vector-set! (vec i x)
  (bytevector-s64-native-set! vec (* i 8) x))

(define-primitive-expander f32vector-ref (vec i)
  (bytevector-ieee-single-native-ref vec (* i 4)))
(define-primitive-expander f32vector-set! (vec i x)
  (bytevector-ieee-single-native-set! vec (* i 4) x))
(define-primitive-expander f32vector-ref (vec i)
  (bytevector-ieee-single-native-ref vec (* i 4)))
(define-primitive-expander f32vector-set! (vec i x)
  (bytevector-ieee-single-native-set! vec (* i 4) x))

(define-primitive-expander f64vector-ref (vec i)
  (bytevector-ieee-double-native-ref vec (* i 8)))
(define-primitive-expander f64vector-set! (vec i x)
  (bytevector-ieee-double-native-set! vec (* i 8) x))
(define-primitive-expander f64vector-ref (vec i)
  (bytevector-ieee-double-native-ref vec (* i 8)))
(define-primitive-expander f64vector-set! (vec i x)
  (bytevector-ieee-double-native-set! vec (* i 8) x))

(define (chained-comparison-expander prim-name)
  (case-lambda
    ((src) (make-const src #t))
    ((src a) #f)
    ((src a b) #f)
    ((src a b . rest)
     (let* ((b-sym (gensym "b"))
            (b* (make-lexical-ref src 'b b-sym)))
       (make-let src
                 '(b)
                 (list b-sym)
                 (list b)
                 (make-conditional src
                                   (make-primcall src prim-name (list a b*))
                                   (make-primcall src prim-name (cons b* rest))
                                   (make-const src #f)))))))

(for-each (lambda (prim-name)
            (hashq-set! *primitive-expand-table* prim-name
                        (chained-comparison-expander prim-name)))
          '(< > <= >= =))

(define (character-comparison-expander char< <)
  (lambda (src . args)
    (expand-primcall
     (make-primcall src <
                    (map (lambda (arg)
                           (make-primcall src 'char->integer (list arg)))
                         args)))))

(for-each (match-lambda
            ((char< . <)
             (hashq-set! *primitive-expand-table* char<
                         (character-comparison-expander char< <))))
          '((char<? . <)
            (char>? . >)
            (char<=? . <=)
            (char>=? . >=)
            (char=? . =)))

;; Appropriate for use with either 'eqv?' or 'equal?'.
(define (maybe-simplify-to-eq prim)
  (case-lambda
    ((src) (make-const src #t))
    ((src a) (make-const src #t))
    ((src a b)
     ;; Simplify cases where either A or B is constant.
     (define (maybe-simplify a b)
       (and (const? a)
            (let ((v (const-exp a)))
              (and (or (memq v '(#f #t () #nil))
                       (symbol? v)
                       (and (integer? v)
                            (exact? v)
                            (<= v most-positive-fixnum)
                            (>= v most-negative-fixnum)))
                   (make-primcall src 'eq? (list a b))))))
     (or (maybe-simplify a b) (maybe-simplify b a)))
    ((src a b . rest)
     (make-conditional src (make-primcall src prim (list a b))
                       (make-primcall src prim (cons b rest))
                       (make-const src #f)))
    (else #f)))

(hashq-set! *primitive-expand-table* 'eqv?   (maybe-simplify-to-eq 'eqv?))
(hashq-set! *primitive-expand-table* 'equal? (maybe-simplify-to-eq 'equal?))

(define (expand-chained-comparisons prim)
  (case-lambda
    ((src) (make-const src #t))
    ((src a)
     ;; (< x) -> (begin (< x 0) #t).  Residualizes side-effects from x
     ;; and, for numeric comparisons, checks that x is a number.
     (make-seq src
               (make-primcall src prim (list a (make-const src 0)))
               (make-const src #t)))
    ((src a b) #f)
    ((src a b . rest)
     (make-conditional src (make-primcall src prim (list a b))
                       (make-primcall src prim (cons b rest))
                       (make-const src #f)))
    (else #f)))

(for-each (lambda (prim)
            (hashq-set! *primitive-expand-table* prim
                        (expand-chained-comparisons prim)))
 '(< <= = >= > eq?))

(hashq-set! *primitive-expand-table*
            'call-with-prompt
            (case-lambda
              ((src tag thunk handler)
               (make-prompt src #f tag thunk handler))
              (else #f)))

(hashq-set! *primitive-expand-table*
            'abort-to-prompt*
            (case-lambda
              ((src tag tail-args)
               (make-abort src tag '() tail-args))
              (else #f)))
(hashq-set! *primitive-expand-table*
            'abort-to-prompt
            (case-lambda
              ((src tag . args)
               (make-abort src tag args (make-const #f '())))
              (else #f)))
