;;;; This file contains stuff that implements the portable IR1
;;;; semantics of type tests and coercion. The main thing we do is
;;;; convert complex type operations into simpler code that can be
;;;; compiled inline.

;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.

(in-package "SB-C")

;;;; type predicate translation
;;;;
;;;; We maintain a bidirectional association between type predicates
;;;; and the tested type. The presence of a predicate in this
;;;; association implies that it is desirable to implement tests of
;;;; this type using the predicate. These are either predicates that
;;;; the back end is likely to have special knowledge about, or
;;;; predicates so complex that the only reasonable implentation is
;;;; via function call.
;;;;
;;;; Some standard types (such as ATOM) are best tested by letting the
;;;; TYPEP source transform do its thing with the expansion. These
;;;; types (and corresponding predicates) are not maintained in this
;;;; association. In this case, there need not be any predicate
;;;; function unless it is required by the Common Lisp specification.
;;;;
;;;; The mapping between predicates and type structures is considered
;;;; part of the backend; different backends can support different
;;;; sets of predicates.

;;; Establish an association between the type predicate NAME and the
;;; corresponding TYPE. This causes the type predicate to be
;;; recognized for purposes of optimization.
(defmacro define-type-predicate (name type)
  `(%define-type-predicate ',name ',type))
(defun %define-type-predicate (name specifier)
  (let ((type (specifier-type specifier)))
    (setf (gethash name *backend-predicate-types*) type)
    (setf *backend-type-predicates*
          (cons (cons type name)
                (remove name *backend-type-predicates*
                        :key #'cdr)))
    (%deftransform name nil '(function (t) *) #'fold-type-predicate)))

;;;; IR1 transforms

;;; If we discover the type argument is constant during IR1
;;; optimization, then give the source transform another chance. The
;;; source transform can't pass, since we give it an explicit
;;; constant. At worst, it will convert to %TYPEP, which will prevent
;;; spurious attempts at transformation (and possible repeated
;;; warnings.)
(deftransform typep ((object type &optional env) * * :node node)
  (unless (constant-lvar-p type)
    (give-up-ir1-transform "can't open-code test of non-constant type"))
  (unless (unsupplied-or-nil env)
    (give-up-ir1-transform "environment argument present and not null"))
  (multiple-value-bind (expansion fail-p)
      (source-transform-typep 'object (lvar-value type))
    (if fail-p
        (abort-ir1-transform)
        expansion)))

;;; If the lvar OBJECT definitely is or isn't of the specified
;;; type, then return T or NIL as appropriate. Otherwise quietly
;;; GIVE-UP-IR1-TRANSFORM.
(defun ir1-transform-type-predicate (object type node)
  (declare (type lvar object) (type ctype type))
  (let ((otype (lvar-type object)))
    (cond ((not (types-equal-or-intersect otype type))
           (return-from ir1-transform-type-predicate nil))
          ((csubtypep otype type)
           (return-from ir1-transform-type-predicate t))
          ((eq type *empty-type*)
           (return-from ir1-transform-type-predicate nil)))
    (let ((intersect (type-intersection2 type otype)))
      ;; I guess the theory here is that an intersection type
      ;; is never a singleton, because if we could see that it was
      ;; a singleton, it wouldn't be an intersection.
      (when (and intersect (not (intersection-type-p intersect)))
        (multiple-value-bind (constantp value) (type-singleton-p intersect)
          (when constantp
            (return-from ir1-transform-type-predicate `(eql object ',value)))))
      ;; If the object type is known to be (OR NULL <type>),
      ;; it is almost always cheaper to test for not EQ to NIL.
      ;; There is one exception:
      ;;  - FIXNUMP is possibly cheapear than comparison to NIL, or definitely
      ;;    not worse. For x86, NIL is a 4-byte immediate operand,
      ;;    for lack of a null-tn register. FIXNUM-TAG-MASK is only 1 byte.
      (when (type= otype (type-union (specifier-type 'null) type))
        (let ((difference (type-difference type (specifier-type 'null))))
          (unless (type= difference (specifier-type 'fixnum))
            (return-from  ir1-transform-type-predicate `(not (null object))))))
      (cond ((typep type 'alien-type-type)
                    ;; We don't transform alien type tests until here, because
                    ;; once we do that the rest of the type system can no longer
                    ;; reason about them properly -- so we'd miss out on type
                    ;; derivation, etc.
                    (delay-ir1-transform node :optimize)
                    (let ((alien-type (alien-type-type-alien-type type)))
                      ;; If it's a lisp-rep-type, the CTYPE should be one already.
                      (aver (not (compute-lisp-rep-type alien-type)))
                      `(sb-alien::alien-value-typep object ',alien-type)))
            (t
             (give-up-ir1-transform))))))

;;; Flush %TYPEP tests whose result is known at compile time.
(deftransform %typep ((object type) * * :node node)
  (unless (constant-lvar-p type)
    (give-up-ir1-transform))
  (ir1-transform-type-predicate
   object
   (ir1-transform-specifier-type (lvar-value type))
   node))

;;; This is the IR1 transform for simple type predicates. It checks
;;; whether the single argument is known to (not) be of the
;;; appropriate type, expanding to T or NIL as appropriate.
(deftransform fold-type-predicate ((object) * * :node node :defun-only t)
  (let ((ctype (gethash (leaf-source-name
                         (ref-leaf
                          (lvar-uses
                           (basic-combination-fun node))))
                        *backend-predicate-types*)))
    (aver ctype)
    (ir1-transform-type-predicate object ctype node)))

;;; If FIND-CLASSOID is called on a constant class, locate the
;;; CLASSOID-CELL at load time.
(deftransform find-classoid ((name) ((constant-arg symbol)) *)
  (let* ((name (lvar-value name))
         (cell (find-classoid-cell name :create t)))
    `(or (classoid-cell-classoid ',cell)
         (error "Class not yet defined: ~S" name))))

(defoptimizer (%typep-wrapper constraint-propagate-if)
    ((test-value variable type) node gen)
  (declare (ignore test-value gen))
  (aver (constant-lvar-p type))
  (let ((type (lvar-value type)))
    (values variable (if (ctype-p type)
                         type
                         (handler-case (careful-specifier-type type)
                           (t () nil))))))

(deftransform %typep-wrapper ((test-value variable type) * * :node node)
  (aver (constant-lvar-p type))
  (if (constant-lvar-p test-value)
      `',(lvar-value test-value)
      (let* ((type (lvar-value type))
             (type (if (ctype-p type)
                       type
                       (handler-case (careful-specifier-type type)
                         (t () nil))))
             (value-type (lvar-type variable)))
        (cond ((not type)
               'test-value)
              ((csubtypep value-type type)
               t)
              ((not (types-equal-or-intersect value-type type))
               nil)
              (t
               (delay-ir1-transform node :constraint)
               'test-value)))))

(deftransform %type-constraint ((x type) * * :node node)
  (delay-ir1-transform node :constraint)
  nil)

(defoptimizer (%type-constraint constraint-propagate) ((x type) node gen)
  (declare (ignore node))
  (let ((var (ok-lvar-lambda-var x gen)))
    (when var
      (let ((type (lvar-value type)))
        (list (list 'typep var
                    (if (ctype-p type)
                        type
                        (handler-case (careful-specifier-type type)
                          (t () nil)))
                    nil))))))

;;;; standard type predicates, i.e. those defined in package COMMON-LISP,
;;;; plus at least one oddball (%INSTANCEP)
;;;;
;;;; Various other type predicates (e.g. low-level representation
;;;; stuff like SIMPLE-ARRAY-SINGLE-FLOAT-P) are defined elsewhere.

;;; FIXME: This function is only called once, at top level. Why not
;;; just expand all its operations into toplevel code?
(defun !define-standard-type-predicates ()
  (define-type-predicate arrayp array)
  ; (The ATOM predicate is handled separately as (NOT CONS).)
  (define-type-predicate bit-vector-p bit-vector)
  (define-type-predicate characterp character)
  #+(and sb-unicode (or x86-64 arm64)) ;; others have a source-transform
  (define-type-predicate base-char-p base-char)
  (define-type-predicate compiled-function-p compiled-function)
  (define-type-predicate complexp complex)
  (define-type-predicate complex-rational-p (complex rational))
  (define-type-predicate complex-float-p (complex float))
  (define-type-predicate consp cons)
  (define-type-predicate floatp float)
  (define-type-predicate functionp function)
  (define-type-predicate integerp integer)
  (define-type-predicate keywordp keyword)
  (define-type-predicate listp list)
  (define-type-predicate null null)
  (define-type-predicate numberp number)
  (define-type-predicate rationalp rational)
  (define-type-predicate realp real)
  (define-type-predicate sequencep sequence)
  (define-type-predicate extended-sequence-p extended-sequence)
  (define-type-predicate simple-bit-vector-p simple-bit-vector)
  (define-type-predicate simple-string-p simple-string)
  (define-type-predicate simple-vector-p simple-vector)
  (define-type-predicate stringp string)
  (define-type-predicate %instancep instance)
  (define-type-predicate simple-fun-p simple-fun)
  (define-type-predicate closurep closure)
  (define-type-predicate funcallable-instance-p funcallable-instance)
  (define-type-predicate symbolp symbol)
  (define-type-predicate vectorp vector))
(!define-standard-type-predicates)

;;;; transforms for type predicates not implemented primitively
;;;;
;;;; See also VM dependent transforms.

(define-source-transform atom (x)
  `(not (consp ,x)))

#+(and sb-unicode (not (or x86-64 arm64)))
(define-source-transform base-char-p (x)
  `(typep ,x 'base-char))
;; CONS is implemented as (and list (not (eql nil))) where the 'and' is
;; built-in to the consp vop. Reduce to just LISTP if possible.
(deftransform consp ((x) ((not null)) * :important nil)
  '(listp x))

;;; If X is known non-nil, then testing SYMBOLP can skip the "= NIL" part.
(deftransform symbolp ((x) ((not null)) * :important nil)
  '(non-null-symbol-p x))
(deftransform non-null-symbol-p ((object) (symbol) * :important nil)
  `(not (eq object nil)))
;;; CLHS: http://www.lispworks.com/documentation/HyperSpec/Body/t_symbol.htm#symbol
;;;   "The consequences are undefined if an attempt is made to alter the home package
;;;    of a symbol external in the COMMON-LISP package or the KEYWORD package."
;;; Therefore, we can constant-fold if the symbol-package is one of those two.
;;; Interestingly, we don't need any transform for (NOT SYMBOL)
;;; because IR1-TRANSFORM-TYPE-PREDICATE knows that the intersection of the type
;;; implied by KEYWORDP with any type that does not intersect SYMBOL is NIL.
(deftransform keywordp ((x) ((constant-arg symbol)))
  (let ((pkg (sb-xc:symbol-package (lvar-value x))))
    (cond ((eq pkg *cl-package*) 'nil)
          ((eq pkg *keyword-package*) 't)
          (t (give-up-ir1-transform)))))

;;;; TYPEP source transform

;;; Return a form that tests the variable N-OBJECT for being in the
;;; binds specified by TYPE. BASE is the name of the base type, for
;;; declaration. We make SAFETY locally 0 to inhibit any checking of
;;; this assertion.
(defun transform-numeric-bound-test (n-object type base)
  (declare (type numeric-type type))
  (let ((low (numeric-type-low type))
        (high (numeric-type-high type)))
    `(locally
       (declare (optimize (safety 0)))
       (and ,@(when low
                (if (consp low)
                    `((> (truly-the ,base ,n-object) ,(car low)))
                    `((>= (truly-the ,base ,n-object) ,low))))
            ,@(when high
                (if (consp high)
                    `((< (truly-the ,base ,n-object) ,(car high)))
                    `((<= (truly-the ,base ,n-object) ,high))))))))

;;; Do source transformation of a test of a known numeric type. We can
;;; assume that the type doesn't have a corresponding predicate, since
;;; those types have already been picked off. In particular, CLASS
;;; must be specified, since it is unspecified only in NUMBER and
;;; COMPLEX. Similarly, we assume that COMPLEXP is always specified.
;;;
;;; For non-complex types, we just test that the number belongs to the
;;; base type, and then test that it is in bounds. When CLASS is
;;; INTEGER, we check to see whether the range is no bigger than
;;; FIXNUM. If so, we check for FIXNUM instead of INTEGER. This allows
;;; us to use fixnum comparison to test the bounds.
;;;
;;; For complex types, we must test for complex, then do the above on
;;; both the real and imaginary parts. When CLASS is float, we need
;;; only check the type of the realpart, since the format of the
;;; realpart and the imagpart must be the same.
(defun source-transform-numeric-typep (object type)
  (let* ((class (numeric-type-class type))
         (base (ecase class
                 (integer (containing-integer-type
                           (if (numeric-type-complexp type)
                               (modified-numeric-type type
                                                      :complexp :real)
                               type)))
                 (rational 'rational)
                 (float (or (numeric-type-format type) 'float))
                 ((nil) 'real)))
         (low (numeric-type-low type))
         (high (numeric-type-high type)))
    (ecase (numeric-type-complexp type)
      (:real
       (cond ((and (eql (numeric-type-class type) 'integer)
                   (and (fixnump low)
                        (fixnump high)
                        #+(or x86 x86-64 arm arm64)
                        (/= low 0)
                        (< (- high low) 2)))
              ;; The fixnum-mod-p case is worse than just EQ testing with
              ;; only 2 values in the range. (INTEGER 1 2) would have become
              ;;   (and (not (eq x 0)) (fixnump x) (not (> x 2))).
              ;; If exactly 1 value, it should have been picked off by TYPE-SINGLETON-P
              ;; in %SOURCE-TRANSFORM-TYPEP, but even if it wasn't,
              ;; the OR will drop out due to constraint propagation.
              `(or (eq ,object ,low) (eq ,object ,high)))
             #+(or x86 x86-64 arm arm64) ;; Not implemented elsewhere yet
             ((and (eql (numeric-type-class type) 'integer)
                   (or (eql low 0) (eql low 1))
                   (fixnump (numeric-type-high type)))
              (let ((mod-p
                      `(fixnum-mod-p ,object ,(numeric-type-high type))))
                (if (eql low 1)
                    `(and (not (eq ,object 0))
                          ,mod-p)
                    mod-p)))
             (t
              `(and (typep ,object ',base)
                    ,(transform-numeric-bound-test object type base)))))
      (:complex
       `(and (complexp ,object)
             ,(once-only ((n-real `(realpart (truly-the complex ,object)))
                          (n-imag `(imagpart (truly-the complex ,object))))
                `(progn
                   ,n-imag ; ignorable
                   (and (typep ,n-real ',base)
                        ,@(when (eq class 'integer)
                            `((typep ,n-imag ',base)))
                        ,(transform-numeric-bound-test n-real type base)
                        ,(transform-numeric-bound-test n-imag type
                                                       base)))))))))

;;; Do the source transformation for a test of a hairy type.
;;; SATISFIES is converted into the obvious. Otherwise, we convert
;;; to CACHED-TYPEP an possibly print an efficiency note.
(defun source-transform-hairy-typep (object type)
  (declare (type hairy-type type))
  (let ((spec (hairy-type-specifier type)))
    (cond ((and (unknown-type-p type)
                (symbolp spec)
                (eq (info :type :kind spec) :forthcoming-defclass-type))
           ;; Knowing that it was DEFCLASSed is enough to emit a CLASSOID-CELL-TYPEP test.
           ;; Combinators involving this - e.g. (OR A-NEW-CLASS OTHER-CLASS) -
           ;; are handled correctly, because we don't punt on everything in the expression
           ;; as soon as any unknown is present.
           `(classoid-cell-typep ,(find-classoid-cell spec :create t) ,object))
          ((unknown-type-p type)
           #+(and sb-xc-host (not sb-devel))
           (warn "can't open-code test of unknown type ~S"
                 (type-specifier type))
           ;; This is not a policy-based decision to notify here,
           ;; because it is _ALWAYS_ questionable style imho to refer to unknown types.
           ;; Unfortunately, people love to suppress COMPILER-NOTE because SBCL produces
           ;; far too many of those for low-level things like untagged-SAP-to-tagged-SAP.
           ;; So we could opt to STYLE-WARN, which is, in this case, perhaps more severe
           ;; than we'd like?
           ;; I guess we're just going to have to say that if you've muffled too may
           ;; kinds of NOTEs, that's on you.
           #-sb-xc-host (compiler-notify 'unknown-typep-note
                                         :format-control "can't open-code test of unknown type ~S"
                                         :format-arguments (list (type-specifier type)))
           `(let ((object ,object)
                  (cache (load-time-value (cons #'sb-kernel::cached-typep ',spec)
                                          t)))
              (truly-the (values t &optional)
                         (funcall (truly-the function (car (truly-the cons cache)))
                                  cache object))))
          (t
           (ecase (first spec)
             (satisfies
              (let* ((name (second spec))
                     (expansion (fun-name-inline-expansion name)))
                ;; Lambda without lexenv can easily be handled here.
                ;; This fixes the issue that LEGAL-FUN-NAME-P which is
                ;; just a renaming of VALID-FUNCTION-NAME-P would not
                ;; be inlined when testing the FUNCTION-NAME type.
                `(if ,(if (and (typep expansion '(cons (eql lambda)))
                               (not (fun-lexically-notinline-p name)))
                          `(,expansion ,object)
                          `(funcall (global-function ,name) ,object))
                     t nil))))))))

(defun source-transform-negation-typep (object type)
  (declare (type negation-type type))
  (let ((spec (type-specifier (negation-type-type type))))
    `(not (typep ,object ',spec))))

;;; Check the type of a group of equally specialized but of
;;; different length simple arrays once
(defun group-vector-type-length-tests (object types)
  (let (groups
        any-grouped)
    (loop for type in types
          do
          (if (and (array-type-p type)
                   (not (array-type-complexp type))
                   (typep (array-type-dimensions type) '(cons integer null))
                   (or (eq (array-type-element-type type) *wild-type*)
                       (neq (array-type-specialized-element-type type) *wild-type*)))
              (push type
                    (getf groups
                          (array-type-specialized-element-type type)))
              (push type (getf groups :other))))
    (loop for (el-type types) on groups by #'cddr
          do
          (cond ((eq el-type :other))
                ((> (length types) 1)
                 (setf any-grouped t))
                (t
                 (push (car types)
                       (getf groups :other)))))
    (when any-grouped
      (let ((other (getf groups :other)))
        `(or
          ,@(loop for (el-type types) on groups by #'cddr
                  when (and (neq el-type :other)
                            (> (length types) 1))
                  collect `(and (typep ,object
                                       '(simple-array ,(type-specifier el-type) (*)))
                                (typep (vector-length
                                        (truly-the (simple-array * (*)) ,object))
                                       '(member ,@(loop for type in types
                                                        collect (car (array-type-dimensions type)))))))
          ,@(and
             other
             `((typep ,object '(or ,@(mapcar #'type-specifier other))))))))))

;;; Test the length of multiple arrays types once
(defun group-vector-length-type-tests (object types)
  (let (groups
        any-grouped)
    (loop for type in types
          do
          (if (and (array-type-p type)
                   (typep (array-type-dimensions type) '(cons integer null)))
              (push type (getf groups (car (array-type-dimensions type))))
              (push type (getf groups :other))))
    (loop for (length types) on groups by #'cddr
          do
          (cond ((eq length :other))
                ((> (length types) 1)
                 (setf any-grouped t))
                (t
                 (push (car types)
                       (getf groups :other)))))
    (when any-grouped
      (let ((other (getf groups :other)))
        `(or
          ,@(loop for (length types) on groups by #'cddr
                  for any-complex = nil
                  for any-simple = nil
                  when (and (neq length :other)
                            (> (length types) 1))
                  collect `(and (typep ,object
                                       '(or
                                         ,@(loop for type in types
                                                 for complex = (array-type-complexp type)
                                                 do (cond (complex
                                                           (setf any-complex t)
                                                           (when (eq complex :maybe)
                                                             (setf any-simple t)))
                                                          (t
                                                           (setf any-simple t)))

                                                 collect
                                                 (type-specifier
                                                  (make-array-type '(*)
                                                                   :complexp complex
                                                                   :element-type
                                                                   (array-type-element-type type)
                                                                   :specialized-element-type
                                                                   (array-type-specialized-element-type type))))))
                                ,(cond
                                   ((not any-complex)
                                    `(= (vector-length (truly-the (simple-array * (*)) ,object))
                                        ,length))
                                   ((not any-simple)
                                    `(= (%array-dimension (truly-the vector ,object) 0)
                                        ,length))
                                   (t
                                    `(if (array-header-p (truly-the vector ,object))
                                         (= (%array-dimension (truly-the vector ,object) 0)
                                            ,length)
                                         (= (vector-length (truly-the vector ,object))
                                            ,length))))))
          ,@(and
             other
             `((typep ,object '(or ,@(mapcar #'type-specifier other))))))))))

;;; Do source transformation for TYPEP of a known union type. If a
;;; union type contains LIST, then we pull that out and make it into a
;;; single LISTP call.
(defun source-transform-union-typep (object type)
  (let* ((types (union-type-types type))
         (type-cons (specifier-type 'cons))
         (type-symbol (specifier-type 'symbol))
         (mtype (find-if #'member-type-p types))
         (members (when mtype (member-type-members mtype))))
    (cond ((and mtype
                (memq nil members)
                (memq type-cons types))
           `(or (listp ,object)
                (typep ,object
                       '(or ,@(mapcar #'type-specifier
                               (remove type-cons
                                (remove mtype types)))
                         (member ,@(remove nil members))))))
          ((and (memq type-cons types)
                (memq type-symbol types))
           `(or (listp ,object)
                (non-null-symbol-p ,object)
                (typep ,object
                       '(or ,@(mapcar #'type-specifier
                               (remove type-cons
                                (remove type-symbol types)))))))
          ((group-vector-type-length-tests object types))
          ((group-vector-length-type-tests object types))
          (t
           (multiple-value-bind (widetags more-types)
               (sb-kernel::widetags-from-union-type types)
             (multiple-value-bind (predicate more-union-types)
                 (split-union-type-tests type)
               (cond ((and predicate
                           (< (length more-union-types)
                              (length more-types)))
                      `(or (,predicate ,object)
                           (typep ,object '(or ,@(mapcar #'type-specifier more-union-types)))))
                     (widetags
                      `(or (%other-pointer-subtype-p ,object ',widetags)
                           (typep ,object '(or ,@(mapcar #'type-specifier more-types)))))
                     (t
                      `(or
                        ,@(mapcar (lambda (x)
                                    `(typep ,object ',(type-specifier x)))
                                  more-types))))))))))

;;; Do source transformation for TYPEP of a known intersection type.
(defun source-transform-intersection-typep (object type)
  `(and ,@(mapcar (lambda (x)
                    `(typep ,object ',(type-specifier x)))
                  (intersection-type-types type))))

;;; If necessary recurse to check the cons type.
(defun source-transform-cons-typep (object type)
  (let* ((car-type (cons-type-car-type type))
         (cdr-type (cons-type-cdr-type type))
         (car-test-p (not (type= car-type *universal-type*)))
         (cdr-test-p (not (type= cdr-type *universal-type*))))
    (if (and (not car-test-p) (not cdr-test-p))
        `(consp ,object)
        ;; CONSP can be safely weakened to LISTP if either of the CAR
        ;; or CDR test (or both) can distinguish LIST from CONS
        ;; by never returning T when given an input of NIL.
        (labels ((safely-weakened (ctype)
                   (typecase ctype
                     (member-type
                      (not (member nil (member-type-members ctype))))
                     (classoid
                      ;; can't weaken if the specifier is (CONS SYMBOL)
                      (not (ctypep nil ctype)))
                     ;; these are disjoint from NIL
                     ((or cons-type numeric-type array-type character-set-type)
                      t)
                     (intersection-type
                      ;; at least one of them must not spuriously return T
                      (some #'safely-weakened (compound-type-types ctype)))
                     (union-type
                      ;; require that none spuriously return T
                      (every #'safely-weakened (compound-type-types ctype)))
                     (hairy-type
                      ;; hack - (CONS KEYWORD) is weakenable
                      ;; because NIL is not a keyword.
                      (equal (hairy-type-specifier ctype)
                             '(satisfies keywordp))))))
          (let ((car-test
                  (and car-test-p
                       `((typep (car ,object) ',(type-specifier car-type)))))
                (cdr-test
                  (and cdr-test-p
                       `((typep (cdr ,object) ',(type-specifier cdr-type))))))
            ;; Being paranoid, perform the safely weakenable test first
            ;; so that the other part doesn't execute on an object that
            ;; it would not have gotten, were the CONSP test not weakened.
            (cond ((and car-test-p (safely-weakened car-type))
                   `(and (listp ,object) ,@car-test ,@cdr-test))
                  ((and cdr-test-p (safely-weakened cdr-type))
                   `(and (listp ,object) ,@cdr-test ,@car-test))
                  (t
                   `(and (consp ,object) ,@car-test ,@cdr-test))))))))

(defun source-transform-character-set-typep (object type)
  (let ((pairs (character-set-type-pairs type)))
    (or (and (= (length pairs) 1)
             (= (caar pairs) 0)
             (cond
               #+(and sb-unicode (or x86-64 arm64))
               ((= (cdar pairs) (1- base-char-code-limit))
                `(base-char-p ,object))
               ((= (cdar pairs) (1- char-code-limit))
                `(characterp ,object))))
        (let ((n-code (sb-xc:gensym "CODE")))
          `(and (characterp ,object)
                (let ((,n-code (char-code ,object)))
                  (or
                   ,@(loop for pair in pairs
                           collect
                           `(<= ,(car pair) ,n-code ,(cdr pair))))))))))

#+sb-simd-pack
(defun source-transform-simd-pack-typep (object type)
  (if (type= type (specifier-type 'simd-pack))
      `(simd-pack-p ,object)
      (let ((n-tag (sb-xc:gensym "TAG")))
        `(and
          (simd-pack-p ,object)
          (let ((,n-tag (%simd-pack-tag ,object)))
            (or ,@(loop
                    for type in (simd-pack-type-element-type type)
                    for index = (position type *simd-pack-element-types*)
                    collect `(eql ,n-tag ,index))))))))

#+sb-simd-pack-256
(defun source-transform-simd-pack-256-typep (object type)
  (if (type= type (specifier-type 'simd-pack-256))
      `(simd-pack-256-p ,object)
      (let ((n-tag (sb-xc:gensym "TAG")))
        `(and
          (simd-pack-256-p ,object)
          (let ((,n-tag (%simd-pack-256-tag ,object)))
            (or ,@(loop
                    for type in (simd-pack-256-type-element-type type)
                    for index = (position type *simd-pack-element-types*)
                    collect `(eql ,n-tag ,index))))))))

;;; Return the predicate and type from the most specific entry in
;;; *TYPE-PREDICATES* that is a supertype of TYPE.
(defun find-supertype-predicate (type)
  (declare (type ctype type))
  (let ((res nil)
        (res-type nil))
    (dolist (x *backend-type-predicates*)
      (let ((stype (car x)))
        (when (and (csubtypep type stype)
                   (or (not res-type)
                       (csubtypep stype res-type)))
          (setq res-type stype)
          (setq res (cdr x)))))
    (values res res-type)))

;;; Return forms to test that OBJ has the rank and dimensions
;;; specified by TYPE, where STYPE is the type we have checked against
;;; (which is the same but for dimensions and element type).
;;;
;;; Secondary return value is true if passing the generated tests implies that
;;; the array has a header.
(defun test-array-dimensions (original-obj type stype
                              simple-array-header-p)
  (declare (type array-type type stype))
  (let ((obj `(truly-the ,(type-specifier stype) ,original-obj))
        (dims (array-type-dimensions type))
        (header-test (if simple-array-header-p
                         `(simple-array-header-p ,original-obj)
                         `(array-header-p ,original-obj))))
    (unless (or (eq dims '*)
                (equal dims (array-type-dimensions stype)))
      (cond ((cdr dims)
             (values `(,@(if (and simple-array-header-p
                                  (vop-existsp :translate simple-array-header-of-rank-p)
                                  (eq (array-type-dimensions stype) '*))
                             `((simple-array-header-of-rank-p ,original-obj ,(length dims)))
                             `(,header-test
                               ,@(when (eq (array-type-dimensions stype) '*)
                                   (if (vop-existsp :translate %array-rank=)
                                       `((%array-rank= ,obj ,(length dims)))
                                       `((= (%array-rank ,obj) ,(length dims)))))))
                       ,@(loop for d in dims
                               for i from 0
                               unless (eq '* d)
                               collect `(= (%array-dimension ,obj ,i) ,d)))
                     t))
            ((not dims)
             (values `(,header-test
                       (= (%array-rank ,obj) 0))
                     t))
            ((not (array-type-complexp type))
             (if (csubtypep stype (specifier-type 'vector))
                 (values (unless (eq '* (car dims))
                           `((= (vector-length ,obj) ,@dims)))
                         nil)
                 (values (if (eq '* (car dims))
                             `((not ,header-test))
                             `((not ,header-test)
                               (= (vector-length ,obj) ,@dims)))
                         nil)))
            (t
             (values (unless (eq '* (car dims))
                       `((if ,header-test
                             (= (%array-dimension ,obj 0) ,@dims)
                             (= (vector-length ,obj) ,@dims))))
                     nil))))))

;;; Return forms to test that OBJ has the element-type specified by type
;;; specified by TYPE, where STYPE is the type we have checked against (which
;;; is the same but for dimensions and element type). If HEADERP is true, OBJ
;;; is guaranteed to be an array-header.
(defun test-array-element-type (obj type stype headerp)
  (declare (type array-type type stype))
  (let ((obj `(truly-the ,(type-specifier stype) ,obj))
        (eltype (array-type-specialized-element-type type)))
    (unless (or (type= eltype (array-type-specialized-element-type stype))
                (eq eltype *wild-type*))
      (let ((typecode (sb-vm:saetp-typecode (find-saetp-by-ctype eltype))))
        (with-unique-names (data)
         (if (and headerp (not (array-type-complexp stype)))
             ;; If we know OBJ is an array header, and that the array is
             ;; simple, we also know there is exactly one indirection to
             ;; follow.
             `(#-x86-64
               (eq (%other-pointer-widetag (%array-data ,obj)) ,typecode)
               #+x86-64
               (widetag= (%array-data ,obj) ,typecode))
             `((do ((,data ,(if headerp `(%array-data ,obj) obj)
                           (%array-data ,data)))
                   ((not (array-header-p ,data))
                    (eq (%other-pointer-widetag ,data) ,typecode))))))))))

;;; If we can find a type predicate that tests for the type without
;;; dimensions, then use that predicate and test for dimensions.
;;; Otherwise, just do %TYPEP.
(defun source-transform-array-typep (object type)
  ;; Intercept (SIMPLE-ARRAY * (*)) because otherwise it tests
  ;; (AND SIMPLE-ARRAY (NOT ARRAY-HEADER)) to weed out rank 0 and >1.
  ;; By design the simple arrays of of rank 1 occupy a contiguous
  ;; range of widetags, and unlike the arbitrary-widetags code for unions,
  ;; this nonstandard predicate can be generically defined for all backends.
  (let ((dims (array-type-dimensions type))
        (et (array-type-element-type type)))
    (if (and (not (array-type-complexp type))
             (eq et *wild-type*)
             (equal dims '(*)))
        `(simple-rank-1-array-*-p ,object)
        (multiple-value-bind (pred stype) (find-supertype-predicate type)
          (if (and (array-type-p stype)
                   ;; (If the element type hasn't been defined yet, it's
                   ;; not safe to assume here that it will eventually
                   ;; have (UPGRADED-ARRAY-ELEMENT-TYPE type)=T, so punt.)
                   (not (unknown-type-p (array-type-element-type type)))
                   (or (eq (array-type-complexp stype) (array-type-complexp type))
                       (and (eql (array-type-complexp stype) :maybe)
                            (eql (array-type-complexp type) t))))
              (let ((complex-tag (and
                                  (eql (array-type-complexp type) t)
                                  (singleton-p dims)
                                  (and (neq et *wild-type*)
                                       (sb-vm:saetp-complex-typecode
                                        (find-saetp-by-ctype (array-type-element-type type))))))
                    (simple-array-header-p
                      (and (null (array-type-complexp stype))
                           (listp dims)
                           (cdr dims))))
                (if complex-tag
                    `(and (%other-pointer-p ,object)
                          (eq (%other-pointer-widetag ,object) ,complex-tag)
                          ,@(unless (eq (car dims) '*)
                              `((= (%array-dimension ,object 0) ,(car dims)))))
                    (multiple-value-bind (tests headerp)
                        (test-array-dimensions object type stype
                                               simple-array-header-p)
                      `(and ,@(unless (or (and headerp (eql pred 'arrayp))
                                          simple-array-header-p)
                                ;; ARRAY-HEADER-P from TESTS will test for that
                                `((,pred ,object)))
                            ,@(when (and (eql (array-type-complexp stype) :maybe)
                                         (eql (array-type-complexp type) t))
                                ;; KLUDGE: this is a bit lame; if we get here,
                                ;; we already know that OBJECT is an array, but
                                ;; (NOT SIMPLE-ARRAY) doesn't know that.  On the
                                ;; other hand, this should get compiled down to
                                ;; two widetag tests, so it's only a bit lame.
                                `((typep ,object '(not simple-array))))
                            ,@tests
                            ,@(test-array-element-type object type stype headerp)))))
              `(%typep ,object ',(type-specifier type)))))))

;;; Transform a type test against some instance type. The type test is
;;; flushed if the result is known at compile time. If not properly
;;; named, error. If sealed and has no subclasses, just test for
;;; layout-EQ. If a structure then test for layout-EQ and then a
;;; general test based on layout-inherits. Otherwise, look up the indirect
;;; class-cell and call CLASS-CELL-TYPEP at runtime.
(deftransform %instance-typep ((object spec) * * :node node)
  (aver (constant-lvar-p spec))
  (let* ((spec (lvar-value spec))
         (class (specifier-type spec))
         (name (classoid-name class))
         (otype (lvar-type object)))
    (cond
      ;; Flush tests whose result is known at compile time.
      ((not (types-equal-or-intersect otype class))
       nil)
      ((csubtypep otype class)
       t)
      ;; If not properly named, error.
      ((not (and name (eq (find-classoid name) class)))
       (compiler-error "can't compile TYPEP of anonymous or undefined ~
                        class:~%  ~S"
                       class))
      (t
       ;; Delay the type transform to give type propagation a chance.
       (delay-ir1-transform node :constraint)
       (transform-instance-typep class)))))

;;; Notice that there are some instance types for which it is almost impossible
;;; to create. One such is SEQUENCE, viz: (make-instance 'sequence) =>
;;;   "Cannot allocate an instance of #<BUILT-IN-CLASS SEQUENCE>."
;;; We should not need to check for that, just the 'inherits' vector.
;;; However, bootstrap code does a sleazy thing, making an instance of
;;; the abstract base type which is impossible for user code to do.
;;;
;;; Preferably the prototype instance for SEQUENCE would be one that could
;;; exist, so it would be a STANDARD-OBJECT and SEQUENCE. But it's not.
;;; Hence we would have to check for a layout that no code using the documented
;;; sequence API would ever see, just to get the boundary case right.
;;; The for STREAM and FILE-STREAM.
;;; But there was precedent for builtin class prototype instances
;;; failing their type predicate, i.e. (TYPEP (CLASS-PROTOTYPE X) X) => NIL
;;; which was fixed in git rev d60a6d30.
;;; Also for what it's worth, some builtins use a prototype object that is strictly
;;; deeper than layout of the named class because it is indeed the case that no
;;; object's layout can ever be EQ to that of the ancestor.
;;; e.g. a fixnum as representative of class REAL.
;;; So in actual practice, you can't make something that is a pure STREAM, etc.
#-(or x86 x86-64) ; vop-translated for these 2
(defmacro layout-depthoid-ge (layout depthoid)
  `(>= (wrapper-depthoid ,layout) ,depthoid))
(symbol-macrolet ((get-hash #+metaspace 'layout-clos-hash #-metaspace 'wrapper-clos-hash)
                  (get-flags #+metaspace 'layout-flags #-metaspace 'wrapper-flags))
(defun transform-instance-typep (classoid)
  (binding*
      ((name (classoid-name classoid))
       (wrapper (let ((res (info :type :compiler-layout name)))
                 (when (and res (not (wrapper-invalid res))) res)))
       (layout (and wrapper (wrapper-friend wrapper)))
       ((lowtag lowtag-test slot-reader)
        (cond ((csubtypep classoid (specifier-type 'funcallable-instance))
               (values sb-vm:fun-pointer-lowtag
                       '(function-with-layout-p object) '(%fun-layout object)))
              ((csubtypep classoid (specifier-type 'instance))
               (values sb-vm:instance-pointer-lowtag
                       '(%instancep object) '(%instance-layout object)))))
       (depthoid (if wrapper (wrapper-depthoid wrapper) -1))
       (type (make-symbol "TYPE")))
    (declare (ignorable layout))

    ;; Easiest case first: single bit test.
    (cond ((member name '(condition pathname structure-object))
           `(and (%instancep object)
                 (logtest (,get-flags (%instance-layout object))
                          ,(case name
                             (condition +condition-layout-flag+)
                             (pathname  +pathname-layout-flag+)
                             (t         +structure-layout-flag+)))))

          ;; TODO: remove after April 2021 release.
          ((eq name 'sb-kernel::random-class)
           (style-warn "~S should not appear in a TYPEP test" name)
           nil)

          ;; Next easiest: Sealed and no subtypes. Typically for DEFSTRUCT only.
          ;; Even if you don't seal a DEFCLASS, we're allowed to assume that things
          ;; won't change, as per CLHS 3.2.2.3 on Semantic Constraints:
          ;;  "Classes defined by defclass in the compilation environment must be defined
          ;;  at run time to have the same superclasses and same metaclass."
          ;; I think that means we should know the lowtag always. Nonetheless, this isn't
          ;; an important scenario, and only if you _do_ seal a class could this case be
          ;; reached; users rarely seal their classes since the standard doesn't say how.
          ((and wrapper
                (eq (classoid-state classoid) :sealed)
                (not (classoid-subclasses classoid)))
           (if lowtag-test
               `(and ,lowtag-test
                     ,(if (vop-existsp :translate layout-eq)
                          `(layout-eq object ,wrapper ,lowtag)
                          `(eq ,slot-reader ,layout)))
               ;; `(eq ,layout
               ;;      (if-vop-existsp (:translate %instanceoid-layout)
               ;;        (%instanceoid-layout object)
               ;;        ;; Slightly quicker than LAYOUT-OF. See also %PCL-INSTANCE-P
               ;;        (cond ((%instancep object) (%instance-layout object))
               ;;              ((funcallable-instance-p object) (%fun-layout object))
               ;;              (t ,(find-layout 't)))))
               (bug "Unexpected metatype for ~S" wrapper)))

          ;; All other structure types
          ((and (typep classoid 'structure-classoid) wrapper)
            ;; structure type tests; hierarchical layout depths
            (aver (eql lowtag sb-vm:instance-pointer-lowtag))
            ;; we used to check for invalid layouts here, but in fact that's both unnecessary and
            ;; wrong; it's unnecessary because structure classes can't be redefined, and it's wrong
            ;; because it is quite legitimate to pass an object with an invalid layout
            ;; to a structure type test.
            `(and (%instancep object)
                    ;; If we allowed structure classes to be mixed in to standard-object,
                    ;; this might have to change to consider object invalidation. Probably would
                    ;; want to track structure classoids that would render this code inadmissible.
                  ,(if (<= depthoid sb-kernel::layout-id-vector-fixed-capacity)
                       `(%structure-is-a (%instance-layout object) ,wrapper)
                       `(let ((,type (%instance-layout object)))
                          (and (layout-depthoid-ge ,type ,depthoid)
                               (%structure-is-a ,type ,wrapper))))))

          ((> depthoid 0)
           ;; fixed-depth ancestors of non-structure types:
           ;; STREAM, FILE-STREAM, STRING-STREAM, and SEQUENCE.
            #+sb-xc-host (when (typep classoid 'static-classoid)
                           ;; should have use :SEALED code above
                           (bug "Non-frozen static classoids ~S" name))
            (let ((guts `((when (zerop (,get-hash ,type))
                            (setq ,type (update-object-layout object)))
                          ,(ecase name
                            (stream
                             `(logtest (,get-flags ,type) ,+stream-layout-flag+))
                            (file-stream
                             `(logtest (,get-flags ,type) ,+file-stream-layout-flag+))
                            (string-stream
                             `(logtest (,get-flags ,type) ,+string-stream-layout-flag+))
                            ;; Testing the type EXTENDED-SEQUENCE tests for #<LAYOUT of SEQUENCE>.
                            ;; It can only arise from a direct invocation of TRANSFORM-INSTANCE-TYPEP,
                            ;; because the lisp type is not a classoid. It's done this way to define
                            ;; the logic once only, instead of both here and src/code/pred.lisp.
                            (sequence
                             `(logtest (,get-flags ,type) ,+sequence-layout-flag+))))))
              (if lowtag-test
                  `(and ,lowtag-test (let ((,type ,slot-reader)) ,@guts))
                  (if-vop-existsp (:translate %instanceoid-layout)
                    `(let ((,type (%instanceoid-layout object))) ,@guts)
                    `(block typep
                       (let ((,type (cond ((%instancep object) (%instance-layout object))
                                          ((funcallable-instance-p object) (%fun-layout object))
                                          (t (return-from typep nil)))))
                         ,@guts))))))

          (t
            `(classoid-cell-typep ',(find-classoid-cell name :create t)
                                  object))))))

;;; If the specifier argument is a quoted constant, then we consider
;;; converting into a simple predicate or other stuff. If the type is
;;; constant, but we can't transform the call, then we convert to
;;; %TYPEP. We only pass when the type is non-constant. This allows us
;;; to recognize between calls that might later be transformed
;;; successfully when a constant type is discovered. We don't give an
;;; efficiency note when we pass, since the IR1 transform will give
;;; one if necessary and appropriate.
;;;
;;; If the type is TYPE= to a type that has a predicate, then expand
;;; to that predicate. Otherwise, we dispatch off of the type's type.
;;; These transformations can increase space, but it is hard to tell
;;; when, so we ignore policy and always do them.
(defun %source-transform-typep (object type)
  (let ((ctype (careful-specifier-type type)))
    (if ctype
        (or
         ;; It's purely a waste of compiler resources to wait for IR1 to
         ;; see these 2 edge cases that can be decided right now.
         (cond ((eq ctype *universal-type*) t)
               ((eq ctype *empty-type*) nil))
         (and (not (intersection-type-p ctype))
              (multiple-value-bind (constantp value) (type-singleton-p ctype)
                (and constantp
                     `(eql ,object ',value))))
         (handler-case
             (or
              (let ((pred (backend-type-predicate ctype)))
                (when pred `(,pred ,object)))
              (let ((pred (backend-type-predicate (type-negation ctype))))
                (when pred `(not (,pred ,object)))))
           #+sb-xc-host
           (sb-kernel::cross-type-warning
             nil))
         (typecase ctype
           (hairy-type
            (source-transform-hairy-typep object ctype))
           (negation-type
            (source-transform-negation-typep object ctype))
           (union-type
            (source-transform-union-typep object ctype))
           (intersection-type
            (source-transform-intersection-typep object ctype))
           (member-type
            `(if (member ,object ',(member-type-members ctype)) t))
           (args-type
            (compiler-warn "illegal type specifier for TYPEP: ~S" type)
            (return-from %source-transform-typep (values nil t)))
           (numeric-type
            (source-transform-numeric-typep object ctype))
           (classoid
            `(%instance-typep ,object ',type))
           (array-type
            (source-transform-array-typep object ctype))
           (cons-type
            (source-transform-cons-typep object ctype))
           (character-set-type
            (source-transform-character-set-typep object ctype))
           #+sb-simd-pack
           (simd-pack-type
            (source-transform-simd-pack-typep object ctype))
           #+sb-simd-pack-256
           (simd-pack-256-type
            (source-transform-simd-pack-256-typep object ctype))
           (t nil))
         `(%typep ,object ',type))
        (values nil t))))

(defun source-transform-typep (object type)
  (when (typep type 'type-specifier)
    (check-deprecated-type type))
  (let ((name (sb-xc:gensym "OBJECT")))
    (multiple-value-bind (transform error)
        (%source-transform-typep name type)
      (if error
          (values nil t)
          (values `(let ((,name ,object))
                     (%typep-wrapper ,transform ,name ',type)))))))

;;; These things will be removed by the tree shaker, so no #+ needed.
(defvar *interesting-types* nil)
(defun involves-alien-p (ctype)
  (sb-kernel::map-type
   (lambda (type)
     (when (alien-type-type-p type) (return-from involves-alien-p t)))
   ctype))
(defun dump/restore-interesting-types (op)
  (declare (ignorable op))
  #+collect-typep-regression-dataset
  (ecase op
   (write
    (when *interesting-types*
      (let ((list (sort (loop for k being each hash-key of *interesting-types* collect k)
                        #'string< :key #'write-to-string)))
        (with-open-file (f "interesting-types.lisp-expr" :direction :output
                         :if-exists :supersede  :if-does-not-exist :create)
          (let ((*package* #+sb-xc-host (find-package "XC-STRICT-CL")
                           #-sb-xc-host #.(find-package "SB-KERNEL"))
                (*print-pretty* nil)
                (*print-length* nil)
                (*print-level* nil)
                (*print-readably* t))
            (dolist (item list)
              (write (uncross item) :stream f)
              (terpri f)))))))
   (read
    (unless (hash-table-p *interesting-types*)
      (setq *interesting-types* (make-hash-table :test 'equal :synchronized t)))
    (with-open-file (f "interesting-types.lisp-expr" :if-does-not-exist nil)
      (when f
        (let ((*package* (find-package "SB-KERNEL")))
          (loop (let ((expr (read f nil f)))
                  (when (eq expr f) (return))
                  (format t "Read ~a~%" expr)
                  (setf (gethash expr *interesting-types*) t))))))
    *interesting-types*)))

(define-source-transform typep (object spec &optional env)
  ;; KLUDGE: It looks bad to only do this on explicitly quoted forms,
  ;; since that would overlook other kinds of constants. But it turns
  ;; out that the DEFTRANSFORM for TYPEP detects any constant
  ;; lvar, transforms it into a quoted form, and gives this
  ;; source transform another chance, so it all works out OK, in a
  ;; weird roundabout way. -- WHN 2001-03-18
  (if (and (not env)
           (typep spec '(cons (eql quote) (cons t null))))
      (with-current-source-form (spec)
        ;; Decline to do the source transform when seeing an unknown
        ;; type immediately while block converting, since it may be
        ;; defined later. By waiting for the deftransform to fire
        ;; during block compilation, we give ourselves a better chance
        ;; at open-coding the type test.
        (let ((type (cadr spec)))
          ;;
          #+collect-typep-regression-dataset
          (let ((parse (specifier-type type)))
            ;; alien types aren't externalizable as trees of symbols,
            ;; and some classoid types aren't defined at the start of warm build,
            ;; making it impossible to re-parse a dump produced late in the build.
            ;; Luckily there are no cases involving compund types and classoids.
            (unless (or (involves-alien-p parse)
                        (or (classoid-p parse)
                            (and (cons-type-p parse)
                                 (classoid-p (cons-type-car-type parse)))))
              (let ((table *interesting-types*))
                (unless (hash-table-p table)
                  (setq table (dump/restore-interesting-types 'read)))
                (setf (gethash type table) t))))
          ;;
          (if (and (block-compile *compilation*)
                   (contains-unknown-type-p (careful-specifier-type type)))
              (values nil t)
              (source-transform-typep object type))))
      (values nil t)))

;;;; coercion

;;; Constant-folding.
;;;
#-sb-xc-host
(defoptimizer (coerce optimizer) ((x type) node)
  (when (and (constant-lvar-p x) (constant-lvar-p type))
    (let ((value (lvar-value x)))
      (when (or (numberp value) (characterp value))
        (constant-fold-call node)
        t))))

;;; Drops dimension information from vector types.
;;; Returns four values
;;; * vector ctype
;;; * upgraded-element ctype or requsted element
;;; * T if the upgraded-element is upgraded, i.e. it
;;;   does not contain any unknown types.
;;; * T if there were any dimensions
(defun simplify-vector-type (type)
  (labels ((process-compound-type (types)
             (let (array-types
                   element-types
                   (upgraded t)
                   dimensions-removed)
               (dolist (type types)
                 (unless (or (hairy-type-p type)
                             (sb-kernel::negation-type-p type))
                   (multiple-value-bind (type et upgraded dimensions) (simplify type)
                     (push type array-types)
                     (push et element-types)
                     (when dimensions
                       (setf dimensions-removed t))
                     (unless upgraded
                       (setf upgraded nil)))))
               (values (apply #'type-union array-types)
                       (if (member *wild-type* element-types)
                           *wild-type*
                           (apply #'type-union element-types))
                       upgraded
                       dimensions-removed)))
           (simplify (type)
             (cond ((and (array-type-p type)
                         (singleton-p (array-type-dimensions type)))
                    (let* ((upgraded t)
                           (et (array-type-specialized-element-type type))
                           (et (cond ((neq et *wild-type*)
                                      et)
                                     ((eq (array-type-element-type type) *wild-type*)
                                      et)
                                     (t
                                      (setf upgraded nil)
                                      (array-type-element-type type)))))
                      (values (specifier-type
                               (list (if (array-type-complexp type)
                                         'array
                                         'simple-array)
                                     (type-specifier et)
                                     '(*)))
                              et
                              upgraded
                              (not (eq (car (array-type-dimensions type)) '*)))))
                   ((union-type-p type)
                    (process-compound-type (union-type-types type)))
                   ((intersection-type-p type)
                    (process-compound-type (intersection-type-types type)))
                   ((member-type-p type)
                    (process-compound-type
                     (mapcar #'ctype-of (member-type-members type))))
                   (t
                    (error "~a is not a subtype of VECTOR." type)))))
    (simplify type)))


(defun check-coerce (value-type to-type type-specifier node)
  (flet ((fail ()
           (compiler-warn "Cannot coerce ~s to ~s"
                          (type-specifier value-type)
                          (type-specifier to-type))
           (setf (combination-kind node) :error)
           (give-up-ir1-transform)))
    (cond ((eq to-type *empty-type*)
           (fail))
          ((types-equal-or-intersect value-type to-type))
          ((csubtypep to-type (specifier-type 'sequence))
           (unless (csubtypep to-type (specifier-type 'sequence))
             (fail)))
          ((eql type-specifier 'character)
           (unless (types-equal-or-intersect value-type
                                             (specifier-type 'string))
             (fail)))
          ((csubtypep to-type (specifier-type 'complex))
           (unless (types-equal-or-intersect value-type
                                             (specifier-type 'number))
             (fail)))

          ((csubtypep to-type (specifier-type 'float))
           (unless (types-equal-or-intersect value-type
                                             (specifier-type 'real))
             (fail)))
          ((eq type-specifier 'function)
           (unless (types-equal-or-intersect value-type
                                             (specifier-type '(or symbol cons)))
             (fail)))
          (t
           (fail)))))

(deftransform coerce ((x type) * * :node node)
  (unless (constant-lvar-p type)
    (give-up-ir1-transform))
  (let* ((tval (lvar-value type))
         (tspec (ir1-transform-specifier-type tval))
         (value-type (lvar-type x)))
    (check-coerce value-type tspec tval node)
    ;; Note: The THE forms we use to wrap the results make sure that
    ;; specifiers like (SINGLE-FLOAT 0.0 1.0) can raise a TYPE-ERROR.
    (cond
      ((csubtypep value-type tspec)
       'x)
      ((csubtypep tspec (specifier-type 'double-float))
       `(the ,tval (%double-float x)))
      ((csubtypep tspec (specifier-type 'single-float))
       `(the ,tval (%single-float x)))
      ;; FIXME: #+long-float (t ,(error "LONG-FLOAT case needed"))
      ((csubtypep tspec (specifier-type 'float))
       (if (types-equal-or-intersect value-type (specifier-type 'float))
           `(the ,tval (if (floatp x)
                           x
                           (let ((r (the* (real :silent-conflict t) x)))
                             (declare (muffle-conditions code-deletion-note))
                             (sb-kernel:%single-float r))))
           `(the ,tval (%single-float x))))
      ((csubtypep tspec (specifier-type 'complex))
       (multiple-value-bind (part-type result-type)
           (cond ((and (numeric-type-p tspec)
                       (numeric-type-format tspec))) ; specific FLOAT type
                 ((csubtypep tspec (specifier-type '(complex float)))
                  ;; unspecific FLOAT type
                  'float)
                 ((csubtypep tspec (specifier-type '(complex rational)))
                  (values 'rational `(or ,tval rational)))
                 (t
                  (values t `(or ,tval rational))))
         (let ((result-type (or result-type tval)))
           `(cond
              ((not (typep x 'complex))
               (the ,result-type (complex (coerce x ',part-type))))
              ((typep x ',tval)
               x)
              (t         ; X is COMPLEX, but not of the requested type
               ,(if (eq part-type 'rational)
                    ;; Can't coerce non-rational to a rational and
                    ;; CHECK-COERCE will warn, so just full call
                    ;; COERCE and let it signal an error.
                    `(locally (declare (notinline coerce))
                       (coerce x ',tval))
                    `(the ,result-type
                          (complex (coerce (realpart x) ',part-type)
                                   (coerce (imagpart x) ',part-type)))))))))
      ((eq tval 'character)
       `(character x))
      ;; Handle specialized element types for 1D arrays.
      ((multiple-value-bind (result already-type-p dimension specialization)
           (cond ((or (and (array-type-p tspec)
                           (neq (array-type-complexp tspec) t) ; :MAYBE and NIL are good
                           (not (contains-unknown-type-p (array-type-element-type tspec)))
                           ;; just for requesting (array nil (*)), you lose
                           (neq (array-type-specialized-element-type tspec) *empty-type*)
                           (consp (array-type-dimensions tspec))))
                  (values tspec
                          (source-transform-array-typep 'x tspec)
                          (car (array-type-dimensions tspec))
                          (let ((et (array-type-specialized-element-type tspec)))
                            (unless (or (eq et *universal-type*) ; don't need
                                        ;; * is illegal as :element-type; in this context
                                        ;; it means to produce a SIMPLE-VECTOR
                                        (eq et *wild-type*))
                              `(:element-type ',(type-specifier et))))))
                 ;; Check for string types.  This loses on (STRING 1) and such.
                 #+sb-unicode
                 ((type= tspec (specifier-type 'simple-string))
                  (values 'simple-string '(simple-string-p x) '* '(:element-type 'character)))
                 #+sb-unicode
                 ((type= tspec (specifier-type 'string))
                  (values 'string '(stringp x) '* '(:element-type 'character))))
         (when result
           ;; If the dimension is in the type, we check the input length if safety > 0,
           ;; though technically CLHS would allow not checking in safety < 3.
           ;; And if mismatch occurs in unsafe code, the results accords with the
           ;; specifier, NOT the dimension of the input. This is a rational choice
           ;; because one could not argue that incorrect code should have taken the
           ;; bad input's length when COERCE was asked for an exact type of output.
           `(truly-the ,result
               (if ,already-type-p
                   x
                   ,(cond ((eq dimension '*)
                           #+ubsan
                           ;; Passing :INITIAL-CONTENTS avoids allocating ubsan shadow bits,
                           ;; but redundantly checks the length of the input in MAKE-ARRAY's
                           ;; transform because we don't or can't infer that LENGTH gives the
                           ;; same answer each time it is called on X. There may be a way to
                           ;; extract more efficiency - at least eliminate the unreachable
                           ;; error-signaling code on mismatch - but I don't care to try.
                           `(make-array (length x) ,@specialization :initial-contents x)
                           #-ubsan ; better: do not generate a redundant LENGTH check
                           `(replace (make-array (length x) ,@specialization) x))
                          ((policy node (= safety 0)) ; Disregard the input length
                           `(replace (make-array ,dimension ,@specialization) x))
                          (t
                           `(make-array ,dimension ,@specialization :initial-contents x))))))))
      ((type= tspec (specifier-type 'list))
       `(coerce-to-list x))
      ((csubtypep tspec (specifier-type 'function))
       (if (csubtypep (lvar-type x) (specifier-type 'symbol))
           `(coerce-symbol-to-fun x)
           ;; if X can later be derived as FUNCTION then we don't want
           ;; to call COERCE-TO-FUN, because there's no smartness
           ;; that can undo that and see that it's really (IDENTITY X).
           (progn (delay-ir1-transform node :constraint)
                  `(coerce-to-fun x))))
      (t
       (give-up-ir1-transform
        "~@<open coding coercion to ~S not implemented.~:@>"
        tval)))))

(deftransform #+64-bit unsigned-byte-64-p #-64-bit unsigned-byte-32-p
  ((value) (fixnum) * :important nil)
  `(>= value 0))

(deftransform %other-pointer-p ((object))
  (let ((this-type
          (specifier-type '(or fixnum
                            #+64-bit single-float
                            function
                            list
                            instance
                            character))))
    (cond ((not (types-equal-or-intersect this-type (lvar-type object))))
          ((csubtypep (lvar-type object) this-type)
           nil)
          ((give-up-ir1-transform)))))

;;; BIGNUMP is simpler than INTEGERP, so if we can rule out FIXNUM then ...
(deftransform integerp ((x) ((not fixnum)) * :important nil) '(bignump x))
