(or end length)
(sequence-bounding-indices-bad-error vector start end)))))
-(defun specialized-list-seek-function-name (function-name key-functions variant)
+(deftype eq-comparable-type ()
+ '(or fixnum (not number)))
+
+;;; True if EQL comparisons involving type can be simplified to EQ.
+(defun eq-comparable-type-p (type)
+ (csubtypep type (specifier-type 'eq-comparable-type)))
+
+(defun specialized-list-seek-function-name (function-name key-functions &optional variant)
(or (find-symbol (with-output-to-string (s)
;; Write "%NAME-FUN1-FUN2-FUN3", etc. Not only is
;; this ever so slightly faster then FORMAT, this
function-name key-functions variant)))
(defun transform-list-item-seek (name item list key test test-not node)
+ (when (and test test-not)
+ (abort-ir1-transform "Both ~S and ~S supplied to ~S." :test :test-not name))
;; If TEST is EQL, drop it.
- (when (and test (lvar-for-named-function test 'eql))
+ (when (and test (lvar-fun-is test '(eql)))
(setf test nil))
;; Ditto for KEY IDENTITY.
- (when (and key (lvar-for-named-function key 'identity))
+ (when (and key (lvar-fun-is key '(identity)))
(setf key nil))
;; Key can legally be NIL, but if it's NIL for sure we pretend it's
;; not there at all. If it might be NIL, make up a form to that
(%coerce-callable-to-fun key)
#'identity)))
(t
- (values key '(%coerce-callable-to-fun key))))))
- (let* ((c-test (cond ((and test (lvar-for-named-function test 'eq))
+ (values key (ensure-lvar-fun-form key 'key))))))
+ (let* ((c-test (cond ((and test (lvar-fun-is test '(eq)))
(setf test nil)
'eq)
((and (not test) (not test-not))
(when (eq-comparable-type-p (lvar-type item))
'eq))))
- (funs (remove nil (list (and key 'key) (cond (test 'test)
- (test-not 'test-not)))))
+ (funs (delete nil (list (when key (list key 'key))
+ (when test (list test 'test))
+ (when test-not (list test-not 'test-not)))))
(target-expr (if key '(%funcall key target) 'target))
(test-expr (cond (test `(%funcall test item ,target-expr))
(test-not `(not (%funcall test-not item ,target-expr)))
(when tail
`(if (let ((this ',(car tail)))
,(ecase name
- (assoc
- `(and this (let ((target (car this)))
- ,test-expr)))
+ ((assoc rassoc)
+ (let ((cxx (if (eq name 'assoc) 'car 'cdr)))
+ `(and this (let ((target (,cxx this)))
+ ,test-expr))))
(member
`(let ((target this))
,test-expr))))
',(ecase name
- (assoc (car tail))
+ ((assoc rassoc) (car tail))
(member tail))
,(open-code (cdr tail)))))
- (ensure-fun (fun)
- (if (eq 'key fun)
+ (ensure-fun (args)
+ (if (eq 'key (second args))
key-form
- `(%coerce-callable-to-fun ,fun))))
+ (apply #'ensure-lvar-fun-form args))))
+ (let* ((cp (constant-lvar-p list))
+ (c-list (when cp (lvar-value list))))
+ (cond ((and cp c-list (member name '(assoc rassoc member))
+ (policy node (>= speed space)))
+ `(let ,(mapcar (lambda (fun) `(,(second fun) ,(ensure-fun fun))) funs)
+ ,(open-code c-list)))
+ ((and cp (not c-list))
+ ;; constant nil list
+ (if (eq name 'adjoin)
+ '(list item)
+ nil))
+ (t
+ ;; specialized out-of-line version
+ `(,(specialized-list-seek-function-name name (mapcar #'second funs) c-test)
+ item list ,@(mapcar #'ensure-fun funs)))))))))
+
+(defun transform-list-pred-seek (name pred list key node)
+ ;; If KEY is IDENTITY, drop it.
+ (when (and key (lvar-fun-is key '(identity)))
+ (setf key nil))
+ ;; Key can legally be NIL, but if it's NIL for sure we pretend it's
+ ;; not there at all. If it might be NIL, make up a form to that
+ ;; ensures it is a function.
+ (multiple-value-bind (key key-form)
+ (when key
+ (let ((key-type (lvar-type key))
+ (null-type (specifier-type 'null)))
+ (cond ((csubtypep key-type null-type)
+ (values nil nil))
+ ((csubtypep null-type key-type)
+ (values key '(if key
+ (%coerce-callable-to-fun key)
+ #'identity)))
+ (t
+ (values key (ensure-lvar-fun-form key 'key))))))
+ (let ((test-expr `(%funcall pred ,(if key '(%funcall key target) 'target)))
+ (pred-expr (ensure-lvar-fun-form pred 'pred)))
+ (when (member name '(member-if-not assoc-if-not rassoc-if-not))
+ (setf test-expr `(not ,test-expr)))
+ (labels ((open-code (tail)
+ (when tail
+ `(if (let ((this ',(car tail)))
+ ,(ecase name
+ ((assoc-if assoc-if-not rassoc-if rassoc-if-not)
+ (let ((cxx (if (member name '(assoc-if assoc-if-not)) 'car 'cdr)))
+ `(and this (let ((target (,cxx this)))
+ ,test-expr))))
+ ((member-if member-if-not)
+ `(let ((target this))
+ ,test-expr))))
+ ',(ecase name
+ ((assoc-if assoc-if-not rassoc-if rassoc-if-not)
+ (car tail))
+ ((member-if member-if-not)
+ tail))
+ ,(open-code (cdr tail))))))
(let* ((cp (constant-lvar-p list))
(c-list (when cp (lvar-value list))))
(cond ((and cp c-list (policy node (>= speed space)))
- `(let ,(mapcar (lambda (fun) `(,fun ,(ensure-fun fun))) funs)
+ `(let ((pred ,pred-expr)
+ ,@(when key `((key ,key-form))))
,(open-code c-list)))
((and cp (not c-list))
;; constant nil list -- nothing to find!
nil)
(t
;; specialized out-of-line version
- `(,(specialized-list-seek-function-name name funs c-test)
- item list ,@(mapcar #'ensure-fun funs)))))))))
-
-(deftransform member ((item list &key key test test-not) * * :node node)
- (transform-list-item-seek 'member item list key test test-not node))
-
-(deftransform assoc ((item list &key key test test-not) * * :node node)
- (transform-list-item-seek 'assoc item list key test test-not node))
+ `(,(specialized-list-seek-function-name name (when key '(key)))
+ ,pred-expr list ,@(when key (list key-form))))))))))
+
+(macrolet ((def (name &optional if/if-not)
+ (let ((basic (symbolicate "%" name))
+ (basic-eq (symbolicate "%" name "-EQ"))
+ (basic-key (symbolicate "%" name "-KEY"))
+ (basic-key-eq (symbolicate "%" name "-KEY-EQ")))
+ `(progn
+ (deftransform ,name ((item list &key key test test-not) * * :node node)
+ (transform-list-item-seek ',name item list key test test-not node))
+ (deftransform ,basic ((item list) (eq-comparable-type t))
+ `(,',basic-eq item list))
+ (deftransform ,basic-key ((item list) (eq-comparable-type t))
+ `(,',basic-key-eq item list))
+ ,@(when if/if-not
+ (let ((if-name (symbolicate name "-IF"))
+ (if-not-name (symbolicate name "-IF-NOT")))
+ `((deftransform ,if-name ((pred list &key key) * * :node node)
+ (transform-list-pred-seek ',if-name pred list key node))
+ (deftransform ,if-not-name ((pred list &key key) * * :node node)
+ (transform-list-pred-seek ',if-not-name pred list key node)))))))))
+ (def adjoin)
+ (def assoc t)
+ (def member t)
+ (def rassoc t))
(deftransform memq ((item list) (t (constant-arg list)))
(labels ((rec (tail)
(vector t &key (:start t) (:end t))
*
:node node)
- (let ((type (lvar-type seq))
- (element-type (type-specifier (extract-upgraded-element-type seq))))
- (cond ((and (neq '* element-type) (policy node (> speed space)))
+ (let* ((element-ctype (extract-upgraded-element-type seq))
+ (element-type (type-specifier element-ctype))
+ (type (lvar-type seq))
+ (saetp (unless (eq *wild-type* element-ctype)
+ (find-saetp-by-ctype element-ctype))))
+ (cond ((eq *wild-type* element-ctype)
+ (delay-ir1-transform node :constraint)
+ `(vector-fill* seq item start end))
+ ((and saetp (sb!vm::valid-bit-bash-saetp-p saetp))
+ (let* ((n-bits (sb!vm:saetp-n-bits saetp))
+ (basher-name (format nil "UB~D-BASH-FILL" n-bits))
+ (basher (or (find-symbol basher-name
+ (load-time-value (find-package :sb!kernel)))
+ (abort-ir1-transform
+ "Unknown fill basher, please report to sbcl-devel: ~A"
+ basher-name)))
+ (kind (cond ((sb!vm:saetp-fixnum-p saetp) :tagged)
+ ((member element-type '(character base-char)) :char)
+ ((eq element-type 'single-float) :single-float)
+ #!+#.(cl:if (cl:= 64 sb!vm:n-word-bits) '(and) '(or))
+ ((eq element-type 'double-float) :double-float)
+ #!+#.(cl:if (cl:= 64 sb!vm:n-word-bits) '(and) '(or))
+ ((equal element-type '(complex single-float))
+ :complex-single-float)
+ (t
+ (aver (integer-type-p element-ctype))
+ :bits)))
+ ;; BASH-VALUE is a word that we can repeatedly smash
+ ;; on the array: for less-than-word sized elements it
+ ;; contains multiple copies of the fill item.
+ (bash-value
+ (if (constant-lvar-p item)
+ (let ((tmp (lvar-value item)))
+ (unless (ctypep tmp element-ctype)
+ (abort-ir1-transform "~S is not ~S" tmp element-type))
+ (let* ((bits
+ (ldb (byte n-bits 0)
+ (ecase kind
+ (:tagged
+ (ash tmp sb!vm:n-fixnum-tag-bits))
+ (:char
+ (char-code tmp))
+ (:bits
+ tmp)
+ (:single-float
+ (single-float-bits tmp))
+ #!+#.(cl:if (cl:= 64 sb!vm:n-word-bits) '(and) '(or))
+ (:double-float
+ (logior (ash (double-float-high-bits tmp) 32)
+ (double-float-low-bits tmp)))
+ #!+#.(cl:if (cl:= 64 sb!vm:n-word-bits) '(and) '(or))
+ (:complex-single-float
+ (logior (ash (single-float-bits (imagpart tmp)) 32)
+ (ldb (byte 32 0)
+ (single-float-bits (realpart tmp))))))))
+ (res bits))
+ (loop for i of-type sb!vm:word from n-bits by n-bits
+ until (= i sb!vm:n-word-bits)
+ do (setf res (ldb (byte sb!vm:n-word-bits 0)
+ (logior res (ash bits i)))))
+ res))
+ (progn
+ (delay-ir1-transform node :constraint)
+ `(let* ((bits (ldb (byte ,n-bits 0)
+ ,(ecase kind
+ (:tagged
+ `(ash item ,sb!vm:n-fixnum-tag-bits))
+ (:char
+ `(char-code item))
+ (:bits
+ `item)
+ (:single-float
+ `(single-float-bits item))
+ #!+#.(cl:if (cl:= 64 sb!vm:n-word-bits) '(and) '(or))
+ (:double-float
+ `(logior (ash (double-float-high-bits item) 32)
+ (double-float-low-bits item)))
+ #!+#.(cl:if (cl:= 64 sb!vm:n-word-bits) '(and) '(or))
+ (:complex-single-float
+ `(logior (ash (single-float-bits (imagpart item)) 32)
+ (ldb (byte 32 0)
+ (single-float-bits (realpart item))))))))
+ (res bits))
+ (declare (type sb!vm:word res))
+ ,@(unless (= sb!vm:n-word-bits n-bits)
+ `((loop for i of-type sb!vm:word from ,n-bits by ,n-bits
+ until (= i sb!vm:n-word-bits)
+ do (setf res
+ (ldb (byte ,sb!vm:n-word-bits 0)
+ (logior res (ash bits (truly-the (integer 0 ,(- sb!vm:n-word-bits n-bits)) i))))))))
+ res)))))
+ (values
+ `(with-array-data ((data seq)
+ (start start)
+ (end end)
+ :check-fill-pointer t)
+ (declare (type (simple-array ,element-type 1) data))
+ (declare (type index start end))
+ (declare (optimize (safety 0) (speed 3))
+ (muffle-conditions compiler-note))
+ (,basher ,bash-value data start (- end start))
+ seq)
+ `((declare (type ,element-type item))))))
+ ((policy node (> speed space))
(values
`(with-array-data ((data seq)
(start start)
:start start
:end (%check-generic-sequence-bounds seq start end)))
\f
-;;;; utilities
-
-;;; Return true if LVAR's only use is a non-NOTINLINE reference to a
-;;; global function with one of the specified NAMES.
-(defun lvar-fun-is (lvar names)
- (declare (type lvar lvar) (list names))
- (let ((use (lvar-uses lvar)))
- (and (ref-p use)
- (let ((leaf (ref-leaf use)))
- (and (global-var-p leaf)
- (eq (global-var-kind leaf) :global-function)
- (not (null (member (leaf-source-name leaf) names
- :test #'equal))))))))
-
-;;; If LVAR is a constant lvar, the return the constant value. If it
-;;; is null, then return default, otherwise quietly give up the IR1
-;;; transform.
-;;;
-;;; ### Probably should take an ARG and flame using the NAME.
-(defun constant-value-or-lose (lvar &optional default)
- (declare (type (or lvar null) lvar))
- (cond ((not lvar) default)
- ((constant-lvar-p lvar)
- (lvar-value lvar))
- (t
- (give-up-ir1-transform))))
-
-
;;;; hairy sequence transforms
;;; FIXME: no hairy sequence transforms in SBCL?
(def!constant vector-data-bit-offset
(* sb!vm:vector-data-offset sb!vm:n-word-bits))
-(eval-when (:compile-toplevel)
-(defun valid-bit-bash-saetp-p (saetp)
- ;; BIT-BASHing isn't allowed on simple vectors that contain pointers
- (and (not (eq t (sb!vm:saetp-specifier saetp)))
- ;; Disallowing (VECTOR NIL) also means that we won't transform
- ;; sequence functions into bit-bashing code and we let the
- ;; generic sequence functions signal errors if necessary.
- (not (zerop (sb!vm:saetp-n-bits saetp)))
- ;; Due to limitations with the current BIT-BASHing code, we can't
- ;; BIT-BASH reliably on arrays whose element types are larger
- ;; than the word size.
- (<= (sb!vm:saetp-n-bits saetp) sb!vm:n-word-bits)))
-) ; EVAL-WHEN
-
;;; FIXME: In the copy loops below, we code the loops in a strange
;;; fashion:
;;;
;;; you tweak it, make sure that you compare the disassembly, if not the
;;; performance of, the functions implementing string streams
;;; (e.g. SB!IMPL::STRING-OUCH).
-(eval-when (:compile-toplevel :load-toplevel :execute)
+(eval-when (#-sb-xc :compile-toplevel :load-toplevel :execute)
(defun make-replace-transform (saetp sequence-type1 sequence-type2)
`(deftransform replace ((seq1 seq2 &key (start1 0) (start2 0) end1 end2)
(,sequence-type1 ,sequence-type2 &rest t)
,sequence-type1
:node node)
- ,(cond
- ((and saetp (valid-bit-bash-saetp-p saetp)) nil)
- ;; If the sequence types are different, SEQ1 and SEQ2 must
- ;; be distinct arrays, and we can open code the copy loop.
- ((not (eql sequence-type1 sequence-type2)) nil)
- ;; If we're not bit-bashing, only allow cases where we
- ;; can determine the order of copying up front. (There
- ;; are actually more cases we can handle if we know the
- ;; amount that we're copying, but this handles the
- ;; common cases.)
- (t '(unless (= (constant-value-or-lose start1 0)
- (constant-value-or-lose start2 0))
- (give-up-ir1-transform))))
`(let* ((len1 (length seq1))
(len2 (length seq2))
(end1 (or end1 len1))
(end2 (or end2 len2))
- (replace-len1 (- end1 start1))
- (replace-len2 (- end2 start2)))
+ (replace-len (min (- end1 start1) (- end2 start2))))
,(unless (policy node (= safety 0))
`(progn
- (unless (<= 0 start1 end1 len1)
- (sequence-bounding-indices-bad-error seq1 start1 end1))
- (unless (<= 0 start2 end2 len2)
- (sequence-bounding-indices-bad-error seq2 start2 end2))))
+ (unless (<= 0 start1 end1 len1)
+ (sequence-bounding-indices-bad-error seq1 start1 end1))
+ (unless (<= 0 start2 end2 len2)
+ (sequence-bounding-indices-bad-error seq2 start2 end2))))
,',(cond
- ((and saetp (valid-bit-bash-saetp-p saetp))
- (let* ((n-element-bits (sb!vm:saetp-n-bits saetp))
- (bash-function (intern (format nil "UB~D-BASH-COPY"
- n-element-bits)
- (find-package "SB!KERNEL"))))
- `(funcall (function ,bash-function) seq2 start2
- seq1 start1 (min replace-len1 replace-len2))))
- (t
- ;; We can expand the loop inline here because we
- ;; would have given up the transform (see above)
- ;; if we didn't have constant matching start
- ;; indices.
- '(do ((i start1 (1+ i))
- (j start2 (1+ j))
- (end (+ start1
- (min replace-len1 replace-len2))))
- ((>= i end))
- (declare (optimize (insert-array-bounds-checks 0)))
- (setf (aref seq1 i) (aref seq2 j)))))
+ ((and saetp (sb!vm:valid-bit-bash-saetp-p saetp))
+ (let* ((n-element-bits (sb!vm:saetp-n-bits saetp))
+ (bash-function (intern (format nil "UB~D-BASH-COPY"
+ n-element-bits)
+ (find-package "SB!KERNEL"))))
+ `(funcall (function ,bash-function) seq2 start2
+ seq1 start1 replace-len)))
+ (t
+ `(if (and
+ ;; If the sequence types are different, SEQ1 and
+ ;; SEQ2 must be distinct arrays.
+ ,(eql sequence-type1 sequence-type2)
+ (eq seq1 seq2) (> start1 start2))
+ (do ((i (truly-the index (+ start1 replace-len -1))
+ (1- i))
+ (j (truly-the index (+ start2 replace-len -1))
+ (1- j)))
+ ((< i start1))
+ (declare (optimize (insert-array-bounds-checks 0)))
+ (setf (aref seq1 i) (aref seq2 j)))
+ (do ((i start1 (1+ i))
+ (j start2 (1+ j))
+ (end (+ start1 replace-len)))
+ ((>= i end))
+ (declare (optimize (insert-array-bounds-checks 0)))
+ (setf (aref seq1 i) (aref seq2 j))))))
seq1))))
(macrolet
;;; this transform to non-strings, but I chose to just do the case that
;;; should cover 95% of CONCATENATE performance complaints for now.
;;; -- JES, 2007-11-17
+;;;
+;;; Only handle the simple result type cases. If somebody does (CONCATENATE
+;;; '(STRING 6) ...) their code won't be optimized, but nobody does that in
+;;; practice.
(deftransform concatenate ((result-type &rest lvars)
- (symbol &rest sequence)
- *
- :policy (> speed space))
- (unless (constant-lvar-p result-type)
- (give-up-ir1-transform))
- (let* ((element-type (let ((type (lvar-value result-type)))
- ;; Only handle the simple result type cases. If
- ;; somebody does (CONCATENATE '(STRING 6) ...)
- ;; their code won't be optimized, but nobody does
- ;; that in practice.
- (case type
- ((string simple-string) 'character)
- ((base-string simple-base-string) 'base-char)
- (t (give-up-ir1-transform)))))
- (vars (loop for x in lvars collect (gensym)))
- (lvar-values (loop for lvar in lvars
- collect (when (constant-lvar-p lvar)
- (lvar-value lvar))))
- (lengths
- (loop for value in lvar-values
- for var in vars
- collect (if value
- (length value)
- `(sb!impl::string-dispatch ((simple-array * (*))
- sequence)
- ,var
- (declare (muffle-conditions compiler-note))
- (length ,var))))))
- `(apply
- (lambda ,vars
- (declare (ignorable ,@vars))
- (let* ((.length. (+ ,@lengths))
- (.pos. 0)
- (.string. (make-string .length. :element-type ',element-type)))
- (declare (type index .length. .pos.)
- (muffle-conditions compiler-note))
- ,@(loop for value in lvar-values
- for var in vars
- collect (if (stringp value)
- ;; Fold the array reads for constant arguments
- `(progn
- ,@(loop for c across value
- collect `(setf (aref .string.
- .pos.) ,c)
- collect `(incf .pos.)))
- `(sb!impl::string-dispatch
- (#!+sb-unicode
- (simple-array character (*))
- (simple-array base-char (*))
- t)
- ,var
- (replace .string. ,var :start1 .pos.)
- (incf .pos. (length ,var)))))
- .string.))
- lvars)))
+ ((constant-arg
+ (member string simple-string base-string simple-base-string))
+ &rest sequence)
+ * :node node)
+ (let ((vars (loop for x in lvars collect (gensym)))
+ (type (lvar-value result-type)))
+ (if (policy node (<= speed space))
+ ;; Out-of-line
+ `(lambda (.dummy. ,@vars)
+ (declare (ignore .dummy.))
+ ,(ecase type
+ ((string simple-string)
+ `(%concatenate-to-string ,@vars))
+ ((base-string simple-base-string)
+ `(%concatenate-to-base-string ,@vars))))
+ ;; Inline
+ (let* ((element-type (ecase type
+ ((string simple-string) 'character)
+ ((base-string simple-base-string) 'base-char)))
+ (lvar-values (loop for lvar in lvars
+ collect (when (constant-lvar-p lvar)
+ (lvar-value lvar))))
+ (lengths
+ (loop for value in lvar-values
+ for var in vars
+ collect (if value
+ (length value)
+ `(sb!impl::string-dispatch ((simple-array * (*))
+ sequence)
+ ,var
+ (declare (muffle-conditions compiler-note))
+ (length ,var))))))
+ `(apply
+ (lambda ,vars
+ (declare (ignorable ,@vars))
+ (let* ((.length. (+ ,@lengths))
+ (.pos. 0)
+ (.string. (make-string .length. :element-type ',element-type)))
+ (declare (type index .length. .pos.)
+ (muffle-conditions compiler-note))
+ ,@(loop for value in lvar-values
+ for var in vars
+ collect (if (stringp value)
+ ;; Fold the array reads for constant arguments
+ `(progn
+ ,@(loop for c across value
+ collect `(setf (aref .string.
+ .pos.) ,c)
+ collect `(incf .pos.)))
+ `(sb!impl::string-dispatch
+ (#!+sb-unicode
+ (simple-array character (*))
+ (simple-array base-char (*))
+ t)
+ ,var
+ (replace .string. ,var :start1 .pos.)
+ (incf .pos. (length ,var)))))
+ .string.))
+ lvars)))))
\f
;;;; CONS accessor DERIVE-TYPE optimizers
(defoptimizer (car derive-type) ((cons))
- (let ((type (lvar-type cons))
+ ;; This and CDR needs to use LVAR-CONSERVATIVE-TYPE because type inference
+ ;; gets confused by things like (SETF CAR).
+ (let ((type (lvar-conservative-type cons))
(null-type (specifier-type 'null)))
(cond ((eq type null-type)
null-type)
(cons-type-car-type type)))))
(defoptimizer (cdr derive-type) ((cons))
- (let ((type (lvar-type cons))
+ (let ((type (lvar-conservative-type cons))
(null-type (specifier-type 'null)))
(cond ((eq type null-type)
null-type)
(sequence-bounding-indices-bad-error
sequence start end)
(values find position)))
- (let ((key-i (funcall key i)))
- (when (and end (>= index end))
- (return (values find position)))
- (when (>= index start)
+ (when (and end (>= index end))
+ (return (values find position)))
+ (when (>= index start)
+ (let ((key-i (funcall key i)))
(,',condition (funcall predicate key-i)
- ;; This hack of dealing with non-NIL
- ;; FROM-END for list data by iterating
- ;; forward through the list and keeping
- ;; track of the last time we found a match
- ;; might be more screwy than what the user
- ;; expects, but it seems to be allowed by
- ;; the ANSI standard. (And if the user is
- ;; screwy enough to ask for FROM-END
- ;; behavior on list data, turnabout is
- ;; fair play.)
- ;;
- ;; It's also not enormously efficient,
- ;; calling PREDICATE and KEY more often
- ;; than necessary; but all the
- ;; alternatives seem to have their own
- ;; efficiency problems.
- (if from-end
- (setf find i
- position index)
- (return (values i index))))))
+ ;; This hack of dealing with non-NIL
+ ;; FROM-END for list data by iterating
+ ;; forward through the list and keeping
+ ;; track of the last time we found a
+ ;; match might be more screwy than what
+ ;; the user expects, but it seems to be
+ ;; allowed by the ANSI standard. (And
+ ;; if the user is screwy enough to ask
+ ;; for FROM-END behavior on list data,
+ ;; turnabout is fair play.)
+ ;;
+ ;; It's also not enormously efficient,
+ ;; calling PREDICATE and KEY more often
+ ;; than necessary; but all the
+ ;; alternatives seem to have their own
+ ;; efficiency problems.
+ (if from-end
+ (setf find i
+ position index)
+ (return (values i index))))))
(incf index))))))
(def %find-position-if when)
(def %find-position-if-not unless))
'(%find-position-vector-macro item sequence
from-end start end key test))
+(deftransform %find-position ((item sequence from-end start end key test)
+ (character string t t t function function)
+ *
+ :policy (> speed space))
+ (if (eq '* (upgraded-element-type-specifier sequence))
+ (let ((form
+ `(sb!impl::string-dispatch ((simple-array character (*))
+ (simple-array base-char (*))
+ (simple-array nil (*)))
+ sequence
+ (%find-position item sequence from-end start end key test))))
+ (if (csubtypep (lvar-type sequence) (specifier-type 'simple-string))
+ form
+ ;; Otherwise we'd get three instances of WITH-ARRAY-DATA from
+ ;; %FIND-POSITION.
+ `(with-array-data ((sequence sequence :offset-var offset)
+ (start start)
+ (end end)
+ :check-fill-pointer t)
+ (multiple-value-bind (elt index) ,form
+ (values elt (when (fixnump index) (- index offset)))))))
+ ;; The type is known exactly, other transforms will take care of it.
+ (give-up-ir1-transform)))
+
;;; logic to unravel :TEST, :TEST-NOT, and :KEY options in FIND,
;;; POSITION-IF, etc.
(define-source-transform effective-find-position-test (test test-not)