1.0.0.22: Extensible sequences. (EXPERIMENTAL: Do Not Use As Food)
[sbcl.git] / src / compiler / seqtran.lisp
index b640f51..de9f0ff 100644 (file)
 
 (defun mapfoo-transform (fn arglists accumulate take-car)
   (collect ((do-clauses)
-           (args-to-fn)
-           (tests))
+            (args-to-fn)
+            (tests))
     (let ((n-first (gensym)))
       (dolist (a (if accumulate
-                    arglists
-                    `(,n-first ,@(rest arglists))))
-       (let ((v (gensym)))
-         (do-clauses `(,v ,a (cdr ,v)))
-         (tests `(endp ,v))
-         (args-to-fn (if take-car `(car ,v) v))))
+                     arglists
+                     `(,n-first ,@(rest arglists))))
+        (let ((v (gensym)))
+          (do-clauses `(,v ,a (cdr ,v)))
+          (tests `(endp ,v))
+          (args-to-fn (if take-car `(car ,v) v))))
 
       (let* ((fn-sym (gensym))  ; for ONCE-ONLY-ish purposes
-            (call `(funcall ,fn-sym . ,(args-to-fn)))
-            (endtest `(or ,@(tests))))
-       (ecase accumulate
-         (:nconc
-          (let ((temp (gensym))
-                (map-result (gensym)))
-            `(let ((,fn-sym ,fn)
-                   (,map-result (list nil)))
-               (do-anonymous ((,temp ,map-result) . ,(do-clauses))
-                             (,endtest (cdr ,map-result))
-                 (setq ,temp (last (nconc ,temp ,call)))))))
-         (:list
-          (let ((temp (gensym))
-                (map-result (gensym)))
-            `(let ((,fn-sym ,fn)
-                   (,map-result (list nil)))
-               (do-anonymous ((,temp ,map-result) . ,(do-clauses))
-                             (,endtest (cdr ,map-result))
-                 (rplacd ,temp (setq ,temp (list ,call)))))))
-         ((nil)
-          `(let ((,fn-sym ,fn)
-                 (,n-first ,(first arglists)))
-             (do-anonymous ,(do-clauses)
-                           (,endtest ,n-first) ,call))))))))
+             (call `(funcall ,fn-sym . ,(args-to-fn)))
+             (endtest `(or ,@(tests))))
+        (ecase accumulate
+          (:nconc
+           (let ((temp (gensym))
+                 (map-result (gensym)))
+             `(let ((,fn-sym ,fn)
+                    (,map-result (list nil)))
+                (do-anonymous ((,temp ,map-result) . ,(do-clauses))
+                              (,endtest (cdr ,map-result))
+                  (setq ,temp (last (nconc ,temp ,call)))))))
+          (:list
+           (let ((temp (gensym))
+                 (map-result (gensym)))
+             `(let ((,fn-sym ,fn)
+                    (,map-result (list nil)))
+                (do-anonymous ((,temp ,map-result) . ,(do-clauses))
+                              (,endtest (truly-the list (cdr ,map-result)))
+                  (rplacd ,temp (setq ,temp (list ,call)))))))
+          ((nil)
+           `(let ((,fn-sym ,fn)
+                  (,n-first ,(first arglists)))
+              (do-anonymous ,(do-clauses)
+                            (,endtest (truly-the list ,n-first))
+                            ,call))))))))
 
 (define-source-transform mapc (function list &rest more-lists)
   (mapfoo-transform function (cons list more-lists) nil t))
 ;;; TRULY-THE for the most specific type we can determine.
 (deftransform map ((result-type-arg fun seq &rest seqs) * * :node node)
   (let* ((seq-names (make-gensym-list (1+ (length seqs))))
-        (bare `(%map result-type-arg fun ,@seq-names))
-        (constant-result-type-arg-p (constant-continuation-p result-type-arg))
-        ;; what we know about the type of the result. (Note that the
-        ;; "result type" argument is not necessarily the type of the
-        ;; result, since NIL means the result has NULL type.)
-        (result-type (if (not constant-result-type-arg-p)
-                         'consed-sequence
-                         (let ((result-type-arg-value
-                                (continuation-value result-type-arg)))
-                           (if (null result-type-arg-value)
-                               'null
-                               result-type-arg-value)))))
+         (bare `(%map result-type-arg fun ,@seq-names))
+         (constant-result-type-arg-p (constant-lvar-p result-type-arg))
+         ;; what we know about the type of the result. (Note that the
+         ;; "result type" argument is not necessarily the type of the
+         ;; result, since NIL means the result has NULL type.)
+         (result-type (if (not constant-result-type-arg-p)
+                          'consed-sequence
+                          (let ((result-type-arg-value
+                                 (lvar-value result-type-arg)))
+                            (if (null result-type-arg-value)
+                                'null
+                                result-type-arg-value)))))
     `(lambda (result-type-arg fun ,@seq-names)
        (truly-the ,result-type
-        ,(cond ((policy node (< safety 3))
-                ;; ANSI requires the length-related type check only
-                ;; when the SAFETY quality is 3... in other cases, we
-                ;; skip it, because it could be expensive.
-                bare)
-               ((not constant-result-type-arg-p)
-                `(sequence-of-checked-length-given-type ,bare
-                                                        result-type-arg))
-               (t
-                (let ((result-ctype (ir1-transform-specifier-type
-                                     result-type)))
-                  (if (array-type-p result-ctype)
-                      (let ((dims (array-type-dimensions result-ctype)))
-                        (unless (and (listp dims) (= (length dims) 1))
-                          (give-up-ir1-transform "invalid sequence type"))
-                        (let ((dim (first dims)))
-                          (if (eq dim '*)
-                              bare
-                              `(vector-of-checked-length-given-length ,bare
-                                                                      ,dim))))
-                      ;; FIXME: this is wrong, as not all subtypes of
-                      ;; VECTOR are ARRAY-TYPEs [consider, for
-                      ;; example, (OR (VECTOR T 3) (VECTOR T
-                      ;; 4))]. However, it's difficult to see what we
-                      ;; should put here... maybe we should
-                      ;; GIVE-UP-IR1-TRANSFORM if the type is a
-                      ;; subtype of VECTOR but not an ARRAY-TYPE?
-                      bare))))))))
+         ,(cond ((policy node (< safety 3))
+                 ;; ANSI requires the length-related type check only
+                 ;; when the SAFETY quality is 3... in other cases, we
+                 ;; skip it, because it could be expensive.
+                 bare)
+                ((not constant-result-type-arg-p)
+                 `(sequence-of-checked-length-given-type ,bare
+                                                         result-type-arg))
+                (t
+                 (let ((result-ctype (ir1-transform-specifier-type
+                                      result-type)))
+                   (if (array-type-p result-ctype)
+                       (let ((dims (array-type-dimensions result-ctype)))
+                         (unless (and (listp dims) (= (length dims) 1))
+                           (give-up-ir1-transform "invalid sequence type"))
+                         (let ((dim (first dims)))
+                           (if (eq dim '*)
+                               bare
+                               `(vector-of-checked-length-given-length ,bare
+                                                                       ,dim))))
+                       ;; FIXME: this is wrong, as not all subtypes of
+                       ;; VECTOR are ARRAY-TYPEs [consider, for
+                       ;; example, (OR (VECTOR T 3) (VECTOR T
+                       ;; 4))]. However, it's difficult to see what we
+                       ;; should put here... maybe we should
+                       ;; GIVE-UP-IR1-TRANSFORM if the type is a
+                       ;; subtype of VECTOR but not an ARRAY-TYPE?
+                       bare))))))))
 
 ;;; Return a DO loop, mapping a function FUN to elements of
-;;; sequences. SEQS is a list of continuations, SEQ-NAMES - list of
-;;; variables, bound to sequences, INTO - a variable, which is used in
+;;; sequences. SEQS is a list of lvars, SEQ-NAMES - list of variables,
+;;; bound to sequences, INTO - a variable, which is used in
 ;;; MAP-INTO. RESULT and BODY are forms, which can use variables
 ;;; FUNCALL-RESULT, containing the result of application of FUN, and
 ;;; INDEX, containing the current position in sequences.
   (declare (type list seqs seq-names)
            (type symbol into))
   (collect ((bindings)
-           (declarations)
+            (declarations)
             (vector-lengths)
             (tests)
             (places))
                  (bindings `(index 0 (1+ index)))
                  (declarations `(type index index)))
                (vector-lengths length)))
-        (loop for seq of-type continuation in seqs
+        (loop for seq of-type lvar in seqs
            for seq-name in seq-names
-           for type = (continuation-type seq)
+           for type = (lvar-type seq)
            do (cond ((csubtypep type (specifier-type 'list))
-                     (let ((index (gensym "I")))
+                     (with-unique-names (index)
                        (bindings `(,index ,seq-name (cdr ,index)))
                        (declarations `(type list ,index))
                        (places `(car ,index))
                        (tests `(endp ,index))))
                     ((csubtypep type (specifier-type 'vector))
                      (process-vector `(length ,seq-name))
-                     (places `(aref ,seq-name index)))
+                     (places `(locally (declare (optimize (insert-array-bounds-checks 0)))
+                                (aref ,seq-name index))))
                     (t
                      (give-up-ir1-transform
                       "can't determine sequence argument type"))))
           (process-vector `(array-dimension ,into 0))))
       (when found-vector-p
         (bindings `(length (min ,@(vector-lengths))))
-        (tests `(= index length)))
+        (tests `(>= index length)))
       `(do (,@(bindings))
            ((or ,@(tests)) ,result)
          (declare ,@(declarations))
 ;;; the reader, because the code is complicated enough already and I
 ;;; don't happen to need that functionality right now. -- WHN 20000410
 (deftransform %map ((result-type fun seq &rest seqs) * *
-                   :policy (>= speed space))
+                    :policy (>= speed space))
   "open code"
-  (unless (constant-continuation-p result-type)
+  (unless (constant-lvar-p result-type)
     (give-up-ir1-transform "RESULT-TYPE argument not constant"))
   (labels ( ;; 1-valued SUBTYPEP, fails unless second value of SUBTYPEP is true
-          (fn-1subtypep (fn x y)
-            (multiple-value-bind (subtype-p valid-p) (funcall fn x y)
-              (if valid-p
-                  subtype-p
-                  (give-up-ir1-transform
-                   "can't analyze sequence type relationship"))))
-          (1subtypep (x y) (fn-1subtypep #'sb!xc:subtypep x y)))
-    (let* ((result-type-value (continuation-value result-type))
-          (result-supertype (cond ((null result-type-value) 'null)
-                                  ((1subtypep result-type-value 'vector)
-                                   'vector)
-                                  ((1subtypep result-type-value 'list)
-                                   'list)
-                                  (t
-                                   (give-up-ir1-transform
-                                    "can't determine result type")))))
+           (fn-1subtypep (fn x y)
+             (multiple-value-bind (subtype-p valid-p) (funcall fn x y)
+               (if valid-p
+                   subtype-p
+                   (give-up-ir1-transform
+                    "can't analyze sequence type relationship"))))
+           (1subtypep (x y) (fn-1subtypep #'sb!xc:subtypep x y)))
+    (let* ((result-type-value (lvar-value result-type))
+           (result-supertype (cond ((null result-type-value) 'null)
+                                   ((1subtypep result-type-value 'vector)
+                                    'vector)
+                                   ((1subtypep result-type-value 'list)
+                                    'list)
+                                   (t
+                                    (give-up-ir1-transform
+                                     "result type unsuitable")))))
       (cond ((and result-type-value (null seqs))
-            ;; The consing arity-1 cases can be implemented
-            ;; reasonably efficiently as function calls, and the cost
-            ;; of consing should be significantly larger than
-            ;; function call overhead, so we always compile these
-            ;; cases as full calls regardless of speed-versus-space
-            ;; optimization policy.
-            (cond ((subtypep result-type-value 'list)
-                   '(%map-to-list-arity-1 fun seq))
-                  ( ;; (This one can be inefficient due to COERCE, but
-                   ;; the current open-coded implementation has the
-                   ;; same problem.)
-                   (subtypep result-type-value 'vector)
-                   `(coerce (%map-to-simple-vector-arity-1 fun seq)
-                            ',result-type-value))
-                  (t (bug "impossible (?) sequence type"))))
-           (t
-            (let* ((seqs (cons seq seqs))
-                   (seq-args (make-gensym-list (length seqs))))
-              (multiple-value-bind (push-dacc result)
-                  (ecase result-supertype
-                    (null (values nil nil))
-                    (list (values `(push funcall-result acc)
+             ;; The consing arity-1 cases can be implemented
+             ;; reasonably efficiently as function calls, and the cost
+             ;; of consing should be significantly larger than
+             ;; function call overhead, so we always compile these
+             ;; cases as full calls regardless of speed-versus-space
+             ;; optimization policy.
+             (cond ((subtypep result-type-value 'list)
+                    '(%map-to-list-arity-1 fun seq))
+                   ( ;; (This one can be inefficient due to COERCE, but
+                    ;; the current open-coded implementation has the
+                    ;; same problem.)
+                    (subtypep result-type-value 'vector)
+                    `(coerce (%map-to-simple-vector-arity-1 fun seq)
+                             ',result-type-value))
+                   (t (bug "impossible (?) sequence type"))))
+            (t
+             (let* ((seqs (cons seq seqs))
+                    (seq-args (make-gensym-list (length seqs))))
+               (multiple-value-bind (push-dacc result)
+                   (ecase result-supertype
+                     (null (values nil nil))
+                     (list (values `(push funcall-result acc)
                                    `(nreverse acc)))
-                    (vector (values `(push funcall-result acc)
-                                    `(coerce (nreverse acc)
-                                             ',result-type-value))))
-                ;; (We use the same idiom, of returning a LAMBDA from
-                ;; DEFTRANSFORM, as is used in the DEFTRANSFORMs for
-                ;; FUNCALL and ALIEN-FUNCALL, and for the same
-                ;; reason: we need to get the runtime values of each
-                ;; of the &REST vars.)
-                `(lambda (result-type fun ,@seq-args)
-                   (declare (ignore result-type))
+                     (vector (values `(push funcall-result acc)
+                                     `(coerce (nreverse acc)
+                                              ',result-type-value))))
+                 ;; (We use the same idiom, of returning a LAMBDA from
+                 ;; DEFTRANSFORM, as is used in the DEFTRANSFORMs for
+                 ;; FUNCALL and ALIEN-FUNCALL, and for the same
+                 ;; reason: we need to get the runtime values of each
+                 ;; of the &REST vars.)
+                 `(lambda (result-type fun ,@seq-args)
+                    (declare (ignore result-type))
                     (let ((fun (%coerce-callable-to-fun fun))
                           (acc nil))
                       (declare (type list acc))
          :result '(when (array-has-fill-pointer-p result)
                    (setf (fill-pointer result) index))
          :into 'result
-         :body '(setf (aref result index) funcall-result))
+         :body '(locally (declare (optimize (insert-array-bounds-checks 0)))
+                 (setf (aref result index) funcall-result)))
        result)))
 
 \f
   '(setf (car (nthcdr i s)) v))
 
 (deftransform %check-vector-sequence-bounds ((vector start end)
-                                            (vector * *) *
-                                            :node node)
+                                             (vector * *) *
+                                             :node node)
   (if (policy node (< safety speed))
       '(or end (length vector))
       '(let ((length (length vector)))
-       (if (<= 0 start (or end length) length)
-           (or end length)
-           (sb!impl::signal-bounding-indices-bad-error vector start end)))))
+        (if (<= 0 start (or end length) length)
+            (or end length)
+            (sb!impl::signal-bounding-indices-bad-error vector start end)))))
 
 (macrolet ((def (name)
              `(deftransform ,name ((e l &key (test #'eql)) * *
-                                  :node node)
-                (unless (constant-continuation-p l)
+                                   :node node)
+                (unless (constant-lvar-p l)
                   (give-up-ir1-transform))
 
-                (let ((val (continuation-value l)))
+                (let ((val (lvar-value l)))
                   (unless (policy node
                                   (or (= speed 3)
                                       (and (>= speed space)
                 ;;   if ITEM is not a NUMBER or is a FIXNUM, apply
                 ;;   transform, else give up on transform.
                 (cond (test
-                       (unless (continuation-fun-is test '(eq))
+                       (unless (lvar-fun-is test '(eq))
                          (give-up-ir1-transform)))
-                      ((types-equal-or-intersect (continuation-type item)
+                      ((types-equal-or-intersect (lvar-type item)
                                                  (specifier-type 'number))
                        (give-up-ir1-transform "Item might be a number.")))
                 `(,',eq-fun item list))))
 (deftransform delete-if ((pred list) (t list))
   "open code"
   '(do ((x list (cdr x))
-       (splice '()))
+        (splice '()))
        ((endp x) list)
      (cond ((funcall pred (car x))
-           (if (null splice)
-               (setq list (cdr x))
-               (rplacd splice (cdr x))))
-          (T (setq splice x)))))
+            (if (null splice)
+                (setq list (cdr x))
+                (rplacd splice (cdr x))))
+           (t (setq splice x)))))
 
 (deftransform fill ((seq item &key (start 0) (end (length seq)))
-                   (vector t &key (:start t) (:end index))
-                   *
-                   :policy (> speed space))
+                    (vector t &key (:start t) (:end index))
+                    *
+                    :policy (> speed space))
   "open code"
   (let ((element-type (upgraded-element-type-specifier-or-give-up seq)))
-    (values 
+    (values
      `(with-array-data ((data seq)
-                       (start start)
-                       (end end))
+                        (start start)
+                        (end end))
        (declare (type (simple-array ,element-type 1) data))
        (declare (type fixnum start end))
        (do ((i start (1+ i)))
-          ((= i end) seq)
-        (declare (type index i))
-        ;; WITH-ARRAY-DATA did our range checks once and for all, so
-        ;; it'd be wasteful to check again on every AREF...
-        (declare (optimize (safety 0))) 
-        (setf (aref data i) item)))
+           ((= i end) seq)
+         (declare (type index i))
+         ;; WITH-ARRAY-DATA did our range checks once and for all, so
+         ;; it'd be wasteful to check again on every AREF...
+         (declare (optimize (safety 0)))
+         (setf (aref data i) item)))
      ;; ... though we still need to check that the new element can fit
      ;; into the vector in safe code. -- CSR, 2002-07-05
      `((declare (type ,element-type item))))))
 \f
 ;;;; utilities
 
-;;; Return true if CONT's only use is a non-NOTINLINE reference to a
+;;; Return true if LVAR's only use is a non-NOTINLINE reference to a
 ;;; global function with one of the specified NAMES.
-(defun continuation-fun-is (cont names)
-  (declare (type continuation cont) (list names))
-  (let ((use (continuation-use cont)))
+(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 CONT is a constant continuation, the return the constant value.
-;;; If it is null, then return default, otherwise quietly give up the
-;;; IR1 transform.
+         (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 (cont &optional default)
-  (declare (type (or continuation null) cont))
-  (cond ((not cont) default)
-       ((constant-continuation-p cont)
-        (continuation-value cont))
-       (t
-        (give-up-ir1-transform))))
+(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))))
 
 ;;; FIXME: Why is this code commented out? (Why *was* it commented
 ;;; out? We inherited this situation from cmucl-2.4.8, with no
 ;;; the argument (which should be referenced in any expansion), and
 ;;; the continuation for that argument (or NIL if unsupplied.)
 (defstruct (arg (:constructor %make-arg (name cont))
-               (:copier nil))
+                (:copier nil))
   (name nil :type symbol)
   (cont nil :type (or continuation null)))
 (defmacro make-arg (name)
   (declare (type (or arg null) arg))
   (if (and arg (arg-cont arg))
       (let ((cont (arg-cont arg)))
-       (unless (constant-continuation-p cont)
-         (give-up-ir1-transform "Argument is not constant: ~S."
-                                (arg-name arg)))
-       (continuation-value from-end))
+        (unless (constant-continuation-p cont)
+          (give-up-ir1-transform "Argument is not constant: ~S."
+                                 (arg-name arg)))
+        (continuation-value from-end))
       default))
 
 ;;; If Arg is a constant and is EQL to X, then return T, otherwise NIL. If
   (declare (type (or arg null) x))
   (if (and arg (arg-cont arg))
       (let ((cont (arg-cont arg)))
-       (and (constant-continuation-p cont)
-            (eql (continuation-value cont) x)))
+        (and (constant-continuation-p cont)
+             (eql (continuation-value cont) x)))
       (eql default x)))
 
 (defstruct (iterator (:copier nil))
 ;;; the iteration is forward or backward, then GIVE-UP.
 (defun make-sequence-iterator (sequence type &key start end from-end index)
   (declare (symbol sequence) (type ctype type)
-          (type (or arg null) start end from-end)
-          (type (or symbol null) index))
+           (type (or arg null) start end from-end)
+           (type (or symbol null) index))
   (let ((from-end (arg-constant-value from-end nil)))
     (cond ((csubtypep type (specifier-type 'vector))
-          (let* ((n-stop (gensym))
-                 (n-idx (or index (gensym)))
-                 (start (default-arg 0 start))
-                 (end (default-arg `(length ,sequence) end)))
-            (make-iterator
-             :kind :normal
-             :binds `((,n-idx ,(if from-end `(1- ,end) ,start))
-                      (,n-stop ,(if from-end `(1- ,start) ,end)))
-             :decls `((type neg-index ,n-idx ,n-stop))
-             :current `(aref ,sequence ,n-idx)
-             :done `(,(if from-end '<= '>=) ,n-idx ,n-stop)
-             :next `(setq ,n-idx
-                          ,(if from-end `(1- ,n-idx) `(1+ ,n-idx)))
-             :length (if from-end
-                         `(- ,n-idx ,n-stop)
-                         `(- ,n-stop ,n-idx)))))
-         ((csubtypep type (specifier-type 'list))
-          (let* ((n-stop (if (and end (not from-end)) (gensym) nil))
-                 (n-current (gensym))
-                 (start-p (not (arg-eql start 0 0)))
-                 (end-p (not (arg-eql end nil nil)))
-                 (start (default-arg start 0))
-                 (end (default-arg end nil)))
-            (make-iterator
-             :binds `((,n-current
-                       ,(if from-end
-                            (if (or start-p end-p)
-                                `(nreverse (subseq ,sequence ,start
-                                                   ,@(when end `(,end))))
-                                `(reverse ,sequence))
-                            (if start-p
-                                `(nthcdr ,start ,sequence)
-                                sequence)))
-                      ,@(when n-stop
-                          `((,n-stop (nthcdr (the index
-                                                  (- ,end ,start))
-                                             ,n-current))))
-                      ,@(when index
-                          `((,index ,(if from-end `(1- ,end) start)))))
-             :kind :normal
-             :decls `((list ,n-current ,n-end)
-                      ,@(when index `((type neg-index ,index))))
-             :current `(car ,n-current)
-             :done `(eq ,n-current ,n-stop)
-             :length `(- ,(or end `(length ,sequence)) ,start)
-             :next `(progn
-                      (setq ,n-current (cdr ,n-current))
-                      ,@(when index
-                          `((setq ,n-idx
-                                  ,(if from-end
-                                       `(1- ,index)
-                                       `(1+ ,index)))))))))
-         (t
-          (give-up-ir1-transform
-           "can't tell whether sequence is a list or a vector")))))
+           (let* ((n-stop (gensym))
+                  (n-idx (or index (gensym)))
+                  (start (default-arg 0 start))
+                  (end (default-arg `(length ,sequence) end)))
+             (make-iterator
+              :kind :normal
+              :binds `((,n-idx ,(if from-end `(1- ,end) ,start))
+                       (,n-stop ,(if from-end `(1- ,start) ,end)))
+              :decls `((type neg-index ,n-idx ,n-stop))
+              :current `(aref ,sequence ,n-idx)
+              :done `(,(if from-end '<= '>=) ,n-idx ,n-stop)
+              :next `(setq ,n-idx
+                           ,(if from-end `(1- ,n-idx) `(1+ ,n-idx)))
+              :length (if from-end
+                          `(- ,n-idx ,n-stop)
+                          `(- ,n-stop ,n-idx)))))
+          ((csubtypep type (specifier-type 'list))
+           (let* ((n-stop (if (and end (not from-end)) (gensym) nil))
+                  (n-current (gensym))
+                  (start-p (not (arg-eql start 0 0)))
+                  (end-p (not (arg-eql end nil nil)))
+                  (start (default-arg start 0))
+                  (end (default-arg end nil)))
+             (make-iterator
+              :binds `((,n-current
+                        ,(if from-end
+                             (if (or start-p end-p)
+                                 `(nreverse (subseq ,sequence ,start
+                                                    ,@(when end `(,end))))
+                                 `(reverse ,sequence))
+                             (if start-p
+                                 `(nthcdr ,start ,sequence)
+                                 sequence)))
+                       ,@(when n-stop
+                           `((,n-stop (nthcdr (the index
+                                                   (- ,end ,start))
+                                              ,n-current))))
+                       ,@(when index
+                           `((,index ,(if from-end `(1- ,end) start)))))
+              :kind :normal
+              :decls `((list ,n-current ,n-end)
+                       ,@(when index `((type neg-index ,index))))
+              :current `(car ,n-current)
+              :done `(eq ,n-current ,n-stop)
+              :length `(- ,(or end `(length ,sequence)) ,start)
+              :next `(progn
+                       (setq ,n-current (cdr ,n-current))
+                       ,@(when index
+                           `((setq ,n-idx
+                                   ,(if from-end
+                                        `(1- ,index)
+                                        `(1+ ,index)))))))))
+          (t
+           (give-up-ir1-transform
+            "can't tell whether sequence is a list or a vector")))))
 
 ;;; Make an iterator used for constructing result sequences. Name is a
 ;;; variable to be bound to the result sequence. Type is the type of result
   #!+sb-doc
   "COERCE-FUNCTIONS ({(Name Fun-Arg Default)}*) Form*"
   (collect ((binds)
-           (defs))
+            (defs))
     (dolist (spec specs)
       `(let ((body (progn ,@body))
-            (n-fun (arg-name ,(second spec)))
-            (fun-cont (arg-cont ,(second spec))))
-        (cond ((not fun-cont)
-               `(macrolet ((,',(first spec) (&rest args)
-                            `(,',',(third spec) ,@args)))
-                  ,body))
-              ((not (csubtypep (continuation-type fun-cont)
-                               (specifier-type 'function)))
-               (when (policy *compiler-error-context*
-                             (> speed inhibit-warnings))
-                 (compiler-note
-                  "~S may not be a function, so must coerce at run-time."
-                  n-fun))
-               (once-only ((n-fun `(if (functionp ,n-fun)
-                                       ,n-fun
-                                       (symbol-function ,n-fun))))
-                 `(macrolet ((,',(first spec) (&rest args)
-                              `(funcall ,',n-fun ,@args)))
-                    ,body)))
-              (t
-               `(macrolet ((,',(first spec) (&rest args)
-                             `(funcall ,',n-fun ,@args)))
-                  ,body)))))))
+             (n-fun (arg-name ,(second spec)))
+             (fun-cont (arg-cont ,(second spec))))
+         (cond ((not fun-cont)
+                `(macrolet ((,',(first spec) (&rest args)
+                             `(,',',(third spec) ,@args)))
+                   ,body))
+               ((not (csubtypep (continuation-type fun-cont)
+                                (specifier-type 'function)))
+                (when (policy *compiler-error-context*
+                              (> speed inhibit-warnings))
+                  (compiler-notify
+                   "~S may not be a function, so must coerce at run-time."
+                   n-fun))
+                (once-only ((n-fun `(if (functionp ,n-fun)
+                                        ,n-fun
+                                        (symbol-function ,n-fun))))
+                  `(macrolet ((,',(first spec) (&rest args)
+                               `(funcall ,',n-fun ,@args)))
+                     ,body)))
+               (t
+                `(macrolet ((,',(first spec) (&rest args)
+                              `(funcall ,',n-fun ,@args)))
+                   ,body)))))))
 
 ;;; Wrap code around the result of the body to define Name as a local macro
 ;;; that returns true when its arguments satisfy the test according to the Args
   `(let ((not-p (arg-cont ,test-not)))
      (when (and (arg-cont ,test) not-p)
        (abort-ir1-transform "Both ~S and ~S were supplied."
-                           (arg-name ,test)
-                           (arg-name ,test-not)))
+                            (arg-name ,test)
+                            (arg-name ,test-not)))
      (coerce-funs ((,name (if not-p ,test-not ,test) eql))
        ,@body)))
 |#
 ;;; Return a form that tests the free variables STRING1 and STRING2
 ;;; for the ordering relationship specified by LESSP and EQUALP. The
 ;;; start and end are also gotten from the environment. Both strings
-;;; must be SIMPLE-STRINGs.
+;;; must be SIMPLE-BASE-STRINGs.
 (macrolet ((def (name lessp equalp)
              `(deftransform ,name ((string1 string2 start1 end1 start2 end2)
-                                    (simple-string simple-string t t t t) *)
+                                   (simple-base-string simple-base-string t t t t) *)
                 `(let* ((end1 (if (not end1) (length string1) end1))
                         (end2 (if (not end2) (length string2) end2))
                         (index (sb!impl::%sp-string-compare
                                 string1 start1 end1 string2 start2 end2)))
                   (if index
-                      (cond ((= index ,(if ',lessp 'end1 'end2)) index)
-                            ((= index ,(if ',lessp 'end2 'end1)) nil)
+                      (cond ((= index end1)
+                             ,(if ',lessp 'index nil))
+                            ((= (+ index (- start2 start1)) end2)
+                             ,(if ',lessp nil 'index))
                             ((,(if ',lessp 'char< 'char>)
                                (schar string1 index)
                                (schar string2
                                                  (+ index
                                                     (truly-the fixnum
                                                                (- start2
-                                                                 start1))))))
+                                                                  start1))))))
                              index)
                             (t nil))
                       ,(if ',equalp 'end1 nil))))))
 
 (macrolet ((def (name result-fun)
              `(deftransform ,name ((string1 string2 start1 end1 start2 end2)
-                                   (simple-string simple-string t t t t) *)
+                                   (simple-base-string simple-base-string t t t t) *)
                 `(,',result-fun
                   (sb!impl::%sp-string-compare
                    string1 start1 (or end1 (length string1))
 ;;;; type dispatch in AREF. The exception is CONCATENATE, since
 ;;;; a full call to CONCATENATE would have to look up the sequence
 ;;;; type, which can be really slow.
-;;;;
-;;;; FIXME: It would be nicer for these transforms to work for any
-;;;; calls when all arguments are vectors with the same element type,
-;;;; rather than restricting them to STRINGs only.
 
 ;;; Moved here from generic/vm-tran.lisp to satisfy clisp
 ;;;
 (def!constant vector-data-bit-offset
   (* sb!vm:vector-data-offset sb!vm:n-word-bits))
 
-(deftransform replace ((string1 string2 &key (start1 0) (start2 0)
-                               end1 end2)
-                      (simple-string simple-string &rest t)
-                      *
-                      ;; FIXME: consider replacing this policy test
-                      ;; with some tests for the STARTx and ENDx
-                      ;; indices being valid, conditional on high
-                      ;; SAFETY code.
-                      ;;
-                      ;; FIXME: It turns out that this transform is
-                      ;; critical for the performance of string
-                      ;; streams.  Make this more explicit.
-                      :policy (< (max safety space) 3))
-  `(locally
-     (declare (optimize (safety 0)))
-     (bit-bash-copy string2
-                   (the index
-                        (+ (the index (* start2 sb!vm:n-byte-bits))
-                           ,vector-data-bit-offset))
-                   string1
-                   (the index
-                        (+ (the index (* start1 sb!vm:n-byte-bits))
-                           ,vector-data-bit-offset))
-                   (the index
-                        (* (min (the index (- (or end1 (length string1))
-                                              start1))
-                                (the index (- (or end2 (length string2))
-                                              start2)))
-                           sb!vm:n-byte-bits)))
-     string1))
+(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: It turns out that this transform (for SIMPLE-BASE-STRINGS)
+;; is critical for the performance of string streams.  Make this
+;; more explicit.
+(macrolet
+    ((define-replace-transforms ()
+       (loop for saetp across sb!vm:*specialized-array-element-type-properties*
+             when (valid-bit-bash-saetp-p saetp)
+             collect
+             (let* ((sequence-type `(simple-array ,(sb!vm:saetp-specifier saetp) (*)))
+                    (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"))))
+               `(deftransform replace ((seq1 seq2 &key (start1 0) (start2 0) end1 end2)
+                                       (,sequence-type ,sequence-type &rest t)
+                                       ,sequence-type
+                                       :node node)
+                 `(let* ((len1 (length seq1))
+                         (len2 (length seq2))
+                         (end1 (or end1 len1))
+                         (end2 (or end2 len2))
+                         (replace-len1 (- end1 start1))
+                         (replace-len2 (- end2 start2)))
+                   ,(unless (policy node (= safety 0))
+                     `(progn
+                       (unless (<= 0 start1 end1 len1)
+                         (sb!impl::signal-bounding-indices-bad-error seq1 start1 end1))
+                       (unless (<= 0 start2 end2 len2)
+                         (sb!impl::signal-bounding-indices-bad-error seq2 start2 end2))))
+                   (funcall (function ,',bash-function)
+                    seq2 start2
+                    seq1 start1
+                    (min replace-len1 replace-len2))
+                   seq1)))
+             into forms
+             finally (return `(progn ,@forms)))))
+  (define-replace-transforms))
+
+(macrolet
+    ((define-subseq-transforms ()
+       (loop for saetp across sb!vm:*specialized-array-element-type-properties*
+             when (valid-bit-bash-saetp-p saetp)
+             collect
+             (let* ((sequence-type `(simple-array ,(sb!vm:saetp-specifier saetp) (*)))
+                    (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"))))
+               `(deftransform subseq ((seq start &optional end)
+                                      (,sequence-type t &optional t)
+                                      ,sequence-type :node node)
+                 `(let* ((length (length seq))
+                         (end (if end (min end length) length)))
+                   ,(unless (policy node (= safety 0))
+                     `(progn
+                       (unless (<= 0 start end length)
+                         (sb!impl::signal-bounding-indices-bad-error seq start end))))
+                   (let* ((size (- end start))
+                          (result (make-array size :element-type ',',(sb!vm:saetp-specifier saetp))))
+                     (funcall (function ,',bash-function)
+                              seq start result 0 size)
+                     result))))
+             into forms
+             finally (return `(progn ,@forms)))))
+  (define-subseq-transforms))
+
+(macrolet
+    ((define-copy-seq-transforms ()
+       (loop for saetp across sb!vm:*specialized-array-element-type-properties*
+             when (valid-bit-bash-saetp-p saetp)
+             collect
+             (let* ((sequence-type `(simple-array ,(sb!vm:saetp-specifier saetp) (*)))
+                    (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"))))
+               `(deftransform copy-seq ((seq) (,sequence-type)
+                                        ,sequence-type)
+                 `(let* ((length (length seq))
+                         (result (make-array length :element-type ',',(sb!vm:saetp-specifier saetp))))
+                   (funcall (function ,',bash-function)
+                    seq 0 result 0 length)
+                   result)))
+             into forms
+             finally (return `(progn ,@forms)))))
+  (define-copy-seq-transforms))
+
+;;; FIXME: this would be a valid transform for certain excluded cases:
+;;;   * :TEST 'CHAR= or :TEST #'CHAR=
+;;;   * :TEST 'EQL   or :TEST #'EQL
+;;;   * :FROM-END NIL (or :FROM-END non-NIL, with a little ingenuity)
+(deftransform search ((pattern text &key (start1 0) (start2 0) end1 end2)
+                      (simple-string simple-string &rest t)
+                      *
+                      :policy (> speed (max space safety)))
+  `(block search
+    (let ((end1 (or end1 (length pattern)))
+          (end2 (or end2 (length text))))
+      (do ((index2 start2 (1+ index2)))
+          ((>= index2 end2) nil)
+        (when (do ((index1 start1 (1+ index1))
+                   (index2 index2 (1+ index2)))
+                  ((>= index1 end1) t)
+                (when (= index2 end2)
+                  (return-from search nil))
+                (when (char/= (char pattern index1) (char text index2))
+                  (return nil)))
+          (return index2))))))
 
 ;;; FIXME: It seems as though it should be possible to make a DEFUN
 ;;; %CONCATENATE (with a DEFTRANSFORM to translate constant RTYPE to
 ;;; at least once DYNAMIC-EXTENT works.
 ;;;
 ;;; FIXME: currently KLUDGEed because of bug 188
+;;;
+;;; FIXME: disabled for sb-unicode: probably want it back
+#!-sb-unicode
 (deftransform concatenate ((rtype &rest sequences)
-                          (t &rest simple-string)
-                          simple-string
-                          :policy (< safety 3))
-  (collect ((lets)
-           (forms)
-           (all-lengths)
-           (args))
-    (dolist (seq sequences)
-      (declare (ignorable seq))
-      (let ((n-seq (gensym))
-           (n-length (gensym)))
-       (args n-seq)
-       (lets `(,n-length (the index (* (length ,n-seq) sb!vm:n-byte-bits))))
-       (all-lengths n-length)
-       (forms `(bit-bash-copy ,n-seq ,vector-data-bit-offset
-                              res start
-                              ,n-length))
-       (forms `(setq start (opaque-identity (+ start ,n-length))))))
-    `(lambda (rtype ,@(args))
-       (declare (ignore rtype))
-       ;; KLUDGE
-       (flet ((opaque-identity (x) x))
-        (declare (notinline opaque-identity))
-        (let* (,@(lets)
-                 (res (make-string (truncate (the index (+ ,@(all-lengths)))
-                                             sb!vm:n-byte-bits)))
-                 (start ,vector-data-bit-offset))
-          (declare (type index start ,@(all-lengths)))
-          ,@(forms)
-          res)))))
+                           (t &rest (or simple-base-string
+                                        (simple-array nil (*))))
+                           simple-base-string
+                           :policy (< safety 3))
+  (loop for rest-seqs on sequences
+        for n-seq = (gensym "N-SEQ")
+        for n-length = (gensym "N-LENGTH")
+        for start = 0 then next-start
+        for next-start = (gensym "NEXT-START")
+        collect n-seq into args
+        collect `(,n-length (length ,n-seq)) into lets
+        collect n-length into all-lengths
+        collect next-start into starts
+        collect `(if (and (typep ,n-seq '(simple-array nil (*)))
+                          (> ,n-length 0))
+                     (error 'nil-array-accessed-error)
+                     (#.(let* ((i (position 'character sb!kernel::*specialized-array-element-types*))
+                               (saetp (aref sb!vm:*specialized-array-element-type-properties* i))
+                               (n-bits (sb!vm:saetp-n-bits saetp)))
+                          (intern (format nil "UB~D-BASH-COPY" n-bits)
+                                  "SB!KERNEL"))
+                        ,n-seq 0 res ,start ,n-length))
+                into forms
+        collect `(setq ,next-start (+ ,start ,n-length)) into forms
+        finally
+        (return
+          `(lambda (rtype ,@args)
+             (declare (ignore rtype))
+             (let* (,@lets
+                    (res (make-string (the index (+ ,@all-lengths))
+                                      :element-type 'base-char)))
+               (declare (type index ,@all-lengths))
+               (let (,@(mapcar (lambda (name) `(,name 0)) starts))
+                 (declare (type index ,@starts))
+                 ,@forms)
+               res)))))
 \f
 ;;;; CONS accessor DERIVE-TYPE optimizers
 
 (defoptimizer (car derive-type) ((cons))
-  (let ((type (continuation-type cons))
-       (null-type (specifier-type 'null)))
+  (let ((type (lvar-type cons))
+        (null-type (specifier-type 'null)))
     (cond ((eq type null-type)
-          null-type)
-         ((cons-type-p type)
-          (cons-type-car-type type)))))
+           null-type)
+          ((cons-type-p type)
+           (cons-type-car-type type)))))
 
 (defoptimizer (cdr derive-type) ((cons))
-  (let ((type (continuation-type cons))
-       (null-type (specifier-type 'null)))
+  (let ((type (lvar-type cons))
+        (null-type (specifier-type 'null)))
     (cond ((eq type null-type)
-          null-type)
-         ((cons-type-p type)
-          (cons-type-cdr-type type)))))
+           null-type)
+          ((cons-type-p type)
+           (cons-type-cdr-type type)))))
 \f
 ;;;; FIND, POSITION, and their -IF and -IF-NOT variants
 
 ;;; %FIND-POSITION-IF only when %FIND-POSITION-IF has an inline
 ;;; expansion, so we factor out the condition into this function.
 (defun check-inlineability-of-find-position-if (sequence from-end)
-  (let ((ctype (continuation-type sequence)))
+  (let ((ctype (lvar-type sequence)))
     (cond ((csubtypep ctype (specifier-type 'vector))
-          ;; It's not worth trying to inline vector code unless we
-          ;; know a fair amount about it at compile time.
-          (upgraded-element-type-specifier-or-give-up sequence)
-          (unless (constant-continuation-p from-end)
-            (give-up-ir1-transform
-             "FROM-END argument value not known at compile time")))
-         ((csubtypep ctype (specifier-type 'list))
-          ;; Inlining on lists is generally worthwhile.
-          ) 
-         (t
-          (give-up-ir1-transform
-           "sequence type not known at compile time")))))
+           ;; It's not worth trying to inline vector code unless we
+           ;; know a fair amount about it at compile time.
+           (upgraded-element-type-specifier-or-give-up sequence)
+           (unless (constant-lvar-p from-end)
+             (give-up-ir1-transform
+              "FROM-END argument value not known at compile time")))
+          ((csubtypep ctype (specifier-type 'list))
+           ;; Inlining on lists is generally worthwhile.
+           )
+          (t
+           (give-up-ir1-transform
+            "sequence type not known at compile time")))))
 
 ;;; %FIND-POSITION-IF and %FIND-POSITION-IF-NOT for LIST data
 (macrolet ((def (name condition)
-            `(deftransform ,name ((predicate sequence from-end start end key)
-                                  (function list t t t function)
-                                  *
-                                  :policy (> speed space)
-                                  :important t)
-               "expand inline"
-               `(let ((index 0)
-                      (find nil)
-                      (position nil))
-                  (declare (type index index))
-                  (dolist (i sequence
-                           (if (and end (> end index))
-                               (sb!impl::signal-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)
-                        (,',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))))))
-                    (incf index))))))
+             `(deftransform ,name ((predicate sequence from-end start end key)
+                                   (function list t t t function)
+                                   *
+                                   :policy (> speed space))
+                "expand inline"
+                `(let ((index 0)
+                       (find nil)
+                       (position nil))
+                   (declare (type index index))
+                   (dolist (i sequence
+                            (if (and end (> end index))
+                                (sb!impl::signal-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)
+                         (,',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))))))
+                     (incf index))))))
   (def %find-position-if when)
   (def %find-position-if-not unless))
-                     
+
 ;;; %FIND-POSITION for LIST data can be expanded into %FIND-POSITION-IF
 ;;; without loss of efficiency. (I.e., the optimizer should be able
 ;;; to straighten everything out.)
 (deftransform %find-position ((item sequence from-end start end key test)
-                             (t list t t t t t)
-                             *
-                             :policy (> speed space)
-                             :important t)
+                              (t list t t t t t)
+                              *
+                              :policy (> speed space))
   "expand inline"
   '(%find-position-if (let ((test-fun (%coerce-callable-to-fun test)))
-                       ;; The order of arguments for asymmetric tests
-                       ;; (e.g. #'<, as opposed to order-independent
-                       ;; tests like #'=) is specified in the spec
-                       ;; section 17.2.1 -- the O/Zi stuff there.
-                       (lambda (i)
-                         (funcall test-fun item i)))
-                     sequence
-                     from-end
-                     start
-                     end
-                     (%coerce-callable-to-fun key)))
+                        ;; The order of arguments for asymmetric tests
+                        ;; (e.g. #'<, as opposed to order-independent
+                        ;; tests like #'=) is specified in the spec
+                        ;; section 17.2.1 -- the O/Zi stuff there.
+                        (lambda (i)
+                          (funcall test-fun item i)))
+                      sequence
+                      from-end
+                      start
+                      end
+                      (%coerce-callable-to-fun key)))
 
 ;;; The inline expansions for the VECTOR case are saved as macros so
 ;;; that we can share them between the DEFTRANSFORMs and the default
 ;;; cases in the DEFUNs. (This isn't needed for the LIST case, because
 ;;; the DEFTRANSFORMs for LIST are less choosy about when to expand.)
 (defun %find-position-or-find-position-if-vector-expansion (sequence-arg
-                                                           from-end
-                                                           start
-                                                           end-arg
-                                                           element
-                                                           done-p-expr)
-  (let ((offset (gensym "OFFSET"))
-       (block (gensym "BLOCK"))
-       (index (gensym "INDEX"))
-       (n-sequence (gensym "N-SEQUENCE-"))
-       (sequence (gensym "SEQUENCE"))
-       (n-end (gensym "N-END-"))
-       (end (gensym "END-")))
+                                                            from-end
+                                                            start
+                                                            end-arg
+                                                            element
+                                                            done-p-expr)
+  (with-unique-names (offset block index n-sequence sequence n-end end)
     `(let ((,n-sequence ,sequence-arg)
-          (,n-end ,end-arg))
+           (,n-end ,end-arg))
        (with-array-data ((,sequence ,n-sequence :offset-var ,offset)
-                        (,start ,start)
-                        (,end (%check-vector-sequence-bounds
-                               ,n-sequence ,start ,n-end)))
+                         (,start ,start)
+                         (,end (%check-vector-sequence-bounds
+                                ,n-sequence ,start ,n-end)))
          (block ,block
-          (macrolet ((maybe-return ()
-                       '(let ((,element (aref ,sequence ,index)))
-                          (when ,done-p-expr
-                            (return-from ,block
-                              (values ,element
-                                      (- ,index ,offset)))))))
-            (if ,from-end
-                (loop for ,index
-                      ;; (If we aren't fastidious about declaring that 
-                      ;; INDEX might be -1, then (FIND 1 #() :FROM-END T)
-                      ;; can send us off into never-never land, since
-                      ;; INDEX is initialized to -1.)
-                      of-type index-or-minus-1
-                      from (1- ,end) downto ,start do
-                      (maybe-return))
-                (loop for ,index of-type index from ,start below ,end do
-                      (maybe-return))))
-          (values nil nil))))))
+           (macrolet ((maybe-return ()
+                        ;; WITH-ARRAY-DATA has already performed bounds
+                        ;; checking, so we can safely elide the checks
+                        ;; in the inner loop.
+                        '(let ((,element (locally (declare (optimize (insert-array-bounds-checks 0)))
+                                           (aref ,sequence ,index))))
+                           (when ,done-p-expr
+                             (return-from ,block
+                               (values ,element
+                                       (- ,index ,offset)))))))
+             (if ,from-end
+                 (loop for ,index
+                       ;; (If we aren't fastidious about declaring that
+                       ;; INDEX might be -1, then (FIND 1 #() :FROM-END T)
+                       ;; can send us off into never-never land, since
+                       ;; INDEX is initialized to -1.)
+                       of-type index-or-minus-1
+                       from (1- ,end) downto ,start do
+                       (maybe-return))
+                 (loop for ,index of-type index from ,start below ,end do
+                       (maybe-return))))
+           (values nil nil))))))
 
 (def!macro %find-position-vector-macro (item sequence
-                                            from-end start end key test)
-  (let ((element (gensym "ELEMENT")))
+                                             from-end start end key test)
+  (with-unique-names (element)
     (%find-position-or-find-position-if-vector-expansion
      sequence
      from-end
      `(funcall ,test ,item (funcall ,key ,element)))))
 
 (def!macro %find-position-if-vector-macro (predicate sequence
-                                                    from-end start end key)
-  (let ((element (gensym "ELEMENT")))
+                                                     from-end start end key)
+  (with-unique-names (element)
     (%find-position-or-find-position-if-vector-expansion
      sequence
      from-end
      `(funcall ,predicate (funcall ,key ,element)))))
 
 (def!macro %find-position-if-not-vector-macro (predicate sequence
-                                                        from-end start end key)
-  (let ((element (gensym "ELEMENT")))
+                                                         from-end start end key)
+  (with-unique-names (element)
     (%find-position-or-find-position-if-vector-expansion
      sequence
      from-end
 ;;; %FIND-POSITION, %FIND-POSITION-IF and %FIND-POSITION-IF-NOT for
 ;;; VECTOR data
 (deftransform %find-position-if ((predicate sequence from-end start end key)
-                                (function vector t t t function)
-                                *
-                                :policy (> speed space)
-                                :important t)
+                                 (function vector t t t function)
+                                 *
+                                 :policy (> speed space))
   "expand inline"
   (check-inlineability-of-find-position-if sequence from-end)
   '(%find-position-if-vector-macro predicate sequence
-                                  from-end start end key))
+                                   from-end start end key))
 
 (deftransform %find-position-if-not ((predicate sequence from-end start end key)
-                                    (function vector t t t function)
-                                    *
-                                    :policy (> speed space)
-                                    :important t)
+                                     (function vector t t t function)
+                                     *
+                                     :policy (> speed space))
   "expand inline"
   (check-inlineability-of-find-position-if sequence from-end)
   '(%find-position-if-not-vector-macro predicate sequence
                                        from-end start end key))
 
 (deftransform %find-position ((item sequence from-end start end key test)
-                             (t vector t t t function function)
-                             *
-                             :policy (> speed space)
-                             :important t)
+                              (t vector t t t function function)
+                              *
+                              :policy (> speed space))
   "expand inline"
   (check-inlineability-of-find-position-if sequence from-end)
   '(%find-position-vector-macro item sequence
-                               from-end start end key test))
+                                from-end start end key test))
 
 ;;; logic to unravel :TEST, :TEST-NOT, and :KEY options in FIND,
 ;;; POSITION-IF, etc.
 (define-source-transform effective-find-position-test (test test-not)
   (once-only ((test test)
-             (test-not test-not))
+              (test-not test-not))
     `(cond
       ((and ,test ,test-not)
        (error "can't specify both :TEST and :TEST-NOT"))
 (define-source-transform effective-find-position-key (key)
   (once-only ((key key))
     `(if ,key
-        (%coerce-callable-to-fun ,key)
-        #'identity)))
+         (%coerce-callable-to-fun ,key)
+         #'identity)))
 
 (macrolet ((define-find-position (fun-name values-index)
-            `(deftransform ,fun-name ((item sequence &key
-                                            from-end (start 0) end
-                                            key test test-not))
-               '(nth-value ,values-index
-                           (%find-position item sequence
-                                           from-end start
-                                           end
-                                           (effective-find-position-key key)
-                                           (effective-find-position-test
-                                            test test-not))))))
+             `(deftransform ,fun-name ((item sequence &key
+                                             from-end (start 0) end
+                                             key test test-not)
+                                       (t (or list vector) &rest t))
+                '(nth-value ,values-index
+                            (%find-position item sequence
+                                            from-end start
+                                            end
+                                            (effective-find-position-key key)
+                                            (effective-find-position-test
+                                             test test-not))))))
   (define-find-position find 0)
   (define-find-position position 1))
 
 (macrolet ((define-find-position-if (fun-name values-index)
-            `(deftransform ,fun-name ((predicate sequence &key
-                                                 from-end (start 0)
-                                                 end key))
-               '(nth-value
-                 ,values-index
-                 (%find-position-if (%coerce-callable-to-fun predicate)
-                                    sequence from-end
-                                    start end
-                                    (effective-find-position-key key))))))
+             `(deftransform ,fun-name ((predicate sequence &key
+                                                  from-end (start 0)
+                                                  end key)
+                                       (t (or list vector) &rest t))
+                '(nth-value
+                  ,values-index
+                  (%find-position-if (%coerce-callable-to-fun predicate)
+                                     sequence from-end
+                                     start end
+                                     (effective-find-position-key key))))))
   (define-find-position-if find-if 0)
   (define-find-position-if position-if 1))
 
 ;;;     perhaps it's worth optimizing the -if-not versions in the same
 ;;;     way as the others?
 ;;;
-;;; FIXME: Maybe remove uses of these deprecated functions (and
-;;; definitely of :TEST-NOT) within the implementation of SBCL.
+;;; FIXME: Maybe remove uses of these deprecated functions within the
+;;; implementation of SBCL.
 (macrolet ((define-find-position-if-not (fun-name values-index)
-              `(deftransform ,fun-name ((predicate sequence &key
-                                         from-end (start 0)
-                                         end key))
-                '(nth-value
-                  ,values-index
-                  (%find-position-if-not (%coerce-callable-to-fun predicate)
-                   sequence from-end
-                   start end
-                   (effective-find-position-key key))))))
+               `(deftransform ,fun-name ((predicate sequence &key
+                                          from-end (start 0)
+                                          end key)
+                                         (t (or list vector) &rest t))
+                 '(nth-value
+                   ,values-index
+                   (%find-position-if-not (%coerce-callable-to-fun predicate)
+                    sequence from-end
+                    start end
+                    (effective-find-position-key key))))))
   (define-find-position-if-not find-if-not 0)
   (define-find-position-if-not position-if-not 1))