src/compiler/generic/vm-tran.lisp

   1 ;;;; implementation-dependent transforms
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!C")
  13
  14 ;;; We need to define these predicates, since the TYPEP source
  15 ;;; transform picks whichever predicate was defined last when there
  16 ;;; are multiple predicates for equivalent types.
  17 (define-source-transform short-float-p (x) `(single-float-p ,x))
  18 #!-long-float
  19 (define-source-transform long-float-p (x) `(double-float-p ,x))
  20
  21 (define-source-transform compiled-function-p (x)
  22   #!-sb-eval
  23   `(functionp ,x)
  24   #!+sb-eval
  25   (once-only ((x x))
  26     `(and (functionp ,x)
  27           (not (sb!eval:interpreted-function-p ,x)))))
  28
  29 (define-source-transform char-int (x)
  30   `(char-code ,x))
  31
  32 (deftransform abs ((x) (rational))
  33   '(if (< x 0) (- x) x))
  34
  35 ;;; We don't want to clutter the bignum code.
  36 #!+(or x86 x86-64)
  37 (define-source-transform sb!bignum:%bignum-ref (bignum index)
  38   ;; KLUDGE: We use TRULY-THE here because even though the bignum code
  39   ;; is (currently) compiled with (SAFETY 0), the compiler insists on
  40   ;; inserting CAST nodes to ensure that INDEX is of the correct type.
  41   ;; These CAST nodes do not generate any type checks, but they do
  42   ;; interfere with the operation of FOLD-INDEX-ADDRESSING, below.
  43   ;; This scenario is a problem for the more user-visible case of
  44   ;; folding as well.  --njf, 2006-12-01
  45   `(sb!bignum:%bignum-ref-with-offset ,bignum
  46                                       (truly-the bignum-index ,index) 0))
  47
  48 #!+(or x86 x86-64)
  49 (defun fold-index-addressing (fun-name element-size lowtag data-offset
  50                               index offset &optional setter-p)
  51   (multiple-value-bind (func index-args) (extract-fun-args index '(+ -) 2)
  52     (destructuring-bind (x constant) index-args
  53       (declare (ignorable x))
  54       (unless (constant-lvar-p constant)
  55         (give-up-ir1-transform))
  56       (let ((value (lvar-value constant)))
  57         (unless (and (integerp value)
  58                      (sb!vm::foldable-constant-offset-p
  59                       element-size lowtag data-offset
  60                       (funcall func value (lvar-value offset))))
  61           (give-up-ir1-transform "constant is too large for inlining"))
  62         (splice-fun-args index func 2)
  63         `(lambda (thing index off1 off2 ,@(when setter-p
  64                                             '(value)))
  65            (,fun-name thing index (,func off2 off1) ,@(when setter-p
  66                                                         '(value))))))))
  67
  68 #!+(or x86 x86-64)
  69 (deftransform sb!bignum:%bignum-ref-with-offset
  70     ((bignum index offset) * * :node node)
  71   (fold-index-addressing 'sb!bignum:%bignum-ref-with-offset
  72                          sb!vm:n-word-bits sb!vm:other-pointer-lowtag
  73                          sb!vm:bignum-digits-offset
  74                          index offset))
  75
  76 ;;; The layout is stored in slot 0.
  77 (define-source-transform %instance-layout (x)
  78   `(truly-the layout (%instance-ref ,x 0)))
  79 (define-source-transform %set-instance-layout (x val)
  80   `(%instance-set ,x 0 (the layout ,val)))
  81 (define-source-transform %funcallable-instance-layout (x)
  82   `(truly-the layout (%funcallable-instance-info ,x 0)))
  83 (define-source-transform %set-funcallable-instance-layout (x val)
  84   `(setf (%funcallable-instance-info ,x 0) (the layout ,val)))
  85 \f
  86 ;;;; character support
  87
  88 ;;; In our implementation there are really only BASE-CHARs.
  89 #+nil
  90 (define-source-transform characterp (obj)
  91   `(base-char-p ,obj))
  92 \f
  93 ;;;; simplifying HAIRY-DATA-VECTOR-REF and HAIRY-DATA-VECTOR-SET
  94
  95 (deftransform hairy-data-vector-ref ((string index) (simple-string t))
  96   (let ((ctype (lvar-type string)))
  97     (if (array-type-p ctype)
  98         ;; the other transform will kick in, so that's OK
  99         (give-up-ir1-transform)
 100         `(etypecase string
 101           ((simple-array character (*))
 102            (data-vector-ref string index))
 103           #!+sb-unicode
 104           ((simple-array base-char (*))
 105            (data-vector-ref string index))
 106           ((simple-array nil (*))
 107            (data-vector-ref string index))))))
 108
 109 ;;; This and the corresponding -SET transform work equally well on non-simple
 110 ;;; arrays, but after benchmarking (on x86), Nikodemus didn't find any cases
 111 ;;; where it actually helped with non-simple arrays -- to the contrary, it
 112 ;;; only made for bigger and up 1o 100% slower code.
 113 (deftransform hairy-data-vector-ref ((array index) (simple-array t) *)
 114   "avoid runtime dispatch on array element type"
 115   (let* ((type (lvar-type array))
 116          (element-ctype (array-type-upgraded-element-type type))
 117          (declared-element-ctype (array-type-declared-element-type type)))
 118     (declare (type ctype element-ctype))
 119     (when (eq *wild-type* element-ctype)
 120       (give-up-ir1-transform
 121        "Upgraded element type of array is not known at compile time."))
 122     ;; (The expansion here is basically a degenerate case of
 123     ;; WITH-ARRAY-DATA. Since WITH-ARRAY-DATA is implemented as a
 124     ;; macro, and macros aren't expanded in transform output, we have
 125     ;; to hand-expand it ourselves.)
 126     (let* ((element-type-specifier (type-specifier element-ctype)))
 127       `(multiple-value-bind (array index)
 128            (%data-vector-and-index array index)
 129          (declare (type (simple-array ,element-type-specifier 1) array))
 130          ,(let ((bare-form '(data-vector-ref array index)))
 131             (if (type= element-ctype declared-element-ctype)
 132                 bare-form
 133                 `(the ,(type-specifier declared-element-ctype)
 134                       ,bare-form)))))))
 135
 136 ;;; Transform multi-dimensional array to one dimensional data vector
 137 ;;; access.
 138 (deftransform data-vector-ref ((array index) (simple-array t))
 139   (let ((array-type (lvar-type array)))
 140     (unless (array-type-p array-type)
 141       (give-up-ir1-transform))
 142     (let ((dims (array-type-dimensions array-type)))
 143       (when (or (atom dims) (= (length dims) 1))
 144         (give-up-ir1-transform))
 145       (let ((el-type (array-type-specialized-element-type array-type))
 146             (total-size (if (member '* dims)
 147                             '*
 148                             (reduce #'* dims))))
 149         `(data-vector-ref (truly-the (simple-array ,(type-specifier el-type)
 150                                                    (,total-size))
 151                                      (%array-data-vector array))
 152                           index)))))
 153
 154 ;;; Transform data vector access to a form that opens up optimization
 155 ;;; opportunities. On platforms that support DATA-VECTOR-REF-WITH-OFFSET
 156 ;;; DATA-VECTOR-REF is not supported at all.
 157 #!+(or x86 x86-64)
 158 (define-source-transform data-vector-ref (array index)
 159   `(data-vector-ref-with-offset ,array ,index 0))
 160
 161 #!+(or x86 x86-64)
 162 (deftransform data-vector-ref-with-offset ((array index offset))
 163   (let ((array-type (lvar-type array)))
 164     (when (or (not (array-type-p array-type))
 165               (eql (array-type-specialized-element-type array-type)
 166                    *wild-type*))
 167       (give-up-ir1-transform))
 168     ;; It shouldn't be possible to get here with anything but a non-complex
 169     ;; vector.
 170     (aver (not (array-type-complexp array-type)))
 171     (let* ((element-type (type-specifier (array-type-specialized-element-type array-type)))
 172            (saetp (find-saetp element-type)))
 173       (when (< (sb!vm:saetp-n-bits saetp) sb!vm:n-byte-bits)
 174         (give-up-ir1-transform))
 175       (fold-index-addressing 'data-vector-ref-with-offset
 176                              (sb!vm:saetp-n-bits saetp)
 177                              sb!vm:other-pointer-lowtag
 178                              sb!vm:vector-data-offset
 179                              index offset))))
 180
 181 (deftransform hairy-data-vector-set ((string index new-value)
 182                                      (simple-string t t))
 183   (let ((ctype (lvar-type string)))
 184     (if (array-type-p ctype)
 185         ;; the other transform will kick in, so that's OK
 186         (give-up-ir1-transform)
 187         `(etypecase string
 188           ((simple-array character (*))
 189            (data-vector-set string index new-value))
 190           #!+sb-unicode
 191           ((simple-array base-char (*))
 192            (data-vector-set string index new-value))
 193           ((simple-array nil (*))
 194            (data-vector-set string index new-value))))))
 195
 196 ;;; This and the corresponding -REF transform work equally well on non-simple
 197 ;;; arrays, but after benchmarking (on x86), Nikodemus didn't find any cases
 198 ;;; where it actually helped with non-simple arrays -- to the contrary, it
 199 ;;; only made for bigger and up 1o 100% slower code.
 200 (deftransform hairy-data-vector-set ((array index new-value)
 201                                      (simple-array t t)
 202                                      *)
 203   "avoid runtime dispatch on array element type"
 204   (let* ((type (lvar-type array))
 205          (element-ctype (array-type-upgraded-element-type type))
 206          (declared-element-ctype (array-type-declared-element-type type)))
 207     (declare (type ctype element-ctype))
 208     (when (eq *wild-type* element-ctype)
 209       (give-up-ir1-transform
 210        "Upgraded element type of array is not known at compile time."))
 211     (let ((element-type-specifier (type-specifier element-ctype)))
 212       `(multiple-value-bind (array index)
 213            (%data-vector-and-index array index)
 214          (declare (type (simple-array ,element-type-specifier 1) array)
 215                   (type ,element-type-specifier new-value))
 216          ,(if (type= element-ctype declared-element-ctype)
 217               '(data-vector-set array index new-value)
 218               `(truly-the ,(type-specifier declared-element-ctype)
 219                  (data-vector-set array index
 220                   (the ,(type-specifier declared-element-ctype)
 221                        new-value))))))))
 222
 223 ;;; Transform multi-dimensional array to one dimensional data vector
 224 ;;; access.
 225 (deftransform data-vector-set ((array index new-value)
 226                                (simple-array t t))
 227   (let ((array-type (lvar-type array)))
 228     (unless (array-type-p array-type)
 229       (give-up-ir1-transform))
 230     (let ((dims (array-type-dimensions array-type)))
 231       (when (or (atom dims) (= (length dims) 1))
 232         (give-up-ir1-transform))
 233       (let ((el-type (array-type-specialized-element-type array-type))
 234             (total-size (if (member '* dims)
 235                             '*
 236                             (reduce #'* dims))))
 237         `(data-vector-set (truly-the (simple-array ,(type-specifier el-type)
 238                                                    (,total-size))
 239                                      (%array-data-vector array))
 240                           index
 241                           new-value)))))
 242
 243 ;;; Transform data vector access to a form that opens up optimization
 244 ;;; opportunities.
 245 #!+(or x86 x86-64)
 246 (define-source-transform data-vector-set (array index new-value)
 247   `(data-vector-set-with-offset ,array ,index 0 ,new-value))
 248
 249 #!+(or x86 x86-64)
 250 (deftransform data-vector-set-with-offset ((array index offset new-value))
 251   (let ((array-type (lvar-type array)))
 252     (when (or (not (array-type-p array-type))
 253               (eql (array-type-specialized-element-type array-type)
 254                    *wild-type*))
 255       ;; We don't yet know the exact element type, but will get that
 256       ;; knowledge after some more type propagation.
 257       (give-up-ir1-transform))
 258     (aver (not (array-type-complexp array-type)))
 259     (let* ((element-type (type-specifier (array-type-specialized-element-type array-type)))
 260            (saetp (find-saetp element-type)))
 261       (when (< (sb!vm:saetp-n-bits saetp) sb!vm:n-byte-bits)
 262         (give-up-ir1-transform))
 263       (fold-index-addressing 'data-vector-set-with-offset
 264                              (sb!vm:saetp-n-bits saetp)
 265                              sb!vm:other-pointer-lowtag
 266                              sb!vm:vector-data-offset
 267                              index offset t))))
 268
 269 (defun maybe-array-data-vector-type-specifier (array-lvar)
 270   (let ((atype (lvar-type array-lvar)))
 271     (when (array-type-p atype)
 272       (let ((dims (array-type-dimensions atype)))
 273         (if (or (array-type-complexp atype)
 274                 (eq '* dims)
 275                 (notevery #'integerp dims))
 276            `(simple-array ,(type-specifier
 277                             (array-type-specialized-element-type atype))
 278                           (*))
 279            `(simple-array ,(type-specifier
 280                             (array-type-specialized-element-type atype))
 281                           (,(apply #'* dims))))))))
 282
 283 (macrolet ((def (name)
 284              `(defoptimizer (,name derive-type) ((array-lvar))
 285                 (let ((spec (maybe-array-data-vector-type-specifier array-lvar)))
 286                   (when spec
 287                     (specifier-type spec))))))
 288   (def %array-data-vector)
 289   (def array-storage-vector))
 290
 291 (defoptimizer (%data-vector-and-index derive-type) ((array index))
 292   (let ((spec (maybe-array-data-vector-type-specifier array)))
 293     (when spec
 294       (values-specifier-type `(values ,spec index)))))
 295
 296 (deftransform %data-vector-and-index ((%array %index)
 297                                       (simple-array t)
 298                                       *)
 299   ;; KLUDGE: why the percent signs?  Well, ARRAY and INDEX are
 300   ;; respectively exported from the CL and SB!INT packages, which
 301   ;; means that they're visible to all sorts of things.  If the
 302   ;; compiler can prove that the call to ARRAY-HEADER-P, below, either
 303   ;; returns T or NIL, it will delete the irrelevant branch.  However,
 304   ;; user code might have got here with a variable named CL:ARRAY, and
 305   ;; quite often compiler code with a variable named SB!INT:INDEX, so
 306   ;; this can generate code deletion notes for innocuous user code:
 307   ;; (DEFUN F (ARRAY I) (DECLARE (SIMPLE-VECTOR ARRAY)) (AREF ARRAY I))
 308   ;; -- CSR, 2003-04-01
 309
 310   ;; We do this solely for the -OR-GIVE-UP side effect, since we want
 311   ;; to know that the type can be figured out in the end before we
 312   ;; proceed, but we don't care yet what the type will turn out to be.
 313   (upgraded-element-type-specifier-or-give-up %array)
 314
 315   '(if (array-header-p %array)
 316        (values (%array-data-vector %array) %index)
 317        (values %array %index)))
 318 \f
 319 ;;;; BIT-VECTOR hackery
 320
 321 ;;; SIMPLE-BIT-VECTOR bit-array operations are transformed to a word
 322 ;;; loop that does 32 bits at a time.
 323 ;;;
 324 ;;; FIXME: This is a lot of repeatedly macroexpanded code. It should
 325 ;;; be a function call instead.
 326 (macrolet ((def (bitfun wordfun)
 327              `(deftransform ,bitfun ((bit-array-1 bit-array-2 result-bit-array)
 328                                      (simple-bit-vector
 329                                       simple-bit-vector
 330                                       simple-bit-vector)
 331                                      *
 332                                      :node node :policy (>= speed space))
 333                 `(progn
 334                    ,@(unless (policy node (zerop safety))
 335                              '((unless (= (length bit-array-1)
 336                                           (length bit-array-2)
 337                                           (length result-bit-array))
 338                                  (error "Argument and/or result bit arrays are not the same length:~
 339                          ~%  ~S~%  ~S  ~%  ~S"
 340                                         bit-array-1
 341                                         bit-array-2
 342                                         result-bit-array))))
 343                   (let ((length (length result-bit-array)))
 344                     (if (= length 0)
 345                         ;; We avoid doing anything to 0-length
 346                         ;; bit-vectors, or rather, the memory that
 347                         ;; follows them. Other divisible-by-32 cases
 348                         ;; are handled by the (1- length), below.
 349                         ;; CSR, 2002-04-24
 350                         result-bit-array
 351                         (do ((index 0 (1+ index))
 352                              ;; bit-vectors of length 1-32 need
 353                              ;; precisely one (SETF %VECTOR-RAW-BITS),
 354                              ;; done here in the epilogue. - CSR,
 355                              ;; 2002-04-24
 356                              (end-1 (truncate (truly-the index (1- length))
 357                                               sb!vm:n-word-bits)))
 358                             ((>= index end-1)
 359                              (setf (%vector-raw-bits result-bit-array index)
 360                                    (,',wordfun (%vector-raw-bits bit-array-1 index)
 361                                                (%vector-raw-bits bit-array-2 index)))
 362                              result-bit-array)
 363                           (declare (optimize (speed 3) (safety 0))
 364                                    (type index index end-1))
 365                           (setf (%vector-raw-bits result-bit-array index)
 366                                 (,',wordfun (%vector-raw-bits bit-array-1 index)
 367                                             (%vector-raw-bits bit-array-2 index))))))))))
 368  (def bit-and word-logical-and)
 369  (def bit-ior word-logical-or)
 370  (def bit-xor word-logical-xor)
 371  (def bit-eqv word-logical-eqv)
 372  (def bit-nand word-logical-nand)
 373  (def bit-nor word-logical-nor)
 374  (def bit-andc1 word-logical-andc1)
 375  (def bit-andc2 word-logical-andc2)
 376  (def bit-orc1 word-logical-orc1)
 377  (def bit-orc2 word-logical-orc2))
 378
 379 (deftransform bit-not
 380               ((bit-array result-bit-array)
 381                (simple-bit-vector simple-bit-vector) *
 382                :node node :policy (>= speed space))
 383   `(progn
 384      ,@(unless (policy node (zerop safety))
 385          '((unless (= (length bit-array)
 386                       (length result-bit-array))
 387              (error "Argument and result bit arrays are not the same length:~
 388                      ~%  ~S~%  ~S"
 389                     bit-array result-bit-array))))
 390     (let ((length (length result-bit-array)))
 391       (if (= length 0)
 392           ;; We avoid doing anything to 0-length bit-vectors, or rather,
 393           ;; the memory that follows them. Other divisible-by
 394           ;; n-word-bits cases are handled by the (1- length), below.
 395           ;; CSR, 2002-04-24
 396           result-bit-array
 397           (do ((index 0 (1+ index))
 398                ;; bit-vectors of length 1 to n-word-bits need precisely
 399                ;; one (SETF %VECTOR-RAW-BITS), done here in the
 400                ;; epilogue. - CSR, 2002-04-24
 401                (end-1 (truncate (truly-the index (1- length))
 402                                 sb!vm:n-word-bits)))
 403               ((>= index end-1)
 404                (setf (%vector-raw-bits result-bit-array index)
 405                      (word-logical-not (%vector-raw-bits bit-array index)))
 406                result-bit-array)
 407             (declare (optimize (speed 3) (safety 0))
 408                      (type index index end-1))
 409             (setf (%vector-raw-bits result-bit-array index)
 410                   (word-logical-not (%vector-raw-bits bit-array index))))))))
 411
 412 (deftransform bit-vector-= ((x y) (simple-bit-vector simple-bit-vector))
 413   `(and (= (length x) (length y))
 414         (let ((length (length x)))
 415           (or (= length 0)
 416               (do* ((i 0 (+ i 1))
 417                     (end-1 (floor (1- length) sb!vm:n-word-bits)))
 418                    ((>= i end-1)
 419                     (let* ((extra (1+ (mod (1- length) sb!vm:n-word-bits)))
 420                            (mask (ash #.(1- (ash 1 sb!vm:n-word-bits))
 421                                       (- extra sb!vm:n-word-bits)))
 422                            (numx
 423                             (logand
 424                              (ash mask
 425                                   ,(ecase sb!c:*backend-byte-order*
 426                                      (:little-endian 0)
 427                                      (:big-endian
 428                                       '(- sb!vm:n-word-bits extra))))
 429                              (%vector-raw-bits x i)))
 430                            (numy
 431                             (logand
 432                              (ash mask
 433                                   ,(ecase sb!c:*backend-byte-order*
 434                                      (:little-endian 0)
 435                                      (:big-endian
 436                                       '(- sb!vm:n-word-bits extra))))
 437                              (%vector-raw-bits y i))))
 438                       (declare (type (integer 1 #.sb!vm:n-word-bits) extra)
 439                                (type sb!vm:word mask numx numy))
 440                       (= numx numy)))
 441                 (declare (type index i end-1))
 442                 (let ((numx (%vector-raw-bits x i))
 443                       (numy (%vector-raw-bits y i)))
 444                   (declare (type sb!vm:word numx numy))
 445                   (unless (= numx numy)
 446                     (return nil))))))))
 447
 448 (deftransform count ((item sequence) (bit simple-bit-vector) *
 449                      :policy (>= speed space))
 450   `(let ((length (length sequence)))
 451     (if (zerop length)
 452         0
 453         (do ((index 0 (1+ index))
 454              (count 0)
 455              (end-1 (truncate (truly-the index (1- length))
 456                               sb!vm:n-word-bits)))
 457             ((>= index end-1)
 458              (let* ((extra (1+ (mod (1- length) sb!vm:n-word-bits)))
 459                     (mask (ash #.(1- (ash 1 sb!vm:n-word-bits))
 460                                (- extra sb!vm:n-word-bits)))
 461                     (bits (logand (ash mask
 462                                        ,(ecase sb!c:*backend-byte-order*
 463                                                (:little-endian 0)
 464                                                (:big-endian
 465                                                 '(- sb!vm:n-word-bits extra))))
 466                                   (%vector-raw-bits sequence index))))
 467                (declare (type (integer 1 #.sb!vm:n-word-bits) extra))
 468                (declare (type sb!vm:word mask bits))
 469                (incf count (logcount bits))
 470                ,(if (constant-lvar-p item)
 471                     (if (zerop (lvar-value item))
 472                         '(- length count)
 473                         'count)
 474                     '(if (zerop item)
 475                          (- length count)
 476                          count))))
 477           (declare (type index index count end-1)
 478                    (optimize (speed 3) (safety 0)))
 479           (incf count (logcount (%vector-raw-bits sequence index)))))))
 480
 481 (deftransform fill ((sequence item) (simple-bit-vector bit) *
 482                     :policy (>= speed space))
 483   (let ((value (if (constant-lvar-p item)
 484                    (if (= (lvar-value item) 0)
 485                        0
 486                        #.(1- (ash 1 sb!vm:n-word-bits)))
 487                    `(if (= item 0) 0 #.(1- (ash 1 sb!vm:n-word-bits))))))
 488     `(let ((length (length sequence))
 489            (value ,value))
 490        (if (= length 0)
 491            sequence
 492            (do ((index 0 (1+ index))
 493                 ;; bit-vectors of length 1 to n-word-bits need precisely
 494                 ;; one (SETF %VECTOR-RAW-BITS), done here in the
 495                 ;; epilogue. - CSR, 2002-04-24
 496                 (end-1 (truncate (truly-the index (1- length))
 497                                  sb!vm:n-word-bits)))
 498                ((>= index end-1)
 499                 (setf (%vector-raw-bits sequence index) value)
 500                 sequence)
 501              (declare (optimize (speed 3) (safety 0))
 502                       (type index index end-1))
 503              (setf (%vector-raw-bits sequence index) value))))))
 504
 505 (deftransform fill ((sequence item) (simple-base-string base-char) *
 506                     :policy (>= speed space))
 507   (let ((value (if (constant-lvar-p item)
 508                    (let* ((char (lvar-value item))
 509                           (code (sb!xc:char-code char))
 510                           (accum 0))
 511                      (dotimes (i sb!vm:n-word-bytes accum)
 512                        (setf accum (logior accum (ash code (* 8 i))))))
 513                    `(let ((code (sb!xc:char-code item)))
 514                      (logior ,@(loop for i from 0 below sb!vm:n-word-bytes
 515                                      collect `(ash code ,(* 8 i))))))))
 516     `(let ((length (length sequence))
 517            (value ,value))
 518       (multiple-value-bind (times rem)
 519           (truncate length sb!vm:n-word-bytes)
 520         (do ((index 0 (1+ index))
 521              (end times))
 522             ((>= index end)
 523              (let ((place (* times sb!vm:n-word-bytes)))
 524                (declare (fixnum place))
 525                (dotimes (j rem sequence)
 526                  (declare (index j))
 527                  (setf (schar sequence (the index (+ place j))) item))))
 528           (declare (optimize (speed 3) (safety 0))
 529                    (type index index))
 530           (setf (%vector-raw-bits sequence index) value))))))
 531 \f
 532 ;;;; %BYTE-BLT
 533
 534 ;;; FIXME: The old CMU CL code used various COPY-TO/FROM-SYSTEM-AREA
 535 ;;; stuff (with all the associated bit-index cruft and overflow
 536 ;;; issues) even for byte moves. In SBCL, we're converting to byte
 537 ;;; moves as problems are discovered with the old code, and this is
 538 ;;; currently (ca. sbcl-0.6.12.30) the main interface for code in
 539 ;;; SB!KERNEL and SB!SYS (e.g. i/o code). It's not clear that it's the
 540 ;;; ideal interface, though, and it probably deserves some thought.
 541 (deftransform %byte-blt ((src src-start dst dst-start dst-end)
 542                          ((or (simple-unboxed-array (*)) system-area-pointer)
 543                           index
 544                           (or (simple-unboxed-array (*)) system-area-pointer)
 545                           index
 546                           index))
 547   ;; FIXME: CMU CL had a hairier implementation of this (back when it
 548   ;; was still called (%PRIMITIVE BYTE-BLT). It had the small problem
 549   ;; that it didn't work for large (>16M) values of SRC-START or
 550   ;; DST-START. However, it might have been more efficient. In
 551   ;; particular, I don't really know how much the foreign function
 552   ;; call costs us here. My guess is that if the overhead is
 553   ;; acceptable for SQRT and COS, it's acceptable here, but this
 554   ;; should probably be checked. -- WHN
 555   '(flet ((sapify (thing)
 556             (etypecase thing
 557               (system-area-pointer thing)
 558               ;; FIXME: The code here rather relies on the simple
 559               ;; unboxed array here having byte-sized entries. That
 560               ;; should be asserted explicitly, I just haven't found
 561               ;; a concise way of doing it. (It would be nice to
 562               ;; declare it in the DEFKNOWN too.)
 563               ((simple-unboxed-array (*)) (vector-sap thing)))))
 564      (declare (inline sapify))
 565     (with-pinned-objects (dst src)
 566       (memmove (sap+ (sapify dst) dst-start)
 567                (sap+ (sapify src) src-start)
 568                (- dst-end dst-start)))
 569      (values)))
 570 \f
 571 ;;;; transforms for EQL of floating point values
 572 #!-float-eql-vops
 573 (deftransform eql ((x y) (single-float single-float))
 574   '(= (single-float-bits x) (single-float-bits y)))
 575
 576 #!-float-eql-vops
 577 (deftransform eql ((x y) (double-float double-float))
 578   '(and (= (double-float-low-bits x) (double-float-low-bits y))
 579         (= (double-float-high-bits x) (double-float-high-bits y))))
 580
 581 \f
 582 ;;;; modular functions
 583 ;;;
 584 ;;; FIXME: I think that the :GOODness of a modular function boils down
 585 ;;; to whether the normal definition can be used in the middle of a
 586 ;;; modular arrangement.  LOGAND and LOGIOR can be for all unsigned
 587 ;;; modular implementations, I believe, because for all unsigned
 588 ;;; arguments of a given size the result of the ordinary definition is
 589 ;;; the right one.  This should follow through to other logical
 590 ;;; functions, such as LOGXOR, should it not?  -- CSR, 2007-12-29,
 591 ;;; trying to understand a comment he wrote over four years
 592 ;;; previously: "FIXME: XOR? ANDC1, ANDC2?  -- CSR, 2003-09-16"
 593 (define-good-modular-fun logand :untagged nil)
 594 (define-good-modular-fun logior :untagged nil)
 595 (define-good-modular-fun logxor :untagged nil)
 596 (macrolet ((define-good-signed-modular-funs (&rest funs)
 597              (let (result)
 598                `(progn
 599                  ,@(dolist (fun funs (nreverse result))
 600                      (push `(define-good-modular-fun ,fun :untagged t) result)
 601                      (push `(define-good-modular-fun ,fun :tagged t) result))))))
 602   (define-good-signed-modular-funs
 603       logand logandc1 logandc2 logeqv logior lognand lognor lognot
 604       logorc1 logorc2 logxor))
 605
 606 (macrolet
 607     ((def (name kind width signedp)
 608        (let ((type (ecase signedp
 609                      ((nil) 'unsigned-byte)
 610                      ((t) 'signed-byte))))
 611          `(progn
 612             (defknown ,name (integer (integer 0)) (,type ,width)
 613                       (foldable flushable movable))
 614             (define-modular-fun-optimizer ash ((integer count) ,kind ,signedp :width width)
 615               (when (and (<= width ,width)
 616                          (or (and (constant-lvar-p count)
 617                                   (plusp (lvar-value count)))
 618                              (csubtypep (lvar-type count)
 619                                         (specifier-type '(and unsigned-byte fixnum)))))
 620                 (cut-to-width integer ,kind width ,signedp)
 621                 ',name))
 622             (setf (gethash ',name (modular-class-versions (find-modular-class ',kind ',signedp)))
 623                   `(ash ,',width))))))
 624   ;; This should really be dependent on SB!VM:N-WORD-BITS, but since we
 625   ;; don't have a true Alpha64 port yet, we'll have to stick to
 626   ;; SB!VM:N-MACHINE-WORD-BITS for the time being.  --njf, 2004-08-14
 627   #!+#.(cl:if (cl:= 32 sb!vm:n-machine-word-bits) '(and) '(or))
 628   (progn
 629     #!+x86 (def sb!vm::ash-left-smod30 :tagged 30 t)
 630     (def sb!vm::ash-left-mod32 :untagged 32 nil))
 631   #!+#.(cl:if (cl:= 64 sb!vm:n-machine-word-bits) '(and) '(or))
 632   (progn
 633     #!+x86-64 (def sb!vm::ash-left-smod61 :tagged 61 t)
 634     (def sb!vm::ash-left-mod64 :untagged 64 nil)))
 635 \f
 636 ;;;; word-wise logical operations
 637
 638 ;;; These transforms assume the presence of modular arithmetic to
 639 ;;; generate efficient code.
 640
 641 (define-source-transform word-logical-not (x)
 642   `(logand (lognot (the sb!vm:word ,x)) #.(1- (ash 1 sb!vm:n-word-bits))))
 643
 644 (deftransform word-logical-and ((x y))
 645   '(logand x y))
 646
 647 (deftransform word-logical-nand ((x y))
 648   '(logand (lognand x y) #.(1- (ash 1 sb!vm:n-word-bits))))
 649
 650 (deftransform word-logical-or ((x y))
 651   '(logior x y))
 652
 653 (deftransform word-logical-nor ((x y))
 654   '(logand (lognor x y) #.(1- (ash 1 sb!vm:n-word-bits))))
 655
 656 (deftransform word-logical-xor ((x y))
 657   '(logxor x y))
 658
 659 (deftransform word-logical-eqv ((x y))
 660   '(logand (logeqv x y) #.(1- (ash 1 sb!vm:n-word-bits))))
 661
 662 (deftransform word-logical-orc1 ((x y))
 663   '(logand (logorc1 x y) #.(1- (ash 1 sb!vm:n-word-bits))))
 664
 665 (deftransform word-logical-orc2 ((x y))
 666   '(logand (logorc2 x y) #.(1- (ash 1 sb!vm:n-word-bits))))
 667
 668 (deftransform word-logical-andc1 ((x y))
 669   '(logand (logandc1 x y) #.(1- (ash 1 sb!vm:n-word-bits))))
 670
 671 (deftransform word-logical-andc2 ((x y))
 672   '(logand (logandc2 x y) #.(1- (ash 1 sb!vm:n-word-bits))))
 673
 674 \f
 675 ;;; There are two different ways the multiplier can be recoded. The
 676 ;;; more obvious is to shift X by the correct amount for each bit set
 677 ;;; in Y and to sum the results. But if there is a string of bits that
 678 ;;; are all set, you can add X shifted by one more then the bit
 679 ;;; position of the first set bit and subtract X shifted by the bit
 680 ;;; position of the last set bit. We can't use this second method when
 681 ;;; the high order bit is bit 31 because shifting by 32 doesn't work
 682 ;;; too well.
 683 (defun ub32-strength-reduce-constant-multiply (arg num)
 684   (declare (type (unsigned-byte 32) num))
 685   (let ((adds 0) (shifts 0)
 686         (result nil) first-one)
 687     (labels ((add (next-factor)
 688                (setf result
 689                      (if result
 690                          (progn (incf adds) `(+ ,result ,next-factor))
 691                          next-factor))))
 692       (declare (inline add))
 693       (dotimes (bitpos 32)
 694         (if first-one
 695             (when (not (logbitp bitpos num))
 696               (add (if (= (1+ first-one) bitpos)
 697                        ;; There is only a single bit in the string.
 698                        (progn (incf shifts) `(ash ,arg ,first-one))
 699                        ;; There are at least two.
 700                        (progn
 701                          (incf adds)
 702                          (incf shifts 2)
 703                          `(- (ash ,arg ,bitpos)
 704                              (ash ,arg ,first-one)))))
 705               (setf first-one nil))
 706             (when (logbitp bitpos num)
 707               (setf first-one bitpos))))
 708       (when first-one
 709         (cond ((= first-one 31))
 710               ((= first-one 30) (incf shifts) (add `(ash ,arg 30)))
 711               (t
 712                (incf shifts 2)
 713                (incf adds)
 714                (add `(- (ash ,arg 31)
 715                         (ash ,arg ,first-one)))))
 716         (incf shifts)
 717         (add `(ash ,arg 31))))
 718     (values (if (plusp adds)
 719                 `(logand ,result #.(1- (ash 1 32))) ; using modular arithmetic
 720                 result)
 721             adds
 722             shifts)))
 723
 724 \f
 725 ;;; Transform GET-LISP-OBJ-ADDRESS for constant immediates, since the normal
 726 ;;; VOP can't handle them.
 727
 728 (deftransform sb!vm::get-lisp-obj-address ((obj) ((constant-arg fixnum)))
 729   (ash (lvar-value obj) sb!vm::n-fixnum-tag-bits))
 730
 731 (deftransform sb!vm::get-lisp-obj-address ((obj) ((constant-arg character)))
 732   (logior sb!vm::character-widetag
 733           (ash (char-code (lvar-value obj)) sb!vm::n-widetag-bits)))