1 ;;;; This file implements the IR1 optimization phase of the compiler.
2 ;;;; IR1 optimization is a grab-bag of optimizations that don't make
3 ;;;; major changes to the block-level control flow and don't use flow
4 ;;;; analysis. These optimizations can mostly be classified as
5 ;;;; "meta-evaluation", but there is a sizable top-down component as
8 ;;;; This software is part of the SBCL system. See the README file for
11 ;;;; This software is derived from the CMU CL system, which was
12 ;;;; written at Carnegie Mellon University and released into the
13 ;;;; public domain. The software is in the public domain and is
14 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
15 ;;;; files for more information.
19 ;;;; interface for obtaining results of constant folding
21 ;;; Return true for an LVAR whose sole use is a reference to a
23 (defun constant-lvar-p (thing)
24 (declare (type (or lvar null) thing))
26 (let ((use (principal-lvar-use thing)))
27 (and (ref-p use) (constant-p (ref-leaf use))))))
29 ;;; Return the constant value for an LVAR whose only use is a constant
31 (declaim (ftype (function (lvar) t) lvar-value))
32 (defun lvar-value (lvar)
33 (let ((use (principal-lvar-use lvar)))
34 (constant-value (ref-leaf use))))
36 ;;;; interface for obtaining results of type inference
38 ;;; Our best guess for the type of this lvar's value. Note that this
39 ;;; may be VALUES or FUNCTION type, which cannot be passed as an
40 ;;; argument to the normal type operations. See LVAR-TYPE.
42 ;;; The result value is cached in the LVAR-%DERIVED-TYPE slot. If the
43 ;;; slot is true, just return that value, otherwise recompute and
44 ;;; stash the value there.
45 (eval-when (:compile-toplevel :execute)
46 (#+sb-xc-host cl:defmacro
47 #-sb-xc-host sb!xc:defmacro
48 lvar-type-using (lvar accessor)
49 `(let ((uses (lvar-uses ,lvar)))
50 (cond ((null uses) *empty-type*)
52 (do ((res (,accessor (first uses))
53 (values-type-union (,accessor (first current))
55 (current (rest uses) (rest current)))
56 ((or (null current) (eq res *wild-type*))
61 #!-sb-fluid (declaim (inline lvar-derived-type))
62 (defun lvar-derived-type (lvar)
63 (declare (type lvar lvar))
64 (or (lvar-%derived-type lvar)
65 (setf (lvar-%derived-type lvar)
66 (%lvar-derived-type lvar))))
67 (defun %lvar-derived-type (lvar)
68 (lvar-type-using lvar node-derived-type))
70 ;;; Return the derived type for LVAR's first value. This is guaranteed
71 ;;; not to be a VALUES or FUNCTION type.
72 (declaim (ftype (sfunction (lvar) ctype) lvar-type))
73 (defun lvar-type (lvar)
74 (single-value-type (lvar-derived-type lvar)))
76 ;;; LVAR-CONSERVATIVE-TYPE
78 ;;; Certain types refer to the contents of an object, which can
79 ;;; change without type derivation noticing: CONS types and ARRAY
80 ;;; types suffer from this:
82 ;;; (let ((x (the (cons fixnum fixnum) (cons a b))))
84 ;;; (+ (car x) (cdr x)))
86 ;;; Python doesn't realize that the SETF CAR can change the type of X -- so we
87 ;;; cannot use LVAR-TYPE which gets the derived results. Worse, still, instead
88 ;;; of (SETF CAR) we might have a call to a user-defined function FOO which
89 ;;; does the same -- so there is no way to use the derived information in
92 ;;; So, the conservative option is to use the derived type if the leaf has
93 ;;; only a single ref -- in which case there cannot be a prior call that
94 ;;; mutates it. Otherwise we use the declared type or punt to the most general
95 ;;; type we know to be correct for sure.
96 (defun lvar-conservative-type (lvar)
97 (let ((derived-type (lvar-type lvar))
98 (t-type *universal-type*))
99 ;; Recompute using NODE-CONSERVATIVE-TYPE instead of derived type if
100 ;; necessary -- picking off some easy cases up front.
101 (cond ((or (eq derived-type t-type)
102 ;; Can't use CSUBTYPEP!
103 (type= derived-type (specifier-type 'list))
104 (type= derived-type (specifier-type 'null)))
106 ((and (cons-type-p derived-type)
107 (eq t-type (cons-type-car-type derived-type))
108 (eq t-type (cons-type-cdr-type derived-type)))
110 ((and (array-type-p derived-type)
111 (or (not (array-type-complexp derived-type))
112 (let ((dimensions (array-type-dimensions derived-type)))
113 (or (eq '* dimensions)
114 (every (lambda (dim) (eq '* dim)) dimensions)))))
116 ((type-needs-conservation-p derived-type)
117 (single-value-type (lvar-type-using lvar node-conservative-type)))
121 (defun node-conservative-type (node)
122 (let* ((derived-values-type (node-derived-type node))
123 (derived-type (single-value-type derived-values-type)))
125 (let ((leaf (ref-leaf node)))
126 (if (and (basic-var-p leaf)
127 (cdr (leaf-refs leaf)))
129 (if (eq :declared (leaf-where-from leaf))
131 (conservative-type derived-type)))
132 derived-values-type))
133 derived-values-type)))
135 (defun conservative-type (type)
136 (cond ((or (eq type *universal-type*)
137 (eq type (specifier-type 'list))
138 (eq type (specifier-type 'null)))
141 (specifier-type 'cons))
143 (if (array-type-complexp type)
145 ;; ADJUST-ARRAY may change dimensions, but rank stays same.
147 (let ((old (array-type-dimensions type)))
150 (mapcar (constantly '*) old)))
151 ;; Complexity cannot change.
152 :complexp (array-type-complexp type)
153 ;; Element type cannot change.
154 :element-type (array-type-element-type type)
155 :specialized-element-type (array-type-specialized-element-type type))
156 ;; Simple arrays cannot change at all.
159 ;; If the type contains some CONS types, the conservative type contains all
161 (when (types-equal-or-intersect type (specifier-type 'cons))
162 (setf type (type-union type (specifier-type 'cons))))
163 ;; Similarly for non-simple arrays -- it should be possible to preserve
164 ;; more information here, but really...
165 (let ((non-simple-arrays (specifier-type '(and array (not simple-array)))))
166 (when (types-equal-or-intersect type non-simple-arrays)
167 (setf type (type-union type non-simple-arrays))))
170 (defun type-needs-conservation-p (type)
171 (cond ((eq type *universal-type*)
172 ;; Excluding T is necessary, because we do want type derivation to
173 ;; be able to narrow it down in case someone (most like a macro-expansion...)
174 ;; actually declares something as having type T.
176 ((or (cons-type-p type) (and (array-type-p type) (array-type-complexp type)))
177 ;; Covered by the next case as well, but this is a quick test.
179 ((types-equal-or-intersect type (specifier-type '(or cons (and array (not simple-array)))))
182 ;;; If LVAR is an argument of a function, return a type which the
183 ;;; function checks LVAR for.
184 #!-sb-fluid (declaim (inline lvar-externally-checkable-type))
185 (defun lvar-externally-checkable-type (lvar)
186 (or (lvar-%externally-checkable-type lvar)
187 (%lvar-%externally-checkable-type lvar)))
188 (defun %lvar-%externally-checkable-type (lvar)
189 (declare (type lvar lvar))
190 (let ((dest (lvar-dest lvar)))
191 (if (not (and dest (combination-p dest)))
192 ;; TODO: MV-COMBINATION
193 (setf (lvar-%externally-checkable-type lvar) *wild-type*)
194 (let* ((fun (combination-fun dest))
195 (args (combination-args dest))
196 (fun-type (lvar-type fun)))
197 (setf (lvar-%externally-checkable-type fun) *wild-type*)
198 (if (or (not (call-full-like-p dest))
199 (not (fun-type-p fun-type))
200 ;; FUN-TYPE might be (AND FUNCTION (SATISFIES ...)).
201 (fun-type-wild-args fun-type))
204 (setf (lvar-%externally-checkable-type arg)
206 (map-combination-args-and-types
208 (setf (lvar-%externally-checkable-type arg)
209 (acond ((lvar-%externally-checkable-type arg)
210 (values-type-intersection
211 it (coerce-to-values type)))
212 (t (coerce-to-values type)))))
214 (lvar-%externally-checkable-type lvar))
215 #!-sb-fluid(declaim (inline flush-lvar-externally-checkable-type))
216 (defun flush-lvar-externally-checkable-type (lvar)
217 (declare (type lvar lvar))
218 (setf (lvar-%externally-checkable-type lvar) nil))
220 ;;;; interface routines used by optimizers
222 (declaim (inline reoptimize-component))
223 (defun reoptimize-component (component kind)
224 (declare (type component component)
225 (type (member nil :maybe t) kind))
227 (unless (eq (component-reoptimize component) t)
228 (setf (component-reoptimize component) kind)))
230 ;;; This function is called by optimizers to indicate that something
231 ;;; interesting has happened to the value of LVAR. Optimizers must
232 ;;; make sure that they don't call for reoptimization when nothing has
233 ;;; happened, since optimization will fail to terminate.
235 ;;; We clear any cached type for the lvar and set the reoptimize flags
236 ;;; on everything in sight.
237 (defun reoptimize-lvar (lvar)
238 (declare (type (or lvar null) lvar))
240 (setf (lvar-%derived-type lvar) nil)
241 (let ((dest (lvar-dest lvar)))
243 (setf (lvar-reoptimize lvar) t)
244 (setf (node-reoptimize dest) t)
245 (binding* (;; Since this may be called during IR1 conversion,
246 ;; PREV may be missing.
247 (prev (node-prev dest) :exit-if-null)
248 (block (ctran-block prev))
249 (component (block-component block)))
250 (when (typep dest 'cif)
251 (setf (block-test-modified block) t))
252 (setf (block-reoptimize block) t)
253 (reoptimize-component component :maybe))))
255 (setf (block-type-check (node-block node)) t)))
258 (defun reoptimize-lvar-uses (lvar)
259 (declare (type lvar lvar))
261 (setf (node-reoptimize use) t)
262 (setf (block-reoptimize (node-block use)) t)
263 (reoptimize-component (node-component use) :maybe)))
265 ;;; Annotate NODE to indicate that its result has been proven to be
266 ;;; TYPEP to RTYPE. After IR1 conversion has happened, this is the
267 ;;; only correct way to supply information discovered about a node's
268 ;;; type. If you screw with the NODE-DERIVED-TYPE directly, then
269 ;;; information may be lost and reoptimization may not happen.
271 ;;; What we do is intersect RTYPE with NODE's DERIVED-TYPE. If the
272 ;;; intersection is different from the old type, then we do a
273 ;;; REOPTIMIZE-LVAR on the NODE-LVAR.
274 (defun derive-node-type (node rtype)
275 (declare (type valued-node node) (type ctype rtype))
276 (let ((node-type (node-derived-type node)))
277 (unless (eq node-type rtype)
278 (let ((int (values-type-intersection node-type rtype))
279 (lvar (node-lvar node)))
280 (when (type/= node-type int)
281 (when (and *check-consistency*
282 (eq int *empty-type*)
283 (not (eq rtype *empty-type*)))
284 (let ((*compiler-error-context* node))
286 "New inferred type ~S conflicts with old type:~
287 ~% ~S~%*** possible internal error? Please report this."
288 (type-specifier rtype) (type-specifier node-type))))
289 (setf (node-derived-type node) int)
290 ;; If the new type consists of only one object, replace the
291 ;; node with a constant reference.
292 (when (and (ref-p node)
293 (lambda-var-p (ref-leaf node)))
294 (let ((type (single-value-type int)))
295 (when (and (member-type-p type)
296 (eql 1 (member-type-size type)))
297 (change-ref-leaf node (find-constant
298 (first (member-type-members type)))))))
299 (reoptimize-lvar lvar)))))
302 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
303 ;;; error for LVAR's value not to be TYPEP to TYPE. We implement it
304 ;;; splitting off DEST a new CAST node; old LVAR will deliver values
305 ;;; to CAST. If we improve the assertion, we set TYPE-CHECK and
306 ;;; TYPE-ASSERTED to guarantee that the new assertion will be checked.
307 (defun assert-lvar-type (lvar type policy)
308 (declare (type lvar lvar) (type ctype type))
309 (unless (values-subtypep (lvar-derived-type lvar) type)
310 (let ((internal-lvar (make-lvar))
311 (dest (lvar-dest lvar)))
312 (substitute-lvar internal-lvar lvar)
313 (let ((cast (insert-cast-before dest lvar type policy)))
314 (use-lvar cast internal-lvar))))
320 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
321 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
322 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
323 ;;; we are done, then another iteration would be beneficial.
324 (defun ir1-optimize (component fastp)
325 (declare (type component component))
326 (setf (component-reoptimize component) nil)
327 (loop with block = (block-next (component-head component))
328 with tail = (component-tail component)
329 for last-block = block
330 until (eq block tail)
332 ;; We delete blocks when there is either no predecessor or the
333 ;; block is in a lambda that has been deleted. These blocks
334 ;; would eventually be deleted by DFO recomputation, but doing
335 ;; it here immediately makes the effect available to IR1
337 ((or (block-delete-p block)
338 (null (block-pred block)))
339 (delete-block-lazily block)
340 (setq block (clean-component component block)))
341 ((eq (functional-kind (block-home-lambda block)) :deleted)
342 ;; Preserve the BLOCK-SUCC invariant that almost every block has
343 ;; one successor (and a block with DELETE-P set is an acceptable
345 (mark-for-deletion block)
346 (setq block (clean-component component block)))
349 (let ((succ (block-succ block)))
350 (unless (singleton-p succ)
353 (let ((last (block-last block)))
356 (flush-dest (if-test last))
357 (when (unlink-node last)
360 (when (maybe-delete-exit last)
363 (unless (join-successor-if-possible block)
366 (when (and (not fastp) (block-reoptimize block) (block-component block))
367 (aver (not (block-delete-p block)))
368 (ir1-optimize-block block))
370 (cond ((and (block-delete-p block) (block-component block))
371 (setq block (clean-component component block)))
372 ((and (block-flush-p block) (block-component block))
373 (flush-dead-code block)))))
374 do (when (eq block last-block)
375 (setq block (block-next block))))
379 ;;; Loop over the nodes in BLOCK, acting on (and clearing) REOPTIMIZE
382 ;;; Note that although they are cleared here, REOPTIMIZE flags might
383 ;;; still be set upon return from this function, meaning that further
384 ;;; optimization is wanted (as a consequence of optimizations we did).
385 (defun ir1-optimize-block (block)
386 (declare (type cblock block))
387 ;; We clear the node and block REOPTIMIZE flags before doing the
388 ;; optimization, not after. This ensures that the node or block will
389 ;; be reoptimized if necessary.
390 (setf (block-reoptimize block) nil)
391 (do-nodes (node nil block :restart-p t)
392 (when (node-reoptimize node)
393 ;; As above, we clear the node REOPTIMIZE flag before optimizing.
394 (setf (node-reoptimize node) nil)
398 ;; With a COMBINATION, we call PROPAGATE-FUN-CHANGE whenever
399 ;; the function changes, and call IR1-OPTIMIZE-COMBINATION if
400 ;; any argument changes.
401 (ir1-optimize-combination node))
403 (ir1-optimize-if node))
405 ;; KLUDGE: We leave the NODE-OPTIMIZE flag set going into
406 ;; IR1-OPTIMIZE-RETURN, since IR1-OPTIMIZE-RETURN wants to
407 ;; clear the flag itself. -- WHN 2002-02-02, quoting original
409 (setf (node-reoptimize node) t)
410 (ir1-optimize-return node))
412 (ir1-optimize-mv-combination node))
414 ;; With an EXIT, we derive the node's type from the VALUE's
416 (let ((value (exit-value node)))
418 (derive-node-type node (lvar-derived-type value)))))
420 ;; PROPAGATE-FROM-SETS can do a better job if NODE-REOPTIMIZE
421 ;; is accurate till the node actually has been reoptimized.
422 (setf (node-reoptimize node) t)
423 (ir1-optimize-set node))
425 (ir1-optimize-cast node)))))
429 ;;; Try to join with a successor block. If we succeed, we return true,
431 (defun join-successor-if-possible (block)
432 (declare (type cblock block))
433 (let ((next (first (block-succ block))))
434 (when (block-start next) ; NEXT is not an END-OF-COMPONENT marker
435 (cond ( ;; We cannot combine with a successor block if:
437 ;; the successor has more than one predecessor;
438 (rest (block-pred next))
439 ;; the successor is the current block (infinite loop);
441 ;; the next block has a different cleanup, and thus
442 ;; we may want to insert cleanup code between the
443 ;; two blocks at some point;
444 (not (eq (block-end-cleanup block)
445 (block-start-cleanup next)))
446 ;; the next block has a different home lambda, and
447 ;; thus the control transfer is a non-local exit.
448 (not (eq (block-home-lambda block)
449 (block-home-lambda next)))
450 ;; Stack analysis phase wants ENTRY to start a block...
451 (entry-p (block-start-node next))
452 (let ((last (block-last block)))
453 (and (valued-node-p last)
454 (awhen (node-lvar last)
456 ;; ... and a DX-allocator to end a block.
457 (lvar-dynamic-extent it)
458 ;; FIXME: This is a partial workaround for bug 303.
459 (consp (lvar-uses it)))))))
462 (join-blocks block next)
465 ;;; Join together two blocks. The code in BLOCK2 is moved into BLOCK1
466 ;;; and BLOCK2 is deleted from the DFO. We combine the optimize flags
467 ;;; for the two blocks so that any indicated optimization gets done.
468 (defun join-blocks (block1 block2)
469 (declare (type cblock block1 block2))
470 (let* ((last1 (block-last block1))
471 (last2 (block-last block2))
472 (succ (block-succ block2))
473 (start2 (block-start block2)))
474 (do ((ctran start2 (node-next (ctran-next ctran))))
476 (setf (ctran-block ctran) block1))
478 (unlink-blocks block1 block2)
480 (unlink-blocks block2 block)
481 (link-blocks block1 block))
483 (setf (ctran-kind start2) :inside-block)
484 (setf (node-next last1) start2)
485 (setf (ctran-use start2) last1)
486 (setf (block-last block1) last2))
488 (setf (block-flags block1)
489 (attributes-union (block-flags block1)
491 (block-attributes type-asserted test-modified)))
493 (let ((next (block-next block2))
494 (prev (block-prev block2)))
495 (setf (block-next prev) next)
496 (setf (block-prev next) prev))
500 ;;; Delete any nodes in BLOCK whose value is unused and which have no
501 ;;; side effects. We can delete sets of lexical variables when the set
502 ;;; variable has no references.
503 (defun flush-dead-code (block)
504 (declare (type cblock block))
505 (setf (block-flush-p block) nil)
506 (do-nodes-backwards (node lvar block :restart-p t)
513 (let ((kind (combination-kind node))
514 (info (combination-fun-info node)))
515 (when (and (eq kind :known) (fun-info-p info))
516 (let ((attr (fun-info-attributes info)))
517 (when (and (not (ir1-attributep attr call))
518 ;; ### For now, don't delete potentially
519 ;; flushable calls when they have the CALL
520 ;; attribute. Someday we should look at the
521 ;; functional args to determine if they have
523 (if (policy node (= safety 3))
524 (ir1-attributep attr flushable)
525 (ir1-attributep attr unsafely-flushable)))
526 (flush-combination node))))))
528 (when (eq (basic-combination-kind node) :local)
529 (let ((fun (combination-lambda node)))
530 (when (dolist (var (lambda-vars fun) t)
531 (when (or (leaf-refs var)
532 (lambda-var-sets var))
534 (flush-dest (first (basic-combination-args node)))
537 (let ((value (exit-value node)))
540 (setf (exit-value node) nil))))
542 (let ((var (set-var node)))
543 (when (and (lambda-var-p var)
544 (null (leaf-refs var)))
545 (flush-dest (set-value node))
546 (setf (basic-var-sets var)
547 (delq node (basic-var-sets var)))
548 (unlink-node node))))
550 (unless (cast-type-check node)
551 (flush-dest (cast-value node))
552 (unlink-node node))))))
556 ;;;; local call return type propagation
558 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
559 ;;; flag set. It iterates over the uses of the RESULT, looking for
560 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
561 ;;; call, then we union its type together with the types of other such
562 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
563 ;;; type with the RESULT's asserted type. We can make this
564 ;;; intersection now (potentially before type checking) because this
565 ;;; assertion on the result will eventually be checked (if
568 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
569 ;;; combination, which may change the successor of the call to be the
570 ;;; called function, and if so, checks if the call can become an
571 ;;; assignment. If we convert to an assignment, we abort, since the
572 ;;; RETURN has been deleted.
573 (defun find-result-type (node)
574 (declare (type creturn node))
575 (let ((result (return-result node)))
576 (collect ((use-union *empty-type* values-type-union))
577 (do-uses (use result)
578 (let ((use-home (node-home-lambda use)))
579 (cond ((or (eq (functional-kind use-home) :deleted)
580 (block-delete-p (node-block use))))
581 ((and (basic-combination-p use)
582 (eq (basic-combination-kind use) :local))
583 (aver (eq (lambda-tail-set use-home)
584 (lambda-tail-set (combination-lambda use))))
585 (when (combination-p use)
586 (when (nth-value 1 (maybe-convert-tail-local-call use))
587 (return-from find-result-type t))))
589 (use-union (node-derived-type use))))))
591 ;; (values-type-intersection
592 ;; (continuation-asserted-type result) ; FIXME -- APD, 2002-01-26
596 (setf (return-result-type node) int))))
599 ;;; Do stuff to realize that something has changed about the value
600 ;;; delivered to a return node. Since we consider the return values of
601 ;;; all functions in the tail set to be equivalent, this amounts to
602 ;;; bringing the entire tail set up to date. We iterate over the
603 ;;; returns for all the functions in the tail set, reanalyzing them
604 ;;; all (not treating NODE specially.)
606 ;;; When we are done, we check whether the new type is different from
607 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
608 ;;; all the lvars for references to functions in the tail set. This
609 ;;; will cause IR1-OPTIMIZE-COMBINATION to derive the new type as the
610 ;;; results of the calls.
611 (defun ir1-optimize-return (node)
612 (declare (type creturn node))
615 (let* ((tails (lambda-tail-set (return-lambda node)))
616 (funs (tail-set-funs tails)))
617 (collect ((res *empty-type* values-type-union))
619 (let ((return (lambda-return fun)))
621 (when (node-reoptimize return)
622 (setf (node-reoptimize return) nil)
623 (when (find-result-type return)
625 (res (return-result-type return)))))
627 (when (type/= (res) (tail-set-type tails))
628 (setf (tail-set-type tails) (res))
629 (dolist (fun (tail-set-funs tails))
630 (dolist (ref (leaf-refs fun))
631 (reoptimize-lvar (node-lvar ref))))))))
637 ;;; If the test has multiple uses, replicate the node when possible.
638 ;;; Also check whether the predicate is known to be true or false,
639 ;;; deleting the IF node in favor of the appropriate branch when this
641 (defun ir1-optimize-if (node)
642 (declare (type cif node))
643 (let ((test (if-test node))
644 (block (node-block node)))
646 (when (and (eq (block-start-node block) node)
647 (listp (lvar-uses test)))
649 (when (immediately-used-p test use)
650 (convert-if-if use node)
651 (when (not (listp (lvar-uses test))) (return)))))
653 (let* ((type (lvar-type test))
655 (cond ((constant-lvar-p test)
656 (if (lvar-value test)
657 (if-alternative node)
658 (if-consequent node)))
659 ((not (types-equal-or-intersect type (specifier-type 'null)))
660 (if-alternative node))
661 ((type= type (specifier-type 'null))
662 (if-consequent node)))))
665 (when (rest (block-succ block))
666 (unlink-blocks block victim))
667 (setf (component-reanalyze (node-component node)) t)
668 (unlink-node node))))
671 ;;; Create a new copy of an IF node that tests the value of the node
672 ;;; USE. The test must have >1 use, and must be immediately used by
673 ;;; USE. NODE must be the only node in its block (implying that
674 ;;; block-start = if-test).
676 ;;; This optimization has an effect semantically similar to the
677 ;;; source-to-source transformation:
678 ;;; (IF (IF A B C) D E) ==>
679 ;;; (IF A (IF B D E) (IF C D E))
681 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
682 ;;; node so that dead code deletion notes will definitely not consider
683 ;;; either node to be part of the original source. One node might
684 ;;; become unreachable, resulting in a spurious note.
685 (defun convert-if-if (use node)
686 (declare (type node use) (type cif node))
687 (with-ir1-environment-from-node node
688 (let* ((block (node-block node))
689 (test (if-test node))
690 (cblock (if-consequent node))
691 (ablock (if-alternative node))
692 (use-block (node-block use))
693 (new-ctran (make-ctran))
694 (new-lvar (make-lvar))
695 (new-node (make-if :test new-lvar
697 :alternative ablock))
698 (new-block (ctran-starts-block new-ctran)))
699 (link-node-to-previous-ctran new-node new-ctran)
700 (setf (lvar-dest new-lvar) new-node)
701 (setf (block-last new-block) new-node)
703 (unlink-blocks use-block block)
704 (%delete-lvar-use use)
705 (add-lvar-use use new-lvar)
706 (link-blocks use-block new-block)
708 (link-blocks new-block cblock)
709 (link-blocks new-block ablock)
711 (push "<IF Duplication>" (node-source-path node))
712 (push "<IF Duplication>" (node-source-path new-node))
714 (reoptimize-lvar test)
715 (reoptimize-lvar new-lvar)
716 (setf (component-reanalyze *current-component*) t)))
719 ;;;; exit IR1 optimization
721 ;;; This function attempts to delete an exit node, returning true if
722 ;;; it deletes the block as a consequence:
723 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
724 ;;; anything, since there is nothing to be done.
725 ;;; -- If the exit node and its ENTRY have the same home lambda then
726 ;;; we know the exit is local, and can delete the exit. We change
727 ;;; uses of the Exit-Value to be uses of the original lvar,
728 ;;; then unlink the node. If the exit is to a TR context, then we
729 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
730 ;;; their value to this exit.
731 ;;; -- If there is no value (as in a GO), then we skip the value
734 ;;; This function is also called by environment analysis, since it
735 ;;; wants all exits to be optimized even if normal optimization was
737 (defun maybe-delete-exit (node)
738 (declare (type exit node))
739 (let ((value (exit-value node))
740 (entry (exit-entry node)))
742 (eq (node-home-lambda node) (node-home-lambda entry)))
743 (setf (entry-exits entry) (delq node (entry-exits entry)))
745 (delete-filter node (node-lvar node) value)
746 (unlink-node node)))))
749 ;;;; combination IR1 optimization
751 ;;; Report as we try each transform?
753 (defvar *show-transforms-p* nil)
755 (defun check-important-result (node info)
756 (when (and (null (node-lvar node))
757 (ir1-attributep (fun-info-attributes info) important-result))
758 (let ((*compiler-error-context* node))
760 "The return value of ~A should not be discarded."
761 (lvar-fun-name (basic-combination-fun node))))))
763 ;;; Do IR1 optimizations on a COMBINATION node.
764 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
765 (defun ir1-optimize-combination (node)
766 (when (lvar-reoptimize (basic-combination-fun node))
767 (propagate-fun-change node)
768 (maybe-terminate-block node nil))
769 (let ((args (basic-combination-args node))
770 (kind (basic-combination-kind node))
771 (info (basic-combination-fun-info node)))
774 (let ((fun (combination-lambda node)))
775 (if (eq (functional-kind fun) :let)
776 (propagate-let-args node fun)
777 (propagate-local-call-args node fun))))
781 (setf (lvar-reoptimize arg) nil))))
785 (setf (lvar-reoptimize arg) nil)))
787 (check-important-result node info)
788 (let ((fun (fun-info-destroyed-constant-args info)))
790 (let ((destroyed-constant-args (funcall fun args)))
791 (when destroyed-constant-args
792 (let ((*compiler-error-context* node))
793 (warn 'constant-modified
794 :fun-name (lvar-fun-name
795 (basic-combination-fun node)))
796 (setf (basic-combination-kind node) :error)
797 (return-from ir1-optimize-combination))))))
798 (let ((fun (fun-info-derive-type info)))
800 (let ((res (funcall fun node)))
802 (derive-node-type node (coerce-to-values res))
803 (maybe-terminate-block node nil)))))))
808 (setf (lvar-reoptimize arg) nil)))
809 (check-important-result node info)
810 (let ((fun (fun-info-destroyed-constant-args info)))
812 ;; If somebody is really sure that they want to modify
813 ;; constants, let them.
814 (policy node (> check-constant-modification 0)))
815 (let ((destroyed-constant-args (funcall fun args)))
816 (when destroyed-constant-args
817 (let ((*compiler-error-context* node))
818 (warn 'constant-modified
819 :fun-name (lvar-fun-name
820 (basic-combination-fun node)))
821 (setf (basic-combination-kind node) :error)
822 (return-from ir1-optimize-combination))))))
824 (let ((attr (fun-info-attributes info)))
825 (when (and (ir1-attributep attr foldable)
826 ;; KLUDGE: The next test could be made more sensitive,
827 ;; only suppressing constant-folding of functions with
828 ;; CALL attributes when they're actually passed
829 ;; function arguments. -- WHN 19990918
830 (not (ir1-attributep attr call))
831 (every #'constant-lvar-p args)
833 (constant-fold-call node)
834 (return-from ir1-optimize-combination)))
836 (let ((fun (fun-info-derive-type info)))
838 (let ((res (funcall fun node)))
840 (derive-node-type node (coerce-to-values res))
841 (maybe-terminate-block node nil)))))
843 (let ((fun (fun-info-optimizer info)))
844 (unless (and fun (funcall fun node))
845 ;; First give the VM a peek at the call
846 (multiple-value-bind (style transform)
847 (combination-implementation-style node)
850 ;; The VM knows how to handle this.
853 ;; The VM mostly knows how to handle this. We need
854 ;; to massage the call slightly, though.
855 (transform-call node transform (combination-fun-source-name node)))
857 ;; Let transforms have a crack at it.
858 (dolist (x (fun-info-transforms info))
860 (when *show-transforms-p*
861 (let* ((lvar (basic-combination-fun node))
862 (fname (lvar-fun-name lvar t)))
863 (/show "trying transform" x (transform-function x) "for" fname)))
864 (unless (ir1-transform node x)
866 (when *show-transforms-p*
867 (/show "quitting because IR1-TRANSFORM result was NIL"))
872 (defun xep-tail-combination-p (node)
873 (and (combination-p node)
874 (let* ((lvar (combination-lvar node))
875 (dest (when (lvar-p lvar) (lvar-dest lvar)))
876 (lambda (when (return-p dest) (return-lambda dest))))
877 (and (lambda-p lambda)
878 (eq :external (lambda-kind lambda))))))
880 ;;; If NODE doesn't return (i.e. return type is NIL), then terminate
881 ;;; the block there, and link it to the component tail.
883 ;;; Except when called during IR1 convertion, we delete the
884 ;;; continuation if it has no other uses. (If it does have other uses,
887 ;;; Termination on the basis of a continuation type is
889 ;;; -- The continuation is deleted (hence the assertion is spurious), or
890 ;;; -- We are in IR1 conversion (where THE assertions are subject to
891 ;;; weakening.) FIXME: Now THE assertions are not weakened, but new
892 ;;; uses can(?) be added later. -- APD, 2003-07-17
894 ;;; Why do we need to consider LVAR type? -- APD, 2003-07-30
895 (defun maybe-terminate-block (node ir1-converting-not-optimizing-p)
896 (declare (type (or basic-combination cast ref) node))
897 (let* ((block (node-block node))
898 (lvar (node-lvar node))
899 (ctran (node-next node))
900 (tail (component-tail (block-component block)))
901 (succ (first (block-succ block))))
902 (declare (ignore lvar))
903 (unless (or (and (eq node (block-last block)) (eq succ tail))
904 (block-delete-p block))
905 ;; Even if the combination will never return, don't terminate if this
906 ;; is the tail call of a XEP: doing that would inhibit TCO.
907 (when (and (eq (node-derived-type node) *empty-type*)
908 (not (xep-tail-combination-p node)))
909 (cond (ir1-converting-not-optimizing-p
912 (aver (eq (block-last block) node)))
914 (setf (block-last block) node)
915 (setf (ctran-use ctran) nil)
916 (setf (ctran-kind ctran) :unused)
917 (setf (ctran-block ctran) nil)
918 (setf (node-next node) nil)
919 (link-blocks block (ctran-starts-block ctran)))))
921 (node-ends-block node)))
923 (let ((succ (first (block-succ block))))
924 (unlink-blocks block succ)
925 (setf (component-reanalyze (block-component block)) t)
926 (aver (not (block-succ block)))
927 (link-blocks block tail)
928 (cond (ir1-converting-not-optimizing-p
929 (%delete-lvar-use node))
930 (t (delete-lvar-use node)
931 (when (null (block-pred succ))
932 (mark-for-deletion succ)))))
935 ;;; This is called both by IR1 conversion and IR1 optimization when
936 ;;; they have verified the type signature for the call, and are
937 ;;; wondering if something should be done to special-case the call. If
938 ;;; CALL is a call to a global function, then see whether it defined
940 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
941 ;;; the expansion and change the call to call it. Expansion is
942 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
943 ;;; true, we never expand, since this function has already been
944 ;;; converted. Local call analysis will duplicate the definition
945 ;;; if necessary. We claim that the parent form is LABELS for
946 ;;; context declarations, since we don't want it to be considered
947 ;;; a real global function.
948 ;;; -- If it is a known function, mark it as such by setting the KIND.
950 ;;; We return the leaf referenced (NIL if not a leaf) and the
951 ;;; FUN-INFO assigned.
952 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
953 (declare (type combination call))
954 (let* ((ref (lvar-uses (basic-combination-fun call)))
955 (leaf (when (ref-p ref) (ref-leaf ref)))
956 (inlinep (if (defined-fun-p leaf)
957 (defined-fun-inlinep leaf)
960 ((eq inlinep :notinline)
961 (let ((info (info :function :info (leaf-source-name leaf))))
963 (setf (basic-combination-fun-info call) info))
965 ((not (and (global-var-p leaf)
966 (eq (global-var-kind leaf) :global-function)))
971 ((nil :maybe-inline) (policy call (zerop space))))
973 (defined-fun-inline-expansion leaf)
974 (inline-expansion-ok call))
975 ;; Inline: if the function has already been converted at another call
976 ;; site in this component, we point this REF to the functional. If not,
977 ;; we convert the expansion.
979 ;; For :INLINE case local call analysis will copy the expansion later,
980 ;; but for :MAYBE-INLINE and NIL cases we only get one copy of the
981 ;; expansion per component.
983 ;; FIXME: We also convert in :INLINE & FUNCTIONAL-KIND case below. What
986 (let* ((name (leaf-source-name leaf))
987 (res (ir1-convert-inline-expansion
989 (defined-fun-inline-expansion leaf)
992 (info :function :info name))))
993 ;; Allow backward references to this function from following
994 ;; forms. (Reused only if policy matches.)
995 (push res (defined-fun-functionals leaf))
996 (change-ref-leaf ref res))))
997 (let ((fun (defined-fun-functional leaf)))
999 (and (eq inlinep :inline) (functional-kind fun)))
1001 (if ir1-converting-not-optimizing-p
1003 (with-ir1-environment-from-node call
1005 (locall-analyze-component *current-component*)))
1006 ;; If we've already converted, change ref to the converted
1008 (change-ref-leaf ref fun))))
1009 (values (ref-leaf ref) nil))
1011 (let ((info (info :function :info (leaf-source-name leaf))))
1015 (setf (basic-combination-kind call) :known)
1016 (setf (basic-combination-fun-info call) info)))
1017 (values leaf nil)))))))
1019 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
1020 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
1021 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
1022 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
1023 ;;; syntax check, arg/result type processing, but still call
1024 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
1025 ;;; and that checking is done by local call analysis.
1026 (defun validate-call-type (call type defined-type ir1-converting-not-optimizing-p)
1027 (declare (type combination call) (type ctype type))
1028 (cond ((not (fun-type-p type))
1029 (aver (multiple-value-bind (val win)
1030 (csubtypep type (specifier-type 'function))
1031 (or val (not win))))
1032 ;; In the commonish case where the function has been defined
1033 ;; in another file, we only get FUNCTION for the type; but we
1034 ;; can check whether the current call is valid for the
1035 ;; existing definition, even if only to STYLE-WARN about it.
1037 (valid-fun-use call defined-type
1038 :argument-test #'always-subtypep
1040 :lossage-fun #'compiler-style-warn
1041 :unwinnage-fun #'compiler-notify))
1042 (recognize-known-call call ir1-converting-not-optimizing-p))
1043 ((valid-fun-use call type
1044 :argument-test #'always-subtypep
1046 ;; KLUDGE: Common Lisp is such a dynamic
1047 ;; language that all we can do here in
1048 ;; general is issue a STYLE-WARNING. It
1049 ;; would be nice to issue a full WARNING
1050 ;; in the special case of of type
1051 ;; mismatches within a compilation unit
1052 ;; (as in section 3.2.2.3 of the spec)
1053 ;; but at least as of sbcl-0.6.11, we
1054 ;; don't keep track of whether the
1055 ;; mismatched data came from the same
1056 ;; compilation unit, so we can't do that.
1057 ;; -- WHN 2001-02-11
1059 ;; FIXME: Actually, I think we could
1060 ;; issue a full WARNING if the call
1061 ;; violates a DECLAIM FTYPE.
1062 :lossage-fun #'compiler-style-warn
1063 :unwinnage-fun #'compiler-notify)
1064 (assert-call-type call type)
1065 (maybe-terminate-block call ir1-converting-not-optimizing-p)
1066 (recognize-known-call call ir1-converting-not-optimizing-p))
1068 (setf (combination-kind call) :error)
1071 ;;; This is called by IR1-OPTIMIZE when the function for a call has
1072 ;;; changed. If the call is local, we try to LET-convert it, and
1073 ;;; derive the result type. If it is a :FULL call, we validate it
1074 ;;; against the type, which recognizes known calls, does inline
1075 ;;; expansion, etc. If a call to a predicate in a non-conditional
1076 ;;; position or to a function with a source transform, then we
1077 ;;; reconvert the form to give IR1 another chance.
1078 (defun propagate-fun-change (call)
1079 (declare (type combination call))
1080 (let ((*compiler-error-context* call)
1081 (fun-lvar (basic-combination-fun call)))
1082 (setf (lvar-reoptimize fun-lvar) nil)
1083 (case (combination-kind call)
1085 (let ((fun (combination-lambda call)))
1086 (maybe-let-convert fun)
1087 (unless (member (functional-kind fun) '(:let :assignment :deleted))
1088 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
1090 (multiple-value-bind (leaf info)
1091 (validate-call-type call (lvar-type fun-lvar) nil nil)
1092 (cond ((functional-p leaf)
1093 (convert-call-if-possible
1094 (lvar-uses (basic-combination-fun call))
1097 ((and (global-var-p leaf)
1098 (eq (global-var-kind leaf) :global-function)
1099 (leaf-has-source-name-p leaf)
1100 (or (info :function :source-transform (leaf-source-name leaf))
1102 (ir1-attributep (fun-info-attributes info)
1104 (let ((lvar (node-lvar call)))
1105 (and lvar (not (if-p (lvar-dest lvar))))))))
1106 (let ((name (leaf-source-name leaf))
1107 (dummies (make-gensym-list
1108 (length (combination-args call)))))
1109 (transform-call call
1111 (,@(if (symbolp name)
1115 (leaf-source-name leaf)))))))))
1118 ;;;; known function optimization
1120 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
1121 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
1122 ;;; replace it, otherwise add a new one.
1123 (defun record-optimization-failure (node transform args)
1124 (declare (type combination node) (type transform transform)
1125 (type (or fun-type list) args))
1126 (let* ((table (component-failed-optimizations *component-being-compiled*))
1127 (found (assoc transform (gethash node table))))
1129 (setf (cdr found) args)
1130 (push (cons transform args) (gethash node table))))
1133 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
1134 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
1135 ;;; doing the transform for some reason and FLAME is true, then we
1136 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
1137 ;;; finalize to pick up. We return true if the transform failed, and
1138 ;;; thus further transformation should be attempted. We return false
1139 ;;; if either the transform succeeded or was aborted.
1140 (defun ir1-transform (node transform)
1141 (declare (type combination node) (type transform transform))
1142 (let* ((type (transform-type transform))
1143 (fun (transform-function transform))
1144 (constrained (fun-type-p type))
1145 (table (component-failed-optimizations *component-being-compiled*))
1146 (flame (if (transform-important transform)
1147 (policy node (>= speed inhibit-warnings))
1148 (policy node (> speed inhibit-warnings))))
1149 (*compiler-error-context* node))
1150 (cond ((or (not constrained)
1151 (valid-fun-use node type))
1152 (multiple-value-bind (severity args)
1153 (catch 'give-up-ir1-transform
1154 (transform-call node
1156 (combination-fun-source-name node))
1160 (remhash node table)
1163 (setf (combination-kind node) :error)
1165 (apply #'warn args))
1166 (remhash node table)
1171 (record-optimization-failure node transform args))
1172 (setf (gethash node table)
1173 (remove transform (gethash node table) :key #'car)))
1176 (remhash node table)
1181 :argument-test #'types-equal-or-intersect
1182 :result-test #'values-types-equal-or-intersect))
1183 (record-optimization-failure node transform type)
1188 ;;; When we don't like an IR1 transform, we throw the severity/reason
1191 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1192 ;;; aborting this attempt to transform the call, but admitting the
1193 ;;; possibility that this or some other transform will later succeed.
1194 ;;; If arguments are supplied, they are format arguments for an
1195 ;;; efficiency note.
1197 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1198 ;;; force a normal call to the function at run time. No further
1199 ;;; optimizations will be attempted.
1201 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1202 ;;; delay the transform on the node until later. REASONS specifies
1203 ;;; when the transform will be later retried. The :OPTIMIZE reason
1204 ;;; causes the transform to be delayed until after the current IR1
1205 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1206 ;;; be delayed until after constraint propagation.
1208 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1209 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1210 ;;; do CASE operations on the various REASON values, it might be a
1211 ;;; good idea to go OO, representing the reasons by objects, using
1212 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1213 ;;; SIGNAL instead of THROW.
1214 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1215 (defun give-up-ir1-transform (&rest args)
1216 (throw 'give-up-ir1-transform (values :failure args)))
1217 (defun abort-ir1-transform (&rest args)
1218 (throw 'give-up-ir1-transform (values :aborted args)))
1219 (defun delay-ir1-transform (node &rest reasons)
1220 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1222 (setf *delayed-ir1-transforms*
1223 (acons node reasons *delayed-ir1-transforms*))
1224 (throw 'give-up-ir1-transform :delayed))
1226 (dolist (reason reasons)
1227 (pushnew reason (cdr assoc)))
1228 (throw 'give-up-ir1-transform :delayed)))))
1230 ;;; Clear any delayed transform with no reasons - these should have
1231 ;;; been tried in the last pass. Then remove the reason from the
1232 ;;; delayed transform reasons, and if any become empty then set
1233 ;;; reoptimize flags for the node. Return true if any transforms are
1235 (defun retry-delayed-ir1-transforms (reason)
1236 (setf *delayed-ir1-transforms*
1237 (remove-if-not #'cdr *delayed-ir1-transforms*))
1238 (let ((reoptimize nil))
1239 (dolist (assoc *delayed-ir1-transforms*)
1240 (let ((reasons (remove reason (cdr assoc))))
1241 (setf (cdr assoc) reasons)
1243 (let ((node (car assoc)))
1244 (unless (node-deleted node)
1246 (setf (node-reoptimize node) t)
1247 (let ((block (node-block node)))
1248 (setf (block-reoptimize block) t)
1249 (reoptimize-component (block-component block) :maybe)))))))
1252 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1253 ;;; environment, and then install it as the function for the call
1254 ;;; NODE. We do local call analysis so that the new function is
1255 ;;; integrated into the control flow.
1257 ;;; We require the original function source name in order to generate
1258 ;;; a meaningful debug name for the lambda we set up. (It'd be
1259 ;;; possible to do this starting from debug names as well as source
1260 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1261 ;;; generality, since source names are always known to our callers.)
1262 (defun transform-call (call res source-name)
1263 (declare (type combination call) (list res))
1264 (aver (and (legal-fun-name-p source-name)
1265 (not (eql source-name '.anonymous.))))
1266 (node-ends-block call)
1267 ;; The internal variables of a transform are not going to be
1268 ;; interesting to the debugger, so there's no sense in
1269 ;; suppressing the substitution of variables with only one use
1270 ;; (the extra variables can slow down constraint propagation).
1272 ;; This needs to be done before the WITH-IR1-ENVIRONMENT-FROM-NODE,
1273 ;; so that it will bind *LEXENV* to the right environment.
1274 (setf (combination-lexenv call)
1275 (make-lexenv :default (combination-lexenv call)
1276 :policy (process-optimize-decl
1278 (preserve-single-use-debug-variables 0))
1280 (combination-lexenv call)))))
1281 (with-ir1-environment-from-node call
1282 (with-component-last-block (*current-component*
1283 (block-next (node-block call)))
1285 (let ((new-fun (ir1-convert-inline-lambda
1287 :debug-name (debug-name 'lambda-inlined source-name)
1289 (ref (lvar-use (combination-fun call))))
1290 (change-ref-leaf ref new-fun)
1291 (setf (combination-kind call) :full)
1292 (locall-analyze-component *current-component*))))
1295 ;;; Replace a call to a foldable function of constant arguments with
1296 ;;; the result of evaluating the form. If there is an error during the
1297 ;;; evaluation, we give a warning and leave the call alone, making the
1298 ;;; call a :ERROR call.
1300 ;;; If there is more than one value, then we transform the call into a
1302 (defun constant-fold-call (call)
1303 (let ((args (mapcar #'lvar-value (combination-args call)))
1304 (fun-name (combination-fun-source-name call)))
1305 (multiple-value-bind (values win)
1306 (careful-call fun-name
1309 ;; Note: CMU CL had COMPILER-WARN here, and that
1310 ;; seems more natural, but it's probably not.
1312 ;; It's especially not while bug 173 exists:
1315 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1317 ;; can cause constant-folding TYPE-ERRORs (in
1318 ;; #'<=) when END can be proved to be NIL, even
1319 ;; though the code is perfectly legal and safe
1320 ;; because a NIL value of END means that the
1321 ;; #'<= will never be executed.
1323 ;; Moreover, even without bug 173,
1324 ;; quite-possibly-valid code like
1325 ;; (COND ((NONINLINED-PREDICATE END)
1326 ;; (UNLESS (<= END SIZE))
1328 ;; (where NONINLINED-PREDICATE is something the
1329 ;; compiler can't do at compile time, but which
1330 ;; turns out to make the #'<= expression
1331 ;; unreachable when END=NIL) could cause errors
1332 ;; when the compiler tries to constant-fold (<=
1335 ;; So, with or without bug 173, it'd be
1336 ;; unnecessarily evil to do a full
1337 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1338 ;; from COMPILE-FILE) for legal code, so we we
1339 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1340 #-sb-xc-host #'compiler-style-warn
1341 ;; On the other hand, for code we control, we
1342 ;; should be able to work around any bug
1343 ;; 173-related problems, and in particular we
1344 ;; want to be alerted to calls to our own
1345 ;; functions which aren't being folded away; a
1346 ;; COMPILER-WARNING is butch enough to stop the
1347 ;; SBCL build itself in its tracks.
1348 #+sb-xc-host #'compiler-warn
1351 (setf (combination-kind call) :error))
1352 ((and (proper-list-of-length-p values 1))
1353 (with-ir1-environment-from-node call
1354 (let* ((lvar (node-lvar call))
1355 (prev (node-prev call))
1356 (intermediate-ctran (make-ctran)))
1357 (%delete-lvar-use call)
1358 (setf (ctran-next prev) nil)
1359 (setf (node-prev call) nil)
1360 (reference-constant prev intermediate-ctran lvar
1362 (link-node-to-previous-ctran call intermediate-ctran)
1363 (reoptimize-lvar lvar)
1364 (flush-combination call))))
1365 (t (let ((dummies (make-gensym-list (length args))))
1369 (declare (ignore ,@dummies))
1370 (values ,@(mapcar (lambda (x) `',x) values)))
1374 ;;;; local call optimization
1376 ;;; Propagate TYPE to LEAF and its REFS, marking things changed.
1378 ;;; If the leaf type is a function type, then just leave it alone, since TYPE
1379 ;;; is never going to be more specific than that (and TYPE-INTERSECTION would
1382 ;;; Also, if the type is one requiring special care don't touch it if the leaf
1383 ;;; has multiple references -- otherwise LVAR-CONSERVATIVE-TYPE is screwed.
1384 (defun propagate-to-refs (leaf type)
1385 (declare (type leaf leaf) (type ctype type))
1386 (let ((var-type (leaf-type leaf))
1387 (refs (leaf-refs leaf)))
1388 (unless (or (fun-type-p var-type)
1390 (eq :declared (leaf-where-from leaf))
1391 (type-needs-conservation-p var-type)))
1392 (let ((int (type-approx-intersection2 var-type type)))
1393 (when (type/= int var-type)
1394 (setf (leaf-type leaf) int)
1395 (let ((s-int (make-single-value-type int)))
1397 (derive-node-type ref s-int)
1398 ;; KLUDGE: LET var substitution
1399 (let* ((lvar (node-lvar ref)))
1400 (when (and lvar (combination-p (lvar-dest lvar)))
1401 (reoptimize-lvar lvar)))))))
1404 ;;; Iteration variable: exactly one SETQ of the form:
1406 ;;; (let ((var initial))
1408 ;;; (setq var (+ var step))
1410 (defun maybe-infer-iteration-var-type (var initial-type)
1411 (binding* ((sets (lambda-var-sets var) :exit-if-null)
1413 (() (null (rest sets)) :exit-if-null)
1414 (set-use (principal-lvar-use (set-value set)))
1415 (() (and (combination-p set-use)
1416 (eq (combination-kind set-use) :known)
1417 (fun-info-p (combination-fun-info set-use))
1418 (not (node-to-be-deleted-p set-use))
1419 (or (eq (combination-fun-source-name set-use) '+)
1420 (eq (combination-fun-source-name set-use) '-)))
1422 (minusp (eq (combination-fun-source-name set-use) '-))
1423 (+-args (basic-combination-args set-use))
1424 (() (and (proper-list-of-length-p +-args 2 2)
1425 (let ((first (principal-lvar-use
1428 (eq (ref-leaf first) var))))
1430 (step-type (lvar-type (second +-args)))
1431 (set-type (lvar-type (set-value set))))
1432 (when (and (numeric-type-p initial-type)
1433 (numeric-type-p step-type)
1434 (or (numeric-type-equal initial-type step-type)
1435 ;; Detect cases like (LOOP FOR 1.0 to 5.0 ...), where
1436 ;; the initial and the step are of different types,
1437 ;; and the step is less contagious.
1438 (numeric-type-equal initial-type
1439 (numeric-contagion initial-type
1441 (labels ((leftmost (x y cmp cmp=)
1442 (cond ((eq x nil) nil)
1445 (let ((x1 (first x)))
1447 (let ((y1 (first y)))
1448 (if (funcall cmp x1 y1) x y)))
1450 (if (funcall cmp x1 y) x y)))))
1452 (let ((y1 (first y)))
1453 (if (funcall cmp= x y1) x y)))
1454 (t (if (funcall cmp x y) x y))))
1455 (max* (x y) (leftmost x y #'> #'>=))
1456 (min* (x y) (leftmost x y #'< #'<=)))
1457 (multiple-value-bind (low high)
1458 (let ((step-type-non-negative (csubtypep step-type (specifier-type
1460 (step-type-non-positive (csubtypep step-type (specifier-type
1462 (cond ((or (and step-type-non-negative (not minusp))
1463 (and step-type-non-positive minusp))
1464 (values (numeric-type-low initial-type)
1465 (when (and (numeric-type-p set-type)
1466 (numeric-type-equal set-type initial-type))
1467 (max* (numeric-type-high initial-type)
1468 (numeric-type-high set-type)))))
1469 ((or (and step-type-non-positive (not minusp))
1470 (and step-type-non-negative minusp))
1471 (values (when (and (numeric-type-p set-type)
1472 (numeric-type-equal set-type initial-type))
1473 (min* (numeric-type-low initial-type)
1474 (numeric-type-low set-type)))
1475 (numeric-type-high initial-type)))
1478 (modified-numeric-type initial-type
1481 :enumerable nil))))))
1482 (deftransform + ((x y) * * :result result)
1483 "check for iteration variable reoptimization"
1484 (let ((dest (principal-lvar-end result))
1485 (use (principal-lvar-use x)))
1486 (when (and (ref-p use)
1490 (reoptimize-lvar (set-value dest))))
1491 (give-up-ir1-transform))
1493 ;;; Figure out the type of a LET variable that has sets. We compute
1494 ;;; the union of the INITIAL-TYPE and the types of all the set
1495 ;;; values and to a PROPAGATE-TO-REFS with this type.
1496 (defun propagate-from-sets (var initial-type)
1497 (let ((changes (not (csubtypep (lambda-var-last-initial-type var) initial-type)))
1499 (dolist (set (lambda-var-sets var))
1500 (let ((type (lvar-type (set-value set))))
1502 (when (node-reoptimize set)
1503 (let ((old-type (node-derived-type set)))
1504 (unless (values-subtypep old-type type)
1505 (derive-node-type set (make-single-value-type type))
1507 (setf (node-reoptimize set) nil))))
1509 (setf (lambda-var-last-initial-type var) initial-type)
1510 (let ((res-type (or (maybe-infer-iteration-var-type var initial-type)
1511 (apply #'type-union initial-type types))))
1512 (propagate-to-refs var res-type))))
1515 ;;; If a LET variable, find the initial value's type and do
1516 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1518 (defun ir1-optimize-set (node)
1519 (declare (type cset node))
1520 (let ((var (set-var node)))
1521 (when (and (lambda-var-p var) (leaf-refs var))
1522 (let ((home (lambda-var-home var)))
1523 (when (eq (functional-kind home) :let)
1524 (let* ((initial-value (let-var-initial-value var))
1525 (initial-type (lvar-type initial-value)))
1526 (setf (lvar-reoptimize initial-value) nil)
1527 (propagate-from-sets var initial-type))))))
1528 (derive-node-type node (make-single-value-type
1529 (lvar-type (set-value node))))
1530 (setf (node-reoptimize node) nil)
1533 ;;; Return true if the value of REF will always be the same (and is
1534 ;;; thus legal to substitute.)
1535 (defun constant-reference-p (ref)
1536 (declare (type ref ref))
1537 (let ((leaf (ref-leaf ref)))
1539 ((or constant functional) t)
1541 (null (lambda-var-sets leaf)))
1543 (not (eq (defined-fun-inlinep leaf) :notinline)))
1545 (case (global-var-kind leaf)
1547 (let ((name (leaf-source-name leaf)))
1549 (eq (symbol-package (fun-name-block-name name))
1551 (info :function :info name)))))))))
1553 ;;; If we have a non-set LET var with a single use, then (if possible)
1554 ;;; replace the variable reference's LVAR with the arg lvar.
1556 ;;; We change the REF to be a reference to NIL with unused value, and
1557 ;;; let it be flushed as dead code. A side effect of this substitution
1558 ;;; is to delete the variable.
1559 (defun substitute-single-use-lvar (arg var)
1560 (declare (type lvar arg) (type lambda-var var))
1561 (binding* ((ref (first (leaf-refs var)))
1562 (lvar (node-lvar ref) :exit-if-null)
1563 (dest (lvar-dest lvar)))
1565 ;; Think about (LET ((A ...)) (IF ... A ...)): two
1566 ;; LVAR-USEs should not be met on one path. Another problem
1567 ;; is with dynamic-extent.
1568 (eq (lvar-uses lvar) ref)
1569 (not (block-delete-p (node-block ref)))
1571 ;; we should not change lifetime of unknown values lvars
1573 (and (type-single-value-p (lvar-derived-type arg))
1574 (multiple-value-bind (pdest pprev)
1575 (principal-lvar-end lvar)
1576 (declare (ignore pdest))
1577 (lvar-single-value-p pprev))))
1579 (or (eq (basic-combination-fun dest) lvar)
1580 (and (eq (basic-combination-kind dest) :local)
1581 (type-single-value-p (lvar-derived-type arg)))))
1583 ;; While CRETURN and EXIT nodes may be known-values,
1584 ;; they have their own complications, such as
1585 ;; substitution into CRETURN may create new tail calls.
1588 (aver (lvar-single-value-p lvar))
1590 (eq (node-home-lambda ref)
1591 (lambda-home (lambda-var-home var))))
1592 (let ((ref-type (single-value-type (node-derived-type ref))))
1593 (cond ((csubtypep (single-value-type (lvar-type arg)) ref-type)
1594 (substitute-lvar-uses lvar arg
1595 ;; Really it is (EQ (LVAR-USES LVAR) REF):
1597 (delete-lvar-use ref))
1599 (let* ((value (make-lvar))
1600 (cast (insert-cast-before ref value ref-type
1601 ;; KLUDGE: it should be (TYPE-CHECK 0)
1603 (setf (cast-type-to-check cast) *wild-type*)
1604 (substitute-lvar-uses value arg
1607 (%delete-lvar-use ref)
1608 (add-lvar-use cast lvar)))))
1609 (setf (node-derived-type ref) *wild-type*)
1610 (change-ref-leaf ref (find-constant nil))
1613 (reoptimize-lvar lvar)
1616 ;;; Delete a LET, removing the call and bind nodes, and warning about
1617 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1618 ;;; along right away and delete the REF and then the lambda, since we
1619 ;;; flush the FUN lvar.
1620 (defun delete-let (clambda)
1621 (declare (type clambda clambda))
1622 (aver (functional-letlike-p clambda))
1623 (note-unreferenced-vars clambda)
1624 (let ((call (let-combination clambda)))
1625 (flush-dest (basic-combination-fun call))
1627 (unlink-node (lambda-bind clambda))
1628 (setf (lambda-bind clambda) nil))
1629 (setf (functional-kind clambda) :zombie)
1630 (let ((home (lambda-home clambda)))
1631 (setf (lambda-lets home) (delete clambda (lambda-lets home))))
1634 ;;; This function is called when one of the arguments to a LET
1635 ;;; changes. We look at each changed argument. If the corresponding
1636 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1637 ;;; consider substituting for the variable, and also propagate
1638 ;;; derived-type information for the arg to all the VAR's refs.
1640 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1641 ;;; subtype of the argument's leaf type. This prevents type checking
1642 ;;; from being defeated, and also ensures that the best representation
1643 ;;; for the variable can be used.
1645 ;;; Substitution of individual references is inhibited if the
1646 ;;; reference is in a different component from the home. This can only
1647 ;;; happen with closures over top level lambda vars. In such cases,
1648 ;;; the references may have already been compiled, and thus can't be
1649 ;;; retroactively modified.
1651 ;;; If all of the variables are deleted (have no references) when we
1652 ;;; are done, then we delete the LET.
1654 ;;; Note that we are responsible for clearing the LVAR-REOPTIMIZE
1656 (defun propagate-let-args (call fun)
1657 (declare (type combination call) (type clambda fun))
1658 (loop for arg in (combination-args call)
1659 and var in (lambda-vars fun) do
1660 (when (and arg (lvar-reoptimize arg))
1661 (setf (lvar-reoptimize arg) nil)
1663 ((lambda-var-sets var)
1664 (propagate-from-sets var (lvar-type arg)))
1665 ((let ((use (lvar-uses arg)))
1667 (let ((leaf (ref-leaf use)))
1668 (when (and (constant-reference-p use)
1669 (csubtypep (leaf-type leaf)
1670 ;; (NODE-DERIVED-TYPE USE) would
1671 ;; be better -- APD, 2003-05-15
1673 (propagate-to-refs var (lvar-type arg))
1674 (let ((use-component (node-component use)))
1675 (prog1 (substitute-leaf-if
1677 (cond ((eq (node-component ref) use-component)
1680 (aver (lambda-toplevelish-p (lambda-home fun)))
1684 ((and (null (rest (leaf-refs var)))
1685 ;; Don't substitute single-ref variables on high-debug /
1686 ;; low speed, to improve the debugging experience.
1687 (policy call (< preserve-single-use-debug-variables 3))
1688 (substitute-single-use-lvar arg var)))
1690 (propagate-to-refs var (lvar-type arg))))))
1692 (when (every #'not (combination-args call))
1697 ;;; This function is called when one of the args to a non-LET local
1698 ;;; call changes. For each changed argument corresponding to an unset
1699 ;;; variable, we compute the union of the types across all calls and
1700 ;;; propagate this type information to the var's refs.
1702 ;;; If the function has an XEP, then we don't do anything, since we
1703 ;;; won't discover anything.
1705 ;;; We can clear the LVAR-REOPTIMIZE flags for arguments in all calls
1706 ;;; corresponding to changed arguments in CALL, since the only use in
1707 ;;; IR1 optimization of the REOPTIMIZE flag for local call args is
1709 (defun propagate-local-call-args (call fun)
1710 (declare (type combination call) (type clambda fun))
1711 (unless (or (functional-entry-fun fun)
1712 (lambda-optional-dispatch fun))
1713 (let* ((vars (lambda-vars fun))
1714 (union (mapcar (lambda (arg var)
1716 (lvar-reoptimize arg)
1717 (null (basic-var-sets var)))
1719 (basic-combination-args call)
1721 (this-ref (lvar-use (basic-combination-fun call))))
1723 (dolist (arg (basic-combination-args call))
1725 (setf (lvar-reoptimize arg) nil)))
1727 (dolist (ref (leaf-refs fun))
1728 (let ((dest (node-dest ref)))
1729 (unless (or (eq ref this-ref) (not dest))
1731 (mapcar (lambda (this-arg old)
1733 (setf (lvar-reoptimize this-arg) nil)
1734 (type-union (lvar-type this-arg) old)))
1735 (basic-combination-args dest)
1738 (loop for var in vars
1740 when type do (propagate-to-refs var type))))
1744 ;;;; multiple values optimization
1746 ;;; Do stuff to notice a change to a MV combination node. There are
1747 ;;; two main branches here:
1748 ;;; -- If the call is local, then it is already a MV let, or should
1749 ;;; become one. Note that although all :LOCAL MV calls must eventually
1750 ;;; be converted to :MV-LETs, there can be a window when the call
1751 ;;; is local, but has not been LET converted yet. This is because
1752 ;;; the entry-point lambdas may have stray references (in other
1753 ;;; entry points) that have not been deleted yet.
1754 ;;; -- The call is full. This case is somewhat similar to the non-MV
1755 ;;; combination optimization: we propagate return type information and
1756 ;;; notice non-returning calls. We also have an optimization
1757 ;;; which tries to convert MV-CALLs into MV-binds.
1758 (defun ir1-optimize-mv-combination (node)
1759 (ecase (basic-combination-kind node)
1761 (let ((fun-lvar (basic-combination-fun node)))
1762 (when (lvar-reoptimize fun-lvar)
1763 (setf (lvar-reoptimize fun-lvar) nil)
1764 (maybe-let-convert (combination-lambda node))))
1765 (setf (lvar-reoptimize (first (basic-combination-args node))) nil)
1766 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1767 (unless (convert-mv-bind-to-let node)
1768 (ir1-optimize-mv-bind node))))
1770 (let* ((fun (basic-combination-fun node))
1771 (fun-changed (lvar-reoptimize fun))
1772 (args (basic-combination-args node)))
1774 (setf (lvar-reoptimize fun) nil)
1775 (let ((type (lvar-type fun)))
1776 (when (fun-type-p type)
1777 (derive-node-type node (fun-type-returns type))))
1778 (maybe-terminate-block node nil)
1779 (let ((use (lvar-uses fun)))
1780 (when (and (ref-p use) (functional-p (ref-leaf use)))
1781 (convert-call-if-possible use node)
1782 (when (eq (basic-combination-kind node) :local)
1783 (maybe-let-convert (ref-leaf use))))))
1784 (unless (or (eq (basic-combination-kind node) :local)
1785 (eq (lvar-fun-name fun) '%throw))
1786 (ir1-optimize-mv-call node))
1788 (setf (lvar-reoptimize arg) nil))))
1792 ;;; Propagate derived type info from the values lvar to the vars.
1793 (defun ir1-optimize-mv-bind (node)
1794 (declare (type mv-combination node))
1795 (let* ((arg (first (basic-combination-args node)))
1796 (vars (lambda-vars (combination-lambda node)))
1797 (n-vars (length vars))
1798 (types (values-type-in (lvar-derived-type arg)
1800 (loop for var in vars
1802 do (if (basic-var-sets var)
1803 (propagate-from-sets var type)
1804 (propagate-to-refs var type)))
1805 (setf (lvar-reoptimize arg) nil))
1808 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1810 ;;; -- The call has only one argument, and
1811 ;;; -- The function has a known fixed number of arguments, or
1812 ;;; -- The argument yields a known fixed number of values.
1814 ;;; What we do is change the function in the MV-CALL to be a lambda
1815 ;;; that "looks like an MV bind", which allows
1816 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1817 ;;; converted (the next time around.) This new lambda just calls the
1818 ;;; actual function with the MV-BIND variables as arguments. Note that
1819 ;;; this new MV bind is not let-converted immediately, as there are
1820 ;;; going to be stray references from the entry-point functions until
1821 ;;; they get deleted.
1823 ;;; In order to avoid loss of argument count checking, we only do the
1824 ;;; transformation according to a known number of expected argument if
1825 ;;; safety is unimportant. We can always convert if we know the number
1826 ;;; of actual values, since the normal call that we build will still
1827 ;;; do any appropriate argument count checking.
1829 ;;; We only attempt the transformation if the called function is a
1830 ;;; constant reference. This allows us to just splice the leaf into
1831 ;;; the new function, instead of trying to somehow bind the function
1832 ;;; expression. The leaf must be constant because we are evaluating it
1833 ;;; again in a different place. This also has the effect of squelching
1834 ;;; multiple warnings when there is an argument count error.
1835 (defun ir1-optimize-mv-call (node)
1836 (let ((fun (basic-combination-fun node))
1837 (*compiler-error-context* node)
1838 (ref (lvar-uses (basic-combination-fun node)))
1839 (args (basic-combination-args node)))
1841 (unless (and (ref-p ref) (constant-reference-p ref)
1843 (return-from ir1-optimize-mv-call))
1845 (multiple-value-bind (min max)
1846 (fun-type-nargs (lvar-type fun))
1848 (multiple-value-bind (types nvals)
1849 (values-types (lvar-derived-type (first args)))
1850 (declare (ignore types))
1851 (if (eq nvals :unknown) nil nvals))))
1854 (when (and min (< total-nvals min))
1856 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1859 (setf (basic-combination-kind node) :error)
1860 (return-from ir1-optimize-mv-call))
1861 (when (and max (> total-nvals max))
1863 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1866 (setf (basic-combination-kind node) :error)
1867 (return-from ir1-optimize-mv-call)))
1869 (let ((count (cond (total-nvals)
1870 ((and (policy node (zerop verify-arg-count))
1875 (with-ir1-environment-from-node node
1876 (let* ((dums (make-gensym-list count))
1878 (leaf (ref-leaf ref))
1879 (fun (ir1-convert-lambda
1880 `(lambda (&optional ,@dums &rest ,ignore)
1881 (declare (ignore ,ignore))
1882 (%funcall ,leaf ,@dums))
1883 :source-name (leaf-%source-name leaf)
1884 :debug-name (leaf-%debug-name leaf))))
1885 (change-ref-leaf ref fun)
1886 (aver (eq (basic-combination-kind node) :full))
1887 (locall-analyze-component *current-component*)
1888 (aver (eq (basic-combination-kind node) :local)))))))))
1892 ;;; (multiple-value-bind
1901 ;;; What we actually do is convert the VALUES combination into a
1902 ;;; normal LET combination calling the original :MV-LET lambda. If
1903 ;;; there are extra args to VALUES, discard the corresponding
1904 ;;; lvars. If there are insufficient args, insert references to NIL.
1905 (defun convert-mv-bind-to-let (call)
1906 (declare (type mv-combination call))
1907 (let* ((arg (first (basic-combination-args call)))
1908 (use (lvar-uses arg)))
1909 (when (and (combination-p use)
1910 (eq (lvar-fun-name (combination-fun use))
1912 (let* ((fun (combination-lambda call))
1913 (vars (lambda-vars fun))
1914 (vals (combination-args use))
1915 (nvars (length vars))
1916 (nvals (length vals)))
1917 (cond ((> nvals nvars)
1918 (mapc #'flush-dest (subseq vals nvars))
1919 (setq vals (subseq vals 0 nvars)))
1921 (with-ir1-environment-from-node use
1922 (let ((node-prev (node-prev use)))
1923 (setf (node-prev use) nil)
1924 (setf (ctran-next node-prev) nil)
1925 (collect ((res vals))
1926 (loop for count below (- nvars nvals)
1927 for prev = node-prev then ctran
1928 for ctran = (make-ctran)
1929 and lvar = (make-lvar use)
1930 do (reference-constant prev ctran lvar nil)
1932 finally (link-node-to-previous-ctran
1934 (setq vals (res)))))))
1935 (setf (combination-args use) vals)
1936 (flush-dest (combination-fun use))
1937 (let ((fun-lvar (basic-combination-fun call)))
1938 (setf (lvar-dest fun-lvar) use)
1939 (setf (combination-fun use) fun-lvar)
1940 (flush-lvar-externally-checkable-type fun-lvar))
1941 (setf (combination-kind use) :local)
1942 (setf (functional-kind fun) :let)
1943 (flush-dest (first (basic-combination-args call)))
1946 (reoptimize-lvar (first vals)))
1947 (propagate-to-args use fun)
1948 (reoptimize-call use))
1952 ;;; (values-list (list x y z))
1957 ;;; In implementation, this is somewhat similar to
1958 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1959 ;;; args of the VALUES-LIST call, flushing the old argument lvar
1960 ;;; (allowing the LIST to be flushed.)
1962 ;;; FIXME: Thus we lose possible type assertions on (LIST ...).
1963 (defoptimizer (values-list optimizer) ((list) node)
1964 (let ((use (lvar-uses list)))
1965 (when (and (combination-p use)
1966 (eq (lvar-fun-name (combination-fun use))
1969 ;; FIXME: VALUES might not satisfy an assertion on NODE-LVAR.
1970 (change-ref-leaf (lvar-uses (combination-fun node))
1971 (find-free-fun 'values "in a strange place"))
1972 (setf (combination-kind node) :full)
1973 (let ((args (combination-args use)))
1975 (setf (lvar-dest arg) node)
1976 (flush-lvar-externally-checkable-type arg))
1977 (setf (combination-args use) nil)
1979 (setf (combination-args node) args))
1982 ;;; If VALUES appears in a non-MV context, then effectively convert it
1983 ;;; to a PROG1. This allows the computation of the additional values
1984 ;;; to become dead code.
1985 (deftransform values ((&rest vals) * * :node node)
1986 (unless (lvar-single-value-p (node-lvar node))
1987 (give-up-ir1-transform))
1988 (setf (node-derived-type node)
1989 (make-short-values-type (list (single-value-type
1990 (node-derived-type node)))))
1991 (principal-lvar-single-valuify (node-lvar node))
1993 (let ((dummies (make-gensym-list (length (cdr vals)))))
1994 `(lambda (val ,@dummies)
1995 (declare (ignore ,@dummies))
2001 (defun delete-cast (cast)
2002 (declare (type cast cast))
2003 (let ((value (cast-value cast))
2004 (lvar (node-lvar cast)))
2005 (delete-filter cast lvar value)
2007 (reoptimize-lvar lvar)
2008 (when (lvar-single-value-p lvar)
2009 (note-single-valuified-lvar lvar)))
2012 (defun ir1-optimize-cast (cast &optional do-not-optimize)
2013 (declare (type cast cast))
2014 (let ((value (cast-value cast))
2015 (atype (cast-asserted-type cast)))
2016 (when (not do-not-optimize)
2017 (let ((lvar (node-lvar cast)))
2018 (when (values-subtypep (lvar-derived-type value)
2019 (cast-asserted-type cast))
2021 (return-from ir1-optimize-cast t))
2023 (when (and (listp (lvar-uses value))
2025 ;; Pathwise removing of CAST
2026 (let ((ctran (node-next cast))
2027 (dest (lvar-dest lvar))
2030 (do-uses (use value)
2031 (when (and (values-subtypep (node-derived-type use) atype)
2032 (immediately-used-p value use))
2034 (when ctran (ensure-block-start ctran))
2035 (setq next-block (first (block-succ (node-block cast))))
2036 (ensure-block-start (node-prev cast))
2037 (reoptimize-lvar lvar)
2038 (setf (lvar-%derived-type value) nil))
2039 (%delete-lvar-use use)
2040 (add-lvar-use use lvar)
2041 (unlink-blocks (node-block use) (node-block cast))
2042 (link-blocks (node-block use) next-block)
2043 (when (and (return-p dest)
2044 (basic-combination-p use)
2045 (eq (basic-combination-kind use) :local))
2047 (dolist (use (merges))
2048 (merge-tail-sets use)))))))
2050 (let* ((value-type (lvar-derived-type value))
2051 (int (values-type-intersection value-type atype)))
2052 (derive-node-type cast int)
2053 (when (eq int *empty-type*)
2054 (unless (eq value-type *empty-type*)
2056 ;; FIXME: Do it in one step.
2059 (if (cast-single-value-p cast)
2061 `(multiple-value-call #'list 'dummy)))
2064 ;; FIXME: Derived type.
2065 `(%compile-time-type-error 'dummy
2066 ',(type-specifier atype)
2067 ',(type-specifier value-type)))
2068 ;; KLUDGE: FILTER-LVAR does not work for non-returning
2069 ;; functions, so we declare the return type of
2070 ;; %COMPILE-TIME-TYPE-ERROR to be * and derive the real type
2072 (setq value (cast-value cast))
2073 (derive-node-type (lvar-uses value) *empty-type*)
2074 (maybe-terminate-block (lvar-uses value) nil)
2075 ;; FIXME: Is it necessary?
2076 (aver (null (block-pred (node-block cast))))
2077 (delete-block-lazily (node-block cast))
2078 (return-from ir1-optimize-cast)))
2079 (when (eq (node-derived-type cast) *empty-type*)
2080 (maybe-terminate-block cast nil))
2082 (when (and (cast-%type-check cast)
2083 (values-subtypep value-type
2084 (cast-type-to-check cast)))
2085 (setf (cast-%type-check cast) nil))))
2087 (unless do-not-optimize
2088 (setf (node-reoptimize cast) nil)))
2090 (deftransform make-symbol ((string) (simple-string))
2091 `(%make-symbol string))