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 #!-sb-fluid (declaim (inline lvar-derived-type))
46 (defun lvar-derived-type (lvar)
47 (declare (type lvar lvar))
48 (or (lvar-%derived-type lvar)
49 (setf (lvar-%derived-type lvar)
50 (%lvar-derived-type lvar))))
51 (defun %lvar-derived-type (lvar)
52 (declare (type lvar lvar))
53 (let ((uses (lvar-uses lvar)))
54 (cond ((null uses) *empty-type*)
56 (do ((res (node-derived-type (first uses))
57 (values-type-union (node-derived-type (first current))
59 (current (rest uses) (rest current)))
60 ((or (null current) (eq res *wild-type*))
63 (node-derived-type uses)))))
65 ;;; Return the derived type for LVAR's first value. This is guaranteed
66 ;;; not to be a VALUES or FUNCTION type.
67 (declaim (ftype (sfunction (lvar) ctype) lvar-type))
68 (defun lvar-type (lvar)
69 (single-value-type (lvar-derived-type lvar)))
71 ;;; If LVAR is an argument of a function, return a type which the
72 ;;; function checks LVAR for.
73 #!-sb-fluid (declaim (inline lvar-externally-checkable-type))
74 (defun lvar-externally-checkable-type (lvar)
75 (or (lvar-%externally-checkable-type lvar)
76 (%lvar-%externally-checkable-type lvar)))
77 (defun %lvar-%externally-checkable-type (lvar)
78 (declare (type lvar lvar))
79 (let ((dest (lvar-dest lvar)))
80 (if (not (and dest (combination-p dest)))
81 ;; TODO: MV-COMBINATION
82 (setf (lvar-%externally-checkable-type lvar) *wild-type*)
83 (let* ((fun (combination-fun dest))
84 (args (combination-args dest))
85 (fun-type (lvar-type fun)))
86 (setf (lvar-%externally-checkable-type fun) *wild-type*)
87 (if (or (not (call-full-like-p dest))
88 (not (fun-type-p fun-type))
89 ;; FUN-TYPE might be (AND FUNCTION (SATISFIES ...)).
90 (fun-type-wild-args fun-type))
93 (setf (lvar-%externally-checkable-type arg)
95 (map-combination-args-and-types
97 (setf (lvar-%externally-checkable-type arg)
98 (acond ((lvar-%externally-checkable-type arg)
99 (values-type-intersection
100 it (coerce-to-values type)))
101 (t (coerce-to-values type)))))
103 (lvar-%externally-checkable-type lvar))
104 #!-sb-fluid(declaim (inline flush-lvar-externally-checkable-type))
105 (defun flush-lvar-externally-checkable-type (lvar)
106 (declare (type lvar lvar))
107 (setf (lvar-%externally-checkable-type lvar) nil))
109 ;;;; interface routines used by optimizers
111 (declaim (inline reoptimize-component))
112 (defun reoptimize-component (component kind)
113 (declare (type component component)
114 (type (member nil :maybe t) kind))
116 (unless (eq (component-reoptimize component) t)
117 (setf (component-reoptimize component) kind)))
119 ;;; This function is called by optimizers to indicate that something
120 ;;; interesting has happened to the value of LVAR. Optimizers must
121 ;;; make sure that they don't call for reoptimization when nothing has
122 ;;; happened, since optimization will fail to terminate.
124 ;;; We clear any cached type for the lvar and set the reoptimize flags
125 ;;; on everything in sight.
126 (defun reoptimize-lvar (lvar)
127 (declare (type (or lvar null) lvar))
129 (setf (lvar-%derived-type lvar) nil)
130 (let ((dest (lvar-dest lvar)))
132 (setf (lvar-reoptimize lvar) t)
133 (setf (node-reoptimize dest) t)
134 (binding* (;; Since this may be called during IR1 conversion,
135 ;; PREV may be missing.
136 (prev (node-prev dest) :exit-if-null)
137 (block (ctran-block prev))
138 (component (block-component block)))
139 (when (typep dest 'cif)
140 (setf (block-test-modified block) t))
141 (setf (block-reoptimize block) t)
142 (reoptimize-component component :maybe))))
144 (setf (block-type-check (node-block node)) t)))
147 (defun reoptimize-lvar-uses (lvar)
148 (declare (type lvar lvar))
150 (setf (node-reoptimize use) t)
151 (setf (block-reoptimize (node-block use)) t)
152 (reoptimize-component (node-component use) :maybe)))
154 ;;; Annotate NODE to indicate that its result has been proven to be
155 ;;; TYPEP to RTYPE. After IR1 conversion has happened, this is the
156 ;;; only correct way to supply information discovered about a node's
157 ;;; type. If you screw with the NODE-DERIVED-TYPE directly, then
158 ;;; information may be lost and reoptimization may not happen.
160 ;;; What we do is intersect RTYPE with NODE's DERIVED-TYPE. If the
161 ;;; intersection is different from the old type, then we do a
162 ;;; REOPTIMIZE-LVAR on the NODE-LVAR.
163 (defun derive-node-type (node rtype)
164 (declare (type valued-node node) (type ctype rtype))
165 (let ((node-type (node-derived-type node)))
166 (unless (eq node-type rtype)
167 (let ((int (values-type-intersection node-type rtype))
168 (lvar (node-lvar node)))
169 (when (type/= node-type int)
170 (when (and *check-consistency*
171 (eq int *empty-type*)
172 (not (eq rtype *empty-type*)))
173 (let ((*compiler-error-context* node))
175 "New inferred type ~S conflicts with old type:~
176 ~% ~S~%*** possible internal error? Please report this."
177 (type-specifier rtype) (type-specifier node-type))))
178 (setf (node-derived-type node) int)
179 ;; If the new type consists of only one object, replace the
180 ;; node with a constant reference.
181 (when (and (ref-p node)
182 (lambda-var-p (ref-leaf node)))
183 (let ((type (single-value-type int)))
184 (when (and (member-type-p type)
185 (eql 1 (member-type-size type)))
186 (change-ref-leaf node (find-constant
187 (first (member-type-members type)))))))
188 (reoptimize-lvar lvar)))))
191 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
192 ;;; error for LVAR's value not to be TYPEP to TYPE. We implement it
193 ;;; splitting off DEST a new CAST node; old LVAR will deliver values
194 ;;; to CAST. If we improve the assertion, we set TYPE-CHECK and
195 ;;; TYPE-ASSERTED to guarantee that the new assertion will be checked.
196 (defun assert-lvar-type (lvar type policy)
197 (declare (type lvar lvar) (type ctype type))
198 (unless (values-subtypep (lvar-derived-type lvar) type)
199 (let ((internal-lvar (make-lvar))
200 (dest (lvar-dest lvar)))
201 (substitute-lvar internal-lvar lvar)
202 (let ((cast (insert-cast-before dest lvar type policy)))
203 (use-lvar cast internal-lvar))))
209 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
210 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
211 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
212 ;;; we are done, then another iteration would be beneficial.
213 (defun ir1-optimize (component fastp)
214 (declare (type component component))
215 (setf (component-reoptimize component) nil)
216 (loop with block = (block-next (component-head component))
217 with tail = (component-tail component)
218 for last-block = block
219 until (eq block tail)
221 ;; We delete blocks when there is either no predecessor or the
222 ;; block is in a lambda that has been deleted. These blocks
223 ;; would eventually be deleted by DFO recomputation, but doing
224 ;; it here immediately makes the effect available to IR1
226 ((or (block-delete-p block)
227 (null (block-pred block)))
228 (delete-block-lazily block)
229 (setq block (clean-component component block)))
230 ((eq (functional-kind (block-home-lambda block)) :deleted)
231 ;; Preserve the BLOCK-SUCC invariant that almost every block has
232 ;; one successor (and a block with DELETE-P set is an acceptable
234 (mark-for-deletion block)
235 (setq block (clean-component component block)))
238 (let ((succ (block-succ block)))
239 (unless (singleton-p succ)
242 (let ((last (block-last block)))
245 (flush-dest (if-test last))
246 (when (unlink-node last)
249 (when (maybe-delete-exit last)
252 (unless (join-successor-if-possible block)
255 (when (and (not fastp) (block-reoptimize block) (block-component block))
256 (aver (not (block-delete-p block)))
257 (ir1-optimize-block block))
259 (cond ((and (block-delete-p block) (block-component block))
260 (setq block (clean-component component block)))
261 ((and (block-flush-p block) (block-component block))
262 (flush-dead-code block)))))
263 do (when (eq block last-block)
264 (setq block (block-next block))))
268 ;;; Loop over the nodes in BLOCK, acting on (and clearing) REOPTIMIZE
271 ;;; Note that although they are cleared here, REOPTIMIZE flags might
272 ;;; still be set upon return from this function, meaning that further
273 ;;; optimization is wanted (as a consequence of optimizations we did).
274 (defun ir1-optimize-block (block)
275 (declare (type cblock block))
276 ;; We clear the node and block REOPTIMIZE flags before doing the
277 ;; optimization, not after. This ensures that the node or block will
278 ;; be reoptimized if necessary.
279 (setf (block-reoptimize block) nil)
280 (do-nodes (node nil block :restart-p t)
281 (when (node-reoptimize node)
282 ;; As above, we clear the node REOPTIMIZE flag before optimizing.
283 (setf (node-reoptimize node) nil)
287 ;; With a COMBINATION, we call PROPAGATE-FUN-CHANGE whenever
288 ;; the function changes, and call IR1-OPTIMIZE-COMBINATION if
289 ;; any argument changes.
290 (ir1-optimize-combination node))
292 (ir1-optimize-if node))
294 ;; KLUDGE: We leave the NODE-OPTIMIZE flag set going into
295 ;; IR1-OPTIMIZE-RETURN, since IR1-OPTIMIZE-RETURN wants to
296 ;; clear the flag itself. -- WHN 2002-02-02, quoting original
298 (setf (node-reoptimize node) t)
299 (ir1-optimize-return node))
301 (ir1-optimize-mv-combination node))
303 ;; With an EXIT, we derive the node's type from the VALUE's
305 (let ((value (exit-value node)))
307 (derive-node-type node (lvar-derived-type value)))))
309 ;; PROPAGATE-FROM-SETS can do a better job if NODE-REOPTIMIZE
310 ;; is accurate till the node actually has been reoptimized.
311 (setf (node-reoptimize node) t)
312 (ir1-optimize-set node))
314 (ir1-optimize-cast node)))))
318 ;;; Try to join with a successor block. If we succeed, we return true,
320 (defun join-successor-if-possible (block)
321 (declare (type cblock block))
322 (let ((next (first (block-succ block))))
323 (when (block-start next) ; NEXT is not an END-OF-COMPONENT marker
324 (cond ( ;; We cannot combine with a successor block if:
326 ;; the successor has more than one predecessor;
327 (rest (block-pred next))
328 ;; the successor is the current block (infinite loop);
330 ;; the next block has a different cleanup, and thus
331 ;; we may want to insert cleanup code between the
332 ;; two blocks at some point;
333 (not (eq (block-end-cleanup block)
334 (block-start-cleanup next)))
335 ;; the next block has a different home lambda, and
336 ;; thus the control transfer is a non-local exit.
337 (not (eq (block-home-lambda block)
338 (block-home-lambda next)))
339 ;; Stack analysis phase wants ENTRY to start a block...
340 (entry-p (block-start-node next))
341 (let ((last (block-last block)))
342 (and (valued-node-p last)
343 (awhen (node-lvar last)
345 ;; ... and a DX-allocator to end a block.
346 (lvar-dynamic-extent it)
347 ;; FIXME: This is a partial workaround for bug 303.
348 (consp (lvar-uses it)))))))
351 (join-blocks block next)
354 ;;; Join together two blocks. The code in BLOCK2 is moved into BLOCK1
355 ;;; and BLOCK2 is deleted from the DFO. We combine the optimize flags
356 ;;; for the two blocks so that any indicated optimization gets done.
357 (defun join-blocks (block1 block2)
358 (declare (type cblock block1 block2))
359 (let* ((last1 (block-last block1))
360 (last2 (block-last block2))
361 (succ (block-succ block2))
362 (start2 (block-start block2)))
363 (do ((ctran start2 (node-next (ctran-next ctran))))
365 (setf (ctran-block ctran) block1))
367 (unlink-blocks block1 block2)
369 (unlink-blocks block2 block)
370 (link-blocks block1 block))
372 (setf (ctran-kind start2) :inside-block)
373 (setf (node-next last1) start2)
374 (setf (ctran-use start2) last1)
375 (setf (block-last block1) last2))
377 (setf (block-flags block1)
378 (attributes-union (block-flags block1)
380 (block-attributes type-asserted test-modified)))
382 (let ((next (block-next block2))
383 (prev (block-prev block2)))
384 (setf (block-next prev) next)
385 (setf (block-prev next) prev))
389 ;;; Delete any nodes in BLOCK whose value is unused and which have no
390 ;;; side effects. We can delete sets of lexical variables when the set
391 ;;; variable has no references.
392 (defun flush-dead-code (block)
393 (declare (type cblock block))
394 (setf (block-flush-p block) nil)
395 (do-nodes-backwards (node lvar block :restart-p t)
402 (let ((kind (combination-kind node))
403 (info (combination-fun-info node)))
404 (when (and (eq kind :known) (fun-info-p info))
405 (let ((attr (fun-info-attributes info)))
406 (when (and (not (ir1-attributep attr call))
407 ;; ### For now, don't delete potentially
408 ;; flushable calls when they have the CALL
409 ;; attribute. Someday we should look at the
410 ;; functional args to determine if they have
412 (if (policy node (= safety 3))
413 (ir1-attributep attr flushable)
414 (ir1-attributep attr unsafely-flushable)))
415 (flush-combination node))))))
417 (when (eq (basic-combination-kind node) :local)
418 (let ((fun (combination-lambda node)))
419 (when (dolist (var (lambda-vars fun) t)
420 (when (or (leaf-refs var)
421 (lambda-var-sets var))
423 (flush-dest (first (basic-combination-args node)))
426 (let ((value (exit-value node)))
429 (setf (exit-value node) nil))))
431 (let ((var (set-var node)))
432 (when (and (lambda-var-p var)
433 (null (leaf-refs var)))
434 (flush-dest (set-value node))
435 (setf (basic-var-sets var)
436 (delq node (basic-var-sets var)))
437 (unlink-node node))))
439 (unless (cast-type-check node)
440 (flush-dest (cast-value node))
441 (unlink-node node))))))
445 ;;;; local call return type propagation
447 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
448 ;;; flag set. It iterates over the uses of the RESULT, looking for
449 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
450 ;;; call, then we union its type together with the types of other such
451 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
452 ;;; type with the RESULT's asserted type. We can make this
453 ;;; intersection now (potentially before type checking) because this
454 ;;; assertion on the result will eventually be checked (if
457 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
458 ;;; combination, which may change the successor of the call to be the
459 ;;; called function, and if so, checks if the call can become an
460 ;;; assignment. If we convert to an assignment, we abort, since the
461 ;;; RETURN has been deleted.
462 (defun find-result-type (node)
463 (declare (type creturn node))
464 (let ((result (return-result node)))
465 (collect ((use-union *empty-type* values-type-union))
466 (do-uses (use result)
467 (let ((use-home (node-home-lambda use)))
468 (cond ((or (eq (functional-kind use-home) :deleted)
469 (block-delete-p (node-block use))))
470 ((and (basic-combination-p use)
471 (eq (basic-combination-kind use) :local))
472 (aver (eq (lambda-tail-set use-home)
473 (lambda-tail-set (combination-lambda use))))
474 (when (combination-p use)
475 (when (nth-value 1 (maybe-convert-tail-local-call use))
476 (return-from find-result-type t))))
478 (use-union (node-derived-type use))))))
480 ;; (values-type-intersection
481 ;; (continuation-asserted-type result) ; FIXME -- APD, 2002-01-26
485 (setf (return-result-type node) int))))
488 ;;; Do stuff to realize that something has changed about the value
489 ;;; delivered to a return node. Since we consider the return values of
490 ;;; all functions in the tail set to be equivalent, this amounts to
491 ;;; bringing the entire tail set up to date. We iterate over the
492 ;;; returns for all the functions in the tail set, reanalyzing them
493 ;;; all (not treating NODE specially.)
495 ;;; When we are done, we check whether the new type is different from
496 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
497 ;;; all the lvars for references to functions in the tail set. This
498 ;;; will cause IR1-OPTIMIZE-COMBINATION to derive the new type as the
499 ;;; results of the calls.
500 (defun ir1-optimize-return (node)
501 (declare (type creturn node))
504 (let* ((tails (lambda-tail-set (return-lambda node)))
505 (funs (tail-set-funs tails)))
506 (collect ((res *empty-type* values-type-union))
508 (let ((return (lambda-return fun)))
510 (when (node-reoptimize return)
511 (setf (node-reoptimize return) nil)
512 (when (find-result-type return)
514 (res (return-result-type return)))))
516 (when (type/= (res) (tail-set-type tails))
517 (setf (tail-set-type tails) (res))
518 (dolist (fun (tail-set-funs tails))
519 (dolist (ref (leaf-refs fun))
520 (reoptimize-lvar (node-lvar ref))))))))
526 ;;; If the test has multiple uses, replicate the node when possible.
527 ;;; Also check whether the predicate is known to be true or false,
528 ;;; deleting the IF node in favor of the appropriate branch when this
530 (defun ir1-optimize-if (node)
531 (declare (type cif node))
532 (let ((test (if-test node))
533 (block (node-block node)))
535 (when (and (eq (block-start-node block) node)
536 (listp (lvar-uses test)))
538 (when (immediately-used-p test use)
539 (convert-if-if use node)
540 (when (not (listp (lvar-uses test))) (return)))))
542 (let* ((type (lvar-type test))
544 (cond ((constant-lvar-p test)
545 (if (lvar-value test)
546 (if-alternative node)
547 (if-consequent node)))
548 ((not (types-equal-or-intersect type (specifier-type 'null)))
549 (if-alternative node))
550 ((type= type (specifier-type 'null))
551 (if-consequent node)))))
554 (when (rest (block-succ block))
555 (unlink-blocks block victim))
556 (setf (component-reanalyze (node-component node)) t)
557 (unlink-node node))))
560 ;;; Create a new copy of an IF node that tests the value of the node
561 ;;; USE. The test must have >1 use, and must be immediately used by
562 ;;; USE. NODE must be the only node in its block (implying that
563 ;;; block-start = if-test).
565 ;;; This optimization has an effect semantically similar to the
566 ;;; source-to-source transformation:
567 ;;; (IF (IF A B C) D E) ==>
568 ;;; (IF A (IF B D E) (IF C D E))
570 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
571 ;;; node so that dead code deletion notes will definitely not consider
572 ;;; either node to be part of the original source. One node might
573 ;;; become unreachable, resulting in a spurious note.
574 (defun convert-if-if (use node)
575 (declare (type node use) (type cif node))
576 (with-ir1-environment-from-node node
577 (let* ((block (node-block node))
578 (test (if-test node))
579 (cblock (if-consequent node))
580 (ablock (if-alternative node))
581 (use-block (node-block use))
582 (new-ctran (make-ctran))
583 (new-lvar (make-lvar))
584 (new-node (make-if :test new-lvar
586 :alternative ablock))
587 (new-block (ctran-starts-block new-ctran)))
588 (link-node-to-previous-ctran new-node new-ctran)
589 (setf (lvar-dest new-lvar) new-node)
590 (setf (block-last new-block) new-node)
592 (unlink-blocks use-block block)
593 (%delete-lvar-use use)
594 (add-lvar-use use new-lvar)
595 (link-blocks use-block new-block)
597 (link-blocks new-block cblock)
598 (link-blocks new-block ablock)
600 (push "<IF Duplication>" (node-source-path node))
601 (push "<IF Duplication>" (node-source-path new-node))
603 (reoptimize-lvar test)
604 (reoptimize-lvar new-lvar)
605 (setf (component-reanalyze *current-component*) t)))
608 ;;;; exit IR1 optimization
610 ;;; This function attempts to delete an exit node, returning true if
611 ;;; it deletes the block as a consequence:
612 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
613 ;;; anything, since there is nothing to be done.
614 ;;; -- If the exit node and its ENTRY have the same home lambda then
615 ;;; we know the exit is local, and can delete the exit. We change
616 ;;; uses of the Exit-Value to be uses of the original lvar,
617 ;;; then unlink the node. If the exit is to a TR context, then we
618 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
619 ;;; their value to this exit.
620 ;;; -- If there is no value (as in a GO), then we skip the value
623 ;;; This function is also called by environment analysis, since it
624 ;;; wants all exits to be optimized even if normal optimization was
626 (defun maybe-delete-exit (node)
627 (declare (type exit node))
628 (let ((value (exit-value node))
629 (entry (exit-entry node)))
631 (eq (node-home-lambda node) (node-home-lambda entry)))
632 (setf (entry-exits entry) (delq node (entry-exits entry)))
634 (delete-filter node (node-lvar node) value)
635 (unlink-node node)))))
638 ;;;; combination IR1 optimization
640 ;;; Report as we try each transform?
642 (defvar *show-transforms-p* nil)
644 (defun check-important-result (node info)
645 (when (and (null (node-lvar node))
646 (ir1-attributep (fun-info-attributes info) important-result))
647 (let ((*compiler-error-context* node))
649 "The return value of ~A should not be discarded."
650 (lvar-fun-name (basic-combination-fun node))))))
652 ;;; Do IR1 optimizations on a COMBINATION node.
653 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
654 (defun ir1-optimize-combination (node)
655 (when (lvar-reoptimize (basic-combination-fun node))
656 (propagate-fun-change node)
657 (maybe-terminate-block node nil))
658 (let ((args (basic-combination-args node))
659 (kind (basic-combination-kind node))
660 (info (basic-combination-fun-info node)))
663 (let ((fun (combination-lambda node)))
664 (if (eq (functional-kind fun) :let)
665 (propagate-let-args node fun)
666 (propagate-local-call-args node fun))))
670 (setf (lvar-reoptimize arg) nil))))
674 (setf (lvar-reoptimize arg) nil)))
676 (check-important-result node info)
677 (let ((fun (fun-info-destroyed-constant-args info)))
679 (let ((destroyed-constant-args (funcall fun args)))
680 (when destroyed-constant-args
681 (let ((*compiler-error-context* node))
682 (warn 'constant-modified
683 :fun-name (lvar-fun-name
684 (basic-combination-fun node)))
685 (setf (basic-combination-kind node) :error)
686 (return-from ir1-optimize-combination))))))
687 (let ((fun (fun-info-derive-type info)))
689 (let ((res (funcall fun node)))
691 (derive-node-type node (coerce-to-values res))
692 (maybe-terminate-block node nil)))))))
697 (setf (lvar-reoptimize arg) nil)))
698 (check-important-result node info)
699 (let ((fun (fun-info-destroyed-constant-args info)))
701 ;; If somebody is really sure that they want to modify
702 ;; constants, let them.
703 (policy node (> check-constant-modification 0)))
704 (let ((destroyed-constant-args (funcall fun args)))
705 (when destroyed-constant-args
706 (let ((*compiler-error-context* node))
707 (warn 'constant-modified
708 :fun-name (lvar-fun-name
709 (basic-combination-fun node)))
710 (setf (basic-combination-kind node) :error)
711 (return-from ir1-optimize-combination))))))
713 (let ((attr (fun-info-attributes info)))
714 (when (and (ir1-attributep attr foldable)
715 ;; KLUDGE: The next test could be made more sensitive,
716 ;; only suppressing constant-folding of functions with
717 ;; CALL attributes when they're actually passed
718 ;; function arguments. -- WHN 19990918
719 (not (ir1-attributep attr call))
720 (every #'constant-lvar-p args)
722 (constant-fold-call node)
723 (return-from ir1-optimize-combination)))
725 (let ((fun (fun-info-derive-type info)))
727 (let ((res (funcall fun node)))
729 (derive-node-type node (coerce-to-values res))
730 (maybe-terminate-block node nil)))))
732 (let ((fun (fun-info-optimizer info)))
733 (unless (and fun (funcall fun node))
734 ;; First give the VM a peek at the call
735 (multiple-value-bind (style transform)
736 (combination-implementation-style node)
739 ;; The VM knows how to handle this.
742 ;; The VM mostly knows how to handle this. We need
743 ;; to massage the call slightly, though.
744 (transform-call node transform (combination-fun-source-name node)))
746 ;; Let transforms have a crack at it.
747 (dolist (x (fun-info-transforms info))
749 (when *show-transforms-p*
750 (let* ((lvar (basic-combination-fun node))
751 (fname (lvar-fun-name lvar t)))
752 (/show "trying transform" x (transform-function x) "for" fname)))
753 (unless (ir1-transform node x)
755 (when *show-transforms-p*
756 (/show "quitting because IR1-TRANSFORM result was NIL"))
761 ;;; If NODE doesn't return (i.e. return type is NIL), then terminate
762 ;;; the block there, and link it to the component tail.
764 ;;; Except when called during IR1 convertion, we delete the
765 ;;; continuation if it has no other uses. (If it does have other uses,
768 ;;; Termination on the basis of a continuation type is
770 ;;; -- The continuation is deleted (hence the assertion is spurious), or
771 ;;; -- We are in IR1 conversion (where THE assertions are subject to
772 ;;; weakening.) FIXME: Now THE assertions are not weakened, but new
773 ;;; uses can(?) be added later. -- APD, 2003-07-17
775 ;;; Why do we need to consider LVAR type? -- APD, 2003-07-30
776 (defun maybe-terminate-block (node ir1-converting-not-optimizing-p)
777 (declare (type (or basic-combination cast ref) node))
778 (let* ((block (node-block node))
779 (lvar (node-lvar node))
780 (ctran (node-next node))
781 (tail (component-tail (block-component block)))
782 (succ (first (block-succ block))))
783 (declare (ignore lvar))
784 (unless (or (and (eq node (block-last block)) (eq succ tail))
785 (block-delete-p block))
786 (when (eq (node-derived-type node) *empty-type*)
787 (cond (ir1-converting-not-optimizing-p
790 (aver (eq (block-last block) node)))
792 (setf (block-last block) node)
793 (setf (ctran-use ctran) nil)
794 (setf (ctran-kind ctran) :unused)
795 (setf (ctran-block ctran) nil)
796 (setf (node-next node) nil)
797 (link-blocks block (ctran-starts-block ctran)))))
799 (node-ends-block node)))
801 (let ((succ (first (block-succ block))))
802 (unlink-blocks block succ)
803 (setf (component-reanalyze (block-component block)) t)
804 (aver (not (block-succ block)))
805 (link-blocks block tail)
806 (cond (ir1-converting-not-optimizing-p
807 (%delete-lvar-use node))
808 (t (delete-lvar-use node)
809 (when (null (block-pred succ))
810 (mark-for-deletion succ)))))
813 ;;; This is called both by IR1 conversion and IR1 optimization when
814 ;;; they have verified the type signature for the call, and are
815 ;;; wondering if something should be done to special-case the call. If
816 ;;; CALL is a call to a global function, then see whether it defined
818 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
819 ;;; the expansion and change the call to call it. Expansion is
820 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
821 ;;; true, we never expand, since this function has already been
822 ;;; converted. Local call analysis will duplicate the definition
823 ;;; if necessary. We claim that the parent form is LABELS for
824 ;;; context declarations, since we don't want it to be considered
825 ;;; a real global function.
826 ;;; -- If it is a known function, mark it as such by setting the KIND.
828 ;;; We return the leaf referenced (NIL if not a leaf) and the
829 ;;; FUN-INFO assigned.
830 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
831 (declare (type combination call))
832 (let* ((ref (lvar-uses (basic-combination-fun call)))
833 (leaf (when (ref-p ref) (ref-leaf ref)))
834 (inlinep (if (defined-fun-p leaf)
835 (defined-fun-inlinep leaf)
838 ((eq inlinep :notinline)
839 (let ((info (info :function :info (leaf-source-name leaf))))
841 (setf (basic-combination-fun-info call) info))
843 ((not (and (global-var-p leaf)
844 (eq (global-var-kind leaf) :global-function)))
849 ((nil :maybe-inline) (policy call (zerop space))))
851 (defined-fun-inline-expansion leaf)
852 (inline-expansion-ok call))
853 ;; Inline: if the function has already been converted at another call
854 ;; site in this component, we point this REF to the functional. If not,
855 ;; we convert the expansion.
857 ;; For :INLINE case local call analysis will copy the expansion later,
858 ;; but for :MAYBE-INLINE and NIL cases we only get one copy of the
859 ;; expansion per component.
861 ;; FIXME: We also convert in :INLINE & FUNCTIONAL-KIND case below. What
864 (let* ((name (leaf-source-name leaf))
865 (res (ir1-convert-inline-expansion
867 (defined-fun-inline-expansion leaf)
870 (info :function :info name))))
871 ;; allow backward references to this function from
872 ;; following top level forms
873 (setf (defined-fun-functional leaf) res)
874 (change-ref-leaf ref res))))
875 (let ((fun (defined-fun-functional leaf)))
877 (and (eq inlinep :inline) (functional-kind fun)))
879 (if ir1-converting-not-optimizing-p
881 (with-ir1-environment-from-node call
883 (locall-analyze-component *current-component*)))
884 ;; If we've already converted, change ref to the converted functional.
885 (change-ref-leaf ref fun))))
886 (values (ref-leaf ref) nil))
888 (let ((info (info :function :info (leaf-source-name leaf))))
892 (setf (basic-combination-kind call) :known)
893 (setf (basic-combination-fun-info call) info)))
894 (values leaf nil)))))))
896 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
897 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
898 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
899 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
900 ;;; syntax check, arg/result type processing, but still call
901 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
902 ;;; and that checking is done by local call analysis.
903 (defun validate-call-type (call type defined-type ir1-converting-not-optimizing-p)
904 (declare (type combination call) (type ctype type))
905 (cond ((not (fun-type-p type))
906 (aver (multiple-value-bind (val win)
907 (csubtypep type (specifier-type 'function))
909 ;; In the commonish case where the function has been defined
910 ;; in another file, we only get FUNCTION for the type; but we
911 ;; can check whether the current call is valid for the
912 ;; existing definition, even if only to STYLE-WARN about it.
914 (valid-fun-use call defined-type
915 :argument-test #'always-subtypep
917 :lossage-fun #'compiler-style-warn
918 :unwinnage-fun #'compiler-notify))
919 (recognize-known-call call ir1-converting-not-optimizing-p))
920 ((valid-fun-use call type
921 :argument-test #'always-subtypep
923 ;; KLUDGE: Common Lisp is such a dynamic
924 ;; language that all we can do here in
925 ;; general is issue a STYLE-WARNING. It
926 ;; would be nice to issue a full WARNING
927 ;; in the special case of of type
928 ;; mismatches within a compilation unit
929 ;; (as in section 3.2.2.3 of the spec)
930 ;; but at least as of sbcl-0.6.11, we
931 ;; don't keep track of whether the
932 ;; mismatched data came from the same
933 ;; compilation unit, so we can't do that.
936 ;; FIXME: Actually, I think we could
937 ;; issue a full WARNING if the call
938 ;; violates a DECLAIM FTYPE.
939 :lossage-fun #'compiler-style-warn
940 :unwinnage-fun #'compiler-notify)
941 (assert-call-type call type)
942 (maybe-terminate-block call ir1-converting-not-optimizing-p)
943 (recognize-known-call call ir1-converting-not-optimizing-p))
945 (setf (combination-kind call) :error)
948 ;;; This is called by IR1-OPTIMIZE when the function for a call has
949 ;;; changed. If the call is local, we try to LET-convert it, and
950 ;;; derive the result type. If it is a :FULL call, we validate it
951 ;;; against the type, which recognizes known calls, does inline
952 ;;; expansion, etc. If a call to a predicate in a non-conditional
953 ;;; position or to a function with a source transform, then we
954 ;;; reconvert the form to give IR1 another chance.
955 (defun propagate-fun-change (call)
956 (declare (type combination call))
957 (let ((*compiler-error-context* call)
958 (fun-lvar (basic-combination-fun call)))
959 (setf (lvar-reoptimize fun-lvar) nil)
960 (case (combination-kind call)
962 (let ((fun (combination-lambda call)))
963 (maybe-let-convert fun)
964 (unless (member (functional-kind fun) '(:let :assignment :deleted))
965 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
967 (multiple-value-bind (leaf info)
968 (validate-call-type call (lvar-type fun-lvar) nil nil)
969 (cond ((functional-p leaf)
970 (convert-call-if-possible
971 (lvar-uses (basic-combination-fun call))
974 ((and (global-var-p leaf)
975 (eq (global-var-kind leaf) :global-function)
976 (leaf-has-source-name-p leaf)
977 (or (info :function :source-transform (leaf-source-name leaf))
979 (ir1-attributep (fun-info-attributes info)
981 (let ((lvar (node-lvar call)))
982 (and lvar (not (if-p (lvar-dest lvar))))))))
983 (let ((name (leaf-source-name leaf))
984 (dummies (make-gensym-list
985 (length (combination-args call)))))
988 (,@(if (symbolp name)
992 (leaf-source-name leaf)))))))))
995 ;;;; known function optimization
997 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
998 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
999 ;;; replace it, otherwise add a new one.
1000 (defun record-optimization-failure (node transform args)
1001 (declare (type combination node) (type transform transform)
1002 (type (or fun-type list) args))
1003 (let* ((table (component-failed-optimizations *component-being-compiled*))
1004 (found (assoc transform (gethash node table))))
1006 (setf (cdr found) args)
1007 (push (cons transform args) (gethash node table))))
1010 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
1011 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
1012 ;;; doing the transform for some reason and FLAME is true, then we
1013 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
1014 ;;; finalize to pick up. We return true if the transform failed, and
1015 ;;; thus further transformation should be attempted. We return false
1016 ;;; if either the transform succeeded or was aborted.
1017 (defun ir1-transform (node transform)
1018 (declare (type combination node) (type transform transform))
1019 (let* ((type (transform-type transform))
1020 (fun (transform-function transform))
1021 (constrained (fun-type-p type))
1022 (table (component-failed-optimizations *component-being-compiled*))
1023 (flame (if (transform-important transform)
1024 (policy node (>= speed inhibit-warnings))
1025 (policy node (> speed inhibit-warnings))))
1026 (*compiler-error-context* node))
1027 (cond ((or (not constrained)
1028 (valid-fun-use node type))
1029 (multiple-value-bind (severity args)
1030 (catch 'give-up-ir1-transform
1031 (transform-call node
1033 (combination-fun-source-name node))
1037 (remhash node table)
1040 (setf (combination-kind node) :error)
1042 (apply #'warn args))
1043 (remhash node table)
1048 (record-optimization-failure node transform args))
1049 (setf (gethash node table)
1050 (remove transform (gethash node table) :key #'car)))
1053 (remhash node table)
1058 :argument-test #'types-equal-or-intersect
1059 :result-test #'values-types-equal-or-intersect))
1060 (record-optimization-failure node transform type)
1065 ;;; When we don't like an IR1 transform, we throw the severity/reason
1068 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1069 ;;; aborting this attempt to transform the call, but admitting the
1070 ;;; possibility that this or some other transform will later succeed.
1071 ;;; If arguments are supplied, they are format arguments for an
1072 ;;; efficiency note.
1074 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1075 ;;; force a normal call to the function at run time. No further
1076 ;;; optimizations will be attempted.
1078 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1079 ;;; delay the transform on the node until later. REASONS specifies
1080 ;;; when the transform will be later retried. The :OPTIMIZE reason
1081 ;;; causes the transform to be delayed until after the current IR1
1082 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1083 ;;; be delayed until after constraint propagation.
1085 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1086 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1087 ;;; do CASE operations on the various REASON values, it might be a
1088 ;;; good idea to go OO, representing the reasons by objects, using
1089 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1090 ;;; SIGNAL instead of THROW.
1091 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1092 (defun give-up-ir1-transform (&rest args)
1093 (throw 'give-up-ir1-transform (values :failure args)))
1094 (defun abort-ir1-transform (&rest args)
1095 (throw 'give-up-ir1-transform (values :aborted args)))
1096 (defun delay-ir1-transform (node &rest reasons)
1097 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1099 (setf *delayed-ir1-transforms*
1100 (acons node reasons *delayed-ir1-transforms*))
1101 (throw 'give-up-ir1-transform :delayed))
1103 (dolist (reason reasons)
1104 (pushnew reason (cdr assoc)))
1105 (throw 'give-up-ir1-transform :delayed)))))
1107 ;;; Clear any delayed transform with no reasons - these should have
1108 ;;; been tried in the last pass. Then remove the reason from the
1109 ;;; delayed transform reasons, and if any become empty then set
1110 ;;; reoptimize flags for the node. Return true if any transforms are
1112 (defun retry-delayed-ir1-transforms (reason)
1113 (setf *delayed-ir1-transforms*
1114 (remove-if-not #'cdr *delayed-ir1-transforms*))
1115 (let ((reoptimize nil))
1116 (dolist (assoc *delayed-ir1-transforms*)
1117 (let ((reasons (remove reason (cdr assoc))))
1118 (setf (cdr assoc) reasons)
1120 (let ((node (car assoc)))
1121 (unless (node-deleted node)
1123 (setf (node-reoptimize node) t)
1124 (let ((block (node-block node)))
1125 (setf (block-reoptimize block) t)
1126 (reoptimize-component (block-component block) :maybe)))))))
1129 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1130 ;;; environment, and then install it as the function for the call
1131 ;;; NODE. We do local call analysis so that the new function is
1132 ;;; integrated into the control flow.
1134 ;;; We require the original function source name in order to generate
1135 ;;; a meaningful debug name for the lambda we set up. (It'd be
1136 ;;; possible to do this starting from debug names as well as source
1137 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1138 ;;; generality, since source names are always known to our callers.)
1139 (defun transform-call (call res source-name)
1140 (declare (type combination call) (list res))
1141 (aver (and (legal-fun-name-p source-name)
1142 (not (eql source-name '.anonymous.))))
1143 (node-ends-block call)
1144 ;; The internal variables of a transform are not going to be
1145 ;; interesting to the debugger, so there's no sense in
1146 ;; suppressing the substitution of variables with only one use
1147 ;; (the extra variables can slow down constraint propagation).
1149 ;; This needs to be done before the WITH-IR1-ENVIRONMENT-FROM-NODE,
1150 ;; so that it will bind *LEXENV* to the right environment.
1151 (setf (combination-lexenv call)
1152 (make-lexenv :default (combination-lexenv call)
1153 :policy (process-optimize-decl
1155 (preserve-single-use-debug-variables 0))
1157 (combination-lexenv call)))))
1158 (with-ir1-environment-from-node call
1159 (with-component-last-block (*current-component*
1160 (block-next (node-block call)))
1162 (let ((new-fun (ir1-convert-inline-lambda
1164 :debug-name (debug-name 'lambda-inlined source-name)
1166 (ref (lvar-use (combination-fun call))))
1167 (change-ref-leaf ref new-fun)
1168 (setf (combination-kind call) :full)
1169 (locall-analyze-component *current-component*))))
1172 ;;; Replace a call to a foldable function of constant arguments with
1173 ;;; the result of evaluating the form. If there is an error during the
1174 ;;; evaluation, we give a warning and leave the call alone, making the
1175 ;;; call a :ERROR call.
1177 ;;; If there is more than one value, then we transform the call into a
1179 (defun constant-fold-call (call)
1180 (let ((args (mapcar #'lvar-value (combination-args call)))
1181 (fun-name (combination-fun-source-name call)))
1182 (multiple-value-bind (values win)
1183 (careful-call fun-name
1186 ;; Note: CMU CL had COMPILER-WARN here, and that
1187 ;; seems more natural, but it's probably not.
1189 ;; It's especially not while bug 173 exists:
1192 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1194 ;; can cause constant-folding TYPE-ERRORs (in
1195 ;; #'<=) when END can be proved to be NIL, even
1196 ;; though the code is perfectly legal and safe
1197 ;; because a NIL value of END means that the
1198 ;; #'<= will never be executed.
1200 ;; Moreover, even without bug 173,
1201 ;; quite-possibly-valid code like
1202 ;; (COND ((NONINLINED-PREDICATE END)
1203 ;; (UNLESS (<= END SIZE))
1205 ;; (where NONINLINED-PREDICATE is something the
1206 ;; compiler can't do at compile time, but which
1207 ;; turns out to make the #'<= expression
1208 ;; unreachable when END=NIL) could cause errors
1209 ;; when the compiler tries to constant-fold (<=
1212 ;; So, with or without bug 173, it'd be
1213 ;; unnecessarily evil to do a full
1214 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1215 ;; from COMPILE-FILE) for legal code, so we we
1216 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1217 #-sb-xc-host #'compiler-style-warn
1218 ;; On the other hand, for code we control, we
1219 ;; should be able to work around any bug
1220 ;; 173-related problems, and in particular we
1221 ;; want to be alerted to calls to our own
1222 ;; functions which aren't being folded away; a
1223 ;; COMPILER-WARNING is butch enough to stop the
1224 ;; SBCL build itself in its tracks.
1225 #+sb-xc-host #'compiler-warn
1228 (setf (combination-kind call) :error))
1229 ((and (proper-list-of-length-p values 1))
1230 (with-ir1-environment-from-node call
1231 (let* ((lvar (node-lvar call))
1232 (prev (node-prev call))
1233 (intermediate-ctran (make-ctran)))
1234 (%delete-lvar-use call)
1235 (setf (ctran-next prev) nil)
1236 (setf (node-prev call) nil)
1237 (reference-constant prev intermediate-ctran lvar
1239 (link-node-to-previous-ctran call intermediate-ctran)
1240 (reoptimize-lvar lvar)
1241 (flush-combination call))))
1242 (t (let ((dummies (make-gensym-list (length args))))
1246 (declare (ignore ,@dummies))
1247 (values ,@(mapcar (lambda (x) `',x) values)))
1251 ;;;; local call optimization
1253 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1254 ;;; the leaf type is a function type, then just leave it alone, since
1255 ;;; TYPE is never going to be more specific than that (and
1256 ;;; TYPE-INTERSECTION would choke.)
1257 (defun propagate-to-refs (leaf type)
1258 (declare (type leaf leaf) (type ctype type))
1259 (let ((var-type (leaf-type leaf)))
1260 (unless (fun-type-p var-type)
1261 (let ((int (type-approx-intersection2 var-type type)))
1262 (when (type/= int var-type)
1263 (setf (leaf-type leaf) int)
1264 (let ((s-int (make-single-value-type int)))
1265 (dolist (ref (leaf-refs leaf))
1266 (derive-node-type ref s-int)
1267 ;; KLUDGE: LET var substitution
1268 (let* ((lvar (node-lvar ref)))
1269 (when (and lvar (combination-p (lvar-dest lvar)))
1270 (reoptimize-lvar lvar)))))))
1273 ;;; Iteration variable: exactly one SETQ of the form:
1275 ;;; (let ((var initial))
1277 ;;; (setq var (+ var step))
1279 (defun maybe-infer-iteration-var-type (var initial-type)
1280 (binding* ((sets (lambda-var-sets var) :exit-if-null)
1282 (() (null (rest sets)) :exit-if-null)
1283 (set-use (principal-lvar-use (set-value set)))
1284 (() (and (combination-p set-use)
1285 (eq (combination-kind set-use) :known)
1286 (fun-info-p (combination-fun-info set-use))
1287 (not (node-to-be-deleted-p set-use))
1288 (or (eq (combination-fun-source-name set-use) '+)
1289 (eq (combination-fun-source-name set-use) '-)))
1291 (minusp (eq (combination-fun-source-name set-use) '-))
1292 (+-args (basic-combination-args set-use))
1293 (() (and (proper-list-of-length-p +-args 2 2)
1294 (let ((first (principal-lvar-use
1297 (eq (ref-leaf first) var))))
1299 (step-type (lvar-type (second +-args)))
1300 (set-type (lvar-type (set-value set))))
1301 (when (and (numeric-type-p initial-type)
1302 (numeric-type-p step-type)
1303 (or (numeric-type-equal initial-type step-type)
1304 ;; Detect cases like (LOOP FOR 1.0 to 5.0 ...), where
1305 ;; the initial and the step are of different types,
1306 ;; and the step is less contagious.
1307 (numeric-type-equal initial-type
1308 (numeric-contagion initial-type
1310 (labels ((leftmost (x y cmp cmp=)
1311 (cond ((eq x nil) nil)
1314 (let ((x1 (first x)))
1316 (let ((y1 (first y)))
1317 (if (funcall cmp x1 y1) x y)))
1319 (if (funcall cmp x1 y) x y)))))
1321 (let ((y1 (first y)))
1322 (if (funcall cmp= x y1) x y)))
1323 (t (if (funcall cmp x y) x y))))
1324 (max* (x y) (leftmost x y #'> #'>=))
1325 (min* (x y) (leftmost x y #'< #'<=)))
1326 (multiple-value-bind (low high)
1327 (let ((step-type-non-negative (csubtypep step-type (specifier-type
1329 (step-type-non-positive (csubtypep step-type (specifier-type
1331 (cond ((or (and step-type-non-negative (not minusp))
1332 (and step-type-non-positive minusp))
1333 (values (numeric-type-low initial-type)
1334 (when (and (numeric-type-p set-type)
1335 (numeric-type-equal set-type initial-type))
1336 (max* (numeric-type-high initial-type)
1337 (numeric-type-high set-type)))))
1338 ((or (and step-type-non-positive (not minusp))
1339 (and step-type-non-negative minusp))
1340 (values (when (and (numeric-type-p set-type)
1341 (numeric-type-equal set-type initial-type))
1342 (min* (numeric-type-low initial-type)
1343 (numeric-type-low set-type)))
1344 (numeric-type-high initial-type)))
1347 (modified-numeric-type initial-type
1350 :enumerable nil))))))
1351 (deftransform + ((x y) * * :result result)
1352 "check for iteration variable reoptimization"
1353 (let ((dest (principal-lvar-end result))
1354 (use (principal-lvar-use x)))
1355 (when (and (ref-p use)
1359 (reoptimize-lvar (set-value dest))))
1360 (give-up-ir1-transform))
1362 ;;; Figure out the type of a LET variable that has sets. We compute
1363 ;;; the union of the INITIAL-TYPE and the types of all the set
1364 ;;; values and to a PROPAGATE-TO-REFS with this type.
1365 (defun propagate-from-sets (var initial-type)
1366 (let ((changes (not (csubtypep (lambda-var-last-initial-type var) initial-type)))
1368 (dolist (set (lambda-var-sets var))
1369 (let ((type (lvar-type (set-value set))))
1371 (when (node-reoptimize set)
1372 (let ((old-type (node-derived-type set)))
1373 (unless (values-subtypep old-type type)
1374 (derive-node-type set (make-single-value-type type))
1376 (setf (node-reoptimize set) nil))))
1378 (setf (lambda-var-last-initial-type var) initial-type)
1379 (let ((res-type (or (maybe-infer-iteration-var-type var initial-type)
1380 (apply #'type-union initial-type types))))
1381 (propagate-to-refs var res-type))))
1384 ;;; If a LET variable, find the initial value's type and do
1385 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1387 (defun ir1-optimize-set (node)
1388 (declare (type cset node))
1389 (let ((var (set-var node)))
1390 (when (and (lambda-var-p var) (leaf-refs var))
1391 (let ((home (lambda-var-home var)))
1392 (when (eq (functional-kind home) :let)
1393 (let* ((initial-value (let-var-initial-value var))
1394 (initial-type (lvar-type initial-value)))
1395 (setf (lvar-reoptimize initial-value) nil)
1396 (propagate-from-sets var initial-type))))))
1397 (derive-node-type node (make-single-value-type
1398 (lvar-type (set-value node))))
1399 (setf (node-reoptimize node) nil)
1402 ;;; Return true if the value of REF will always be the same (and is
1403 ;;; thus legal to substitute.)
1404 (defun constant-reference-p (ref)
1405 (declare (type ref ref))
1406 (let ((leaf (ref-leaf ref)))
1408 ((or constant functional) t)
1410 (null (lambda-var-sets leaf)))
1412 (not (eq (defined-fun-inlinep leaf) :notinline)))
1414 (case (global-var-kind leaf)
1416 (let ((name (leaf-source-name leaf)))
1418 (eq (symbol-package (fun-name-block-name name))
1420 (info :function :info name)))))))))
1422 ;;; If we have a non-set LET var with a single use, then (if possible)
1423 ;;; replace the variable reference's LVAR with the arg lvar.
1425 ;;; We change the REF to be a reference to NIL with unused value, and
1426 ;;; let it be flushed as dead code. A side effect of this substitution
1427 ;;; is to delete the variable.
1428 (defun substitute-single-use-lvar (arg var)
1429 (declare (type lvar arg) (type lambda-var var))
1430 (binding* ((ref (first (leaf-refs var)))
1431 (lvar (node-lvar ref) :exit-if-null)
1432 (dest (lvar-dest lvar)))
1434 ;; Think about (LET ((A ...)) (IF ... A ...)): two
1435 ;; LVAR-USEs should not be met on one path. Another problem
1436 ;; is with dynamic-extent.
1437 (eq (lvar-uses lvar) ref)
1438 (not (block-delete-p (node-block ref)))
1440 ;; we should not change lifetime of unknown values lvars
1442 (and (type-single-value-p (lvar-derived-type arg))
1443 (multiple-value-bind (pdest pprev)
1444 (principal-lvar-end lvar)
1445 (declare (ignore pdest))
1446 (lvar-single-value-p pprev))))
1448 (or (eq (basic-combination-fun dest) lvar)
1449 (and (eq (basic-combination-kind dest) :local)
1450 (type-single-value-p (lvar-derived-type arg)))))
1452 ;; While CRETURN and EXIT nodes may be known-values,
1453 ;; they have their own complications, such as
1454 ;; substitution into CRETURN may create new tail calls.
1457 (aver (lvar-single-value-p lvar))
1459 (eq (node-home-lambda ref)
1460 (lambda-home (lambda-var-home var))))
1461 (let ((ref-type (single-value-type (node-derived-type ref))))
1462 (cond ((csubtypep (single-value-type (lvar-type arg)) ref-type)
1463 (substitute-lvar-uses lvar arg
1464 ;; Really it is (EQ (LVAR-USES LVAR) REF):
1466 (delete-lvar-use ref))
1468 (let* ((value (make-lvar))
1469 (cast (insert-cast-before ref value ref-type
1470 ;; KLUDGE: it should be (TYPE-CHECK 0)
1472 (setf (cast-type-to-check cast) *wild-type*)
1473 (substitute-lvar-uses value arg
1476 (%delete-lvar-use ref)
1477 (add-lvar-use cast lvar)))))
1478 (setf (node-derived-type ref) *wild-type*)
1479 (change-ref-leaf ref (find-constant nil))
1482 (reoptimize-lvar lvar)
1485 ;;; Delete a LET, removing the call and bind nodes, and warning about
1486 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1487 ;;; along right away and delete the REF and then the lambda, since we
1488 ;;; flush the FUN lvar.
1489 (defun delete-let (clambda)
1490 (declare (type clambda clambda))
1491 (aver (functional-letlike-p clambda))
1492 (note-unreferenced-vars clambda)
1493 (let ((call (let-combination clambda)))
1494 (flush-dest (basic-combination-fun call))
1496 (unlink-node (lambda-bind clambda))
1497 (setf (lambda-bind clambda) nil))
1498 (setf (functional-kind clambda) :zombie)
1499 (let ((home (lambda-home clambda)))
1500 (setf (lambda-lets home) (delete clambda (lambda-lets home))))
1503 ;;; This function is called when one of the arguments to a LET
1504 ;;; changes. We look at each changed argument. If the corresponding
1505 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1506 ;;; consider substituting for the variable, and also propagate
1507 ;;; derived-type information for the arg to all the VAR's refs.
1509 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1510 ;;; subtype of the argument's leaf type. This prevents type checking
1511 ;;; from being defeated, and also ensures that the best representation
1512 ;;; for the variable can be used.
1514 ;;; Substitution of individual references is inhibited if the
1515 ;;; reference is in a different component from the home. This can only
1516 ;;; happen with closures over top level lambda vars. In such cases,
1517 ;;; the references may have already been compiled, and thus can't be
1518 ;;; retroactively modified.
1520 ;;; If all of the variables are deleted (have no references) when we
1521 ;;; are done, then we delete the LET.
1523 ;;; Note that we are responsible for clearing the LVAR-REOPTIMIZE
1525 (defun propagate-let-args (call fun)
1526 (declare (type combination call) (type clambda fun))
1527 (loop for arg in (combination-args call)
1528 and var in (lambda-vars fun) do
1529 (when (and arg (lvar-reoptimize arg))
1530 (setf (lvar-reoptimize arg) nil)
1532 ((lambda-var-sets var)
1533 (propagate-from-sets var (lvar-type arg)))
1534 ((let ((use (lvar-uses arg)))
1536 (let ((leaf (ref-leaf use)))
1537 (when (and (constant-reference-p use)
1538 (csubtypep (leaf-type leaf)
1539 ;; (NODE-DERIVED-TYPE USE) would
1540 ;; be better -- APD, 2003-05-15
1542 (propagate-to-refs var (lvar-type arg))
1543 (let ((use-component (node-component use)))
1544 (prog1 (substitute-leaf-if
1546 (cond ((eq (node-component ref) use-component)
1549 (aver (lambda-toplevelish-p (lambda-home fun)))
1553 ((and (null (rest (leaf-refs var)))
1554 ;; Don't substitute single-ref variables on high-debug /
1555 ;; low speed, to improve the debugging experience.
1556 (policy call (< preserve-single-use-debug-variables 3))
1557 (substitute-single-use-lvar arg var)))
1559 (propagate-to-refs var (lvar-type arg))))))
1561 (when (every #'not (combination-args call))
1566 ;;; This function is called when one of the args to a non-LET local
1567 ;;; call changes. For each changed argument corresponding to an unset
1568 ;;; variable, we compute the union of the types across all calls and
1569 ;;; propagate this type information to the var's refs.
1571 ;;; If the function has an XEP, then we don't do anything, since we
1572 ;;; won't discover anything.
1574 ;;; We can clear the LVAR-REOPTIMIZE flags for arguments in all calls
1575 ;;; corresponding to changed arguments in CALL, since the only use in
1576 ;;; IR1 optimization of the REOPTIMIZE flag for local call args is
1578 (defun propagate-local-call-args (call fun)
1579 (declare (type combination call) (type clambda fun))
1580 (unless (or (functional-entry-fun fun)
1581 (lambda-optional-dispatch fun))
1582 (let* ((vars (lambda-vars fun))
1583 (union (mapcar (lambda (arg var)
1585 (lvar-reoptimize arg)
1586 (null (basic-var-sets var)))
1588 (basic-combination-args call)
1590 (this-ref (lvar-use (basic-combination-fun call))))
1592 (dolist (arg (basic-combination-args call))
1594 (setf (lvar-reoptimize arg) nil)))
1596 (dolist (ref (leaf-refs fun))
1597 (let ((dest (node-dest ref)))
1598 (unless (or (eq ref this-ref) (not dest))
1600 (mapcar (lambda (this-arg old)
1602 (setf (lvar-reoptimize this-arg) nil)
1603 (type-union (lvar-type this-arg) old)))
1604 (basic-combination-args dest)
1607 (loop for var in vars
1609 when type do (propagate-to-refs var type))))
1613 ;;;; multiple values optimization
1615 ;;; Do stuff to notice a change to a MV combination node. There are
1616 ;;; two main branches here:
1617 ;;; -- If the call is local, then it is already a MV let, or should
1618 ;;; become one. Note that although all :LOCAL MV calls must eventually
1619 ;;; be converted to :MV-LETs, there can be a window when the call
1620 ;;; is local, but has not been LET converted yet. This is because
1621 ;;; the entry-point lambdas may have stray references (in other
1622 ;;; entry points) that have not been deleted yet.
1623 ;;; -- The call is full. This case is somewhat similar to the non-MV
1624 ;;; combination optimization: we propagate return type information and
1625 ;;; notice non-returning calls. We also have an optimization
1626 ;;; which tries to convert MV-CALLs into MV-binds.
1627 (defun ir1-optimize-mv-combination (node)
1628 (ecase (basic-combination-kind node)
1630 (let ((fun-lvar (basic-combination-fun node)))
1631 (when (lvar-reoptimize fun-lvar)
1632 (setf (lvar-reoptimize fun-lvar) nil)
1633 (maybe-let-convert (combination-lambda node))))
1634 (setf (lvar-reoptimize (first (basic-combination-args node))) nil)
1635 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1636 (unless (convert-mv-bind-to-let node)
1637 (ir1-optimize-mv-bind node))))
1639 (let* ((fun (basic-combination-fun node))
1640 (fun-changed (lvar-reoptimize fun))
1641 (args (basic-combination-args node)))
1643 (setf (lvar-reoptimize fun) nil)
1644 (let ((type (lvar-type fun)))
1645 (when (fun-type-p type)
1646 (derive-node-type node (fun-type-returns type))))
1647 (maybe-terminate-block node nil)
1648 (let ((use (lvar-uses fun)))
1649 (when (and (ref-p use) (functional-p (ref-leaf use)))
1650 (convert-call-if-possible use node)
1651 (when (eq (basic-combination-kind node) :local)
1652 (maybe-let-convert (ref-leaf use))))))
1653 (unless (or (eq (basic-combination-kind node) :local)
1654 (eq (lvar-fun-name fun) '%throw))
1655 (ir1-optimize-mv-call node))
1657 (setf (lvar-reoptimize arg) nil))))
1661 ;;; Propagate derived type info from the values lvar to the vars.
1662 (defun ir1-optimize-mv-bind (node)
1663 (declare (type mv-combination node))
1664 (let* ((arg (first (basic-combination-args node)))
1665 (vars (lambda-vars (combination-lambda node)))
1666 (n-vars (length vars))
1667 (types (values-type-in (lvar-derived-type arg)
1669 (loop for var in vars
1671 do (if (basic-var-sets var)
1672 (propagate-from-sets var type)
1673 (propagate-to-refs var type)))
1674 (setf (lvar-reoptimize arg) nil))
1677 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1679 ;;; -- The call has only one argument, and
1680 ;;; -- The function has a known fixed number of arguments, or
1681 ;;; -- The argument yields a known fixed number of values.
1683 ;;; What we do is change the function in the MV-CALL to be a lambda
1684 ;;; that "looks like an MV bind", which allows
1685 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1686 ;;; converted (the next time around.) This new lambda just calls the
1687 ;;; actual function with the MV-BIND variables as arguments. Note that
1688 ;;; this new MV bind is not let-converted immediately, as there are
1689 ;;; going to be stray references from the entry-point functions until
1690 ;;; they get deleted.
1692 ;;; In order to avoid loss of argument count checking, we only do the
1693 ;;; transformation according to a known number of expected argument if
1694 ;;; safety is unimportant. We can always convert if we know the number
1695 ;;; of actual values, since the normal call that we build will still
1696 ;;; do any appropriate argument count checking.
1698 ;;; We only attempt the transformation if the called function is a
1699 ;;; constant reference. This allows us to just splice the leaf into
1700 ;;; the new function, instead of trying to somehow bind the function
1701 ;;; expression. The leaf must be constant because we are evaluating it
1702 ;;; again in a different place. This also has the effect of squelching
1703 ;;; multiple warnings when there is an argument count error.
1704 (defun ir1-optimize-mv-call (node)
1705 (let ((fun (basic-combination-fun node))
1706 (*compiler-error-context* node)
1707 (ref (lvar-uses (basic-combination-fun node)))
1708 (args (basic-combination-args node)))
1710 (unless (and (ref-p ref) (constant-reference-p ref)
1712 (return-from ir1-optimize-mv-call))
1714 (multiple-value-bind (min max)
1715 (fun-type-nargs (lvar-type fun))
1717 (multiple-value-bind (types nvals)
1718 (values-types (lvar-derived-type (first args)))
1719 (declare (ignore types))
1720 (if (eq nvals :unknown) nil nvals))))
1723 (when (and min (< total-nvals min))
1725 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1728 (setf (basic-combination-kind node) :error)
1729 (return-from ir1-optimize-mv-call))
1730 (when (and max (> total-nvals max))
1732 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1735 (setf (basic-combination-kind node) :error)
1736 (return-from ir1-optimize-mv-call)))
1738 (let ((count (cond (total-nvals)
1739 ((and (policy node (zerop verify-arg-count))
1744 (with-ir1-environment-from-node node
1745 (let* ((dums (make-gensym-list count))
1747 (leaf (ref-leaf ref))
1748 (fun (ir1-convert-lambda
1749 `(lambda (&optional ,@dums &rest ,ignore)
1750 (declare (ignore ,ignore))
1751 (%funcall ,leaf ,@dums))
1752 :source-name (leaf-%source-name leaf)
1753 :debug-name (leaf-%debug-name leaf))))
1754 (change-ref-leaf ref fun)
1755 (aver (eq (basic-combination-kind node) :full))
1756 (locall-analyze-component *current-component*)
1757 (aver (eq (basic-combination-kind node) :local)))))))))
1761 ;;; (multiple-value-bind
1770 ;;; What we actually do is convert the VALUES combination into a
1771 ;;; normal LET combination calling the original :MV-LET lambda. If
1772 ;;; there are extra args to VALUES, discard the corresponding
1773 ;;; lvars. If there are insufficient args, insert references to NIL.
1774 (defun convert-mv-bind-to-let (call)
1775 (declare (type mv-combination call))
1776 (let* ((arg (first (basic-combination-args call)))
1777 (use (lvar-uses arg)))
1778 (when (and (combination-p use)
1779 (eq (lvar-fun-name (combination-fun use))
1781 (let* ((fun (combination-lambda call))
1782 (vars (lambda-vars fun))
1783 (vals (combination-args use))
1784 (nvars (length vars))
1785 (nvals (length vals)))
1786 (cond ((> nvals nvars)
1787 (mapc #'flush-dest (subseq vals nvars))
1788 (setq vals (subseq vals 0 nvars)))
1790 (with-ir1-environment-from-node use
1791 (let ((node-prev (node-prev use)))
1792 (setf (node-prev use) nil)
1793 (setf (ctran-next node-prev) nil)
1794 (collect ((res vals))
1795 (loop for count below (- nvars nvals)
1796 for prev = node-prev then ctran
1797 for ctran = (make-ctran)
1798 and lvar = (make-lvar use)
1799 do (reference-constant prev ctran lvar nil)
1801 finally (link-node-to-previous-ctran
1803 (setq vals (res)))))))
1804 (setf (combination-args use) vals)
1805 (flush-dest (combination-fun use))
1806 (let ((fun-lvar (basic-combination-fun call)))
1807 (setf (lvar-dest fun-lvar) use)
1808 (setf (combination-fun use) fun-lvar)
1809 (flush-lvar-externally-checkable-type fun-lvar))
1810 (setf (combination-kind use) :local)
1811 (setf (functional-kind fun) :let)
1812 (flush-dest (first (basic-combination-args call)))
1815 (reoptimize-lvar (first vals)))
1816 (propagate-to-args use fun)
1817 (reoptimize-call use))
1821 ;;; (values-list (list x y z))
1826 ;;; In implementation, this is somewhat similar to
1827 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1828 ;;; args of the VALUES-LIST call, flushing the old argument lvar
1829 ;;; (allowing the LIST to be flushed.)
1831 ;;; FIXME: Thus we lose possible type assertions on (LIST ...).
1832 (defoptimizer (values-list optimizer) ((list) node)
1833 (let ((use (lvar-uses list)))
1834 (when (and (combination-p use)
1835 (eq (lvar-fun-name (combination-fun use))
1838 ;; FIXME: VALUES might not satisfy an assertion on NODE-LVAR.
1839 (change-ref-leaf (lvar-uses (combination-fun node))
1840 (find-free-fun 'values "in a strange place"))
1841 (setf (combination-kind node) :full)
1842 (let ((args (combination-args use)))
1844 (setf (lvar-dest arg) node)
1845 (flush-lvar-externally-checkable-type arg))
1846 (setf (combination-args use) nil)
1848 (setf (combination-args node) args))
1851 ;;; If VALUES appears in a non-MV context, then effectively convert it
1852 ;;; to a PROG1. This allows the computation of the additional values
1853 ;;; to become dead code.
1854 (deftransform values ((&rest vals) * * :node node)
1855 (unless (lvar-single-value-p (node-lvar node))
1856 (give-up-ir1-transform))
1857 (setf (node-derived-type node)
1858 (make-short-values-type (list (single-value-type
1859 (node-derived-type node)))))
1860 (principal-lvar-single-valuify (node-lvar node))
1862 (let ((dummies (make-gensym-list (length (cdr vals)))))
1863 `(lambda (val ,@dummies)
1864 (declare (ignore ,@dummies))
1870 (defun delete-cast (cast)
1871 (declare (type cast cast))
1872 (let ((value (cast-value cast))
1873 (lvar (node-lvar cast)))
1874 (delete-filter cast lvar value)
1876 (reoptimize-lvar lvar)
1877 (when (lvar-single-value-p lvar)
1878 (note-single-valuified-lvar lvar)))
1881 (defun ir1-optimize-cast (cast &optional do-not-optimize)
1882 (declare (type cast cast))
1883 (let ((value (cast-value cast))
1884 (atype (cast-asserted-type cast)))
1885 (when (not do-not-optimize)
1886 (let ((lvar (node-lvar cast)))
1887 (when (values-subtypep (lvar-derived-type value)
1888 (cast-asserted-type cast))
1890 (return-from ir1-optimize-cast t))
1892 (when (and (listp (lvar-uses value))
1894 ;; Pathwise removing of CAST
1895 (let ((ctran (node-next cast))
1896 (dest (lvar-dest lvar))
1899 (do-uses (use value)
1900 (when (and (values-subtypep (node-derived-type use) atype)
1901 (immediately-used-p value use))
1903 (when ctran (ensure-block-start ctran))
1904 (setq next-block (first (block-succ (node-block cast))))
1905 (ensure-block-start (node-prev cast))
1906 (reoptimize-lvar lvar)
1907 (setf (lvar-%derived-type value) nil))
1908 (%delete-lvar-use use)
1909 (add-lvar-use use lvar)
1910 (unlink-blocks (node-block use) (node-block cast))
1911 (link-blocks (node-block use) next-block)
1912 (when (and (return-p dest)
1913 (basic-combination-p use)
1914 (eq (basic-combination-kind use) :local))
1916 (dolist (use (merges))
1917 (merge-tail-sets use)))))))
1919 (let* ((value-type (lvar-derived-type value))
1920 (int (values-type-intersection value-type atype)))
1921 (derive-node-type cast int)
1922 (when (eq int *empty-type*)
1923 (unless (eq value-type *empty-type*)
1925 ;; FIXME: Do it in one step.
1928 (if (cast-single-value-p cast)
1930 `(multiple-value-call #'list 'dummy)))
1933 ;; FIXME: Derived type.
1934 `(%compile-time-type-error 'dummy
1935 ',(type-specifier atype)
1936 ',(type-specifier value-type)))
1937 ;; KLUDGE: FILTER-LVAR does not work for non-returning
1938 ;; functions, so we declare the return type of
1939 ;; %COMPILE-TIME-TYPE-ERROR to be * and derive the real type
1941 (setq value (cast-value cast))
1942 (derive-node-type (lvar-uses value) *empty-type*)
1943 (maybe-terminate-block (lvar-uses value) nil)
1944 ;; FIXME: Is it necessary?
1945 (aver (null (block-pred (node-block cast))))
1946 (delete-block-lazily (node-block cast))
1947 (return-from ir1-optimize-cast)))
1948 (when (eq (node-derived-type cast) *empty-type*)
1949 (maybe-terminate-block cast nil))
1951 (when (and (cast-%type-check cast)
1952 (values-subtypep value-type
1953 (cast-type-to-check cast)))
1954 (setf (cast-%type-check cast) nil))))
1956 (unless do-not-optimize
1957 (setf (node-reoptimize cast) nil)))
1959 (deftransform make-symbol ((string) (simple-string))
1960 `(%make-symbol string))