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 ((null current) res)))
62 (node-derived-type (lvar-uses lvar))))))
64 ;;; Return the derived type for LVAR's first value. This is guaranteed
65 ;;; not to be a VALUES or FUNCTION type.
66 (declaim (ftype (sfunction (lvar) ctype) lvar-type))
67 (defun lvar-type (lvar)
68 (single-value-type (lvar-derived-type lvar)))
70 ;;; If LVAR is an argument of a function, return a type which the
71 ;;; function checks LVAR for.
72 #!-sb-fluid (declaim (inline lvar-externally-checkable-type))
73 (defun lvar-externally-checkable-type (lvar)
74 (or (lvar-%externally-checkable-type lvar)
75 (%lvar-%externally-checkable-type lvar)))
76 (defun %lvar-%externally-checkable-type (lvar)
77 (declare (type lvar lvar))
78 (let ((dest (lvar-dest lvar)))
79 (if (not (and dest (combination-p dest)))
80 ;; TODO: MV-COMBINATION
81 (setf (lvar-%externally-checkable-type lvar) *wild-type*)
82 (let* ((fun (combination-fun dest))
83 (args (combination-args dest))
84 (fun-type (lvar-type fun)))
85 (setf (lvar-%externally-checkable-type fun) *wild-type*)
86 (if (or (not (call-full-like-p dest))
87 (not (fun-type-p fun-type))
88 ;; FUN-TYPE might be (AND FUNCTION (SATISFIES ...)).
89 (fun-type-wild-args fun-type))
92 (setf (lvar-%externally-checkable-type arg)
94 (map-combination-args-and-types
96 (setf (lvar-%externally-checkable-type arg)
97 (acond ((lvar-%externally-checkable-type arg)
98 (values-type-intersection
99 it (coerce-to-values type)))
100 (t (coerce-to-values type)))))
102 (lvar-%externally-checkable-type lvar))
103 #!-sb-fluid(declaim (inline flush-lvar-externally-checkable-type))
104 (defun flush-lvar-externally-checkable-type (lvar)
105 (declare (type lvar lvar))
106 (setf (lvar-%externally-checkable-type lvar) nil))
108 ;;;; interface routines used by optimizers
110 (declaim (inline reoptimize-component))
111 (defun reoptimize-component (component kind)
112 (declare (type component component)
113 (type (member nil :maybe t) kind))
115 (unless (eq (component-reoptimize component) t)
116 (setf (component-reoptimize component) kind)))
118 ;;; This function is called by optimizers to indicate that something
119 ;;; interesting has happened to the value of LVAR. Optimizers must
120 ;;; make sure that they don't call for reoptimization when nothing has
121 ;;; happened, since optimization will fail to terminate.
123 ;;; We clear any cached type for the lvar and set the reoptimize flags
124 ;;; on everything in sight.
125 (defun reoptimize-lvar (lvar)
126 (declare (type (or lvar null) lvar))
128 (setf (lvar-%derived-type lvar) nil)
129 (let ((dest (lvar-dest lvar)))
131 (setf (lvar-reoptimize lvar) t)
132 (setf (node-reoptimize dest) t)
133 (binding* (;; Since this may be called during IR1 conversion,
134 ;; PREV may be missing.
135 (prev (node-prev dest) :exit-if-null)
136 (block (ctran-block prev))
137 (component (block-component block)))
138 (when (typep dest 'cif)
139 (setf (block-test-modified block) t))
140 (setf (block-reoptimize block) t)
141 (reoptimize-component component :maybe))))
143 (setf (block-type-check (node-block node)) t)))
146 (defun reoptimize-lvar-uses (lvar)
147 (declare (type lvar lvar))
149 (setf (node-reoptimize use) t)
150 (setf (block-reoptimize (node-block use)) t)
151 (reoptimize-component (node-component use) :maybe)))
153 ;;; Annotate NODE to indicate that its result has been proven to be
154 ;;; TYPEP to RTYPE. After IR1 conversion has happened, this is the
155 ;;; only correct way to supply information discovered about a node's
156 ;;; type. If you screw with the NODE-DERIVED-TYPE directly, then
157 ;;; information may be lost and reoptimization may not happen.
159 ;;; What we do is intersect RTYPE with NODE's DERIVED-TYPE. If the
160 ;;; intersection is different from the old type, then we do a
161 ;;; REOPTIMIZE-LVAR on the NODE-LVAR.
162 (defun derive-node-type (node rtype)
163 (declare (type valued-node node) (type ctype rtype))
164 (let ((node-type (node-derived-type node)))
165 (unless (eq node-type rtype)
166 (let ((int (values-type-intersection node-type rtype))
167 (lvar (node-lvar node)))
168 (when (type/= node-type int)
169 (when (and *check-consistency*
170 (eq int *empty-type*)
171 (not (eq rtype *empty-type*)))
172 (let ((*compiler-error-context* node))
174 "New inferred type ~S conflicts with old type:~
175 ~% ~S~%*** possible internal error? Please report this."
176 (type-specifier rtype) (type-specifier node-type))))
177 (setf (node-derived-type node) int)
178 ;; If the new type consists of only one object, replace the
179 ;; node with a constant reference.
180 (when (and (ref-p node)
181 (lambda-var-p (ref-leaf node)))
182 (let ((type (single-value-type int)))
183 (when (and (member-type-p type)
184 (null (rest (member-type-members type))))
185 (change-ref-leaf node (find-constant
186 (first (member-type-members type)))))))
187 (reoptimize-lvar lvar)))))
190 ;;; This is similar to DERIVE-NODE-TYPE, but asserts that it is an
191 ;;; error for LVAR's value not to be TYPEP to TYPE. We implement it
192 ;;; splitting off DEST a new CAST node; old LVAR will deliver values
193 ;;; to CAST. If we improve the assertion, we set TYPE-CHECK and
194 ;;; TYPE-ASSERTED to guarantee that the new assertion will be checked.
195 (defun assert-lvar-type (lvar type policy)
196 (declare (type lvar lvar) (type ctype type))
197 (unless (values-subtypep (lvar-derived-type lvar) type)
198 (let ((internal-lvar (make-lvar))
199 (dest (lvar-dest lvar)))
200 (substitute-lvar internal-lvar lvar)
201 (let ((cast (insert-cast-before dest lvar type policy)))
202 (use-lvar cast internal-lvar))))
208 ;;; Do one forward pass over COMPONENT, deleting unreachable blocks
209 ;;; and doing IR1 optimizations. We can ignore all blocks that don't
210 ;;; have the REOPTIMIZE flag set. If COMPONENT-REOPTIMIZE is true when
211 ;;; we are done, then another iteration would be beneficial.
212 (defun ir1-optimize (component fastp)
213 (declare (type component component))
214 (setf (component-reoptimize component) nil)
215 (loop with block = (block-next (component-head component))
216 with tail = (component-tail component)
217 for last-block = block
218 until (eq block tail)
220 ;; We delete blocks when there is either no predecessor or the
221 ;; block is in a lambda that has been deleted. These blocks
222 ;; would eventually be deleted by DFO recomputation, but doing
223 ;; it here immediately makes the effect available to IR1
225 ((or (block-delete-p block)
226 (null (block-pred block)))
227 (delete-block-lazily block)
228 (setq block (clean-component component block)))
229 ((eq (functional-kind (block-home-lambda block)) :deleted)
230 ;; Preserve the BLOCK-SUCC invariant that almost every block has
231 ;; one successor (and a block with DELETE-P set is an acceptable
233 (mark-for-deletion block)
234 (setq block (clean-component component block)))
237 (let ((succ (block-succ block)))
238 (unless (singleton-p succ)
241 (let ((last (block-last block)))
244 (flush-dest (if-test last))
245 (when (unlink-node last)
248 (when (maybe-delete-exit last)
251 (unless (join-successor-if-possible block)
254 (when (and (not fastp) (block-reoptimize block) (block-component block))
255 (aver (not (block-delete-p block)))
256 (ir1-optimize-block block))
258 (cond ((and (block-delete-p block) (block-component block))
259 (setq block (clean-component component block)))
260 ((and (block-flush-p block) (block-component block))
261 (flush-dead-code block)))))
262 do (when (eq block last-block)
263 (setq block (block-next block))))
267 ;;; Loop over the nodes in BLOCK, acting on (and clearing) REOPTIMIZE
270 ;;; Note that although they are cleared here, REOPTIMIZE flags might
271 ;;; still be set upon return from this function, meaning that further
272 ;;; optimization is wanted (as a consequence of optimizations we did).
273 (defun ir1-optimize-block (block)
274 (declare (type cblock block))
275 ;; We clear the node and block REOPTIMIZE flags before doing the
276 ;; optimization, not after. This ensures that the node or block will
277 ;; be reoptimized if necessary.
278 (setf (block-reoptimize block) nil)
279 (do-nodes (node nil block :restart-p t)
280 (when (node-reoptimize node)
281 ;; As above, we clear the node REOPTIMIZE flag before optimizing.
282 (setf (node-reoptimize node) nil)
286 ;; With a COMBINATION, we call PROPAGATE-FUN-CHANGE whenever
287 ;; the function changes, and call IR1-OPTIMIZE-COMBINATION if
288 ;; any argument changes.
289 (ir1-optimize-combination node))
291 (ir1-optimize-if node))
293 ;; KLUDGE: We leave the NODE-OPTIMIZE flag set going into
294 ;; IR1-OPTIMIZE-RETURN, since IR1-OPTIMIZE-RETURN wants to
295 ;; clear the flag itself. -- WHN 2002-02-02, quoting original
297 (setf (node-reoptimize node) t)
298 (ir1-optimize-return node))
300 (ir1-optimize-mv-combination node))
302 ;; With an EXIT, we derive the node's type from the VALUE's
304 (let ((value (exit-value node)))
306 (derive-node-type node (lvar-derived-type value)))))
308 (ir1-optimize-set node))
310 (ir1-optimize-cast node)))))
314 ;;; Try to join with a successor block. If we succeed, we return true,
316 (defun join-successor-if-possible (block)
317 (declare (type cblock block))
318 (let ((next (first (block-succ block))))
319 (when (block-start next) ; NEXT is not an END-OF-COMPONENT marker
320 (cond ( ;; We cannot combine with a successor block if:
322 ;; the successor has more than one predecessor;
323 (rest (block-pred next))
324 ;; the successor is the current block (infinite loop);
326 ;; the next block has a different cleanup, and thus
327 ;; we may want to insert cleanup code between the
328 ;; two blocks at some point;
329 (not (eq (block-end-cleanup block)
330 (block-start-cleanup next)))
331 ;; the next block has a different home lambda, and
332 ;; thus the control transfer is a non-local exit.
333 (not (eq (block-home-lambda block)
334 (block-home-lambda next)))
335 ;; Stack analysis phase wants ENTRY to start a block...
336 (entry-p (block-start-node next))
337 (let ((last (block-last block)))
338 (and (valued-node-p last)
339 (awhen (node-lvar last)
341 ;; ... and a DX-allocator to end a block.
342 (lvar-dynamic-extent it)
343 ;; FIXME: This is a partial workaround for bug 303.
344 (consp (lvar-uses it)))))))
347 (join-blocks block next)
350 ;;; Join together two blocks. The code in BLOCK2 is moved into BLOCK1
351 ;;; and BLOCK2 is deleted from the DFO. We combine the optimize flags
352 ;;; for the two blocks so that any indicated optimization gets done.
353 (defun join-blocks (block1 block2)
354 (declare (type cblock block1 block2))
355 (let* ((last1 (block-last block1))
356 (last2 (block-last block2))
357 (succ (block-succ block2))
358 (start2 (block-start block2)))
359 (do ((ctran start2 (node-next (ctran-next ctran))))
361 (setf (ctran-block ctran) block1))
363 (unlink-blocks block1 block2)
365 (unlink-blocks block2 block)
366 (link-blocks block1 block))
368 (setf (ctran-kind start2) :inside-block)
369 (setf (node-next last1) start2)
370 (setf (ctran-use start2) last1)
371 (setf (block-last block1) last2))
373 (setf (block-flags block1)
374 (attributes-union (block-flags block1)
376 (block-attributes type-asserted test-modified)))
378 (let ((next (block-next block2))
379 (prev (block-prev block2)))
380 (setf (block-next prev) next)
381 (setf (block-prev next) prev))
385 ;;; Delete any nodes in BLOCK whose value is unused and which have no
386 ;;; side effects. We can delete sets of lexical variables when the set
387 ;;; variable has no references.
388 (defun flush-dead-code (block)
389 (declare (type cblock block))
390 (setf (block-flush-p block) nil)
391 (do-nodes-backwards (node lvar block :restart-p t)
398 (let ((kind (combination-kind node))
399 (info (combination-fun-info node)))
400 (when (and (eq kind :known) (fun-info-p info))
401 (let ((attr (fun-info-attributes info)))
402 (when (and (not (ir1-attributep attr call))
403 ;; ### For now, don't delete potentially
404 ;; flushable calls when they have the CALL
405 ;; attribute. Someday we should look at the
406 ;; functional args to determine if they have
408 (if (policy node (= safety 3))
409 (ir1-attributep attr flushable)
410 (ir1-attributep attr unsafely-flushable)))
411 (flush-combination node))))))
413 (when (eq (basic-combination-kind node) :local)
414 (let ((fun (combination-lambda node)))
415 (when (dolist (var (lambda-vars fun) t)
416 (when (or (leaf-refs var)
417 (lambda-var-sets var))
419 (flush-dest (first (basic-combination-args node)))
422 (let ((value (exit-value node)))
425 (setf (exit-value node) nil))))
427 (let ((var (set-var node)))
428 (when (and (lambda-var-p var)
429 (null (leaf-refs var)))
430 (flush-dest (set-value node))
431 (setf (basic-var-sets var)
432 (delq node (basic-var-sets var)))
433 (unlink-node node))))
435 (unless (cast-type-check node)
436 (flush-dest (cast-value node))
437 (unlink-node node))))))
441 ;;;; local call return type propagation
443 ;;; This function is called on RETURN nodes that have their REOPTIMIZE
444 ;;; flag set. It iterates over the uses of the RESULT, looking for
445 ;;; interesting stuff to update the TAIL-SET. If a use isn't a local
446 ;;; call, then we union its type together with the types of other such
447 ;;; uses. We assign to the RETURN-RESULT-TYPE the intersection of this
448 ;;; type with the RESULT's asserted type. We can make this
449 ;;; intersection now (potentially before type checking) because this
450 ;;; assertion on the result will eventually be checked (if
453 ;;; We call MAYBE-CONVERT-TAIL-LOCAL-CALL on each local non-MV
454 ;;; combination, which may change the successor of the call to be the
455 ;;; called function, and if so, checks if the call can become an
456 ;;; assignment. If we convert to an assignment, we abort, since the
457 ;;; RETURN has been deleted.
458 (defun find-result-type (node)
459 (declare (type creturn node))
460 (let ((result (return-result node)))
461 (collect ((use-union *empty-type* values-type-union))
462 (do-uses (use result)
463 (let ((use-home (node-home-lambda use)))
464 (cond ((or (eq (functional-kind use-home) :deleted)
465 (block-delete-p (node-block use))))
466 ((and (basic-combination-p use)
467 (eq (basic-combination-kind use) :local))
468 (aver (eq (lambda-tail-set use-home)
469 (lambda-tail-set (combination-lambda use))))
470 (when (combination-p use)
471 (when (nth-value 1 (maybe-convert-tail-local-call use))
472 (return-from find-result-type t))))
474 (use-union (node-derived-type use))))))
476 ;; (values-type-intersection
477 ;; (continuation-asserted-type result) ; FIXME -- APD, 2002-01-26
481 (setf (return-result-type node) int))))
484 ;;; Do stuff to realize that something has changed about the value
485 ;;; delivered to a return node. Since we consider the return values of
486 ;;; all functions in the tail set to be equivalent, this amounts to
487 ;;; bringing the entire tail set up to date. We iterate over the
488 ;;; returns for all the functions in the tail set, reanalyzing them
489 ;;; all (not treating NODE specially.)
491 ;;; When we are done, we check whether the new type is different from
492 ;;; the old TAIL-SET-TYPE. If so, we set the type and also reoptimize
493 ;;; all the lvars for references to functions in the tail set. This
494 ;;; will cause IR1-OPTIMIZE-COMBINATION to derive the new type as the
495 ;;; results of the calls.
496 (defun ir1-optimize-return (node)
497 (declare (type creturn node))
500 (let* ((tails (lambda-tail-set (return-lambda node)))
501 (funs (tail-set-funs tails)))
502 (collect ((res *empty-type* values-type-union))
504 (let ((return (lambda-return fun)))
506 (when (node-reoptimize return)
507 (setf (node-reoptimize return) nil)
508 (when (find-result-type return)
510 (res (return-result-type return)))))
512 (when (type/= (res) (tail-set-type tails))
513 (setf (tail-set-type tails) (res))
514 (dolist (fun (tail-set-funs tails))
515 (dolist (ref (leaf-refs fun))
516 (reoptimize-lvar (node-lvar ref))))))))
522 ;;; If the test has multiple uses, replicate the node when possible.
523 ;;; Also check whether the predicate is known to be true or false,
524 ;;; deleting the IF node in favor of the appropriate branch when this
526 (defun ir1-optimize-if (node)
527 (declare (type cif node))
528 (let ((test (if-test node))
529 (block (node-block node)))
531 (when (and (eq (block-start-node block) node)
532 (listp (lvar-uses test)))
534 (when (immediately-used-p test use)
535 (convert-if-if use node)
536 (when (not (listp (lvar-uses test))) (return)))))
538 (let* ((type (lvar-type test))
540 (cond ((constant-lvar-p test)
541 (if (lvar-value test)
542 (if-alternative node)
543 (if-consequent node)))
544 ((not (types-equal-or-intersect type (specifier-type 'null)))
545 (if-alternative node))
546 ((type= type (specifier-type 'null))
547 (if-consequent node)))))
550 (when (rest (block-succ block))
551 (unlink-blocks block victim))
552 (setf (component-reanalyze (node-component node)) t)
553 (unlink-node node))))
556 ;;; Create a new copy of an IF node that tests the value of the node
557 ;;; USE. The test must have >1 use, and must be immediately used by
558 ;;; USE. NODE must be the only node in its block (implying that
559 ;;; block-start = if-test).
561 ;;; This optimization has an effect semantically similar to the
562 ;;; source-to-source transformation:
563 ;;; (IF (IF A B C) D E) ==>
564 ;;; (IF A (IF B D E) (IF C D E))
566 ;;; We clobber the NODE-SOURCE-PATH of both the original and the new
567 ;;; node so that dead code deletion notes will definitely not consider
568 ;;; either node to be part of the original source. One node might
569 ;;; become unreachable, resulting in a spurious note.
570 (defun convert-if-if (use node)
571 (declare (type node use) (type cif node))
572 (with-ir1-environment-from-node node
573 (let* ((block (node-block node))
574 (test (if-test node))
575 (cblock (if-consequent node))
576 (ablock (if-alternative node))
577 (use-block (node-block use))
578 (new-ctran (make-ctran))
579 (new-lvar (make-lvar))
580 (new-node (make-if :test new-lvar
582 :alternative ablock))
583 (new-block (ctran-starts-block new-ctran)))
584 (link-node-to-previous-ctran new-node new-ctran)
585 (setf (lvar-dest new-lvar) new-node)
586 (setf (block-last new-block) new-node)
588 (unlink-blocks use-block block)
589 (%delete-lvar-use use)
590 (add-lvar-use use new-lvar)
591 (link-blocks use-block new-block)
593 (link-blocks new-block cblock)
594 (link-blocks new-block ablock)
596 (push "<IF Duplication>" (node-source-path node))
597 (push "<IF Duplication>" (node-source-path new-node))
599 (reoptimize-lvar test)
600 (reoptimize-lvar new-lvar)
601 (setf (component-reanalyze *current-component*) t)))
604 ;;;; exit IR1 optimization
606 ;;; This function attempts to delete an exit node, returning true if
607 ;;; it deletes the block as a consequence:
608 ;;; -- If the exit is degenerate (has no ENTRY), then we don't do
609 ;;; anything, since there is nothing to be done.
610 ;;; -- If the exit node and its ENTRY have the same home lambda then
611 ;;; we know the exit is local, and can delete the exit. We change
612 ;;; uses of the Exit-Value to be uses of the original lvar,
613 ;;; then unlink the node. If the exit is to a TR context, then we
614 ;;; must do MERGE-TAIL-SETS on any local calls which delivered
615 ;;; their value to this exit.
616 ;;; -- If there is no value (as in a GO), then we skip the value
619 ;;; This function is also called by environment analysis, since it
620 ;;; wants all exits to be optimized even if normal optimization was
622 (defun maybe-delete-exit (node)
623 (declare (type exit node))
624 (let ((value (exit-value node))
625 (entry (exit-entry node)))
627 (eq (node-home-lambda node) (node-home-lambda entry)))
628 (setf (entry-exits entry) (delq node (entry-exits entry)))
630 (delete-filter node (node-lvar node) value)
631 (unlink-node node)))))
634 ;;;; combination IR1 optimization
636 ;;; Report as we try each transform?
638 (defvar *show-transforms-p* nil)
640 (defun check-important-result (node info)
641 (when (and (null (node-lvar node))
642 (ir1-attributep (fun-info-attributes info) important-result))
643 (let ((*compiler-error-context* node))
645 "The return value of ~A should not be discarded."
646 (lvar-fun-name (basic-combination-fun node))))))
648 ;;; Do IR1 optimizations on a COMBINATION node.
649 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
650 (defun ir1-optimize-combination (node)
651 (when (lvar-reoptimize (basic-combination-fun node))
652 (propagate-fun-change node)
653 (maybe-terminate-block node nil))
654 (let ((args (basic-combination-args node))
655 (kind (basic-combination-kind node))
656 (info (basic-combination-fun-info node)))
659 (let ((fun (combination-lambda node)))
660 (if (eq (functional-kind fun) :let)
661 (propagate-let-args node fun)
662 (propagate-local-call-args node fun))))
666 (setf (lvar-reoptimize arg) nil))))
670 (setf (lvar-reoptimize arg) nil)))
672 (check-important-result node info)
673 (let ((fun (fun-info-destroyed-constant-args info)))
675 (let ((destroyed-constant-args (funcall fun args)))
676 (when destroyed-constant-args
677 (let ((*compiler-error-context* node))
678 (warn 'constant-modified
679 :fun-name (lvar-fun-name
680 (basic-combination-fun node)))
681 (setf (basic-combination-kind node) :error)
682 (return-from ir1-optimize-combination))))))
683 (let ((fun (fun-info-derive-type info)))
685 (let ((res (funcall fun node)))
687 (derive-node-type node (coerce-to-values res))
688 (maybe-terminate-block node nil)))))))
693 (setf (lvar-reoptimize arg) nil)))
694 (check-important-result node info)
695 (let ((fun (fun-info-destroyed-constant-args info)))
697 ;; If somebody is really sure that they want to modify
698 ;; constants, let them.
699 (policy node (> safety 0)))
700 (let ((destroyed-constant-args (funcall fun args)))
701 (when destroyed-constant-args
702 (let ((*compiler-error-context* node))
703 (warn 'constant-modified
704 :fun-name (lvar-fun-name
705 (basic-combination-fun node)))
706 (setf (basic-combination-kind node) :error)
707 (return-from ir1-optimize-combination))))))
709 (let ((attr (fun-info-attributes info)))
710 (when (and (ir1-attributep attr foldable)
711 ;; KLUDGE: The next test could be made more sensitive,
712 ;; only suppressing constant-folding of functions with
713 ;; CALL attributes when they're actually passed
714 ;; function arguments. -- WHN 19990918
715 (not (ir1-attributep attr call))
716 (every #'constant-lvar-p args)
718 (constant-fold-call node)
719 (return-from ir1-optimize-combination)))
721 (let ((fun (fun-info-derive-type info)))
723 (let ((res (funcall fun node)))
725 (derive-node-type node (coerce-to-values res))
726 (maybe-terminate-block node nil)))))
728 (let ((fun (fun-info-optimizer info)))
729 (unless (and fun (funcall fun node))
730 ;; First give the VM a peek at the call
731 (multiple-value-bind (style transform)
732 (combination-implementation-style node)
735 ;; The VM knows how to handle this.
738 ;; The VM mostly knows how to handle this. We need
739 ;; to massage the call slightly, though.
740 (transform-call node transform (combination-fun-source-name node)))
742 ;; Let transforms have a crack at it.
743 (dolist (x (fun-info-transforms info))
745 (when *show-transforms-p*
746 (let* ((lvar (basic-combination-fun node))
747 (fname (lvar-fun-name lvar t)))
748 (/show "trying transform" x (transform-function x) "for" fname)))
749 (unless (ir1-transform node x)
751 (when *show-transforms-p*
752 (/show "quitting because IR1-TRANSFORM result was NIL"))
757 ;;; If NODE doesn't return (i.e. return type is NIL), then terminate
758 ;;; the block there, and link it to the component tail.
760 ;;; Except when called during IR1 convertion, we delete the
761 ;;; continuation if it has no other uses. (If it does have other uses,
764 ;;; Termination on the basis of a continuation type is
766 ;;; -- The continuation is deleted (hence the assertion is spurious), or
767 ;;; -- We are in IR1 conversion (where THE assertions are subject to
768 ;;; weakening.) FIXME: Now THE assertions are not weakened, but new
769 ;;; uses can(?) be added later. -- APD, 2003-07-17
771 ;;; Why do we need to consider LVAR type? -- APD, 2003-07-30
772 (defun maybe-terminate-block (node ir1-converting-not-optimizing-p)
773 (declare (type (or basic-combination cast ref) node))
774 (let* ((block (node-block node))
775 (lvar (node-lvar node))
776 (ctran (node-next node))
777 (tail (component-tail (block-component block)))
778 (succ (first (block-succ block))))
779 (declare (ignore lvar))
780 (unless (or (and (eq node (block-last block)) (eq succ tail))
781 (block-delete-p block))
782 (when (eq (node-derived-type node) *empty-type*)
783 (cond (ir1-converting-not-optimizing-p
786 (aver (eq (block-last block) node)))
788 (setf (block-last block) node)
789 (setf (ctran-use ctran) nil)
790 (setf (ctran-kind ctran) :unused)
791 (setf (ctran-block ctran) nil)
792 (setf (node-next node) nil)
793 (link-blocks block (ctran-starts-block ctran)))))
795 (node-ends-block node)))
797 (let ((succ (first (block-succ block))))
798 (unlink-blocks block succ)
799 (setf (component-reanalyze (block-component block)) t)
800 (aver (not (block-succ block)))
801 (link-blocks block tail)
802 (cond (ir1-converting-not-optimizing-p
803 (%delete-lvar-use node))
804 (t (delete-lvar-use node)
805 (when (null (block-pred succ))
806 (mark-for-deletion succ)))))
809 ;;; This is called both by IR1 conversion and IR1 optimization when
810 ;;; they have verified the type signature for the call, and are
811 ;;; wondering if something should be done to special-case the call. If
812 ;;; CALL is a call to a global function, then see whether it defined
814 ;;; -- If a DEFINED-FUN should be inline expanded, then convert
815 ;;; the expansion and change the call to call it. Expansion is
816 ;;; enabled if :INLINE or if SPACE=0. If the FUNCTIONAL slot is
817 ;;; true, we never expand, since this function has already been
818 ;;; converted. Local call analysis will duplicate the definition
819 ;;; if necessary. We claim that the parent form is LABELS for
820 ;;; context declarations, since we don't want it to be considered
821 ;;; a real global function.
822 ;;; -- If it is a known function, mark it as such by setting the KIND.
824 ;;; We return the leaf referenced (NIL if not a leaf) and the
825 ;;; FUN-INFO assigned.
826 (defun recognize-known-call (call ir1-converting-not-optimizing-p)
827 (declare (type combination call))
828 (let* ((ref (lvar-uses (basic-combination-fun call)))
829 (leaf (when (ref-p ref) (ref-leaf ref)))
830 (inlinep (if (defined-fun-p leaf)
831 (defined-fun-inlinep leaf)
834 ((eq inlinep :notinline)
835 (let ((info (info :function :info (leaf-source-name leaf))))
837 (setf (basic-combination-fun-info call) info))
839 ((not (and (global-var-p leaf)
840 (eq (global-var-kind leaf) :global-function)))
845 ((nil :maybe-inline) (policy call (zerop space))))
846 ;; FIXME & KLUDGE: This LET-CONVERSION check was added as a
847 ;; half-assed workaround for the bug for which the test
848 ;; case :HIGH-DEBUG-KNOWN-FUNCTION-INLINING checks in
849 ;; compiler.pure.lisp. The _real_ culprit seems to be
850 ;; the insertion of BIND/UNBIND-SENTINEL vops.
851 (policy call (plusp let-conversion))
853 (defined-fun-inline-expansion leaf)
854 (let ((fun (defined-fun-functional leaf)))
856 (and (eq inlinep :inline) (functional-kind fun))))
857 (inline-expansion-ok call))
858 (flet (;; FIXME: Is this what the old CMU CL internal documentation
859 ;; called semi-inlining? A more descriptive name would
860 ;; be nice. -- WHN 2002-01-07
862 (let* ((name (leaf-source-name leaf))
863 (res (ir1-convert-inline-expansion
865 (defined-fun-inline-expansion leaf)
868 (info :function :info name))))
869 ;; allow backward references to this function from
870 ;; following top level forms
871 (setf (defined-fun-functional leaf) res)
872 (change-ref-leaf ref res))))
873 (if ir1-converting-not-optimizing-p
875 (with-ir1-environment-from-node call
877 (locall-analyze-component *current-component*))))
879 (values (ref-leaf (lvar-uses (basic-combination-fun call)))
882 (let ((info (info :function :info (leaf-source-name leaf))))
886 (setf (basic-combination-kind call) :known)
887 (setf (basic-combination-fun-info call) info)))
888 (values leaf nil)))))))
890 ;;; Check whether CALL satisfies TYPE. If so, apply the type to the
891 ;;; call, and do MAYBE-TERMINATE-BLOCK and return the values of
892 ;;; RECOGNIZE-KNOWN-CALL. If an error, set the combination kind and
893 ;;; return NIL, NIL. If the type is just FUNCTION, then skip the
894 ;;; syntax check, arg/result type processing, but still call
895 ;;; RECOGNIZE-KNOWN-CALL, since the call might be to a known lambda,
896 ;;; and that checking is done by local call analysis.
897 (defun validate-call-type (call type ir1-converting-not-optimizing-p)
898 (declare (type combination call) (type ctype type))
899 (cond ((not (fun-type-p type))
900 (aver (multiple-value-bind (val win)
901 (csubtypep type (specifier-type 'function))
903 (recognize-known-call call ir1-converting-not-optimizing-p))
904 ((valid-fun-use call type
905 :argument-test #'always-subtypep
907 ;; KLUDGE: Common Lisp is such a dynamic
908 ;; language that all we can do here in
909 ;; general is issue a STYLE-WARNING. It
910 ;; would be nice to issue a full WARNING
911 ;; in the special case of of type
912 ;; mismatches within a compilation unit
913 ;; (as in section 3.2.2.3 of the spec)
914 ;; but at least as of sbcl-0.6.11, we
915 ;; don't keep track of whether the
916 ;; mismatched data came from the same
917 ;; compilation unit, so we can't do that.
920 ;; FIXME: Actually, I think we could
921 ;; issue a full WARNING if the call
922 ;; violates a DECLAIM FTYPE.
923 :lossage-fun #'compiler-style-warn
924 :unwinnage-fun #'compiler-notify)
925 (assert-call-type call type)
926 (maybe-terminate-block call ir1-converting-not-optimizing-p)
927 (recognize-known-call call ir1-converting-not-optimizing-p))
929 (setf (combination-kind call) :error)
932 ;;; This is called by IR1-OPTIMIZE when the function for a call has
933 ;;; changed. If the call is local, we try to LET-convert it, and
934 ;;; derive the result type. If it is a :FULL call, we validate it
935 ;;; against the type, which recognizes known calls, does inline
936 ;;; expansion, etc. If a call to a predicate in a non-conditional
937 ;;; position or to a function with a source transform, then we
938 ;;; reconvert the form to give IR1 another chance.
939 (defun propagate-fun-change (call)
940 (declare (type combination call))
941 (let ((*compiler-error-context* call)
942 (fun-lvar (basic-combination-fun call)))
943 (setf (lvar-reoptimize fun-lvar) nil)
944 (case (combination-kind call)
946 (let ((fun (combination-lambda call)))
947 (maybe-let-convert fun)
948 (unless (member (functional-kind fun) '(:let :assignment :deleted))
949 (derive-node-type call (tail-set-type (lambda-tail-set fun))))))
951 (multiple-value-bind (leaf info)
952 (validate-call-type call (lvar-type fun-lvar) nil)
953 (cond ((functional-p leaf)
954 (convert-call-if-possible
955 (lvar-uses (basic-combination-fun call))
958 ((and (global-var-p leaf)
959 (eq (global-var-kind leaf) :global-function)
960 (leaf-has-source-name-p leaf)
961 (or (info :function :source-transform (leaf-source-name leaf))
963 (ir1-attributep (fun-info-attributes info)
965 (let ((lvar (node-lvar call)))
966 (and lvar (not (if-p (lvar-dest lvar))))))))
967 (let ((name (leaf-source-name leaf))
968 (dummies (make-gensym-list
969 (length (combination-args call)))))
972 (,@(if (symbolp name)
976 (leaf-source-name leaf)))))))))
979 ;;;; known function optimization
981 ;;; Add a failed optimization note to FAILED-OPTIMZATIONS for NODE,
982 ;;; FUN and ARGS. If there is already a note for NODE and TRANSFORM,
983 ;;; replace it, otherwise add a new one.
984 (defun record-optimization-failure (node transform args)
985 (declare (type combination node) (type transform transform)
986 (type (or fun-type list) args))
987 (let* ((table (component-failed-optimizations *component-being-compiled*))
988 (found (assoc transform (gethash node table))))
990 (setf (cdr found) args)
991 (push (cons transform args) (gethash node table))))
994 ;;; Attempt to transform NODE using TRANSFORM-FUNCTION, subject to the
995 ;;; call type constraint TRANSFORM-TYPE. If we are inhibited from
996 ;;; doing the transform for some reason and FLAME is true, then we
997 ;;; make a note of the message in FAILED-OPTIMIZATIONS for IR1
998 ;;; finalize to pick up. We return true if the transform failed, and
999 ;;; thus further transformation should be attempted. We return false
1000 ;;; if either the transform succeeded or was aborted.
1001 (defun ir1-transform (node transform)
1002 (declare (type combination node) (type transform transform))
1003 (let* ((type (transform-type transform))
1004 (fun (transform-function transform))
1005 (constrained (fun-type-p type))
1006 (table (component-failed-optimizations *component-being-compiled*))
1007 (flame (if (transform-important transform)
1008 (policy node (>= speed inhibit-warnings))
1009 (policy node (> speed inhibit-warnings))))
1010 (*compiler-error-context* node))
1011 (cond ((or (not constrained)
1012 (valid-fun-use node type))
1013 (multiple-value-bind (severity args)
1014 (catch 'give-up-ir1-transform
1015 (transform-call node
1017 (combination-fun-source-name node))
1021 (remhash node table)
1024 (setf (combination-kind node) :error)
1026 (apply #'warn args))
1027 (remhash node table)
1032 (record-optimization-failure node transform args))
1033 (setf (gethash node table)
1034 (remove transform (gethash node table) :key #'car)))
1037 (remhash node table)
1042 :argument-test #'types-equal-or-intersect
1043 :result-test #'values-types-equal-or-intersect))
1044 (record-optimization-failure node transform type)
1049 ;;; When we don't like an IR1 transform, we throw the severity/reason
1052 ;;; GIVE-UP-IR1-TRANSFORM is used to throw out of an IR1 transform,
1053 ;;; aborting this attempt to transform the call, but admitting the
1054 ;;; possibility that this or some other transform will later succeed.
1055 ;;; If arguments are supplied, they are format arguments for an
1056 ;;; efficiency note.
1058 ;;; ABORT-IR1-TRANSFORM is used to throw out of an IR1 transform and
1059 ;;; force a normal call to the function at run time. No further
1060 ;;; optimizations will be attempted.
1062 ;;; DELAY-IR1-TRANSFORM is used to throw out of an IR1 transform, and
1063 ;;; delay the transform on the node until later. REASONS specifies
1064 ;;; when the transform will be later retried. The :OPTIMIZE reason
1065 ;;; causes the transform to be delayed until after the current IR1
1066 ;;; optimization pass. The :CONSTRAINT reason causes the transform to
1067 ;;; be delayed until after constraint propagation.
1069 ;;; FIXME: Now (0.6.11.44) that there are 4 variants of this (GIVE-UP,
1070 ;;; ABORT, DELAY/:OPTIMIZE, DELAY/:CONSTRAINT) and we're starting to
1071 ;;; do CASE operations on the various REASON values, it might be a
1072 ;;; good idea to go OO, representing the reasons by objects, using
1073 ;;; CLOS methods on the objects instead of CASE, and (possibly) using
1074 ;;; SIGNAL instead of THROW.
1075 (declaim (ftype (function (&rest t) nil) give-up-ir1-transform))
1076 (defun give-up-ir1-transform (&rest args)
1077 (throw 'give-up-ir1-transform (values :failure args)))
1078 (defun abort-ir1-transform (&rest args)
1079 (throw 'give-up-ir1-transform (values :aborted args)))
1080 (defun delay-ir1-transform (node &rest reasons)
1081 (let ((assoc (assoc node *delayed-ir1-transforms*)))
1083 (setf *delayed-ir1-transforms*
1084 (acons node reasons *delayed-ir1-transforms*))
1085 (throw 'give-up-ir1-transform :delayed))
1087 (dolist (reason reasons)
1088 (pushnew reason (cdr assoc)))
1089 (throw 'give-up-ir1-transform :delayed)))))
1091 ;;; Clear any delayed transform with no reasons - these should have
1092 ;;; been tried in the last pass. Then remove the reason from the
1093 ;;; delayed transform reasons, and if any become empty then set
1094 ;;; reoptimize flags for the node. Return true if any transforms are
1096 (defun retry-delayed-ir1-transforms (reason)
1097 (setf *delayed-ir1-transforms*
1098 (remove-if-not #'cdr *delayed-ir1-transforms*))
1099 (let ((reoptimize nil))
1100 (dolist (assoc *delayed-ir1-transforms*)
1101 (let ((reasons (remove reason (cdr assoc))))
1102 (setf (cdr assoc) reasons)
1104 (let ((node (car assoc)))
1105 (unless (node-deleted node)
1107 (setf (node-reoptimize node) t)
1108 (let ((block (node-block node)))
1109 (setf (block-reoptimize block) t)
1110 (reoptimize-component (block-component block) :maybe)))))))
1113 ;;; Take the lambda-expression RES, IR1 convert it in the proper
1114 ;;; environment, and then install it as the function for the call
1115 ;;; NODE. We do local call analysis so that the new function is
1116 ;;; integrated into the control flow.
1118 ;;; We require the original function source name in order to generate
1119 ;;; a meaningful debug name for the lambda we set up. (It'd be
1120 ;;; possible to do this starting from debug names as well as source
1121 ;;; names, but as of sbcl-0.7.1.5, there was no need for this
1122 ;;; generality, since source names are always known to our callers.)
1123 (defun transform-call (call res source-name)
1124 (declare (type combination call) (list res))
1125 (aver (and (legal-fun-name-p source-name)
1126 (not (eql source-name '.anonymous.))))
1127 (node-ends-block call)
1128 ;; The internal variables of a transform are not going to be
1129 ;; interesting to the debugger, so there's no sense in
1130 ;; suppressing the substitution of variables with only one use
1131 ;; (the extra variables can slow down constraint propagation).
1133 ;; This needs to be done before the WITH-IR1-ENVIRONMENT-FROM-NODE,
1134 ;; so that it will bind *LEXENV* to the right environment.
1135 (setf (combination-lexenv call)
1136 (make-lexenv :default (combination-lexenv call)
1137 :policy (process-optimize-decl
1139 (preserve-single-use-debug-variables 0))
1141 (combination-lexenv call)))))
1142 (with-ir1-environment-from-node call
1143 (with-component-last-block (*current-component*
1144 (block-next (node-block call)))
1146 (let ((new-fun (ir1-convert-inline-lambda
1148 :debug-name (debug-name 'lambda-inlined source-name)
1150 (ref (lvar-use (combination-fun call))))
1151 (change-ref-leaf ref new-fun)
1152 (setf (combination-kind call) :full)
1153 (locall-analyze-component *current-component*))))
1156 ;;; Replace a call to a foldable function of constant arguments with
1157 ;;; the result of evaluating the form. If there is an error during the
1158 ;;; evaluation, we give a warning and leave the call alone, making the
1159 ;;; call a :ERROR call.
1161 ;;; If there is more than one value, then we transform the call into a
1163 (defun constant-fold-call (call)
1164 (let ((args (mapcar #'lvar-value (combination-args call)))
1165 (fun-name (combination-fun-source-name call)))
1166 (multiple-value-bind (values win)
1167 (careful-call fun-name
1170 ;; Note: CMU CL had COMPILER-WARN here, and that
1171 ;; seems more natural, but it's probably not.
1173 ;; It's especially not while bug 173 exists:
1176 ;; (UNLESS (OR UNSAFE? (<= END SIZE)))
1178 ;; can cause constant-folding TYPE-ERRORs (in
1179 ;; #'<=) when END can be proved to be NIL, even
1180 ;; though the code is perfectly legal and safe
1181 ;; because a NIL value of END means that the
1182 ;; #'<= will never be executed.
1184 ;; Moreover, even without bug 173,
1185 ;; quite-possibly-valid code like
1186 ;; (COND ((NONINLINED-PREDICATE END)
1187 ;; (UNLESS (<= END SIZE))
1189 ;; (where NONINLINED-PREDICATE is something the
1190 ;; compiler can't do at compile time, but which
1191 ;; turns out to make the #'<= expression
1192 ;; unreachable when END=NIL) could cause errors
1193 ;; when the compiler tries to constant-fold (<=
1196 ;; So, with or without bug 173, it'd be
1197 ;; unnecessarily evil to do a full
1198 ;; COMPILER-WARNING (and thus return FAILURE-P=T
1199 ;; from COMPILE-FILE) for legal code, so we we
1200 ;; use a wimpier COMPILE-STYLE-WARNING instead.
1201 #-sb-xc-host #'compiler-style-warn
1202 ;; On the other hand, for code we control, we
1203 ;; should be able to work around any bug
1204 ;; 173-related problems, and in particular we
1205 ;; want to be alerted to calls to our own
1206 ;; functions which aren't being folded away; a
1207 ;; COMPILER-WARNING is butch enough to stop the
1208 ;; SBCL build itself in its tracks.
1209 #+sb-xc-host #'compiler-warn
1212 (setf (combination-kind call) :error))
1213 ((and (proper-list-of-length-p values 1))
1214 (with-ir1-environment-from-node call
1215 (let* ((lvar (node-lvar call))
1216 (prev (node-prev call))
1217 (intermediate-ctran (make-ctran)))
1218 (%delete-lvar-use call)
1219 (setf (ctran-next prev) nil)
1220 (setf (node-prev call) nil)
1221 (reference-constant prev intermediate-ctran lvar
1223 (link-node-to-previous-ctran call intermediate-ctran)
1224 (reoptimize-lvar lvar)
1225 (flush-combination call))))
1226 (t (let ((dummies (make-gensym-list (length args))))
1230 (declare (ignore ,@dummies))
1231 (values ,@(mapcar (lambda (x) `',x) values)))
1235 ;;;; local call optimization
1237 ;;; Propagate TYPE to LEAF and its REFS, marking things changed. If
1238 ;;; the leaf type is a function type, then just leave it alone, since
1239 ;;; TYPE is never going to be more specific than that (and
1240 ;;; TYPE-INTERSECTION would choke.)
1241 (defun propagate-to-refs (leaf type)
1242 (declare (type leaf leaf) (type ctype type))
1243 (let ((var-type (leaf-type leaf)))
1244 (unless (fun-type-p var-type)
1245 (let ((int (type-approx-intersection2 var-type type)))
1246 (when (type/= int var-type)
1247 (setf (leaf-type leaf) int)
1248 (dolist (ref (leaf-refs leaf))
1249 (derive-node-type ref (make-single-value-type int))
1250 ;; KLUDGE: LET var substitution
1251 (let* ((lvar (node-lvar ref)))
1252 (when (and lvar (combination-p (lvar-dest lvar)))
1253 (reoptimize-lvar lvar))))))
1256 ;;; Iteration variable: exactly one SETQ of the form:
1258 ;;; (let ((var initial))
1260 ;;; (setq var (+ var step))
1262 (defun maybe-infer-iteration-var-type (var initial-type)
1263 (binding* ((sets (lambda-var-sets var) :exit-if-null)
1265 (() (null (rest sets)) :exit-if-null)
1266 (set-use (principal-lvar-use (set-value set)))
1267 (() (and (combination-p set-use)
1268 (eq (combination-kind set-use) :known)
1269 (fun-info-p (combination-fun-info set-use))
1270 (not (node-to-be-deleted-p set-use))
1271 (or (eq (combination-fun-source-name set-use) '+)
1272 (eq (combination-fun-source-name set-use) '-)))
1274 (minusp (eq (combination-fun-source-name set-use) '-))
1275 (+-args (basic-combination-args set-use))
1276 (() (and (proper-list-of-length-p +-args 2 2)
1277 (let ((first (principal-lvar-use
1280 (eq (ref-leaf first) var))))
1282 (step-type (lvar-type (second +-args)))
1283 (set-type (lvar-type (set-value set))))
1284 (when (and (numeric-type-p initial-type)
1285 (numeric-type-p step-type)
1286 (or (numeric-type-equal initial-type step-type)
1287 ;; Detect cases like (LOOP FOR 1.0 to 5.0 ...), where
1288 ;; the initial and the step are of different types,
1289 ;; and the step is less contagious.
1290 (numeric-type-equal initial-type
1291 (numeric-contagion initial-type
1293 (labels ((leftmost (x y cmp cmp=)
1294 (cond ((eq x nil) nil)
1297 (let ((x1 (first x)))
1299 (let ((y1 (first y)))
1300 (if (funcall cmp x1 y1) x y)))
1302 (if (funcall cmp x1 y) x y)))))
1304 (let ((y1 (first y)))
1305 (if (funcall cmp= x y1) x y)))
1306 (t (if (funcall cmp x y) x y))))
1307 (max* (x y) (leftmost x y #'> #'>=))
1308 (min* (x y) (leftmost x y #'< #'<=)))
1309 (multiple-value-bind (low high)
1310 (let ((step-type-non-negative (csubtypep step-type (specifier-type
1312 (step-type-non-positive (csubtypep step-type (specifier-type
1314 (cond ((or (and step-type-non-negative (not minusp))
1315 (and step-type-non-positive minusp))
1316 (values (numeric-type-low initial-type)
1317 (when (and (numeric-type-p set-type)
1318 (numeric-type-equal set-type initial-type))
1319 (max* (numeric-type-high initial-type)
1320 (numeric-type-high set-type)))))
1321 ((or (and step-type-non-positive (not minusp))
1322 (and step-type-non-negative minusp))
1323 (values (when (and (numeric-type-p set-type)
1324 (numeric-type-equal set-type initial-type))
1325 (min* (numeric-type-low initial-type)
1326 (numeric-type-low set-type)))
1327 (numeric-type-high initial-type)))
1330 (modified-numeric-type initial-type
1333 :enumerable nil))))))
1334 (deftransform + ((x y) * * :result result)
1335 "check for iteration variable reoptimization"
1336 (let ((dest (principal-lvar-end result))
1337 (use (principal-lvar-use x)))
1338 (when (and (ref-p use)
1342 (reoptimize-lvar (set-value dest))))
1343 (give-up-ir1-transform))
1345 ;;; Figure out the type of a LET variable that has sets. We compute
1346 ;;; the union of the INITIAL-TYPE and the types of all the set
1347 ;;; values and to a PROPAGATE-TO-REFS with this type.
1348 (defun propagate-from-sets (var initial-type)
1349 (collect ((res initial-type type-union))
1350 (dolist (set (basic-var-sets var))
1351 (let ((type (lvar-type (set-value set))))
1353 (when (node-reoptimize set)
1354 (derive-node-type set (make-single-value-type type))
1355 (setf (node-reoptimize set) nil))))
1357 (awhen (maybe-infer-iteration-var-type var initial-type)
1359 (propagate-to-refs var res)))
1362 ;;; If a LET variable, find the initial value's type and do
1363 ;;; PROPAGATE-FROM-SETS. We also derive the VALUE's type as the node's
1365 (defun ir1-optimize-set (node)
1366 (declare (type cset node))
1367 (let ((var (set-var node)))
1368 (when (and (lambda-var-p var) (leaf-refs var))
1369 (let ((home (lambda-var-home var)))
1370 (when (eq (functional-kind home) :let)
1371 (let* ((initial-value (let-var-initial-value var))
1372 (initial-type (lvar-type initial-value)))
1373 (setf (lvar-reoptimize initial-value) nil)
1374 (propagate-from-sets var initial-type))))))
1376 (derive-node-type node (make-single-value-type
1377 (lvar-type (set-value node))))
1380 ;;; Return true if the value of REF will always be the same (and is
1381 ;;; thus legal to substitute.)
1382 (defun constant-reference-p (ref)
1383 (declare (type ref ref))
1384 (let ((leaf (ref-leaf ref)))
1386 ((or constant functional) t)
1388 (null (lambda-var-sets leaf)))
1390 (not (eq (defined-fun-inlinep leaf) :notinline)))
1392 (case (global-var-kind leaf)
1394 (let ((name (leaf-source-name leaf)))
1396 (eq (symbol-package (fun-name-block-name name))
1398 (info :function :info name)))))))))
1400 ;;; If we have a non-set LET var with a single use, then (if possible)
1401 ;;; replace the variable reference's LVAR with the arg lvar.
1403 ;;; We change the REF to be a reference to NIL with unused value, and
1404 ;;; let it be flushed as dead code. A side effect of this substitution
1405 ;;; is to delete the variable.
1406 (defun substitute-single-use-lvar (arg var)
1407 (declare (type lvar arg) (type lambda-var var))
1408 (binding* ((ref (first (leaf-refs var)))
1409 (lvar (node-lvar ref) :exit-if-null)
1410 (dest (lvar-dest lvar)))
1412 ;; Think about (LET ((A ...)) (IF ... A ...)): two
1413 ;; LVAR-USEs should not be met on one path. Another problem
1414 ;; is with dynamic-extent.
1415 (eq (lvar-uses lvar) ref)
1416 (not (block-delete-p (node-block ref)))
1418 ;; we should not change lifetime of unknown values lvars
1420 (and (type-single-value-p (lvar-derived-type arg))
1421 (multiple-value-bind (pdest pprev)
1422 (principal-lvar-end lvar)
1423 (declare (ignore pdest))
1424 (lvar-single-value-p pprev))))
1426 (or (eq (basic-combination-fun dest) lvar)
1427 (and (eq (basic-combination-kind dest) :local)
1428 (type-single-value-p (lvar-derived-type arg)))))
1430 ;; While CRETURN and EXIT nodes may be known-values,
1431 ;; they have their own complications, such as
1432 ;; substitution into CRETURN may create new tail calls.
1435 (aver (lvar-single-value-p lvar))
1437 (eq (node-home-lambda ref)
1438 (lambda-home (lambda-var-home var))))
1439 (let ((ref-type (single-value-type (node-derived-type ref))))
1440 (cond ((csubtypep (single-value-type (lvar-type arg)) ref-type)
1441 (substitute-lvar-uses lvar arg
1442 ;; Really it is (EQ (LVAR-USES LVAR) REF):
1444 (delete-lvar-use ref))
1446 (let* ((value (make-lvar))
1447 (cast (insert-cast-before ref value ref-type
1448 ;; KLUDGE: it should be (TYPE-CHECK 0)
1450 (setf (cast-type-to-check cast) *wild-type*)
1451 (substitute-lvar-uses value arg
1454 (%delete-lvar-use ref)
1455 (add-lvar-use cast lvar)))))
1456 (setf (node-derived-type ref) *wild-type*)
1457 (change-ref-leaf ref (find-constant nil))
1460 (reoptimize-lvar lvar)
1463 ;;; Delete a LET, removing the call and bind nodes, and warning about
1464 ;;; any unreferenced variables. Note that FLUSH-DEAD-CODE will come
1465 ;;; along right away and delete the REF and then the lambda, since we
1466 ;;; flush the FUN lvar.
1467 (defun delete-let (clambda)
1468 (declare (type clambda clambda))
1469 (aver (functional-letlike-p clambda))
1470 (note-unreferenced-vars clambda)
1471 (let ((call (let-combination clambda)))
1472 (flush-dest (basic-combination-fun call))
1474 (unlink-node (lambda-bind clambda))
1475 (setf (lambda-bind clambda) nil))
1476 (setf (functional-kind clambda) :zombie)
1477 (let ((home (lambda-home clambda)))
1478 (setf (lambda-lets home) (delete clambda (lambda-lets home))))
1481 ;;; This function is called when one of the arguments to a LET
1482 ;;; changes. We look at each changed argument. If the corresponding
1483 ;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
1484 ;;; consider substituting for the variable, and also propagate
1485 ;;; derived-type information for the arg to all the VAR's refs.
1487 ;;; Substitution is inhibited when the arg leaf's derived type isn't a
1488 ;;; subtype of the argument's leaf type. This prevents type checking
1489 ;;; from being defeated, and also ensures that the best representation
1490 ;;; for the variable can be used.
1492 ;;; Substitution of individual references is inhibited if the
1493 ;;; reference is in a different component from the home. This can only
1494 ;;; happen with closures over top level lambda vars. In such cases,
1495 ;;; the references may have already been compiled, and thus can't be
1496 ;;; retroactively modified.
1498 ;;; If all of the variables are deleted (have no references) when we
1499 ;;; are done, then we delete the LET.
1501 ;;; Note that we are responsible for clearing the LVAR-REOPTIMIZE
1503 (defun propagate-let-args (call fun)
1504 (declare (type combination call) (type clambda fun))
1505 (loop for arg in (combination-args call)
1506 and var in (lambda-vars fun) do
1507 (when (and arg (lvar-reoptimize arg))
1508 (setf (lvar-reoptimize arg) nil)
1510 ((lambda-var-sets var)
1511 (propagate-from-sets var (lvar-type arg)))
1512 ((let ((use (lvar-uses arg)))
1514 (let ((leaf (ref-leaf use)))
1515 (when (and (constant-reference-p use)
1516 (csubtypep (leaf-type leaf)
1517 ;; (NODE-DERIVED-TYPE USE) would
1518 ;; be better -- APD, 2003-05-15
1520 (propagate-to-refs var (lvar-type arg))
1521 (let ((use-component (node-component use)))
1522 (prog1 (substitute-leaf-if
1524 (cond ((eq (node-component ref) use-component)
1527 (aver (lambda-toplevelish-p (lambda-home fun)))
1531 ((and (null (rest (leaf-refs var)))
1532 ;; Don't substitute single-ref variables on high-debug /
1533 ;; low speed, to improve the debugging experience.
1534 (policy call (< preserve-single-use-debug-variables 3))
1535 (substitute-single-use-lvar arg var)))
1537 (propagate-to-refs var (lvar-type arg))))))
1539 (when (every #'not (combination-args call))
1544 ;;; This function is called when one of the args to a non-LET local
1545 ;;; call changes. For each changed argument corresponding to an unset
1546 ;;; variable, we compute the union of the types across all calls and
1547 ;;; propagate this type information to the var's refs.
1549 ;;; If the function has an XEP, then we don't do anything, since we
1550 ;;; won't discover anything.
1552 ;;; We can clear the LVAR-REOPTIMIZE flags for arguments in all calls
1553 ;;; corresponding to changed arguments in CALL, since the only use in
1554 ;;; IR1 optimization of the REOPTIMIZE flag for local call args is
1556 (defun propagate-local-call-args (call fun)
1557 (declare (type combination call) (type clambda fun))
1559 (unless (or (functional-entry-fun fun)
1560 (lambda-optional-dispatch fun))
1561 (let* ((vars (lambda-vars fun))
1562 (union (mapcar (lambda (arg var)
1564 (lvar-reoptimize arg)
1565 (null (basic-var-sets var)))
1567 (basic-combination-args call)
1569 (this-ref (lvar-use (basic-combination-fun call))))
1571 (dolist (arg (basic-combination-args call))
1573 (setf (lvar-reoptimize arg) nil)))
1575 (dolist (ref (leaf-refs fun))
1576 (let ((dest (node-dest ref)))
1577 (unless (or (eq ref this-ref) (not dest))
1579 (mapcar (lambda (this-arg old)
1581 (setf (lvar-reoptimize this-arg) nil)
1582 (type-union (lvar-type this-arg) old)))
1583 (basic-combination-args dest)
1586 (loop for var in vars
1588 when type do (propagate-to-refs var type))))
1592 ;;;; multiple values optimization
1594 ;;; Do stuff to notice a change to a MV combination node. There are
1595 ;;; two main branches here:
1596 ;;; -- If the call is local, then it is already a MV let, or should
1597 ;;; become one. Note that although all :LOCAL MV calls must eventually
1598 ;;; be converted to :MV-LETs, there can be a window when the call
1599 ;;; is local, but has not been LET converted yet. This is because
1600 ;;; the entry-point lambdas may have stray references (in other
1601 ;;; entry points) that have not been deleted yet.
1602 ;;; -- The call is full. This case is somewhat similar to the non-MV
1603 ;;; combination optimization: we propagate return type information and
1604 ;;; notice non-returning calls. We also have an optimization
1605 ;;; which tries to convert MV-CALLs into MV-binds.
1606 (defun ir1-optimize-mv-combination (node)
1607 (ecase (basic-combination-kind node)
1609 (let ((fun-lvar (basic-combination-fun node)))
1610 (when (lvar-reoptimize fun-lvar)
1611 (setf (lvar-reoptimize fun-lvar) nil)
1612 (maybe-let-convert (combination-lambda node))))
1613 (setf (lvar-reoptimize (first (basic-combination-args node))) nil)
1614 (when (eq (functional-kind (combination-lambda node)) :mv-let)
1615 (unless (convert-mv-bind-to-let node)
1616 (ir1-optimize-mv-bind node))))
1618 (let* ((fun (basic-combination-fun node))
1619 (fun-changed (lvar-reoptimize fun))
1620 (args (basic-combination-args node)))
1622 (setf (lvar-reoptimize fun) nil)
1623 (let ((type (lvar-type fun)))
1624 (when (fun-type-p type)
1625 (derive-node-type node (fun-type-returns type))))
1626 (maybe-terminate-block node nil)
1627 (let ((use (lvar-uses fun)))
1628 (when (and (ref-p use) (functional-p (ref-leaf use)))
1629 (convert-call-if-possible use node)
1630 (when (eq (basic-combination-kind node) :local)
1631 (maybe-let-convert (ref-leaf use))))))
1632 (unless (or (eq (basic-combination-kind node) :local)
1633 (eq (lvar-fun-name fun) '%throw))
1634 (ir1-optimize-mv-call node))
1636 (setf (lvar-reoptimize arg) nil))))
1640 ;;; Propagate derived type info from the values lvar to the vars.
1641 (defun ir1-optimize-mv-bind (node)
1642 (declare (type mv-combination node))
1643 (let* ((arg (first (basic-combination-args node)))
1644 (vars (lambda-vars (combination-lambda node)))
1645 (n-vars (length vars))
1646 (types (values-type-in (lvar-derived-type arg)
1648 (loop for var in vars
1650 do (if (basic-var-sets var)
1651 (propagate-from-sets var type)
1652 (propagate-to-refs var type)))
1653 (setf (lvar-reoptimize arg) nil))
1656 ;;; If possible, convert a general MV call to an MV-BIND. We can do
1658 ;;; -- The call has only one argument, and
1659 ;;; -- The function has a known fixed number of arguments, or
1660 ;;; -- The argument yields a known fixed number of values.
1662 ;;; What we do is change the function in the MV-CALL to be a lambda
1663 ;;; that "looks like an MV bind", which allows
1664 ;;; IR1-OPTIMIZE-MV-COMBINATION to notice that this call can be
1665 ;;; converted (the next time around.) This new lambda just calls the
1666 ;;; actual function with the MV-BIND variables as arguments. Note that
1667 ;;; this new MV bind is not let-converted immediately, as there are
1668 ;;; going to be stray references from the entry-point functions until
1669 ;;; they get deleted.
1671 ;;; In order to avoid loss of argument count checking, we only do the
1672 ;;; transformation according to a known number of expected argument if
1673 ;;; safety is unimportant. We can always convert if we know the number
1674 ;;; of actual values, since the normal call that we build will still
1675 ;;; do any appropriate argument count checking.
1677 ;;; We only attempt the transformation if the called function is a
1678 ;;; constant reference. This allows us to just splice the leaf into
1679 ;;; the new function, instead of trying to somehow bind the function
1680 ;;; expression. The leaf must be constant because we are evaluating it
1681 ;;; again in a different place. This also has the effect of squelching
1682 ;;; multiple warnings when there is an argument count error.
1683 (defun ir1-optimize-mv-call (node)
1684 (let ((fun (basic-combination-fun node))
1685 (*compiler-error-context* node)
1686 (ref (lvar-uses (basic-combination-fun node)))
1687 (args (basic-combination-args node)))
1689 (unless (and (ref-p ref) (constant-reference-p ref)
1691 (return-from ir1-optimize-mv-call))
1693 (multiple-value-bind (min max)
1694 (fun-type-nargs (lvar-type fun))
1696 (multiple-value-bind (types nvals)
1697 (values-types (lvar-derived-type (first args)))
1698 (declare (ignore types))
1699 (if (eq nvals :unknown) nil nvals))))
1702 (when (and min (< total-nvals min))
1704 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1707 (setf (basic-combination-kind node) :error)
1708 (return-from ir1-optimize-mv-call))
1709 (when (and max (> total-nvals max))
1711 "MULTIPLE-VALUE-CALL with ~R values when the function expects ~
1714 (setf (basic-combination-kind node) :error)
1715 (return-from ir1-optimize-mv-call)))
1717 (let ((count (cond (total-nvals)
1718 ((and (policy node (zerop verify-arg-count))
1723 (with-ir1-environment-from-node node
1724 (let* ((dums (make-gensym-list count))
1726 (fun (ir1-convert-lambda
1727 `(lambda (&optional ,@dums &rest ,ignore)
1728 (declare (ignore ,ignore))
1729 (funcall ,(ref-leaf ref) ,@dums)))))
1730 (change-ref-leaf ref fun)
1731 (aver (eq (basic-combination-kind node) :full))
1732 (locall-analyze-component *current-component*)
1733 (aver (eq (basic-combination-kind node) :local)))))))))
1737 ;;; (multiple-value-bind
1746 ;;; What we actually do is convert the VALUES combination into a
1747 ;;; normal LET combination calling the original :MV-LET lambda. If
1748 ;;; there are extra args to VALUES, discard the corresponding
1749 ;;; lvars. If there are insufficient args, insert references to NIL.
1750 (defun convert-mv-bind-to-let (call)
1751 (declare (type mv-combination call))
1752 (let* ((arg (first (basic-combination-args call)))
1753 (use (lvar-uses arg)))
1754 (when (and (combination-p use)
1755 (eq (lvar-fun-name (combination-fun use))
1757 (let* ((fun (combination-lambda call))
1758 (vars (lambda-vars fun))
1759 (vals (combination-args use))
1760 (nvars (length vars))
1761 (nvals (length vals)))
1762 (cond ((> nvals nvars)
1763 (mapc #'flush-dest (subseq vals nvars))
1764 (setq vals (subseq vals 0 nvars)))
1766 (with-ir1-environment-from-node use
1767 (let ((node-prev (node-prev use)))
1768 (setf (node-prev use) nil)
1769 (setf (ctran-next node-prev) nil)
1770 (collect ((res vals))
1771 (loop for count below (- nvars nvals)
1772 for prev = node-prev then ctran
1773 for ctran = (make-ctran)
1774 and lvar = (make-lvar use)
1775 do (reference-constant prev ctran lvar nil)
1777 finally (link-node-to-previous-ctran
1779 (setq vals (res)))))))
1780 (setf (combination-args use) vals)
1781 (flush-dest (combination-fun use))
1782 (let ((fun-lvar (basic-combination-fun call)))
1783 (setf (lvar-dest fun-lvar) use)
1784 (setf (combination-fun use) fun-lvar)
1785 (flush-lvar-externally-checkable-type fun-lvar))
1786 (setf (combination-kind use) :local)
1787 (setf (functional-kind fun) :let)
1788 (flush-dest (first (basic-combination-args call)))
1791 (reoptimize-lvar (first vals)))
1792 (propagate-to-args use fun)
1793 (reoptimize-call use))
1797 ;;; (values-list (list x y z))
1802 ;;; In implementation, this is somewhat similar to
1803 ;;; CONVERT-MV-BIND-TO-LET. We grab the args of LIST and make them
1804 ;;; args of the VALUES-LIST call, flushing the old argument lvar
1805 ;;; (allowing the LIST to be flushed.)
1807 ;;; FIXME: Thus we lose possible type assertions on (LIST ...).
1808 (defoptimizer (values-list optimizer) ((list) node)
1809 (let ((use (lvar-uses list)))
1810 (when (and (combination-p use)
1811 (eq (lvar-fun-name (combination-fun use))
1814 ;; FIXME: VALUES might not satisfy an assertion on NODE-LVAR.
1815 (change-ref-leaf (lvar-uses (combination-fun node))
1816 (find-free-fun 'values "in a strange place"))
1817 (setf (combination-kind node) :full)
1818 (let ((args (combination-args use)))
1820 (setf (lvar-dest arg) node)
1821 (flush-lvar-externally-checkable-type arg))
1822 (setf (combination-args use) nil)
1824 (setf (combination-args node) args))
1827 ;;; If VALUES appears in a non-MV context, then effectively convert it
1828 ;;; to a PROG1. This allows the computation of the additional values
1829 ;;; to become dead code.
1830 (deftransform values ((&rest vals) * * :node node)
1831 (unless (lvar-single-value-p (node-lvar node))
1832 (give-up-ir1-transform))
1833 (setf (node-derived-type node)
1834 (make-short-values-type (list (single-value-type
1835 (node-derived-type node)))))
1836 (principal-lvar-single-valuify (node-lvar node))
1838 (let ((dummies (make-gensym-list (length (cdr vals)))))
1839 `(lambda (val ,@dummies)
1840 (declare (ignore ,@dummies))
1846 (defun delete-cast (cast)
1847 (declare (type cast cast))
1848 (let ((value (cast-value cast))
1849 (lvar (node-lvar cast)))
1850 (delete-filter cast lvar value)
1852 (reoptimize-lvar lvar)
1853 (when (lvar-single-value-p lvar)
1854 (note-single-valuified-lvar lvar)))
1857 (defun ir1-optimize-cast (cast &optional do-not-optimize)
1858 (declare (type cast cast))
1859 (let ((value (cast-value cast))
1860 (atype (cast-asserted-type cast)))
1861 (when (not do-not-optimize)
1862 (let ((lvar (node-lvar cast)))
1863 (when (values-subtypep (lvar-derived-type value)
1864 (cast-asserted-type cast))
1866 (return-from ir1-optimize-cast t))
1868 (when (and (listp (lvar-uses value))
1870 ;; Pathwise removing of CAST
1871 (let ((ctran (node-next cast))
1872 (dest (lvar-dest lvar))
1875 (do-uses (use value)
1876 (when (and (values-subtypep (node-derived-type use) atype)
1877 (immediately-used-p value use))
1879 (when ctran (ensure-block-start ctran))
1880 (setq next-block (first (block-succ (node-block cast))))
1881 (ensure-block-start (node-prev cast))
1882 (reoptimize-lvar lvar)
1883 (setf (lvar-%derived-type value) nil))
1884 (%delete-lvar-use use)
1885 (add-lvar-use use lvar)
1886 (unlink-blocks (node-block use) (node-block cast))
1887 (link-blocks (node-block use) next-block)
1888 (when (and (return-p dest)
1889 (basic-combination-p use)
1890 (eq (basic-combination-kind use) :local))
1892 (dolist (use (merges))
1893 (merge-tail-sets use)))))))
1895 (let* ((value-type (lvar-derived-type value))
1896 (int (values-type-intersection value-type atype)))
1897 (derive-node-type cast int)
1898 (when (eq int *empty-type*)
1899 (unless (eq value-type *empty-type*)
1901 ;; FIXME: Do it in one step.
1904 (if (cast-single-value-p cast)
1906 `(multiple-value-call #'list 'dummy)))
1909 ;; FIXME: Derived type.
1910 `(%compile-time-type-error 'dummy
1911 ',(type-specifier atype)
1912 ',(type-specifier value-type)))
1913 ;; KLUDGE: FILTER-LVAR does not work for non-returning
1914 ;; functions, so we declare the return type of
1915 ;; %COMPILE-TIME-TYPE-ERROR to be * and derive the real type
1917 (setq value (cast-value cast))
1918 (derive-node-type (lvar-uses value) *empty-type*)
1919 (maybe-terminate-block (lvar-uses value) nil)
1920 ;; FIXME: Is it necessary?
1921 (aver (null (block-pred (node-block cast))))
1922 (delete-block-lazily (node-block cast))
1923 (return-from ir1-optimize-cast)))
1924 (when (eq (node-derived-type cast) *empty-type*)
1925 (maybe-terminate-block cast nil))
1927 (when (and (cast-%type-check cast)
1928 (values-subtypep value-type
1929 (cast-type-to-check cast)))
1930 (setf (cast-%type-check cast) nil))))
1932 (unless do-not-optimize
1933 (setf (node-reoptimize cast) nil)))
1935 (deftransform make-symbol ((string) (simple-string))
1936 `(%make-symbol string))