1 /* Generate code from machine description to recognize rtl as insns.
2 Copyright (C) 1987, 1988, 1991 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21 /* This program is used to produce insn-recog.c, which contains
22 a function called `recog' plus its subroutines.
23 These functions contain a decision tree
24 that recognizes whether an rtx, the argument given to recog,
25 is a valid instruction.
27 recog returns -1 if the rtx is not valid.
28 If the rtx is valid, recog returns a nonnegative number
29 which is the insn code number for the pattern that matched.
30 This is the same as the order in the machine description of the
31 entry that matched. This number can be used as an index into various
32 insn_* tables, such as insn_template, insn_outfun, and insn_n_operands
33 (found in insn-output.c).
35 The third argument to recog is an optional pointer to an int.
36 If present, recog will accept a pattern if it matches except for
37 missing CLOBBER expressions at the end. In that case, the value
38 pointed to by the optional pointer will be set to the number of
39 CLOBBERs that need to be added (it should be initialized to zero by
40 the caller). If it is set nonzero, the caller should allocate a
41 PARALLEL of the appropriate size, copy the initial entries, and call
42 add_clobbers (found in insn-emit.c) to fill in the CLOBBERs.
44 This program also generates the function `split_insns',
45 which returns 0 if the rtl could not be split, or
46 it returns the split rtl in a SEQUENCE. */
53 static struct obstack obstack;
54 struct obstack *rtl_obstack = &obstack;
56 #define obstack_chunk_alloc xmalloc
57 #define obstack_chunk_free free
61 /* Data structure for a listhead of decision trees. The alternatives
62 to a node are kept in a doublely-linked list so we can easily add nodes
63 to the proper place when merging. */
65 struct decision_head { struct decision *first, *last; };
67 /* Data structure for decision tree for recognizing
68 legitimate instructions. */
72 int number; /* Node number, used for labels */
73 char *position; /* String denoting position in pattern */
74 RTX_CODE code; /* Code to test for or UNKNOWN to suppress */
75 char ignore_code; /* If non-zero, need not test code */
76 char ignore_mode; /* If non-zero, need not test mode */
77 int veclen; /* Length of vector, if nonzero */
78 enum machine_mode mode; /* Machine mode of node */
79 char enforce_mode; /* If non-zero, test `mode' */
80 char retest_code, retest_mode; /* See write_tree_1 */
81 int test_elt_zero_int; /* Nonzero if should test XINT (rtl, 0) */
82 int elt_zero_int; /* Required value for XINT (rtl, 0) */
83 int test_elt_one_int; /* Nonzero if should test XINT (rtl, 1) */
84 int elt_one_int; /* Required value for XINT (rtl, 1) */
85 char *tests; /* If nonzero predicate to call */
86 int pred; /* `preds' index of predicate or -1 */
87 char *c_test; /* Additional test to perform */
88 struct decision_head success; /* Nodes to test on success */
89 int insn_code_number; /* Insn number matched, if success */
90 int num_clobbers_to_add; /* Number of CLOBBERs to be added to pattern */
91 struct decision *next; /* Node to test on failure */
92 struct decision *prev; /* Node whose failure tests us */
93 struct decision *afterward; /* Node to test on success, but failure of
95 int opno; /* Operand number, if >= 0 */
96 int dupno; /* Number of operand to compare against */
97 int label_needed; /* Nonzero if label needed when writing tree */
98 int subroutine_number; /* Number of subroutine this node starts */
101 #define SUBROUTINE_THRESHOLD 50
103 static int next_subroutine_number;
105 /* We can write two types of subroutines: One for insn recognition and
106 one to split insns. This defines which type is being written. */
108 enum routine_type {RECOG, SPLIT};
110 /* Next available node number for tree nodes. */
112 static int next_number;
114 /* Next number to use as an insn_code. */
116 static int next_insn_code;
118 /* Similar, but counts all expressions in the MD file; used for
121 static int next_index;
123 /* Record the highest depth we ever have so we know how many variables to
124 allocate in each subroutine we make. */
126 static int max_depth;
128 /* This table contains a list of the rtl codes that can possibly match a
129 predicate defined in recog.c. The function `not_both_true' uses it to
130 deduce that there are no expressions that can be matches by certain pairs
131 of tree nodes. Also, if a predicate can match only one code, we can
132 hardwire that code into the node testing the predicate. */
134 static struct pred_table
137 RTX_CODE codes[NUM_RTX_CODE];
139 = {{"general_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
140 LABEL_REF, SUBREG, REG, MEM}},
141 #ifdef PREDICATE_CODES
144 {"address_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
145 LABEL_REF, SUBREG, REG, MEM, PLUS, MINUS, MULT}},
146 {"register_operand", {SUBREG, REG}},
147 {"scratch_operand", {SCRATCH, REG}},
148 {"immediate_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
150 {"const_int_operand", {CONST_INT}},
151 {"const_double_operand", {CONST_INT, CONST_DOUBLE}},
152 {"nonimmediate_operand", {SUBREG, REG, MEM}},
153 {"nonmemory_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
154 LABEL_REF, SUBREG, REG}},
155 {"push_operand", {MEM}},
156 {"memory_operand", {SUBREG, MEM}},
157 {"indirect_operand", {SUBREG, MEM}},
158 {"comparison_operation", {EQ, NE, LE, LT, GE, LT, LEU, LTU, GEU, GTU}},
159 {"mode_independent_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
160 LABEL_REF, SUBREG, REG, MEM}}};
162 #define NUM_KNOWN_PREDS (sizeof preds / sizeof preds[0])
164 static int try_merge_1 ();
165 static int no_same_mode ();
166 static int same_codes ();
167 static int same_modes ();
169 static struct decision *add_to_sequence ();
170 static struct decision_head merge_trees ();
171 static struct decision *try_merge_2 ();
172 static void write_subroutine ();
173 static void print_code ();
174 static void clear_codes ();
175 static void clear_modes ();
176 static void change_state ();
177 static void write_tree ();
178 static char *copystr ();
179 static char *concat ();
180 static void fatal ();
182 static void mybzero ();
183 static void mybcopy ();
185 /* Construct and return a sequence of decisions
186 that will recognize INSN.
188 TYPE says what type of routine we are recognizing (RECOG or SPLIT). */
190 static struct decision_head
191 make_insn_sequence (insn, type)
193 enum routine_type type;
196 char *c_test = XSTR (insn, type == RECOG ? 2 : 1);
197 struct decision *last;
198 struct decision_head head;
200 if (XVECLEN (insn, type == RECOG) == 1)
201 x = XVECEXP (insn, type == RECOG, 0);
204 x = rtx_alloc (PARALLEL);
205 XVEC (x, 0) = XVEC (insn, type == RECOG);
206 PUT_MODE (x, VOIDmode);
209 last = add_to_sequence (x, &head, "");
212 last->c_test = c_test;
213 last->insn_code_number = next_insn_code;
214 last->num_clobbers_to_add = 0;
216 /* If this is not a DEFINE_SPLIT and X is a PARALLEL, see if it ends with a
217 group of CLOBBERs of (hard) registers or MATCH_SCRATCHes. If so, set up
218 to recognize the pattern without these CLOBBERs. */
220 if (type == RECOG && GET_CODE (x) == PARALLEL)
224 for (i = XVECLEN (x, 0); i > 0; i--)
225 if (GET_CODE (XVECEXP (x, 0, i - 1)) != CLOBBER
226 || (GET_CODE (XEXP (XVECEXP (x, 0, i - 1), 0)) != REG
227 && GET_CODE (XEXP (XVECEXP (x, 0, i - 1), 0)) != MATCH_SCRATCH))
230 if (i != XVECLEN (x, 0))
233 struct decision_head clobber_head;
236 new = XVECEXP (x, 0, 0);
241 new = rtx_alloc (PARALLEL);
242 XVEC (new, 0) = rtvec_alloc (i);
243 for (j = i - 1; j >= 0; j--)
244 XVECEXP (new, 0, j) = XVECEXP (x, 0, j);
247 last = add_to_sequence (new, &clobber_head, "");
250 last->c_test = c_test;
251 last->insn_code_number = next_insn_code;
252 last->num_clobbers_to_add = XVECLEN (x, 0) - i;
254 head = merge_trees (head, clobber_head);
261 /* Define the subroutine we will call below and emit in genemit. */
262 printf ("extern rtx gen_split_%d ();\n", last->insn_code_number);
267 /* Create a chain of nodes to verify that an rtl expression matches
270 LAST is a pointer to the listhead in the previous node in the chain (or
271 in the calling function, for the first node).
273 POSITION is the string representing the current position in the insn.
275 A pointer to the final node in the chain is returned. */
277 static struct decision *
278 add_to_sequence (pattern, last, position)
280 struct decision_head *last;
283 register RTX_CODE code;
284 register struct decision *new
285 = (struct decision *) xmalloc (sizeof (struct decision));
286 struct decision *this;
290 int depth = strlen (position);
293 if (depth > max_depth)
296 new->number = next_number++;
297 new->position = copystr (position);
298 new->ignore_code = 0;
299 new->ignore_mode = 0;
300 new->enforce_mode = 1;
301 new->retest_code = new->retest_mode = 0;
303 new->test_elt_zero_int = 0;
304 new->test_elt_one_int = 0;
305 new->elt_zero_int = 0;
306 new->elt_one_int = 0;
310 new->success.first = new->success.last = 0;
311 new->insn_code_number = -1;
312 new->num_clobbers_to_add = 0;
318 new->label_needed = 0;
319 new->subroutine_number = 0;
323 last->first = last->last = new;
325 newpos = (char *) alloca (depth + 2);
326 strcpy (newpos, position);
327 newpos[depth + 1] = 0;
331 new->mode = GET_MODE (pattern);
332 new->code = code = GET_CODE (pattern);
340 new->opno = XINT (pattern, 0);
341 new->code = (code == MATCH_PARALLEL ? PARALLEL : UNKNOWN);
342 new->enforce_mode = 0;
344 if (code == MATCH_SCRATCH)
345 new->tests = "scratch_operand";
347 new->tests = XSTR (pattern, 1);
349 if (*new->tests == 0)
352 /* See if we know about this predicate and save its number. If we do,
353 and it only accepts one code, note that fact. The predicate
354 `const_int_operand' only tests for a CONST_INT, so if we do so we
355 can avoid calling it at all.
357 Finally, if we know that the predicate does not allow CONST_INT, we
358 know that the only way the predicate can match is if the modes match
359 (here we use the kluge of relying on the fact that "address_operand"
360 accepts CONST_INT; otherwise, it would have to be a special case),
361 so we can test the mode (but we need not). This fact should
362 considerably simplify the generated code. */
365 for (i = 0; i < NUM_KNOWN_PREDS; i++)
366 if (! strcmp (preds[i].name, new->tests))
369 int allows_const_int = 0;
373 if (preds[i].codes[1] == 0 && new->code == UNKNOWN)
375 new->code = preds[i].codes[0];
376 if (! strcmp ("const_int_operand", new->tests))
377 new->tests = 0, new->pred = -1;
380 for (j = 0; j < NUM_RTX_CODE && preds[i].codes[j] != 0; j++)
381 if (preds[i].codes[j] == CONST_INT)
382 allows_const_int = 1;
384 if (! allows_const_int)
385 new->enforce_mode = new->ignore_mode= 1;
390 if (code == MATCH_OPERATOR || code == MATCH_PARALLEL)
392 for (i = 0; i < XVECLEN (pattern, 2); i++)
394 newpos[depth] = i + (code == MATCH_OPERATOR ? '0': 'a');
395 new = add_to_sequence (XVECEXP (pattern, 2, i),
396 &new->success, newpos);
399 this->success.first->enforce_mode = 0;
405 new->opno = XINT (pattern, 0);
406 new->dupno = XINT (pattern, 0);
409 for (i = 0; i < XVECLEN (pattern, 1); i++)
411 newpos[depth] = i + '0';
412 new = add_to_sequence (XVECEXP (pattern, 1, i),
413 &new->success, newpos);
415 this->success.first->enforce_mode = 0;
419 new->dupno = XINT (pattern, 0);
421 new->enforce_mode = 0;
425 pattern = XEXP (pattern, 0);
430 new = add_to_sequence (SET_DEST (pattern), &new->success, newpos);
431 this->success.first->enforce_mode = 1;
433 new = add_to_sequence (SET_SRC (pattern), &new->success, newpos);
435 /* If set are setting CC0 from anything other than a COMPARE, we
436 must enforce the mode so that we do not produce ambiguous insns. */
437 if (GET_CODE (SET_DEST (pattern)) == CC0
438 && GET_CODE (SET_SRC (pattern)) != COMPARE)
439 this->success.first->enforce_mode = 1;
444 case STRICT_LOW_PART:
446 new = add_to_sequence (XEXP (pattern, 0), &new->success, newpos);
447 this->success.first->enforce_mode = 1;
451 this->test_elt_one_int = 1;
452 this->elt_one_int = XINT (pattern, 1);
454 new = add_to_sequence (XEXP (pattern, 0), &new->success, newpos);
455 this->success.first->enforce_mode = 1;
461 new = add_to_sequence (XEXP (pattern, 0), &new->success, newpos);
462 this->success.first->enforce_mode = 1;
464 new = add_to_sequence (XEXP (pattern, 1), &new->success, newpos);
466 new = add_to_sequence (XEXP (pattern, 2), &new->success, newpos);
469 case EQ: case NE: case LE: case LT: case GE: case GT:
470 case LEU: case LTU: case GEU: case GTU:
471 /* If the first operand is (cc0), we don't have to do anything
473 if (GET_CODE (XEXP (pattern, 0)) == CC0)
476 /* ... fall through ... */
479 /* Enforce the mode on the first operand to avoid ambiguous insns. */
481 new = add_to_sequence (XEXP (pattern, 0), &new->success, newpos);
482 this->success.first->enforce_mode = 1;
484 new = add_to_sequence (XEXP (pattern, 1), &new->success, newpos);
488 fmt = GET_RTX_FORMAT (code);
489 len = GET_RTX_LENGTH (code);
490 for (i = 0; i < len; i++)
492 newpos[depth] = '0' + i;
493 if (fmt[i] == 'e' || fmt[i] == 'u')
494 new = add_to_sequence (XEXP (pattern, i), &new->success, newpos);
495 else if (fmt[i] == 'i' && i == 0)
497 this->test_elt_zero_int = 1;
498 this->elt_zero_int = XINT (pattern, i);
500 else if (fmt[i] == 'i' && i == 1)
502 this->test_elt_one_int = 1;
503 this->elt_one_int = XINT (pattern, i);
505 else if (fmt[i] == 'E')
508 /* We do not handle a vector appearing as other than
509 the first item, just because nothing uses them
510 and by handling only the special case
511 we can use one element in newpos for either
512 the item number of a subexpression
513 or the element number in a vector. */
516 this->veclen = XVECLEN (pattern, i);
517 for (j = 0; j < XVECLEN (pattern, i); j++)
519 newpos[depth] = 'a' + j;
520 new = add_to_sequence (XVECEXP (pattern, i, j),
521 &new->success, newpos);
524 else if (fmt[i] != '0')
530 /* Return 1 if we can prove that there is no RTL that can match both
531 D1 and D2. Otherwise, return 0 (it may be that there is an RTL that
532 can match both or just that we couldn't prove there wasn't such an RTL).
534 TOPLEVEL is non-zero if we are to only look at the top level and not
535 recursively descend. */
538 not_both_true (d1, d2, toplevel)
539 struct decision *d1, *d2;
542 struct decision *p1, *p2;
544 /* If they are both to test modes and the modes are different, they aren't
545 both true. Similarly for codes, integer elements, and vector lengths. */
547 if ((d1->enforce_mode && d2->enforce_mode
548 && d1->mode != VOIDmode && d2->mode != VOIDmode && d1->mode != d2->mode)
549 || (d1->code != UNKNOWN && d2->code != UNKNOWN && d1->code != d2->code)
550 || (d1->test_elt_zero_int && d2->test_elt_zero_int
551 && d1->elt_zero_int != d2->elt_zero_int)
552 || (d1->test_elt_one_int && d2->test_elt_one_int
553 && d1->elt_one_int != d2->elt_one_int)
554 || (d1->veclen && d2->veclen && d1->veclen != d2->veclen))
557 /* If either is a wild-card MATCH_OPERAND without a predicate, it can match
558 absolutely anything, so we can't say that no intersection is possible.
559 This case is detected by having a zero TESTS field with a code of
562 if ((d1->tests == 0 && d1->code == UNKNOWN)
563 || (d2->tests == 0 && d2->code == UNKNOWN))
566 /* If either has a predicate that we know something about, set things up so
567 that D1 is the one that always has a known predicate. Then see if they
568 have any codes in common. */
570 if (d1->pred >= 0 || d2->pred >= 0)
575 p1 = d1, d1 = d2, d2 = p1;
577 /* If D2 tests an explicit code, see if it is in the list of valid codes
578 for D1's predicate. */
579 if (d2->code != UNKNOWN)
581 for (i = 0; i < NUM_RTX_CODE && preds[d1->pred].codes[i]; i++)
582 if (preds[d1->pred].codes[i] == d2->code)
585 if (preds[d1->pred].codes[i] == 0)
589 /* Otherwise see if the predicates have any codes in common. */
591 else if (d2->pred >= 0)
593 for (i = 0; i < NUM_RTX_CODE && preds[d1->pred].codes[i]; i++)
595 for (j = 0; j < NUM_RTX_CODE; j++)
596 if (preds[d2->pred].codes[j] == 0
597 || preds[d2->pred].codes[j] == preds[d1->pred].codes[i])
600 if (preds[d2->pred].codes[j] != 0)
604 if (preds[d1->pred].codes[i] == 0)
609 /* If we got here, we can't prove that D1 and D2 cannot both be true.
610 If we are only to check the top level, return 0. Otherwise, see if
611 we can prove that all choices in both successors are mutually
612 exclusive. If either does not have any successors, we can't prove
613 they can't both be true. */
615 if (toplevel || d1->success.first == 0 || d2->success.first == 0)
618 for (p1 = d1->success.first; p1; p1 = p1->next)
619 for (p2 = d2->success.first; p2; p2 = p2->next)
620 if (! not_both_true (p1, p2, 0))
626 /* Assuming that we can reorder all the alternatives at a specific point in
627 the tree (see discussion in merge_trees), we would prefer an ordering of
628 nodes where groups of consecutive nodes test the same mode and, within each
629 mode, groups of nodes test the same code. With this order, we can
630 construct nested switch statements, the inner one to test the code and
631 the outer one to test the mode.
633 We would like to list nodes testing for specific codes before those
634 that test predicates to avoid unnecessary function calls. Similarly,
635 tests for specific modes should preceed nodes that allow any mode.
637 This function returns the merit (with 0 being the best) of inserting
638 a test involving the specified MODE and CODE after node P. If P is
639 zero, we are to determine the merit of inserting the test at the front
643 position_merit (p, mode, code)
645 enum machine_mode mode;
648 enum machine_mode p_mode;
650 /* The only time the front of the list is anything other than the worst
651 position is if we are testing a mode that isn't VOIDmode. */
653 return mode == VOIDmode ? 3 : 2;
655 p_mode = p->enforce_mode ? p->mode : VOIDmode;
657 /* The best case is if the codes and modes both match. */
658 if (p_mode == mode && p->code== code)
661 /* If the codes don't match, the next best case is if the modes match.
662 In that case, the best position for this node depends on whether
663 we are testing for a specific code or not. If we are, the best place
664 is after some other test for an explicit code and our mode or after
665 the last test in the previous mode if every test in our mode is for
668 If we are testing for UNKNOWN, then the next best case is at the end of
672 && ((p_mode == mode && p->code != UNKNOWN)
673 || (p_mode != mode && p->next
674 && (p->next->enforce_mode ? p->next->mode : VOIDmode) == mode
675 && (p->next->code == UNKNOWN))))
676 || (code == UNKNOWN && p_mode == mode
678 || (p->next->enforce_mode ? p->next->mode : VOIDmode) != mode)))
681 /* The third best case occurs when nothing is testing MODE. If MODE
682 is not VOIDmode, then the third best case is after something of any
683 mode that is not VOIDmode. If we are testing VOIDmode, the third best
684 place is the end of the list. */
687 && ((mode != VOIDmode && p_mode != VOIDmode)
688 || (mode == VOIDmode && p->next == 0)))
691 /* Otherwise, we have the worst case. */
695 /* Merge two decision tree listheads OLDH and ADDH,
696 modifying OLDH destructively, and return the merged tree. */
698 static struct decision_head
699 merge_trees (oldh, addh)
700 register struct decision_head oldh, addh;
702 struct decision *add, *next;
710 /* If we are adding things at different positions, something is wrong. */
711 if (strcmp (oldh.first->position, addh.first->position))
714 for (add = addh.first; add; add = next)
716 enum machine_mode add_mode = add->enforce_mode ? add->mode : VOIDmode;
717 struct decision *best_position = 0;
719 struct decision *old;
723 /* The semantics of pattern matching state that the tests are done in
724 the order given in the MD file so that if an insn matches two
725 patterns, the first one will be used. However, in practice, most,
726 if not all, patterns are unambiguous so that their order is
727 independent. In that case, we can merge identical tests and
728 group all similar modes and codes together.
730 Scan starting from the end of OLDH until we reach a point
731 where we reach the head of the list or where we pass a pattern
732 that could also be true if NEW is true. If we find an identical
733 pattern, we can merge them. Also, record the last node that tests
734 the same code and mode and the last one that tests just the same mode.
736 If we have no match, place NEW after the closest match we found. */
738 for (old = oldh.last; old; old = old->prev)
742 /* If we don't have anything to test except an additional test,
743 do not consider the two nodes equal. If we did, the test below
744 would cause an infinite recursion. */
745 if (old->tests == 0 && old->test_elt_zero_int == 0
746 && old->test_elt_one_int == 0 && old->veclen == 0
747 && old->dupno == -1 && old->mode == VOIDmode
748 && old->code == UNKNOWN
749 && (old->c_test != 0 || add->c_test != 0))
752 else if ((old->tests == add->tests
753 || (old->pred >= 0 && old->pred == add->pred)
754 || (old->tests && add->tests
755 && !strcmp (old->tests, add->tests)))
756 && old->test_elt_zero_int == add->test_elt_zero_int
757 && old->elt_zero_int == add->elt_zero_int
758 && old->test_elt_one_int == add->test_elt_one_int
759 && old->elt_one_int == add->elt_one_int
760 && old->veclen == add->veclen
761 && old->dupno == add->dupno
762 && old->opno == add->opno
763 && old->code == add->code
764 && old->enforce_mode == add->enforce_mode
765 && old->mode == add->mode)
767 /* If the additional test is not the same, split both nodes
768 into nodes that just contain all things tested before the
769 additional test and nodes that contain the additional test
770 and actions when it is true. This optimization is important
771 because of the case where we have almost identical patterns
772 with different tests on target flags. */
774 if (old->c_test != add->c_test
775 && ! (old->c_test && add->c_test
776 && !strcmp (old->c_test, add->c_test)))
778 if (old->insn_code_number >= 0 || old->opno >= 0)
780 struct decision *split
781 = (struct decision *) xmalloc (sizeof (struct decision));
783 mybcopy (old, split, sizeof (struct decision));
785 old->success.first = old->success.last = split;
788 old->insn_code_number = -1;
789 old->num_clobbers_to_add = 0;
791 split->number = next_number++;
792 split->next = split->prev = 0;
793 split->mode = VOIDmode;
794 split->code = UNKNOWN;
796 split->test_elt_zero_int = 0;
797 split->test_elt_one_int = 0;
802 if (add->insn_code_number >= 0 || add->opno >= 0)
804 struct decision *split
805 = (struct decision *) xmalloc (sizeof (struct decision));
807 mybcopy (add, split, sizeof (struct decision));
809 add->success.first = add->success.last = split;
812 add->insn_code_number = -1;
813 add->num_clobbers_to_add = 0;
815 split->number = next_number++;
816 split->next = split->prev = 0;
817 split->mode = VOIDmode;
818 split->code = UNKNOWN;
820 split->test_elt_zero_int = 0;
821 split->test_elt_one_int = 0;
827 if (old->insn_code_number >= 0 && add->insn_code_number >= 0)
829 /* If one node is for a normal insn and the second is
830 for the base insn with clobbers stripped off, the
831 second node should be ignored. */
833 if (old->num_clobbers_to_add == 0
834 && add->num_clobbers_to_add > 0)
835 /* Nothing to do here. */
837 else if (old->num_clobbers_to_add > 0
838 && add->num_clobbers_to_add == 0)
840 /* In this case, replace OLD with ADD. */
841 old->insn_code_number = add->insn_code_number;
842 old->num_clobbers_to_add = 0;
845 fatal ("Two actions at one point in tree");
848 if (old->insn_code_number == -1)
849 old->insn_code_number = add->insn_code_number;
850 old->success = merge_trees (old->success, add->success);
855 /* Unless we have already found the best possible insert point,
856 see if this position is better. If so, record it. */
859 && ((our_merit = position_merit (old, add_mode, add->code))
861 best_merit = our_merit, best_position = old;
863 if (! not_both_true (old, add, 0))
867 /* If ADD was duplicate, we are done. */
871 /* Otherwise, find the best place to insert ADD. Normally this is
872 BEST_POSITION. However, if we went all the way to the top of
873 the list, it might be better to insert at the top. */
875 if (best_position == 0)
878 if (old == 0 && position_merit (0, add_mode, add->code) < best_merit)
881 add->next = oldh.first;
882 oldh.first->prev = add;
888 add->prev = best_position;
889 add->next = best_position->next;
890 best_position->next = add;
891 if (best_position == oldh.last)
894 add->next->prev = add;
901 /* Count the number of subnodes of HEAD. If the number is high enough,
902 make the first node in HEAD start a separate subroutine in the C code
905 TYPE gives the type of routine we are writing.
907 INITIAL is non-zero if this is the highest-level node. We never write
911 break_out_subroutines (head, type, initial)
912 struct decision_head head;
913 enum routine_type type;
917 struct decision *node, *sub;
919 for (sub = head.first; sub; sub = sub->next)
920 size += 1 + break_out_subroutines (sub->success, type, 0);
922 if (size > SUBROUTINE_THRESHOLD && ! initial)
924 head.first->subroutine_number = ++next_subroutine_number;
925 write_subroutine (head.first, type);
931 /* Write out a subroutine of type TYPE to do comparisons starting at node
935 write_subroutine (tree, type)
936 struct decision *tree;
937 enum routine_type type;
942 printf ("rtx\nsplit");
944 printf ("int\nrecog");
946 if (tree != 0 && tree->subroutine_number > 0)
947 printf ("_%d", tree->subroutine_number);
948 else if (type == SPLIT)
951 printf (" (x0, insn");
953 printf (", pnum_clobbers");
956 printf (" register rtx x0;\n rtx insn;\n");
958 printf (" int *pnum_clobbers;\n");
961 printf (" register rtx *ro = &recog_operand[0];\n");
963 printf (" register rtx ");
964 for (i = 1; i < max_depth; i++)
967 printf ("x%d;\n", max_depth);
968 printf (" %s tem;\n", type == SPLIT ? "rtx" : "int");
969 write_tree (tree, "", 0, 1, type);
970 printf (" ret0: return %d;\n}\n\n", type == SPLIT ? 0 : -1);
973 /* This table is used to indent the recog_* functions when we are inside
974 conditions or switch statements. We only support small indentations
975 and always indent at least two spaces. */
977 static char *indents[]
978 = {" ", " ", " ", " ", " ", " ", " ", " ",
979 "\t", "\t ", "\t ", "\t ", "\t ", "\t ", "\t ",
980 "\t\t", "\t\t ", "\t\t ", "\t\t ", "\t\t ", "\t\t "};
982 /* Write out C code to perform the decisions in TREE for a subroutine of
983 type TYPE. If all of the choices fail, branch to node AFTERWARD, if
984 non-zero, otherwise return. PREVPOS is the position of the node that
985 branched to this test.
987 When we merged all alternatives, we tried to set up a convenient order.
988 Specifically, tests involving the same mode are all grouped together,
989 followed by a group that does not contain a mode test. Within each group
990 of the same mode, we also group tests with the same code, followed by a
991 group that does not test a code.
993 Occasionally, we cannot arbitarily reorder the tests so that multiple
994 sequence of groups as described above are present.
996 We generate two nested switch statements, the outer statement for
997 testing modes, and the inner switch for testing RTX codes. It is
998 not worth optimizing cases when only a small number of modes or
999 codes is tested, since the compiler can do that when compiling the
1000 resulting function. We do check for when every test is the same mode
1004 write_tree_1 (tree, prevpos, afterward, type)
1005 struct decision *tree;
1007 struct decision *afterward;
1008 enum routine_type type;
1010 register struct decision *p, *p1;
1011 register int depth = tree ? strlen (tree->position) : 0;
1012 enum machine_mode switch_mode = VOIDmode;
1013 RTX_CODE switch_code = UNKNOWN;
1015 char modemap[NUM_MACHINE_MODES];
1016 char codemap[NUM_RTX_CODE];
1020 /* One tricky area is what is the exact state when we branch to a
1021 node's label. There are two cases where we branch: when looking at
1022 successors to a node, or when a set of tests fails.
1024 In the former case, we are always branching to the first node in a
1025 decision list and we want all required tests to be performed. We
1026 put the labels for such nodes in front of any switch or test statements.
1027 These branches are done without updating the position to that of the
1030 In the latter case, we are branching to a node that is not the first
1031 node in a decision list. We have already checked that it is possible
1032 for both the node we originally tested at this level and the node we
1033 are branching to to be both match some pattern. That means that they
1034 usually will be testing the same mode and code. So it is normally safe
1035 for such labels to be inside switch statements, since the tests done
1036 by virtue of arriving at that label will usually already have been
1037 done. The exception is a branch from a node that does not test a
1038 mode or code to one that does. In such cases, we set the `retest_mode'
1039 or `retest_code' flags. That will ensure that we start a new switch
1040 at that position and put the label before the switch.
1042 The branches in the latter case must set the position to that of the
1047 if (tree && tree->subroutine_number == 0)
1049 printf (" L%d:\n", tree->number);
1050 tree->label_needed = 0;
1055 change_state (prevpos, tree->position, 2);
1056 prevpos = tree->position;
1059 for (p = tree; p; p = p->next)
1061 enum machine_mode mode = p->enforce_mode ? p->mode : VOIDmode;
1063 int wrote_bracket = 0;
1066 if (p->success.first == 0 && p->insn_code_number < 0)
1069 /* Find the next alternative to p that might be true when p is true.
1070 Test that one next if p's successors fail. */
1072 for (p1 = p->next; p1 && not_both_true (p, p1, 1); p1 = p1->next)
1078 if (mode == VOIDmode && p1->enforce_mode && p1->mode != VOIDmode)
1079 p1->retest_mode = 1;
1080 if (p->code == UNKNOWN && p1->code != UNKNOWN)
1081 p1->retest_code = 1;
1082 p1->label_needed = 1;
1085 /* If we have a different code or mode than the last node and
1086 are in a switch on codes, we must either end the switch or
1087 go to another case. We must also end the switch if this
1088 node needs a label and to retest either the mode or code. */
1090 if (switch_code != UNKNOWN
1091 && (switch_code != p->code || switch_mode != mode
1092 || (p->label_needed && (p->retest_mode || p->retest_code))))
1094 enum rtx_code code = p->code;
1096 /* If P is testing a predicate that we know about and we haven't
1097 seen any of the codes that are valid for the predicate, we
1098 can write a series of "case" statement, one for each possible
1099 code. Since we are already in a switch, these redundant tests
1100 are very cheap and will reduce the number of predicate called. */
1104 for (i = 0; i < NUM_RTX_CODE && preds[p->pred].codes[i]; i++)
1105 if (codemap[(int) preds[p->pred].codes[i]])
1108 if (preds[p->pred].codes[i] == 0)
1109 code = MATCH_OPERAND;
1112 if (code == UNKNOWN || codemap[(int) code]
1113 || switch_mode != mode
1114 || (p->label_needed && (p->retest_mode || p->retest_code)))
1116 printf ("%s}\n", indents[indent - 2]);
1117 switch_code = UNKNOWN;
1123 printf ("%sbreak;\n", indents[indent]);
1125 if (code == MATCH_OPERAND)
1127 for (i = 0; i < NUM_RTX_CODE && preds[p->pred].codes[i]; i++)
1129 printf ("%scase ", indents[indent - 2]);
1130 print_code (preds[p->pred].codes[i]);
1132 codemap[(int) preds[p->pred].codes[i]] = 1;
1137 printf ("%scase ", indents[indent - 2]);
1140 codemap[(int) p->code] = 1;
1149 /* If we were previously in a switch on modes and now have a different
1150 mode, end at least the case, and maybe end the switch if we are
1151 not testing a mode or testing a mode whose case we already saw. */
1153 if (switch_mode != VOIDmode
1154 && (switch_mode != mode || (p->label_needed && p->retest_mode)))
1156 if (mode == VOIDmode || modemap[(int) mode]
1157 || (p->label_needed && p->retest_mode))
1159 printf ("%s}\n", indents[indent - 2]);
1160 switch_mode = VOIDmode;
1166 printf (" break;\n");
1167 printf (" case %smode:\n", GET_MODE_NAME (mode));
1169 modemap[(int) mode] = 1;
1175 /* If we are about to write dead code, something went wrong. */
1176 if (! p->label_needed && uncond)
1179 /* If we need a label and we will want to retest the mode or code at
1180 that label, write the label now. We have already ensured that
1181 things will be valid for the test. */
1183 if (p->label_needed && (p->retest_mode || p->retest_code))
1185 printf ("%sL%d:\n", indents[indent - 2], p->number);
1186 p->label_needed = 0;
1191 /* If we are not in any switches, see if we can shortcut things
1192 by checking for identical modes and codes. */
1194 if (switch_mode == VOIDmode && switch_code == UNKNOWN)
1196 /* If p and its alternatives all want the same mode,
1197 reject all others at once, first, then ignore the mode. */
1199 if (mode != VOIDmode && p->next && same_modes (p, mode))
1201 printf (" if (GET_MODE (x%d) != %smode)\n",
1202 depth, GET_MODE_NAME (p->mode));
1206 change_state (p->position, afterward->position, 6);
1207 printf (" goto L%d;\n }\n", afterward->number);
1210 printf (" goto ret0;\n");
1215 /* If p and its alternatives all want the same code,
1216 reject all others at once, first, then ignore the code. */
1218 if (p->code != UNKNOWN && p->next && same_codes (p, p->code))
1220 printf (" if (GET_CODE (x%d) != ", depth);
1221 print_code (p->code);
1226 change_state (p->position, afterward->position, indent + 4);
1227 printf (" goto L%d;\n }\n", afterward->number);
1230 printf (" goto ret0;\n");
1235 /* If we are not in a mode switch and we are testing for a specific
1236 mode, start a mode switch unless we have just one node or the next
1237 node is not testing a mode (we have already tested for the case of
1238 more than one mode, but all of the same mode). */
1240 if (switch_mode == VOIDmode && mode != VOIDmode && p->next != 0
1241 && p->next->enforce_mode && p->next->mode != VOIDmode)
1243 mybzero (modemap, sizeof modemap);
1244 printf ("%sswitch (GET_MODE (x%d))\n", indents[indent], depth);
1245 printf ("%s{\n", indents[indent + 2]);
1247 printf ("%scase %smode:\n", indents[indent - 2],
1248 GET_MODE_NAME (mode));
1249 modemap[(int) mode] = 1;
1253 /* Similarly for testing codes. */
1255 if (switch_code == UNKNOWN && p->code != UNKNOWN && ! p->ignore_code
1256 && p->next != 0 && p->next->code != UNKNOWN)
1258 mybzero (codemap, sizeof codemap);
1259 printf ("%sswitch (GET_CODE (x%d))\n", indents[indent], depth);
1260 printf ("%s{\n", indents[indent + 2]);
1262 printf ("%scase ", indents[indent - 2]);
1263 print_code (p->code);
1265 codemap[(int) p->code] = 1;
1266 switch_code = p->code;
1269 /* Now that most mode and code tests have been done, we can write out
1270 a label for an inner node, if we haven't already. */
1271 if (p->label_needed)
1272 printf ("%sL%d:\n", indents[indent - 2], p->number);
1274 inner_indent = indent;
1276 /* The only way we can have to do a mode or code test here is if
1277 this node needs such a test but is the only node to be tested.
1278 In that case, we won't have started a switch. Note that this is
1279 the only way the switch and test modes can disagree. */
1281 if ((mode != switch_mode && ! p->ignore_mode)
1282 || (p->code != switch_code && p->code != UNKNOWN && ! p->ignore_code)
1283 || p->test_elt_zero_int || p->test_elt_one_int || p->veclen
1284 || p->dupno >= 0 || p->tests || p->num_clobbers_to_add)
1286 printf ("%sif (", indents[indent]);
1288 if (mode != switch_mode && ! p->ignore_mode)
1289 printf ("GET_MODE (x%d) == %smode && ",
1290 depth, GET_MODE_NAME (mode));
1291 if (p->code != switch_code && p->code != UNKNOWN && ! p->ignore_code)
1293 printf ("GET_CODE (x%d) == ", depth);
1294 print_code (p->code);
1298 if (p->test_elt_zero_int)
1299 printf ("XINT (x%d, 0) == %d && ", depth, p->elt_zero_int);
1300 if (p->test_elt_one_int)
1301 printf ("XINT (x%d, 1) == %d && ", depth, p->elt_one_int);
1303 printf ("XVECLEN (x%d, 0) == %d && ", depth, p->veclen);
1305 printf ("rtx_equal_p (x%d, ro[%d]) && ", depth, p->dupno);
1306 if (p->num_clobbers_to_add)
1307 printf ("pnum_clobbers != 0 && ");
1309 printf ("%s (x%d, %smode)", p->tests, depth,
1310 GET_MODE_NAME (p->mode));
1320 need_bracket = ! uncond;
1326 printf ("%s{\n", indents[inner_indent]);
1332 printf ("%sro[%d] = x%d;\n", indents[inner_indent], p->opno, depth);
1337 printf ("%sif (%s)\n", indents[inner_indent], p->c_test);
1343 if (p->insn_code_number >= 0)
1346 printf ("%sreturn gen_split_%d (operands);\n",
1347 indents[inner_indent], p->insn_code_number);
1350 if (p->num_clobbers_to_add)
1354 printf ("%s{\n", indents[inner_indent]);
1358 printf ("%s*pnum_clobbers = %d;\n",
1359 indents[inner_indent], p->num_clobbers_to_add);
1360 printf ("%sreturn %d;\n",
1361 indents[inner_indent], p->insn_code_number);
1366 printf ("%s}\n", indents[inner_indent]);
1370 printf ("%sreturn %d;\n",
1371 indents[inner_indent], p->insn_code_number);
1375 printf ("%sgoto L%d;\n", indents[inner_indent],
1376 p->success.first->number);
1379 printf ("%s}\n", indents[inner_indent - 2]);
1382 /* We have now tested all alternatives. End any switches we have open
1383 and branch to the alternative node unless we know that we can't fall
1384 through to the branch. */
1386 if (switch_code != UNKNOWN)
1388 printf ("%s}\n", indents[indent - 2]);
1393 if (switch_mode != VOIDmode)
1395 printf ("%s}\n", indents[indent - 2]);
1408 change_state (prevpos, afterward->position, 2);
1409 printf (" goto L%d;\n", afterward->number);
1412 printf (" goto ret0;\n");
1420 for (p1 = GET_RTX_NAME (code); *p1; p1++)
1422 if (*p1 >= 'a' && *p1 <= 'z')
1423 putchar (*p1 + 'A' - 'a');
1430 same_codes (p, code)
1431 register struct decision *p;
1432 register RTX_CODE code;
1434 for (; p; p = p->next)
1435 if (p->code != code)
1443 register struct decision *p;
1445 for (; p; p = p->next)
1450 same_modes (p, mode)
1451 register struct decision *p;
1452 register enum machine_mode mode;
1454 for (; p; p = p->next)
1455 if ((p->enforce_mode ? p->mode : VOIDmode) != mode)
1463 register struct decision *p;
1465 for (; p; p = p->next)
1466 p->enforce_mode = 0;
1469 /* Write out the decision tree starting at TREE for a subroutine of type TYPE.
1471 PREVPOS is the position at the node that branched to this node.
1473 INITIAL is nonzero if this is the first node we are writing in a subroutine.
1475 If all nodes are false, branch to the node AFTERWARD. */
1478 write_tree (tree, prevpos, afterward, initial, type)
1479 struct decision *tree;
1481 struct decision *afterward;
1483 enum routine_type type;
1485 register struct decision *p;
1486 char *name_prefix = (type == SPLIT ? "split" : "recog");
1487 char *call_suffix = (type == SPLIT ? "" : ", pnum_clobbers");
1489 if (! initial && tree->subroutine_number > 0)
1491 printf (" L%d:\n", tree->number);
1495 printf (" tem = %s_%d (x0, insn%s);\n",
1496 name_prefix, tree->subroutine_number, call_suffix);
1497 printf (" if (tem >= 0) return tem;\n");
1498 change_state (tree->position, afterward->position, 2);
1499 printf (" goto L%d;\n", afterward->number);
1502 printf (" return %s_%d (x0, insn%s);\n",
1503 name_prefix, tree->subroutine_number, call_suffix);
1507 write_tree_1 (tree, prevpos, afterward, type);
1509 for (p = tree; p; p = p->next)
1510 if (p->success.first)
1511 write_tree (p->success.first, p->position,
1512 p->afterward ? p->afterward : afterward, 0, type);
1516 /* Assuming that the state of argument is denoted by OLDPOS, take whatever
1517 actions are necessary to move to NEWPOS.
1519 INDENT says how many blanks to place at the front of lines. */
1522 change_state (oldpos, newpos, indent)
1527 int odepth = strlen (oldpos);
1529 int ndepth = strlen (newpos);
1531 /* Pop up as many levels as necessary. */
1533 while (strncmp (oldpos, newpos, depth))
1536 /* Go down to desired level. */
1538 while (depth < ndepth)
1540 if (newpos[depth] >= 'a' && newpos[depth] <= 'z')
1541 printf ("%sx%d = XVECEXP (x%d, 0, %d);\n",
1542 indents[indent], depth + 1, depth, newpos[depth] - 'a');
1544 printf ("%sx%d = XEXP (x%d, %c);\n",
1545 indents[indent], depth + 1, depth, newpos[depth]);
1559 tem = (char *) xmalloc (strlen (s1) + 1);
1568 register unsigned length;
1570 while (length-- > 0)
1575 mybcopy (in, out, length)
1576 register char *in, *out;
1577 register unsigned length;
1579 while (length-- > 0)
1594 tem = (char *) xmalloc (strlen (s1) + strlen (s2) + 2);
1603 xrealloc (ptr, size)
1607 char *result = (char *) realloc (ptr, size);
1609 fatal ("virtual memory exhausted");
1617 register char *val = (char *) malloc (size);
1620 fatal ("virtual memory exhausted");
1628 fprintf (stderr, "genrecog: ");
1629 fprintf (stderr, s, a1, a2);
1630 fprintf (stderr, "\n");
1631 fprintf (stderr, "after %d definitions\n", next_index);
1632 exit (FATAL_EXIT_CODE);
1635 /* More 'friendly' abort that prints the line and file.
1636 config.h can #define abort fancy_abort if you like that sort of thing. */
1641 fatal ("Internal gcc abort.");
1650 struct decision_head recog_tree;
1651 struct decision_head split_tree;
1653 extern rtx read_rtx ();
1656 obstack_init (rtl_obstack);
1657 recog_tree.first = recog_tree.last = split_tree.first = split_tree.last = 0;
1660 fatal ("No input file name.");
1662 infile = fopen (argv[1], "r");
1666 exit (FATAL_EXIT_CODE);
1673 printf ("/* Generated automatically by the program `genrecog'\n\
1674 from the machine description file `md'. */\n\n");
1676 printf ("#include \"config.h\"\n");
1677 printf ("#include \"rtl.h\"\n");
1678 printf ("#include \"insn-config.h\"\n");
1679 printf ("#include \"recog.h\"\n");
1680 printf ("#include \"real.h\"\n");
1681 printf ("#include \"output.h\"\n");
1682 printf ("#include \"flags.h\"\n");
1685 /* Read the machine description. */
1689 c = read_skip_spaces (infile);
1694 desc = read_rtx (infile);
1695 if (GET_CODE (desc) == DEFINE_INSN)
1696 recog_tree = merge_trees (recog_tree,
1697 make_insn_sequence (desc, RECOG));
1698 else if (GET_CODE (desc) == DEFINE_SPLIT)
1699 split_tree = merge_trees (split_tree,
1700 make_insn_sequence (desc, SPLIT));
1701 if (GET_CODE (desc) == DEFINE_PEEPHOLE
1702 || GET_CODE (desc) == DEFINE_EXPAND)
1708 /* `recog' contains a decision tree\n\
1709 that recognizes whether the rtx X0 is a valid instruction.\n\
1711 recog returns -1 if the rtx is not valid.\n\
1712 If the rtx is valid, recog returns a nonnegative number\n\
1713 which is the insn code number for the pattern that matched.\n");
1714 printf (" This is the same as the order in the machine description of\n\
1715 the entry that matched. This number can be used as an index into\n\
1716 entry that matched. This number can be used as an index into various\n\
1717 insn_* tables, such as insn_templates, insn_outfun, and insn_n_operands\n\
1718 (found in insn-output.c).\n\n");
1719 printf (" The third argument to recog is an optional pointer to an int.\n\
1720 If present, recog will accept a pattern if it matches except for\n\
1721 missing CLOBBER expressions at the end. In that case, the value\n\
1722 pointed to by the optional pointer will be set to the number of\n\
1723 CLOBBERs that need to be added (it should be initialized to zero by\n\
1724 the caller). If it is set nonzero, the caller should allocate a\n\
1725 PARALLEL of the appropriate size, copy the initial entries, and call\n\
1726 add_clobbers (found in insn-emit.c) to fill in the CLOBBERs.");
1728 if (split_tree.first)
1729 printf ("\n\n The function split_insns returns 0 if the rtl could not\n\
1730 be split or the split rtl in a SEQUENCE if it can be.");
1734 printf ("rtx recog_operand[MAX_RECOG_OPERANDS];\n\n");
1735 printf ("rtx *recog_operand_loc[MAX_RECOG_OPERANDS];\n\n");
1736 printf ("rtx *recog_dup_loc[MAX_DUP_OPERANDS];\n\n");
1737 printf ("char recog_dup_num[MAX_DUP_OPERANDS];\n\n");
1738 printf ("#define operands recog_operand\n\n");
1740 next_subroutine_number = 0;
1741 break_out_subroutines (recog_tree, RECOG, 1);
1742 write_subroutine (recog_tree.first, RECOG);
1744 next_subroutine_number = 0;
1745 break_out_subroutines (split_tree, SPLIT, 1);
1746 write_subroutine (split_tree.first, SPLIT);
1749 exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);