1 /* Generate code from machine description to recognize rtl as insns.
2 Copyright (C) 1987, 1988, 1992 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
60 extern rtx read_rtx ();
62 /* Data structure for a listhead of decision trees. The alternatives
63 to a node are kept in a doublely-linked list so we can easily add nodes
64 to the proper place when merging. */
66 struct decision_head { struct decision *first, *last; };
68 /* Data structure for decision tree for recognizing
69 legitimate instructions. */
73 int number; /* Node number, used for labels */
74 char *position; /* String denoting position in pattern */
75 RTX_CODE code; /* Code to test for or UNKNOWN to suppress */
76 char ignore_code; /* If non-zero, need not test code */
77 char ignore_mode; /* If non-zero, need not test mode */
78 int veclen; /* Length of vector, if nonzero */
79 enum machine_mode mode; /* Machine mode of node */
80 char enforce_mode; /* If non-zero, test `mode' */
81 char retest_code, retest_mode; /* See write_tree_1 */
82 int test_elt_zero_int; /* Nonzero if should test XINT (rtl, 0) */
83 int elt_zero_int; /* Required value for XINT (rtl, 0) */
84 int test_elt_one_int; /* Nonzero if should test XINT (rtl, 1) */
85 int elt_one_int; /* Required value for XINT (rtl, 1) */
86 int test_elt_zero_wide; /* Nonzero if should test XWINT (rtl, 0) */
87 HOST_WIDE_INT elt_zero_wide; /* Required value for XWINT (rtl, 0) */
88 char *tests; /* If nonzero predicate to call */
89 int pred; /* `preds' index of predicate or -1 */
90 char *c_test; /* Additional test to perform */
91 struct decision_head success; /* Nodes to test on success */
92 int insn_code_number; /* Insn number matched, if success */
93 int num_clobbers_to_add; /* Number of CLOBBERs to be added to pattern */
94 struct decision *next; /* Node to test on failure */
95 struct decision *prev; /* Node whose failure tests us */
96 struct decision *afterward; /* Node to test on success, but failure of
98 int opno; /* Operand number, if >= 0 */
99 int dupno; /* Number of operand to compare against */
100 int label_needed; /* Nonzero if label needed when writing tree */
101 int subroutine_number; /* Number of subroutine this node starts */
104 #define SUBROUTINE_THRESHOLD 50
106 static int next_subroutine_number;
108 /* We can write two types of subroutines: One for insn recognition and
109 one to split insns. This defines which type is being written. */
111 enum routine_type {RECOG, SPLIT};
113 /* Next available node number for tree nodes. */
115 static int next_number;
117 /* Next number to use as an insn_code. */
119 static int next_insn_code;
121 /* Similar, but counts all expressions in the MD file; used for
124 static int next_index;
126 /* Record the highest depth we ever have so we know how many variables to
127 allocate in each subroutine we make. */
129 static int max_depth;
131 /* This table contains a list of the rtl codes that can possibly match a
132 predicate defined in recog.c. The function `not_both_true' uses it to
133 deduce that there are no expressions that can be matches by certain pairs
134 of tree nodes. Also, if a predicate can match only one code, we can
135 hardwire that code into the node testing the predicate. */
137 static struct pred_table
140 RTX_CODE codes[NUM_RTX_CODE];
142 = {{"general_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
143 LABEL_REF, SUBREG, REG, MEM}},
144 #ifdef PREDICATE_CODES
147 {"address_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
148 LABEL_REF, SUBREG, REG, MEM, PLUS, MINUS, MULT}},
149 {"register_operand", {SUBREG, REG}},
150 {"scratch_operand", {SCRATCH, REG}},
151 {"immediate_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
153 {"const_int_operand", {CONST_INT}},
154 {"const_double_operand", {CONST_INT, CONST_DOUBLE}},
155 {"nonimmediate_operand", {SUBREG, REG, MEM}},
156 {"nonmemory_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
157 LABEL_REF, SUBREG, REG}},
158 {"push_operand", {MEM}},
159 {"memory_operand", {SUBREG, MEM}},
160 {"indirect_operand", {SUBREG, MEM}},
161 {"comparison_operation", {EQ, NE, LE, LT, GE, LT, LEU, LTU, GEU, GTU}},
162 {"mode_independent_operand", {CONST_INT, CONST_DOUBLE, CONST, SYMBOL_REF,
163 LABEL_REF, SUBREG, REG, MEM}}};
165 #define NUM_KNOWN_PREDS (sizeof preds / sizeof preds[0])
167 static int try_merge_1 ();
168 static int no_same_mode ();
169 static int same_codes ();
170 static int same_modes ();
172 static struct decision *add_to_sequence ();
173 static struct decision_head merge_trees ();
174 static struct decision *try_merge_2 ();
175 static void write_subroutine ();
176 static void print_code ();
177 static void clear_codes ();
178 static void clear_modes ();
179 static void change_state ();
180 static void write_tree ();
181 static char *copystr ();
182 static char *concat ();
183 static void fatal ();
185 static void mybzero ();
186 static void mybcopy ();
188 /* Construct and return a sequence of decisions
189 that will recognize INSN.
191 TYPE says what type of routine we are recognizing (RECOG or SPLIT). */
193 static struct decision_head
194 make_insn_sequence (insn, type)
196 enum routine_type type;
199 char *c_test = XSTR (insn, type == RECOG ? 2 : 1);
200 struct decision *last;
201 struct decision_head head;
203 if (XVECLEN (insn, type == RECOG) == 1)
204 x = XVECEXP (insn, type == RECOG, 0);
207 x = rtx_alloc (PARALLEL);
208 XVEC (x, 0) = XVEC (insn, type == RECOG);
209 PUT_MODE (x, VOIDmode);
212 last = add_to_sequence (x, &head, "");
215 last->c_test = c_test;
216 last->insn_code_number = next_insn_code;
217 last->num_clobbers_to_add = 0;
219 /* If this is not a DEFINE_SPLIT and X is a PARALLEL, see if it ends with a
220 group of CLOBBERs of (hard) registers or MATCH_SCRATCHes. If so, set up
221 to recognize the pattern without these CLOBBERs. */
223 if (type == RECOG && GET_CODE (x) == PARALLEL)
227 for (i = XVECLEN (x, 0); i > 0; i--)
228 if (GET_CODE (XVECEXP (x, 0, i - 1)) != CLOBBER
229 || (GET_CODE (XEXP (XVECEXP (x, 0, i - 1), 0)) != REG
230 && GET_CODE (XEXP (XVECEXP (x, 0, i - 1), 0)) != MATCH_SCRATCH))
233 if (i != XVECLEN (x, 0))
236 struct decision_head clobber_head;
239 new = XVECEXP (x, 0, 0);
244 new = rtx_alloc (PARALLEL);
245 XVEC (new, 0) = rtvec_alloc (i);
246 for (j = i - 1; j >= 0; j--)
247 XVECEXP (new, 0, j) = XVECEXP (x, 0, j);
250 last = add_to_sequence (new, &clobber_head, "");
253 last->c_test = c_test;
254 last->insn_code_number = next_insn_code;
255 last->num_clobbers_to_add = XVECLEN (x, 0) - i;
257 head = merge_trees (head, clobber_head);
264 /* Define the subroutine we will call below and emit in genemit. */
265 printf ("extern rtx gen_split_%d ();\n", last->insn_code_number);
270 /* Create a chain of nodes to verify that an rtl expression matches
273 LAST is a pointer to the listhead in the previous node in the chain (or
274 in the calling function, for the first node).
276 POSITION is the string representing the current position in the insn.
278 A pointer to the final node in the chain is returned. */
280 static struct decision *
281 add_to_sequence (pattern, last, position)
283 struct decision_head *last;
286 register RTX_CODE code;
287 register struct decision *new
288 = (struct decision *) xmalloc (sizeof (struct decision));
289 struct decision *this;
293 int depth = strlen (position);
296 if (depth > max_depth)
299 new->number = next_number++;
300 new->position = copystr (position);
301 new->ignore_code = 0;
302 new->ignore_mode = 0;
303 new->enforce_mode = 1;
304 new->retest_code = new->retest_mode = 0;
306 new->test_elt_zero_int = 0;
307 new->test_elt_one_int = 0;
308 new->test_elt_zero_wide = 0;
309 new->elt_zero_int = 0;
310 new->elt_one_int = 0;
311 new->elt_zero_wide = 0;
315 new->success.first = new->success.last = 0;
316 new->insn_code_number = -1;
317 new->num_clobbers_to_add = 0;
323 new->label_needed = 0;
324 new->subroutine_number = 0;
328 last->first = last->last = new;
330 newpos = (char *) alloca (depth + 2);
331 strcpy (newpos, position);
332 newpos[depth + 1] = 0;
336 new->mode = GET_MODE (pattern);
337 new->code = code = GET_CODE (pattern);
345 new->opno = XINT (pattern, 0);
346 new->code = (code == MATCH_PARALLEL ? PARALLEL : UNKNOWN);
347 new->enforce_mode = 0;
349 if (code == MATCH_SCRATCH)
350 new->tests = "scratch_operand";
352 new->tests = XSTR (pattern, 1);
354 if (*new->tests == 0)
357 /* See if we know about this predicate and save its number. If we do,
358 and it only accepts one code, note that fact. The predicate
359 `const_int_operand' only tests for a CONST_INT, so if we do so we
360 can avoid calling it at all.
362 Finally, if we know that the predicate does not allow CONST_INT, we
363 know that the only way the predicate can match is if the modes match
364 (here we use the kluge of relying on the fact that "address_operand"
365 accepts CONST_INT; otherwise, it would have to be a special case),
366 so we can test the mode (but we need not). This fact should
367 considerably simplify the generated code. */
370 for (i = 0; i < NUM_KNOWN_PREDS; i++)
371 if (! strcmp (preds[i].name, new->tests))
374 int allows_const_int = 0;
378 if (preds[i].codes[1] == 0 && new->code == UNKNOWN)
380 new->code = preds[i].codes[0];
381 if (! strcmp ("const_int_operand", new->tests))
382 new->tests = 0, new->pred = -1;
385 for (j = 0; j < NUM_RTX_CODE && preds[i].codes[j] != 0; j++)
386 if (preds[i].codes[j] == CONST_INT)
387 allows_const_int = 1;
389 if (! allows_const_int)
390 new->enforce_mode = new->ignore_mode= 1;
395 if (code == MATCH_OPERATOR || code == MATCH_PARALLEL)
397 for (i = 0; i < XVECLEN (pattern, 2); i++)
399 newpos[depth] = i + (code == MATCH_OPERATOR ? '0': 'a');
400 new = add_to_sequence (XVECEXP (pattern, 2, i),
401 &new->success, newpos);
408 new->opno = XINT (pattern, 0);
409 new->dupno = XINT (pattern, 0);
412 for (i = 0; i < XVECLEN (pattern, 1); i++)
414 newpos[depth] = i + '0';
415 new = add_to_sequence (XVECEXP (pattern, 1, i),
416 &new->success, newpos);
422 new->dupno = XINT (pattern, 0);
424 new->enforce_mode = 0;
428 pattern = XEXP (pattern, 0);
433 new = add_to_sequence (SET_DEST (pattern), &new->success, newpos);
434 this->success.first->enforce_mode = 1;
436 new = add_to_sequence (SET_SRC (pattern), &new->success, newpos);
438 /* If set are setting CC0 from anything other than a COMPARE, we
439 must enforce the mode so that we do not produce ambiguous insns. */
440 if (GET_CODE (SET_DEST (pattern)) == CC0
441 && GET_CODE (SET_SRC (pattern)) != COMPARE)
442 this->success.first->enforce_mode = 1;
447 case STRICT_LOW_PART:
449 new = add_to_sequence (XEXP (pattern, 0), &new->success, newpos);
450 this->success.first->enforce_mode = 1;
454 this->test_elt_one_int = 1;
455 this->elt_one_int = XINT (pattern, 1);
457 new = add_to_sequence (XEXP (pattern, 0), &new->success, newpos);
458 this->success.first->enforce_mode = 1;
464 new = add_to_sequence (XEXP (pattern, 0), &new->success, newpos);
465 this->success.first->enforce_mode = 1;
467 new = add_to_sequence (XEXP (pattern, 1), &new->success, newpos);
469 new = add_to_sequence (XEXP (pattern, 2), &new->success, newpos);
472 case EQ: case NE: case LE: case LT: case GE: case GT:
473 case LEU: case LTU: case GEU: case GTU:
474 /* If the first operand is (cc0), we don't have to do anything
476 if (GET_CODE (XEXP (pattern, 0)) == CC0)
479 /* ... fall through ... */
482 /* Enforce the mode on the first operand to avoid ambiguous insns. */
484 new = add_to_sequence (XEXP (pattern, 0), &new->success, newpos);
485 this->success.first->enforce_mode = 1;
487 new = add_to_sequence (XEXP (pattern, 1), &new->success, newpos);
491 fmt = GET_RTX_FORMAT (code);
492 len = GET_RTX_LENGTH (code);
493 for (i = 0; i < len; i++)
495 newpos[depth] = '0' + i;
496 if (fmt[i] == 'e' || fmt[i] == 'u')
497 new = add_to_sequence (XEXP (pattern, i), &new->success, newpos);
498 else if (fmt[i] == 'i' && i == 0)
500 this->test_elt_zero_int = 1;
501 this->elt_zero_int = XINT (pattern, i);
503 else if (fmt[i] == 'i' && i == 1)
505 this->test_elt_one_int = 1;
506 this->elt_one_int = XINT (pattern, i);
508 else if (fmt[i] == 'w' && i == 0)
510 this->test_elt_zero_wide = 1;
511 this->elt_zero_wide = XWINT (pattern, i);
513 else if (fmt[i] == 'E')
516 /* We do not handle a vector appearing as other than
517 the first item, just because nothing uses them
518 and by handling only the special case
519 we can use one element in newpos for either
520 the item number of a subexpression
521 or the element number in a vector. */
524 this->veclen = XVECLEN (pattern, i);
525 for (j = 0; j < XVECLEN (pattern, i); j++)
527 newpos[depth] = 'a' + j;
528 new = add_to_sequence (XVECEXP (pattern, i, j),
529 &new->success, newpos);
532 else if (fmt[i] != '0')
538 /* Return 1 if we can prove that there is no RTL that can match both
539 D1 and D2. Otherwise, return 0 (it may be that there is an RTL that
540 can match both or just that we couldn't prove there wasn't such an RTL).
542 TOPLEVEL is non-zero if we are to only look at the top level and not
543 recursively descend. */
546 not_both_true (d1, d2, toplevel)
547 struct decision *d1, *d2;
550 struct decision *p1, *p2;
552 /* If they are both to test modes and the modes are different, they aren't
553 both true. Similarly for codes, integer elements, and vector lengths. */
555 if ((d1->enforce_mode && d2->enforce_mode
556 && d1->mode != VOIDmode && d2->mode != VOIDmode && d1->mode != d2->mode)
557 || (d1->code != UNKNOWN && d2->code != UNKNOWN && d1->code != d2->code)
558 || (d1->test_elt_zero_int && d2->test_elt_zero_int
559 && d1->elt_zero_int != d2->elt_zero_int)
560 || (d1->test_elt_one_int && d2->test_elt_one_int
561 && d1->elt_one_int != d2->elt_one_int)
562 || (d1->test_elt_zero_wide && d2->test_elt_zero_wide
563 && d1->elt_zero_wide != d2->elt_zero_wide)
564 || (d1->veclen && d2->veclen && d1->veclen != d2->veclen))
567 /* If either is a wild-card MATCH_OPERAND without a predicate, it can match
568 absolutely anything, so we can't say that no intersection is possible.
569 This case is detected by having a zero TESTS field with a code of
572 if ((d1->tests == 0 && d1->code == UNKNOWN)
573 || (d2->tests == 0 && d2->code == UNKNOWN))
576 /* If either has a predicate that we know something about, set things up so
577 that D1 is the one that always has a known predicate. Then see if they
578 have any codes in common. */
580 if (d1->pred >= 0 || d2->pred >= 0)
585 p1 = d1, d1 = d2, d2 = p1;
587 /* If D2 tests an explicit code, see if it is in the list of valid codes
588 for D1's predicate. */
589 if (d2->code != UNKNOWN)
591 for (i = 0; i < NUM_RTX_CODE && preds[d1->pred].codes[i]; i++)
592 if (preds[d1->pred].codes[i] == d2->code)
595 if (preds[d1->pred].codes[i] == 0)
599 /* Otherwise see if the predicates have any codes in common. */
601 else if (d2->pred >= 0)
603 for (i = 0; i < NUM_RTX_CODE && preds[d1->pred].codes[i]; i++)
605 for (j = 0; j < NUM_RTX_CODE; j++)
606 if (preds[d2->pred].codes[j] == 0
607 || preds[d2->pred].codes[j] == preds[d1->pred].codes[i])
610 if (preds[d2->pred].codes[j] != 0)
614 if (preds[d1->pred].codes[i] == 0)
619 /* If we got here, we can't prove that D1 and D2 cannot both be true.
620 If we are only to check the top level, return 0. Otherwise, see if
621 we can prove that all choices in both successors are mutually
622 exclusive. If either does not have any successors, we can't prove
623 they can't both be true. */
625 if (toplevel || d1->success.first == 0 || d2->success.first == 0)
628 for (p1 = d1->success.first; p1; p1 = p1->next)
629 for (p2 = d2->success.first; p2; p2 = p2->next)
630 if (! not_both_true (p1, p2, 0))
636 /* Assuming that we can reorder all the alternatives at a specific point in
637 the tree (see discussion in merge_trees), we would prefer an ordering of
638 nodes where groups of consecutive nodes test the same mode and, within each
639 mode, groups of nodes test the same code. With this order, we can
640 construct nested switch statements, the inner one to test the code and
641 the outer one to test the mode.
643 We would like to list nodes testing for specific codes before those
644 that test predicates to avoid unnecessary function calls. Similarly,
645 tests for specific modes should precede nodes that allow any mode.
647 This function returns the merit (with 0 being the best) of inserting
648 a test involving the specified MODE and CODE after node P. If P is
649 zero, we are to determine the merit of inserting the test at the front
653 position_merit (p, mode, code)
655 enum machine_mode mode;
658 enum machine_mode p_mode;
660 /* The only time the front of the list is anything other than the worst
661 position is if we are testing a mode that isn't VOIDmode. */
663 return mode == VOIDmode ? 3 : 2;
665 p_mode = p->enforce_mode ? p->mode : VOIDmode;
667 /* The best case is if the codes and modes both match. */
668 if (p_mode == mode && p->code== code)
671 /* If the codes don't match, the next best case is if the modes match.
672 In that case, the best position for this node depends on whether
673 we are testing for a specific code or not. If we are, the best place
674 is after some other test for an explicit code and our mode or after
675 the last test in the previous mode if every test in our mode is for
678 If we are testing for UNKNOWN, then the next best case is at the end of
682 && ((p_mode == mode && p->code != UNKNOWN)
683 || (p_mode != mode && p->next
684 && (p->next->enforce_mode ? p->next->mode : VOIDmode) == mode
685 && (p->next->code == UNKNOWN))))
686 || (code == UNKNOWN && p_mode == mode
688 || (p->next->enforce_mode ? p->next->mode : VOIDmode) != mode)))
691 /* The third best case occurs when nothing is testing MODE. If MODE
692 is not VOIDmode, then the third best case is after something of any
693 mode that is not VOIDmode. If we are testing VOIDmode, the third best
694 place is the end of the list. */
697 && ((mode != VOIDmode && p_mode != VOIDmode)
698 || (mode == VOIDmode && p->next == 0)))
701 /* Otherwise, we have the worst case. */
705 /* Merge two decision tree listheads OLDH and ADDH,
706 modifying OLDH destructively, and return the merged tree. */
708 static struct decision_head
709 merge_trees (oldh, addh)
710 register struct decision_head oldh, addh;
712 struct decision *add, *next;
720 /* If we are adding things at different positions, something is wrong. */
721 if (strcmp (oldh.first->position, addh.first->position))
724 for (add = addh.first; add; add = next)
726 enum machine_mode add_mode = add->enforce_mode ? add->mode : VOIDmode;
727 struct decision *best_position = 0;
729 struct decision *old;
733 /* The semantics of pattern matching state that the tests are done in
734 the order given in the MD file so that if an insn matches two
735 patterns, the first one will be used. However, in practice, most,
736 if not all, patterns are unambiguous so that their order is
737 independent. In that case, we can merge identical tests and
738 group all similar modes and codes together.
740 Scan starting from the end of OLDH until we reach a point
741 where we reach the head of the list or where we pass a pattern
742 that could also be true if NEW is true. If we find an identical
743 pattern, we can merge them. Also, record the last node that tests
744 the same code and mode and the last one that tests just the same mode.
746 If we have no match, place NEW after the closest match we found. */
748 for (old = oldh.last; old; old = old->prev)
752 /* If we don't have anything to test except an additional test,
753 do not consider the two nodes equal. If we did, the test below
754 would cause an infinite recursion. */
755 if (old->tests == 0 && old->test_elt_zero_int == 0
756 && old->test_elt_one_int == 0 && old->veclen == 0
757 && old->test_elt_zero_wide == 0
758 && old->dupno == -1 && old->mode == VOIDmode
759 && old->code == UNKNOWN
760 && (old->c_test != 0 || add->c_test != 0))
763 else if ((old->tests == add->tests
764 || (old->pred >= 0 && old->pred == add->pred)
765 || (old->tests && add->tests
766 && !strcmp (old->tests, add->tests)))
767 && old->test_elt_zero_int == add->test_elt_zero_int
768 && old->elt_zero_int == add->elt_zero_int
769 && old->test_elt_one_int == add->test_elt_one_int
770 && old->elt_one_int == add->elt_one_int
771 && old->test_elt_zero_wide == add->test_elt_zero_wide
772 && old->elt_zero_wide == add->elt_zero_wide
773 && old->veclen == add->veclen
774 && old->dupno == add->dupno
775 && old->opno == add->opno
776 && old->code == add->code
777 && old->enforce_mode == add->enforce_mode
778 && old->mode == add->mode)
780 /* If the additional test is not the same, split both nodes
781 into nodes that just contain all things tested before the
782 additional test and nodes that contain the additional test
783 and actions when it is true. This optimization is important
784 because of the case where we have almost identical patterns
785 with different tests on target flags. */
787 if (old->c_test != add->c_test
788 && ! (old->c_test && add->c_test
789 && !strcmp (old->c_test, add->c_test)))
791 if (old->insn_code_number >= 0 || old->opno >= 0)
793 struct decision *split
794 = (struct decision *) xmalloc (sizeof (struct decision));
796 mybcopy (old, split, sizeof (struct decision));
798 old->success.first = old->success.last = split;
801 old->insn_code_number = -1;
802 old->num_clobbers_to_add = 0;
804 split->number = next_number++;
805 split->next = split->prev = 0;
806 split->mode = VOIDmode;
807 split->code = UNKNOWN;
809 split->test_elt_zero_int = 0;
810 split->test_elt_one_int = 0;
811 split->test_elt_zero_wide = 0;
816 if (add->insn_code_number >= 0 || add->opno >= 0)
818 struct decision *split
819 = (struct decision *) xmalloc (sizeof (struct decision));
821 mybcopy (add, split, sizeof (struct decision));
823 add->success.first = add->success.last = split;
826 add->insn_code_number = -1;
827 add->num_clobbers_to_add = 0;
829 split->number = next_number++;
830 split->next = split->prev = 0;
831 split->mode = VOIDmode;
832 split->code = UNKNOWN;
834 split->test_elt_zero_int = 0;
835 split->test_elt_one_int = 0;
836 split->test_elt_zero_wide = 0;
842 if (old->insn_code_number >= 0 && add->insn_code_number >= 0)
844 /* If one node is for a normal insn and the second is
845 for the base insn with clobbers stripped off, the
846 second node should be ignored. */
848 if (old->num_clobbers_to_add == 0
849 && add->num_clobbers_to_add > 0)
850 /* Nothing to do here. */
852 else if (old->num_clobbers_to_add > 0
853 && add->num_clobbers_to_add == 0)
855 /* In this case, replace OLD with ADD. */
856 old->insn_code_number = add->insn_code_number;
857 old->num_clobbers_to_add = 0;
860 fatal ("Two actions at one point in tree");
863 if (old->insn_code_number == -1)
864 old->insn_code_number = add->insn_code_number;
865 old->success = merge_trees (old->success, add->success);
870 /* Unless we have already found the best possible insert point,
871 see if this position is better. If so, record it. */
874 && ((our_merit = position_merit (old, add_mode, add->code))
876 best_merit = our_merit, best_position = old;
878 if (! not_both_true (old, add, 0))
882 /* If ADD was duplicate, we are done. */
886 /* Otherwise, find the best place to insert ADD. Normally this is
887 BEST_POSITION. However, if we went all the way to the top of
888 the list, it might be better to insert at the top. */
890 if (best_position == 0)
894 && position_merit (NULL_PTR, add_mode, add->code) < best_merit)
897 add->next = oldh.first;
898 oldh.first->prev = add;
904 add->prev = best_position;
905 add->next = best_position->next;
906 best_position->next = add;
907 if (best_position == oldh.last)
910 add->next->prev = add;
917 /* Count the number of subnodes of HEAD. If the number is high enough,
918 make the first node in HEAD start a separate subroutine in the C code
921 TYPE gives the type of routine we are writing.
923 INITIAL is non-zero if this is the highest-level node. We never write
927 break_out_subroutines (head, type, initial)
928 struct decision_head head;
929 enum routine_type type;
933 struct decision *node, *sub;
935 for (sub = head.first; sub; sub = sub->next)
936 size += 1 + break_out_subroutines (sub->success, type, 0);
938 if (size > SUBROUTINE_THRESHOLD && ! initial)
940 head.first->subroutine_number = ++next_subroutine_number;
941 write_subroutine (head.first, type);
947 /* Write out a subroutine of type TYPE to do comparisons starting at node
951 write_subroutine (tree, type)
952 struct decision *tree;
953 enum routine_type type;
958 printf ("rtx\nsplit");
960 printf ("int\nrecog");
962 if (tree != 0 && tree->subroutine_number > 0)
963 printf ("_%d", tree->subroutine_number);
964 else if (type == SPLIT)
967 printf (" (x0, insn");
969 printf (", pnum_clobbers");
972 printf (" register rtx x0;\n rtx insn;\n");
974 printf (" int *pnum_clobbers;\n");
977 printf (" register rtx *ro = &recog_operand[0];\n");
979 printf (" register rtx ");
980 for (i = 1; i < max_depth; i++)
983 printf ("x%d;\n", max_depth);
984 printf (" %s tem;\n", type == SPLIT ? "rtx" : "int");
985 write_tree (tree, "", NULL_PTR, 1, type);
986 printf (" ret0: return %d;\n}\n\n", type == SPLIT ? 0 : -1);
989 /* This table is used to indent the recog_* functions when we are inside
990 conditions or switch statements. We only support small indentations
991 and always indent at least two spaces. */
993 static char *indents[]
994 = {" ", " ", " ", " ", " ", " ", " ", " ",
995 "\t", "\t ", "\t ", "\t ", "\t ", "\t ", "\t ",
996 "\t\t", "\t\t ", "\t\t ", "\t\t ", "\t\t ", "\t\t "};
998 /* Write out C code to perform the decisions in TREE for a subroutine of
999 type TYPE. If all of the choices fail, branch to node AFTERWARD, if
1000 non-zero, otherwise return. PREVPOS is the position of the node that
1001 branched to this test.
1003 When we merged all alternatives, we tried to set up a convenient order.
1004 Specifically, tests involving the same mode are all grouped together,
1005 followed by a group that does not contain a mode test. Within each group
1006 of the same mode, we also group tests with the same code, followed by a
1007 group that does not test a code.
1009 Occasionally, we cannot arbitrarily reorder the tests so that multiple
1010 sequence of groups as described above are present.
1012 We generate two nested switch statements, the outer statement for
1013 testing modes, and the inner switch for testing RTX codes. It is
1014 not worth optimizing cases when only a small number of modes or
1015 codes is tested, since the compiler can do that when compiling the
1016 resulting function. We do check for when every test is the same mode
1020 write_tree_1 (tree, prevpos, afterward, type)
1021 struct decision *tree;
1023 struct decision *afterward;
1024 enum routine_type type;
1026 register struct decision *p, *p1;
1027 register int depth = tree ? strlen (tree->position) : 0;
1028 enum machine_mode switch_mode = VOIDmode;
1029 RTX_CODE switch_code = UNKNOWN;
1031 char modemap[NUM_MACHINE_MODES];
1032 char codemap[NUM_RTX_CODE];
1036 /* One tricky area is what is the exact state when we branch to a
1037 node's label. There are two cases where we branch: when looking at
1038 successors to a node, or when a set of tests fails.
1040 In the former case, we are always branching to the first node in a
1041 decision list and we want all required tests to be performed. We
1042 put the labels for such nodes in front of any switch or test statements.
1043 These branches are done without updating the position to that of the
1046 In the latter case, we are branching to a node that is not the first
1047 node in a decision list. We have already checked that it is possible
1048 for both the node we originally tested at this level and the node we
1049 are branching to to be both match some pattern. That means that they
1050 usually will be testing the same mode and code. So it is normally safe
1051 for such labels to be inside switch statements, since the tests done
1052 by virtue of arriving at that label will usually already have been
1053 done. The exception is a branch from a node that does not test a
1054 mode or code to one that does. In such cases, we set the `retest_mode'
1055 or `retest_code' flags. That will ensure that we start a new switch
1056 at that position and put the label before the switch.
1058 The branches in the latter case must set the position to that of the
1063 if (tree && tree->subroutine_number == 0)
1065 printf (" L%d:\n", tree->number);
1066 tree->label_needed = 0;
1071 change_state (prevpos, tree->position, 2);
1072 prevpos = tree->position;
1075 for (p = tree; p; p = p->next)
1077 enum machine_mode mode = p->enforce_mode ? p->mode : VOIDmode;
1079 int wrote_bracket = 0;
1082 if (p->success.first == 0 && p->insn_code_number < 0)
1085 /* Find the next alternative to p that might be true when p is true.
1086 Test that one next if p's successors fail. */
1088 for (p1 = p->next; p1 && not_both_true (p, p1, 1); p1 = p1->next)
1094 if (mode == VOIDmode && p1->enforce_mode && p1->mode != VOIDmode)
1095 p1->retest_mode = 1;
1096 if (p->code == UNKNOWN && p1->code != UNKNOWN)
1097 p1->retest_code = 1;
1098 p1->label_needed = 1;
1101 /* If we have a different code or mode than the last node and
1102 are in a switch on codes, we must either end the switch or
1103 go to another case. We must also end the switch if this
1104 node needs a label and to retest either the mode or code. */
1106 if (switch_code != UNKNOWN
1107 && (switch_code != p->code || switch_mode != mode
1108 || (p->label_needed && (p->retest_mode || p->retest_code))))
1110 enum rtx_code code = p->code;
1112 /* If P is testing a predicate that we know about and we haven't
1113 seen any of the codes that are valid for the predicate, we
1114 can write a series of "case" statement, one for each possible
1115 code. Since we are already in a switch, these redundant tests
1116 are very cheap and will reduce the number of predicate called. */
1120 for (i = 0; i < NUM_RTX_CODE && preds[p->pred].codes[i]; i++)
1121 if (codemap[(int) preds[p->pred].codes[i]])
1124 if (preds[p->pred].codes[i] == 0)
1125 code = MATCH_OPERAND;
1128 if (code == UNKNOWN || codemap[(int) code]
1129 || switch_mode != mode
1130 || (p->label_needed && (p->retest_mode || p->retest_code)))
1132 printf ("%s}\n", indents[indent - 2]);
1133 switch_code = UNKNOWN;
1139 printf ("%sbreak;\n", indents[indent]);
1141 if (code == MATCH_OPERAND)
1143 for (i = 0; i < NUM_RTX_CODE && preds[p->pred].codes[i]; i++)
1145 printf ("%scase ", indents[indent - 2]);
1146 print_code (preds[p->pred].codes[i]);
1148 codemap[(int) preds[p->pred].codes[i]] = 1;
1153 printf ("%scase ", indents[indent - 2]);
1156 codemap[(int) p->code] = 1;
1165 /* If we were previously in a switch on modes and now have a different
1166 mode, end at least the case, and maybe end the switch if we are
1167 not testing a mode or testing a mode whose case we already saw. */
1169 if (switch_mode != VOIDmode
1170 && (switch_mode != mode || (p->label_needed && p->retest_mode)))
1172 if (mode == VOIDmode || modemap[(int) mode]
1173 || (p->label_needed && p->retest_mode))
1175 printf ("%s}\n", indents[indent - 2]);
1176 switch_mode = VOIDmode;
1182 printf (" break;\n");
1183 printf (" case %smode:\n", GET_MODE_NAME (mode));
1185 modemap[(int) mode] = 1;
1191 /* If we are about to write dead code, something went wrong. */
1192 if (! p->label_needed && uncond)
1195 /* If we need a label and we will want to retest the mode or code at
1196 that label, write the label now. We have already ensured that
1197 things will be valid for the test. */
1199 if (p->label_needed && (p->retest_mode || p->retest_code))
1201 printf ("%sL%d:\n", indents[indent - 2], p->number);
1202 p->label_needed = 0;
1207 /* If we are not in any switches, see if we can shortcut things
1208 by checking for identical modes and codes. */
1210 if (switch_mode == VOIDmode && switch_code == UNKNOWN)
1212 /* If p and its alternatives all want the same mode,
1213 reject all others at once, first, then ignore the mode. */
1215 if (mode != VOIDmode && p->next && same_modes (p, mode))
1217 printf (" if (GET_MODE (x%d) != %smode)\n",
1218 depth, GET_MODE_NAME (p->mode));
1222 change_state (p->position, afterward->position, 6);
1223 printf (" goto L%d;\n }\n", afterward->number);
1226 printf (" goto ret0;\n");
1231 /* If p and its alternatives all want the same code,
1232 reject all others at once, first, then ignore the code. */
1234 if (p->code != UNKNOWN && p->next && same_codes (p, p->code))
1236 printf (" if (GET_CODE (x%d) != ", depth);
1237 print_code (p->code);
1242 change_state (p->position, afterward->position, indent + 4);
1243 printf (" goto L%d;\n }\n", afterward->number);
1246 printf (" goto ret0;\n");
1251 /* If we are not in a mode switch and we are testing for a specific
1252 mode, start a mode switch unless we have just one node or the next
1253 node is not testing a mode (we have already tested for the case of
1254 more than one mode, but all of the same mode). */
1256 if (switch_mode == VOIDmode && mode != VOIDmode && p->next != 0
1257 && p->next->enforce_mode && p->next->mode != VOIDmode)
1259 mybzero (modemap, sizeof modemap);
1260 printf ("%sswitch (GET_MODE (x%d))\n", indents[indent], depth);
1261 printf ("%s{\n", indents[indent + 2]);
1263 printf ("%scase %smode:\n", indents[indent - 2],
1264 GET_MODE_NAME (mode));
1265 modemap[(int) mode] = 1;
1269 /* Similarly for testing codes. */
1271 if (switch_code == UNKNOWN && p->code != UNKNOWN && ! p->ignore_code
1272 && p->next != 0 && p->next->code != UNKNOWN)
1274 mybzero (codemap, sizeof codemap);
1275 printf ("%sswitch (GET_CODE (x%d))\n", indents[indent], depth);
1276 printf ("%s{\n", indents[indent + 2]);
1278 printf ("%scase ", indents[indent - 2]);
1279 print_code (p->code);
1281 codemap[(int) p->code] = 1;
1282 switch_code = p->code;
1285 /* Now that most mode and code tests have been done, we can write out
1286 a label for an inner node, if we haven't already. */
1287 if (p->label_needed)
1288 printf ("%sL%d:\n", indents[indent - 2], p->number);
1290 inner_indent = indent;
1292 /* The only way we can have to do a mode or code test here is if
1293 this node needs such a test but is the only node to be tested.
1294 In that case, we won't have started a switch. Note that this is
1295 the only way the switch and test modes can disagree. */
1297 if ((mode != switch_mode && ! p->ignore_mode)
1298 || (p->code != switch_code && p->code != UNKNOWN && ! p->ignore_code)
1299 || p->test_elt_zero_int || p->test_elt_one_int
1300 || p->test_elt_zero_wide || p->veclen
1301 || p->dupno >= 0 || p->tests || p->num_clobbers_to_add)
1303 printf ("%sif (", indents[indent]);
1305 if (mode != switch_mode && ! p->ignore_mode)
1306 printf ("GET_MODE (x%d) == %smode && ",
1307 depth, GET_MODE_NAME (mode));
1308 if (p->code != switch_code && p->code != UNKNOWN && ! p->ignore_code)
1310 printf ("GET_CODE (x%d) == ", depth);
1311 print_code (p->code);
1315 if (p->test_elt_zero_int)
1316 printf ("XINT (x%d, 0) == %d && ", depth, p->elt_zero_int);
1317 if (p->test_elt_one_int)
1318 printf ("XINT (x%d, 1) == %d && ", depth, p->elt_one_int);
1319 if (p->test_elt_zero_wide)
1321 #if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_INT
1322 "XWINT (x%d, 0) == %d && ",
1324 "XWINT (x%d, 0) == %ld && ",
1326 depth, p->elt_zero_wide);
1328 printf ("XVECLEN (x%d, 0) == %d && ", depth, p->veclen);
1330 printf ("rtx_equal_p (x%d, ro[%d]) && ", depth, p->dupno);
1331 if (p->num_clobbers_to_add)
1332 printf ("pnum_clobbers != 0 && ");
1334 printf ("%s (x%d, %smode)", p->tests, depth,
1335 GET_MODE_NAME (p->mode));
1345 need_bracket = ! uncond;
1351 printf ("%s{\n", indents[inner_indent]);
1357 printf ("%sro[%d] = x%d;\n", indents[inner_indent], p->opno, depth);
1362 printf ("%sif (%s)\n", indents[inner_indent], p->c_test);
1368 if (p->insn_code_number >= 0)
1371 printf ("%sreturn gen_split_%d (operands);\n",
1372 indents[inner_indent], p->insn_code_number);
1375 if (p->num_clobbers_to_add)
1379 printf ("%s{\n", indents[inner_indent]);
1383 printf ("%s*pnum_clobbers = %d;\n",
1384 indents[inner_indent], p->num_clobbers_to_add);
1385 printf ("%sreturn %d;\n",
1386 indents[inner_indent], p->insn_code_number);
1391 printf ("%s}\n", indents[inner_indent]);
1395 printf ("%sreturn %d;\n",
1396 indents[inner_indent], p->insn_code_number);
1400 printf ("%sgoto L%d;\n", indents[inner_indent],
1401 p->success.first->number);
1404 printf ("%s}\n", indents[inner_indent - 2]);
1407 /* We have now tested all alternatives. End any switches we have open
1408 and branch to the alternative node unless we know that we can't fall
1409 through to the branch. */
1411 if (switch_code != UNKNOWN)
1413 printf ("%s}\n", indents[indent - 2]);
1418 if (switch_mode != VOIDmode)
1420 printf ("%s}\n", indents[indent - 2]);
1433 change_state (prevpos, afterward->position, 2);
1434 printf (" goto L%d;\n", afterward->number);
1437 printf (" goto ret0;\n");
1445 for (p1 = GET_RTX_NAME (code); *p1; p1++)
1447 if (*p1 >= 'a' && *p1 <= 'z')
1448 putchar (*p1 + 'A' - 'a');
1455 same_codes (p, code)
1456 register struct decision *p;
1457 register RTX_CODE code;
1459 for (; p; p = p->next)
1460 if (p->code != code)
1468 register struct decision *p;
1470 for (; p; p = p->next)
1475 same_modes (p, mode)
1476 register struct decision *p;
1477 register enum machine_mode mode;
1479 for (; p; p = p->next)
1480 if ((p->enforce_mode ? p->mode : VOIDmode) != mode)
1488 register struct decision *p;
1490 for (; p; p = p->next)
1491 p->enforce_mode = 0;
1494 /* Write out the decision tree starting at TREE for a subroutine of type TYPE.
1496 PREVPOS is the position at the node that branched to this node.
1498 INITIAL is nonzero if this is the first node we are writing in a subroutine.
1500 If all nodes are false, branch to the node AFTERWARD. */
1503 write_tree (tree, prevpos, afterward, initial, type)
1504 struct decision *tree;
1506 struct decision *afterward;
1508 enum routine_type type;
1510 register struct decision *p;
1511 char *name_prefix = (type == SPLIT ? "split" : "recog");
1512 char *call_suffix = (type == SPLIT ? "" : ", pnum_clobbers");
1514 if (! initial && tree->subroutine_number > 0)
1516 printf (" L%d:\n", tree->number);
1520 printf (" tem = %s_%d (x0, insn%s);\n",
1521 name_prefix, tree->subroutine_number, call_suffix);
1522 printf (" if (tem >= 0) return tem;\n");
1523 change_state (tree->position, afterward->position, 2);
1524 printf (" goto L%d;\n", afterward->number);
1527 printf (" return %s_%d (x0, insn%s);\n",
1528 name_prefix, tree->subroutine_number, call_suffix);
1532 write_tree_1 (tree, prevpos, afterward, type);
1534 for (p = tree; p; p = p->next)
1535 if (p->success.first)
1536 write_tree (p->success.first, p->position,
1537 p->afterward ? p->afterward : afterward, 0, type);
1541 /* Assuming that the state of argument is denoted by OLDPOS, take whatever
1542 actions are necessary to move to NEWPOS.
1544 INDENT says how many blanks to place at the front of lines. */
1547 change_state (oldpos, newpos, indent)
1552 int odepth = strlen (oldpos);
1554 int ndepth = strlen (newpos);
1556 /* Pop up as many levels as necessary. */
1558 while (strncmp (oldpos, newpos, depth))
1561 /* Go down to desired level. */
1563 while (depth < ndepth)
1565 if (newpos[depth] >= 'a' && newpos[depth] <= 'z')
1566 printf ("%sx%d = XVECEXP (x%d, 0, %d);\n",
1567 indents[indent], depth + 1, depth, newpos[depth] - 'a');
1569 printf ("%sx%d = XEXP (x%d, %c);\n",
1570 indents[indent], depth + 1, depth, newpos[depth]);
1584 tem = (char *) xmalloc (strlen (s1) + 1);
1593 register unsigned length;
1595 while (length-- > 0)
1600 mybcopy (in, out, length)
1601 register char *in, *out;
1602 register unsigned length;
1604 while (length-- > 0)
1619 tem = (char *) xmalloc (strlen (s1) + strlen (s2) + 2);
1628 xrealloc (ptr, size)
1632 char *result = (char *) realloc (ptr, size);
1634 fatal ("virtual memory exhausted");
1642 register char *val = (char *) malloc (size);
1645 fatal ("virtual memory exhausted");
1653 fprintf (stderr, "genrecog: ");
1654 fprintf (stderr, s, a1, a2);
1655 fprintf (stderr, "\n");
1656 fprintf (stderr, "after %d definitions\n", next_index);
1657 exit (FATAL_EXIT_CODE);
1660 /* More 'friendly' abort that prints the line and file.
1661 config.h can #define abort fancy_abort if you like that sort of thing. */
1666 fatal ("Internal gcc abort.");
1675 struct decision_head recog_tree;
1676 struct decision_head split_tree;
1680 obstack_init (rtl_obstack);
1681 recog_tree.first = recog_tree.last = split_tree.first = split_tree.last = 0;
1684 fatal ("No input file name.");
1686 infile = fopen (argv[1], "r");
1690 exit (FATAL_EXIT_CODE);
1697 printf ("/* Generated automatically by the program `genrecog'\n\
1698 from the machine description file `md'. */\n\n");
1700 printf ("#include \"config.h\"\n");
1701 printf ("#include \"rtl.h\"\n");
1702 printf ("#include \"insn-config.h\"\n");
1703 printf ("#include \"recog.h\"\n");
1704 printf ("#include \"real.h\"\n");
1705 printf ("#include \"output.h\"\n");
1706 printf ("#include \"flags.h\"\n");
1709 /* Read the machine description. */
1713 c = read_skip_spaces (infile);
1718 desc = read_rtx (infile);
1719 if (GET_CODE (desc) == DEFINE_INSN)
1720 recog_tree = merge_trees (recog_tree,
1721 make_insn_sequence (desc, RECOG));
1722 else if (GET_CODE (desc) == DEFINE_SPLIT)
1723 split_tree = merge_trees (split_tree,
1724 make_insn_sequence (desc, SPLIT));
1725 if (GET_CODE (desc) == DEFINE_PEEPHOLE
1726 || GET_CODE (desc) == DEFINE_EXPAND)
1732 /* `recog' contains a decision tree\n\
1733 that recognizes whether the rtx X0 is a valid instruction.\n\
1735 recog returns -1 if the rtx is not valid.\n\
1736 If the rtx is valid, recog returns a nonnegative number\n\
1737 which is the insn code number for the pattern that matched.\n");
1738 printf (" This is the same as the order in the machine description of\n\
1739 the entry that matched. This number can be used as an index into\n\
1740 entry that matched. This number can be used as an index into various\n\
1741 insn_* tables, such as insn_templates, insn_outfun, and insn_n_operands\n\
1742 (found in insn-output.c).\n\n");
1743 printf (" The third argument to recog is an optional pointer to an int.\n\
1744 If present, recog will accept a pattern if it matches except for\n\
1745 missing CLOBBER expressions at the end. In that case, the value\n\
1746 pointed to by the optional pointer will be set to the number of\n\
1747 CLOBBERs that need to be added (it should be initialized to zero by\n\
1748 the caller). If it is set nonzero, the caller should allocate a\n\
1749 PARALLEL of the appropriate size, copy the initial entries, and call\n\
1750 add_clobbers (found in insn-emit.c) to fill in the CLOBBERs.");
1752 if (split_tree.first)
1753 printf ("\n\n The function split_insns returns 0 if the rtl could not\n\
1754 be split or the split rtl in a SEQUENCE if it can be.");
1758 printf ("rtx recog_operand[MAX_RECOG_OPERANDS];\n\n");
1759 printf ("rtx *recog_operand_loc[MAX_RECOG_OPERANDS];\n\n");
1760 printf ("rtx *recog_dup_loc[MAX_DUP_OPERANDS];\n\n");
1761 printf ("char recog_dup_num[MAX_DUP_OPERANDS];\n\n");
1762 printf ("#define operands recog_operand\n\n");
1764 next_subroutine_number = 0;
1765 break_out_subroutines (recog_tree, RECOG, 1);
1766 write_subroutine (recog_tree.first, RECOG);
1768 next_subroutine_number = 0;
1769 break_out_subroutines (split_tree, SPLIT, 1);
1770 write_subroutine (split_tree.first, SPLIT);
1773 exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);