1 /* Common subexpression elimination for GNU compiler.
2 Copyright (C) 1987, 88, 89, 92, 93, 1994 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. */
22 /* Must precede rtl.h for FFS. */
27 #include "hard-reg-set.h"
30 #include "insn-config.h"
35 /* The basic idea of common subexpression elimination is to go
36 through the code, keeping a record of expressions that would
37 have the same value at the current scan point, and replacing
38 expressions encountered with the cheapest equivalent expression.
40 It is too complicated to keep track of the different possibilities
41 when control paths merge; so, at each label, we forget all that is
42 known and start fresh. This can be described as processing each
43 basic block separately. Note, however, that these are not quite
44 the same as the basic blocks found by a later pass and used for
45 data flow analysis and register packing. We do not need to start fresh
46 after a conditional jump instruction if there is no label there.
48 We use two data structures to record the equivalent expressions:
49 a hash table for most expressions, and several vectors together
50 with "quantity numbers" to record equivalent (pseudo) registers.
52 The use of the special data structure for registers is desirable
53 because it is faster. It is possible because registers references
54 contain a fairly small number, the register number, taken from
55 a contiguously allocated series, and two register references are
56 identical if they have the same number. General expressions
57 do not have any such thing, so the only way to retrieve the
58 information recorded on an expression other than a register
59 is to keep it in a hash table.
61 Registers and "quantity numbers":
63 At the start of each basic block, all of the (hardware and pseudo)
64 registers used in the function are given distinct quantity
65 numbers to indicate their contents. During scan, when the code
66 copies one register into another, we copy the quantity number.
67 When a register is loaded in any other way, we allocate a new
68 quantity number to describe the value generated by this operation.
69 `reg_qty' records what quantity a register is currently thought
72 All real quantity numbers are greater than or equal to `max_reg'.
73 If register N has not been assigned a quantity, reg_qty[N] will equal N.
75 Quantity numbers below `max_reg' do not exist and none of the `qty_...'
76 variables should be referenced with an index below `max_reg'.
78 We also maintain a bidirectional chain of registers for each
79 quantity number. `qty_first_reg', `qty_last_reg',
80 `reg_next_eqv' and `reg_prev_eqv' hold these chains.
82 The first register in a chain is the one whose lifespan is least local.
83 Among equals, it is the one that was seen first.
84 We replace any equivalent register with that one.
86 If two registers have the same quantity number, it must be true that
87 REG expressions with `qty_mode' must be in the hash table for both
88 registers and must be in the same class.
90 The converse is not true. Since hard registers may be referenced in
91 any mode, two REG expressions might be equivalent in the hash table
92 but not have the same quantity number if the quantity number of one
93 of the registers is not the same mode as those expressions.
95 Constants and quantity numbers
97 When a quantity has a known constant value, that value is stored
98 in the appropriate element of qty_const. This is in addition to
99 putting the constant in the hash table as is usual for non-regs.
101 Whether a reg or a constant is preferred is determined by the configuration
102 macro CONST_COSTS and will often depend on the constant value. In any
103 event, expressions containing constants can be simplified, by fold_rtx.
105 When a quantity has a known nearly constant value (such as an address
106 of a stack slot), that value is stored in the appropriate element
109 Integer constants don't have a machine mode. However, cse
110 determines the intended machine mode from the destination
111 of the instruction that moves the constant. The machine mode
112 is recorded in the hash table along with the actual RTL
113 constant expression so that different modes are kept separate.
117 To record known equivalences among expressions in general
118 we use a hash table called `table'. It has a fixed number of buckets
119 that contain chains of `struct table_elt' elements for expressions.
120 These chains connect the elements whose expressions have the same
123 Other chains through the same elements connect the elements which
124 currently have equivalent values.
126 Register references in an expression are canonicalized before hashing
127 the expression. This is done using `reg_qty' and `qty_first_reg'.
128 The hash code of a register reference is computed using the quantity
129 number, not the register number.
131 When the value of an expression changes, it is necessary to remove from the
132 hash table not just that expression but all expressions whose values
133 could be different as a result.
135 1. If the value changing is in memory, except in special cases
136 ANYTHING referring to memory could be changed. That is because
137 nobody knows where a pointer does not point.
138 The function `invalidate_memory' removes what is necessary.
140 The special cases are when the address is constant or is
141 a constant plus a fixed register such as the frame pointer
142 or a static chain pointer. When such addresses are stored in,
143 we can tell exactly which other such addresses must be invalidated
144 due to overlap. `invalidate' does this.
145 All expressions that refer to non-constant
146 memory addresses are also invalidated. `invalidate_memory' does this.
148 2. If the value changing is a register, all expressions
149 containing references to that register, and only those,
152 Because searching the entire hash table for expressions that contain
153 a register is very slow, we try to figure out when it isn't necessary.
154 Precisely, this is necessary only when expressions have been
155 entered in the hash table using this register, and then the value has
156 changed, and then another expression wants to be added to refer to
157 the register's new value. This sequence of circumstances is rare
158 within any one basic block.
160 The vectors `reg_tick' and `reg_in_table' are used to detect this case.
161 reg_tick[i] is incremented whenever a value is stored in register i.
162 reg_in_table[i] holds -1 if no references to register i have been
163 entered in the table; otherwise, it contains the value reg_tick[i] had
164 when the references were entered. If we want to enter a reference
165 and reg_in_table[i] != reg_tick[i], we must scan and remove old references.
166 Until we want to enter a new entry, the mere fact that the two vectors
167 don't match makes the entries be ignored if anyone tries to match them.
169 Registers themselves are entered in the hash table as well as in
170 the equivalent-register chains. However, the vectors `reg_tick'
171 and `reg_in_table' do not apply to expressions which are simple
172 register references. These expressions are removed from the table
173 immediately when they become invalid, and this can be done even if
174 we do not immediately search for all the expressions that refer to
177 A CLOBBER rtx in an instruction invalidates its operand for further
178 reuse. A CLOBBER or SET rtx whose operand is a MEM:BLK
179 invalidates everything that resides in memory.
183 Constant expressions that differ only by an additive integer
184 are called related. When a constant expression is put in
185 the table, the related expression with no constant term
186 is also entered. These are made to point at each other
187 so that it is possible to find out if there exists any
188 register equivalent to an expression related to a given expression. */
190 /* One plus largest register number used in this function. */
194 /* Length of vectors indexed by quantity number.
195 We know in advance we will not need a quantity number this big. */
199 /* Next quantity number to be allocated.
200 This is 1 + the largest number needed so far. */
204 /* Indexed by quantity number, gives the first (or last) (pseudo) register
205 in the chain of registers that currently contain this quantity. */
207 static int *qty_first_reg;
208 static int *qty_last_reg;
210 /* Index by quantity number, gives the mode of the quantity. */
212 static enum machine_mode *qty_mode;
214 /* Indexed by quantity number, gives the rtx of the constant value of the
215 quantity, or zero if it does not have a known value.
216 A sum of the frame pointer (or arg pointer) plus a constant
217 can also be entered here. */
219 static rtx *qty_const;
221 /* Indexed by qty number, gives the insn that stored the constant value
222 recorded in `qty_const'. */
224 static rtx *qty_const_insn;
226 /* The next three variables are used to track when a comparison between a
227 quantity and some constant or register has been passed. In that case, we
228 know the results of the comparison in case we see it again. These variables
229 record a comparison that is known to be true. */
231 /* Indexed by qty number, gives the rtx code of a comparison with a known
232 result involving this quantity. If none, it is UNKNOWN. */
233 static enum rtx_code *qty_comparison_code;
235 /* Indexed by qty number, gives the constant being compared against in a
236 comparison of known result. If no such comparison, it is undefined.
237 If the comparison is not with a constant, it is zero. */
239 static rtx *qty_comparison_const;
241 /* Indexed by qty number, gives the quantity being compared against in a
242 comparison of known result. If no such comparison, if it undefined.
243 If the comparison is not with a register, it is -1. */
245 static int *qty_comparison_qty;
248 /* For machines that have a CC0, we do not record its value in the hash
249 table since its use is guaranteed to be the insn immediately following
250 its definition and any other insn is presumed to invalidate it.
252 Instead, we store below the value last assigned to CC0. If it should
253 happen to be a constant, it is stored in preference to the actual
254 assigned value. In case it is a constant, we store the mode in which
255 the constant should be interpreted. */
257 static rtx prev_insn_cc0;
258 static enum machine_mode prev_insn_cc0_mode;
261 /* Previous actual insn. 0 if at first insn of basic block. */
263 static rtx prev_insn;
265 /* Insn being scanned. */
267 static rtx this_insn;
269 /* Index by (pseudo) register number, gives the quantity number
270 of the register's current contents. */
274 /* Index by (pseudo) register number, gives the number of the next (or
275 previous) (pseudo) register in the chain of registers sharing the same
278 Or -1 if this register is at the end of the chain.
280 If reg_qty[N] == N, reg_next_eqv[N] is undefined. */
282 static int *reg_next_eqv;
283 static int *reg_prev_eqv;
285 /* Index by (pseudo) register number, gives the number of times
286 that register has been altered in the current basic block. */
288 static int *reg_tick;
290 /* Index by (pseudo) register number, gives the reg_tick value at which
291 rtx's containing this register are valid in the hash table.
292 If this does not equal the current reg_tick value, such expressions
293 existing in the hash table are invalid.
294 If this is -1, no expressions containing this register have been
295 entered in the table. */
297 static int *reg_in_table;
299 /* A HARD_REG_SET containing all the hard registers for which there is
300 currently a REG expression in the hash table. Note the difference
301 from the above variables, which indicate if the REG is mentioned in some
302 expression in the table. */
304 static HARD_REG_SET hard_regs_in_table;
306 /* A HARD_REG_SET containing all the hard registers that are invalidated
309 static HARD_REG_SET regs_invalidated_by_call;
311 /* Two vectors of ints:
312 one containing max_reg -1's; the other max_reg + 500 (an approximation
313 for max_qty) elements where element i contains i.
314 These are used to initialize various other vectors fast. */
316 static int *all_minus_one;
317 static int *consec_ints;
319 /* CUID of insn that starts the basic block currently being cse-processed. */
321 static int cse_basic_block_start;
323 /* CUID of insn that ends the basic block currently being cse-processed. */
325 static int cse_basic_block_end;
327 /* Vector mapping INSN_UIDs to cuids.
328 The cuids are like uids but increase monotonically always.
329 We use them to see whether a reg is used outside a given basic block. */
331 static int *uid_cuid;
333 /* Highest UID in UID_CUID. */
336 /* Get the cuid of an insn. */
338 #define INSN_CUID(INSN) (uid_cuid[INSN_UID (INSN)])
340 /* Nonzero if cse has altered conditional jump insns
341 in such a way that jump optimization should be redone. */
343 static int cse_jumps_altered;
345 /* canon_hash stores 1 in do_not_record
346 if it notices a reference to CC0, PC, or some other volatile
349 static int do_not_record;
351 #ifdef LOAD_EXTEND_OP
353 /* Scratch rtl used when looking for load-extended copy of a MEM. */
354 static rtx memory_extend_rtx;
357 /* canon_hash stores 1 in hash_arg_in_memory
358 if it notices a reference to memory within the expression being hashed. */
360 static int hash_arg_in_memory;
362 /* canon_hash stores 1 in hash_arg_in_struct
363 if it notices a reference to memory that's part of a structure. */
365 static int hash_arg_in_struct;
367 /* The hash table contains buckets which are chains of `struct table_elt's,
368 each recording one expression's information.
369 That expression is in the `exp' field.
371 Those elements with the same hash code are chained in both directions
372 through the `next_same_hash' and `prev_same_hash' fields.
374 Each set of expressions with equivalent values
375 are on a two-way chain through the `next_same_value'
376 and `prev_same_value' fields, and all point with
377 the `first_same_value' field at the first element in
378 that chain. The chain is in order of increasing cost.
379 Each element's cost value is in its `cost' field.
381 The `in_memory' field is nonzero for elements that
382 involve any reference to memory. These elements are removed
383 whenever a write is done to an unidentified location in memory.
384 To be safe, we assume that a memory address is unidentified unless
385 the address is either a symbol constant or a constant plus
386 the frame pointer or argument pointer.
388 The `in_struct' field is nonzero for elements that
389 involve any reference to memory inside a structure or array.
391 The `related_value' field is used to connect related expressions
392 (that differ by adding an integer).
393 The related expressions are chained in a circular fashion.
394 `related_value' is zero for expressions for which this
397 The `cost' field stores the cost of this element's expression.
399 The `is_const' flag is set if the element is a constant (including
402 The `flag' field is used as a temporary during some search routines.
404 The `mode' field is usually the same as GET_MODE (`exp'), but
405 if `exp' is a CONST_INT and has no machine mode then the `mode'
406 field is the mode it was being used as. Each constant is
407 recorded separately for each mode it is used with. */
413 struct table_elt *next_same_hash;
414 struct table_elt *prev_same_hash;
415 struct table_elt *next_same_value;
416 struct table_elt *prev_same_value;
417 struct table_elt *first_same_value;
418 struct table_elt *related_value;
420 enum machine_mode mode;
427 /* We don't want a lot of buckets, because we rarely have very many
428 things stored in the hash table, and a lot of buckets slows
429 down a lot of loops that happen frequently. */
432 /* Compute hash code of X in mode M. Special-case case where X is a pseudo
433 register (hard registers may require `do_not_record' to be set). */
436 (GET_CODE (X) == REG && REGNO (X) >= FIRST_PSEUDO_REGISTER \
437 ? (((unsigned) REG << 7) + (unsigned) reg_qty[REGNO (X)]) % NBUCKETS \
438 : canon_hash (X, M) % NBUCKETS)
440 /* Determine whether register number N is considered a fixed register for CSE.
441 It is desirable to replace other regs with fixed regs, to reduce need for
443 A reg wins if it is either the frame pointer or designated as fixed,
444 but not if it is an overlapping register. */
445 #ifdef OVERLAPPING_REGNO_P
446 #define FIXED_REGNO_P(N) \
447 (((N) == FRAME_POINTER_REGNUM || (N) == HARD_FRAME_POINTER_REGNUM \
448 || fixed_regs[N] || global_regs[N]) \
449 && ! OVERLAPPING_REGNO_P ((N)))
451 #define FIXED_REGNO_P(N) \
452 ((N) == FRAME_POINTER_REGNUM || (N) == HARD_FRAME_POINTER_REGNUM \
453 || fixed_regs[N] || global_regs[N])
456 /* Compute cost of X, as stored in the `cost' field of a table_elt. Fixed
457 hard registers and pointers into the frame are the cheapest with a cost
458 of 0. Next come pseudos with a cost of one and other hard registers with
459 a cost of 2. Aside from these special cases, call `rtx_cost'. */
461 #define CHEAP_REGNO(N) \
462 ((N) == FRAME_POINTER_REGNUM || (N) == HARD_FRAME_POINTER_REGNUM \
463 || (N) == STACK_POINTER_REGNUM || (N) == ARG_POINTER_REGNUM \
464 || ((N) >= FIRST_VIRTUAL_REGISTER && (N) <= LAST_VIRTUAL_REGISTER) \
465 || ((N) < FIRST_PSEUDO_REGISTER \
466 && FIXED_REGNO_P (N) && REGNO_REG_CLASS (N) != NO_REGS))
468 /* A register is cheap if it is a user variable assigned to the register
469 or if its register number always corresponds to a cheap register. */
471 #define CHEAP_REG(N) \
472 ((REG_USERVAR_P (N) && REGNO (N) < FIRST_PSEUDO_REGISTER) \
473 || CHEAP_REGNO (REGNO (N)))
476 (GET_CODE (X) == REG \
477 ? (CHEAP_REG (X) ? 0 \
478 : REGNO (X) >= FIRST_PSEUDO_REGISTER ? 1 \
480 : rtx_cost (X, SET) * 2)
482 /* Determine if the quantity number for register X represents a valid index
483 into the `qty_...' variables. */
485 #define REGNO_QTY_VALID_P(N) (reg_qty[N] != (N))
487 static struct table_elt *table[NBUCKETS];
489 /* Chain of `struct table_elt's made so far for this function
490 but currently removed from the table. */
492 static struct table_elt *free_element_chain;
494 /* Number of `struct table_elt' structures made so far for this function. */
496 static int n_elements_made;
498 /* Maximum value `n_elements_made' has had so far in this compilation
499 for functions previously processed. */
501 static int max_elements_made;
503 /* Surviving equivalence class when two equivalence classes are merged
504 by recording the effects of a jump in the last insn. Zero if the
505 last insn was not a conditional jump. */
507 static struct table_elt *last_jump_equiv_class;
509 /* Set to the cost of a constant pool reference if one was found for a
510 symbolic constant. If this was found, it means we should try to
511 convert constants into constant pool entries if they don't fit in
514 static int constant_pool_entries_cost;
516 /* Bits describing what kind of values in memory must be invalidated
517 for a particular instruction. If all three bits are zero,
518 no memory refs need to be invalidated. Each bit is more powerful
519 than the preceding ones, and if a bit is set then the preceding
522 Here is how the bits are set:
523 Pushing onto the stack invalidates only the stack pointer,
524 writing at a fixed address invalidates only variable addresses,
525 writing in a structure element at variable address
526 invalidates all but scalar variables,
527 and writing in anything else at variable address invalidates everything. */
531 int sp : 1; /* Invalidate stack pointer. */
532 int var : 1; /* Invalidate variable addresses. */
533 int nonscalar : 1; /* Invalidate all but scalar variables. */
534 int all : 1; /* Invalidate all memory refs. */
537 /* Define maximum length of a branch path. */
539 #define PATHLENGTH 10
541 /* This data describes a block that will be processed by cse_basic_block. */
543 struct cse_basic_block_data {
544 /* Lowest CUID value of insns in block. */
546 /* Highest CUID value of insns in block. */
548 /* Total number of SETs in block. */
550 /* Last insn in the block. */
552 /* Size of current branch path, if any. */
554 /* Current branch path, indicating which branches will be taken. */
556 /* The branch insn. */
558 /* Whether it should be taken or not. AROUND is the same as taken
559 except that it is used when the destination label is not preceded
561 enum taken {TAKEN, NOT_TAKEN, AROUND} status;
565 /* Nonzero if X has the form (PLUS frame-pointer integer). We check for
566 virtual regs here because the simplify_*_operation routines are called
567 by integrate.c, which is called before virtual register instantiation. */
569 #define FIXED_BASE_PLUS_P(X) \
570 ((X) == frame_pointer_rtx || (X) == hard_frame_pointer_rtx \
571 || (X) == arg_pointer_rtx \
572 || (X) == virtual_stack_vars_rtx \
573 || (X) == virtual_incoming_args_rtx \
574 || (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == CONST_INT \
575 && (XEXP (X, 0) == frame_pointer_rtx \
576 || XEXP (X, 0) == hard_frame_pointer_rtx \
577 || XEXP (X, 0) == arg_pointer_rtx \
578 || XEXP (X, 0) == virtual_stack_vars_rtx \
579 || XEXP (X, 0) == virtual_incoming_args_rtx)))
581 /* Similar, but also allows reference to the stack pointer.
583 This used to include FIXED_BASE_PLUS_P, however, we can't assume that
584 arg_pointer_rtx by itself is nonzero, because on at least one machine,
585 the i960, the arg pointer is zero when it is unused. */
587 #define NONZERO_BASE_PLUS_P(X) \
588 ((X) == frame_pointer_rtx || (X) == hard_frame_pointer_rtx \
589 || (X) == virtual_stack_vars_rtx \
590 || (X) == virtual_incoming_args_rtx \
591 || (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == CONST_INT \
592 && (XEXP (X, 0) == frame_pointer_rtx \
593 || XEXP (X, 0) == hard_frame_pointer_rtx \
594 || XEXP (X, 0) == arg_pointer_rtx \
595 || XEXP (X, 0) == virtual_stack_vars_rtx \
596 || XEXP (X, 0) == virtual_incoming_args_rtx)) \
597 || (X) == stack_pointer_rtx \
598 || (X) == virtual_stack_dynamic_rtx \
599 || (X) == virtual_outgoing_args_rtx \
600 || (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == CONST_INT \
601 && (XEXP (X, 0) == stack_pointer_rtx \
602 || XEXP (X, 0) == virtual_stack_dynamic_rtx \
603 || XEXP (X, 0) == virtual_outgoing_args_rtx)))
605 static void new_basic_block PROTO((void));
606 static void make_new_qty PROTO((int));
607 static void make_regs_eqv PROTO((int, int));
608 static void delete_reg_equiv PROTO((int));
609 static int mention_regs PROTO((rtx));
610 static int insert_regs PROTO((rtx, struct table_elt *, int));
611 static void free_element PROTO((struct table_elt *));
612 static void remove_from_table PROTO((struct table_elt *, unsigned));
613 static struct table_elt *get_element PROTO((void));
614 static struct table_elt *lookup PROTO((rtx, unsigned, enum machine_mode)),
615 *lookup_for_remove PROTO((rtx, unsigned, enum machine_mode));
616 static rtx lookup_as_function PROTO((rtx, enum rtx_code));
617 static struct table_elt *insert PROTO((rtx, struct table_elt *, unsigned,
619 static void merge_equiv_classes PROTO((struct table_elt *,
620 struct table_elt *));
621 static void invalidate PROTO((rtx, enum machine_mode));
622 static void remove_invalid_refs PROTO((int));
623 static void rehash_using_reg PROTO((rtx));
624 static void invalidate_memory PROTO((struct write_data *));
625 static void invalidate_for_call PROTO((void));
626 static rtx use_related_value PROTO((rtx, struct table_elt *));
627 static unsigned canon_hash PROTO((rtx, enum machine_mode));
628 static unsigned safe_hash PROTO((rtx, enum machine_mode));
629 static int exp_equiv_p PROTO((rtx, rtx, int, int));
630 static void set_nonvarying_address_components PROTO((rtx, int, rtx *,
633 static int refers_to_p PROTO((rtx, rtx));
634 static int refers_to_mem_p PROTO((rtx, rtx, HOST_WIDE_INT,
636 static int cse_rtx_addr_varies_p PROTO((rtx));
637 static rtx canon_reg PROTO((rtx, rtx));
638 static void find_best_addr PROTO((rtx, rtx *));
639 static enum rtx_code find_comparison_args PROTO((enum rtx_code, rtx *, rtx *,
641 enum machine_mode *));
642 static rtx cse_gen_binary PROTO((enum rtx_code, enum machine_mode,
644 static rtx simplify_plus_minus PROTO((enum rtx_code, enum machine_mode,
646 static rtx fold_rtx PROTO((rtx, rtx));
647 static rtx equiv_constant PROTO((rtx));
648 static void record_jump_equiv PROTO((rtx, int));
649 static void record_jump_cond PROTO((enum rtx_code, enum machine_mode,
651 static void cse_insn PROTO((rtx, int));
652 static void note_mem_written PROTO((rtx, struct write_data *));
653 static void invalidate_from_clobbers PROTO((struct write_data *, rtx));
654 static rtx cse_process_notes PROTO((rtx, rtx));
655 static void cse_around_loop PROTO((rtx));
656 static void invalidate_skipped_set PROTO((rtx, rtx));
657 static void invalidate_skipped_block PROTO((rtx));
658 static void cse_check_loop_start PROTO((rtx, rtx));
659 static void cse_set_around_loop PROTO((rtx, rtx, rtx));
660 static rtx cse_basic_block PROTO((rtx, rtx, struct branch_path *, int));
661 static void count_reg_usage PROTO((rtx, int *, rtx, int));
663 extern int rtx_equal_function_value_matters;
665 /* Return an estimate of the cost of computing rtx X.
666 One use is in cse, to decide which expression to keep in the hash table.
667 Another is in rtl generation, to pick the cheapest way to multiply.
668 Other uses like the latter are expected in the future. */
670 /* Return the right cost to give to an operation
671 to make the cost of the corresponding register-to-register instruction
672 N times that of a fast register-to-register instruction. */
674 #define COSTS_N_INSNS(N) ((N) * 4 - 2)
677 rtx_cost (x, outer_code)
679 enum rtx_code outer_code;
682 register enum rtx_code code;
689 /* Compute the default costs of certain things.
690 Note that RTX_COSTS can override the defaults. */
696 /* Count multiplication by 2**n as a shift,
697 because if we are considering it, we would output it as a shift. */
698 if (GET_CODE (XEXP (x, 1)) == CONST_INT
699 && exact_log2 (INTVAL (XEXP (x, 1))) >= 0)
702 total = COSTS_N_INSNS (5);
708 total = COSTS_N_INSNS (7);
711 /* Used in loop.c and combine.c as a marker. */
715 /* We don't want these to be used in substitutions because
716 we have no way of validating the resulting insn. So assign
717 anything containing an ASM_OPERANDS a very high cost. */
727 return ! CHEAP_REG (x);
730 /* If we can't tie these modes, make this expensive. The larger
731 the mode, the more expensive it is. */
732 if (! MODES_TIEABLE_P (GET_MODE (x), GET_MODE (SUBREG_REG (x))))
733 return COSTS_N_INSNS (2
734 + GET_MODE_SIZE (GET_MODE (x)) / UNITS_PER_WORD);
737 RTX_COSTS (x, code, outer_code);
739 CONST_COSTS (x, code, outer_code);
742 /* Sum the costs of the sub-rtx's, plus cost of this operation,
743 which is already in total. */
745 fmt = GET_RTX_FORMAT (code);
746 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
748 total += rtx_cost (XEXP (x, i), code);
749 else if (fmt[i] == 'E')
750 for (j = 0; j < XVECLEN (x, i); j++)
751 total += rtx_cost (XVECEXP (x, i, j), code);
756 /* Clear the hash table and initialize each register with its own quantity,
757 for a new basic block. */
766 bzero ((char *) reg_tick, max_reg * sizeof (int));
768 bcopy ((char *) all_minus_one, (char *) reg_in_table,
769 max_reg * sizeof (int));
770 bcopy ((char *) consec_ints, (char *) reg_qty, max_reg * sizeof (int));
771 CLEAR_HARD_REG_SET (hard_regs_in_table);
773 /* The per-quantity values used to be initialized here, but it is
774 much faster to initialize each as it is made in `make_new_qty'. */
776 for (i = 0; i < NBUCKETS; i++)
778 register struct table_elt *this, *next;
779 for (this = table[i]; this; this = next)
781 next = this->next_same_hash;
786 bzero ((char *) table, sizeof table);
795 /* Say that register REG contains a quantity not in any register before
796 and initialize that quantity. */
804 if (next_qty >= max_qty)
807 q = reg_qty[reg] = next_qty++;
808 qty_first_reg[q] = reg;
809 qty_last_reg[q] = reg;
810 qty_const[q] = qty_const_insn[q] = 0;
811 qty_comparison_code[q] = UNKNOWN;
813 reg_next_eqv[reg] = reg_prev_eqv[reg] = -1;
816 /* Make reg NEW equivalent to reg OLD.
817 OLD is not changing; NEW is. */
820 make_regs_eqv (new, old)
821 register int new, old;
823 register int lastr, firstr;
824 register int q = reg_qty[old];
826 /* Nothing should become eqv until it has a "non-invalid" qty number. */
827 if (! REGNO_QTY_VALID_P (old))
831 firstr = qty_first_reg[q];
832 lastr = qty_last_reg[q];
834 /* Prefer fixed hard registers to anything. Prefer pseudo regs to other
835 hard regs. Among pseudos, if NEW will live longer than any other reg
836 of the same qty, and that is beyond the current basic block,
837 make it the new canonical replacement for this qty. */
838 if (! (firstr < FIRST_PSEUDO_REGISTER && FIXED_REGNO_P (firstr))
839 /* Certain fixed registers might be of the class NO_REGS. This means
840 that not only can they not be allocated by the compiler, but
841 they cannot be used in substitutions or canonicalizations
843 && (new >= FIRST_PSEUDO_REGISTER || REGNO_REG_CLASS (new) != NO_REGS)
844 && ((new < FIRST_PSEUDO_REGISTER && FIXED_REGNO_P (new))
845 || (new >= FIRST_PSEUDO_REGISTER
846 && (firstr < FIRST_PSEUDO_REGISTER
847 || ((uid_cuid[regno_last_uid[new]] > cse_basic_block_end
848 || (uid_cuid[regno_first_uid[new]]
849 < cse_basic_block_start))
850 && (uid_cuid[regno_last_uid[new]]
851 > uid_cuid[regno_last_uid[firstr]]))))))
853 reg_prev_eqv[firstr] = new;
854 reg_next_eqv[new] = firstr;
855 reg_prev_eqv[new] = -1;
856 qty_first_reg[q] = new;
860 /* If NEW is a hard reg (known to be non-fixed), insert at end.
861 Otherwise, insert before any non-fixed hard regs that are at the
862 end. Registers of class NO_REGS cannot be used as an
863 equivalent for anything. */
864 while (lastr < FIRST_PSEUDO_REGISTER && reg_prev_eqv[lastr] >= 0
865 && (REGNO_REG_CLASS (lastr) == NO_REGS || ! FIXED_REGNO_P (lastr))
866 && new >= FIRST_PSEUDO_REGISTER)
867 lastr = reg_prev_eqv[lastr];
868 reg_next_eqv[new] = reg_next_eqv[lastr];
869 if (reg_next_eqv[lastr] >= 0)
870 reg_prev_eqv[reg_next_eqv[lastr]] = new;
872 qty_last_reg[q] = new;
873 reg_next_eqv[lastr] = new;
874 reg_prev_eqv[new] = lastr;
878 /* Remove REG from its equivalence class. */
881 delete_reg_equiv (reg)
884 register int q = reg_qty[reg];
887 /* If invalid, do nothing. */
891 p = reg_prev_eqv[reg];
892 n = reg_next_eqv[reg];
901 qty_first_reg[q] = n;
906 /* Remove any invalid expressions from the hash table
907 that refer to any of the registers contained in expression X.
909 Make sure that newly inserted references to those registers
910 as subexpressions will be considered valid.
912 mention_regs is not called when a register itself
913 is being stored in the table.
915 Return 1 if we have done something that may have changed the hash code
922 register enum rtx_code code;
925 register int changed = 0;
933 register int regno = REGNO (x);
934 register int endregno
935 = regno + (regno >= FIRST_PSEUDO_REGISTER ? 1
936 : HARD_REGNO_NREGS (regno, GET_MODE (x)));
939 for (i = regno; i < endregno; i++)
941 if (reg_in_table[i] >= 0 && reg_in_table[i] != reg_tick[i])
942 remove_invalid_refs (i);
944 reg_in_table[i] = reg_tick[i];
950 /* If X is a comparison or a COMPARE and either operand is a register
951 that does not have a quantity, give it one. This is so that a later
952 call to record_jump_equiv won't cause X to be assigned a different
953 hash code and not found in the table after that call.
955 It is not necessary to do this here, since rehash_using_reg can
956 fix up the table later, but doing this here eliminates the need to
957 call that expensive function in the most common case where the only
958 use of the register is in the comparison. */
960 if (code == COMPARE || GET_RTX_CLASS (code) == '<')
962 if (GET_CODE (XEXP (x, 0)) == REG
963 && ! REGNO_QTY_VALID_P (REGNO (XEXP (x, 0))))
964 if (insert_regs (XEXP (x, 0), NULL_PTR, 0))
966 rehash_using_reg (XEXP (x, 0));
970 if (GET_CODE (XEXP (x, 1)) == REG
971 && ! REGNO_QTY_VALID_P (REGNO (XEXP (x, 1))))
972 if (insert_regs (XEXP (x, 1), NULL_PTR, 0))
974 rehash_using_reg (XEXP (x, 1));
979 fmt = GET_RTX_FORMAT (code);
980 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
982 changed |= mention_regs (XEXP (x, i));
983 else if (fmt[i] == 'E')
984 for (j = 0; j < XVECLEN (x, i); j++)
985 changed |= mention_regs (XVECEXP (x, i, j));
990 /* Update the register quantities for inserting X into the hash table
991 with a value equivalent to CLASSP.
992 (If the class does not contain a REG, it is irrelevant.)
993 If MODIFIED is nonzero, X is a destination; it is being modified.
994 Note that delete_reg_equiv should be called on a register
995 before insert_regs is done on that register with MODIFIED != 0.
997 Nonzero value means that elements of reg_qty have changed
998 so X's hash code may be different. */
1001 insert_regs (x, classp, modified)
1003 struct table_elt *classp;
1006 if (GET_CODE (x) == REG)
1008 register int regno = REGNO (x);
1010 /* If REGNO is in the equivalence table already but is of the
1011 wrong mode for that equivalence, don't do anything here. */
1013 if (REGNO_QTY_VALID_P (regno)
1014 && qty_mode[reg_qty[regno]] != GET_MODE (x))
1017 if (modified || ! REGNO_QTY_VALID_P (regno))
1020 for (classp = classp->first_same_value;
1022 classp = classp->next_same_value)
1023 if (GET_CODE (classp->exp) == REG
1024 && GET_MODE (classp->exp) == GET_MODE (x))
1026 make_regs_eqv (regno, REGNO (classp->exp));
1030 make_new_qty (regno);
1031 qty_mode[reg_qty[regno]] = GET_MODE (x);
1038 /* If X is a SUBREG, we will likely be inserting the inner register in the
1039 table. If that register doesn't have an assigned quantity number at
1040 this point but does later, the insertion that we will be doing now will
1041 not be accessible because its hash code will have changed. So assign
1042 a quantity number now. */
1044 else if (GET_CODE (x) == SUBREG && GET_CODE (SUBREG_REG (x)) == REG
1045 && ! REGNO_QTY_VALID_P (REGNO (SUBREG_REG (x))))
1047 insert_regs (SUBREG_REG (x), NULL_PTR, 0);
1048 mention_regs (SUBREG_REG (x));
1052 return mention_regs (x);
1055 /* Look in or update the hash table. */
1057 /* Put the element ELT on the list of free elements. */
1061 struct table_elt *elt;
1063 elt->next_same_hash = free_element_chain;
1064 free_element_chain = elt;
1067 /* Return an element that is free for use. */
1069 static struct table_elt *
1072 struct table_elt *elt = free_element_chain;
1075 free_element_chain = elt->next_same_hash;
1079 return (struct table_elt *) oballoc (sizeof (struct table_elt));
1082 /* Remove table element ELT from use in the table.
1083 HASH is its hash code, made using the HASH macro.
1084 It's an argument because often that is known in advance
1085 and we save much time not recomputing it. */
1088 remove_from_table (elt, hash)
1089 register struct table_elt *elt;
1095 /* Mark this element as removed. See cse_insn. */
1096 elt->first_same_value = 0;
1098 /* Remove the table element from its equivalence class. */
1101 register struct table_elt *prev = elt->prev_same_value;
1102 register struct table_elt *next = elt->next_same_value;
1104 if (next) next->prev_same_value = prev;
1107 prev->next_same_value = next;
1110 register struct table_elt *newfirst = next;
1113 next->first_same_value = newfirst;
1114 next = next->next_same_value;
1119 /* Remove the table element from its hash bucket. */
1122 register struct table_elt *prev = elt->prev_same_hash;
1123 register struct table_elt *next = elt->next_same_hash;
1125 if (next) next->prev_same_hash = prev;
1128 prev->next_same_hash = next;
1129 else if (table[hash] == elt)
1133 /* This entry is not in the proper hash bucket. This can happen
1134 when two classes were merged by `merge_equiv_classes'. Search
1135 for the hash bucket that it heads. This happens only very
1136 rarely, so the cost is acceptable. */
1137 for (hash = 0; hash < NBUCKETS; hash++)
1138 if (table[hash] == elt)
1143 /* Remove the table element from its related-value circular chain. */
1145 if (elt->related_value != 0 && elt->related_value != elt)
1147 register struct table_elt *p = elt->related_value;
1148 while (p->related_value != elt)
1149 p = p->related_value;
1150 p->related_value = elt->related_value;
1151 if (p->related_value == p)
1152 p->related_value = 0;
1158 /* Look up X in the hash table and return its table element,
1159 or 0 if X is not in the table.
1161 MODE is the machine-mode of X, or if X is an integer constant
1162 with VOIDmode then MODE is the mode with which X will be used.
1164 Here we are satisfied to find an expression whose tree structure
1167 static struct table_elt *
1168 lookup (x, hash, mode)
1171 enum machine_mode mode;
1173 register struct table_elt *p;
1175 for (p = table[hash]; p; p = p->next_same_hash)
1176 if (mode == p->mode && ((x == p->exp && GET_CODE (x) == REG)
1177 || exp_equiv_p (x, p->exp, GET_CODE (x) != REG, 0)))
1183 /* Like `lookup' but don't care whether the table element uses invalid regs.
1184 Also ignore discrepancies in the machine mode of a register. */
1186 static struct table_elt *
1187 lookup_for_remove (x, hash, mode)
1190 enum machine_mode mode;
1192 register struct table_elt *p;
1194 if (GET_CODE (x) == REG)
1196 int regno = REGNO (x);
1197 /* Don't check the machine mode when comparing registers;
1198 invalidating (REG:SI 0) also invalidates (REG:DF 0). */
1199 for (p = table[hash]; p; p = p->next_same_hash)
1200 if (GET_CODE (p->exp) == REG
1201 && REGNO (p->exp) == regno)
1206 for (p = table[hash]; p; p = p->next_same_hash)
1207 if (mode == p->mode && (x == p->exp || exp_equiv_p (x, p->exp, 0, 0)))
1214 /* Look for an expression equivalent to X and with code CODE.
1215 If one is found, return that expression. */
1218 lookup_as_function (x, code)
1222 register struct table_elt *p = lookup (x, safe_hash (x, VOIDmode) % NBUCKETS,
1227 for (p = p->first_same_value; p; p = p->next_same_value)
1229 if (GET_CODE (p->exp) == code
1230 /* Make sure this is a valid entry in the table. */
1231 && exp_equiv_p (p->exp, p->exp, 1, 0))
1238 /* Insert X in the hash table, assuming HASH is its hash code
1239 and CLASSP is an element of the class it should go in
1240 (or 0 if a new class should be made).
1241 It is inserted at the proper position to keep the class in
1242 the order cheapest first.
1244 MODE is the machine-mode of X, or if X is an integer constant
1245 with VOIDmode then MODE is the mode with which X will be used.
1247 For elements of equal cheapness, the most recent one
1248 goes in front, except that the first element in the list
1249 remains first unless a cheaper element is added. The order of
1250 pseudo-registers does not matter, as canon_reg will be called to
1251 find the cheapest when a register is retrieved from the table.
1253 The in_memory field in the hash table element is set to 0.
1254 The caller must set it nonzero if appropriate.
1256 You should call insert_regs (X, CLASSP, MODIFY) before calling here,
1257 and if insert_regs returns a nonzero value
1258 you must then recompute its hash code before calling here.
1260 If necessary, update table showing constant values of quantities. */
1262 #define CHEAPER(X,Y) ((X)->cost < (Y)->cost)
1264 static struct table_elt *
1265 insert (x, classp, hash, mode)
1267 register struct table_elt *classp;
1269 enum machine_mode mode;
1271 register struct table_elt *elt;
1273 /* If X is a register and we haven't made a quantity for it,
1274 something is wrong. */
1275 if (GET_CODE (x) == REG && ! REGNO_QTY_VALID_P (REGNO (x)))
1278 /* If X is a hard register, show it is being put in the table. */
1279 if (GET_CODE (x) == REG && REGNO (x) < FIRST_PSEUDO_REGISTER)
1281 int regno = REGNO (x);
1282 int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (x));
1285 for (i = regno; i < endregno; i++)
1286 SET_HARD_REG_BIT (hard_regs_in_table, i);
1290 /* Put an element for X into the right hash bucket. */
1292 elt = get_element ();
1294 elt->cost = COST (x);
1295 elt->next_same_value = 0;
1296 elt->prev_same_value = 0;
1297 elt->next_same_hash = table[hash];
1298 elt->prev_same_hash = 0;
1299 elt->related_value = 0;
1302 elt->is_const = (CONSTANT_P (x)
1303 /* GNU C++ takes advantage of this for `this'
1304 (and other const values). */
1305 || (RTX_UNCHANGING_P (x)
1306 && GET_CODE (x) == REG
1307 && REGNO (x) >= FIRST_PSEUDO_REGISTER)
1308 || FIXED_BASE_PLUS_P (x));
1311 table[hash]->prev_same_hash = elt;
1314 /* Put it into the proper value-class. */
1317 classp = classp->first_same_value;
1318 if (CHEAPER (elt, classp))
1319 /* Insert at the head of the class */
1321 register struct table_elt *p;
1322 elt->next_same_value = classp;
1323 classp->prev_same_value = elt;
1324 elt->first_same_value = elt;
1326 for (p = classp; p; p = p->next_same_value)
1327 p->first_same_value = elt;
1331 /* Insert not at head of the class. */
1332 /* Put it after the last element cheaper than X. */
1333 register struct table_elt *p, *next;
1334 for (p = classp; (next = p->next_same_value) && CHEAPER (next, elt);
1336 /* Put it after P and before NEXT. */
1337 elt->next_same_value = next;
1339 next->prev_same_value = elt;
1340 elt->prev_same_value = p;
1341 p->next_same_value = elt;
1342 elt->first_same_value = classp;
1346 elt->first_same_value = elt;
1348 /* If this is a constant being set equivalent to a register or a register
1349 being set equivalent to a constant, note the constant equivalence.
1351 If this is a constant, it cannot be equivalent to a different constant,
1352 and a constant is the only thing that can be cheaper than a register. So
1353 we know the register is the head of the class (before the constant was
1356 If this is a register that is not already known equivalent to a
1357 constant, we must check the entire class.
1359 If this is a register that is already known equivalent to an insn,
1360 update `qty_const_insn' to show that `this_insn' is the latest
1361 insn making that quantity equivalent to the constant. */
1363 if (elt->is_const && classp && GET_CODE (classp->exp) == REG)
1365 qty_const[reg_qty[REGNO (classp->exp)]]
1366 = gen_lowpart_if_possible (qty_mode[reg_qty[REGNO (classp->exp)]], x);
1367 qty_const_insn[reg_qty[REGNO (classp->exp)]] = this_insn;
1370 else if (GET_CODE (x) == REG && classp && ! qty_const[reg_qty[REGNO (x)]])
1372 register struct table_elt *p;
1374 for (p = classp; p != 0; p = p->next_same_value)
1378 qty_const[reg_qty[REGNO (x)]]
1379 = gen_lowpart_if_possible (GET_MODE (x), p->exp);
1380 qty_const_insn[reg_qty[REGNO (x)]] = this_insn;
1386 else if (GET_CODE (x) == REG && qty_const[reg_qty[REGNO (x)]]
1387 && GET_MODE (x) == qty_mode[reg_qty[REGNO (x)]])
1388 qty_const_insn[reg_qty[REGNO (x)]] = this_insn;
1390 /* If this is a constant with symbolic value,
1391 and it has a term with an explicit integer value,
1392 link it up with related expressions. */
1393 if (GET_CODE (x) == CONST)
1395 rtx subexp = get_related_value (x);
1397 struct table_elt *subelt, *subelt_prev;
1401 /* Get the integer-free subexpression in the hash table. */
1402 subhash = safe_hash (subexp, mode) % NBUCKETS;
1403 subelt = lookup (subexp, subhash, mode);
1405 subelt = insert (subexp, NULL_PTR, subhash, mode);
1406 /* Initialize SUBELT's circular chain if it has none. */
1407 if (subelt->related_value == 0)
1408 subelt->related_value = subelt;
1409 /* Find the element in the circular chain that precedes SUBELT. */
1410 subelt_prev = subelt;
1411 while (subelt_prev->related_value != subelt)
1412 subelt_prev = subelt_prev->related_value;
1413 /* Put new ELT into SUBELT's circular chain just before SUBELT.
1414 This way the element that follows SUBELT is the oldest one. */
1415 elt->related_value = subelt_prev->related_value;
1416 subelt_prev->related_value = elt;
1423 /* Given two equivalence classes, CLASS1 and CLASS2, put all the entries from
1424 CLASS2 into CLASS1. This is done when we have reached an insn which makes
1425 the two classes equivalent.
1427 CLASS1 will be the surviving class; CLASS2 should not be used after this
1430 Any invalid entries in CLASS2 will not be copied. */
1433 merge_equiv_classes (class1, class2)
1434 struct table_elt *class1, *class2;
1436 struct table_elt *elt, *next, *new;
1438 /* Ensure we start with the head of the classes. */
1439 class1 = class1->first_same_value;
1440 class2 = class2->first_same_value;
1442 /* If they were already equal, forget it. */
1443 if (class1 == class2)
1446 for (elt = class2; elt; elt = next)
1450 enum machine_mode mode = elt->mode;
1452 next = elt->next_same_value;
1454 /* Remove old entry, make a new one in CLASS1's class.
1455 Don't do this for invalid entries as we cannot find their
1456 hash code (it also isn't necessary). */
1457 if (GET_CODE (exp) == REG || exp_equiv_p (exp, exp, 1, 0))
1459 hash_arg_in_memory = 0;
1460 hash_arg_in_struct = 0;
1461 hash = HASH (exp, mode);
1463 if (GET_CODE (exp) == REG)
1464 delete_reg_equiv (REGNO (exp));
1466 remove_from_table (elt, hash);
1468 if (insert_regs (exp, class1, 0))
1470 rehash_using_reg (exp);
1471 hash = HASH (exp, mode);
1473 new = insert (exp, class1, hash, mode);
1474 new->in_memory = hash_arg_in_memory;
1475 new->in_struct = hash_arg_in_struct;
1480 /* Remove from the hash table, or mark as invalid,
1481 all expressions whose values could be altered by storing in X.
1482 X is a register, a subreg, or a memory reference with nonvarying address
1483 (because, when a memory reference with a varying address is stored in,
1484 all memory references are removed by invalidate_memory
1485 so specific invalidation is superfluous).
1486 FULL_MODE, if not VOIDmode, indicates that this much should be invalidated
1487 instead of just the amount indicated by the mode of X. This is only used
1488 for bitfield stores into memory.
1490 A nonvarying address may be just a register or just
1491 a symbol reference, or it may be either of those plus
1492 a numeric offset. */
1495 invalidate (x, full_mode)
1497 enum machine_mode full_mode;
1500 register struct table_elt *p;
1502 HOST_WIDE_INT start, end;
1504 /* If X is a register, dependencies on its contents
1505 are recorded through the qty number mechanism.
1506 Just change the qty number of the register,
1507 mark it as invalid for expressions that refer to it,
1508 and remove it itself. */
1510 if (GET_CODE (x) == REG)
1512 register int regno = REGNO (x);
1513 register unsigned hash = HASH (x, GET_MODE (x));
1515 /* Remove REGNO from any quantity list it might be on and indicate
1516 that it's value might have changed. If it is a pseudo, remove its
1517 entry from the hash table.
1519 For a hard register, we do the first two actions above for any
1520 additional hard registers corresponding to X. Then, if any of these
1521 registers are in the table, we must remove any REG entries that
1522 overlap these registers. */
1524 delete_reg_equiv (regno);
1527 if (regno >= FIRST_PSEUDO_REGISTER)
1528 remove_from_table (lookup_for_remove (x, hash, GET_MODE (x)), hash);
1531 HOST_WIDE_INT in_table
1532 = TEST_HARD_REG_BIT (hard_regs_in_table, regno);
1533 int endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (x));
1534 int tregno, tendregno;
1535 register struct table_elt *p, *next;
1537 CLEAR_HARD_REG_BIT (hard_regs_in_table, regno);
1539 for (i = regno + 1; i < endregno; i++)
1541 in_table |= TEST_HARD_REG_BIT (hard_regs_in_table, i);
1542 CLEAR_HARD_REG_BIT (hard_regs_in_table, i);
1543 delete_reg_equiv (i);
1548 for (hash = 0; hash < NBUCKETS; hash++)
1549 for (p = table[hash]; p; p = next)
1551 next = p->next_same_hash;
1553 if (GET_CODE (p->exp) != REG
1554 || REGNO (p->exp) >= FIRST_PSEUDO_REGISTER)
1557 tregno = REGNO (p->exp);
1559 = tregno + HARD_REGNO_NREGS (tregno, GET_MODE (p->exp));
1560 if (tendregno > regno && tregno < endregno)
1561 remove_from_table (p, hash);
1568 if (GET_CODE (x) == SUBREG)
1570 if (GET_CODE (SUBREG_REG (x)) != REG)
1572 invalidate (SUBREG_REG (x), VOIDmode);
1576 /* X is not a register; it must be a memory reference with
1577 a nonvarying address. Remove all hash table elements
1578 that refer to overlapping pieces of memory. */
1580 if (GET_CODE (x) != MEM)
1583 if (full_mode == VOIDmode)
1584 full_mode = GET_MODE (x);
1586 set_nonvarying_address_components (XEXP (x, 0), GET_MODE_SIZE (full_mode),
1587 &base, &start, &end);
1589 for (i = 0; i < NBUCKETS; i++)
1591 register struct table_elt *next;
1592 for (p = table[i]; p; p = next)
1594 next = p->next_same_hash;
1595 if (refers_to_mem_p (p->exp, base, start, end))
1596 remove_from_table (p, i);
1601 /* Remove all expressions that refer to register REGNO,
1602 since they are already invalid, and we are about to
1603 mark that register valid again and don't want the old
1604 expressions to reappear as valid. */
1607 remove_invalid_refs (regno)
1611 register struct table_elt *p, *next;
1613 for (i = 0; i < NBUCKETS; i++)
1614 for (p = table[i]; p; p = next)
1616 next = p->next_same_hash;
1617 if (GET_CODE (p->exp) != REG
1618 && refers_to_regno_p (regno, regno + 1, p->exp, NULL_PTR))
1619 remove_from_table (p, i);
1623 /* Recompute the hash codes of any valid entries in the hash table that
1624 reference X, if X is a register, or SUBREG_REG (X) if X is a SUBREG.
1626 This is called when we make a jump equivalence. */
1629 rehash_using_reg (x)
1633 struct table_elt *p, *next;
1636 if (GET_CODE (x) == SUBREG)
1639 /* If X is not a register or if the register is known not to be in any
1640 valid entries in the table, we have no work to do. */
1642 if (GET_CODE (x) != REG
1643 || reg_in_table[REGNO (x)] < 0
1644 || reg_in_table[REGNO (x)] != reg_tick[REGNO (x)])
1647 /* Scan all hash chains looking for valid entries that mention X.
1648 If we find one and it is in the wrong hash chain, move it. We can skip
1649 objects that are registers, since they are handled specially. */
1651 for (i = 0; i < NBUCKETS; i++)
1652 for (p = table[i]; p; p = next)
1654 next = p->next_same_hash;
1655 if (GET_CODE (p->exp) != REG && reg_mentioned_p (x, p->exp)
1656 && exp_equiv_p (p->exp, p->exp, 1, 0)
1657 && i != (hash = safe_hash (p->exp, p->mode) % NBUCKETS))
1659 if (p->next_same_hash)
1660 p->next_same_hash->prev_same_hash = p->prev_same_hash;
1662 if (p->prev_same_hash)
1663 p->prev_same_hash->next_same_hash = p->next_same_hash;
1665 table[i] = p->next_same_hash;
1667 p->next_same_hash = table[hash];
1668 p->prev_same_hash = 0;
1670 table[hash]->prev_same_hash = p;
1676 /* Remove from the hash table all expressions that reference memory,
1677 or some of them as specified by *WRITES. */
1680 invalidate_memory (writes)
1681 struct write_data *writes;
1684 register struct table_elt *p, *next;
1685 int all = writes->all;
1686 int nonscalar = writes->nonscalar;
1688 for (i = 0; i < NBUCKETS; i++)
1689 for (p = table[i]; p; p = next)
1691 next = p->next_same_hash;
1694 || (nonscalar && p->in_struct)
1695 || cse_rtx_addr_varies_p (p->exp)))
1696 remove_from_table (p, i);
1700 /* Remove from the hash table any expression that is a call-clobbered
1701 register. Also update their TICK values. */
1704 invalidate_for_call ()
1706 int regno, endregno;
1709 struct table_elt *p, *next;
1712 /* Go through all the hard registers. For each that is clobbered in
1713 a CALL_INSN, remove the register from quantity chains and update
1714 reg_tick if defined. Also see if any of these registers is currently
1717 for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
1718 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
1720 delete_reg_equiv (regno);
1721 if (reg_tick[regno] >= 0)
1724 in_table |= (TEST_HARD_REG_BIT (hard_regs_in_table, regno) != 0);
1727 /* In the case where we have no call-clobbered hard registers in the
1728 table, we are done. Otherwise, scan the table and remove any
1729 entry that overlaps a call-clobbered register. */
1732 for (hash = 0; hash < NBUCKETS; hash++)
1733 for (p = table[hash]; p; p = next)
1735 next = p->next_same_hash;
1737 if (GET_CODE (p->exp) != REG
1738 || REGNO (p->exp) >= FIRST_PSEUDO_REGISTER)
1741 regno = REGNO (p->exp);
1742 endregno = regno + HARD_REGNO_NREGS (regno, GET_MODE (p->exp));
1744 for (i = regno; i < endregno; i++)
1745 if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
1747 remove_from_table (p, hash);
1753 /* Given an expression X of type CONST,
1754 and ELT which is its table entry (or 0 if it
1755 is not in the hash table),
1756 return an alternate expression for X as a register plus integer.
1757 If none can be found, return 0. */
1760 use_related_value (x, elt)
1762 struct table_elt *elt;
1764 register struct table_elt *relt = 0;
1765 register struct table_elt *p, *q;
1766 HOST_WIDE_INT offset;
1768 /* First, is there anything related known?
1769 If we have a table element, we can tell from that.
1770 Otherwise, must look it up. */
1772 if (elt != 0 && elt->related_value != 0)
1774 else if (elt == 0 && GET_CODE (x) == CONST)
1776 rtx subexp = get_related_value (x);
1778 relt = lookup (subexp,
1779 safe_hash (subexp, GET_MODE (subexp)) % NBUCKETS,
1786 /* Search all related table entries for one that has an
1787 equivalent register. */
1792 /* This loop is strange in that it is executed in two different cases.
1793 The first is when X is already in the table. Then it is searching
1794 the RELATED_VALUE list of X's class (RELT). The second case is when
1795 X is not in the table. Then RELT points to a class for the related
1798 Ensure that, whatever case we are in, that we ignore classes that have
1799 the same value as X. */
1801 if (rtx_equal_p (x, p->exp))
1804 for (q = p->first_same_value; q; q = q->next_same_value)
1805 if (GET_CODE (q->exp) == REG)
1811 p = p->related_value;
1813 /* We went all the way around, so there is nothing to be found.
1814 Alternatively, perhaps RELT was in the table for some other reason
1815 and it has no related values recorded. */
1816 if (p == relt || p == 0)
1823 offset = (get_integer_term (x) - get_integer_term (p->exp));
1824 /* Note: OFFSET may be 0 if P->xexp and X are related by commutativity. */
1825 return plus_constant (q->exp, offset);
1828 /* Hash an rtx. We are careful to make sure the value is never negative.
1829 Equivalent registers hash identically.
1830 MODE is used in hashing for CONST_INTs only;
1831 otherwise the mode of X is used.
1833 Store 1 in do_not_record if any subexpression is volatile.
1835 Store 1 in hash_arg_in_memory if X contains a MEM rtx
1836 which does not have the RTX_UNCHANGING_P bit set.
1837 In this case, also store 1 in hash_arg_in_struct
1838 if there is a MEM rtx which has the MEM_IN_STRUCT_P bit set.
1840 Note that cse_insn knows that the hash code of a MEM expression
1841 is just (int) MEM plus the hash code of the address. */
1844 canon_hash (x, mode)
1846 enum machine_mode mode;
1849 register unsigned hash = 0;
1850 register enum rtx_code code;
1853 /* repeat is used to turn tail-recursion into iteration. */
1858 code = GET_CODE (x);
1863 register int regno = REGNO (x);
1865 /* On some machines, we can't record any non-fixed hard register,
1866 because extending its life will cause reload problems. We
1867 consider ap, fp, and sp to be fixed for this purpose.
1868 On all machines, we can't record any global registers. */
1870 if (regno < FIRST_PSEUDO_REGISTER
1871 && (global_regs[regno]
1872 #ifdef SMALL_REGISTER_CLASSES
1873 || (! fixed_regs[regno]
1874 && regno != FRAME_POINTER_REGNUM
1875 && regno != HARD_FRAME_POINTER_REGNUM
1876 && regno != ARG_POINTER_REGNUM
1877 && regno != STACK_POINTER_REGNUM)
1884 hash += ((unsigned) REG << 7) + (unsigned) reg_qty[regno];
1890 unsigned HOST_WIDE_INT tem = INTVAL (x);
1891 hash += ((unsigned) CONST_INT << 7) + (unsigned) mode + tem;
1896 /* This is like the general case, except that it only counts
1897 the integers representing the constant. */
1898 hash += (unsigned) code + (unsigned) GET_MODE (x);
1899 for (i = 2; i < GET_RTX_LENGTH (CONST_DOUBLE); i++)
1901 unsigned tem = XINT (x, i);
1906 /* Assume there is only one rtx object for any given label. */
1909 += ((unsigned) LABEL_REF << 7) + (unsigned HOST_WIDE_INT) XEXP (x, 0);
1914 += ((unsigned) SYMBOL_REF << 7) + (unsigned HOST_WIDE_INT) XSTR (x, 0);
1918 if (MEM_VOLATILE_P (x))
1923 if (! RTX_UNCHANGING_P (x))
1925 hash_arg_in_memory = 1;
1926 if (MEM_IN_STRUCT_P (x)) hash_arg_in_struct = 1;
1928 /* Now that we have already found this special case,
1929 might as well speed it up as much as possible. */
1930 hash += (unsigned) MEM;
1941 case UNSPEC_VOLATILE:
1946 if (MEM_VOLATILE_P (x))
1953 i = GET_RTX_LENGTH (code) - 1;
1954 hash += (unsigned) code + (unsigned) GET_MODE (x);
1955 fmt = GET_RTX_FORMAT (code);
1960 rtx tem = XEXP (x, i);
1962 /* If we are about to do the last recursive call
1963 needed at this level, change it into iteration.
1964 This function is called enough to be worth it. */
1970 hash += canon_hash (tem, 0);
1972 else if (fmt[i] == 'E')
1973 for (j = 0; j < XVECLEN (x, i); j++)
1974 hash += canon_hash (XVECEXP (x, i, j), 0);
1975 else if (fmt[i] == 's')
1977 register unsigned char *p = (unsigned char *) XSTR (x, i);
1982 else if (fmt[i] == 'i')
1984 register unsigned tem = XINT (x, i);
1993 /* Like canon_hash but with no side effects. */
1998 enum machine_mode mode;
2000 int save_do_not_record = do_not_record;
2001 int save_hash_arg_in_memory = hash_arg_in_memory;
2002 int save_hash_arg_in_struct = hash_arg_in_struct;
2003 unsigned hash = canon_hash (x, mode);
2004 hash_arg_in_memory = save_hash_arg_in_memory;
2005 hash_arg_in_struct = save_hash_arg_in_struct;
2006 do_not_record = save_do_not_record;
2010 /* Return 1 iff X and Y would canonicalize into the same thing,
2011 without actually constructing the canonicalization of either one.
2012 If VALIDATE is nonzero,
2013 we assume X is an expression being processed from the rtl
2014 and Y was found in the hash table. We check register refs
2015 in Y for being marked as valid.
2017 If EQUAL_VALUES is nonzero, we allow a register to match a constant value
2018 that is known to be in the register. Ordinarily, we don't allow them
2019 to match, because letting them match would cause unpredictable results
2020 in all the places that search a hash table chain for an equivalent
2021 for a given value. A possible equivalent that has different structure
2022 has its hash code computed from different data. Whether the hash code
2023 is the same as that of the the given value is pure luck. */
2026 exp_equiv_p (x, y, validate, equal_values)
2032 register enum rtx_code code;
2035 /* Note: it is incorrect to assume an expression is equivalent to itself
2036 if VALIDATE is nonzero. */
2037 if (x == y && !validate)
2039 if (x == 0 || y == 0)
2042 code = GET_CODE (x);
2043 if (code != GET_CODE (y))
2048 /* If X is a constant and Y is a register or vice versa, they may be
2049 equivalent. We only have to validate if Y is a register. */
2050 if (CONSTANT_P (x) && GET_CODE (y) == REG
2051 && REGNO_QTY_VALID_P (REGNO (y))
2052 && GET_MODE (y) == qty_mode[reg_qty[REGNO (y)]]
2053 && rtx_equal_p (x, qty_const[reg_qty[REGNO (y)]])
2054 && (! validate || reg_in_table[REGNO (y)] == reg_tick[REGNO (y)]))
2057 if (CONSTANT_P (y) && code == REG
2058 && REGNO_QTY_VALID_P (REGNO (x))
2059 && GET_MODE (x) == qty_mode[reg_qty[REGNO (x)]]
2060 && rtx_equal_p (y, qty_const[reg_qty[REGNO (x)]]))
2066 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
2067 if (GET_MODE (x) != GET_MODE (y))
2077 return INTVAL (x) == INTVAL (y);
2080 return XEXP (x, 0) == XEXP (y, 0);
2083 return XSTR (x, 0) == XSTR (y, 0);
2087 int regno = REGNO (y);
2089 = regno + (regno >= FIRST_PSEUDO_REGISTER ? 1
2090 : HARD_REGNO_NREGS (regno, GET_MODE (y)));
2093 /* If the quantities are not the same, the expressions are not
2094 equivalent. If there are and we are not to validate, they
2095 are equivalent. Otherwise, ensure all regs are up-to-date. */
2097 if (reg_qty[REGNO (x)] != reg_qty[regno])
2103 for (i = regno; i < endregno; i++)
2104 if (reg_in_table[i] != reg_tick[i])
2110 /* For commutative operations, check both orders. */
2118 return ((exp_equiv_p (XEXP (x, 0), XEXP (y, 0), validate, equal_values)
2119 && exp_equiv_p (XEXP (x, 1), XEXP (y, 1),
2120 validate, equal_values))
2121 || (exp_equiv_p (XEXP (x, 0), XEXP (y, 1),
2122 validate, equal_values)
2123 && exp_equiv_p (XEXP (x, 1), XEXP (y, 0),
2124 validate, equal_values)));
2127 /* Compare the elements. If any pair of corresponding elements
2128 fail to match, return 0 for the whole things. */
2130 fmt = GET_RTX_FORMAT (code);
2131 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2136 if (! exp_equiv_p (XEXP (x, i), XEXP (y, i), validate, equal_values))
2141 if (XVECLEN (x, i) != XVECLEN (y, i))
2143 for (j = 0; j < XVECLEN (x, i); j++)
2144 if (! exp_equiv_p (XVECEXP (x, i, j), XVECEXP (y, i, j),
2145 validate, equal_values))
2150 if (strcmp (XSTR (x, i), XSTR (y, i)))
2155 if (XINT (x, i) != XINT (y, i))
2160 if (XWINT (x, i) != XWINT (y, i))
2175 /* Return 1 iff any subexpression of X matches Y.
2176 Here we do not require that X or Y be valid (for registers referred to)
2177 for being in the hash table. */
2184 register enum rtx_code code;
2190 if (x == 0 || y == 0)
2193 code = GET_CODE (x);
2194 /* If X as a whole has the same code as Y, they may match.
2196 if (code == GET_CODE (y))
2198 if (exp_equiv_p (x, y, 0, 1))
2202 /* X does not match, so try its subexpressions. */
2204 fmt = GET_RTX_FORMAT (code);
2205 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2214 if (refers_to_p (XEXP (x, i), y))
2217 else if (fmt[i] == 'E')
2220 for (j = 0; j < XVECLEN (x, i); j++)
2221 if (refers_to_p (XVECEXP (x, i, j), y))
2228 /* Given ADDR and SIZE (a memory address, and the size of the memory reference),
2229 set PBASE, PSTART, and PEND which correspond to the base of the address,
2230 the starting offset, and ending offset respectively.
2232 ADDR is known to be a nonvarying address. */
2234 /* ??? Despite what the comments say, this function is in fact frequently
2235 passed varying addresses. This does not appear to cause any problems. */
2238 set_nonvarying_address_components (addr, size, pbase, pstart, pend)
2242 HOST_WIDE_INT *pstart, *pend;
2245 HOST_WIDE_INT start, end;
2251 /* Registers with nonvarying addresses usually have constant equivalents;
2252 but the frame pointer register is also possible. */
2253 if (GET_CODE (base) == REG
2255 && REGNO_QTY_VALID_P (REGNO (base))
2256 && qty_mode[reg_qty[REGNO (base)]] == GET_MODE (base)
2257 && qty_const[reg_qty[REGNO (base)]] != 0)
2258 base = qty_const[reg_qty[REGNO (base)]];
2259 else if (GET_CODE (base) == PLUS
2260 && GET_CODE (XEXP (base, 1)) == CONST_INT
2261 && GET_CODE (XEXP (base, 0)) == REG
2263 && REGNO_QTY_VALID_P (REGNO (XEXP (base, 0)))
2264 && (qty_mode[reg_qty[REGNO (XEXP (base, 0))]]
2265 == GET_MODE (XEXP (base, 0)))
2266 && qty_const[reg_qty[REGNO (XEXP (base, 0))]])
2268 start = INTVAL (XEXP (base, 1));
2269 base = qty_const[reg_qty[REGNO (XEXP (base, 0))]];
2272 /* Handle everything that we can find inside an address that has been
2273 viewed as constant. */
2277 /* If no part of this switch does a "continue", the code outside
2278 will exit this loop. */
2280 switch (GET_CODE (base))
2283 /* By definition, operand1 of a LO_SUM is the associated constant
2284 address. Use the associated constant address as the base
2286 base = XEXP (base, 1);
2290 /* Strip off CONST. */
2291 base = XEXP (base, 0);
2295 if (GET_CODE (XEXP (base, 1)) == CONST_INT)
2297 start += INTVAL (XEXP (base, 1));
2298 base = XEXP (base, 0);
2304 /* Handle the case of an AND which is the negative of a power of
2305 two. This is used to represent unaligned memory operations. */
2306 if (GET_CODE (XEXP (base, 1)) == CONST_INT
2307 && exact_log2 (- INTVAL (XEXP (base, 1))) > 0)
2309 set_nonvarying_address_components (XEXP (base, 0), size,
2310 pbase, pstart, pend);
2312 /* Assume the worst misalignment. START is affected, but not
2313 END, so compensate but adjusting SIZE. Don't lose any
2314 constant we already had. */
2316 size = *pend - *pstart - INTVAL (XEXP (base, 1)) - 1;
2317 start += *pstart - INTVAL (XEXP (base, 1)) - 1;
2326 if (GET_CODE (base) == CONST_INT)
2328 start += INTVAL (base);
2334 /* Set the return values. */
2340 /* Return 1 iff any subexpression of X refers to memory
2341 at an address of BASE plus some offset
2342 such that any of the bytes' offsets fall between START (inclusive)
2343 and END (exclusive).
2345 The value is undefined if X is a varying address (as determined by
2346 cse_rtx_addr_varies_p). This function is not used in such cases.
2348 When used in the cse pass, `qty_const' is nonzero, and it is used
2349 to treat an address that is a register with a known constant value
2350 as if it were that constant value.
2351 In the loop pass, `qty_const' is zero, so this is not done. */
2354 refers_to_mem_p (x, base, start, end)
2356 HOST_WIDE_INT start, end;
2358 register HOST_WIDE_INT i;
2359 register enum rtx_code code;
2366 code = GET_CODE (x);
2369 register rtx addr = XEXP (x, 0); /* Get the address. */
2371 HOST_WIDE_INT mystart, myend;
2373 set_nonvarying_address_components (addr, GET_MODE_SIZE (GET_MODE (x)),
2374 &mybase, &mystart, &myend);
2377 /* refers_to_mem_p is never called with varying addresses.
2378 If the base addresses are not equal, there is no chance
2379 of the memory addresses conflicting. */
2380 if (! rtx_equal_p (mybase, base))
2383 return myend > start && mystart < end;
2386 /* X does not match, so try its subexpressions. */
2388 fmt = GET_RTX_FORMAT (code);
2389 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2398 if (refers_to_mem_p (XEXP (x, i), base, start, end))
2401 else if (fmt[i] == 'E')
2404 for (j = 0; j < XVECLEN (x, i); j++)
2405 if (refers_to_mem_p (XVECEXP (x, i, j), base, start, end))
2412 /* Nonzero if X refers to memory at a varying address;
2413 except that a register which has at the moment a known constant value
2414 isn't considered variable. */
2417 cse_rtx_addr_varies_p (x)
2420 /* We need not check for X and the equivalence class being of the same
2421 mode because if X is equivalent to a constant in some mode, it
2422 doesn't vary in any mode. */
2424 if (GET_CODE (x) == MEM
2425 && GET_CODE (XEXP (x, 0)) == REG
2426 && REGNO_QTY_VALID_P (REGNO (XEXP (x, 0)))
2427 && GET_MODE (XEXP (x, 0)) == qty_mode[reg_qty[REGNO (XEXP (x, 0))]]
2428 && qty_const[reg_qty[REGNO (XEXP (x, 0))]] != 0)
2431 if (GET_CODE (x) == MEM
2432 && GET_CODE (XEXP (x, 0)) == PLUS
2433 && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
2434 && GET_CODE (XEXP (XEXP (x, 0), 0)) == REG
2435 && REGNO_QTY_VALID_P (REGNO (XEXP (XEXP (x, 0), 0)))
2436 && (GET_MODE (XEXP (XEXP (x, 0), 0))
2437 == qty_mode[reg_qty[REGNO (XEXP (XEXP (x, 0), 0))]])
2438 && qty_const[reg_qty[REGNO (XEXP (XEXP (x, 0), 0))]])
2441 return rtx_addr_varies_p (x);
2444 /* Canonicalize an expression:
2445 replace each register reference inside it
2446 with the "oldest" equivalent register.
2448 If INSN is non-zero and we are replacing a pseudo with a hard register
2449 or vice versa, validate_change is used to ensure that INSN remains valid
2450 after we make our substitution. The calls are made with IN_GROUP non-zero
2451 so apply_change_group must be called upon the outermost return from this
2452 function (unless INSN is zero). The result of apply_change_group can
2453 generally be discarded since the changes we are making are optional. */
2461 register enum rtx_code code;
2467 code = GET_CODE (x);
2485 /* Never replace a hard reg, because hard regs can appear
2486 in more than one machine mode, and we must preserve the mode
2487 of each occurrence. Also, some hard regs appear in
2488 MEMs that are shared and mustn't be altered. Don't try to
2489 replace any reg that maps to a reg of class NO_REGS. */
2490 if (REGNO (x) < FIRST_PSEUDO_REGISTER
2491 || ! REGNO_QTY_VALID_P (REGNO (x)))
2494 first = qty_first_reg[reg_qty[REGNO (x)]];
2495 return (first >= FIRST_PSEUDO_REGISTER ? regno_reg_rtx[first]
2496 : REGNO_REG_CLASS (first) == NO_REGS ? x
2497 : gen_rtx (REG, qty_mode[reg_qty[REGNO (x)]], first));
2501 fmt = GET_RTX_FORMAT (code);
2502 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2508 rtx new = canon_reg (XEXP (x, i), insn);
2510 /* If replacing pseudo with hard reg or vice versa, ensure the
2511 insn remains valid. Likewise if the insn has MATCH_DUPs. */
2512 if (insn != 0 && new != 0
2513 && GET_CODE (new) == REG && GET_CODE (XEXP (x, i)) == REG
2514 && (((REGNO (new) < FIRST_PSEUDO_REGISTER)
2515 != (REGNO (XEXP (x, i)) < FIRST_PSEUDO_REGISTER))
2516 || insn_n_dups[recog_memoized (insn)] > 0))
2517 validate_change (insn, &XEXP (x, i), new, 1);
2521 else if (fmt[i] == 'E')
2522 for (j = 0; j < XVECLEN (x, i); j++)
2523 XVECEXP (x, i, j) = canon_reg (XVECEXP (x, i, j), insn);
2529 /* LOC is a location with INSN that is an operand address (the contents of
2530 a MEM). Find the best equivalent address to use that is valid for this
2533 On most CISC machines, complicated address modes are costly, and rtx_cost
2534 is a good approximation for that cost. However, most RISC machines have
2535 only a few (usually only one) memory reference formats. If an address is
2536 valid at all, it is often just as cheap as any other address. Hence, for
2537 RISC machines, we use the configuration macro `ADDRESS_COST' to compare the
2538 costs of various addresses. For two addresses of equal cost, choose the one
2539 with the highest `rtx_cost' value as that has the potential of eliminating
2540 the most insns. For equal costs, we choose the first in the equivalence
2541 class. Note that we ignore the fact that pseudo registers are cheaper
2542 than hard registers here because we would also prefer the pseudo registers.
2546 find_best_addr (insn, loc)
2550 struct table_elt *elt, *p;
2553 int found_better = 1;
2554 int save_do_not_record = do_not_record;
2555 int save_hash_arg_in_memory = hash_arg_in_memory;
2556 int save_hash_arg_in_struct = hash_arg_in_struct;
2561 /* Do not try to replace constant addresses or addresses of local and
2562 argument slots. These MEM expressions are made only once and inserted
2563 in many instructions, as well as being used to control symbol table
2564 output. It is not safe to clobber them.
2566 There are some uncommon cases where the address is already in a register
2567 for some reason, but we cannot take advantage of that because we have
2568 no easy way to unshare the MEM. In addition, looking up all stack
2569 addresses is costly. */
2570 if ((GET_CODE (addr) == PLUS
2571 && GET_CODE (XEXP (addr, 0)) == REG
2572 && GET_CODE (XEXP (addr, 1)) == CONST_INT
2573 && (regno = REGNO (XEXP (addr, 0)),
2574 regno == FRAME_POINTER_REGNUM || regno == HARD_FRAME_POINTER_REGNUM
2575 || regno == ARG_POINTER_REGNUM))
2576 || (GET_CODE (addr) == REG
2577 && (regno = REGNO (addr), regno == FRAME_POINTER_REGNUM
2578 || regno == HARD_FRAME_POINTER_REGNUM
2579 || regno == ARG_POINTER_REGNUM))
2580 || CONSTANT_ADDRESS_P (addr))
2583 /* If this address is not simply a register, try to fold it. This will
2584 sometimes simplify the expression. Many simplifications
2585 will not be valid, but some, usually applying the associative rule, will
2586 be valid and produce better code. */
2587 if (GET_CODE (addr) != REG
2588 && validate_change (insn, loc, fold_rtx (addr, insn), 0))
2591 /* If this address is not in the hash table, we can't look for equivalences
2592 of the whole address. Also, ignore if volatile. */
2595 hash = HASH (addr, Pmode);
2596 addr_volatile = do_not_record;
2597 do_not_record = save_do_not_record;
2598 hash_arg_in_memory = save_hash_arg_in_memory;
2599 hash_arg_in_struct = save_hash_arg_in_struct;
2604 elt = lookup (addr, hash, Pmode);
2606 #ifndef ADDRESS_COST
2609 our_cost = elt->cost;
2611 /* Find the lowest cost below ours that works. */
2612 for (elt = elt->first_same_value; elt; elt = elt->next_same_value)
2613 if (elt->cost < our_cost
2614 && (GET_CODE (elt->exp) == REG
2615 || exp_equiv_p (elt->exp, elt->exp, 1, 0))
2616 && validate_change (insn, loc,
2617 canon_reg (copy_rtx (elt->exp), NULL_RTX), 0))
2624 /* We need to find the best (under the criteria documented above) entry
2625 in the class that is valid. We use the `flag' field to indicate
2626 choices that were invalid and iterate until we can't find a better
2627 one that hasn't already been tried. */
2629 for (p = elt->first_same_value; p; p = p->next_same_value)
2632 while (found_better)
2634 int best_addr_cost = ADDRESS_COST (*loc);
2635 int best_rtx_cost = (elt->cost + 1) >> 1;
2636 struct table_elt *best_elt = elt;
2639 for (p = elt->first_same_value; p; p = p->next_same_value)
2641 && (GET_CODE (p->exp) == REG
2642 || exp_equiv_p (p->exp, p->exp, 1, 0))
2643 && (ADDRESS_COST (p->exp) < best_addr_cost
2644 || (ADDRESS_COST (p->exp) == best_addr_cost
2645 && (p->cost + 1) >> 1 > best_rtx_cost)))
2648 best_addr_cost = ADDRESS_COST (p->exp);
2649 best_rtx_cost = (p->cost + 1) >> 1;
2655 if (validate_change (insn, loc,
2656 canon_reg (copy_rtx (best_elt->exp),
2665 /* If the address is a binary operation with the first operand a register
2666 and the second a constant, do the same as above, but looking for
2667 equivalences of the register. Then try to simplify before checking for
2668 the best address to use. This catches a few cases: First is when we
2669 have REG+const and the register is another REG+const. We can often merge
2670 the constants and eliminate one insn and one register. It may also be
2671 that a machine has a cheap REG+REG+const. Finally, this improves the
2672 code on the Alpha for unaligned byte stores. */
2674 if (flag_expensive_optimizations
2675 && (GET_RTX_CLASS (GET_CODE (*loc)) == '2'
2676 || GET_RTX_CLASS (GET_CODE (*loc)) == 'c')
2677 && GET_CODE (XEXP (*loc, 0)) == REG
2678 && GET_CODE (XEXP (*loc, 1)) == CONST_INT)
2680 rtx c = XEXP (*loc, 1);
2683 hash = HASH (XEXP (*loc, 0), Pmode);
2684 do_not_record = save_do_not_record;
2685 hash_arg_in_memory = save_hash_arg_in_memory;
2686 hash_arg_in_struct = save_hash_arg_in_struct;
2688 elt = lookup (XEXP (*loc, 0), hash, Pmode);
2692 /* We need to find the best (under the criteria documented above) entry
2693 in the class that is valid. We use the `flag' field to indicate
2694 choices that were invalid and iterate until we can't find a better
2695 one that hasn't already been tried. */
2697 for (p = elt->first_same_value; p; p = p->next_same_value)
2700 while (found_better)
2702 int best_addr_cost = ADDRESS_COST (*loc);
2703 int best_rtx_cost = (COST (*loc) + 1) >> 1;
2704 struct table_elt *best_elt = elt;
2705 rtx best_rtx = *loc;
2708 /* This is at worst case an O(n^2) algorithm, so limit our search
2709 to the first 32 elements on the list. This avoids trouble
2710 compiling code with very long basic blocks that can easily
2711 call cse_gen_binary so many times that we run out of memory. */
2714 for (p = elt->first_same_value, count = 0;
2716 p = p->next_same_value, count++)
2718 && (GET_CODE (p->exp) == REG
2719 || exp_equiv_p (p->exp, p->exp, 1, 0)))
2721 rtx new = cse_gen_binary (GET_CODE (*loc), Pmode, p->exp, c);
2723 if ((ADDRESS_COST (new) < best_addr_cost
2724 || (ADDRESS_COST (new) == best_addr_cost
2725 && (COST (new) + 1) >> 1 > best_rtx_cost)))
2728 best_addr_cost = ADDRESS_COST (new);
2729 best_rtx_cost = (COST (new) + 1) >> 1;
2737 if (validate_change (insn, loc,
2738 canon_reg (copy_rtx (best_rtx),
2749 /* Given an operation (CODE, *PARG1, *PARG2), where code is a comparison
2750 operation (EQ, NE, GT, etc.), follow it back through the hash table and
2751 what values are being compared.
2753 *PARG1 and *PARG2 are updated to contain the rtx representing the values
2754 actually being compared. For example, if *PARG1 was (cc0) and *PARG2
2755 was (const_int 0), *PARG1 and *PARG2 will be set to the objects that were
2756 compared to produce cc0.
2758 The return value is the comparison operator and is either the code of
2759 A or the code corresponding to the inverse of the comparison. */
2761 static enum rtx_code
2762 find_comparison_args (code, parg1, parg2, pmode1, pmode2)
2765 enum machine_mode *pmode1, *pmode2;
2769 arg1 = *parg1, arg2 = *parg2;
2771 /* If ARG2 is const0_rtx, see what ARG1 is equivalent to. */
2773 while (arg2 == CONST0_RTX (GET_MODE (arg1)))
2775 /* Set non-zero when we find something of interest. */
2777 int reverse_code = 0;
2778 struct table_elt *p = 0;
2780 /* If arg1 is a COMPARE, extract the comparison arguments from it.
2781 On machines with CC0, this is the only case that can occur, since
2782 fold_rtx will return the COMPARE or item being compared with zero
2785 if (GET_CODE (arg1) == COMPARE && arg2 == const0_rtx)
2788 /* If ARG1 is a comparison operator and CODE is testing for
2789 STORE_FLAG_VALUE, get the inner arguments. */
2791 else if (GET_RTX_CLASS (GET_CODE (arg1)) == '<')
2794 || (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_INT
2795 && code == LT && STORE_FLAG_VALUE == -1)
2796 #ifdef FLOAT_STORE_FLAG_VALUE
2797 || (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_FLOAT
2798 && FLOAT_STORE_FLAG_VALUE < 0)
2803 || (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_INT
2804 && code == GE && STORE_FLAG_VALUE == -1)
2805 #ifdef FLOAT_STORE_FLAG_VALUE
2806 || (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_FLOAT
2807 && FLOAT_STORE_FLAG_VALUE < 0)
2810 x = arg1, reverse_code = 1;
2813 /* ??? We could also check for
2815 (ne (and (eq (...) (const_int 1))) (const_int 0))
2817 and related forms, but let's wait until we see them occurring. */
2820 /* Look up ARG1 in the hash table and see if it has an equivalence
2821 that lets us see what is being compared. */
2822 p = lookup (arg1, safe_hash (arg1, GET_MODE (arg1)) % NBUCKETS,
2824 if (p) p = p->first_same_value;
2826 for (; p; p = p->next_same_value)
2828 enum machine_mode inner_mode = GET_MODE (p->exp);
2830 /* If the entry isn't valid, skip it. */
2831 if (! exp_equiv_p (p->exp, p->exp, 1, 0))
2834 if (GET_CODE (p->exp) == COMPARE
2835 /* Another possibility is that this machine has a compare insn
2836 that includes the comparison code. In that case, ARG1 would
2837 be equivalent to a comparison operation that would set ARG1 to
2838 either STORE_FLAG_VALUE or zero. If this is an NE operation,
2839 ORIG_CODE is the actual comparison being done; if it is an EQ,
2840 we must reverse ORIG_CODE. On machine with a negative value
2841 for STORE_FLAG_VALUE, also look at LT and GE operations. */
2844 && GET_MODE_CLASS (inner_mode) == MODE_INT
2845 && (GET_MODE_BITSIZE (inner_mode)
2846 <= HOST_BITS_PER_WIDE_INT)
2847 && (STORE_FLAG_VALUE
2848 & ((HOST_WIDE_INT) 1
2849 << (GET_MODE_BITSIZE (inner_mode) - 1))))
2850 #ifdef FLOAT_STORE_FLAG_VALUE
2852 && GET_MODE_CLASS (inner_mode) == MODE_FLOAT
2853 && FLOAT_STORE_FLAG_VALUE < 0)
2856 && GET_RTX_CLASS (GET_CODE (p->exp)) == '<'))
2861 else if ((code == EQ
2863 && GET_MODE_CLASS (inner_mode) == MODE_INT
2864 && (GET_MODE_BITSIZE (inner_mode)
2865 <= HOST_BITS_PER_WIDE_INT)
2866 && (STORE_FLAG_VALUE
2867 & ((HOST_WIDE_INT) 1
2868 << (GET_MODE_BITSIZE (inner_mode) - 1))))
2869 #ifdef FLOAT_STORE_FLAG_VALUE
2871 && GET_MODE_CLASS (inner_mode) == MODE_FLOAT
2872 && FLOAT_STORE_FLAG_VALUE < 0)
2875 && GET_RTX_CLASS (GET_CODE (p->exp)) == '<')
2882 /* If this is fp + constant, the equivalent is a better operand since
2883 it may let us predict the value of the comparison. */
2884 else if (NONZERO_BASE_PLUS_P (p->exp))
2891 /* If we didn't find a useful equivalence for ARG1, we are done.
2892 Otherwise, set up for the next iteration. */
2896 arg1 = XEXP (x, 0), arg2 = XEXP (x, 1);
2897 if (GET_RTX_CLASS (GET_CODE (x)) == '<')
2898 code = GET_CODE (x);
2901 code = reverse_condition (code);
2904 /* Return our results. Return the modes from before fold_rtx
2905 because fold_rtx might produce const_int, and then it's too late. */
2906 *pmode1 = GET_MODE (arg1), *pmode2 = GET_MODE (arg2);
2907 *parg1 = fold_rtx (arg1, 0), *parg2 = fold_rtx (arg2, 0);
2912 /* Try to simplify a unary operation CODE whose output mode is to be
2913 MODE with input operand OP whose mode was originally OP_MODE.
2914 Return zero if no simplification can be made. */
2917 simplify_unary_operation (code, mode, op, op_mode)
2919 enum machine_mode mode;
2921 enum machine_mode op_mode;
2923 register int width = GET_MODE_BITSIZE (mode);
2925 /* The order of these tests is critical so that, for example, we don't
2926 check the wrong mode (input vs. output) for a conversion operation,
2927 such as FIX. At some point, this should be simplified. */
2929 #if !defined(REAL_IS_NOT_DOUBLE) || defined(REAL_ARITHMETIC)
2931 if (code == FLOAT && GET_MODE (op) == VOIDmode
2932 && (GET_CODE (op) == CONST_DOUBLE || GET_CODE (op) == CONST_INT))
2934 HOST_WIDE_INT hv, lv;
2937 if (GET_CODE (op) == CONST_INT)
2938 lv = INTVAL (op), hv = INTVAL (op) < 0 ? -1 : 0;
2940 lv = CONST_DOUBLE_LOW (op), hv = CONST_DOUBLE_HIGH (op);
2942 #ifdef REAL_ARITHMETIC
2943 REAL_VALUE_FROM_INT (d, lv, hv);
2947 d = (double) (~ hv);
2948 d *= ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
2949 * (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
2950 d += (double) (unsigned HOST_WIDE_INT) (~ lv);
2956 d *= ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
2957 * (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
2958 d += (double) (unsigned HOST_WIDE_INT) lv;
2960 #endif /* REAL_ARITHMETIC */
2962 return CONST_DOUBLE_FROM_REAL_VALUE (d, mode);
2964 else if (code == UNSIGNED_FLOAT && GET_MODE (op) == VOIDmode
2965 && (GET_CODE (op) == CONST_DOUBLE || GET_CODE (op) == CONST_INT))
2967 HOST_WIDE_INT hv, lv;
2970 if (GET_CODE (op) == CONST_INT)
2971 lv = INTVAL (op), hv = INTVAL (op) < 0 ? -1 : 0;
2973 lv = CONST_DOUBLE_LOW (op), hv = CONST_DOUBLE_HIGH (op);
2975 if (GET_MODE_BITSIZE (op_mode) >= HOST_BITS_PER_WIDE_INT * 2)
2978 hv = 0, lv &= GET_MODE_MASK (op_mode);
2980 #ifdef REAL_ARITHMETIC
2981 REAL_VALUE_FROM_UNSIGNED_INT (d, lv, hv);
2984 d = (double) (unsigned HOST_WIDE_INT) hv;
2985 d *= ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
2986 * (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
2987 d += (double) (unsigned HOST_WIDE_INT) lv;
2988 #endif /* REAL_ARITHMETIC */
2990 return CONST_DOUBLE_FROM_REAL_VALUE (d, mode);
2994 if (GET_CODE (op) == CONST_INT
2995 && width <= HOST_BITS_PER_WIDE_INT && width > 0)
2997 register HOST_WIDE_INT arg0 = INTVAL (op);
2998 register HOST_WIDE_INT val;
3011 val = (arg0 >= 0 ? arg0 : - arg0);
3015 /* Don't use ffs here. Instead, get low order bit and then its
3016 number. If arg0 is zero, this will return 0, as desired. */
3017 arg0 &= GET_MODE_MASK (mode);
3018 val = exact_log2 (arg0 & (- arg0)) + 1;
3026 if (op_mode == VOIDmode)
3028 if (GET_MODE_BITSIZE (op_mode) == HOST_BITS_PER_WIDE_INT)
3030 /* If we were really extending the mode,
3031 we would have to distinguish between zero-extension
3032 and sign-extension. */
3033 if (width != GET_MODE_BITSIZE (op_mode))
3037 else if (GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT)
3038 val = arg0 & ~((HOST_WIDE_INT) (-1) << GET_MODE_BITSIZE (op_mode));
3044 if (op_mode == VOIDmode)
3046 if (GET_MODE_BITSIZE (op_mode) == HOST_BITS_PER_WIDE_INT)
3048 /* If we were really extending the mode,
3049 we would have to distinguish between zero-extension
3050 and sign-extension. */
3051 if (width != GET_MODE_BITSIZE (op_mode))
3055 else if (GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT)
3058 = arg0 & ~((HOST_WIDE_INT) (-1) << GET_MODE_BITSIZE (op_mode));
3060 & ((HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (op_mode) - 1)))
3061 val -= (HOST_WIDE_INT) 1 << GET_MODE_BITSIZE (op_mode);
3074 /* Clear the bits that don't belong in our mode,
3075 unless they and our sign bit are all one.
3076 So we get either a reasonable negative value or a reasonable
3077 unsigned value for this mode. */
3078 if (width < HOST_BITS_PER_WIDE_INT
3079 && ((val & ((HOST_WIDE_INT) (-1) << (width - 1)))
3080 != ((HOST_WIDE_INT) (-1) << (width - 1))))
3081 val &= (1 << width) - 1;
3083 return GEN_INT (val);
3086 /* We can do some operations on integer CONST_DOUBLEs. Also allow
3087 for a DImode operation on a CONST_INT. */
3088 else if (GET_MODE (op) == VOIDmode && width <= HOST_BITS_PER_INT * 2
3089 && (GET_CODE (op) == CONST_DOUBLE || GET_CODE (op) == CONST_INT))
3091 HOST_WIDE_INT l1, h1, lv, hv;
3093 if (GET_CODE (op) == CONST_DOUBLE)
3094 l1 = CONST_DOUBLE_LOW (op), h1 = CONST_DOUBLE_HIGH (op);
3096 l1 = INTVAL (op), h1 = l1 < 0 ? -1 : 0;
3106 neg_double (l1, h1, &lv, &hv);
3111 neg_double (l1, h1, &lv, &hv);
3119 lv = HOST_BITS_PER_WIDE_INT + exact_log2 (h1 & (-h1)) + 1;
3121 lv = exact_log2 (l1 & (-l1)) + 1;
3125 /* This is just a change-of-mode, so do nothing. */
3130 if (op_mode == VOIDmode
3131 || GET_MODE_BITSIZE (op_mode) > HOST_BITS_PER_WIDE_INT)
3135 lv = l1 & GET_MODE_MASK (op_mode);
3139 if (op_mode == VOIDmode
3140 || GET_MODE_BITSIZE (op_mode) > HOST_BITS_PER_WIDE_INT)
3144 lv = l1 & GET_MODE_MASK (op_mode);
3145 if (GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT
3146 && (lv & ((HOST_WIDE_INT) 1
3147 << (GET_MODE_BITSIZE (op_mode) - 1))) != 0)
3148 lv -= (HOST_WIDE_INT) 1 << GET_MODE_BITSIZE (op_mode);
3150 hv = (lv < 0) ? ~ (HOST_WIDE_INT) 0 : 0;
3161 return immed_double_const (lv, hv, mode);
3164 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3165 else if (GET_CODE (op) == CONST_DOUBLE
3166 && GET_MODE_CLASS (mode) == MODE_FLOAT)
3172 if (setjmp (handler))
3173 /* There used to be a warning here, but that is inadvisable.
3174 People may want to cause traps, and the natural way
3175 to do it should not get a warning. */
3178 set_float_handler (handler);
3180 REAL_VALUE_FROM_CONST_DOUBLE (d, op);
3185 d = REAL_VALUE_NEGATE (d);
3189 if (REAL_VALUE_NEGATIVE (d))
3190 d = REAL_VALUE_NEGATE (d);
3193 case FLOAT_TRUNCATE:
3194 d = real_value_truncate (mode, d);
3198 /* All this does is change the mode. */
3202 d = REAL_VALUE_RNDZINT (d);
3206 d = REAL_VALUE_UNSIGNED_RNDZINT (d);
3216 x = CONST_DOUBLE_FROM_REAL_VALUE (d, mode);
3217 set_float_handler (NULL_PTR);
3221 else if (GET_CODE (op) == CONST_DOUBLE
3222 && GET_MODE_CLASS (GET_MODE (op)) == MODE_FLOAT
3223 && GET_MODE_CLASS (mode) == MODE_INT
3224 && width <= HOST_BITS_PER_WIDE_INT && width > 0)
3230 if (setjmp (handler))
3233 set_float_handler (handler);
3235 REAL_VALUE_FROM_CONST_DOUBLE (d, op);
3240 val = REAL_VALUE_FIX (d);
3244 val = REAL_VALUE_UNSIGNED_FIX (d);
3251 set_float_handler (NULL_PTR);
3253 /* Clear the bits that don't belong in our mode,
3254 unless they and our sign bit are all one.
3255 So we get either a reasonable negative value or a reasonable
3256 unsigned value for this mode. */
3257 if (width < HOST_BITS_PER_WIDE_INT
3258 && ((val & ((HOST_WIDE_INT) (-1) << (width - 1)))
3259 != ((HOST_WIDE_INT) (-1) << (width - 1))))
3260 val &= ((HOST_WIDE_INT) 1 << width) - 1;
3262 return GEN_INT (val);
3265 /* This was formerly used only for non-IEEE float.
3266 eggert@twinsun.com says it is safe for IEEE also. */
3269 /* There are some simplifications we can do even if the operands
3275 /* (not (not X)) == X, similarly for NEG. */
3276 if (GET_CODE (op) == code)
3277 return XEXP (op, 0);
3281 /* (sign_extend (truncate (minus (label_ref L1) (label_ref L2))))
3282 becomes just the MINUS if its mode is MODE. This allows
3283 folding switch statements on machines using casesi (such as
3285 if (GET_CODE (op) == TRUNCATE
3286 && GET_MODE (XEXP (op, 0)) == mode
3287 && GET_CODE (XEXP (op, 0)) == MINUS
3288 && GET_CODE (XEXP (XEXP (op, 0), 0)) == LABEL_REF
3289 && GET_CODE (XEXP (XEXP (op, 0), 1)) == LABEL_REF)
3290 return XEXP (op, 0);
3298 /* Simplify a binary operation CODE with result mode MODE, operating on OP0
3299 and OP1. Return 0 if no simplification is possible.
3301 Don't use this for relational operations such as EQ or LT.
3302 Use simplify_relational_operation instead. */
3305 simplify_binary_operation (code, mode, op0, op1)
3307 enum machine_mode mode;
3310 register HOST_WIDE_INT arg0, arg1, arg0s, arg1s;
3312 int width = GET_MODE_BITSIZE (mode);
3315 /* Relational operations don't work here. We must know the mode
3316 of the operands in order to do the comparison correctly.
3317 Assuming a full word can give incorrect results.
3318 Consider comparing 128 with -128 in QImode. */
3320 if (GET_RTX_CLASS (code) == '<')
3323 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3324 if (GET_MODE_CLASS (mode) == MODE_FLOAT
3325 && GET_CODE (op0) == CONST_DOUBLE && GET_CODE (op1) == CONST_DOUBLE
3326 && mode == GET_MODE (op0) && mode == GET_MODE (op1))
3328 REAL_VALUE_TYPE f0, f1, value;
3331 if (setjmp (handler))
3334 set_float_handler (handler);
3336 REAL_VALUE_FROM_CONST_DOUBLE (f0, op0);
3337 REAL_VALUE_FROM_CONST_DOUBLE (f1, op1);
3338 f0 = real_value_truncate (mode, f0);
3339 f1 = real_value_truncate (mode, f1);
3341 #ifdef REAL_ARITHMETIC
3342 REAL_ARITHMETIC (value, rtx_to_tree_code (code), f0, f1);
3356 #ifndef REAL_INFINITY
3363 value = MIN (f0, f1);
3366 value = MAX (f0, f1);
3373 value = real_value_truncate (mode, value);
3374 set_float_handler (NULL_PTR);
3375 return CONST_DOUBLE_FROM_REAL_VALUE (value, mode);
3377 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3379 /* We can fold some multi-word operations. */
3380 if (GET_MODE_CLASS (mode) == MODE_INT
3381 && width == HOST_BITS_PER_WIDE_INT * 2
3382 && (GET_CODE (op0) == CONST_DOUBLE || GET_CODE (op0) == CONST_INT)
3383 && (GET_CODE (op1) == CONST_DOUBLE || GET_CODE (op1) == CONST_INT))
3385 HOST_WIDE_INT l1, l2, h1, h2, lv, hv;
3387 if (GET_CODE (op0) == CONST_DOUBLE)
3388 l1 = CONST_DOUBLE_LOW (op0), h1 = CONST_DOUBLE_HIGH (op0);
3390 l1 = INTVAL (op0), h1 = l1 < 0 ? -1 : 0;
3392 if (GET_CODE (op1) == CONST_DOUBLE)
3393 l2 = CONST_DOUBLE_LOW (op1), h2 = CONST_DOUBLE_HIGH (op1);
3395 l2 = INTVAL (op1), h2 = l2 < 0 ? -1 : 0;
3400 /* A - B == A + (-B). */
3401 neg_double (l2, h2, &lv, &hv);
3404 /* .. fall through ... */
3407 add_double (l1, h1, l2, h2, &lv, &hv);
3411 mul_double (l1, h1, l2, h2, &lv, &hv);
3414 case DIV: case MOD: case UDIV: case UMOD:
3415 /* We'd need to include tree.h to do this and it doesn't seem worth
3420 lv = l1 & l2, hv = h1 & h2;
3424 lv = l1 | l2, hv = h1 | h2;
3428 lv = l1 ^ l2, hv = h1 ^ h2;
3434 && ((unsigned HOST_WIDE_INT) l1
3435 < (unsigned HOST_WIDE_INT) l2)))
3444 && ((unsigned HOST_WIDE_INT) l1
3445 > (unsigned HOST_WIDE_INT) l2)))
3452 if ((unsigned HOST_WIDE_INT) h1 < (unsigned HOST_WIDE_INT) h2
3454 && ((unsigned HOST_WIDE_INT) l1
3455 < (unsigned HOST_WIDE_INT) l2)))
3462 if ((unsigned HOST_WIDE_INT) h1 > (unsigned HOST_WIDE_INT) h2
3464 && ((unsigned HOST_WIDE_INT) l1
3465 > (unsigned HOST_WIDE_INT) l2)))
3471 case LSHIFTRT: case ASHIFTRT:
3473 case ROTATE: case ROTATERT:
3474 #ifdef SHIFT_COUNT_TRUNCATED
3475 if (SHIFT_COUNT_TRUNCATED)
3476 l2 &= (GET_MODE_BITSIZE (mode) - 1), h2 = 0;
3479 if (h2 != 0 || l2 < 0 || l2 >= GET_MODE_BITSIZE (mode))
3482 if (code == LSHIFTRT || code == ASHIFTRT)
3483 rshift_double (l1, h1, l2, GET_MODE_BITSIZE (mode), &lv, &hv,
3485 else if (code == ASHIFT)
3486 lshift_double (l1, h1, l2, GET_MODE_BITSIZE (mode), &lv, &hv, 1);
3487 else if (code == ROTATE)
3488 lrotate_double (l1, h1, l2, GET_MODE_BITSIZE (mode), &lv, &hv);
3489 else /* code == ROTATERT */
3490 rrotate_double (l1, h1, l2, GET_MODE_BITSIZE (mode), &lv, &hv);
3497 return immed_double_const (lv, hv, mode);
3500 if (GET_CODE (op0) != CONST_INT || GET_CODE (op1) != CONST_INT
3501 || width > HOST_BITS_PER_WIDE_INT || width == 0)
3503 /* Even if we can't compute a constant result,
3504 there are some cases worth simplifying. */
3509 /* In IEEE floating point, x+0 is not the same as x. Similarly
3510 for the other optimizations below. */
3511 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
3512 && FLOAT_MODE_P (mode) && ! flag_fast_math)
3515 if (op1 == CONST0_RTX (mode))
3518 /* ((-a) + b) -> (b - a) and similarly for (a + (-b)) */
3519 if (GET_CODE (op0) == NEG)
3520 return cse_gen_binary (MINUS, mode, op1, XEXP (op0, 0));
3521 else if (GET_CODE (op1) == NEG)
3522 return cse_gen_binary (MINUS, mode, op0, XEXP (op1, 0));
3524 /* Handle both-operands-constant cases. We can only add
3525 CONST_INTs to constants since the sum of relocatable symbols
3526 can't be handled by most assemblers. Don't add CONST_INT
3527 to CONST_INT since overflow won't be computed properly if wider
3528 than HOST_BITS_PER_WIDE_INT. */
3530 if (CONSTANT_P (op0) && GET_MODE (op0) != VOIDmode
3531 && GET_CODE (op1) == CONST_INT)
3532 return plus_constant (op0, INTVAL (op1));
3533 else if (CONSTANT_P (op1) && GET_MODE (op1) != VOIDmode
3534 && GET_CODE (op0) == CONST_INT)
3535 return plus_constant (op1, INTVAL (op0));
3537 /* See if this is something like X * C - X or vice versa or
3538 if the multiplication is written as a shift. If so, we can
3539 distribute and make a new multiply, shift, or maybe just
3540 have X (if C is 2 in the example above). But don't make
3541 real multiply if we didn't have one before. */
3543 if (! FLOAT_MODE_P (mode))
3545 HOST_WIDE_INT coeff0 = 1, coeff1 = 1;
3546 rtx lhs = op0, rhs = op1;
3549 if (GET_CODE (lhs) == NEG)
3550 coeff0 = -1, lhs = XEXP (lhs, 0);
3551 else if (GET_CODE (lhs) == MULT
3552 && GET_CODE (XEXP (lhs, 1)) == CONST_INT)
3554 coeff0 = INTVAL (XEXP (lhs, 1)), lhs = XEXP (lhs, 0);
3557 else if (GET_CODE (lhs) == ASHIFT
3558 && GET_CODE (XEXP (lhs, 1)) == CONST_INT
3559 && INTVAL (XEXP (lhs, 1)) >= 0
3560 && INTVAL (XEXP (lhs, 1)) < HOST_BITS_PER_WIDE_INT)
3562 coeff0 = ((HOST_WIDE_INT) 1) << INTVAL (XEXP (lhs, 1));
3563 lhs = XEXP (lhs, 0);
3566 if (GET_CODE (rhs) == NEG)
3567 coeff1 = -1, rhs = XEXP (rhs, 0);
3568 else if (GET_CODE (rhs) == MULT
3569 && GET_CODE (XEXP (rhs, 1)) == CONST_INT)
3571 coeff1 = INTVAL (XEXP (rhs, 1)), rhs = XEXP (rhs, 0);
3574 else if (GET_CODE (rhs) == ASHIFT
3575 && GET_CODE (XEXP (rhs, 1)) == CONST_INT
3576 && INTVAL (XEXP (rhs, 1)) >= 0
3577 && INTVAL (XEXP (rhs, 1)) < HOST_BITS_PER_WIDE_INT)
3579 coeff1 = ((HOST_WIDE_INT) 1) << INTVAL (XEXP (rhs, 1));
3580 rhs = XEXP (rhs, 0);
3583 if (rtx_equal_p (lhs, rhs))
3585 tem = cse_gen_binary (MULT, mode, lhs,
3586 GEN_INT (coeff0 + coeff1));
3587 return (GET_CODE (tem) == MULT && ! had_mult) ? 0 : tem;
3591 /* If one of the operands is a PLUS or a MINUS, see if we can
3592 simplify this by the associative law.
3593 Don't use the associative law for floating point.
3594 The inaccuracy makes it nonassociative,
3595 and subtle programs can break if operations are associated. */
3597 if (INTEGRAL_MODE_P (mode)
3598 && (GET_CODE (op0) == PLUS || GET_CODE (op0) == MINUS
3599 || GET_CODE (op1) == PLUS || GET_CODE (op1) == MINUS)
3600 && (tem = simplify_plus_minus (code, mode, op0, op1)) != 0)
3606 /* Convert (compare FOO (const_int 0)) to FOO unless we aren't
3607 using cc0, in which case we want to leave it as a COMPARE
3608 so we can distinguish it from a register-register-copy.
3610 In IEEE floating point, x-0 is not the same as x. */
3612 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3613 || ! FLOAT_MODE_P (mode) || flag_fast_math)
3614 && op1 == CONST0_RTX (mode))
3617 /* Do nothing here. */
3622 /* None of these optimizations can be done for IEEE
3624 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
3625 && FLOAT_MODE_P (mode) && ! flag_fast_math)
3628 /* We can't assume x-x is 0 even with non-IEEE floating point,
3629 but since it is zero except in very strange circumstances, we
3630 will treat it as zero with -ffast-math. */
3631 if (rtx_equal_p (op0, op1)
3632 && ! side_effects_p (op0)
3633 && (! FLOAT_MODE_P (mode) || flag_fast_math))
3634 return CONST0_RTX (mode);
3636 /* Change subtraction from zero into negation. */
3637 if (op0 == CONST0_RTX (mode))
3638 return gen_rtx (NEG, mode, op1);
3640 /* (-1 - a) is ~a. */
3641 if (op0 == constm1_rtx)
3642 return gen_rtx (NOT, mode, op1);
3644 /* Subtracting 0 has no effect. */
3645 if (op1 == CONST0_RTX (mode))
3648 /* See if this is something like X * C - X or vice versa or
3649 if the multiplication is written as a shift. If so, we can
3650 distribute and make a new multiply, shift, or maybe just
3651 have X (if C is 2 in the example above). But don't make
3652 real multiply if we didn't have one before. */
3654 if (! FLOAT_MODE_P (mode))
3656 HOST_WIDE_INT coeff0 = 1, coeff1 = 1;
3657 rtx lhs = op0, rhs = op1;
3660 if (GET_CODE (lhs) == NEG)
3661 coeff0 = -1, lhs = XEXP (lhs, 0);
3662 else if (GET_CODE (lhs) == MULT
3663 && GET_CODE (XEXP (lhs, 1)) == CONST_INT)
3665 coeff0 = INTVAL (XEXP (lhs, 1)), lhs = XEXP (lhs, 0);
3668 else if (GET_CODE (lhs) == ASHIFT
3669 && GET_CODE (XEXP (lhs, 1)) == CONST_INT
3670 && INTVAL (XEXP (lhs, 1)) >= 0
3671 && INTVAL (XEXP (lhs, 1)) < HOST_BITS_PER_WIDE_INT)
3673 coeff0 = ((HOST_WIDE_INT) 1) << INTVAL (XEXP (lhs, 1));
3674 lhs = XEXP (lhs, 0);
3677 if (GET_CODE (rhs) == NEG)
3678 coeff1 = - 1, rhs = XEXP (rhs, 0);
3679 else if (GET_CODE (rhs) == MULT
3680 && GET_CODE (XEXP (rhs, 1)) == CONST_INT)
3682 coeff1 = INTVAL (XEXP (rhs, 1)), rhs = XEXP (rhs, 0);
3685 else if (GET_CODE (rhs) == ASHIFT
3686 && GET_CODE (XEXP (rhs, 1)) == CONST_INT
3687 && INTVAL (XEXP (rhs, 1)) >= 0
3688 && INTVAL (XEXP (rhs, 1)) < HOST_BITS_PER_WIDE_INT)
3690 coeff1 = ((HOST_WIDE_INT) 1) << INTVAL (XEXP (rhs, 1));
3691 rhs = XEXP (rhs, 0);
3694 if (rtx_equal_p (lhs, rhs))
3696 tem = cse_gen_binary (MULT, mode, lhs,
3697 GEN_INT (coeff0 - coeff1));
3698 return (GET_CODE (tem) == MULT && ! had_mult) ? 0 : tem;
3702 /* (a - (-b)) -> (a + b). */
3703 if (GET_CODE (op1) == NEG)
3704 return cse_gen_binary (PLUS, mode, op0, XEXP (op1, 0));
3706 /* If one of the operands is a PLUS or a MINUS, see if we can
3707 simplify this by the associative law.
3708 Don't use the associative law for floating point.
3709 The inaccuracy makes it nonassociative,
3710 and subtle programs can break if operations are associated. */
3712 if (INTEGRAL_MODE_P (mode)
3713 && (GET_CODE (op0) == PLUS || GET_CODE (op0) == MINUS
3714 || GET_CODE (op1) == PLUS || GET_CODE (op1) == MINUS)
3715 && (tem = simplify_plus_minus (code, mode, op0, op1)) != 0)
3718 /* Don't let a relocatable value get a negative coeff. */
3719 if (GET_CODE (op1) == CONST_INT && GET_MODE (op0) != VOIDmode)
3720 return plus_constant (op0, - INTVAL (op1));
3724 if (op1 == constm1_rtx)
3726 tem = simplify_unary_operation (NEG, mode, op0, mode);
3728 return tem ? tem : gen_rtx (NEG, mode, op0);
3731 /* In IEEE floating point, x*0 is not always 0. */
3732 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3733 || ! FLOAT_MODE_P (mode) || flag_fast_math)
3734 && op1 == CONST0_RTX (mode)
3735 && ! side_effects_p (op0))
3738 /* In IEEE floating point, x*1 is not equivalent to x for nans.
3739 However, ANSI says we can drop signals,
3740 so we can do this anyway. */
3741 if (op1 == CONST1_RTX (mode))
3744 /* Convert multiply by constant power of two into shift unless
3745 we are still generating RTL. This test is a kludge. */
3746 if (GET_CODE (op1) == CONST_INT
3747 && (val = exact_log2 (INTVAL (op1))) >= 0
3748 && ! rtx_equal_function_value_matters)
3749 return gen_rtx (ASHIFT, mode, op0, GEN_INT (val));
3751 if (GET_CODE (op1) == CONST_DOUBLE
3752 && GET_MODE_CLASS (GET_MODE (op1)) == MODE_FLOAT)
3756 int op1is2, op1ism1;
3758 if (setjmp (handler))
3761 set_float_handler (handler);
3762 REAL_VALUE_FROM_CONST_DOUBLE (d, op1);
3763 op1is2 = REAL_VALUES_EQUAL (d, dconst2);
3764 op1ism1 = REAL_VALUES_EQUAL (d, dconstm1);
3765 set_float_handler (NULL_PTR);
3767 /* x*2 is x+x and x*(-1) is -x */
3768 if (op1is2 && GET_MODE (op0) == mode)
3769 return gen_rtx (PLUS, mode, op0, copy_rtx (op0));
3771 else if (op1ism1 && GET_MODE (op0) == mode)
3772 return gen_rtx (NEG, mode, op0);
3777 if (op1 == const0_rtx)
3779 if (GET_CODE (op1) == CONST_INT
3780 && (INTVAL (op1) & GET_MODE_MASK (mode)) == GET_MODE_MASK (mode))
3782 if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3784 /* A | (~A) -> -1 */
3785 if (((GET_CODE (op0) == NOT && rtx_equal_p (XEXP (op0, 0), op1))
3786 || (GET_CODE (op1) == NOT && rtx_equal_p (XEXP (op1, 0), op0)))
3787 && ! side_effects_p (op0)
3788 && GET_MODE_CLASS (mode) != MODE_CC)
3793 if (op1 == const0_rtx)
3795 if (GET_CODE (op1) == CONST_INT
3796 && (INTVAL (op1) & GET_MODE_MASK (mode)) == GET_MODE_MASK (mode))
3797 return gen_rtx (NOT, mode, op0);
3798 if (op0 == op1 && ! side_effects_p (op0)
3799 && GET_MODE_CLASS (mode) != MODE_CC)
3804 if (op1 == const0_rtx && ! side_effects_p (op0))
3806 if (GET_CODE (op1) == CONST_INT
3807 && (INTVAL (op1) & GET_MODE_MASK (mode)) == GET_MODE_MASK (mode))
3809 if (op0 == op1 && ! side_effects_p (op0)
3810 && GET_MODE_CLASS (mode) != MODE_CC)
3813 if (((GET_CODE (op0) == NOT && rtx_equal_p (XEXP (op0, 0), op1))
3814 || (GET_CODE (op1) == NOT && rtx_equal_p (XEXP (op1, 0), op0)))
3815 && ! side_effects_p (op0)
3816 && GET_MODE_CLASS (mode) != MODE_CC)
3821 /* Convert divide by power of two into shift (divide by 1 handled
3823 if (GET_CODE (op1) == CONST_INT
3824 && (arg1 = exact_log2 (INTVAL (op1))) > 0)
3825 return gen_rtx (LSHIFTRT, mode, op0, GEN_INT (arg1));
3827 /* ... fall through ... */
3830 if (op1 == CONST1_RTX (mode))
3833 /* In IEEE floating point, 0/x is not always 0. */
3834 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3835 || ! FLOAT_MODE_P (mode) || flag_fast_math)
3836 && op0 == CONST0_RTX (mode)
3837 && ! side_effects_p (op1))
3840 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3841 /* Change division by a constant into multiplication. Only do
3842 this with -ffast-math until an expert says it is safe in
3844 else if (GET_CODE (op1) == CONST_DOUBLE
3845 && GET_MODE_CLASS (GET_MODE (op1)) == MODE_FLOAT
3846 && op1 != CONST0_RTX (mode)
3850 REAL_VALUE_FROM_CONST_DOUBLE (d, op1);
3852 if (! REAL_VALUES_EQUAL (d, dconst0))
3854 #if defined (REAL_ARITHMETIC)
3855 REAL_ARITHMETIC (d, rtx_to_tree_code (DIV), dconst1, d);
3856 return gen_rtx (MULT, mode, op0,
3857 CONST_DOUBLE_FROM_REAL_VALUE (d, mode));
3859 return gen_rtx (MULT, mode, op0,
3860 CONST_DOUBLE_FROM_REAL_VALUE (1./d, mode));
3868 /* Handle modulus by power of two (mod with 1 handled below). */
3869 if (GET_CODE (op1) == CONST_INT
3870 && exact_log2 (INTVAL (op1)) > 0)
3871 return gen_rtx (AND, mode, op0, GEN_INT (INTVAL (op1) - 1));
3873 /* ... fall through ... */
3876 if ((op0 == const0_rtx || op1 == const1_rtx)
3877 && ! side_effects_p (op0) && ! side_effects_p (op1))
3883 /* Rotating ~0 always results in ~0. */
3884 if (GET_CODE (op0) == CONST_INT && width <= HOST_BITS_PER_WIDE_INT
3885 && INTVAL (op0) == GET_MODE_MASK (mode)
3886 && ! side_effects_p (op1))
3889 /* ... fall through ... */
3894 if (op1 == const0_rtx)
3896 if (op0 == const0_rtx && ! side_effects_p (op1))
3901 if (width <= HOST_BITS_PER_WIDE_INT && GET_CODE (op1) == CONST_INT
3902 && INTVAL (op1) == (HOST_WIDE_INT) 1 << (width -1)
3903 && ! side_effects_p (op0))
3905 else if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3910 if (width <= HOST_BITS_PER_WIDE_INT && GET_CODE (op1) == CONST_INT
3912 == (unsigned HOST_WIDE_INT) GET_MODE_MASK (mode) >> 1)
3913 && ! side_effects_p (op0))
3915 else if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3920 if (op1 == const0_rtx && ! side_effects_p (op0))
3922 else if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3927 if (op1 == constm1_rtx && ! side_effects_p (op0))
3929 else if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3940 /* Get the integer argument values in two forms:
3941 zero-extended in ARG0, ARG1 and sign-extended in ARG0S, ARG1S. */
3943 arg0 = INTVAL (op0);
3944 arg1 = INTVAL (op1);
3946 if (width < HOST_BITS_PER_WIDE_INT)
3948 arg0 &= ((HOST_WIDE_INT) 1 << width) - 1;
3949 arg1 &= ((HOST_WIDE_INT) 1 << width) - 1;
3952 if (arg0s & ((HOST_WIDE_INT) 1 << (width - 1)))
3953 arg0s |= ((HOST_WIDE_INT) (-1) << width);
3956 if (arg1s & ((HOST_WIDE_INT) 1 << (width - 1)))
3957 arg1s |= ((HOST_WIDE_INT) (-1) << width);
3965 /* Compute the value of the arithmetic. */
3970 val = arg0s + arg1s;
3974 val = arg0s - arg1s;
3978 val = arg0s * arg1s;
3984 val = arg0s / arg1s;
3990 val = arg0s % arg1s;
3996 val = (unsigned HOST_WIDE_INT) arg0 / arg1;
4002 val = (unsigned HOST_WIDE_INT) arg0 % arg1;
4018 /* If shift count is undefined, don't fold it; let the machine do
4019 what it wants. But truncate it if the machine will do that. */
4023 #ifdef SHIFT_COUNT_TRUNCATED
4024 if (SHIFT_COUNT_TRUNCATED)
4028 val = ((unsigned HOST_WIDE_INT) arg0) >> arg1;
4035 #ifdef SHIFT_COUNT_TRUNCATED
4036 if (SHIFT_COUNT_TRUNCATED)
4040 val = ((unsigned HOST_WIDE_INT) arg0) << arg1;
4047 #ifdef SHIFT_COUNT_TRUNCATED
4048 if (SHIFT_COUNT_TRUNCATED)
4052 val = arg0s >> arg1;
4054 /* Bootstrap compiler may not have sign extended the right shift.
4055 Manually extend the sign to insure bootstrap cc matches gcc. */
4056 if (arg0s < 0 && arg1 > 0)
4057 val |= ((HOST_WIDE_INT) -1) << (HOST_BITS_PER_WIDE_INT - arg1);
4066 val = ((((unsigned HOST_WIDE_INT) arg0) << (width - arg1))
4067 | (((unsigned HOST_WIDE_INT) arg0) >> arg1));
4075 val = ((((unsigned HOST_WIDE_INT) arg0) << arg1)
4076 | (((unsigned HOST_WIDE_INT) arg0) >> (width - arg1)));
4080 /* Do nothing here. */
4084 val = arg0s <= arg1s ? arg0s : arg1s;
4088 val = ((unsigned HOST_WIDE_INT) arg0
4089 <= (unsigned HOST_WIDE_INT) arg1 ? arg0 : arg1);
4093 val = arg0s > arg1s ? arg0s : arg1s;
4097 val = ((unsigned HOST_WIDE_INT) arg0
4098 > (unsigned HOST_WIDE_INT) arg1 ? arg0 : arg1);
4105 /* Clear the bits that don't belong in our mode, unless they and our sign
4106 bit are all one. So we get either a reasonable negative value or a
4107 reasonable unsigned value for this mode. */
4108 if (width < HOST_BITS_PER_WIDE_INT
4109 && ((val & ((HOST_WIDE_INT) (-1) << (width - 1)))
4110 != ((HOST_WIDE_INT) (-1) << (width - 1))))
4111 val &= ((HOST_WIDE_INT) 1 << width) - 1;
4113 return GEN_INT (val);
4116 /* Simplify a PLUS or MINUS, at least one of whose operands may be another
4119 Rather than test for specific case, we do this by a brute-force method
4120 and do all possible simplifications until no more changes occur. Then
4121 we rebuild the operation. */
4124 simplify_plus_minus (code, mode, op0, op1)
4126 enum machine_mode mode;
4132 int n_ops = 2, input_ops = 2, input_consts = 0, n_consts = 0;
4133 int first = 1, negate = 0, changed;
4136 bzero ((char *) ops, sizeof ops);
4138 /* Set up the two operands and then expand them until nothing has been
4139 changed. If we run out of room in our array, give up; this should
4140 almost never happen. */
4142 ops[0] = op0, ops[1] = op1, negs[0] = 0, negs[1] = (code == MINUS);
4149 for (i = 0; i < n_ops; i++)
4150 switch (GET_CODE (ops[i]))
4157 ops[n_ops] = XEXP (ops[i], 1);
4158 negs[n_ops++] = GET_CODE (ops[i]) == MINUS ? !negs[i] : negs[i];
4159 ops[i] = XEXP (ops[i], 0);
4165 ops[i] = XEXP (ops[i], 0);
4166 negs[i] = ! negs[i];
4171 ops[i] = XEXP (ops[i], 0);
4177 /* ~a -> (-a - 1) */
4180 ops[n_ops] = constm1_rtx;
4181 negs[n_ops++] = negs[i];
4182 ops[i] = XEXP (ops[i], 0);
4183 negs[i] = ! negs[i];
4190 ops[i] = GEN_INT (- INTVAL (ops[i])), negs[i] = 0, changed = 1;
4195 /* If we only have two operands, we can't do anything. */
4199 /* Now simplify each pair of operands until nothing changes. The first
4200 time through just simplify constants against each other. */
4207 for (i = 0; i < n_ops - 1; i++)
4208 for (j = i + 1; j < n_ops; j++)
4209 if (ops[i] != 0 && ops[j] != 0
4210 && (! first || (CONSTANT_P (ops[i]) && CONSTANT_P (ops[j]))))
4212 rtx lhs = ops[i], rhs = ops[j];
4213 enum rtx_code ncode = PLUS;
4215 if (negs[i] && ! negs[j])
4216 lhs = ops[j], rhs = ops[i], ncode = MINUS;
4217 else if (! negs[i] && negs[j])
4220 tem = simplify_binary_operation (ncode, mode, lhs, rhs);
4223 ops[i] = tem, ops[j] = 0;
4224 negs[i] = negs[i] && negs[j];
4225 if (GET_CODE (tem) == NEG)
4226 ops[i] = XEXP (tem, 0), negs[i] = ! negs[i];
4228 if (GET_CODE (ops[i]) == CONST_INT && negs[i])
4229 ops[i] = GEN_INT (- INTVAL (ops[i])), negs[i] = 0;
4237 /* Pack all the operands to the lower-numbered entries and give up if
4238 we didn't reduce the number of operands we had. Make sure we
4239 count a CONST as two operands. If we have the same number of
4240 operands, but have made more CONSTs than we had, this is also
4241 an improvement, so accept it. */
4243 for (i = 0, j = 0; j < n_ops; j++)
4246 ops[i] = ops[j], negs[i++] = negs[j];
4247 if (GET_CODE (ops[j]) == CONST)
4251 if (i + n_consts > input_ops
4252 || (i + n_consts == input_ops && n_consts <= input_consts))
4257 /* If we have a CONST_INT, put it last. */
4258 for (i = 0; i < n_ops - 1; i++)
4259 if (GET_CODE (ops[i]) == CONST_INT)
4261 tem = ops[n_ops - 1], ops[n_ops - 1] = ops[i] , ops[i] = tem;
4262 j = negs[n_ops - 1], negs[n_ops - 1] = negs[i], negs[i] = j;
4265 /* Put a non-negated operand first. If there aren't any, make all
4266 operands positive and negate the whole thing later. */
4267 for (i = 0; i < n_ops && negs[i]; i++)
4272 for (i = 0; i < n_ops; i++)
4278 tem = ops[0], ops[0] = ops[i], ops[i] = tem;
4279 j = negs[0], negs[0] = negs[i], negs[i] = j;
4282 /* Now make the result by performing the requested operations. */
4284 for (i = 1; i < n_ops; i++)
4285 result = cse_gen_binary (negs[i] ? MINUS : PLUS, mode, result, ops[i]);
4287 return negate ? gen_rtx (NEG, mode, result) : result;
4290 /* Make a binary operation by properly ordering the operands and
4291 seeing if the expression folds. */
4294 cse_gen_binary (code, mode, op0, op1)
4296 enum machine_mode mode;
4301 /* Put complex operands first and constants second if commutative. */
4302 if (GET_RTX_CLASS (code) == 'c'
4303 && ((CONSTANT_P (op0) && GET_CODE (op1) != CONST_INT)
4304 || (GET_RTX_CLASS (GET_CODE (op0)) == 'o'
4305 && GET_RTX_CLASS (GET_CODE (op1)) != 'o')
4306 || (GET_CODE (op0) == SUBREG
4307 && GET_RTX_CLASS (GET_CODE (SUBREG_REG (op0))) == 'o'
4308 && GET_RTX_CLASS (GET_CODE (op1)) != 'o')))
4309 tem = op0, op0 = op1, op1 = tem;
4311 /* If this simplifies, do it. */
4312 tem = simplify_binary_operation (code, mode, op0, op1);
4317 /* Handle addition and subtraction of CONST_INT specially. Otherwise,
4318 just form the operation. */
4320 if (code == PLUS && GET_CODE (op1) == CONST_INT
4321 && GET_MODE (op0) != VOIDmode)
4322 return plus_constant (op0, INTVAL (op1));
4323 else if (code == MINUS && GET_CODE (op1) == CONST_INT
4324 && GET_MODE (op0) != VOIDmode)
4325 return plus_constant (op0, - INTVAL (op1));
4327 return gen_rtx (code, mode, op0, op1);
4330 /* Like simplify_binary_operation except used for relational operators.
4331 MODE is the mode of the operands, not that of the result. If MODE
4332 is VOIDmode, both operands must also be VOIDmode and we compare the
4333 operands in "infinite precision".
4335 If no simplification is possible, this function returns zero. Otherwise,
4336 it returns either const_true_rtx or const0_rtx. */
4339 simplify_relational_operation (code, mode, op0, op1)
4341 enum machine_mode mode;
4344 int equal, op0lt, op0ltu, op1lt, op1ltu;
4347 /* If op0 is a compare, extract the comparison arguments from it. */
4348 if (GET_CODE (op0) == COMPARE && op1 == const0_rtx)
4349 op1 = XEXP (op0, 1), op0 = XEXP (op0, 0);
4351 /* We can't simplify MODE_CC values since we don't know what the
4352 actual comparison is. */
4353 if (GET_MODE_CLASS (GET_MODE (op0)) == MODE_CC
4360 /* For integer comparisons of A and B maybe we can simplify A - B and can
4361 then simplify a comparison of that with zero. If A and B are both either
4362 a register or a CONST_INT, this can't help; testing for these cases will
4363 prevent infinite recursion here and speed things up.
4365 If CODE is an unsigned comparison, we can only do this if A - B is a
4366 constant integer, and then we have to compare that integer with zero as a
4367 signed comparison. Note that this will give the incorrect result from
4368 comparisons that overflow. Since these are undefined, this is probably
4369 OK. If it causes a problem, we can check for A or B being an address
4370 (fp + const or SYMBOL_REF) and only do it in that case. */
4372 if (INTEGRAL_MODE_P (mode) && op1 != const0_rtx
4373 && ! ((GET_CODE (op0) == REG || GET_CODE (op0) == CONST_INT)
4374 && (GET_CODE (op1) == REG || GET_CODE (op1) == CONST_INT))
4375 && 0 != (tem = simplify_binary_operation (MINUS, mode, op0, op1))
4376 && (GET_CODE (tem) == CONST_INT
4377 || (code != GTU && code != GEU &&
4378 code != LTU && code != LEU)))
4379 return simplify_relational_operation (signed_condition (code),
4380 mode, tem, const0_rtx);
4382 /* For non-IEEE floating-point, if the two operands are equal, we know the
4384 if (rtx_equal_p (op0, op1)
4385 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4386 || ! FLOAT_MODE_P (GET_MODE (op0)) || flag_fast_math))
4387 equal = 1, op0lt = 0, op0ltu = 0, op1lt = 0, op1ltu = 0;
4389 /* If the operands are floating-point constants, see if we can fold
4391 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4392 else if (GET_CODE (op0) == CONST_DOUBLE && GET_CODE (op1) == CONST_DOUBLE
4393 && GET_MODE_CLASS (GET_MODE (op0)) == MODE_FLOAT)
4395 REAL_VALUE_TYPE d0, d1;
4398 if (setjmp (handler))
4401 set_float_handler (handler);
4402 REAL_VALUE_FROM_CONST_DOUBLE (d0, op0);
4403 REAL_VALUE_FROM_CONST_DOUBLE (d1, op1);
4404 equal = REAL_VALUES_EQUAL (d0, d1);
4405 op0lt = op0ltu = REAL_VALUES_LESS (d0, d1);
4406 op1lt = op1ltu = REAL_VALUES_LESS (d1, d0);
4407 set_float_handler (NULL_PTR);
4409 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4411 /* Otherwise, see if the operands are both integers. */
4412 else if ((GET_MODE_CLASS (mode) == MODE_INT || mode == VOIDmode)
4413 && (GET_CODE (op0) == CONST_DOUBLE || GET_CODE (op0) == CONST_INT)
4414 && (GET_CODE (op1) == CONST_DOUBLE || GET_CODE (op1) == CONST_INT))
4416 int width = GET_MODE_BITSIZE (mode);
4417 HOST_WIDE_INT l0s, h0s, l1s, h1s;
4418 unsigned HOST_WIDE_INT l0u, h0u, l1u, h1u;
4420 /* Get the two words comprising each integer constant. */
4421 if (GET_CODE (op0) == CONST_DOUBLE)
4423 l0u = l0s = CONST_DOUBLE_LOW (op0);
4424 h0u = h0s = CONST_DOUBLE_HIGH (op0);
4428 l0u = l0s = INTVAL (op0);
4429 h0u = 0, h0s = l0s < 0 ? -1 : 0;
4432 if (GET_CODE (op1) == CONST_DOUBLE)
4434 l1u = l1s = CONST_DOUBLE_LOW (op1);
4435 h1u = h1s = CONST_DOUBLE_HIGH (op1);
4439 l1u = l1s = INTVAL (op1);
4440 h1u = 0, h1s = l1s < 0 ? -1 : 0;
4443 /* If WIDTH is nonzero and smaller than HOST_BITS_PER_WIDE_INT,
4444 we have to sign or zero-extend the values. */
4445 if (width != 0 && width <= HOST_BITS_PER_WIDE_INT)
4446 h0u = h1u = 0, h0s = l0s < 0 ? -1 : 0, h1s = l1s < 0 ? -1 : 0;
4448 if (width != 0 && width < HOST_BITS_PER_WIDE_INT)
4450 l0u &= ((HOST_WIDE_INT) 1 << width) - 1;
4451 l1u &= ((HOST_WIDE_INT) 1 << width) - 1;
4453 if (l0s & ((HOST_WIDE_INT) 1 << (width - 1)))
4454 l0s |= ((HOST_WIDE_INT) (-1) << width);
4456 if (l1s & ((HOST_WIDE_INT) 1 << (width - 1)))
4457 l1s |= ((HOST_WIDE_INT) (-1) << width);
4460 equal = (h0u == h1u && l0u == l1u);
4461 op0lt = (h0s < h1s || (h0s == h1s && l0s < l1s));
4462 op1lt = (h1s < h0s || (h1s == h0s && l1s < l0s));
4463 op0ltu = (h0u < h1u || (h0u == h1u && l0u < l1u));
4464 op1ltu = (h1u < h0u || (h1u == h0u && l1u < l0u));
4467 /* Otherwise, there are some code-specific tests we can make. */
4473 /* References to the frame plus a constant or labels cannot
4474 be zero, but a SYMBOL_REF can due to #pragma weak. */
4475 if (((NONZERO_BASE_PLUS_P (op0) && op1 == const0_rtx)
4476 || GET_CODE (op0) == LABEL_REF)
4477 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4478 /* On some machines, the ap reg can be 0 sometimes. */
4479 && op0 != arg_pointer_rtx
4486 if (((NONZERO_BASE_PLUS_P (op0) && op1 == const0_rtx)
4487 || GET_CODE (op0) == LABEL_REF)
4488 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4489 && op0 != arg_pointer_rtx
4492 return const_true_rtx;
4496 /* Unsigned values are never negative. */
4497 if (op1 == const0_rtx)
4498 return const_true_rtx;
4502 if (op1 == const0_rtx)
4507 /* Unsigned values are never greater than the largest
4509 if (GET_CODE (op1) == CONST_INT
4510 && INTVAL (op1) == GET_MODE_MASK (mode)
4511 && INTEGRAL_MODE_P (mode))
4512 return const_true_rtx;
4516 if (GET_CODE (op1) == CONST_INT
4517 && INTVAL (op1) == GET_MODE_MASK (mode)
4518 && INTEGRAL_MODE_P (mode))
4526 /* If we reach here, EQUAL, OP0LT, OP0LTU, OP1LT, and OP1LTU are set
4531 return equal ? const_true_rtx : const0_rtx;
4533 return ! equal ? const_true_rtx : const0_rtx;
4535 return op0lt ? const_true_rtx : const0_rtx;
4537 return op1lt ? const_true_rtx : const0_rtx;
4539 return op0ltu ? const_true_rtx : const0_rtx;
4541 return op1ltu ? const_true_rtx : const0_rtx;
4543 return equal || op0lt ? const_true_rtx : const0_rtx;
4545 return equal || op1lt ? const_true_rtx : const0_rtx;
4547 return equal || op0ltu ? const_true_rtx : const0_rtx;
4549 return equal || op1ltu ? const_true_rtx : const0_rtx;
4555 /* Simplify CODE, an operation with result mode MODE and three operands,
4556 OP0, OP1, and OP2. OP0_MODE was the mode of OP0 before it became
4557 a constant. Return 0 if no simplifications is possible. */
4560 simplify_ternary_operation (code, mode, op0_mode, op0, op1, op2)
4562 enum machine_mode mode, op0_mode;
4565 int width = GET_MODE_BITSIZE (mode);
4567 /* VOIDmode means "infinite" precision. */
4569 width = HOST_BITS_PER_WIDE_INT;
4575 if (GET_CODE (op0) == CONST_INT
4576 && GET_CODE (op1) == CONST_INT
4577 && GET_CODE (op2) == CONST_INT
4578 && INTVAL (op1) + INTVAL (op2) <= GET_MODE_BITSIZE (op0_mode)
4579 && width <= HOST_BITS_PER_WIDE_INT)
4581 /* Extracting a bit-field from a constant */
4582 HOST_WIDE_INT val = INTVAL (op0);
4584 if (BITS_BIG_ENDIAN)
4585 val >>= (GET_MODE_BITSIZE (op0_mode)
4586 - INTVAL (op2) - INTVAL (op1));
4588 val >>= INTVAL (op2);
4590 if (HOST_BITS_PER_WIDE_INT != INTVAL (op1))
4592 /* First zero-extend. */
4593 val &= ((HOST_WIDE_INT) 1 << INTVAL (op1)) - 1;
4594 /* If desired, propagate sign bit. */
4595 if (code == SIGN_EXTRACT
4596 && (val & ((HOST_WIDE_INT) 1 << (INTVAL (op1) - 1))))
4597 val |= ~ (((HOST_WIDE_INT) 1 << INTVAL (op1)) - 1);
4600 /* Clear the bits that don't belong in our mode,
4601 unless they and our sign bit are all one.
4602 So we get either a reasonable negative value or a reasonable
4603 unsigned value for this mode. */
4604 if (width < HOST_BITS_PER_WIDE_INT
4605 && ((val & ((HOST_WIDE_INT) (-1) << (width - 1)))
4606 != ((HOST_WIDE_INT) (-1) << (width - 1))))
4607 val &= ((HOST_WIDE_INT) 1 << width) - 1;
4609 return GEN_INT (val);
4614 if (GET_CODE (op0) == CONST_INT)
4615 return op0 != const0_rtx ? op1 : op2;
4625 /* If X is a nontrivial arithmetic operation on an argument
4626 for which a constant value can be determined, return
4627 the result of operating on that value, as a constant.
4628 Otherwise, return X, possibly with one or more operands
4629 modified by recursive calls to this function.
4631 If X is a register whose contents are known, we do NOT
4632 return those contents here. equiv_constant is called to
4635 INSN is the insn that we may be modifying. If it is 0, make a copy
4636 of X before modifying it. */
4643 register enum rtx_code code;
4644 register enum machine_mode mode;
4651 /* Folded equivalents of first two operands of X. */
4655 /* Constant equivalents of first three operands of X;
4656 0 when no such equivalent is known. */
4661 /* The mode of the first operand of X. We need this for sign and zero
4663 enum machine_mode mode_arg0;
4668 mode = GET_MODE (x);
4669 code = GET_CODE (x);
4678 /* No use simplifying an EXPR_LIST
4679 since they are used only for lists of args
4680 in a function call's REG_EQUAL note. */
4686 return prev_insn_cc0;
4690 /* If the next insn is a CODE_LABEL followed by a jump table,
4691 PC's value is a LABEL_REF pointing to that label. That
4692 lets us fold switch statements on the Vax. */
4693 if (insn && GET_CODE (insn) == JUMP_INSN)
4695 rtx next = next_nonnote_insn (insn);
4697 if (next && GET_CODE (next) == CODE_LABEL
4698 && NEXT_INSN (next) != 0
4699 && GET_CODE (NEXT_INSN (next)) == JUMP_INSN
4700 && (GET_CODE (PATTERN (NEXT_INSN (next))) == ADDR_VEC
4701 || GET_CODE (PATTERN (NEXT_INSN (next))) == ADDR_DIFF_VEC))
4702 return gen_rtx (LABEL_REF, Pmode, next);
4707 /* See if we previously assigned a constant value to this SUBREG. */
4708 if ((new = lookup_as_function (x, CONST_INT)) != 0
4709 || (new = lookup_as_function (x, CONST_DOUBLE)) != 0)
4712 /* If this is a paradoxical SUBREG, we have no idea what value the
4713 extra bits would have. However, if the operand is equivalent
4714 to a SUBREG whose operand is the same as our mode, and all the
4715 modes are within a word, we can just use the inner operand
4716 because these SUBREGs just say how to treat the register.
4718 Similarly if we find an integer constant. */
4720 if (GET_MODE_SIZE (mode) > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
4722 enum machine_mode imode = GET_MODE (SUBREG_REG (x));
4723 struct table_elt *elt;
4725 if (GET_MODE_SIZE (mode) <= UNITS_PER_WORD
4726 && GET_MODE_SIZE (imode) <= UNITS_PER_WORD
4727 && (elt = lookup (SUBREG_REG (x), HASH (SUBREG_REG (x), imode),
4729 for (elt = elt->first_same_value;
4730 elt; elt = elt->next_same_value)
4732 if (CONSTANT_P (elt->exp)
4733 && GET_MODE (elt->exp) == VOIDmode)
4736 if (GET_CODE (elt->exp) == SUBREG
4737 && GET_MODE (SUBREG_REG (elt->exp)) == mode
4738 && exp_equiv_p (elt->exp, elt->exp, 1, 0))
4739 return copy_rtx (SUBREG_REG (elt->exp));
4745 /* Fold SUBREG_REG. If it changed, see if we can simplify the SUBREG.
4746 We might be able to if the SUBREG is extracting a single word in an
4747 integral mode or extracting the low part. */
4749 folded_arg0 = fold_rtx (SUBREG_REG (x), insn);
4750 const_arg0 = equiv_constant (folded_arg0);
4752 folded_arg0 = const_arg0;
4754 if (folded_arg0 != SUBREG_REG (x))
4758 if (GET_MODE_CLASS (mode) == MODE_INT
4759 && GET_MODE_SIZE (mode) == UNITS_PER_WORD
4760 && GET_MODE (SUBREG_REG (x)) != VOIDmode)
4761 new = operand_subword (folded_arg0, SUBREG_WORD (x), 0,
4762 GET_MODE (SUBREG_REG (x)));
4763 if (new == 0 && subreg_lowpart_p (x))
4764 new = gen_lowpart_if_possible (mode, folded_arg0);
4769 /* If this is a narrowing SUBREG and our operand is a REG, see if
4770 we can find an equivalence for REG that is an arithmetic operation
4771 in a wider mode where both operands are paradoxical SUBREGs
4772 from objects of our result mode. In that case, we couldn't report
4773 an equivalent value for that operation, since we don't know what the
4774 extra bits will be. But we can find an equivalence for this SUBREG
4775 by folding that operation is the narrow mode. This allows us to
4776 fold arithmetic in narrow modes when the machine only supports
4777 word-sized arithmetic.
4779 Also look for a case where we have a SUBREG whose operand is the
4780 same as our result. If both modes are smaller than a word, we
4781 are simply interpreting a register in different modes and we
4782 can use the inner value. */
4784 if (GET_CODE (folded_arg0) == REG
4785 && GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (folded_arg0))
4786 && subreg_lowpart_p (x))
4788 struct table_elt *elt;
4790 /* We can use HASH here since we know that canon_hash won't be
4792 elt = lookup (folded_arg0,
4793 HASH (folded_arg0, GET_MODE (folded_arg0)),
4794 GET_MODE (folded_arg0));
4797 elt = elt->first_same_value;
4799 for (; elt; elt = elt->next_same_value)
4801 enum rtx_code eltcode = GET_CODE (elt->exp);
4803 /* Just check for unary and binary operations. */
4804 if (GET_RTX_CLASS (GET_CODE (elt->exp)) == '1'
4805 && GET_CODE (elt->exp) != SIGN_EXTEND
4806 && GET_CODE (elt->exp) != ZERO_EXTEND
4807 && GET_CODE (XEXP (elt->exp, 0)) == SUBREG
4808 && GET_MODE (SUBREG_REG (XEXP (elt->exp, 0))) == mode)
4810 rtx op0 = SUBREG_REG (XEXP (elt->exp, 0));
4812 if (GET_CODE (op0) != REG && ! CONSTANT_P (op0))
4813 op0 = fold_rtx (op0, NULL_RTX);
4815 op0 = equiv_constant (op0);
4817 new = simplify_unary_operation (GET_CODE (elt->exp), mode,
4820 else if ((GET_RTX_CLASS (GET_CODE (elt->exp)) == '2'
4821 || GET_RTX_CLASS (GET_CODE (elt->exp)) == 'c')
4822 && eltcode != DIV && eltcode != MOD
4823 && eltcode != UDIV && eltcode != UMOD
4824 && eltcode != ASHIFTRT && eltcode != LSHIFTRT
4825 && eltcode != ROTATE && eltcode != ROTATERT
4826 && ((GET_CODE (XEXP (elt->exp, 0)) == SUBREG
4827 && (GET_MODE (SUBREG_REG (XEXP (elt->exp, 0)))
4829 || CONSTANT_P (XEXP (elt->exp, 0)))
4830 && ((GET_CODE (XEXP (elt->exp, 1)) == SUBREG
4831 && (GET_MODE (SUBREG_REG (XEXP (elt->exp, 1)))
4833 || CONSTANT_P (XEXP (elt->exp, 1))))
4835 rtx op0 = gen_lowpart_common (mode, XEXP (elt->exp, 0));
4836 rtx op1 = gen_lowpart_common (mode, XEXP (elt->exp, 1));
4838 if (op0 && GET_CODE (op0) != REG && ! CONSTANT_P (op0))
4839 op0 = fold_rtx (op0, NULL_RTX);
4842 op0 = equiv_constant (op0);
4844 if (op1 && GET_CODE (op1) != REG && ! CONSTANT_P (op1))
4845 op1 = fold_rtx (op1, NULL_RTX);
4848 op1 = equiv_constant (op1);
4850 /* If we are looking for the low SImode part of
4851 (ashift:DI c (const_int 32)), it doesn't work
4852 to compute that in SImode, because a 32-bit shift
4853 in SImode is unpredictable. We know the value is 0. */
4855 && GET_CODE (elt->exp) == ASHIFT
4856 && GET_CODE (op1) == CONST_INT
4857 && INTVAL (op1) >= GET_MODE_BITSIZE (mode))
4859 if (INTVAL (op1) < GET_MODE_BITSIZE (GET_MODE (elt->exp)))
4861 /* If the count fits in the inner mode's width,
4862 but exceeds the outer mode's width,
4863 the value will get truncated to 0
4867 /* If the count exceeds even the inner mode's width,
4868 don't fold this expression. */
4871 else if (op0 && op1)
4872 new = simplify_binary_operation (GET_CODE (elt->exp), mode,
4876 else if (GET_CODE (elt->exp) == SUBREG
4877 && GET_MODE (SUBREG_REG (elt->exp)) == mode
4878 && (GET_MODE_SIZE (GET_MODE (folded_arg0))
4880 && exp_equiv_p (elt->exp, elt->exp, 1, 0))
4881 new = copy_rtx (SUBREG_REG (elt->exp));
4892 /* If we have (NOT Y), see if Y is known to be (NOT Z).
4893 If so, (NOT Y) simplifies to Z. Similarly for NEG. */
4894 new = lookup_as_function (XEXP (x, 0), code);
4896 return fold_rtx (copy_rtx (XEXP (new, 0)), insn);
4900 /* If we are not actually processing an insn, don't try to find the
4901 best address. Not only don't we care, but we could modify the
4902 MEM in an invalid way since we have no insn to validate against. */
4904 find_best_addr (insn, &XEXP (x, 0));
4907 /* Even if we don't fold in the insn itself,
4908 we can safely do so here, in hopes of getting a constant. */
4909 rtx addr = fold_rtx (XEXP (x, 0), NULL_RTX);
4911 HOST_WIDE_INT offset = 0;
4913 if (GET_CODE (addr) == REG
4914 && REGNO_QTY_VALID_P (REGNO (addr))
4915 && GET_MODE (addr) == qty_mode[reg_qty[REGNO (addr)]]
4916 && qty_const[reg_qty[REGNO (addr)]] != 0)
4917 addr = qty_const[reg_qty[REGNO (addr)]];
4919 /* If address is constant, split it into a base and integer offset. */
4920 if (GET_CODE (addr) == SYMBOL_REF || GET_CODE (addr) == LABEL_REF)
4922 else if (GET_CODE (addr) == CONST && GET_CODE (XEXP (addr, 0)) == PLUS
4923 && GET_CODE (XEXP (XEXP (addr, 0), 1)) == CONST_INT)
4925 base = XEXP (XEXP (addr, 0), 0);
4926 offset = INTVAL (XEXP (XEXP (addr, 0), 1));
4928 else if (GET_CODE (addr) == LO_SUM
4929 && GET_CODE (XEXP (addr, 1)) == SYMBOL_REF)
4930 base = XEXP (addr, 1);
4932 /* If this is a constant pool reference, we can fold it into its
4933 constant to allow better value tracking. */
4934 if (base && GET_CODE (base) == SYMBOL_REF
4935 && CONSTANT_POOL_ADDRESS_P (base))
4937 rtx constant = get_pool_constant (base);
4938 enum machine_mode const_mode = get_pool_mode (base);
4941 if (CONSTANT_P (constant) && GET_CODE (constant) != CONST_INT)
4942 constant_pool_entries_cost = COST (constant);
4944 /* If we are loading the full constant, we have an equivalence. */
4945 if (offset == 0 && mode == const_mode)
4948 /* If this actually isn't a constant (wierd!), we can't do
4949 anything. Otherwise, handle the two most common cases:
4950 extracting a word from a multi-word constant, and extracting
4951 the low-order bits. Other cases don't seem common enough to
4953 if (! CONSTANT_P (constant))
4956 if (GET_MODE_CLASS (mode) == MODE_INT
4957 && GET_MODE_SIZE (mode) == UNITS_PER_WORD
4958 && offset % UNITS_PER_WORD == 0
4959 && (new = operand_subword (constant,
4960 offset / UNITS_PER_WORD,
4961 0, const_mode)) != 0)
4964 if (((BYTES_BIG_ENDIAN
4965 && offset == GET_MODE_SIZE (GET_MODE (constant)) - 1)
4966 || (! BYTES_BIG_ENDIAN && offset == 0))
4967 && (new = gen_lowpart_if_possible (mode, constant)) != 0)
4971 /* If this is a reference to a label at a known position in a jump
4972 table, we also know its value. */
4973 if (base && GET_CODE (base) == LABEL_REF)
4975 rtx label = XEXP (base, 0);
4976 rtx table_insn = NEXT_INSN (label);
4978 if (table_insn && GET_CODE (table_insn) == JUMP_INSN
4979 && GET_CODE (PATTERN (table_insn)) == ADDR_VEC)
4981 rtx table = PATTERN (table_insn);
4984 && (offset / GET_MODE_SIZE (GET_MODE (table))
4985 < XVECLEN (table, 0)))
4986 return XVECEXP (table, 0,
4987 offset / GET_MODE_SIZE (GET_MODE (table)));
4989 if (table_insn && GET_CODE (table_insn) == JUMP_INSN
4990 && GET_CODE (PATTERN (table_insn)) == ADDR_DIFF_VEC)
4992 rtx table = PATTERN (table_insn);
4995 && (offset / GET_MODE_SIZE (GET_MODE (table))
4996 < XVECLEN (table, 1)))
4998 offset /= GET_MODE_SIZE (GET_MODE (table));
4999 new = gen_rtx (MINUS, Pmode, XVECEXP (table, 1, offset),
5002 if (GET_MODE (table) != Pmode)
5003 new = gen_rtx (TRUNCATE, GET_MODE (table), new);
5005 /* Indicate this is a constant. This isn't a
5006 valid form of CONST, but it will only be used
5007 to fold the next insns and then discarded, so
5008 it should be safe. */
5009 return gen_rtx (CONST, GET_MODE (new), new);
5021 mode_arg0 = VOIDmode;
5023 /* Try folding our operands.
5024 Then see which ones have constant values known. */
5026 fmt = GET_RTX_FORMAT (code);
5027 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5030 rtx arg = XEXP (x, i);
5031 rtx folded_arg = arg, const_arg = 0;
5032 enum machine_mode mode_arg = GET_MODE (arg);
5033 rtx cheap_arg, expensive_arg;
5034 rtx replacements[2];
5037 /* Most arguments are cheap, so handle them specially. */
5038 switch (GET_CODE (arg))
5041 /* This is the same as calling equiv_constant; it is duplicated
5043 if (REGNO_QTY_VALID_P (REGNO (arg))
5044 && qty_const[reg_qty[REGNO (arg)]] != 0
5045 && GET_CODE (qty_const[reg_qty[REGNO (arg)]]) != REG
5046 && GET_CODE (qty_const[reg_qty[REGNO (arg)]]) != PLUS)
5048 = gen_lowpart_if_possible (GET_MODE (arg),
5049 qty_const[reg_qty[REGNO (arg)]]);
5062 folded_arg = prev_insn_cc0;
5063 mode_arg = prev_insn_cc0_mode;
5064 const_arg = equiv_constant (folded_arg);
5069 folded_arg = fold_rtx (arg, insn);
5070 const_arg = equiv_constant (folded_arg);
5073 /* For the first three operands, see if the operand
5074 is constant or equivalent to a constant. */
5078 folded_arg0 = folded_arg;
5079 const_arg0 = const_arg;
5080 mode_arg0 = mode_arg;
5083 folded_arg1 = folded_arg;
5084 const_arg1 = const_arg;
5087 const_arg2 = const_arg;
5091 /* Pick the least expensive of the folded argument and an
5092 equivalent constant argument. */
5093 if (const_arg == 0 || const_arg == folded_arg
5094 || COST (const_arg) > COST (folded_arg))
5095 cheap_arg = folded_arg, expensive_arg = const_arg;
5097 cheap_arg = const_arg, expensive_arg = folded_arg;
5099 /* Try to replace the operand with the cheapest of the two
5100 possibilities. If it doesn't work and this is either of the first
5101 two operands of a commutative operation, try swapping them.
5102 If THAT fails, try the more expensive, provided it is cheaper
5103 than what is already there. */
5105 if (cheap_arg == XEXP (x, i))
5108 if (insn == 0 && ! copied)
5114 replacements[0] = cheap_arg, replacements[1] = expensive_arg;
5116 j < 2 && replacements[j]
5117 && COST (replacements[j]) < COST (XEXP (x, i));
5120 if (validate_change (insn, &XEXP (x, i), replacements[j], 0))
5123 if (code == NE || code == EQ || GET_RTX_CLASS (code) == 'c')
5125 validate_change (insn, &XEXP (x, i), XEXP (x, 1 - i), 1);
5126 validate_change (insn, &XEXP (x, 1 - i), replacements[j], 1);
5128 if (apply_change_group ())
5130 /* Swap them back to be invalid so that this loop can
5131 continue and flag them to be swapped back later. */
5134 tem = XEXP (x, 0); XEXP (x, 0) = XEXP (x, 1);
5143 else if (fmt[i] == 'E')
5144 /* Don't try to fold inside of a vector of expressions.
5145 Doing nothing is harmless. */
5148 /* If a commutative operation, place a constant integer as the second
5149 operand unless the first operand is also a constant integer. Otherwise,
5150 place any constant second unless the first operand is also a constant. */
5152 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5154 if (must_swap || (const_arg0
5156 || (GET_CODE (const_arg0) == CONST_INT
5157 && GET_CODE (const_arg1) != CONST_INT))))
5159 register rtx tem = XEXP (x, 0);
5161 if (insn == 0 && ! copied)
5167 validate_change (insn, &XEXP (x, 0), XEXP (x, 1), 1);
5168 validate_change (insn, &XEXP (x, 1), tem, 1);
5169 if (apply_change_group ())
5171 tem = const_arg0, const_arg0 = const_arg1, const_arg1 = tem;
5172 tem = folded_arg0, folded_arg0 = folded_arg1, folded_arg1 = tem;
5177 /* If X is an arithmetic operation, see if we can simplify it. */
5179 switch (GET_RTX_CLASS (code))
5185 /* We can't simplify extension ops unless we know the
5187 if ((code == ZERO_EXTEND || code == SIGN_EXTEND)
5188 && mode_arg0 == VOIDmode)
5191 /* If we had a CONST, strip it off and put it back later if we
5193 if (const_arg0 != 0 && GET_CODE (const_arg0) == CONST)
5194 is_const = 1, const_arg0 = XEXP (const_arg0, 0);
5196 new = simplify_unary_operation (code, mode,
5197 const_arg0 ? const_arg0 : folded_arg0,
5199 if (new != 0 && is_const)
5200 new = gen_rtx (CONST, mode, new);
5205 /* See what items are actually being compared and set FOLDED_ARG[01]
5206 to those values and CODE to the actual comparison code. If any are
5207 constant, set CONST_ARG0 and CONST_ARG1 appropriately. We needn't
5208 do anything if both operands are already known to be constant. */
5210 if (const_arg0 == 0 || const_arg1 == 0)
5212 struct table_elt *p0, *p1;
5213 rtx true = const_true_rtx, false = const0_rtx;
5214 enum machine_mode mode_arg1;
5216 #ifdef FLOAT_STORE_FLAG_VALUE
5217 if (GET_MODE_CLASS (mode) == MODE_FLOAT)
5219 true = CONST_DOUBLE_FROM_REAL_VALUE (FLOAT_STORE_FLAG_VALUE,
5221 false = CONST0_RTX (mode);
5225 code = find_comparison_args (code, &folded_arg0, &folded_arg1,
5226 &mode_arg0, &mode_arg1);
5227 const_arg0 = equiv_constant (folded_arg0);
5228 const_arg1 = equiv_constant (folded_arg1);
5230 /* If the mode is VOIDmode or a MODE_CC mode, we don't know
5231 what kinds of things are being compared, so we can't do
5232 anything with this comparison. */
5234 if (mode_arg0 == VOIDmode || GET_MODE_CLASS (mode_arg0) == MODE_CC)
5237 /* If we do not now have two constants being compared, see if we
5238 can nevertheless deduce some things about the comparison. */
5239 if (const_arg0 == 0 || const_arg1 == 0)
5241 /* Is FOLDED_ARG0 frame-pointer plus a constant? Or non-explicit
5242 constant? These aren't zero, but we don't know their sign. */
5243 if (const_arg1 == const0_rtx
5244 && (NONZERO_BASE_PLUS_P (folded_arg0)
5245 #if 0 /* Sad to say, on sysvr4, #pragma weak can make a symbol address
5247 || GET_CODE (folded_arg0) == SYMBOL_REF
5249 || GET_CODE (folded_arg0) == LABEL_REF
5250 || GET_CODE (folded_arg0) == CONST))
5254 else if (code == NE)
5258 /* See if the two operands are the same. We don't do this
5259 for IEEE floating-point since we can't assume x == x
5260 since x might be a NaN. */
5262 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5263 || ! FLOAT_MODE_P (mode_arg0) || flag_fast_math)
5264 && (folded_arg0 == folded_arg1
5265 || (GET_CODE (folded_arg0) == REG
5266 && GET_CODE (folded_arg1) == REG
5267 && (reg_qty[REGNO (folded_arg0)]
5268 == reg_qty[REGNO (folded_arg1)]))
5269 || ((p0 = lookup (folded_arg0,
5270 (safe_hash (folded_arg0, mode_arg0)
5271 % NBUCKETS), mode_arg0))
5272 && (p1 = lookup (folded_arg1,
5273 (safe_hash (folded_arg1, mode_arg0)
5274 % NBUCKETS), mode_arg0))
5275 && p0->first_same_value == p1->first_same_value)))
5276 return ((code == EQ || code == LE || code == GE
5277 || code == LEU || code == GEU)
5280 /* If FOLDED_ARG0 is a register, see if the comparison we are
5281 doing now is either the same as we did before or the reverse
5282 (we only check the reverse if not floating-point). */
5283 else if (GET_CODE (folded_arg0) == REG)
5285 int qty = reg_qty[REGNO (folded_arg0)];
5287 if (REGNO_QTY_VALID_P (REGNO (folded_arg0))
5288 && (comparison_dominates_p (qty_comparison_code[qty], code)
5289 || (comparison_dominates_p (qty_comparison_code[qty],
5290 reverse_condition (code))
5291 && ! FLOAT_MODE_P (mode_arg0)))
5292 && (rtx_equal_p (qty_comparison_const[qty], folded_arg1)
5294 && rtx_equal_p (qty_comparison_const[qty],
5296 || (GET_CODE (folded_arg1) == REG
5297 && (reg_qty[REGNO (folded_arg1)]
5298 == qty_comparison_qty[qty]))))
5299 return (comparison_dominates_p (qty_comparison_code[qty],
5306 /* If we are comparing against zero, see if the first operand is
5307 equivalent to an IOR with a constant. If so, we may be able to
5308 determine the result of this comparison. */
5310 if (const_arg1 == const0_rtx)
5312 rtx y = lookup_as_function (folded_arg0, IOR);
5316 && (inner_const = equiv_constant (XEXP (y, 1))) != 0
5317 && GET_CODE (inner_const) == CONST_INT
5318 && INTVAL (inner_const) != 0)
5320 int sign_bitnum = GET_MODE_BITSIZE (mode_arg0) - 1;
5321 int has_sign = (HOST_BITS_PER_WIDE_INT >= sign_bitnum
5322 && (INTVAL (inner_const)
5323 & ((HOST_WIDE_INT) 1 << sign_bitnum)));
5324 rtx true = const_true_rtx, false = const0_rtx;
5326 #ifdef FLOAT_STORE_FLAG_VALUE
5327 if (GET_MODE_CLASS (mode) == MODE_FLOAT)
5329 true = CONST_DOUBLE_FROM_REAL_VALUE (FLOAT_STORE_FLAG_VALUE,
5331 false = CONST0_RTX (mode);
5353 new = simplify_relational_operation (code, mode_arg0,
5354 const_arg0 ? const_arg0 : folded_arg0,
5355 const_arg1 ? const_arg1 : folded_arg1);
5356 #ifdef FLOAT_STORE_FLAG_VALUE
5357 if (new != 0 && GET_MODE_CLASS (mode) == MODE_FLOAT)
5358 new = ((new == const0_rtx) ? CONST0_RTX (mode)
5359 : CONST_DOUBLE_FROM_REAL_VALUE (FLOAT_STORE_FLAG_VALUE, mode));
5368 /* If the second operand is a LABEL_REF, see if the first is a MINUS
5369 with that LABEL_REF as its second operand. If so, the result is
5370 the first operand of that MINUS. This handles switches with an
5371 ADDR_DIFF_VEC table. */
5372 if (const_arg1 && GET_CODE (const_arg1) == LABEL_REF)
5375 = GET_CODE (folded_arg0) == MINUS ? folded_arg0
5376 : lookup_as_function (folded_arg0, MINUS);
5378 if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF
5379 && XEXP (XEXP (y, 1), 0) == XEXP (const_arg1, 0))
5382 /* Now try for a CONST of a MINUS like the above. */
5383 if ((y = (GET_CODE (folded_arg0) == CONST ? folded_arg0
5384 : lookup_as_function (folded_arg0, CONST))) != 0
5385 && GET_CODE (XEXP (y, 0)) == MINUS
5386 && GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF
5387 && XEXP (XEXP (XEXP (y, 0),1), 0) == XEXP (const_arg1, 0))
5388 return XEXP (XEXP (y, 0), 0);
5391 /* Likewise if the operands are in the other order. */
5392 if (const_arg0 && GET_CODE (const_arg0) == LABEL_REF)
5395 = GET_CODE (folded_arg1) == MINUS ? folded_arg1
5396 : lookup_as_function (folded_arg1, MINUS);
5398 if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF
5399 && XEXP (XEXP (y, 1), 0) == XEXP (const_arg0, 0))
5402 /* Now try for a CONST of a MINUS like the above. */
5403 if ((y = (GET_CODE (folded_arg1) == CONST ? folded_arg1
5404 : lookup_as_function (folded_arg1, CONST))) != 0
5405 && GET_CODE (XEXP (y, 0)) == MINUS
5406 && GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF
5407 && XEXP (XEXP (XEXP (y, 0),1), 0) == XEXP (const_arg0, 0))
5408 return XEXP (XEXP (y, 0), 0);
5411 /* If second operand is a register equivalent to a negative
5412 CONST_INT, see if we can find a register equivalent to the
5413 positive constant. Make a MINUS if so. Don't do this for
5414 a negative constant since we might then alternate between
5415 chosing positive and negative constants. Having the positive
5416 constant previously-used is the more common case. */
5417 if (const_arg1 && GET_CODE (const_arg1) == CONST_INT
5418 && INTVAL (const_arg1) < 0 && GET_CODE (folded_arg1) == REG)
5420 rtx new_const = GEN_INT (- INTVAL (const_arg1));
5422 = lookup (new_const, safe_hash (new_const, mode) % NBUCKETS,
5426 for (p = p->first_same_value; p; p = p->next_same_value)
5427 if (GET_CODE (p->exp) == REG)
5428 return cse_gen_binary (MINUS, mode, folded_arg0,
5429 canon_reg (p->exp, NULL_RTX));
5434 /* If we have (MINUS Y C), see if Y is known to be (PLUS Z C2).
5435 If so, produce (PLUS Z C2-C). */
5436 if (const_arg1 != 0 && GET_CODE (const_arg1) == CONST_INT)
5438 rtx y = lookup_as_function (XEXP (x, 0), PLUS);
5439 if (y && GET_CODE (XEXP (y, 1)) == CONST_INT)
5440 return fold_rtx (plus_constant (copy_rtx (y),
5441 -INTVAL (const_arg1)),
5445 /* ... fall through ... */
5448 case SMIN: case SMAX: case UMIN: case UMAX:
5449 case IOR: case AND: case XOR:
5450 case MULT: case DIV: case UDIV:
5451 case ASHIFT: case LSHIFTRT: case ASHIFTRT:
5452 /* If we have (<op> <reg> <const_int>) for an associative OP and REG
5453 is known to be of similar form, we may be able to replace the
5454 operation with a combined operation. This may eliminate the
5455 intermediate operation if every use is simplified in this way.
5456 Note that the similar optimization done by combine.c only works
5457 if the intermediate operation's result has only one reference. */
5459 if (GET_CODE (folded_arg0) == REG
5460 && const_arg1 && GET_CODE (const_arg1) == CONST_INT)
5463 = (code == ASHIFT || code == ASHIFTRT || code == LSHIFTRT);
5464 rtx y = lookup_as_function (folded_arg0, code);
5466 enum rtx_code associate_code;
5470 || 0 == (inner_const
5471 = equiv_constant (fold_rtx (XEXP (y, 1), 0)))
5472 || GET_CODE (inner_const) != CONST_INT
5473 /* If we have compiled a statement like
5474 "if (x == (x & mask1))", and now are looking at
5475 "x & mask2", we will have a case where the first operand
5476 of Y is the same as our first operand. Unless we detect
5477 this case, an infinite loop will result. */
5478 || XEXP (y, 0) == folded_arg0)
5481 /* Don't associate these operations if they are a PLUS with the
5482 same constant and it is a power of two. These might be doable
5483 with a pre- or post-increment. Similarly for two subtracts of
5484 identical powers of two with post decrement. */
5486 if (code == PLUS && INTVAL (const_arg1) == INTVAL (inner_const)
5488 #if defined(HAVE_PRE_INCREMENT) || defined(HAVE_POST_INCREMENT)
5489 || exact_log2 (INTVAL (const_arg1)) >= 0
5491 #if defined(HAVE_PRE_DECREMENT) || defined(HAVE_POST_DECREMENT)
5492 || exact_log2 (- INTVAL (const_arg1)) >= 0
5497 /* Compute the code used to compose the constants. For example,
5498 A/C1/C2 is A/(C1 * C2), so if CODE == DIV, we want MULT. */
5501 = (code == MULT || code == DIV || code == UDIV ? MULT
5502 : is_shift || code == PLUS || code == MINUS ? PLUS : code);
5504 new_const = simplify_binary_operation (associate_code, mode,
5505 const_arg1, inner_const);
5510 /* If we are associating shift operations, don't let this
5511 produce a shift of the size of the object or larger.
5512 This could occur when we follow a sign-extend by a right
5513 shift on a machine that does a sign-extend as a pair
5516 if (is_shift && GET_CODE (new_const) == CONST_INT
5517 && INTVAL (new_const) >= GET_MODE_BITSIZE (mode))
5519 /* As an exception, we can turn an ASHIFTRT of this
5520 form into a shift of the number of bits - 1. */
5521 if (code == ASHIFTRT)
5522 new_const = GEN_INT (GET_MODE_BITSIZE (mode) - 1);
5527 y = copy_rtx (XEXP (y, 0));
5529 /* If Y contains our first operand (the most common way this
5530 can happen is if Y is a MEM), we would do into an infinite
5531 loop if we tried to fold it. So don't in that case. */
5533 if (! reg_mentioned_p (folded_arg0, y))
5534 y = fold_rtx (y, insn);
5536 return cse_gen_binary (code, mode, y, new_const);
5540 new = simplify_binary_operation (code, mode,
5541 const_arg0 ? const_arg0 : folded_arg0,
5542 const_arg1 ? const_arg1 : folded_arg1);
5546 /* (lo_sum (high X) X) is simply X. */
5547 if (code == LO_SUM && const_arg0 != 0
5548 && GET_CODE (const_arg0) == HIGH
5549 && rtx_equal_p (XEXP (const_arg0, 0), const_arg1))
5555 new = simplify_ternary_operation (code, mode, mode_arg0,
5556 const_arg0 ? const_arg0 : folded_arg0,
5557 const_arg1 ? const_arg1 : folded_arg1,
5558 const_arg2 ? const_arg2 : XEXP (x, 2));
5562 return new ? new : x;
5565 /* Return a constant value currently equivalent to X.
5566 Return 0 if we don't know one. */
5572 if (GET_CODE (x) == REG
5573 && REGNO_QTY_VALID_P (REGNO (x))
5574 && qty_const[reg_qty[REGNO (x)]])
5575 x = gen_lowpart_if_possible (GET_MODE (x), qty_const[reg_qty[REGNO (x)]]);
5577 if (x != 0 && CONSTANT_P (x))
5580 /* If X is a MEM, try to fold it outside the context of any insn to see if
5581 it might be equivalent to a constant. That handles the case where it
5582 is a constant-pool reference. Then try to look it up in the hash table
5583 in case it is something whose value we have seen before. */
5585 if (GET_CODE (x) == MEM)
5587 struct table_elt *elt;
5589 x = fold_rtx (x, NULL_RTX);
5593 elt = lookup (x, safe_hash (x, GET_MODE (x)) % NBUCKETS, GET_MODE (x));
5597 for (elt = elt->first_same_value; elt; elt = elt->next_same_value)
5598 if (elt->is_const && CONSTANT_P (elt->exp))
5605 /* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a fixed-point
5606 number, return an rtx (MEM, SUBREG, or CONST_INT) that refers to the
5607 least-significant part of X.
5608 MODE specifies how big a part of X to return.
5610 If the requested operation cannot be done, 0 is returned.
5612 This is similar to gen_lowpart in emit-rtl.c. */
5615 gen_lowpart_if_possible (mode, x)
5616 enum machine_mode mode;
5619 rtx result = gen_lowpart_common (mode, x);
5623 else if (GET_CODE (x) == MEM)
5625 /* This is the only other case we handle. */
5626 register int offset = 0;
5629 if (WORDS_BIG_ENDIAN)
5630 offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
5631 - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
5632 if (BYTES_BIG_ENDIAN)
5633 /* Adjust the address so that the address-after-the-data is
5635 offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
5636 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
5637 new = gen_rtx (MEM, mode, plus_constant (XEXP (x, 0), offset));
5638 if (! memory_address_p (mode, XEXP (new, 0)))
5640 MEM_VOLATILE_P (new) = MEM_VOLATILE_P (x);
5641 RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (x);
5642 MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (x);
5649 /* Given INSN, a jump insn, TAKEN indicates if we are following the "taken"
5650 branch. It will be zero if not.
5652 In certain cases, this can cause us to add an equivalence. For example,
5653 if we are following the taken case of
5655 we can add the fact that `i' and '2' are now equivalent.
5657 In any case, we can record that this comparison was passed. If the same
5658 comparison is seen later, we will know its value. */
5661 record_jump_equiv (insn, taken)
5665 int cond_known_true;
5667 enum machine_mode mode, mode0, mode1;
5668 int reversed_nonequality = 0;
5671 /* Ensure this is the right kind of insn. */
5672 if (! condjump_p (insn) || simplejump_p (insn))
5675 /* See if this jump condition is known true or false. */
5677 cond_known_true = (XEXP (SET_SRC (PATTERN (insn)), 2) == pc_rtx);
5679 cond_known_true = (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx);
5681 /* Get the type of comparison being done and the operands being compared.
5682 If we had to reverse a non-equality condition, record that fact so we
5683 know that it isn't valid for floating-point. */
5684 code = GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 0));
5685 op0 = fold_rtx (XEXP (XEXP (SET_SRC (PATTERN (insn)), 0), 0), insn);
5686 op1 = fold_rtx (XEXP (XEXP (SET_SRC (PATTERN (insn)), 0), 1), insn);
5688 code = find_comparison_args (code, &op0, &op1, &mode0, &mode1);
5689 if (! cond_known_true)
5691 reversed_nonequality = (code != EQ && code != NE);
5692 code = reverse_condition (code);
5695 /* The mode is the mode of the non-constant. */
5697 if (mode1 != VOIDmode)
5700 record_jump_cond (code, mode, op0, op1, reversed_nonequality);
5703 /* We know that comparison CODE applied to OP0 and OP1 in MODE is true.
5704 REVERSED_NONEQUALITY is nonzero if CODE had to be swapped.
5705 Make any useful entries we can with that information. Called from
5706 above function and called recursively. */
5709 record_jump_cond (code, mode, op0, op1, reversed_nonequality)
5711 enum machine_mode mode;
5713 int reversed_nonequality;
5715 unsigned op0_hash, op1_hash;
5716 int op0_in_memory, op0_in_struct, op1_in_memory, op1_in_struct;
5717 struct table_elt *op0_elt, *op1_elt;
5719 /* If OP0 and OP1 are known equal, and either is a paradoxical SUBREG,
5720 we know that they are also equal in the smaller mode (this is also
5721 true for all smaller modes whether or not there is a SUBREG, but
5722 is not worth testing for with no SUBREG. */
5724 /* Note that GET_MODE (op0) may not equal MODE. */
5725 if (code == EQ && GET_CODE (op0) == SUBREG
5726 && (GET_MODE_SIZE (GET_MODE (op0))
5727 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))
5729 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
5730 rtx tem = gen_lowpart_if_possible (inner_mode, op1);
5732 record_jump_cond (code, mode, SUBREG_REG (op0),
5733 tem ? tem : gen_rtx (SUBREG, inner_mode, op1, 0),
5734 reversed_nonequality);
5737 if (code == EQ && GET_CODE (op1) == SUBREG
5738 && (GET_MODE_SIZE (GET_MODE (op1))
5739 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op1)))))
5741 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1));
5742 rtx tem = gen_lowpart_if_possible (inner_mode, op0);
5744 record_jump_cond (code, mode, SUBREG_REG (op1),
5745 tem ? tem : gen_rtx (SUBREG, inner_mode, op0, 0),
5746 reversed_nonequality);
5749 /* Similarly, if this is an NE comparison, and either is a SUBREG
5750 making a smaller mode, we know the whole thing is also NE. */
5752 /* Note that GET_MODE (op0) may not equal MODE;
5753 if we test MODE instead, we can get an infinite recursion
5754 alternating between two modes each wider than MODE. */
5756 if (code == NE && GET_CODE (op0) == SUBREG
5757 && subreg_lowpart_p (op0)
5758 && (GET_MODE_SIZE (GET_MODE (op0))
5759 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))
5761 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
5762 rtx tem = gen_lowpart_if_possible (inner_mode, op1);
5764 record_jump_cond (code, mode, SUBREG_REG (op0),
5765 tem ? tem : gen_rtx (SUBREG, inner_mode, op1, 0),
5766 reversed_nonequality);
5769 if (code == NE && GET_CODE (op1) == SUBREG
5770 && subreg_lowpart_p (op1)
5771 && (GET_MODE_SIZE (GET_MODE (op1))
5772 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (op1)))))
5774 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1));
5775 rtx tem = gen_lowpart_if_possible (inner_mode, op0);
5777 record_jump_cond (code, mode, SUBREG_REG (op1),
5778 tem ? tem : gen_rtx (SUBREG, inner_mode, op0, 0),
5779 reversed_nonequality);
5782 /* Hash both operands. */
5785 hash_arg_in_memory = 0;
5786 hash_arg_in_struct = 0;
5787 op0_hash = HASH (op0, mode);
5788 op0_in_memory = hash_arg_in_memory;
5789 op0_in_struct = hash_arg_in_struct;
5795 hash_arg_in_memory = 0;
5796 hash_arg_in_struct = 0;
5797 op1_hash = HASH (op1, mode);
5798 op1_in_memory = hash_arg_in_memory;
5799 op1_in_struct = hash_arg_in_struct;
5804 /* Look up both operands. */
5805 op0_elt = lookup (op0, op0_hash, mode);
5806 op1_elt = lookup (op1, op1_hash, mode);
5808 /* If both operands are already equivalent or if they are not in the
5809 table but are identical, do nothing. */
5810 if ((op0_elt != 0 && op1_elt != 0
5811 && op0_elt->first_same_value == op1_elt->first_same_value)
5812 || op0 == op1 || rtx_equal_p (op0, op1))
5815 /* If we aren't setting two things equal all we can do is save this
5816 comparison. Similarly if this is floating-point. In the latter
5817 case, OP1 might be zero and both -0.0 and 0.0 are equal to it.
5818 If we record the equality, we might inadvertently delete code
5819 whose intent was to change -0 to +0. */
5821 if (code != EQ || FLOAT_MODE_P (GET_MODE (op0)))
5823 /* If we reversed a floating-point comparison, if OP0 is not a
5824 register, or if OP1 is neither a register or constant, we can't
5827 if (GET_CODE (op1) != REG)
5828 op1 = equiv_constant (op1);
5830 if ((reversed_nonequality && FLOAT_MODE_P (mode))
5831 || GET_CODE (op0) != REG || op1 == 0)
5834 /* Put OP0 in the hash table if it isn't already. This gives it a
5835 new quantity number. */
5838 if (insert_regs (op0, NULL_PTR, 0))
5840 rehash_using_reg (op0);
5841 op0_hash = HASH (op0, mode);
5843 /* If OP0 is contained in OP1, this changes its hash code
5844 as well. Faster to rehash than to check, except
5845 for the simple case of a constant. */
5846 if (! CONSTANT_P (op1))
5847 op1_hash = HASH (op1,mode);
5850 op0_elt = insert (op0, NULL_PTR, op0_hash, mode);
5851 op0_elt->in_memory = op0_in_memory;
5852 op0_elt->in_struct = op0_in_struct;
5855 qty_comparison_code[reg_qty[REGNO (op0)]] = code;
5856 if (GET_CODE (op1) == REG)
5858 /* Look it up again--in case op0 and op1 are the same. */
5859 op1_elt = lookup (op1, op1_hash, mode);
5861 /* Put OP1 in the hash table so it gets a new quantity number. */
5864 if (insert_regs (op1, NULL_PTR, 0))
5866 rehash_using_reg (op1);
5867 op1_hash = HASH (op1, mode);
5870 op1_elt = insert (op1, NULL_PTR, op1_hash, mode);
5871 op1_elt->in_memory = op1_in_memory;
5872 op1_elt->in_struct = op1_in_struct;
5875 qty_comparison_qty[reg_qty[REGNO (op0)]] = reg_qty[REGNO (op1)];
5876 qty_comparison_const[reg_qty[REGNO (op0)]] = 0;
5880 qty_comparison_qty[reg_qty[REGNO (op0)]] = -1;
5881 qty_comparison_const[reg_qty[REGNO (op0)]] = op1;
5887 /* If either side is still missing an equivalence, make it now,
5888 then merge the equivalences. */
5892 if (insert_regs (op0, NULL_PTR, 0))
5894 rehash_using_reg (op0);
5895 op0_hash = HASH (op0, mode);
5898 op0_elt = insert (op0, NULL_PTR, op0_hash, mode);
5899 op0_elt->in_memory = op0_in_memory;
5900 op0_elt->in_struct = op0_in_struct;
5905 if (insert_regs (op1, NULL_PTR, 0))
5907 rehash_using_reg (op1);
5908 op1_hash = HASH (op1, mode);
5911 op1_elt = insert (op1, NULL_PTR, op1_hash, mode);
5912 op1_elt->in_memory = op1_in_memory;
5913 op1_elt->in_struct = op1_in_struct;
5916 merge_equiv_classes (op0_elt, op1_elt);
5917 last_jump_equiv_class = op0_elt;
5920 /* CSE processing for one instruction.
5921 First simplify sources and addresses of all assignments
5922 in the instruction, using previously-computed equivalents values.
5923 Then install the new sources and destinations in the table
5924 of available values.
5926 If IN_LIBCALL_BLOCK is nonzero, don't record any equivalence made in
5929 /* Data on one SET contained in the instruction. */
5933 /* The SET rtx itself. */
5935 /* The SET_SRC of the rtx (the original value, if it is changing). */
5937 /* The hash-table element for the SET_SRC of the SET. */
5938 struct table_elt *src_elt;
5939 /* Hash value for the SET_SRC. */
5941 /* Hash value for the SET_DEST. */
5943 /* The SET_DEST, with SUBREG, etc., stripped. */
5945 /* Place where the pointer to the INNER_DEST was found. */
5946 rtx *inner_dest_loc;
5947 /* Nonzero if the SET_SRC is in memory. */
5949 /* Nonzero if the SET_SRC is in a structure. */
5951 /* Nonzero if the SET_SRC contains something
5952 whose value cannot be predicted and understood. */
5954 /* Original machine mode, in case it becomes a CONST_INT. */
5955 enum machine_mode mode;
5956 /* A constant equivalent for SET_SRC, if any. */
5958 /* Hash value of constant equivalent for SET_SRC. */
5959 unsigned src_const_hash;
5960 /* Table entry for constant equivalent for SET_SRC, if any. */
5961 struct table_elt *src_const_elt;
5965 cse_insn (insn, in_libcall_block)
5967 int in_libcall_block;
5969 register rtx x = PATTERN (insn);
5972 register int n_sets = 0;
5974 /* Records what this insn does to set CC0. */
5975 rtx this_insn_cc0 = 0;
5976 enum machine_mode this_insn_cc0_mode;
5977 struct write_data writes_memory;
5978 static struct write_data init = {0, 0, 0, 0};
5981 struct table_elt *src_eqv_elt = 0;
5982 int src_eqv_volatile;
5983 int src_eqv_in_memory;
5984 int src_eqv_in_struct;
5985 unsigned src_eqv_hash;
5990 writes_memory = init;
5992 /* Find all the SETs and CLOBBERs in this instruction.
5993 Record all the SETs in the array `set' and count them.
5994 Also determine whether there is a CLOBBER that invalidates
5995 all memory references, or all references at varying addresses. */
5997 if (GET_CODE (insn) == CALL_INSN)
5999 for (tem = CALL_INSN_FUNCTION_USAGE (insn); tem; tem = XEXP (tem, 1))
6000 if (GET_CODE (XEXP (tem, 0)) == CLOBBER)
6001 invalidate (SET_DEST (XEXP (tem, 0)), VOIDmode);
6004 if (GET_CODE (x) == SET)
6006 sets = (struct set *) alloca (sizeof (struct set));
6009 /* Ignore SETs that are unconditional jumps.
6010 They never need cse processing, so this does not hurt.
6011 The reason is not efficiency but rather
6012 so that we can test at the end for instructions
6013 that have been simplified to unconditional jumps
6014 and not be misled by unchanged instructions
6015 that were unconditional jumps to begin with. */
6016 if (SET_DEST (x) == pc_rtx
6017 && GET_CODE (SET_SRC (x)) == LABEL_REF)
6020 /* Don't count call-insns, (set (reg 0) (call ...)), as a set.
6021 The hard function value register is used only once, to copy to
6022 someplace else, so it isn't worth cse'ing (and on 80386 is unsafe)!
6023 Ensure we invalidate the destination register. On the 80386 no
6024 other code would invalidate it since it is a fixed_reg.
6025 We need not check the return of apply_change_group; see canon_reg. */
6027 else if (GET_CODE (SET_SRC (x)) == CALL)
6029 canon_reg (SET_SRC (x), insn);
6030 apply_change_group ();
6031 fold_rtx (SET_SRC (x), insn);
6032 invalidate (SET_DEST (x), VOIDmode);
6037 else if (GET_CODE (x) == PARALLEL)
6039 register int lim = XVECLEN (x, 0);
6041 sets = (struct set *) alloca (lim * sizeof (struct set));
6043 /* Find all regs explicitly clobbered in this insn,
6044 and ensure they are not replaced with any other regs
6045 elsewhere in this insn.
6046 When a reg that is clobbered is also used for input,
6047 we should presume that that is for a reason,
6048 and we should not substitute some other register
6049 which is not supposed to be clobbered.
6050 Therefore, this loop cannot be merged into the one below
6051 because a CALL may precede a CLOBBER and refer to the
6052 value clobbered. We must not let a canonicalization do
6053 anything in that case. */
6054 for (i = 0; i < lim; i++)
6056 register rtx y = XVECEXP (x, 0, i);
6057 if (GET_CODE (y) == CLOBBER)
6059 rtx clobbered = XEXP (y, 0);
6061 if (GET_CODE (clobbered) == REG
6062 || GET_CODE (clobbered) == SUBREG)
6063 invalidate (clobbered, VOIDmode);
6064 else if (GET_CODE (clobbered) == STRICT_LOW_PART
6065 || GET_CODE (clobbered) == ZERO_EXTRACT)
6066 invalidate (XEXP (clobbered, 0), GET_MODE (clobbered));
6070 for (i = 0; i < lim; i++)
6072 register rtx y = XVECEXP (x, 0, i);
6073 if (GET_CODE (y) == SET)
6075 /* As above, we ignore unconditional jumps and call-insns and
6076 ignore the result of apply_change_group. */
6077 if (GET_CODE (SET_SRC (y)) == CALL)
6079 canon_reg (SET_SRC (y), insn);
6080 apply_change_group ();
6081 fold_rtx (SET_SRC (y), insn);
6082 invalidate (SET_DEST (y), VOIDmode);
6084 else if (SET_DEST (y) == pc_rtx
6085 && GET_CODE (SET_SRC (y)) == LABEL_REF)
6088 sets[n_sets++].rtl = y;
6090 else if (GET_CODE (y) == CLOBBER)
6092 /* If we clobber memory, take note of that,
6093 and canon the address.
6094 This does nothing when a register is clobbered
6095 because we have already invalidated the reg. */
6096 if (GET_CODE (XEXP (y, 0)) == MEM)
6098 canon_reg (XEXP (y, 0), NULL_RTX);
6099 note_mem_written (XEXP (y, 0), &writes_memory);
6102 else if (GET_CODE (y) == USE
6103 && ! (GET_CODE (XEXP (y, 0)) == REG
6104 && REGNO (XEXP (y, 0)) < FIRST_PSEUDO_REGISTER))
6105 canon_reg (y, NULL_RTX);
6106 else if (GET_CODE (y) == CALL)
6108 /* The result of apply_change_group can be ignored; see
6110 canon_reg (y, insn);
6111 apply_change_group ();
6116 else if (GET_CODE (x) == CLOBBER)
6118 if (GET_CODE (XEXP (x, 0)) == MEM)
6120 canon_reg (XEXP (x, 0), NULL_RTX);
6121 note_mem_written (XEXP (x, 0), &writes_memory);
6125 /* Canonicalize a USE of a pseudo register or memory location. */
6126 else if (GET_CODE (x) == USE
6127 && ! (GET_CODE (XEXP (x, 0)) == REG
6128 && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER))
6129 canon_reg (XEXP (x, 0), NULL_RTX);
6130 else if (GET_CODE (x) == CALL)
6132 /* The result of apply_change_group can be ignored; see canon_reg. */
6133 canon_reg (x, insn);
6134 apply_change_group ();
6138 /* Store the equivalent value in SRC_EQV, if different, or if the DEST
6139 is a STRICT_LOW_PART. The latter condition is necessary because SRC_EQV
6140 is handled specially for this case, and if it isn't set, then there will
6141 be no equivalence for the destinatation. */
6142 if (n_sets == 1 && REG_NOTES (insn) != 0
6143 && (tem = find_reg_note (insn, REG_EQUAL, NULL_RTX)) != 0
6144 && (! rtx_equal_p (XEXP (tem, 0), SET_SRC (sets[0].rtl))
6145 || GET_CODE (SET_DEST (sets[0].rtl)) == STRICT_LOW_PART))
6146 src_eqv = canon_reg (XEXP (tem, 0), NULL_RTX);
6148 /* Canonicalize sources and addresses of destinations.
6149 We do this in a separate pass to avoid problems when a MATCH_DUP is
6150 present in the insn pattern. In that case, we want to ensure that
6151 we don't break the duplicate nature of the pattern. So we will replace
6152 both operands at the same time. Otherwise, we would fail to find an
6153 equivalent substitution in the loop calling validate_change below.
6155 We used to suppress canonicalization of DEST if it appears in SRC,
6156 but we don't do this any more. */
6158 for (i = 0; i < n_sets; i++)
6160 rtx dest = SET_DEST (sets[i].rtl);
6161 rtx src = SET_SRC (sets[i].rtl);
6162 rtx new = canon_reg (src, insn);
6164 if ((GET_CODE (new) == REG && GET_CODE (src) == REG
6165 && ((REGNO (new) < FIRST_PSEUDO_REGISTER)
6166 != (REGNO (src) < FIRST_PSEUDO_REGISTER)))
6167 || insn_n_dups[recog_memoized (insn)] > 0)
6168 validate_change (insn, &SET_SRC (sets[i].rtl), new, 1);
6170 SET_SRC (sets[i].rtl) = new;
6172 if (GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == SIGN_EXTRACT)
6174 validate_change (insn, &XEXP (dest, 1),
6175 canon_reg (XEXP (dest, 1), insn), 1);
6176 validate_change (insn, &XEXP (dest, 2),
6177 canon_reg (XEXP (dest, 2), insn), 1);
6180 while (GET_CODE (dest) == SUBREG || GET_CODE (dest) == STRICT_LOW_PART
6181 || GET_CODE (dest) == ZERO_EXTRACT
6182 || GET_CODE (dest) == SIGN_EXTRACT)
6183 dest = XEXP (dest, 0);
6185 if (GET_CODE (dest) == MEM)
6186 canon_reg (dest, insn);
6189 /* Now that we have done all the replacements, we can apply the change
6190 group and see if they all work. Note that this will cause some
6191 canonicalizations that would have worked individually not to be applied
6192 because some other canonicalization didn't work, but this should not
6195 The result of apply_change_group can be ignored; see canon_reg. */
6197 apply_change_group ();
6199 /* Set sets[i].src_elt to the class each source belongs to.
6200 Detect assignments from or to volatile things
6201 and set set[i] to zero so they will be ignored
6202 in the rest of this function.
6204 Nothing in this loop changes the hash table or the register chains. */
6206 for (i = 0; i < n_sets; i++)
6208 register rtx src, dest;
6209 register rtx src_folded;
6210 register struct table_elt *elt = 0, *p;
6211 enum machine_mode mode;
6214 rtx src_related = 0;
6215 struct table_elt *src_const_elt = 0;
6216 int src_cost = 10000, src_eqv_cost = 10000, src_folded_cost = 10000;
6217 int src_related_cost = 10000, src_elt_cost = 10000;
6218 /* Set non-zero if we need to call force_const_mem on with the
6219 contents of src_folded before using it. */
6220 int src_folded_force_flag = 0;
6222 dest = SET_DEST (sets[i].rtl);
6223 src = SET_SRC (sets[i].rtl);
6225 /* If SRC is a constant that has no machine mode,
6226 hash it with the destination's machine mode.
6227 This way we can keep different modes separate. */
6229 mode = GET_MODE (src) == VOIDmode ? GET_MODE (dest) : GET_MODE (src);
6230 sets[i].mode = mode;
6234 enum machine_mode eqvmode = mode;
6235 if (GET_CODE (dest) == STRICT_LOW_PART)
6236 eqvmode = GET_MODE (SUBREG_REG (XEXP (dest, 0)));
6238 hash_arg_in_memory = 0;
6239 hash_arg_in_struct = 0;
6240 src_eqv = fold_rtx (src_eqv, insn);
6241 src_eqv_hash = HASH (src_eqv, eqvmode);
6243 /* Find the equivalence class for the equivalent expression. */
6246 src_eqv_elt = lookup (src_eqv, src_eqv_hash, eqvmode);
6248 src_eqv_volatile = do_not_record;
6249 src_eqv_in_memory = hash_arg_in_memory;
6250 src_eqv_in_struct = hash_arg_in_struct;
6253 /* If this is a STRICT_LOW_PART assignment, src_eqv corresponds to the
6254 value of the INNER register, not the destination. So it is not
6255 a legal substitution for the source. But save it for later. */
6256 if (GET_CODE (dest) == STRICT_LOW_PART)
6259 src_eqv_here = src_eqv;
6261 /* Simplify and foldable subexpressions in SRC. Then get the fully-
6262 simplified result, which may not necessarily be valid. */
6263 src_folded = fold_rtx (src, insn);
6265 /* If storing a constant in a bitfield, pre-truncate the constant
6266 so we will be able to record it later. */
6267 if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT
6268 || GET_CODE (SET_DEST (sets[i].rtl)) == SIGN_EXTRACT)
6270 rtx width = XEXP (SET_DEST (sets[i].rtl), 1);
6272 if (GET_CODE (src) == CONST_INT
6273 && GET_CODE (width) == CONST_INT
6274 && INTVAL (width) < HOST_BITS_PER_WIDE_INT
6275 && (INTVAL (src) & ((HOST_WIDE_INT) (-1) << INTVAL (width))))
6277 = GEN_INT (INTVAL (src) & (((HOST_WIDE_INT) 1
6278 << INTVAL (width)) - 1));
6281 /* Compute SRC's hash code, and also notice if it
6282 should not be recorded at all. In that case,
6283 prevent any further processing of this assignment. */
6285 hash_arg_in_memory = 0;
6286 hash_arg_in_struct = 0;
6289 sets[i].src_hash = HASH (src, mode);
6290 sets[i].src_volatile = do_not_record;
6291 sets[i].src_in_memory = hash_arg_in_memory;
6292 sets[i].src_in_struct = hash_arg_in_struct;
6295 /* It is no longer clear why we used to do this, but it doesn't
6296 appear to still be needed. So let's try without it since this
6297 code hurts cse'ing widened ops. */
6298 /* If source is a perverse subreg (such as QI treated as an SI),
6299 treat it as volatile. It may do the work of an SI in one context
6300 where the extra bits are not being used, but cannot replace an SI
6302 if (GET_CODE (src) == SUBREG
6303 && (GET_MODE_SIZE (GET_MODE (src))
6304 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))))
6305 sets[i].src_volatile = 1;
6308 /* Locate all possible equivalent forms for SRC. Try to replace
6309 SRC in the insn with each cheaper equivalent.
6311 We have the following types of equivalents: SRC itself, a folded
6312 version, a value given in a REG_EQUAL note, or a value related
6315 Each of these equivalents may be part of an additional class
6316 of equivalents (if more than one is in the table, they must be in
6317 the same class; we check for this).
6319 If the source is volatile, we don't do any table lookups.
6321 We note any constant equivalent for possible later use in a
6324 if (!sets[i].src_volatile)
6325 elt = lookup (src, sets[i].src_hash, mode);
6327 sets[i].src_elt = elt;
6329 if (elt && src_eqv_here && src_eqv_elt)
6331 if (elt->first_same_value != src_eqv_elt->first_same_value)
6333 /* The REG_EQUAL is indicating that two formerly distinct
6334 classes are now equivalent. So merge them. */
6335 merge_equiv_classes (elt, src_eqv_elt);
6336 src_eqv_hash = HASH (src_eqv, elt->mode);
6337 src_eqv_elt = lookup (src_eqv, src_eqv_hash, elt->mode);
6343 else if (src_eqv_elt)
6346 /* Try to find a constant somewhere and record it in `src_const'.
6347 Record its table element, if any, in `src_const_elt'. Look in
6348 any known equivalences first. (If the constant is not in the
6349 table, also set `sets[i].src_const_hash'). */
6351 for (p = elt->first_same_value; p; p = p->next_same_value)
6355 src_const_elt = elt;
6360 && (CONSTANT_P (src_folded)
6361 /* Consider (minus (label_ref L1) (label_ref L2)) as
6362 "constant" here so we will record it. This allows us
6363 to fold switch statements when an ADDR_DIFF_VEC is used. */
6364 || (GET_CODE (src_folded) == MINUS
6365 && GET_CODE (XEXP (src_folded, 0)) == LABEL_REF
6366 && GET_CODE (XEXP (src_folded, 1)) == LABEL_REF)))
6367 src_const = src_folded, src_const_elt = elt;
6368 else if (src_const == 0 && src_eqv_here && CONSTANT_P (src_eqv_here))
6369 src_const = src_eqv_here, src_const_elt = src_eqv_elt;
6371 /* If we don't know if the constant is in the table, get its
6372 hash code and look it up. */
6373 if (src_const && src_const_elt == 0)
6375 sets[i].src_const_hash = HASH (src_const, mode);
6376 src_const_elt = lookup (src_const, sets[i].src_const_hash, mode);
6379 sets[i].src_const = src_const;
6380 sets[i].src_const_elt = src_const_elt;
6382 /* If the constant and our source are both in the table, mark them as
6383 equivalent. Otherwise, if a constant is in the table but the source
6384 isn't, set ELT to it. */
6385 if (src_const_elt && elt
6386 && src_const_elt->first_same_value != elt->first_same_value)
6387 merge_equiv_classes (elt, src_const_elt);
6388 else if (src_const_elt && elt == 0)
6389 elt = src_const_elt;
6391 /* See if there is a register linearly related to a constant
6392 equivalent of SRC. */
6394 && (GET_CODE (src_const) == CONST
6395 || (src_const_elt && src_const_elt->related_value != 0)))
6397 src_related = use_related_value (src_const, src_const_elt);
6400 struct table_elt *src_related_elt
6401 = lookup (src_related, HASH (src_related, mode), mode);
6402 if (src_related_elt && elt)
6404 if (elt->first_same_value
6405 != src_related_elt->first_same_value)
6406 /* This can occur when we previously saw a CONST
6407 involving a SYMBOL_REF and then see the SYMBOL_REF
6408 twice. Merge the involved classes. */
6409 merge_equiv_classes (elt, src_related_elt);
6412 src_related_elt = 0;
6414 else if (src_related_elt && elt == 0)
6415 elt = src_related_elt;
6419 /* See if we have a CONST_INT that is already in a register in a
6422 if (src_const && src_related == 0 && GET_CODE (src_const) == CONST_INT
6423 && GET_MODE_CLASS (mode) == MODE_INT
6424 && GET_MODE_BITSIZE (mode) < BITS_PER_WORD)
6426 enum machine_mode wider_mode;
6428 for (wider_mode = GET_MODE_WIDER_MODE (mode);
6429 GET_MODE_BITSIZE (wider_mode) <= BITS_PER_WORD
6430 && src_related == 0;
6431 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
6433 struct table_elt *const_elt
6434 = lookup (src_const, HASH (src_const, wider_mode), wider_mode);
6439 for (const_elt = const_elt->first_same_value;
6440 const_elt; const_elt = const_elt->next_same_value)
6441 if (GET_CODE (const_elt->exp) == REG)
6443 src_related = gen_lowpart_if_possible (mode,
6450 /* Another possibility is that we have an AND with a constant in
6451 a mode narrower than a word. If so, it might have been generated
6452 as part of an "if" which would narrow the AND. If we already
6453 have done the AND in a wider mode, we can use a SUBREG of that
6456 if (flag_expensive_optimizations && ! src_related
6457 && GET_CODE (src) == AND && GET_CODE (XEXP (src, 1)) == CONST_INT
6458 && GET_MODE_SIZE (mode) < UNITS_PER_WORD)
6460 enum machine_mode tmode;
6461 rtx new_and = gen_rtx (AND, VOIDmode, NULL_RTX, XEXP (src, 1));
6463 for (tmode = GET_MODE_WIDER_MODE (mode);
6464 GET_MODE_SIZE (tmode) <= UNITS_PER_WORD;
6465 tmode = GET_MODE_WIDER_MODE (tmode))
6467 rtx inner = gen_lowpart_if_possible (tmode, XEXP (src, 0));
6468 struct table_elt *larger_elt;
6472 PUT_MODE (new_and, tmode);
6473 XEXP (new_and, 0) = inner;
6474 larger_elt = lookup (new_and, HASH (new_and, tmode), tmode);
6475 if (larger_elt == 0)
6478 for (larger_elt = larger_elt->first_same_value;
6479 larger_elt; larger_elt = larger_elt->next_same_value)
6480 if (GET_CODE (larger_elt->exp) == REG)
6483 = gen_lowpart_if_possible (mode, larger_elt->exp);
6493 #ifdef LOAD_EXTEND_OP
6494 /* See if a MEM has already been loaded with a widening operation;
6495 if it has, we can use a subreg of that. Many CISC machines
6496 also have such operations, but this is only likely to be
6497 beneficial these machines. */
6499 if (flag_expensive_optimizations && src_related == 0
6500 && (GET_MODE_SIZE (mode) < UNITS_PER_WORD)
6501 && GET_MODE_CLASS (mode) == MODE_INT
6502 && GET_CODE (src) == MEM && ! do_not_record
6503 && LOAD_EXTEND_OP (mode) != NIL)
6505 enum machine_mode tmode;
6507 /* Set what we are trying to extend and the operation it might
6508 have been extended with. */
6509 PUT_CODE (memory_extend_rtx, LOAD_EXTEND_OP (mode));
6510 XEXP (memory_extend_rtx, 0) = src;
6512 for (tmode = GET_MODE_WIDER_MODE (mode);
6513 GET_MODE_SIZE (tmode) <= UNITS_PER_WORD;
6514 tmode = GET_MODE_WIDER_MODE (tmode))
6516 struct table_elt *larger_elt;
6518 PUT_MODE (memory_extend_rtx, tmode);
6519 larger_elt = lookup (memory_extend_rtx,
6520 HASH (memory_extend_rtx, tmode), tmode);
6521 if (larger_elt == 0)
6524 for (larger_elt = larger_elt->first_same_value;
6525 larger_elt; larger_elt = larger_elt->next_same_value)
6526 if (GET_CODE (larger_elt->exp) == REG)
6528 src_related = gen_lowpart_if_possible (mode,
6537 #endif /* LOAD_EXTEND_OP */
6539 if (src == src_folded)
6542 /* At this point, ELT, if non-zero, points to a class of expressions
6543 equivalent to the source of this SET and SRC, SRC_EQV, SRC_FOLDED,
6544 and SRC_RELATED, if non-zero, each contain additional equivalent
6545 expressions. Prune these latter expressions by deleting expressions
6546 already in the equivalence class.
6548 Check for an equivalent identical to the destination. If found,
6549 this is the preferred equivalent since it will likely lead to
6550 elimination of the insn. Indicate this by placing it in
6553 if (elt) elt = elt->first_same_value;
6554 for (p = elt; p; p = p->next_same_value)
6556 enum rtx_code code = GET_CODE (p->exp);
6558 /* If the expression is not valid, ignore it. Then we do not
6559 have to check for validity below. In most cases, we can use
6560 `rtx_equal_p', since canonicalization has already been done. */
6561 if (code != REG && ! exp_equiv_p (p->exp, p->exp, 1, 0))
6564 if (src && GET_CODE (src) == code && rtx_equal_p (src, p->exp))
6566 else if (src_folded && GET_CODE (src_folded) == code
6567 && rtx_equal_p (src_folded, p->exp))
6569 else if (src_eqv_here && GET_CODE (src_eqv_here) == code
6570 && rtx_equal_p (src_eqv_here, p->exp))
6572 else if (src_related && GET_CODE (src_related) == code
6573 && rtx_equal_p (src_related, p->exp))
6576 /* This is the same as the destination of the insns, we want
6577 to prefer it. Copy it to src_related. The code below will
6578 then give it a negative cost. */
6579 if (GET_CODE (dest) == code && rtx_equal_p (p->exp, dest))
6584 /* Find the cheapest valid equivalent, trying all the available
6585 possibilities. Prefer items not in the hash table to ones
6586 that are when they are equal cost. Note that we can never
6587 worsen an insn as the current contents will also succeed.
6588 If we find an equivalent identical to the destination, use it as best,
6589 since this insn will probably be eliminated in that case. */
6592 if (rtx_equal_p (src, dest))
6595 src_cost = COST (src);
6600 if (rtx_equal_p (src_eqv_here, dest))
6603 src_eqv_cost = COST (src_eqv_here);
6608 if (rtx_equal_p (src_folded, dest))
6609 src_folded_cost = -1;
6611 src_folded_cost = COST (src_folded);
6616 if (rtx_equal_p (src_related, dest))
6617 src_related_cost = -1;
6619 src_related_cost = COST (src_related);
6622 /* If this was an indirect jump insn, a known label will really be
6623 cheaper even though it looks more expensive. */
6624 if (dest == pc_rtx && src_const && GET_CODE (src_const) == LABEL_REF)
6625 src_folded = src_const, src_folded_cost = -1;
6627 /* Terminate loop when replacement made. This must terminate since
6628 the current contents will be tested and will always be valid. */
6633 /* Skip invalid entries. */
6634 while (elt && GET_CODE (elt->exp) != REG
6635 && ! exp_equiv_p (elt->exp, elt->exp, 1, 0))
6636 elt = elt->next_same_value;
6638 if (elt) src_elt_cost = elt->cost;
6640 /* Find cheapest and skip it for the next time. For items
6641 of equal cost, use this order:
6642 src_folded, src, src_eqv, src_related and hash table entry. */
6643 if (src_folded_cost <= src_cost
6644 && src_folded_cost <= src_eqv_cost
6645 && src_folded_cost <= src_related_cost
6646 && src_folded_cost <= src_elt_cost)
6648 trial = src_folded, src_folded_cost = 10000;
6649 if (src_folded_force_flag)
6650 trial = force_const_mem (mode, trial);
6652 else if (src_cost <= src_eqv_cost
6653 && src_cost <= src_related_cost
6654 && src_cost <= src_elt_cost)
6655 trial = src, src_cost = 10000;
6656 else if (src_eqv_cost <= src_related_cost
6657 && src_eqv_cost <= src_elt_cost)
6658 trial = copy_rtx (src_eqv_here), src_eqv_cost = 10000;
6659 else if (src_related_cost <= src_elt_cost)
6660 trial = copy_rtx (src_related), src_related_cost = 10000;
6663 trial = copy_rtx (elt->exp);
6664 elt = elt->next_same_value;
6665 src_elt_cost = 10000;
6668 /* We don't normally have an insn matching (set (pc) (pc)), so
6669 check for this separately here. We will delete such an
6672 Tablejump insns contain a USE of the table, so simply replacing
6673 the operand with the constant won't match. This is simply an
6674 unconditional branch, however, and is therefore valid. Just
6675 insert the substitution here and we will delete and re-emit
6678 if (n_sets == 1 && dest == pc_rtx
6680 || (GET_CODE (trial) == LABEL_REF
6681 && ! condjump_p (insn))))
6683 /* If TRIAL is a label in front of a jump table, we are
6684 really falling through the switch (this is how casesi
6685 insns work), so we must branch around the table. */
6686 if (GET_CODE (trial) == CODE_LABEL
6687 && NEXT_INSN (trial) != 0
6688 && GET_CODE (NEXT_INSN (trial)) == JUMP_INSN
6689 && (GET_CODE (PATTERN (NEXT_INSN (trial))) == ADDR_DIFF_VEC
6690 || GET_CODE (PATTERN (NEXT_INSN (trial))) == ADDR_VEC))
6692 trial = gen_rtx (LABEL_REF, Pmode, get_label_after (trial));
6694 SET_SRC (sets[i].rtl) = trial;
6695 cse_jumps_altered = 1;
6699 /* Look for a substitution that makes a valid insn. */
6700 else if (validate_change (insn, &SET_SRC (sets[i].rtl), trial, 0))
6702 /* The result of apply_change_group can be ignored; see
6705 validate_change (insn, &SET_SRC (sets[i].rtl),
6706 canon_reg (SET_SRC (sets[i].rtl), insn),
6708 apply_change_group ();
6712 /* If we previously found constant pool entries for
6713 constants and this is a constant, try making a
6714 pool entry. Put it in src_folded unless we already have done
6715 this since that is where it likely came from. */
6717 else if (constant_pool_entries_cost
6718 && CONSTANT_P (trial)
6719 && ! (GET_CODE (trial) == CONST
6720 && GET_CODE (XEXP (trial, 0)) == TRUNCATE)
6722 || (GET_CODE (src_folded) != MEM
6723 && ! src_folded_force_flag))
6724 && GET_MODE_CLASS (mode) != MODE_CC)
6726 src_folded_force_flag = 1;
6728 src_folded_cost = constant_pool_entries_cost;
6732 src = SET_SRC (sets[i].rtl);
6734 /* In general, it is good to have a SET with SET_SRC == SET_DEST.
6735 However, there is an important exception: If both are registers
6736 that are not the head of their equivalence class, replace SET_SRC
6737 with the head of the class. If we do not do this, we will have
6738 both registers live over a portion of the basic block. This way,
6739 their lifetimes will likely abut instead of overlapping. */
6740 if (GET_CODE (dest) == REG
6741 && REGNO_QTY_VALID_P (REGNO (dest))
6742 && qty_mode[reg_qty[REGNO (dest)]] == GET_MODE (dest)
6743 && qty_first_reg[reg_qty[REGNO (dest)]] != REGNO (dest)
6744 && GET_CODE (src) == REG && REGNO (src) == REGNO (dest)
6745 /* Don't do this if the original insn had a hard reg as
6747 && (GET_CODE (sets[i].src) != REG
6748 || REGNO (sets[i].src) >= FIRST_PSEUDO_REGISTER))
6749 /* We can't call canon_reg here because it won't do anything if
6750 SRC is a hard register. */
6752 int first = qty_first_reg[reg_qty[REGNO (src)]];
6754 src = SET_SRC (sets[i].rtl)
6755 = first >= FIRST_PSEUDO_REGISTER ? regno_reg_rtx[first]
6756 : gen_rtx (REG, GET_MODE (src), first);
6758 /* If we had a constant that is cheaper than what we are now
6759 setting SRC to, use that constant. We ignored it when we
6760 thought we could make this into a no-op. */
6761 if (src_const && COST (src_const) < COST (src)
6762 && validate_change (insn, &SET_SRC (sets[i].rtl), src_const, 0))
6766 /* If we made a change, recompute SRC values. */
6767 if (src != sets[i].src)
6770 hash_arg_in_memory = 0;
6771 hash_arg_in_struct = 0;
6773 sets[i].src_hash = HASH (src, mode);
6774 sets[i].src_volatile = do_not_record;
6775 sets[i].src_in_memory = hash_arg_in_memory;
6776 sets[i].src_in_struct = hash_arg_in_struct;
6777 sets[i].src_elt = lookup (src, sets[i].src_hash, mode);
6780 /* If this is a single SET, we are setting a register, and we have an
6781 equivalent constant, we want to add a REG_NOTE. We don't want
6782 to write a REG_EQUAL note for a constant pseudo since verifying that
6783 that pseudo hasn't been eliminated is a pain. Such a note also
6784 won't help anything. */
6785 if (n_sets == 1 && src_const && GET_CODE (dest) == REG
6786 && GET_CODE (src_const) != REG)
6788 tem = find_reg_note (insn, REG_EQUAL, NULL_RTX);
6790 /* Record the actual constant value in a REG_EQUAL note, making
6791 a new one if one does not already exist. */
6793 XEXP (tem, 0) = src_const;
6795 REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_EQUAL,
6796 src_const, REG_NOTES (insn));
6798 /* If storing a constant value in a register that
6799 previously held the constant value 0,
6800 record this fact with a REG_WAS_0 note on this insn.
6802 Note that the *register* is required to have previously held 0,
6803 not just any register in the quantity and we must point to the
6804 insn that set that register to zero.
6806 Rather than track each register individually, we just see if
6807 the last set for this quantity was for this register. */
6809 if (REGNO_QTY_VALID_P (REGNO (dest))
6810 && qty_const[reg_qty[REGNO (dest)]] == const0_rtx)
6812 /* See if we previously had a REG_WAS_0 note. */
6813 rtx note = find_reg_note (insn, REG_WAS_0, NULL_RTX);
6814 rtx const_insn = qty_const_insn[reg_qty[REGNO (dest)]];
6816 if ((tem = single_set (const_insn)) != 0
6817 && rtx_equal_p (SET_DEST (tem), dest))
6820 XEXP (note, 0) = const_insn;
6822 REG_NOTES (insn) = gen_rtx (INSN_LIST, REG_WAS_0,
6823 const_insn, REG_NOTES (insn));
6828 /* Now deal with the destination. */
6830 sets[i].inner_dest_loc = &SET_DEST (sets[0].rtl);
6832 /* Look within any SIGN_EXTRACT or ZERO_EXTRACT
6833 to the MEM or REG within it. */
6834 while (GET_CODE (dest) == SIGN_EXTRACT
6835 || GET_CODE (dest) == ZERO_EXTRACT
6836 || GET_CODE (dest) == SUBREG
6837 || GET_CODE (dest) == STRICT_LOW_PART)
6839 sets[i].inner_dest_loc = &XEXP (dest, 0);
6840 dest = XEXP (dest, 0);
6843 sets[i].inner_dest = dest;
6845 if (GET_CODE (dest) == MEM)
6847 dest = fold_rtx (dest, insn);
6849 /* Decide whether we invalidate everything in memory,
6850 or just things at non-fixed places.
6851 Writing a large aggregate must invalidate everything
6852 because we don't know how long it is. */
6853 note_mem_written (dest, &writes_memory);
6856 /* Compute the hash code of the destination now,
6857 before the effects of this instruction are recorded,
6858 since the register values used in the address computation
6859 are those before this instruction. */
6860 sets[i].dest_hash = HASH (dest, mode);
6862 /* Don't enter a bit-field in the hash table
6863 because the value in it after the store
6864 may not equal what was stored, due to truncation. */
6866 if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT
6867 || GET_CODE (SET_DEST (sets[i].rtl)) == SIGN_EXTRACT)
6869 rtx width = XEXP (SET_DEST (sets[i].rtl), 1);
6871 if (src_const != 0 && GET_CODE (src_const) == CONST_INT
6872 && GET_CODE (width) == CONST_INT
6873 && INTVAL (width) < HOST_BITS_PER_WIDE_INT
6874 && ! (INTVAL (src_const)
6875 & ((HOST_WIDE_INT) (-1) << INTVAL (width))))
6876 /* Exception: if the value is constant,
6877 and it won't be truncated, record it. */
6881 /* This is chosen so that the destination will be invalidated
6882 but no new value will be recorded.
6883 We must invalidate because sometimes constant
6884 values can be recorded for bitfields. */
6885 sets[i].src_elt = 0;
6886 sets[i].src_volatile = 1;
6892 /* If only one set in a JUMP_INSN and it is now a no-op, we can delete
6894 else if (n_sets == 1 && dest == pc_rtx && src == pc_rtx)
6896 PUT_CODE (insn, NOTE);
6897 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
6898 NOTE_SOURCE_FILE (insn) = 0;
6899 cse_jumps_altered = 1;
6900 /* One less use of the label this insn used to jump to. */
6901 --LABEL_NUSES (JUMP_LABEL (insn));
6902 /* No more processing for this set. */
6906 /* If this SET is now setting PC to a label, we know it used to
6907 be a conditional or computed branch. So we see if we can follow
6908 it. If it was a computed branch, delete it and re-emit. */
6909 else if (dest == pc_rtx && GET_CODE (src) == LABEL_REF)
6913 /* If this is not in the format for a simple branch and
6914 we are the only SET in it, re-emit it. */
6915 if (! simplejump_p (insn) && n_sets == 1)
6917 rtx new = emit_jump_insn_before (gen_jump (XEXP (src, 0)), insn);
6918 JUMP_LABEL (new) = XEXP (src, 0);
6919 LABEL_NUSES (XEXP (src, 0))++;
6924 /* Otherwise, force rerecognition, since it probably had
6925 a different pattern before.
6926 This shouldn't really be necessary, since whatever
6927 changed the source value above should have done this.
6928 Until the right place is found, might as well do this here. */
6929 INSN_CODE (insn) = -1;
6931 /* Now that we've converted this jump to an unconditional jump,
6932 there is dead code after it. Delete the dead code until we
6933 reach a BARRIER, the end of the function, or a label. Do
6934 not delete NOTEs except for NOTE_INSN_DELETED since later
6935 phases assume these notes are retained. */
6939 while (NEXT_INSN (p) != 0
6940 && GET_CODE (NEXT_INSN (p)) != BARRIER
6941 && GET_CODE (NEXT_INSN (p)) != CODE_LABEL)
6943 if (GET_CODE (NEXT_INSN (p)) != NOTE
6944 || NOTE_LINE_NUMBER (NEXT_INSN (p)) == NOTE_INSN_DELETED)
6945 delete_insn (NEXT_INSN (p));
6950 /* If we don't have a BARRIER immediately after INSN, put one there.
6951 Much code assumes that there are no NOTEs between a JUMP_INSN and
6954 if (NEXT_INSN (insn) == 0
6955 || GET_CODE (NEXT_INSN (insn)) != BARRIER)
6956 emit_barrier_after (insn);
6958 /* We might have two BARRIERs separated by notes. Delete the second
6961 if (p != insn && NEXT_INSN (p) != 0
6962 && GET_CODE (NEXT_INSN (p)) == BARRIER)
6963 delete_insn (NEXT_INSN (p));
6965 cse_jumps_altered = 1;
6969 /* If destination is volatile, invalidate it and then do no further
6970 processing for this assignment. */
6972 else if (do_not_record)
6974 if (GET_CODE (dest) == REG || GET_CODE (dest) == SUBREG
6975 || GET_CODE (dest) == MEM)
6976 invalidate (dest, VOIDmode);
6977 else if (GET_CODE (dest) == STRICT_LOW_PART
6978 || GET_CODE (dest) == ZERO_EXTRACT)
6979 invalidate (XEXP (dest, 0), GET_MODE (dest));
6983 if (sets[i].rtl != 0 && dest != SET_DEST (sets[i].rtl))
6984 sets[i].dest_hash = HASH (SET_DEST (sets[i].rtl), mode);
6987 /* If setting CC0, record what it was set to, or a constant, if it
6988 is equivalent to a constant. If it is being set to a floating-point
6989 value, make a COMPARE with the appropriate constant of 0. If we
6990 don't do this, later code can interpret this as a test against
6991 const0_rtx, which can cause problems if we try to put it into an
6992 insn as a floating-point operand. */
6993 if (dest == cc0_rtx)
6995 this_insn_cc0 = src_const && mode != VOIDmode ? src_const : src;
6996 this_insn_cc0_mode = mode;
6997 if (FLOAT_MODE_P (mode))
6998 this_insn_cc0 = gen_rtx (COMPARE, VOIDmode, this_insn_cc0,
7004 /* Now enter all non-volatile source expressions in the hash table
7005 if they are not already present.
7006 Record their equivalence classes in src_elt.
7007 This way we can insert the corresponding destinations into
7008 the same classes even if the actual sources are no longer in them
7009 (having been invalidated). */
7011 if (src_eqv && src_eqv_elt == 0 && sets[0].rtl != 0 && ! src_eqv_volatile
7012 && ! rtx_equal_p (src_eqv, SET_DEST (sets[0].rtl)))
7014 register struct table_elt *elt;
7015 register struct table_elt *classp = sets[0].src_elt;
7016 rtx dest = SET_DEST (sets[0].rtl);
7017 enum machine_mode eqvmode = GET_MODE (dest);
7019 if (GET_CODE (dest) == STRICT_LOW_PART)
7021 eqvmode = GET_MODE (SUBREG_REG (XEXP (dest, 0)));
7024 if (insert_regs (src_eqv, classp, 0))
7026 rehash_using_reg (src_eqv);
7027 src_eqv_hash = HASH (src_eqv, eqvmode);
7029 elt = insert (src_eqv, classp, src_eqv_hash, eqvmode);
7030 elt->in_memory = src_eqv_in_memory;
7031 elt->in_struct = src_eqv_in_struct;
7034 /* Check to see if src_eqv_elt is the same as a set source which
7035 does not yet have an elt, and if so set the elt of the set source
7037 for (i = 0; i < n_sets; i++)
7038 if (sets[i].rtl && sets[i].src_elt == 0
7039 && rtx_equal_p (SET_SRC (sets[i].rtl), src_eqv))
7040 sets[i].src_elt = src_eqv_elt;
7043 for (i = 0; i < n_sets; i++)
7044 if (sets[i].rtl && ! sets[i].src_volatile
7045 && ! rtx_equal_p (SET_SRC (sets[i].rtl), SET_DEST (sets[i].rtl)))
7047 if (GET_CODE (SET_DEST (sets[i].rtl)) == STRICT_LOW_PART)
7049 /* REG_EQUAL in setting a STRICT_LOW_PART
7050 gives an equivalent for the entire destination register,
7051 not just for the subreg being stored in now.
7052 This is a more interesting equivalence, so we arrange later
7053 to treat the entire reg as the destination. */
7054 sets[i].src_elt = src_eqv_elt;
7055 sets[i].src_hash = src_eqv_hash;
7059 /* Insert source and constant equivalent into hash table, if not
7061 register struct table_elt *classp = src_eqv_elt;
7062 register rtx src = sets[i].src;
7063 register rtx dest = SET_DEST (sets[i].rtl);
7064 enum machine_mode mode
7065 = GET_MODE (src) == VOIDmode ? GET_MODE (dest) : GET_MODE (src);
7067 if (sets[i].src_elt == 0)
7069 register struct table_elt *elt;
7071 /* Note that these insert_regs calls cannot remove
7072 any of the src_elt's, because they would have failed to
7073 match if not still valid. */
7074 if (insert_regs (src, classp, 0))
7076 rehash_using_reg (src);
7077 sets[i].src_hash = HASH (src, mode);
7079 elt = insert (src, classp, sets[i].src_hash, mode);
7080 elt->in_memory = sets[i].src_in_memory;
7081 elt->in_struct = sets[i].src_in_struct;
7082 sets[i].src_elt = classp = elt;
7085 if (sets[i].src_const && sets[i].src_const_elt == 0
7086 && src != sets[i].src_const
7087 && ! rtx_equal_p (sets[i].src_const, src))
7088 sets[i].src_elt = insert (sets[i].src_const, classp,
7089 sets[i].src_const_hash, mode);
7092 else if (sets[i].src_elt == 0)
7093 /* If we did not insert the source into the hash table (e.g., it was
7094 volatile), note the equivalence class for the REG_EQUAL value, if any,
7095 so that the destination goes into that class. */
7096 sets[i].src_elt = src_eqv_elt;
7098 invalidate_from_clobbers (&writes_memory, x);
7100 /* Some registers are invalidated by subroutine calls. Memory is
7101 invalidated by non-constant calls. */
7103 if (GET_CODE (insn) == CALL_INSN)
7105 static struct write_data everything = {0, 1, 1, 1};
7107 if (! CONST_CALL_P (insn))
7108 invalidate_memory (&everything);
7109 invalidate_for_call ();
7112 /* Now invalidate everything set by this instruction.
7113 If a SUBREG or other funny destination is being set,
7114 sets[i].rtl is still nonzero, so here we invalidate the reg
7115 a part of which is being set. */
7117 for (i = 0; i < n_sets; i++)
7120 /* We can't use the inner dest, because the mode associated with
7121 a ZERO_EXTRACT is significant. */
7122 register rtx dest = SET_DEST (sets[i].rtl);
7124 /* Needed for registers to remove the register from its
7125 previous quantity's chain.
7126 Needed for memory if this is a nonvarying address, unless
7127 we have just done an invalidate_memory that covers even those. */
7128 if (GET_CODE (dest) == REG || GET_CODE (dest) == SUBREG
7129 || (GET_CODE (dest) == MEM && ! writes_memory.all
7130 && ! cse_rtx_addr_varies_p (dest)))
7131 invalidate (dest, VOIDmode);
7132 else if (GET_CODE (dest) == STRICT_LOW_PART
7133 || GET_CODE (dest) == ZERO_EXTRACT)
7134 invalidate (XEXP (dest, 0), GET_MODE (dest));
7137 /* Make sure registers mentioned in destinations
7138 are safe for use in an expression to be inserted.
7139 This removes from the hash table
7140 any invalid entry that refers to one of these registers.
7142 We don't care about the return value from mention_regs because
7143 we are going to hash the SET_DEST values unconditionally. */
7145 for (i = 0; i < n_sets; i++)
7146 if (sets[i].rtl && GET_CODE (SET_DEST (sets[i].rtl)) != REG)
7147 mention_regs (SET_DEST (sets[i].rtl));
7149 /* We may have just removed some of the src_elt's from the hash table.
7150 So replace each one with the current head of the same class. */
7152 for (i = 0; i < n_sets; i++)
7155 if (sets[i].src_elt && sets[i].src_elt->first_same_value == 0)
7156 /* If elt was removed, find current head of same class,
7157 or 0 if nothing remains of that class. */
7159 register struct table_elt *elt = sets[i].src_elt;
7161 while (elt && elt->prev_same_value)
7162 elt = elt->prev_same_value;
7164 while (elt && elt->first_same_value == 0)
7165 elt = elt->next_same_value;
7166 sets[i].src_elt = elt ? elt->first_same_value : 0;
7170 /* Now insert the destinations into their equivalence classes. */
7172 for (i = 0; i < n_sets; i++)
7175 register rtx dest = SET_DEST (sets[i].rtl);
7176 register struct table_elt *elt;
7178 /* Don't record value if we are not supposed to risk allocating
7179 floating-point values in registers that might be wider than
7181 if ((flag_float_store
7182 && GET_CODE (dest) == MEM
7183 && FLOAT_MODE_P (GET_MODE (dest)))
7184 /* Don't record values of destinations set inside a libcall block
7185 since we might delete the libcall. Things should have been set
7186 up so we won't want to reuse such a value, but we play it safe
7189 /* If we didn't put a REG_EQUAL value or a source into the hash
7190 table, there is no point is recording DEST. */
7191 || sets[i].src_elt == 0
7192 /* If DEST is a paradoxical SUBREG and SRC is a ZERO_EXTEND
7193 or SIGN_EXTEND, don't record DEST since it can cause
7194 some tracking to be wrong.
7196 ??? Think about this more later. */
7197 || (GET_CODE (dest) == SUBREG
7198 && (GET_MODE_SIZE (GET_MODE (dest))
7199 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))))
7200 && (GET_CODE (sets[i].src) == SIGN_EXTEND
7201 || GET_CODE (sets[i].src) == ZERO_EXTEND)))
7204 /* STRICT_LOW_PART isn't part of the value BEING set,
7205 and neither is the SUBREG inside it.
7206 Note that in this case SETS[I].SRC_ELT is really SRC_EQV_ELT. */
7207 if (GET_CODE (dest) == STRICT_LOW_PART)
7208 dest = SUBREG_REG (XEXP (dest, 0));
7210 if (GET_CODE (dest) == REG || GET_CODE (dest) == SUBREG)
7211 /* Registers must also be inserted into chains for quantities. */
7212 if (insert_regs (dest, sets[i].src_elt, 1))
7214 /* If `insert_regs' changes something, the hash code must be
7216 rehash_using_reg (dest);
7217 sets[i].dest_hash = HASH (dest, GET_MODE (dest));
7220 elt = insert (dest, sets[i].src_elt,
7221 sets[i].dest_hash, GET_MODE (dest));
7222 elt->in_memory = GET_CODE (sets[i].inner_dest) == MEM;
7225 /* This implicitly assumes a whole struct
7226 need not have MEM_IN_STRUCT_P.
7227 But a whole struct is *supposed* to have MEM_IN_STRUCT_P. */
7228 elt->in_struct = (MEM_IN_STRUCT_P (sets[i].inner_dest)
7229 || sets[i].inner_dest != SET_DEST (sets[i].rtl));
7232 /* If we have (set (subreg:m1 (reg:m2 foo) 0) (bar:m1)), M1 is no
7233 narrower than M2, and both M1 and M2 are the same number of words,
7234 we are also doing (set (reg:m2 foo) (subreg:m2 (bar:m1) 0)) so
7235 make that equivalence as well.
7237 However, BAR may have equivalences for which gen_lowpart_if_possible
7238 will produce a simpler value than gen_lowpart_if_possible applied to
7239 BAR (e.g., if BAR was ZERO_EXTENDed from M2), so we will scan all
7240 BAR's equivalences. If we don't get a simplified form, make
7241 the SUBREG. It will not be used in an equivalence, but will
7242 cause two similar assignments to be detected.
7244 Note the loop below will find SUBREG_REG (DEST) since we have
7245 already entered SRC and DEST of the SET in the table. */
7247 if (GET_CODE (dest) == SUBREG
7248 && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))) - 1)
7250 == (GET_MODE_SIZE (GET_MODE (dest)) - 1)/ UNITS_PER_WORD)
7251 && (GET_MODE_SIZE (GET_MODE (dest))
7252 >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))))
7253 && sets[i].src_elt != 0)
7255 enum machine_mode new_mode = GET_MODE (SUBREG_REG (dest));
7256 struct table_elt *elt, *classp = 0;
7258 for (elt = sets[i].src_elt->first_same_value; elt;
7259 elt = elt->next_same_value)
7263 struct table_elt *src_elt;
7265 /* Ignore invalid entries. */
7266 if (GET_CODE (elt->exp) != REG
7267 && ! exp_equiv_p (elt->exp, elt->exp, 1, 0))
7270 new_src = gen_lowpart_if_possible (new_mode, elt->exp);
7272 new_src = gen_rtx (SUBREG, new_mode, elt->exp, 0);
7274 src_hash = HASH (new_src, new_mode);
7275 src_elt = lookup (new_src, src_hash, new_mode);
7277 /* Put the new source in the hash table is if isn't
7281 if (insert_regs (new_src, classp, 0))
7283 rehash_using_reg (new_src);
7284 src_hash = HASH (new_src, new_mode);
7286 src_elt = insert (new_src, classp, src_hash, new_mode);
7287 src_elt->in_memory = elt->in_memory;
7288 src_elt->in_struct = elt->in_struct;
7290 else if (classp && classp != src_elt->first_same_value)
7291 /* Show that two things that we've seen before are
7292 actually the same. */
7293 merge_equiv_classes (src_elt, classp);
7295 classp = src_elt->first_same_value;
7300 /* Special handling for (set REG0 REG1)
7301 where REG0 is the "cheapest", cheaper than REG1.
7302 After cse, REG1 will probably not be used in the sequel,
7303 so (if easily done) change this insn to (set REG1 REG0) and
7304 replace REG1 with REG0 in the previous insn that computed their value.
7305 Then REG1 will become a dead store and won't cloud the situation
7306 for later optimizations.
7308 Do not make this change if REG1 is a hard register, because it will
7309 then be used in the sequel and we may be changing a two-operand insn
7310 into a three-operand insn.
7312 Also do not do this if we are operating on a copy of INSN. */
7314 if (n_sets == 1 && sets[0].rtl && GET_CODE (SET_DEST (sets[0].rtl)) == REG
7315 && NEXT_INSN (PREV_INSN (insn)) == insn
7316 && GET_CODE (SET_SRC (sets[0].rtl)) == REG
7317 && REGNO (SET_SRC (sets[0].rtl)) >= FIRST_PSEUDO_REGISTER
7318 && REGNO_QTY_VALID_P (REGNO (SET_SRC (sets[0].rtl)))
7319 && (qty_first_reg[reg_qty[REGNO (SET_SRC (sets[0].rtl))]]
7320 == REGNO (SET_DEST (sets[0].rtl))))
7322 rtx prev = PREV_INSN (insn);
7323 while (prev && GET_CODE (prev) == NOTE)
7324 prev = PREV_INSN (prev);
7326 if (prev && GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SET
7327 && SET_DEST (PATTERN (prev)) == SET_SRC (sets[0].rtl))
7329 rtx dest = SET_DEST (sets[0].rtl);
7330 rtx note = find_reg_note (prev, REG_EQUIV, NULL_RTX);
7332 validate_change (prev, & SET_DEST (PATTERN (prev)), dest, 1);
7333 validate_change (insn, & SET_DEST (sets[0].rtl),
7334 SET_SRC (sets[0].rtl), 1);
7335 validate_change (insn, & SET_SRC (sets[0].rtl), dest, 1);
7336 apply_change_group ();
7338 /* If REG1 was equivalent to a constant, REG0 is not. */
7340 PUT_REG_NOTE_KIND (note, REG_EQUAL);
7342 /* If there was a REG_WAS_0 note on PREV, remove it. Move
7343 any REG_WAS_0 note on INSN to PREV. */
7344 note = find_reg_note (prev, REG_WAS_0, NULL_RTX);
7346 remove_note (prev, note);
7348 note = find_reg_note (insn, REG_WAS_0, NULL_RTX);
7351 remove_note (insn, note);
7352 XEXP (note, 1) = REG_NOTES (prev);
7353 REG_NOTES (prev) = note;
7358 /* If this is a conditional jump insn, record any known equivalences due to
7359 the condition being tested. */
7361 last_jump_equiv_class = 0;
7362 if (GET_CODE (insn) == JUMP_INSN
7363 && n_sets == 1 && GET_CODE (x) == SET
7364 && GET_CODE (SET_SRC (x)) == IF_THEN_ELSE)
7365 record_jump_equiv (insn, 0);
7368 /* If the previous insn set CC0 and this insn no longer references CC0,
7369 delete the previous insn. Here we use the fact that nothing expects CC0
7370 to be valid over an insn, which is true until the final pass. */
7371 if (prev_insn && GET_CODE (prev_insn) == INSN
7372 && (tem = single_set (prev_insn)) != 0
7373 && SET_DEST (tem) == cc0_rtx
7374 && ! reg_mentioned_p (cc0_rtx, x))
7376 PUT_CODE (prev_insn, NOTE);
7377 NOTE_LINE_NUMBER (prev_insn) = NOTE_INSN_DELETED;
7378 NOTE_SOURCE_FILE (prev_insn) = 0;
7381 prev_insn_cc0 = this_insn_cc0;
7382 prev_insn_cc0_mode = this_insn_cc0_mode;
7388 /* Store 1 in *WRITES_PTR for those categories of memory ref
7389 that must be invalidated when the expression WRITTEN is stored in.
7390 If WRITTEN is null, say everything must be invalidated. */
7393 note_mem_written (written, writes_ptr)
7395 struct write_data *writes_ptr;
7397 static struct write_data everything = {0, 1, 1, 1};
7400 *writes_ptr = everything;
7401 else if (GET_CODE (written) == MEM)
7403 /* Pushing or popping the stack invalidates just the stack pointer. */
7404 rtx addr = XEXP (written, 0);
7405 if ((GET_CODE (addr) == PRE_DEC || GET_CODE (addr) == PRE_INC
7406 || GET_CODE (addr) == POST_DEC || GET_CODE (addr) == POST_INC)
7407 && GET_CODE (XEXP (addr, 0)) == REG
7408 && REGNO (XEXP (addr, 0)) == STACK_POINTER_REGNUM)
7413 else if (GET_MODE (written) == BLKmode)
7414 *writes_ptr = everything;
7415 /* (mem (scratch)) means clobber everything. */
7416 else if (GET_CODE (addr) == SCRATCH)
7417 *writes_ptr = everything;
7418 else if (cse_rtx_addr_varies_p (written))
7420 /* A varying address that is a sum indicates an array element,
7421 and that's just as good as a structure element
7422 in implying that we need not invalidate scalar variables.
7423 However, we must allow QImode aliasing of scalars, because the
7424 ANSI C standard allows character pointers to alias anything. */
7425 if (! ((MEM_IN_STRUCT_P (written)
7426 || GET_CODE (XEXP (written, 0)) == PLUS)
7427 && GET_MODE (written) != QImode))
7428 writes_ptr->all = 1;
7429 writes_ptr->nonscalar = 1;
7431 writes_ptr->var = 1;
7435 /* Perform invalidation on the basis of everything about an insn
7436 except for invalidating the actual places that are SET in it.
7437 This includes the places CLOBBERed, and anything that might
7438 alias with something that is SET or CLOBBERed.
7440 W points to the writes_memory for this insn, a struct write_data
7441 saying which kinds of memory references must be invalidated.
7442 X is the pattern of the insn. */
7445 invalidate_from_clobbers (w, x)
7446 struct write_data *w;
7449 /* If W->var is not set, W specifies no action.
7450 If W->all is set, this step gets all memory refs
7451 so they can be ignored in the rest of this function. */
7453 invalidate_memory (w);
7457 if (reg_tick[STACK_POINTER_REGNUM] >= 0)
7458 reg_tick[STACK_POINTER_REGNUM]++;
7460 /* This should be *very* rare. */
7461 if (TEST_HARD_REG_BIT (hard_regs_in_table, STACK_POINTER_REGNUM))
7462 invalidate (stack_pointer_rtx, VOIDmode);
7465 if (GET_CODE (x) == CLOBBER)
7467 rtx ref = XEXP (x, 0);
7470 if (GET_CODE (ref) == REG || GET_CODE (ref) == SUBREG
7471 || (GET_CODE (ref) == MEM && ! w->all))
7472 invalidate (ref, VOIDmode);
7473 else if (GET_CODE (ref) == STRICT_LOW_PART
7474 || GET_CODE (ref) == ZERO_EXTRACT)
7475 invalidate (XEXP (ref, 0), GET_MODE (ref));
7478 else if (GET_CODE (x) == PARALLEL)
7481 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
7483 register rtx y = XVECEXP (x, 0, i);
7484 if (GET_CODE (y) == CLOBBER)
7486 rtx ref = XEXP (y, 0);
7489 if (GET_CODE (ref) == REG || GET_CODE (ref) == SUBREG
7490 || (GET_CODE (ref) == MEM && !w->all))
7491 invalidate (ref, VOIDmode);
7492 else if (GET_CODE (ref) == STRICT_LOW_PART
7493 || GET_CODE (ref) == ZERO_EXTRACT)
7494 invalidate (XEXP (ref, 0), GET_MODE (ref));
7501 /* Process X, part of the REG_NOTES of an insn. Look at any REG_EQUAL notes
7502 and replace any registers in them with either an equivalent constant
7503 or the canonical form of the register. If we are inside an address,
7504 only do this if the address remains valid.
7506 OBJECT is 0 except when within a MEM in which case it is the MEM.
7508 Return the replacement for X. */
7511 cse_process_notes (x, object)
7515 enum rtx_code code = GET_CODE (x);
7516 char *fmt = GET_RTX_FORMAT (code);
7532 XEXP (x, 0) = cse_process_notes (XEXP (x, 0), x);
7537 if (REG_NOTE_KIND (x) == REG_EQUAL)
7538 XEXP (x, 0) = cse_process_notes (XEXP (x, 0), NULL_RTX);
7540 XEXP (x, 1) = cse_process_notes (XEXP (x, 1), NULL_RTX);
7546 rtx new = cse_process_notes (XEXP (x, 0), object);
7547 /* We don't substitute VOIDmode constants into these rtx,
7548 since they would impede folding. */
7549 if (GET_MODE (new) != VOIDmode)
7550 validate_change (object, &XEXP (x, 0), new, 0);
7555 i = reg_qty[REGNO (x)];
7557 /* Return a constant or a constant register. */
7558 if (REGNO_QTY_VALID_P (REGNO (x))
7559 && qty_const[i] != 0
7560 && (CONSTANT_P (qty_const[i])
7561 || GET_CODE (qty_const[i]) == REG))
7563 rtx new = gen_lowpart_if_possible (GET_MODE (x), qty_const[i]);
7568 /* Otherwise, canonicalize this register. */
7569 return canon_reg (x, NULL_RTX);
7572 for (i = 0; i < GET_RTX_LENGTH (code); i++)
7574 validate_change (object, &XEXP (x, i),
7575 cse_process_notes (XEXP (x, i), object), 0);
7580 /* Find common subexpressions between the end test of a loop and the beginning
7581 of the loop. LOOP_START is the CODE_LABEL at the start of a loop.
7583 Often we have a loop where an expression in the exit test is used
7584 in the body of the loop. For example "while (*p) *q++ = *p++;".
7585 Because of the way we duplicate the loop exit test in front of the loop,
7586 however, we don't detect that common subexpression. This will be caught
7587 when global cse is implemented, but this is a quite common case.
7589 This function handles the most common cases of these common expressions.
7590 It is called after we have processed the basic block ending with the
7591 NOTE_INSN_LOOP_END note that ends a loop and the previous JUMP_INSN
7592 jumps to a label used only once. */
7595 cse_around_loop (loop_start)
7600 struct table_elt *p;
7602 /* If the jump at the end of the loop doesn't go to the start, we don't
7604 for (insn = PREV_INSN (loop_start);
7605 insn && (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0);
7606 insn = PREV_INSN (insn))
7610 || GET_CODE (insn) != NOTE
7611 || NOTE_LINE_NUMBER (insn) != NOTE_INSN_LOOP_BEG)
7614 /* If the last insn of the loop (the end test) was an NE comparison,
7615 we will interpret it as an EQ comparison, since we fell through
7616 the loop. Any equivalences resulting from that comparison are
7617 therefore not valid and must be invalidated. */
7618 if (last_jump_equiv_class)
7619 for (p = last_jump_equiv_class->first_same_value; p;
7620 p = p->next_same_value)
7621 if (GET_CODE (p->exp) == MEM || GET_CODE (p->exp) == REG
7622 || (GET_CODE (p->exp) == SUBREG
7623 && GET_CODE (SUBREG_REG (p->exp)) == REG))
7624 invalidate (p->exp, VOIDmode);
7625 else if (GET_CODE (p->exp) == STRICT_LOW_PART
7626 || GET_CODE (p->exp) == ZERO_EXTRACT)
7627 invalidate (XEXP (p->exp, 0), GET_MODE (p->exp));
7629 /* Process insns starting after LOOP_START until we hit a CALL_INSN or
7630 a CODE_LABEL (we could handle a CALL_INSN, but it isn't worth it).
7632 The only thing we do with SET_DEST is invalidate entries, so we
7633 can safely process each SET in order. It is slightly less efficient
7634 to do so, but we only want to handle the most common cases. */
7636 for (insn = NEXT_INSN (loop_start);
7637 GET_CODE (insn) != CALL_INSN && GET_CODE (insn) != CODE_LABEL
7638 && ! (GET_CODE (insn) == NOTE
7639 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
7640 insn = NEXT_INSN (insn))
7642 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
7643 && (GET_CODE (PATTERN (insn)) == SET
7644 || GET_CODE (PATTERN (insn)) == CLOBBER))
7645 cse_set_around_loop (PATTERN (insn), insn, loop_start);
7646 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
7647 && GET_CODE (PATTERN (insn)) == PARALLEL)
7648 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
7649 if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET
7650 || GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == CLOBBER)
7651 cse_set_around_loop (XVECEXP (PATTERN (insn), 0, i), insn,
7656 /* Variable used for communications between the next two routines. */
7658 static struct write_data skipped_writes_memory;
7660 /* Process one SET of an insn that was skipped. We ignore CLOBBERs
7661 since they are done elsewhere. This function is called via note_stores. */
7664 invalidate_skipped_set (dest, set)
7668 if (GET_CODE (set) == CLOBBER
7675 if (GET_CODE (dest) == MEM)
7676 note_mem_written (dest, &skipped_writes_memory);
7678 /* There are times when an address can appear varying and be a PLUS
7679 during this scan when it would be a fixed address were we to know
7680 the proper equivalences. So promote "nonscalar" to be "all". */
7681 if (skipped_writes_memory.nonscalar)
7682 skipped_writes_memory.all = 1;
7684 if (GET_CODE (dest) == REG || GET_CODE (dest) == SUBREG
7685 || (! skipped_writes_memory.all && ! cse_rtx_addr_varies_p (dest)))
7686 invalidate (dest, VOIDmode);
7687 else if (GET_CODE (dest) == STRICT_LOW_PART
7688 || GET_CODE (dest) == ZERO_EXTRACT)
7689 invalidate (XEXP (dest, 0), GET_MODE (dest));
7692 /* Invalidate all insns from START up to the end of the function or the
7693 next label. This called when we wish to CSE around a block that is
7694 conditionally executed. */
7697 invalidate_skipped_block (start)
7701 static struct write_data init = {0, 0, 0, 0};
7702 static struct write_data everything = {0, 1, 1, 1};
7704 for (insn = start; insn && GET_CODE (insn) != CODE_LABEL;
7705 insn = NEXT_INSN (insn))
7707 if (GET_RTX_CLASS (GET_CODE (insn)) != 'i')
7710 skipped_writes_memory = init;
7712 if (GET_CODE (insn) == CALL_INSN)
7714 invalidate_for_call ();
7715 skipped_writes_memory = everything;
7718 note_stores (PATTERN (insn), invalidate_skipped_set);
7719 invalidate_from_clobbers (&skipped_writes_memory, PATTERN (insn));
7723 /* Used for communication between the following two routines; contains a
7724 value to be checked for modification. */
7726 static rtx cse_check_loop_start_value;
7728 /* If modifying X will modify the value in CSE_CHECK_LOOP_START_VALUE,
7729 indicate that fact by setting CSE_CHECK_LOOP_START_VALUE to 0. */
7732 cse_check_loop_start (x, set)
7736 if (cse_check_loop_start_value == 0
7737 || GET_CODE (x) == CC0 || GET_CODE (x) == PC)
7740 if ((GET_CODE (x) == MEM && GET_CODE (cse_check_loop_start_value) == MEM)
7741 || reg_overlap_mentioned_p (x, cse_check_loop_start_value))
7742 cse_check_loop_start_value = 0;
7745 /* X is a SET or CLOBBER contained in INSN that was found near the start of
7746 a loop that starts with the label at LOOP_START.
7748 If X is a SET, we see if its SET_SRC is currently in our hash table.
7749 If so, we see if it has a value equal to some register used only in the
7750 loop exit code (as marked by jump.c).
7752 If those two conditions are true, we search backwards from the start of
7753 the loop to see if that same value was loaded into a register that still
7754 retains its value at the start of the loop.
7756 If so, we insert an insn after the load to copy the destination of that
7757 load into the equivalent register and (try to) replace our SET_SRC with that
7760 In any event, we invalidate whatever this SET or CLOBBER modifies. */
7763 cse_set_around_loop (x, insn, loop_start)
7768 struct table_elt *src_elt;
7769 static struct write_data init = {0, 0, 0, 0};
7770 struct write_data writes_memory;
7772 writes_memory = init;
7774 /* If this is a SET, see if we can replace SET_SRC, but ignore SETs that
7775 are setting PC or CC0 or whose SET_SRC is already a register. */
7776 if (GET_CODE (x) == SET
7777 && GET_CODE (SET_DEST (x)) != PC && GET_CODE (SET_DEST (x)) != CC0
7778 && GET_CODE (SET_SRC (x)) != REG)
7780 src_elt = lookup (SET_SRC (x),
7781 HASH (SET_SRC (x), GET_MODE (SET_DEST (x))),
7782 GET_MODE (SET_DEST (x)));
7785 for (src_elt = src_elt->first_same_value; src_elt;
7786 src_elt = src_elt->next_same_value)
7787 if (GET_CODE (src_elt->exp) == REG && REG_LOOP_TEST_P (src_elt->exp)
7788 && COST (src_elt->exp) < COST (SET_SRC (x)))
7792 /* Look for an insn in front of LOOP_START that sets
7793 something in the desired mode to SET_SRC (x) before we hit
7794 a label or CALL_INSN. */
7796 for (p = prev_nonnote_insn (loop_start);
7797 p && GET_CODE (p) != CALL_INSN
7798 && GET_CODE (p) != CODE_LABEL;
7799 p = prev_nonnote_insn (p))
7800 if ((set = single_set (p)) != 0
7801 && GET_CODE (SET_DEST (set)) == REG
7802 && GET_MODE (SET_DEST (set)) == src_elt->mode
7803 && rtx_equal_p (SET_SRC (set), SET_SRC (x)))
7805 /* We now have to ensure that nothing between P
7806 and LOOP_START modified anything referenced in
7807 SET_SRC (x). We know that nothing within the loop
7808 can modify it, or we would have invalidated it in
7812 cse_check_loop_start_value = SET_SRC (x);
7813 for (q = p; q != loop_start; q = NEXT_INSN (q))
7814 if (GET_RTX_CLASS (GET_CODE (q)) == 'i')
7815 note_stores (PATTERN (q), cse_check_loop_start);
7817 /* If nothing was changed and we can replace our
7818 SET_SRC, add an insn after P to copy its destination
7819 to what we will be replacing SET_SRC with. */
7820 if (cse_check_loop_start_value
7821 && validate_change (insn, &SET_SRC (x),
7823 emit_insn_after (gen_move_insn (src_elt->exp,
7831 /* Now invalidate anything modified by X. */
7832 note_mem_written (SET_DEST (x), &writes_memory);
7834 if (writes_memory.var)
7835 invalidate_memory (&writes_memory);
7837 /* See comment on similar code in cse_insn for explanation of these tests. */
7838 if (GET_CODE (SET_DEST (x)) == REG || GET_CODE (SET_DEST (x)) == SUBREG
7839 || (GET_CODE (SET_DEST (x)) == MEM && ! writes_memory.all
7840 && ! cse_rtx_addr_varies_p (SET_DEST (x))))
7841 invalidate (SET_DEST (x), VOIDmode);
7842 else if (GET_CODE (SET_DEST (x)) == STRICT_LOW_PART
7843 || GET_CODE (SET_DEST (x)) == ZERO_EXTRACT)
7844 invalidate (XEXP (SET_DEST (x), 0), GET_MODE (SET_DEST (x)));
7847 /* Find the end of INSN's basic block and return its range,
7848 the total number of SETs in all the insns of the block, the last insn of the
7849 block, and the branch path.
7851 The branch path indicates which branches should be followed. If a non-zero
7852 path size is specified, the block should be rescanned and a different set
7853 of branches will be taken. The branch path is only used if
7854 FLAG_CSE_FOLLOW_JUMPS or FLAG_CSE_SKIP_BLOCKS is non-zero.
7856 DATA is a pointer to a struct cse_basic_block_data, defined below, that is
7857 used to describe the block. It is filled in with the information about
7858 the current block. The incoming structure's branch path, if any, is used
7859 to construct the output branch path. */
7862 cse_end_of_basic_block (insn, data, follow_jumps, after_loop, skip_blocks)
7864 struct cse_basic_block_data *data;
7871 int low_cuid = INSN_CUID (insn), high_cuid = INSN_CUID (insn);
7872 rtx next = GET_RTX_CLASS (GET_CODE (insn)) == 'i' ? insn : next_real_insn (insn);
7873 int path_size = data->path_size;
7877 /* Update the previous branch path, if any. If the last branch was
7878 previously TAKEN, mark it NOT_TAKEN. If it was previously NOT_TAKEN,
7879 shorten the path by one and look at the previous branch. We know that
7880 at least one branch must have been taken if PATH_SIZE is non-zero. */
7881 while (path_size > 0)
7883 if (data->path[path_size - 1].status != NOT_TAKEN)
7885 data->path[path_size - 1].status = NOT_TAKEN;
7892 /* Scan to end of this basic block. */
7893 while (p && GET_CODE (p) != CODE_LABEL)
7895 /* Don't cse out the end of a loop. This makes a difference
7896 only for the unusual loops that always execute at least once;
7897 all other loops have labels there so we will stop in any case.
7898 Cse'ing out the end of the loop is dangerous because it
7899 might cause an invariant expression inside the loop
7900 to be reused after the end of the loop. This would make it
7901 hard to move the expression out of the loop in loop.c,
7902 especially if it is one of several equivalent expressions
7903 and loop.c would like to eliminate it.
7905 If we are running after loop.c has finished, we can ignore
7906 the NOTE_INSN_LOOP_END. */
7908 if (! after_loop && GET_CODE (p) == NOTE
7909 && NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)
7912 /* Don't cse over a call to setjmp; on some machines (eg vax)
7913 the regs restored by the longjmp come from
7914 a later time than the setjmp. */
7915 if (GET_CODE (p) == NOTE
7916 && NOTE_LINE_NUMBER (p) == NOTE_INSN_SETJMP)
7919 /* A PARALLEL can have lots of SETs in it,
7920 especially if it is really an ASM_OPERANDS. */
7921 if (GET_RTX_CLASS (GET_CODE (p)) == 'i'
7922 && GET_CODE (PATTERN (p)) == PARALLEL)
7923 nsets += XVECLEN (PATTERN (p), 0);
7924 else if (GET_CODE (p) != NOTE)
7927 /* Ignore insns made by CSE; they cannot affect the boundaries of
7930 if (INSN_UID (p) <= max_uid && INSN_CUID (p) > high_cuid)
7931 high_cuid = INSN_CUID (p);
7932 if (INSN_UID (p) <= max_uid && INSN_CUID (p) < low_cuid)
7933 low_cuid = INSN_CUID (p);
7935 /* See if this insn is in our branch path. If it is and we are to
7937 if (path_entry < path_size && data->path[path_entry].branch == p)
7939 if (data->path[path_entry].status != NOT_TAKEN)
7942 /* Point to next entry in path, if any. */
7946 /* If this is a conditional jump, we can follow it if -fcse-follow-jumps
7947 was specified, we haven't reached our maximum path length, there are
7948 insns following the target of the jump, this is the only use of the
7949 jump label, and the target label is preceded by a BARRIER.
7951 Alternatively, we can follow the jump if it branches around a
7952 block of code and there are no other branches into the block.
7953 In this case invalidate_skipped_block will be called to invalidate any
7954 registers set in the block when following the jump. */
7956 else if ((follow_jumps || skip_blocks) && path_size < PATHLENGTH - 1
7957 && GET_CODE (p) == JUMP_INSN
7958 && GET_CODE (PATTERN (p)) == SET
7959 && GET_CODE (SET_SRC (PATTERN (p))) == IF_THEN_ELSE
7960 && LABEL_NUSES (JUMP_LABEL (p)) == 1
7961 && NEXT_INSN (JUMP_LABEL (p)) != 0)
7963 for (q = PREV_INSN (JUMP_LABEL (p)); q; q = PREV_INSN (q))
7964 if ((GET_CODE (q) != NOTE
7965 || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END
7966 || NOTE_LINE_NUMBER (q) == NOTE_INSN_SETJMP)
7967 && (GET_CODE (q) != CODE_LABEL || LABEL_NUSES (q) != 0))
7970 /* If we ran into a BARRIER, this code is an extension of the
7971 basic block when the branch is taken. */
7972 if (follow_jumps && q != 0 && GET_CODE (q) == BARRIER)
7974 /* Don't allow ourself to keep walking around an
7975 always-executed loop. */
7976 if (next_real_insn (q) == next)
7982 /* Similarly, don't put a branch in our path more than once. */
7983 for (i = 0; i < path_entry; i++)
7984 if (data->path[i].branch == p)
7987 if (i != path_entry)
7990 data->path[path_entry].branch = p;
7991 data->path[path_entry++].status = TAKEN;
7993 /* This branch now ends our path. It was possible that we
7994 didn't see this branch the last time around (when the
7995 insn in front of the target was a JUMP_INSN that was
7996 turned into a no-op). */
7997 path_size = path_entry;
8000 /* Mark block so we won't scan it again later. */
8001 PUT_MODE (NEXT_INSN (p), QImode);
8003 /* Detect a branch around a block of code. */
8004 else if (skip_blocks && q != 0 && GET_CODE (q) != CODE_LABEL)
8008 if (next_real_insn (q) == next)
8014 for (i = 0; i < path_entry; i++)
8015 if (data->path[i].branch == p)
8018 if (i != path_entry)
8021 /* This is no_labels_between_p (p, q) with an added check for
8022 reaching the end of a function (in case Q precedes P). */
8023 for (tmp = NEXT_INSN (p); tmp && tmp != q; tmp = NEXT_INSN (tmp))
8024 if (GET_CODE (tmp) == CODE_LABEL)
8029 data->path[path_entry].branch = p;
8030 data->path[path_entry++].status = AROUND;
8032 path_size = path_entry;
8035 /* Mark block so we won't scan it again later. */
8036 PUT_MODE (NEXT_INSN (p), QImode);
8043 data->low_cuid = low_cuid;
8044 data->high_cuid = high_cuid;
8045 data->nsets = nsets;
8048 /* If all jumps in the path are not taken, set our path length to zero
8049 so a rescan won't be done. */
8050 for (i = path_size - 1; i >= 0; i--)
8051 if (data->path[i].status != NOT_TAKEN)
8055 data->path_size = 0;
8057 data->path_size = path_size;
8059 /* End the current branch path. */
8060 data->path[path_size].branch = 0;
8063 /* Perform cse on the instructions of a function.
8064 F is the first instruction.
8065 NREGS is one plus the highest pseudo-reg number used in the instruction.
8067 AFTER_LOOP is 1 if this is the cse call done after loop optimization
8068 (only if -frerun-cse-after-loop).
8070 Returns 1 if jump_optimize should be redone due to simplifications
8071 in conditional jump instructions. */
8074 cse_main (f, nregs, after_loop, file)
8080 struct cse_basic_block_data val;
8081 register rtx insn = f;
8084 cse_jumps_altered = 0;
8085 constant_pool_entries_cost = 0;
8092 all_minus_one = (int *) alloca (nregs * sizeof (int));
8093 consec_ints = (int *) alloca (nregs * sizeof (int));
8095 for (i = 0; i < nregs; i++)
8097 all_minus_one[i] = -1;
8101 reg_next_eqv = (int *) alloca (nregs * sizeof (int));
8102 reg_prev_eqv = (int *) alloca (nregs * sizeof (int));
8103 reg_qty = (int *) alloca (nregs * sizeof (int));
8104 reg_in_table = (int *) alloca (nregs * sizeof (int));
8105 reg_tick = (int *) alloca (nregs * sizeof (int));
8107 #ifdef LOAD_EXTEND_OP
8109 /* Allocate scratch rtl here. cse_insn will fill in the memory reference
8110 and change the code and mode as appropriate. */
8111 memory_extend_rtx = gen_rtx (ZERO_EXTEND, VOIDmode, 0);
8114 /* Discard all the free elements of the previous function
8115 since they are allocated in the temporarily obstack. */
8116 bzero ((char *) table, sizeof table);
8117 free_element_chain = 0;
8118 n_elements_made = 0;
8120 /* Find the largest uid. */
8122 max_uid = get_max_uid ();
8123 uid_cuid = (int *) alloca ((max_uid + 1) * sizeof (int));
8124 bzero ((char *) uid_cuid, (max_uid + 1) * sizeof (int));
8126 /* Compute the mapping from uids to cuids.
8127 CUIDs are numbers assigned to insns, like uids,
8128 except that cuids increase monotonically through the code.
8129 Don't assign cuids to line-number NOTEs, so that the distance in cuids
8130 between two insns is not affected by -g. */
8132 for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
8134 if (GET_CODE (insn) != NOTE
8135 || NOTE_LINE_NUMBER (insn) < 0)
8136 INSN_CUID (insn) = ++i;
8138 /* Give a line number note the same cuid as preceding insn. */
8139 INSN_CUID (insn) = i;
8142 /* Initialize which registers are clobbered by calls. */
8144 CLEAR_HARD_REG_SET (regs_invalidated_by_call);
8146 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
8147 if ((call_used_regs[i]
8148 /* Used to check !fixed_regs[i] here, but that isn't safe;
8149 fixed regs are still call-clobbered, and sched can get
8150 confused if they can "live across calls".
8152 The frame pointer is always preserved across calls. The arg
8153 pointer is if it is fixed. The stack pointer usually is, unless
8154 RETURN_POPS_ARGS, in which case an explicit CLOBBER
8155 will be present. If we are generating PIC code, the PIC offset
8156 table register is preserved across calls. */
8158 && i != STACK_POINTER_REGNUM
8159 && i != FRAME_POINTER_REGNUM
8160 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
8161 && i != HARD_FRAME_POINTER_REGNUM
8163 #if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM
8164 && ! (i == ARG_POINTER_REGNUM && fixed_regs[i])
8166 #if defined (PIC_OFFSET_TABLE_REGNUM) && !defined (PIC_OFFSET_TABLE_REG_CALL_CLOBBERED)
8167 && ! (i == PIC_OFFSET_TABLE_REGNUM && flag_pic)
8171 SET_HARD_REG_BIT (regs_invalidated_by_call, i);
8173 /* Loop over basic blocks.
8174 Compute the maximum number of qty's needed for each basic block
8175 (which is 2 for each SET). */
8179 cse_end_of_basic_block (insn, &val, flag_cse_follow_jumps, after_loop,
8180 flag_cse_skip_blocks);
8182 /* If this basic block was already processed or has no sets, skip it. */
8183 if (val.nsets == 0 || GET_MODE (insn) == QImode)
8185 PUT_MODE (insn, VOIDmode);
8186 insn = (val.last ? NEXT_INSN (val.last) : 0);
8191 cse_basic_block_start = val.low_cuid;
8192 cse_basic_block_end = val.high_cuid;
8193 max_qty = val.nsets * 2;
8196 fprintf (file, ";; Processing block from %d to %d, %d sets.\n",
8197 INSN_UID (insn), val.last ? INSN_UID (val.last) : 0,
8200 /* Make MAX_QTY bigger to give us room to optimize
8201 past the end of this basic block, if that should prove useful. */
8207 /* If this basic block is being extended by following certain jumps,
8208 (see `cse_end_of_basic_block'), we reprocess the code from the start.
8209 Otherwise, we start after this basic block. */
8210 if (val.path_size > 0)
8211 cse_basic_block (insn, val.last, val.path, 0);
8214 int old_cse_jumps_altered = cse_jumps_altered;
8217 /* When cse changes a conditional jump to an unconditional
8218 jump, we want to reprocess the block, since it will give
8219 us a new branch path to investigate. */
8220 cse_jumps_altered = 0;
8221 temp = cse_basic_block (insn, val.last, val.path, ! after_loop);
8222 if (cse_jumps_altered == 0
8223 || (flag_cse_follow_jumps == 0 && flag_cse_skip_blocks == 0))
8226 cse_jumps_altered |= old_cse_jumps_altered;
8234 /* Tell refers_to_mem_p that qty_const info is not available. */
8237 if (max_elements_made < n_elements_made)
8238 max_elements_made = n_elements_made;
8240 return cse_jumps_altered;
8243 /* Process a single basic block. FROM and TO and the limits of the basic
8244 block. NEXT_BRANCH points to the branch path when following jumps or
8245 a null path when not following jumps.
8247 AROUND_LOOP is non-zero if we are to try to cse around to the start of a
8248 loop. This is true when we are being called for the last time on a
8249 block and this CSE pass is before loop.c. */
8252 cse_basic_block (from, to, next_branch, around_loop)
8253 register rtx from, to;
8254 struct branch_path *next_branch;
8259 int in_libcall_block = 0;
8261 /* Each of these arrays is undefined before max_reg, so only allocate
8262 the space actually needed and adjust the start below. */
8264 qty_first_reg = (int *) alloca ((max_qty - max_reg) * sizeof (int));
8265 qty_last_reg = (int *) alloca ((max_qty - max_reg) * sizeof (int));
8266 qty_mode= (enum machine_mode *) alloca ((max_qty - max_reg) * sizeof (enum machine_mode));
8267 qty_const = (rtx *) alloca ((max_qty - max_reg) * sizeof (rtx));
8268 qty_const_insn = (rtx *) alloca ((max_qty - max_reg) * sizeof (rtx));
8270 = (enum rtx_code *) alloca ((max_qty - max_reg) * sizeof (enum rtx_code));
8271 qty_comparison_qty = (int *) alloca ((max_qty - max_reg) * sizeof (int));
8272 qty_comparison_const = (rtx *) alloca ((max_qty - max_reg) * sizeof (rtx));
8274 qty_first_reg -= max_reg;
8275 qty_last_reg -= max_reg;
8276 qty_mode -= max_reg;
8277 qty_const -= max_reg;
8278 qty_const_insn -= max_reg;
8279 qty_comparison_code -= max_reg;
8280 qty_comparison_qty -= max_reg;
8281 qty_comparison_const -= max_reg;
8285 /* TO might be a label. If so, protect it from being deleted. */
8286 if (to != 0 && GET_CODE (to) == CODE_LABEL)
8289 for (insn = from; insn != to; insn = NEXT_INSN (insn))
8291 register enum rtx_code code;
8293 /* See if this is a branch that is part of the path. If so, and it is
8294 to be taken, do so. */
8295 if (next_branch->branch == insn)
8297 enum taken status = next_branch++->status;
8298 if (status != NOT_TAKEN)
8300 if (status == TAKEN)
8301 record_jump_equiv (insn, 1);
8303 invalidate_skipped_block (NEXT_INSN (insn));
8305 /* Set the last insn as the jump insn; it doesn't affect cc0.
8306 Then follow this branch. */
8311 insn = JUMP_LABEL (insn);
8316 code = GET_CODE (insn);
8317 if (GET_MODE (insn) == QImode)
8318 PUT_MODE (insn, VOIDmode);
8320 if (GET_RTX_CLASS (code) == 'i')
8322 /* Process notes first so we have all notes in canonical forms when
8323 looking for duplicate operations. */
8325 if (REG_NOTES (insn))
8326 REG_NOTES (insn) = cse_process_notes (REG_NOTES (insn), NULL_RTX);
8328 /* Track when we are inside in LIBCALL block. Inside such a block,
8329 we do not want to record destinations. The last insn of a
8330 LIBCALL block is not considered to be part of the block, since
8331 its destination is the result of the block and hence should be
8334 if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
8335 in_libcall_block = 1;
8336 else if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
8337 in_libcall_block = 0;
8339 cse_insn (insn, in_libcall_block);
8342 /* If INSN is now an unconditional jump, skip to the end of our
8343 basic block by pretending that we just did the last insn in the
8344 basic block. If we are jumping to the end of our block, show
8345 that we can have one usage of TO. */
8347 if (simplejump_p (insn))
8352 if (JUMP_LABEL (insn) == to)
8355 /* Maybe TO was deleted because the jump is unconditional.
8356 If so, there is nothing left in this basic block. */
8357 /* ??? Perhaps it would be smarter to set TO
8358 to whatever follows this insn,
8359 and pretend the basic block had always ended here. */
8360 if (INSN_DELETED_P (to))
8363 insn = PREV_INSN (to);
8366 /* See if it is ok to keep on going past the label
8367 which used to end our basic block. Remember that we incremented
8368 the count of that label, so we decrement it here. If we made
8369 a jump unconditional, TO_USAGE will be one; in that case, we don't
8370 want to count the use in that jump. */
8372 if (to != 0 && NEXT_INSN (insn) == to
8373 && GET_CODE (to) == CODE_LABEL && --LABEL_NUSES (to) == to_usage)
8375 struct cse_basic_block_data val;
8377 insn = NEXT_INSN (to);
8379 if (LABEL_NUSES (to) == 0)
8382 /* Find the end of the following block. Note that we won't be
8383 following branches in this case. If TO was the last insn
8384 in the function, we are done. Similarly, if we deleted the
8385 insn after TO, it must have been because it was preceded by
8386 a BARRIER. In that case, we are done with this block because it
8387 has no continuation. */
8389 if (insn == 0 || INSN_DELETED_P (insn))
8394 cse_end_of_basic_block (insn, &val, 0, 0, 0);
8396 /* If the tables we allocated have enough space left
8397 to handle all the SETs in the next basic block,
8398 continue through it. Otherwise, return,
8399 and that block will be scanned individually. */
8400 if (val.nsets * 2 + next_qty > max_qty)
8403 cse_basic_block_start = val.low_cuid;
8404 cse_basic_block_end = val.high_cuid;
8407 /* Prevent TO from being deleted if it is a label. */
8408 if (to != 0 && GET_CODE (to) == CODE_LABEL)
8411 /* Back up so we process the first insn in the extension. */
8412 insn = PREV_INSN (insn);
8416 if (next_qty > max_qty)
8419 /* If we are running before loop.c, we stopped on a NOTE_INSN_LOOP_END, and
8420 the previous insn is the only insn that branches to the head of a loop,
8421 we can cse into the loop. Don't do this if we changed the jump
8422 structure of a loop unless we aren't going to be following jumps. */
8424 if ((cse_jumps_altered == 0
8425 || (flag_cse_follow_jumps == 0 && flag_cse_skip_blocks == 0))
8426 && around_loop && to != 0
8427 && GET_CODE (to) == NOTE && NOTE_LINE_NUMBER (to) == NOTE_INSN_LOOP_END
8428 && GET_CODE (PREV_INSN (to)) == JUMP_INSN
8429 && JUMP_LABEL (PREV_INSN (to)) != 0
8430 && LABEL_NUSES (JUMP_LABEL (PREV_INSN (to))) == 1)
8431 cse_around_loop (JUMP_LABEL (PREV_INSN (to)));
8433 return to ? NEXT_INSN (to) : 0;
8436 /* Count the number of times registers are used (not set) in X.
8437 COUNTS is an array in which we accumulate the count, INCR is how much
8438 we count each register usage.
8440 Don't count a usage of DEST, which is the SET_DEST of a SET which
8441 contains X in its SET_SRC. This is because such a SET does not
8442 modify the liveness of DEST. */
8445 count_reg_usage (x, counts, dest, incr)
8458 switch (code = GET_CODE (x))
8462 counts[REGNO (x)] += incr;
8476 /* Unless we are setting a REG, count everything in SET_DEST. */
8477 if (GET_CODE (SET_DEST (x)) != REG)
8478 count_reg_usage (SET_DEST (x), counts, NULL_RTX, incr);
8480 /* If SRC has side-effects, then we can't delete this insn, so the
8481 usage of SET_DEST inside SRC counts.
8483 ??? Strictly-speaking, we might be preserving this insn
8484 because some other SET has side-effects, but that's hard
8485 to do and can't happen now. */
8486 count_reg_usage (SET_SRC (x), counts,
8487 side_effects_p (SET_SRC (x)) ? NULL_RTX : SET_DEST (x),
8492 count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, NULL_RTX, incr);
8494 /* ... falls through ... */
8497 count_reg_usage (PATTERN (x), counts, NULL_RTX, incr);
8499 /* Things used in a REG_EQUAL note aren't dead since loop may try to
8502 count_reg_usage (REG_NOTES (x), counts, NULL_RTX, incr);
8507 if (REG_NOTE_KIND (x) == REG_EQUAL
8508 || GET_CODE (XEXP (x,0)) == USE)
8509 count_reg_usage (XEXP (x, 0), counts, NULL_RTX, incr);
8510 count_reg_usage (XEXP (x, 1), counts, NULL_RTX, incr);
8514 fmt = GET_RTX_FORMAT (code);
8515 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
8518 count_reg_usage (XEXP (x, i), counts, dest, incr);
8519 else if (fmt[i] == 'E')
8520 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
8521 count_reg_usage (XVECEXP (x, i, j), counts, dest, incr);
8525 /* Scan all the insns and delete any that are dead; i.e., they store a register
8526 that is never used or they copy a register to itself.
8528 This is used to remove insns made obviously dead by cse. It improves the
8529 heuristics in loop since it won't try to move dead invariants out of loops
8530 or make givs for dead quantities. The remaining passes of the compilation
8531 are also sped up. */
8534 delete_dead_from_cse (insns, nreg)
8538 int *counts = (int *) alloca (nreg * sizeof (int));
8544 /* First count the number of times each register is used. */
8545 bzero ((char *) counts, sizeof (int) * nreg);
8546 for (insn = next_real_insn (insns); insn; insn = next_real_insn (insn))
8547 count_reg_usage (insn, counts, NULL_RTX, 1);
8549 /* Go from the last insn to the first and delete insns that only set unused
8550 registers or copy a register to itself. As we delete an insn, remove
8551 usage counts for registers it uses. */
8552 for (insn = prev_real_insn (get_last_insn ()); insn; insn = prev)
8556 prev = prev_real_insn (insn);
8558 /* Don't delete any insns that are part of a libcall block.
8559 Flow or loop might get confused if we did that. Remember
8560 that we are scanning backwards. */
8561 if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
8566 else if (GET_CODE (PATTERN (insn)) == SET)
8568 if (GET_CODE (SET_DEST (PATTERN (insn))) == REG
8569 && SET_DEST (PATTERN (insn)) == SET_SRC (PATTERN (insn)))
8573 else if (GET_CODE (SET_DEST (PATTERN (insn))) == CC0
8574 && ! side_effects_p (SET_SRC (PATTERN (insn)))
8575 && ((tem = next_nonnote_insn (insn)) == 0
8576 || GET_RTX_CLASS (GET_CODE (tem)) != 'i'
8577 || ! reg_referenced_p (cc0_rtx, PATTERN (tem))))
8580 else if (GET_CODE (SET_DEST (PATTERN (insn))) != REG
8581 || REGNO (SET_DEST (PATTERN (insn))) < FIRST_PSEUDO_REGISTER
8582 || counts[REGNO (SET_DEST (PATTERN (insn)))] != 0
8583 || side_effects_p (SET_SRC (PATTERN (insn))))
8586 else if (GET_CODE (PATTERN (insn)) == PARALLEL)
8587 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
8589 rtx elt = XVECEXP (PATTERN (insn), 0, i);
8591 if (GET_CODE (elt) == SET)
8593 if (GET_CODE (SET_DEST (elt)) == REG
8594 && SET_DEST (elt) == SET_SRC (elt))
8598 else if (GET_CODE (SET_DEST (elt)) == CC0
8599 && ! side_effects_p (SET_SRC (elt))
8600 && ((tem = next_nonnote_insn (insn)) == 0
8601 || GET_RTX_CLASS (GET_CODE (tem)) != 'i'
8602 || ! reg_referenced_p (cc0_rtx, PATTERN (tem))))
8605 else if (GET_CODE (SET_DEST (elt)) != REG
8606 || REGNO (SET_DEST (elt)) < FIRST_PSEUDO_REGISTER
8607 || counts[REGNO (SET_DEST (elt))] != 0
8608 || side_effects_p (SET_SRC (elt)))
8611 else if (GET_CODE (elt) != CLOBBER && GET_CODE (elt) != USE)
8617 /* If this is a dead insn, delete it and show registers in it aren't
8622 count_reg_usage (insn, counts, NULL_RTX, -1);
8626 if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))