1 /* Common subexpression elimination for GNU compiler.
2 Copyright (C) 1987, 88, 89, 92, 93, 94, 1995 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 (op_mode == VOIDmode)
2977 /* We don't know how to interpret negative-looking numbers in
2978 this case, so don't try to fold those. */
2982 else if (GET_MODE_BITSIZE (op_mode) >= HOST_BITS_PER_WIDE_INT * 2)
2985 hv = 0, lv &= GET_MODE_MASK (op_mode);
2987 #ifdef REAL_ARITHMETIC
2988 REAL_VALUE_FROM_UNSIGNED_INT (d, lv, hv);
2991 d = (double) (unsigned HOST_WIDE_INT) hv;
2992 d *= ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
2993 * (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
2994 d += (double) (unsigned HOST_WIDE_INT) lv;
2995 #endif /* REAL_ARITHMETIC */
2997 return CONST_DOUBLE_FROM_REAL_VALUE (d, mode);
3001 if (GET_CODE (op) == CONST_INT
3002 && width <= HOST_BITS_PER_WIDE_INT && width > 0)
3004 register HOST_WIDE_INT arg0 = INTVAL (op);
3005 register HOST_WIDE_INT val;
3018 val = (arg0 >= 0 ? arg0 : - arg0);
3022 /* Don't use ffs here. Instead, get low order bit and then its
3023 number. If arg0 is zero, this will return 0, as desired. */
3024 arg0 &= GET_MODE_MASK (mode);
3025 val = exact_log2 (arg0 & (- arg0)) + 1;
3033 if (op_mode == VOIDmode)
3035 if (GET_MODE_BITSIZE (op_mode) == HOST_BITS_PER_WIDE_INT)
3037 /* If we were really extending the mode,
3038 we would have to distinguish between zero-extension
3039 and sign-extension. */
3040 if (width != GET_MODE_BITSIZE (op_mode))
3044 else if (GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT)
3045 val = arg0 & ~((HOST_WIDE_INT) (-1) << GET_MODE_BITSIZE (op_mode));
3051 if (op_mode == VOIDmode)
3053 if (GET_MODE_BITSIZE (op_mode) == HOST_BITS_PER_WIDE_INT)
3055 /* If we were really extending the mode,
3056 we would have to distinguish between zero-extension
3057 and sign-extension. */
3058 if (width != GET_MODE_BITSIZE (op_mode))
3062 else if (GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT)
3065 = arg0 & ~((HOST_WIDE_INT) (-1) << GET_MODE_BITSIZE (op_mode));
3067 & ((HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (op_mode) - 1)))
3068 val -= (HOST_WIDE_INT) 1 << GET_MODE_BITSIZE (op_mode);
3081 /* Clear the bits that don't belong in our mode,
3082 unless they and our sign bit are all one.
3083 So we get either a reasonable negative value or a reasonable
3084 unsigned value for this mode. */
3085 if (width < HOST_BITS_PER_WIDE_INT
3086 && ((val & ((HOST_WIDE_INT) (-1) << (width - 1)))
3087 != ((HOST_WIDE_INT) (-1) << (width - 1))))
3088 val &= ((HOST_WIDE_INT) 1 << width) - 1;
3090 return GEN_INT (val);
3093 /* We can do some operations on integer CONST_DOUBLEs. Also allow
3094 for a DImode operation on a CONST_INT. */
3095 else if (GET_MODE (op) == VOIDmode && width <= HOST_BITS_PER_INT * 2
3096 && (GET_CODE (op) == CONST_DOUBLE || GET_CODE (op) == CONST_INT))
3098 HOST_WIDE_INT l1, h1, lv, hv;
3100 if (GET_CODE (op) == CONST_DOUBLE)
3101 l1 = CONST_DOUBLE_LOW (op), h1 = CONST_DOUBLE_HIGH (op);
3103 l1 = INTVAL (op), h1 = l1 < 0 ? -1 : 0;
3113 neg_double (l1, h1, &lv, &hv);
3118 neg_double (l1, h1, &lv, &hv);
3126 lv = HOST_BITS_PER_WIDE_INT + exact_log2 (h1 & (-h1)) + 1;
3128 lv = exact_log2 (l1 & (-l1)) + 1;
3132 /* This is just a change-of-mode, so do nothing. */
3137 if (op_mode == VOIDmode
3138 || GET_MODE_BITSIZE (op_mode) > HOST_BITS_PER_WIDE_INT)
3142 lv = l1 & GET_MODE_MASK (op_mode);
3146 if (op_mode == VOIDmode
3147 || GET_MODE_BITSIZE (op_mode) > HOST_BITS_PER_WIDE_INT)
3151 lv = l1 & GET_MODE_MASK (op_mode);
3152 if (GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT
3153 && (lv & ((HOST_WIDE_INT) 1
3154 << (GET_MODE_BITSIZE (op_mode) - 1))) != 0)
3155 lv -= (HOST_WIDE_INT) 1 << GET_MODE_BITSIZE (op_mode);
3157 hv = (lv < 0) ? ~ (HOST_WIDE_INT) 0 : 0;
3168 return immed_double_const (lv, hv, mode);
3171 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3172 else if (GET_CODE (op) == CONST_DOUBLE
3173 && GET_MODE_CLASS (mode) == MODE_FLOAT)
3179 if (setjmp (handler))
3180 /* There used to be a warning here, but that is inadvisable.
3181 People may want to cause traps, and the natural way
3182 to do it should not get a warning. */
3185 set_float_handler (handler);
3187 REAL_VALUE_FROM_CONST_DOUBLE (d, op);
3192 d = REAL_VALUE_NEGATE (d);
3196 if (REAL_VALUE_NEGATIVE (d))
3197 d = REAL_VALUE_NEGATE (d);
3200 case FLOAT_TRUNCATE:
3201 d = real_value_truncate (mode, d);
3205 /* All this does is change the mode. */
3209 d = REAL_VALUE_RNDZINT (d);
3213 d = REAL_VALUE_UNSIGNED_RNDZINT (d);
3223 x = CONST_DOUBLE_FROM_REAL_VALUE (d, mode);
3224 set_float_handler (NULL_PTR);
3228 else if (GET_CODE (op) == CONST_DOUBLE
3229 && GET_MODE_CLASS (GET_MODE (op)) == MODE_FLOAT
3230 && GET_MODE_CLASS (mode) == MODE_INT
3231 && width <= HOST_BITS_PER_WIDE_INT && width > 0)
3237 if (setjmp (handler))
3240 set_float_handler (handler);
3242 REAL_VALUE_FROM_CONST_DOUBLE (d, op);
3247 val = REAL_VALUE_FIX (d);
3251 val = REAL_VALUE_UNSIGNED_FIX (d);
3258 set_float_handler (NULL_PTR);
3260 /* Clear the bits that don't belong in our mode,
3261 unless they and our sign bit are all one.
3262 So we get either a reasonable negative value or a reasonable
3263 unsigned value for this mode. */
3264 if (width < HOST_BITS_PER_WIDE_INT
3265 && ((val & ((HOST_WIDE_INT) (-1) << (width - 1)))
3266 != ((HOST_WIDE_INT) (-1) << (width - 1))))
3267 val &= ((HOST_WIDE_INT) 1 << width) - 1;
3269 /* If this would be an entire word for the target, but is not for
3270 the host, then sign-extend on the host so that the number will look
3271 the same way on the host that it would on the target.
3273 For example, when building a 64 bit alpha hosted 32 bit sparc
3274 targeted compiler, then we want the 32 bit unsigned value -1 to be
3275 represented as a 64 bit value -1, and not as 0x00000000ffffffff.
3276 The later confuses the sparc backend. */
3278 if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT && BITS_PER_WORD == width
3279 && (val & ((HOST_WIDE_INT) 1 << (width - 1))))
3280 val |= ((HOST_WIDE_INT) (-1) << width);
3282 return GEN_INT (val);
3285 /* This was formerly used only for non-IEEE float.
3286 eggert@twinsun.com says it is safe for IEEE also. */
3289 /* There are some simplifications we can do even if the operands
3295 /* (not (not X)) == X, similarly for NEG. */
3296 if (GET_CODE (op) == code)
3297 return XEXP (op, 0);
3301 /* (sign_extend (truncate (minus (label_ref L1) (label_ref L2))))
3302 becomes just the MINUS if its mode is MODE. This allows
3303 folding switch statements on machines using casesi (such as
3305 if (GET_CODE (op) == TRUNCATE
3306 && GET_MODE (XEXP (op, 0)) == mode
3307 && GET_CODE (XEXP (op, 0)) == MINUS
3308 && GET_CODE (XEXP (XEXP (op, 0), 0)) == LABEL_REF
3309 && GET_CODE (XEXP (XEXP (op, 0), 1)) == LABEL_REF)
3310 return XEXP (op, 0);
3312 #ifdef POINTERS_EXTEND_UNSIGNED
3313 if (! POINTERS_EXTEND_UNSIGNED
3314 && mode == Pmode && GET_MODE (op) == ptr_mode
3316 return convert_memory_address (Pmode, op);
3320 #ifdef POINTERS_EXTEND_UNSIGNED
3322 if (POINTERS_EXTEND_UNSIGNED
3323 && mode == Pmode && GET_MODE (op) == ptr_mode
3325 return convert_memory_address (Pmode, op);
3334 /* Simplify a binary operation CODE with result mode MODE, operating on OP0
3335 and OP1. Return 0 if no simplification is possible.
3337 Don't use this for relational operations such as EQ or LT.
3338 Use simplify_relational_operation instead. */
3341 simplify_binary_operation (code, mode, op0, op1)
3343 enum machine_mode mode;
3346 register HOST_WIDE_INT arg0, arg1, arg0s, arg1s;
3348 int width = GET_MODE_BITSIZE (mode);
3351 /* Relational operations don't work here. We must know the mode
3352 of the operands in order to do the comparison correctly.
3353 Assuming a full word can give incorrect results.
3354 Consider comparing 128 with -128 in QImode. */
3356 if (GET_RTX_CLASS (code) == '<')
3359 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3360 if (GET_MODE_CLASS (mode) == MODE_FLOAT
3361 && GET_CODE (op0) == CONST_DOUBLE && GET_CODE (op1) == CONST_DOUBLE
3362 && mode == GET_MODE (op0) && mode == GET_MODE (op1))
3364 REAL_VALUE_TYPE f0, f1, value;
3367 if (setjmp (handler))
3370 set_float_handler (handler);
3372 REAL_VALUE_FROM_CONST_DOUBLE (f0, op0);
3373 REAL_VALUE_FROM_CONST_DOUBLE (f1, op1);
3374 f0 = real_value_truncate (mode, f0);
3375 f1 = real_value_truncate (mode, f1);
3377 #ifdef REAL_ARITHMETIC
3378 REAL_ARITHMETIC (value, rtx_to_tree_code (code), f0, f1);
3392 #ifndef REAL_INFINITY
3399 value = MIN (f0, f1);
3402 value = MAX (f0, f1);
3409 value = real_value_truncate (mode, value);
3410 set_float_handler (NULL_PTR);
3411 return CONST_DOUBLE_FROM_REAL_VALUE (value, mode);
3413 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
3415 /* We can fold some multi-word operations. */
3416 if (GET_MODE_CLASS (mode) == MODE_INT
3417 && width == HOST_BITS_PER_WIDE_INT * 2
3418 && (GET_CODE (op0) == CONST_DOUBLE || GET_CODE (op0) == CONST_INT)
3419 && (GET_CODE (op1) == CONST_DOUBLE || GET_CODE (op1) == CONST_INT))
3421 HOST_WIDE_INT l1, l2, h1, h2, lv, hv;
3423 if (GET_CODE (op0) == CONST_DOUBLE)
3424 l1 = CONST_DOUBLE_LOW (op0), h1 = CONST_DOUBLE_HIGH (op0);
3426 l1 = INTVAL (op0), h1 = l1 < 0 ? -1 : 0;
3428 if (GET_CODE (op1) == CONST_DOUBLE)
3429 l2 = CONST_DOUBLE_LOW (op1), h2 = CONST_DOUBLE_HIGH (op1);
3431 l2 = INTVAL (op1), h2 = l2 < 0 ? -1 : 0;
3436 /* A - B == A + (-B). */
3437 neg_double (l2, h2, &lv, &hv);
3440 /* .. fall through ... */
3443 add_double (l1, h1, l2, h2, &lv, &hv);
3447 mul_double (l1, h1, l2, h2, &lv, &hv);
3450 case DIV: case MOD: case UDIV: case UMOD:
3451 /* We'd need to include tree.h to do this and it doesn't seem worth
3456 lv = l1 & l2, hv = h1 & h2;
3460 lv = l1 | l2, hv = h1 | h2;
3464 lv = l1 ^ l2, hv = h1 ^ h2;
3470 && ((unsigned HOST_WIDE_INT) l1
3471 < (unsigned HOST_WIDE_INT) l2)))
3480 && ((unsigned HOST_WIDE_INT) l1
3481 > (unsigned HOST_WIDE_INT) l2)))
3488 if ((unsigned HOST_WIDE_INT) h1 < (unsigned HOST_WIDE_INT) h2
3490 && ((unsigned HOST_WIDE_INT) l1
3491 < (unsigned HOST_WIDE_INT) l2)))
3498 if ((unsigned HOST_WIDE_INT) h1 > (unsigned HOST_WIDE_INT) h2
3500 && ((unsigned HOST_WIDE_INT) l1
3501 > (unsigned HOST_WIDE_INT) l2)))
3507 case LSHIFTRT: case ASHIFTRT:
3509 case ROTATE: case ROTATERT:
3510 #ifdef SHIFT_COUNT_TRUNCATED
3511 if (SHIFT_COUNT_TRUNCATED)
3512 l2 &= (GET_MODE_BITSIZE (mode) - 1), h2 = 0;
3515 if (h2 != 0 || l2 < 0 || l2 >= GET_MODE_BITSIZE (mode))
3518 if (code == LSHIFTRT || code == ASHIFTRT)
3519 rshift_double (l1, h1, l2, GET_MODE_BITSIZE (mode), &lv, &hv,
3521 else if (code == ASHIFT)
3522 lshift_double (l1, h1, l2, GET_MODE_BITSIZE (mode), &lv, &hv, 1);
3523 else if (code == ROTATE)
3524 lrotate_double (l1, h1, l2, GET_MODE_BITSIZE (mode), &lv, &hv);
3525 else /* code == ROTATERT */
3526 rrotate_double (l1, h1, l2, GET_MODE_BITSIZE (mode), &lv, &hv);
3533 return immed_double_const (lv, hv, mode);
3536 if (GET_CODE (op0) != CONST_INT || GET_CODE (op1) != CONST_INT
3537 || width > HOST_BITS_PER_WIDE_INT || width == 0)
3539 /* Even if we can't compute a constant result,
3540 there are some cases worth simplifying. */
3545 /* In IEEE floating point, x+0 is not the same as x. Similarly
3546 for the other optimizations below. */
3547 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
3548 && FLOAT_MODE_P (mode) && ! flag_fast_math)
3551 if (op1 == CONST0_RTX (mode))
3554 /* ((-a) + b) -> (b - a) and similarly for (a + (-b)) */
3555 if (GET_CODE (op0) == NEG)
3556 return cse_gen_binary (MINUS, mode, op1, XEXP (op0, 0));
3557 else if (GET_CODE (op1) == NEG)
3558 return cse_gen_binary (MINUS, mode, op0, XEXP (op1, 0));
3560 /* Handle both-operands-constant cases. We can only add
3561 CONST_INTs to constants since the sum of relocatable symbols
3562 can't be handled by most assemblers. Don't add CONST_INT
3563 to CONST_INT since overflow won't be computed properly if wider
3564 than HOST_BITS_PER_WIDE_INT. */
3566 if (CONSTANT_P (op0) && GET_MODE (op0) != VOIDmode
3567 && GET_CODE (op1) == CONST_INT)
3568 return plus_constant (op0, INTVAL (op1));
3569 else if (CONSTANT_P (op1) && GET_MODE (op1) != VOIDmode
3570 && GET_CODE (op0) == CONST_INT)
3571 return plus_constant (op1, INTVAL (op0));
3573 /* See if this is something like X * C - X or vice versa or
3574 if the multiplication is written as a shift. If so, we can
3575 distribute and make a new multiply, shift, or maybe just
3576 have X (if C is 2 in the example above). But don't make
3577 real multiply if we didn't have one before. */
3579 if (! FLOAT_MODE_P (mode))
3581 HOST_WIDE_INT coeff0 = 1, coeff1 = 1;
3582 rtx lhs = op0, rhs = op1;
3585 if (GET_CODE (lhs) == NEG)
3586 coeff0 = -1, lhs = XEXP (lhs, 0);
3587 else if (GET_CODE (lhs) == MULT
3588 && GET_CODE (XEXP (lhs, 1)) == CONST_INT)
3590 coeff0 = INTVAL (XEXP (lhs, 1)), lhs = XEXP (lhs, 0);
3593 else if (GET_CODE (lhs) == ASHIFT
3594 && GET_CODE (XEXP (lhs, 1)) == CONST_INT
3595 && INTVAL (XEXP (lhs, 1)) >= 0
3596 && INTVAL (XEXP (lhs, 1)) < HOST_BITS_PER_WIDE_INT)
3598 coeff0 = ((HOST_WIDE_INT) 1) << INTVAL (XEXP (lhs, 1));
3599 lhs = XEXP (lhs, 0);
3602 if (GET_CODE (rhs) == NEG)
3603 coeff1 = -1, rhs = XEXP (rhs, 0);
3604 else if (GET_CODE (rhs) == MULT
3605 && GET_CODE (XEXP (rhs, 1)) == CONST_INT)
3607 coeff1 = INTVAL (XEXP (rhs, 1)), rhs = XEXP (rhs, 0);
3610 else if (GET_CODE (rhs) == ASHIFT
3611 && GET_CODE (XEXP (rhs, 1)) == CONST_INT
3612 && INTVAL (XEXP (rhs, 1)) >= 0
3613 && INTVAL (XEXP (rhs, 1)) < HOST_BITS_PER_WIDE_INT)
3615 coeff1 = ((HOST_WIDE_INT) 1) << INTVAL (XEXP (rhs, 1));
3616 rhs = XEXP (rhs, 0);
3619 if (rtx_equal_p (lhs, rhs))
3621 tem = cse_gen_binary (MULT, mode, lhs,
3622 GEN_INT (coeff0 + coeff1));
3623 return (GET_CODE (tem) == MULT && ! had_mult) ? 0 : tem;
3627 /* If one of the operands is a PLUS or a MINUS, see if we can
3628 simplify this by the associative law.
3629 Don't use the associative law for floating point.
3630 The inaccuracy makes it nonassociative,
3631 and subtle programs can break if operations are associated. */
3633 if (INTEGRAL_MODE_P (mode)
3634 && (GET_CODE (op0) == PLUS || GET_CODE (op0) == MINUS
3635 || GET_CODE (op1) == PLUS || GET_CODE (op1) == MINUS)
3636 && (tem = simplify_plus_minus (code, mode, op0, op1)) != 0)
3642 /* Convert (compare FOO (const_int 0)) to FOO unless we aren't
3643 using cc0, in which case we want to leave it as a COMPARE
3644 so we can distinguish it from a register-register-copy.
3646 In IEEE floating point, x-0 is not the same as x. */
3648 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3649 || ! FLOAT_MODE_P (mode) || flag_fast_math)
3650 && op1 == CONST0_RTX (mode))
3653 /* Do nothing here. */
3658 /* None of these optimizations can be done for IEEE
3660 if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
3661 && FLOAT_MODE_P (mode) && ! flag_fast_math)
3664 /* We can't assume x-x is 0 even with non-IEEE floating point,
3665 but since it is zero except in very strange circumstances, we
3666 will treat it as zero with -ffast-math. */
3667 if (rtx_equal_p (op0, op1)
3668 && ! side_effects_p (op0)
3669 && (! FLOAT_MODE_P (mode) || flag_fast_math))
3670 return CONST0_RTX (mode);
3672 /* Change subtraction from zero into negation. */
3673 if (op0 == CONST0_RTX (mode))
3674 return gen_rtx (NEG, mode, op1);
3676 /* (-1 - a) is ~a. */
3677 if (op0 == constm1_rtx)
3678 return gen_rtx (NOT, mode, op1);
3680 /* Subtracting 0 has no effect. */
3681 if (op1 == CONST0_RTX (mode))
3684 /* See if this is something like X * C - X or vice versa or
3685 if the multiplication is written as a shift. If so, we can
3686 distribute and make a new multiply, shift, or maybe just
3687 have X (if C is 2 in the example above). But don't make
3688 real multiply if we didn't have one before. */
3690 if (! FLOAT_MODE_P (mode))
3692 HOST_WIDE_INT coeff0 = 1, coeff1 = 1;
3693 rtx lhs = op0, rhs = op1;
3696 if (GET_CODE (lhs) == NEG)
3697 coeff0 = -1, lhs = XEXP (lhs, 0);
3698 else if (GET_CODE (lhs) == MULT
3699 && GET_CODE (XEXP (lhs, 1)) == CONST_INT)
3701 coeff0 = INTVAL (XEXP (lhs, 1)), lhs = XEXP (lhs, 0);
3704 else if (GET_CODE (lhs) == ASHIFT
3705 && GET_CODE (XEXP (lhs, 1)) == CONST_INT
3706 && INTVAL (XEXP (lhs, 1)) >= 0
3707 && INTVAL (XEXP (lhs, 1)) < HOST_BITS_PER_WIDE_INT)
3709 coeff0 = ((HOST_WIDE_INT) 1) << INTVAL (XEXP (lhs, 1));
3710 lhs = XEXP (lhs, 0);
3713 if (GET_CODE (rhs) == NEG)
3714 coeff1 = - 1, rhs = XEXP (rhs, 0);
3715 else if (GET_CODE (rhs) == MULT
3716 && GET_CODE (XEXP (rhs, 1)) == CONST_INT)
3718 coeff1 = INTVAL (XEXP (rhs, 1)), rhs = XEXP (rhs, 0);
3721 else if (GET_CODE (rhs) == ASHIFT
3722 && GET_CODE (XEXP (rhs, 1)) == CONST_INT
3723 && INTVAL (XEXP (rhs, 1)) >= 0
3724 && INTVAL (XEXP (rhs, 1)) < HOST_BITS_PER_WIDE_INT)
3726 coeff1 = ((HOST_WIDE_INT) 1) << INTVAL (XEXP (rhs, 1));
3727 rhs = XEXP (rhs, 0);
3730 if (rtx_equal_p (lhs, rhs))
3732 tem = cse_gen_binary (MULT, mode, lhs,
3733 GEN_INT (coeff0 - coeff1));
3734 return (GET_CODE (tem) == MULT && ! had_mult) ? 0 : tem;
3738 /* (a - (-b)) -> (a + b). */
3739 if (GET_CODE (op1) == NEG)
3740 return cse_gen_binary (PLUS, mode, op0, XEXP (op1, 0));
3742 /* If one of the operands is a PLUS or a MINUS, see if we can
3743 simplify this by the associative law.
3744 Don't use the associative law for floating point.
3745 The inaccuracy makes it nonassociative,
3746 and subtle programs can break if operations are associated. */
3748 if (INTEGRAL_MODE_P (mode)
3749 && (GET_CODE (op0) == PLUS || GET_CODE (op0) == MINUS
3750 || GET_CODE (op1) == PLUS || GET_CODE (op1) == MINUS)
3751 && (tem = simplify_plus_minus (code, mode, op0, op1)) != 0)
3754 /* Don't let a relocatable value get a negative coeff. */
3755 if (GET_CODE (op1) == CONST_INT && GET_MODE (op0) != VOIDmode)
3756 return plus_constant (op0, - INTVAL (op1));
3758 /* (x - (x & y)) -> (x & ~y) */
3759 if (GET_CODE (op1) == AND)
3761 if (rtx_equal_p (op0, XEXP (op1, 0)))
3762 return cse_gen_binary (AND, mode, op0, gen_rtx (NOT, mode, XEXP (op1, 1)));
3763 if (rtx_equal_p (op0, XEXP (op1, 1)))
3764 return cse_gen_binary (AND, mode, op0, gen_rtx (NOT, mode, XEXP (op1, 0)));
3769 if (op1 == constm1_rtx)
3771 tem = simplify_unary_operation (NEG, mode, op0, mode);
3773 return tem ? tem : gen_rtx (NEG, mode, op0);
3776 /* In IEEE floating point, x*0 is not always 0. */
3777 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3778 || ! FLOAT_MODE_P (mode) || flag_fast_math)
3779 && op1 == CONST0_RTX (mode)
3780 && ! side_effects_p (op0))
3783 /* In IEEE floating point, x*1 is not equivalent to x for nans.
3784 However, ANSI says we can drop signals,
3785 so we can do this anyway. */
3786 if (op1 == CONST1_RTX (mode))
3789 /* Convert multiply by constant power of two into shift unless
3790 we are still generating RTL. This test is a kludge. */
3791 if (GET_CODE (op1) == CONST_INT
3792 && (val = exact_log2 (INTVAL (op1))) >= 0
3793 && ! rtx_equal_function_value_matters)
3794 return gen_rtx (ASHIFT, mode, op0, GEN_INT (val));
3796 if (GET_CODE (op1) == CONST_DOUBLE
3797 && GET_MODE_CLASS (GET_MODE (op1)) == MODE_FLOAT)
3801 int op1is2, op1ism1;
3803 if (setjmp (handler))
3806 set_float_handler (handler);
3807 REAL_VALUE_FROM_CONST_DOUBLE (d, op1);
3808 op1is2 = REAL_VALUES_EQUAL (d, dconst2);
3809 op1ism1 = REAL_VALUES_EQUAL (d, dconstm1);
3810 set_float_handler (NULL_PTR);
3812 /* x*2 is x+x and x*(-1) is -x */
3813 if (op1is2 && GET_MODE (op0) == mode)
3814 return gen_rtx (PLUS, mode, op0, copy_rtx (op0));
3816 else if (op1ism1 && GET_MODE (op0) == mode)
3817 return gen_rtx (NEG, mode, op0);
3822 if (op1 == const0_rtx)
3824 if (GET_CODE (op1) == CONST_INT
3825 && (INTVAL (op1) & GET_MODE_MASK (mode)) == GET_MODE_MASK (mode))
3827 if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3829 /* A | (~A) -> -1 */
3830 if (((GET_CODE (op0) == NOT && rtx_equal_p (XEXP (op0, 0), op1))
3831 || (GET_CODE (op1) == NOT && rtx_equal_p (XEXP (op1, 0), op0)))
3832 && ! side_effects_p (op0)
3833 && GET_MODE_CLASS (mode) != MODE_CC)
3838 if (op1 == const0_rtx)
3840 if (GET_CODE (op1) == CONST_INT
3841 && (INTVAL (op1) & GET_MODE_MASK (mode)) == GET_MODE_MASK (mode))
3842 return gen_rtx (NOT, mode, op0);
3843 if (op0 == op1 && ! side_effects_p (op0)
3844 && GET_MODE_CLASS (mode) != MODE_CC)
3849 if (op1 == const0_rtx && ! side_effects_p (op0))
3851 if (GET_CODE (op1) == CONST_INT
3852 && (INTVAL (op1) & GET_MODE_MASK (mode)) == GET_MODE_MASK (mode))
3854 if (op0 == op1 && ! side_effects_p (op0)
3855 && GET_MODE_CLASS (mode) != MODE_CC)
3858 if (((GET_CODE (op0) == NOT && rtx_equal_p (XEXP (op0, 0), op1))
3859 || (GET_CODE (op1) == NOT && rtx_equal_p (XEXP (op1, 0), op0)))
3860 && ! side_effects_p (op0)
3861 && GET_MODE_CLASS (mode) != MODE_CC)
3866 /* Convert divide by power of two into shift (divide by 1 handled
3868 if (GET_CODE (op1) == CONST_INT
3869 && (arg1 = exact_log2 (INTVAL (op1))) > 0)
3870 return gen_rtx (LSHIFTRT, mode, op0, GEN_INT (arg1));
3872 /* ... fall through ... */
3875 if (op1 == CONST1_RTX (mode))
3878 /* In IEEE floating point, 0/x is not always 0. */
3879 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
3880 || ! FLOAT_MODE_P (mode) || flag_fast_math)
3881 && op0 == CONST0_RTX (mode)
3882 && ! side_effects_p (op1))
3885 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
3886 /* Change division by a constant into multiplication. Only do
3887 this with -ffast-math until an expert says it is safe in
3889 else if (GET_CODE (op1) == CONST_DOUBLE
3890 && GET_MODE_CLASS (GET_MODE (op1)) == MODE_FLOAT
3891 && op1 != CONST0_RTX (mode)
3895 REAL_VALUE_FROM_CONST_DOUBLE (d, op1);
3897 if (! REAL_VALUES_EQUAL (d, dconst0))
3899 #if defined (REAL_ARITHMETIC)
3900 REAL_ARITHMETIC (d, rtx_to_tree_code (DIV), dconst1, d);
3901 return gen_rtx (MULT, mode, op0,
3902 CONST_DOUBLE_FROM_REAL_VALUE (d, mode));
3904 return gen_rtx (MULT, mode, op0,
3905 CONST_DOUBLE_FROM_REAL_VALUE (1./d, mode));
3913 /* Handle modulus by power of two (mod with 1 handled below). */
3914 if (GET_CODE (op1) == CONST_INT
3915 && exact_log2 (INTVAL (op1)) > 0)
3916 return gen_rtx (AND, mode, op0, GEN_INT (INTVAL (op1) - 1));
3918 /* ... fall through ... */
3921 if ((op0 == const0_rtx || op1 == const1_rtx)
3922 && ! side_effects_p (op0) && ! side_effects_p (op1))
3928 /* Rotating ~0 always results in ~0. */
3929 if (GET_CODE (op0) == CONST_INT && width <= HOST_BITS_PER_WIDE_INT
3930 && INTVAL (op0) == GET_MODE_MASK (mode)
3931 && ! side_effects_p (op1))
3934 /* ... fall through ... */
3939 if (op1 == const0_rtx)
3941 if (op0 == const0_rtx && ! side_effects_p (op1))
3946 if (width <= HOST_BITS_PER_WIDE_INT && GET_CODE (op1) == CONST_INT
3947 && INTVAL (op1) == (HOST_WIDE_INT) 1 << (width -1)
3948 && ! side_effects_p (op0))
3950 else if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3955 if (width <= HOST_BITS_PER_WIDE_INT && GET_CODE (op1) == CONST_INT
3957 == (unsigned HOST_WIDE_INT) GET_MODE_MASK (mode) >> 1)
3958 && ! side_effects_p (op0))
3960 else if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3965 if (op1 == const0_rtx && ! side_effects_p (op0))
3967 else if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3972 if (op1 == constm1_rtx && ! side_effects_p (op0))
3974 else if (rtx_equal_p (op0, op1) && ! side_effects_p (op0))
3985 /* Get the integer argument values in two forms:
3986 zero-extended in ARG0, ARG1 and sign-extended in ARG0S, ARG1S. */
3988 arg0 = INTVAL (op0);
3989 arg1 = INTVAL (op1);
3991 if (width < HOST_BITS_PER_WIDE_INT)
3993 arg0 &= ((HOST_WIDE_INT) 1 << width) - 1;
3994 arg1 &= ((HOST_WIDE_INT) 1 << width) - 1;
3997 if (arg0s & ((HOST_WIDE_INT) 1 << (width - 1)))
3998 arg0s |= ((HOST_WIDE_INT) (-1) << width);
4001 if (arg1s & ((HOST_WIDE_INT) 1 << (width - 1)))
4002 arg1s |= ((HOST_WIDE_INT) (-1) << width);
4010 /* Compute the value of the arithmetic. */
4015 val = arg0s + arg1s;
4019 val = arg0s - arg1s;
4023 val = arg0s * arg1s;
4029 val = arg0s / arg1s;
4035 val = arg0s % arg1s;
4041 val = (unsigned HOST_WIDE_INT) arg0 / arg1;
4047 val = (unsigned HOST_WIDE_INT) arg0 % arg1;
4063 /* If shift count is undefined, don't fold it; let the machine do
4064 what it wants. But truncate it if the machine will do that. */
4068 #ifdef SHIFT_COUNT_TRUNCATED
4069 if (SHIFT_COUNT_TRUNCATED)
4073 val = ((unsigned HOST_WIDE_INT) arg0) >> arg1;
4080 #ifdef SHIFT_COUNT_TRUNCATED
4081 if (SHIFT_COUNT_TRUNCATED)
4085 val = ((unsigned HOST_WIDE_INT) arg0) << arg1;
4092 #ifdef SHIFT_COUNT_TRUNCATED
4093 if (SHIFT_COUNT_TRUNCATED)
4097 val = arg0s >> arg1;
4099 /* Bootstrap compiler may not have sign extended the right shift.
4100 Manually extend the sign to insure bootstrap cc matches gcc. */
4101 if (arg0s < 0 && arg1 > 0)
4102 val |= ((HOST_WIDE_INT) -1) << (HOST_BITS_PER_WIDE_INT - arg1);
4111 val = ((((unsigned HOST_WIDE_INT) arg0) << (width - arg1))
4112 | (((unsigned HOST_WIDE_INT) arg0) >> arg1));
4120 val = ((((unsigned HOST_WIDE_INT) arg0) << arg1)
4121 | (((unsigned HOST_WIDE_INT) arg0) >> (width - arg1)));
4125 /* Do nothing here. */
4129 val = arg0s <= arg1s ? arg0s : arg1s;
4133 val = ((unsigned HOST_WIDE_INT) arg0
4134 <= (unsigned HOST_WIDE_INT) arg1 ? arg0 : arg1);
4138 val = arg0s > arg1s ? arg0s : arg1s;
4142 val = ((unsigned HOST_WIDE_INT) arg0
4143 > (unsigned HOST_WIDE_INT) arg1 ? arg0 : arg1);
4150 /* Clear the bits that don't belong in our mode, unless they and our sign
4151 bit are all one. So we get either a reasonable negative value or a
4152 reasonable unsigned value for this mode. */
4153 if (width < HOST_BITS_PER_WIDE_INT
4154 && ((val & ((HOST_WIDE_INT) (-1) << (width - 1)))
4155 != ((HOST_WIDE_INT) (-1) << (width - 1))))
4156 val &= ((HOST_WIDE_INT) 1 << width) - 1;
4158 /* If this would be an entire word for the target, but is not for
4159 the host, then sign-extend on the host so that the number will look
4160 the same way on the host that it would on the target.
4162 For example, when building a 64 bit alpha hosted 32 bit sparc
4163 targeted compiler, then we want the 32 bit unsigned value -1 to be
4164 represented as a 64 bit value -1, and not as 0x00000000ffffffff.
4165 The later confuses the sparc backend. */
4167 if (BITS_PER_WORD < HOST_BITS_PER_WIDE_INT && BITS_PER_WORD == width
4168 && (val & ((HOST_WIDE_INT) 1 << (width - 1))))
4169 val |= ((HOST_WIDE_INT) (-1) << width);
4171 return GEN_INT (val);
4174 /* Simplify a PLUS or MINUS, at least one of whose operands may be another
4177 Rather than test for specific case, we do this by a brute-force method
4178 and do all possible simplifications until no more changes occur. Then
4179 we rebuild the operation. */
4182 simplify_plus_minus (code, mode, op0, op1)
4184 enum machine_mode mode;
4190 int n_ops = 2, input_ops = 2, input_consts = 0, n_consts = 0;
4191 int first = 1, negate = 0, changed;
4194 bzero ((char *) ops, sizeof ops);
4196 /* Set up the two operands and then expand them until nothing has been
4197 changed. If we run out of room in our array, give up; this should
4198 almost never happen. */
4200 ops[0] = op0, ops[1] = op1, negs[0] = 0, negs[1] = (code == MINUS);
4207 for (i = 0; i < n_ops; i++)
4208 switch (GET_CODE (ops[i]))
4215 ops[n_ops] = XEXP (ops[i], 1);
4216 negs[n_ops++] = GET_CODE (ops[i]) == MINUS ? !negs[i] : negs[i];
4217 ops[i] = XEXP (ops[i], 0);
4223 ops[i] = XEXP (ops[i], 0);
4224 negs[i] = ! negs[i];
4229 ops[i] = XEXP (ops[i], 0);
4235 /* ~a -> (-a - 1) */
4238 ops[n_ops] = constm1_rtx;
4239 negs[n_ops++] = negs[i];
4240 ops[i] = XEXP (ops[i], 0);
4241 negs[i] = ! negs[i];
4248 ops[i] = GEN_INT (- INTVAL (ops[i])), negs[i] = 0, changed = 1;
4253 /* If we only have two operands, we can't do anything. */
4257 /* Now simplify each pair of operands until nothing changes. The first
4258 time through just simplify constants against each other. */
4265 for (i = 0; i < n_ops - 1; i++)
4266 for (j = i + 1; j < n_ops; j++)
4267 if (ops[i] != 0 && ops[j] != 0
4268 && (! first || (CONSTANT_P (ops[i]) && CONSTANT_P (ops[j]))))
4270 rtx lhs = ops[i], rhs = ops[j];
4271 enum rtx_code ncode = PLUS;
4273 if (negs[i] && ! negs[j])
4274 lhs = ops[j], rhs = ops[i], ncode = MINUS;
4275 else if (! negs[i] && negs[j])
4278 tem = simplify_binary_operation (ncode, mode, lhs, rhs);
4281 ops[i] = tem, ops[j] = 0;
4282 negs[i] = negs[i] && negs[j];
4283 if (GET_CODE (tem) == NEG)
4284 ops[i] = XEXP (tem, 0), negs[i] = ! negs[i];
4286 if (GET_CODE (ops[i]) == CONST_INT && negs[i])
4287 ops[i] = GEN_INT (- INTVAL (ops[i])), negs[i] = 0;
4295 /* Pack all the operands to the lower-numbered entries and give up if
4296 we didn't reduce the number of operands we had. Make sure we
4297 count a CONST as two operands. If we have the same number of
4298 operands, but have made more CONSTs than we had, this is also
4299 an improvement, so accept it. */
4301 for (i = 0, j = 0; j < n_ops; j++)
4304 ops[i] = ops[j], negs[i++] = negs[j];
4305 if (GET_CODE (ops[j]) == CONST)
4309 if (i + n_consts > input_ops
4310 || (i + n_consts == input_ops && n_consts <= input_consts))
4315 /* If we have a CONST_INT, put it last. */
4316 for (i = 0; i < n_ops - 1; i++)
4317 if (GET_CODE (ops[i]) == CONST_INT)
4319 tem = ops[n_ops - 1], ops[n_ops - 1] = ops[i] , ops[i] = tem;
4320 j = negs[n_ops - 1], negs[n_ops - 1] = negs[i], negs[i] = j;
4323 /* Put a non-negated operand first. If there aren't any, make all
4324 operands positive and negate the whole thing later. */
4325 for (i = 0; i < n_ops && negs[i]; i++)
4330 for (i = 0; i < n_ops; i++)
4336 tem = ops[0], ops[0] = ops[i], ops[i] = tem;
4337 j = negs[0], negs[0] = negs[i], negs[i] = j;
4340 /* Now make the result by performing the requested operations. */
4342 for (i = 1; i < n_ops; i++)
4343 result = cse_gen_binary (negs[i] ? MINUS : PLUS, mode, result, ops[i]);
4345 return negate ? gen_rtx (NEG, mode, result) : result;
4348 /* Make a binary operation by properly ordering the operands and
4349 seeing if the expression folds. */
4352 cse_gen_binary (code, mode, op0, op1)
4354 enum machine_mode mode;
4359 /* Put complex operands first and constants second if commutative. */
4360 if (GET_RTX_CLASS (code) == 'c'
4361 && ((CONSTANT_P (op0) && GET_CODE (op1) != CONST_INT)
4362 || (GET_RTX_CLASS (GET_CODE (op0)) == 'o'
4363 && GET_RTX_CLASS (GET_CODE (op1)) != 'o')
4364 || (GET_CODE (op0) == SUBREG
4365 && GET_RTX_CLASS (GET_CODE (SUBREG_REG (op0))) == 'o'
4366 && GET_RTX_CLASS (GET_CODE (op1)) != 'o')))
4367 tem = op0, op0 = op1, op1 = tem;
4369 /* If this simplifies, do it. */
4370 tem = simplify_binary_operation (code, mode, op0, op1);
4375 /* Handle addition and subtraction of CONST_INT specially. Otherwise,
4376 just form the operation. */
4378 if (code == PLUS && GET_CODE (op1) == CONST_INT
4379 && GET_MODE (op0) != VOIDmode)
4380 return plus_constant (op0, INTVAL (op1));
4381 else if (code == MINUS && GET_CODE (op1) == CONST_INT
4382 && GET_MODE (op0) != VOIDmode)
4383 return plus_constant (op0, - INTVAL (op1));
4385 return gen_rtx (code, mode, op0, op1);
4388 /* Like simplify_binary_operation except used for relational operators.
4389 MODE is the mode of the operands, not that of the result. If MODE
4390 is VOIDmode, both operands must also be VOIDmode and we compare the
4391 operands in "infinite precision".
4393 If no simplification is possible, this function returns zero. Otherwise,
4394 it returns either const_true_rtx or const0_rtx. */
4397 simplify_relational_operation (code, mode, op0, op1)
4399 enum machine_mode mode;
4402 int equal, op0lt, op0ltu, op1lt, op1ltu;
4405 /* If op0 is a compare, extract the comparison arguments from it. */
4406 if (GET_CODE (op0) == COMPARE && op1 == const0_rtx)
4407 op1 = XEXP (op0, 1), op0 = XEXP (op0, 0);
4409 /* We can't simplify MODE_CC values since we don't know what the
4410 actual comparison is. */
4411 if (GET_MODE_CLASS (GET_MODE (op0)) == MODE_CC
4418 /* For integer comparisons of A and B maybe we can simplify A - B and can
4419 then simplify a comparison of that with zero. If A and B are both either
4420 a register or a CONST_INT, this can't help; testing for these cases will
4421 prevent infinite recursion here and speed things up.
4423 If CODE is an unsigned comparison, then we can never do this optimization,
4424 because it gives an incorrect result if the subtraction wraps around zero.
4425 ANSI C defines unsigned operations such that they never overflow, and
4426 thus such cases can not be ignored. */
4428 if (INTEGRAL_MODE_P (mode) && op1 != const0_rtx
4429 && ! ((GET_CODE (op0) == REG || GET_CODE (op0) == CONST_INT)
4430 && (GET_CODE (op1) == REG || GET_CODE (op1) == CONST_INT))
4431 && 0 != (tem = simplify_binary_operation (MINUS, mode, op0, op1))
4432 && code != GTU && code != GEU && code != LTU && code != LEU)
4433 return simplify_relational_operation (signed_condition (code),
4434 mode, tem, const0_rtx);
4436 /* For non-IEEE floating-point, if the two operands are equal, we know the
4438 if (rtx_equal_p (op0, op1)
4439 && (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
4440 || ! FLOAT_MODE_P (GET_MODE (op0)) || flag_fast_math))
4441 equal = 1, op0lt = 0, op0ltu = 0, op1lt = 0, op1ltu = 0;
4443 /* If the operands are floating-point constants, see if we can fold
4445 #if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
4446 else if (GET_CODE (op0) == CONST_DOUBLE && GET_CODE (op1) == CONST_DOUBLE
4447 && GET_MODE_CLASS (GET_MODE (op0)) == MODE_FLOAT)
4449 REAL_VALUE_TYPE d0, d1;
4452 if (setjmp (handler))
4455 set_float_handler (handler);
4456 REAL_VALUE_FROM_CONST_DOUBLE (d0, op0);
4457 REAL_VALUE_FROM_CONST_DOUBLE (d1, op1);
4458 equal = REAL_VALUES_EQUAL (d0, d1);
4459 op0lt = op0ltu = REAL_VALUES_LESS (d0, d1);
4460 op1lt = op1ltu = REAL_VALUES_LESS (d1, d0);
4461 set_float_handler (NULL_PTR);
4463 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
4465 /* Otherwise, see if the operands are both integers. */
4466 else if ((GET_MODE_CLASS (mode) == MODE_INT || mode == VOIDmode)
4467 && (GET_CODE (op0) == CONST_DOUBLE || GET_CODE (op0) == CONST_INT)
4468 && (GET_CODE (op1) == CONST_DOUBLE || GET_CODE (op1) == CONST_INT))
4470 int width = GET_MODE_BITSIZE (mode);
4471 HOST_WIDE_INT l0s, h0s, l1s, h1s;
4472 unsigned HOST_WIDE_INT l0u, h0u, l1u, h1u;
4474 /* Get the two words comprising each integer constant. */
4475 if (GET_CODE (op0) == CONST_DOUBLE)
4477 l0u = l0s = CONST_DOUBLE_LOW (op0);
4478 h0u = h0s = CONST_DOUBLE_HIGH (op0);
4482 l0u = l0s = INTVAL (op0);
4483 h0u = 0, h0s = l0s < 0 ? -1 : 0;
4486 if (GET_CODE (op1) == CONST_DOUBLE)
4488 l1u = l1s = CONST_DOUBLE_LOW (op1);
4489 h1u = h1s = CONST_DOUBLE_HIGH (op1);
4493 l1u = l1s = INTVAL (op1);
4494 h1u = 0, h1s = l1s < 0 ? -1 : 0;
4497 /* If WIDTH is nonzero and smaller than HOST_BITS_PER_WIDE_INT,
4498 we have to sign or zero-extend the values. */
4499 if (width != 0 && width <= HOST_BITS_PER_WIDE_INT)
4500 h0u = h1u = 0, h0s = l0s < 0 ? -1 : 0, h1s = l1s < 0 ? -1 : 0;
4502 if (width != 0 && width < HOST_BITS_PER_WIDE_INT)
4504 l0u &= ((HOST_WIDE_INT) 1 << width) - 1;
4505 l1u &= ((HOST_WIDE_INT) 1 << width) - 1;
4507 if (l0s & ((HOST_WIDE_INT) 1 << (width - 1)))
4508 l0s |= ((HOST_WIDE_INT) (-1) << width);
4510 if (l1s & ((HOST_WIDE_INT) 1 << (width - 1)))
4511 l1s |= ((HOST_WIDE_INT) (-1) << width);
4514 equal = (h0u == h1u && l0u == l1u);
4515 op0lt = (h0s < h1s || (h0s == h1s && l0s < l1s));
4516 op1lt = (h1s < h0s || (h1s == h0s && l1s < l0s));
4517 op0ltu = (h0u < h1u || (h0u == h1u && l0u < l1u));
4518 op1ltu = (h1u < h0u || (h1u == h0u && l1u < l0u));
4521 /* Otherwise, there are some code-specific tests we can make. */
4527 /* References to the frame plus a constant or labels cannot
4528 be zero, but a SYMBOL_REF can due to #pragma weak. */
4529 if (((NONZERO_BASE_PLUS_P (op0) && op1 == const0_rtx)
4530 || GET_CODE (op0) == LABEL_REF)
4531 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4532 /* On some machines, the ap reg can be 0 sometimes. */
4533 && op0 != arg_pointer_rtx
4540 if (((NONZERO_BASE_PLUS_P (op0) && op1 == const0_rtx)
4541 || GET_CODE (op0) == LABEL_REF)
4542 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
4543 && op0 != arg_pointer_rtx
4546 return const_true_rtx;
4550 /* Unsigned values are never negative. */
4551 if (op1 == const0_rtx)
4552 return const_true_rtx;
4556 if (op1 == const0_rtx)
4561 /* Unsigned values are never greater than the largest
4563 if (GET_CODE (op1) == CONST_INT
4564 && INTVAL (op1) == GET_MODE_MASK (mode)
4565 && INTEGRAL_MODE_P (mode))
4566 return const_true_rtx;
4570 if (GET_CODE (op1) == CONST_INT
4571 && INTVAL (op1) == GET_MODE_MASK (mode)
4572 && INTEGRAL_MODE_P (mode))
4580 /* If we reach here, EQUAL, OP0LT, OP0LTU, OP1LT, and OP1LTU are set
4585 return equal ? const_true_rtx : const0_rtx;
4587 return ! equal ? const_true_rtx : const0_rtx;
4589 return op0lt ? const_true_rtx : const0_rtx;
4591 return op1lt ? const_true_rtx : const0_rtx;
4593 return op0ltu ? const_true_rtx : const0_rtx;
4595 return op1ltu ? const_true_rtx : const0_rtx;
4597 return equal || op0lt ? const_true_rtx : const0_rtx;
4599 return equal || op1lt ? const_true_rtx : const0_rtx;
4601 return equal || op0ltu ? const_true_rtx : const0_rtx;
4603 return equal || op1ltu ? const_true_rtx : const0_rtx;
4609 /* Simplify CODE, an operation with result mode MODE and three operands,
4610 OP0, OP1, and OP2. OP0_MODE was the mode of OP0 before it became
4611 a constant. Return 0 if no simplifications is possible. */
4614 simplify_ternary_operation (code, mode, op0_mode, op0, op1, op2)
4616 enum machine_mode mode, op0_mode;
4619 int width = GET_MODE_BITSIZE (mode);
4621 /* VOIDmode means "infinite" precision. */
4623 width = HOST_BITS_PER_WIDE_INT;
4629 if (GET_CODE (op0) == CONST_INT
4630 && GET_CODE (op1) == CONST_INT
4631 && GET_CODE (op2) == CONST_INT
4632 && INTVAL (op1) + INTVAL (op2) <= GET_MODE_BITSIZE (op0_mode)
4633 && width <= HOST_BITS_PER_WIDE_INT)
4635 /* Extracting a bit-field from a constant */
4636 HOST_WIDE_INT val = INTVAL (op0);
4638 if (BITS_BIG_ENDIAN)
4639 val >>= (GET_MODE_BITSIZE (op0_mode)
4640 - INTVAL (op2) - INTVAL (op1));
4642 val >>= INTVAL (op2);
4644 if (HOST_BITS_PER_WIDE_INT != INTVAL (op1))
4646 /* First zero-extend. */
4647 val &= ((HOST_WIDE_INT) 1 << INTVAL (op1)) - 1;
4648 /* If desired, propagate sign bit. */
4649 if (code == SIGN_EXTRACT
4650 && (val & ((HOST_WIDE_INT) 1 << (INTVAL (op1) - 1))))
4651 val |= ~ (((HOST_WIDE_INT) 1 << INTVAL (op1)) - 1);
4654 /* Clear the bits that don't belong in our mode,
4655 unless they and our sign bit are all one.
4656 So we get either a reasonable negative value or a reasonable
4657 unsigned value for this mode. */
4658 if (width < HOST_BITS_PER_WIDE_INT
4659 && ((val & ((HOST_WIDE_INT) (-1) << (width - 1)))
4660 != ((HOST_WIDE_INT) (-1) << (width - 1))))
4661 val &= ((HOST_WIDE_INT) 1 << width) - 1;
4663 return GEN_INT (val);
4668 if (GET_CODE (op0) == CONST_INT)
4669 return op0 != const0_rtx ? op1 : op2;
4679 /* If X is a nontrivial arithmetic operation on an argument
4680 for which a constant value can be determined, return
4681 the result of operating on that value, as a constant.
4682 Otherwise, return X, possibly with one or more operands
4683 modified by recursive calls to this function.
4685 If X is a register whose contents are known, we do NOT
4686 return those contents here. equiv_constant is called to
4689 INSN is the insn that we may be modifying. If it is 0, make a copy
4690 of X before modifying it. */
4697 register enum rtx_code code;
4698 register enum machine_mode mode;
4705 /* Folded equivalents of first two operands of X. */
4709 /* Constant equivalents of first three operands of X;
4710 0 when no such equivalent is known. */
4715 /* The mode of the first operand of X. We need this for sign and zero
4717 enum machine_mode mode_arg0;
4722 mode = GET_MODE (x);
4723 code = GET_CODE (x);
4732 /* No use simplifying an EXPR_LIST
4733 since they are used only for lists of args
4734 in a function call's REG_EQUAL note. */
4740 return prev_insn_cc0;
4744 /* If the next insn is a CODE_LABEL followed by a jump table,
4745 PC's value is a LABEL_REF pointing to that label. That
4746 lets us fold switch statements on the Vax. */
4747 if (insn && GET_CODE (insn) == JUMP_INSN)
4749 rtx next = next_nonnote_insn (insn);
4751 if (next && GET_CODE (next) == CODE_LABEL
4752 && NEXT_INSN (next) != 0
4753 && GET_CODE (NEXT_INSN (next)) == JUMP_INSN
4754 && (GET_CODE (PATTERN (NEXT_INSN (next))) == ADDR_VEC
4755 || GET_CODE (PATTERN (NEXT_INSN (next))) == ADDR_DIFF_VEC))
4756 return gen_rtx (LABEL_REF, Pmode, next);
4761 /* See if we previously assigned a constant value to this SUBREG. */
4762 if ((new = lookup_as_function (x, CONST_INT)) != 0
4763 || (new = lookup_as_function (x, CONST_DOUBLE)) != 0)
4766 /* If this is a paradoxical SUBREG, we have no idea what value the
4767 extra bits would have. However, if the operand is equivalent
4768 to a SUBREG whose operand is the same as our mode, and all the
4769 modes are within a word, we can just use the inner operand
4770 because these SUBREGs just say how to treat the register.
4772 Similarly if we find an integer constant. */
4774 if (GET_MODE_SIZE (mode) > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
4776 enum machine_mode imode = GET_MODE (SUBREG_REG (x));
4777 struct table_elt *elt;
4779 if (GET_MODE_SIZE (mode) <= UNITS_PER_WORD
4780 && GET_MODE_SIZE (imode) <= UNITS_PER_WORD
4781 && (elt = lookup (SUBREG_REG (x), HASH (SUBREG_REG (x), imode),
4783 for (elt = elt->first_same_value;
4784 elt; elt = elt->next_same_value)
4786 if (CONSTANT_P (elt->exp)
4787 && GET_MODE (elt->exp) == VOIDmode)
4790 if (GET_CODE (elt->exp) == SUBREG
4791 && GET_MODE (SUBREG_REG (elt->exp)) == mode
4792 && exp_equiv_p (elt->exp, elt->exp, 1, 0))
4793 return copy_rtx (SUBREG_REG (elt->exp));
4799 /* Fold SUBREG_REG. If it changed, see if we can simplify the SUBREG.
4800 We might be able to if the SUBREG is extracting a single word in an
4801 integral mode or extracting the low part. */
4803 folded_arg0 = fold_rtx (SUBREG_REG (x), insn);
4804 const_arg0 = equiv_constant (folded_arg0);
4806 folded_arg0 = const_arg0;
4808 if (folded_arg0 != SUBREG_REG (x))
4812 if (GET_MODE_CLASS (mode) == MODE_INT
4813 && GET_MODE_SIZE (mode) == UNITS_PER_WORD
4814 && GET_MODE (SUBREG_REG (x)) != VOIDmode)
4815 new = operand_subword (folded_arg0, SUBREG_WORD (x), 0,
4816 GET_MODE (SUBREG_REG (x)));
4817 if (new == 0 && subreg_lowpart_p (x))
4818 new = gen_lowpart_if_possible (mode, folded_arg0);
4823 /* If this is a narrowing SUBREG and our operand is a REG, see if
4824 we can find an equivalence for REG that is an arithmetic operation
4825 in a wider mode where both operands are paradoxical SUBREGs
4826 from objects of our result mode. In that case, we couldn't report
4827 an equivalent value for that operation, since we don't know what the
4828 extra bits will be. But we can find an equivalence for this SUBREG
4829 by folding that operation is the narrow mode. This allows us to
4830 fold arithmetic in narrow modes when the machine only supports
4831 word-sized arithmetic.
4833 Also look for a case where we have a SUBREG whose operand is the
4834 same as our result. If both modes are smaller than a word, we
4835 are simply interpreting a register in different modes and we
4836 can use the inner value. */
4838 if (GET_CODE (folded_arg0) == REG
4839 && GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (folded_arg0))
4840 && subreg_lowpart_p (x))
4842 struct table_elt *elt;
4844 /* We can use HASH here since we know that canon_hash won't be
4846 elt = lookup (folded_arg0,
4847 HASH (folded_arg0, GET_MODE (folded_arg0)),
4848 GET_MODE (folded_arg0));
4851 elt = elt->first_same_value;
4853 for (; elt; elt = elt->next_same_value)
4855 enum rtx_code eltcode = GET_CODE (elt->exp);
4857 /* Just check for unary and binary operations. */
4858 if (GET_RTX_CLASS (GET_CODE (elt->exp)) == '1'
4859 && GET_CODE (elt->exp) != SIGN_EXTEND
4860 && GET_CODE (elt->exp) != ZERO_EXTEND
4861 && GET_CODE (XEXP (elt->exp, 0)) == SUBREG
4862 && GET_MODE (SUBREG_REG (XEXP (elt->exp, 0))) == mode)
4864 rtx op0 = SUBREG_REG (XEXP (elt->exp, 0));
4866 if (GET_CODE (op0) != REG && ! CONSTANT_P (op0))
4867 op0 = fold_rtx (op0, NULL_RTX);
4869 op0 = equiv_constant (op0);
4871 new = simplify_unary_operation (GET_CODE (elt->exp), mode,
4874 else if ((GET_RTX_CLASS (GET_CODE (elt->exp)) == '2'
4875 || GET_RTX_CLASS (GET_CODE (elt->exp)) == 'c')
4876 && eltcode != DIV && eltcode != MOD
4877 && eltcode != UDIV && eltcode != UMOD
4878 && eltcode != ASHIFTRT && eltcode != LSHIFTRT
4879 && eltcode != ROTATE && eltcode != ROTATERT
4880 && ((GET_CODE (XEXP (elt->exp, 0)) == SUBREG
4881 && (GET_MODE (SUBREG_REG (XEXP (elt->exp, 0)))
4883 || CONSTANT_P (XEXP (elt->exp, 0)))
4884 && ((GET_CODE (XEXP (elt->exp, 1)) == SUBREG
4885 && (GET_MODE (SUBREG_REG (XEXP (elt->exp, 1)))
4887 || CONSTANT_P (XEXP (elt->exp, 1))))
4889 rtx op0 = gen_lowpart_common (mode, XEXP (elt->exp, 0));
4890 rtx op1 = gen_lowpart_common (mode, XEXP (elt->exp, 1));
4892 if (op0 && GET_CODE (op0) != REG && ! CONSTANT_P (op0))
4893 op0 = fold_rtx (op0, NULL_RTX);
4896 op0 = equiv_constant (op0);
4898 if (op1 && GET_CODE (op1) != REG && ! CONSTANT_P (op1))
4899 op1 = fold_rtx (op1, NULL_RTX);
4902 op1 = equiv_constant (op1);
4904 /* If we are looking for the low SImode part of
4905 (ashift:DI c (const_int 32)), it doesn't work
4906 to compute that in SImode, because a 32-bit shift
4907 in SImode is unpredictable. We know the value is 0. */
4909 && GET_CODE (elt->exp) == ASHIFT
4910 && GET_CODE (op1) == CONST_INT
4911 && INTVAL (op1) >= GET_MODE_BITSIZE (mode))
4913 if (INTVAL (op1) < GET_MODE_BITSIZE (GET_MODE (elt->exp)))
4915 /* If the count fits in the inner mode's width,
4916 but exceeds the outer mode's width,
4917 the value will get truncated to 0
4921 /* If the count exceeds even the inner mode's width,
4922 don't fold this expression. */
4925 else if (op0 && op1)
4926 new = simplify_binary_operation (GET_CODE (elt->exp), mode,
4930 else if (GET_CODE (elt->exp) == SUBREG
4931 && GET_MODE (SUBREG_REG (elt->exp)) == mode
4932 && (GET_MODE_SIZE (GET_MODE (folded_arg0))
4934 && exp_equiv_p (elt->exp, elt->exp, 1, 0))
4935 new = copy_rtx (SUBREG_REG (elt->exp));
4946 /* If we have (NOT Y), see if Y is known to be (NOT Z).
4947 If so, (NOT Y) simplifies to Z. Similarly for NEG. */
4948 new = lookup_as_function (XEXP (x, 0), code);
4950 return fold_rtx (copy_rtx (XEXP (new, 0)), insn);
4954 /* If we are not actually processing an insn, don't try to find the
4955 best address. Not only don't we care, but we could modify the
4956 MEM in an invalid way since we have no insn to validate against. */
4958 find_best_addr (insn, &XEXP (x, 0));
4961 /* Even if we don't fold in the insn itself,
4962 we can safely do so here, in hopes of getting a constant. */
4963 rtx addr = fold_rtx (XEXP (x, 0), NULL_RTX);
4965 HOST_WIDE_INT offset = 0;
4967 if (GET_CODE (addr) == REG
4968 && REGNO_QTY_VALID_P (REGNO (addr))
4969 && GET_MODE (addr) == qty_mode[reg_qty[REGNO (addr)]]
4970 && qty_const[reg_qty[REGNO (addr)]] != 0)
4971 addr = qty_const[reg_qty[REGNO (addr)]];
4973 /* If address is constant, split it into a base and integer offset. */
4974 if (GET_CODE (addr) == SYMBOL_REF || GET_CODE (addr) == LABEL_REF)
4976 else if (GET_CODE (addr) == CONST && GET_CODE (XEXP (addr, 0)) == PLUS
4977 && GET_CODE (XEXP (XEXP (addr, 0), 1)) == CONST_INT)
4979 base = XEXP (XEXP (addr, 0), 0);
4980 offset = INTVAL (XEXP (XEXP (addr, 0), 1));
4982 else if (GET_CODE (addr) == LO_SUM
4983 && GET_CODE (XEXP (addr, 1)) == SYMBOL_REF)
4984 base = XEXP (addr, 1);
4986 /* If this is a constant pool reference, we can fold it into its
4987 constant to allow better value tracking. */
4988 if (base && GET_CODE (base) == SYMBOL_REF
4989 && CONSTANT_POOL_ADDRESS_P (base))
4991 rtx constant = get_pool_constant (base);
4992 enum machine_mode const_mode = get_pool_mode (base);
4995 if (CONSTANT_P (constant) && GET_CODE (constant) != CONST_INT)
4996 constant_pool_entries_cost = COST (constant);
4998 /* If we are loading the full constant, we have an equivalence. */
4999 if (offset == 0 && mode == const_mode)
5002 /* If this actually isn't a constant (wierd!), we can't do
5003 anything. Otherwise, handle the two most common cases:
5004 extracting a word from a multi-word constant, and extracting
5005 the low-order bits. Other cases don't seem common enough to
5007 if (! CONSTANT_P (constant))
5010 if (GET_MODE_CLASS (mode) == MODE_INT
5011 && GET_MODE_SIZE (mode) == UNITS_PER_WORD
5012 && offset % UNITS_PER_WORD == 0
5013 && (new = operand_subword (constant,
5014 offset / UNITS_PER_WORD,
5015 0, const_mode)) != 0)
5018 if (((BYTES_BIG_ENDIAN
5019 && offset == GET_MODE_SIZE (GET_MODE (constant)) - 1)
5020 || (! BYTES_BIG_ENDIAN && offset == 0))
5021 && (new = gen_lowpart_if_possible (mode, constant)) != 0)
5025 /* If this is a reference to a label at a known position in a jump
5026 table, we also know its value. */
5027 if (base && GET_CODE (base) == LABEL_REF)
5029 rtx label = XEXP (base, 0);
5030 rtx table_insn = NEXT_INSN (label);
5032 if (table_insn && GET_CODE (table_insn) == JUMP_INSN
5033 && GET_CODE (PATTERN (table_insn)) == ADDR_VEC)
5035 rtx table = PATTERN (table_insn);
5038 && (offset / GET_MODE_SIZE (GET_MODE (table))
5039 < XVECLEN (table, 0)))
5040 return XVECEXP (table, 0,
5041 offset / GET_MODE_SIZE (GET_MODE (table)));
5043 if (table_insn && GET_CODE (table_insn) == JUMP_INSN
5044 && GET_CODE (PATTERN (table_insn)) == ADDR_DIFF_VEC)
5046 rtx table = PATTERN (table_insn);
5049 && (offset / GET_MODE_SIZE (GET_MODE (table))
5050 < XVECLEN (table, 1)))
5052 offset /= GET_MODE_SIZE (GET_MODE (table));
5053 new = gen_rtx (MINUS, Pmode, XVECEXP (table, 1, offset),
5056 if (GET_MODE (table) != Pmode)
5057 new = gen_rtx (TRUNCATE, GET_MODE (table), new);
5059 /* Indicate this is a constant. This isn't a
5060 valid form of CONST, but it will only be used
5061 to fold the next insns and then discarded, so
5062 it should be safe. */
5063 return gen_rtx (CONST, GET_MODE (new), new);
5075 mode_arg0 = VOIDmode;
5077 /* Try folding our operands.
5078 Then see which ones have constant values known. */
5080 fmt = GET_RTX_FORMAT (code);
5081 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
5084 rtx arg = XEXP (x, i);
5085 rtx folded_arg = arg, const_arg = 0;
5086 enum machine_mode mode_arg = GET_MODE (arg);
5087 rtx cheap_arg, expensive_arg;
5088 rtx replacements[2];
5091 /* Most arguments are cheap, so handle them specially. */
5092 switch (GET_CODE (arg))
5095 /* This is the same as calling equiv_constant; it is duplicated
5097 if (REGNO_QTY_VALID_P (REGNO (arg))
5098 && qty_const[reg_qty[REGNO (arg)]] != 0
5099 && GET_CODE (qty_const[reg_qty[REGNO (arg)]]) != REG
5100 && GET_CODE (qty_const[reg_qty[REGNO (arg)]]) != PLUS)
5102 = gen_lowpart_if_possible (GET_MODE (arg),
5103 qty_const[reg_qty[REGNO (arg)]]);
5116 folded_arg = prev_insn_cc0;
5117 mode_arg = prev_insn_cc0_mode;
5118 const_arg = equiv_constant (folded_arg);
5123 folded_arg = fold_rtx (arg, insn);
5124 const_arg = equiv_constant (folded_arg);
5127 /* For the first three operands, see if the operand
5128 is constant or equivalent to a constant. */
5132 folded_arg0 = folded_arg;
5133 const_arg0 = const_arg;
5134 mode_arg0 = mode_arg;
5137 folded_arg1 = folded_arg;
5138 const_arg1 = const_arg;
5141 const_arg2 = const_arg;
5145 /* Pick the least expensive of the folded argument and an
5146 equivalent constant argument. */
5147 if (const_arg == 0 || const_arg == folded_arg
5148 || COST (const_arg) > COST (folded_arg))
5149 cheap_arg = folded_arg, expensive_arg = const_arg;
5151 cheap_arg = const_arg, expensive_arg = folded_arg;
5153 /* Try to replace the operand with the cheapest of the two
5154 possibilities. If it doesn't work and this is either of the first
5155 two operands of a commutative operation, try swapping them.
5156 If THAT fails, try the more expensive, provided it is cheaper
5157 than what is already there. */
5159 if (cheap_arg == XEXP (x, i))
5162 if (insn == 0 && ! copied)
5168 replacements[0] = cheap_arg, replacements[1] = expensive_arg;
5170 j < 2 && replacements[j]
5171 && COST (replacements[j]) < COST (XEXP (x, i));
5174 if (validate_change (insn, &XEXP (x, i), replacements[j], 0))
5177 if (code == NE || code == EQ || GET_RTX_CLASS (code) == 'c')
5179 validate_change (insn, &XEXP (x, i), XEXP (x, 1 - i), 1);
5180 validate_change (insn, &XEXP (x, 1 - i), replacements[j], 1);
5182 if (apply_change_group ())
5184 /* Swap them back to be invalid so that this loop can
5185 continue and flag them to be swapped back later. */
5188 tem = XEXP (x, 0); XEXP (x, 0) = XEXP (x, 1);
5197 else if (fmt[i] == 'E')
5198 /* Don't try to fold inside of a vector of expressions.
5199 Doing nothing is harmless. */
5202 /* If a commutative operation, place a constant integer as the second
5203 operand unless the first operand is also a constant integer. Otherwise,
5204 place any constant second unless the first operand is also a constant. */
5206 if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
5208 if (must_swap || (const_arg0
5210 || (GET_CODE (const_arg0) == CONST_INT
5211 && GET_CODE (const_arg1) != CONST_INT))))
5213 register rtx tem = XEXP (x, 0);
5215 if (insn == 0 && ! copied)
5221 validate_change (insn, &XEXP (x, 0), XEXP (x, 1), 1);
5222 validate_change (insn, &XEXP (x, 1), tem, 1);
5223 if (apply_change_group ())
5225 tem = const_arg0, const_arg0 = const_arg1, const_arg1 = tem;
5226 tem = folded_arg0, folded_arg0 = folded_arg1, folded_arg1 = tem;
5231 /* If X is an arithmetic operation, see if we can simplify it. */
5233 switch (GET_RTX_CLASS (code))
5239 /* We can't simplify extension ops unless we know the
5241 if ((code == ZERO_EXTEND || code == SIGN_EXTEND)
5242 && mode_arg0 == VOIDmode)
5245 /* If we had a CONST, strip it off and put it back later if we
5247 if (const_arg0 != 0 && GET_CODE (const_arg0) == CONST)
5248 is_const = 1, const_arg0 = XEXP (const_arg0, 0);
5250 new = simplify_unary_operation (code, mode,
5251 const_arg0 ? const_arg0 : folded_arg0,
5253 if (new != 0 && is_const)
5254 new = gen_rtx (CONST, mode, new);
5259 /* See what items are actually being compared and set FOLDED_ARG[01]
5260 to those values and CODE to the actual comparison code. If any are
5261 constant, set CONST_ARG0 and CONST_ARG1 appropriately. We needn't
5262 do anything if both operands are already known to be constant. */
5264 if (const_arg0 == 0 || const_arg1 == 0)
5266 struct table_elt *p0, *p1;
5267 rtx true = const_true_rtx, false = const0_rtx;
5268 enum machine_mode mode_arg1;
5270 #ifdef FLOAT_STORE_FLAG_VALUE
5271 if (GET_MODE_CLASS (mode) == MODE_FLOAT)
5273 true = CONST_DOUBLE_FROM_REAL_VALUE (FLOAT_STORE_FLAG_VALUE,
5275 false = CONST0_RTX (mode);
5279 code = find_comparison_args (code, &folded_arg0, &folded_arg1,
5280 &mode_arg0, &mode_arg1);
5281 const_arg0 = equiv_constant (folded_arg0);
5282 const_arg1 = equiv_constant (folded_arg1);
5284 /* If the mode is VOIDmode or a MODE_CC mode, we don't know
5285 what kinds of things are being compared, so we can't do
5286 anything with this comparison. */
5288 if (mode_arg0 == VOIDmode || GET_MODE_CLASS (mode_arg0) == MODE_CC)
5291 /* If we do not now have two constants being compared, see if we
5292 can nevertheless deduce some things about the comparison. */
5293 if (const_arg0 == 0 || const_arg1 == 0)
5295 /* Is FOLDED_ARG0 frame-pointer plus a constant? Or non-explicit
5296 constant? These aren't zero, but we don't know their sign. */
5297 if (const_arg1 == const0_rtx
5298 && (NONZERO_BASE_PLUS_P (folded_arg0)
5299 #if 0 /* Sad to say, on sysvr4, #pragma weak can make a symbol address
5301 || GET_CODE (folded_arg0) == SYMBOL_REF
5303 || GET_CODE (folded_arg0) == LABEL_REF
5304 || GET_CODE (folded_arg0) == CONST))
5308 else if (code == NE)
5312 /* See if the two operands are the same. We don't do this
5313 for IEEE floating-point since we can't assume x == x
5314 since x might be a NaN. */
5316 if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
5317 || ! FLOAT_MODE_P (mode_arg0) || flag_fast_math)
5318 && (folded_arg0 == folded_arg1
5319 || (GET_CODE (folded_arg0) == REG
5320 && GET_CODE (folded_arg1) == REG
5321 && (reg_qty[REGNO (folded_arg0)]
5322 == reg_qty[REGNO (folded_arg1)]))
5323 || ((p0 = lookup (folded_arg0,
5324 (safe_hash (folded_arg0, mode_arg0)
5325 % NBUCKETS), mode_arg0))
5326 && (p1 = lookup (folded_arg1,
5327 (safe_hash (folded_arg1, mode_arg0)
5328 % NBUCKETS), mode_arg0))
5329 && p0->first_same_value == p1->first_same_value)))
5330 return ((code == EQ || code == LE || code == GE
5331 || code == LEU || code == GEU)
5334 /* If FOLDED_ARG0 is a register, see if the comparison we are
5335 doing now is either the same as we did before or the reverse
5336 (we only check the reverse if not floating-point). */
5337 else if (GET_CODE (folded_arg0) == REG)
5339 int qty = reg_qty[REGNO (folded_arg0)];
5341 if (REGNO_QTY_VALID_P (REGNO (folded_arg0))
5342 && (comparison_dominates_p (qty_comparison_code[qty], code)
5343 || (comparison_dominates_p (qty_comparison_code[qty],
5344 reverse_condition (code))
5345 && ! FLOAT_MODE_P (mode_arg0)))
5346 && (rtx_equal_p (qty_comparison_const[qty], folded_arg1)
5348 && rtx_equal_p (qty_comparison_const[qty],
5350 || (GET_CODE (folded_arg1) == REG
5351 && (reg_qty[REGNO (folded_arg1)]
5352 == qty_comparison_qty[qty]))))
5353 return (comparison_dominates_p (qty_comparison_code[qty],
5360 /* If we are comparing against zero, see if the first operand is
5361 equivalent to an IOR with a constant. If so, we may be able to
5362 determine the result of this comparison. */
5364 if (const_arg1 == const0_rtx)
5366 rtx y = lookup_as_function (folded_arg0, IOR);
5370 && (inner_const = equiv_constant (XEXP (y, 1))) != 0
5371 && GET_CODE (inner_const) == CONST_INT
5372 && INTVAL (inner_const) != 0)
5374 int sign_bitnum = GET_MODE_BITSIZE (mode_arg0) - 1;
5375 int has_sign = (HOST_BITS_PER_WIDE_INT >= sign_bitnum
5376 && (INTVAL (inner_const)
5377 & ((HOST_WIDE_INT) 1 << sign_bitnum)));
5378 rtx true = const_true_rtx, false = const0_rtx;
5380 #ifdef FLOAT_STORE_FLAG_VALUE
5381 if (GET_MODE_CLASS (mode) == MODE_FLOAT)
5383 true = CONST_DOUBLE_FROM_REAL_VALUE (FLOAT_STORE_FLAG_VALUE,
5385 false = CONST0_RTX (mode);
5407 new = simplify_relational_operation (code, mode_arg0,
5408 const_arg0 ? const_arg0 : folded_arg0,
5409 const_arg1 ? const_arg1 : folded_arg1);
5410 #ifdef FLOAT_STORE_FLAG_VALUE
5411 if (new != 0 && GET_MODE_CLASS (mode) == MODE_FLOAT)
5412 new = ((new == const0_rtx) ? CONST0_RTX (mode)
5413 : CONST_DOUBLE_FROM_REAL_VALUE (FLOAT_STORE_FLAG_VALUE, mode));
5422 /* If the second operand is a LABEL_REF, see if the first is a MINUS
5423 with that LABEL_REF as its second operand. If so, the result is
5424 the first operand of that MINUS. This handles switches with an
5425 ADDR_DIFF_VEC table. */
5426 if (const_arg1 && GET_CODE (const_arg1) == LABEL_REF)
5429 = GET_CODE (folded_arg0) == MINUS ? folded_arg0
5430 : lookup_as_function (folded_arg0, MINUS);
5432 if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF
5433 && XEXP (XEXP (y, 1), 0) == XEXP (const_arg1, 0))
5436 /* Now try for a CONST of a MINUS like the above. */
5437 if ((y = (GET_CODE (folded_arg0) == CONST ? folded_arg0
5438 : lookup_as_function (folded_arg0, CONST))) != 0
5439 && GET_CODE (XEXP (y, 0)) == MINUS
5440 && GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF
5441 && XEXP (XEXP (XEXP (y, 0),1), 0) == XEXP (const_arg1, 0))
5442 return XEXP (XEXP (y, 0), 0);
5445 /* Likewise if the operands are in the other order. */
5446 if (const_arg0 && GET_CODE (const_arg0) == LABEL_REF)
5449 = GET_CODE (folded_arg1) == MINUS ? folded_arg1
5450 : lookup_as_function (folded_arg1, MINUS);
5452 if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF
5453 && XEXP (XEXP (y, 1), 0) == XEXP (const_arg0, 0))
5456 /* Now try for a CONST of a MINUS like the above. */
5457 if ((y = (GET_CODE (folded_arg1) == CONST ? folded_arg1
5458 : lookup_as_function (folded_arg1, CONST))) != 0
5459 && GET_CODE (XEXP (y, 0)) == MINUS
5460 && GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF
5461 && XEXP (XEXP (XEXP (y, 0),1), 0) == XEXP (const_arg0, 0))
5462 return XEXP (XEXP (y, 0), 0);
5465 /* If second operand is a register equivalent to a negative
5466 CONST_INT, see if we can find a register equivalent to the
5467 positive constant. Make a MINUS if so. Don't do this for
5468 a negative constant since we might then alternate between
5469 chosing positive and negative constants. Having the positive
5470 constant previously-used is the more common case. */
5471 if (const_arg1 && GET_CODE (const_arg1) == CONST_INT
5472 && INTVAL (const_arg1) < 0 && GET_CODE (folded_arg1) == REG)
5474 rtx new_const = GEN_INT (- INTVAL (const_arg1));
5476 = lookup (new_const, safe_hash (new_const, mode) % NBUCKETS,
5480 for (p = p->first_same_value; p; p = p->next_same_value)
5481 if (GET_CODE (p->exp) == REG)
5482 return cse_gen_binary (MINUS, mode, folded_arg0,
5483 canon_reg (p->exp, NULL_RTX));
5488 /* If we have (MINUS Y C), see if Y is known to be (PLUS Z C2).
5489 If so, produce (PLUS Z C2-C). */
5490 if (const_arg1 != 0 && GET_CODE (const_arg1) == CONST_INT)
5492 rtx y = lookup_as_function (XEXP (x, 0), PLUS);
5493 if (y && GET_CODE (XEXP (y, 1)) == CONST_INT)
5494 return fold_rtx (plus_constant (copy_rtx (y),
5495 -INTVAL (const_arg1)),
5499 /* ... fall through ... */
5502 case SMIN: case SMAX: case UMIN: case UMAX:
5503 case IOR: case AND: case XOR:
5504 case MULT: case DIV: case UDIV:
5505 case ASHIFT: case LSHIFTRT: case ASHIFTRT:
5506 /* If we have (<op> <reg> <const_int>) for an associative OP and REG
5507 is known to be of similar form, we may be able to replace the
5508 operation with a combined operation. This may eliminate the
5509 intermediate operation if every use is simplified in this way.
5510 Note that the similar optimization done by combine.c only works
5511 if the intermediate operation's result has only one reference. */
5513 if (GET_CODE (folded_arg0) == REG
5514 && const_arg1 && GET_CODE (const_arg1) == CONST_INT)
5517 = (code == ASHIFT || code == ASHIFTRT || code == LSHIFTRT);
5518 rtx y = lookup_as_function (folded_arg0, code);
5520 enum rtx_code associate_code;
5524 || 0 == (inner_const
5525 = equiv_constant (fold_rtx (XEXP (y, 1), 0)))
5526 || GET_CODE (inner_const) != CONST_INT
5527 /* If we have compiled a statement like
5528 "if (x == (x & mask1))", and now are looking at
5529 "x & mask2", we will have a case where the first operand
5530 of Y is the same as our first operand. Unless we detect
5531 this case, an infinite loop will result. */
5532 || XEXP (y, 0) == folded_arg0)
5535 /* Don't associate these operations if they are a PLUS with the
5536 same constant and it is a power of two. These might be doable
5537 with a pre- or post-increment. Similarly for two subtracts of
5538 identical powers of two with post decrement. */
5540 if (code == PLUS && INTVAL (const_arg1) == INTVAL (inner_const)
5542 #if defined(HAVE_PRE_INCREMENT) || defined(HAVE_POST_INCREMENT)
5543 || exact_log2 (INTVAL (const_arg1)) >= 0
5545 #if defined(HAVE_PRE_DECREMENT) || defined(HAVE_POST_DECREMENT)
5546 || exact_log2 (- INTVAL (const_arg1)) >= 0
5551 /* Compute the code used to compose the constants. For example,
5552 A/C1/C2 is A/(C1 * C2), so if CODE == DIV, we want MULT. */
5555 = (code == MULT || code == DIV || code == UDIV ? MULT
5556 : is_shift || code == PLUS || code == MINUS ? PLUS : code);
5558 new_const = simplify_binary_operation (associate_code, mode,
5559 const_arg1, inner_const);
5564 /* If we are associating shift operations, don't let this
5565 produce a shift of the size of the object or larger.
5566 This could occur when we follow a sign-extend by a right
5567 shift on a machine that does a sign-extend as a pair
5570 if (is_shift && GET_CODE (new_const) == CONST_INT
5571 && INTVAL (new_const) >= GET_MODE_BITSIZE (mode))
5573 /* As an exception, we can turn an ASHIFTRT of this
5574 form into a shift of the number of bits - 1. */
5575 if (code == ASHIFTRT)
5576 new_const = GEN_INT (GET_MODE_BITSIZE (mode) - 1);
5581 y = copy_rtx (XEXP (y, 0));
5583 /* If Y contains our first operand (the most common way this
5584 can happen is if Y is a MEM), we would do into an infinite
5585 loop if we tried to fold it. So don't in that case. */
5587 if (! reg_mentioned_p (folded_arg0, y))
5588 y = fold_rtx (y, insn);
5590 return cse_gen_binary (code, mode, y, new_const);
5594 new = simplify_binary_operation (code, mode,
5595 const_arg0 ? const_arg0 : folded_arg0,
5596 const_arg1 ? const_arg1 : folded_arg1);
5600 /* (lo_sum (high X) X) is simply X. */
5601 if (code == LO_SUM && const_arg0 != 0
5602 && GET_CODE (const_arg0) == HIGH
5603 && rtx_equal_p (XEXP (const_arg0, 0), const_arg1))
5609 new = simplify_ternary_operation (code, mode, mode_arg0,
5610 const_arg0 ? const_arg0 : folded_arg0,
5611 const_arg1 ? const_arg1 : folded_arg1,
5612 const_arg2 ? const_arg2 : XEXP (x, 2));
5616 return new ? new : x;
5619 /* Return a constant value currently equivalent to X.
5620 Return 0 if we don't know one. */
5626 if (GET_CODE (x) == REG
5627 && REGNO_QTY_VALID_P (REGNO (x))
5628 && qty_const[reg_qty[REGNO (x)]])
5629 x = gen_lowpart_if_possible (GET_MODE (x), qty_const[reg_qty[REGNO (x)]]);
5631 if (x != 0 && CONSTANT_P (x))
5634 /* If X is a MEM, try to fold it outside the context of any insn to see if
5635 it might be equivalent to a constant. That handles the case where it
5636 is a constant-pool reference. Then try to look it up in the hash table
5637 in case it is something whose value we have seen before. */
5639 if (GET_CODE (x) == MEM)
5641 struct table_elt *elt;
5643 x = fold_rtx (x, NULL_RTX);
5647 elt = lookup (x, safe_hash (x, GET_MODE (x)) % NBUCKETS, GET_MODE (x));
5651 for (elt = elt->first_same_value; elt; elt = elt->next_same_value)
5652 if (elt->is_const && CONSTANT_P (elt->exp))
5659 /* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a fixed-point
5660 number, return an rtx (MEM, SUBREG, or CONST_INT) that refers to the
5661 least-significant part of X.
5662 MODE specifies how big a part of X to return.
5664 If the requested operation cannot be done, 0 is returned.
5666 This is similar to gen_lowpart in emit-rtl.c. */
5669 gen_lowpart_if_possible (mode, x)
5670 enum machine_mode mode;
5673 rtx result = gen_lowpart_common (mode, x);
5677 else if (GET_CODE (x) == MEM)
5679 /* This is the only other case we handle. */
5680 register int offset = 0;
5683 if (WORDS_BIG_ENDIAN)
5684 offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
5685 - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
5686 if (BYTES_BIG_ENDIAN)
5687 /* Adjust the address so that the address-after-the-data is
5689 offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
5690 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
5691 new = gen_rtx (MEM, mode, plus_constant (XEXP (x, 0), offset));
5692 if (! memory_address_p (mode, XEXP (new, 0)))
5694 MEM_VOLATILE_P (new) = MEM_VOLATILE_P (x);
5695 RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (x);
5696 MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (x);
5703 /* Given INSN, a jump insn, TAKEN indicates if we are following the "taken"
5704 branch. It will be zero if not.
5706 In certain cases, this can cause us to add an equivalence. For example,
5707 if we are following the taken case of
5709 we can add the fact that `i' and '2' are now equivalent.
5711 In any case, we can record that this comparison was passed. If the same
5712 comparison is seen later, we will know its value. */
5715 record_jump_equiv (insn, taken)
5719 int cond_known_true;
5721 enum machine_mode mode, mode0, mode1;
5722 int reversed_nonequality = 0;
5725 /* Ensure this is the right kind of insn. */
5726 if (! condjump_p (insn) || simplejump_p (insn))
5729 /* See if this jump condition is known true or false. */
5731 cond_known_true = (XEXP (SET_SRC (PATTERN (insn)), 2) == pc_rtx);
5733 cond_known_true = (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx);
5735 /* Get the type of comparison being done and the operands being compared.
5736 If we had to reverse a non-equality condition, record that fact so we
5737 know that it isn't valid for floating-point. */
5738 code = GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 0));
5739 op0 = fold_rtx (XEXP (XEXP (SET_SRC (PATTERN (insn)), 0), 0), insn);
5740 op1 = fold_rtx (XEXP (XEXP (SET_SRC (PATTERN (insn)), 0), 1), insn);
5742 code = find_comparison_args (code, &op0, &op1, &mode0, &mode1);
5743 if (! cond_known_true)
5745 reversed_nonequality = (code != EQ && code != NE);
5746 code = reverse_condition (code);
5749 /* The mode is the mode of the non-constant. */
5751 if (mode1 != VOIDmode)
5754 record_jump_cond (code, mode, op0, op1, reversed_nonequality);
5757 /* We know that comparison CODE applied to OP0 and OP1 in MODE is true.
5758 REVERSED_NONEQUALITY is nonzero if CODE had to be swapped.
5759 Make any useful entries we can with that information. Called from
5760 above function and called recursively. */
5763 record_jump_cond (code, mode, op0, op1, reversed_nonequality)
5765 enum machine_mode mode;
5767 int reversed_nonequality;
5769 unsigned op0_hash, op1_hash;
5770 int op0_in_memory, op0_in_struct, op1_in_memory, op1_in_struct;
5771 struct table_elt *op0_elt, *op1_elt;
5773 /* If OP0 and OP1 are known equal, and either is a paradoxical SUBREG,
5774 we know that they are also equal in the smaller mode (this is also
5775 true for all smaller modes whether or not there is a SUBREG, but
5776 is not worth testing for with no SUBREG. */
5778 /* Note that GET_MODE (op0) may not equal MODE. */
5779 if (code == EQ && GET_CODE (op0) == SUBREG
5780 && (GET_MODE_SIZE (GET_MODE (op0))
5781 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))
5783 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
5784 rtx tem = gen_lowpart_if_possible (inner_mode, op1);
5786 record_jump_cond (code, mode, SUBREG_REG (op0),
5787 tem ? tem : gen_rtx (SUBREG, inner_mode, op1, 0),
5788 reversed_nonequality);
5791 if (code == EQ && GET_CODE (op1) == SUBREG
5792 && (GET_MODE_SIZE (GET_MODE (op1))
5793 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (op1)))))
5795 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1));
5796 rtx tem = gen_lowpart_if_possible (inner_mode, op0);
5798 record_jump_cond (code, mode, SUBREG_REG (op1),
5799 tem ? tem : gen_rtx (SUBREG, inner_mode, op0, 0),
5800 reversed_nonequality);
5803 /* Similarly, if this is an NE comparison, and either is a SUBREG
5804 making a smaller mode, we know the whole thing is also NE. */
5806 /* Note that GET_MODE (op0) may not equal MODE;
5807 if we test MODE instead, we can get an infinite recursion
5808 alternating between two modes each wider than MODE. */
5810 if (code == NE && GET_CODE (op0) == SUBREG
5811 && subreg_lowpart_p (op0)
5812 && (GET_MODE_SIZE (GET_MODE (op0))
5813 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0)))))
5815 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
5816 rtx tem = gen_lowpart_if_possible (inner_mode, op1);
5818 record_jump_cond (code, mode, SUBREG_REG (op0),
5819 tem ? tem : gen_rtx (SUBREG, inner_mode, op1, 0),
5820 reversed_nonequality);
5823 if (code == NE && GET_CODE (op1) == SUBREG
5824 && subreg_lowpart_p (op1)
5825 && (GET_MODE_SIZE (GET_MODE (op1))
5826 < GET_MODE_SIZE (GET_MODE (SUBREG_REG (op1)))))
5828 enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1));
5829 rtx tem = gen_lowpart_if_possible (inner_mode, op0);
5831 record_jump_cond (code, mode, SUBREG_REG (op1),
5832 tem ? tem : gen_rtx (SUBREG, inner_mode, op0, 0),
5833 reversed_nonequality);
5836 /* Hash both operands. */
5839 hash_arg_in_memory = 0;
5840 hash_arg_in_struct = 0;
5841 op0_hash = HASH (op0, mode);
5842 op0_in_memory = hash_arg_in_memory;
5843 op0_in_struct = hash_arg_in_struct;
5849 hash_arg_in_memory = 0;
5850 hash_arg_in_struct = 0;
5851 op1_hash = HASH (op1, mode);
5852 op1_in_memory = hash_arg_in_memory;
5853 op1_in_struct = hash_arg_in_struct;
5858 /* Look up both operands. */
5859 op0_elt = lookup (op0, op0_hash, mode);
5860 op1_elt = lookup (op1, op1_hash, mode);
5862 /* If both operands are already equivalent or if they are not in the
5863 table but are identical, do nothing. */
5864 if ((op0_elt != 0 && op1_elt != 0
5865 && op0_elt->first_same_value == op1_elt->first_same_value)
5866 || op0 == op1 || rtx_equal_p (op0, op1))
5869 /* If we aren't setting two things equal all we can do is save this
5870 comparison. Similarly if this is floating-point. In the latter
5871 case, OP1 might be zero and both -0.0 and 0.0 are equal to it.
5872 If we record the equality, we might inadvertently delete code
5873 whose intent was to change -0 to +0. */
5875 if (code != EQ || FLOAT_MODE_P (GET_MODE (op0)))
5877 /* If we reversed a floating-point comparison, if OP0 is not a
5878 register, or if OP1 is neither a register or constant, we can't
5881 if (GET_CODE (op1) != REG)
5882 op1 = equiv_constant (op1);
5884 if ((reversed_nonequality && FLOAT_MODE_P (mode))
5885 || GET_CODE (op0) != REG || op1 == 0)
5888 /* Put OP0 in the hash table if it isn't already. This gives it a
5889 new quantity number. */
5892 if (insert_regs (op0, NULL_PTR, 0))
5894 rehash_using_reg (op0);
5895 op0_hash = HASH (op0, mode);
5897 /* If OP0 is contained in OP1, this changes its hash code
5898 as well. Faster to rehash than to check, except
5899 for the simple case of a constant. */
5900 if (! CONSTANT_P (op1))
5901 op1_hash = HASH (op1,mode);
5904 op0_elt = insert (op0, NULL_PTR, op0_hash, mode);
5905 op0_elt->in_memory = op0_in_memory;
5906 op0_elt->in_struct = op0_in_struct;
5909 qty_comparison_code[reg_qty[REGNO (op0)]] = code;
5910 if (GET_CODE (op1) == REG)
5912 /* Look it up again--in case op0 and op1 are the same. */
5913 op1_elt = lookup (op1, op1_hash, mode);
5915 /* Put OP1 in the hash table so it gets a new quantity number. */
5918 if (insert_regs (op1, NULL_PTR, 0))
5920 rehash_using_reg (op1);
5921 op1_hash = HASH (op1, mode);
5924 op1_elt = insert (op1, NULL_PTR, op1_hash, mode);
5925 op1_elt->in_memory = op1_in_memory;
5926 op1_elt->in_struct = op1_in_struct;
5929 qty_comparison_qty[reg_qty[REGNO (op0)]] = reg_qty[REGNO (op1)];
5930 qty_comparison_const[reg_qty[REGNO (op0)]] = 0;
5934 qty_comparison_qty[reg_qty[REGNO (op0)]] = -1;
5935 qty_comparison_const[reg_qty[REGNO (op0)]] = op1;
5941 /* If either side is still missing an equivalence, make it now,
5942 then merge the equivalences. */
5946 if (insert_regs (op0, NULL_PTR, 0))
5948 rehash_using_reg (op0);
5949 op0_hash = HASH (op0, mode);
5952 op0_elt = insert (op0, NULL_PTR, op0_hash, mode);
5953 op0_elt->in_memory = op0_in_memory;
5954 op0_elt->in_struct = op0_in_struct;
5959 if (insert_regs (op1, NULL_PTR, 0))
5961 rehash_using_reg (op1);
5962 op1_hash = HASH (op1, mode);
5965 op1_elt = insert (op1, NULL_PTR, op1_hash, mode);
5966 op1_elt->in_memory = op1_in_memory;
5967 op1_elt->in_struct = op1_in_struct;
5970 merge_equiv_classes (op0_elt, op1_elt);
5971 last_jump_equiv_class = op0_elt;
5974 /* CSE processing for one instruction.
5975 First simplify sources and addresses of all assignments
5976 in the instruction, using previously-computed equivalents values.
5977 Then install the new sources and destinations in the table
5978 of available values.
5980 If IN_LIBCALL_BLOCK is nonzero, don't record any equivalence made in
5983 /* Data on one SET contained in the instruction. */
5987 /* The SET rtx itself. */
5989 /* The SET_SRC of the rtx (the original value, if it is changing). */
5991 /* The hash-table element for the SET_SRC of the SET. */
5992 struct table_elt *src_elt;
5993 /* Hash value for the SET_SRC. */
5995 /* Hash value for the SET_DEST. */
5997 /* The SET_DEST, with SUBREG, etc., stripped. */
5999 /* Place where the pointer to the INNER_DEST was found. */
6000 rtx *inner_dest_loc;
6001 /* Nonzero if the SET_SRC is in memory. */
6003 /* Nonzero if the SET_SRC is in a structure. */
6005 /* Nonzero if the SET_SRC contains something
6006 whose value cannot be predicted and understood. */
6008 /* Original machine mode, in case it becomes a CONST_INT. */
6009 enum machine_mode mode;
6010 /* A constant equivalent for SET_SRC, if any. */
6012 /* Hash value of constant equivalent for SET_SRC. */
6013 unsigned src_const_hash;
6014 /* Table entry for constant equivalent for SET_SRC, if any. */
6015 struct table_elt *src_const_elt;
6019 cse_insn (insn, in_libcall_block)
6021 int in_libcall_block;
6023 register rtx x = PATTERN (insn);
6026 register int n_sets = 0;
6028 /* Records what this insn does to set CC0. */
6029 rtx this_insn_cc0 = 0;
6030 enum machine_mode this_insn_cc0_mode;
6031 struct write_data writes_memory;
6032 static struct write_data init = {0, 0, 0, 0};
6035 struct table_elt *src_eqv_elt = 0;
6036 int src_eqv_volatile;
6037 int src_eqv_in_memory;
6038 int src_eqv_in_struct;
6039 unsigned src_eqv_hash;
6044 writes_memory = init;
6046 /* Find all the SETs and CLOBBERs in this instruction.
6047 Record all the SETs in the array `set' and count them.
6048 Also determine whether there is a CLOBBER that invalidates
6049 all memory references, or all references at varying addresses. */
6051 if (GET_CODE (insn) == CALL_INSN)
6053 for (tem = CALL_INSN_FUNCTION_USAGE (insn); tem; tem = XEXP (tem, 1))
6054 if (GET_CODE (XEXP (tem, 0)) == CLOBBER)
6055 invalidate (SET_DEST (XEXP (tem, 0)), VOIDmode);
6058 if (GET_CODE (x) == SET)
6060 sets = (struct set *) alloca (sizeof (struct set));
6063 /* Ignore SETs that are unconditional jumps.
6064 They never need cse processing, so this does not hurt.
6065 The reason is not efficiency but rather
6066 so that we can test at the end for instructions
6067 that have been simplified to unconditional jumps
6068 and not be misled by unchanged instructions
6069 that were unconditional jumps to begin with. */
6070 if (SET_DEST (x) == pc_rtx
6071 && GET_CODE (SET_SRC (x)) == LABEL_REF)
6074 /* Don't count call-insns, (set (reg 0) (call ...)), as a set.
6075 The hard function value register is used only once, to copy to
6076 someplace else, so it isn't worth cse'ing (and on 80386 is unsafe)!
6077 Ensure we invalidate the destination register. On the 80386 no
6078 other code would invalidate it since it is a fixed_reg.
6079 We need not check the return of apply_change_group; see canon_reg. */
6081 else if (GET_CODE (SET_SRC (x)) == CALL)
6083 canon_reg (SET_SRC (x), insn);
6084 apply_change_group ();
6085 fold_rtx (SET_SRC (x), insn);
6086 invalidate (SET_DEST (x), VOIDmode);
6091 else if (GET_CODE (x) == PARALLEL)
6093 register int lim = XVECLEN (x, 0);
6095 sets = (struct set *) alloca (lim * sizeof (struct set));
6097 /* Find all regs explicitly clobbered in this insn,
6098 and ensure they are not replaced with any other regs
6099 elsewhere in this insn.
6100 When a reg that is clobbered is also used for input,
6101 we should presume that that is for a reason,
6102 and we should not substitute some other register
6103 which is not supposed to be clobbered.
6104 Therefore, this loop cannot be merged into the one below
6105 because a CALL may precede a CLOBBER and refer to the
6106 value clobbered. We must not let a canonicalization do
6107 anything in that case. */
6108 for (i = 0; i < lim; i++)
6110 register rtx y = XVECEXP (x, 0, i);
6111 if (GET_CODE (y) == CLOBBER)
6113 rtx clobbered = XEXP (y, 0);
6115 if (GET_CODE (clobbered) == REG
6116 || GET_CODE (clobbered) == SUBREG)
6117 invalidate (clobbered, VOIDmode);
6118 else if (GET_CODE (clobbered) == STRICT_LOW_PART
6119 || GET_CODE (clobbered) == ZERO_EXTRACT)
6120 invalidate (XEXP (clobbered, 0), GET_MODE (clobbered));
6124 for (i = 0; i < lim; i++)
6126 register rtx y = XVECEXP (x, 0, i);
6127 if (GET_CODE (y) == SET)
6129 /* As above, we ignore unconditional jumps and call-insns and
6130 ignore the result of apply_change_group. */
6131 if (GET_CODE (SET_SRC (y)) == CALL)
6133 canon_reg (SET_SRC (y), insn);
6134 apply_change_group ();
6135 fold_rtx (SET_SRC (y), insn);
6136 invalidate (SET_DEST (y), VOIDmode);
6138 else if (SET_DEST (y) == pc_rtx
6139 && GET_CODE (SET_SRC (y)) == LABEL_REF)
6142 sets[n_sets++].rtl = y;
6144 else if (GET_CODE (y) == CLOBBER)
6146 /* If we clobber memory, take note of that,
6147 and canon the address.
6148 This does nothing when a register is clobbered
6149 because we have already invalidated the reg. */
6150 if (GET_CODE (XEXP (y, 0)) == MEM)
6152 canon_reg (XEXP (y, 0), NULL_RTX);
6153 note_mem_written (XEXP (y, 0), &writes_memory);
6156 else if (GET_CODE (y) == USE
6157 && ! (GET_CODE (XEXP (y, 0)) == REG
6158 && REGNO (XEXP (y, 0)) < FIRST_PSEUDO_REGISTER))
6159 canon_reg (y, NULL_RTX);
6160 else if (GET_CODE (y) == CALL)
6162 /* The result of apply_change_group can be ignored; see
6164 canon_reg (y, insn);
6165 apply_change_group ();
6170 else if (GET_CODE (x) == CLOBBER)
6172 if (GET_CODE (XEXP (x, 0)) == MEM)
6174 canon_reg (XEXP (x, 0), NULL_RTX);
6175 note_mem_written (XEXP (x, 0), &writes_memory);
6179 /* Canonicalize a USE of a pseudo register or memory location. */
6180 else if (GET_CODE (x) == USE
6181 && ! (GET_CODE (XEXP (x, 0)) == REG
6182 && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER))
6183 canon_reg (XEXP (x, 0), NULL_RTX);
6184 else if (GET_CODE (x) == CALL)
6186 /* The result of apply_change_group can be ignored; see canon_reg. */
6187 canon_reg (x, insn);
6188 apply_change_group ();
6192 /* Store the equivalent value in SRC_EQV, if different, or if the DEST
6193 is a STRICT_LOW_PART. The latter condition is necessary because SRC_EQV
6194 is handled specially for this case, and if it isn't set, then there will
6195 be no equivalence for the destinatation. */
6196 if (n_sets == 1 && REG_NOTES (insn) != 0
6197 && (tem = find_reg_note (insn, REG_EQUAL, NULL_RTX)) != 0
6198 && (! rtx_equal_p (XEXP (tem, 0), SET_SRC (sets[0].rtl))
6199 || GET_CODE (SET_DEST (sets[0].rtl)) == STRICT_LOW_PART))
6200 src_eqv = canon_reg (XEXP (tem, 0), NULL_RTX);
6202 /* Canonicalize sources and addresses of destinations.
6203 We do this in a separate pass to avoid problems when a MATCH_DUP is
6204 present in the insn pattern. In that case, we want to ensure that
6205 we don't break the duplicate nature of the pattern. So we will replace
6206 both operands at the same time. Otherwise, we would fail to find an
6207 equivalent substitution in the loop calling validate_change below.
6209 We used to suppress canonicalization of DEST if it appears in SRC,
6210 but we don't do this any more. */
6212 for (i = 0; i < n_sets; i++)
6214 rtx dest = SET_DEST (sets[i].rtl);
6215 rtx src = SET_SRC (sets[i].rtl);
6216 rtx new = canon_reg (src, insn);
6218 if ((GET_CODE (new) == REG && GET_CODE (src) == REG
6219 && ((REGNO (new) < FIRST_PSEUDO_REGISTER)
6220 != (REGNO (src) < FIRST_PSEUDO_REGISTER)))
6221 || insn_n_dups[recog_memoized (insn)] > 0)
6222 validate_change (insn, &SET_SRC (sets[i].rtl), new, 1);
6224 SET_SRC (sets[i].rtl) = new;
6226 if (GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == SIGN_EXTRACT)
6228 validate_change (insn, &XEXP (dest, 1),
6229 canon_reg (XEXP (dest, 1), insn), 1);
6230 validate_change (insn, &XEXP (dest, 2),
6231 canon_reg (XEXP (dest, 2), insn), 1);
6234 while (GET_CODE (dest) == SUBREG || GET_CODE (dest) == STRICT_LOW_PART
6235 || GET_CODE (dest) == ZERO_EXTRACT
6236 || GET_CODE (dest) == SIGN_EXTRACT)
6237 dest = XEXP (dest, 0);
6239 if (GET_CODE (dest) == MEM)
6240 canon_reg (dest, insn);
6243 /* Now that we have done all the replacements, we can apply the change
6244 group and see if they all work. Note that this will cause some
6245 canonicalizations that would have worked individually not to be applied
6246 because some other canonicalization didn't work, but this should not
6249 The result of apply_change_group can be ignored; see canon_reg. */
6251 apply_change_group ();
6253 /* Set sets[i].src_elt to the class each source belongs to.
6254 Detect assignments from or to volatile things
6255 and set set[i] to zero so they will be ignored
6256 in the rest of this function.
6258 Nothing in this loop changes the hash table or the register chains. */
6260 for (i = 0; i < n_sets; i++)
6262 register rtx src, dest;
6263 register rtx src_folded;
6264 register struct table_elt *elt = 0, *p;
6265 enum machine_mode mode;
6268 rtx src_related = 0;
6269 struct table_elt *src_const_elt = 0;
6270 int src_cost = 10000, src_eqv_cost = 10000, src_folded_cost = 10000;
6271 int src_related_cost = 10000, src_elt_cost = 10000;
6272 /* Set non-zero if we need to call force_const_mem on with the
6273 contents of src_folded before using it. */
6274 int src_folded_force_flag = 0;
6276 dest = SET_DEST (sets[i].rtl);
6277 src = SET_SRC (sets[i].rtl);
6279 /* If SRC is a constant that has no machine mode,
6280 hash it with the destination's machine mode.
6281 This way we can keep different modes separate. */
6283 mode = GET_MODE (src) == VOIDmode ? GET_MODE (dest) : GET_MODE (src);
6284 sets[i].mode = mode;
6288 enum machine_mode eqvmode = mode;
6289 if (GET_CODE (dest) == STRICT_LOW_PART)
6290 eqvmode = GET_MODE (SUBREG_REG (XEXP (dest, 0)));
6292 hash_arg_in_memory = 0;
6293 hash_arg_in_struct = 0;
6294 src_eqv = fold_rtx (src_eqv, insn);
6295 src_eqv_hash = HASH (src_eqv, eqvmode);
6297 /* Find the equivalence class for the equivalent expression. */
6300 src_eqv_elt = lookup (src_eqv, src_eqv_hash, eqvmode);
6302 src_eqv_volatile = do_not_record;
6303 src_eqv_in_memory = hash_arg_in_memory;
6304 src_eqv_in_struct = hash_arg_in_struct;
6307 /* If this is a STRICT_LOW_PART assignment, src_eqv corresponds to the
6308 value of the INNER register, not the destination. So it is not
6309 a valid substitution for the source. But save it for later. */
6310 if (GET_CODE (dest) == STRICT_LOW_PART)
6313 src_eqv_here = src_eqv;
6315 /* Simplify and foldable subexpressions in SRC. Then get the fully-
6316 simplified result, which may not necessarily be valid. */
6317 src_folded = fold_rtx (src, insn);
6319 /* If storing a constant in a bitfield, pre-truncate the constant
6320 so we will be able to record it later. */
6321 if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT
6322 || GET_CODE (SET_DEST (sets[i].rtl)) == SIGN_EXTRACT)
6324 rtx width = XEXP (SET_DEST (sets[i].rtl), 1);
6326 if (GET_CODE (src) == CONST_INT
6327 && GET_CODE (width) == CONST_INT
6328 && INTVAL (width) < HOST_BITS_PER_WIDE_INT
6329 && (INTVAL (src) & ((HOST_WIDE_INT) (-1) << INTVAL (width))))
6331 = GEN_INT (INTVAL (src) & (((HOST_WIDE_INT) 1
6332 << INTVAL (width)) - 1));
6335 /* Compute SRC's hash code, and also notice if it
6336 should not be recorded at all. In that case,
6337 prevent any further processing of this assignment. */
6339 hash_arg_in_memory = 0;
6340 hash_arg_in_struct = 0;
6343 sets[i].src_hash = HASH (src, mode);
6344 sets[i].src_volatile = do_not_record;
6345 sets[i].src_in_memory = hash_arg_in_memory;
6346 sets[i].src_in_struct = hash_arg_in_struct;
6349 /* It is no longer clear why we used to do this, but it doesn't
6350 appear to still be needed. So let's try without it since this
6351 code hurts cse'ing widened ops. */
6352 /* If source is a perverse subreg (such as QI treated as an SI),
6353 treat it as volatile. It may do the work of an SI in one context
6354 where the extra bits are not being used, but cannot replace an SI
6356 if (GET_CODE (src) == SUBREG
6357 && (GET_MODE_SIZE (GET_MODE (src))
6358 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (src)))))
6359 sets[i].src_volatile = 1;
6362 /* Locate all possible equivalent forms for SRC. Try to replace
6363 SRC in the insn with each cheaper equivalent.
6365 We have the following types of equivalents: SRC itself, a folded
6366 version, a value given in a REG_EQUAL note, or a value related
6369 Each of these equivalents may be part of an additional class
6370 of equivalents (if more than one is in the table, they must be in
6371 the same class; we check for this).
6373 If the source is volatile, we don't do any table lookups.
6375 We note any constant equivalent for possible later use in a
6378 if (!sets[i].src_volatile)
6379 elt = lookup (src, sets[i].src_hash, mode);
6381 sets[i].src_elt = elt;
6383 if (elt && src_eqv_here && src_eqv_elt)
6385 if (elt->first_same_value != src_eqv_elt->first_same_value)
6387 /* The REG_EQUAL is indicating that two formerly distinct
6388 classes are now equivalent. So merge them. */
6389 merge_equiv_classes (elt, src_eqv_elt);
6390 src_eqv_hash = HASH (src_eqv, elt->mode);
6391 src_eqv_elt = lookup (src_eqv, src_eqv_hash, elt->mode);
6397 else if (src_eqv_elt)
6400 /* Try to find a constant somewhere and record it in `src_const'.
6401 Record its table element, if any, in `src_const_elt'. Look in
6402 any known equivalences first. (If the constant is not in the
6403 table, also set `sets[i].src_const_hash'). */
6405 for (p = elt->first_same_value; p; p = p->next_same_value)
6409 src_const_elt = elt;
6414 && (CONSTANT_P (src_folded)
6415 /* Consider (minus (label_ref L1) (label_ref L2)) as
6416 "constant" here so we will record it. This allows us
6417 to fold switch statements when an ADDR_DIFF_VEC is used. */
6418 || (GET_CODE (src_folded) == MINUS
6419 && GET_CODE (XEXP (src_folded, 0)) == LABEL_REF
6420 && GET_CODE (XEXP (src_folded, 1)) == LABEL_REF)))
6421 src_const = src_folded, src_const_elt = elt;
6422 else if (src_const == 0 && src_eqv_here && CONSTANT_P (src_eqv_here))
6423 src_const = src_eqv_here, src_const_elt = src_eqv_elt;
6425 /* If we don't know if the constant is in the table, get its
6426 hash code and look it up. */
6427 if (src_const && src_const_elt == 0)
6429 sets[i].src_const_hash = HASH (src_const, mode);
6430 src_const_elt = lookup (src_const, sets[i].src_const_hash, mode);
6433 sets[i].src_const = src_const;
6434 sets[i].src_const_elt = src_const_elt;
6436 /* If the constant and our source are both in the table, mark them as
6437 equivalent. Otherwise, if a constant is in the table but the source
6438 isn't, set ELT to it. */
6439 if (src_const_elt && elt
6440 && src_const_elt->first_same_value != elt->first_same_value)
6441 merge_equiv_classes (elt, src_const_elt);
6442 else if (src_const_elt && elt == 0)
6443 elt = src_const_elt;
6445 /* See if there is a register linearly related to a constant
6446 equivalent of SRC. */
6448 && (GET_CODE (src_const) == CONST
6449 || (src_const_elt && src_const_elt->related_value != 0)))
6451 src_related = use_related_value (src_const, src_const_elt);
6454 struct table_elt *src_related_elt
6455 = lookup (src_related, HASH (src_related, mode), mode);
6456 if (src_related_elt && elt)
6458 if (elt->first_same_value
6459 != src_related_elt->first_same_value)
6460 /* This can occur when we previously saw a CONST
6461 involving a SYMBOL_REF and then see the SYMBOL_REF
6462 twice. Merge the involved classes. */
6463 merge_equiv_classes (elt, src_related_elt);
6466 src_related_elt = 0;
6468 else if (src_related_elt && elt == 0)
6469 elt = src_related_elt;
6473 /* See if we have a CONST_INT that is already in a register in a
6476 if (src_const && src_related == 0 && GET_CODE (src_const) == CONST_INT
6477 && GET_MODE_CLASS (mode) == MODE_INT
6478 && GET_MODE_BITSIZE (mode) < BITS_PER_WORD)
6480 enum machine_mode wider_mode;
6482 for (wider_mode = GET_MODE_WIDER_MODE (mode);
6483 GET_MODE_BITSIZE (wider_mode) <= BITS_PER_WORD
6484 && src_related == 0;
6485 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
6487 struct table_elt *const_elt
6488 = lookup (src_const, HASH (src_const, wider_mode), wider_mode);
6493 for (const_elt = const_elt->first_same_value;
6494 const_elt; const_elt = const_elt->next_same_value)
6495 if (GET_CODE (const_elt->exp) == REG)
6497 src_related = gen_lowpart_if_possible (mode,
6504 /* Another possibility is that we have an AND with a constant in
6505 a mode narrower than a word. If so, it might have been generated
6506 as part of an "if" which would narrow the AND. If we already
6507 have done the AND in a wider mode, we can use a SUBREG of that
6510 if (flag_expensive_optimizations && ! src_related
6511 && GET_CODE (src) == AND && GET_CODE (XEXP (src, 1)) == CONST_INT
6512 && GET_MODE_SIZE (mode) < UNITS_PER_WORD)
6514 enum machine_mode tmode;
6515 rtx new_and = gen_rtx (AND, VOIDmode, NULL_RTX, XEXP (src, 1));
6517 for (tmode = GET_MODE_WIDER_MODE (mode);
6518 GET_MODE_SIZE (tmode) <= UNITS_PER_WORD;
6519 tmode = GET_MODE_WIDER_MODE (tmode))
6521 rtx inner = gen_lowpart_if_possible (tmode, XEXP (src, 0));
6522 struct table_elt *larger_elt;
6526 PUT_MODE (new_and, tmode);
6527 XEXP (new_and, 0) = inner;
6528 larger_elt = lookup (new_and, HASH (new_and, tmode), tmode);
6529 if (larger_elt == 0)
6532 for (larger_elt = larger_elt->first_same_value;
6533 larger_elt; larger_elt = larger_elt->next_same_value)
6534 if (GET_CODE (larger_elt->exp) == REG)
6537 = gen_lowpart_if_possible (mode, larger_elt->exp);
6547 #ifdef LOAD_EXTEND_OP
6548 /* See if a MEM has already been loaded with a widening operation;
6549 if it has, we can use a subreg of that. Many CISC machines
6550 also have such operations, but this is only likely to be
6551 beneficial these machines. */
6553 if (flag_expensive_optimizations && src_related == 0
6554 && (GET_MODE_SIZE (mode) < UNITS_PER_WORD)
6555 && GET_MODE_CLASS (mode) == MODE_INT
6556 && GET_CODE (src) == MEM && ! do_not_record
6557 && LOAD_EXTEND_OP (mode) != NIL)
6559 enum machine_mode tmode;
6561 /* Set what we are trying to extend and the operation it might
6562 have been extended with. */
6563 PUT_CODE (memory_extend_rtx, LOAD_EXTEND_OP (mode));
6564 XEXP (memory_extend_rtx, 0) = src;
6566 for (tmode = GET_MODE_WIDER_MODE (mode);
6567 GET_MODE_SIZE (tmode) <= UNITS_PER_WORD;
6568 tmode = GET_MODE_WIDER_MODE (tmode))
6570 struct table_elt *larger_elt;
6572 PUT_MODE (memory_extend_rtx, tmode);
6573 larger_elt = lookup (memory_extend_rtx,
6574 HASH (memory_extend_rtx, tmode), tmode);
6575 if (larger_elt == 0)
6578 for (larger_elt = larger_elt->first_same_value;
6579 larger_elt; larger_elt = larger_elt->next_same_value)
6580 if (GET_CODE (larger_elt->exp) == REG)
6582 src_related = gen_lowpart_if_possible (mode,
6591 #endif /* LOAD_EXTEND_OP */
6593 if (src == src_folded)
6596 /* At this point, ELT, if non-zero, points to a class of expressions
6597 equivalent to the source of this SET and SRC, SRC_EQV, SRC_FOLDED,
6598 and SRC_RELATED, if non-zero, each contain additional equivalent
6599 expressions. Prune these latter expressions by deleting expressions
6600 already in the equivalence class.
6602 Check for an equivalent identical to the destination. If found,
6603 this is the preferred equivalent since it will likely lead to
6604 elimination of the insn. Indicate this by placing it in
6607 if (elt) elt = elt->first_same_value;
6608 for (p = elt; p; p = p->next_same_value)
6610 enum rtx_code code = GET_CODE (p->exp);
6612 /* If the expression is not valid, ignore it. Then we do not
6613 have to check for validity below. In most cases, we can use
6614 `rtx_equal_p', since canonicalization has already been done. */
6615 if (code != REG && ! exp_equiv_p (p->exp, p->exp, 1, 0))
6618 if (src && GET_CODE (src) == code && rtx_equal_p (src, p->exp))
6620 else if (src_folded && GET_CODE (src_folded) == code
6621 && rtx_equal_p (src_folded, p->exp))
6623 else if (src_eqv_here && GET_CODE (src_eqv_here) == code
6624 && rtx_equal_p (src_eqv_here, p->exp))
6626 else if (src_related && GET_CODE (src_related) == code
6627 && rtx_equal_p (src_related, p->exp))
6630 /* This is the same as the destination of the insns, we want
6631 to prefer it. Copy it to src_related. The code below will
6632 then give it a negative cost. */
6633 if (GET_CODE (dest) == code && rtx_equal_p (p->exp, dest))
6638 /* Find the cheapest valid equivalent, trying all the available
6639 possibilities. Prefer items not in the hash table to ones
6640 that are when they are equal cost. Note that we can never
6641 worsen an insn as the current contents will also succeed.
6642 If we find an equivalent identical to the destination, use it as best,
6643 since this insn will probably be eliminated in that case. */
6646 if (rtx_equal_p (src, dest))
6649 src_cost = COST (src);
6654 if (rtx_equal_p (src_eqv_here, dest))
6657 src_eqv_cost = COST (src_eqv_here);
6662 if (rtx_equal_p (src_folded, dest))
6663 src_folded_cost = -1;
6665 src_folded_cost = COST (src_folded);
6670 if (rtx_equal_p (src_related, dest))
6671 src_related_cost = -1;
6673 src_related_cost = COST (src_related);
6676 /* If this was an indirect jump insn, a known label will really be
6677 cheaper even though it looks more expensive. */
6678 if (dest == pc_rtx && src_const && GET_CODE (src_const) == LABEL_REF)
6679 src_folded = src_const, src_folded_cost = -1;
6681 /* Terminate loop when replacement made. This must terminate since
6682 the current contents will be tested and will always be valid. */
6687 /* Skip invalid entries. */
6688 while (elt && GET_CODE (elt->exp) != REG
6689 && ! exp_equiv_p (elt->exp, elt->exp, 1, 0))
6690 elt = elt->next_same_value;
6692 if (elt) src_elt_cost = elt->cost;
6694 /* Find cheapest and skip it for the next time. For items
6695 of equal cost, use this order:
6696 src_folded, src, src_eqv, src_related and hash table entry. */
6697 if (src_folded_cost <= src_cost
6698 && src_folded_cost <= src_eqv_cost
6699 && src_folded_cost <= src_related_cost
6700 && src_folded_cost <= src_elt_cost)
6702 trial = src_folded, src_folded_cost = 10000;
6703 if (src_folded_force_flag)
6704 trial = force_const_mem (mode, trial);
6706 else if (src_cost <= src_eqv_cost
6707 && src_cost <= src_related_cost
6708 && src_cost <= src_elt_cost)
6709 trial = src, src_cost = 10000;
6710 else if (src_eqv_cost <= src_related_cost
6711 && src_eqv_cost <= src_elt_cost)
6712 trial = copy_rtx (src_eqv_here), src_eqv_cost = 10000;
6713 else if (src_related_cost <= src_elt_cost)
6714 trial = copy_rtx (src_related), src_related_cost = 10000;
6717 trial = copy_rtx (elt->exp);
6718 elt = elt->next_same_value;
6719 src_elt_cost = 10000;
6722 /* We don't normally have an insn matching (set (pc) (pc)), so
6723 check for this separately here. We will delete such an
6726 Tablejump insns contain a USE of the table, so simply replacing
6727 the operand with the constant won't match. This is simply an
6728 unconditional branch, however, and is therefore valid. Just
6729 insert the substitution here and we will delete and re-emit
6732 if (n_sets == 1 && dest == pc_rtx
6734 || (GET_CODE (trial) == LABEL_REF
6735 && ! condjump_p (insn))))
6737 /* If TRIAL is a label in front of a jump table, we are
6738 really falling through the switch (this is how casesi
6739 insns work), so we must branch around the table. */
6740 if (GET_CODE (trial) == CODE_LABEL
6741 && NEXT_INSN (trial) != 0
6742 && GET_CODE (NEXT_INSN (trial)) == JUMP_INSN
6743 && (GET_CODE (PATTERN (NEXT_INSN (trial))) == ADDR_DIFF_VEC
6744 || GET_CODE (PATTERN (NEXT_INSN (trial))) == ADDR_VEC))
6746 trial = gen_rtx (LABEL_REF, Pmode, get_label_after (trial));
6748 SET_SRC (sets[i].rtl) = trial;
6749 cse_jumps_altered = 1;
6753 /* Look for a substitution that makes a valid insn. */
6754 else if (validate_change (insn, &SET_SRC (sets[i].rtl), trial, 0))
6756 /* The result of apply_change_group can be ignored; see
6759 validate_change (insn, &SET_SRC (sets[i].rtl),
6760 canon_reg (SET_SRC (sets[i].rtl), insn),
6762 apply_change_group ();
6766 /* If we previously found constant pool entries for
6767 constants and this is a constant, try making a
6768 pool entry. Put it in src_folded unless we already have done
6769 this since that is where it likely came from. */
6771 else if (constant_pool_entries_cost
6772 && CONSTANT_P (trial)
6773 && ! (GET_CODE (trial) == CONST
6774 && GET_CODE (XEXP (trial, 0)) == TRUNCATE)
6776 || (GET_CODE (src_folded) != MEM
6777 && ! src_folded_force_flag))
6778 && GET_MODE_CLASS (mode) != MODE_CC)
6780 src_folded_force_flag = 1;
6782 src_folded_cost = constant_pool_entries_cost;
6786 src = SET_SRC (sets[i].rtl);
6788 /* In general, it is good to have a SET with SET_SRC == SET_DEST.
6789 However, there is an important exception: If both are registers
6790 that are not the head of their equivalence class, replace SET_SRC
6791 with the head of the class. If we do not do this, we will have
6792 both registers live over a portion of the basic block. This way,
6793 their lifetimes will likely abut instead of overlapping. */
6794 if (GET_CODE (dest) == REG
6795 && REGNO_QTY_VALID_P (REGNO (dest))
6796 && qty_mode[reg_qty[REGNO (dest)]] == GET_MODE (dest)
6797 && qty_first_reg[reg_qty[REGNO (dest)]] != REGNO (dest)
6798 && GET_CODE (src) == REG && REGNO (src) == REGNO (dest)
6799 /* Don't do this if the original insn had a hard reg as
6801 && (GET_CODE (sets[i].src) != REG
6802 || REGNO (sets[i].src) >= FIRST_PSEUDO_REGISTER))
6803 /* We can't call canon_reg here because it won't do anything if
6804 SRC is a hard register. */
6806 int first = qty_first_reg[reg_qty[REGNO (src)]];
6808 src = SET_SRC (sets[i].rtl)
6809 = first >= FIRST_PSEUDO_REGISTER ? regno_reg_rtx[first]
6810 : gen_rtx (REG, GET_MODE (src), first);
6812 /* If we had a constant that is cheaper than what we are now
6813 setting SRC to, use that constant. We ignored it when we
6814 thought we could make this into a no-op. */
6815 if (src_const && COST (src_const) < COST (src)
6816 && validate_change (insn, &SET_SRC (sets[i].rtl), src_const, 0))
6820 /* If we made a change, recompute SRC values. */
6821 if (src != sets[i].src)
6824 hash_arg_in_memory = 0;
6825 hash_arg_in_struct = 0;
6827 sets[i].src_hash = HASH (src, mode);
6828 sets[i].src_volatile = do_not_record;
6829 sets[i].src_in_memory = hash_arg_in_memory;
6830 sets[i].src_in_struct = hash_arg_in_struct;
6831 sets[i].src_elt = lookup (src, sets[i].src_hash, mode);
6834 /* If this is a single SET, we are setting a register, and we have an
6835 equivalent constant, we want to add a REG_NOTE. We don't want
6836 to write a REG_EQUAL note for a constant pseudo since verifying that
6837 that pseudo hasn't been eliminated is a pain. Such a note also
6838 won't help anything. */
6839 if (n_sets == 1 && src_const && GET_CODE (dest) == REG
6840 && GET_CODE (src_const) != REG)
6842 tem = find_reg_note (insn, REG_EQUAL, NULL_RTX);
6844 /* Record the actual constant value in a REG_EQUAL note, making
6845 a new one if one does not already exist. */
6847 XEXP (tem, 0) = src_const;
6849 REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_EQUAL,
6850 src_const, REG_NOTES (insn));
6852 /* If storing a constant value in a register that
6853 previously held the constant value 0,
6854 record this fact with a REG_WAS_0 note on this insn.
6856 Note that the *register* is required to have previously held 0,
6857 not just any register in the quantity and we must point to the
6858 insn that set that register to zero.
6860 Rather than track each register individually, we just see if
6861 the last set for this quantity was for this register. */
6863 if (REGNO_QTY_VALID_P (REGNO (dest))
6864 && qty_const[reg_qty[REGNO (dest)]] == const0_rtx)
6866 /* See if we previously had a REG_WAS_0 note. */
6867 rtx note = find_reg_note (insn, REG_WAS_0, NULL_RTX);
6868 rtx const_insn = qty_const_insn[reg_qty[REGNO (dest)]];
6870 if ((tem = single_set (const_insn)) != 0
6871 && rtx_equal_p (SET_DEST (tem), dest))
6874 XEXP (note, 0) = const_insn;
6876 REG_NOTES (insn) = gen_rtx (INSN_LIST, REG_WAS_0,
6877 const_insn, REG_NOTES (insn));
6882 /* Now deal with the destination. */
6884 sets[i].inner_dest_loc = &SET_DEST (sets[0].rtl);
6886 /* Look within any SIGN_EXTRACT or ZERO_EXTRACT
6887 to the MEM or REG within it. */
6888 while (GET_CODE (dest) == SIGN_EXTRACT
6889 || GET_CODE (dest) == ZERO_EXTRACT
6890 || GET_CODE (dest) == SUBREG
6891 || GET_CODE (dest) == STRICT_LOW_PART)
6893 sets[i].inner_dest_loc = &XEXP (dest, 0);
6894 dest = XEXP (dest, 0);
6897 sets[i].inner_dest = dest;
6899 if (GET_CODE (dest) == MEM)
6901 dest = fold_rtx (dest, insn);
6903 /* Decide whether we invalidate everything in memory,
6904 or just things at non-fixed places.
6905 Writing a large aggregate must invalidate everything
6906 because we don't know how long it is. */
6907 note_mem_written (dest, &writes_memory);
6910 /* Compute the hash code of the destination now,
6911 before the effects of this instruction are recorded,
6912 since the register values used in the address computation
6913 are those before this instruction. */
6914 sets[i].dest_hash = HASH (dest, mode);
6916 /* Don't enter a bit-field in the hash table
6917 because the value in it after the store
6918 may not equal what was stored, due to truncation. */
6920 if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT
6921 || GET_CODE (SET_DEST (sets[i].rtl)) == SIGN_EXTRACT)
6923 rtx width = XEXP (SET_DEST (sets[i].rtl), 1);
6925 if (src_const != 0 && GET_CODE (src_const) == CONST_INT
6926 && GET_CODE (width) == CONST_INT
6927 && INTVAL (width) < HOST_BITS_PER_WIDE_INT
6928 && ! (INTVAL (src_const)
6929 & ((HOST_WIDE_INT) (-1) << INTVAL (width))))
6930 /* Exception: if the value is constant,
6931 and it won't be truncated, record it. */
6935 /* This is chosen so that the destination will be invalidated
6936 but no new value will be recorded.
6937 We must invalidate because sometimes constant
6938 values can be recorded for bitfields. */
6939 sets[i].src_elt = 0;
6940 sets[i].src_volatile = 1;
6946 /* If only one set in a JUMP_INSN and it is now a no-op, we can delete
6948 else if (n_sets == 1 && dest == pc_rtx && src == pc_rtx)
6950 PUT_CODE (insn, NOTE);
6951 NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
6952 NOTE_SOURCE_FILE (insn) = 0;
6953 cse_jumps_altered = 1;
6954 /* One less use of the label this insn used to jump to. */
6955 --LABEL_NUSES (JUMP_LABEL (insn));
6956 /* No more processing for this set. */
6960 /* If this SET is now setting PC to a label, we know it used to
6961 be a conditional or computed branch. So we see if we can follow
6962 it. If it was a computed branch, delete it and re-emit. */
6963 else if (dest == pc_rtx && GET_CODE (src) == LABEL_REF)
6967 /* If this is not in the format for a simple branch and
6968 we are the only SET in it, re-emit it. */
6969 if (! simplejump_p (insn) && n_sets == 1)
6971 rtx new = emit_jump_insn_before (gen_jump (XEXP (src, 0)), insn);
6972 JUMP_LABEL (new) = XEXP (src, 0);
6973 LABEL_NUSES (XEXP (src, 0))++;
6978 /* Otherwise, force rerecognition, since it probably had
6979 a different pattern before.
6980 This shouldn't really be necessary, since whatever
6981 changed the source value above should have done this.
6982 Until the right place is found, might as well do this here. */
6983 INSN_CODE (insn) = -1;
6985 /* Now that we've converted this jump to an unconditional jump,
6986 there is dead code after it. Delete the dead code until we
6987 reach a BARRIER, the end of the function, or a label. Do
6988 not delete NOTEs except for NOTE_INSN_DELETED since later
6989 phases assume these notes are retained. */
6993 while (NEXT_INSN (p) != 0
6994 && GET_CODE (NEXT_INSN (p)) != BARRIER
6995 && GET_CODE (NEXT_INSN (p)) != CODE_LABEL)
6997 if (GET_CODE (NEXT_INSN (p)) != NOTE
6998 || NOTE_LINE_NUMBER (NEXT_INSN (p)) == NOTE_INSN_DELETED)
6999 delete_insn (NEXT_INSN (p));
7004 /* If we don't have a BARRIER immediately after INSN, put one there.
7005 Much code assumes that there are no NOTEs between a JUMP_INSN and
7008 if (NEXT_INSN (insn) == 0
7009 || GET_CODE (NEXT_INSN (insn)) != BARRIER)
7010 emit_barrier_before (NEXT_INSN (insn));
7012 /* We might have two BARRIERs separated by notes. Delete the second
7015 if (p != insn && NEXT_INSN (p) != 0
7016 && GET_CODE (NEXT_INSN (p)) == BARRIER)
7017 delete_insn (NEXT_INSN (p));
7019 cse_jumps_altered = 1;
7023 /* If destination is volatile, invalidate it and then do no further
7024 processing for this assignment. */
7026 else if (do_not_record)
7028 if (GET_CODE (dest) == REG || GET_CODE (dest) == SUBREG
7029 || GET_CODE (dest) == MEM)
7030 invalidate (dest, VOIDmode);
7031 else if (GET_CODE (dest) == STRICT_LOW_PART
7032 || GET_CODE (dest) == ZERO_EXTRACT)
7033 invalidate (XEXP (dest, 0), GET_MODE (dest));
7037 if (sets[i].rtl != 0 && dest != SET_DEST (sets[i].rtl))
7038 sets[i].dest_hash = HASH (SET_DEST (sets[i].rtl), mode);
7041 /* If setting CC0, record what it was set to, or a constant, if it
7042 is equivalent to a constant. If it is being set to a floating-point
7043 value, make a COMPARE with the appropriate constant of 0. If we
7044 don't do this, later code can interpret this as a test against
7045 const0_rtx, which can cause problems if we try to put it into an
7046 insn as a floating-point operand. */
7047 if (dest == cc0_rtx)
7049 this_insn_cc0 = src_const && mode != VOIDmode ? src_const : src;
7050 this_insn_cc0_mode = mode;
7051 if (FLOAT_MODE_P (mode))
7052 this_insn_cc0 = gen_rtx (COMPARE, VOIDmode, this_insn_cc0,
7058 /* Now enter all non-volatile source expressions in the hash table
7059 if they are not already present.
7060 Record their equivalence classes in src_elt.
7061 This way we can insert the corresponding destinations into
7062 the same classes even if the actual sources are no longer in them
7063 (having been invalidated). */
7065 if (src_eqv && src_eqv_elt == 0 && sets[0].rtl != 0 && ! src_eqv_volatile
7066 && ! rtx_equal_p (src_eqv, SET_DEST (sets[0].rtl)))
7068 register struct table_elt *elt;
7069 register struct table_elt *classp = sets[0].src_elt;
7070 rtx dest = SET_DEST (sets[0].rtl);
7071 enum machine_mode eqvmode = GET_MODE (dest);
7073 if (GET_CODE (dest) == STRICT_LOW_PART)
7075 eqvmode = GET_MODE (SUBREG_REG (XEXP (dest, 0)));
7078 if (insert_regs (src_eqv, classp, 0))
7080 rehash_using_reg (src_eqv);
7081 src_eqv_hash = HASH (src_eqv, eqvmode);
7083 elt = insert (src_eqv, classp, src_eqv_hash, eqvmode);
7084 elt->in_memory = src_eqv_in_memory;
7085 elt->in_struct = src_eqv_in_struct;
7088 /* Check to see if src_eqv_elt is the same as a set source which
7089 does not yet have an elt, and if so set the elt of the set source
7091 for (i = 0; i < n_sets; i++)
7092 if (sets[i].rtl && sets[i].src_elt == 0
7093 && rtx_equal_p (SET_SRC (sets[i].rtl), src_eqv))
7094 sets[i].src_elt = src_eqv_elt;
7097 for (i = 0; i < n_sets; i++)
7098 if (sets[i].rtl && ! sets[i].src_volatile
7099 && ! rtx_equal_p (SET_SRC (sets[i].rtl), SET_DEST (sets[i].rtl)))
7101 if (GET_CODE (SET_DEST (sets[i].rtl)) == STRICT_LOW_PART)
7103 /* REG_EQUAL in setting a STRICT_LOW_PART
7104 gives an equivalent for the entire destination register,
7105 not just for the subreg being stored in now.
7106 This is a more interesting equivalence, so we arrange later
7107 to treat the entire reg as the destination. */
7108 sets[i].src_elt = src_eqv_elt;
7109 sets[i].src_hash = src_eqv_hash;
7113 /* Insert source and constant equivalent into hash table, if not
7115 register struct table_elt *classp = src_eqv_elt;
7116 register rtx src = sets[i].src;
7117 register rtx dest = SET_DEST (sets[i].rtl);
7118 enum machine_mode mode
7119 = GET_MODE (src) == VOIDmode ? GET_MODE (dest) : GET_MODE (src);
7121 if (sets[i].src_elt == 0)
7123 register struct table_elt *elt;
7125 /* Note that these insert_regs calls cannot remove
7126 any of the src_elt's, because they would have failed to
7127 match if not still valid. */
7128 if (insert_regs (src, classp, 0))
7130 rehash_using_reg (src);
7131 sets[i].src_hash = HASH (src, mode);
7133 elt = insert (src, classp, sets[i].src_hash, mode);
7134 elt->in_memory = sets[i].src_in_memory;
7135 elt->in_struct = sets[i].src_in_struct;
7136 sets[i].src_elt = classp = elt;
7139 if (sets[i].src_const && sets[i].src_const_elt == 0
7140 && src != sets[i].src_const
7141 && ! rtx_equal_p (sets[i].src_const, src))
7142 sets[i].src_elt = insert (sets[i].src_const, classp,
7143 sets[i].src_const_hash, mode);
7146 else if (sets[i].src_elt == 0)
7147 /* If we did not insert the source into the hash table (e.g., it was
7148 volatile), note the equivalence class for the REG_EQUAL value, if any,
7149 so that the destination goes into that class. */
7150 sets[i].src_elt = src_eqv_elt;
7152 invalidate_from_clobbers (&writes_memory, x);
7154 /* Some registers are invalidated by subroutine calls. Memory is
7155 invalidated by non-constant calls. */
7157 if (GET_CODE (insn) == CALL_INSN)
7159 static struct write_data everything = {0, 1, 1, 1};
7161 if (! CONST_CALL_P (insn))
7162 invalidate_memory (&everything);
7163 invalidate_for_call ();
7166 /* Now invalidate everything set by this instruction.
7167 If a SUBREG or other funny destination is being set,
7168 sets[i].rtl is still nonzero, so here we invalidate the reg
7169 a part of which is being set. */
7171 for (i = 0; i < n_sets; i++)
7174 /* We can't use the inner dest, because the mode associated with
7175 a ZERO_EXTRACT is significant. */
7176 register rtx dest = SET_DEST (sets[i].rtl);
7178 /* Needed for registers to remove the register from its
7179 previous quantity's chain.
7180 Needed for memory if this is a nonvarying address, unless
7181 we have just done an invalidate_memory that covers even those. */
7182 if (GET_CODE (dest) == REG || GET_CODE (dest) == SUBREG
7183 || (GET_CODE (dest) == MEM && ! writes_memory.all
7184 && ! cse_rtx_addr_varies_p (dest)))
7185 invalidate (dest, VOIDmode);
7186 else if (GET_CODE (dest) == STRICT_LOW_PART
7187 || GET_CODE (dest) == ZERO_EXTRACT)
7188 invalidate (XEXP (dest, 0), GET_MODE (dest));
7191 /* Make sure registers mentioned in destinations
7192 are safe for use in an expression to be inserted.
7193 This removes from the hash table
7194 any invalid entry that refers to one of these registers.
7196 We don't care about the return value from mention_regs because
7197 we are going to hash the SET_DEST values unconditionally. */
7199 for (i = 0; i < n_sets; i++)
7200 if (sets[i].rtl && GET_CODE (SET_DEST (sets[i].rtl)) != REG)
7201 mention_regs (SET_DEST (sets[i].rtl));
7203 /* We may have just removed some of the src_elt's from the hash table.
7204 So replace each one with the current head of the same class. */
7206 for (i = 0; i < n_sets; i++)
7209 if (sets[i].src_elt && sets[i].src_elt->first_same_value == 0)
7210 /* If elt was removed, find current head of same class,
7211 or 0 if nothing remains of that class. */
7213 register struct table_elt *elt = sets[i].src_elt;
7215 while (elt && elt->prev_same_value)
7216 elt = elt->prev_same_value;
7218 while (elt && elt->first_same_value == 0)
7219 elt = elt->next_same_value;
7220 sets[i].src_elt = elt ? elt->first_same_value : 0;
7224 /* Now insert the destinations into their equivalence classes. */
7226 for (i = 0; i < n_sets; i++)
7229 register rtx dest = SET_DEST (sets[i].rtl);
7230 register struct table_elt *elt;
7232 /* Don't record value if we are not supposed to risk allocating
7233 floating-point values in registers that might be wider than
7235 if ((flag_float_store
7236 && GET_CODE (dest) == MEM
7237 && FLOAT_MODE_P (GET_MODE (dest)))
7238 /* Don't record values of destinations set inside a libcall block
7239 since we might delete the libcall. Things should have been set
7240 up so we won't want to reuse such a value, but we play it safe
7243 /* If we didn't put a REG_EQUAL value or a source into the hash
7244 table, there is no point is recording DEST. */
7245 || sets[i].src_elt == 0
7246 /* If DEST is a paradoxical SUBREG and SRC is a ZERO_EXTEND
7247 or SIGN_EXTEND, don't record DEST since it can cause
7248 some tracking to be wrong.
7250 ??? Think about this more later. */
7251 || (GET_CODE (dest) == SUBREG
7252 && (GET_MODE_SIZE (GET_MODE (dest))
7253 > GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))))
7254 && (GET_CODE (sets[i].src) == SIGN_EXTEND
7255 || GET_CODE (sets[i].src) == ZERO_EXTEND)))
7258 /* STRICT_LOW_PART isn't part of the value BEING set,
7259 and neither is the SUBREG inside it.
7260 Note that in this case SETS[I].SRC_ELT is really SRC_EQV_ELT. */
7261 if (GET_CODE (dest) == STRICT_LOW_PART)
7262 dest = SUBREG_REG (XEXP (dest, 0));
7264 if (GET_CODE (dest) == REG || GET_CODE (dest) == SUBREG)
7265 /* Registers must also be inserted into chains for quantities. */
7266 if (insert_regs (dest, sets[i].src_elt, 1))
7268 /* If `insert_regs' changes something, the hash code must be
7270 rehash_using_reg (dest);
7271 sets[i].dest_hash = HASH (dest, GET_MODE (dest));
7274 elt = insert (dest, sets[i].src_elt,
7275 sets[i].dest_hash, GET_MODE (dest));
7276 elt->in_memory = GET_CODE (sets[i].inner_dest) == MEM;
7279 /* This implicitly assumes a whole struct
7280 need not have MEM_IN_STRUCT_P.
7281 But a whole struct is *supposed* to have MEM_IN_STRUCT_P. */
7282 elt->in_struct = (MEM_IN_STRUCT_P (sets[i].inner_dest)
7283 || sets[i].inner_dest != SET_DEST (sets[i].rtl));
7286 /* If we have (set (subreg:m1 (reg:m2 foo) 0) (bar:m1)), M1 is no
7287 narrower than M2, and both M1 and M2 are the same number of words,
7288 we are also doing (set (reg:m2 foo) (subreg:m2 (bar:m1) 0)) so
7289 make that equivalence as well.
7291 However, BAR may have equivalences for which gen_lowpart_if_possible
7292 will produce a simpler value than gen_lowpart_if_possible applied to
7293 BAR (e.g., if BAR was ZERO_EXTENDed from M2), so we will scan all
7294 BAR's equivalences. If we don't get a simplified form, make
7295 the SUBREG. It will not be used in an equivalence, but will
7296 cause two similar assignments to be detected.
7298 Note the loop below will find SUBREG_REG (DEST) since we have
7299 already entered SRC and DEST of the SET in the table. */
7301 if (GET_CODE (dest) == SUBREG
7302 && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))) - 1)
7304 == (GET_MODE_SIZE (GET_MODE (dest)) - 1)/ UNITS_PER_WORD)
7305 && (GET_MODE_SIZE (GET_MODE (dest))
7306 >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))))
7307 && sets[i].src_elt != 0)
7309 enum machine_mode new_mode = GET_MODE (SUBREG_REG (dest));
7310 struct table_elt *elt, *classp = 0;
7312 for (elt = sets[i].src_elt->first_same_value; elt;
7313 elt = elt->next_same_value)
7317 struct table_elt *src_elt;
7319 /* Ignore invalid entries. */
7320 if (GET_CODE (elt->exp) != REG
7321 && ! exp_equiv_p (elt->exp, elt->exp, 1, 0))
7324 new_src = gen_lowpart_if_possible (new_mode, elt->exp);
7326 new_src = gen_rtx (SUBREG, new_mode, elt->exp, 0);
7328 src_hash = HASH (new_src, new_mode);
7329 src_elt = lookup (new_src, src_hash, new_mode);
7331 /* Put the new source in the hash table is if isn't
7335 if (insert_regs (new_src, classp, 0))
7337 rehash_using_reg (new_src);
7338 src_hash = HASH (new_src, new_mode);
7340 src_elt = insert (new_src, classp, src_hash, new_mode);
7341 src_elt->in_memory = elt->in_memory;
7342 src_elt->in_struct = elt->in_struct;
7344 else if (classp && classp != src_elt->first_same_value)
7345 /* Show that two things that we've seen before are
7346 actually the same. */
7347 merge_equiv_classes (src_elt, classp);
7349 classp = src_elt->first_same_value;
7354 /* Special handling for (set REG0 REG1)
7355 where REG0 is the "cheapest", cheaper than REG1.
7356 After cse, REG1 will probably not be used in the sequel,
7357 so (if easily done) change this insn to (set REG1 REG0) and
7358 replace REG1 with REG0 in the previous insn that computed their value.
7359 Then REG1 will become a dead store and won't cloud the situation
7360 for later optimizations.
7362 Do not make this change if REG1 is a hard register, because it will
7363 then be used in the sequel and we may be changing a two-operand insn
7364 into a three-operand insn.
7366 Also do not do this if we are operating on a copy of INSN. */
7368 if (n_sets == 1 && sets[0].rtl && GET_CODE (SET_DEST (sets[0].rtl)) == REG
7369 && NEXT_INSN (PREV_INSN (insn)) == insn
7370 && GET_CODE (SET_SRC (sets[0].rtl)) == REG
7371 && REGNO (SET_SRC (sets[0].rtl)) >= FIRST_PSEUDO_REGISTER
7372 && REGNO_QTY_VALID_P (REGNO (SET_SRC (sets[0].rtl)))
7373 && (qty_first_reg[reg_qty[REGNO (SET_SRC (sets[0].rtl))]]
7374 == REGNO (SET_DEST (sets[0].rtl))))
7376 rtx prev = PREV_INSN (insn);
7377 while (prev && GET_CODE (prev) == NOTE)
7378 prev = PREV_INSN (prev);
7380 if (prev && GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SET
7381 && SET_DEST (PATTERN (prev)) == SET_SRC (sets[0].rtl))
7383 rtx dest = SET_DEST (sets[0].rtl);
7384 rtx note = find_reg_note (prev, REG_EQUIV, NULL_RTX);
7386 validate_change (prev, & SET_DEST (PATTERN (prev)), dest, 1);
7387 validate_change (insn, & SET_DEST (sets[0].rtl),
7388 SET_SRC (sets[0].rtl), 1);
7389 validate_change (insn, & SET_SRC (sets[0].rtl), dest, 1);
7390 apply_change_group ();
7392 /* If REG1 was equivalent to a constant, REG0 is not. */
7394 PUT_REG_NOTE_KIND (note, REG_EQUAL);
7396 /* If there was a REG_WAS_0 note on PREV, remove it. Move
7397 any REG_WAS_0 note on INSN to PREV. */
7398 note = find_reg_note (prev, REG_WAS_0, NULL_RTX);
7400 remove_note (prev, note);
7402 note = find_reg_note (insn, REG_WAS_0, NULL_RTX);
7405 remove_note (insn, note);
7406 XEXP (note, 1) = REG_NOTES (prev);
7407 REG_NOTES (prev) = note;
7412 /* If this is a conditional jump insn, record any known equivalences due to
7413 the condition being tested. */
7415 last_jump_equiv_class = 0;
7416 if (GET_CODE (insn) == JUMP_INSN
7417 && n_sets == 1 && GET_CODE (x) == SET
7418 && GET_CODE (SET_SRC (x)) == IF_THEN_ELSE)
7419 record_jump_equiv (insn, 0);
7422 /* If the previous insn set CC0 and this insn no longer references CC0,
7423 delete the previous insn. Here we use the fact that nothing expects CC0
7424 to be valid over an insn, which is true until the final pass. */
7425 if (prev_insn && GET_CODE (prev_insn) == INSN
7426 && (tem = single_set (prev_insn)) != 0
7427 && SET_DEST (tem) == cc0_rtx
7428 && ! reg_mentioned_p (cc0_rtx, x))
7430 PUT_CODE (prev_insn, NOTE);
7431 NOTE_LINE_NUMBER (prev_insn) = NOTE_INSN_DELETED;
7432 NOTE_SOURCE_FILE (prev_insn) = 0;
7435 prev_insn_cc0 = this_insn_cc0;
7436 prev_insn_cc0_mode = this_insn_cc0_mode;
7442 /* Store 1 in *WRITES_PTR for those categories of memory ref
7443 that must be invalidated when the expression WRITTEN is stored in.
7444 If WRITTEN is null, say everything must be invalidated. */
7447 note_mem_written (written, writes_ptr)
7449 struct write_data *writes_ptr;
7451 static struct write_data everything = {0, 1, 1, 1};
7454 *writes_ptr = everything;
7455 else if (GET_CODE (written) == MEM)
7457 /* Pushing or popping the stack invalidates just the stack pointer. */
7458 rtx addr = XEXP (written, 0);
7459 if ((GET_CODE (addr) == PRE_DEC || GET_CODE (addr) == PRE_INC
7460 || GET_CODE (addr) == POST_DEC || GET_CODE (addr) == POST_INC)
7461 && GET_CODE (XEXP (addr, 0)) == REG
7462 && REGNO (XEXP (addr, 0)) == STACK_POINTER_REGNUM)
7467 else if (GET_MODE (written) == BLKmode)
7468 *writes_ptr = everything;
7469 /* (mem (scratch)) means clobber everything. */
7470 else if (GET_CODE (addr) == SCRATCH)
7471 *writes_ptr = everything;
7472 else if (cse_rtx_addr_varies_p (written))
7474 /* A varying address that is a sum indicates an array element,
7475 and that's just as good as a structure element
7476 in implying that we need not invalidate scalar variables.
7477 However, we must allow QImode aliasing of scalars, because the
7478 ANSI C standard allows character pointers to alias anything. */
7479 if (! ((MEM_IN_STRUCT_P (written)
7480 || GET_CODE (XEXP (written, 0)) == PLUS)
7481 && GET_MODE (written) != QImode))
7482 writes_ptr->all = 1;
7483 writes_ptr->nonscalar = 1;
7485 writes_ptr->var = 1;
7489 /* Perform invalidation on the basis of everything about an insn
7490 except for invalidating the actual places that are SET in it.
7491 This includes the places CLOBBERed, and anything that might
7492 alias with something that is SET or CLOBBERed.
7494 W points to the writes_memory for this insn, a struct write_data
7495 saying which kinds of memory references must be invalidated.
7496 X is the pattern of the insn. */
7499 invalidate_from_clobbers (w, x)
7500 struct write_data *w;
7503 /* If W->var is not set, W specifies no action.
7504 If W->all is set, this step gets all memory refs
7505 so they can be ignored in the rest of this function. */
7507 invalidate_memory (w);
7511 if (reg_tick[STACK_POINTER_REGNUM] >= 0)
7512 reg_tick[STACK_POINTER_REGNUM]++;
7514 /* This should be *very* rare. */
7515 if (TEST_HARD_REG_BIT (hard_regs_in_table, STACK_POINTER_REGNUM))
7516 invalidate (stack_pointer_rtx, VOIDmode);
7519 if (GET_CODE (x) == CLOBBER)
7521 rtx ref = XEXP (x, 0);
7524 if (GET_CODE (ref) == REG || GET_CODE (ref) == SUBREG
7525 || (GET_CODE (ref) == MEM && ! w->all))
7526 invalidate (ref, VOIDmode);
7527 else if (GET_CODE (ref) == STRICT_LOW_PART
7528 || GET_CODE (ref) == ZERO_EXTRACT)
7529 invalidate (XEXP (ref, 0), GET_MODE (ref));
7532 else if (GET_CODE (x) == PARALLEL)
7535 for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
7537 register rtx y = XVECEXP (x, 0, i);
7538 if (GET_CODE (y) == CLOBBER)
7540 rtx ref = XEXP (y, 0);
7543 if (GET_CODE (ref) == REG || GET_CODE (ref) == SUBREG
7544 || (GET_CODE (ref) == MEM && !w->all))
7545 invalidate (ref, VOIDmode);
7546 else if (GET_CODE (ref) == STRICT_LOW_PART
7547 || GET_CODE (ref) == ZERO_EXTRACT)
7548 invalidate (XEXP (ref, 0), GET_MODE (ref));
7555 /* Process X, part of the REG_NOTES of an insn. Look at any REG_EQUAL notes
7556 and replace any registers in them with either an equivalent constant
7557 or the canonical form of the register. If we are inside an address,
7558 only do this if the address remains valid.
7560 OBJECT is 0 except when within a MEM in which case it is the MEM.
7562 Return the replacement for X. */
7565 cse_process_notes (x, object)
7569 enum rtx_code code = GET_CODE (x);
7570 char *fmt = GET_RTX_FORMAT (code);
7586 XEXP (x, 0) = cse_process_notes (XEXP (x, 0), x);
7591 if (REG_NOTE_KIND (x) == REG_EQUAL)
7592 XEXP (x, 0) = cse_process_notes (XEXP (x, 0), NULL_RTX);
7594 XEXP (x, 1) = cse_process_notes (XEXP (x, 1), NULL_RTX);
7600 rtx new = cse_process_notes (XEXP (x, 0), object);
7601 /* We don't substitute VOIDmode constants into these rtx,
7602 since they would impede folding. */
7603 if (GET_MODE (new) != VOIDmode)
7604 validate_change (object, &XEXP (x, 0), new, 0);
7609 i = reg_qty[REGNO (x)];
7611 /* Return a constant or a constant register. */
7612 if (REGNO_QTY_VALID_P (REGNO (x))
7613 && qty_const[i] != 0
7614 && (CONSTANT_P (qty_const[i])
7615 || GET_CODE (qty_const[i]) == REG))
7617 rtx new = gen_lowpart_if_possible (GET_MODE (x), qty_const[i]);
7622 /* Otherwise, canonicalize this register. */
7623 return canon_reg (x, NULL_RTX);
7626 for (i = 0; i < GET_RTX_LENGTH (code); i++)
7628 validate_change (object, &XEXP (x, i),
7629 cse_process_notes (XEXP (x, i), object), 0);
7634 /* Find common subexpressions between the end test of a loop and the beginning
7635 of the loop. LOOP_START is the CODE_LABEL at the start of a loop.
7637 Often we have a loop where an expression in the exit test is used
7638 in the body of the loop. For example "while (*p) *q++ = *p++;".
7639 Because of the way we duplicate the loop exit test in front of the loop,
7640 however, we don't detect that common subexpression. This will be caught
7641 when global cse is implemented, but this is a quite common case.
7643 This function handles the most common cases of these common expressions.
7644 It is called after we have processed the basic block ending with the
7645 NOTE_INSN_LOOP_END note that ends a loop and the previous JUMP_INSN
7646 jumps to a label used only once. */
7649 cse_around_loop (loop_start)
7654 struct table_elt *p;
7656 /* If the jump at the end of the loop doesn't go to the start, we don't
7658 for (insn = PREV_INSN (loop_start);
7659 insn && (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0);
7660 insn = PREV_INSN (insn))
7664 || GET_CODE (insn) != NOTE
7665 || NOTE_LINE_NUMBER (insn) != NOTE_INSN_LOOP_BEG)
7668 /* If the last insn of the loop (the end test) was an NE comparison,
7669 we will interpret it as an EQ comparison, since we fell through
7670 the loop. Any equivalences resulting from that comparison are
7671 therefore not valid and must be invalidated. */
7672 if (last_jump_equiv_class)
7673 for (p = last_jump_equiv_class->first_same_value; p;
7674 p = p->next_same_value)
7675 if (GET_CODE (p->exp) == MEM || GET_CODE (p->exp) == REG
7676 || (GET_CODE (p->exp) == SUBREG
7677 && GET_CODE (SUBREG_REG (p->exp)) == REG))
7678 invalidate (p->exp, VOIDmode);
7679 else if (GET_CODE (p->exp) == STRICT_LOW_PART
7680 || GET_CODE (p->exp) == ZERO_EXTRACT)
7681 invalidate (XEXP (p->exp, 0), GET_MODE (p->exp));
7683 /* Process insns starting after LOOP_START until we hit a CALL_INSN or
7684 a CODE_LABEL (we could handle a CALL_INSN, but it isn't worth it).
7686 The only thing we do with SET_DEST is invalidate entries, so we
7687 can safely process each SET in order. It is slightly less efficient
7688 to do so, but we only want to handle the most common cases. */
7690 for (insn = NEXT_INSN (loop_start);
7691 GET_CODE (insn) != CALL_INSN && GET_CODE (insn) != CODE_LABEL
7692 && ! (GET_CODE (insn) == NOTE
7693 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
7694 insn = NEXT_INSN (insn))
7696 if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
7697 && (GET_CODE (PATTERN (insn)) == SET
7698 || GET_CODE (PATTERN (insn)) == CLOBBER))
7699 cse_set_around_loop (PATTERN (insn), insn, loop_start);
7700 else if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
7701 && GET_CODE (PATTERN (insn)) == PARALLEL)
7702 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
7703 if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET
7704 || GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == CLOBBER)
7705 cse_set_around_loop (XVECEXP (PATTERN (insn), 0, i), insn,
7710 /* Variable used for communications between the next two routines. */
7712 static struct write_data skipped_writes_memory;
7714 /* Process one SET of an insn that was skipped. We ignore CLOBBERs
7715 since they are done elsewhere. This function is called via note_stores. */
7718 invalidate_skipped_set (dest, set)
7722 if (GET_CODE (set) == CLOBBER
7729 if (GET_CODE (dest) == MEM)
7730 note_mem_written (dest, &skipped_writes_memory);
7732 /* There are times when an address can appear varying and be a PLUS
7733 during this scan when it would be a fixed address were we to know
7734 the proper equivalences. So promote "nonscalar" to be "all". */
7735 if (skipped_writes_memory.nonscalar)
7736 skipped_writes_memory.all = 1;
7738 if (GET_CODE (dest) == REG || GET_CODE (dest) == SUBREG
7739 || (! skipped_writes_memory.all && ! cse_rtx_addr_varies_p (dest)))
7740 invalidate (dest, VOIDmode);
7741 else if (GET_CODE (dest) == STRICT_LOW_PART
7742 || GET_CODE (dest) == ZERO_EXTRACT)
7743 invalidate (XEXP (dest, 0), GET_MODE (dest));
7746 /* Invalidate all insns from START up to the end of the function or the
7747 next label. This called when we wish to CSE around a block that is
7748 conditionally executed. */
7751 invalidate_skipped_block (start)
7755 static struct write_data init = {0, 0, 0, 0};
7756 static struct write_data everything = {0, 1, 1, 1};
7758 for (insn = start; insn && GET_CODE (insn) != CODE_LABEL;
7759 insn = NEXT_INSN (insn))
7761 if (GET_RTX_CLASS (GET_CODE (insn)) != 'i')
7764 skipped_writes_memory = init;
7766 if (GET_CODE (insn) == CALL_INSN)
7768 invalidate_for_call ();
7769 skipped_writes_memory = everything;
7772 note_stores (PATTERN (insn), invalidate_skipped_set);
7773 invalidate_from_clobbers (&skipped_writes_memory, PATTERN (insn));
7777 /* Used for communication between the following two routines; contains a
7778 value to be checked for modification. */
7780 static rtx cse_check_loop_start_value;
7782 /* If modifying X will modify the value in CSE_CHECK_LOOP_START_VALUE,
7783 indicate that fact by setting CSE_CHECK_LOOP_START_VALUE to 0. */
7786 cse_check_loop_start (x, set)
7790 if (cse_check_loop_start_value == 0
7791 || GET_CODE (x) == CC0 || GET_CODE (x) == PC)
7794 if ((GET_CODE (x) == MEM && GET_CODE (cse_check_loop_start_value) == MEM)
7795 || reg_overlap_mentioned_p (x, cse_check_loop_start_value))
7796 cse_check_loop_start_value = 0;
7799 /* X is a SET or CLOBBER contained in INSN that was found near the start of
7800 a loop that starts with the label at LOOP_START.
7802 If X is a SET, we see if its SET_SRC is currently in our hash table.
7803 If so, we see if it has a value equal to some register used only in the
7804 loop exit code (as marked by jump.c).
7806 If those two conditions are true, we search backwards from the start of
7807 the loop to see if that same value was loaded into a register that still
7808 retains its value at the start of the loop.
7810 If so, we insert an insn after the load to copy the destination of that
7811 load into the equivalent register and (try to) replace our SET_SRC with that
7814 In any event, we invalidate whatever this SET or CLOBBER modifies. */
7817 cse_set_around_loop (x, insn, loop_start)
7822 struct table_elt *src_elt;
7823 static struct write_data init = {0, 0, 0, 0};
7824 struct write_data writes_memory;
7826 writes_memory = init;
7828 /* If this is a SET, see if we can replace SET_SRC, but ignore SETs that
7829 are setting PC or CC0 or whose SET_SRC is already a register. */
7830 if (GET_CODE (x) == SET
7831 && GET_CODE (SET_DEST (x)) != PC && GET_CODE (SET_DEST (x)) != CC0
7832 && GET_CODE (SET_SRC (x)) != REG)
7834 src_elt = lookup (SET_SRC (x),
7835 HASH (SET_SRC (x), GET_MODE (SET_DEST (x))),
7836 GET_MODE (SET_DEST (x)));
7839 for (src_elt = src_elt->first_same_value; src_elt;
7840 src_elt = src_elt->next_same_value)
7841 if (GET_CODE (src_elt->exp) == REG && REG_LOOP_TEST_P (src_elt->exp)
7842 && COST (src_elt->exp) < COST (SET_SRC (x)))
7846 /* Look for an insn in front of LOOP_START that sets
7847 something in the desired mode to SET_SRC (x) before we hit
7848 a label or CALL_INSN. */
7850 for (p = prev_nonnote_insn (loop_start);
7851 p && GET_CODE (p) != CALL_INSN
7852 && GET_CODE (p) != CODE_LABEL;
7853 p = prev_nonnote_insn (p))
7854 if ((set = single_set (p)) != 0
7855 && GET_CODE (SET_DEST (set)) == REG
7856 && GET_MODE (SET_DEST (set)) == src_elt->mode
7857 && rtx_equal_p (SET_SRC (set), SET_SRC (x)))
7859 /* We now have to ensure that nothing between P
7860 and LOOP_START modified anything referenced in
7861 SET_SRC (x). We know that nothing within the loop
7862 can modify it, or we would have invalidated it in
7866 cse_check_loop_start_value = SET_SRC (x);
7867 for (q = p; q != loop_start; q = NEXT_INSN (q))
7868 if (GET_RTX_CLASS (GET_CODE (q)) == 'i')
7869 note_stores (PATTERN (q), cse_check_loop_start);
7871 /* If nothing was changed and we can replace our
7872 SET_SRC, add an insn after P to copy its destination
7873 to what we will be replacing SET_SRC with. */
7874 if (cse_check_loop_start_value
7875 && validate_change (insn, &SET_SRC (x),
7877 emit_insn_after (gen_move_insn (src_elt->exp,
7885 /* Now invalidate anything modified by X. */
7886 note_mem_written (SET_DEST (x), &writes_memory);
7888 if (writes_memory.var)
7889 invalidate_memory (&writes_memory);
7891 /* See comment on similar code in cse_insn for explanation of these tests. */
7892 if (GET_CODE (SET_DEST (x)) == REG || GET_CODE (SET_DEST (x)) == SUBREG
7893 || (GET_CODE (SET_DEST (x)) == MEM && ! writes_memory.all
7894 && ! cse_rtx_addr_varies_p (SET_DEST (x))))
7895 invalidate (SET_DEST (x), VOIDmode);
7896 else if (GET_CODE (SET_DEST (x)) == STRICT_LOW_PART
7897 || GET_CODE (SET_DEST (x)) == ZERO_EXTRACT)
7898 invalidate (XEXP (SET_DEST (x), 0), GET_MODE (SET_DEST (x)));
7901 /* Find the end of INSN's basic block and return its range,
7902 the total number of SETs in all the insns of the block, the last insn of the
7903 block, and the branch path.
7905 The branch path indicates which branches should be followed. If a non-zero
7906 path size is specified, the block should be rescanned and a different set
7907 of branches will be taken. The branch path is only used if
7908 FLAG_CSE_FOLLOW_JUMPS or FLAG_CSE_SKIP_BLOCKS is non-zero.
7910 DATA is a pointer to a struct cse_basic_block_data, defined below, that is
7911 used to describe the block. It is filled in with the information about
7912 the current block. The incoming structure's branch path, if any, is used
7913 to construct the output branch path. */
7916 cse_end_of_basic_block (insn, data, follow_jumps, after_loop, skip_blocks)
7918 struct cse_basic_block_data *data;
7925 int low_cuid = INSN_CUID (insn), high_cuid = INSN_CUID (insn);
7926 rtx next = GET_RTX_CLASS (GET_CODE (insn)) == 'i' ? insn : next_real_insn (insn);
7927 int path_size = data->path_size;
7931 /* Update the previous branch path, if any. If the last branch was
7932 previously TAKEN, mark it NOT_TAKEN. If it was previously NOT_TAKEN,
7933 shorten the path by one and look at the previous branch. We know that
7934 at least one branch must have been taken if PATH_SIZE is non-zero. */
7935 while (path_size > 0)
7937 if (data->path[path_size - 1].status != NOT_TAKEN)
7939 data->path[path_size - 1].status = NOT_TAKEN;
7946 /* Scan to end of this basic block. */
7947 while (p && GET_CODE (p) != CODE_LABEL)
7949 /* Don't cse out the end of a loop. This makes a difference
7950 only for the unusual loops that always execute at least once;
7951 all other loops have labels there so we will stop in any case.
7952 Cse'ing out the end of the loop is dangerous because it
7953 might cause an invariant expression inside the loop
7954 to be reused after the end of the loop. This would make it
7955 hard to move the expression out of the loop in loop.c,
7956 especially if it is one of several equivalent expressions
7957 and loop.c would like to eliminate it.
7959 If we are running after loop.c has finished, we can ignore
7960 the NOTE_INSN_LOOP_END. */
7962 if (! after_loop && GET_CODE (p) == NOTE
7963 && NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)
7966 /* Don't cse over a call to setjmp; on some machines (eg vax)
7967 the regs restored by the longjmp come from
7968 a later time than the setjmp. */
7969 if (GET_CODE (p) == NOTE
7970 && NOTE_LINE_NUMBER (p) == NOTE_INSN_SETJMP)
7973 /* A PARALLEL can have lots of SETs in it,
7974 especially if it is really an ASM_OPERANDS. */
7975 if (GET_RTX_CLASS (GET_CODE (p)) == 'i'
7976 && GET_CODE (PATTERN (p)) == PARALLEL)
7977 nsets += XVECLEN (PATTERN (p), 0);
7978 else if (GET_CODE (p) != NOTE)
7981 /* Ignore insns made by CSE; they cannot affect the boundaries of
7984 if (INSN_UID (p) <= max_uid && INSN_CUID (p) > high_cuid)
7985 high_cuid = INSN_CUID (p);
7986 if (INSN_UID (p) <= max_uid && INSN_CUID (p) < low_cuid)
7987 low_cuid = INSN_CUID (p);
7989 /* See if this insn is in our branch path. If it is and we are to
7991 if (path_entry < path_size && data->path[path_entry].branch == p)
7993 if (data->path[path_entry].status != NOT_TAKEN)
7996 /* Point to next entry in path, if any. */
8000 /* If this is a conditional jump, we can follow it if -fcse-follow-jumps
8001 was specified, we haven't reached our maximum path length, there are
8002 insns following the target of the jump, this is the only use of the
8003 jump label, and the target label is preceded by a BARRIER.
8005 Alternatively, we can follow the jump if it branches around a
8006 block of code and there are no other branches into the block.
8007 In this case invalidate_skipped_block will be called to invalidate any
8008 registers set in the block when following the jump. */
8010 else if ((follow_jumps || skip_blocks) && path_size < PATHLENGTH - 1
8011 && GET_CODE (p) == JUMP_INSN
8012 && GET_CODE (PATTERN (p)) == SET
8013 && GET_CODE (SET_SRC (PATTERN (p))) == IF_THEN_ELSE
8014 && LABEL_NUSES (JUMP_LABEL (p)) == 1
8015 && NEXT_INSN (JUMP_LABEL (p)) != 0)
8017 for (q = PREV_INSN (JUMP_LABEL (p)); q; q = PREV_INSN (q))
8018 if ((GET_CODE (q) != NOTE
8019 || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END
8020 || NOTE_LINE_NUMBER (q) == NOTE_INSN_SETJMP)
8021 && (GET_CODE (q) != CODE_LABEL || LABEL_NUSES (q) != 0))
8024 /* If we ran into a BARRIER, this code is an extension of the
8025 basic block when the branch is taken. */
8026 if (follow_jumps && q != 0 && GET_CODE (q) == BARRIER)
8028 /* Don't allow ourself to keep walking around an
8029 always-executed loop. */
8030 if (next_real_insn (q) == next)
8036 /* Similarly, don't put a branch in our path more than once. */
8037 for (i = 0; i < path_entry; i++)
8038 if (data->path[i].branch == p)
8041 if (i != path_entry)
8044 data->path[path_entry].branch = p;
8045 data->path[path_entry++].status = TAKEN;
8047 /* This branch now ends our path. It was possible that we
8048 didn't see this branch the last time around (when the
8049 insn in front of the target was a JUMP_INSN that was
8050 turned into a no-op). */
8051 path_size = path_entry;
8054 /* Mark block so we won't scan it again later. */
8055 PUT_MODE (NEXT_INSN (p), QImode);
8057 /* Detect a branch around a block of code. */
8058 else if (skip_blocks && q != 0 && GET_CODE (q) != CODE_LABEL)
8062 if (next_real_insn (q) == next)
8068 for (i = 0; i < path_entry; i++)
8069 if (data->path[i].branch == p)
8072 if (i != path_entry)
8075 /* This is no_labels_between_p (p, q) with an added check for
8076 reaching the end of a function (in case Q precedes P). */
8077 for (tmp = NEXT_INSN (p); tmp && tmp != q; tmp = NEXT_INSN (tmp))
8078 if (GET_CODE (tmp) == CODE_LABEL)
8083 data->path[path_entry].branch = p;
8084 data->path[path_entry++].status = AROUND;
8086 path_size = path_entry;
8089 /* Mark block so we won't scan it again later. */
8090 PUT_MODE (NEXT_INSN (p), QImode);
8097 data->low_cuid = low_cuid;
8098 data->high_cuid = high_cuid;
8099 data->nsets = nsets;
8102 /* If all jumps in the path are not taken, set our path length to zero
8103 so a rescan won't be done. */
8104 for (i = path_size - 1; i >= 0; i--)
8105 if (data->path[i].status != NOT_TAKEN)
8109 data->path_size = 0;
8111 data->path_size = path_size;
8113 /* End the current branch path. */
8114 data->path[path_size].branch = 0;
8117 /* Perform cse on the instructions of a function.
8118 F is the first instruction.
8119 NREGS is one plus the highest pseudo-reg number used in the instruction.
8121 AFTER_LOOP is 1 if this is the cse call done after loop optimization
8122 (only if -frerun-cse-after-loop).
8124 Returns 1 if jump_optimize should be redone due to simplifications
8125 in conditional jump instructions. */
8128 cse_main (f, nregs, after_loop, file)
8134 struct cse_basic_block_data val;
8135 register rtx insn = f;
8138 cse_jumps_altered = 0;
8139 constant_pool_entries_cost = 0;
8146 all_minus_one = (int *) alloca (nregs * sizeof (int));
8147 consec_ints = (int *) alloca (nregs * sizeof (int));
8149 for (i = 0; i < nregs; i++)
8151 all_minus_one[i] = -1;
8155 reg_next_eqv = (int *) alloca (nregs * sizeof (int));
8156 reg_prev_eqv = (int *) alloca (nregs * sizeof (int));
8157 reg_qty = (int *) alloca (nregs * sizeof (int));
8158 reg_in_table = (int *) alloca (nregs * sizeof (int));
8159 reg_tick = (int *) alloca (nregs * sizeof (int));
8161 #ifdef LOAD_EXTEND_OP
8163 /* Allocate scratch rtl here. cse_insn will fill in the memory reference
8164 and change the code and mode as appropriate. */
8165 memory_extend_rtx = gen_rtx (ZERO_EXTEND, VOIDmode, 0);
8168 /* Discard all the free elements of the previous function
8169 since they are allocated in the temporarily obstack. */
8170 bzero ((char *) table, sizeof table);
8171 free_element_chain = 0;
8172 n_elements_made = 0;
8174 /* Find the largest uid. */
8176 max_uid = get_max_uid ();
8177 uid_cuid = (int *) alloca ((max_uid + 1) * sizeof (int));
8178 bzero ((char *) uid_cuid, (max_uid + 1) * sizeof (int));
8180 /* Compute the mapping from uids to cuids.
8181 CUIDs are numbers assigned to insns, like uids,
8182 except that cuids increase monotonically through the code.
8183 Don't assign cuids to line-number NOTEs, so that the distance in cuids
8184 between two insns is not affected by -g. */
8186 for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
8188 if (GET_CODE (insn) != NOTE
8189 || NOTE_LINE_NUMBER (insn) < 0)
8190 INSN_CUID (insn) = ++i;
8192 /* Give a line number note the same cuid as preceding insn. */
8193 INSN_CUID (insn) = i;
8196 /* Initialize which registers are clobbered by calls. */
8198 CLEAR_HARD_REG_SET (regs_invalidated_by_call);
8200 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
8201 if ((call_used_regs[i]
8202 /* Used to check !fixed_regs[i] here, but that isn't safe;
8203 fixed regs are still call-clobbered, and sched can get
8204 confused if they can "live across calls".
8206 The frame pointer is always preserved across calls. The arg
8207 pointer is if it is fixed. The stack pointer usually is, unless
8208 RETURN_POPS_ARGS, in which case an explicit CLOBBER
8209 will be present. If we are generating PIC code, the PIC offset
8210 table register is preserved across calls. */
8212 && i != STACK_POINTER_REGNUM
8213 && i != FRAME_POINTER_REGNUM
8214 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
8215 && i != HARD_FRAME_POINTER_REGNUM
8217 #if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM
8218 && ! (i == ARG_POINTER_REGNUM && fixed_regs[i])
8220 #if defined (PIC_OFFSET_TABLE_REGNUM) && !defined (PIC_OFFSET_TABLE_REG_CALL_CLOBBERED)
8221 && ! (i == PIC_OFFSET_TABLE_REGNUM && flag_pic)
8225 SET_HARD_REG_BIT (regs_invalidated_by_call, i);
8227 /* Loop over basic blocks.
8228 Compute the maximum number of qty's needed for each basic block
8229 (which is 2 for each SET). */
8233 cse_end_of_basic_block (insn, &val, flag_cse_follow_jumps, after_loop,
8234 flag_cse_skip_blocks);
8236 /* If this basic block was already processed or has no sets, skip it. */
8237 if (val.nsets == 0 || GET_MODE (insn) == QImode)
8239 PUT_MODE (insn, VOIDmode);
8240 insn = (val.last ? NEXT_INSN (val.last) : 0);
8245 cse_basic_block_start = val.low_cuid;
8246 cse_basic_block_end = val.high_cuid;
8247 max_qty = val.nsets * 2;
8250 fprintf (file, ";; Processing block from %d to %d, %d sets.\n",
8251 INSN_UID (insn), val.last ? INSN_UID (val.last) : 0,
8254 /* Make MAX_QTY bigger to give us room to optimize
8255 past the end of this basic block, if that should prove useful. */
8261 /* If this basic block is being extended by following certain jumps,
8262 (see `cse_end_of_basic_block'), we reprocess the code from the start.
8263 Otherwise, we start after this basic block. */
8264 if (val.path_size > 0)
8265 cse_basic_block (insn, val.last, val.path, 0);
8268 int old_cse_jumps_altered = cse_jumps_altered;
8271 /* When cse changes a conditional jump to an unconditional
8272 jump, we want to reprocess the block, since it will give
8273 us a new branch path to investigate. */
8274 cse_jumps_altered = 0;
8275 temp = cse_basic_block (insn, val.last, val.path, ! after_loop);
8276 if (cse_jumps_altered == 0
8277 || (flag_cse_follow_jumps == 0 && flag_cse_skip_blocks == 0))
8280 cse_jumps_altered |= old_cse_jumps_altered;
8288 /* Tell refers_to_mem_p that qty_const info is not available. */
8291 if (max_elements_made < n_elements_made)
8292 max_elements_made = n_elements_made;
8294 return cse_jumps_altered;
8297 /* Process a single basic block. FROM and TO and the limits of the basic
8298 block. NEXT_BRANCH points to the branch path when following jumps or
8299 a null path when not following jumps.
8301 AROUND_LOOP is non-zero if we are to try to cse around to the start of a
8302 loop. This is true when we are being called for the last time on a
8303 block and this CSE pass is before loop.c. */
8306 cse_basic_block (from, to, next_branch, around_loop)
8307 register rtx from, to;
8308 struct branch_path *next_branch;
8313 int in_libcall_block = 0;
8315 /* Each of these arrays is undefined before max_reg, so only allocate
8316 the space actually needed and adjust the start below. */
8318 qty_first_reg = (int *) alloca ((max_qty - max_reg) * sizeof (int));
8319 qty_last_reg = (int *) alloca ((max_qty - max_reg) * sizeof (int));
8320 qty_mode= (enum machine_mode *) alloca ((max_qty - max_reg) * sizeof (enum machine_mode));
8321 qty_const = (rtx *) alloca ((max_qty - max_reg) * sizeof (rtx));
8322 qty_const_insn = (rtx *) alloca ((max_qty - max_reg) * sizeof (rtx));
8324 = (enum rtx_code *) alloca ((max_qty - max_reg) * sizeof (enum rtx_code));
8325 qty_comparison_qty = (int *) alloca ((max_qty - max_reg) * sizeof (int));
8326 qty_comparison_const = (rtx *) alloca ((max_qty - max_reg) * sizeof (rtx));
8328 qty_first_reg -= max_reg;
8329 qty_last_reg -= max_reg;
8330 qty_mode -= max_reg;
8331 qty_const -= max_reg;
8332 qty_const_insn -= max_reg;
8333 qty_comparison_code -= max_reg;
8334 qty_comparison_qty -= max_reg;
8335 qty_comparison_const -= max_reg;
8339 /* TO might be a label. If so, protect it from being deleted. */
8340 if (to != 0 && GET_CODE (to) == CODE_LABEL)
8343 for (insn = from; insn != to; insn = NEXT_INSN (insn))
8345 register enum rtx_code code;
8347 /* See if this is a branch that is part of the path. If so, and it is
8348 to be taken, do so. */
8349 if (next_branch->branch == insn)
8351 enum taken status = next_branch++->status;
8352 if (status != NOT_TAKEN)
8354 if (status == TAKEN)
8355 record_jump_equiv (insn, 1);
8357 invalidate_skipped_block (NEXT_INSN (insn));
8359 /* Set the last insn as the jump insn; it doesn't affect cc0.
8360 Then follow this branch. */
8365 insn = JUMP_LABEL (insn);
8370 code = GET_CODE (insn);
8371 if (GET_MODE (insn) == QImode)
8372 PUT_MODE (insn, VOIDmode);
8374 if (GET_RTX_CLASS (code) == 'i')
8376 /* Process notes first so we have all notes in canonical forms when
8377 looking for duplicate operations. */
8379 if (REG_NOTES (insn))
8380 REG_NOTES (insn) = cse_process_notes (REG_NOTES (insn), NULL_RTX);
8382 /* Track when we are inside in LIBCALL block. Inside such a block,
8383 we do not want to record destinations. The last insn of a
8384 LIBCALL block is not considered to be part of the block, since
8385 its destination is the result of the block and hence should be
8388 if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))
8389 in_libcall_block = 1;
8390 else if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
8391 in_libcall_block = 0;
8393 cse_insn (insn, in_libcall_block);
8396 /* If INSN is now an unconditional jump, skip to the end of our
8397 basic block by pretending that we just did the last insn in the
8398 basic block. If we are jumping to the end of our block, show
8399 that we can have one usage of TO. */
8401 if (simplejump_p (insn))
8406 if (JUMP_LABEL (insn) == to)
8409 /* Maybe TO was deleted because the jump is unconditional.
8410 If so, there is nothing left in this basic block. */
8411 /* ??? Perhaps it would be smarter to set TO
8412 to whatever follows this insn,
8413 and pretend the basic block had always ended here. */
8414 if (INSN_DELETED_P (to))
8417 insn = PREV_INSN (to);
8420 /* See if it is ok to keep on going past the label
8421 which used to end our basic block. Remember that we incremented
8422 the count of that label, so we decrement it here. If we made
8423 a jump unconditional, TO_USAGE will be one; in that case, we don't
8424 want to count the use in that jump. */
8426 if (to != 0 && NEXT_INSN (insn) == to
8427 && GET_CODE (to) == CODE_LABEL && --LABEL_NUSES (to) == to_usage)
8429 struct cse_basic_block_data val;
8431 insn = NEXT_INSN (to);
8433 if (LABEL_NUSES (to) == 0)
8436 /* Find the end of the following block. Note that we won't be
8437 following branches in this case. If TO was the last insn
8438 in the function, we are done. Similarly, if we deleted the
8439 insn after TO, it must have been because it was preceded by
8440 a BARRIER. In that case, we are done with this block because it
8441 has no continuation. */
8443 if (insn == 0 || INSN_DELETED_P (insn))
8448 cse_end_of_basic_block (insn, &val, 0, 0, 0);
8450 /* If the tables we allocated have enough space left
8451 to handle all the SETs in the next basic block,
8452 continue through it. Otherwise, return,
8453 and that block will be scanned individually. */
8454 if (val.nsets * 2 + next_qty > max_qty)
8457 cse_basic_block_start = val.low_cuid;
8458 cse_basic_block_end = val.high_cuid;
8461 /* Prevent TO from being deleted if it is a label. */
8462 if (to != 0 && GET_CODE (to) == CODE_LABEL)
8465 /* Back up so we process the first insn in the extension. */
8466 insn = PREV_INSN (insn);
8470 if (next_qty > max_qty)
8473 /* If we are running before loop.c, we stopped on a NOTE_INSN_LOOP_END, and
8474 the previous insn is the only insn that branches to the head of a loop,
8475 we can cse into the loop. Don't do this if we changed the jump
8476 structure of a loop unless we aren't going to be following jumps. */
8478 if ((cse_jumps_altered == 0
8479 || (flag_cse_follow_jumps == 0 && flag_cse_skip_blocks == 0))
8480 && around_loop && to != 0
8481 && GET_CODE (to) == NOTE && NOTE_LINE_NUMBER (to) == NOTE_INSN_LOOP_END
8482 && GET_CODE (PREV_INSN (to)) == JUMP_INSN
8483 && JUMP_LABEL (PREV_INSN (to)) != 0
8484 && LABEL_NUSES (JUMP_LABEL (PREV_INSN (to))) == 1)
8485 cse_around_loop (JUMP_LABEL (PREV_INSN (to)));
8487 return to ? NEXT_INSN (to) : 0;
8490 /* Count the number of times registers are used (not set) in X.
8491 COUNTS is an array in which we accumulate the count, INCR is how much
8492 we count each register usage.
8494 Don't count a usage of DEST, which is the SET_DEST of a SET which
8495 contains X in its SET_SRC. This is because such a SET does not
8496 modify the liveness of DEST. */
8499 count_reg_usage (x, counts, dest, incr)
8512 switch (code = GET_CODE (x))
8516 counts[REGNO (x)] += incr;
8530 /* Unless we are setting a REG, count everything in SET_DEST. */
8531 if (GET_CODE (SET_DEST (x)) != REG)
8532 count_reg_usage (SET_DEST (x), counts, NULL_RTX, incr);
8534 /* If SRC has side-effects, then we can't delete this insn, so the
8535 usage of SET_DEST inside SRC counts.
8537 ??? Strictly-speaking, we might be preserving this insn
8538 because some other SET has side-effects, but that's hard
8539 to do and can't happen now. */
8540 count_reg_usage (SET_SRC (x), counts,
8541 side_effects_p (SET_SRC (x)) ? NULL_RTX : SET_DEST (x),
8546 count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, NULL_RTX, incr);
8548 /* ... falls through ... */
8551 count_reg_usage (PATTERN (x), counts, NULL_RTX, incr);
8553 /* Things used in a REG_EQUAL note aren't dead since loop may try to
8556 count_reg_usage (REG_NOTES (x), counts, NULL_RTX, incr);
8561 if (REG_NOTE_KIND (x) == REG_EQUAL
8562 || GET_CODE (XEXP (x,0)) == USE)
8563 count_reg_usage (XEXP (x, 0), counts, NULL_RTX, incr);
8564 count_reg_usage (XEXP (x, 1), counts, NULL_RTX, incr);
8568 fmt = GET_RTX_FORMAT (code);
8569 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
8572 count_reg_usage (XEXP (x, i), counts, dest, incr);
8573 else if (fmt[i] == 'E')
8574 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
8575 count_reg_usage (XVECEXP (x, i, j), counts, dest, incr);
8579 /* Scan all the insns and delete any that are dead; i.e., they store a register
8580 that is never used or they copy a register to itself.
8582 This is used to remove insns made obviously dead by cse. It improves the
8583 heuristics in loop since it won't try to move dead invariants out of loops
8584 or make givs for dead quantities. The remaining passes of the compilation
8585 are also sped up. */
8588 delete_dead_from_cse (insns, nreg)
8592 int *counts = (int *) alloca (nreg * sizeof (int));
8598 /* First count the number of times each register is used. */
8599 bzero ((char *) counts, sizeof (int) * nreg);
8600 for (insn = next_real_insn (insns); insn; insn = next_real_insn (insn))
8601 count_reg_usage (insn, counts, NULL_RTX, 1);
8603 /* Go from the last insn to the first and delete insns that only set unused
8604 registers or copy a register to itself. As we delete an insn, remove
8605 usage counts for registers it uses. */
8606 for (insn = prev_real_insn (get_last_insn ()); insn; insn = prev)
8610 prev = prev_real_insn (insn);
8612 /* Don't delete any insns that are part of a libcall block.
8613 Flow or loop might get confused if we did that. Remember
8614 that we are scanning backwards. */
8615 if (find_reg_note (insn, REG_RETVAL, NULL_RTX))
8620 else if (GET_CODE (PATTERN (insn)) == SET)
8622 if (GET_CODE (SET_DEST (PATTERN (insn))) == REG
8623 && SET_DEST (PATTERN (insn)) == SET_SRC (PATTERN (insn)))
8627 else if (GET_CODE (SET_DEST (PATTERN (insn))) == CC0
8628 && ! side_effects_p (SET_SRC (PATTERN (insn)))
8629 && ((tem = next_nonnote_insn (insn)) == 0
8630 || GET_RTX_CLASS (GET_CODE (tem)) != 'i'
8631 || ! reg_referenced_p (cc0_rtx, PATTERN (tem))))
8634 else if (GET_CODE (SET_DEST (PATTERN (insn))) != REG
8635 || REGNO (SET_DEST (PATTERN (insn))) < FIRST_PSEUDO_REGISTER
8636 || counts[REGNO (SET_DEST (PATTERN (insn)))] != 0
8637 || side_effects_p (SET_SRC (PATTERN (insn))))
8640 else if (GET_CODE (PATTERN (insn)) == PARALLEL)
8641 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
8643 rtx elt = XVECEXP (PATTERN (insn), 0, i);
8645 if (GET_CODE (elt) == SET)
8647 if (GET_CODE (SET_DEST (elt)) == REG
8648 && SET_DEST (elt) == SET_SRC (elt))
8652 else if (GET_CODE (SET_DEST (elt)) == CC0
8653 && ! side_effects_p (SET_SRC (elt))
8654 && ((tem = next_nonnote_insn (insn)) == 0
8655 || GET_RTX_CLASS (GET_CODE (tem)) != 'i'
8656 || ! reg_referenced_p (cc0_rtx, PATTERN (tem))))
8659 else if (GET_CODE (SET_DEST (elt)) != REG
8660 || REGNO (SET_DEST (elt)) < FIRST_PSEUDO_REGISTER
8661 || counts[REGNO (SET_DEST (elt))] != 0
8662 || side_effects_p (SET_SRC (elt)))
8665 else if (GET_CODE (elt) != CLOBBER && GET_CODE (elt) != USE)
8671 /* If this is a dead insn, delete it and show registers in it aren't
8676 count_reg_usage (insn, counts, NULL_RTX, -1);
8680 if (find_reg_note (insn, REG_LIBCALL, NULL_RTX))