1 /* Common subexpression elimination library for GNU compiler.
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
30 #include "hard-reg-set.h"
32 #include "insn-config.h"
36 #include "diagnostic-core.h"
40 #include "tree-pass.h"
43 #include "alloc-pool.h"
47 /* A list of cselib_val structures. */
49 struct elt_list
*next
;
53 static bool cselib_record_memory
;
54 static bool cselib_preserve_constants
;
55 static int entry_and_rtx_equal_p (const void *, const void *);
56 static hashval_t
get_value_hash (const void *);
57 static struct elt_list
*new_elt_list (struct elt_list
*, cselib_val
*);
58 static struct elt_loc_list
*new_elt_loc_list (struct elt_loc_list
*, rtx
);
59 static void unchain_one_value (cselib_val
*);
60 static void unchain_one_elt_list (struct elt_list
**);
61 static void unchain_one_elt_loc_list (struct elt_loc_list
**);
62 static int discard_useless_locs (void **, void *);
63 static int discard_useless_values (void **, void *);
64 static void remove_useless_values (void);
65 static int rtx_equal_for_cselib_1 (rtx
, rtx
, enum machine_mode
);
66 static unsigned int cselib_hash_rtx (rtx
, int, enum machine_mode
);
67 static cselib_val
*new_cselib_val (unsigned int, enum machine_mode
, rtx
);
68 static void add_mem_for_addr (cselib_val
*, cselib_val
*, rtx
);
69 static cselib_val
*cselib_lookup_mem (rtx
, int);
70 static void cselib_invalidate_regno (unsigned int, enum machine_mode
);
71 static void cselib_invalidate_mem (rtx
);
72 static void cselib_record_set (rtx
, cselib_val
*, cselib_val
*);
73 static void cselib_record_sets (rtx
);
75 struct expand_value_data
78 cselib_expand_callback callback
;
83 static rtx
cselib_expand_value_rtx_1 (rtx
, struct expand_value_data
*, int);
85 /* There are three ways in which cselib can look up an rtx:
86 - for a REG, the reg_values table (which is indexed by regno) is used
87 - for a MEM, we recursively look up its address and then follow the
88 addr_list of that value
89 - for everything else, we compute a hash value and go through the hash
90 table. Since different rtx's can still have the same hash value,
91 this involves walking the table entries for a given value and comparing
92 the locations of the entries with the rtx we are looking up. */
94 /* A table that enables us to look up elts by their value. */
95 static htab_t cselib_hash_table
;
97 /* This is a global so we don't have to pass this through every function.
98 It is used in new_elt_loc_list to set SETTING_INSN. */
99 static rtx cselib_current_insn
;
101 /* The unique id that the next create value will take. */
102 static unsigned int next_uid
;
104 /* The number of registers we had when the varrays were last resized. */
105 static unsigned int cselib_nregs
;
107 /* Count values without known locations, or with only locations that
108 wouldn't have been known except for debug insns. Whenever this
109 grows too big, we remove these useless values from the table.
111 Counting values with only debug values is a bit tricky. We don't
112 want to increment n_useless_values when we create a value for a
113 debug insn, for this would get n_useless_values out of sync, but we
114 want increment it if all locs in the list that were ever referenced
115 in nondebug insns are removed from the list.
117 In the general case, once we do that, we'd have to stop accepting
118 nondebug expressions in the loc list, to avoid having two values
119 equivalent that, without debug insns, would have been made into
120 separate values. However, because debug insns never introduce
121 equivalences themselves (no assignments), the only means for
122 growing loc lists is through nondebug assignments. If the locs
123 also happen to be referenced in debug insns, it will work just fine.
125 A consequence of this is that there's at most one debug-only loc in
126 each loc list. If we keep it in the first entry, testing whether
127 we have a debug-only loc list takes O(1).
129 Furthermore, since any additional entry in a loc list containing a
130 debug loc would have to come from an assignment (nondebug) that
131 references both the initial debug loc and the newly-equivalent loc,
132 the initial debug loc would be promoted to a nondebug loc, and the
133 loc list would not contain debug locs any more.
135 So the only case we have to be careful with in order to keep
136 n_useless_values in sync between debug and nondebug compilations is
137 to avoid incrementing n_useless_values when removing the single loc
138 from a value that turns out to not appear outside debug values. We
139 increment n_useless_debug_values instead, and leave such values
140 alone until, for other reasons, we garbage-collect useless
142 static int n_useless_values
;
143 static int n_useless_debug_values
;
145 /* Count values whose locs have been taken exclusively from debug
146 insns for the entire life of the value. */
147 static int n_debug_values
;
149 /* Number of useless values before we remove them from the hash table. */
150 #define MAX_USELESS_VALUES 32
152 /* This table maps from register number to values. It does not
153 contain pointers to cselib_val structures, but rather elt_lists.
154 The purpose is to be able to refer to the same register in
155 different modes. The first element of the list defines the mode in
156 which the register was set; if the mode is unknown or the value is
157 no longer valid in that mode, ELT will be NULL for the first
159 static struct elt_list
**reg_values
;
160 static unsigned int reg_values_size
;
161 #define REG_VALUES(i) reg_values[i]
163 /* The largest number of hard regs used by any entry added to the
164 REG_VALUES table. Cleared on each cselib_clear_table() invocation. */
165 static unsigned int max_value_regs
;
167 /* Here the set of indices I with REG_VALUES(I) != 0 is saved. This is used
168 in cselib_clear_table() for fast emptying. */
169 static unsigned int *used_regs
;
170 static unsigned int n_used_regs
;
172 /* We pass this to cselib_invalidate_mem to invalidate all of
173 memory for a non-const call instruction. */
174 static GTY(()) rtx callmem
;
176 /* Set by discard_useless_locs if it deleted the last location of any
178 static int values_became_useless
;
180 /* Used as stop element of the containing_mem list so we can check
181 presence in the list by checking the next pointer. */
182 static cselib_val dummy_val
;
184 /* If non-NULL, value of the eliminated arg_pointer_rtx or frame_pointer_rtx
185 that is constant through the whole function and should never be
187 static cselib_val
*cfa_base_preserved_val
;
188 static unsigned int cfa_base_preserved_regno
;
190 /* Used to list all values that contain memory reference.
191 May or may not contain the useless values - the list is compacted
192 each time memory is invalidated. */
193 static cselib_val
*first_containing_mem
= &dummy_val
;
194 static alloc_pool elt_loc_list_pool
, elt_list_pool
, cselib_val_pool
, value_pool
;
196 /* If nonnull, cselib will call this function before freeing useless
197 VALUEs. A VALUE is deemed useless if its "locs" field is null. */
198 void (*cselib_discard_hook
) (cselib_val
*);
200 /* If nonnull, cselib will call this function before recording sets or
201 even clobbering outputs of INSN. All the recorded sets will be
202 represented in the array sets[n_sets]. new_val_min can be used to
203 tell whether values present in sets are introduced by this
205 void (*cselib_record_sets_hook
) (rtx insn
, struct cselib_set
*sets
,
208 #define PRESERVED_VALUE_P(RTX) \
209 (RTL_FLAG_CHECK1("PRESERVED_VALUE_P", (RTX), VALUE)->unchanging)
213 /* Allocate a struct elt_list and fill in its two elements with the
216 static inline struct elt_list
*
217 new_elt_list (struct elt_list
*next
, cselib_val
*elt
)
220 el
= (struct elt_list
*) pool_alloc (elt_list_pool
);
226 /* Allocate a struct elt_loc_list and fill in its two elements with the
229 static inline struct elt_loc_list
*
230 new_elt_loc_list (struct elt_loc_list
*next
, rtx loc
)
232 struct elt_loc_list
*el
;
233 el
= (struct elt_loc_list
*) pool_alloc (elt_loc_list_pool
);
236 el
->setting_insn
= cselib_current_insn
;
237 gcc_assert (!next
|| !next
->setting_insn
238 || !DEBUG_INSN_P (next
->setting_insn
));
240 /* If we're creating the first loc in a debug insn context, we've
241 just created a debug value. Count it. */
242 if (!next
&& cselib_current_insn
&& DEBUG_INSN_P (cselib_current_insn
))
248 /* Promote loc L to a nondebug cselib_current_insn if L is marked as
249 originating from a debug insn, maintaining the debug values
253 promote_debug_loc (struct elt_loc_list
*l
)
255 if (l
->setting_insn
&& DEBUG_INSN_P (l
->setting_insn
)
256 && (!cselib_current_insn
|| !DEBUG_INSN_P (cselib_current_insn
)))
259 l
->setting_insn
= cselib_current_insn
;
260 gcc_assert (!l
->next
);
264 /* The elt_list at *PL is no longer needed. Unchain it and free its
268 unchain_one_elt_list (struct elt_list
**pl
)
270 struct elt_list
*l
= *pl
;
273 pool_free (elt_list_pool
, l
);
276 /* Likewise for elt_loc_lists. */
279 unchain_one_elt_loc_list (struct elt_loc_list
**pl
)
281 struct elt_loc_list
*l
= *pl
;
284 pool_free (elt_loc_list_pool
, l
);
287 /* Likewise for cselib_vals. This also frees the addr_list associated with
291 unchain_one_value (cselib_val
*v
)
294 unchain_one_elt_list (&v
->addr_list
);
296 pool_free (cselib_val_pool
, v
);
299 /* Remove all entries from the hash table. Also used during
303 cselib_clear_table (void)
305 cselib_reset_table (1);
308 /* Remove from hash table all VALUEs except constants. */
311 preserve_only_constants (void **x
, void *info ATTRIBUTE_UNUSED
)
313 cselib_val
*v
= (cselib_val
*)*x
;
316 && v
->locs
->next
== NULL
)
318 if (CONSTANT_P (v
->locs
->loc
)
319 && (GET_CODE (v
->locs
->loc
) != CONST
320 || !references_value_p (v
->locs
->loc
, 0)))
322 if (cfa_base_preserved_val
)
324 if (v
== cfa_base_preserved_val
)
326 if (GET_CODE (v
->locs
->loc
) == PLUS
327 && CONST_INT_P (XEXP (v
->locs
->loc
, 1))
328 && XEXP (v
->locs
->loc
, 0) == cfa_base_preserved_val
->val_rtx
)
333 htab_clear_slot (cselib_hash_table
, x
);
337 /* Remove all entries from the hash table, arranging for the next
338 value to be numbered NUM. */
341 cselib_reset_table (unsigned int num
)
347 if (cfa_base_preserved_val
)
349 unsigned int regno
= cfa_base_preserved_regno
;
350 unsigned int new_used_regs
= 0;
351 for (i
= 0; i
< n_used_regs
; i
++)
352 if (used_regs
[i
] == regno
)
358 REG_VALUES (used_regs
[i
]) = 0;
359 gcc_assert (new_used_regs
== 1);
360 n_used_regs
= new_used_regs
;
361 used_regs
[0] = regno
;
363 = hard_regno_nregs
[regno
][GET_MODE (cfa_base_preserved_val
->locs
->loc
)];
367 for (i
= 0; i
< n_used_regs
; i
++)
368 REG_VALUES (used_regs
[i
]) = 0;
372 if (cselib_preserve_constants
)
373 htab_traverse (cselib_hash_table
, preserve_only_constants
, NULL
);
375 htab_empty (cselib_hash_table
);
377 n_useless_values
= 0;
378 n_useless_debug_values
= 0;
383 first_containing_mem
= &dummy_val
;
386 /* Return the number of the next value that will be generated. */
389 cselib_get_next_uid (void)
394 /* See the documentation of cselib_find_slot below. */
395 static enum machine_mode find_slot_memmode
;
397 /* Search for X, whose hashcode is HASH, in CSELIB_HASH_TABLE,
398 INSERTing if requested. When X is part of the address of a MEM,
399 MEMMODE should specify the mode of the MEM. While searching the
400 table, MEMMODE is held in FIND_SLOT_MEMMODE, so that autoinc RTXs
401 in X can be resolved. */
404 cselib_find_slot (rtx x
, hashval_t hash
, enum insert_option insert
,
405 enum machine_mode memmode
)
408 find_slot_memmode
= memmode
;
409 slot
= htab_find_slot_with_hash (cselib_hash_table
, x
, hash
, insert
);
410 find_slot_memmode
= VOIDmode
;
414 /* The equality test for our hash table. The first argument ENTRY is a table
415 element (i.e. a cselib_val), while the second arg X is an rtx. We know
416 that all callers of htab_find_slot_with_hash will wrap CONST_INTs into a
417 CONST of an appropriate mode. */
420 entry_and_rtx_equal_p (const void *entry
, const void *x_arg
)
422 struct elt_loc_list
*l
;
423 const cselib_val
*const v
= (const cselib_val
*) entry
;
424 rtx x
= CONST_CAST_RTX ((const_rtx
)x_arg
);
425 enum machine_mode mode
= GET_MODE (x
);
427 gcc_assert (!CONST_INT_P (x
) && GET_CODE (x
) != CONST_FIXED
428 && (mode
!= VOIDmode
|| GET_CODE (x
) != CONST_DOUBLE
));
430 if (mode
!= GET_MODE (v
->val_rtx
))
433 /* Unwrap X if necessary. */
434 if (GET_CODE (x
) == CONST
435 && (CONST_INT_P (XEXP (x
, 0))
436 || GET_CODE (XEXP (x
, 0)) == CONST_FIXED
437 || GET_CODE (XEXP (x
, 0)) == CONST_DOUBLE
))
440 /* We don't guarantee that distinct rtx's have different hash values,
441 so we need to do a comparison. */
442 for (l
= v
->locs
; l
; l
= l
->next
)
443 if (rtx_equal_for_cselib_1 (l
->loc
, x
, find_slot_memmode
))
445 promote_debug_loc (l
);
452 /* The hash function for our hash table. The value is always computed with
453 cselib_hash_rtx when adding an element; this function just extracts the
454 hash value from a cselib_val structure. */
457 get_value_hash (const void *entry
)
459 const cselib_val
*const v
= (const cselib_val
*) entry
;
463 /* Return true if X contains a VALUE rtx. If ONLY_USELESS is set, we
464 only return true for values which point to a cselib_val whose value
465 element has been set to zero, which implies the cselib_val will be
469 references_value_p (const_rtx x
, int only_useless
)
471 const enum rtx_code code
= GET_CODE (x
);
472 const char *fmt
= GET_RTX_FORMAT (code
);
475 if (GET_CODE (x
) == VALUE
476 && (! only_useless
|| CSELIB_VAL_PTR (x
)->locs
== 0))
479 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
481 if (fmt
[i
] == 'e' && references_value_p (XEXP (x
, i
), only_useless
))
483 else if (fmt
[i
] == 'E')
484 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
485 if (references_value_p (XVECEXP (x
, i
, j
), only_useless
))
492 /* For all locations found in X, delete locations that reference useless
493 values (i.e. values without any location). Called through
497 discard_useless_locs (void **x
, void *info ATTRIBUTE_UNUSED
)
499 cselib_val
*v
= (cselib_val
*)*x
;
500 struct elt_loc_list
**p
= &v
->locs
;
501 bool had_locs
= v
->locs
!= NULL
;
502 rtx setting_insn
= v
->locs
? v
->locs
->setting_insn
: NULL
;
506 if (references_value_p ((*p
)->loc
, 1))
507 unchain_one_elt_loc_list (p
);
512 if (had_locs
&& v
->locs
== 0 && !PRESERVED_VALUE_P (v
->val_rtx
))
514 if (setting_insn
&& DEBUG_INSN_P (setting_insn
))
515 n_useless_debug_values
++;
518 values_became_useless
= 1;
523 /* If X is a value with no locations, remove it from the hashtable. */
526 discard_useless_values (void **x
, void *info ATTRIBUTE_UNUSED
)
528 cselib_val
*v
= (cselib_val
*)*x
;
530 if (v
->locs
== 0 && !PRESERVED_VALUE_P (v
->val_rtx
))
532 if (cselib_discard_hook
)
533 cselib_discard_hook (v
);
535 CSELIB_VAL_PTR (v
->val_rtx
) = NULL
;
536 htab_clear_slot (cselib_hash_table
, x
);
537 unchain_one_value (v
);
544 /* Clean out useless values (i.e. those which no longer have locations
545 associated with them) from the hash table. */
548 remove_useless_values (void)
552 /* First pass: eliminate locations that reference the value. That in
553 turn can make more values useless. */
556 values_became_useless
= 0;
557 htab_traverse (cselib_hash_table
, discard_useless_locs
, 0);
559 while (values_became_useless
);
561 /* Second pass: actually remove the values. */
563 p
= &first_containing_mem
;
564 for (v
= *p
; v
!= &dummy_val
; v
= v
->next_containing_mem
)
568 p
= &(*p
)->next_containing_mem
;
572 n_useless_values
+= n_useless_debug_values
;
573 n_debug_values
-= n_useless_debug_values
;
574 n_useless_debug_values
= 0;
576 htab_traverse (cselib_hash_table
, discard_useless_values
, 0);
578 gcc_assert (!n_useless_values
);
581 /* Arrange for a value to not be removed from the hash table even if
582 it becomes useless. */
585 cselib_preserve_value (cselib_val
*v
)
587 PRESERVED_VALUE_P (v
->val_rtx
) = 1;
590 /* Test whether a value is preserved. */
593 cselib_preserved_value_p (cselib_val
*v
)
595 return PRESERVED_VALUE_P (v
->val_rtx
);
598 /* Arrange for a REG value to be assumed constant through the whole function,
599 never invalidated and preserved across cselib_reset_table calls. */
602 cselib_preserve_cfa_base_value (cselib_val
*v
, unsigned int regno
)
604 if (cselib_preserve_constants
606 && REG_P (v
->locs
->loc
))
608 cfa_base_preserved_val
= v
;
609 cfa_base_preserved_regno
= regno
;
613 /* Clean all non-constant expressions in the hash table, but retain
617 cselib_preserve_only_values (void)
621 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
622 cselib_invalidate_regno (i
, reg_raw_mode
[i
]);
624 cselib_invalidate_mem (callmem
);
626 remove_useless_values ();
628 gcc_assert (first_containing_mem
== &dummy_val
);
631 /* Return the mode in which a register was last set. If X is not a
632 register, return its mode. If the mode in which the register was
633 set is not known, or the value was already clobbered, return
637 cselib_reg_set_mode (const_rtx x
)
642 if (REG_VALUES (REGNO (x
)) == NULL
643 || REG_VALUES (REGNO (x
))->elt
== NULL
)
646 return GET_MODE (REG_VALUES (REGNO (x
))->elt
->val_rtx
);
649 /* Return nonzero if we can prove that X and Y contain the same value, taking
650 our gathered information into account. */
653 rtx_equal_for_cselib_p (rtx x
, rtx y
)
655 return rtx_equal_for_cselib_1 (x
, y
, VOIDmode
);
658 /* If x is a PLUS or an autoinc operation, expand the operation,
659 storing the offset, if any, in *OFF. */
662 autoinc_split (rtx x
, rtx
*off
, enum machine_mode memmode
)
664 switch (GET_CODE (x
))
671 if (memmode
== VOIDmode
)
674 *off
= GEN_INT (-GET_MODE_SIZE (memmode
));
679 if (memmode
== VOIDmode
)
682 *off
= GEN_INT (GET_MODE_SIZE (memmode
));
698 /* Return nonzero if we can prove that X and Y contain the same value,
699 taking our gathered information into account. MEMMODE holds the
700 mode of the enclosing MEM, if any, as required to deal with autoinc
701 addressing modes. If X and Y are not (known to be) part of
702 addresses, MEMMODE should be VOIDmode. */
705 rtx_equal_for_cselib_1 (rtx x
, rtx y
, enum machine_mode memmode
)
711 if (REG_P (x
) || MEM_P (x
))
713 cselib_val
*e
= cselib_lookup (x
, GET_MODE (x
), 0, memmode
);
719 if (REG_P (y
) || MEM_P (y
))
721 cselib_val
*e
= cselib_lookup (y
, GET_MODE (y
), 0, memmode
);
730 if (GET_CODE (x
) == VALUE
&& GET_CODE (y
) == VALUE
)
731 return CSELIB_VAL_PTR (x
) == CSELIB_VAL_PTR (y
);
733 if (GET_CODE (x
) == VALUE
)
735 cselib_val
*e
= CSELIB_VAL_PTR (x
);
736 struct elt_loc_list
*l
;
738 for (l
= e
->locs
; l
; l
= l
->next
)
742 /* Avoid infinite recursion. */
743 if (REG_P (t
) || MEM_P (t
))
745 else if (rtx_equal_for_cselib_1 (t
, y
, memmode
))
752 if (GET_CODE (y
) == VALUE
)
754 cselib_val
*e
= CSELIB_VAL_PTR (y
);
755 struct elt_loc_list
*l
;
757 for (l
= e
->locs
; l
; l
= l
->next
)
761 if (REG_P (t
) || MEM_P (t
))
763 else if (rtx_equal_for_cselib_1 (x
, t
, memmode
))
770 if (GET_MODE (x
) != GET_MODE (y
))
773 if (GET_CODE (x
) != GET_CODE (y
))
775 rtx xorig
= x
, yorig
= y
;
776 rtx xoff
= NULL
, yoff
= NULL
;
778 x
= autoinc_split (x
, &xoff
, memmode
);
779 y
= autoinc_split (y
, &yoff
, memmode
);
784 if (xoff
&& !rtx_equal_for_cselib_1 (xoff
, yoff
, memmode
))
787 /* Don't recurse if nothing changed. */
788 if (x
!= xorig
|| y
!= yorig
)
789 return rtx_equal_for_cselib_1 (x
, y
, memmode
);
794 /* These won't be handled correctly by the code below. */
795 switch (GET_CODE (x
))
802 case DEBUG_IMPLICIT_PTR
:
803 return DEBUG_IMPLICIT_PTR_DECL (x
)
804 == DEBUG_IMPLICIT_PTR_DECL (y
);
807 return XEXP (x
, 0) == XEXP (y
, 0);
810 /* We have to compare any autoinc operations in the addresses
811 using this MEM's mode. */
812 return rtx_equal_for_cselib_1 (XEXP (x
, 0), XEXP (y
, 0), GET_MODE (x
));
819 fmt
= GET_RTX_FORMAT (code
);
821 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
828 if (XWINT (x
, i
) != XWINT (y
, i
))
834 if (XINT (x
, i
) != XINT (y
, i
))
840 /* Two vectors must have the same length. */
841 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
844 /* And the corresponding elements must match. */
845 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
846 if (! rtx_equal_for_cselib_1 (XVECEXP (x
, i
, j
),
847 XVECEXP (y
, i
, j
), memmode
))
853 && targetm
.commutative_p (x
, UNKNOWN
)
854 && rtx_equal_for_cselib_1 (XEXP (x
, 1), XEXP (y
, 0), memmode
)
855 && rtx_equal_for_cselib_1 (XEXP (x
, 0), XEXP (y
, 1), memmode
))
857 if (! rtx_equal_for_cselib_1 (XEXP (x
, i
), XEXP (y
, i
), memmode
))
863 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
868 /* These are just backpointers, so they don't matter. */
875 /* It is believed that rtx's at this level will never
876 contain anything but integers and other rtx's,
877 except for within LABEL_REFs and SYMBOL_REFs. */
885 /* We need to pass down the mode of constants through the hash table
886 functions. For that purpose, wrap them in a CONST of the appropriate
889 wrap_constant (enum machine_mode mode
, rtx x
)
891 if (!CONST_INT_P (x
) && GET_CODE (x
) != CONST_FIXED
892 && (GET_CODE (x
) != CONST_DOUBLE
|| GET_MODE (x
) != VOIDmode
))
894 gcc_assert (mode
!= VOIDmode
);
895 return gen_rtx_CONST (mode
, x
);
898 /* Hash an rtx. Return 0 if we couldn't hash the rtx.
899 For registers and memory locations, we look up their cselib_val structure
900 and return its VALUE element.
901 Possible reasons for return 0 are: the object is volatile, or we couldn't
902 find a register or memory location in the table and CREATE is zero. If
903 CREATE is nonzero, table elts are created for regs and mem.
904 N.B. this hash function returns the same hash value for RTXes that
905 differ only in the order of operands, thus it is suitable for comparisons
906 that take commutativity into account.
907 If we wanted to also support associative rules, we'd have to use a different
908 strategy to avoid returning spurious 0, e.g. return ~(~0U >> 1) .
909 MEMMODE indicates the mode of an enclosing MEM, and it's only
910 used to compute autoinc values.
911 We used to have a MODE argument for hashing for CONST_INTs, but that
912 didn't make sense, since it caused spurious hash differences between
913 (set (reg:SI 1) (const_int))
914 (plus:SI (reg:SI 2) (reg:SI 1))
916 (plus:SI (reg:SI 2) (const_int))
917 If the mode is important in any context, it must be checked specifically
918 in a comparison anyway, since relying on hash differences is unsafe. */
921 cselib_hash_rtx (rtx x
, int create
, enum machine_mode memmode
)
927 unsigned int hash
= 0;
930 hash
+= (unsigned) code
+ (unsigned) GET_MODE (x
);
936 e
= cselib_lookup (x
, GET_MODE (x
), create
, memmode
);
943 hash
+= ((unsigned) DEBUG_EXPR
<< 7)
944 + DEBUG_TEMP_UID (DEBUG_EXPR_TREE_DECL (x
));
945 return hash
? hash
: (unsigned int) DEBUG_EXPR
;
947 case DEBUG_IMPLICIT_PTR
:
948 hash
+= ((unsigned) DEBUG_IMPLICIT_PTR
<< 7)
949 + DECL_UID (DEBUG_IMPLICIT_PTR_DECL (x
));
950 return hash
? hash
: (unsigned int) DEBUG_IMPLICIT_PTR
;
953 hash
+= ((unsigned) CONST_INT
<< 7) + INTVAL (x
);
954 return hash
? hash
: (unsigned int) CONST_INT
;
957 /* This is like the general case, except that it only counts
958 the integers representing the constant. */
959 hash
+= (unsigned) code
+ (unsigned) GET_MODE (x
);
960 if (GET_MODE (x
) != VOIDmode
)
961 hash
+= real_hash (CONST_DOUBLE_REAL_VALUE (x
));
963 hash
+= ((unsigned) CONST_DOUBLE_LOW (x
)
964 + (unsigned) CONST_DOUBLE_HIGH (x
));
965 return hash
? hash
: (unsigned int) CONST_DOUBLE
;
968 hash
+= (unsigned int) code
+ (unsigned int) GET_MODE (x
);
969 hash
+= fixed_hash (CONST_FIXED_VALUE (x
));
970 return hash
? hash
: (unsigned int) CONST_FIXED
;
977 units
= CONST_VECTOR_NUNITS (x
);
979 for (i
= 0; i
< units
; ++i
)
981 elt
= CONST_VECTOR_ELT (x
, i
);
982 hash
+= cselib_hash_rtx (elt
, 0, memmode
);
988 /* Assume there is only one rtx object for any given label. */
990 /* We don't hash on the address of the CODE_LABEL to avoid bootstrap
991 differences and differences between each stage's debugging dumps. */
992 hash
+= (((unsigned int) LABEL_REF
<< 7)
993 + CODE_LABEL_NUMBER (XEXP (x
, 0)));
994 return hash
? hash
: (unsigned int) LABEL_REF
;
998 /* Don't hash on the symbol's address to avoid bootstrap differences.
999 Different hash values may cause expressions to be recorded in
1000 different orders and thus different registers to be used in the
1001 final assembler. This also avoids differences in the dump files
1002 between various stages. */
1004 const unsigned char *p
= (const unsigned char *) XSTR (x
, 0);
1007 h
+= (h
<< 7) + *p
++; /* ??? revisit */
1009 hash
+= ((unsigned int) SYMBOL_REF
<< 7) + h
;
1010 return hash
? hash
: (unsigned int) SYMBOL_REF
;
1015 /* We can't compute these without knowing the MEM mode. */
1016 gcc_assert (memmode
!= VOIDmode
);
1017 i
= GET_MODE_SIZE (memmode
);
1018 if (code
== PRE_DEC
)
1020 /* Adjust the hash so that (mem:MEMMODE (pre_* (reg))) hashes
1021 like (mem:MEMMODE (plus (reg) (const_int I))). */
1022 hash
+= (unsigned) PLUS
- (unsigned)code
1023 + cselib_hash_rtx (XEXP (x
, 0), create
, memmode
)
1024 + cselib_hash_rtx (GEN_INT (i
), create
, memmode
);
1025 return hash
? hash
: 1 + (unsigned) PLUS
;
1028 gcc_assert (memmode
!= VOIDmode
);
1029 return cselib_hash_rtx (XEXP (x
, 1), create
, memmode
);
1034 gcc_assert (memmode
!= VOIDmode
);
1035 return cselib_hash_rtx (XEXP (x
, 0), create
, memmode
);
1040 case UNSPEC_VOLATILE
:
1044 if (MEM_VOLATILE_P (x
))
1053 i
= GET_RTX_LENGTH (code
) - 1;
1054 fmt
= GET_RTX_FORMAT (code
);
1061 rtx tem
= XEXP (x
, i
);
1062 unsigned int tem_hash
= cselib_hash_rtx (tem
, create
, memmode
);
1071 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1073 unsigned int tem_hash
1074 = cselib_hash_rtx (XVECEXP (x
, i
, j
), create
, memmode
);
1085 const unsigned char *p
= (const unsigned char *) XSTR (x
, i
);
1094 hash
+= XINT (x
, i
);
1107 return hash
? hash
: 1 + (unsigned int) GET_CODE (x
);
1110 /* Create a new value structure for VALUE and initialize it. The mode of the
1113 static inline cselib_val
*
1114 new_cselib_val (unsigned int hash
, enum machine_mode mode
, rtx x
)
1116 cselib_val
*e
= (cselib_val
*) pool_alloc (cselib_val_pool
);
1119 gcc_assert (next_uid
);
1122 e
->uid
= next_uid
++;
1123 /* We use an alloc pool to allocate this RTL construct because it
1124 accounts for about 8% of the overall memory usage. We know
1125 precisely when we can have VALUE RTXen (when cselib is active)
1126 so we don't need to put them in garbage collected memory.
1127 ??? Why should a VALUE be an RTX in the first place? */
1128 e
->val_rtx
= (rtx
) pool_alloc (value_pool
);
1129 memset (e
->val_rtx
, 0, RTX_HDR_SIZE
);
1130 PUT_CODE (e
->val_rtx
, VALUE
);
1131 PUT_MODE (e
->val_rtx
, mode
);
1132 CSELIB_VAL_PTR (e
->val_rtx
) = e
;
1135 e
->next_containing_mem
= 0;
1137 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1139 fprintf (dump_file
, "cselib value %u:%u ", e
->uid
, hash
);
1140 if (flag_dump_noaddr
|| flag_dump_unnumbered
)
1141 fputs ("# ", dump_file
);
1143 fprintf (dump_file
, "%p ", (void*)e
);
1144 print_rtl_single (dump_file
, x
);
1145 fputc ('\n', dump_file
);
1151 /* ADDR_ELT is a value that is used as address. MEM_ELT is the value that
1152 contains the data at this address. X is a MEM that represents the
1153 value. Update the two value structures to represent this situation. */
1156 add_mem_for_addr (cselib_val
*addr_elt
, cselib_val
*mem_elt
, rtx x
)
1158 struct elt_loc_list
*l
;
1160 /* Avoid duplicates. */
1161 for (l
= mem_elt
->locs
; l
; l
= l
->next
)
1163 && CSELIB_VAL_PTR (XEXP (l
->loc
, 0)) == addr_elt
)
1165 promote_debug_loc (l
);
1169 addr_elt
->addr_list
= new_elt_list (addr_elt
->addr_list
, mem_elt
);
1171 = new_elt_loc_list (mem_elt
->locs
,
1172 replace_equiv_address_nv (x
, addr_elt
->val_rtx
));
1173 if (mem_elt
->next_containing_mem
== NULL
)
1175 mem_elt
->next_containing_mem
= first_containing_mem
;
1176 first_containing_mem
= mem_elt
;
1180 /* Subroutine of cselib_lookup. Return a value for X, which is a MEM rtx.
1181 If CREATE, make a new one if we haven't seen it before. */
1184 cselib_lookup_mem (rtx x
, int create
)
1186 enum machine_mode mode
= GET_MODE (x
);
1187 enum machine_mode addr_mode
;
1190 cselib_val
*mem_elt
;
1193 if (MEM_VOLATILE_P (x
) || mode
== BLKmode
1194 || !cselib_record_memory
1195 || (FLOAT_MODE_P (mode
) && flag_float_store
))
1198 addr_mode
= GET_MODE (XEXP (x
, 0));
1199 if (addr_mode
== VOIDmode
)
1202 /* Look up the value for the address. */
1203 addr
= cselib_lookup (XEXP (x
, 0), addr_mode
, create
, mode
);
1207 /* Find a value that describes a value of our mode at that address. */
1208 for (l
= addr
->addr_list
; l
; l
= l
->next
)
1209 if (GET_MODE (l
->elt
->val_rtx
) == mode
)
1211 promote_debug_loc (l
->elt
->locs
);
1218 mem_elt
= new_cselib_val (next_uid
, mode
, x
);
1219 add_mem_for_addr (addr
, mem_elt
, x
);
1220 slot
= cselib_find_slot (wrap_constant (mode
, x
), mem_elt
->hash
,
1226 /* Search thru the possible substitutions in P. We prefer a non reg
1227 substitution because this allows us to expand the tree further. If
1228 we find, just a reg, take the lowest regno. There may be several
1229 non-reg results, we just take the first one because they will all
1230 expand to the same place. */
1233 expand_loc (struct elt_loc_list
*p
, struct expand_value_data
*evd
,
1236 rtx reg_result
= NULL
;
1237 unsigned int regno
= UINT_MAX
;
1238 struct elt_loc_list
*p_in
= p
;
1240 for (; p
; p
= p
-> next
)
1242 /* Avoid infinite recursion trying to expand a reg into a
1244 if ((REG_P (p
->loc
))
1245 && (REGNO (p
->loc
) < regno
)
1246 && !bitmap_bit_p (evd
->regs_active
, REGNO (p
->loc
)))
1248 reg_result
= p
->loc
;
1249 regno
= REGNO (p
->loc
);
1251 /* Avoid infinite recursion and do not try to expand the
1253 else if (GET_CODE (p
->loc
) == VALUE
1254 && CSELIB_VAL_PTR (p
->loc
)->locs
== p_in
)
1256 else if (!REG_P (p
->loc
))
1259 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1261 print_inline_rtx (dump_file
, p
->loc
, 0);
1262 fprintf (dump_file
, "\n");
1264 if (GET_CODE (p
->loc
) == LO_SUM
1265 && GET_CODE (XEXP (p
->loc
, 1)) == SYMBOL_REF
1267 && (note
= find_reg_note (p
->setting_insn
, REG_EQUAL
, NULL_RTX
))
1268 && XEXP (note
, 0) == XEXP (p
->loc
, 1))
1269 return XEXP (p
->loc
, 1);
1270 result
= cselib_expand_value_rtx_1 (p
->loc
, evd
, max_depth
- 1);
1277 if (regno
!= UINT_MAX
)
1280 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1281 fprintf (dump_file
, "r%d\n", regno
);
1283 result
= cselib_expand_value_rtx_1 (reg_result
, evd
, max_depth
- 1);
1288 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1292 print_inline_rtx (dump_file
, reg_result
, 0);
1293 fprintf (dump_file
, "\n");
1296 fprintf (dump_file
, "NULL\n");
1302 /* Forward substitute and expand an expression out to its roots.
1303 This is the opposite of common subexpression. Because local value
1304 numbering is such a weak optimization, the expanded expression is
1305 pretty much unique (not from a pointer equals point of view but
1306 from a tree shape point of view.
1308 This function returns NULL if the expansion fails. The expansion
1309 will fail if there is no value number for one of the operands or if
1310 one of the operands has been overwritten between the current insn
1311 and the beginning of the basic block. For instance x has no
1317 REGS_ACTIVE is a scratch bitmap that should be clear when passing in.
1318 It is clear on return. */
1321 cselib_expand_value_rtx (rtx orig
, bitmap regs_active
, int max_depth
)
1323 struct expand_value_data evd
;
1325 evd
.regs_active
= regs_active
;
1326 evd
.callback
= NULL
;
1327 evd
.callback_arg
= NULL
;
1330 return cselib_expand_value_rtx_1 (orig
, &evd
, max_depth
);
1333 /* Same as cselib_expand_value_rtx, but using a callback to try to
1334 resolve some expressions. The CB function should return ORIG if it
1335 can't or does not want to deal with a certain RTX. Any other
1336 return value, including NULL, will be used as the expansion for
1337 VALUE, without any further changes. */
1340 cselib_expand_value_rtx_cb (rtx orig
, bitmap regs_active
, int max_depth
,
1341 cselib_expand_callback cb
, void *data
)
1343 struct expand_value_data evd
;
1345 evd
.regs_active
= regs_active
;
1347 evd
.callback_arg
= data
;
1350 return cselib_expand_value_rtx_1 (orig
, &evd
, max_depth
);
1353 /* Similar to cselib_expand_value_rtx_cb, but no rtxs are actually copied
1354 or simplified. Useful to find out whether cselib_expand_value_rtx_cb
1355 would return NULL or non-NULL, without allocating new rtx. */
1358 cselib_dummy_expand_value_rtx_cb (rtx orig
, bitmap regs_active
, int max_depth
,
1359 cselib_expand_callback cb
, void *data
)
1361 struct expand_value_data evd
;
1363 evd
.regs_active
= regs_active
;
1365 evd
.callback_arg
= data
;
1368 return cselib_expand_value_rtx_1 (orig
, &evd
, max_depth
) != NULL
;
1371 /* Internal implementation of cselib_expand_value_rtx and
1372 cselib_expand_value_rtx_cb. */
1375 cselib_expand_value_rtx_1 (rtx orig
, struct expand_value_data
*evd
,
1381 const char *format_ptr
;
1382 enum machine_mode mode
;
1384 code
= GET_CODE (orig
);
1386 /* For the context of dse, if we end up expand into a huge tree, we
1387 will not have a useful address, so we might as well just give up
1396 struct elt_list
*l
= REG_VALUES (REGNO (orig
));
1398 if (l
&& l
->elt
== NULL
)
1400 for (; l
; l
= l
->next
)
1401 if (GET_MODE (l
->elt
->val_rtx
) == GET_MODE (orig
))
1404 int regno
= REGNO (orig
);
1406 /* The only thing that we are not willing to do (this
1407 is requirement of dse and if others potential uses
1408 need this function we should add a parm to control
1409 it) is that we will not substitute the
1410 STACK_POINTER_REGNUM, FRAME_POINTER or the
1413 These expansions confuses the code that notices that
1414 stores into the frame go dead at the end of the
1415 function and that the frame is not effected by calls
1416 to subroutines. If you allow the
1417 STACK_POINTER_REGNUM substitution, then dse will
1418 think that parameter pushing also goes dead which is
1419 wrong. If you allow the FRAME_POINTER or the
1420 HARD_FRAME_POINTER then you lose the opportunity to
1421 make the frame assumptions. */
1422 if (regno
== STACK_POINTER_REGNUM
1423 || regno
== FRAME_POINTER_REGNUM
1424 || regno
== HARD_FRAME_POINTER_REGNUM
)
1427 bitmap_set_bit (evd
->regs_active
, regno
);
1429 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1430 fprintf (dump_file
, "expanding: r%d into: ", regno
);
1432 result
= expand_loc (l
->elt
->locs
, evd
, max_depth
);
1433 bitmap_clear_bit (evd
->regs_active
, regno
);
1450 /* SCRATCH must be shared because they represent distinct values. */
1453 if (REG_P (XEXP (orig
, 0)) && HARD_REGISTER_NUM_P (REGNO (XEXP (orig
, 0))))
1458 if (shared_const_p (orig
))
1468 subreg
= evd
->callback (orig
, evd
->regs_active
, max_depth
,
1474 subreg
= cselib_expand_value_rtx_1 (SUBREG_REG (orig
), evd
,
1478 scopy
= simplify_gen_subreg (GET_MODE (orig
), subreg
,
1479 GET_MODE (SUBREG_REG (orig
)),
1480 SUBREG_BYTE (orig
));
1482 || (GET_CODE (scopy
) == SUBREG
1483 && !REG_P (SUBREG_REG (scopy
))
1484 && !MEM_P (SUBREG_REG (scopy
))))
1494 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1496 fputs ("\nexpanding ", dump_file
);
1497 print_rtl_single (dump_file
, orig
);
1498 fputs (" into...", dump_file
);
1503 result
= evd
->callback (orig
, evd
->regs_active
, max_depth
,
1510 result
= expand_loc (CSELIB_VAL_PTR (orig
)->locs
, evd
, max_depth
);
1516 return evd
->callback (orig
, evd
->regs_active
, max_depth
,
1524 /* Copy the various flags, fields, and other information. We assume
1525 that all fields need copying, and then clear the fields that should
1526 not be copied. That is the sensible default behavior, and forces
1527 us to explicitly document why we are *not* copying a flag. */
1531 copy
= shallow_copy_rtx (orig
);
1533 format_ptr
= GET_RTX_FORMAT (code
);
1535 for (i
= 0; i
< GET_RTX_LENGTH (code
); i
++)
1536 switch (*format_ptr
++)
1539 if (XEXP (orig
, i
) != NULL
)
1541 rtx result
= cselib_expand_value_rtx_1 (XEXP (orig
, i
), evd
,
1546 XEXP (copy
, i
) = result
;
1552 if (XVEC (orig
, i
) != NULL
)
1555 XVEC (copy
, i
) = rtvec_alloc (XVECLEN (orig
, i
));
1556 for (j
= 0; j
< XVECLEN (orig
, i
); j
++)
1558 rtx result
= cselib_expand_value_rtx_1 (XVECEXP (orig
, i
, j
),
1559 evd
, max_depth
- 1);
1563 XVECEXP (copy
, i
, j
) = result
;
1577 /* These are left unchanged. */
1587 mode
= GET_MODE (copy
);
1588 /* If an operand has been simplified into CONST_INT, which doesn't
1589 have a mode and the mode isn't derivable from whole rtx's mode,
1590 try simplify_*_operation first with mode from original's operand
1591 and as a fallback wrap CONST_INT into gen_rtx_CONST. */
1593 switch (GET_RTX_CLASS (code
))
1596 if (CONST_INT_P (XEXP (copy
, 0))
1597 && GET_MODE (XEXP (orig
, 0)) != VOIDmode
)
1599 scopy
= simplify_unary_operation (code
, mode
, XEXP (copy
, 0),
1600 GET_MODE (XEXP (orig
, 0)));
1605 case RTX_COMM_ARITH
:
1607 /* These expressions can derive operand modes from the whole rtx's mode. */
1610 case RTX_BITFIELD_OPS
:
1611 if (CONST_INT_P (XEXP (copy
, 0))
1612 && GET_MODE (XEXP (orig
, 0)) != VOIDmode
)
1614 scopy
= simplify_ternary_operation (code
, mode
,
1615 GET_MODE (XEXP (orig
, 0)),
1616 XEXP (copy
, 0), XEXP (copy
, 1),
1623 case RTX_COMM_COMPARE
:
1624 if (CONST_INT_P (XEXP (copy
, 0))
1625 && GET_MODE (XEXP (copy
, 1)) == VOIDmode
1626 && (GET_MODE (XEXP (orig
, 0)) != VOIDmode
1627 || GET_MODE (XEXP (orig
, 1)) != VOIDmode
))
1629 scopy
= simplify_relational_operation (code
, mode
,
1630 (GET_MODE (XEXP (orig
, 0))
1632 ? GET_MODE (XEXP (orig
, 0))
1633 : GET_MODE (XEXP (orig
, 1)),
1643 scopy
= simplify_rtx (copy
);
1649 /* Walk rtx X and replace all occurrences of REG and MEM subexpressions
1650 with VALUE expressions. This way, it becomes independent of changes
1651 to registers and memory.
1652 X isn't actually modified; if modifications are needed, new rtl is
1653 allocated. However, the return value can share rtl with X.
1654 If X is within a MEM, MEMMODE must be the mode of the MEM. */
1657 cselib_subst_to_values (rtx x
, enum machine_mode memmode
)
1659 enum rtx_code code
= GET_CODE (x
);
1660 const char *fmt
= GET_RTX_FORMAT (code
);
1669 l
= REG_VALUES (REGNO (x
));
1670 if (l
&& l
->elt
== NULL
)
1672 for (; l
; l
= l
->next
)
1673 if (GET_MODE (l
->elt
->val_rtx
) == GET_MODE (x
))
1674 return l
->elt
->val_rtx
;
1679 e
= cselib_lookup_mem (x
, 0);
1680 /* This used to happen for autoincrements, but we deal with them
1681 properly now. Remove the if stmt for the next release. */
1684 /* Assign a value that doesn't match any other. */
1685 e
= new_cselib_val (next_uid
, GET_MODE (x
), x
);
1697 gcc_assert (memmode
!= VOIDmode
);
1698 i
= GET_MODE_SIZE (memmode
);
1699 if (code
== PRE_DEC
)
1701 return cselib_subst_to_values (plus_constant (XEXP (x
, 0), i
),
1705 gcc_assert (memmode
!= VOIDmode
);
1706 return cselib_subst_to_values (XEXP (x
, 1), memmode
);
1711 gcc_assert (memmode
!= VOIDmode
);
1712 return cselib_subst_to_values (XEXP (x
, 0), memmode
);
1718 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1722 rtx t
= cselib_subst_to_values (XEXP (x
, i
), memmode
);
1724 if (t
!= XEXP (x
, i
))
1727 copy
= shallow_copy_rtx (x
);
1731 else if (fmt
[i
] == 'E')
1735 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1737 rtx t
= cselib_subst_to_values (XVECEXP (x
, i
, j
), memmode
);
1739 if (t
!= XVECEXP (x
, i
, j
))
1741 if (XVEC (x
, i
) == XVEC (copy
, i
))
1744 copy
= shallow_copy_rtx (x
);
1745 XVEC (copy
, i
) = shallow_copy_rtvec (XVEC (x
, i
));
1747 XVECEXP (copy
, i
, j
) = t
;
1756 /* Look up the rtl expression X in our tables and return the value it
1757 has. If CREATE is zero, we return NULL if we don't know the value.
1758 Otherwise, we create a new one if possible, using mode MODE if X
1759 doesn't have a mode (i.e. because it's a constant). When X is part
1760 of an address, MEMMODE should be the mode of the enclosing MEM if
1761 we're tracking autoinc expressions. */
1764 cselib_lookup_1 (rtx x
, enum machine_mode mode
,
1765 int create
, enum machine_mode memmode
)
1769 unsigned int hashval
;
1771 if (GET_MODE (x
) != VOIDmode
)
1772 mode
= GET_MODE (x
);
1774 if (GET_CODE (x
) == VALUE
)
1775 return CSELIB_VAL_PTR (x
);
1780 unsigned int i
= REGNO (x
);
1783 if (l
&& l
->elt
== NULL
)
1785 for (; l
; l
= l
->next
)
1786 if (mode
== GET_MODE (l
->elt
->val_rtx
))
1788 promote_debug_loc (l
->elt
->locs
);
1795 if (i
< FIRST_PSEUDO_REGISTER
)
1797 unsigned int n
= hard_regno_nregs
[i
][mode
];
1799 if (n
> max_value_regs
)
1803 e
= new_cselib_val (next_uid
, GET_MODE (x
), x
);
1804 e
->locs
= new_elt_loc_list (e
->locs
, x
);
1805 if (REG_VALUES (i
) == 0)
1807 /* Maintain the invariant that the first entry of
1808 REG_VALUES, if present, must be the value used to set the
1809 register, or NULL. */
1810 used_regs
[n_used_regs
++] = i
;
1811 REG_VALUES (i
) = new_elt_list (REG_VALUES (i
), NULL
);
1813 REG_VALUES (i
)->next
= new_elt_list (REG_VALUES (i
)->next
, e
);
1814 slot
= cselib_find_slot (x
, e
->hash
, INSERT
, memmode
);
1820 return cselib_lookup_mem (x
, create
);
1822 hashval
= cselib_hash_rtx (x
, create
, memmode
);
1823 /* Can't even create if hashing is not possible. */
1827 slot
= cselib_find_slot (wrap_constant (mode
, x
), hashval
,
1828 create
? INSERT
: NO_INSERT
, memmode
);
1832 e
= (cselib_val
*) *slot
;
1836 e
= new_cselib_val (hashval
, mode
, x
);
1838 /* We have to fill the slot before calling cselib_subst_to_values:
1839 the hash table is inconsistent until we do so, and
1840 cselib_subst_to_values will need to do lookups. */
1842 e
->locs
= new_elt_loc_list (e
->locs
,
1843 cselib_subst_to_values (x
, memmode
));
1847 /* Wrapper for cselib_lookup, that indicates X is in INSN. */
1850 cselib_lookup_from_insn (rtx x
, enum machine_mode mode
,
1851 int create
, enum machine_mode memmode
, rtx insn
)
1855 gcc_assert (!cselib_current_insn
);
1856 cselib_current_insn
= insn
;
1858 ret
= cselib_lookup (x
, mode
, create
, memmode
);
1860 cselib_current_insn
= NULL
;
1865 /* Wrapper for cselib_lookup_1, that logs the lookup result and
1866 maintains invariants related with debug insns. */
1869 cselib_lookup (rtx x
, enum machine_mode mode
,
1870 int create
, enum machine_mode memmode
)
1872 cselib_val
*ret
= cselib_lookup_1 (x
, mode
, create
, memmode
);
1874 /* ??? Should we return NULL if we're not to create an entry, the
1875 found loc is a debug loc and cselib_current_insn is not DEBUG?
1876 If so, we should also avoid converting val to non-DEBUG; probably
1877 easiest setting cselib_current_insn to NULL before the call
1880 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1882 fputs ("cselib lookup ", dump_file
);
1883 print_inline_rtx (dump_file
, x
, 2);
1884 fprintf (dump_file
, " => %u:%u\n",
1886 ret
? ret
->hash
: 0);
1892 /* Invalidate any entries in reg_values that overlap REGNO. This is called
1893 if REGNO is changing. MODE is the mode of the assignment to REGNO, which
1894 is used to determine how many hard registers are being changed. If MODE
1895 is VOIDmode, then only REGNO is being changed; this is used when
1896 invalidating call clobbered registers across a call. */
1899 cselib_invalidate_regno (unsigned int regno
, enum machine_mode mode
)
1901 unsigned int endregno
;
1904 /* If we see pseudos after reload, something is _wrong_. */
1905 gcc_assert (!reload_completed
|| regno
< FIRST_PSEUDO_REGISTER
1906 || reg_renumber
[regno
] < 0);
1908 /* Determine the range of registers that must be invalidated. For
1909 pseudos, only REGNO is affected. For hard regs, we must take MODE
1910 into account, and we must also invalidate lower register numbers
1911 if they contain values that overlap REGNO. */
1912 if (regno
< FIRST_PSEUDO_REGISTER
)
1914 gcc_assert (mode
!= VOIDmode
);
1916 if (regno
< max_value_regs
)
1919 i
= regno
- max_value_regs
;
1921 endregno
= end_hard_regno (mode
, regno
);
1926 endregno
= regno
+ 1;
1929 for (; i
< endregno
; i
++)
1931 struct elt_list
**l
= ®_VALUES (i
);
1933 /* Go through all known values for this reg; if it overlaps the range
1934 we're invalidating, remove the value. */
1937 cselib_val
*v
= (*l
)->elt
;
1940 struct elt_loc_list
**p
;
1941 unsigned int this_last
= i
;
1943 if (i
< FIRST_PSEUDO_REGISTER
&& v
!= NULL
)
1944 this_last
= end_hard_regno (GET_MODE (v
->val_rtx
), i
) - 1;
1946 if (this_last
< regno
|| v
== NULL
1947 || (v
== cfa_base_preserved_val
1948 && i
== cfa_base_preserved_regno
))
1954 /* We have an overlap. */
1955 if (*l
== REG_VALUES (i
))
1957 /* Maintain the invariant that the first entry of
1958 REG_VALUES, if present, must be the value used to set
1959 the register, or NULL. This is also nice because
1960 then we won't push the same regno onto user_regs
1966 unchain_one_elt_list (l
);
1968 had_locs
= v
->locs
!= NULL
;
1969 setting_insn
= v
->locs
? v
->locs
->setting_insn
: NULL
;
1971 /* Now, we clear the mapping from value to reg. It must exist, so
1972 this code will crash intentionally if it doesn't. */
1973 for (p
= &v
->locs
; ; p
= &(*p
)->next
)
1977 if (REG_P (x
) && REGNO (x
) == i
)
1979 unchain_one_elt_loc_list (p
);
1984 if (had_locs
&& v
->locs
== 0 && !PRESERVED_VALUE_P (v
->val_rtx
))
1986 if (setting_insn
&& DEBUG_INSN_P (setting_insn
))
1987 n_useless_debug_values
++;
1995 /* Return 1 if X has a value that can vary even between two
1996 executions of the program. 0 means X can be compared reliably
1997 against certain constants or near-constants. */
2000 cselib_rtx_varies_p (const_rtx x ATTRIBUTE_UNUSED
, bool from_alias ATTRIBUTE_UNUSED
)
2002 /* We actually don't need to verify very hard. This is because
2003 if X has actually changed, we invalidate the memory anyway,
2004 so assume that all common memory addresses are
2009 /* Invalidate any locations in the table which are changed because of a
2010 store to MEM_RTX. If this is called because of a non-const call
2011 instruction, MEM_RTX is (mem:BLK const0_rtx). */
2014 cselib_invalidate_mem (rtx mem_rtx
)
2016 cselib_val
**vp
, *v
, *next
;
2020 mem_addr
= canon_rtx (get_addr (XEXP (mem_rtx
, 0)));
2021 mem_rtx
= canon_rtx (mem_rtx
);
2023 vp
= &first_containing_mem
;
2024 for (v
= *vp
; v
!= &dummy_val
; v
= next
)
2026 bool has_mem
= false;
2027 struct elt_loc_list
**p
= &v
->locs
;
2028 bool had_locs
= v
->locs
!= NULL
;
2029 rtx setting_insn
= v
->locs
? v
->locs
->setting_insn
: NULL
;
2035 struct elt_list
**mem_chain
;
2037 /* MEMs may occur in locations only at the top level; below
2038 that every MEM or REG is substituted by its VALUE. */
2044 if (num_mems
< PARAM_VALUE (PARAM_MAX_CSELIB_MEMORY_LOCATIONS
)
2045 && ! canon_true_dependence (mem_rtx
, GET_MODE (mem_rtx
), mem_addr
,
2046 x
, NULL_RTX
, cselib_rtx_varies_p
))
2054 /* This one overlaps. */
2055 /* We must have a mapping from this MEM's address to the
2056 value (E). Remove that, too. */
2057 addr
= cselib_lookup (XEXP (x
, 0), VOIDmode
, 0, GET_MODE (x
));
2058 mem_chain
= &addr
->addr_list
;
2061 if ((*mem_chain
)->elt
== v
)
2063 unchain_one_elt_list (mem_chain
);
2067 mem_chain
= &(*mem_chain
)->next
;
2070 unchain_one_elt_loc_list (p
);
2073 if (had_locs
&& v
->locs
== 0 && !PRESERVED_VALUE_P (v
->val_rtx
))
2075 if (setting_insn
&& DEBUG_INSN_P (setting_insn
))
2076 n_useless_debug_values
++;
2081 next
= v
->next_containing_mem
;
2085 vp
= &(*vp
)->next_containing_mem
;
2088 v
->next_containing_mem
= NULL
;
2093 /* Invalidate DEST, which is being assigned to or clobbered. */
2096 cselib_invalidate_rtx (rtx dest
)
2098 while (GET_CODE (dest
) == SUBREG
2099 || GET_CODE (dest
) == ZERO_EXTRACT
2100 || GET_CODE (dest
) == STRICT_LOW_PART
)
2101 dest
= XEXP (dest
, 0);
2104 cselib_invalidate_regno (REGNO (dest
), GET_MODE (dest
));
2105 else if (MEM_P (dest
))
2106 cselib_invalidate_mem (dest
);
2109 /* A wrapper for cselib_invalidate_rtx to be called via note_stores. */
2112 cselib_invalidate_rtx_note_stores (rtx dest
, const_rtx ignore ATTRIBUTE_UNUSED
,
2113 void *data ATTRIBUTE_UNUSED
)
2115 cselib_invalidate_rtx (dest
);
2118 /* Record the result of a SET instruction. DEST is being set; the source
2119 contains the value described by SRC_ELT. If DEST is a MEM, DEST_ADDR_ELT
2120 describes its address. */
2123 cselib_record_set (rtx dest
, cselib_val
*src_elt
, cselib_val
*dest_addr_elt
)
2125 int dreg
= REG_P (dest
) ? (int) REGNO (dest
) : -1;
2127 if (src_elt
== 0 || side_effects_p (dest
))
2132 if (dreg
< FIRST_PSEUDO_REGISTER
)
2134 unsigned int n
= hard_regno_nregs
[dreg
][GET_MODE (dest
)];
2136 if (n
> max_value_regs
)
2140 if (REG_VALUES (dreg
) == 0)
2142 used_regs
[n_used_regs
++] = dreg
;
2143 REG_VALUES (dreg
) = new_elt_list (REG_VALUES (dreg
), src_elt
);
2147 /* The register should have been invalidated. */
2148 gcc_assert (REG_VALUES (dreg
)->elt
== 0);
2149 REG_VALUES (dreg
)->elt
= src_elt
;
2152 if (src_elt
->locs
== 0 && !PRESERVED_VALUE_P (src_elt
->val_rtx
))
2154 src_elt
->locs
= new_elt_loc_list (src_elt
->locs
, dest
);
2156 else if (MEM_P (dest
) && dest_addr_elt
!= 0
2157 && cselib_record_memory
)
2159 if (src_elt
->locs
== 0 && !PRESERVED_VALUE_P (src_elt
->val_rtx
))
2161 add_mem_for_addr (dest_addr_elt
, src_elt
, dest
);
2165 /* There is no good way to determine how many elements there can be
2166 in a PARALLEL. Since it's fairly cheap, use a really large number. */
2167 #define MAX_SETS (FIRST_PSEUDO_REGISTER * 2)
2169 struct cselib_record_autoinc_data
2171 struct cselib_set
*sets
;
2175 /* Callback for for_each_inc_dec. Records in ARG the SETs implied by
2176 autoinc RTXs: SRC plus SRCOFF if non-NULL is stored in DEST. */
2179 cselib_record_autoinc_cb (rtx mem ATTRIBUTE_UNUSED
, rtx op ATTRIBUTE_UNUSED
,
2180 rtx dest
, rtx src
, rtx srcoff
, void *arg
)
2182 struct cselib_record_autoinc_data
*data
;
2183 data
= (struct cselib_record_autoinc_data
*)arg
;
2185 data
->sets
[data
->n_sets
].dest
= dest
;
2188 data
->sets
[data
->n_sets
].src
= gen_rtx_PLUS (GET_MODE (src
), src
, srcoff
);
2190 data
->sets
[data
->n_sets
].src
= src
;
2197 /* Record the effects of any sets and autoincs in INSN. */
2199 cselib_record_sets (rtx insn
)
2203 struct cselib_set sets
[MAX_SETS
];
2204 rtx body
= PATTERN (insn
);
2206 int n_sets_before_autoinc
;
2207 struct cselib_record_autoinc_data data
;
2209 body
= PATTERN (insn
);
2210 if (GET_CODE (body
) == COND_EXEC
)
2212 cond
= COND_EXEC_TEST (body
);
2213 body
= COND_EXEC_CODE (body
);
2216 /* Find all sets. */
2217 if (GET_CODE (body
) == SET
)
2219 sets
[0].src
= SET_SRC (body
);
2220 sets
[0].dest
= SET_DEST (body
);
2223 else if (GET_CODE (body
) == PARALLEL
)
2225 /* Look through the PARALLEL and record the values being
2226 set, if possible. Also handle any CLOBBERs. */
2227 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; --i
)
2229 rtx x
= XVECEXP (body
, 0, i
);
2231 if (GET_CODE (x
) == SET
)
2233 sets
[n_sets
].src
= SET_SRC (x
);
2234 sets
[n_sets
].dest
= SET_DEST (x
);
2241 && MEM_P (sets
[0].src
)
2242 && !cselib_record_memory
2243 && MEM_READONLY_P (sets
[0].src
))
2245 rtx note
= find_reg_equal_equiv_note (insn
);
2247 if (note
&& CONSTANT_P (XEXP (note
, 0)))
2248 sets
[0].src
= XEXP (note
, 0);
2252 data
.n_sets
= n_sets_before_autoinc
= n_sets
;
2253 for_each_inc_dec (&insn
, cselib_record_autoinc_cb
, &data
);
2254 n_sets
= data
.n_sets
;
2256 /* Look up the values that are read. Do this before invalidating the
2257 locations that are written. */
2258 for (i
= 0; i
< n_sets
; i
++)
2260 rtx dest
= sets
[i
].dest
;
2262 /* A STRICT_LOW_PART can be ignored; we'll record the equivalence for
2263 the low part after invalidating any knowledge about larger modes. */
2264 if (GET_CODE (sets
[i
].dest
) == STRICT_LOW_PART
)
2265 sets
[i
].dest
= dest
= XEXP (dest
, 0);
2267 /* We don't know how to record anything but REG or MEM. */
2269 || (MEM_P (dest
) && cselib_record_memory
))
2271 rtx src
= sets
[i
].src
;
2273 src
= gen_rtx_IF_THEN_ELSE (GET_MODE (dest
), cond
, src
, dest
);
2274 sets
[i
].src_elt
= cselib_lookup (src
, GET_MODE (dest
), 1, VOIDmode
);
2277 enum machine_mode address_mode
2278 = targetm
.addr_space
.address_mode (MEM_ADDR_SPACE (dest
));
2280 sets
[i
].dest_addr_elt
= cselib_lookup (XEXP (dest
, 0),
2285 sets
[i
].dest_addr_elt
= 0;
2289 if (cselib_record_sets_hook
)
2290 cselib_record_sets_hook (insn
, sets
, n_sets
);
2292 /* Invalidate all locations written by this insn. Note that the elts we
2293 looked up in the previous loop aren't affected, just some of their
2294 locations may go away. */
2295 note_stores (body
, cselib_invalidate_rtx_note_stores
, NULL
);
2297 for (i
= n_sets_before_autoinc
; i
< n_sets
; i
++)
2298 cselib_invalidate_rtx (sets
[i
].dest
);
2300 /* If this is an asm, look for duplicate sets. This can happen when the
2301 user uses the same value as an output multiple times. This is valid
2302 if the outputs are not actually used thereafter. Treat this case as
2303 if the value isn't actually set. We do this by smashing the destination
2304 to pc_rtx, so that we won't record the value later. */
2305 if (n_sets
>= 2 && asm_noperands (body
) >= 0)
2307 for (i
= 0; i
< n_sets
; i
++)
2309 rtx dest
= sets
[i
].dest
;
2310 if (REG_P (dest
) || MEM_P (dest
))
2313 for (j
= i
+ 1; j
< n_sets
; j
++)
2314 if (rtx_equal_p (dest
, sets
[j
].dest
))
2316 sets
[i
].dest
= pc_rtx
;
2317 sets
[j
].dest
= pc_rtx
;
2323 /* Now enter the equivalences in our tables. */
2324 for (i
= 0; i
< n_sets
; i
++)
2326 rtx dest
= sets
[i
].dest
;
2328 || (MEM_P (dest
) && cselib_record_memory
))
2329 cselib_record_set (dest
, sets
[i
].src_elt
, sets
[i
].dest_addr_elt
);
2333 /* Record the effects of INSN. */
2336 cselib_process_insn (rtx insn
)
2341 cselib_current_insn
= insn
;
2343 /* Forget everything at a CODE_LABEL, a volatile asm, or a setjmp. */
2346 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2347 || (NONJUMP_INSN_P (insn
)
2348 && GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
2349 && MEM_VOLATILE_P (PATTERN (insn
))))
2351 cselib_reset_table (next_uid
);
2352 cselib_current_insn
= NULL_RTX
;
2356 if (! INSN_P (insn
))
2358 cselib_current_insn
= NULL_RTX
;
2362 /* If this is a call instruction, forget anything stored in a
2363 call clobbered register, or, if this is not a const call, in
2367 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
2368 if (call_used_regs
[i
]
2369 || (REG_VALUES (i
) && REG_VALUES (i
)->elt
2370 && HARD_REGNO_CALL_PART_CLOBBERED (i
,
2371 GET_MODE (REG_VALUES (i
)->elt
->val_rtx
))))
2372 cselib_invalidate_regno (i
, reg_raw_mode
[i
]);
2374 /* Since it is not clear how cselib is going to be used, be
2375 conservative here and treat looping pure or const functions
2376 as if they were regular functions. */
2377 if (RTL_LOOPING_CONST_OR_PURE_CALL_P (insn
)
2378 || !(RTL_CONST_OR_PURE_CALL_P (insn
)))
2379 cselib_invalidate_mem (callmem
);
2382 cselib_record_sets (insn
);
2384 /* Look for any CLOBBERs in CALL_INSN_FUNCTION_USAGE, but only
2385 after we have processed the insn. */
2387 for (x
= CALL_INSN_FUNCTION_USAGE (insn
); x
; x
= XEXP (x
, 1))
2388 if (GET_CODE (XEXP (x
, 0)) == CLOBBER
)
2389 cselib_invalidate_rtx (XEXP (XEXP (x
, 0), 0));
2391 cselib_current_insn
= NULL_RTX
;
2393 if (n_useless_values
> MAX_USELESS_VALUES
2394 /* remove_useless_values is linear in the hash table size. Avoid
2395 quadratic behavior for very large hashtables with very few
2396 useless elements. */
2397 && ((unsigned int)n_useless_values
2398 > (cselib_hash_table
->n_elements
2399 - cselib_hash_table
->n_deleted
2400 - n_debug_values
) / 4))
2401 remove_useless_values ();
2404 /* Initialize cselib for one pass. The caller must also call
2405 init_alias_analysis. */
2408 cselib_init (int record_what
)
2410 elt_list_pool
= create_alloc_pool ("elt_list",
2411 sizeof (struct elt_list
), 10);
2412 elt_loc_list_pool
= create_alloc_pool ("elt_loc_list",
2413 sizeof (struct elt_loc_list
), 10);
2414 cselib_val_pool
= create_alloc_pool ("cselib_val_list",
2415 sizeof (cselib_val
), 10);
2416 value_pool
= create_alloc_pool ("value", RTX_CODE_SIZE (VALUE
), 100);
2417 cselib_record_memory
= record_what
& CSELIB_RECORD_MEMORY
;
2418 cselib_preserve_constants
= record_what
& CSELIB_PRESERVE_CONSTANTS
;
2420 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything,
2421 see canon_true_dependence. This is only created once. */
2423 callmem
= gen_rtx_MEM (BLKmode
, gen_rtx_SCRATCH (VOIDmode
));
2425 cselib_nregs
= max_reg_num ();
2427 /* We preserve reg_values to allow expensive clearing of the whole thing.
2428 Reallocate it however if it happens to be too large. */
2429 if (!reg_values
|| reg_values_size
< cselib_nregs
2430 || (reg_values_size
> 10 && reg_values_size
> cselib_nregs
* 4))
2434 /* Some space for newly emit instructions so we don't end up
2435 reallocating in between passes. */
2436 reg_values_size
= cselib_nregs
+ (63 + cselib_nregs
) / 16;
2437 reg_values
= XCNEWVEC (struct elt_list
*, reg_values_size
);
2439 used_regs
= XNEWVEC (unsigned int, cselib_nregs
);
2441 cselib_hash_table
= htab_create (31, get_value_hash
,
2442 entry_and_rtx_equal_p
, NULL
);
2446 /* Called when the current user is done with cselib. */
2449 cselib_finish (void)
2451 cselib_discard_hook
= NULL
;
2452 cselib_preserve_constants
= false;
2453 cfa_base_preserved_val
= NULL
;
2454 cfa_base_preserved_regno
= INVALID_REGNUM
;
2455 free_alloc_pool (elt_list_pool
);
2456 free_alloc_pool (elt_loc_list_pool
);
2457 free_alloc_pool (cselib_val_pool
);
2458 free_alloc_pool (value_pool
);
2459 cselib_clear_table ();
2460 htab_delete (cselib_hash_table
);
2463 cselib_hash_table
= 0;
2464 n_useless_values
= 0;
2465 n_useless_debug_values
= 0;
2470 /* Dump the cselib_val *X to FILE *info. */
2473 dump_cselib_val (void **x
, void *info
)
2475 cselib_val
*v
= (cselib_val
*)*x
;
2476 FILE *out
= (FILE *)info
;
2477 bool need_lf
= true;
2479 print_inline_rtx (out
, v
->val_rtx
, 0);
2483 struct elt_loc_list
*l
= v
->locs
;
2489 fputs (" locs:", out
);
2492 fprintf (out
, "\n from insn %i ",
2493 INSN_UID (l
->setting_insn
));
2494 print_inline_rtx (out
, l
->loc
, 4);
2496 while ((l
= l
->next
));
2501 fputs (" no locs", out
);
2507 struct elt_list
*e
= v
->addr_list
;
2513 fputs (" addr list:", out
);
2517 print_inline_rtx (out
, e
->elt
->val_rtx
, 2);
2519 while ((e
= e
->next
));
2524 fputs (" no addrs", out
);
2528 if (v
->next_containing_mem
== &dummy_val
)
2529 fputs (" last mem\n", out
);
2530 else if (v
->next_containing_mem
)
2532 fputs (" next mem ", out
);
2533 print_inline_rtx (out
, v
->next_containing_mem
->val_rtx
, 2);
2542 /* Dump to OUT everything in the CSELIB table. */
2545 dump_cselib_table (FILE *out
)
2547 fprintf (out
, "cselib hash table:\n");
2548 htab_traverse (cselib_hash_table
, dump_cselib_val
, out
);
2549 if (first_containing_mem
!= &dummy_val
)
2551 fputs ("first mem ", out
);
2552 print_inline_rtx (out
, first_containing_mem
->val_rtx
, 2);
2555 fprintf (out
, "next uid %i\n", next_uid
);
2558 #include "gt-cselib.h"