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 rtx_equal_for_cselib_1 (ENTRY_VALUE_EXP (x
), ENTRY_VALUE_EXP (y
),
811 return XEXP (x
, 0) == XEXP (y
, 0);
814 /* We have to compare any autoinc operations in the addresses
815 using this MEM's mode. */
816 return rtx_equal_for_cselib_1 (XEXP (x
, 0), XEXP (y
, 0), GET_MODE (x
));
823 fmt
= GET_RTX_FORMAT (code
);
825 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
832 if (XWINT (x
, i
) != XWINT (y
, i
))
838 if (XINT (x
, i
) != XINT (y
, i
))
844 /* Two vectors must have the same length. */
845 if (XVECLEN (x
, i
) != XVECLEN (y
, i
))
848 /* And the corresponding elements must match. */
849 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
850 if (! rtx_equal_for_cselib_1 (XVECEXP (x
, i
, j
),
851 XVECEXP (y
, i
, j
), memmode
))
857 && targetm
.commutative_p (x
, UNKNOWN
)
858 && rtx_equal_for_cselib_1 (XEXP (x
, 1), XEXP (y
, 0), memmode
)
859 && rtx_equal_for_cselib_1 (XEXP (x
, 0), XEXP (y
, 1), memmode
))
861 if (! rtx_equal_for_cselib_1 (XEXP (x
, i
), XEXP (y
, i
), memmode
))
867 if (strcmp (XSTR (x
, i
), XSTR (y
, i
)))
872 /* These are just backpointers, so they don't matter. */
879 /* It is believed that rtx's at this level will never
880 contain anything but integers and other rtx's,
881 except for within LABEL_REFs and SYMBOL_REFs. */
889 /* We need to pass down the mode of constants through the hash table
890 functions. For that purpose, wrap them in a CONST of the appropriate
893 wrap_constant (enum machine_mode mode
, rtx x
)
895 if (!CONST_INT_P (x
) && GET_CODE (x
) != CONST_FIXED
896 && (GET_CODE (x
) != CONST_DOUBLE
|| GET_MODE (x
) != VOIDmode
))
898 gcc_assert (mode
!= VOIDmode
);
899 return gen_rtx_CONST (mode
, x
);
902 /* Hash an rtx. Return 0 if we couldn't hash the rtx.
903 For registers and memory locations, we look up their cselib_val structure
904 and return its VALUE element.
905 Possible reasons for return 0 are: the object is volatile, or we couldn't
906 find a register or memory location in the table and CREATE is zero. If
907 CREATE is nonzero, table elts are created for regs and mem.
908 N.B. this hash function returns the same hash value for RTXes that
909 differ only in the order of operands, thus it is suitable for comparisons
910 that take commutativity into account.
911 If we wanted to also support associative rules, we'd have to use a different
912 strategy to avoid returning spurious 0, e.g. return ~(~0U >> 1) .
913 MEMMODE indicates the mode of an enclosing MEM, and it's only
914 used to compute autoinc values.
915 We used to have a MODE argument for hashing for CONST_INTs, but that
916 didn't make sense, since it caused spurious hash differences between
917 (set (reg:SI 1) (const_int))
918 (plus:SI (reg:SI 2) (reg:SI 1))
920 (plus:SI (reg:SI 2) (const_int))
921 If the mode is important in any context, it must be checked specifically
922 in a comparison anyway, since relying on hash differences is unsafe. */
925 cselib_hash_rtx (rtx x
, int create
, enum machine_mode memmode
)
931 unsigned int hash
= 0;
934 hash
+= (unsigned) code
+ (unsigned) GET_MODE (x
);
940 e
= cselib_lookup (x
, GET_MODE (x
), create
, memmode
);
947 hash
+= ((unsigned) DEBUG_EXPR
<< 7)
948 + DEBUG_TEMP_UID (DEBUG_EXPR_TREE_DECL (x
));
949 return hash
? hash
: (unsigned int) DEBUG_EXPR
;
951 case DEBUG_IMPLICIT_PTR
:
952 hash
+= ((unsigned) DEBUG_IMPLICIT_PTR
<< 7)
953 + DECL_UID (DEBUG_IMPLICIT_PTR_DECL (x
));
954 return hash
? hash
: (unsigned int) DEBUG_IMPLICIT_PTR
;
957 hash
+= cselib_hash_rtx (ENTRY_VALUE_EXP (x
), create
, memmode
);
958 return hash
? hash
: (unsigned int) ENTRY_VALUE
;
961 hash
+= ((unsigned) CONST_INT
<< 7) + INTVAL (x
);
962 return hash
? hash
: (unsigned int) CONST_INT
;
965 /* This is like the general case, except that it only counts
966 the integers representing the constant. */
967 hash
+= (unsigned) code
+ (unsigned) GET_MODE (x
);
968 if (GET_MODE (x
) != VOIDmode
)
969 hash
+= real_hash (CONST_DOUBLE_REAL_VALUE (x
));
971 hash
+= ((unsigned) CONST_DOUBLE_LOW (x
)
972 + (unsigned) CONST_DOUBLE_HIGH (x
));
973 return hash
? hash
: (unsigned int) CONST_DOUBLE
;
976 hash
+= (unsigned int) code
+ (unsigned int) GET_MODE (x
);
977 hash
+= fixed_hash (CONST_FIXED_VALUE (x
));
978 return hash
? hash
: (unsigned int) CONST_FIXED
;
985 units
= CONST_VECTOR_NUNITS (x
);
987 for (i
= 0; i
< units
; ++i
)
989 elt
= CONST_VECTOR_ELT (x
, i
);
990 hash
+= cselib_hash_rtx (elt
, 0, memmode
);
996 /* Assume there is only one rtx object for any given label. */
998 /* We don't hash on the address of the CODE_LABEL to avoid bootstrap
999 differences and differences between each stage's debugging dumps. */
1000 hash
+= (((unsigned int) LABEL_REF
<< 7)
1001 + CODE_LABEL_NUMBER (XEXP (x
, 0)));
1002 return hash
? hash
: (unsigned int) LABEL_REF
;
1006 /* Don't hash on the symbol's address to avoid bootstrap differences.
1007 Different hash values may cause expressions to be recorded in
1008 different orders and thus different registers to be used in the
1009 final assembler. This also avoids differences in the dump files
1010 between various stages. */
1012 const unsigned char *p
= (const unsigned char *) XSTR (x
, 0);
1015 h
+= (h
<< 7) + *p
++; /* ??? revisit */
1017 hash
+= ((unsigned int) SYMBOL_REF
<< 7) + h
;
1018 return hash
? hash
: (unsigned int) SYMBOL_REF
;
1023 /* We can't compute these without knowing the MEM mode. */
1024 gcc_assert (memmode
!= VOIDmode
);
1025 i
= GET_MODE_SIZE (memmode
);
1026 if (code
== PRE_DEC
)
1028 /* Adjust the hash so that (mem:MEMMODE (pre_* (reg))) hashes
1029 like (mem:MEMMODE (plus (reg) (const_int I))). */
1030 hash
+= (unsigned) PLUS
- (unsigned)code
1031 + cselib_hash_rtx (XEXP (x
, 0), create
, memmode
)
1032 + cselib_hash_rtx (GEN_INT (i
), create
, memmode
);
1033 return hash
? hash
: 1 + (unsigned) PLUS
;
1036 gcc_assert (memmode
!= VOIDmode
);
1037 return cselib_hash_rtx (XEXP (x
, 1), create
, memmode
);
1042 gcc_assert (memmode
!= VOIDmode
);
1043 return cselib_hash_rtx (XEXP (x
, 0), create
, memmode
);
1048 case UNSPEC_VOLATILE
:
1052 if (MEM_VOLATILE_P (x
))
1061 i
= GET_RTX_LENGTH (code
) - 1;
1062 fmt
= GET_RTX_FORMAT (code
);
1069 rtx tem
= XEXP (x
, i
);
1070 unsigned int tem_hash
= cselib_hash_rtx (tem
, create
, memmode
);
1079 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1081 unsigned int tem_hash
1082 = cselib_hash_rtx (XVECEXP (x
, i
, j
), create
, memmode
);
1093 const unsigned char *p
= (const unsigned char *) XSTR (x
, i
);
1102 hash
+= XINT (x
, i
);
1115 return hash
? hash
: 1 + (unsigned int) GET_CODE (x
);
1118 /* Create a new value structure for VALUE and initialize it. The mode of the
1121 static inline cselib_val
*
1122 new_cselib_val (unsigned int hash
, enum machine_mode mode
, rtx x
)
1124 cselib_val
*e
= (cselib_val
*) pool_alloc (cselib_val_pool
);
1127 gcc_assert (next_uid
);
1130 e
->uid
= next_uid
++;
1131 /* We use an alloc pool to allocate this RTL construct because it
1132 accounts for about 8% of the overall memory usage. We know
1133 precisely when we can have VALUE RTXen (when cselib is active)
1134 so we don't need to put them in garbage collected memory.
1135 ??? Why should a VALUE be an RTX in the first place? */
1136 e
->val_rtx
= (rtx
) pool_alloc (value_pool
);
1137 memset (e
->val_rtx
, 0, RTX_HDR_SIZE
);
1138 PUT_CODE (e
->val_rtx
, VALUE
);
1139 PUT_MODE (e
->val_rtx
, mode
);
1140 CSELIB_VAL_PTR (e
->val_rtx
) = e
;
1143 e
->next_containing_mem
= 0;
1145 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1147 fprintf (dump_file
, "cselib value %u:%u ", e
->uid
, hash
);
1148 if (flag_dump_noaddr
|| flag_dump_unnumbered
)
1149 fputs ("# ", dump_file
);
1151 fprintf (dump_file
, "%p ", (void*)e
);
1152 print_rtl_single (dump_file
, x
);
1153 fputc ('\n', dump_file
);
1159 /* ADDR_ELT is a value that is used as address. MEM_ELT is the value that
1160 contains the data at this address. X is a MEM that represents the
1161 value. Update the two value structures to represent this situation. */
1164 add_mem_for_addr (cselib_val
*addr_elt
, cselib_val
*mem_elt
, rtx x
)
1166 struct elt_loc_list
*l
;
1168 /* Avoid duplicates. */
1169 for (l
= mem_elt
->locs
; l
; l
= l
->next
)
1171 && CSELIB_VAL_PTR (XEXP (l
->loc
, 0)) == addr_elt
)
1173 promote_debug_loc (l
);
1177 addr_elt
->addr_list
= new_elt_list (addr_elt
->addr_list
, mem_elt
);
1179 = new_elt_loc_list (mem_elt
->locs
,
1180 replace_equiv_address_nv (x
, addr_elt
->val_rtx
));
1181 if (mem_elt
->next_containing_mem
== NULL
)
1183 mem_elt
->next_containing_mem
= first_containing_mem
;
1184 first_containing_mem
= mem_elt
;
1188 /* Subroutine of cselib_lookup. Return a value for X, which is a MEM rtx.
1189 If CREATE, make a new one if we haven't seen it before. */
1192 cselib_lookup_mem (rtx x
, int create
)
1194 enum machine_mode mode
= GET_MODE (x
);
1195 enum machine_mode addr_mode
;
1198 cselib_val
*mem_elt
;
1201 if (MEM_VOLATILE_P (x
) || mode
== BLKmode
1202 || !cselib_record_memory
1203 || (FLOAT_MODE_P (mode
) && flag_float_store
))
1206 addr_mode
= GET_MODE (XEXP (x
, 0));
1207 if (addr_mode
== VOIDmode
)
1210 /* Look up the value for the address. */
1211 addr
= cselib_lookup (XEXP (x
, 0), addr_mode
, create
, mode
);
1215 /* Find a value that describes a value of our mode at that address. */
1216 for (l
= addr
->addr_list
; l
; l
= l
->next
)
1217 if (GET_MODE (l
->elt
->val_rtx
) == mode
)
1219 promote_debug_loc (l
->elt
->locs
);
1226 mem_elt
= new_cselib_val (next_uid
, mode
, x
);
1227 add_mem_for_addr (addr
, mem_elt
, x
);
1228 slot
= cselib_find_slot (wrap_constant (mode
, x
), mem_elt
->hash
,
1234 /* Search thru the possible substitutions in P. We prefer a non reg
1235 substitution because this allows us to expand the tree further. If
1236 we find, just a reg, take the lowest regno. There may be several
1237 non-reg results, we just take the first one because they will all
1238 expand to the same place. */
1241 expand_loc (struct elt_loc_list
*p
, struct expand_value_data
*evd
,
1244 rtx reg_result
= NULL
;
1245 unsigned int regno
= UINT_MAX
;
1246 struct elt_loc_list
*p_in
= p
;
1248 for (; p
; p
= p
-> next
)
1250 /* Avoid infinite recursion trying to expand a reg into a
1252 if ((REG_P (p
->loc
))
1253 && (REGNO (p
->loc
) < regno
)
1254 && !bitmap_bit_p (evd
->regs_active
, REGNO (p
->loc
)))
1256 reg_result
= p
->loc
;
1257 regno
= REGNO (p
->loc
);
1259 /* Avoid infinite recursion and do not try to expand the
1261 else if (GET_CODE (p
->loc
) == VALUE
1262 && CSELIB_VAL_PTR (p
->loc
)->locs
== p_in
)
1264 else if (!REG_P (p
->loc
))
1267 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1269 print_inline_rtx (dump_file
, p
->loc
, 0);
1270 fprintf (dump_file
, "\n");
1272 if (GET_CODE (p
->loc
) == LO_SUM
1273 && GET_CODE (XEXP (p
->loc
, 1)) == SYMBOL_REF
1275 && (note
= find_reg_note (p
->setting_insn
, REG_EQUAL
, NULL_RTX
))
1276 && XEXP (note
, 0) == XEXP (p
->loc
, 1))
1277 return XEXP (p
->loc
, 1);
1278 result
= cselib_expand_value_rtx_1 (p
->loc
, evd
, max_depth
- 1);
1285 if (regno
!= UINT_MAX
)
1288 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1289 fprintf (dump_file
, "r%d\n", regno
);
1291 result
= cselib_expand_value_rtx_1 (reg_result
, evd
, max_depth
- 1);
1296 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1300 print_inline_rtx (dump_file
, reg_result
, 0);
1301 fprintf (dump_file
, "\n");
1304 fprintf (dump_file
, "NULL\n");
1310 /* Forward substitute and expand an expression out to its roots.
1311 This is the opposite of common subexpression. Because local value
1312 numbering is such a weak optimization, the expanded expression is
1313 pretty much unique (not from a pointer equals point of view but
1314 from a tree shape point of view.
1316 This function returns NULL if the expansion fails. The expansion
1317 will fail if there is no value number for one of the operands or if
1318 one of the operands has been overwritten between the current insn
1319 and the beginning of the basic block. For instance x has no
1325 REGS_ACTIVE is a scratch bitmap that should be clear when passing in.
1326 It is clear on return. */
1329 cselib_expand_value_rtx (rtx orig
, bitmap regs_active
, int max_depth
)
1331 struct expand_value_data evd
;
1333 evd
.regs_active
= regs_active
;
1334 evd
.callback
= NULL
;
1335 evd
.callback_arg
= NULL
;
1338 return cselib_expand_value_rtx_1 (orig
, &evd
, max_depth
);
1341 /* Same as cselib_expand_value_rtx, but using a callback to try to
1342 resolve some expressions. The CB function should return ORIG if it
1343 can't or does not want to deal with a certain RTX. Any other
1344 return value, including NULL, will be used as the expansion for
1345 VALUE, without any further changes. */
1348 cselib_expand_value_rtx_cb (rtx orig
, bitmap regs_active
, int max_depth
,
1349 cselib_expand_callback cb
, void *data
)
1351 struct expand_value_data evd
;
1353 evd
.regs_active
= regs_active
;
1355 evd
.callback_arg
= data
;
1358 return cselib_expand_value_rtx_1 (orig
, &evd
, max_depth
);
1361 /* Similar to cselib_expand_value_rtx_cb, but no rtxs are actually copied
1362 or simplified. Useful to find out whether cselib_expand_value_rtx_cb
1363 would return NULL or non-NULL, without allocating new rtx. */
1366 cselib_dummy_expand_value_rtx_cb (rtx orig
, bitmap regs_active
, int max_depth
,
1367 cselib_expand_callback cb
, void *data
)
1369 struct expand_value_data evd
;
1371 evd
.regs_active
= regs_active
;
1373 evd
.callback_arg
= data
;
1376 return cselib_expand_value_rtx_1 (orig
, &evd
, max_depth
) != NULL
;
1379 /* Internal implementation of cselib_expand_value_rtx and
1380 cselib_expand_value_rtx_cb. */
1383 cselib_expand_value_rtx_1 (rtx orig
, struct expand_value_data
*evd
,
1389 const char *format_ptr
;
1390 enum machine_mode mode
;
1392 code
= GET_CODE (orig
);
1394 /* For the context of dse, if we end up expand into a huge tree, we
1395 will not have a useful address, so we might as well just give up
1404 struct elt_list
*l
= REG_VALUES (REGNO (orig
));
1406 if (l
&& l
->elt
== NULL
)
1408 for (; l
; l
= l
->next
)
1409 if (GET_MODE (l
->elt
->val_rtx
) == GET_MODE (orig
))
1412 int regno
= REGNO (orig
);
1414 /* The only thing that we are not willing to do (this
1415 is requirement of dse and if others potential uses
1416 need this function we should add a parm to control
1417 it) is that we will not substitute the
1418 STACK_POINTER_REGNUM, FRAME_POINTER or the
1421 These expansions confuses the code that notices that
1422 stores into the frame go dead at the end of the
1423 function and that the frame is not effected by calls
1424 to subroutines. If you allow the
1425 STACK_POINTER_REGNUM substitution, then dse will
1426 think that parameter pushing also goes dead which is
1427 wrong. If you allow the FRAME_POINTER or the
1428 HARD_FRAME_POINTER then you lose the opportunity to
1429 make the frame assumptions. */
1430 if (regno
== STACK_POINTER_REGNUM
1431 || regno
== FRAME_POINTER_REGNUM
1432 || regno
== HARD_FRAME_POINTER_REGNUM
)
1435 bitmap_set_bit (evd
->regs_active
, regno
);
1437 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1438 fprintf (dump_file
, "expanding: r%d into: ", regno
);
1440 result
= expand_loc (l
->elt
->locs
, evd
, max_depth
);
1441 bitmap_clear_bit (evd
->regs_active
, regno
);
1458 /* SCRATCH must be shared because they represent distinct values. */
1461 if (REG_P (XEXP (orig
, 0)) && HARD_REGISTER_NUM_P (REGNO (XEXP (orig
, 0))))
1466 if (shared_const_p (orig
))
1476 subreg
= evd
->callback (orig
, evd
->regs_active
, max_depth
,
1482 subreg
= cselib_expand_value_rtx_1 (SUBREG_REG (orig
), evd
,
1486 scopy
= simplify_gen_subreg (GET_MODE (orig
), subreg
,
1487 GET_MODE (SUBREG_REG (orig
)),
1488 SUBREG_BYTE (orig
));
1490 || (GET_CODE (scopy
) == SUBREG
1491 && !REG_P (SUBREG_REG (scopy
))
1492 && !MEM_P (SUBREG_REG (scopy
))))
1502 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1504 fputs ("\nexpanding ", dump_file
);
1505 print_rtl_single (dump_file
, orig
);
1506 fputs (" into...", dump_file
);
1511 result
= evd
->callback (orig
, evd
->regs_active
, max_depth
,
1518 result
= expand_loc (CSELIB_VAL_PTR (orig
)->locs
, evd
, max_depth
);
1524 return evd
->callback (orig
, evd
->regs_active
, max_depth
,
1532 /* Copy the various flags, fields, and other information. We assume
1533 that all fields need copying, and then clear the fields that should
1534 not be copied. That is the sensible default behavior, and forces
1535 us to explicitly document why we are *not* copying a flag. */
1539 copy
= shallow_copy_rtx (orig
);
1541 format_ptr
= GET_RTX_FORMAT (code
);
1543 for (i
= 0; i
< GET_RTX_LENGTH (code
); i
++)
1544 switch (*format_ptr
++)
1547 if (XEXP (orig
, i
) != NULL
)
1549 rtx result
= cselib_expand_value_rtx_1 (XEXP (orig
, i
), evd
,
1554 XEXP (copy
, i
) = result
;
1560 if (XVEC (orig
, i
) != NULL
)
1563 XVEC (copy
, i
) = rtvec_alloc (XVECLEN (orig
, i
));
1564 for (j
= 0; j
< XVECLEN (orig
, i
); j
++)
1566 rtx result
= cselib_expand_value_rtx_1 (XVECEXP (orig
, i
, j
),
1567 evd
, max_depth
- 1);
1571 XVECEXP (copy
, i
, j
) = result
;
1585 /* These are left unchanged. */
1595 mode
= GET_MODE (copy
);
1596 /* If an operand has been simplified into CONST_INT, which doesn't
1597 have a mode and the mode isn't derivable from whole rtx's mode,
1598 try simplify_*_operation first with mode from original's operand
1599 and as a fallback wrap CONST_INT into gen_rtx_CONST. */
1601 switch (GET_RTX_CLASS (code
))
1604 if (CONST_INT_P (XEXP (copy
, 0))
1605 && GET_MODE (XEXP (orig
, 0)) != VOIDmode
)
1607 scopy
= simplify_unary_operation (code
, mode
, XEXP (copy
, 0),
1608 GET_MODE (XEXP (orig
, 0)));
1613 case RTX_COMM_ARITH
:
1615 /* These expressions can derive operand modes from the whole rtx's mode. */
1618 case RTX_BITFIELD_OPS
:
1619 if (CONST_INT_P (XEXP (copy
, 0))
1620 && GET_MODE (XEXP (orig
, 0)) != VOIDmode
)
1622 scopy
= simplify_ternary_operation (code
, mode
,
1623 GET_MODE (XEXP (orig
, 0)),
1624 XEXP (copy
, 0), XEXP (copy
, 1),
1631 case RTX_COMM_COMPARE
:
1632 if (CONST_INT_P (XEXP (copy
, 0))
1633 && GET_MODE (XEXP (copy
, 1)) == VOIDmode
1634 && (GET_MODE (XEXP (orig
, 0)) != VOIDmode
1635 || GET_MODE (XEXP (orig
, 1)) != VOIDmode
))
1637 scopy
= simplify_relational_operation (code
, mode
,
1638 (GET_MODE (XEXP (orig
, 0))
1640 ? GET_MODE (XEXP (orig
, 0))
1641 : GET_MODE (XEXP (orig
, 1)),
1651 scopy
= simplify_rtx (copy
);
1657 /* Walk rtx X and replace all occurrences of REG and MEM subexpressions
1658 with VALUE expressions. This way, it becomes independent of changes
1659 to registers and memory.
1660 X isn't actually modified; if modifications are needed, new rtl is
1661 allocated. However, the return value can share rtl with X.
1662 If X is within a MEM, MEMMODE must be the mode of the MEM. */
1665 cselib_subst_to_values (rtx x
, enum machine_mode memmode
)
1667 enum rtx_code code
= GET_CODE (x
);
1668 const char *fmt
= GET_RTX_FORMAT (code
);
1677 l
= REG_VALUES (REGNO (x
));
1678 if (l
&& l
->elt
== NULL
)
1680 for (; l
; l
= l
->next
)
1681 if (GET_MODE (l
->elt
->val_rtx
) == GET_MODE (x
))
1682 return l
->elt
->val_rtx
;
1687 e
= cselib_lookup_mem (x
, 0);
1688 /* This used to happen for autoincrements, but we deal with them
1689 properly now. Remove the if stmt for the next release. */
1692 /* Assign a value that doesn't match any other. */
1693 e
= new_cselib_val (next_uid
, GET_MODE (x
), x
);
1705 gcc_assert (memmode
!= VOIDmode
);
1706 i
= GET_MODE_SIZE (memmode
);
1707 if (code
== PRE_DEC
)
1709 return cselib_subst_to_values (plus_constant (XEXP (x
, 0), i
),
1713 gcc_assert (memmode
!= VOIDmode
);
1714 return cselib_subst_to_values (XEXP (x
, 1), memmode
);
1719 gcc_assert (memmode
!= VOIDmode
);
1720 return cselib_subst_to_values (XEXP (x
, 0), memmode
);
1726 for (i
= GET_RTX_LENGTH (code
) - 1; i
>= 0; i
--)
1730 rtx t
= cselib_subst_to_values (XEXP (x
, i
), memmode
);
1732 if (t
!= XEXP (x
, i
))
1735 copy
= shallow_copy_rtx (x
);
1739 else if (fmt
[i
] == 'E')
1743 for (j
= 0; j
< XVECLEN (x
, i
); j
++)
1745 rtx t
= cselib_subst_to_values (XVECEXP (x
, i
, j
), memmode
);
1747 if (t
!= XVECEXP (x
, i
, j
))
1749 if (XVEC (x
, i
) == XVEC (copy
, i
))
1752 copy
= shallow_copy_rtx (x
);
1753 XVEC (copy
, i
) = shallow_copy_rtvec (XVEC (x
, i
));
1755 XVECEXP (copy
, i
, j
) = t
;
1764 /* Look up the rtl expression X in our tables and return the value it
1765 has. If CREATE is zero, we return NULL if we don't know the value.
1766 Otherwise, we create a new one if possible, using mode MODE if X
1767 doesn't have a mode (i.e. because it's a constant). When X is part
1768 of an address, MEMMODE should be the mode of the enclosing MEM if
1769 we're tracking autoinc expressions. */
1772 cselib_lookup_1 (rtx x
, enum machine_mode mode
,
1773 int create
, enum machine_mode memmode
)
1777 unsigned int hashval
;
1779 if (GET_MODE (x
) != VOIDmode
)
1780 mode
= GET_MODE (x
);
1782 if (GET_CODE (x
) == VALUE
)
1783 return CSELIB_VAL_PTR (x
);
1788 unsigned int i
= REGNO (x
);
1791 if (l
&& l
->elt
== NULL
)
1793 for (; l
; l
= l
->next
)
1794 if (mode
== GET_MODE (l
->elt
->val_rtx
))
1796 promote_debug_loc (l
->elt
->locs
);
1803 if (i
< FIRST_PSEUDO_REGISTER
)
1805 unsigned int n
= hard_regno_nregs
[i
][mode
];
1807 if (n
> max_value_regs
)
1811 e
= new_cselib_val (next_uid
, GET_MODE (x
), x
);
1812 e
->locs
= new_elt_loc_list (e
->locs
, x
);
1813 if (REG_VALUES (i
) == 0)
1815 /* Maintain the invariant that the first entry of
1816 REG_VALUES, if present, must be the value used to set the
1817 register, or NULL. */
1818 used_regs
[n_used_regs
++] = i
;
1819 REG_VALUES (i
) = new_elt_list (REG_VALUES (i
), NULL
);
1821 REG_VALUES (i
)->next
= new_elt_list (REG_VALUES (i
)->next
, e
);
1822 slot
= cselib_find_slot (x
, e
->hash
, INSERT
, memmode
);
1828 return cselib_lookup_mem (x
, create
);
1830 hashval
= cselib_hash_rtx (x
, create
, memmode
);
1831 /* Can't even create if hashing is not possible. */
1835 slot
= cselib_find_slot (wrap_constant (mode
, x
), hashval
,
1836 create
? INSERT
: NO_INSERT
, memmode
);
1840 e
= (cselib_val
*) *slot
;
1844 e
= new_cselib_val (hashval
, mode
, x
);
1846 /* We have to fill the slot before calling cselib_subst_to_values:
1847 the hash table is inconsistent until we do so, and
1848 cselib_subst_to_values will need to do lookups. */
1850 e
->locs
= new_elt_loc_list (e
->locs
,
1851 cselib_subst_to_values (x
, memmode
));
1855 /* Wrapper for cselib_lookup, that indicates X is in INSN. */
1858 cselib_lookup_from_insn (rtx x
, enum machine_mode mode
,
1859 int create
, enum machine_mode memmode
, rtx insn
)
1863 gcc_assert (!cselib_current_insn
);
1864 cselib_current_insn
= insn
;
1866 ret
= cselib_lookup (x
, mode
, create
, memmode
);
1868 cselib_current_insn
= NULL
;
1873 /* Wrapper for cselib_lookup_1, that logs the lookup result and
1874 maintains invariants related with debug insns. */
1877 cselib_lookup (rtx x
, enum machine_mode mode
,
1878 int create
, enum machine_mode memmode
)
1880 cselib_val
*ret
= cselib_lookup_1 (x
, mode
, create
, memmode
);
1882 /* ??? Should we return NULL if we're not to create an entry, the
1883 found loc is a debug loc and cselib_current_insn is not DEBUG?
1884 If so, we should also avoid converting val to non-DEBUG; probably
1885 easiest setting cselib_current_insn to NULL before the call
1888 if (dump_file
&& (dump_flags
& TDF_CSELIB
))
1890 fputs ("cselib lookup ", dump_file
);
1891 print_inline_rtx (dump_file
, x
, 2);
1892 fprintf (dump_file
, " => %u:%u\n",
1894 ret
? ret
->hash
: 0);
1900 /* Invalidate any entries in reg_values that overlap REGNO. This is called
1901 if REGNO is changing. MODE is the mode of the assignment to REGNO, which
1902 is used to determine how many hard registers are being changed. If MODE
1903 is VOIDmode, then only REGNO is being changed; this is used when
1904 invalidating call clobbered registers across a call. */
1907 cselib_invalidate_regno (unsigned int regno
, enum machine_mode mode
)
1909 unsigned int endregno
;
1912 /* If we see pseudos after reload, something is _wrong_. */
1913 gcc_assert (!reload_completed
|| regno
< FIRST_PSEUDO_REGISTER
1914 || reg_renumber
[regno
] < 0);
1916 /* Determine the range of registers that must be invalidated. For
1917 pseudos, only REGNO is affected. For hard regs, we must take MODE
1918 into account, and we must also invalidate lower register numbers
1919 if they contain values that overlap REGNO. */
1920 if (regno
< FIRST_PSEUDO_REGISTER
)
1922 gcc_assert (mode
!= VOIDmode
);
1924 if (regno
< max_value_regs
)
1927 i
= regno
- max_value_regs
;
1929 endregno
= end_hard_regno (mode
, regno
);
1934 endregno
= regno
+ 1;
1937 for (; i
< endregno
; i
++)
1939 struct elt_list
**l
= ®_VALUES (i
);
1941 /* Go through all known values for this reg; if it overlaps the range
1942 we're invalidating, remove the value. */
1945 cselib_val
*v
= (*l
)->elt
;
1948 struct elt_loc_list
**p
;
1949 unsigned int this_last
= i
;
1951 if (i
< FIRST_PSEUDO_REGISTER
&& v
!= NULL
)
1952 this_last
= end_hard_regno (GET_MODE (v
->val_rtx
), i
) - 1;
1954 if (this_last
< regno
|| v
== NULL
1955 || (v
== cfa_base_preserved_val
1956 && i
== cfa_base_preserved_regno
))
1962 /* We have an overlap. */
1963 if (*l
== REG_VALUES (i
))
1965 /* Maintain the invariant that the first entry of
1966 REG_VALUES, if present, must be the value used to set
1967 the register, or NULL. This is also nice because
1968 then we won't push the same regno onto user_regs
1974 unchain_one_elt_list (l
);
1976 had_locs
= v
->locs
!= NULL
;
1977 setting_insn
= v
->locs
? v
->locs
->setting_insn
: NULL
;
1979 /* Now, we clear the mapping from value to reg. It must exist, so
1980 this code will crash intentionally if it doesn't. */
1981 for (p
= &v
->locs
; ; p
= &(*p
)->next
)
1985 if (REG_P (x
) && REGNO (x
) == i
)
1987 unchain_one_elt_loc_list (p
);
1992 if (had_locs
&& v
->locs
== 0 && !PRESERVED_VALUE_P (v
->val_rtx
))
1994 if (setting_insn
&& DEBUG_INSN_P (setting_insn
))
1995 n_useless_debug_values
++;
2003 /* Return 1 if X has a value that can vary even between two
2004 executions of the program. 0 means X can be compared reliably
2005 against certain constants or near-constants. */
2008 cselib_rtx_varies_p (const_rtx x ATTRIBUTE_UNUSED
, bool from_alias ATTRIBUTE_UNUSED
)
2010 /* We actually don't need to verify very hard. This is because
2011 if X has actually changed, we invalidate the memory anyway,
2012 so assume that all common memory addresses are
2017 /* Invalidate any locations in the table which are changed because of a
2018 store to MEM_RTX. If this is called because of a non-const call
2019 instruction, MEM_RTX is (mem:BLK const0_rtx). */
2022 cselib_invalidate_mem (rtx mem_rtx
)
2024 cselib_val
**vp
, *v
, *next
;
2028 mem_addr
= canon_rtx (get_addr (XEXP (mem_rtx
, 0)));
2029 mem_rtx
= canon_rtx (mem_rtx
);
2031 vp
= &first_containing_mem
;
2032 for (v
= *vp
; v
!= &dummy_val
; v
= next
)
2034 bool has_mem
= false;
2035 struct elt_loc_list
**p
= &v
->locs
;
2036 bool had_locs
= v
->locs
!= NULL
;
2037 rtx setting_insn
= v
->locs
? v
->locs
->setting_insn
: NULL
;
2043 struct elt_list
**mem_chain
;
2045 /* MEMs may occur in locations only at the top level; below
2046 that every MEM or REG is substituted by its VALUE. */
2052 if (num_mems
< PARAM_VALUE (PARAM_MAX_CSELIB_MEMORY_LOCATIONS
)
2053 && ! canon_true_dependence (mem_rtx
, GET_MODE (mem_rtx
), mem_addr
,
2054 x
, NULL_RTX
, cselib_rtx_varies_p
))
2062 /* This one overlaps. */
2063 /* We must have a mapping from this MEM's address to the
2064 value (E). Remove that, too. */
2065 addr
= cselib_lookup (XEXP (x
, 0), VOIDmode
, 0, GET_MODE (x
));
2066 mem_chain
= &addr
->addr_list
;
2069 if ((*mem_chain
)->elt
== v
)
2071 unchain_one_elt_list (mem_chain
);
2075 mem_chain
= &(*mem_chain
)->next
;
2078 unchain_one_elt_loc_list (p
);
2081 if (had_locs
&& v
->locs
== 0 && !PRESERVED_VALUE_P (v
->val_rtx
))
2083 if (setting_insn
&& DEBUG_INSN_P (setting_insn
))
2084 n_useless_debug_values
++;
2089 next
= v
->next_containing_mem
;
2093 vp
= &(*vp
)->next_containing_mem
;
2096 v
->next_containing_mem
= NULL
;
2101 /* Invalidate DEST, which is being assigned to or clobbered. */
2104 cselib_invalidate_rtx (rtx dest
)
2106 while (GET_CODE (dest
) == SUBREG
2107 || GET_CODE (dest
) == ZERO_EXTRACT
2108 || GET_CODE (dest
) == STRICT_LOW_PART
)
2109 dest
= XEXP (dest
, 0);
2112 cselib_invalidate_regno (REGNO (dest
), GET_MODE (dest
));
2113 else if (MEM_P (dest
))
2114 cselib_invalidate_mem (dest
);
2117 /* A wrapper for cselib_invalidate_rtx to be called via note_stores. */
2120 cselib_invalidate_rtx_note_stores (rtx dest
, const_rtx ignore ATTRIBUTE_UNUSED
,
2121 void *data ATTRIBUTE_UNUSED
)
2123 cselib_invalidate_rtx (dest
);
2126 /* Record the result of a SET instruction. DEST is being set; the source
2127 contains the value described by SRC_ELT. If DEST is a MEM, DEST_ADDR_ELT
2128 describes its address. */
2131 cselib_record_set (rtx dest
, cselib_val
*src_elt
, cselib_val
*dest_addr_elt
)
2133 int dreg
= REG_P (dest
) ? (int) REGNO (dest
) : -1;
2135 if (src_elt
== 0 || side_effects_p (dest
))
2140 if (dreg
< FIRST_PSEUDO_REGISTER
)
2142 unsigned int n
= hard_regno_nregs
[dreg
][GET_MODE (dest
)];
2144 if (n
> max_value_regs
)
2148 if (REG_VALUES (dreg
) == 0)
2150 used_regs
[n_used_regs
++] = dreg
;
2151 REG_VALUES (dreg
) = new_elt_list (REG_VALUES (dreg
), src_elt
);
2155 /* The register should have been invalidated. */
2156 gcc_assert (REG_VALUES (dreg
)->elt
== 0);
2157 REG_VALUES (dreg
)->elt
= src_elt
;
2160 if (src_elt
->locs
== 0 && !PRESERVED_VALUE_P (src_elt
->val_rtx
))
2162 src_elt
->locs
= new_elt_loc_list (src_elt
->locs
, dest
);
2164 else if (MEM_P (dest
) && dest_addr_elt
!= 0
2165 && cselib_record_memory
)
2167 if (src_elt
->locs
== 0 && !PRESERVED_VALUE_P (src_elt
->val_rtx
))
2169 add_mem_for_addr (dest_addr_elt
, src_elt
, dest
);
2173 /* There is no good way to determine how many elements there can be
2174 in a PARALLEL. Since it's fairly cheap, use a really large number. */
2175 #define MAX_SETS (FIRST_PSEUDO_REGISTER * 2)
2177 struct cselib_record_autoinc_data
2179 struct cselib_set
*sets
;
2183 /* Callback for for_each_inc_dec. Records in ARG the SETs implied by
2184 autoinc RTXs: SRC plus SRCOFF if non-NULL is stored in DEST. */
2187 cselib_record_autoinc_cb (rtx mem ATTRIBUTE_UNUSED
, rtx op ATTRIBUTE_UNUSED
,
2188 rtx dest
, rtx src
, rtx srcoff
, void *arg
)
2190 struct cselib_record_autoinc_data
*data
;
2191 data
= (struct cselib_record_autoinc_data
*)arg
;
2193 data
->sets
[data
->n_sets
].dest
= dest
;
2196 data
->sets
[data
->n_sets
].src
= gen_rtx_PLUS (GET_MODE (src
), src
, srcoff
);
2198 data
->sets
[data
->n_sets
].src
= src
;
2205 /* Record the effects of any sets and autoincs in INSN. */
2207 cselib_record_sets (rtx insn
)
2211 struct cselib_set sets
[MAX_SETS
];
2212 rtx body
= PATTERN (insn
);
2214 int n_sets_before_autoinc
;
2215 struct cselib_record_autoinc_data data
;
2217 body
= PATTERN (insn
);
2218 if (GET_CODE (body
) == COND_EXEC
)
2220 cond
= COND_EXEC_TEST (body
);
2221 body
= COND_EXEC_CODE (body
);
2224 /* Find all sets. */
2225 if (GET_CODE (body
) == SET
)
2227 sets
[0].src
= SET_SRC (body
);
2228 sets
[0].dest
= SET_DEST (body
);
2231 else if (GET_CODE (body
) == PARALLEL
)
2233 /* Look through the PARALLEL and record the values being
2234 set, if possible. Also handle any CLOBBERs. */
2235 for (i
= XVECLEN (body
, 0) - 1; i
>= 0; --i
)
2237 rtx x
= XVECEXP (body
, 0, i
);
2239 if (GET_CODE (x
) == SET
)
2241 sets
[n_sets
].src
= SET_SRC (x
);
2242 sets
[n_sets
].dest
= SET_DEST (x
);
2249 && MEM_P (sets
[0].src
)
2250 && !cselib_record_memory
2251 && MEM_READONLY_P (sets
[0].src
))
2253 rtx note
= find_reg_equal_equiv_note (insn
);
2255 if (note
&& CONSTANT_P (XEXP (note
, 0)))
2256 sets
[0].src
= XEXP (note
, 0);
2260 data
.n_sets
= n_sets_before_autoinc
= n_sets
;
2261 for_each_inc_dec (&insn
, cselib_record_autoinc_cb
, &data
);
2262 n_sets
= data
.n_sets
;
2264 /* Look up the values that are read. Do this before invalidating the
2265 locations that are written. */
2266 for (i
= 0; i
< n_sets
; i
++)
2268 rtx dest
= sets
[i
].dest
;
2270 /* A STRICT_LOW_PART can be ignored; we'll record the equivalence for
2271 the low part after invalidating any knowledge about larger modes. */
2272 if (GET_CODE (sets
[i
].dest
) == STRICT_LOW_PART
)
2273 sets
[i
].dest
= dest
= XEXP (dest
, 0);
2275 /* We don't know how to record anything but REG or MEM. */
2277 || (MEM_P (dest
) && cselib_record_memory
))
2279 rtx src
= sets
[i
].src
;
2281 src
= gen_rtx_IF_THEN_ELSE (GET_MODE (dest
), cond
, src
, dest
);
2282 sets
[i
].src_elt
= cselib_lookup (src
, GET_MODE (dest
), 1, VOIDmode
);
2285 enum machine_mode address_mode
2286 = targetm
.addr_space
.address_mode (MEM_ADDR_SPACE (dest
));
2288 sets
[i
].dest_addr_elt
= cselib_lookup (XEXP (dest
, 0),
2293 sets
[i
].dest_addr_elt
= 0;
2297 if (cselib_record_sets_hook
)
2298 cselib_record_sets_hook (insn
, sets
, n_sets
);
2300 /* Invalidate all locations written by this insn. Note that the elts we
2301 looked up in the previous loop aren't affected, just some of their
2302 locations may go away. */
2303 note_stores (body
, cselib_invalidate_rtx_note_stores
, NULL
);
2305 for (i
= n_sets_before_autoinc
; i
< n_sets
; i
++)
2306 cselib_invalidate_rtx (sets
[i
].dest
);
2308 /* If this is an asm, look for duplicate sets. This can happen when the
2309 user uses the same value as an output multiple times. This is valid
2310 if the outputs are not actually used thereafter. Treat this case as
2311 if the value isn't actually set. We do this by smashing the destination
2312 to pc_rtx, so that we won't record the value later. */
2313 if (n_sets
>= 2 && asm_noperands (body
) >= 0)
2315 for (i
= 0; i
< n_sets
; i
++)
2317 rtx dest
= sets
[i
].dest
;
2318 if (REG_P (dest
) || MEM_P (dest
))
2321 for (j
= i
+ 1; j
< n_sets
; j
++)
2322 if (rtx_equal_p (dest
, sets
[j
].dest
))
2324 sets
[i
].dest
= pc_rtx
;
2325 sets
[j
].dest
= pc_rtx
;
2331 /* Now enter the equivalences in our tables. */
2332 for (i
= 0; i
< n_sets
; i
++)
2334 rtx dest
= sets
[i
].dest
;
2336 || (MEM_P (dest
) && cselib_record_memory
))
2337 cselib_record_set (dest
, sets
[i
].src_elt
, sets
[i
].dest_addr_elt
);
2341 /* Record the effects of INSN. */
2344 cselib_process_insn (rtx insn
)
2349 cselib_current_insn
= insn
;
2351 /* Forget everything at a CODE_LABEL, a volatile asm, or a setjmp. */
2354 && find_reg_note (insn
, REG_SETJMP
, NULL
))
2355 || (NONJUMP_INSN_P (insn
)
2356 && GET_CODE (PATTERN (insn
)) == ASM_OPERANDS
2357 && MEM_VOLATILE_P (PATTERN (insn
))))
2359 cselib_reset_table (next_uid
);
2360 cselib_current_insn
= NULL_RTX
;
2364 if (! INSN_P (insn
))
2366 cselib_current_insn
= NULL_RTX
;
2370 /* If this is a call instruction, forget anything stored in a
2371 call clobbered register, or, if this is not a const call, in
2375 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
2376 if (call_used_regs
[i
]
2377 || (REG_VALUES (i
) && REG_VALUES (i
)->elt
2378 && HARD_REGNO_CALL_PART_CLOBBERED (i
,
2379 GET_MODE (REG_VALUES (i
)->elt
->val_rtx
))))
2380 cselib_invalidate_regno (i
, reg_raw_mode
[i
]);
2382 /* Since it is not clear how cselib is going to be used, be
2383 conservative here and treat looping pure or const functions
2384 as if they were regular functions. */
2385 if (RTL_LOOPING_CONST_OR_PURE_CALL_P (insn
)
2386 || !(RTL_CONST_OR_PURE_CALL_P (insn
)))
2387 cselib_invalidate_mem (callmem
);
2390 cselib_record_sets (insn
);
2392 /* Look for any CLOBBERs in CALL_INSN_FUNCTION_USAGE, but only
2393 after we have processed the insn. */
2395 for (x
= CALL_INSN_FUNCTION_USAGE (insn
); x
; x
= XEXP (x
, 1))
2396 if (GET_CODE (XEXP (x
, 0)) == CLOBBER
)
2397 cselib_invalidate_rtx (XEXP (XEXP (x
, 0), 0));
2399 cselib_current_insn
= NULL_RTX
;
2401 if (n_useless_values
> MAX_USELESS_VALUES
2402 /* remove_useless_values is linear in the hash table size. Avoid
2403 quadratic behavior for very large hashtables with very few
2404 useless elements. */
2405 && ((unsigned int)n_useless_values
2406 > (cselib_hash_table
->n_elements
2407 - cselib_hash_table
->n_deleted
2408 - n_debug_values
) / 4))
2409 remove_useless_values ();
2412 /* Initialize cselib for one pass. The caller must also call
2413 init_alias_analysis. */
2416 cselib_init (int record_what
)
2418 elt_list_pool
= create_alloc_pool ("elt_list",
2419 sizeof (struct elt_list
), 10);
2420 elt_loc_list_pool
= create_alloc_pool ("elt_loc_list",
2421 sizeof (struct elt_loc_list
), 10);
2422 cselib_val_pool
= create_alloc_pool ("cselib_val_list",
2423 sizeof (cselib_val
), 10);
2424 value_pool
= create_alloc_pool ("value", RTX_CODE_SIZE (VALUE
), 100);
2425 cselib_record_memory
= record_what
& CSELIB_RECORD_MEMORY
;
2426 cselib_preserve_constants
= record_what
& CSELIB_PRESERVE_CONSTANTS
;
2428 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything,
2429 see canon_true_dependence. This is only created once. */
2431 callmem
= gen_rtx_MEM (BLKmode
, gen_rtx_SCRATCH (VOIDmode
));
2433 cselib_nregs
= max_reg_num ();
2435 /* We preserve reg_values to allow expensive clearing of the whole thing.
2436 Reallocate it however if it happens to be too large. */
2437 if (!reg_values
|| reg_values_size
< cselib_nregs
2438 || (reg_values_size
> 10 && reg_values_size
> cselib_nregs
* 4))
2442 /* Some space for newly emit instructions so we don't end up
2443 reallocating in between passes. */
2444 reg_values_size
= cselib_nregs
+ (63 + cselib_nregs
) / 16;
2445 reg_values
= XCNEWVEC (struct elt_list
*, reg_values_size
);
2447 used_regs
= XNEWVEC (unsigned int, cselib_nregs
);
2449 cselib_hash_table
= htab_create (31, get_value_hash
,
2450 entry_and_rtx_equal_p
, NULL
);
2454 /* Called when the current user is done with cselib. */
2457 cselib_finish (void)
2459 cselib_discard_hook
= NULL
;
2460 cselib_preserve_constants
= false;
2461 cfa_base_preserved_val
= NULL
;
2462 cfa_base_preserved_regno
= INVALID_REGNUM
;
2463 free_alloc_pool (elt_list_pool
);
2464 free_alloc_pool (elt_loc_list_pool
);
2465 free_alloc_pool (cselib_val_pool
);
2466 free_alloc_pool (value_pool
);
2467 cselib_clear_table ();
2468 htab_delete (cselib_hash_table
);
2471 cselib_hash_table
= 0;
2472 n_useless_values
= 0;
2473 n_useless_debug_values
= 0;
2478 /* Dump the cselib_val *X to FILE *info. */
2481 dump_cselib_val (void **x
, void *info
)
2483 cselib_val
*v
= (cselib_val
*)*x
;
2484 FILE *out
= (FILE *)info
;
2485 bool need_lf
= true;
2487 print_inline_rtx (out
, v
->val_rtx
, 0);
2491 struct elt_loc_list
*l
= v
->locs
;
2497 fputs (" locs:", out
);
2500 fprintf (out
, "\n from insn %i ",
2501 INSN_UID (l
->setting_insn
));
2502 print_inline_rtx (out
, l
->loc
, 4);
2504 while ((l
= l
->next
));
2509 fputs (" no locs", out
);
2515 struct elt_list
*e
= v
->addr_list
;
2521 fputs (" addr list:", out
);
2525 print_inline_rtx (out
, e
->elt
->val_rtx
, 2);
2527 while ((e
= e
->next
));
2532 fputs (" no addrs", out
);
2536 if (v
->next_containing_mem
== &dummy_val
)
2537 fputs (" last mem\n", out
);
2538 else if (v
->next_containing_mem
)
2540 fputs (" next mem ", out
);
2541 print_inline_rtx (out
, v
->next_containing_mem
->val_rtx
, 2);
2550 /* Dump to OUT everything in the CSELIB table. */
2553 dump_cselib_table (FILE *out
)
2555 fprintf (out
, "cselib hash table:\n");
2556 htab_traverse (cselib_hash_table
, dump_cselib_val
, out
);
2557 if (first_containing_mem
!= &dummy_val
)
2559 fputs ("first mem ", out
);
2560 print_inline_rtx (out
, first_containing_mem
->val_rtx
, 2);
2563 fprintf (out
, "next uid %i\n", next_uid
);
2566 #include "gt-cselib.h"