1 /* Memory address lowering and addressing mode selection.
2 Copyright (C) 2004, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 3, or (at your option) any
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* Utility functions for manipulation with TARGET_MEM_REFs -- tree expressions
21 that directly map to addressing modes of the target. */
25 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
33 #include "diagnostic.h"
34 #include "tree-flow.h"
35 #include "tree-dump.h"
36 #include "tree-pass.h"
39 #include "tree-inline.h"
40 #include "insn-config.h"
44 #include "tree-affine.h"
47 /* TODO -- handling of symbols (according to Richard Hendersons
48 comments, http://gcc.gnu.org/ml/gcc-patches/2005-04/msg00949.html):
50 There are at least 5 different kinds of symbols that we can run up against:
52 (1) binds_local_p, small data area.
53 (2) binds_local_p, eg local statics
54 (3) !binds_local_p, eg global variables
55 (4) thread local, local_exec
56 (5) thread local, !local_exec
58 Now, (1) won't appear often in an array context, but it certainly can.
59 All you have to do is set -GN high enough, or explicitly mark any
60 random object __attribute__((section (".sdata"))).
62 All of these affect whether or not a symbol is in fact a valid address.
63 The only one tested here is (3). And that result may very well
64 be incorrect for (4) or (5).
66 An incorrect result here does not cause incorrect results out the
67 back end, because the expander in expr.c validizes the address. However
68 it would be nice to improve the handling here in order to produce more
71 /* A "template" for memory address, used to determine whether the address is
74 typedef struct GTY (()) mem_addr_template
{
75 rtx ref
; /* The template. */
76 rtx
* GTY ((skip
)) step_p
; /* The point in template where the step should be
78 rtx
* GTY ((skip
)) off_p
; /* The point in template where the offset should
82 DEF_VEC_O (mem_addr_template
);
83 DEF_VEC_ALLOC_O (mem_addr_template
, gc
);
85 /* The templates. Each of the low five bits of the index corresponds to one
86 component of TARGET_MEM_REF being present, while the high bits identify
87 the address space. See TEMPL_IDX. */
89 static GTY(()) VEC (mem_addr_template
, gc
) *mem_addr_template_list
;
91 #define TEMPL_IDX(AS, SYMBOL, BASE, INDEX, STEP, OFFSET) \
93 | ((SYMBOL != 0) << 4) \
94 | ((BASE != 0) << 3) \
95 | ((INDEX != 0) << 2) \
96 | ((STEP != 0) << 1) \
99 /* Stores address for memory reference with parameters SYMBOL, BASE, INDEX,
100 STEP and OFFSET to *ADDR using address mode ADDRESS_MODE. Stores pointers
101 to where step is placed to *STEP_P and offset to *OFFSET_P. */
104 gen_addr_rtx (enum machine_mode address_mode
,
105 rtx symbol
, rtx base
, rtx index
, rtx step
, rtx offset
,
106 rtx
*addr
, rtx
**step_p
, rtx
**offset_p
)
121 act_elem
= gen_rtx_MULT (address_mode
, act_elem
, step
);
124 *step_p
= &XEXP (act_elem
, 1);
133 *addr
= simplify_gen_binary (PLUS
, address_mode
, base
, *addr
);
143 act_elem
= gen_rtx_PLUS (address_mode
, act_elem
, offset
);
146 *offset_p
= &XEXP (act_elem
, 1);
148 if (GET_CODE (symbol
) == SYMBOL_REF
149 || GET_CODE (symbol
) == LABEL_REF
150 || GET_CODE (symbol
) == CONST
)
151 act_elem
= gen_rtx_CONST (address_mode
, act_elem
);
155 *addr
= gen_rtx_PLUS (address_mode
, *addr
, act_elem
);
163 *addr
= gen_rtx_PLUS (address_mode
, *addr
, offset
);
165 *offset_p
= &XEXP (*addr
, 1);
179 /* Returns address for TARGET_MEM_REF with parameters given by ADDR
181 If REALLY_EXPAND is false, just make fake registers instead
182 of really expanding the operands, and perform the expansion in-place
183 by using one of the "templates". */
186 addr_for_mem_ref (struct mem_address
*addr
, addr_space_t as
,
189 enum machine_mode address_mode
= targetm
.addr_space
.address_mode (as
);
190 rtx address
, sym
, bse
, idx
, st
, off
;
191 struct mem_addr_template
*templ
;
193 if (addr
->step
&& !integer_onep (addr
->step
))
194 st
= immed_double_const (TREE_INT_CST_LOW (addr
->step
),
195 TREE_INT_CST_HIGH (addr
->step
), address_mode
);
199 if (addr
->offset
&& !integer_zerop (addr
->offset
))
200 off
= immed_double_const (TREE_INT_CST_LOW (addr
->offset
),
201 TREE_INT_CST_HIGH (addr
->offset
), address_mode
);
207 unsigned int templ_index
208 = TEMPL_IDX (as
, addr
->symbol
, addr
->base
, addr
->index
, st
, off
);
211 >= VEC_length (mem_addr_template
, mem_addr_template_list
))
212 VEC_safe_grow_cleared (mem_addr_template
, gc
, mem_addr_template_list
,
215 /* Reuse the templates for addresses, so that we do not waste memory. */
216 templ
= VEC_index (mem_addr_template
, mem_addr_template_list
, templ_index
);
219 sym
= (addr
->symbol
?
220 gen_rtx_SYMBOL_REF (address_mode
, ggc_strdup ("test_symbol"))
223 gen_raw_REG (address_mode
, LAST_VIRTUAL_REGISTER
+ 1)
226 gen_raw_REG (address_mode
, LAST_VIRTUAL_REGISTER
+ 2)
229 gen_addr_rtx (address_mode
, sym
, bse
, idx
,
230 st
? const0_rtx
: NULL_RTX
,
231 off
? const0_rtx
: NULL_RTX
,
245 /* Otherwise really expand the expressions. */
247 ? expand_expr (build_addr (addr
->symbol
, current_function_decl
),
248 NULL_RTX
, address_mode
, EXPAND_NORMAL
)
251 ? expand_expr (addr
->base
, NULL_RTX
, address_mode
, EXPAND_NORMAL
)
254 ? expand_expr (addr
->index
, NULL_RTX
, address_mode
, EXPAND_NORMAL
)
257 gen_addr_rtx (address_mode
, sym
, bse
, idx
, st
, off
, &address
, NULL
, NULL
);
261 /* Returns address of MEM_REF in TYPE. */
264 tree_mem_ref_addr (tree type
, tree mem_ref
)
268 tree step
= TMR_STEP (mem_ref
), offset
= TMR_OFFSET (mem_ref
);
269 tree sym
= TMR_SYMBOL (mem_ref
), base
= TMR_BASE (mem_ref
);
270 tree addr_base
= NULL_TREE
, addr_off
= NULL_TREE
;
273 addr_base
= fold_convert (type
, build_addr (sym
, current_function_decl
));
274 else if (base
&& POINTER_TYPE_P (TREE_TYPE (base
)))
276 addr_base
= fold_convert (type
, base
);
280 act_elem
= TMR_INDEX (mem_ref
);
284 act_elem
= fold_build2 (MULT_EXPR
, sizetype
, act_elem
, step
);
292 addr_off
= fold_build2 (PLUS_EXPR
, sizetype
, addr_off
, act_elem
);
297 if (offset
&& !integer_zerop (offset
))
300 addr_off
= fold_build2 (PLUS_EXPR
, sizetype
, addr_off
, offset
);
308 addr
= fold_build2 (POINTER_PLUS_EXPR
, type
, addr_base
, addr_off
);
310 addr
= fold_convert (type
, addr_off
);
315 addr
= build_int_cst (type
, 0);
320 /* Returns true if a memory reference in MODE and with parameters given by
321 ADDR is valid on the current target. */
324 valid_mem_ref_p (enum machine_mode mode
, addr_space_t as
,
325 struct mem_address
*addr
)
329 address
= addr_for_mem_ref (addr
, as
, false);
333 return memory_address_addr_space_p (mode
, address
, as
);
336 /* Checks whether a TARGET_MEM_REF with type TYPE and parameters given by ADDR
337 is valid on the current target and if so, creates and returns the
341 create_mem_ref_raw (tree type
, struct mem_address
*addr
)
343 if (!valid_mem_ref_p (TYPE_MODE (type
), TYPE_ADDR_SPACE (type
), addr
))
346 if (addr
->step
&& integer_onep (addr
->step
))
347 addr
->step
= NULL_TREE
;
349 if (addr
->offset
&& integer_zerop (addr
->offset
))
350 addr
->offset
= NULL_TREE
;
352 return build6 (TARGET_MEM_REF
, type
,
353 addr
->symbol
, addr
->base
, addr
->index
,
354 addr
->step
, addr
->offset
, NULL
);
357 /* Returns true if OBJ is an object whose address is a link time constant. */
360 fixed_address_object_p (tree obj
)
362 return (TREE_CODE (obj
) == VAR_DECL
363 && (TREE_STATIC (obj
)
364 || DECL_EXTERNAL (obj
))
365 && ! DECL_DLLIMPORT_P (obj
));
368 /* If ADDR contains an address of object that is a link time constant,
369 move it to PARTS->symbol. */
372 move_fixed_address_to_symbol (struct mem_address
*parts
, aff_tree
*addr
)
375 tree val
= NULL_TREE
;
377 for (i
= 0; i
< addr
->n
; i
++)
379 if (!double_int_one_p (addr
->elts
[i
].coef
))
382 val
= addr
->elts
[i
].val
;
383 if (TREE_CODE (val
) == ADDR_EXPR
384 && fixed_address_object_p (TREE_OPERAND (val
, 0)))
391 parts
->symbol
= TREE_OPERAND (val
, 0);
392 aff_combination_remove_elt (addr
, i
);
395 /* If ADDR contains an instance of BASE_HINT, move it to PARTS->base. */
398 move_hint_to_base (tree type
, struct mem_address
*parts
, tree base_hint
,
402 tree val
= NULL_TREE
;
405 for (i
= 0; i
< addr
->n
; i
++)
407 if (!double_int_one_p (addr
->elts
[i
].coef
))
410 val
= addr
->elts
[i
].val
;
411 if (operand_equal_p (val
, base_hint
, 0))
418 /* Cast value to appropriate pointer type. We cannot use a pointer
419 to TYPE directly, as the back-end will assume registers of pointer
420 type are aligned, and just the base itself may not actually be.
421 We use void pointer to the type's address space instead. */
422 qual
= ENCODE_QUAL_ADDR_SPACE (TYPE_ADDR_SPACE (type
));
423 type
= build_qualified_type (void_type_node
, qual
);
424 parts
->base
= fold_convert (build_pointer_type (type
), val
);
425 aff_combination_remove_elt (addr
, i
);
428 /* If ADDR contains an address of a dereferenced pointer, move it to
432 move_pointer_to_base (struct mem_address
*parts
, aff_tree
*addr
)
435 tree val
= NULL_TREE
;
437 for (i
= 0; i
< addr
->n
; i
++)
439 if (!double_int_one_p (addr
->elts
[i
].coef
))
442 val
= addr
->elts
[i
].val
;
443 if (POINTER_TYPE_P (TREE_TYPE (val
)))
451 aff_combination_remove_elt (addr
, i
);
454 /* Adds ELT to PARTS. */
457 add_to_parts (struct mem_address
*parts
, tree elt
)
463 parts
->index
= fold_convert (sizetype
, elt
);
473 /* Add ELT to base. */
474 type
= TREE_TYPE (parts
->base
);
475 if (POINTER_TYPE_P (type
))
476 parts
->base
= fold_build2 (POINTER_PLUS_EXPR
, type
,
478 fold_convert (sizetype
, elt
));
480 parts
->base
= fold_build2 (PLUS_EXPR
, type
,
484 /* Finds the most expensive multiplication in ADDR that can be
485 expressed in an addressing mode and move the corresponding
486 element(s) to PARTS. */
489 most_expensive_mult_to_index (tree type
, struct mem_address
*parts
,
490 aff_tree
*addr
, bool speed
)
492 addr_space_t as
= TYPE_ADDR_SPACE (type
);
493 enum machine_mode address_mode
= targetm
.addr_space
.address_mode (as
);
495 double_int best_mult
, amult
, amult_neg
;
496 unsigned best_mult_cost
= 0, acost
;
497 tree mult_elt
= NULL_TREE
, elt
;
499 enum tree_code op_code
;
501 best_mult
= double_int_zero
;
502 for (i
= 0; i
< addr
->n
; i
++)
504 if (!double_int_fits_in_shwi_p (addr
->elts
[i
].coef
))
507 coef
= double_int_to_shwi (addr
->elts
[i
].coef
);
509 || !multiplier_allowed_in_address_p (coef
, TYPE_MODE (type
), as
))
512 acost
= multiply_by_cost (coef
, address_mode
, speed
);
514 if (acost
> best_mult_cost
)
516 best_mult_cost
= acost
;
517 best_mult
= addr
->elts
[i
].coef
;
524 /* Collect elements multiplied by best_mult. */
525 for (i
= j
= 0; i
< addr
->n
; i
++)
527 amult
= addr
->elts
[i
].coef
;
528 amult_neg
= double_int_ext_for_comb (double_int_neg (amult
), addr
);
530 if (double_int_equal_p (amult
, best_mult
))
532 else if (double_int_equal_p (amult_neg
, best_mult
))
533 op_code
= MINUS_EXPR
;
536 addr
->elts
[j
] = addr
->elts
[i
];
541 elt
= fold_convert (sizetype
, addr
->elts
[i
].val
);
543 mult_elt
= fold_build2 (op_code
, sizetype
, mult_elt
, elt
);
544 else if (op_code
== PLUS_EXPR
)
547 mult_elt
= fold_build1 (NEGATE_EXPR
, sizetype
, elt
);
551 parts
->index
= mult_elt
;
552 parts
->step
= double_int_to_tree (sizetype
, best_mult
);
555 /* Splits address ADDR for a memory access of type TYPE into PARTS.
556 If BASE_HINT is non-NULL, it specifies an SSA name to be used
557 preferentially as base of the reference.
559 TODO -- be more clever about the distribution of the elements of ADDR
560 to PARTS. Some architectures do not support anything but single
561 register in address, possibly with a small integer offset; while
562 create_mem_ref will simplify the address to an acceptable shape
563 later, it would be more efficient to know that asking for complicated
564 addressing modes is useless. */
567 addr_to_parts (tree type
, aff_tree
*addr
, tree base_hint
,
568 struct mem_address
*parts
, bool speed
)
573 parts
->symbol
= NULL_TREE
;
574 parts
->base
= NULL_TREE
;
575 parts
->index
= NULL_TREE
;
576 parts
->step
= NULL_TREE
;
578 if (!double_int_zero_p (addr
->offset
))
579 parts
->offset
= double_int_to_tree (sizetype
, addr
->offset
);
581 parts
->offset
= NULL_TREE
;
583 /* Try to find a symbol. */
584 move_fixed_address_to_symbol (parts
, addr
);
586 /* First move the most expensive feasible multiplication
588 most_expensive_mult_to_index (type
, parts
, addr
, speed
);
590 /* Try to find a base of the reference. Since at the moment
591 there is no reliable way how to distinguish between pointer and its
592 offset, this is just a guess. */
593 if (!parts
->symbol
&& base_hint
)
594 move_hint_to_base (type
, parts
, base_hint
, addr
);
595 if (!parts
->symbol
&& !parts
->base
)
596 move_pointer_to_base (parts
, addr
);
598 /* Then try to process the remaining elements. */
599 for (i
= 0; i
< addr
->n
; i
++)
601 part
= fold_convert (sizetype
, addr
->elts
[i
].val
);
602 if (!double_int_one_p (addr
->elts
[i
].coef
))
603 part
= fold_build2 (MULT_EXPR
, sizetype
, part
,
604 double_int_to_tree (sizetype
, addr
->elts
[i
].coef
));
605 add_to_parts (parts
, part
);
608 add_to_parts (parts
, fold_convert (sizetype
, addr
->rest
));
611 /* Force the PARTS to register. */
614 gimplify_mem_ref_parts (gimple_stmt_iterator
*gsi
, struct mem_address
*parts
)
617 parts
->base
= force_gimple_operand_gsi (gsi
, parts
->base
,
619 true, GSI_SAME_STMT
);
621 parts
->index
= force_gimple_operand_gsi (gsi
, parts
->index
,
623 true, GSI_SAME_STMT
);
626 /* Creates and returns a TARGET_MEM_REF for address ADDR. If necessary
627 computations are emitted in front of GSI. TYPE is the mode
628 of created memory reference. */
631 create_mem_ref (gimple_stmt_iterator
*gsi
, tree type
, aff_tree
*addr
,
632 tree base_hint
, bool speed
)
636 struct mem_address parts
;
638 addr_to_parts (type
, addr
, base_hint
, &parts
, speed
);
639 gimplify_mem_ref_parts (gsi
, &parts
);
640 mem_ref
= create_mem_ref_raw (type
, &parts
);
644 /* The expression is too complicated. Try making it simpler. */
646 if (parts
.step
&& !integer_onep (parts
.step
))
648 /* Move the multiplication to index. */
649 gcc_assert (parts
.index
);
650 parts
.index
= force_gimple_operand_gsi (gsi
,
651 fold_build2 (MULT_EXPR
, sizetype
,
652 parts
.index
, parts
.step
),
653 true, NULL_TREE
, true, GSI_SAME_STMT
);
654 parts
.step
= NULL_TREE
;
656 mem_ref
= create_mem_ref_raw (type
, &parts
);
663 tmp
= build_addr (parts
.symbol
, current_function_decl
);
664 gcc_assert (is_gimple_val (tmp
));
666 /* Add the symbol to base, eventually forcing it to register. */
669 gcc_assert (useless_type_conversion_p
670 (sizetype
, TREE_TYPE (parts
.base
)));
674 atype
= TREE_TYPE (tmp
);
675 parts
.base
= force_gimple_operand_gsi (gsi
,
676 fold_build2 (POINTER_PLUS_EXPR
, atype
,
678 fold_convert (sizetype
, parts
.base
)),
679 true, NULL_TREE
, true, GSI_SAME_STMT
);
683 parts
.index
= parts
.base
;
689 parts
.symbol
= NULL_TREE
;
691 mem_ref
= create_mem_ref_raw (type
, &parts
);
698 /* Add index to base. */
701 atype
= TREE_TYPE (parts
.base
);
702 parts
.base
= force_gimple_operand_gsi (gsi
,
703 fold_build2 (POINTER_PLUS_EXPR
, atype
,
706 true, NULL_TREE
, true, GSI_SAME_STMT
);
709 parts
.base
= parts
.index
;
710 parts
.index
= NULL_TREE
;
712 mem_ref
= create_mem_ref_raw (type
, &parts
);
717 if (parts
.offset
&& !integer_zerop (parts
.offset
))
719 /* Try adding offset to base. */
722 atype
= TREE_TYPE (parts
.base
);
723 parts
.base
= force_gimple_operand_gsi (gsi
,
724 fold_build2 (POINTER_PLUS_EXPR
, atype
,
726 fold_convert (sizetype
, parts
.offset
)),
727 true, NULL_TREE
, true, GSI_SAME_STMT
);
730 parts
.base
= parts
.offset
;
732 parts
.offset
= NULL_TREE
;
734 mem_ref
= create_mem_ref_raw (type
, &parts
);
739 /* Verify that the address is in the simplest possible shape
740 (only a register). If we cannot create such a memory reference,
741 something is really wrong. */
742 gcc_assert (parts
.symbol
== NULL_TREE
);
743 gcc_assert (parts
.index
== NULL_TREE
);
744 gcc_assert (!parts
.step
|| integer_onep (parts
.step
));
745 gcc_assert (!parts
.offset
|| integer_zerop (parts
.offset
));
749 /* Copies components of the address from OP to ADDR. */
752 get_address_description (tree op
, struct mem_address
*addr
)
754 addr
->symbol
= TMR_SYMBOL (op
);
755 addr
->base
= TMR_BASE (op
);
756 addr
->index
= TMR_INDEX (op
);
757 addr
->step
= TMR_STEP (op
);
758 addr
->offset
= TMR_OFFSET (op
);
761 /* Copies the additional information attached to target_mem_ref FROM to TO. */
764 copy_mem_ref_info (tree to
, tree from
)
766 /* And the info about the original reference. */
767 TMR_ORIGINAL (to
) = TMR_ORIGINAL (from
);
770 /* Move constants in target_mem_ref REF to offset. Returns the new target
771 mem ref if anything changes, NULL_TREE otherwise. */
774 maybe_fold_tmr (tree ref
)
776 struct mem_address addr
;
777 bool changed
= false;
780 get_address_description (ref
, &addr
);
782 if (addr
.base
&& TREE_CODE (addr
.base
) == INTEGER_CST
)
785 addr
.offset
= fold_binary_to_constant (PLUS_EXPR
, sizetype
,
787 fold_convert (sizetype
, addr
.base
));
789 addr
.offset
= addr
.base
;
791 addr
.base
= NULL_TREE
;
795 if (addr
.index
&& TREE_CODE (addr
.index
) == INTEGER_CST
)
800 off
= fold_binary_to_constant (MULT_EXPR
, sizetype
,
802 addr
.step
= NULL_TREE
;
807 addr
.offset
= fold_binary_to_constant (PLUS_EXPR
, sizetype
,
813 addr
.index
= NULL_TREE
;
820 ret
= create_mem_ref_raw (TREE_TYPE (ref
), &addr
);
824 copy_mem_ref_info (ret
, ref
);
828 /* Dump PARTS to FILE. */
830 extern void dump_mem_address (FILE *, struct mem_address
*);
832 dump_mem_address (FILE *file
, struct mem_address
*parts
)
836 fprintf (file
, "symbol: ");
837 print_generic_expr (file
, parts
->symbol
, TDF_SLIM
);
838 fprintf (file
, "\n");
842 fprintf (file
, "base: ");
843 print_generic_expr (file
, parts
->base
, TDF_SLIM
);
844 fprintf (file
, "\n");
848 fprintf (file
, "index: ");
849 print_generic_expr (file
, parts
->index
, TDF_SLIM
);
850 fprintf (file
, "\n");
854 fprintf (file
, "step: ");
855 print_generic_expr (file
, parts
->step
, TDF_SLIM
);
856 fprintf (file
, "\n");
860 fprintf (file
, "offset: ");
861 print_generic_expr (file
, parts
->offset
, TDF_SLIM
);
862 fprintf (file
, "\n");
866 #include "gt-tree-ssa-address.h"