1 /* Memory address lowering and addressing mode selection.
2 Copyright (C) 2004, 2006, 2007 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"
46 /* TODO -- handling of symbols (according to Richard Hendersons
47 comments, http://gcc.gnu.org/ml/gcc-patches/2005-04/msg00949.html):
49 There are at least 5 different kinds of symbols that we can run up against:
51 (1) binds_local_p, small data area.
52 (2) binds_local_p, eg local statics
53 (3) !binds_local_p, eg global variables
54 (4) thread local, local_exec
55 (5) thread local, !local_exec
57 Now, (1) won't appear often in an array context, but it certainly can.
58 All you have to do is set -GN high enough, or explicitly mark any
59 random object __attribute__((section (".sdata"))).
61 All of these affect whether or not a symbol is in fact a valid address.
62 The only one tested here is (3). And that result may very well
63 be incorrect for (4) or (5).
65 An incorrect result here does not cause incorrect results out the
66 back end, because the expander in expr.c validizes the address. However
67 it would be nice to improve the handling here in order to produce more
70 /* A "template" for memory address, used to determine whether the address is
73 struct mem_addr_template
GTY (())
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 /* The templates. Each of the five bits of the index corresponds to one
83 component of TARGET_MEM_REF being present, see TEMPL_IDX. */
85 static GTY (()) struct mem_addr_template templates
[32];
87 #define TEMPL_IDX(SYMBOL, BASE, INDEX, STEP, OFFSET) \
88 (((SYMBOL != 0) << 4) \
89 | ((BASE != 0) << 3) \
90 | ((INDEX != 0) << 2) \
91 | ((STEP != 0) << 1) \
94 /* Stores address for memory reference with parameters SYMBOL, BASE, INDEX,
95 STEP and OFFSET to *ADDR. Stores pointers to where step is placed to
96 *STEP_P and offset to *OFFSET_P. */
99 gen_addr_rtx (rtx symbol
, rtx base
, rtx index
, rtx step
, rtx offset
,
100 rtx
*addr
, rtx
**step_p
, rtx
**offset_p
)
115 act_elem
= gen_rtx_MULT (Pmode
, act_elem
, step
);
118 *step_p
= &XEXP (act_elem
, 1);
127 *addr
= simplify_gen_binary (PLUS
, Pmode
, base
, *addr
);
137 act_elem
= gen_rtx_PLUS (Pmode
, act_elem
, offset
);
140 *offset_p
= &XEXP (act_elem
, 1);
142 if (GET_CODE (symbol
) == SYMBOL_REF
143 || GET_CODE (symbol
) == LABEL_REF
144 || GET_CODE (symbol
) == CONST
)
145 act_elem
= gen_rtx_CONST (Pmode
, act_elem
);
149 *addr
= gen_rtx_PLUS (Pmode
, *addr
, act_elem
);
157 *addr
= gen_rtx_PLUS (Pmode
, *addr
, offset
);
159 *offset_p
= &XEXP (*addr
, 1);
173 /* Returns address for TARGET_MEM_REF with parameters given by ADDR.
174 If REALLY_EXPAND is false, just make fake registers instead
175 of really expanding the operands, and perform the expansion in-place
176 by using one of the "templates". */
179 addr_for_mem_ref (struct mem_address
*addr
, bool really_expand
)
181 rtx address
, sym
, bse
, idx
, st
, off
;
182 static bool templates_initialized
= false;
183 struct mem_addr_template
*templ
;
185 if (addr
->step
&& !integer_onep (addr
->step
))
186 st
= immed_double_const (TREE_INT_CST_LOW (addr
->step
),
187 TREE_INT_CST_HIGH (addr
->step
), Pmode
);
191 if (addr
->offset
&& !integer_zerop (addr
->offset
))
192 off
= immed_double_const (TREE_INT_CST_LOW (addr
->offset
),
193 TREE_INT_CST_HIGH (addr
->offset
), Pmode
);
199 /* Reuse the templates for addresses, so that we do not waste memory. */
200 if (!templates_initialized
)
204 templates_initialized
= true;
205 sym
= gen_rtx_SYMBOL_REF (Pmode
, ggc_strdup ("test_symbol"));
206 bse
= gen_raw_REG (Pmode
, LAST_VIRTUAL_REGISTER
+ 1);
207 idx
= gen_raw_REG (Pmode
, LAST_VIRTUAL_REGISTER
+ 2);
209 for (i
= 0; i
< 32; i
++)
210 gen_addr_rtx ((i
& 16 ? sym
: NULL_RTX
),
211 (i
& 8 ? bse
: NULL_RTX
),
212 (i
& 4 ? idx
: NULL_RTX
),
213 (i
& 2 ? const0_rtx
: NULL_RTX
),
214 (i
& 1 ? const0_rtx
: NULL_RTX
),
216 &templates
[i
].step_p
,
217 &templates
[i
].off_p
);
220 templ
= templates
+ TEMPL_IDX (addr
->symbol
, addr
->base
, addr
->index
,
230 /* Otherwise really expand the expressions. */
232 ? expand_expr (build_addr (addr
->symbol
, current_function_decl
),
233 NULL_RTX
, Pmode
, EXPAND_NORMAL
)
236 ? expand_expr (addr
->base
, NULL_RTX
, Pmode
, EXPAND_NORMAL
)
239 ? expand_expr (addr
->index
, NULL_RTX
, Pmode
, EXPAND_NORMAL
)
242 gen_addr_rtx (sym
, bse
, idx
, st
, off
, &address
, NULL
, NULL
);
246 /* Returns address of MEM_REF in TYPE. */
249 tree_mem_ref_addr (tree type
, tree mem_ref
)
253 tree step
= TMR_STEP (mem_ref
), offset
= TMR_OFFSET (mem_ref
);
254 tree sym
= TMR_SYMBOL (mem_ref
), base
= TMR_BASE (mem_ref
);
255 tree addr_base
= NULL_TREE
, addr_off
= NULL_TREE
;
258 addr_base
= fold_convert (type
, build_addr (sym
, current_function_decl
));
259 else if (base
&& POINTER_TYPE_P (TREE_TYPE (base
)))
261 addr_base
= fold_convert (type
, base
);
265 act_elem
= TMR_INDEX (mem_ref
);
269 act_elem
= fold_build2 (MULT_EXPR
, sizetype
, act_elem
, step
);
277 addr_off
= fold_build2 (PLUS_EXPR
, sizetype
, addr_off
, act_elem
);
282 if (offset
&& !integer_zerop (offset
))
285 addr_off
= fold_build2 (PLUS_EXPR
, sizetype
, addr_off
, offset
);
293 addr
= fold_build2 (POINTER_PLUS_EXPR
, type
, addr_base
, addr_off
);
295 addr
= fold_convert (type
, addr_off
);
300 addr
= build_int_cst (type
, 0);
305 /* Returns true if a memory reference in MODE and with parameters given by
306 ADDR is valid on the current target. */
309 valid_mem_ref_p (enum machine_mode mode
, struct mem_address
*addr
)
313 address
= addr_for_mem_ref (addr
, false);
317 return memory_address_p (mode
, address
);
320 /* Checks whether a TARGET_MEM_REF with type TYPE and parameters given by ADDR
321 is valid on the current target and if so, creates and returns the
325 create_mem_ref_raw (tree type
, struct mem_address
*addr
)
327 if (!valid_mem_ref_p (TYPE_MODE (type
), addr
))
330 if (addr
->step
&& integer_onep (addr
->step
))
331 addr
->step
= NULL_TREE
;
333 if (addr
->offset
&& integer_zerop (addr
->offset
))
334 addr
->offset
= NULL_TREE
;
336 return build7 (TARGET_MEM_REF
, type
,
337 addr
->symbol
, addr
->base
, addr
->index
,
338 addr
->step
, addr
->offset
, NULL
, NULL
);
341 /* Returns true if OBJ is an object whose address is a link time constant. */
344 fixed_address_object_p (tree obj
)
346 return (TREE_CODE (obj
) == VAR_DECL
347 && (TREE_STATIC (obj
)
348 || DECL_EXTERNAL (obj
)));
351 /* If ADDR contains an address of object that is a link time constant,
352 move it to PARTS->symbol. */
355 move_fixed_address_to_symbol (struct mem_address
*parts
, aff_tree
*addr
)
358 tree val
= NULL_TREE
;
360 for (i
= 0; i
< addr
->n
; i
++)
362 if (!double_int_one_p (addr
->elts
[i
].coef
))
365 val
= addr
->elts
[i
].val
;
366 if (TREE_CODE (val
) == ADDR_EXPR
367 && fixed_address_object_p (TREE_OPERAND (val
, 0)))
374 parts
->symbol
= TREE_OPERAND (val
, 0);
375 aff_combination_remove_elt (addr
, i
);
378 /* If ADDR contains an address of a dereferenced pointer, move it to
382 move_pointer_to_base (struct mem_address
*parts
, aff_tree
*addr
)
385 tree val
= NULL_TREE
;
387 for (i
= 0; i
< addr
->n
; i
++)
389 if (!double_int_one_p (addr
->elts
[i
].coef
))
392 val
= addr
->elts
[i
].val
;
393 if (POINTER_TYPE_P (TREE_TYPE (val
)))
401 aff_combination_remove_elt (addr
, i
);
404 /* Adds ELT to PARTS. */
407 add_to_parts (struct mem_address
*parts
, tree elt
)
413 parts
->index
= fold_convert (sizetype
, elt
);
423 /* Add ELT to base. */
424 type
= TREE_TYPE (parts
->base
);
425 parts
->base
= fold_build2 (POINTER_PLUS_EXPR
, type
,
427 fold_convert (sizetype
, elt
));
430 /* Finds the most expensive multiplication in ADDR that can be
431 expressed in an addressing mode and move the corresponding
432 element(s) to PARTS. */
435 most_expensive_mult_to_index (struct mem_address
*parts
, aff_tree
*addr
)
438 double_int best_mult
, amult
, amult_neg
;
439 unsigned best_mult_cost
= 0, acost
;
440 tree mult_elt
= NULL_TREE
, elt
;
442 enum tree_code op_code
;
444 best_mult
= double_int_zero
;
445 for (i
= 0; i
< addr
->n
; i
++)
447 if (!double_int_fits_in_shwi_p (addr
->elts
[i
].coef
))
450 /* FIXME: Should use the correct memory mode rather than Pmode. */
452 coef
= double_int_to_shwi (addr
->elts
[i
].coef
);
454 || !multiplier_allowed_in_address_p (coef
, Pmode
))
457 acost
= multiply_by_cost (coef
, Pmode
);
459 if (acost
> best_mult_cost
)
461 best_mult_cost
= acost
;
462 best_mult
= addr
->elts
[i
].coef
;
469 /* Collect elements multiplied by best_mult. */
470 for (i
= j
= 0; i
< addr
->n
; i
++)
472 amult
= addr
->elts
[i
].coef
;
473 amult_neg
= double_int_ext_for_comb (double_int_neg (amult
), addr
);
475 if (double_int_equal_p (amult
, best_mult
))
477 else if (double_int_equal_p (amult_neg
, best_mult
))
478 op_code
= MINUS_EXPR
;
481 addr
->elts
[j
] = addr
->elts
[i
];
486 elt
= fold_convert (sizetype
, addr
->elts
[i
].val
);
488 mult_elt
= fold_build2 (op_code
, sizetype
, mult_elt
, elt
);
489 else if (op_code
== PLUS_EXPR
)
492 mult_elt
= fold_build1 (NEGATE_EXPR
, sizetype
, elt
);
496 parts
->index
= mult_elt
;
497 parts
->step
= double_int_to_tree (sizetype
, best_mult
);
500 /* Splits address ADDR into PARTS.
502 TODO -- be more clever about the distribution of the elements of ADDR
503 to PARTS. Some architectures do not support anything but single
504 register in address, possibly with a small integer offset; while
505 create_mem_ref will simplify the address to an acceptable shape
506 later, it would be more efficient to know that asking for complicated
507 addressing modes is useless. */
510 addr_to_parts (aff_tree
*addr
, struct mem_address
*parts
)
515 parts
->symbol
= NULL_TREE
;
516 parts
->base
= NULL_TREE
;
517 parts
->index
= NULL_TREE
;
518 parts
->step
= NULL_TREE
;
520 if (!double_int_zero_p (addr
->offset
))
521 parts
->offset
= double_int_to_tree (sizetype
, addr
->offset
);
523 parts
->offset
= NULL_TREE
;
525 /* Try to find a symbol. */
526 move_fixed_address_to_symbol (parts
, addr
);
528 /* First move the most expensive feasible multiplication
530 most_expensive_mult_to_index (parts
, addr
);
532 /* Try to find a base of the reference. Since at the moment
533 there is no reliable way how to distinguish between pointer and its
534 offset, this is just a guess. */
536 move_pointer_to_base (parts
, addr
);
538 /* Then try to process the remaining elements. */
539 for (i
= 0; i
< addr
->n
; i
++)
541 part
= fold_convert (sizetype
, addr
->elts
[i
].val
);
542 if (!double_int_one_p (addr
->elts
[i
].coef
))
543 part
= fold_build2 (MULT_EXPR
, sizetype
, part
,
544 double_int_to_tree (sizetype
, addr
->elts
[i
].coef
));
545 add_to_parts (parts
, part
);
548 add_to_parts (parts
, fold_convert (sizetype
, addr
->rest
));
551 /* Force the PARTS to register. */
554 gimplify_mem_ref_parts (block_stmt_iterator
*bsi
, struct mem_address
*parts
)
557 parts
->base
= force_gimple_operand_bsi (bsi
, parts
->base
,
559 true, BSI_SAME_STMT
);
561 parts
->index
= force_gimple_operand_bsi (bsi
, parts
->index
,
563 true, BSI_SAME_STMT
);
566 /* Creates and returns a TARGET_MEM_REF for address ADDR. If necessary
567 computations are emitted in front of BSI. TYPE is the mode
568 of created memory reference. */
571 create_mem_ref (block_stmt_iterator
*bsi
, tree type
, aff_tree
*addr
)
575 struct mem_address parts
;
577 addr_to_parts (addr
, &parts
);
578 gimplify_mem_ref_parts (bsi
, &parts
);
579 mem_ref
= create_mem_ref_raw (type
, &parts
);
583 /* The expression is too complicated. Try making it simpler. */
585 if (parts
.step
&& !integer_onep (parts
.step
))
587 /* Move the multiplication to index. */
588 gcc_assert (parts
.index
);
589 parts
.index
= force_gimple_operand_bsi (bsi
,
590 fold_build2 (MULT_EXPR
, sizetype
,
591 parts
.index
, parts
.step
),
592 true, NULL_TREE
, true, BSI_SAME_STMT
);
593 parts
.step
= NULL_TREE
;
595 mem_ref
= create_mem_ref_raw (type
, &parts
);
602 tmp
= build_addr (parts
.symbol
, current_function_decl
);
603 gcc_assert (is_gimple_val (tmp
));
605 /* Add the symbol to base, eventually forcing it to register. */
608 gcc_assert (useless_type_conversion_p
609 (sizetype
, TREE_TYPE (parts
.base
)));
613 atype
= TREE_TYPE (tmp
);
614 parts
.base
= force_gimple_operand_bsi (bsi
,
615 fold_build2 (PLUS_EXPR
, atype
,
616 fold_convert (atype
, parts
.base
),
618 true, NULL_TREE
, true, BSI_SAME_STMT
);
622 parts
.index
= parts
.base
;
628 parts
.symbol
= NULL_TREE
;
630 mem_ref
= create_mem_ref_raw (type
, &parts
);
637 /* Add index to base. */
640 atype
= TREE_TYPE (parts
.base
);
641 parts
.base
= force_gimple_operand_bsi (bsi
,
642 fold_build2 (PLUS_EXPR
, atype
,
644 fold_convert (atype
, parts
.index
)),
645 true, NULL_TREE
, true, BSI_SAME_STMT
);
648 parts
.base
= parts
.index
;
649 parts
.index
= NULL_TREE
;
651 mem_ref
= create_mem_ref_raw (type
, &parts
);
656 if (parts
.offset
&& !integer_zerop (parts
.offset
))
658 /* Try adding offset to base. */
661 atype
= TREE_TYPE (parts
.base
);
662 parts
.base
= force_gimple_operand_bsi (bsi
,
663 fold_build2 (POINTER_PLUS_EXPR
, atype
,
665 fold_convert (sizetype
, parts
.offset
)),
666 true, NULL_TREE
, true, BSI_SAME_STMT
);
669 parts
.base
= parts
.offset
;
671 parts
.offset
= NULL_TREE
;
673 mem_ref
= create_mem_ref_raw (type
, &parts
);
678 /* Verify that the address is in the simplest possible shape
679 (only a register). If we cannot create such a memory reference,
680 something is really wrong. */
681 gcc_assert (parts
.symbol
== NULL_TREE
);
682 gcc_assert (parts
.index
== NULL_TREE
);
683 gcc_assert (!parts
.step
|| integer_onep (parts
.step
));
684 gcc_assert (!parts
.offset
|| integer_zerop (parts
.offset
));
688 /* Copies components of the address from OP to ADDR. */
691 get_address_description (tree op
, struct mem_address
*addr
)
693 addr
->symbol
= TMR_SYMBOL (op
);
694 addr
->base
= TMR_BASE (op
);
695 addr
->index
= TMR_INDEX (op
);
696 addr
->step
= TMR_STEP (op
);
697 addr
->offset
= TMR_OFFSET (op
);
700 /* Copies the additional information attached to target_mem_ref FROM to TO. */
703 copy_mem_ref_info (tree to
, tree from
)
705 /* Copy the annotation, to preserve the aliasing information. */
706 TMR_TAG (to
) = TMR_TAG (from
);
708 /* And the info about the original reference. */
709 TMR_ORIGINAL (to
) = TMR_ORIGINAL (from
);
712 /* Move constants in target_mem_ref REF to offset. Returns the new target
713 mem ref if anything changes, NULL_TREE otherwise. */
716 maybe_fold_tmr (tree ref
)
718 struct mem_address addr
;
719 bool changed
= false;
722 get_address_description (ref
, &addr
);
724 if (addr
.base
&& TREE_CODE (addr
.base
) == INTEGER_CST
)
727 addr
.offset
= fold_binary_to_constant (PLUS_EXPR
, sizetype
,
729 fold_convert (sizetype
, addr
.base
));
731 addr
.offset
= addr
.base
;
733 addr
.base
= NULL_TREE
;
737 if (addr
.index
&& TREE_CODE (addr
.index
) == INTEGER_CST
)
742 off
= fold_binary_to_constant (MULT_EXPR
, sizetype
,
744 addr
.step
= NULL_TREE
;
749 addr
.offset
= fold_binary_to_constant (PLUS_EXPR
, sizetype
,
755 addr
.index
= NULL_TREE
;
762 ret
= create_mem_ref_raw (TREE_TYPE (ref
), &addr
);
766 copy_mem_ref_info (ret
, ref
);
770 /* Dump PARTS to FILE. */
772 extern void dump_mem_address (FILE *, struct mem_address
*);
774 dump_mem_address (FILE *file
, struct mem_address
*parts
)
778 fprintf (file
, "symbol: ");
779 print_generic_expr (file
, parts
->symbol
, TDF_SLIM
);
780 fprintf (file
, "\n");
784 fprintf (file
, "base: ");
785 print_generic_expr (file
, parts
->base
, TDF_SLIM
);
786 fprintf (file
, "\n");
790 fprintf (file
, "index: ");
791 print_generic_expr (file
, parts
->index
, TDF_SLIM
);
792 fprintf (file
, "\n");
796 fprintf (file
, "step: ");
797 print_generic_expr (file
, parts
->step
, TDF_SLIM
);
798 fprintf (file
, "\n");
802 fprintf (file
, "offset: ");
803 print_generic_expr (file
, parts
->offset
, TDF_SLIM
);
804 fprintf (file
, "\n");
808 #include "gt-tree-ssa-address.h"