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"
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 build6 (TARGET_MEM_REF
, type
,
337 addr
->symbol
, addr
->base
, addr
->index
,
338 addr
->step
, addr
->offset
, 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
))
349 && ! DECL_DLLIMPORT_P (obj
));
352 /* If ADDR contains an address of object that is a link time constant,
353 move it to PARTS->symbol. */
356 move_fixed_address_to_symbol (struct mem_address
*parts
, aff_tree
*addr
)
359 tree val
= NULL_TREE
;
361 for (i
= 0; i
< addr
->n
; i
++)
363 if (!double_int_one_p (addr
->elts
[i
].coef
))
366 val
= addr
->elts
[i
].val
;
367 if (TREE_CODE (val
) == ADDR_EXPR
368 && fixed_address_object_p (TREE_OPERAND (val
, 0)))
375 parts
->symbol
= TREE_OPERAND (val
, 0);
376 aff_combination_remove_elt (addr
, i
);
379 /* If ADDR contains an address of a dereferenced pointer, move it to
383 move_pointer_to_base (struct mem_address
*parts
, aff_tree
*addr
)
386 tree val
= NULL_TREE
;
388 for (i
= 0; i
< addr
->n
; i
++)
390 if (!double_int_one_p (addr
->elts
[i
].coef
))
393 val
= addr
->elts
[i
].val
;
394 if (POINTER_TYPE_P (TREE_TYPE (val
)))
402 aff_combination_remove_elt (addr
, i
);
405 /* Adds ELT to PARTS. */
408 add_to_parts (struct mem_address
*parts
, tree elt
)
414 parts
->index
= fold_convert (sizetype
, elt
);
424 /* Add ELT to base. */
425 type
= TREE_TYPE (parts
->base
);
426 if (POINTER_TYPE_P (type
))
427 parts
->base
= fold_build2 (POINTER_PLUS_EXPR
, type
,
429 fold_convert (sizetype
, elt
));
431 parts
->base
= fold_build2 (PLUS_EXPR
, type
,
435 /* Finds the most expensive multiplication in ADDR that can be
436 expressed in an addressing mode and move the corresponding
437 element(s) to PARTS. */
440 most_expensive_mult_to_index (struct mem_address
*parts
, aff_tree
*addr
,
444 double_int best_mult
, amult
, amult_neg
;
445 unsigned best_mult_cost
= 0, acost
;
446 tree mult_elt
= NULL_TREE
, elt
;
448 enum tree_code op_code
;
450 best_mult
= double_int_zero
;
451 for (i
= 0; i
< addr
->n
; i
++)
453 if (!double_int_fits_in_shwi_p (addr
->elts
[i
].coef
))
456 /* FIXME: Should use the correct memory mode rather than Pmode. */
458 coef
= double_int_to_shwi (addr
->elts
[i
].coef
);
460 || !multiplier_allowed_in_address_p (coef
, Pmode
))
463 acost
= multiply_by_cost (coef
, Pmode
, speed
);
465 if (acost
> best_mult_cost
)
467 best_mult_cost
= acost
;
468 best_mult
= addr
->elts
[i
].coef
;
475 /* Collect elements multiplied by best_mult. */
476 for (i
= j
= 0; i
< addr
->n
; i
++)
478 amult
= addr
->elts
[i
].coef
;
479 amult_neg
= double_int_ext_for_comb (double_int_neg (amult
), addr
);
481 if (double_int_equal_p (amult
, best_mult
))
483 else if (double_int_equal_p (amult_neg
, best_mult
))
484 op_code
= MINUS_EXPR
;
487 addr
->elts
[j
] = addr
->elts
[i
];
492 elt
= fold_convert (sizetype
, addr
->elts
[i
].val
);
494 mult_elt
= fold_build2 (op_code
, sizetype
, mult_elt
, elt
);
495 else if (op_code
== PLUS_EXPR
)
498 mult_elt
= fold_build1 (NEGATE_EXPR
, sizetype
, elt
);
502 parts
->index
= mult_elt
;
503 parts
->step
= double_int_to_tree (sizetype
, best_mult
);
506 /* Splits address ADDR into PARTS.
508 TODO -- be more clever about the distribution of the elements of ADDR
509 to PARTS. Some architectures do not support anything but single
510 register in address, possibly with a small integer offset; while
511 create_mem_ref will simplify the address to an acceptable shape
512 later, it would be more efficient to know that asking for complicated
513 addressing modes is useless. */
516 addr_to_parts (aff_tree
*addr
, struct mem_address
*parts
, bool speed
)
521 parts
->symbol
= NULL_TREE
;
522 parts
->base
= NULL_TREE
;
523 parts
->index
= NULL_TREE
;
524 parts
->step
= NULL_TREE
;
526 if (!double_int_zero_p (addr
->offset
))
527 parts
->offset
= double_int_to_tree (sizetype
, addr
->offset
);
529 parts
->offset
= NULL_TREE
;
531 /* Try to find a symbol. */
532 move_fixed_address_to_symbol (parts
, addr
);
534 /* First move the most expensive feasible multiplication
536 most_expensive_mult_to_index (parts
, addr
, speed
);
538 /* Try to find a base of the reference. Since at the moment
539 there is no reliable way how to distinguish between pointer and its
540 offset, this is just a guess. */
542 move_pointer_to_base (parts
, addr
);
544 /* Then try to process the remaining elements. */
545 for (i
= 0; i
< addr
->n
; i
++)
547 part
= fold_convert (sizetype
, addr
->elts
[i
].val
);
548 if (!double_int_one_p (addr
->elts
[i
].coef
))
549 part
= fold_build2 (MULT_EXPR
, sizetype
, part
,
550 double_int_to_tree (sizetype
, addr
->elts
[i
].coef
));
551 add_to_parts (parts
, part
);
554 add_to_parts (parts
, fold_convert (sizetype
, addr
->rest
));
557 /* Force the PARTS to register. */
560 gimplify_mem_ref_parts (gimple_stmt_iterator
*gsi
, struct mem_address
*parts
)
563 parts
->base
= force_gimple_operand_gsi (gsi
, parts
->base
,
565 true, GSI_SAME_STMT
);
567 parts
->index
= force_gimple_operand_gsi (gsi
, parts
->index
,
569 true, GSI_SAME_STMT
);
572 /* Creates and returns a TARGET_MEM_REF for address ADDR. If necessary
573 computations are emitted in front of GSI. TYPE is the mode
574 of created memory reference. */
577 create_mem_ref (gimple_stmt_iterator
*gsi
, tree type
, aff_tree
*addr
,
582 struct mem_address parts
;
584 addr_to_parts (addr
, &parts
, speed
);
585 gimplify_mem_ref_parts (gsi
, &parts
);
586 mem_ref
= create_mem_ref_raw (type
, &parts
);
590 /* The expression is too complicated. Try making it simpler. */
592 if (parts
.step
&& !integer_onep (parts
.step
))
594 /* Move the multiplication to index. */
595 gcc_assert (parts
.index
);
596 parts
.index
= force_gimple_operand_gsi (gsi
,
597 fold_build2 (MULT_EXPR
, sizetype
,
598 parts
.index
, parts
.step
),
599 true, NULL_TREE
, true, GSI_SAME_STMT
);
600 parts
.step
= NULL_TREE
;
602 mem_ref
= create_mem_ref_raw (type
, &parts
);
609 tmp
= build_addr (parts
.symbol
, current_function_decl
);
610 gcc_assert (is_gimple_val (tmp
));
612 /* Add the symbol to base, eventually forcing it to register. */
615 gcc_assert (useless_type_conversion_p
616 (sizetype
, TREE_TYPE (parts
.base
)));
620 atype
= TREE_TYPE (tmp
);
621 parts
.base
= force_gimple_operand_gsi (gsi
,
622 fold_build2 (POINTER_PLUS_EXPR
, atype
,
624 fold_convert (sizetype
, parts
.base
)),
625 true, NULL_TREE
, true, GSI_SAME_STMT
);
629 parts
.index
= parts
.base
;
635 parts
.symbol
= NULL_TREE
;
637 mem_ref
= create_mem_ref_raw (type
, &parts
);
644 /* Add index to base. */
647 atype
= TREE_TYPE (parts
.base
);
648 parts
.base
= force_gimple_operand_gsi (gsi
,
649 fold_build2 (POINTER_PLUS_EXPR
, atype
,
652 true, NULL_TREE
, true, GSI_SAME_STMT
);
655 parts
.base
= parts
.index
;
656 parts
.index
= NULL_TREE
;
658 mem_ref
= create_mem_ref_raw (type
, &parts
);
663 if (parts
.offset
&& !integer_zerop (parts
.offset
))
665 /* Try adding offset to base. */
668 atype
= TREE_TYPE (parts
.base
);
669 parts
.base
= force_gimple_operand_gsi (gsi
,
670 fold_build2 (POINTER_PLUS_EXPR
, atype
,
672 fold_convert (sizetype
, parts
.offset
)),
673 true, NULL_TREE
, true, GSI_SAME_STMT
);
676 parts
.base
= parts
.offset
;
678 parts
.offset
= NULL_TREE
;
680 mem_ref
= create_mem_ref_raw (type
, &parts
);
685 /* Verify that the address is in the simplest possible shape
686 (only a register). If we cannot create such a memory reference,
687 something is really wrong. */
688 gcc_assert (parts
.symbol
== NULL_TREE
);
689 gcc_assert (parts
.index
== NULL_TREE
);
690 gcc_assert (!parts
.step
|| integer_onep (parts
.step
));
691 gcc_assert (!parts
.offset
|| integer_zerop (parts
.offset
));
695 /* Copies components of the address from OP to ADDR. */
698 get_address_description (tree op
, struct mem_address
*addr
)
700 addr
->symbol
= TMR_SYMBOL (op
);
701 addr
->base
= TMR_BASE (op
);
702 addr
->index
= TMR_INDEX (op
);
703 addr
->step
= TMR_STEP (op
);
704 addr
->offset
= TMR_OFFSET (op
);
707 /* Copies the additional information attached to target_mem_ref FROM to TO. */
710 copy_mem_ref_info (tree to
, tree from
)
712 /* And the info about the original reference. */
713 TMR_ORIGINAL (to
) = TMR_ORIGINAL (from
);
716 /* Move constants in target_mem_ref REF to offset. Returns the new target
717 mem ref if anything changes, NULL_TREE otherwise. */
720 maybe_fold_tmr (tree ref
)
722 struct mem_address addr
;
723 bool changed
= false;
726 get_address_description (ref
, &addr
);
728 if (addr
.base
&& TREE_CODE (addr
.base
) == INTEGER_CST
)
731 addr
.offset
= fold_binary_to_constant (PLUS_EXPR
, sizetype
,
733 fold_convert (sizetype
, addr
.base
));
735 addr
.offset
= addr
.base
;
737 addr
.base
= NULL_TREE
;
741 if (addr
.index
&& TREE_CODE (addr
.index
) == INTEGER_CST
)
746 off
= fold_binary_to_constant (MULT_EXPR
, sizetype
,
748 addr
.step
= NULL_TREE
;
753 addr
.offset
= fold_binary_to_constant (PLUS_EXPR
, sizetype
,
759 addr
.index
= NULL_TREE
;
766 ret
= create_mem_ref_raw (TREE_TYPE (ref
), &addr
);
770 copy_mem_ref_info (ret
, ref
);
774 /* Dump PARTS to FILE. */
776 extern void dump_mem_address (FILE *, struct mem_address
*);
778 dump_mem_address (FILE *file
, struct mem_address
*parts
)
782 fprintf (file
, "symbol: ");
783 print_generic_expr (file
, parts
->symbol
, TDF_SLIM
);
784 fprintf (file
, "\n");
788 fprintf (file
, "base: ");
789 print_generic_expr (file
, parts
->base
, TDF_SLIM
);
790 fprintf (file
, "\n");
794 fprintf (file
, "index: ");
795 print_generic_expr (file
, parts
->index
, TDF_SLIM
);
796 fprintf (file
, "\n");
800 fprintf (file
, "step: ");
801 print_generic_expr (file
, parts
->step
, TDF_SLIM
);
802 fprintf (file
, "\n");
806 fprintf (file
, "offset: ");
807 print_generic_expr (file
, parts
->offset
, TDF_SLIM
);
808 fprintf (file
, "\n");
812 #include "gt-tree-ssa-address.h"