Fix ChangeLog record for 171649:
[official-gcc.git] / gcc / ira.c
blob41a2928d0c9dab8ead0380f4a401845846f0e664
1 /* Integrated Register Allocator (IRA) entry point.
2 Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012
3 Free Software Foundation, Inc.
4 Contributed by Vladimir Makarov <vmakarov@redhat.com>.
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
11 version.
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
16 for more details.
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/>. */
22 /* The integrated register allocator (IRA) is a
23 regional register allocator performing graph coloring on a top-down
24 traversal of nested regions. Graph coloring in a region is based
25 on Chaitin-Briggs algorithm. It is called integrated because
26 register coalescing, register live range splitting, and choosing a
27 better hard register are done on-the-fly during coloring. Register
28 coalescing and choosing a cheaper hard register is done by hard
29 register preferencing during hard register assigning. The live
30 range splitting is a byproduct of the regional register allocation.
32 Major IRA notions are:
34 o *Region* is a part of CFG where graph coloring based on
35 Chaitin-Briggs algorithm is done. IRA can work on any set of
36 nested CFG regions forming a tree. Currently the regions are
37 the entire function for the root region and natural loops for
38 the other regions. Therefore data structure representing a
39 region is called loop_tree_node.
41 o *Allocno class* is a register class used for allocation of
42 given allocno. It means that only hard register of given
43 register class can be assigned to given allocno. In reality,
44 even smaller subset of (*profitable*) hard registers can be
45 assigned. In rare cases, the subset can be even smaller
46 because our modification of Chaitin-Briggs algorithm requires
47 that sets of hard registers can be assigned to allocnos forms a
48 forest, i.e. the sets can be ordered in a way where any
49 previous set is not intersected with given set or is a superset
50 of given set.
52 o *Pressure class* is a register class belonging to a set of
53 register classes containing all of the hard-registers available
54 for register allocation. The set of all pressure classes for a
55 target is defined in the corresponding machine-description file
56 according some criteria. Register pressure is calculated only
57 for pressure classes and it affects some IRA decisions as
58 forming allocation regions.
60 o *Allocno* represents the live range of a pseudo-register in a
61 region. Besides the obvious attributes like the corresponding
62 pseudo-register number, allocno class, conflicting allocnos and
63 conflicting hard-registers, there are a few allocno attributes
64 which are important for understanding the allocation algorithm:
66 - *Live ranges*. This is a list of ranges of *program points*
67 where the allocno lives. Program points represent places
68 where a pseudo can be born or become dead (there are
69 approximately two times more program points than the insns)
70 and they are represented by integers starting with 0. The
71 live ranges are used to find conflicts between allocnos.
72 They also play very important role for the transformation of
73 the IRA internal representation of several regions into a one
74 region representation. The later is used during the reload
75 pass work because each allocno represents all of the
76 corresponding pseudo-registers.
78 - *Hard-register costs*. This is a vector of size equal to the
79 number of available hard-registers of the allocno class. The
80 cost of a callee-clobbered hard-register for an allocno is
81 increased by the cost of save/restore code around the calls
82 through the given allocno's life. If the allocno is a move
83 instruction operand and another operand is a hard-register of
84 the allocno class, the cost of the hard-register is decreased
85 by the move cost.
87 When an allocno is assigned, the hard-register with minimal
88 full cost is used. Initially, a hard-register's full cost is
89 the corresponding value from the hard-register's cost vector.
90 If the allocno is connected by a *copy* (see below) to
91 another allocno which has just received a hard-register, the
92 cost of the hard-register is decreased. Before choosing a
93 hard-register for an allocno, the allocno's current costs of
94 the hard-registers are modified by the conflict hard-register
95 costs of all of the conflicting allocnos which are not
96 assigned yet.
98 - *Conflict hard-register costs*. This is a vector of the same
99 size as the hard-register costs vector. To permit an
100 unassigned allocno to get a better hard-register, IRA uses
101 this vector to calculate the final full cost of the
102 available hard-registers. Conflict hard-register costs of an
103 unassigned allocno are also changed with a change of the
104 hard-register cost of the allocno when a copy involving the
105 allocno is processed as described above. This is done to
106 show other unassigned allocnos that a given allocno prefers
107 some hard-registers in order to remove the move instruction
108 corresponding to the copy.
110 o *Cap*. If a pseudo-register does not live in a region but
111 lives in a nested region, IRA creates a special allocno called
112 a cap in the outer region. A region cap is also created for a
113 subregion cap.
115 o *Copy*. Allocnos can be connected by copies. Copies are used
116 to modify hard-register costs for allocnos during coloring.
117 Such modifications reflects a preference to use the same
118 hard-register for the allocnos connected by copies. Usually
119 copies are created for move insns (in this case it results in
120 register coalescing). But IRA also creates copies for operands
121 of an insn which should be assigned to the same hard-register
122 due to constraints in the machine description (it usually
123 results in removing a move generated in reload to satisfy
124 the constraints) and copies referring to the allocno which is
125 the output operand of an instruction and the allocno which is
126 an input operand dying in the instruction (creation of such
127 copies results in less register shuffling). IRA *does not*
128 create copies between the same register allocnos from different
129 regions because we use another technique for propagating
130 hard-register preference on the borders of regions.
132 Allocnos (including caps) for the upper region in the region tree
133 *accumulate* information important for coloring from allocnos with
134 the same pseudo-register from nested regions. This includes
135 hard-register and memory costs, conflicts with hard-registers,
136 allocno conflicts, allocno copies and more. *Thus, attributes for
137 allocnos in a region have the same values as if the region had no
138 subregions*. It means that attributes for allocnos in the
139 outermost region corresponding to the function have the same values
140 as though the allocation used only one region which is the entire
141 function. It also means that we can look at IRA work as if the
142 first IRA did allocation for all function then it improved the
143 allocation for loops then their subloops and so on.
145 IRA major passes are:
147 o Building IRA internal representation which consists of the
148 following subpasses:
150 * First, IRA builds regions and creates allocnos (file
151 ira-build.c) and initializes most of their attributes.
153 * Then IRA finds an allocno class for each allocno and
154 calculates its initial (non-accumulated) cost of memory and
155 each hard-register of its allocno class (file ira-cost.c).
157 * IRA creates live ranges of each allocno, calulates register
158 pressure for each pressure class in each region, sets up
159 conflict hard registers for each allocno and info about calls
160 the allocno lives through (file ira-lives.c).
162 * IRA removes low register pressure loops from the regions
163 mostly to speed IRA up (file ira-build.c).
165 * IRA propagates accumulated allocno info from lower region
166 allocnos to corresponding upper region allocnos (file
167 ira-build.c).
169 * IRA creates all caps (file ira-build.c).
171 * Having live-ranges of allocnos and their classes, IRA creates
172 conflicting allocnos for each allocno. Conflicting allocnos
173 are stored as a bit vector or array of pointers to the
174 conflicting allocnos whatever is more profitable (file
175 ira-conflicts.c). At this point IRA creates allocno copies.
177 o Coloring. Now IRA has all necessary info to start graph coloring
178 process. It is done in each region on top-down traverse of the
179 region tree (file ira-color.c). There are following subpasses:
181 * Finding profitable hard registers of corresponding allocno
182 class for each allocno. For example, only callee-saved hard
183 registers are frequently profitable for allocnos living
184 through colors. If the profitable hard register set of
185 allocno does not form a tree based on subset relation, we use
186 some approximation to form the tree. This approximation is
187 used to figure out trivial colorability of allocnos. The
188 approximation is a pretty rare case.
190 * Putting allocnos onto the coloring stack. IRA uses Briggs
191 optimistic coloring which is a major improvement over
192 Chaitin's coloring. Therefore IRA does not spill allocnos at
193 this point. There is some freedom in the order of putting
194 allocnos on the stack which can affect the final result of
195 the allocation. IRA uses some heuristics to improve the
196 order.
198 We also use a modification of Chaitin-Briggs algorithm which
199 works for intersected register classes of allocnos. To
200 figure out trivial colorability of allocnos, the mentioned
201 above tree of hard register sets is used. To get an idea how
202 the algorithm works in i386 example, let us consider an
203 allocno to which any general hard register can be assigned.
204 If the allocno conflicts with eight allocnos to which only
205 EAX register can be assigned, given allocno is still
206 trivially colorable because all conflicting allocnos might be
207 assigned only to EAX and all other general hard registers are
208 still free.
210 To get an idea of the used trivial colorability criterion, it
211 is also useful to read article "Graph-Coloring Register
212 Allocation for Irregular Architectures" by Michael D. Smith
213 and Glen Holloway. Major difference between the article
214 approach and approach used in IRA is that Smith's approach
215 takes register classes only from machine description and IRA
216 calculate register classes from intermediate code too
217 (e.g. an explicit usage of hard registers in RTL code for
218 parameter passing can result in creation of additional
219 register classes which contain or exclude the hard
220 registers). That makes IRA approach useful for improving
221 coloring even for architectures with regular register files
222 and in fact some benchmarking shows the improvement for
223 regular class architectures is even bigger than for irregular
224 ones. Another difference is that Smith's approach chooses
225 intersection of classes of all insn operands in which a given
226 pseudo occurs. IRA can use bigger classes if it is still
227 more profitable than memory usage.
229 * Popping the allocnos from the stack and assigning them hard
230 registers. If IRA can not assign a hard register to an
231 allocno and the allocno is coalesced, IRA undoes the
232 coalescing and puts the uncoalesced allocnos onto the stack in
233 the hope that some such allocnos will get a hard register
234 separately. If IRA fails to assign hard register or memory
235 is more profitable for it, IRA spills the allocno. IRA
236 assigns the allocno the hard-register with minimal full
237 allocation cost which reflects the cost of usage of the
238 hard-register for the allocno and cost of usage of the
239 hard-register for allocnos conflicting with given allocno.
241 * Chaitin-Briggs coloring assigns as many pseudos as possible
242 to hard registers. After coloringh we try to improve
243 allocation with cost point of view. We improve the
244 allocation by spilling some allocnos and assigning the freed
245 hard registers to other allocnos if it decreases the overall
246 allocation cost.
248 * After allono assigning in the region, IRA modifies the hard
249 register and memory costs for the corresponding allocnos in
250 the subregions to reflect the cost of possible loads, stores,
251 or moves on the border of the region and its subregions.
252 When default regional allocation algorithm is used
253 (-fira-algorithm=mixed), IRA just propagates the assignment
254 for allocnos if the register pressure in the region for the
255 corresponding pressure class is less than number of available
256 hard registers for given pressure class.
258 o Spill/restore code moving. When IRA performs an allocation
259 by traversing regions in top-down order, it does not know what
260 happens below in the region tree. Therefore, sometimes IRA
261 misses opportunities to perform a better allocation. A simple
262 optimization tries to improve allocation in a region having
263 subregions and containing in another region. If the
264 corresponding allocnos in the subregion are spilled, it spills
265 the region allocno if it is profitable. The optimization
266 implements a simple iterative algorithm performing profitable
267 transformations while they are still possible. It is fast in
268 practice, so there is no real need for a better time complexity
269 algorithm.
271 o Code change. After coloring, two allocnos representing the
272 same pseudo-register outside and inside a region respectively
273 may be assigned to different locations (hard-registers or
274 memory). In this case IRA creates and uses a new
275 pseudo-register inside the region and adds code to move allocno
276 values on the region's borders. This is done during top-down
277 traversal of the regions (file ira-emit.c). In some
278 complicated cases IRA can create a new allocno to move allocno
279 values (e.g. when a swap of values stored in two hard-registers
280 is needed). At this stage, the new allocno is marked as
281 spilled. IRA still creates the pseudo-register and the moves
282 on the region borders even when both allocnos were assigned to
283 the same hard-register. If the reload pass spills a
284 pseudo-register for some reason, the effect will be smaller
285 because another allocno will still be in the hard-register. In
286 most cases, this is better then spilling both allocnos. If
287 reload does not change the allocation for the two
288 pseudo-registers, the trivial move will be removed by
289 post-reload optimizations. IRA does not generate moves for
290 allocnos assigned to the same hard register when the default
291 regional allocation algorithm is used and the register pressure
292 in the region for the corresponding pressure class is less than
293 number of available hard registers for given pressure class.
294 IRA also does some optimizations to remove redundant stores and
295 to reduce code duplication on the region borders.
297 o Flattening internal representation. After changing code, IRA
298 transforms its internal representation for several regions into
299 one region representation (file ira-build.c). This process is
300 called IR flattening. Such process is more complicated than IR
301 rebuilding would be, but is much faster.
303 o After IR flattening, IRA tries to assign hard registers to all
304 spilled allocnos. This is impelemented by a simple and fast
305 priority coloring algorithm (see function
306 ira_reassign_conflict_allocnos::ira-color.c). Here new allocnos
307 created during the code change pass can be assigned to hard
308 registers.
310 o At the end IRA calls the reload pass. The reload pass
311 communicates with IRA through several functions in file
312 ira-color.c to improve its decisions in
314 * sharing stack slots for the spilled pseudos based on IRA info
315 about pseudo-register conflicts.
317 * reassigning hard-registers to all spilled pseudos at the end
318 of each reload iteration.
320 * choosing a better hard-register to spill based on IRA info
321 about pseudo-register live ranges and the register pressure
322 in places where the pseudo-register lives.
324 IRA uses a lot of data representing the target processors. These
325 data are initilized in file ira.c.
327 If function has no loops (or the loops are ignored when
328 -fira-algorithm=CB is used), we have classic Chaitin-Briggs
329 coloring (only instead of separate pass of coalescing, we use hard
330 register preferencing). In such case, IRA works much faster
331 because many things are not made (like IR flattening, the
332 spill/restore optimization, and the code change).
334 Literature is worth to read for better understanding the code:
336 o Preston Briggs, Keith D. Cooper, Linda Torczon. Improvements to
337 Graph Coloring Register Allocation.
339 o David Callahan, Brian Koblenz. Register allocation via
340 hierarchical graph coloring.
342 o Keith Cooper, Anshuman Dasgupta, Jason Eckhardt. Revisiting Graph
343 Coloring Register Allocation: A Study of the Chaitin-Briggs and
344 Callahan-Koblenz Algorithms.
346 o Guei-Yuan Lueh, Thomas Gross, and Ali-Reza Adl-Tabatabai. Global
347 Register Allocation Based on Graph Fusion.
349 o Michael D. Smith and Glenn Holloway. Graph-Coloring Register
350 Allocation for Irregular Architectures
352 o Vladimir Makarov. The Integrated Register Allocator for GCC.
354 o Vladimir Makarov. The top-down register allocator for irregular
355 register file architectures.
360 #include "config.h"
361 #include "system.h"
362 #include "coretypes.h"
363 #include "tm.h"
364 #include "regs.h"
365 #include "rtl.h"
366 #include "tm_p.h"
367 #include "target.h"
368 #include "flags.h"
369 #include "obstack.h"
370 #include "bitmap.h"
371 #include "hard-reg-set.h"
372 #include "basic-block.h"
373 #include "df.h"
374 #include "expr.h"
375 #include "recog.h"
376 #include "params.h"
377 #include "timevar.h"
378 #include "tree-pass.h"
379 #include "output.h"
380 #include "except.h"
381 #include "reload.h"
382 #include "diagnostic-core.h"
383 #include "integrate.h"
384 #include "ggc.h"
385 #include "ira-int.h"
386 #include "dce.h"
389 struct target_ira default_target_ira;
390 struct target_ira_int default_target_ira_int;
391 #if SWITCHABLE_TARGET
392 struct target_ira *this_target_ira = &default_target_ira;
393 struct target_ira_int *this_target_ira_int = &default_target_ira_int;
394 #endif
396 /* A modified value of flag `-fira-verbose' used internally. */
397 int internal_flag_ira_verbose;
399 /* Dump file of the allocator if it is not NULL. */
400 FILE *ira_dump_file;
402 /* The number of elements in the following array. */
403 int ira_spilled_reg_stack_slots_num;
405 /* The following array contains info about spilled pseudo-registers
406 stack slots used in current function so far. */
407 struct ira_spilled_reg_stack_slot *ira_spilled_reg_stack_slots;
409 /* Correspondingly overall cost of the allocation, overall cost before
410 reload, cost of the allocnos assigned to hard-registers, cost of
411 the allocnos assigned to memory, cost of loads, stores and register
412 move insns generated for pseudo-register live range splitting (see
413 ira-emit.c). */
414 int ira_overall_cost, overall_cost_before;
415 int ira_reg_cost, ira_mem_cost;
416 int ira_load_cost, ira_store_cost, ira_shuffle_cost;
417 int ira_move_loops_num, ira_additional_jumps_num;
419 /* All registers that can be eliminated. */
421 HARD_REG_SET eliminable_regset;
423 /* Temporary hard reg set used for a different calculation. */
424 static HARD_REG_SET temp_hard_regset;
428 /* The function sets up the map IRA_REG_MODE_HARD_REGSET. */
429 static void
430 setup_reg_mode_hard_regset (void)
432 int i, m, hard_regno;
434 for (m = 0; m < NUM_MACHINE_MODES; m++)
435 for (hard_regno = 0; hard_regno < FIRST_PSEUDO_REGISTER; hard_regno++)
437 CLEAR_HARD_REG_SET (ira_reg_mode_hard_regset[hard_regno][m]);
438 for (i = hard_regno_nregs[hard_regno][m] - 1; i >= 0; i--)
439 if (hard_regno + i < FIRST_PSEUDO_REGISTER)
440 SET_HARD_REG_BIT (ira_reg_mode_hard_regset[hard_regno][m],
441 hard_regno + i);
446 #define no_unit_alloc_regs \
447 (this_target_ira_int->x_no_unit_alloc_regs)
449 /* The function sets up the three arrays declared above. */
450 static void
451 setup_class_hard_regs (void)
453 int cl, i, hard_regno, n;
454 HARD_REG_SET processed_hard_reg_set;
456 ira_assert (SHRT_MAX >= FIRST_PSEUDO_REGISTER);
457 for (cl = (int) N_REG_CLASSES - 1; cl >= 0; cl--)
459 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
460 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
461 CLEAR_HARD_REG_SET (processed_hard_reg_set);
462 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
464 ira_non_ordered_class_hard_regs[cl][i] = -1;
465 ira_class_hard_reg_index[cl][i] = -1;
467 for (n = 0, i = 0; i < FIRST_PSEUDO_REGISTER; i++)
469 #ifdef REG_ALLOC_ORDER
470 hard_regno = reg_alloc_order[i];
471 #else
472 hard_regno = i;
473 #endif
474 if (TEST_HARD_REG_BIT (processed_hard_reg_set, hard_regno))
475 continue;
476 SET_HARD_REG_BIT (processed_hard_reg_set, hard_regno);
477 if (! TEST_HARD_REG_BIT (temp_hard_regset, hard_regno))
478 ira_class_hard_reg_index[cl][hard_regno] = -1;
479 else
481 ira_class_hard_reg_index[cl][hard_regno] = n;
482 ira_class_hard_regs[cl][n++] = hard_regno;
485 ira_class_hard_regs_num[cl] = n;
486 for (n = 0, i = 0; i < FIRST_PSEUDO_REGISTER; i++)
487 if (TEST_HARD_REG_BIT (temp_hard_regset, i))
488 ira_non_ordered_class_hard_regs[cl][n++] = i;
489 ira_assert (ira_class_hard_regs_num[cl] == n);
493 /* Set up IRA_AVAILABLE_CLASS_REGS. */
494 static void
495 setup_available_class_regs (void)
497 int i, j;
499 memset (ira_available_class_regs, 0, sizeof (ira_available_class_regs));
500 for (i = 0; i < N_REG_CLASSES; i++)
502 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[i]);
503 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
504 for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
505 if (TEST_HARD_REG_BIT (temp_hard_regset, j))
506 ira_available_class_regs[i]++;
510 /* Set up global variables defining info about hard registers for the
511 allocation. These depend on USE_HARD_FRAME_P whose TRUE value means
512 that we can use the hard frame pointer for the allocation. */
513 static void
514 setup_alloc_regs (bool use_hard_frame_p)
516 #ifdef ADJUST_REG_ALLOC_ORDER
517 ADJUST_REG_ALLOC_ORDER;
518 #endif
519 COPY_HARD_REG_SET (no_unit_alloc_regs, fixed_reg_set);
520 if (! use_hard_frame_p)
521 SET_HARD_REG_BIT (no_unit_alloc_regs, HARD_FRAME_POINTER_REGNUM);
522 setup_class_hard_regs ();
523 setup_available_class_regs ();
528 #define alloc_reg_class_subclasses \
529 (this_target_ira_int->x_alloc_reg_class_subclasses)
531 /* Initialize the table of subclasses of each reg class. */
532 static void
533 setup_reg_subclasses (void)
535 int i, j;
536 HARD_REG_SET temp_hard_regset2;
538 for (i = 0; i < N_REG_CLASSES; i++)
539 for (j = 0; j < N_REG_CLASSES; j++)
540 alloc_reg_class_subclasses[i][j] = LIM_REG_CLASSES;
542 for (i = 0; i < N_REG_CLASSES; i++)
544 if (i == (int) NO_REGS)
545 continue;
547 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[i]);
548 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
549 if (hard_reg_set_empty_p (temp_hard_regset))
550 continue;
551 for (j = 0; j < N_REG_CLASSES; j++)
552 if (i != j)
554 enum reg_class *p;
556 COPY_HARD_REG_SET (temp_hard_regset2, reg_class_contents[j]);
557 AND_COMPL_HARD_REG_SET (temp_hard_regset2, no_unit_alloc_regs);
558 if (! hard_reg_set_subset_p (temp_hard_regset,
559 temp_hard_regset2))
560 continue;
561 p = &alloc_reg_class_subclasses[j][0];
562 while (*p != LIM_REG_CLASSES) p++;
563 *p = (enum reg_class) i;
570 /* Set up IRA_MEMORY_MOVE_COST and IRA_MAX_MEMORY_MOVE_COST. */
571 static void
572 setup_class_subset_and_memory_move_costs (void)
574 int cl, cl2, mode, cost;
575 HARD_REG_SET temp_hard_regset2;
577 for (mode = 0; mode < MAX_MACHINE_MODE; mode++)
578 ira_memory_move_cost[mode][NO_REGS][0]
579 = ira_memory_move_cost[mode][NO_REGS][1] = SHRT_MAX;
580 for (cl = (int) N_REG_CLASSES - 1; cl >= 0; cl--)
582 if (cl != (int) NO_REGS)
583 for (mode = 0; mode < MAX_MACHINE_MODE; mode++)
585 ira_max_memory_move_cost[mode][cl][0]
586 = ira_memory_move_cost[mode][cl][0]
587 = memory_move_cost ((enum machine_mode) mode,
588 (reg_class_t) cl, false);
589 ira_max_memory_move_cost[mode][cl][1]
590 = ira_memory_move_cost[mode][cl][1]
591 = memory_move_cost ((enum machine_mode) mode,
592 (reg_class_t) cl, true);
593 /* Costs for NO_REGS are used in cost calculation on the
594 1st pass when the preferred register classes are not
595 known yet. In this case we take the best scenario. */
596 if (ira_memory_move_cost[mode][NO_REGS][0]
597 > ira_memory_move_cost[mode][cl][0])
598 ira_max_memory_move_cost[mode][NO_REGS][0]
599 = ira_memory_move_cost[mode][NO_REGS][0]
600 = ira_memory_move_cost[mode][cl][0];
601 if (ira_memory_move_cost[mode][NO_REGS][1]
602 > ira_memory_move_cost[mode][cl][1])
603 ira_max_memory_move_cost[mode][NO_REGS][1]
604 = ira_memory_move_cost[mode][NO_REGS][1]
605 = ira_memory_move_cost[mode][cl][1];
608 for (cl = (int) N_REG_CLASSES - 1; cl >= 0; cl--)
609 for (cl2 = (int) N_REG_CLASSES - 1; cl2 >= 0; cl2--)
611 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
612 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
613 COPY_HARD_REG_SET (temp_hard_regset2, reg_class_contents[cl2]);
614 AND_COMPL_HARD_REG_SET (temp_hard_regset2, no_unit_alloc_regs);
615 ira_class_subset_p[cl][cl2]
616 = hard_reg_set_subset_p (temp_hard_regset, temp_hard_regset2);
617 if (! hard_reg_set_empty_p (temp_hard_regset2)
618 && hard_reg_set_subset_p (reg_class_contents[cl2],
619 reg_class_contents[cl]))
620 for (mode = 0; mode < MAX_MACHINE_MODE; mode++)
622 cost = ira_memory_move_cost[mode][cl2][0];
623 if (cost > ira_max_memory_move_cost[mode][cl][0])
624 ira_max_memory_move_cost[mode][cl][0] = cost;
625 cost = ira_memory_move_cost[mode][cl2][1];
626 if (cost > ira_max_memory_move_cost[mode][cl][1])
627 ira_max_memory_move_cost[mode][cl][1] = cost;
630 for (cl = (int) N_REG_CLASSES - 1; cl >= 0; cl--)
631 for (mode = 0; mode < MAX_MACHINE_MODE; mode++)
633 ira_memory_move_cost[mode][cl][0]
634 = ira_max_memory_move_cost[mode][cl][0];
635 ira_memory_move_cost[mode][cl][1]
636 = ira_max_memory_move_cost[mode][cl][1];
638 setup_reg_subclasses ();
643 /* Define the following macro if allocation through malloc if
644 preferable. */
645 #define IRA_NO_OBSTACK
647 #ifndef IRA_NO_OBSTACK
648 /* Obstack used for storing all dynamic data (except bitmaps) of the
649 IRA. */
650 static struct obstack ira_obstack;
651 #endif
653 /* Obstack used for storing all bitmaps of the IRA. */
654 static struct bitmap_obstack ira_bitmap_obstack;
656 /* Allocate memory of size LEN for IRA data. */
657 void *
658 ira_allocate (size_t len)
660 void *res;
662 #ifndef IRA_NO_OBSTACK
663 res = obstack_alloc (&ira_obstack, len);
664 #else
665 res = xmalloc (len);
666 #endif
667 return res;
670 /* Free memory ADDR allocated for IRA data. */
671 void
672 ira_free (void *addr ATTRIBUTE_UNUSED)
674 #ifndef IRA_NO_OBSTACK
675 /* do nothing */
676 #else
677 free (addr);
678 #endif
682 /* Allocate and returns bitmap for IRA. */
683 bitmap
684 ira_allocate_bitmap (void)
686 return BITMAP_ALLOC (&ira_bitmap_obstack);
689 /* Free bitmap B allocated for IRA. */
690 void
691 ira_free_bitmap (bitmap b ATTRIBUTE_UNUSED)
693 /* do nothing */
698 /* Output information about allocation of all allocnos (except for
699 caps) into file F. */
700 void
701 ira_print_disposition (FILE *f)
703 int i, n, max_regno;
704 ira_allocno_t a;
705 basic_block bb;
707 fprintf (f, "Disposition:");
708 max_regno = max_reg_num ();
709 for (n = 0, i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
710 for (a = ira_regno_allocno_map[i];
711 a != NULL;
712 a = ALLOCNO_NEXT_REGNO_ALLOCNO (a))
714 if (n % 4 == 0)
715 fprintf (f, "\n");
716 n++;
717 fprintf (f, " %4d:r%-4d", ALLOCNO_NUM (a), ALLOCNO_REGNO (a));
718 if ((bb = ALLOCNO_LOOP_TREE_NODE (a)->bb) != NULL)
719 fprintf (f, "b%-3d", bb->index);
720 else
721 fprintf (f, "l%-3d", ALLOCNO_LOOP_TREE_NODE (a)->loop_num);
722 if (ALLOCNO_HARD_REGNO (a) >= 0)
723 fprintf (f, " %3d", ALLOCNO_HARD_REGNO (a));
724 else
725 fprintf (f, " mem");
727 fprintf (f, "\n");
730 /* Outputs information about allocation of all allocnos into
731 stderr. */
732 void
733 ira_debug_disposition (void)
735 ira_print_disposition (stderr);
740 /* Set up ira_stack_reg_pressure_class which is the biggest pressure
741 register class containing stack registers or NO_REGS if there are
742 no stack registers. To find this class, we iterate through all
743 register pressure classes and choose the first register pressure
744 class containing all the stack registers and having the biggest
745 size. */
746 static void
747 setup_stack_reg_pressure_class (void)
749 ira_stack_reg_pressure_class = NO_REGS;
750 #ifdef STACK_REGS
752 int i, best, size;
753 enum reg_class cl;
754 HARD_REG_SET temp_hard_regset2;
756 CLEAR_HARD_REG_SET (temp_hard_regset);
757 for (i = FIRST_STACK_REG; i <= LAST_STACK_REG; i++)
758 SET_HARD_REG_BIT (temp_hard_regset, i);
759 best = 0;
760 for (i = 0; i < ira_pressure_classes_num; i++)
762 cl = ira_pressure_classes[i];
763 COPY_HARD_REG_SET (temp_hard_regset2, temp_hard_regset);
764 AND_HARD_REG_SET (temp_hard_regset2, reg_class_contents[cl]);
765 size = hard_reg_set_size (temp_hard_regset2);
766 if (best < size)
768 best = size;
769 ira_stack_reg_pressure_class = cl;
773 #endif
776 /* Find pressure classes which are register classes for which we
777 calculate register pressure in IRA, register pressure sensitive
778 insn scheduling, and register pressure sensitive loop invariant
779 motion.
781 To make register pressure calculation easy, we always use
782 non-intersected register pressure classes. A move of hard
783 registers from one register pressure class is not more expensive
784 than load and store of the hard registers. Most likely an allocno
785 class will be a subset of a register pressure class and in many
786 cases a register pressure class. That makes usage of register
787 pressure classes a good approximation to find a high register
788 pressure. */
789 static void
790 setup_pressure_classes (void)
792 int cost, i, n, curr;
793 int cl, cl2;
794 enum reg_class pressure_classes[N_REG_CLASSES];
795 int m;
796 HARD_REG_SET temp_hard_regset2;
797 bool insert_p;
799 n = 0;
800 for (cl = 0; cl < N_REG_CLASSES; cl++)
802 if (ira_available_class_regs[cl] == 0)
803 continue;
804 if (ira_available_class_regs[cl] != 1
805 /* A register class without subclasses may contain a few
806 hard registers and movement between them is costly
807 (e.g. SPARC FPCC registers). We still should consider it
808 as a candidate for a pressure class. */
809 && alloc_reg_class_subclasses[cl][0] != LIM_REG_CLASSES)
811 /* Check that the moves between any hard registers of the
812 current class are not more expensive for a legal mode
813 than load/store of the hard registers of the current
814 class. Such class is a potential candidate to be a
815 register pressure class. */
816 for (m = 0; m < NUM_MACHINE_MODES; m++)
818 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
819 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
820 AND_COMPL_HARD_REG_SET (temp_hard_regset,
821 ira_prohibited_class_mode_regs[cl][m]);
822 if (hard_reg_set_empty_p (temp_hard_regset))
823 continue;
824 ira_init_register_move_cost_if_necessary ((enum machine_mode) m);
825 cost = ira_register_move_cost[m][cl][cl];
826 if (cost <= ira_max_memory_move_cost[m][cl][1]
827 || cost <= ira_max_memory_move_cost[m][cl][0])
828 break;
830 if (m >= NUM_MACHINE_MODES)
831 continue;
833 curr = 0;
834 insert_p = true;
835 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
836 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
837 /* Remove so far added pressure classes which are subset of the
838 current candidate class. Prefer GENERAL_REGS as a pressure
839 register class to another class containing the same
840 allocatable hard registers. We do this because machine
841 dependent cost hooks might give wrong costs for the latter
842 class but always give the right cost for the former class
843 (GENERAL_REGS). */
844 for (i = 0; i < n; i++)
846 cl2 = pressure_classes[i];
847 COPY_HARD_REG_SET (temp_hard_regset2, reg_class_contents[cl2]);
848 AND_COMPL_HARD_REG_SET (temp_hard_regset2, no_unit_alloc_regs);
849 if (hard_reg_set_subset_p (temp_hard_regset, temp_hard_regset2)
850 && (! hard_reg_set_equal_p (temp_hard_regset, temp_hard_regset2)
851 || cl2 == (int) GENERAL_REGS))
853 pressure_classes[curr++] = (enum reg_class) cl2;
854 insert_p = false;
855 continue;
857 if (hard_reg_set_subset_p (temp_hard_regset2, temp_hard_regset)
858 && (! hard_reg_set_equal_p (temp_hard_regset2, temp_hard_regset)
859 || cl == (int) GENERAL_REGS))
860 continue;
861 if (hard_reg_set_equal_p (temp_hard_regset2, temp_hard_regset))
862 insert_p = false;
863 pressure_classes[curr++] = (enum reg_class) cl2;
865 /* If the current candidate is a subset of a so far added
866 pressure class, don't add it to the list of the pressure
867 classes. */
868 if (insert_p)
869 pressure_classes[curr++] = (enum reg_class) cl;
870 n = curr;
872 #ifdef ENABLE_IRA_CHECKING
874 HARD_REG_SET ignore_hard_regs;
876 /* Check pressure classes correctness: here we check that hard
877 registers from all register pressure classes contains all hard
878 registers available for the allocation. */
879 CLEAR_HARD_REG_SET (temp_hard_regset);
880 CLEAR_HARD_REG_SET (temp_hard_regset2);
881 COPY_HARD_REG_SET (ignore_hard_regs, no_unit_alloc_regs);
882 for (cl = 0; cl < LIM_REG_CLASSES; cl++)
884 /* For some targets (like MIPS with MD_REGS), there are some
885 classes with hard registers available for allocation but
886 not able to hold value of any mode. */
887 for (m = 0; m < NUM_MACHINE_MODES; m++)
888 if (contains_reg_of_mode[cl][m])
889 break;
890 if (m >= NUM_MACHINE_MODES)
892 IOR_HARD_REG_SET (ignore_hard_regs, reg_class_contents[cl]);
893 continue;
895 for (i = 0; i < n; i++)
896 if ((int) pressure_classes[i] == cl)
897 break;
898 IOR_HARD_REG_SET (temp_hard_regset2, reg_class_contents[cl]);
899 if (i < n)
900 IOR_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
902 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
903 /* Some targets (like SPARC with ICC reg) have alocatable regs
904 for which no reg class is defined. */
905 if (REGNO_REG_CLASS (i) == NO_REGS)
906 SET_HARD_REG_BIT (ignore_hard_regs, i);
907 AND_COMPL_HARD_REG_SET (temp_hard_regset, ignore_hard_regs);
908 AND_COMPL_HARD_REG_SET (temp_hard_regset2, ignore_hard_regs);
909 ira_assert (hard_reg_set_subset_p (temp_hard_regset2, temp_hard_regset));
911 #endif
912 ira_pressure_classes_num = 0;
913 for (i = 0; i < n; i++)
915 cl = (int) pressure_classes[i];
916 ira_reg_pressure_class_p[cl] = true;
917 ira_pressure_classes[ira_pressure_classes_num++] = (enum reg_class) cl;
919 setup_stack_reg_pressure_class ();
922 /* Set up IRA_ALLOCNO_CLASSES, IRA_ALLOCNO_CLASSES_NUM,
923 IRA_IMPORTANT_CLASSES, and IRA_IMPORTANT_CLASSES_NUM.
925 Target may have many subtargets and not all target hard regiters can
926 be used for allocation, e.g. x86 port in 32-bit mode can not use
927 hard registers introduced in x86-64 like r8-r15). Some classes
928 might have the same allocatable hard registers, e.g. INDEX_REGS
929 and GENERAL_REGS in x86 port in 32-bit mode. To decrease different
930 calculations efforts we introduce allocno classes which contain
931 unique non-empty sets of allocatable hard-registers.
933 Pseudo class cost calculation in ira-costs.c is very expensive.
934 Therefore we are trying to decrease number of classes involved in
935 such calculation. Register classes used in the cost calculation
936 are called important classes. They are allocno classes and other
937 non-empty classes whose allocatable hard register sets are inside
938 of an allocno class hard register set. From the first sight, it
939 looks like that they are just allocno classes. It is not true. In
940 example of x86-port in 32-bit mode, allocno classes will contain
941 GENERAL_REGS but not LEGACY_REGS (because allocatable hard
942 registers are the same for the both classes). The important
943 classes will contain GENERAL_REGS and LEGACY_REGS. It is done
944 because a machine description insn constraint may refers for
945 LEGACY_REGS and code in ira-costs.c is mostly base on investigation
946 of the insn constraints. */
947 static void
948 setup_allocno_and_important_classes (void)
950 int i, j, n, cl;
951 bool set_p;
952 HARD_REG_SET temp_hard_regset2;
953 static enum reg_class classes[LIM_REG_CLASSES + 1];
955 n = 0;
956 /* Collect classes which contain unique sets of allocatable hard
957 registers. Prefer GENERAL_REGS to other classes containing the
958 same set of hard registers. */
959 for (i = 0; i < LIM_REG_CLASSES; i++)
961 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[i]);
962 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
963 for (j = 0; j < n; j++)
965 cl = classes[j];
966 COPY_HARD_REG_SET (temp_hard_regset2, reg_class_contents[cl]);
967 AND_COMPL_HARD_REG_SET (temp_hard_regset2,
968 no_unit_alloc_regs);
969 if (hard_reg_set_equal_p (temp_hard_regset,
970 temp_hard_regset2))
971 break;
973 if (j >= n)
974 classes[n++] = (enum reg_class) i;
975 else if (i == GENERAL_REGS)
976 /* Prefer general regs. For i386 example, it means that
977 we prefer GENERAL_REGS over INDEX_REGS or LEGACY_REGS
978 (all of them consists of the same available hard
979 registers). */
980 classes[j] = (enum reg_class) i;
982 classes[n] = LIM_REG_CLASSES;
984 /* Set up classes which can be used for allocnos as classes
985 conatining non-empty unique sets of allocatable hard
986 registers. */
987 ira_allocno_classes_num = 0;
988 for (i = 0; (cl = classes[i]) != LIM_REG_CLASSES; i++)
990 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
991 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
992 if (hard_reg_set_empty_p (temp_hard_regset))
993 continue;
994 ira_allocno_classes[ira_allocno_classes_num++] = (enum reg_class) cl;
996 ira_important_classes_num = 0;
997 /* Add non-allocno classes containing to non-empty set of
998 allocatable hard regs. */
999 for (cl = 0; cl < N_REG_CLASSES; cl++)
1001 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
1002 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
1003 if (! hard_reg_set_empty_p (temp_hard_regset))
1005 set_p = false;
1006 for (j = 0; j < ira_allocno_classes_num; j++)
1008 COPY_HARD_REG_SET (temp_hard_regset2,
1009 reg_class_contents[ira_allocno_classes[j]]);
1010 AND_COMPL_HARD_REG_SET (temp_hard_regset2, no_unit_alloc_regs);
1011 if ((enum reg_class) cl == ira_allocno_classes[j])
1012 break;
1013 else if (hard_reg_set_subset_p (temp_hard_regset,
1014 temp_hard_regset2))
1015 set_p = true;
1017 if (set_p && j >= ira_allocno_classes_num)
1018 ira_important_classes[ira_important_classes_num++]
1019 = (enum reg_class) cl;
1022 /* Now add allocno classes to the important classes. */
1023 for (j = 0; j < ira_allocno_classes_num; j++)
1024 ira_important_classes[ira_important_classes_num++]
1025 = ira_allocno_classes[j];
1026 for (cl = 0; cl < N_REG_CLASSES; cl++)
1028 ira_reg_allocno_class_p[cl] = false;
1029 ira_reg_pressure_class_p[cl] = false;
1031 for (j = 0; j < ira_allocno_classes_num; j++)
1032 ira_reg_allocno_class_p[ira_allocno_classes[j]] = true;
1033 setup_pressure_classes ();
1036 /* Setup translation in CLASS_TRANSLATE of all classes into a class
1037 given by array CLASSES of length CLASSES_NUM. The function is used
1038 make translation any reg class to an allocno class or to an
1039 pressure class. This translation is necessary for some
1040 calculations when we can use only allocno or pressure classes and
1041 such translation represents an approximate representation of all
1042 classes.
1044 The translation in case when allocatable hard register set of a
1045 given class is subset of allocatable hard register set of a class
1046 in CLASSES is pretty simple. We use smallest classes from CLASSES
1047 containing a given class. If allocatable hard register set of a
1048 given class is not a subset of any corresponding set of a class
1049 from CLASSES, we use the cheapest (with load/store point of view)
1050 class from CLASSES whose set intersects with given class set */
1051 static void
1052 setup_class_translate_array (enum reg_class *class_translate,
1053 int classes_num, enum reg_class *classes)
1055 int cl, mode;
1056 enum reg_class aclass, best_class, *cl_ptr;
1057 int i, cost, min_cost, best_cost;
1059 for (cl = 0; cl < N_REG_CLASSES; cl++)
1060 class_translate[cl] = NO_REGS;
1062 for (i = 0; i < classes_num; i++)
1064 aclass = classes[i];
1065 for (cl_ptr = &alloc_reg_class_subclasses[aclass][0];
1066 (cl = *cl_ptr) != LIM_REG_CLASSES;
1067 cl_ptr++)
1068 if (class_translate[cl] == NO_REGS)
1069 class_translate[cl] = aclass;
1070 class_translate[aclass] = aclass;
1072 /* For classes which are not fully covered by one of given classes
1073 (in other words covered by more one given class), use the
1074 cheapest class. */
1075 for (cl = 0; cl < N_REG_CLASSES; cl++)
1077 if (cl == NO_REGS || class_translate[cl] != NO_REGS)
1078 continue;
1079 best_class = NO_REGS;
1080 best_cost = INT_MAX;
1081 for (i = 0; i < classes_num; i++)
1083 aclass = classes[i];
1084 COPY_HARD_REG_SET (temp_hard_regset,
1085 reg_class_contents[aclass]);
1086 AND_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
1087 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
1088 if (! hard_reg_set_empty_p (temp_hard_regset))
1090 min_cost = INT_MAX;
1091 for (mode = 0; mode < MAX_MACHINE_MODE; mode++)
1093 cost = (ira_memory_move_cost[mode][cl][0]
1094 + ira_memory_move_cost[mode][cl][1]);
1095 if (min_cost > cost)
1096 min_cost = cost;
1098 if (best_class == NO_REGS || best_cost > min_cost)
1100 best_class = aclass;
1101 best_cost = min_cost;
1105 class_translate[cl] = best_class;
1109 /* Set up array IRA_ALLOCNO_CLASS_TRANSLATE and
1110 IRA_PRESSURE_CLASS_TRANSLATE. */
1111 static void
1112 setup_class_translate (void)
1114 setup_class_translate_array (ira_allocno_class_translate,
1115 ira_allocno_classes_num, ira_allocno_classes);
1116 setup_class_translate_array (ira_pressure_class_translate,
1117 ira_pressure_classes_num, ira_pressure_classes);
1120 /* Order numbers of allocno classes in original target allocno class
1121 array, -1 for non-allocno classes. */
1122 static int allocno_class_order[N_REG_CLASSES];
1124 /* The function used to sort the important classes. */
1125 static int
1126 comp_reg_classes_func (const void *v1p, const void *v2p)
1128 enum reg_class cl1 = *(const enum reg_class *) v1p;
1129 enum reg_class cl2 = *(const enum reg_class *) v2p;
1130 enum reg_class tcl1, tcl2;
1131 int diff;
1133 tcl1 = ira_allocno_class_translate[cl1];
1134 tcl2 = ira_allocno_class_translate[cl2];
1135 if (tcl1 != NO_REGS && tcl2 != NO_REGS
1136 && (diff = allocno_class_order[tcl1] - allocno_class_order[tcl2]) != 0)
1137 return diff;
1138 return (int) cl1 - (int) cl2;
1141 /* For correct work of function setup_reg_class_relation we need to
1142 reorder important classes according to the order of their allocno
1143 classes. It places important classes containing the same
1144 allocatable hard register set adjacent to each other and allocno
1145 class with the allocatable hard register set right after the other
1146 important classes with the same set.
1148 In example from comments of function
1149 setup_allocno_and_important_classes, it places LEGACY_REGS and
1150 GENERAL_REGS close to each other and GENERAL_REGS is after
1151 LEGACY_REGS. */
1152 static void
1153 reorder_important_classes (void)
1155 int i;
1157 for (i = 0; i < N_REG_CLASSES; i++)
1158 allocno_class_order[i] = -1;
1159 for (i = 0; i < ira_allocno_classes_num; i++)
1160 allocno_class_order[ira_allocno_classes[i]] = i;
1161 qsort (ira_important_classes, ira_important_classes_num,
1162 sizeof (enum reg_class), comp_reg_classes_func);
1163 for (i = 0; i < ira_important_classes_num; i++)
1164 ira_important_class_nums[ira_important_classes[i]] = i;
1167 /* Set up IRA_REG_CLASS_SUBUNION, IRA_REG_CLASS_SUPERUNION,
1168 IRA_REG_CLASS_SUPER_CLASSES, IRA_REG_CLASSES_INTERSECT, and
1169 IRA_REG_CLASSES_INTERSECT_P. For the meaning of the relations,
1170 please see corresponding comments in ira-int.h. */
1171 static void
1172 setup_reg_class_relations (void)
1174 int i, cl1, cl2, cl3;
1175 HARD_REG_SET intersection_set, union_set, temp_set2;
1176 bool important_class_p[N_REG_CLASSES];
1178 memset (important_class_p, 0, sizeof (important_class_p));
1179 for (i = 0; i < ira_important_classes_num; i++)
1180 important_class_p[ira_important_classes[i]] = true;
1181 for (cl1 = 0; cl1 < N_REG_CLASSES; cl1++)
1183 ira_reg_class_super_classes[cl1][0] = LIM_REG_CLASSES;
1184 for (cl2 = 0; cl2 < N_REG_CLASSES; cl2++)
1186 ira_reg_classes_intersect_p[cl1][cl2] = false;
1187 ira_reg_class_intersect[cl1][cl2] = NO_REGS;
1188 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl1]);
1189 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
1190 COPY_HARD_REG_SET (temp_set2, reg_class_contents[cl2]);
1191 AND_COMPL_HARD_REG_SET (temp_set2, no_unit_alloc_regs);
1192 if (hard_reg_set_empty_p (temp_hard_regset)
1193 && hard_reg_set_empty_p (temp_set2))
1195 /* The both classes have no allocatable hard registers
1196 -- take all class hard registers into account and use
1197 reg_class_subunion and reg_class_superunion. */
1198 for (i = 0;; i++)
1200 cl3 = reg_class_subclasses[cl1][i];
1201 if (cl3 == LIM_REG_CLASSES)
1202 break;
1203 if (reg_class_subset_p (ira_reg_class_intersect[cl1][cl2],
1204 (enum reg_class) cl3))
1205 ira_reg_class_intersect[cl1][cl2] = (enum reg_class) cl3;
1207 ira_reg_class_subunion[cl1][cl2] = reg_class_subunion[cl1][cl2];
1208 ira_reg_class_superunion[cl1][cl2] = reg_class_superunion[cl1][cl2];
1209 continue;
1211 ira_reg_classes_intersect_p[cl1][cl2]
1212 = hard_reg_set_intersect_p (temp_hard_regset, temp_set2);
1213 if (important_class_p[cl1] && important_class_p[cl2]
1214 && hard_reg_set_subset_p (temp_hard_regset, temp_set2))
1216 /* CL1 and CL2 are important classes and CL1 allocatable
1217 hard register set is inside of CL2 allocatable hard
1218 registers -- make CL1 a superset of CL2. */
1219 enum reg_class *p;
1221 p = &ira_reg_class_super_classes[cl1][0];
1222 while (*p != LIM_REG_CLASSES)
1223 p++;
1224 *p++ = (enum reg_class) cl2;
1225 *p = LIM_REG_CLASSES;
1227 ira_reg_class_subunion[cl1][cl2] = NO_REGS;
1228 ira_reg_class_superunion[cl1][cl2] = NO_REGS;
1229 COPY_HARD_REG_SET (intersection_set, reg_class_contents[cl1]);
1230 AND_HARD_REG_SET (intersection_set, reg_class_contents[cl2]);
1231 AND_COMPL_HARD_REG_SET (intersection_set, no_unit_alloc_regs);
1232 COPY_HARD_REG_SET (union_set, reg_class_contents[cl1]);
1233 IOR_HARD_REG_SET (union_set, reg_class_contents[cl2]);
1234 AND_COMPL_HARD_REG_SET (union_set, no_unit_alloc_regs);
1235 for (i = 0; i < ira_important_classes_num; i++)
1237 cl3 = ira_important_classes[i];
1238 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl3]);
1239 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
1240 if (hard_reg_set_subset_p (temp_hard_regset, intersection_set))
1242 /* CL3 allocatable hard register set is inside of
1243 intersection of allocatable hard register sets
1244 of CL1 and CL2. */
1245 COPY_HARD_REG_SET
1246 (temp_set2,
1247 reg_class_contents[(int)
1248 ira_reg_class_intersect[cl1][cl2]]);
1249 AND_COMPL_HARD_REG_SET (temp_set2, no_unit_alloc_regs);
1250 if (! hard_reg_set_subset_p (temp_hard_regset, temp_set2)
1251 /* If the allocatable hard register sets are the
1252 same, prefer GENERAL_REGS or the smallest
1253 class for debugging purposes. */
1254 || (hard_reg_set_equal_p (temp_hard_regset, temp_set2)
1255 && (cl3 == GENERAL_REGS
1256 || (ira_reg_class_intersect[cl1][cl2] != GENERAL_REGS
1257 && hard_reg_set_subset_p
1258 (reg_class_contents[cl3],
1259 reg_class_contents
1260 [(int) ira_reg_class_intersect[cl1][cl2]])))))
1261 ira_reg_class_intersect[cl1][cl2] = (enum reg_class) cl3;
1263 if (hard_reg_set_subset_p (temp_hard_regset, union_set))
1265 /* CL3 allocatbale hard register set is inside of
1266 union of allocatable hard register sets of CL1
1267 and CL2. */
1268 COPY_HARD_REG_SET
1269 (temp_set2,
1270 reg_class_contents[(int) ira_reg_class_subunion[cl1][cl2]]);
1271 AND_COMPL_HARD_REG_SET (temp_set2, no_unit_alloc_regs);
1272 if (ira_reg_class_subunion[cl1][cl2] == NO_REGS
1273 || (hard_reg_set_subset_p (temp_set2, temp_hard_regset)
1275 && (! hard_reg_set_equal_p (temp_set2,
1276 temp_hard_regset)
1277 || cl3 == GENERAL_REGS
1278 /* If the allocatable hard register sets are the
1279 same, prefer GENERAL_REGS or the smallest
1280 class for debugging purposes. */
1281 || (ira_reg_class_subunion[cl1][cl2] != GENERAL_REGS
1282 && hard_reg_set_subset_p
1283 (reg_class_contents[cl3],
1284 reg_class_contents
1285 [(int) ira_reg_class_subunion[cl1][cl2]])))))
1286 ira_reg_class_subunion[cl1][cl2] = (enum reg_class) cl3;
1288 if (hard_reg_set_subset_p (union_set, temp_hard_regset))
1290 /* CL3 allocatable hard register set contains union
1291 of allocatable hard register sets of CL1 and
1292 CL2. */
1293 COPY_HARD_REG_SET
1294 (temp_set2,
1295 reg_class_contents[(int) ira_reg_class_superunion[cl1][cl2]]);
1296 AND_COMPL_HARD_REG_SET (temp_set2, no_unit_alloc_regs);
1297 if (ira_reg_class_superunion[cl1][cl2] == NO_REGS
1298 || (hard_reg_set_subset_p (temp_hard_regset, temp_set2)
1300 && (! hard_reg_set_equal_p (temp_set2,
1301 temp_hard_regset)
1302 || cl3 == GENERAL_REGS
1303 /* If the allocatable hard register sets are the
1304 same, prefer GENERAL_REGS or the smallest
1305 class for debugging purposes. */
1306 || (ira_reg_class_superunion[cl1][cl2] != GENERAL_REGS
1307 && hard_reg_set_subset_p
1308 (reg_class_contents[cl3],
1309 reg_class_contents
1310 [(int) ira_reg_class_superunion[cl1][cl2]])))))
1311 ira_reg_class_superunion[cl1][cl2] = (enum reg_class) cl3;
1318 /* Output all possible allocno classes and the translation map into
1319 file F. */
1320 static void
1321 print_classes (FILE *f, bool pressure_p)
1323 int classes_num = (pressure_p
1324 ? ira_pressure_classes_num : ira_allocno_classes_num);
1325 enum reg_class *classes = (pressure_p
1326 ? ira_pressure_classes : ira_allocno_classes);
1327 enum reg_class *class_translate = (pressure_p
1328 ? ira_pressure_class_translate
1329 : ira_allocno_class_translate);
1330 static const char *const reg_class_names[] = REG_CLASS_NAMES;
1331 int i;
1333 fprintf (f, "%s classes:\n", pressure_p ? "Pressure" : "Allocno");
1334 for (i = 0; i < classes_num; i++)
1335 fprintf (f, " %s", reg_class_names[classes[i]]);
1336 fprintf (f, "\nClass translation:\n");
1337 for (i = 0; i < N_REG_CLASSES; i++)
1338 fprintf (f, " %s -> %s\n", reg_class_names[i],
1339 reg_class_names[class_translate[i]]);
1342 /* Output all possible allocno and translation classes and the
1343 translation maps into stderr. */
1344 void
1345 ira_debug_allocno_classes (void)
1347 print_classes (stderr, false);
1348 print_classes (stderr, true);
1351 /* Set up different arrays concerning class subsets, allocno and
1352 important classes. */
1353 static void
1354 find_reg_classes (void)
1356 setup_allocno_and_important_classes ();
1357 setup_class_translate ();
1358 reorder_important_classes ();
1359 setup_reg_class_relations ();
1364 /* Set up the array above. */
1365 static void
1366 setup_hard_regno_aclass (void)
1368 int i;
1370 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1372 #if 1
1373 ira_hard_regno_allocno_class[i]
1374 = (TEST_HARD_REG_BIT (no_unit_alloc_regs, i)
1375 ? NO_REGS
1376 : ira_allocno_class_translate[REGNO_REG_CLASS (i)]);
1377 #else
1378 int j;
1379 enum reg_class cl;
1380 ira_hard_regno_allocno_class[i] = NO_REGS;
1381 for (j = 0; j < ira_allocno_classes_num; j++)
1383 cl = ira_allocno_classes[j];
1384 if (ira_class_hard_reg_index[cl][i] >= 0)
1386 ira_hard_regno_allocno_class[i] = cl;
1387 break;
1390 #endif
1396 /* Form IRA_REG_CLASS_MAX_NREGS and IRA_REG_CLASS_MIN_NREGS maps. */
1397 static void
1398 setup_reg_class_nregs (void)
1400 int i, cl, cl2, m;
1402 for (m = 0; m < MAX_MACHINE_MODE; m++)
1404 for (cl = 0; cl < N_REG_CLASSES; cl++)
1405 ira_reg_class_max_nregs[cl][m]
1406 = ira_reg_class_min_nregs[cl][m]
1407 = targetm.class_max_nregs ((reg_class_t) cl, (enum machine_mode) m);
1408 for (cl = 0; cl < N_REG_CLASSES; cl++)
1409 for (i = 0;
1410 (cl2 = alloc_reg_class_subclasses[cl][i]) != LIM_REG_CLASSES;
1411 i++)
1412 if (ira_reg_class_min_nregs[cl2][m]
1413 < ira_reg_class_min_nregs[cl][m])
1414 ira_reg_class_min_nregs[cl][m] = ira_reg_class_min_nregs[cl2][m];
1420 /* Set up IRA_PROHIBITED_CLASS_MODE_REGS. */
1421 static void
1422 setup_prohibited_class_mode_regs (void)
1424 int j, k, hard_regno, cl;
1426 for (cl = (int) N_REG_CLASSES - 1; cl >= 0; cl--)
1428 for (j = 0; j < NUM_MACHINE_MODES; j++)
1430 CLEAR_HARD_REG_SET (ira_prohibited_class_mode_regs[cl][j]);
1431 for (k = ira_class_hard_regs_num[cl] - 1; k >= 0; k--)
1433 hard_regno = ira_class_hard_regs[cl][k];
1434 if (! HARD_REGNO_MODE_OK (hard_regno, (enum machine_mode) j))
1435 SET_HARD_REG_BIT (ira_prohibited_class_mode_regs[cl][j],
1436 hard_regno);
1442 /* Clarify IRA_PROHIBITED_CLASS_MODE_REGS by excluding hard registers
1443 spanning from one register pressure class to another one. It is
1444 called after defining the pressure classes. */
1445 static void
1446 clarify_prohibited_class_mode_regs (void)
1448 int j, k, hard_regno, cl, pclass, nregs;
1450 for (cl = (int) N_REG_CLASSES - 1; cl >= 0; cl--)
1451 for (j = 0; j < NUM_MACHINE_MODES; j++)
1452 for (k = ira_class_hard_regs_num[cl] - 1; k >= 0; k--)
1454 hard_regno = ira_class_hard_regs[cl][k];
1455 if (TEST_HARD_REG_BIT (ira_prohibited_class_mode_regs[cl][j], hard_regno))
1456 continue;
1457 nregs = hard_regno_nregs[hard_regno][j];
1458 if (hard_regno + nregs > FIRST_PSEUDO_REGISTER)
1460 SET_HARD_REG_BIT (ira_prohibited_class_mode_regs[cl][j],
1461 hard_regno);
1462 continue;
1464 pclass = ira_pressure_class_translate[REGNO_REG_CLASS (hard_regno)];
1465 for (nregs-- ;nregs >= 0; nregs--)
1466 if (((enum reg_class) pclass
1467 != ira_pressure_class_translate[REGNO_REG_CLASS
1468 (hard_regno + nregs)]))
1470 SET_HARD_REG_BIT (ira_prohibited_class_mode_regs[cl][j],
1471 hard_regno);
1472 break;
1479 /* Allocate and initialize IRA_REGISTER_MOVE_COST,
1480 IRA_MAX_REGISTER_MOVE_COST, IRA_MAY_MOVE_IN_COST,
1481 IRA_MAY_MOVE_OUT_COST, IRA_MAX_MAY_MOVE_IN_COST, and
1482 IRA_MAX_MAY_MOVE_OUT_COST for MODE if it is not done yet. */
1483 void
1484 ira_init_register_move_cost (enum machine_mode mode)
1486 int cl1, cl2, cl3;
1488 ira_assert (ira_register_move_cost[mode] == NULL
1489 && ira_max_register_move_cost[mode] == NULL
1490 && ira_may_move_in_cost[mode] == NULL
1491 && ira_may_move_out_cost[mode] == NULL
1492 && ira_max_may_move_in_cost[mode] == NULL
1493 && ira_max_may_move_out_cost[mode] == NULL);
1494 if (move_cost[mode] == NULL)
1495 init_move_cost (mode);
1496 ira_register_move_cost[mode] = move_cost[mode];
1497 /* Don't use ira_allocate because the tables exist out of scope of a
1498 IRA call. */
1499 ira_max_register_move_cost[mode]
1500 = (move_table *) xmalloc (sizeof (move_table) * N_REG_CLASSES);
1501 memcpy (ira_max_register_move_cost[mode], ira_register_move_cost[mode],
1502 sizeof (move_table) * N_REG_CLASSES);
1503 for (cl1 = 0; cl1 < N_REG_CLASSES; cl1++)
1505 /* Some subclasses are to small to have enough registers to hold
1506 a value of MODE. Just ignore them. */
1507 if (ira_reg_class_max_nregs[cl1][mode] > ira_available_class_regs[cl1])
1508 continue;
1509 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl1]);
1510 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
1511 if (hard_reg_set_empty_p (temp_hard_regset))
1512 continue;
1513 for (cl2 = 0; cl2 < N_REG_CLASSES; cl2++)
1514 if (hard_reg_set_subset_p (reg_class_contents[cl1],
1515 reg_class_contents[cl2]))
1516 for (cl3 = 0; cl3 < N_REG_CLASSES; cl3++)
1518 if (ira_max_register_move_cost[mode][cl2][cl3]
1519 < ira_register_move_cost[mode][cl1][cl3])
1520 ira_max_register_move_cost[mode][cl2][cl3]
1521 = ira_register_move_cost[mode][cl1][cl3];
1522 if (ira_max_register_move_cost[mode][cl3][cl2]
1523 < ira_register_move_cost[mode][cl3][cl1])
1524 ira_max_register_move_cost[mode][cl3][cl2]
1525 = ira_register_move_cost[mode][cl3][cl1];
1528 ira_may_move_in_cost[mode]
1529 = (move_table *) xmalloc (sizeof (move_table) * N_REG_CLASSES);
1530 memcpy (ira_may_move_in_cost[mode], may_move_in_cost[mode],
1531 sizeof (move_table) * N_REG_CLASSES);
1532 ira_may_move_out_cost[mode]
1533 = (move_table *) xmalloc (sizeof (move_table) * N_REG_CLASSES);
1534 memcpy (ira_may_move_out_cost[mode], may_move_out_cost[mode],
1535 sizeof (move_table) * N_REG_CLASSES);
1536 ira_max_may_move_in_cost[mode]
1537 = (move_table *) xmalloc (sizeof (move_table) * N_REG_CLASSES);
1538 memcpy (ira_max_may_move_in_cost[mode], ira_max_register_move_cost[mode],
1539 sizeof (move_table) * N_REG_CLASSES);
1540 ira_max_may_move_out_cost[mode]
1541 = (move_table *) xmalloc (sizeof (move_table) * N_REG_CLASSES);
1542 memcpy (ira_max_may_move_out_cost[mode], ira_max_register_move_cost[mode],
1543 sizeof (move_table) * N_REG_CLASSES);
1544 for (cl1 = 0; cl1 < N_REG_CLASSES; cl1++)
1546 for (cl2 = 0; cl2 < N_REG_CLASSES; cl2++)
1548 COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl2]);
1549 AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
1550 if (hard_reg_set_empty_p (temp_hard_regset))
1551 continue;
1552 if (ira_class_subset_p[cl1][cl2])
1553 ira_may_move_in_cost[mode][cl1][cl2] = 0;
1554 if (ira_class_subset_p[cl2][cl1])
1555 ira_may_move_out_cost[mode][cl1][cl2] = 0;
1556 if (ira_class_subset_p[cl1][cl2])
1557 ira_max_may_move_in_cost[mode][cl1][cl2] = 0;
1558 if (ira_class_subset_p[cl2][cl1])
1559 ira_max_may_move_out_cost[mode][cl1][cl2] = 0;
1560 ira_register_move_cost[mode][cl1][cl2]
1561 = ira_max_register_move_cost[mode][cl1][cl2];
1562 ira_may_move_in_cost[mode][cl1][cl2]
1563 = ira_max_may_move_in_cost[mode][cl1][cl2];
1564 ira_may_move_out_cost[mode][cl1][cl2]
1565 = ira_max_may_move_out_cost[mode][cl1][cl2];
1572 /* This is called once during compiler work. It sets up
1573 different arrays whose values don't depend on the compiled
1574 function. */
1575 void
1576 ira_init_once (void)
1578 int mode;
1580 for (mode = 0; mode < MAX_MACHINE_MODE; mode++)
1582 ira_register_move_cost[mode] = NULL;
1583 ira_max_register_move_cost[mode] = NULL;
1584 ira_may_move_in_cost[mode] = NULL;
1585 ira_may_move_out_cost[mode] = NULL;
1586 ira_max_may_move_in_cost[mode] = NULL;
1587 ira_max_may_move_out_cost[mode] = NULL;
1589 ira_init_costs_once ();
1592 /* Free ira_max_register_move_cost, ira_may_move_in_cost,
1593 ira_may_move_out_cost, ira_max_may_move_in_cost, and
1594 ira_max_may_move_out_cost for each mode. */
1595 static void
1596 free_register_move_costs (void)
1598 int mode;
1600 for (mode = 0; mode < MAX_MACHINE_MODE; mode++)
1602 free (ira_max_register_move_cost[mode]);
1603 free (ira_may_move_in_cost[mode]);
1604 free (ira_may_move_out_cost[mode]);
1605 free (ira_max_may_move_in_cost[mode]);
1606 free (ira_max_may_move_out_cost[mode]);
1607 ira_register_move_cost[mode] = NULL;
1608 ira_max_register_move_cost[mode] = NULL;
1609 ira_may_move_in_cost[mode] = NULL;
1610 ira_may_move_out_cost[mode] = NULL;
1611 ira_max_may_move_in_cost[mode] = NULL;
1612 ira_max_may_move_out_cost[mode] = NULL;
1616 /* This is called every time when register related information is
1617 changed. */
1618 void
1619 ira_init (void)
1621 free_register_move_costs ();
1622 setup_reg_mode_hard_regset ();
1623 setup_alloc_regs (flag_omit_frame_pointer != 0);
1624 setup_class_subset_and_memory_move_costs ();
1625 setup_reg_class_nregs ();
1626 setup_prohibited_class_mode_regs ();
1627 find_reg_classes ();
1628 clarify_prohibited_class_mode_regs ();
1629 setup_hard_regno_aclass ();
1630 ira_init_costs ();
1633 /* Function called once at the end of compiler work. */
1634 void
1635 ira_finish_once (void)
1637 ira_finish_costs_once ();
1638 free_register_move_costs ();
1642 #define ira_prohibited_mode_move_regs_initialized_p \
1643 (this_target_ira_int->x_ira_prohibited_mode_move_regs_initialized_p)
1645 /* Set up IRA_PROHIBITED_MODE_MOVE_REGS. */
1646 static void
1647 setup_prohibited_mode_move_regs (void)
1649 int i, j;
1650 rtx test_reg1, test_reg2, move_pat, move_insn;
1652 if (ira_prohibited_mode_move_regs_initialized_p)
1653 return;
1654 ira_prohibited_mode_move_regs_initialized_p = true;
1655 test_reg1 = gen_rtx_REG (VOIDmode, 0);
1656 test_reg2 = gen_rtx_REG (VOIDmode, 0);
1657 move_pat = gen_rtx_SET (VOIDmode, test_reg1, test_reg2);
1658 move_insn = gen_rtx_INSN (VOIDmode, 0, 0, 0, 0, move_pat, 0, -1, 0);
1659 for (i = 0; i < NUM_MACHINE_MODES; i++)
1661 SET_HARD_REG_SET (ira_prohibited_mode_move_regs[i]);
1662 for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
1664 if (! HARD_REGNO_MODE_OK (j, (enum machine_mode) i))
1665 continue;
1666 SET_REGNO_RAW (test_reg1, j);
1667 PUT_MODE (test_reg1, (enum machine_mode) i);
1668 SET_REGNO_RAW (test_reg2, j);
1669 PUT_MODE (test_reg2, (enum machine_mode) i);
1670 INSN_CODE (move_insn) = -1;
1671 recog_memoized (move_insn);
1672 if (INSN_CODE (move_insn) < 0)
1673 continue;
1674 extract_insn (move_insn);
1675 if (! constrain_operands (1))
1676 continue;
1677 CLEAR_HARD_REG_BIT (ira_prohibited_mode_move_regs[i], j);
1684 /* Return nonzero if REGNO is a particularly bad choice for reloading X. */
1685 static bool
1686 ira_bad_reload_regno_1 (int regno, rtx x)
1688 int x_regno, n, i;
1689 ira_allocno_t a;
1690 enum reg_class pref;
1692 /* We only deal with pseudo regs. */
1693 if (! x || GET_CODE (x) != REG)
1694 return false;
1696 x_regno = REGNO (x);
1697 if (x_regno < FIRST_PSEUDO_REGISTER)
1698 return false;
1700 /* If the pseudo prefers REGNO explicitly, then do not consider
1701 REGNO a bad spill choice. */
1702 pref = reg_preferred_class (x_regno);
1703 if (reg_class_size[pref] == 1)
1704 return !TEST_HARD_REG_BIT (reg_class_contents[pref], regno);
1706 /* If the pseudo conflicts with REGNO, then we consider REGNO a
1707 poor choice for a reload regno. */
1708 a = ira_regno_allocno_map[x_regno];
1709 n = ALLOCNO_NUM_OBJECTS (a);
1710 for (i = 0; i < n; i++)
1712 ira_object_t obj = ALLOCNO_OBJECT (a, i);
1713 if (TEST_HARD_REG_BIT (OBJECT_TOTAL_CONFLICT_HARD_REGS (obj), regno))
1714 return true;
1716 return false;
1719 /* Return nonzero if REGNO is a particularly bad choice for reloading
1720 IN or OUT. */
1721 bool
1722 ira_bad_reload_regno (int regno, rtx in, rtx out)
1724 return (ira_bad_reload_regno_1 (regno, in)
1725 || ira_bad_reload_regno_1 (regno, out));
1728 /* Return TRUE if *LOC contains an asm. */
1729 static int
1730 insn_contains_asm_1 (rtx *loc, void *data ATTRIBUTE_UNUSED)
1732 if ( !*loc)
1733 return FALSE;
1734 if (GET_CODE (*loc) == ASM_OPERANDS)
1735 return TRUE;
1736 return FALSE;
1740 /* Return TRUE if INSN contains an ASM. */
1741 static bool
1742 insn_contains_asm (rtx insn)
1744 return for_each_rtx (&insn, insn_contains_asm_1, NULL);
1747 /* Add register clobbers from asm statements. */
1748 static void
1749 compute_regs_asm_clobbered (void)
1751 basic_block bb;
1753 FOR_EACH_BB (bb)
1755 rtx insn;
1756 FOR_BB_INSNS_REVERSE (bb, insn)
1758 df_ref *def_rec;
1760 if (insn_contains_asm (insn))
1761 for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
1763 df_ref def = *def_rec;
1764 unsigned int dregno = DF_REF_REGNO (def);
1765 if (HARD_REGISTER_NUM_P (dregno))
1766 add_to_hard_reg_set (&crtl->asm_clobbers,
1767 GET_MODE (DF_REF_REAL_REG (def)),
1768 dregno);
1775 /* Set up ELIMINABLE_REGSET, IRA_NO_ALLOC_REGS, and REGS_EVER_LIVE. */
1776 void
1777 ira_setup_eliminable_regset (void)
1779 #ifdef ELIMINABLE_REGS
1780 int i;
1781 static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
1782 #endif
1783 /* FIXME: If EXIT_IGNORE_STACK is set, we will not save and restore
1784 sp for alloca. So we can't eliminate the frame pointer in that
1785 case. At some point, we should improve this by emitting the
1786 sp-adjusting insns for this case. */
1787 int need_fp
1788 = (! flag_omit_frame_pointer
1789 || (cfun->calls_alloca && EXIT_IGNORE_STACK)
1790 /* We need the frame pointer to catch stack overflow exceptions
1791 if the stack pointer is moving. */
1792 || (flag_stack_check && STACK_CHECK_MOVING_SP)
1793 || crtl->accesses_prior_frames
1794 || crtl->stack_realign_needed
1795 || targetm.frame_pointer_required ());
1797 frame_pointer_needed = need_fp;
1799 COPY_HARD_REG_SET (ira_no_alloc_regs, no_unit_alloc_regs);
1800 CLEAR_HARD_REG_SET (eliminable_regset);
1802 compute_regs_asm_clobbered ();
1804 /* Build the regset of all eliminable registers and show we can't
1805 use those that we already know won't be eliminated. */
1806 #ifdef ELIMINABLE_REGS
1807 for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
1809 bool cannot_elim
1810 = (! targetm.can_eliminate (eliminables[i].from, eliminables[i].to)
1811 || (eliminables[i].to == STACK_POINTER_REGNUM && need_fp));
1813 if (!TEST_HARD_REG_BIT (crtl->asm_clobbers, eliminables[i].from))
1815 SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from);
1817 if (cannot_elim)
1818 SET_HARD_REG_BIT (ira_no_alloc_regs, eliminables[i].from);
1820 else if (cannot_elim)
1821 error ("%s cannot be used in asm here",
1822 reg_names[eliminables[i].from]);
1823 else
1824 df_set_regs_ever_live (eliminables[i].from, true);
1826 #if !HARD_FRAME_POINTER_IS_FRAME_POINTER
1827 if (!TEST_HARD_REG_BIT (crtl->asm_clobbers, HARD_FRAME_POINTER_REGNUM))
1829 SET_HARD_REG_BIT (eliminable_regset, HARD_FRAME_POINTER_REGNUM);
1830 if (need_fp)
1831 SET_HARD_REG_BIT (ira_no_alloc_regs, HARD_FRAME_POINTER_REGNUM);
1833 else if (need_fp)
1834 error ("%s cannot be used in asm here",
1835 reg_names[HARD_FRAME_POINTER_REGNUM]);
1836 else
1837 df_set_regs_ever_live (HARD_FRAME_POINTER_REGNUM, true);
1838 #endif
1840 #else
1841 if (!TEST_HARD_REG_BIT (crtl->asm_clobbers, HARD_FRAME_POINTER_REGNUM))
1843 SET_HARD_REG_BIT (eliminable_regset, FRAME_POINTER_REGNUM);
1844 if (need_fp)
1845 SET_HARD_REG_BIT (ira_no_alloc_regs, FRAME_POINTER_REGNUM);
1847 else if (need_fp)
1848 error ("%s cannot be used in asm here", reg_names[FRAME_POINTER_REGNUM]);
1849 else
1850 df_set_regs_ever_live (FRAME_POINTER_REGNUM, true);
1851 #endif
1856 /* The length of the following two arrays. */
1857 int ira_reg_equiv_len;
1859 /* The element value is TRUE if the corresponding regno value is
1860 invariant. */
1861 bool *ira_reg_equiv_invariant_p;
1863 /* The element value is equiv constant of given pseudo-register or
1864 NULL_RTX. */
1865 rtx *ira_reg_equiv_const;
1867 /* Set up the two arrays declared above. */
1868 static void
1869 find_reg_equiv_invariant_const (void)
1871 unsigned int i;
1872 bool invariant_p;
1873 rtx list, insn, note, constant, x;
1875 for (i = FIRST_PSEUDO_REGISTER; i < VEC_length (reg_equivs_t, reg_equivs); i++)
1877 constant = NULL_RTX;
1878 invariant_p = false;
1879 for (list = reg_equiv_init (i); list != NULL_RTX; list = XEXP (list, 1))
1881 insn = XEXP (list, 0);
1882 note = find_reg_note (insn, REG_EQUIV, NULL_RTX);
1884 if (note == NULL_RTX)
1885 continue;
1887 x = XEXP (note, 0);
1889 if (! CONSTANT_P (x)
1890 || ! flag_pic || LEGITIMATE_PIC_OPERAND_P (x))
1892 /* It can happen that a REG_EQUIV note contains a MEM
1893 that is not a legitimate memory operand. As later
1894 stages of the reload assume that all addresses found
1895 in the reg_equiv_* arrays were originally legitimate,
1896 we ignore such REG_EQUIV notes. */
1897 if (memory_operand (x, VOIDmode))
1898 invariant_p = MEM_READONLY_P (x);
1899 else if (function_invariant_p (x))
1901 if (GET_CODE (x) == PLUS
1902 || x == frame_pointer_rtx || x == arg_pointer_rtx)
1903 invariant_p = true;
1904 else
1905 constant = x;
1909 ira_reg_equiv_invariant_p[i] = invariant_p;
1910 ira_reg_equiv_const[i] = constant;
1916 /* Vector of substitutions of register numbers,
1917 used to map pseudo regs into hardware regs.
1918 This is set up as a result of register allocation.
1919 Element N is the hard reg assigned to pseudo reg N,
1920 or is -1 if no hard reg was assigned.
1921 If N is a hard reg number, element N is N. */
1922 short *reg_renumber;
1924 /* Set up REG_RENUMBER and CALLER_SAVE_NEEDED (used by reload) from
1925 the allocation found by IRA. */
1926 static void
1927 setup_reg_renumber (void)
1929 int regno, hard_regno;
1930 ira_allocno_t a;
1931 ira_allocno_iterator ai;
1933 caller_save_needed = 0;
1934 FOR_EACH_ALLOCNO (a, ai)
1936 /* There are no caps at this point. */
1937 ira_assert (ALLOCNO_CAP_MEMBER (a) == NULL);
1938 if (! ALLOCNO_ASSIGNED_P (a))
1939 /* It can happen if A is not referenced but partially anticipated
1940 somewhere in a region. */
1941 ALLOCNO_ASSIGNED_P (a) = true;
1942 ira_free_allocno_updated_costs (a);
1943 hard_regno = ALLOCNO_HARD_REGNO (a);
1944 regno = ALLOCNO_REGNO (a);
1945 reg_renumber[regno] = (hard_regno < 0 ? -1 : hard_regno);
1946 if (hard_regno >= 0)
1948 int i, nwords;
1949 enum reg_class pclass;
1950 ira_object_t obj;
1952 pclass = ira_pressure_class_translate[REGNO_REG_CLASS (hard_regno)];
1953 nwords = ALLOCNO_NUM_OBJECTS (a);
1954 for (i = 0; i < nwords; i++)
1956 obj = ALLOCNO_OBJECT (a, i);
1957 IOR_COMPL_HARD_REG_SET (OBJECT_TOTAL_CONFLICT_HARD_REGS (obj),
1958 reg_class_contents[pclass]);
1960 if (ALLOCNO_CALLS_CROSSED_NUM (a) != 0
1961 && ira_hard_reg_set_intersection_p (hard_regno, ALLOCNO_MODE (a),
1962 call_used_reg_set))
1964 ira_assert (!optimize || flag_caller_saves
1965 || regno >= ira_reg_equiv_len
1966 || ira_reg_equiv_const[regno]
1967 || ira_reg_equiv_invariant_p[regno]);
1968 caller_save_needed = 1;
1974 /* Set up allocno assignment flags for further allocation
1975 improvements. */
1976 static void
1977 setup_allocno_assignment_flags (void)
1979 int hard_regno;
1980 ira_allocno_t a;
1981 ira_allocno_iterator ai;
1983 FOR_EACH_ALLOCNO (a, ai)
1985 if (! ALLOCNO_ASSIGNED_P (a))
1986 /* It can happen if A is not referenced but partially anticipated
1987 somewhere in a region. */
1988 ira_free_allocno_updated_costs (a);
1989 hard_regno = ALLOCNO_HARD_REGNO (a);
1990 /* Don't assign hard registers to allocnos which are destination
1991 of removed store at the end of loop. It has no sense to keep
1992 the same value in different hard registers. It is also
1993 impossible to assign hard registers correctly to such
1994 allocnos because the cost info and info about intersected
1995 calls are incorrect for them. */
1996 ALLOCNO_ASSIGNED_P (a) = (hard_regno >= 0
1997 || ALLOCNO_EMIT_DATA (a)->mem_optimized_dest_p
1998 || (ALLOCNO_MEMORY_COST (a)
1999 - ALLOCNO_CLASS_COST (a)) < 0);
2000 ira_assert
2001 (hard_regno < 0
2002 || ira_hard_reg_in_set_p (hard_regno, ALLOCNO_MODE (a),
2003 reg_class_contents[ALLOCNO_CLASS (a)]));
2007 /* Evaluate overall allocation cost and the costs for using hard
2008 registers and memory for allocnos. */
2009 static void
2010 calculate_allocation_cost (void)
2012 int hard_regno, cost;
2013 ira_allocno_t a;
2014 ira_allocno_iterator ai;
2016 ira_overall_cost = ira_reg_cost = ira_mem_cost = 0;
2017 FOR_EACH_ALLOCNO (a, ai)
2019 hard_regno = ALLOCNO_HARD_REGNO (a);
2020 ira_assert (hard_regno < 0
2021 || (ira_hard_reg_in_set_p
2022 (hard_regno, ALLOCNO_MODE (a),
2023 reg_class_contents[ALLOCNO_CLASS (a)])));
2024 if (hard_regno < 0)
2026 cost = ALLOCNO_MEMORY_COST (a);
2027 ira_mem_cost += cost;
2029 else if (ALLOCNO_HARD_REG_COSTS (a) != NULL)
2031 cost = (ALLOCNO_HARD_REG_COSTS (a)
2032 [ira_class_hard_reg_index
2033 [ALLOCNO_CLASS (a)][hard_regno]]);
2034 ira_reg_cost += cost;
2036 else
2038 cost = ALLOCNO_CLASS_COST (a);
2039 ira_reg_cost += cost;
2041 ira_overall_cost += cost;
2044 if (internal_flag_ira_verbose > 0 && ira_dump_file != NULL)
2046 fprintf (ira_dump_file,
2047 "+++Costs: overall %d, reg %d, mem %d, ld %d, st %d, move %d\n",
2048 ira_overall_cost, ira_reg_cost, ira_mem_cost,
2049 ira_load_cost, ira_store_cost, ira_shuffle_cost);
2050 fprintf (ira_dump_file, "+++ move loops %d, new jumps %d\n",
2051 ira_move_loops_num, ira_additional_jumps_num);
2056 #ifdef ENABLE_IRA_CHECKING
2057 /* Check the correctness of the allocation. We do need this because
2058 of complicated code to transform more one region internal
2059 representation into one region representation. */
2060 static void
2061 check_allocation (void)
2063 ira_allocno_t a;
2064 int hard_regno, nregs, conflict_nregs;
2065 ira_allocno_iterator ai;
2067 FOR_EACH_ALLOCNO (a, ai)
2069 int n = ALLOCNO_NUM_OBJECTS (a);
2070 int i;
2072 if (ALLOCNO_CAP_MEMBER (a) != NULL
2073 || (hard_regno = ALLOCNO_HARD_REGNO (a)) < 0)
2074 continue;
2075 nregs = hard_regno_nregs[hard_regno][ALLOCNO_MODE (a)];
2076 if (nregs == 1)
2077 /* We allocated a single hard register. */
2078 n = 1;
2079 else if (n > 1)
2080 /* We allocated multiple hard registers, and we will test
2081 conflicts in a granularity of single hard regs. */
2082 nregs = 1;
2084 for (i = 0; i < n; i++)
2086 ira_object_t obj = ALLOCNO_OBJECT (a, i);
2087 ira_object_t conflict_obj;
2088 ira_object_conflict_iterator oci;
2089 int this_regno = hard_regno;
2090 if (n > 1)
2092 if (REG_WORDS_BIG_ENDIAN)
2093 this_regno += n - i - 1;
2094 else
2095 this_regno += i;
2097 FOR_EACH_OBJECT_CONFLICT (obj, conflict_obj, oci)
2099 ira_allocno_t conflict_a = OBJECT_ALLOCNO (conflict_obj);
2100 int conflict_hard_regno = ALLOCNO_HARD_REGNO (conflict_a);
2101 if (conflict_hard_regno < 0)
2102 continue;
2104 conflict_nregs
2105 = (hard_regno_nregs
2106 [conflict_hard_regno][ALLOCNO_MODE (conflict_a)]);
2108 if (ALLOCNO_NUM_OBJECTS (conflict_a) > 1
2109 && conflict_nregs == ALLOCNO_NUM_OBJECTS (conflict_a))
2111 if (REG_WORDS_BIG_ENDIAN)
2112 conflict_hard_regno += (ALLOCNO_NUM_OBJECTS (conflict_a)
2113 - OBJECT_SUBWORD (conflict_obj) - 1);
2114 else
2115 conflict_hard_regno += OBJECT_SUBWORD (conflict_obj);
2116 conflict_nregs = 1;
2119 if ((conflict_hard_regno <= this_regno
2120 && this_regno < conflict_hard_regno + conflict_nregs)
2121 || (this_regno <= conflict_hard_regno
2122 && conflict_hard_regno < this_regno + nregs))
2124 fprintf (stderr, "bad allocation for %d and %d\n",
2125 ALLOCNO_REGNO (a), ALLOCNO_REGNO (conflict_a));
2126 gcc_unreachable ();
2132 #endif
2134 /* Fix values of array REG_EQUIV_INIT after live range splitting done
2135 by IRA. */
2136 static void
2137 fix_reg_equiv_init (void)
2139 unsigned int max_regno = max_reg_num ();
2140 int i, new_regno, max;
2141 rtx x, prev, next, insn, set;
2143 if (VEC_length (reg_equivs_t, reg_equivs) < max_regno)
2145 max = VEC_length (reg_equivs_t, reg_equivs);
2146 grow_reg_equivs ();
2147 for (i = FIRST_PSEUDO_REGISTER; i < max; i++)
2148 for (prev = NULL_RTX, x = reg_equiv_init (i);
2149 x != NULL_RTX;
2150 x = next)
2152 next = XEXP (x, 1);
2153 insn = XEXP (x, 0);
2154 set = single_set (insn);
2155 ira_assert (set != NULL_RTX
2156 && (REG_P (SET_DEST (set)) || REG_P (SET_SRC (set))));
2157 if (REG_P (SET_DEST (set))
2158 && ((int) REGNO (SET_DEST (set)) == i
2159 || (int) ORIGINAL_REGNO (SET_DEST (set)) == i))
2160 new_regno = REGNO (SET_DEST (set));
2161 else if (REG_P (SET_SRC (set))
2162 && ((int) REGNO (SET_SRC (set)) == i
2163 || (int) ORIGINAL_REGNO (SET_SRC (set)) == i))
2164 new_regno = REGNO (SET_SRC (set));
2165 else
2166 gcc_unreachable ();
2167 if (new_regno == i)
2168 prev = x;
2169 else
2171 if (prev == NULL_RTX)
2172 reg_equiv_init (i) = next;
2173 else
2174 XEXP (prev, 1) = next;
2175 XEXP (x, 1) = reg_equiv_init (new_regno);
2176 reg_equiv_init (new_regno) = x;
2182 #ifdef ENABLE_IRA_CHECKING
2183 /* Print redundant memory-memory copies. */
2184 static void
2185 print_redundant_copies (void)
2187 int hard_regno;
2188 ira_allocno_t a;
2189 ira_copy_t cp, next_cp;
2190 ira_allocno_iterator ai;
2192 FOR_EACH_ALLOCNO (a, ai)
2194 if (ALLOCNO_CAP_MEMBER (a) != NULL)
2195 /* It is a cap. */
2196 continue;
2197 hard_regno = ALLOCNO_HARD_REGNO (a);
2198 if (hard_regno >= 0)
2199 continue;
2200 for (cp = ALLOCNO_COPIES (a); cp != NULL; cp = next_cp)
2201 if (cp->first == a)
2202 next_cp = cp->next_first_allocno_copy;
2203 else
2205 next_cp = cp->next_second_allocno_copy;
2206 if (internal_flag_ira_verbose > 4 && ira_dump_file != NULL
2207 && cp->insn != NULL_RTX
2208 && ALLOCNO_HARD_REGNO (cp->first) == hard_regno)
2209 fprintf (ira_dump_file,
2210 " Redundant move from %d(freq %d):%d\n",
2211 INSN_UID (cp->insn), cp->freq, hard_regno);
2215 #endif
2217 /* Setup preferred and alternative classes for new pseudo-registers
2218 created by IRA starting with START. */
2219 static void
2220 setup_preferred_alternate_classes_for_new_pseudos (int start)
2222 int i, old_regno;
2223 int max_regno = max_reg_num ();
2225 for (i = start; i < max_regno; i++)
2227 old_regno = ORIGINAL_REGNO (regno_reg_rtx[i]);
2228 ira_assert (i != old_regno);
2229 setup_reg_classes (i, reg_preferred_class (old_regno),
2230 reg_alternate_class (old_regno),
2231 reg_allocno_class (old_regno));
2232 if (internal_flag_ira_verbose > 2 && ira_dump_file != NULL)
2233 fprintf (ira_dump_file,
2234 " New r%d: setting preferred %s, alternative %s\n",
2235 i, reg_class_names[reg_preferred_class (old_regno)],
2236 reg_class_names[reg_alternate_class (old_regno)]);
2242 /* Regional allocation can create new pseudo-registers. This function
2243 expands some arrays for pseudo-registers. */
2244 static void
2245 expand_reg_info (int old_size)
2247 int i;
2248 int size = max_reg_num ();
2250 resize_reg_info ();
2251 for (i = old_size; i < size; i++)
2252 setup_reg_classes (i, GENERAL_REGS, ALL_REGS, GENERAL_REGS);
2255 /* Return TRUE if there is too high register pressure in the function.
2256 It is used to decide when stack slot sharing is worth to do. */
2257 static bool
2258 too_high_register_pressure_p (void)
2260 int i;
2261 enum reg_class pclass;
2263 for (i = 0; i < ira_pressure_classes_num; i++)
2265 pclass = ira_pressure_classes[i];
2266 if (ira_loop_tree_root->reg_pressure[pclass] > 10000)
2267 return true;
2269 return false;
2274 /* Indicate that hard register number FROM was eliminated and replaced with
2275 an offset from hard register number TO. The status of hard registers live
2276 at the start of a basic block is updated by replacing a use of FROM with
2277 a use of TO. */
2279 void
2280 mark_elimination (int from, int to)
2282 basic_block bb;
2284 FOR_EACH_BB (bb)
2286 /* We don't use LIVE info in IRA. */
2287 bitmap r = DF_LR_IN (bb);
2289 if (REGNO_REG_SET_P (r, from))
2291 CLEAR_REGNO_REG_SET (r, from);
2292 SET_REGNO_REG_SET (r, to);
2299 struct equivalence
2301 /* Set when a REG_EQUIV note is found or created. Use to
2302 keep track of what memory accesses might be created later,
2303 e.g. by reload. */
2304 rtx replacement;
2305 rtx *src_p;
2306 /* The list of each instruction which initializes this register. */
2307 rtx init_insns;
2308 /* Loop depth is used to recognize equivalences which appear
2309 to be present within the same loop (or in an inner loop). */
2310 int loop_depth;
2311 /* Nonzero if this had a preexisting REG_EQUIV note. */
2312 int is_arg_equivalence;
2313 /* Set when an attempt should be made to replace a register
2314 with the associated src_p entry. */
2315 char replace;
2318 /* reg_equiv[N] (where N is a pseudo reg number) is the equivalence
2319 structure for that register. */
2320 static struct equivalence *reg_equiv;
2322 /* Used for communication between the following two functions: contains
2323 a MEM that we wish to ensure remains unchanged. */
2324 static rtx equiv_mem;
2326 /* Set nonzero if EQUIV_MEM is modified. */
2327 static int equiv_mem_modified;
2329 /* If EQUIV_MEM is modified by modifying DEST, indicate that it is modified.
2330 Called via note_stores. */
2331 static void
2332 validate_equiv_mem_from_store (rtx dest, const_rtx set ATTRIBUTE_UNUSED,
2333 void *data ATTRIBUTE_UNUSED)
2335 if ((REG_P (dest)
2336 && reg_overlap_mentioned_p (dest, equiv_mem))
2337 || (MEM_P (dest)
2338 && true_dependence (dest, VOIDmode, equiv_mem)))
2339 equiv_mem_modified = 1;
2342 /* Verify that no store between START and the death of REG invalidates
2343 MEMREF. MEMREF is invalidated by modifying a register used in MEMREF,
2344 by storing into an overlapping memory location, or with a non-const
2345 CALL_INSN.
2347 Return 1 if MEMREF remains valid. */
2348 static int
2349 validate_equiv_mem (rtx start, rtx reg, rtx memref)
2351 rtx insn;
2352 rtx note;
2354 equiv_mem = memref;
2355 equiv_mem_modified = 0;
2357 /* If the memory reference has side effects or is volatile, it isn't a
2358 valid equivalence. */
2359 if (side_effects_p (memref))
2360 return 0;
2362 for (insn = start; insn && ! equiv_mem_modified; insn = NEXT_INSN (insn))
2364 if (! INSN_P (insn))
2365 continue;
2367 if (find_reg_note (insn, REG_DEAD, reg))
2368 return 1;
2370 /* This used to ignore readonly memory and const/pure calls. The problem
2371 is the equivalent form may reference a pseudo which gets assigned a
2372 call clobbered hard reg. When we later replace REG with its
2373 equivalent form, the value in the call-clobbered reg has been
2374 changed and all hell breaks loose. */
2375 if (CALL_P (insn))
2376 return 0;
2378 note_stores (PATTERN (insn), validate_equiv_mem_from_store, NULL);
2380 /* If a register mentioned in MEMREF is modified via an
2381 auto-increment, we lose the equivalence. Do the same if one
2382 dies; although we could extend the life, it doesn't seem worth
2383 the trouble. */
2385 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2386 if ((REG_NOTE_KIND (note) == REG_INC
2387 || REG_NOTE_KIND (note) == REG_DEAD)
2388 && REG_P (XEXP (note, 0))
2389 && reg_overlap_mentioned_p (XEXP (note, 0), memref))
2390 return 0;
2393 return 0;
2396 /* Returns zero if X is known to be invariant. */
2397 static int
2398 equiv_init_varies_p (rtx x)
2400 RTX_CODE code = GET_CODE (x);
2401 int i;
2402 const char *fmt;
2404 switch (code)
2406 case MEM:
2407 return !MEM_READONLY_P (x) || equiv_init_varies_p (XEXP (x, 0));
2409 case CONST:
2410 case CONST_INT:
2411 case CONST_DOUBLE:
2412 case CONST_FIXED:
2413 case CONST_VECTOR:
2414 case SYMBOL_REF:
2415 case LABEL_REF:
2416 return 0;
2418 case REG:
2419 return reg_equiv[REGNO (x)].replace == 0 && rtx_varies_p (x, 0);
2421 case ASM_OPERANDS:
2422 if (MEM_VOLATILE_P (x))
2423 return 1;
2425 /* Fall through. */
2427 default:
2428 break;
2431 fmt = GET_RTX_FORMAT (code);
2432 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2433 if (fmt[i] == 'e')
2435 if (equiv_init_varies_p (XEXP (x, i)))
2436 return 1;
2438 else if (fmt[i] == 'E')
2440 int j;
2441 for (j = 0; j < XVECLEN (x, i); j++)
2442 if (equiv_init_varies_p (XVECEXP (x, i, j)))
2443 return 1;
2446 return 0;
2449 /* Returns nonzero if X (used to initialize register REGNO) is movable.
2450 X is only movable if the registers it uses have equivalent initializations
2451 which appear to be within the same loop (or in an inner loop) and movable
2452 or if they are not candidates for local_alloc and don't vary. */
2453 static int
2454 equiv_init_movable_p (rtx x, int regno)
2456 int i, j;
2457 const char *fmt;
2458 enum rtx_code code = GET_CODE (x);
2460 switch (code)
2462 case SET:
2463 return equiv_init_movable_p (SET_SRC (x), regno);
2465 case CC0:
2466 case CLOBBER:
2467 return 0;
2469 case PRE_INC:
2470 case PRE_DEC:
2471 case POST_INC:
2472 case POST_DEC:
2473 case PRE_MODIFY:
2474 case POST_MODIFY:
2475 return 0;
2477 case REG:
2478 return ((reg_equiv[REGNO (x)].loop_depth >= reg_equiv[regno].loop_depth
2479 && reg_equiv[REGNO (x)].replace)
2480 || (REG_BASIC_BLOCK (REGNO (x)) < NUM_FIXED_BLOCKS
2481 && ! rtx_varies_p (x, 0)));
2483 case UNSPEC_VOLATILE:
2484 return 0;
2486 case ASM_OPERANDS:
2487 if (MEM_VOLATILE_P (x))
2488 return 0;
2490 /* Fall through. */
2492 default:
2493 break;
2496 fmt = GET_RTX_FORMAT (code);
2497 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2498 switch (fmt[i])
2500 case 'e':
2501 if (! equiv_init_movable_p (XEXP (x, i), regno))
2502 return 0;
2503 break;
2504 case 'E':
2505 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
2506 if (! equiv_init_movable_p (XVECEXP (x, i, j), regno))
2507 return 0;
2508 break;
2511 return 1;
2514 /* TRUE if X uses any registers for which reg_equiv[REGNO].replace is
2515 true. */
2516 static int
2517 contains_replace_regs (rtx x)
2519 int i, j;
2520 const char *fmt;
2521 enum rtx_code code = GET_CODE (x);
2523 switch (code)
2525 case CONST_INT:
2526 case CONST:
2527 case LABEL_REF:
2528 case SYMBOL_REF:
2529 case CONST_DOUBLE:
2530 case CONST_FIXED:
2531 case CONST_VECTOR:
2532 case PC:
2533 case CC0:
2534 case HIGH:
2535 return 0;
2537 case REG:
2538 return reg_equiv[REGNO (x)].replace;
2540 default:
2541 break;
2544 fmt = GET_RTX_FORMAT (code);
2545 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2546 switch (fmt[i])
2548 case 'e':
2549 if (contains_replace_regs (XEXP (x, i)))
2550 return 1;
2551 break;
2552 case 'E':
2553 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
2554 if (contains_replace_regs (XVECEXP (x, i, j)))
2555 return 1;
2556 break;
2559 return 0;
2562 /* TRUE if X references a memory location that would be affected by a store
2563 to MEMREF. */
2564 static int
2565 memref_referenced_p (rtx memref, rtx x)
2567 int i, j;
2568 const char *fmt;
2569 enum rtx_code code = GET_CODE (x);
2571 switch (code)
2573 case CONST_INT:
2574 case CONST:
2575 case LABEL_REF:
2576 case SYMBOL_REF:
2577 case CONST_DOUBLE:
2578 case CONST_FIXED:
2579 case CONST_VECTOR:
2580 case PC:
2581 case CC0:
2582 case HIGH:
2583 case LO_SUM:
2584 return 0;
2586 case REG:
2587 return (reg_equiv[REGNO (x)].replacement
2588 && memref_referenced_p (memref,
2589 reg_equiv[REGNO (x)].replacement));
2591 case MEM:
2592 if (true_dependence (memref, VOIDmode, x))
2593 return 1;
2594 break;
2596 case SET:
2597 /* If we are setting a MEM, it doesn't count (its address does), but any
2598 other SET_DEST that has a MEM in it is referencing the MEM. */
2599 if (MEM_P (SET_DEST (x)))
2601 if (memref_referenced_p (memref, XEXP (SET_DEST (x), 0)))
2602 return 1;
2604 else if (memref_referenced_p (memref, SET_DEST (x)))
2605 return 1;
2607 return memref_referenced_p (memref, SET_SRC (x));
2609 default:
2610 break;
2613 fmt = GET_RTX_FORMAT (code);
2614 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
2615 switch (fmt[i])
2617 case 'e':
2618 if (memref_referenced_p (memref, XEXP (x, i)))
2619 return 1;
2620 break;
2621 case 'E':
2622 for (j = XVECLEN (x, i) - 1; j >= 0; j--)
2623 if (memref_referenced_p (memref, XVECEXP (x, i, j)))
2624 return 1;
2625 break;
2628 return 0;
2631 /* TRUE if some insn in the range (START, END] references a memory location
2632 that would be affected by a store to MEMREF. */
2633 static int
2634 memref_used_between_p (rtx memref, rtx start, rtx end)
2636 rtx insn;
2638 for (insn = NEXT_INSN (start); insn != NEXT_INSN (end);
2639 insn = NEXT_INSN (insn))
2641 if (!NONDEBUG_INSN_P (insn))
2642 continue;
2644 if (memref_referenced_p (memref, PATTERN (insn)))
2645 return 1;
2647 /* Nonconst functions may access memory. */
2648 if (CALL_P (insn) && (! RTL_CONST_CALL_P (insn)))
2649 return 1;
2652 return 0;
2655 /* Mark REG as having no known equivalence.
2656 Some instructions might have been processed before and furnished
2657 with REG_EQUIV notes for this register; these notes will have to be
2658 removed.
2659 STORE is the piece of RTL that does the non-constant / conflicting
2660 assignment - a SET, CLOBBER or REG_INC note. It is currently not used,
2661 but needs to be there because this function is called from note_stores. */
2662 static void
2663 no_equiv (rtx reg, const_rtx store ATTRIBUTE_UNUSED,
2664 void *data ATTRIBUTE_UNUSED)
2666 int regno;
2667 rtx list;
2669 if (!REG_P (reg))
2670 return;
2671 regno = REGNO (reg);
2672 list = reg_equiv[regno].init_insns;
2673 if (list == const0_rtx)
2674 return;
2675 reg_equiv[regno].init_insns = const0_rtx;
2676 reg_equiv[regno].replacement = NULL_RTX;
2677 /* This doesn't matter for equivalences made for argument registers, we
2678 should keep their initialization insns. */
2679 if (reg_equiv[regno].is_arg_equivalence)
2680 return;
2681 reg_equiv_init (regno) = NULL_RTX;
2682 for (; list; list = XEXP (list, 1))
2684 rtx insn = XEXP (list, 0);
2685 remove_note (insn, find_reg_note (insn, REG_EQUIV, NULL_RTX));
2689 /* In DEBUG_INSN location adjust REGs from CLEARED_REGS bitmap to the
2690 equivalent replacement. */
2692 static rtx
2693 adjust_cleared_regs (rtx loc, const_rtx old_rtx ATTRIBUTE_UNUSED, void *data)
2695 if (REG_P (loc))
2697 bitmap cleared_regs = (bitmap) data;
2698 if (bitmap_bit_p (cleared_regs, REGNO (loc)))
2699 return simplify_replace_fn_rtx (*reg_equiv[REGNO (loc)].src_p,
2700 NULL_RTX, adjust_cleared_regs, data);
2702 return NULL_RTX;
2705 /* Nonzero if we recorded an equivalence for a LABEL_REF. */
2706 static int recorded_label_ref;
2708 /* Find registers that are equivalent to a single value throughout the
2709 compilation (either because they can be referenced in memory or are
2710 set once from a single constant). Lower their priority for a
2711 register.
2713 If such a register is only referenced once, try substituting its
2714 value into the using insn. If it succeeds, we can eliminate the
2715 register completely.
2717 Initialize the REG_EQUIV_INIT array of initializing insns.
2719 Return non-zero if jump label rebuilding should be done. */
2720 static int
2721 update_equiv_regs (void)
2723 rtx insn;
2724 basic_block bb;
2725 int loop_depth;
2726 bitmap cleared_regs;
2728 /* We need to keep track of whether or not we recorded a LABEL_REF so
2729 that we know if the jump optimizer needs to be rerun. */
2730 recorded_label_ref = 0;
2732 reg_equiv = XCNEWVEC (struct equivalence, max_regno);
2733 grow_reg_equivs ();
2735 init_alias_analysis ();
2737 /* Scan the insns and find which registers have equivalences. Do this
2738 in a separate scan of the insns because (due to -fcse-follow-jumps)
2739 a register can be set below its use. */
2740 FOR_EACH_BB (bb)
2742 loop_depth = bb->loop_depth;
2744 for (insn = BB_HEAD (bb);
2745 insn != NEXT_INSN (BB_END (bb));
2746 insn = NEXT_INSN (insn))
2748 rtx note;
2749 rtx set;
2750 rtx dest, src;
2751 int regno;
2753 if (! INSN_P (insn))
2754 continue;
2756 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
2757 if (REG_NOTE_KIND (note) == REG_INC)
2758 no_equiv (XEXP (note, 0), note, NULL);
2760 set = single_set (insn);
2762 /* If this insn contains more (or less) than a single SET,
2763 only mark all destinations as having no known equivalence. */
2764 if (set == 0)
2766 note_stores (PATTERN (insn), no_equiv, NULL);
2767 continue;
2769 else if (GET_CODE (PATTERN (insn)) == PARALLEL)
2771 int i;
2773 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
2775 rtx part = XVECEXP (PATTERN (insn), 0, i);
2776 if (part != set)
2777 note_stores (part, no_equiv, NULL);
2781 dest = SET_DEST (set);
2782 src = SET_SRC (set);
2784 /* See if this is setting up the equivalence between an argument
2785 register and its stack slot. */
2786 note = find_reg_note (insn, REG_EQUIV, NULL_RTX);
2787 if (note)
2789 gcc_assert (REG_P (dest));
2790 regno = REGNO (dest);
2792 /* Note that we don't want to clear reg_equiv_init even if there
2793 are multiple sets of this register. */
2794 reg_equiv[regno].is_arg_equivalence = 1;
2796 /* Record for reload that this is an equivalencing insn. */
2797 if (rtx_equal_p (src, XEXP (note, 0)))
2798 reg_equiv_init (regno)
2799 = gen_rtx_INSN_LIST (VOIDmode, insn, reg_equiv_init (regno));
2801 /* Continue normally in case this is a candidate for
2802 replacements. */
2805 if (!optimize)
2806 continue;
2808 /* We only handle the case of a pseudo register being set
2809 once, or always to the same value. */
2810 /* ??? The mn10200 port breaks if we add equivalences for
2811 values that need an ADDRESS_REGS register and set them equivalent
2812 to a MEM of a pseudo. The actual problem is in the over-conservative
2813 handling of INPADDR_ADDRESS / INPUT_ADDRESS / INPUT triples in
2814 calculate_needs, but we traditionally work around this problem
2815 here by rejecting equivalences when the destination is in a register
2816 that's likely spilled. This is fragile, of course, since the
2817 preferred class of a pseudo depends on all instructions that set
2818 or use it. */
2820 if (!REG_P (dest)
2821 || (regno = REGNO (dest)) < FIRST_PSEUDO_REGISTER
2822 || reg_equiv[regno].init_insns == const0_rtx
2823 || (targetm.class_likely_spilled_p (reg_preferred_class (regno))
2824 && MEM_P (src) && ! reg_equiv[regno].is_arg_equivalence))
2826 /* This might be setting a SUBREG of a pseudo, a pseudo that is
2827 also set somewhere else to a constant. */
2828 note_stores (set, no_equiv, NULL);
2829 continue;
2832 note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
2834 /* cse sometimes generates function invariants, but doesn't put a
2835 REG_EQUAL note on the insn. Since this note would be redundant,
2836 there's no point creating it earlier than here. */
2837 if (! note && ! rtx_varies_p (src, 0))
2838 note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
2840 /* Don't bother considering a REG_EQUAL note containing an EXPR_LIST
2841 since it represents a function call */
2842 if (note && GET_CODE (XEXP (note, 0)) == EXPR_LIST)
2843 note = NULL_RTX;
2845 if (DF_REG_DEF_COUNT (regno) != 1
2846 && (! note
2847 || rtx_varies_p (XEXP (note, 0), 0)
2848 || (reg_equiv[regno].replacement
2849 && ! rtx_equal_p (XEXP (note, 0),
2850 reg_equiv[regno].replacement))))
2852 no_equiv (dest, set, NULL);
2853 continue;
2855 /* Record this insn as initializing this register. */
2856 reg_equiv[regno].init_insns
2857 = gen_rtx_INSN_LIST (VOIDmode, insn, reg_equiv[regno].init_insns);
2859 /* If this register is known to be equal to a constant, record that
2860 it is always equivalent to the constant. */
2861 if (DF_REG_DEF_COUNT (regno) == 1
2862 && note && ! rtx_varies_p (XEXP (note, 0), 0))
2864 rtx note_value = XEXP (note, 0);
2865 remove_note (insn, note);
2866 set_unique_reg_note (insn, REG_EQUIV, note_value);
2869 /* If this insn introduces a "constant" register, decrease the priority
2870 of that register. Record this insn if the register is only used once
2871 more and the equivalence value is the same as our source.
2873 The latter condition is checked for two reasons: First, it is an
2874 indication that it may be more efficient to actually emit the insn
2875 as written (if no registers are available, reload will substitute
2876 the equivalence). Secondly, it avoids problems with any registers
2877 dying in this insn whose death notes would be missed.
2879 If we don't have a REG_EQUIV note, see if this insn is loading
2880 a register used only in one basic block from a MEM. If so, and the
2881 MEM remains unchanged for the life of the register, add a REG_EQUIV
2882 note. */
2884 note = find_reg_note (insn, REG_EQUIV, NULL_RTX);
2886 if (note == 0 && REG_BASIC_BLOCK (regno) >= NUM_FIXED_BLOCKS
2887 && MEM_P (SET_SRC (set))
2888 && validate_equiv_mem (insn, dest, SET_SRC (set)))
2889 note = set_unique_reg_note (insn, REG_EQUIV, copy_rtx (SET_SRC (set)));
2891 if (note)
2893 int regno = REGNO (dest);
2894 rtx x = XEXP (note, 0);
2896 /* If we haven't done so, record for reload that this is an
2897 equivalencing insn. */
2898 if (!reg_equiv[regno].is_arg_equivalence)
2899 reg_equiv_init (regno)
2900 = gen_rtx_INSN_LIST (VOIDmode, insn, reg_equiv_init (regno));
2902 /* Record whether or not we created a REG_EQUIV note for a LABEL_REF.
2903 We might end up substituting the LABEL_REF for uses of the
2904 pseudo here or later. That kind of transformation may turn an
2905 indirect jump into a direct jump, in which case we must rerun the
2906 jump optimizer to ensure that the JUMP_LABEL fields are valid. */
2907 if (GET_CODE (x) == LABEL_REF
2908 || (GET_CODE (x) == CONST
2909 && GET_CODE (XEXP (x, 0)) == PLUS
2910 && (GET_CODE (XEXP (XEXP (x, 0), 0)) == LABEL_REF)))
2911 recorded_label_ref = 1;
2913 reg_equiv[regno].replacement = x;
2914 reg_equiv[regno].src_p = &SET_SRC (set);
2915 reg_equiv[regno].loop_depth = loop_depth;
2917 /* Don't mess with things live during setjmp. */
2918 if (REG_LIVE_LENGTH (regno) >= 0 && optimize)
2920 /* Note that the statement below does not affect the priority
2921 in local-alloc! */
2922 REG_LIVE_LENGTH (regno) *= 2;
2924 /* If the register is referenced exactly twice, meaning it is
2925 set once and used once, indicate that the reference may be
2926 replaced by the equivalence we computed above. Do this
2927 even if the register is only used in one block so that
2928 dependencies can be handled where the last register is
2929 used in a different block (i.e. HIGH / LO_SUM sequences)
2930 and to reduce the number of registers alive across
2931 calls. */
2933 if (REG_N_REFS (regno) == 2
2934 && (rtx_equal_p (x, src)
2935 || ! equiv_init_varies_p (src))
2936 && NONJUMP_INSN_P (insn)
2937 && equiv_init_movable_p (PATTERN (insn), regno))
2938 reg_equiv[regno].replace = 1;
2944 if (!optimize)
2945 goto out;
2947 /* A second pass, to gather additional equivalences with memory. This needs
2948 to be done after we know which registers we are going to replace. */
2950 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2952 rtx set, src, dest;
2953 unsigned regno;
2955 if (! INSN_P (insn))
2956 continue;
2958 set = single_set (insn);
2959 if (! set)
2960 continue;
2962 dest = SET_DEST (set);
2963 src = SET_SRC (set);
2965 /* If this sets a MEM to the contents of a REG that is only used
2966 in a single basic block, see if the register is always equivalent
2967 to that memory location and if moving the store from INSN to the
2968 insn that set REG is safe. If so, put a REG_EQUIV note on the
2969 initializing insn.
2971 Don't add a REG_EQUIV note if the insn already has one. The existing
2972 REG_EQUIV is likely more useful than the one we are adding.
2974 If one of the regs in the address has reg_equiv[REGNO].replace set,
2975 then we can't add this REG_EQUIV note. The reg_equiv[REGNO].replace
2976 optimization may move the set of this register immediately before
2977 insn, which puts it after reg_equiv[REGNO].init_insns, and hence
2978 the mention in the REG_EQUIV note would be to an uninitialized
2979 pseudo. */
2981 if (MEM_P (dest) && REG_P (src)
2982 && (regno = REGNO (src)) >= FIRST_PSEUDO_REGISTER
2983 && REG_BASIC_BLOCK (regno) >= NUM_FIXED_BLOCKS
2984 && DF_REG_DEF_COUNT (regno) == 1
2985 && reg_equiv[regno].init_insns != 0
2986 && reg_equiv[regno].init_insns != const0_rtx
2987 && ! find_reg_note (XEXP (reg_equiv[regno].init_insns, 0),
2988 REG_EQUIV, NULL_RTX)
2989 && ! contains_replace_regs (XEXP (dest, 0)))
2991 rtx init_insn = XEXP (reg_equiv[regno].init_insns, 0);
2992 if (validate_equiv_mem (init_insn, src, dest)
2993 && ! memref_used_between_p (dest, init_insn, insn)
2994 /* Attaching a REG_EQUIV note will fail if INIT_INSN has
2995 multiple sets. */
2996 && set_unique_reg_note (init_insn, REG_EQUIV, copy_rtx (dest)))
2998 /* This insn makes the equivalence, not the one initializing
2999 the register. */
3000 reg_equiv_init (regno)
3001 = gen_rtx_INSN_LIST (VOIDmode, insn, NULL_RTX);
3002 df_notes_rescan (init_insn);
3007 cleared_regs = BITMAP_ALLOC (NULL);
3008 /* Now scan all regs killed in an insn to see if any of them are
3009 registers only used that once. If so, see if we can replace the
3010 reference with the equivalent form. If we can, delete the
3011 initializing reference and this register will go away. If we
3012 can't replace the reference, and the initializing reference is
3013 within the same loop (or in an inner loop), then move the register
3014 initialization just before the use, so that they are in the same
3015 basic block. */
3016 FOR_EACH_BB_REVERSE (bb)
3018 loop_depth = bb->loop_depth;
3019 for (insn = BB_END (bb);
3020 insn != PREV_INSN (BB_HEAD (bb));
3021 insn = PREV_INSN (insn))
3023 rtx link;
3025 if (! INSN_P (insn))
3026 continue;
3028 /* Don't substitute into a non-local goto, this confuses CFG. */
3029 if (JUMP_P (insn)
3030 && find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX))
3031 continue;
3033 for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
3035 if (REG_NOTE_KIND (link) == REG_DEAD
3036 /* Make sure this insn still refers to the register. */
3037 && reg_mentioned_p (XEXP (link, 0), PATTERN (insn)))
3039 int regno = REGNO (XEXP (link, 0));
3040 rtx equiv_insn;
3042 if (! reg_equiv[regno].replace
3043 || reg_equiv[regno].loop_depth < loop_depth
3044 /* There is no sense to move insns if we did
3045 register pressure-sensitive scheduling was
3046 done because it will not improve allocation
3047 but worsen insn schedule with a big
3048 probability. */
3049 || (flag_sched_pressure && flag_schedule_insns))
3050 continue;
3052 /* reg_equiv[REGNO].replace gets set only when
3053 REG_N_REFS[REGNO] is 2, i.e. the register is set
3054 once and used once. (If it were only set, but not used,
3055 flow would have deleted the setting insns.) Hence
3056 there can only be one insn in reg_equiv[REGNO].init_insns. */
3057 gcc_assert (reg_equiv[regno].init_insns
3058 && !XEXP (reg_equiv[regno].init_insns, 1));
3059 equiv_insn = XEXP (reg_equiv[regno].init_insns, 0);
3061 /* We may not move instructions that can throw, since
3062 that changes basic block boundaries and we are not
3063 prepared to adjust the CFG to match. */
3064 if (can_throw_internal (equiv_insn))
3065 continue;
3067 if (asm_noperands (PATTERN (equiv_insn)) < 0
3068 && validate_replace_rtx (regno_reg_rtx[regno],
3069 *(reg_equiv[regno].src_p), insn))
3071 rtx equiv_link;
3072 rtx last_link;
3073 rtx note;
3075 /* Find the last note. */
3076 for (last_link = link; XEXP (last_link, 1);
3077 last_link = XEXP (last_link, 1))
3080 /* Append the REG_DEAD notes from equiv_insn. */
3081 equiv_link = REG_NOTES (equiv_insn);
3082 while (equiv_link)
3084 note = equiv_link;
3085 equiv_link = XEXP (equiv_link, 1);
3086 if (REG_NOTE_KIND (note) == REG_DEAD)
3088 remove_note (equiv_insn, note);
3089 XEXP (last_link, 1) = note;
3090 XEXP (note, 1) = NULL_RTX;
3091 last_link = note;
3095 remove_death (regno, insn);
3096 SET_REG_N_REFS (regno, 0);
3097 REG_FREQ (regno) = 0;
3098 delete_insn (equiv_insn);
3100 reg_equiv[regno].init_insns
3101 = XEXP (reg_equiv[regno].init_insns, 1);
3103 reg_equiv_init (regno) = NULL_RTX;
3104 bitmap_set_bit (cleared_regs, regno);
3106 /* Move the initialization of the register to just before
3107 INSN. Update the flow information. */
3108 else if (prev_nondebug_insn (insn) != equiv_insn)
3110 rtx new_insn;
3112 new_insn = emit_insn_before (PATTERN (equiv_insn), insn);
3113 REG_NOTES (new_insn) = REG_NOTES (equiv_insn);
3114 REG_NOTES (equiv_insn) = 0;
3115 /* Rescan it to process the notes. */
3116 df_insn_rescan (new_insn);
3118 /* Make sure this insn is recognized before
3119 reload begins, otherwise
3120 eliminate_regs_in_insn will die. */
3121 INSN_CODE (new_insn) = INSN_CODE (equiv_insn);
3123 delete_insn (equiv_insn);
3125 XEXP (reg_equiv[regno].init_insns, 0) = new_insn;
3127 REG_BASIC_BLOCK (regno) = bb->index;
3128 REG_N_CALLS_CROSSED (regno) = 0;
3129 REG_FREQ_CALLS_CROSSED (regno) = 0;
3130 REG_N_THROWING_CALLS_CROSSED (regno) = 0;
3131 REG_LIVE_LENGTH (regno) = 2;
3133 if (insn == BB_HEAD (bb))
3134 BB_HEAD (bb) = PREV_INSN (insn);
3136 reg_equiv_init (regno)
3137 = gen_rtx_INSN_LIST (VOIDmode, new_insn, NULL_RTX);
3138 bitmap_set_bit (cleared_regs, regno);
3145 if (!bitmap_empty_p (cleared_regs))
3147 FOR_EACH_BB (bb)
3149 bitmap_and_compl_into (DF_LIVE_IN (bb), cleared_regs);
3150 bitmap_and_compl_into (DF_LIVE_OUT (bb), cleared_regs);
3151 bitmap_and_compl_into (DF_LR_IN (bb), cleared_regs);
3152 bitmap_and_compl_into (DF_LR_OUT (bb), cleared_regs);
3155 /* Last pass - adjust debug insns referencing cleared regs. */
3156 if (MAY_HAVE_DEBUG_INSNS)
3157 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
3158 if (DEBUG_INSN_P (insn))
3160 rtx old_loc = INSN_VAR_LOCATION_LOC (insn);
3161 INSN_VAR_LOCATION_LOC (insn)
3162 = simplify_replace_fn_rtx (old_loc, NULL_RTX,
3163 adjust_cleared_regs,
3164 (void *) cleared_regs);
3165 if (old_loc != INSN_VAR_LOCATION_LOC (insn))
3166 df_insn_rescan (insn);
3170 BITMAP_FREE (cleared_regs);
3172 out:
3173 /* Clean up. */
3175 end_alias_analysis ();
3176 free (reg_equiv);
3177 return recorded_label_ref;
3182 /* Print chain C to FILE. */
3183 static void
3184 print_insn_chain (FILE *file, struct insn_chain *c)
3186 fprintf (file, "insn=%d, ", INSN_UID(c->insn));
3187 bitmap_print (file, &c->live_throughout, "live_throughout: ", ", ");
3188 bitmap_print (file, &c->dead_or_set, "dead_or_set: ", "\n");
3192 /* Print all reload_insn_chains to FILE. */
3193 static void
3194 print_insn_chains (FILE *file)
3196 struct insn_chain *c;
3197 for (c = reload_insn_chain; c ; c = c->next)
3198 print_insn_chain (file, c);
3201 /* Return true if pseudo REGNO should be added to set live_throughout
3202 or dead_or_set of the insn chains for reload consideration. */
3203 static bool
3204 pseudo_for_reload_consideration_p (int regno)
3206 /* Consider spilled pseudos too for IRA because they still have a
3207 chance to get hard-registers in the reload when IRA is used. */
3208 return (reg_renumber[regno] >= 0 || ira_conflicts_p);
3211 /* Init LIVE_SUBREGS[ALLOCNUM] and LIVE_SUBREGS_USED[ALLOCNUM] using
3212 REG to the number of nregs, and INIT_VALUE to get the
3213 initialization. ALLOCNUM need not be the regno of REG. */
3214 static void
3215 init_live_subregs (bool init_value, sbitmap *live_subregs,
3216 int *live_subregs_used, int allocnum, rtx reg)
3218 unsigned int regno = REGNO (SUBREG_REG (reg));
3219 int size = GET_MODE_SIZE (GET_MODE (regno_reg_rtx[regno]));
3221 gcc_assert (size > 0);
3223 /* Been there, done that. */
3224 if (live_subregs_used[allocnum])
3225 return;
3227 /* Create a new one with zeros. */
3228 if (live_subregs[allocnum] == NULL)
3229 live_subregs[allocnum] = sbitmap_alloc (size);
3231 /* If the entire reg was live before blasting into subregs, we need
3232 to init all of the subregs to ones else init to 0. */
3233 if (init_value)
3234 sbitmap_ones (live_subregs[allocnum]);
3235 else
3236 sbitmap_zero (live_subregs[allocnum]);
3238 /* Set the number of bits that we really want. */
3239 live_subregs_used[allocnum] = size;
3242 /* Walk the insns of the current function and build reload_insn_chain,
3243 and record register life information. */
3244 static void
3245 build_insn_chain (void)
3247 unsigned int i;
3248 struct insn_chain **p = &reload_insn_chain;
3249 basic_block bb;
3250 struct insn_chain *c = NULL;
3251 struct insn_chain *next = NULL;
3252 bitmap live_relevant_regs = BITMAP_ALLOC (NULL);
3253 bitmap elim_regset = BITMAP_ALLOC (NULL);
3254 /* live_subregs is a vector used to keep accurate information about
3255 which hardregs are live in multiword pseudos. live_subregs and
3256 live_subregs_used are indexed by pseudo number. The live_subreg
3257 entry for a particular pseudo is only used if the corresponding
3258 element is non zero in live_subregs_used. The value in
3259 live_subregs_used is number of bytes that the pseudo can
3260 occupy. */
3261 sbitmap *live_subregs = XCNEWVEC (sbitmap, max_regno);
3262 int *live_subregs_used = XNEWVEC (int, max_regno);
3264 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3265 if (TEST_HARD_REG_BIT (eliminable_regset, i))
3266 bitmap_set_bit (elim_regset, i);
3267 FOR_EACH_BB_REVERSE (bb)
3269 bitmap_iterator bi;
3270 rtx insn;
3272 CLEAR_REG_SET (live_relevant_regs);
3273 memset (live_subregs_used, 0, max_regno * sizeof (int));
3275 EXECUTE_IF_SET_IN_BITMAP (DF_LR_OUT (bb), 0, i, bi)
3277 if (i >= FIRST_PSEUDO_REGISTER)
3278 break;
3279 bitmap_set_bit (live_relevant_regs, i);
3282 EXECUTE_IF_SET_IN_BITMAP (DF_LR_OUT (bb),
3283 FIRST_PSEUDO_REGISTER, i, bi)
3285 if (pseudo_for_reload_consideration_p (i))
3286 bitmap_set_bit (live_relevant_regs, i);
3289 FOR_BB_INSNS_REVERSE (bb, insn)
3291 if (!NOTE_P (insn) && !BARRIER_P (insn))
3293 unsigned int uid = INSN_UID (insn);
3294 df_ref *def_rec;
3295 df_ref *use_rec;
3297 c = new_insn_chain ();
3298 c->next = next;
3299 next = c;
3300 *p = c;
3301 p = &c->prev;
3303 c->insn = insn;
3304 c->block = bb->index;
3306 if (INSN_P (insn))
3307 for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
3309 df_ref def = *def_rec;
3310 unsigned int regno = DF_REF_REGNO (def);
3312 /* Ignore may clobbers because these are generated
3313 from calls. However, every other kind of def is
3314 added to dead_or_set. */
3315 if (!DF_REF_FLAGS_IS_SET (def, DF_REF_MAY_CLOBBER))
3317 if (regno < FIRST_PSEUDO_REGISTER)
3319 if (!fixed_regs[regno])
3320 bitmap_set_bit (&c->dead_or_set, regno);
3322 else if (pseudo_for_reload_consideration_p (regno))
3323 bitmap_set_bit (&c->dead_or_set, regno);
3326 if ((regno < FIRST_PSEUDO_REGISTER
3327 || reg_renumber[regno] >= 0
3328 || ira_conflicts_p)
3329 && (!DF_REF_FLAGS_IS_SET (def, DF_REF_CONDITIONAL)))
3331 rtx reg = DF_REF_REG (def);
3333 /* We can model subregs, but not if they are
3334 wrapped in ZERO_EXTRACTS. */
3335 if (GET_CODE (reg) == SUBREG
3336 && !DF_REF_FLAGS_IS_SET (def, DF_REF_ZERO_EXTRACT))
3338 unsigned int start = SUBREG_BYTE (reg);
3339 unsigned int last = start
3340 + GET_MODE_SIZE (GET_MODE (reg));
3342 init_live_subregs
3343 (bitmap_bit_p (live_relevant_regs, regno),
3344 live_subregs, live_subregs_used, regno, reg);
3346 if (!DF_REF_FLAGS_IS_SET
3347 (def, DF_REF_STRICT_LOW_PART))
3349 /* Expand the range to cover entire words.
3350 Bytes added here are "don't care". */
3351 start
3352 = start / UNITS_PER_WORD * UNITS_PER_WORD;
3353 last = ((last + UNITS_PER_WORD - 1)
3354 / UNITS_PER_WORD * UNITS_PER_WORD);
3357 /* Ignore the paradoxical bits. */
3358 if ((int)last > live_subregs_used[regno])
3359 last = live_subregs_used[regno];
3361 while (start < last)
3363 RESET_BIT (live_subregs[regno], start);
3364 start++;
3367 if (sbitmap_empty_p (live_subregs[regno]))
3369 live_subregs_used[regno] = 0;
3370 bitmap_clear_bit (live_relevant_regs, regno);
3372 else
3373 /* Set live_relevant_regs here because
3374 that bit has to be true to get us to
3375 look at the live_subregs fields. */
3376 bitmap_set_bit (live_relevant_regs, regno);
3378 else
3380 /* DF_REF_PARTIAL is generated for
3381 subregs, STRICT_LOW_PART, and
3382 ZERO_EXTRACT. We handle the subreg
3383 case above so here we have to keep from
3384 modeling the def as a killing def. */
3385 if (!DF_REF_FLAGS_IS_SET (def, DF_REF_PARTIAL))
3387 bitmap_clear_bit (live_relevant_regs, regno);
3388 live_subregs_used[regno] = 0;
3394 bitmap_and_compl_into (live_relevant_regs, elim_regset);
3395 bitmap_copy (&c->live_throughout, live_relevant_regs);
3397 if (INSN_P (insn))
3398 for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
3400 df_ref use = *use_rec;
3401 unsigned int regno = DF_REF_REGNO (use);
3402 rtx reg = DF_REF_REG (use);
3404 /* DF_REF_READ_WRITE on a use means that this use
3405 is fabricated from a def that is a partial set
3406 to a multiword reg. Here, we only model the
3407 subreg case that is not wrapped in ZERO_EXTRACT
3408 precisely so we do not need to look at the
3409 fabricated use. */
3410 if (DF_REF_FLAGS_IS_SET (use, DF_REF_READ_WRITE)
3411 && !DF_REF_FLAGS_IS_SET (use, DF_REF_ZERO_EXTRACT)
3412 && DF_REF_FLAGS_IS_SET (use, DF_REF_SUBREG))
3413 continue;
3415 /* Add the last use of each var to dead_or_set. */
3416 if (!bitmap_bit_p (live_relevant_regs, regno))
3418 if (regno < FIRST_PSEUDO_REGISTER)
3420 if (!fixed_regs[regno])
3421 bitmap_set_bit (&c->dead_or_set, regno);
3423 else if (pseudo_for_reload_consideration_p (regno))
3424 bitmap_set_bit (&c->dead_or_set, regno);
3427 if (regno < FIRST_PSEUDO_REGISTER
3428 || pseudo_for_reload_consideration_p (regno))
3430 if (GET_CODE (reg) == SUBREG
3431 && !DF_REF_FLAGS_IS_SET (use,
3432 DF_REF_SIGN_EXTRACT
3433 | DF_REF_ZERO_EXTRACT))
3435 unsigned int start = SUBREG_BYTE (reg);
3436 unsigned int last = start
3437 + GET_MODE_SIZE (GET_MODE (reg));
3439 init_live_subregs
3440 (bitmap_bit_p (live_relevant_regs, regno),
3441 live_subregs, live_subregs_used, regno, reg);
3443 /* Ignore the paradoxical bits. */
3444 if ((int)last > live_subregs_used[regno])
3445 last = live_subregs_used[regno];
3447 while (start < last)
3449 SET_BIT (live_subregs[regno], start);
3450 start++;
3453 else
3454 /* Resetting the live_subregs_used is
3455 effectively saying do not use the subregs
3456 because we are reading the whole
3457 pseudo. */
3458 live_subregs_used[regno] = 0;
3459 bitmap_set_bit (live_relevant_regs, regno);
3465 /* FIXME!! The following code is a disaster. Reload needs to see the
3466 labels and jump tables that are just hanging out in between
3467 the basic blocks. See pr33676. */
3468 insn = BB_HEAD (bb);
3470 /* Skip over the barriers and cruft. */
3471 while (insn && (BARRIER_P (insn) || NOTE_P (insn)
3472 || BLOCK_FOR_INSN (insn) == bb))
3473 insn = PREV_INSN (insn);
3475 /* While we add anything except barriers and notes, the focus is
3476 to get the labels and jump tables into the
3477 reload_insn_chain. */
3478 while (insn)
3480 if (!NOTE_P (insn) && !BARRIER_P (insn))
3482 if (BLOCK_FOR_INSN (insn))
3483 break;
3485 c = new_insn_chain ();
3486 c->next = next;
3487 next = c;
3488 *p = c;
3489 p = &c->prev;
3491 /* The block makes no sense here, but it is what the old
3492 code did. */
3493 c->block = bb->index;
3494 c->insn = insn;
3495 bitmap_copy (&c->live_throughout, live_relevant_regs);
3497 insn = PREV_INSN (insn);
3501 for (i = 0; i < (unsigned int) max_regno; i++)
3502 free (live_subregs[i]);
3504 reload_insn_chain = c;
3505 *p = NULL;
3507 free (live_subregs);
3508 free (live_subregs_used);
3509 BITMAP_FREE (live_relevant_regs);
3510 BITMAP_FREE (elim_regset);
3512 if (dump_file)
3513 print_insn_chains (dump_file);
3518 /* All natural loops. */
3519 struct loops ira_loops;
3521 /* True if we have allocno conflicts. It is false for non-optimized
3522 mode or when the conflict table is too big. */
3523 bool ira_conflicts_p;
3525 /* Saved between IRA and reload. */
3526 static int saved_flag_ira_share_spill_slots;
3528 /* This is the main entry of IRA. */
3529 static void
3530 ira (FILE *f)
3532 int allocated_reg_info_size;
3533 bool loops_p;
3534 int max_regno_before_ira, ira_max_point_before_emit;
3535 int rebuild_p;
3537 if (flag_caller_saves)
3538 init_caller_save ();
3540 if (flag_ira_verbose < 10)
3542 internal_flag_ira_verbose = flag_ira_verbose;
3543 ira_dump_file = f;
3545 else
3547 internal_flag_ira_verbose = flag_ira_verbose - 10;
3548 ira_dump_file = stderr;
3551 ira_conflicts_p = optimize > 0;
3552 setup_prohibited_mode_move_regs ();
3554 df_note_add_problem ();
3556 if (optimize == 1)
3558 df_live_add_problem ();
3559 df_live_set_all_dirty ();
3561 #ifdef ENABLE_CHECKING
3562 df->changeable_flags |= DF_VERIFY_SCHEDULED;
3563 #endif
3564 df_analyze ();
3565 df_clear_flags (DF_NO_INSN_RESCAN);
3566 regstat_init_n_sets_and_refs ();
3567 regstat_compute_ri ();
3569 /* If we are not optimizing, then this is the only place before
3570 register allocation where dataflow is done. And that is needed
3571 to generate these warnings. */
3572 if (warn_clobbered)
3573 generate_setjmp_warnings ();
3575 /* Determine if the current function is a leaf before running IRA
3576 since this can impact optimizations done by the prologue and
3577 epilogue thus changing register elimination offsets. */
3578 current_function_is_leaf = leaf_function_p ();
3580 if (resize_reg_info () && flag_ira_loop_pressure)
3581 ira_set_pseudo_classes (ira_dump_file);
3583 rebuild_p = update_equiv_regs ();
3585 #ifndef IRA_NO_OBSTACK
3586 gcc_obstack_init (&ira_obstack);
3587 #endif
3588 bitmap_obstack_initialize (&ira_bitmap_obstack);
3589 if (optimize)
3591 max_regno = max_reg_num ();
3592 ira_reg_equiv_len = max_regno;
3593 ira_reg_equiv_invariant_p
3594 = (bool *) ira_allocate (max_regno * sizeof (bool));
3595 memset (ira_reg_equiv_invariant_p, 0, max_regno * sizeof (bool));
3596 ira_reg_equiv_const = (rtx *) ira_allocate (max_regno * sizeof (rtx));
3597 memset (ira_reg_equiv_const, 0, max_regno * sizeof (rtx));
3598 find_reg_equiv_invariant_const ();
3599 if (rebuild_p)
3601 timevar_push (TV_JUMP);
3602 rebuild_jump_labels (get_insns ());
3603 if (purge_all_dead_edges ())
3604 delete_unreachable_blocks ();
3605 timevar_pop (TV_JUMP);
3609 max_regno_before_ira = allocated_reg_info_size = max_reg_num ();
3610 ira_setup_eliminable_regset ();
3612 ira_overall_cost = ira_reg_cost = ira_mem_cost = 0;
3613 ira_load_cost = ira_store_cost = ira_shuffle_cost = 0;
3614 ira_move_loops_num = ira_additional_jumps_num = 0;
3616 ira_assert (current_loops == NULL);
3617 if (flag_ira_region == IRA_REGION_ALL || flag_ira_region == IRA_REGION_MIXED)
3619 flow_loops_find (&ira_loops);
3620 record_loop_exits ();
3621 current_loops = &ira_loops;
3624 if (internal_flag_ira_verbose > 0 && ira_dump_file != NULL)
3625 fprintf (ira_dump_file, "Building IRA IR\n");
3626 loops_p = ira_build ();
3628 ira_assert (ira_conflicts_p || !loops_p);
3630 saved_flag_ira_share_spill_slots = flag_ira_share_spill_slots;
3631 if (too_high_register_pressure_p () || cfun->calls_setjmp)
3632 /* It is just wasting compiler's time to pack spilled pseudos into
3633 stack slots in this case -- prohibit it. We also do this if
3634 there is setjmp call because a variable not modified between
3635 setjmp and longjmp the compiler is required to preserve its
3636 value and sharing slots does not guarantee it. */
3637 flag_ira_share_spill_slots = FALSE;
3639 ira_color ();
3641 ira_max_point_before_emit = ira_max_point;
3643 ira_initiate_emit_data ();
3645 ira_emit (loops_p);
3647 if (ira_conflicts_p)
3649 max_regno = max_reg_num ();
3651 if (! loops_p)
3652 ira_initiate_assign ();
3653 else
3655 expand_reg_info (allocated_reg_info_size);
3656 setup_preferred_alternate_classes_for_new_pseudos
3657 (allocated_reg_info_size);
3658 allocated_reg_info_size = max_regno;
3660 if (internal_flag_ira_verbose > 0 && ira_dump_file != NULL)
3661 fprintf (ira_dump_file, "Flattening IR\n");
3662 ira_flattening (max_regno_before_ira, ira_max_point_before_emit);
3663 /* New insns were generated: add notes and recalculate live
3664 info. */
3665 df_analyze ();
3667 flow_loops_find (&ira_loops);
3668 record_loop_exits ();
3669 current_loops = &ira_loops;
3671 setup_allocno_assignment_flags ();
3672 ira_initiate_assign ();
3673 ira_reassign_conflict_allocnos (max_regno);
3677 ira_finish_emit_data ();
3679 setup_reg_renumber ();
3681 calculate_allocation_cost ();
3683 #ifdef ENABLE_IRA_CHECKING
3684 if (ira_conflicts_p)
3685 check_allocation ();
3686 #endif
3688 if (delete_trivially_dead_insns (get_insns (), max_reg_num ()))
3689 df_analyze ();
3691 if (max_regno != max_regno_before_ira)
3693 regstat_free_n_sets_and_refs ();
3694 regstat_free_ri ();
3695 regstat_init_n_sets_and_refs ();
3696 regstat_compute_ri ();
3699 overall_cost_before = ira_overall_cost;
3700 if (! ira_conflicts_p)
3701 grow_reg_equivs ();
3702 else
3704 fix_reg_equiv_init ();
3706 #ifdef ENABLE_IRA_CHECKING
3707 print_redundant_copies ();
3708 #endif
3710 ira_spilled_reg_stack_slots_num = 0;
3711 ira_spilled_reg_stack_slots
3712 = ((struct ira_spilled_reg_stack_slot *)
3713 ira_allocate (max_regno
3714 * sizeof (struct ira_spilled_reg_stack_slot)));
3715 memset (ira_spilled_reg_stack_slots, 0,
3716 max_regno * sizeof (struct ira_spilled_reg_stack_slot));
3718 allocate_initial_values (reg_equivs);
3721 static void
3722 do_reload (void)
3724 basic_block bb;
3725 bool need_dce;
3727 if (flag_ira_verbose < 10)
3728 ira_dump_file = dump_file;
3730 df_set_flags (DF_NO_INSN_RESCAN);
3731 build_insn_chain ();
3733 need_dce = reload (get_insns (), ira_conflicts_p);
3735 timevar_push (TV_IRA);
3737 if (ira_conflicts_p)
3739 ira_free (ira_spilled_reg_stack_slots);
3741 ira_finish_assign ();
3743 if (internal_flag_ira_verbose > 0 && ira_dump_file != NULL
3744 && overall_cost_before != ira_overall_cost)
3745 fprintf (ira_dump_file, "+++Overall after reload %d\n", ira_overall_cost);
3746 ira_destroy ();
3748 flag_ira_share_spill_slots = saved_flag_ira_share_spill_slots;
3750 if (current_loops != NULL)
3752 flow_loops_free (&ira_loops);
3753 free_dominance_info (CDI_DOMINATORS);
3755 FOR_ALL_BB (bb)
3756 bb->loop_father = NULL;
3757 current_loops = NULL;
3759 regstat_free_ri ();
3760 regstat_free_n_sets_and_refs ();
3762 if (optimize)
3764 cleanup_cfg (CLEANUP_EXPENSIVE);
3766 ira_free (ira_reg_equiv_invariant_p);
3767 ira_free (ira_reg_equiv_const);
3770 bitmap_obstack_release (&ira_bitmap_obstack);
3771 #ifndef IRA_NO_OBSTACK
3772 obstack_free (&ira_obstack, NULL);
3773 #endif
3775 /* The code after the reload has changed so much that at this point
3776 we might as well just rescan everything. Note that
3777 df_rescan_all_insns is not going to help here because it does not
3778 touch the artificial uses and defs. */
3779 df_finish_pass (true);
3780 if (optimize > 1)
3781 df_live_add_problem ();
3782 df_scan_alloc (NULL);
3783 df_scan_blocks ();
3785 if (optimize)
3786 df_analyze ();
3788 if (need_dce && optimize)
3789 run_fast_dce ();
3791 timevar_pop (TV_IRA);
3794 /* Run the integrated register allocator. */
3795 static unsigned int
3796 rest_of_handle_ira (void)
3798 ira (dump_file);
3799 return 0;
3802 struct rtl_opt_pass pass_ira =
3805 RTL_PASS,
3806 "ira", /* name */
3807 NULL, /* gate */
3808 rest_of_handle_ira, /* execute */
3809 NULL, /* sub */
3810 NULL, /* next */
3811 0, /* static_pass_number */
3812 TV_IRA, /* tv_id */
3813 0, /* properties_required */
3814 0, /* properties_provided */
3815 0, /* properties_destroyed */
3816 0, /* todo_flags_start */
3817 TODO_dump_func /* todo_flags_finish */
3821 static unsigned int
3822 rest_of_handle_reload (void)
3824 do_reload ();
3825 return 0;
3828 struct rtl_opt_pass pass_reload =
3831 RTL_PASS,
3832 "reload", /* name */
3833 NULL, /* gate */
3834 rest_of_handle_reload, /* execute */
3835 NULL, /* sub */
3836 NULL, /* next */
3837 0, /* static_pass_number */
3838 TV_RELOAD, /* tv_id */
3839 0, /* properties_required */
3840 0, /* properties_provided */
3841 0, /* properties_destroyed */
3842 0, /* todo_flags_start */
3843 TODO_dump_func | TODO_ggc_collect /* todo_flags_finish */