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Commit | Line | Data |
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531b10fc SB |
1 | /* Lower GIMPLE_SWITCH expressions to something more efficient than |
2 | a jump table. | |
cbe34bb5 | 3 | Copyright (C) 2006-2017 Free Software Foundation, Inc. |
b6e99746 MJ |
4 | |
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it | |
8 | under the terms of the GNU General Public License as published by the | |
9 | Free Software Foundation; either version 3, or (at your option) any | |
10 | later version. | |
11 | ||
12 | GCC is distributed in the hope that it will be useful, but WITHOUT | |
13 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GCC; see the file COPYING3. If not, write to the Free | |
19 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA | |
20 | 02110-1301, USA. */ | |
21 | ||
531b10fc SB |
22 | /* This file handles the lowering of GIMPLE_SWITCH to an indexed |
23 | load, or a series of bit-test-and-branch expressions. */ | |
24 | ||
25 | #include "config.h" | |
26 | #include "system.h" | |
27 | #include "coretypes.h" | |
c7131fb2 | 28 | #include "backend.h" |
957060b5 AM |
29 | #include "insn-codes.h" |
30 | #include "rtl.h" | |
c7131fb2 AM |
31 | #include "tree.h" |
32 | #include "gimple.h" | |
957060b5 AM |
33 | #include "cfghooks.h" |
34 | #include "tree-pass.h" | |
c7131fb2 | 35 | #include "ssa.h" |
957060b5 AM |
36 | #include "optabs-tree.h" |
37 | #include "cgraph.h" | |
38 | #include "gimple-pretty-print.h" | |
531b10fc | 39 | #include "params.h" |
40e23961 | 40 | #include "fold-const.h" |
d8a2d370 DN |
41 | #include "varasm.h" |
42 | #include "stor-layout.h" | |
60393bbc | 43 | #include "cfganal.h" |
45b0be94 | 44 | #include "gimplify.h" |
5be5c238 | 45 | #include "gimple-iterator.h" |
18f429e2 | 46 | #include "gimplify-me.h" |
442b4905 | 47 | #include "tree-cfg.h" |
a9e0d843 | 48 | #include "cfgloop.h" |
9dc3d6a9 ML |
49 | #include "alloc-pool.h" |
50 | #include "target.h" | |
51 | #include "tree-into-ssa.h" | |
7ee2468b SB |
52 | |
53 | /* ??? For lang_hooks.types.type_for_mode, but is there a word_mode | |
54 | type in the GIMPLE type system that is language-independent? */ | |
531b10fc SB |
55 | #include "langhooks.h" |
56 | ||
531b10fc SB |
57 | \f |
58 | /* Maximum number of case bit tests. | |
59 | FIXME: This should be derived from PARAM_CASE_VALUES_THRESHOLD and | |
60 | targetm.case_values_threshold(), or be its own param. */ | |
61 | #define MAX_CASE_BIT_TESTS 3 | |
62 | ||
63 | /* Split the basic block at the statement pointed to by GSIP, and insert | |
64 | a branch to the target basic block of E_TRUE conditional on tree | |
65 | expression COND. | |
66 | ||
67 | It is assumed that there is already an edge from the to-be-split | |
68 | basic block to E_TRUE->dest block. This edge is removed, and the | |
69 | profile information on the edge is re-used for the new conditional | |
70 | jump. | |
71 | ||
72 | The CFG is updated. The dominator tree will not be valid after | |
73 | this transformation, but the immediate dominators are updated if | |
74 | UPDATE_DOMINATORS is true. | |
75 | ||
76 | Returns the newly created basic block. */ | |
77 | ||
78 | static basic_block | |
79 | hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip, | |
80 | tree cond, edge e_true, | |
81 | bool update_dominators) | |
82 | { | |
83 | tree tmp; | |
538dd0b7 | 84 | gcond *cond_stmt; |
531b10fc SB |
85 | edge e_false; |
86 | basic_block new_bb, split_bb = gsi_bb (*gsip); | |
87 | bool dominated_e_true = false; | |
88 | ||
89 | gcc_assert (e_true->src == split_bb); | |
90 | ||
91 | if (update_dominators | |
92 | && get_immediate_dominator (CDI_DOMINATORS, e_true->dest) == split_bb) | |
93 | dominated_e_true = true; | |
94 | ||
95 | tmp = force_gimple_operand_gsi (gsip, cond, /*simple=*/true, NULL, | |
96 | /*before=*/true, GSI_SAME_STMT); | |
97 | cond_stmt = gimple_build_cond_from_tree (tmp, NULL_TREE, NULL_TREE); | |
98 | gsi_insert_before (gsip, cond_stmt, GSI_SAME_STMT); | |
99 | ||
100 | e_false = split_block (split_bb, cond_stmt); | |
101 | new_bb = e_false->dest; | |
102 | redirect_edge_pred (e_true, split_bb); | |
103 | ||
104 | e_true->flags &= ~EDGE_FALLTHRU; | |
105 | e_true->flags |= EDGE_TRUE_VALUE; | |
106 | ||
107 | e_false->flags &= ~EDGE_FALLTHRU; | |
108 | e_false->flags |= EDGE_FALSE_VALUE; | |
357067f2 | 109 | e_false->probability = e_true->probability.invert (); |
ef30ab83 | 110 | new_bb->count = e_false->count (); |
531b10fc SB |
111 | |
112 | if (update_dominators) | |
113 | { | |
114 | if (dominated_e_true) | |
115 | set_immediate_dominator (CDI_DOMINATORS, e_true->dest, split_bb); | |
116 | set_immediate_dominator (CDI_DOMINATORS, e_false->dest, split_bb); | |
117 | } | |
118 | ||
119 | return new_bb; | |
120 | } | |
121 | ||
122 | ||
531b10fc SB |
123 | /* Return true if a switch should be expanded as a bit test. |
124 | RANGE is the difference between highest and lowest case. | |
125 | UNIQ is number of unique case node targets, not counting the default case. | |
126 | COUNT is the number of comparisons needed, not counting the default case. */ | |
127 | ||
128 | static bool | |
129 | expand_switch_using_bit_tests_p (tree range, | |
130 | unsigned int uniq, | |
72798784 | 131 | unsigned int count, bool speed_p) |
531b10fc SB |
132 | { |
133 | return (((uniq == 1 && count >= 3) | |
134 | || (uniq == 2 && count >= 5) | |
135 | || (uniq == 3 && count >= 6)) | |
72798784 | 136 | && lshift_cheap_p (speed_p) |
531b10fc SB |
137 | && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0 |
138 | && compare_tree_int (range, 0) > 0); | |
139 | } | |
140 | \f | |
141 | /* Implement switch statements with bit tests | |
142 | ||
143 | A GIMPLE switch statement can be expanded to a short sequence of bit-wise | |
144 | comparisons. "switch(x)" is converted into "if ((1 << (x-MINVAL)) & CST)" | |
145 | where CST and MINVAL are integer constants. This is better than a series | |
146 | of compare-and-banch insns in some cases, e.g. we can implement: | |
147 | ||
148 | if ((x==4) || (x==6) || (x==9) || (x==11)) | |
149 | ||
150 | as a single bit test: | |
151 | ||
152 | if ((1<<x) & ((1<<4)|(1<<6)|(1<<9)|(1<<11))) | |
153 | ||
154 | This transformation is only applied if the number of case targets is small, | |
34540577 | 155 | if CST constains at least 3 bits, and "1 << x" is cheap. The bit tests are |
531b10fc SB |
156 | performed in "word_mode". |
157 | ||
158 | The following example shows the code the transformation generates: | |
159 | ||
160 | int bar(int x) | |
161 | { | |
162 | switch (x) | |
163 | { | |
164 | case '0': case '1': case '2': case '3': case '4': | |
165 | case '5': case '6': case '7': case '8': case '9': | |
166 | case 'A': case 'B': case 'C': case 'D': case 'E': | |
167 | case 'F': | |
168 | return 1; | |
169 | } | |
170 | return 0; | |
171 | } | |
172 | ||
173 | ==> | |
174 | ||
175 | bar (int x) | |
176 | { | |
177 | tmp1 = x - 48; | |
178 | if (tmp1 > (70 - 48)) goto L2; | |
179 | tmp2 = 1 << tmp1; | |
180 | tmp3 = 0b11111100000001111111111; | |
181 | if ((tmp2 & tmp3) != 0) goto L1 ; else goto L2; | |
182 | L1: | |
183 | return 1; | |
184 | L2: | |
185 | return 0; | |
186 | } | |
187 | ||
188 | TODO: There are still some improvements to this transformation that could | |
189 | be implemented: | |
190 | ||
191 | * A narrower mode than word_mode could be used if that is cheaper, e.g. | |
192 | for x86_64 where a narrower-mode shift may result in smaller code. | |
193 | ||
194 | * The compounded constant could be shifted rather than the one. The | |
195 | test would be either on the sign bit or on the least significant bit, | |
196 | depending on the direction of the shift. On some machines, the test | |
197 | for the branch would be free if the bit to test is already set by the | |
198 | shift operation. | |
199 | ||
200 | This transformation was contributed by Roger Sayle, see this e-mail: | |
201 | http://gcc.gnu.org/ml/gcc-patches/2003-01/msg01950.html | |
202 | */ | |
203 | ||
204 | /* A case_bit_test represents a set of case nodes that may be | |
205 | selected from using a bit-wise comparison. HI and LO hold | |
206 | the integer to be tested against, TARGET_EDGE contains the | |
207 | edge to the basic block to jump to upon success and BITS | |
208 | counts the number of case nodes handled by this test, | |
209 | typically the number of bits set in HI:LO. The LABEL field | |
210 | is used to quickly identify all cases in this set without | |
211 | looking at label_to_block for every case label. */ | |
212 | ||
213 | struct case_bit_test | |
214 | { | |
aa79a1e1 | 215 | wide_int mask; |
531b10fc SB |
216 | edge target_edge; |
217 | tree label; | |
218 | int bits; | |
219 | }; | |
220 | ||
221 | /* Comparison function for qsort to order bit tests by decreasing | |
222 | probability of execution. Our best guess comes from a measured | |
223 | profile. If the profile counts are equal, break even on the | |
224 | number of case nodes, i.e. the node with the most cases gets | |
225 | tested first. | |
226 | ||
227 | TODO: Actually this currently runs before a profile is available. | |
228 | Therefore the case-as-bit-tests transformation should be done | |
229 | later in the pass pipeline, or something along the lines of | |
230 | "Efficient and effective branch reordering using profile data" | |
231 | (Yang et. al., 2002) should be implemented (although, how good | |
232 | is a paper is called "Efficient and effective ..." when the | |
233 | latter is implied by the former, but oh well...). */ | |
234 | ||
235 | static int | |
236 | case_bit_test_cmp (const void *p1, const void *p2) | |
237 | { | |
238 | const struct case_bit_test *const d1 = (const struct case_bit_test *) p1; | |
239 | const struct case_bit_test *const d2 = (const struct case_bit_test *) p2; | |
240 | ||
ef30ab83 | 241 | if (d2->target_edge->count () < d1->target_edge->count ()) |
3995f3a2 | 242 | return -1; |
ef30ab83 | 243 | if (d2->target_edge->count () > d1->target_edge->count ()) |
3995f3a2 | 244 | return 1; |
531b10fc SB |
245 | if (d2->bits != d1->bits) |
246 | return d2->bits - d1->bits; | |
247 | ||
248 | /* Stabilize the sort. */ | |
249 | return LABEL_DECL_UID (d2->label) - LABEL_DECL_UID (d1->label); | |
250 | } | |
251 | ||
252 | /* Expand a switch statement by a short sequence of bit-wise | |
253 | comparisons. "switch(x)" is effectively converted into | |
254 | "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are | |
255 | integer constants. | |
256 | ||
257 | INDEX_EXPR is the value being switched on. | |
258 | ||
259 | MINVAL is the lowest case value of in the case nodes, | |
260 | and RANGE is highest value minus MINVAL. MINVAL and RANGE | |
261 | are not guaranteed to be of the same type as INDEX_EXPR | |
262 | (the gimplifier doesn't change the type of case label values, | |
263 | and MINVAL and RANGE are derived from those values). | |
aa79a1e1 | 264 | MAXVAL is MINVAL + RANGE. |
531b10fc SB |
265 | |
266 | There *MUST* be MAX_CASE_BIT_TESTS or less unique case | |
267 | node targets. */ | |
268 | ||
269 | static void | |
538dd0b7 | 270 | emit_case_bit_tests (gswitch *swtch, tree index_expr, |
aa79a1e1 | 271 | tree minval, tree range, tree maxval) |
531b10fc | 272 | { |
66846c07 | 273 | struct case_bit_test test[MAX_CASE_BIT_TESTS] = { {} }; |
531b10fc SB |
274 | unsigned int i, j, k; |
275 | unsigned int count; | |
276 | ||
277 | basic_block switch_bb = gimple_bb (swtch); | |
278 | basic_block default_bb, new_default_bb, new_bb; | |
279 | edge default_edge; | |
280 | bool update_dom = dom_info_available_p (CDI_DOMINATORS); | |
281 | ||
6e1aa848 | 282 | vec<basic_block> bbs_to_fix_dom = vNULL; |
531b10fc SB |
283 | |
284 | tree index_type = TREE_TYPE (index_expr); | |
285 | tree unsigned_index_type = unsigned_type_for (index_type); | |
286 | unsigned int branch_num = gimple_switch_num_labels (swtch); | |
287 | ||
288 | gimple_stmt_iterator gsi; | |
538dd0b7 | 289 | gassign *shift_stmt; |
531b10fc SB |
290 | |
291 | tree idx, tmp, csui; | |
292 | tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1); | |
293 | tree word_mode_zero = fold_convert (word_type_node, integer_zero_node); | |
294 | tree word_mode_one = fold_convert (word_type_node, integer_one_node); | |
aa79a1e1 JJ |
295 | int prec = TYPE_PRECISION (word_type_node); |
296 | wide_int wone = wi::one (prec); | |
531b10fc | 297 | |
531b10fc | 298 | /* Get the edge for the default case. */ |
fd8d363e | 299 | tmp = gimple_switch_default_label (swtch); |
531b10fc SB |
300 | default_bb = label_to_block (CASE_LABEL (tmp)); |
301 | default_edge = find_edge (switch_bb, default_bb); | |
302 | ||
303 | /* Go through all case labels, and collect the case labels, profile | |
304 | counts, and other information we need to build the branch tests. */ | |
305 | count = 0; | |
306 | for (i = 1; i < branch_num; i++) | |
307 | { | |
308 | unsigned int lo, hi; | |
309 | tree cs = gimple_switch_label (swtch, i); | |
310 | tree label = CASE_LABEL (cs); | |
8166ff4d | 311 | edge e = find_edge (switch_bb, label_to_block (label)); |
531b10fc | 312 | for (k = 0; k < count; k++) |
8166ff4d | 313 | if (e == test[k].target_edge) |
531b10fc SB |
314 | break; |
315 | ||
316 | if (k == count) | |
317 | { | |
531b10fc | 318 | gcc_checking_assert (count < MAX_CASE_BIT_TESTS); |
aa79a1e1 | 319 | test[k].mask = wi::zero (prec); |
531b10fc SB |
320 | test[k].target_edge = e; |
321 | test[k].label = label; | |
322 | test[k].bits = 1; | |
323 | count++; | |
324 | } | |
325 | else | |
326 | test[k].bits++; | |
327 | ||
386b1f1f RS |
328 | lo = tree_to_uhwi (int_const_binop (MINUS_EXPR, |
329 | CASE_LOW (cs), minval)); | |
531b10fc SB |
330 | if (CASE_HIGH (cs) == NULL_TREE) |
331 | hi = lo; | |
332 | else | |
386b1f1f RS |
333 | hi = tree_to_uhwi (int_const_binop (MINUS_EXPR, |
334 | CASE_HIGH (cs), minval)); | |
531b10fc SB |
335 | |
336 | for (j = lo; j <= hi; j++) | |
aa79a1e1 | 337 | test[k].mask |= wi::lshift (wone, j); |
531b10fc SB |
338 | } |
339 | ||
c3284718 | 340 | qsort (test, count, sizeof (*test), case_bit_test_cmp); |
531b10fc | 341 | |
aa79a1e1 JJ |
342 | /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of |
343 | the minval subtractions, but it might make the mask constants more | |
344 | expensive. So, compare the costs. */ | |
345 | if (compare_tree_int (minval, 0) > 0 | |
346 | && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0) | |
347 | { | |
348 | int cost_diff; | |
349 | HOST_WIDE_INT m = tree_to_uhwi (minval); | |
350 | rtx reg = gen_raw_REG (word_mode, 10000); | |
351 | bool speed_p = optimize_bb_for_speed_p (gimple_bb (swtch)); | |
352 | cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg, | |
353 | GEN_INT (-m)), speed_p); | |
354 | for (i = 0; i < count; i++) | |
355 | { | |
356 | rtx r = immed_wide_int_const (test[i].mask, word_mode); | |
e548c9df AM |
357 | cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r), |
358 | word_mode, speed_p); | |
aa79a1e1 | 359 | r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode); |
e548c9df AM |
360 | cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r), |
361 | word_mode, speed_p); | |
aa79a1e1 JJ |
362 | } |
363 | if (cost_diff > 0) | |
364 | { | |
365 | for (i = 0; i < count; i++) | |
366 | test[i].mask = wi::lshift (test[i].mask, m); | |
367 | minval = build_zero_cst (TREE_TYPE (minval)); | |
368 | range = maxval; | |
369 | } | |
370 | } | |
371 | ||
531b10fc SB |
372 | /* We generate two jumps to the default case label. |
373 | Split the default edge, so that we don't have to do any PHI node | |
374 | updating. */ | |
375 | new_default_bb = split_edge (default_edge); | |
376 | ||
377 | if (update_dom) | |
378 | { | |
9771b263 DN |
379 | bbs_to_fix_dom.create (10); |
380 | bbs_to_fix_dom.quick_push (switch_bb); | |
381 | bbs_to_fix_dom.quick_push (default_bb); | |
382 | bbs_to_fix_dom.quick_push (new_default_bb); | |
531b10fc SB |
383 | } |
384 | ||
385 | /* Now build the test-and-branch code. */ | |
386 | ||
387 | gsi = gsi_last_bb (switch_bb); | |
388 | ||
d9e408de TV |
389 | /* idx = (unsigned)x - minval. */ |
390 | idx = fold_convert (unsigned_index_type, index_expr); | |
391 | idx = fold_build2 (MINUS_EXPR, unsigned_index_type, idx, | |
392 | fold_convert (unsigned_index_type, minval)); | |
531b10fc SB |
393 | idx = force_gimple_operand_gsi (&gsi, idx, |
394 | /*simple=*/true, NULL_TREE, | |
395 | /*before=*/true, GSI_SAME_STMT); | |
396 | ||
397 | /* if (idx > range) goto default */ | |
398 | range = force_gimple_operand_gsi (&gsi, | |
399 | fold_convert (unsigned_index_type, range), | |
400 | /*simple=*/true, NULL_TREE, | |
401 | /*before=*/true, GSI_SAME_STMT); | |
402 | tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range); | |
403 | new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, default_edge, update_dom); | |
404 | if (update_dom) | |
9771b263 | 405 | bbs_to_fix_dom.quick_push (new_bb); |
531b10fc SB |
406 | gcc_assert (gimple_bb (swtch) == new_bb); |
407 | gsi = gsi_last_bb (new_bb); | |
408 | ||
409 | /* Any blocks dominated by the GIMPLE_SWITCH, but that are not successors | |
410 | of NEW_BB, are still immediately dominated by SWITCH_BB. Make it so. */ | |
411 | if (update_dom) | |
412 | { | |
9771b263 | 413 | vec<basic_block> dom_bbs; |
531b10fc SB |
414 | basic_block dom_son; |
415 | ||
416 | dom_bbs = get_dominated_by (CDI_DOMINATORS, new_bb); | |
9771b263 | 417 | FOR_EACH_VEC_ELT (dom_bbs, i, dom_son) |
531b10fc SB |
418 | { |
419 | edge e = find_edge (new_bb, dom_son); | |
420 | if (e && single_pred_p (e->dest)) | |
421 | continue; | |
422 | set_immediate_dominator (CDI_DOMINATORS, dom_son, switch_bb); | |
9771b263 | 423 | bbs_to_fix_dom.safe_push (dom_son); |
531b10fc | 424 | } |
9771b263 | 425 | dom_bbs.release (); |
531b10fc SB |
426 | } |
427 | ||
428 | /* csui = (1 << (word_mode) idx) */ | |
b731b390 | 429 | csui = make_ssa_name (word_type_node); |
531b10fc SB |
430 | tmp = fold_build2 (LSHIFT_EXPR, word_type_node, word_mode_one, |
431 | fold_convert (word_type_node, idx)); | |
432 | tmp = force_gimple_operand_gsi (&gsi, tmp, | |
433 | /*simple=*/false, NULL_TREE, | |
434 | /*before=*/true, GSI_SAME_STMT); | |
435 | shift_stmt = gimple_build_assign (csui, tmp); | |
531b10fc SB |
436 | gsi_insert_before (&gsi, shift_stmt, GSI_SAME_STMT); |
437 | update_stmt (shift_stmt); | |
438 | ||
439 | /* for each unique set of cases: | |
440 | if (const & csui) goto target */ | |
441 | for (k = 0; k < count; k++) | |
442 | { | |
aa79a1e1 | 443 | tmp = wide_int_to_tree (word_type_node, test[k].mask); |
531b10fc SB |
444 | tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp); |
445 | tmp = force_gimple_operand_gsi (&gsi, tmp, | |
446 | /*simple=*/true, NULL_TREE, | |
447 | /*before=*/true, GSI_SAME_STMT); | |
448 | tmp = fold_build2 (NE_EXPR, boolean_type_node, tmp, word_mode_zero); | |
449 | new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, test[k].target_edge, | |
450 | update_dom); | |
451 | if (update_dom) | |
9771b263 | 452 | bbs_to_fix_dom.safe_push (new_bb); |
531b10fc SB |
453 | gcc_assert (gimple_bb (swtch) == new_bb); |
454 | gsi = gsi_last_bb (new_bb); | |
455 | } | |
456 | ||
457 | /* We should have removed all edges now. */ | |
458 | gcc_assert (EDGE_COUNT (gsi_bb (gsi)->succs) == 0); | |
459 | ||
460 | /* If nothing matched, go to the default label. */ | |
461 | make_edge (gsi_bb (gsi), new_default_bb, EDGE_FALLTHRU); | |
462 | ||
463 | /* The GIMPLE_SWITCH is now redundant. */ | |
464 | gsi_remove (&gsi, true); | |
465 | ||
466 | if (update_dom) | |
467 | { | |
468 | /* Fix up the dominator tree. */ | |
469 | iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
9771b263 | 470 | bbs_to_fix_dom.release (); |
531b10fc SB |
471 | } |
472 | } | |
473 | \f | |
b6e99746 MJ |
474 | /* |
475 | Switch initialization conversion | |
476 | ||
477 | The following pass changes simple initializations of scalars in a switch | |
fade902a SB |
478 | statement into initializations from a static array. Obviously, the values |
479 | must be constant and known at compile time and a default branch must be | |
b6e99746 MJ |
480 | provided. For example, the following code: |
481 | ||
482 | int a,b; | |
483 | ||
484 | switch (argc) | |
485 | { | |
486 | case 1: | |
487 | case 2: | |
488 | a_1 = 8; | |
489 | b_1 = 6; | |
490 | break; | |
491 | case 3: | |
492 | a_2 = 9; | |
493 | b_2 = 5; | |
494 | break; | |
495 | case 12: | |
496 | a_3 = 10; | |
497 | b_3 = 4; | |
498 | break; | |
499 | default: | |
500 | a_4 = 16; | |
501 | b_4 = 1; | |
886cd84f | 502 | break; |
b6e99746 MJ |
503 | } |
504 | a_5 = PHI <a_1, a_2, a_3, a_4> | |
505 | b_5 = PHI <b_1, b_2, b_3, b_4> | |
506 | ||
507 | ||
508 | is changed into: | |
509 | ||
510 | static const int = CSWTCH01[] = {6, 6, 5, 1, 1, 1, 1, 1, 1, 1, 1, 4}; | |
511 | static const int = CSWTCH02[] = {8, 8, 9, 16, 16, 16, 16, 16, 16, 16, | |
512 | 16, 16, 10}; | |
513 | ||
514 | if (((unsigned) argc) - 1 < 11) | |
515 | { | |
516 | a_6 = CSWTCH02[argc - 1]; | |
517 | b_6 = CSWTCH01[argc - 1]; | |
518 | } | |
519 | else | |
520 | { | |
521 | a_7 = 16; | |
522 | b_7 = 1; | |
523 | } | |
886cd84f SB |
524 | a_5 = PHI <a_6, a_7> |
525 | b_b = PHI <b_6, b_7> | |
b6e99746 MJ |
526 | |
527 | There are further constraints. Specifically, the range of values across all | |
528 | case labels must not be bigger than SWITCH_CONVERSION_BRANCH_RATIO (default | |
531b10fc | 529 | eight) times the number of the actual switch branches. |
b6e99746 | 530 | |
531b10fc SB |
531 | This transformation was contributed by Martin Jambor, see this e-mail: |
532 | http://gcc.gnu.org/ml/gcc-patches/2008-07/msg00011.html */ | |
b6e99746 MJ |
533 | |
534 | /* The main structure of the pass. */ | |
535 | struct switch_conv_info | |
536 | { | |
886cd84f | 537 | /* The expression used to decide the switch branch. */ |
b6e99746 MJ |
538 | tree index_expr; |
539 | ||
886cd84f SB |
540 | /* The following integer constants store the minimum and maximum value |
541 | covered by the case labels. */ | |
b6e99746 | 542 | tree range_min; |
886cd84f | 543 | tree range_max; |
b6e99746 | 544 | |
886cd84f SB |
545 | /* The difference between the above two numbers. Stored here because it |
546 | is used in all the conversion heuristics, as well as for some of the | |
547 | transformation, and it is expensive to re-compute it all the time. */ | |
b6e99746 MJ |
548 | tree range_size; |
549 | ||
886cd84f | 550 | /* Basic block that contains the actual GIMPLE_SWITCH. */ |
b6e99746 MJ |
551 | basic_block switch_bb; |
552 | ||
886cd84f SB |
553 | /* Basic block that is the target of the default case. */ |
554 | basic_block default_bb; | |
555 | ||
556 | /* The single successor block of all branches out of the GIMPLE_SWITCH, | |
557 | if such a block exists. Otherwise NULL. */ | |
b6e99746 MJ |
558 | basic_block final_bb; |
559 | ||
886cd84f | 560 | /* The probability of the default edge in the replaced switch. */ |
357067f2 | 561 | profile_probability default_prob; |
886cd84f SB |
562 | |
563 | /* The count of the default edge in the replaced switch. */ | |
3995f3a2 | 564 | profile_count default_count; |
886cd84f SB |
565 | |
566 | /* Combined count of all other (non-default) edges in the replaced switch. */ | |
3995f3a2 | 567 | profile_count other_count; |
886cd84f | 568 | |
b6e99746 MJ |
569 | /* Number of phi nodes in the final bb (that we'll be replacing). */ |
570 | int phi_count; | |
571 | ||
b1ae1681 | 572 | /* Array of default values, in the same order as phi nodes. */ |
b6e99746 MJ |
573 | tree *default_values; |
574 | ||
575 | /* Constructors of new static arrays. */ | |
9771b263 | 576 | vec<constructor_elt, va_gc> **constructors; |
b6e99746 MJ |
577 | |
578 | /* Array of ssa names that are initialized with a value from a new static | |
579 | array. */ | |
580 | tree *target_inbound_names; | |
581 | ||
582 | /* Array of ssa names that are initialized with the default value if the | |
583 | switch expression is out of range. */ | |
584 | tree *target_outbound_names; | |
585 | ||
8dc6a926 JJ |
586 | /* VOP SSA_NAME. */ |
587 | tree target_vop; | |
588 | ||
b1ae1681 MJ |
589 | /* The first load statement that loads a temporary from a new static array. |
590 | */ | |
355fe088 | 591 | gimple *arr_ref_first; |
b6e99746 MJ |
592 | |
593 | /* The last load statement that loads a temporary from a new static array. */ | |
355fe088 | 594 | gimple *arr_ref_last; |
b6e99746 MJ |
595 | |
596 | /* String reason why the case wasn't a good candidate that is written to the | |
597 | dump file, if there is one. */ | |
598 | const char *reason; | |
8e97bc2b | 599 | |
18bfe940 JJ |
600 | /* True if default case is not used for any value between range_min and |
601 | range_max inclusive. */ | |
602 | bool contiguous_range; | |
603 | ||
604 | /* True if default case does not have the required shape for other case | |
605 | labels. */ | |
606 | bool default_case_nonstandard; | |
607 | ||
8e97bc2b JJ |
608 | /* Parameters for expand_switch_using_bit_tests. Should be computed |
609 | the same way as in expand_case. */ | |
886cd84f SB |
610 | unsigned int uniq; |
611 | unsigned int count; | |
b6e99746 MJ |
612 | }; |
613 | ||
886cd84f | 614 | /* Collect information about GIMPLE_SWITCH statement SWTCH into INFO. */ |
b6e99746 | 615 | |
886cd84f | 616 | static void |
538dd0b7 | 617 | collect_switch_conv_info (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 | 618 | { |
726a989a | 619 | unsigned int branch_num = gimple_switch_num_labels (swtch); |
886cd84f SB |
620 | tree min_case, max_case; |
621 | unsigned int count, i; | |
18bfe940 | 622 | edge e, e_default, e_first; |
886cd84f | 623 | edge_iterator ei; |
18bfe940 | 624 | basic_block first; |
886cd84f SB |
625 | |
626 | memset (info, 0, sizeof (*info)); | |
b6e99746 MJ |
627 | |
628 | /* The gimplifier has already sorted the cases by CASE_LOW and ensured there | |
fd8d363e SB |
629 | is a default label which is the first in the vector. |
630 | Collect the bits we can deduce from the CFG. */ | |
886cd84f SB |
631 | info->index_expr = gimple_switch_index (swtch); |
632 | info->switch_bb = gimple_bb (swtch); | |
18bfe940 JJ |
633 | info->default_bb |
634 | = label_to_block (CASE_LABEL (gimple_switch_default_label (swtch))); | |
886cd84f SB |
635 | e_default = find_edge (info->switch_bb, info->default_bb); |
636 | info->default_prob = e_default->probability; | |
ef30ab83 | 637 | info->default_count = e_default->count (); |
886cd84f SB |
638 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) |
639 | if (e != e_default) | |
ef30ab83 | 640 | info->other_count += e->count (); |
b6e99746 | 641 | |
18bfe940 JJ |
642 | /* Get upper and lower bounds of case values, and the covered range. */ |
643 | min_case = gimple_switch_label (swtch, 1); | |
644 | max_case = gimple_switch_label (swtch, branch_num - 1); | |
645 | ||
646 | info->range_min = CASE_LOW (min_case); | |
647 | if (CASE_HIGH (max_case) != NULL_TREE) | |
648 | info->range_max = CASE_HIGH (max_case); | |
649 | else | |
650 | info->range_max = CASE_LOW (max_case); | |
651 | ||
652 | info->contiguous_range = true; | |
653 | tree last = CASE_HIGH (min_case) ? CASE_HIGH (min_case) : info->range_min; | |
654 | for (i = 2; i < branch_num; i++) | |
655 | { | |
656 | tree elt = gimple_switch_label (swtch, i); | |
8e6cdc90 | 657 | if (wi::to_wide (last) + 1 != wi::to_wide (CASE_LOW (elt))) |
18bfe940 JJ |
658 | { |
659 | info->contiguous_range = false; | |
660 | break; | |
661 | } | |
662 | last = CASE_HIGH (elt) ? CASE_HIGH (elt) : CASE_LOW (elt); | |
663 | } | |
664 | ||
665 | if (info->contiguous_range) | |
666 | { | |
667 | first = label_to_block (CASE_LABEL (gimple_switch_label (swtch, 1))); | |
668 | e_first = find_edge (info->switch_bb, first); | |
669 | } | |
670 | else | |
671 | { | |
672 | first = info->default_bb; | |
673 | e_first = e_default; | |
674 | } | |
675 | ||
886cd84f | 676 | /* See if there is one common successor block for all branch |
866f20d6 | 677 | targets. If it exists, record it in FINAL_BB. |
18bfe940 JJ |
678 | Start with the destination of the first non-default case |
679 | if the range is contiguous and default case otherwise as | |
680 | guess or its destination in case it is a forwarder block. */ | |
681 | if (! single_pred_p (e_first->dest)) | |
682 | info->final_bb = e_first->dest; | |
683 | else if (single_succ_p (e_first->dest) | |
684 | && ! single_pred_p (single_succ (e_first->dest))) | |
685 | info->final_bb = single_succ (e_first->dest); | |
866f20d6 | 686 | /* Require that all switch destinations are either that common |
18bfe940 JJ |
687 | FINAL_BB or a forwarder to it, except for the default |
688 | case if contiguous range. */ | |
886cd84f SB |
689 | if (info->final_bb) |
690 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
691 | { | |
692 | if (e->dest == info->final_bb) | |
693 | continue; | |
694 | ||
695 | if (single_pred_p (e->dest) | |
696 | && single_succ_p (e->dest) | |
697 | && single_succ (e->dest) == info->final_bb) | |
698 | continue; | |
699 | ||
18bfe940 JJ |
700 | if (e == e_default && info->contiguous_range) |
701 | { | |
702 | info->default_case_nonstandard = true; | |
703 | continue; | |
704 | } | |
705 | ||
886cd84f SB |
706 | info->final_bb = NULL; |
707 | break; | |
708 | } | |
709 | ||
18bfe940 JJ |
710 | info->range_size |
711 | = int_const_binop (MINUS_EXPR, info->range_max, info->range_min); | |
b6e99746 | 712 | |
886cd84f SB |
713 | /* Get a count of the number of case labels. Single-valued case labels |
714 | simply count as one, but a case range counts double, since it may | |
715 | require two compares if it gets lowered as a branching tree. */ | |
716 | count = 0; | |
717 | for (i = 1; i < branch_num; i++) | |
718 | { | |
719 | tree elt = gimple_switch_label (swtch, i); | |
720 | count++; | |
721 | if (CASE_HIGH (elt) | |
722 | && ! tree_int_cst_equal (CASE_LOW (elt), CASE_HIGH (elt))) | |
723 | count++; | |
724 | } | |
725 | info->count = count; | |
726 | ||
727 | /* Get the number of unique non-default targets out of the GIMPLE_SWITCH | |
728 | block. Assume a CFG cleanup would have already removed degenerate | |
729 | switch statements, this allows us to just use EDGE_COUNT. */ | |
730 | info->uniq = EDGE_COUNT (gimple_bb (swtch)->succs) - 1; | |
731 | } | |
b6e99746 | 732 | |
886cd84f SB |
733 | /* Checks whether the range given by individual case statements of the SWTCH |
734 | switch statement isn't too big and whether the number of branches actually | |
735 | satisfies the size of the new array. */ | |
b6e99746 | 736 | |
886cd84f SB |
737 | static bool |
738 | check_range (struct switch_conv_info *info) | |
739 | { | |
fade902a | 740 | gcc_assert (info->range_size); |
cc269bb6 | 741 | if (!tree_fits_uhwi_p (info->range_size)) |
b6e99746 | 742 | { |
fade902a | 743 | info->reason = "index range way too large or otherwise unusable"; |
b6e99746 MJ |
744 | return false; |
745 | } | |
746 | ||
7d362f6c | 747 | if (tree_to_uhwi (info->range_size) |
886cd84f | 748 | > ((unsigned) info->count * SWITCH_CONVERSION_BRANCH_RATIO)) |
b6e99746 | 749 | { |
fade902a | 750 | info->reason = "the maximum range-branch ratio exceeded"; |
b6e99746 MJ |
751 | return false; |
752 | } | |
753 | ||
754 | return true; | |
755 | } | |
756 | ||
886cd84f | 757 | /* Checks whether all but the FINAL_BB basic blocks are empty. */ |
b6e99746 MJ |
758 | |
759 | static bool | |
886cd84f | 760 | check_all_empty_except_final (struct switch_conv_info *info) |
b6e99746 | 761 | { |
18bfe940 | 762 | edge e, e_default = find_edge (info->switch_bb, info->default_bb); |
886cd84f | 763 | edge_iterator ei; |
b6e99746 | 764 | |
886cd84f | 765 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) |
b6e99746 | 766 | { |
886cd84f SB |
767 | if (e->dest == info->final_bb) |
768 | continue; | |
b6e99746 | 769 | |
886cd84f | 770 | if (!empty_block_p (e->dest)) |
b6e99746 | 771 | { |
18bfe940 JJ |
772 | if (info->contiguous_range && e == e_default) |
773 | { | |
774 | info->default_case_nonstandard = true; | |
775 | continue; | |
776 | } | |
777 | ||
fade902a | 778 | info->reason = "bad case - a non-final BB not empty"; |
b6e99746 MJ |
779 | return false; |
780 | } | |
b6e99746 MJ |
781 | } |
782 | ||
783 | return true; | |
784 | } | |
785 | ||
786 | /* This function checks whether all required values in phi nodes in final_bb | |
787 | are constants. Required values are those that correspond to a basic block | |
788 | which is a part of the examined switch statement. It returns true if the | |
789 | phi nodes are OK, otherwise false. */ | |
790 | ||
791 | static bool | |
18bfe940 | 792 | check_final_bb (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 | 793 | { |
538dd0b7 | 794 | gphi_iterator gsi; |
b6e99746 | 795 | |
fade902a SB |
796 | info->phi_count = 0; |
797 | for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
b6e99746 | 798 | { |
538dd0b7 | 799 | gphi *phi = gsi.phi (); |
726a989a | 800 | unsigned int i; |
b6e99746 | 801 | |
18bfe940 JJ |
802 | if (virtual_operand_p (gimple_phi_result (phi))) |
803 | continue; | |
804 | ||
fade902a | 805 | info->phi_count++; |
b6e99746 | 806 | |
726a989a | 807 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
b6e99746 | 808 | { |
726a989a | 809 | basic_block bb = gimple_phi_arg_edge (phi, i)->src; |
b6e99746 | 810 | |
fade902a | 811 | if (bb == info->switch_bb |
18bfe940 JJ |
812 | || (single_pred_p (bb) |
813 | && single_pred (bb) == info->switch_bb | |
814 | && (!info->default_case_nonstandard | |
815 | || empty_block_p (bb)))) | |
b6e99746 | 816 | { |
f6e6e990 | 817 | tree reloc, val; |
18bfe940 | 818 | const char *reason = NULL; |
f6e6e990 JJ |
819 | |
820 | val = gimple_phi_arg_def (phi, i); | |
821 | if (!is_gimple_ip_invariant (val)) | |
18bfe940 JJ |
822 | reason = "non-invariant value from a case"; |
823 | else | |
f6e6e990 | 824 | { |
18bfe940 JJ |
825 | reloc = initializer_constant_valid_p (val, TREE_TYPE (val)); |
826 | if ((flag_pic && reloc != null_pointer_node) | |
827 | || (!flag_pic && reloc == NULL_TREE)) | |
828 | { | |
829 | if (reloc) | |
830 | reason | |
831 | = "value from a case would need runtime relocations"; | |
832 | else | |
833 | reason | |
834 | = "value from a case is not a valid initializer"; | |
835 | } | |
f6e6e990 | 836 | } |
18bfe940 | 837 | if (reason) |
f6e6e990 | 838 | { |
18bfe940 JJ |
839 | /* For contiguous range, we can allow non-constant |
840 | or one that needs relocation, as long as it is | |
841 | only reachable from the default case. */ | |
842 | if (bb == info->switch_bb) | |
843 | bb = info->final_bb; | |
844 | if (!info->contiguous_range || bb != info->default_bb) | |
845 | { | |
846 | info->reason = reason; | |
847 | return false; | |
848 | } | |
849 | ||
850 | unsigned int branch_num = gimple_switch_num_labels (swtch); | |
851 | for (unsigned int i = 1; i < branch_num; i++) | |
852 | { | |
853 | tree lab = CASE_LABEL (gimple_switch_label (swtch, i)); | |
854 | if (label_to_block (lab) == bb) | |
855 | { | |
856 | info->reason = reason; | |
857 | return false; | |
858 | } | |
859 | } | |
860 | info->default_case_nonstandard = true; | |
f6e6e990 | 861 | } |
b6e99746 MJ |
862 | } |
863 | } | |
864 | } | |
865 | ||
866 | return true; | |
867 | } | |
868 | ||
869 | /* The following function allocates default_values, target_{in,out}_names and | |
870 | constructors arrays. The last one is also populated with pointers to | |
871 | vectors that will become constructors of new arrays. */ | |
872 | ||
873 | static void | |
fade902a | 874 | create_temp_arrays (struct switch_conv_info *info) |
b6e99746 MJ |
875 | { |
876 | int i; | |
877 | ||
fade902a | 878 | info->default_values = XCNEWVEC (tree, info->phi_count * 3); |
9771b263 DN |
879 | /* ??? Macros do not support multi argument templates in their |
880 | argument list. We create a typedef to work around that problem. */ | |
881 | typedef vec<constructor_elt, va_gc> *vec_constructor_elt_gc; | |
882 | info->constructors = XCNEWVEC (vec_constructor_elt_gc, info->phi_count); | |
fade902a SB |
883 | info->target_inbound_names = info->default_values + info->phi_count; |
884 | info->target_outbound_names = info->target_inbound_names + info->phi_count; | |
885 | for (i = 0; i < info->phi_count; i++) | |
ae7e9ddd | 886 | vec_alloc (info->constructors[i], tree_to_uhwi (info->range_size) + 1); |
b6e99746 MJ |
887 | } |
888 | ||
889 | /* Free the arrays created by create_temp_arrays(). The vectors that are | |
890 | created by that function are not freed here, however, because they have | |
891 | already become constructors and must be preserved. */ | |
892 | ||
893 | static void | |
fade902a | 894 | free_temp_arrays (struct switch_conv_info *info) |
b6e99746 | 895 | { |
fade902a SB |
896 | XDELETEVEC (info->constructors); |
897 | XDELETEVEC (info->default_values); | |
b6e99746 MJ |
898 | } |
899 | ||
900 | /* Populate the array of default values in the order of phi nodes. | |
18bfe940 JJ |
901 | DEFAULT_CASE is the CASE_LABEL_EXPR for the default switch branch |
902 | if the range is non-contiguous or the default case has standard | |
903 | structure, otherwise it is the first non-default case instead. */ | |
b6e99746 MJ |
904 | |
905 | static void | |
fade902a | 906 | gather_default_values (tree default_case, struct switch_conv_info *info) |
b6e99746 | 907 | { |
538dd0b7 | 908 | gphi_iterator gsi; |
b6e99746 MJ |
909 | basic_block bb = label_to_block (CASE_LABEL (default_case)); |
910 | edge e; | |
726a989a | 911 | int i = 0; |
b6e99746 | 912 | |
18bfe940 JJ |
913 | gcc_assert (CASE_LOW (default_case) == NULL_TREE |
914 | || info->default_case_nonstandard); | |
b6e99746 | 915 | |
fade902a SB |
916 | if (bb == info->final_bb) |
917 | e = find_edge (info->switch_bb, bb); | |
b6e99746 MJ |
918 | else |
919 | e = single_succ_edge (bb); | |
920 | ||
fade902a | 921 | for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
b6e99746 | 922 | { |
538dd0b7 | 923 | gphi *phi = gsi.phi (); |
18bfe940 JJ |
924 | if (virtual_operand_p (gimple_phi_result (phi))) |
925 | continue; | |
b6e99746 MJ |
926 | tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
927 | gcc_assert (val); | |
fade902a | 928 | info->default_values[i++] = val; |
b6e99746 MJ |
929 | } |
930 | } | |
931 | ||
932 | /* The following function populates the vectors in the constructors array with | |
933 | future contents of the static arrays. The vectors are populated in the | |
934 | order of phi nodes. SWTCH is the switch statement being converted. */ | |
935 | ||
936 | static void | |
538dd0b7 | 937 | build_constructors (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 | 938 | { |
726a989a | 939 | unsigned i, branch_num = gimple_switch_num_labels (swtch); |
fade902a | 940 | tree pos = info->range_min; |
18bfe940 | 941 | tree pos_one = build_int_cst (TREE_TYPE (pos), 1); |
b6e99746 | 942 | |
726a989a | 943 | for (i = 1; i < branch_num; i++) |
b6e99746 | 944 | { |
726a989a | 945 | tree cs = gimple_switch_label (swtch, i); |
b6e99746 MJ |
946 | basic_block bb = label_to_block (CASE_LABEL (cs)); |
947 | edge e; | |
726a989a | 948 | tree high; |
538dd0b7 | 949 | gphi_iterator gsi; |
b6e99746 MJ |
950 | int j; |
951 | ||
fade902a SB |
952 | if (bb == info->final_bb) |
953 | e = find_edge (info->switch_bb, bb); | |
b6e99746 MJ |
954 | else |
955 | e = single_succ_edge (bb); | |
956 | gcc_assert (e); | |
957 | ||
958 | while (tree_int_cst_lt (pos, CASE_LOW (cs))) | |
959 | { | |
960 | int k; | |
18bfe940 | 961 | gcc_assert (!info->contiguous_range); |
fade902a | 962 | for (k = 0; k < info->phi_count; k++) |
b6e99746 | 963 | { |
f32682ca | 964 | constructor_elt elt; |
b6e99746 | 965 | |
f32682ca | 966 | elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); |
d1f98542 RB |
967 | elt.value |
968 | = unshare_expr_without_location (info->default_values[k]); | |
9771b263 | 969 | info->constructors[k]->quick_push (elt); |
b6e99746 MJ |
970 | } |
971 | ||
18bfe940 | 972 | pos = int_const_binop (PLUS_EXPR, pos, pos_one); |
b6e99746 | 973 | } |
b1ae1681 | 974 | gcc_assert (tree_int_cst_equal (pos, CASE_LOW (cs))); |
b6e99746 MJ |
975 | |
976 | j = 0; | |
977 | if (CASE_HIGH (cs)) | |
978 | high = CASE_HIGH (cs); | |
979 | else | |
b1ae1681 | 980 | high = CASE_LOW (cs); |
fade902a | 981 | for (gsi = gsi_start_phis (info->final_bb); |
726a989a | 982 | !gsi_end_p (gsi); gsi_next (&gsi)) |
b6e99746 | 983 | { |
538dd0b7 | 984 | gphi *phi = gsi.phi (); |
18bfe940 JJ |
985 | if (virtual_operand_p (gimple_phi_result (phi))) |
986 | continue; | |
b6e99746 | 987 | tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
7f2a9982 | 988 | tree low = CASE_LOW (cs); |
b6e99746 MJ |
989 | pos = CASE_LOW (cs); |
990 | ||
b8698a0f | 991 | do |
b6e99746 | 992 | { |
f32682ca | 993 | constructor_elt elt; |
b6e99746 | 994 | |
f32682ca | 995 | elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); |
d1f98542 | 996 | elt.value = unshare_expr_without_location (val); |
9771b263 | 997 | info->constructors[j]->quick_push (elt); |
b6e99746 | 998 | |
18bfe940 | 999 | pos = int_const_binop (PLUS_EXPR, pos, pos_one); |
7156c8ab MJ |
1000 | } while (!tree_int_cst_lt (high, pos) |
1001 | && tree_int_cst_lt (low, pos)); | |
b6e99746 MJ |
1002 | j++; |
1003 | } | |
1004 | } | |
1005 | } | |
1006 | ||
7156c8ab MJ |
1007 | /* If all values in the constructor vector are the same, return the value. |
1008 | Otherwise return NULL_TREE. Not supposed to be called for empty | |
1009 | vectors. */ | |
1010 | ||
1011 | static tree | |
9771b263 | 1012 | constructor_contains_same_values_p (vec<constructor_elt, va_gc> *vec) |
7156c8ab | 1013 | { |
8e97bc2b | 1014 | unsigned int i; |
7156c8ab | 1015 | tree prev = NULL_TREE; |
8e97bc2b | 1016 | constructor_elt *elt; |
7156c8ab | 1017 | |
9771b263 | 1018 | FOR_EACH_VEC_SAFE_ELT (vec, i, elt) |
7156c8ab | 1019 | { |
7156c8ab MJ |
1020 | if (!prev) |
1021 | prev = elt->value; | |
1022 | else if (!operand_equal_p (elt->value, prev, OEP_ONLY_CONST)) | |
1023 | return NULL_TREE; | |
1024 | } | |
1025 | return prev; | |
1026 | } | |
1027 | ||
f1b0632a OH |
1028 | /* Return type which should be used for array elements, either TYPE's |
1029 | main variant or, for integral types, some smaller integral type | |
1030 | that can still hold all the constants. */ | |
8e97bc2b JJ |
1031 | |
1032 | static tree | |
538dd0b7 | 1033 | array_value_type (gswitch *swtch, tree type, int num, |
fade902a | 1034 | struct switch_conv_info *info) |
8e97bc2b | 1035 | { |
9771b263 | 1036 | unsigned int i, len = vec_safe_length (info->constructors[num]); |
8e97bc2b | 1037 | constructor_elt *elt; |
8e97bc2b JJ |
1038 | int sign = 0; |
1039 | tree smaller_type; | |
1040 | ||
f1b0632a OH |
1041 | /* Types with alignments greater than their size can reach here, e.g. out of |
1042 | SRA. We couldn't use these as an array component type so get back to the | |
1043 | main variant first, which, for our purposes, is fine for other types as | |
1044 | well. */ | |
1045 | ||
1046 | type = TYPE_MAIN_VARIANT (type); | |
1047 | ||
8e97bc2b JJ |
1048 | if (!INTEGRAL_TYPE_P (type)) |
1049 | return type; | |
1050 | ||
7a504f33 | 1051 | scalar_int_mode type_mode = SCALAR_INT_TYPE_MODE (type); |
095a2d76 | 1052 | scalar_int_mode mode = get_narrowest_mode (type_mode); |
ec35d572 | 1053 | if (GET_MODE_SIZE (type_mode) <= GET_MODE_SIZE (mode)) |
8e97bc2b JJ |
1054 | return type; |
1055 | ||
1056 | if (len < (optimize_bb_for_size_p (gimple_bb (swtch)) ? 2 : 32)) | |
1057 | return type; | |
1058 | ||
9771b263 | 1059 | FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
8e97bc2b | 1060 | { |
807e902e | 1061 | wide_int cst; |
8e97bc2b JJ |
1062 | |
1063 | if (TREE_CODE (elt->value) != INTEGER_CST) | |
1064 | return type; | |
1065 | ||
8e6cdc90 | 1066 | cst = wi::to_wide (elt->value); |
8e97bc2b JJ |
1067 | while (1) |
1068 | { | |
1069 | unsigned int prec = GET_MODE_BITSIZE (mode); | |
1070 | if (prec > HOST_BITS_PER_WIDE_INT) | |
1071 | return type; | |
1072 | ||
807e902e | 1073 | if (sign >= 0 && cst == wi::zext (cst, prec)) |
8e97bc2b | 1074 | { |
807e902e | 1075 | if (sign == 0 && cst == wi::sext (cst, prec)) |
8e97bc2b JJ |
1076 | break; |
1077 | sign = 1; | |
1078 | break; | |
1079 | } | |
807e902e | 1080 | if (sign <= 0 && cst == wi::sext (cst, prec)) |
8e97bc2b JJ |
1081 | { |
1082 | sign = -1; | |
1083 | break; | |
1084 | } | |
1085 | ||
1086 | if (sign == 1) | |
1087 | sign = 0; | |
1088 | ||
490d0f6c | 1089 | if (!GET_MODE_WIDER_MODE (mode).exists (&mode) |
ec35d572 | 1090 | || GET_MODE_SIZE (mode) >= GET_MODE_SIZE (type_mode)) |
8e97bc2b JJ |
1091 | return type; |
1092 | } | |
1093 | } | |
1094 | ||
1095 | if (sign == 0) | |
1096 | sign = TYPE_UNSIGNED (type) ? 1 : -1; | |
1097 | smaller_type = lang_hooks.types.type_for_mode (mode, sign >= 0); | |
7a504f33 RS |
1098 | if (GET_MODE_SIZE (type_mode) |
1099 | <= GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (smaller_type))) | |
8e97bc2b JJ |
1100 | return type; |
1101 | ||
1102 | return smaller_type; | |
1103 | } | |
1104 | ||
b6e99746 MJ |
1105 | /* Create an appropriate array type and declaration and assemble a static array |
1106 | variable. Also create a load statement that initializes the variable in | |
1107 | question with a value from the static array. SWTCH is the switch statement | |
1108 | being converted, NUM is the index to arrays of constructors, default values | |
1109 | and target SSA names for this particular array. ARR_INDEX_TYPE is the type | |
1110 | of the index of the new array, PHI is the phi node of the final BB that | |
1111 | corresponds to the value that will be loaded from the created array. TIDX | |
7156c8ab MJ |
1112 | is an ssa name of a temporary variable holding the index for loads from the |
1113 | new array. */ | |
b6e99746 MJ |
1114 | |
1115 | static void | |
538dd0b7 DM |
1116 | build_one_array (gswitch *swtch, int num, tree arr_index_type, |
1117 | gphi *phi, tree tidx, struct switch_conv_info *info) | |
b6e99746 | 1118 | { |
7156c8ab | 1119 | tree name, cst; |
355fe088 | 1120 | gimple *load; |
7156c8ab | 1121 | gimple_stmt_iterator gsi = gsi_for_stmt (swtch); |
c2255bc4 | 1122 | location_t loc = gimple_location (swtch); |
b6e99746 | 1123 | |
fade902a | 1124 | gcc_assert (info->default_values[num]); |
b6e99746 | 1125 | |
b731b390 | 1126 | name = copy_ssa_name (PHI_RESULT (phi)); |
fade902a | 1127 | info->target_inbound_names[num] = name; |
b6e99746 | 1128 | |
fade902a | 1129 | cst = constructor_contains_same_values_p (info->constructors[num]); |
7156c8ab MJ |
1130 | if (cst) |
1131 | load = gimple_build_assign (name, cst); | |
1132 | else | |
1133 | { | |
8e97bc2b | 1134 | tree array_type, ctor, decl, value_type, fetch, default_type; |
7156c8ab | 1135 | |
fade902a SB |
1136 | default_type = TREE_TYPE (info->default_values[num]); |
1137 | value_type = array_value_type (swtch, default_type, num, info); | |
7156c8ab | 1138 | array_type = build_array_type (value_type, arr_index_type); |
8e97bc2b JJ |
1139 | if (default_type != value_type) |
1140 | { | |
1141 | unsigned int i; | |
1142 | constructor_elt *elt; | |
1143 | ||
9771b263 | 1144 | FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
8e97bc2b JJ |
1145 | elt->value = fold_convert (value_type, elt->value); |
1146 | } | |
fade902a | 1147 | ctor = build_constructor (array_type, info->constructors[num]); |
7156c8ab | 1148 | TREE_CONSTANT (ctor) = true; |
5f7ae6b6 | 1149 | TREE_STATIC (ctor) = true; |
7156c8ab | 1150 | |
c2255bc4 | 1151 | decl = build_decl (loc, VAR_DECL, NULL_TREE, array_type); |
7156c8ab MJ |
1152 | TREE_STATIC (decl) = 1; |
1153 | DECL_INITIAL (decl) = ctor; | |
1154 | ||
1155 | DECL_NAME (decl) = create_tmp_var_name ("CSWTCH"); | |
1156 | DECL_ARTIFICIAL (decl) = 1; | |
f8d851c6 | 1157 | DECL_IGNORED_P (decl) = 1; |
7156c8ab | 1158 | TREE_CONSTANT (decl) = 1; |
2e3b4885 | 1159 | TREE_READONLY (decl) = 1; |
d7438551 | 1160 | DECL_IGNORED_P (decl) = 1; |
9041d2e6 | 1161 | varpool_node::finalize_decl (decl); |
7156c8ab MJ |
1162 | |
1163 | fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE, | |
1164 | NULL_TREE); | |
8e97bc2b JJ |
1165 | if (default_type != value_type) |
1166 | { | |
1167 | fetch = fold_convert (default_type, fetch); | |
1168 | fetch = force_gimple_operand_gsi (&gsi, fetch, true, NULL_TREE, | |
1169 | true, GSI_SAME_STMT); | |
1170 | } | |
7156c8ab MJ |
1171 | load = gimple_build_assign (name, fetch); |
1172 | } | |
b6e99746 | 1173 | |
726a989a | 1174 | gsi_insert_before (&gsi, load, GSI_SAME_STMT); |
7156c8ab | 1175 | update_stmt (load); |
fade902a | 1176 | info->arr_ref_last = load; |
b6e99746 MJ |
1177 | } |
1178 | ||
1179 | /* Builds and initializes static arrays initialized with values gathered from | |
1180 | the SWTCH switch statement. Also creates statements that load values from | |
1181 | them. */ | |
1182 | ||
1183 | static void | |
538dd0b7 | 1184 | build_arrays (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 MJ |
1185 | { |
1186 | tree arr_index_type; | |
83d5977e | 1187 | tree tidx, sub, utype; |
355fe088 | 1188 | gimple *stmt; |
726a989a | 1189 | gimple_stmt_iterator gsi; |
538dd0b7 | 1190 | gphi_iterator gpi; |
b6e99746 | 1191 | int i; |
db3927fb | 1192 | location_t loc = gimple_location (swtch); |
b6e99746 | 1193 | |
726a989a | 1194 | gsi = gsi_for_stmt (swtch); |
04e78aa9 | 1195 | |
edb9b69e | 1196 | /* Make sure we do not generate arithmetics in a subrange. */ |
fade902a | 1197 | utype = TREE_TYPE (info->index_expr); |
edb9b69e JJ |
1198 | if (TREE_TYPE (utype)) |
1199 | utype = lang_hooks.types.type_for_mode (TYPE_MODE (TREE_TYPE (utype)), 1); | |
1200 | else | |
1201 | utype = lang_hooks.types.type_for_mode (TYPE_MODE (utype), 1); | |
1202 | ||
fade902a | 1203 | arr_index_type = build_index_type (info->range_size); |
b731b390 | 1204 | tidx = make_ssa_name (utype); |
edb9b69e | 1205 | sub = fold_build2_loc (loc, MINUS_EXPR, utype, |
fade902a SB |
1206 | fold_convert_loc (loc, utype, info->index_expr), |
1207 | fold_convert_loc (loc, utype, info->range_min)); | |
fae1034e | 1208 | sub = force_gimple_operand_gsi (&gsi, sub, |
726a989a RB |
1209 | false, NULL, true, GSI_SAME_STMT); |
1210 | stmt = gimple_build_assign (tidx, sub); | |
b6e99746 | 1211 | |
726a989a | 1212 | gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); |
7156c8ab | 1213 | update_stmt (stmt); |
fade902a | 1214 | info->arr_ref_first = stmt; |
b6e99746 | 1215 | |
538dd0b7 | 1216 | for (gpi = gsi_start_phis (info->final_bb), i = 0; |
18bfe940 JJ |
1217 | !gsi_end_p (gpi); gsi_next (&gpi)) |
1218 | { | |
1219 | gphi *phi = gpi.phi (); | |
1220 | if (!virtual_operand_p (gimple_phi_result (phi))) | |
1221 | build_one_array (swtch, i++, arr_index_type, phi, tidx, info); | |
8dc6a926 JJ |
1222 | else |
1223 | { | |
1224 | edge e; | |
1225 | edge_iterator ei; | |
1226 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
1227 | { | |
1228 | if (e->dest == info->final_bb) | |
1229 | break; | |
1230 | if (!info->default_case_nonstandard | |
1231 | || e->dest != info->default_bb) | |
1232 | { | |
1233 | e = single_succ_edge (e->dest); | |
1234 | break; | |
1235 | } | |
1236 | } | |
1237 | gcc_assert (e && e->dest == info->final_bb); | |
1238 | info->target_vop = PHI_ARG_DEF_FROM_EDGE (phi, e); | |
1239 | } | |
18bfe940 | 1240 | } |
b6e99746 MJ |
1241 | } |
1242 | ||
1243 | /* Generates and appropriately inserts loads of default values at the position | |
1244 | given by BSI. Returns the last inserted statement. */ | |
1245 | ||
538dd0b7 | 1246 | static gassign * |
fade902a | 1247 | gen_def_assigns (gimple_stmt_iterator *gsi, struct switch_conv_info *info) |
b6e99746 MJ |
1248 | { |
1249 | int i; | |
538dd0b7 | 1250 | gassign *assign = NULL; |
b6e99746 | 1251 | |
fade902a | 1252 | for (i = 0; i < info->phi_count; i++) |
b6e99746 | 1253 | { |
b731b390 | 1254 | tree name = copy_ssa_name (info->target_inbound_names[i]); |
fade902a SB |
1255 | info->target_outbound_names[i] = name; |
1256 | assign = gimple_build_assign (name, info->default_values[i]); | |
726a989a | 1257 | gsi_insert_before (gsi, assign, GSI_SAME_STMT); |
7156c8ab | 1258 | update_stmt (assign); |
b6e99746 MJ |
1259 | } |
1260 | return assign; | |
1261 | } | |
1262 | ||
1263 | /* Deletes the unused bbs and edges that now contain the switch statement and | |
1264 | its empty branch bbs. BBD is the now dead BB containing the original switch | |
1265 | statement, FINAL is the last BB of the converted switch statement (in terms | |
1266 | of succession). */ | |
1267 | ||
1268 | static void | |
18bfe940 | 1269 | prune_bbs (basic_block bbd, basic_block final, basic_block default_bb) |
b6e99746 MJ |
1270 | { |
1271 | edge_iterator ei; | |
1272 | edge e; | |
1273 | ||
1274 | for (ei = ei_start (bbd->succs); (e = ei_safe_edge (ei)); ) | |
1275 | { | |
1276 | basic_block bb; | |
1277 | bb = e->dest; | |
1278 | remove_edge (e); | |
18bfe940 | 1279 | if (bb != final && bb != default_bb) |
b6e99746 MJ |
1280 | delete_basic_block (bb); |
1281 | } | |
1282 | delete_basic_block (bbd); | |
1283 | } | |
1284 | ||
1285 | /* Add values to phi nodes in final_bb for the two new edges. E1F is the edge | |
1286 | from the basic block loading values from an array and E2F from the basic | |
1287 | block loading default values. BBF is the last switch basic block (see the | |
1288 | bbf description in the comment below). */ | |
1289 | ||
1290 | static void | |
fade902a SB |
1291 | fix_phi_nodes (edge e1f, edge e2f, basic_block bbf, |
1292 | struct switch_conv_info *info) | |
b6e99746 | 1293 | { |
538dd0b7 | 1294 | gphi_iterator gsi; |
b6e99746 MJ |
1295 | int i; |
1296 | ||
726a989a | 1297 | for (gsi = gsi_start_phis (bbf), i = 0; |
18bfe940 | 1298 | !gsi_end_p (gsi); gsi_next (&gsi)) |
b6e99746 | 1299 | { |
538dd0b7 | 1300 | gphi *phi = gsi.phi (); |
18bfe940 JJ |
1301 | tree inbound, outbound; |
1302 | if (virtual_operand_p (gimple_phi_result (phi))) | |
8dc6a926 | 1303 | inbound = outbound = info->target_vop; |
18bfe940 JJ |
1304 | else |
1305 | { | |
1306 | inbound = info->target_inbound_names[i]; | |
1307 | outbound = info->target_outbound_names[i++]; | |
1308 | } | |
1309 | add_phi_arg (phi, inbound, e1f, UNKNOWN_LOCATION); | |
1310 | if (!info->default_case_nonstandard) | |
1311 | add_phi_arg (phi, outbound, e2f, UNKNOWN_LOCATION); | |
b6e99746 | 1312 | } |
b6e99746 MJ |
1313 | } |
1314 | ||
1315 | /* Creates a check whether the switch expression value actually falls into the | |
1316 | range given by all the cases. If it does not, the temporaries are loaded | |
1317 | with default values instead. SWTCH is the switch statement being converted. | |
1318 | ||
1319 | bb0 is the bb with the switch statement, however, we'll end it with a | |
1320 | condition instead. | |
1321 | ||
1322 | bb1 is the bb to be used when the range check went ok. It is derived from | |
1323 | the switch BB | |
1324 | ||
1325 | bb2 is the bb taken when the expression evaluated outside of the range | |
1326 | covered by the created arrays. It is populated by loads of default | |
1327 | values. | |
1328 | ||
1329 | bbF is a fall through for both bb1 and bb2 and contains exactly what | |
1330 | originally followed the switch statement. | |
1331 | ||
1332 | bbD contains the switch statement (in the end). It is unreachable but we | |
1333 | still need to strip off its edges. | |
1334 | */ | |
1335 | ||
1336 | static void | |
538dd0b7 | 1337 | gen_inbound_check (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 | 1338 | { |
c2255bc4 AH |
1339 | tree label_decl1 = create_artificial_label (UNKNOWN_LOCATION); |
1340 | tree label_decl2 = create_artificial_label (UNKNOWN_LOCATION); | |
1341 | tree label_decl3 = create_artificial_label (UNKNOWN_LOCATION); | |
538dd0b7 | 1342 | glabel *label1, *label2, *label3; |
edb9b69e | 1343 | tree utype, tidx; |
b6e99746 MJ |
1344 | tree bound; |
1345 | ||
538dd0b7 | 1346 | gcond *cond_stmt; |
b6e99746 | 1347 | |
18bfe940 | 1348 | gassign *last_assign = NULL; |
726a989a | 1349 | gimple_stmt_iterator gsi; |
b6e99746 | 1350 | basic_block bb0, bb1, bb2, bbf, bbd; |
18bfe940 | 1351 | edge e01 = NULL, e02, e21, e1d, e1f, e2f; |
db3927fb | 1352 | location_t loc = gimple_location (swtch); |
b6e99746 | 1353 | |
fade902a | 1354 | gcc_assert (info->default_values); |
6ab1ab14 | 1355 | |
726a989a | 1356 | bb0 = gimple_bb (swtch); |
b6e99746 | 1357 | |
fade902a | 1358 | tidx = gimple_assign_lhs (info->arr_ref_first); |
edb9b69e | 1359 | utype = TREE_TYPE (tidx); |
145544ab | 1360 | |
b6e99746 | 1361 | /* (end of) block 0 */ |
fade902a | 1362 | gsi = gsi_for_stmt (info->arr_ref_first); |
edb9b69e | 1363 | gsi_next (&gsi); |
b6e99746 | 1364 | |
fade902a | 1365 | bound = fold_convert_loc (loc, utype, info->range_size); |
edb9b69e | 1366 | cond_stmt = gimple_build_cond (LE_EXPR, tidx, bound, NULL_TREE, NULL_TREE); |
726a989a | 1367 | gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT); |
7156c8ab | 1368 | update_stmt (cond_stmt); |
b6e99746 MJ |
1369 | |
1370 | /* block 2 */ | |
18bfe940 JJ |
1371 | if (!info->default_case_nonstandard) |
1372 | { | |
1373 | label2 = gimple_build_label (label_decl2); | |
1374 | gsi_insert_before (&gsi, label2, GSI_SAME_STMT); | |
1375 | last_assign = gen_def_assigns (&gsi, info); | |
1376 | } | |
b6e99746 MJ |
1377 | |
1378 | /* block 1 */ | |
726a989a RB |
1379 | label1 = gimple_build_label (label_decl1); |
1380 | gsi_insert_before (&gsi, label1, GSI_SAME_STMT); | |
b6e99746 MJ |
1381 | |
1382 | /* block F */ | |
fade902a | 1383 | gsi = gsi_start_bb (info->final_bb); |
726a989a RB |
1384 | label3 = gimple_build_label (label_decl3); |
1385 | gsi_insert_before (&gsi, label3, GSI_SAME_STMT); | |
b6e99746 MJ |
1386 | |
1387 | /* cfg fix */ | |
726a989a | 1388 | e02 = split_block (bb0, cond_stmt); |
b6e99746 MJ |
1389 | bb2 = e02->dest; |
1390 | ||
18bfe940 JJ |
1391 | if (info->default_case_nonstandard) |
1392 | { | |
1393 | bb1 = bb2; | |
1394 | bb2 = info->default_bb; | |
1395 | e01 = e02; | |
1396 | e01->flags = EDGE_TRUE_VALUE; | |
1397 | e02 = make_edge (bb0, bb2, EDGE_FALSE_VALUE); | |
1398 | edge e_default = find_edge (bb1, bb2); | |
1399 | for (gphi_iterator gsi = gsi_start_phis (bb2); | |
1400 | !gsi_end_p (gsi); gsi_next (&gsi)) | |
1401 | { | |
1402 | gphi *phi = gsi.phi (); | |
1403 | tree arg = PHI_ARG_DEF_FROM_EDGE (phi, e_default); | |
1404 | add_phi_arg (phi, arg, e02, | |
1405 | gimple_phi_arg_location_from_edge (phi, e_default)); | |
1406 | } | |
1407 | /* Partially fix the dominator tree, if it is available. */ | |
1408 | if (dom_info_available_p (CDI_DOMINATORS)) | |
1409 | redirect_immediate_dominators (CDI_DOMINATORS, bb1, bb0); | |
1410 | } | |
1411 | else | |
1412 | { | |
1413 | e21 = split_block (bb2, last_assign); | |
1414 | bb1 = e21->dest; | |
1415 | remove_edge (e21); | |
1416 | } | |
b6e99746 | 1417 | |
fade902a | 1418 | e1d = split_block (bb1, info->arr_ref_last); |
b6e99746 MJ |
1419 | bbd = e1d->dest; |
1420 | remove_edge (e1d); | |
1421 | ||
1422 | /* flags and profiles of the edge for in-range values */ | |
18bfe940 JJ |
1423 | if (!info->default_case_nonstandard) |
1424 | e01 = make_edge (bb0, bb1, EDGE_TRUE_VALUE); | |
357067f2 | 1425 | e01->probability = info->default_prob.invert (); |
b6e99746 MJ |
1426 | |
1427 | /* flags and profiles of the edge taking care of out-of-range values */ | |
1428 | e02->flags &= ~EDGE_FALLTHRU; | |
1429 | e02->flags |= EDGE_FALSE_VALUE; | |
fade902a | 1430 | e02->probability = info->default_prob; |
b6e99746 | 1431 | |
fade902a | 1432 | bbf = info->final_bb; |
b6e99746 MJ |
1433 | |
1434 | e1f = make_edge (bb1, bbf, EDGE_FALLTHRU); | |
357067f2 | 1435 | e1f->probability = profile_probability::always (); |
b6e99746 | 1436 | |
18bfe940 JJ |
1437 | if (info->default_case_nonstandard) |
1438 | e2f = NULL; | |
1439 | else | |
1440 | { | |
1441 | e2f = make_edge (bb2, bbf, EDGE_FALLTHRU); | |
357067f2 | 1442 | e2f->probability = profile_probability::always (); |
18bfe940 | 1443 | } |
b6e99746 MJ |
1444 | |
1445 | /* frequencies of the new BBs */ | |
1446 | bb1->frequency = EDGE_FREQUENCY (e01); | |
1447 | bb2->frequency = EDGE_FREQUENCY (e02); | |
18bfe940 JJ |
1448 | if (!info->default_case_nonstandard) |
1449 | bbf->frequency = EDGE_FREQUENCY (e1f) + EDGE_FREQUENCY (e2f); | |
b6e99746 | 1450 | |
6ab1ab14 | 1451 | /* Tidy blocks that have become unreachable. */ |
18bfe940 JJ |
1452 | prune_bbs (bbd, info->final_bb, |
1453 | info->default_case_nonstandard ? info->default_bb : NULL); | |
b6e99746 | 1454 | |
6ab1ab14 | 1455 | /* Fixup the PHI nodes in bbF. */ |
fade902a | 1456 | fix_phi_nodes (e1f, e2f, bbf, info); |
b6e99746 | 1457 | |
6ab1ab14 SB |
1458 | /* Fix the dominator tree, if it is available. */ |
1459 | if (dom_info_available_p (CDI_DOMINATORS)) | |
1460 | { | |
9771b263 | 1461 | vec<basic_block> bbs_to_fix_dom; |
6ab1ab14 SB |
1462 | |
1463 | set_immediate_dominator (CDI_DOMINATORS, bb1, bb0); | |
18bfe940 JJ |
1464 | if (!info->default_case_nonstandard) |
1465 | set_immediate_dominator (CDI_DOMINATORS, bb2, bb0); | |
531b10fc | 1466 | if (! get_immediate_dominator (CDI_DOMINATORS, bbf)) |
6ab1ab14 SB |
1467 | /* If bbD was the immediate dominator ... */ |
1468 | set_immediate_dominator (CDI_DOMINATORS, bbf, bb0); | |
1469 | ||
18bfe940 | 1470 | bbs_to_fix_dom.create (3 + (bb2 != bbf)); |
9771b263 DN |
1471 | bbs_to_fix_dom.quick_push (bb0); |
1472 | bbs_to_fix_dom.quick_push (bb1); | |
18bfe940 JJ |
1473 | if (bb2 != bbf) |
1474 | bbs_to_fix_dom.quick_push (bb2); | |
9771b263 | 1475 | bbs_to_fix_dom.quick_push (bbf); |
6ab1ab14 SB |
1476 | |
1477 | iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
9771b263 | 1478 | bbs_to_fix_dom.release (); |
6ab1ab14 | 1479 | } |
b6e99746 MJ |
1480 | } |
1481 | ||
1482 | /* The following function is invoked on every switch statement (the current one | |
1483 | is given in SWTCH) and runs the individual phases of switch conversion on it | |
fade902a SB |
1484 | one after another until one fails or the conversion is completed. |
1485 | Returns NULL on success, or a pointer to a string with the reason why the | |
1486 | conversion failed. */ | |
b6e99746 | 1487 | |
fade902a | 1488 | static const char * |
538dd0b7 | 1489 | process_switch (gswitch *swtch) |
b6e99746 | 1490 | { |
fade902a | 1491 | struct switch_conv_info info; |
b6e99746 | 1492 | |
238065a7 SB |
1493 | /* Group case labels so that we get the right results from the heuristics |
1494 | that decide on the code generation approach for this switch. */ | |
1495 | group_case_labels_stmt (swtch); | |
1496 | ||
1497 | /* If this switch is now a degenerate case with only a default label, | |
1498 | there is nothing left for us to do. */ | |
1499 | if (gimple_switch_num_labels (swtch) < 2) | |
1500 | return "switch is a degenerate case"; | |
886cd84f SB |
1501 | |
1502 | collect_switch_conv_info (swtch, &info); | |
1503 | ||
1504 | /* No error markers should reach here (they should be filtered out | |
1505 | during gimplification). */ | |
1506 | gcc_checking_assert (TREE_TYPE (info.index_expr) != error_mark_node); | |
1507 | ||
531b10fc SB |
1508 | /* A switch on a constant should have been optimized in tree-cfg-cleanup. */ |
1509 | gcc_checking_assert (! TREE_CONSTANT (info.index_expr)); | |
886cd84f | 1510 | |
531b10fc | 1511 | if (info.uniq <= MAX_CASE_BIT_TESTS) |
886cd84f | 1512 | { |
531b10fc | 1513 | if (expand_switch_using_bit_tests_p (info.range_size, |
72798784 RB |
1514 | info.uniq, info.count, |
1515 | optimize_bb_for_speed_p | |
1516 | (gimple_bb (swtch)))) | |
531b10fc SB |
1517 | { |
1518 | if (dump_file) | |
1519 | fputs (" expanding as bit test is preferable\n", dump_file); | |
aa79a1e1 JJ |
1520 | emit_case_bit_tests (swtch, info.index_expr, info.range_min, |
1521 | info.range_size, info.range_max); | |
726338f4 | 1522 | loops_state_set (LOOPS_NEED_FIXUP); |
531b10fc SB |
1523 | return NULL; |
1524 | } | |
1525 | ||
1526 | if (info.uniq <= 2) | |
1527 | /* This will be expanded as a decision tree in stmt.c:expand_case. */ | |
1528 | return " expanding as jumps is preferable"; | |
886cd84f | 1529 | } |
b6e99746 | 1530 | |
531b10fc SB |
1531 | /* If there is no common successor, we cannot do the transformation. */ |
1532 | if (! info.final_bb) | |
1533 | return "no common successor to all case label target blocks found"; | |
1534 | ||
b6e99746 | 1535 | /* Check the case label values are within reasonable range: */ |
886cd84f | 1536 | if (!check_range (&info)) |
fade902a SB |
1537 | { |
1538 | gcc_assert (info.reason); | |
1539 | return info.reason; | |
1540 | } | |
b6e99746 MJ |
1541 | |
1542 | /* For all the cases, see whether they are empty, the assignments they | |
1543 | represent constant and so on... */ | |
886cd84f | 1544 | if (! check_all_empty_except_final (&info)) |
8e97bc2b | 1545 | { |
886cd84f SB |
1546 | gcc_assert (info.reason); |
1547 | return info.reason; | |
8e97bc2b | 1548 | } |
18bfe940 | 1549 | if (!check_final_bb (swtch, &info)) |
fade902a SB |
1550 | { |
1551 | gcc_assert (info.reason); | |
1552 | return info.reason; | |
1553 | } | |
b6e99746 MJ |
1554 | |
1555 | /* At this point all checks have passed and we can proceed with the | |
1556 | transformation. */ | |
1557 | ||
fade902a | 1558 | create_temp_arrays (&info); |
18bfe940 JJ |
1559 | gather_default_values (info.default_case_nonstandard |
1560 | ? gimple_switch_label (swtch, 1) | |
1561 | : gimple_switch_default_label (swtch), &info); | |
fade902a | 1562 | build_constructors (swtch, &info); |
b6e99746 | 1563 | |
fade902a SB |
1564 | build_arrays (swtch, &info); /* Build the static arrays and assignments. */ |
1565 | gen_inbound_check (swtch, &info); /* Build the bounds check. */ | |
b6e99746 MJ |
1566 | |
1567 | /* Cleanup: */ | |
fade902a SB |
1568 | free_temp_arrays (&info); |
1569 | return NULL; | |
b6e99746 MJ |
1570 | } |
1571 | ||
1572 | /* The main function of the pass scans statements for switches and invokes | |
1573 | process_switch on them. */ | |
1574 | ||
be55bfe6 TS |
1575 | namespace { |
1576 | ||
1577 | const pass_data pass_data_convert_switch = | |
1578 | { | |
1579 | GIMPLE_PASS, /* type */ | |
1580 | "switchconv", /* name */ | |
1581 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
1582 | TV_TREE_SWITCH_CONVERSION, /* tv_id */ |
1583 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1584 | 0, /* properties_provided */ | |
1585 | 0, /* properties_destroyed */ | |
1586 | 0, /* todo_flags_start */ | |
3bea341f | 1587 | TODO_update_ssa, /* todo_flags_finish */ |
be55bfe6 TS |
1588 | }; |
1589 | ||
1590 | class pass_convert_switch : public gimple_opt_pass | |
1591 | { | |
1592 | public: | |
1593 | pass_convert_switch (gcc::context *ctxt) | |
1594 | : gimple_opt_pass (pass_data_convert_switch, ctxt) | |
1595 | {} | |
1596 | ||
1597 | /* opt_pass methods: */ | |
1598 | virtual bool gate (function *) { return flag_tree_switch_conversion != 0; } | |
1599 | virtual unsigned int execute (function *); | |
1600 | ||
1601 | }; // class pass_convert_switch | |
1602 | ||
1603 | unsigned int | |
1604 | pass_convert_switch::execute (function *fun) | |
b6e99746 MJ |
1605 | { |
1606 | basic_block bb; | |
1607 | ||
be55bfe6 | 1608 | FOR_EACH_BB_FN (bb, fun) |
b6e99746 | 1609 | { |
fade902a | 1610 | const char *failure_reason; |
355fe088 | 1611 | gimple *stmt = last_stmt (bb); |
726a989a | 1612 | if (stmt && gimple_code (stmt) == GIMPLE_SWITCH) |
b6e99746 | 1613 | { |
b6e99746 MJ |
1614 | if (dump_file) |
1615 | { | |
726a989a RB |
1616 | expanded_location loc = expand_location (gimple_location (stmt)); |
1617 | ||
b6e99746 MJ |
1618 | fprintf (dump_file, "beginning to process the following " |
1619 | "SWITCH statement (%s:%d) : ------- \n", | |
1620 | loc.file, loc.line); | |
726a989a | 1621 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
edb30094 | 1622 | putc ('\n', dump_file); |
b6e99746 MJ |
1623 | } |
1624 | ||
538dd0b7 | 1625 | failure_reason = process_switch (as_a <gswitch *> (stmt)); |
fade902a | 1626 | if (! failure_reason) |
b6e99746 MJ |
1627 | { |
1628 | if (dump_file) | |
1629 | { | |
edb30094 UB |
1630 | fputs ("Switch converted\n", dump_file); |
1631 | fputs ("--------------------------------\n", dump_file); | |
b6e99746 | 1632 | } |
531b10fc SB |
1633 | |
1634 | /* Make no effort to update the post-dominator tree. It is actually not | |
1635 | that hard for the transformations we have performed, but it is not | |
1636 | supported by iterate_fix_dominators. */ | |
1637 | free_dominance_info (CDI_POST_DOMINATORS); | |
b6e99746 MJ |
1638 | } |
1639 | else | |
1640 | { | |
1641 | if (dump_file) | |
1642 | { | |
edb30094 | 1643 | fputs ("Bailing out - ", dump_file); |
fade902a SB |
1644 | fputs (failure_reason, dump_file); |
1645 | fputs ("\n--------------------------------\n", dump_file); | |
b6e99746 MJ |
1646 | } |
1647 | } | |
1648 | } | |
1649 | } | |
1650 | ||
1651 | return 0; | |
1652 | } | |
1653 | ||
27a4cd48 DM |
1654 | } // anon namespace |
1655 | ||
1656 | gimple_opt_pass * | |
1657 | make_pass_convert_switch (gcc::context *ctxt) | |
1658 | { | |
1659 | return new pass_convert_switch (ctxt); | |
1660 | } | |
9dc3d6a9 ML |
1661 | |
1662 | struct case_node | |
1663 | { | |
1664 | case_node *left; /* Left son in binary tree. */ | |
1665 | case_node *right; /* Right son in binary tree; | |
1666 | also node chain. */ | |
1667 | case_node *parent; /* Parent of node in binary tree. */ | |
1668 | tree low; /* Lowest index value for this label. */ | |
1669 | tree high; /* Highest index value for this label. */ | |
1670 | basic_block case_bb; /* Label to jump to when node matches. */ | |
1671 | tree case_label; /* Label to jump to when node matches. */ | |
1672 | profile_probability prob; /* Probability of taking this case. */ | |
1673 | profile_probability subtree_prob; /* Probability of reaching subtree | |
1674 | rooted at this node. */ | |
1675 | }; | |
1676 | ||
1677 | typedef case_node *case_node_ptr; | |
1678 | ||
1679 | static basic_block emit_case_nodes (basic_block, tree, case_node_ptr, | |
1680 | basic_block, tree, profile_probability, | |
1681 | tree, hash_map<tree, tree> *); | |
1682 | static bool node_has_low_bound (case_node_ptr, tree); | |
1683 | static bool node_has_high_bound (case_node_ptr, tree); | |
1684 | static bool node_is_bounded (case_node_ptr, tree); | |
1685 | ||
1686 | /* Return the smallest number of different values for which it is best to use a | |
1687 | jump-table instead of a tree of conditional branches. */ | |
1688 | ||
1689 | static unsigned int | |
1690 | case_values_threshold (void) | |
1691 | { | |
1692 | unsigned int threshold = PARAM_VALUE (PARAM_CASE_VALUES_THRESHOLD); | |
1693 | ||
1694 | if (threshold == 0) | |
1695 | threshold = targetm.case_values_threshold (); | |
1696 | ||
1697 | return threshold; | |
1698 | } | |
1699 | ||
1700 | /* Reset the aux field of all outgoing edges of basic block BB. */ | |
1701 | ||
1702 | static inline void | |
1703 | reset_out_edges_aux (basic_block bb) | |
1704 | { | |
1705 | edge e; | |
1706 | edge_iterator ei; | |
1707 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1708 | e->aux = (void *) 0; | |
1709 | } | |
1710 | ||
1711 | /* Compute the number of case labels that correspond to each outgoing edge of | |
1712 | STMT. Record this information in the aux field of the edge. */ | |
1713 | ||
1714 | static inline void | |
1715 | compute_cases_per_edge (gswitch *stmt) | |
1716 | { | |
1717 | basic_block bb = gimple_bb (stmt); | |
1718 | reset_out_edges_aux (bb); | |
1719 | int ncases = gimple_switch_num_labels (stmt); | |
1720 | for (int i = ncases - 1; i >= 1; --i) | |
1721 | { | |
1722 | tree elt = gimple_switch_label (stmt, i); | |
1723 | tree lab = CASE_LABEL (elt); | |
1724 | basic_block case_bb = label_to_block_fn (cfun, lab); | |
1725 | edge case_edge = find_edge (bb, case_bb); | |
1726 | case_edge->aux = (void *) ((intptr_t) (case_edge->aux) + 1); | |
1727 | } | |
1728 | } | |
1729 | ||
1730 | /* Do the insertion of a case label into case_list. The labels are | |
1731 | fed to us in descending order from the sorted vector of case labels used | |
1732 | in the tree part of the middle end. So the list we construct is | |
1733 | sorted in ascending order. | |
1734 | ||
1735 | LABEL is the case label to be inserted. LOW and HIGH are the bounds | |
1736 | against which the index is compared to jump to LABEL and PROB is the | |
1737 | estimated probability LABEL is reached from the switch statement. */ | |
1738 | ||
1739 | static case_node * | |
1740 | add_case_node (case_node *head, tree low, tree high, basic_block case_bb, | |
1741 | tree case_label, profile_probability prob, | |
1742 | object_allocator<case_node> &case_node_pool) | |
1743 | { | |
1744 | case_node *r; | |
1745 | ||
1746 | gcc_checking_assert (low); | |
1747 | gcc_checking_assert (high && (TREE_TYPE (low) == TREE_TYPE (high))); | |
1748 | ||
1749 | /* Add this label to the chain. */ | |
1750 | r = case_node_pool.allocate (); | |
1751 | r->low = low; | |
1752 | r->high = high; | |
1753 | r->case_bb = case_bb; | |
1754 | r->case_label = case_label; | |
1755 | r->parent = r->left = NULL; | |
1756 | r->prob = prob; | |
1757 | r->subtree_prob = prob; | |
1758 | r->right = head; | |
1759 | return r; | |
1760 | } | |
1761 | ||
1762 | /* Dump ROOT, a list or tree of case nodes, to file. */ | |
1763 | ||
1764 | static void | |
1765 | dump_case_nodes (FILE *f, case_node *root, int indent_step, int indent_level) | |
1766 | { | |
1767 | if (root == 0) | |
1768 | return; | |
1769 | indent_level++; | |
1770 | ||
1771 | dump_case_nodes (f, root->left, indent_step, indent_level); | |
1772 | ||
1773 | fputs (";; ", f); | |
1774 | fprintf (f, "%*s", indent_step * indent_level, ""); | |
8e6cdc90 | 1775 | print_dec (wi::to_wide (root->low), f, TYPE_SIGN (TREE_TYPE (root->low))); |
9dc3d6a9 ML |
1776 | if (!tree_int_cst_equal (root->low, root->high)) |
1777 | { | |
1778 | fprintf (f, " ... "); | |
8e6cdc90 RS |
1779 | print_dec (wi::to_wide (root->high), f, |
1780 | TYPE_SIGN (TREE_TYPE (root->high))); | |
9dc3d6a9 ML |
1781 | } |
1782 | fputs ("\n", f); | |
1783 | ||
1784 | dump_case_nodes (f, root->right, indent_step, indent_level); | |
1785 | } | |
1786 | ||
1787 | /* Take an ordered list of case nodes | |
1788 | and transform them into a near optimal binary tree, | |
1789 | on the assumption that any target code selection value is as | |
1790 | likely as any other. | |
1791 | ||
1792 | The transformation is performed by splitting the ordered | |
1793 | list into two equal sections plus a pivot. The parts are | |
1794 | then attached to the pivot as left and right branches. Each | |
1795 | branch is then transformed recursively. */ | |
1796 | ||
1797 | static void | |
1798 | balance_case_nodes (case_node_ptr *head, case_node_ptr parent) | |
1799 | { | |
1800 | case_node_ptr np; | |
1801 | ||
1802 | np = *head; | |
1803 | if (np) | |
1804 | { | |
1805 | int i = 0; | |
1806 | int ranges = 0; | |
1807 | case_node_ptr *npp; | |
1808 | case_node_ptr left; | |
1809 | ||
1810 | /* Count the number of entries on branch. Also count the ranges. */ | |
1811 | ||
1812 | while (np) | |
1813 | { | |
1814 | if (!tree_int_cst_equal (np->low, np->high)) | |
1815 | ranges++; | |
1816 | ||
1817 | i++; | |
1818 | np = np->right; | |
1819 | } | |
1820 | ||
1821 | if (i > 2) | |
1822 | { | |
1823 | /* Split this list if it is long enough for that to help. */ | |
1824 | npp = head; | |
1825 | left = *npp; | |
1826 | ||
1827 | /* If there are just three nodes, split at the middle one. */ | |
1828 | if (i == 3) | |
1829 | npp = &(*npp)->right; | |
1830 | else | |
1831 | { | |
1832 | /* Find the place in the list that bisects the list's total cost, | |
1833 | where ranges count as 2. | |
1834 | Here I gets half the total cost. */ | |
1835 | i = (i + ranges + 1) / 2; | |
1836 | while (1) | |
1837 | { | |
1838 | /* Skip nodes while their cost does not reach that amount. */ | |
1839 | if (!tree_int_cst_equal ((*npp)->low, (*npp)->high)) | |
1840 | i--; | |
1841 | i--; | |
1842 | if (i <= 0) | |
1843 | break; | |
1844 | npp = &(*npp)->right; | |
1845 | } | |
1846 | } | |
1847 | *head = np = *npp; | |
1848 | *npp = 0; | |
1849 | np->parent = parent; | |
1850 | np->left = left; | |
1851 | ||
1852 | /* Optimize each of the two split parts. */ | |
1853 | balance_case_nodes (&np->left, np); | |
1854 | balance_case_nodes (&np->right, np); | |
1855 | np->subtree_prob = np->prob; | |
1856 | np->subtree_prob += np->left->subtree_prob; | |
1857 | np->subtree_prob += np->right->subtree_prob; | |
1858 | } | |
1859 | else | |
1860 | { | |
1861 | /* Else leave this branch as one level, | |
1862 | but fill in `parent' fields. */ | |
1863 | np = *head; | |
1864 | np->parent = parent; | |
1865 | np->subtree_prob = np->prob; | |
1866 | for (; np->right; np = np->right) | |
1867 | { | |
1868 | np->right->parent = np; | |
1869 | (*head)->subtree_prob += np->right->subtree_prob; | |
1870 | } | |
1871 | } | |
1872 | } | |
1873 | } | |
1874 | ||
1875 | /* Return true if a switch should be expanded as a decision tree. | |
1876 | RANGE is the difference between highest and lowest case. | |
1877 | UNIQ is number of unique case node targets, not counting the default case. | |
1878 | COUNT is the number of comparisons needed, not counting the default case. */ | |
1879 | ||
1880 | static bool | |
1881 | expand_switch_as_decision_tree_p (tree range, | |
1882 | unsigned int uniq ATTRIBUTE_UNUSED, | |
1883 | unsigned int count) | |
1884 | { | |
1885 | int max_ratio; | |
1886 | ||
1887 | /* If neither casesi or tablejump is available, or flag_jump_tables | |
1888 | over-ruled us, we really have no choice. */ | |
1889 | if (!targetm.have_casesi () && !targetm.have_tablejump ()) | |
1890 | return true; | |
1891 | if (!flag_jump_tables) | |
1892 | return true; | |
1893 | #ifndef ASM_OUTPUT_ADDR_DIFF_ELT | |
1894 | if (flag_pic) | |
1895 | return true; | |
1896 | #endif | |
1897 | ||
1898 | /* If the switch is relatively small such that the cost of one | |
1899 | indirect jump on the target are higher than the cost of a | |
1900 | decision tree, go with the decision tree. | |
1901 | ||
1902 | If range of values is much bigger than number of values, | |
1903 | or if it is too large to represent in a HOST_WIDE_INT, | |
1904 | make a sequence of conditional branches instead of a dispatch. | |
1905 | ||
1906 | The definition of "much bigger" depends on whether we are | |
1907 | optimizing for size or for speed. If the former, the maximum | |
1908 | ratio range/count = 3, because this was found to be the optimal | |
1909 | ratio for size on i686-pc-linux-gnu, see PR11823. The ratio | |
1910 | 10 is much older, and was probably selected after an extensive | |
1911 | benchmarking investigation on numerous platforms. Or maybe it | |
1912 | just made sense to someone at some point in the history of GCC, | |
1913 | who knows... */ | |
1914 | max_ratio = optimize_insn_for_size_p () ? 3 : 10; | |
1915 | if (count < case_values_threshold () || !tree_fits_uhwi_p (range) | |
1916 | || compare_tree_int (range, max_ratio * count) > 0) | |
1917 | return true; | |
1918 | ||
1919 | return false; | |
1920 | } | |
1921 | ||
1922 | static void | |
1923 | fix_phi_operands_for_edge (edge e, hash_map<tree, tree> *phi_mapping) | |
1924 | { | |
1925 | basic_block bb = e->dest; | |
1926 | gphi_iterator gsi; | |
1927 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
1928 | { | |
1929 | gphi *phi = gsi.phi (); | |
1930 | ||
1931 | tree *definition = phi_mapping->get (gimple_phi_result (phi)); | |
1932 | if (definition) | |
1933 | add_phi_arg (phi, *definition, e, UNKNOWN_LOCATION); | |
1934 | } | |
1935 | } | |
1936 | ||
1937 | ||
1938 | /* Add an unconditional jump to CASE_BB that happens in basic block BB. */ | |
1939 | ||
1940 | static void | |
1941 | emit_jump (basic_block bb, basic_block case_bb, | |
1942 | hash_map<tree, tree> *phi_mapping) | |
1943 | { | |
1944 | edge e = single_succ_edge (bb); | |
1945 | redirect_edge_succ (e, case_bb); | |
1946 | fix_phi_operands_for_edge (e, phi_mapping); | |
1947 | } | |
1948 | ||
1949 | /* Generate a decision tree, switching on INDEX_EXPR and jumping to | |
1950 | one of the labels in CASE_LIST or to the DEFAULT_LABEL. | |
1951 | DEFAULT_PROB is the estimated probability that it jumps to | |
1952 | DEFAULT_LABEL. | |
1953 | ||
1954 | We generate a binary decision tree to select the appropriate target | |
1955 | code. */ | |
1956 | ||
1957 | static void | |
1958 | emit_case_decision_tree (gswitch *s, tree index_expr, tree index_type, | |
1959 | case_node_ptr case_list, basic_block default_bb, | |
1960 | tree default_label, profile_probability default_prob, | |
1961 | hash_map<tree, tree> *phi_mapping) | |
1962 | { | |
1963 | balance_case_nodes (&case_list, NULL); | |
1964 | ||
1965 | if (dump_file) | |
1966 | dump_function_to_file (current_function_decl, dump_file, dump_flags); | |
1967 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
1968 | { | |
1969 | int indent_step = ceil_log2 (TYPE_PRECISION (index_type)) + 2; | |
1970 | fprintf (dump_file, ";; Expanding GIMPLE switch as decision tree:\n"); | |
1971 | dump_case_nodes (dump_file, case_list, indent_step, 0); | |
1972 | } | |
1973 | ||
1974 | basic_block bb = gimple_bb (s); | |
1975 | gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
1976 | edge e; | |
1977 | if (gsi_end_p (gsi)) | |
1978 | e = split_block_after_labels (bb); | |
1979 | else | |
1980 | { | |
1981 | gsi_prev (&gsi); | |
1982 | e = split_block (bb, gsi_stmt (gsi)); | |
1983 | } | |
1984 | bb = split_edge (e); | |
1985 | ||
1986 | bb = emit_case_nodes (bb, index_expr, case_list, default_bb, default_label, | |
1987 | default_prob, index_type, phi_mapping); | |
1988 | ||
1989 | if (bb) | |
1990 | emit_jump (bb, default_bb, phi_mapping); | |
1991 | ||
1992 | /* Remove all edges and do just an edge that will reach default_bb. */ | |
1993 | gsi = gsi_last_bb (gimple_bb (s)); | |
1994 | gsi_remove (&gsi, true); | |
1995 | } | |
1996 | ||
1997 | static void | |
1998 | record_phi_operand_mapping (const vec<basic_block> bbs, basic_block switch_bb, | |
1999 | hash_map <tree, tree> *map) | |
2000 | { | |
2001 | /* Record all PHI nodes that have to be fixed after conversion. */ | |
2002 | for (unsigned i = 0; i < bbs.length (); i++) | |
2003 | { | |
2004 | basic_block bb = bbs[i]; | |
2005 | ||
2006 | gphi_iterator gsi; | |
2007 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
2008 | { | |
2009 | gphi *phi = gsi.phi (); | |
2010 | ||
2011 | for (unsigned i = 0; i < gimple_phi_num_args (phi); i++) | |
2012 | { | |
2013 | basic_block phi_src_bb = gimple_phi_arg_edge (phi, i)->src; | |
2014 | if (phi_src_bb == switch_bb) | |
2015 | { | |
2016 | tree def = gimple_phi_arg_def (phi, i); | |
2017 | tree result = gimple_phi_result (phi); | |
2018 | map->put (result, def); | |
2019 | break; | |
2020 | } | |
2021 | } | |
2022 | } | |
2023 | } | |
2024 | } | |
2025 | ||
2026 | /* Attempt to expand gimple switch STMT to a decision tree. */ | |
2027 | ||
2028 | static bool | |
2029 | try_switch_expansion (gswitch *stmt) | |
2030 | { | |
2031 | tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE; | |
2032 | basic_block default_bb; | |
2033 | unsigned int count, uniq; | |
2034 | int i; | |
2035 | int ncases = gimple_switch_num_labels (stmt); | |
2036 | tree index_expr = gimple_switch_index (stmt); | |
2037 | tree index_type = TREE_TYPE (index_expr); | |
2038 | tree elt; | |
2039 | basic_block bb = gimple_bb (stmt); | |
2040 | ||
2041 | hash_map<tree, tree> phi_mapping; | |
2042 | auto_vec<basic_block> case_bbs; | |
2043 | ||
2044 | /* A list of case labels; it is first built as a list and it may then | |
2045 | be rearranged into a nearly balanced binary tree. */ | |
2046 | case_node *case_list = 0; | |
2047 | ||
2048 | /* A pool for case nodes. */ | |
2049 | object_allocator<case_node> case_node_pool ("struct case_node pool"); | |
2050 | ||
2051 | /* cleanup_tree_cfg removes all SWITCH_EXPR with their index | |
2052 | expressions being INTEGER_CST. */ | |
2053 | gcc_assert (TREE_CODE (index_expr) != INTEGER_CST); | |
2054 | ||
02e637d8 ML |
2055 | if (ncases == 1) |
2056 | return false; | |
9dc3d6a9 ML |
2057 | |
2058 | /* Find the default case target label. */ | |
2059 | tree default_label = CASE_LABEL (gimple_switch_default_label (stmt)); | |
2060 | default_bb = label_to_block_fn (cfun, default_label); | |
2061 | edge default_edge = find_edge (bb, default_bb); | |
2062 | profile_probability default_prob = default_edge->probability; | |
2063 | case_bbs.safe_push (default_bb); | |
2064 | ||
2065 | /* Get upper and lower bounds of case values. */ | |
2066 | elt = gimple_switch_label (stmt, 1); | |
2067 | minval = fold_convert (index_type, CASE_LOW (elt)); | |
2068 | elt = gimple_switch_label (stmt, ncases - 1); | |
2069 | if (CASE_HIGH (elt)) | |
2070 | maxval = fold_convert (index_type, CASE_HIGH (elt)); | |
2071 | else | |
2072 | maxval = fold_convert (index_type, CASE_LOW (elt)); | |
2073 | ||
2074 | /* Compute span of values. */ | |
2075 | range = fold_build2 (MINUS_EXPR, index_type, maxval, minval); | |
2076 | ||
2077 | /* Listify the labels queue and gather some numbers to decide | |
2078 | how to expand this switch. */ | |
2079 | uniq = 0; | |
2080 | count = 0; | |
2081 | hash_set<tree> seen_labels; | |
2082 | compute_cases_per_edge (stmt); | |
2083 | ||
2084 | for (i = ncases - 1; i >= 1; --i) | |
2085 | { | |
2086 | elt = gimple_switch_label (stmt, i); | |
2087 | tree low = CASE_LOW (elt); | |
2088 | gcc_assert (low); | |
2089 | tree high = CASE_HIGH (elt); | |
2090 | gcc_assert (!high || tree_int_cst_lt (low, high)); | |
2091 | tree lab = CASE_LABEL (elt); | |
2092 | ||
2093 | /* Count the elements. | |
2094 | A range counts double, since it requires two compares. */ | |
2095 | count++; | |
2096 | if (high) | |
2097 | count++; | |
2098 | ||
2099 | /* If we have not seen this label yet, then increase the | |
2100 | number of unique case node targets seen. */ | |
2101 | if (!seen_labels.add (lab)) | |
2102 | uniq++; | |
2103 | ||
2104 | /* The bounds on the case range, LOW and HIGH, have to be converted | |
2105 | to case's index type TYPE. Note that the original type of the | |
2106 | case index in the source code is usually "lost" during | |
2107 | gimplification due to type promotion, but the case labels retain the | |
2108 | original type. Make sure to drop overflow flags. */ | |
2109 | low = fold_convert (index_type, low); | |
2110 | if (TREE_OVERFLOW (low)) | |
8e6cdc90 | 2111 | low = wide_int_to_tree (index_type, wi::to_wide (low)); |
9dc3d6a9 ML |
2112 | |
2113 | /* The canonical from of a case label in GIMPLE is that a simple case | |
2114 | has an empty CASE_HIGH. For the casesi and tablejump expanders, | |
2115 | the back ends want simple cases to have high == low. */ | |
2116 | if (!high) | |
2117 | high = low; | |
2118 | high = fold_convert (index_type, high); | |
2119 | if (TREE_OVERFLOW (high)) | |
8e6cdc90 | 2120 | high = wide_int_to_tree (index_type, wi::to_wide (high)); |
9dc3d6a9 ML |
2121 | |
2122 | basic_block case_bb = label_to_block_fn (cfun, lab); | |
2123 | edge case_edge = find_edge (bb, case_bb); | |
2124 | case_list = add_case_node ( | |
2125 | case_list, low, high, case_bb, lab, | |
2126 | case_edge->probability.apply_scale (1, (intptr_t) (case_edge->aux)), | |
2127 | case_node_pool); | |
2128 | ||
2129 | case_bbs.safe_push (case_bb); | |
2130 | } | |
2131 | reset_out_edges_aux (bb); | |
2132 | record_phi_operand_mapping (case_bbs, bb, &phi_mapping); | |
2133 | ||
2134 | /* cleanup_tree_cfg removes all SWITCH_EXPR with a single | |
2135 | destination, such as one with a default case only. | |
2136 | It also removes cases that are out of range for the switch | |
2137 | type, so we should never get a zero here. */ | |
2138 | gcc_assert (count > 0); | |
2139 | ||
2140 | /* Decide how to expand this switch. | |
2141 | The two options at this point are a dispatch table (casesi or | |
2142 | tablejump) or a decision tree. */ | |
2143 | ||
2144 | if (expand_switch_as_decision_tree_p (range, uniq, count)) | |
2145 | { | |
2146 | emit_case_decision_tree (stmt, index_expr, index_type, case_list, | |
2147 | default_bb, default_label, default_prob, | |
2148 | &phi_mapping); | |
2149 | return true; | |
2150 | } | |
2151 | ||
2152 | return false; | |
2153 | } | |
2154 | ||
2155 | /* The main function of the pass scans statements for switches and invokes | |
2156 | process_switch on them. */ | |
2157 | ||
2158 | namespace { | |
2159 | ||
2160 | const pass_data pass_data_lower_switch = | |
2161 | { | |
2162 | GIMPLE_PASS, /* type */ | |
2163 | "switchlower", /* name */ | |
2164 | OPTGROUP_NONE, /* optinfo_flags */ | |
2165 | TV_TREE_SWITCH_LOWERING, /* tv_id */ | |
2166 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
2167 | 0, /* properties_provided */ | |
2168 | 0, /* properties_destroyed */ | |
2169 | 0, /* todo_flags_start */ | |
2170 | TODO_update_ssa | TODO_cleanup_cfg, /* todo_flags_finish */ | |
2171 | }; | |
2172 | ||
2173 | class pass_lower_switch : public gimple_opt_pass | |
2174 | { | |
2175 | public: | |
2176 | pass_lower_switch (gcc::context *ctxt) | |
2177 | : gimple_opt_pass (pass_data_lower_switch, ctxt) | |
2178 | {} | |
2179 | ||
2180 | /* opt_pass methods: */ | |
2181 | virtual bool gate (function *) { return true; } | |
2182 | virtual unsigned int execute (function *); | |
2183 | ||
2184 | }; // class pass_lower_switch | |
2185 | ||
2186 | unsigned int | |
2187 | pass_lower_switch::execute (function *fun) | |
2188 | { | |
2189 | basic_block bb; | |
2190 | bool expanded = false; | |
2191 | ||
2192 | FOR_EACH_BB_FN (bb, fun) | |
2193 | { | |
2194 | gimple *stmt = last_stmt (bb); | |
2195 | if (stmt && gimple_code (stmt) == GIMPLE_SWITCH) | |
2196 | { | |
2197 | if (dump_file) | |
2198 | { | |
2199 | expanded_location loc = expand_location (gimple_location (stmt)); | |
2200 | ||
2201 | fprintf (dump_file, "beginning to process the following " | |
2202 | "SWITCH statement (%s:%d) : ------- \n", | |
2203 | loc.file, loc.line); | |
2204 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
2205 | putc ('\n', dump_file); | |
2206 | } | |
2207 | ||
2208 | expanded |= try_switch_expansion (as_a<gswitch *> (stmt)); | |
2209 | } | |
2210 | } | |
2211 | ||
2212 | if (expanded) | |
2213 | { | |
2214 | free_dominance_info (CDI_DOMINATORS); | |
2215 | free_dominance_info (CDI_POST_DOMINATORS); | |
2216 | mark_virtual_operands_for_renaming (cfun); | |
2217 | } | |
2218 | ||
2219 | return 0; | |
2220 | } | |
2221 | ||
2222 | } // anon namespace | |
2223 | ||
2224 | gimple_opt_pass * | |
2225 | make_pass_lower_switch (gcc::context *ctxt) | |
2226 | { | |
2227 | return new pass_lower_switch (ctxt); | |
2228 | } | |
2229 | ||
2230 | /* Generate code to jump to LABEL if OP0 and OP1 are equal in mode MODE. | |
2231 | PROB is the probability of jumping to LABEL. */ | |
2232 | static basic_block | |
2233 | do_jump_if_equal (basic_block bb, tree op0, tree op1, basic_block label_bb, | |
2234 | profile_probability prob, hash_map<tree, tree> *phi_mapping) | |
2235 | { | |
2236 | gcond *cond = gimple_build_cond (EQ_EXPR, op0, op1, NULL_TREE, NULL_TREE); | |
2237 | gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
2238 | gsi_insert_before (&gsi, cond, GSI_SAME_STMT); | |
2239 | ||
2240 | gcc_assert (single_succ_p (bb)); | |
2241 | ||
2242 | /* Make a new basic block where false branch will take place. */ | |
2243 | edge false_edge = split_block (bb, cond); | |
2244 | false_edge->flags = EDGE_FALSE_VALUE; | |
2245 | false_edge->probability = prob.invert (); | |
2246 | ||
2247 | edge true_edge = make_edge (bb, label_bb, EDGE_TRUE_VALUE); | |
2248 | fix_phi_operands_for_edge (true_edge, phi_mapping); | |
2249 | true_edge->probability = prob; | |
2250 | ||
2251 | return false_edge->dest; | |
2252 | } | |
2253 | ||
2254 | /* Generate code to compare X with Y so that the condition codes are | |
2255 | set and to jump to LABEL if the condition is true. If X is a | |
2256 | constant and Y is not a constant, then the comparison is swapped to | |
2257 | ensure that the comparison RTL has the canonical form. | |
2258 | ||
2259 | UNSIGNEDP nonzero says that X and Y are unsigned; this matters if they | |
2260 | need to be widened. UNSIGNEDP is also used to select the proper | |
2261 | branch condition code. | |
2262 | ||
2263 | If X and Y have mode BLKmode, then SIZE specifies the size of both X and Y. | |
2264 | ||
2265 | MODE is the mode of the inputs (in case they are const_int). | |
2266 | ||
2267 | COMPARISON is the rtl operator to compare with (EQ, NE, GT, etc.). | |
2268 | It will be potentially converted into an unsigned variant based on | |
2269 | UNSIGNEDP to select a proper jump instruction. | |
2270 | ||
2271 | PROB is the probability of jumping to LABEL. */ | |
2272 | ||
2273 | static basic_block | |
2274 | emit_cmp_and_jump_insns (basic_block bb, tree op0, tree op1, | |
2275 | tree_code comparison, basic_block label_bb, | |
2276 | profile_probability prob, | |
2277 | hash_map<tree, tree> *phi_mapping) | |
2278 | { | |
2279 | gcond *cond = gimple_build_cond (comparison, op0, op1, NULL_TREE, NULL_TREE); | |
2280 | gimple_stmt_iterator gsi = gsi_last_bb (bb); | |
2281 | gsi_insert_after (&gsi, cond, GSI_NEW_STMT); | |
2282 | ||
2283 | gcc_assert (single_succ_p (bb)); | |
2284 | ||
2285 | /* Make a new basic block where false branch will take place. */ | |
2286 | edge false_edge = split_block (bb, cond); | |
2287 | false_edge->flags = EDGE_FALSE_VALUE; | |
2288 | false_edge->probability = prob.invert (); | |
2289 | ||
2290 | edge true_edge = make_edge (bb, label_bb, EDGE_TRUE_VALUE); | |
2291 | fix_phi_operands_for_edge (true_edge, phi_mapping); | |
2292 | true_edge->probability = prob; | |
2293 | ||
2294 | return false_edge->dest; | |
2295 | } | |
2296 | ||
2297 | /* Computes the conditional probability of jumping to a target if the branch | |
2298 | instruction is executed. | |
2299 | TARGET_PROB is the estimated probability of jumping to a target relative | |
2300 | to some basic block BB. | |
2301 | BASE_PROB is the probability of reaching the branch instruction relative | |
2302 | to the same basic block BB. */ | |
2303 | ||
2304 | static inline profile_probability | |
2305 | conditional_probability (profile_probability target_prob, | |
2306 | profile_probability base_prob) | |
2307 | { | |
2308 | return target_prob / base_prob; | |
2309 | } | |
2310 | ||
2311 | /* Emit step-by-step code to select a case for the value of INDEX. | |
2312 | The thus generated decision tree follows the form of the | |
2313 | case-node binary tree NODE, whose nodes represent test conditions. | |
2314 | INDEX_TYPE is the type of the index of the switch. | |
2315 | ||
2316 | Care is taken to prune redundant tests from the decision tree | |
2317 | by detecting any boundary conditions already checked by | |
2318 | emitted rtx. (See node_has_high_bound, node_has_low_bound | |
2319 | and node_is_bounded, above.) | |
2320 | ||
2321 | Where the test conditions can be shown to be redundant we emit | |
2322 | an unconditional jump to the target code. As a further | |
2323 | optimization, the subordinates of a tree node are examined to | |
2324 | check for bounded nodes. In this case conditional and/or | |
2325 | unconditional jumps as a result of the boundary check for the | |
2326 | current node are arranged to target the subordinates associated | |
2327 | code for out of bound conditions on the current node. | |
2328 | ||
2329 | We can assume that when control reaches the code generated here, | |
2330 | the index value has already been compared with the parents | |
2331 | of this node, and determined to be on the same side of each parent | |
2332 | as this node is. Thus, if this node tests for the value 51, | |
2333 | and a parent tested for 52, we don't need to consider | |
2334 | the possibility of a value greater than 51. If another parent | |
2335 | tests for the value 50, then this node need not test anything. */ | |
2336 | ||
2337 | static basic_block | |
2338 | emit_case_nodes (basic_block bb, tree index, case_node_ptr node, | |
2339 | basic_block default_bb, tree default_label, | |
2340 | profile_probability default_prob, tree index_type, | |
2341 | hash_map<tree, tree> *phi_mapping) | |
2342 | { | |
2343 | /* If INDEX has an unsigned type, we must make unsigned branches. */ | |
2344 | profile_probability probability; | |
2345 | profile_probability prob = node->prob, subtree_prob = node->subtree_prob; | |
2346 | ||
2347 | /* See if our parents have already tested everything for us. | |
2348 | If they have, emit an unconditional jump for this node. */ | |
2349 | if (node_is_bounded (node, index_type)) | |
2350 | { | |
2351 | emit_jump (bb, node->case_bb, phi_mapping); | |
2352 | return NULL; | |
2353 | } | |
2354 | ||
2355 | else if (tree_int_cst_equal (node->low, node->high)) | |
2356 | { | |
2357 | probability = conditional_probability (prob, subtree_prob + default_prob); | |
2358 | /* Node is single valued. First see if the index expression matches | |
2359 | this node and then check our children, if any. */ | |
2360 | bb = do_jump_if_equal (bb, index, node->low, node->case_bb, probability, | |
2361 | phi_mapping); | |
2362 | /* Since this case is taken at this point, reduce its weight from | |
2363 | subtree_weight. */ | |
2364 | subtree_prob -= prob; | |
2365 | if (node->right != 0 && node->left != 0) | |
2366 | { | |
2367 | /* This node has children on both sides. | |
2368 | Dispatch to one side or the other | |
2369 | by comparing the index value with this node's value. | |
2370 | If one subtree is bounded, check that one first, | |
2371 | so we can avoid real branches in the tree. */ | |
2372 | ||
2373 | if (node_is_bounded (node->right, index_type)) | |
2374 | { | |
2375 | probability | |
2376 | = conditional_probability (node->right->prob, | |
2377 | subtree_prob + default_prob); | |
2378 | bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
2379 | node->right->case_bb, probability, | |
2380 | phi_mapping); | |
2381 | bb = emit_case_nodes (bb, index, node->left, default_bb, | |
2382 | default_label, default_prob, index_type, | |
2383 | phi_mapping); | |
2384 | } | |
2385 | ||
2386 | else if (node_is_bounded (node->left, index_type)) | |
2387 | { | |
2388 | probability | |
2389 | = conditional_probability (node->left->prob, | |
2390 | subtree_prob + default_prob); | |
2391 | bb = emit_cmp_and_jump_insns (bb, index, node->high, LT_EXPR, | |
2392 | node->left->case_bb, probability, | |
2393 | phi_mapping); | |
2394 | bb = emit_case_nodes (bb, index, node->right, default_bb, | |
2395 | default_label, default_prob, index_type, | |
2396 | phi_mapping); | |
2397 | } | |
2398 | ||
2399 | /* If both children are single-valued cases with no | |
2400 | children, finish up all the work. This way, we can save | |
2401 | one ordered comparison. */ | |
2402 | else if (tree_int_cst_equal (node->right->low, node->right->high) | |
2403 | && node->right->left == 0 && node->right->right == 0 | |
2404 | && tree_int_cst_equal (node->left->low, node->left->high) | |
2405 | && node->left->left == 0 && node->left->right == 0) | |
2406 | { | |
2407 | /* Neither node is bounded. First distinguish the two sides; | |
2408 | then emit the code for one side at a time. */ | |
2409 | ||
2410 | /* See if the value matches what the right hand side | |
2411 | wants. */ | |
2412 | probability | |
2413 | = conditional_probability (node->right->prob, | |
2414 | subtree_prob + default_prob); | |
2415 | bb = do_jump_if_equal (bb, index, node->right->low, | |
2416 | node->right->case_bb, probability, | |
2417 | phi_mapping); | |
2418 | ||
2419 | /* See if the value matches what the left hand side | |
2420 | wants. */ | |
2421 | probability | |
2422 | = conditional_probability (node->left->prob, | |
2423 | subtree_prob + default_prob); | |
2424 | bb = do_jump_if_equal (bb, index, node->left->low, | |
2425 | node->left->case_bb, probability, | |
2426 | phi_mapping); | |
2427 | } | |
2428 | ||
2429 | else | |
2430 | { | |
2431 | /* Neither node is bounded. First distinguish the two sides; | |
2432 | then emit the code for one side at a time. */ | |
2433 | ||
2434 | basic_block test_bb = split_edge (single_succ_edge (bb)); | |
2435 | redirect_edge_succ (single_pred_edge (test_bb), | |
2436 | single_succ_edge (bb)->dest); | |
2437 | ||
2438 | /* The default label could be reached either through the right | |
2439 | subtree or the left subtree. Divide the probability | |
2440 | equally. */ | |
2441 | probability | |
2442 | = conditional_probability (node->right->subtree_prob | |
2443 | + default_prob.apply_scale (1, 2), | |
2444 | subtree_prob + default_prob); | |
2445 | /* See if the value is on the right. */ | |
2446 | bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
2447 | test_bb, probability, phi_mapping); | |
2448 | default_prob = default_prob.apply_scale (1, 2); | |
2449 | ||
2450 | /* Value must be on the left. | |
2451 | Handle the left-hand subtree. */ | |
2452 | bb = emit_case_nodes (bb, index, node->left, default_bb, | |
2453 | default_label, default_prob, index_type, | |
2454 | phi_mapping); | |
2455 | /* If left-hand subtree does nothing, | |
2456 | go to default. */ | |
2457 | ||
2458 | if (bb && default_bb) | |
2459 | emit_jump (bb, default_bb, phi_mapping); | |
2460 | ||
2461 | /* Code branches here for the right-hand subtree. */ | |
2462 | bb = emit_case_nodes (test_bb, index, node->right, default_bb, | |
2463 | default_label, default_prob, index_type, | |
2464 | phi_mapping); | |
2465 | } | |
2466 | } | |
2467 | else if (node->right != 0 && node->left == 0) | |
2468 | { | |
2469 | /* Here we have a right child but no left so we issue a conditional | |
2470 | branch to default and process the right child. | |
2471 | ||
2472 | Omit the conditional branch to default if the right child | |
2473 | does not have any children and is single valued; it would | |
2474 | cost too much space to save so little time. */ | |
2475 | ||
2476 | if (node->right->right || node->right->left | |
2477 | || !tree_int_cst_equal (node->right->low, node->right->high)) | |
2478 | { | |
2479 | if (!node_has_low_bound (node, index_type)) | |
2480 | { | |
2481 | probability | |
2482 | = conditional_probability (default_prob.apply_scale (1, 2), | |
2483 | subtree_prob + default_prob); | |
2484 | bb = emit_cmp_and_jump_insns (bb, index, node->high, LT_EXPR, | |
2485 | default_bb, probability, | |
2486 | phi_mapping); | |
2487 | default_prob = default_prob.apply_scale (1, 2); | |
2488 | } | |
2489 | ||
2490 | bb = emit_case_nodes (bb, index, node->right, default_bb, | |
2491 | default_label, default_prob, index_type, | |
2492 | phi_mapping); | |
2493 | } | |
2494 | else | |
2495 | { | |
2496 | probability | |
2497 | = conditional_probability (node->right->subtree_prob, | |
2498 | subtree_prob + default_prob); | |
2499 | /* We cannot process node->right normally | |
2500 | since we haven't ruled out the numbers less than | |
2501 | this node's value. So handle node->right explicitly. */ | |
2502 | bb = do_jump_if_equal (bb, index, node->right->low, | |
2503 | node->right->case_bb, probability, | |
2504 | phi_mapping); | |
2505 | } | |
2506 | } | |
2507 | ||
2508 | else if (node->right == 0 && node->left != 0) | |
2509 | { | |
2510 | /* Just one subtree, on the left. */ | |
2511 | if (node->left->left || node->left->right | |
2512 | || !tree_int_cst_equal (node->left->low, node->left->high)) | |
2513 | { | |
2514 | if (!node_has_high_bound (node, index_type)) | |
2515 | { | |
2516 | probability | |
2517 | = conditional_probability (default_prob.apply_scale (1, 2), | |
2518 | subtree_prob + default_prob); | |
2519 | bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
2520 | default_bb, probability, | |
2521 | phi_mapping); | |
2522 | default_prob = default_prob.apply_scale (1, 2); | |
2523 | } | |
2524 | ||
2525 | bb = emit_case_nodes (bb, index, node->left, default_bb, | |
2526 | default_label, default_prob, index_type, | |
2527 | phi_mapping); | |
2528 | } | |
2529 | else | |
2530 | { | |
2531 | probability | |
2532 | = conditional_probability (node->left->subtree_prob, | |
2533 | subtree_prob + default_prob); | |
2534 | /* We cannot process node->left normally | |
2535 | since we haven't ruled out the numbers less than | |
2536 | this node's value. So handle node->left explicitly. */ | |
2537 | do_jump_if_equal (bb, index, node->left->low, node->left->case_bb, | |
2538 | probability, phi_mapping); | |
2539 | } | |
2540 | } | |
2541 | } | |
2542 | else | |
2543 | { | |
2544 | /* Node is a range. These cases are very similar to those for a single | |
2545 | value, except that we do not start by testing whether this node | |
2546 | is the one to branch to. */ | |
2547 | ||
2548 | if (node->right != 0 && node->left != 0) | |
2549 | { | |
2550 | /* Node has subtrees on both sides. | |
2551 | If the right-hand subtree is bounded, | |
2552 | test for it first, since we can go straight there. | |
2553 | Otherwise, we need to make a branch in the control structure, | |
2554 | then handle the two subtrees. */ | |
2555 | basic_block test_bb = NULL; | |
2556 | ||
2557 | if (node_is_bounded (node->right, index_type)) | |
2558 | { | |
2559 | /* Right hand node is fully bounded so we can eliminate any | |
2560 | testing and branch directly to the target code. */ | |
2561 | probability | |
2562 | = conditional_probability (node->right->subtree_prob, | |
2563 | subtree_prob + default_prob); | |
2564 | bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
2565 | node->right->case_bb, probability, | |
2566 | phi_mapping); | |
2567 | } | |
2568 | else | |
2569 | { | |
2570 | /* Right hand node requires testing. | |
2571 | Branch to a label where we will handle it later. */ | |
2572 | ||
2573 | test_bb = split_edge (single_succ_edge (bb)); | |
2574 | redirect_edge_succ (single_pred_edge (test_bb), | |
2575 | single_succ_edge (bb)->dest); | |
2576 | ||
2577 | probability | |
2578 | = conditional_probability (node->right->subtree_prob | |
2579 | + default_prob.apply_scale (1, 2), | |
2580 | subtree_prob + default_prob); | |
2581 | bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
2582 | test_bb, probability, phi_mapping); | |
2583 | default_prob = default_prob.apply_scale (1, 2); | |
2584 | } | |
2585 | ||
2586 | /* Value belongs to this node or to the left-hand subtree. */ | |
2587 | ||
2588 | probability | |
2589 | = conditional_probability (prob, subtree_prob + default_prob); | |
2590 | bb = emit_cmp_and_jump_insns (bb, index, node->low, GE_EXPR, | |
2591 | node->case_bb, probability, | |
2592 | phi_mapping); | |
2593 | ||
2594 | /* Handle the left-hand subtree. */ | |
2595 | bb = emit_case_nodes (bb, index, node->left, default_bb, | |
2596 | default_label, default_prob, index_type, | |
2597 | phi_mapping); | |
2598 | ||
2599 | /* If right node had to be handled later, do that now. */ | |
2600 | if (test_bb) | |
2601 | { | |
2602 | /* If the left-hand subtree fell through, | |
2603 | don't let it fall into the right-hand subtree. */ | |
2604 | if (bb && default_bb) | |
2605 | emit_jump (bb, default_bb, phi_mapping); | |
2606 | ||
2607 | bb = emit_case_nodes (test_bb, index, node->right, default_bb, | |
2608 | default_label, default_prob, index_type, | |
2609 | phi_mapping); | |
2610 | } | |
2611 | } | |
2612 | ||
2613 | else if (node->right != 0 && node->left == 0) | |
2614 | { | |
2615 | /* Deal with values to the left of this node, | |
2616 | if they are possible. */ | |
2617 | if (!node_has_low_bound (node, index_type)) | |
2618 | { | |
2619 | probability | |
2620 | = conditional_probability (default_prob.apply_scale (1, 2), | |
2621 | subtree_prob + default_prob); | |
2622 | bb = emit_cmp_and_jump_insns (bb, index, node->low, LT_EXPR, | |
2623 | default_bb, probability, | |
2624 | phi_mapping); | |
2625 | default_prob = default_prob.apply_scale (1, 2); | |
2626 | } | |
2627 | ||
2628 | /* Value belongs to this node or to the right-hand subtree. */ | |
2629 | ||
2630 | probability | |
2631 | = conditional_probability (prob, subtree_prob + default_prob); | |
2632 | bb = emit_cmp_and_jump_insns (bb, index, node->high, LE_EXPR, | |
2633 | node->case_bb, probability, | |
2634 | phi_mapping); | |
2635 | ||
2636 | bb = emit_case_nodes (bb, index, node->right, default_bb, | |
2637 | default_label, default_prob, index_type, | |
2638 | phi_mapping); | |
2639 | } | |
2640 | ||
2641 | else if (node->right == 0 && node->left != 0) | |
2642 | { | |
2643 | /* Deal with values to the right of this node, | |
2644 | if they are possible. */ | |
2645 | if (!node_has_high_bound (node, index_type)) | |
2646 | { | |
2647 | probability | |
2648 | = conditional_probability (default_prob.apply_scale (1, 2), | |
2649 | subtree_prob + default_prob); | |
2650 | bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
2651 | default_bb, probability, | |
2652 | phi_mapping); | |
2653 | default_prob = default_prob.apply_scale (1, 2); | |
2654 | } | |
2655 | ||
2656 | /* Value belongs to this node or to the left-hand subtree. */ | |
2657 | ||
2658 | probability | |
2659 | = conditional_probability (prob, subtree_prob + default_prob); | |
2660 | bb = emit_cmp_and_jump_insns (bb, index, node->low, GE_EXPR, | |
2661 | node->case_bb, probability, | |
2662 | phi_mapping); | |
2663 | ||
2664 | bb = emit_case_nodes (bb, index, node->left, default_bb, | |
2665 | default_label, default_prob, index_type, | |
2666 | phi_mapping); | |
2667 | } | |
2668 | ||
2669 | else | |
2670 | { | |
2671 | /* Node has no children so we check low and high bounds to remove | |
2672 | redundant tests. Only one of the bounds can exist, | |
2673 | since otherwise this node is bounded--a case tested already. */ | |
2674 | bool high_bound = node_has_high_bound (node, index_type); | |
2675 | bool low_bound = node_has_low_bound (node, index_type); | |
2676 | ||
2677 | if (!high_bound && low_bound) | |
2678 | { | |
2679 | probability | |
2680 | = conditional_probability (default_prob, | |
2681 | subtree_prob + default_prob); | |
2682 | bb = emit_cmp_and_jump_insns (bb, index, node->high, GT_EXPR, | |
2683 | default_bb, probability, | |
2684 | phi_mapping); | |
2685 | } | |
2686 | ||
2687 | else if (!low_bound && high_bound) | |
2688 | { | |
2689 | probability | |
2690 | = conditional_probability (default_prob, | |
2691 | subtree_prob + default_prob); | |
2692 | bb = emit_cmp_and_jump_insns (bb, index, node->low, LT_EXPR, | |
2693 | default_bb, probability, | |
2694 | phi_mapping); | |
2695 | } | |
2696 | else if (!low_bound && !high_bound) | |
2697 | { | |
02e637d8 ML |
2698 | tree lhs, rhs; |
2699 | generate_range_test (bb, index, node->low, node->high, | |
2700 | &lhs, &rhs); | |
9dc3d6a9 ML |
2701 | probability |
2702 | = conditional_probability (default_prob, | |
2703 | subtree_prob + default_prob); | |
02e637d8 | 2704 | bb = emit_cmp_and_jump_insns (bb, lhs, rhs, GT_EXPR, |
9dc3d6a9 ML |
2705 | default_bb, probability, |
2706 | phi_mapping); | |
2707 | } | |
2708 | ||
2709 | emit_jump (bb, node->case_bb, phi_mapping); | |
2710 | return NULL; | |
2711 | } | |
2712 | } | |
2713 | ||
2714 | return bb; | |
2715 | } | |
2716 | ||
2717 | /* Search the parent sections of the case node tree | |
2718 | to see if a test for the lower bound of NODE would be redundant. | |
2719 | INDEX_TYPE is the type of the index expression. | |
2720 | ||
2721 | The instructions to generate the case decision tree are | |
2722 | output in the same order as nodes are processed so it is | |
2723 | known that if a parent node checks the range of the current | |
2724 | node minus one that the current node is bounded at its lower | |
2725 | span. Thus the test would be redundant. */ | |
2726 | ||
2727 | static bool | |
2728 | node_has_low_bound (case_node_ptr node, tree index_type) | |
2729 | { | |
2730 | tree low_minus_one; | |
2731 | case_node_ptr pnode; | |
2732 | ||
2733 | /* If the lower bound of this node is the lowest value in the index type, | |
2734 | we need not test it. */ | |
2735 | ||
2736 | if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type))) | |
2737 | return true; | |
2738 | ||
2739 | /* If this node has a left branch, the value at the left must be less | |
2740 | than that at this node, so it cannot be bounded at the bottom and | |
2741 | we need not bother testing any further. */ | |
2742 | ||
2743 | if (node->left) | |
2744 | return false; | |
2745 | ||
2746 | low_minus_one = fold_build2 (MINUS_EXPR, TREE_TYPE (node->low), node->low, | |
2747 | build_int_cst (TREE_TYPE (node->low), 1)); | |
2748 | ||
2749 | /* If the subtraction above overflowed, we can't verify anything. | |
2750 | Otherwise, look for a parent that tests our value - 1. */ | |
2751 | ||
2752 | if (!tree_int_cst_lt (low_minus_one, node->low)) | |
2753 | return false; | |
2754 | ||
2755 | for (pnode = node->parent; pnode; pnode = pnode->parent) | |
2756 | if (tree_int_cst_equal (low_minus_one, pnode->high)) | |
2757 | return true; | |
2758 | ||
2759 | return false; | |
2760 | } | |
2761 | ||
2762 | /* Search the parent sections of the case node tree | |
2763 | to see if a test for the upper bound of NODE would be redundant. | |
2764 | INDEX_TYPE is the type of the index expression. | |
2765 | ||
2766 | The instructions to generate the case decision tree are | |
2767 | output in the same order as nodes are processed so it is | |
2768 | known that if a parent node checks the range of the current | |
2769 | node plus one that the current node is bounded at its upper | |
2770 | span. Thus the test would be redundant. */ | |
2771 | ||
2772 | static bool | |
2773 | node_has_high_bound (case_node_ptr node, tree index_type) | |
2774 | { | |
2775 | tree high_plus_one; | |
2776 | case_node_ptr pnode; | |
2777 | ||
2778 | /* If there is no upper bound, obviously no test is needed. */ | |
2779 | ||
2780 | if (TYPE_MAX_VALUE (index_type) == NULL) | |
2781 | return true; | |
2782 | ||
2783 | /* If the upper bound of this node is the highest value in the type | |
2784 | of the index expression, we need not test against it. */ | |
2785 | ||
2786 | if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type))) | |
2787 | return true; | |
2788 | ||
2789 | /* If this node has a right branch, the value at the right must be greater | |
2790 | than that at this node, so it cannot be bounded at the top and | |
2791 | we need not bother testing any further. */ | |
2792 | ||
2793 | if (node->right) | |
2794 | return false; | |
2795 | ||
2796 | high_plus_one = fold_build2 (PLUS_EXPR, TREE_TYPE (node->high), node->high, | |
2797 | build_int_cst (TREE_TYPE (node->high), 1)); | |
2798 | ||
2799 | /* If the addition above overflowed, we can't verify anything. | |
2800 | Otherwise, look for a parent that tests our value + 1. */ | |
2801 | ||
2802 | if (!tree_int_cst_lt (node->high, high_plus_one)) | |
2803 | return false; | |
2804 | ||
2805 | for (pnode = node->parent; pnode; pnode = pnode->parent) | |
2806 | if (tree_int_cst_equal (high_plus_one, pnode->low)) | |
2807 | return true; | |
2808 | ||
2809 | return false; | |
2810 | } | |
2811 | ||
2812 | /* Search the parent sections of the | |
2813 | case node tree to see if both tests for the upper and lower | |
2814 | bounds of NODE would be redundant. */ | |
2815 | ||
2816 | static bool | |
2817 | node_is_bounded (case_node_ptr node, tree index_type) | |
2818 | { | |
2819 | return (node_has_low_bound (node, index_type) | |
2820 | && node_has_high_bound (node, index_type)); | |
2821 | } |