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531b10fc SB |
1 | /* Lower GIMPLE_SWITCH expressions to something more efficient than |
2 | a jump table. | |
23a5b65a | 3 | Copyright (C) 2006-2014 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" | |
28 | #include "tm.h" | |
29 | #include "line-map.h" | |
30 | #include "params.h" | |
31 | #include "flags.h" | |
32 | #include "tree.h" | |
d8a2d370 DN |
33 | #include "varasm.h" |
34 | #include "stor-layout.h" | |
60393bbc AM |
35 | #include "predict.h" |
36 | #include "vec.h" | |
37 | #include "hashtab.h" | |
38 | #include "hash-set.h" | |
39 | #include "machmode.h" | |
40 | #include "hard-reg-set.h" | |
41 | #include "input.h" | |
42 | #include "function.h" | |
43 | #include "dominance.h" | |
44 | #include "cfg.h" | |
45 | #include "cfganal.h" | |
531b10fc | 46 | #include "basic-block.h" |
2fb9a547 AM |
47 | #include "tree-ssa-alias.h" |
48 | #include "internal-fn.h" | |
49 | #include "gimple-expr.h" | |
50 | #include "is-a.h" | |
18f429e2 | 51 | #include "gimple.h" |
45b0be94 | 52 | #include "gimplify.h" |
5be5c238 | 53 | #include "gimple-iterator.h" |
18f429e2 | 54 | #include "gimplify-me.h" |
442b4905 | 55 | #include "gimple-ssa.h" |
c582198b AM |
56 | #include "hash-map.h" |
57 | #include "plugin-api.h" | |
58 | #include "ipa-ref.h" | |
442b4905 AM |
59 | #include "cgraph.h" |
60 | #include "tree-cfg.h" | |
61 | #include "tree-phinodes.h" | |
d8a2d370 | 62 | #include "stringpool.h" |
442b4905 | 63 | #include "tree-ssanames.h" |
531b10fc SB |
64 | #include "tree-pass.h" |
65 | #include "gimple-pretty-print.h" | |
a9e0d843 | 66 | #include "cfgloop.h" |
7ee2468b SB |
67 | |
68 | /* ??? For lang_hooks.types.type_for_mode, but is there a word_mode | |
69 | type in the GIMPLE type system that is language-independent? */ | |
531b10fc SB |
70 | #include "langhooks.h" |
71 | ||
72 | /* Need to include expr.h and optabs.h for lshift_cheap_p. */ | |
73 | #include "expr.h" | |
74 | #include "optabs.h" | |
75 | \f | |
76 | /* Maximum number of case bit tests. | |
77 | FIXME: This should be derived from PARAM_CASE_VALUES_THRESHOLD and | |
78 | targetm.case_values_threshold(), or be its own param. */ | |
79 | #define MAX_CASE_BIT_TESTS 3 | |
80 | ||
81 | /* Split the basic block at the statement pointed to by GSIP, and insert | |
82 | a branch to the target basic block of E_TRUE conditional on tree | |
83 | expression COND. | |
84 | ||
85 | It is assumed that there is already an edge from the to-be-split | |
86 | basic block to E_TRUE->dest block. This edge is removed, and the | |
87 | profile information on the edge is re-used for the new conditional | |
88 | jump. | |
89 | ||
90 | The CFG is updated. The dominator tree will not be valid after | |
91 | this transformation, but the immediate dominators are updated if | |
92 | UPDATE_DOMINATORS is true. | |
93 | ||
94 | Returns the newly created basic block. */ | |
95 | ||
96 | static basic_block | |
97 | hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip, | |
98 | tree cond, edge e_true, | |
99 | bool update_dominators) | |
100 | { | |
101 | tree tmp; | |
102 | gimple cond_stmt; | |
103 | edge e_false; | |
104 | basic_block new_bb, split_bb = gsi_bb (*gsip); | |
105 | bool dominated_e_true = false; | |
106 | ||
107 | gcc_assert (e_true->src == split_bb); | |
108 | ||
109 | if (update_dominators | |
110 | && get_immediate_dominator (CDI_DOMINATORS, e_true->dest) == split_bb) | |
111 | dominated_e_true = true; | |
112 | ||
113 | tmp = force_gimple_operand_gsi (gsip, cond, /*simple=*/true, NULL, | |
114 | /*before=*/true, GSI_SAME_STMT); | |
115 | cond_stmt = gimple_build_cond_from_tree (tmp, NULL_TREE, NULL_TREE); | |
116 | gsi_insert_before (gsip, cond_stmt, GSI_SAME_STMT); | |
117 | ||
118 | e_false = split_block (split_bb, cond_stmt); | |
119 | new_bb = e_false->dest; | |
120 | redirect_edge_pred (e_true, split_bb); | |
121 | ||
122 | e_true->flags &= ~EDGE_FALLTHRU; | |
123 | e_true->flags |= EDGE_TRUE_VALUE; | |
124 | ||
125 | e_false->flags &= ~EDGE_FALLTHRU; | |
126 | e_false->flags |= EDGE_FALSE_VALUE; | |
127 | e_false->probability = REG_BR_PROB_BASE - e_true->probability; | |
128 | e_false->count = split_bb->count - e_true->count; | |
129 | new_bb->count = e_false->count; | |
130 | ||
131 | if (update_dominators) | |
132 | { | |
133 | if (dominated_e_true) | |
134 | set_immediate_dominator (CDI_DOMINATORS, e_true->dest, split_bb); | |
135 | set_immediate_dominator (CDI_DOMINATORS, e_false->dest, split_bb); | |
136 | } | |
137 | ||
138 | return new_bb; | |
139 | } | |
140 | ||
141 | ||
531b10fc SB |
142 | /* Return true if a switch should be expanded as a bit test. |
143 | RANGE is the difference between highest and lowest case. | |
144 | UNIQ is number of unique case node targets, not counting the default case. | |
145 | COUNT is the number of comparisons needed, not counting the default case. */ | |
146 | ||
147 | static bool | |
148 | expand_switch_using_bit_tests_p (tree range, | |
149 | unsigned int uniq, | |
72798784 | 150 | unsigned int count, bool speed_p) |
531b10fc SB |
151 | { |
152 | return (((uniq == 1 && count >= 3) | |
153 | || (uniq == 2 && count >= 5) | |
154 | || (uniq == 3 && count >= 6)) | |
72798784 | 155 | && lshift_cheap_p (speed_p) |
531b10fc SB |
156 | && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0 |
157 | && compare_tree_int (range, 0) > 0); | |
158 | } | |
159 | \f | |
160 | /* Implement switch statements with bit tests | |
161 | ||
162 | A GIMPLE switch statement can be expanded to a short sequence of bit-wise | |
163 | comparisons. "switch(x)" is converted into "if ((1 << (x-MINVAL)) & CST)" | |
164 | where CST and MINVAL are integer constants. This is better than a series | |
165 | of compare-and-banch insns in some cases, e.g. we can implement: | |
166 | ||
167 | if ((x==4) || (x==6) || (x==9) || (x==11)) | |
168 | ||
169 | as a single bit test: | |
170 | ||
171 | if ((1<<x) & ((1<<4)|(1<<6)|(1<<9)|(1<<11))) | |
172 | ||
173 | This transformation is only applied if the number of case targets is small, | |
34540577 | 174 | if CST constains at least 3 bits, and "1 << x" is cheap. The bit tests are |
531b10fc SB |
175 | performed in "word_mode". |
176 | ||
177 | The following example shows the code the transformation generates: | |
178 | ||
179 | int bar(int x) | |
180 | { | |
181 | switch (x) | |
182 | { | |
183 | case '0': case '1': case '2': case '3': case '4': | |
184 | case '5': case '6': case '7': case '8': case '9': | |
185 | case 'A': case 'B': case 'C': case 'D': case 'E': | |
186 | case 'F': | |
187 | return 1; | |
188 | } | |
189 | return 0; | |
190 | } | |
191 | ||
192 | ==> | |
193 | ||
194 | bar (int x) | |
195 | { | |
196 | tmp1 = x - 48; | |
197 | if (tmp1 > (70 - 48)) goto L2; | |
198 | tmp2 = 1 << tmp1; | |
199 | tmp3 = 0b11111100000001111111111; | |
200 | if ((tmp2 & tmp3) != 0) goto L1 ; else goto L2; | |
201 | L1: | |
202 | return 1; | |
203 | L2: | |
204 | return 0; | |
205 | } | |
206 | ||
207 | TODO: There are still some improvements to this transformation that could | |
208 | be implemented: | |
209 | ||
210 | * A narrower mode than word_mode could be used if that is cheaper, e.g. | |
211 | for x86_64 where a narrower-mode shift may result in smaller code. | |
212 | ||
213 | * The compounded constant could be shifted rather than the one. The | |
214 | test would be either on the sign bit or on the least significant bit, | |
215 | depending on the direction of the shift. On some machines, the test | |
216 | for the branch would be free if the bit to test is already set by the | |
217 | shift operation. | |
218 | ||
219 | This transformation was contributed by Roger Sayle, see this e-mail: | |
220 | http://gcc.gnu.org/ml/gcc-patches/2003-01/msg01950.html | |
221 | */ | |
222 | ||
223 | /* A case_bit_test represents a set of case nodes that may be | |
224 | selected from using a bit-wise comparison. HI and LO hold | |
225 | the integer to be tested against, TARGET_EDGE contains the | |
226 | edge to the basic block to jump to upon success and BITS | |
227 | counts the number of case nodes handled by this test, | |
228 | typically the number of bits set in HI:LO. The LABEL field | |
229 | is used to quickly identify all cases in this set without | |
230 | looking at label_to_block for every case label. */ | |
231 | ||
232 | struct case_bit_test | |
233 | { | |
aa79a1e1 | 234 | wide_int mask; |
531b10fc SB |
235 | edge target_edge; |
236 | tree label; | |
237 | int bits; | |
238 | }; | |
239 | ||
240 | /* Comparison function for qsort to order bit tests by decreasing | |
241 | probability of execution. Our best guess comes from a measured | |
242 | profile. If the profile counts are equal, break even on the | |
243 | number of case nodes, i.e. the node with the most cases gets | |
244 | tested first. | |
245 | ||
246 | TODO: Actually this currently runs before a profile is available. | |
247 | Therefore the case-as-bit-tests transformation should be done | |
248 | later in the pass pipeline, or something along the lines of | |
249 | "Efficient and effective branch reordering using profile data" | |
250 | (Yang et. al., 2002) should be implemented (although, how good | |
251 | is a paper is called "Efficient and effective ..." when the | |
252 | latter is implied by the former, but oh well...). */ | |
253 | ||
254 | static int | |
255 | case_bit_test_cmp (const void *p1, const void *p2) | |
256 | { | |
257 | const struct case_bit_test *const d1 = (const struct case_bit_test *) p1; | |
258 | const struct case_bit_test *const d2 = (const struct case_bit_test *) p2; | |
259 | ||
260 | if (d2->target_edge->count != d1->target_edge->count) | |
261 | return d2->target_edge->count - d1->target_edge->count; | |
262 | if (d2->bits != d1->bits) | |
263 | return d2->bits - d1->bits; | |
264 | ||
265 | /* Stabilize the sort. */ | |
266 | return LABEL_DECL_UID (d2->label) - LABEL_DECL_UID (d1->label); | |
267 | } | |
268 | ||
269 | /* Expand a switch statement by a short sequence of bit-wise | |
270 | comparisons. "switch(x)" is effectively converted into | |
271 | "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are | |
272 | integer constants. | |
273 | ||
274 | INDEX_EXPR is the value being switched on. | |
275 | ||
276 | MINVAL is the lowest case value of in the case nodes, | |
277 | and RANGE is highest value minus MINVAL. MINVAL and RANGE | |
278 | are not guaranteed to be of the same type as INDEX_EXPR | |
279 | (the gimplifier doesn't change the type of case label values, | |
280 | and MINVAL and RANGE are derived from those values). | |
aa79a1e1 | 281 | MAXVAL is MINVAL + RANGE. |
531b10fc SB |
282 | |
283 | There *MUST* be MAX_CASE_BIT_TESTS or less unique case | |
284 | node targets. */ | |
285 | ||
286 | static void | |
287 | emit_case_bit_tests (gimple swtch, tree index_expr, | |
aa79a1e1 | 288 | tree minval, tree range, tree maxval) |
531b10fc SB |
289 | { |
290 | struct case_bit_test test[MAX_CASE_BIT_TESTS]; | |
291 | unsigned int i, j, k; | |
292 | unsigned int count; | |
293 | ||
294 | basic_block switch_bb = gimple_bb (swtch); | |
295 | basic_block default_bb, new_default_bb, new_bb; | |
296 | edge default_edge; | |
297 | bool update_dom = dom_info_available_p (CDI_DOMINATORS); | |
298 | ||
6e1aa848 | 299 | vec<basic_block> bbs_to_fix_dom = vNULL; |
531b10fc SB |
300 | |
301 | tree index_type = TREE_TYPE (index_expr); | |
302 | tree unsigned_index_type = unsigned_type_for (index_type); | |
303 | unsigned int branch_num = gimple_switch_num_labels (swtch); | |
304 | ||
305 | gimple_stmt_iterator gsi; | |
306 | gimple shift_stmt; | |
307 | ||
308 | tree idx, tmp, csui; | |
309 | tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1); | |
310 | tree word_mode_zero = fold_convert (word_type_node, integer_zero_node); | |
311 | tree word_mode_one = fold_convert (word_type_node, integer_one_node); | |
aa79a1e1 JJ |
312 | int prec = TYPE_PRECISION (word_type_node); |
313 | wide_int wone = wi::one (prec); | |
531b10fc SB |
314 | |
315 | memset (&test, 0, sizeof (test)); | |
316 | ||
317 | /* Get the edge for the default case. */ | |
fd8d363e | 318 | tmp = gimple_switch_default_label (swtch); |
531b10fc SB |
319 | default_bb = label_to_block (CASE_LABEL (tmp)); |
320 | default_edge = find_edge (switch_bb, default_bb); | |
321 | ||
322 | /* Go through all case labels, and collect the case labels, profile | |
323 | counts, and other information we need to build the branch tests. */ | |
324 | count = 0; | |
325 | for (i = 1; i < branch_num; i++) | |
326 | { | |
327 | unsigned int lo, hi; | |
328 | tree cs = gimple_switch_label (swtch, i); | |
329 | tree label = CASE_LABEL (cs); | |
8166ff4d | 330 | edge e = find_edge (switch_bb, label_to_block (label)); |
531b10fc | 331 | for (k = 0; k < count; k++) |
8166ff4d | 332 | if (e == test[k].target_edge) |
531b10fc SB |
333 | break; |
334 | ||
335 | if (k == count) | |
336 | { | |
531b10fc | 337 | gcc_checking_assert (count < MAX_CASE_BIT_TESTS); |
aa79a1e1 | 338 | test[k].mask = wi::zero (prec); |
531b10fc SB |
339 | test[k].target_edge = e; |
340 | test[k].label = label; | |
341 | test[k].bits = 1; | |
342 | count++; | |
343 | } | |
344 | else | |
345 | test[k].bits++; | |
346 | ||
386b1f1f RS |
347 | lo = tree_to_uhwi (int_const_binop (MINUS_EXPR, |
348 | CASE_LOW (cs), minval)); | |
531b10fc SB |
349 | if (CASE_HIGH (cs) == NULL_TREE) |
350 | hi = lo; | |
351 | else | |
386b1f1f RS |
352 | hi = tree_to_uhwi (int_const_binop (MINUS_EXPR, |
353 | CASE_HIGH (cs), minval)); | |
531b10fc SB |
354 | |
355 | for (j = lo; j <= hi; j++) | |
aa79a1e1 | 356 | test[k].mask |= wi::lshift (wone, j); |
531b10fc SB |
357 | } |
358 | ||
c3284718 | 359 | qsort (test, count, sizeof (*test), case_bit_test_cmp); |
531b10fc | 360 | |
aa79a1e1 JJ |
361 | /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of |
362 | the minval subtractions, but it might make the mask constants more | |
363 | expensive. So, compare the costs. */ | |
364 | if (compare_tree_int (minval, 0) > 0 | |
365 | && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0) | |
366 | { | |
367 | int cost_diff; | |
368 | HOST_WIDE_INT m = tree_to_uhwi (minval); | |
369 | rtx reg = gen_raw_REG (word_mode, 10000); | |
370 | bool speed_p = optimize_bb_for_speed_p (gimple_bb (swtch)); | |
371 | cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg, | |
372 | GEN_INT (-m)), speed_p); | |
373 | for (i = 0; i < count; i++) | |
374 | { | |
375 | rtx r = immed_wide_int_const (test[i].mask, word_mode); | |
376 | cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r), speed_p); | |
377 | r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode); | |
378 | cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r), speed_p); | |
379 | } | |
380 | if (cost_diff > 0) | |
381 | { | |
382 | for (i = 0; i < count; i++) | |
383 | test[i].mask = wi::lshift (test[i].mask, m); | |
384 | minval = build_zero_cst (TREE_TYPE (minval)); | |
385 | range = maxval; | |
386 | } | |
387 | } | |
388 | ||
531b10fc SB |
389 | /* We generate two jumps to the default case label. |
390 | Split the default edge, so that we don't have to do any PHI node | |
391 | updating. */ | |
392 | new_default_bb = split_edge (default_edge); | |
393 | ||
394 | if (update_dom) | |
395 | { | |
9771b263 DN |
396 | bbs_to_fix_dom.create (10); |
397 | bbs_to_fix_dom.quick_push (switch_bb); | |
398 | bbs_to_fix_dom.quick_push (default_bb); | |
399 | bbs_to_fix_dom.quick_push (new_default_bb); | |
531b10fc SB |
400 | } |
401 | ||
402 | /* Now build the test-and-branch code. */ | |
403 | ||
404 | gsi = gsi_last_bb (switch_bb); | |
405 | ||
d9e408de TV |
406 | /* idx = (unsigned)x - minval. */ |
407 | idx = fold_convert (unsigned_index_type, index_expr); | |
408 | idx = fold_build2 (MINUS_EXPR, unsigned_index_type, idx, | |
409 | fold_convert (unsigned_index_type, minval)); | |
531b10fc SB |
410 | idx = force_gimple_operand_gsi (&gsi, idx, |
411 | /*simple=*/true, NULL_TREE, | |
412 | /*before=*/true, GSI_SAME_STMT); | |
413 | ||
414 | /* if (idx > range) goto default */ | |
415 | range = force_gimple_operand_gsi (&gsi, | |
416 | fold_convert (unsigned_index_type, range), | |
417 | /*simple=*/true, NULL_TREE, | |
418 | /*before=*/true, GSI_SAME_STMT); | |
419 | tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range); | |
420 | new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, default_edge, update_dom); | |
421 | if (update_dom) | |
9771b263 | 422 | bbs_to_fix_dom.quick_push (new_bb); |
531b10fc SB |
423 | gcc_assert (gimple_bb (swtch) == new_bb); |
424 | gsi = gsi_last_bb (new_bb); | |
425 | ||
426 | /* Any blocks dominated by the GIMPLE_SWITCH, but that are not successors | |
427 | of NEW_BB, are still immediately dominated by SWITCH_BB. Make it so. */ | |
428 | if (update_dom) | |
429 | { | |
9771b263 | 430 | vec<basic_block> dom_bbs; |
531b10fc SB |
431 | basic_block dom_son; |
432 | ||
433 | dom_bbs = get_dominated_by (CDI_DOMINATORS, new_bb); | |
9771b263 | 434 | FOR_EACH_VEC_ELT (dom_bbs, i, dom_son) |
531b10fc SB |
435 | { |
436 | edge e = find_edge (new_bb, dom_son); | |
437 | if (e && single_pred_p (e->dest)) | |
438 | continue; | |
439 | set_immediate_dominator (CDI_DOMINATORS, dom_son, switch_bb); | |
9771b263 | 440 | bbs_to_fix_dom.safe_push (dom_son); |
531b10fc | 441 | } |
9771b263 | 442 | dom_bbs.release (); |
531b10fc SB |
443 | } |
444 | ||
445 | /* csui = (1 << (word_mode) idx) */ | |
83d5977e | 446 | csui = make_ssa_name (word_type_node, NULL); |
531b10fc SB |
447 | tmp = fold_build2 (LSHIFT_EXPR, word_type_node, word_mode_one, |
448 | fold_convert (word_type_node, idx)); | |
449 | tmp = force_gimple_operand_gsi (&gsi, tmp, | |
450 | /*simple=*/false, NULL_TREE, | |
451 | /*before=*/true, GSI_SAME_STMT); | |
452 | shift_stmt = gimple_build_assign (csui, tmp); | |
531b10fc SB |
453 | gsi_insert_before (&gsi, shift_stmt, GSI_SAME_STMT); |
454 | update_stmt (shift_stmt); | |
455 | ||
456 | /* for each unique set of cases: | |
457 | if (const & csui) goto target */ | |
458 | for (k = 0; k < count; k++) | |
459 | { | |
aa79a1e1 | 460 | tmp = wide_int_to_tree (word_type_node, test[k].mask); |
531b10fc SB |
461 | tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp); |
462 | tmp = force_gimple_operand_gsi (&gsi, tmp, | |
463 | /*simple=*/true, NULL_TREE, | |
464 | /*before=*/true, GSI_SAME_STMT); | |
465 | tmp = fold_build2 (NE_EXPR, boolean_type_node, tmp, word_mode_zero); | |
466 | new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, test[k].target_edge, | |
467 | update_dom); | |
468 | if (update_dom) | |
9771b263 | 469 | bbs_to_fix_dom.safe_push (new_bb); |
531b10fc SB |
470 | gcc_assert (gimple_bb (swtch) == new_bb); |
471 | gsi = gsi_last_bb (new_bb); | |
472 | } | |
473 | ||
474 | /* We should have removed all edges now. */ | |
475 | gcc_assert (EDGE_COUNT (gsi_bb (gsi)->succs) == 0); | |
476 | ||
477 | /* If nothing matched, go to the default label. */ | |
478 | make_edge (gsi_bb (gsi), new_default_bb, EDGE_FALLTHRU); | |
479 | ||
480 | /* The GIMPLE_SWITCH is now redundant. */ | |
481 | gsi_remove (&gsi, true); | |
482 | ||
483 | if (update_dom) | |
484 | { | |
485 | /* Fix up the dominator tree. */ | |
486 | iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
9771b263 | 487 | bbs_to_fix_dom.release (); |
531b10fc SB |
488 | } |
489 | } | |
490 | \f | |
b6e99746 MJ |
491 | /* |
492 | Switch initialization conversion | |
493 | ||
494 | The following pass changes simple initializations of scalars in a switch | |
fade902a SB |
495 | statement into initializations from a static array. Obviously, the values |
496 | must be constant and known at compile time and a default branch must be | |
b6e99746 MJ |
497 | provided. For example, the following code: |
498 | ||
499 | int a,b; | |
500 | ||
501 | switch (argc) | |
502 | { | |
503 | case 1: | |
504 | case 2: | |
505 | a_1 = 8; | |
506 | b_1 = 6; | |
507 | break; | |
508 | case 3: | |
509 | a_2 = 9; | |
510 | b_2 = 5; | |
511 | break; | |
512 | case 12: | |
513 | a_3 = 10; | |
514 | b_3 = 4; | |
515 | break; | |
516 | default: | |
517 | a_4 = 16; | |
518 | b_4 = 1; | |
886cd84f | 519 | break; |
b6e99746 MJ |
520 | } |
521 | a_5 = PHI <a_1, a_2, a_3, a_4> | |
522 | b_5 = PHI <b_1, b_2, b_3, b_4> | |
523 | ||
524 | ||
525 | is changed into: | |
526 | ||
527 | static const int = CSWTCH01[] = {6, 6, 5, 1, 1, 1, 1, 1, 1, 1, 1, 4}; | |
528 | static const int = CSWTCH02[] = {8, 8, 9, 16, 16, 16, 16, 16, 16, 16, | |
529 | 16, 16, 10}; | |
530 | ||
531 | if (((unsigned) argc) - 1 < 11) | |
532 | { | |
533 | a_6 = CSWTCH02[argc - 1]; | |
534 | b_6 = CSWTCH01[argc - 1]; | |
535 | } | |
536 | else | |
537 | { | |
538 | a_7 = 16; | |
539 | b_7 = 1; | |
540 | } | |
886cd84f SB |
541 | a_5 = PHI <a_6, a_7> |
542 | b_b = PHI <b_6, b_7> | |
b6e99746 MJ |
543 | |
544 | There are further constraints. Specifically, the range of values across all | |
545 | case labels must not be bigger than SWITCH_CONVERSION_BRANCH_RATIO (default | |
531b10fc | 546 | eight) times the number of the actual switch branches. |
b6e99746 | 547 | |
531b10fc SB |
548 | This transformation was contributed by Martin Jambor, see this e-mail: |
549 | http://gcc.gnu.org/ml/gcc-patches/2008-07/msg00011.html */ | |
b6e99746 MJ |
550 | |
551 | /* The main structure of the pass. */ | |
552 | struct switch_conv_info | |
553 | { | |
886cd84f | 554 | /* The expression used to decide the switch branch. */ |
b6e99746 MJ |
555 | tree index_expr; |
556 | ||
886cd84f SB |
557 | /* The following integer constants store the minimum and maximum value |
558 | covered by the case labels. */ | |
b6e99746 | 559 | tree range_min; |
886cd84f | 560 | tree range_max; |
b6e99746 | 561 | |
886cd84f SB |
562 | /* The difference between the above two numbers. Stored here because it |
563 | is used in all the conversion heuristics, as well as for some of the | |
564 | transformation, and it is expensive to re-compute it all the time. */ | |
b6e99746 MJ |
565 | tree range_size; |
566 | ||
886cd84f | 567 | /* Basic block that contains the actual GIMPLE_SWITCH. */ |
b6e99746 MJ |
568 | basic_block switch_bb; |
569 | ||
886cd84f SB |
570 | /* Basic block that is the target of the default case. */ |
571 | basic_block default_bb; | |
572 | ||
573 | /* The single successor block of all branches out of the GIMPLE_SWITCH, | |
574 | if such a block exists. Otherwise NULL. */ | |
b6e99746 MJ |
575 | basic_block final_bb; |
576 | ||
886cd84f SB |
577 | /* The probability of the default edge in the replaced switch. */ |
578 | int default_prob; | |
579 | ||
580 | /* The count of the default edge in the replaced switch. */ | |
581 | gcov_type default_count; | |
582 | ||
583 | /* Combined count of all other (non-default) edges in the replaced switch. */ | |
584 | gcov_type other_count; | |
585 | ||
b6e99746 MJ |
586 | /* Number of phi nodes in the final bb (that we'll be replacing). */ |
587 | int phi_count; | |
588 | ||
b1ae1681 | 589 | /* Array of default values, in the same order as phi nodes. */ |
b6e99746 MJ |
590 | tree *default_values; |
591 | ||
592 | /* Constructors of new static arrays. */ | |
9771b263 | 593 | vec<constructor_elt, va_gc> **constructors; |
b6e99746 MJ |
594 | |
595 | /* Array of ssa names that are initialized with a value from a new static | |
596 | array. */ | |
597 | tree *target_inbound_names; | |
598 | ||
599 | /* Array of ssa names that are initialized with the default value if the | |
600 | switch expression is out of range. */ | |
601 | tree *target_outbound_names; | |
602 | ||
b1ae1681 MJ |
603 | /* The first load statement that loads a temporary from a new static array. |
604 | */ | |
726a989a | 605 | gimple arr_ref_first; |
b6e99746 MJ |
606 | |
607 | /* The last load statement that loads a temporary from a new static array. */ | |
726a989a | 608 | gimple arr_ref_last; |
b6e99746 MJ |
609 | |
610 | /* String reason why the case wasn't a good candidate that is written to the | |
611 | dump file, if there is one. */ | |
612 | const char *reason; | |
8e97bc2b JJ |
613 | |
614 | /* Parameters for expand_switch_using_bit_tests. Should be computed | |
615 | the same way as in expand_case. */ | |
886cd84f SB |
616 | unsigned int uniq; |
617 | unsigned int count; | |
b6e99746 MJ |
618 | }; |
619 | ||
886cd84f | 620 | /* Collect information about GIMPLE_SWITCH statement SWTCH into INFO. */ |
b6e99746 | 621 | |
886cd84f SB |
622 | static void |
623 | collect_switch_conv_info (gimple swtch, struct switch_conv_info *info) | |
b6e99746 | 624 | { |
726a989a | 625 | unsigned int branch_num = gimple_switch_num_labels (swtch); |
886cd84f SB |
626 | tree min_case, max_case; |
627 | unsigned int count, i; | |
628 | edge e, e_default; | |
629 | edge_iterator ei; | |
630 | ||
631 | memset (info, 0, sizeof (*info)); | |
b6e99746 MJ |
632 | |
633 | /* The gimplifier has already sorted the cases by CASE_LOW and ensured there | |
fd8d363e SB |
634 | is a default label which is the first in the vector. |
635 | Collect the bits we can deduce from the CFG. */ | |
886cd84f SB |
636 | info->index_expr = gimple_switch_index (swtch); |
637 | info->switch_bb = gimple_bb (swtch); | |
638 | info->default_bb = | |
fd8d363e | 639 | label_to_block (CASE_LABEL (gimple_switch_default_label (swtch))); |
886cd84f SB |
640 | e_default = find_edge (info->switch_bb, info->default_bb); |
641 | info->default_prob = e_default->probability; | |
642 | info->default_count = e_default->count; | |
643 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
644 | if (e != e_default) | |
645 | info->other_count += e->count; | |
b6e99746 | 646 | |
886cd84f | 647 | /* See if there is one common successor block for all branch |
866f20d6 RB |
648 | targets. If it exists, record it in FINAL_BB. |
649 | Start with the destination of the default case as guess | |
650 | or its destination in case it is a forwarder block. */ | |
651 | if (! single_pred_p (e_default->dest)) | |
652 | info->final_bb = e_default->dest; | |
653 | else if (single_succ_p (e_default->dest) | |
654 | && ! single_pred_p (single_succ (e_default->dest))) | |
655 | info->final_bb = single_succ (e_default->dest); | |
656 | /* Require that all switch destinations are either that common | |
657 | FINAL_BB or a forwarder to it. */ | |
886cd84f SB |
658 | if (info->final_bb) |
659 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
660 | { | |
661 | if (e->dest == info->final_bb) | |
662 | continue; | |
663 | ||
664 | if (single_pred_p (e->dest) | |
665 | && single_succ_p (e->dest) | |
666 | && single_succ (e->dest) == info->final_bb) | |
667 | continue; | |
668 | ||
669 | info->final_bb = NULL; | |
670 | break; | |
671 | } | |
672 | ||
673 | /* Get upper and lower bounds of case values, and the covered range. */ | |
674 | min_case = gimple_switch_label (swtch, 1); | |
726a989a | 675 | max_case = gimple_switch_label (swtch, branch_num - 1); |
886cd84f SB |
676 | |
677 | info->range_min = CASE_LOW (min_case); | |
b6e99746 | 678 | if (CASE_HIGH (max_case) != NULL_TREE) |
886cd84f | 679 | info->range_max = CASE_HIGH (max_case); |
b6e99746 | 680 | else |
886cd84f SB |
681 | info->range_max = CASE_LOW (max_case); |
682 | ||
683 | info->range_size = | |
684 | int_const_binop (MINUS_EXPR, info->range_max, info->range_min); | |
b6e99746 | 685 | |
886cd84f SB |
686 | /* Get a count of the number of case labels. Single-valued case labels |
687 | simply count as one, but a case range counts double, since it may | |
688 | require two compares if it gets lowered as a branching tree. */ | |
689 | count = 0; | |
690 | for (i = 1; i < branch_num; i++) | |
691 | { | |
692 | tree elt = gimple_switch_label (swtch, i); | |
693 | count++; | |
694 | if (CASE_HIGH (elt) | |
695 | && ! tree_int_cst_equal (CASE_LOW (elt), CASE_HIGH (elt))) | |
696 | count++; | |
697 | } | |
698 | info->count = count; | |
699 | ||
700 | /* Get the number of unique non-default targets out of the GIMPLE_SWITCH | |
701 | block. Assume a CFG cleanup would have already removed degenerate | |
702 | switch statements, this allows us to just use EDGE_COUNT. */ | |
703 | info->uniq = EDGE_COUNT (gimple_bb (swtch)->succs) - 1; | |
704 | } | |
b6e99746 | 705 | |
886cd84f SB |
706 | /* Checks whether the range given by individual case statements of the SWTCH |
707 | switch statement isn't too big and whether the number of branches actually | |
708 | satisfies the size of the new array. */ | |
b6e99746 | 709 | |
886cd84f SB |
710 | static bool |
711 | check_range (struct switch_conv_info *info) | |
712 | { | |
fade902a | 713 | gcc_assert (info->range_size); |
cc269bb6 | 714 | if (!tree_fits_uhwi_p (info->range_size)) |
b6e99746 | 715 | { |
fade902a | 716 | info->reason = "index range way too large or otherwise unusable"; |
b6e99746 MJ |
717 | return false; |
718 | } | |
719 | ||
7d362f6c | 720 | if (tree_to_uhwi (info->range_size) |
886cd84f | 721 | > ((unsigned) info->count * SWITCH_CONVERSION_BRANCH_RATIO)) |
b6e99746 | 722 | { |
fade902a | 723 | info->reason = "the maximum range-branch ratio exceeded"; |
b6e99746 MJ |
724 | return false; |
725 | } | |
726 | ||
727 | return true; | |
728 | } | |
729 | ||
886cd84f | 730 | /* Checks whether all but the FINAL_BB basic blocks are empty. */ |
b6e99746 MJ |
731 | |
732 | static bool | |
886cd84f | 733 | check_all_empty_except_final (struct switch_conv_info *info) |
b6e99746 | 734 | { |
b6e99746 | 735 | edge e; |
886cd84f | 736 | edge_iterator ei; |
b6e99746 | 737 | |
886cd84f | 738 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) |
b6e99746 | 739 | { |
886cd84f SB |
740 | if (e->dest == info->final_bb) |
741 | continue; | |
b6e99746 | 742 | |
886cd84f | 743 | if (!empty_block_p (e->dest)) |
b6e99746 | 744 | { |
fade902a | 745 | info->reason = "bad case - a non-final BB not empty"; |
b6e99746 MJ |
746 | return false; |
747 | } | |
b6e99746 MJ |
748 | } |
749 | ||
750 | return true; | |
751 | } | |
752 | ||
753 | /* This function checks whether all required values in phi nodes in final_bb | |
754 | are constants. Required values are those that correspond to a basic block | |
755 | which is a part of the examined switch statement. It returns true if the | |
756 | phi nodes are OK, otherwise false. */ | |
757 | ||
758 | static bool | |
fade902a | 759 | check_final_bb (struct switch_conv_info *info) |
b6e99746 | 760 | { |
726a989a | 761 | gimple_stmt_iterator gsi; |
b6e99746 | 762 | |
fade902a SB |
763 | info->phi_count = 0; |
764 | for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
b6e99746 | 765 | { |
726a989a RB |
766 | gimple phi = gsi_stmt (gsi); |
767 | unsigned int i; | |
b6e99746 | 768 | |
fade902a | 769 | info->phi_count++; |
b6e99746 | 770 | |
726a989a | 771 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
b6e99746 | 772 | { |
726a989a | 773 | basic_block bb = gimple_phi_arg_edge (phi, i)->src; |
b6e99746 | 774 | |
fade902a SB |
775 | if (bb == info->switch_bb |
776 | || (single_pred_p (bb) && single_pred (bb) == info->switch_bb)) | |
b6e99746 | 777 | { |
f6e6e990 JJ |
778 | tree reloc, val; |
779 | ||
780 | val = gimple_phi_arg_def (phi, i); | |
781 | if (!is_gimple_ip_invariant (val)) | |
782 | { | |
fade902a | 783 | info->reason = "non-invariant value from a case"; |
f6e6e990 JJ |
784 | return false; /* Non-invariant argument. */ |
785 | } | |
786 | reloc = initializer_constant_valid_p (val, TREE_TYPE (val)); | |
787 | if ((flag_pic && reloc != null_pointer_node) | |
788 | || (!flag_pic && reloc == NULL_TREE)) | |
789 | { | |
790 | if (reloc) | |
fade902a SB |
791 | info->reason |
792 | = "value from a case would need runtime relocations"; | |
f6e6e990 | 793 | else |
fade902a SB |
794 | info->reason |
795 | = "value from a case is not a valid initializer"; | |
f6e6e990 JJ |
796 | return false; |
797 | } | |
b6e99746 MJ |
798 | } |
799 | } | |
800 | } | |
801 | ||
802 | return true; | |
803 | } | |
804 | ||
805 | /* The following function allocates default_values, target_{in,out}_names and | |
806 | constructors arrays. The last one is also populated with pointers to | |
807 | vectors that will become constructors of new arrays. */ | |
808 | ||
809 | static void | |
fade902a | 810 | create_temp_arrays (struct switch_conv_info *info) |
b6e99746 MJ |
811 | { |
812 | int i; | |
813 | ||
fade902a | 814 | info->default_values = XCNEWVEC (tree, info->phi_count * 3); |
9771b263 DN |
815 | /* ??? Macros do not support multi argument templates in their |
816 | argument list. We create a typedef to work around that problem. */ | |
817 | typedef vec<constructor_elt, va_gc> *vec_constructor_elt_gc; | |
818 | info->constructors = XCNEWVEC (vec_constructor_elt_gc, info->phi_count); | |
fade902a SB |
819 | info->target_inbound_names = info->default_values + info->phi_count; |
820 | info->target_outbound_names = info->target_inbound_names + info->phi_count; | |
821 | for (i = 0; i < info->phi_count; i++) | |
ae7e9ddd | 822 | vec_alloc (info->constructors[i], tree_to_uhwi (info->range_size) + 1); |
b6e99746 MJ |
823 | } |
824 | ||
825 | /* Free the arrays created by create_temp_arrays(). The vectors that are | |
826 | created by that function are not freed here, however, because they have | |
827 | already become constructors and must be preserved. */ | |
828 | ||
829 | static void | |
fade902a | 830 | free_temp_arrays (struct switch_conv_info *info) |
b6e99746 | 831 | { |
fade902a SB |
832 | XDELETEVEC (info->constructors); |
833 | XDELETEVEC (info->default_values); | |
b6e99746 MJ |
834 | } |
835 | ||
836 | /* Populate the array of default values in the order of phi nodes. | |
837 | DEFAULT_CASE is the CASE_LABEL_EXPR for the default switch branch. */ | |
838 | ||
839 | static void | |
fade902a | 840 | gather_default_values (tree default_case, struct switch_conv_info *info) |
b6e99746 | 841 | { |
726a989a | 842 | gimple_stmt_iterator gsi; |
b6e99746 MJ |
843 | basic_block bb = label_to_block (CASE_LABEL (default_case)); |
844 | edge e; | |
726a989a | 845 | int i = 0; |
b6e99746 MJ |
846 | |
847 | gcc_assert (CASE_LOW (default_case) == NULL_TREE); | |
848 | ||
fade902a SB |
849 | if (bb == info->final_bb) |
850 | e = find_edge (info->switch_bb, bb); | |
b6e99746 MJ |
851 | else |
852 | e = single_succ_edge (bb); | |
853 | ||
fade902a | 854 | for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
b6e99746 | 855 | { |
726a989a | 856 | gimple phi = gsi_stmt (gsi); |
b6e99746 MJ |
857 | tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
858 | gcc_assert (val); | |
fade902a | 859 | info->default_values[i++] = val; |
b6e99746 MJ |
860 | } |
861 | } | |
862 | ||
863 | /* The following function populates the vectors in the constructors array with | |
864 | future contents of the static arrays. The vectors are populated in the | |
865 | order of phi nodes. SWTCH is the switch statement being converted. */ | |
866 | ||
867 | static void | |
fade902a | 868 | build_constructors (gimple swtch, struct switch_conv_info *info) |
b6e99746 | 869 | { |
726a989a | 870 | unsigned i, branch_num = gimple_switch_num_labels (swtch); |
fade902a | 871 | tree pos = info->range_min; |
b6e99746 | 872 | |
726a989a | 873 | for (i = 1; i < branch_num; i++) |
b6e99746 | 874 | { |
726a989a | 875 | tree cs = gimple_switch_label (swtch, i); |
b6e99746 MJ |
876 | basic_block bb = label_to_block (CASE_LABEL (cs)); |
877 | edge e; | |
726a989a RB |
878 | tree high; |
879 | gimple_stmt_iterator gsi; | |
b6e99746 MJ |
880 | int j; |
881 | ||
fade902a SB |
882 | if (bb == info->final_bb) |
883 | e = find_edge (info->switch_bb, bb); | |
b6e99746 MJ |
884 | else |
885 | e = single_succ_edge (bb); | |
886 | gcc_assert (e); | |
887 | ||
888 | while (tree_int_cst_lt (pos, CASE_LOW (cs))) | |
889 | { | |
890 | int k; | |
fade902a | 891 | for (k = 0; k < info->phi_count; k++) |
b6e99746 | 892 | { |
f32682ca | 893 | constructor_elt elt; |
b6e99746 | 894 | |
f32682ca | 895 | elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); |
d1f98542 RB |
896 | elt.value |
897 | = unshare_expr_without_location (info->default_values[k]); | |
9771b263 | 898 | info->constructors[k]->quick_push (elt); |
b6e99746 MJ |
899 | } |
900 | ||
807e902e KZ |
901 | pos = int_const_binop (PLUS_EXPR, pos, |
902 | build_int_cst (TREE_TYPE (pos), 1)); | |
b6e99746 | 903 | } |
b1ae1681 | 904 | gcc_assert (tree_int_cst_equal (pos, CASE_LOW (cs))); |
b6e99746 MJ |
905 | |
906 | j = 0; | |
907 | if (CASE_HIGH (cs)) | |
908 | high = CASE_HIGH (cs); | |
909 | else | |
b1ae1681 | 910 | high = CASE_LOW (cs); |
fade902a | 911 | for (gsi = gsi_start_phis (info->final_bb); |
726a989a | 912 | !gsi_end_p (gsi); gsi_next (&gsi)) |
b6e99746 | 913 | { |
726a989a | 914 | gimple phi = gsi_stmt (gsi); |
b6e99746 | 915 | tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
7f2a9982 | 916 | tree low = CASE_LOW (cs); |
b6e99746 MJ |
917 | pos = CASE_LOW (cs); |
918 | ||
b8698a0f | 919 | do |
b6e99746 | 920 | { |
f32682ca | 921 | constructor_elt elt; |
b6e99746 | 922 | |
f32682ca | 923 | elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); |
d1f98542 | 924 | elt.value = unshare_expr_without_location (val); |
9771b263 | 925 | info->constructors[j]->quick_push (elt); |
b6e99746 | 926 | |
807e902e KZ |
927 | pos = int_const_binop (PLUS_EXPR, pos, |
928 | build_int_cst (TREE_TYPE (pos), 1)); | |
7156c8ab MJ |
929 | } while (!tree_int_cst_lt (high, pos) |
930 | && tree_int_cst_lt (low, pos)); | |
b6e99746 MJ |
931 | j++; |
932 | } | |
933 | } | |
934 | } | |
935 | ||
7156c8ab MJ |
936 | /* If all values in the constructor vector are the same, return the value. |
937 | Otherwise return NULL_TREE. Not supposed to be called for empty | |
938 | vectors. */ | |
939 | ||
940 | static tree | |
9771b263 | 941 | constructor_contains_same_values_p (vec<constructor_elt, va_gc> *vec) |
7156c8ab | 942 | { |
8e97bc2b | 943 | unsigned int i; |
7156c8ab | 944 | tree prev = NULL_TREE; |
8e97bc2b | 945 | constructor_elt *elt; |
7156c8ab | 946 | |
9771b263 | 947 | FOR_EACH_VEC_SAFE_ELT (vec, i, elt) |
7156c8ab | 948 | { |
7156c8ab MJ |
949 | if (!prev) |
950 | prev = elt->value; | |
951 | else if (!operand_equal_p (elt->value, prev, OEP_ONLY_CONST)) | |
952 | return NULL_TREE; | |
953 | } | |
954 | return prev; | |
955 | } | |
956 | ||
8e97bc2b JJ |
957 | /* Return type which should be used for array elements, either TYPE, |
958 | or for integral type some smaller integral type that can still hold | |
959 | all the constants. */ | |
960 | ||
961 | static tree | |
fade902a SB |
962 | array_value_type (gimple swtch, tree type, int num, |
963 | struct switch_conv_info *info) | |
8e97bc2b | 964 | { |
9771b263 | 965 | unsigned int i, len = vec_safe_length (info->constructors[num]); |
8e97bc2b | 966 | constructor_elt *elt; |
ef4bddc2 | 967 | machine_mode mode; |
8e97bc2b JJ |
968 | int sign = 0; |
969 | tree smaller_type; | |
970 | ||
971 | if (!INTEGRAL_TYPE_P (type)) | |
972 | return type; | |
973 | ||
974 | mode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (TYPE_MODE (type))); | |
975 | if (GET_MODE_SIZE (TYPE_MODE (type)) <= GET_MODE_SIZE (mode)) | |
976 | return type; | |
977 | ||
978 | if (len < (optimize_bb_for_size_p (gimple_bb (swtch)) ? 2 : 32)) | |
979 | return type; | |
980 | ||
9771b263 | 981 | FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
8e97bc2b | 982 | { |
807e902e | 983 | wide_int cst; |
8e97bc2b JJ |
984 | |
985 | if (TREE_CODE (elt->value) != INTEGER_CST) | |
986 | return type; | |
987 | ||
807e902e | 988 | cst = elt->value; |
8e97bc2b JJ |
989 | while (1) |
990 | { | |
991 | unsigned int prec = GET_MODE_BITSIZE (mode); | |
992 | if (prec > HOST_BITS_PER_WIDE_INT) | |
993 | return type; | |
994 | ||
807e902e | 995 | if (sign >= 0 && cst == wi::zext (cst, prec)) |
8e97bc2b | 996 | { |
807e902e | 997 | if (sign == 0 && cst == wi::sext (cst, prec)) |
8e97bc2b JJ |
998 | break; |
999 | sign = 1; | |
1000 | break; | |
1001 | } | |
807e902e | 1002 | if (sign <= 0 && cst == wi::sext (cst, prec)) |
8e97bc2b JJ |
1003 | { |
1004 | sign = -1; | |
1005 | break; | |
1006 | } | |
1007 | ||
1008 | if (sign == 1) | |
1009 | sign = 0; | |
1010 | ||
1011 | mode = GET_MODE_WIDER_MODE (mode); | |
1012 | if (mode == VOIDmode | |
1013 | || GET_MODE_SIZE (mode) >= GET_MODE_SIZE (TYPE_MODE (type))) | |
1014 | return type; | |
1015 | } | |
1016 | } | |
1017 | ||
1018 | if (sign == 0) | |
1019 | sign = TYPE_UNSIGNED (type) ? 1 : -1; | |
1020 | smaller_type = lang_hooks.types.type_for_mode (mode, sign >= 0); | |
1021 | if (GET_MODE_SIZE (TYPE_MODE (type)) | |
1022 | <= GET_MODE_SIZE (TYPE_MODE (smaller_type))) | |
1023 | return type; | |
1024 | ||
1025 | return smaller_type; | |
1026 | } | |
1027 | ||
b6e99746 MJ |
1028 | /* Create an appropriate array type and declaration and assemble a static array |
1029 | variable. Also create a load statement that initializes the variable in | |
1030 | question with a value from the static array. SWTCH is the switch statement | |
1031 | being converted, NUM is the index to arrays of constructors, default values | |
1032 | and target SSA names for this particular array. ARR_INDEX_TYPE is the type | |
1033 | of the index of the new array, PHI is the phi node of the final BB that | |
1034 | corresponds to the value that will be loaded from the created array. TIDX | |
7156c8ab MJ |
1035 | is an ssa name of a temporary variable holding the index for loads from the |
1036 | new array. */ | |
b6e99746 MJ |
1037 | |
1038 | static void | |
726a989a | 1039 | build_one_array (gimple swtch, int num, tree arr_index_type, gimple phi, |
fade902a | 1040 | tree tidx, struct switch_conv_info *info) |
b6e99746 | 1041 | { |
7156c8ab | 1042 | tree name, cst; |
726a989a | 1043 | gimple load; |
7156c8ab | 1044 | gimple_stmt_iterator gsi = gsi_for_stmt (swtch); |
c2255bc4 | 1045 | location_t loc = gimple_location (swtch); |
b6e99746 | 1046 | |
fade902a | 1047 | gcc_assert (info->default_values[num]); |
b6e99746 | 1048 | |
070ecdfd | 1049 | name = copy_ssa_name (PHI_RESULT (phi), NULL); |
fade902a | 1050 | info->target_inbound_names[num] = name; |
b6e99746 | 1051 | |
fade902a | 1052 | cst = constructor_contains_same_values_p (info->constructors[num]); |
7156c8ab MJ |
1053 | if (cst) |
1054 | load = gimple_build_assign (name, cst); | |
1055 | else | |
1056 | { | |
8e97bc2b | 1057 | tree array_type, ctor, decl, value_type, fetch, default_type; |
7156c8ab | 1058 | |
fade902a SB |
1059 | default_type = TREE_TYPE (info->default_values[num]); |
1060 | value_type = array_value_type (swtch, default_type, num, info); | |
7156c8ab | 1061 | array_type = build_array_type (value_type, arr_index_type); |
8e97bc2b JJ |
1062 | if (default_type != value_type) |
1063 | { | |
1064 | unsigned int i; | |
1065 | constructor_elt *elt; | |
1066 | ||
9771b263 | 1067 | FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
8e97bc2b JJ |
1068 | elt->value = fold_convert (value_type, elt->value); |
1069 | } | |
fade902a | 1070 | ctor = build_constructor (array_type, info->constructors[num]); |
7156c8ab | 1071 | TREE_CONSTANT (ctor) = true; |
5f7ae6b6 | 1072 | TREE_STATIC (ctor) = true; |
7156c8ab | 1073 | |
c2255bc4 | 1074 | decl = build_decl (loc, VAR_DECL, NULL_TREE, array_type); |
7156c8ab MJ |
1075 | TREE_STATIC (decl) = 1; |
1076 | DECL_INITIAL (decl) = ctor; | |
1077 | ||
1078 | DECL_NAME (decl) = create_tmp_var_name ("CSWTCH"); | |
1079 | DECL_ARTIFICIAL (decl) = 1; | |
1080 | TREE_CONSTANT (decl) = 1; | |
2e3b4885 | 1081 | TREE_READONLY (decl) = 1; |
9041d2e6 | 1082 | varpool_node::finalize_decl (decl); |
7156c8ab MJ |
1083 | |
1084 | fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE, | |
1085 | NULL_TREE); | |
8e97bc2b JJ |
1086 | if (default_type != value_type) |
1087 | { | |
1088 | fetch = fold_convert (default_type, fetch); | |
1089 | fetch = force_gimple_operand_gsi (&gsi, fetch, true, NULL_TREE, | |
1090 | true, GSI_SAME_STMT); | |
1091 | } | |
7156c8ab MJ |
1092 | load = gimple_build_assign (name, fetch); |
1093 | } | |
b6e99746 | 1094 | |
726a989a | 1095 | gsi_insert_before (&gsi, load, GSI_SAME_STMT); |
7156c8ab | 1096 | update_stmt (load); |
fade902a | 1097 | info->arr_ref_last = load; |
b6e99746 MJ |
1098 | } |
1099 | ||
1100 | /* Builds and initializes static arrays initialized with values gathered from | |
1101 | the SWTCH switch statement. Also creates statements that load values from | |
1102 | them. */ | |
1103 | ||
1104 | static void | |
fade902a | 1105 | build_arrays (gimple swtch, struct switch_conv_info *info) |
b6e99746 MJ |
1106 | { |
1107 | tree arr_index_type; | |
83d5977e | 1108 | tree tidx, sub, utype; |
726a989a RB |
1109 | gimple stmt; |
1110 | gimple_stmt_iterator gsi; | |
b6e99746 | 1111 | int i; |
db3927fb | 1112 | location_t loc = gimple_location (swtch); |
b6e99746 | 1113 | |
726a989a | 1114 | gsi = gsi_for_stmt (swtch); |
04e78aa9 | 1115 | |
edb9b69e | 1116 | /* Make sure we do not generate arithmetics in a subrange. */ |
fade902a | 1117 | utype = TREE_TYPE (info->index_expr); |
edb9b69e JJ |
1118 | if (TREE_TYPE (utype)) |
1119 | utype = lang_hooks.types.type_for_mode (TYPE_MODE (TREE_TYPE (utype)), 1); | |
1120 | else | |
1121 | utype = lang_hooks.types.type_for_mode (TYPE_MODE (utype), 1); | |
1122 | ||
fade902a | 1123 | arr_index_type = build_index_type (info->range_size); |
83d5977e | 1124 | tidx = make_ssa_name (utype, NULL); |
edb9b69e | 1125 | sub = fold_build2_loc (loc, MINUS_EXPR, utype, |
fade902a SB |
1126 | fold_convert_loc (loc, utype, info->index_expr), |
1127 | fold_convert_loc (loc, utype, info->range_min)); | |
fae1034e | 1128 | sub = force_gimple_operand_gsi (&gsi, sub, |
726a989a RB |
1129 | false, NULL, true, GSI_SAME_STMT); |
1130 | stmt = gimple_build_assign (tidx, sub); | |
b6e99746 | 1131 | |
726a989a | 1132 | gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); |
7156c8ab | 1133 | update_stmt (stmt); |
fade902a | 1134 | info->arr_ref_first = stmt; |
b6e99746 | 1135 | |
fade902a | 1136 | for (gsi = gsi_start_phis (info->final_bb), i = 0; |
726a989a | 1137 | !gsi_end_p (gsi); gsi_next (&gsi), i++) |
fade902a | 1138 | build_one_array (swtch, i, arr_index_type, gsi_stmt (gsi), tidx, info); |
b6e99746 MJ |
1139 | } |
1140 | ||
1141 | /* Generates and appropriately inserts loads of default values at the position | |
1142 | given by BSI. Returns the last inserted statement. */ | |
1143 | ||
726a989a | 1144 | static gimple |
fade902a | 1145 | gen_def_assigns (gimple_stmt_iterator *gsi, struct switch_conv_info *info) |
b6e99746 MJ |
1146 | { |
1147 | int i; | |
726a989a | 1148 | gimple assign = NULL; |
b6e99746 | 1149 | |
fade902a | 1150 | for (i = 0; i < info->phi_count; i++) |
b6e99746 | 1151 | { |
070ecdfd | 1152 | tree name = copy_ssa_name (info->target_inbound_names[i], NULL); |
fade902a SB |
1153 | info->target_outbound_names[i] = name; |
1154 | assign = gimple_build_assign (name, info->default_values[i]); | |
726a989a | 1155 | gsi_insert_before (gsi, assign, GSI_SAME_STMT); |
7156c8ab | 1156 | update_stmt (assign); |
b6e99746 MJ |
1157 | } |
1158 | return assign; | |
1159 | } | |
1160 | ||
1161 | /* Deletes the unused bbs and edges that now contain the switch statement and | |
1162 | its empty branch bbs. BBD is the now dead BB containing the original switch | |
1163 | statement, FINAL is the last BB of the converted switch statement (in terms | |
1164 | of succession). */ | |
1165 | ||
1166 | static void | |
1167 | prune_bbs (basic_block bbd, basic_block final) | |
1168 | { | |
1169 | edge_iterator ei; | |
1170 | edge e; | |
1171 | ||
1172 | for (ei = ei_start (bbd->succs); (e = ei_safe_edge (ei)); ) | |
1173 | { | |
1174 | basic_block bb; | |
1175 | bb = e->dest; | |
1176 | remove_edge (e); | |
1177 | if (bb != final) | |
1178 | delete_basic_block (bb); | |
1179 | } | |
1180 | delete_basic_block (bbd); | |
1181 | } | |
1182 | ||
1183 | /* Add values to phi nodes in final_bb for the two new edges. E1F is the edge | |
1184 | from the basic block loading values from an array and E2F from the basic | |
1185 | block loading default values. BBF is the last switch basic block (see the | |
1186 | bbf description in the comment below). */ | |
1187 | ||
1188 | static void | |
fade902a SB |
1189 | fix_phi_nodes (edge e1f, edge e2f, basic_block bbf, |
1190 | struct switch_conv_info *info) | |
b6e99746 | 1191 | { |
726a989a | 1192 | gimple_stmt_iterator gsi; |
b6e99746 MJ |
1193 | int i; |
1194 | ||
726a989a RB |
1195 | for (gsi = gsi_start_phis (bbf), i = 0; |
1196 | !gsi_end_p (gsi); gsi_next (&gsi), i++) | |
b6e99746 | 1197 | { |
726a989a | 1198 | gimple phi = gsi_stmt (gsi); |
9e227d60 DC |
1199 | add_phi_arg (phi, info->target_inbound_names[i], e1f, UNKNOWN_LOCATION); |
1200 | add_phi_arg (phi, info->target_outbound_names[i], e2f, UNKNOWN_LOCATION); | |
b6e99746 | 1201 | } |
b6e99746 MJ |
1202 | } |
1203 | ||
1204 | /* Creates a check whether the switch expression value actually falls into the | |
1205 | range given by all the cases. If it does not, the temporaries are loaded | |
1206 | with default values instead. SWTCH is the switch statement being converted. | |
1207 | ||
1208 | bb0 is the bb with the switch statement, however, we'll end it with a | |
1209 | condition instead. | |
1210 | ||
1211 | bb1 is the bb to be used when the range check went ok. It is derived from | |
1212 | the switch BB | |
1213 | ||
1214 | bb2 is the bb taken when the expression evaluated outside of the range | |
1215 | covered by the created arrays. It is populated by loads of default | |
1216 | values. | |
1217 | ||
1218 | bbF is a fall through for both bb1 and bb2 and contains exactly what | |
1219 | originally followed the switch statement. | |
1220 | ||
1221 | bbD contains the switch statement (in the end). It is unreachable but we | |
1222 | still need to strip off its edges. | |
1223 | */ | |
1224 | ||
1225 | static void | |
fade902a | 1226 | gen_inbound_check (gimple swtch, struct switch_conv_info *info) |
b6e99746 | 1227 | { |
c2255bc4 AH |
1228 | tree label_decl1 = create_artificial_label (UNKNOWN_LOCATION); |
1229 | tree label_decl2 = create_artificial_label (UNKNOWN_LOCATION); | |
1230 | tree label_decl3 = create_artificial_label (UNKNOWN_LOCATION); | |
726a989a | 1231 | gimple label1, label2, label3; |
edb9b69e | 1232 | tree utype, tidx; |
b6e99746 MJ |
1233 | tree bound; |
1234 | ||
726a989a | 1235 | gimple cond_stmt; |
b6e99746 | 1236 | |
726a989a RB |
1237 | gimple last_assign; |
1238 | gimple_stmt_iterator gsi; | |
b6e99746 MJ |
1239 | basic_block bb0, bb1, bb2, bbf, bbd; |
1240 | edge e01, e02, e21, e1d, e1f, e2f; | |
db3927fb | 1241 | location_t loc = gimple_location (swtch); |
b6e99746 | 1242 | |
fade902a | 1243 | gcc_assert (info->default_values); |
6ab1ab14 | 1244 | |
726a989a | 1245 | bb0 = gimple_bb (swtch); |
b6e99746 | 1246 | |
fade902a | 1247 | tidx = gimple_assign_lhs (info->arr_ref_first); |
edb9b69e | 1248 | utype = TREE_TYPE (tidx); |
145544ab | 1249 | |
b6e99746 | 1250 | /* (end of) block 0 */ |
fade902a | 1251 | gsi = gsi_for_stmt (info->arr_ref_first); |
edb9b69e | 1252 | gsi_next (&gsi); |
b6e99746 | 1253 | |
fade902a | 1254 | bound = fold_convert_loc (loc, utype, info->range_size); |
edb9b69e | 1255 | cond_stmt = gimple_build_cond (LE_EXPR, tidx, bound, NULL_TREE, NULL_TREE); |
726a989a | 1256 | gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT); |
7156c8ab | 1257 | update_stmt (cond_stmt); |
b6e99746 MJ |
1258 | |
1259 | /* block 2 */ | |
726a989a RB |
1260 | label2 = gimple_build_label (label_decl2); |
1261 | gsi_insert_before (&gsi, label2, GSI_SAME_STMT); | |
fade902a | 1262 | last_assign = gen_def_assigns (&gsi, info); |
b6e99746 MJ |
1263 | |
1264 | /* block 1 */ | |
726a989a RB |
1265 | label1 = gimple_build_label (label_decl1); |
1266 | gsi_insert_before (&gsi, label1, GSI_SAME_STMT); | |
b6e99746 MJ |
1267 | |
1268 | /* block F */ | |
fade902a | 1269 | gsi = gsi_start_bb (info->final_bb); |
726a989a RB |
1270 | label3 = gimple_build_label (label_decl3); |
1271 | gsi_insert_before (&gsi, label3, GSI_SAME_STMT); | |
b6e99746 MJ |
1272 | |
1273 | /* cfg fix */ | |
726a989a | 1274 | e02 = split_block (bb0, cond_stmt); |
b6e99746 MJ |
1275 | bb2 = e02->dest; |
1276 | ||
1277 | e21 = split_block (bb2, last_assign); | |
1278 | bb1 = e21->dest; | |
1279 | remove_edge (e21); | |
1280 | ||
fade902a | 1281 | e1d = split_block (bb1, info->arr_ref_last); |
b6e99746 MJ |
1282 | bbd = e1d->dest; |
1283 | remove_edge (e1d); | |
1284 | ||
1285 | /* flags and profiles of the edge for in-range values */ | |
1286 | e01 = make_edge (bb0, bb1, EDGE_TRUE_VALUE); | |
fade902a SB |
1287 | e01->probability = REG_BR_PROB_BASE - info->default_prob; |
1288 | e01->count = info->other_count; | |
b6e99746 MJ |
1289 | |
1290 | /* flags and profiles of the edge taking care of out-of-range values */ | |
1291 | e02->flags &= ~EDGE_FALLTHRU; | |
1292 | e02->flags |= EDGE_FALSE_VALUE; | |
fade902a SB |
1293 | e02->probability = info->default_prob; |
1294 | e02->count = info->default_count; | |
b6e99746 | 1295 | |
fade902a | 1296 | bbf = info->final_bb; |
b6e99746 MJ |
1297 | |
1298 | e1f = make_edge (bb1, bbf, EDGE_FALLTHRU); | |
1299 | e1f->probability = REG_BR_PROB_BASE; | |
fade902a | 1300 | e1f->count = info->other_count; |
b6e99746 MJ |
1301 | |
1302 | e2f = make_edge (bb2, bbf, EDGE_FALLTHRU); | |
1303 | e2f->probability = REG_BR_PROB_BASE; | |
fade902a | 1304 | e2f->count = info->default_count; |
b6e99746 MJ |
1305 | |
1306 | /* frequencies of the new BBs */ | |
1307 | bb1->frequency = EDGE_FREQUENCY (e01); | |
1308 | bb2->frequency = EDGE_FREQUENCY (e02); | |
1309 | bbf->frequency = EDGE_FREQUENCY (e1f) + EDGE_FREQUENCY (e2f); | |
1310 | ||
6ab1ab14 SB |
1311 | /* Tidy blocks that have become unreachable. */ |
1312 | prune_bbs (bbd, info->final_bb); | |
b6e99746 | 1313 | |
6ab1ab14 | 1314 | /* Fixup the PHI nodes in bbF. */ |
fade902a | 1315 | fix_phi_nodes (e1f, e2f, bbf, info); |
b6e99746 | 1316 | |
6ab1ab14 SB |
1317 | /* Fix the dominator tree, if it is available. */ |
1318 | if (dom_info_available_p (CDI_DOMINATORS)) | |
1319 | { | |
9771b263 | 1320 | vec<basic_block> bbs_to_fix_dom; |
6ab1ab14 SB |
1321 | |
1322 | set_immediate_dominator (CDI_DOMINATORS, bb1, bb0); | |
1323 | set_immediate_dominator (CDI_DOMINATORS, bb2, bb0); | |
531b10fc | 1324 | if (! get_immediate_dominator (CDI_DOMINATORS, bbf)) |
6ab1ab14 SB |
1325 | /* If bbD was the immediate dominator ... */ |
1326 | set_immediate_dominator (CDI_DOMINATORS, bbf, bb0); | |
1327 | ||
9771b263 DN |
1328 | bbs_to_fix_dom.create (4); |
1329 | bbs_to_fix_dom.quick_push (bb0); | |
1330 | bbs_to_fix_dom.quick_push (bb1); | |
1331 | bbs_to_fix_dom.quick_push (bb2); | |
1332 | bbs_to_fix_dom.quick_push (bbf); | |
6ab1ab14 SB |
1333 | |
1334 | iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
9771b263 | 1335 | bbs_to_fix_dom.release (); |
6ab1ab14 | 1336 | } |
b6e99746 MJ |
1337 | } |
1338 | ||
1339 | /* The following function is invoked on every switch statement (the current one | |
1340 | is given in SWTCH) and runs the individual phases of switch conversion on it | |
fade902a SB |
1341 | one after another until one fails or the conversion is completed. |
1342 | Returns NULL on success, or a pointer to a string with the reason why the | |
1343 | conversion failed. */ | |
b6e99746 | 1344 | |
fade902a | 1345 | static const char * |
726a989a | 1346 | process_switch (gimple swtch) |
b6e99746 | 1347 | { |
fade902a | 1348 | struct switch_conv_info info; |
b6e99746 | 1349 | |
238065a7 SB |
1350 | /* Group case labels so that we get the right results from the heuristics |
1351 | that decide on the code generation approach for this switch. */ | |
1352 | group_case_labels_stmt (swtch); | |
1353 | ||
1354 | /* If this switch is now a degenerate case with only a default label, | |
1355 | there is nothing left for us to do. */ | |
1356 | if (gimple_switch_num_labels (swtch) < 2) | |
1357 | return "switch is a degenerate case"; | |
886cd84f SB |
1358 | |
1359 | collect_switch_conv_info (swtch, &info); | |
1360 | ||
1361 | /* No error markers should reach here (they should be filtered out | |
1362 | during gimplification). */ | |
1363 | gcc_checking_assert (TREE_TYPE (info.index_expr) != error_mark_node); | |
1364 | ||
531b10fc SB |
1365 | /* A switch on a constant should have been optimized in tree-cfg-cleanup. */ |
1366 | gcc_checking_assert (! TREE_CONSTANT (info.index_expr)); | |
886cd84f | 1367 | |
531b10fc | 1368 | if (info.uniq <= MAX_CASE_BIT_TESTS) |
886cd84f | 1369 | { |
531b10fc | 1370 | if (expand_switch_using_bit_tests_p (info.range_size, |
72798784 RB |
1371 | info.uniq, info.count, |
1372 | optimize_bb_for_speed_p | |
1373 | (gimple_bb (swtch)))) | |
531b10fc SB |
1374 | { |
1375 | if (dump_file) | |
1376 | fputs (" expanding as bit test is preferable\n", dump_file); | |
aa79a1e1 JJ |
1377 | emit_case_bit_tests (swtch, info.index_expr, info.range_min, |
1378 | info.range_size, info.range_max); | |
726338f4 | 1379 | loops_state_set (LOOPS_NEED_FIXUP); |
531b10fc SB |
1380 | return NULL; |
1381 | } | |
1382 | ||
1383 | if (info.uniq <= 2) | |
1384 | /* This will be expanded as a decision tree in stmt.c:expand_case. */ | |
1385 | return " expanding as jumps is preferable"; | |
886cd84f | 1386 | } |
b6e99746 | 1387 | |
531b10fc SB |
1388 | /* If there is no common successor, we cannot do the transformation. */ |
1389 | if (! info.final_bb) | |
1390 | return "no common successor to all case label target blocks found"; | |
1391 | ||
b6e99746 | 1392 | /* Check the case label values are within reasonable range: */ |
886cd84f | 1393 | if (!check_range (&info)) |
fade902a SB |
1394 | { |
1395 | gcc_assert (info.reason); | |
1396 | return info.reason; | |
1397 | } | |
b6e99746 MJ |
1398 | |
1399 | /* For all the cases, see whether they are empty, the assignments they | |
1400 | represent constant and so on... */ | |
886cd84f | 1401 | if (! check_all_empty_except_final (&info)) |
8e97bc2b | 1402 | { |
886cd84f SB |
1403 | gcc_assert (info.reason); |
1404 | return info.reason; | |
8e97bc2b | 1405 | } |
fade902a SB |
1406 | if (!check_final_bb (&info)) |
1407 | { | |
1408 | gcc_assert (info.reason); | |
1409 | return info.reason; | |
1410 | } | |
b6e99746 MJ |
1411 | |
1412 | /* At this point all checks have passed and we can proceed with the | |
1413 | transformation. */ | |
1414 | ||
fade902a | 1415 | create_temp_arrays (&info); |
fd8d363e | 1416 | gather_default_values (gimple_switch_default_label (swtch), &info); |
fade902a | 1417 | build_constructors (swtch, &info); |
b6e99746 | 1418 | |
fade902a SB |
1419 | build_arrays (swtch, &info); /* Build the static arrays and assignments. */ |
1420 | gen_inbound_check (swtch, &info); /* Build the bounds check. */ | |
b6e99746 MJ |
1421 | |
1422 | /* Cleanup: */ | |
fade902a SB |
1423 | free_temp_arrays (&info); |
1424 | return NULL; | |
b6e99746 MJ |
1425 | } |
1426 | ||
1427 | /* The main function of the pass scans statements for switches and invokes | |
1428 | process_switch on them. */ | |
1429 | ||
be55bfe6 TS |
1430 | namespace { |
1431 | ||
1432 | const pass_data pass_data_convert_switch = | |
1433 | { | |
1434 | GIMPLE_PASS, /* type */ | |
1435 | "switchconv", /* name */ | |
1436 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
1437 | TV_TREE_SWITCH_CONVERSION, /* tv_id */ |
1438 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1439 | 0, /* properties_provided */ | |
1440 | 0, /* properties_destroyed */ | |
1441 | 0, /* todo_flags_start */ | |
3bea341f | 1442 | TODO_update_ssa, /* todo_flags_finish */ |
be55bfe6 TS |
1443 | }; |
1444 | ||
1445 | class pass_convert_switch : public gimple_opt_pass | |
1446 | { | |
1447 | public: | |
1448 | pass_convert_switch (gcc::context *ctxt) | |
1449 | : gimple_opt_pass (pass_data_convert_switch, ctxt) | |
1450 | {} | |
1451 | ||
1452 | /* opt_pass methods: */ | |
1453 | virtual bool gate (function *) { return flag_tree_switch_conversion != 0; } | |
1454 | virtual unsigned int execute (function *); | |
1455 | ||
1456 | }; // class pass_convert_switch | |
1457 | ||
1458 | unsigned int | |
1459 | pass_convert_switch::execute (function *fun) | |
b6e99746 MJ |
1460 | { |
1461 | basic_block bb; | |
1462 | ||
be55bfe6 | 1463 | FOR_EACH_BB_FN (bb, fun) |
b6e99746 | 1464 | { |
fade902a | 1465 | const char *failure_reason; |
726a989a RB |
1466 | gimple stmt = last_stmt (bb); |
1467 | if (stmt && gimple_code (stmt) == GIMPLE_SWITCH) | |
b6e99746 | 1468 | { |
b6e99746 MJ |
1469 | if (dump_file) |
1470 | { | |
726a989a RB |
1471 | expanded_location loc = expand_location (gimple_location (stmt)); |
1472 | ||
b6e99746 MJ |
1473 | fprintf (dump_file, "beginning to process the following " |
1474 | "SWITCH statement (%s:%d) : ------- \n", | |
1475 | loc.file, loc.line); | |
726a989a | 1476 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
edb30094 | 1477 | putc ('\n', dump_file); |
b6e99746 MJ |
1478 | } |
1479 | ||
fade902a SB |
1480 | failure_reason = process_switch (stmt); |
1481 | if (! failure_reason) | |
b6e99746 MJ |
1482 | { |
1483 | if (dump_file) | |
1484 | { | |
edb30094 UB |
1485 | fputs ("Switch converted\n", dump_file); |
1486 | fputs ("--------------------------------\n", dump_file); | |
b6e99746 | 1487 | } |
531b10fc SB |
1488 | |
1489 | /* Make no effort to update the post-dominator tree. It is actually not | |
1490 | that hard for the transformations we have performed, but it is not | |
1491 | supported by iterate_fix_dominators. */ | |
1492 | free_dominance_info (CDI_POST_DOMINATORS); | |
b6e99746 MJ |
1493 | } |
1494 | else | |
1495 | { | |
1496 | if (dump_file) | |
1497 | { | |
edb30094 | 1498 | fputs ("Bailing out - ", dump_file); |
fade902a SB |
1499 | fputs (failure_reason, dump_file); |
1500 | fputs ("\n--------------------------------\n", dump_file); | |
b6e99746 MJ |
1501 | } |
1502 | } | |
1503 | } | |
1504 | } | |
1505 | ||
1506 | return 0; | |
1507 | } | |
1508 | ||
27a4cd48 DM |
1509 | } // anon namespace |
1510 | ||
1511 | gimple_opt_pass * | |
1512 | make_pass_convert_switch (gcc::context *ctxt) | |
1513 | { | |
1514 | return new pass_convert_switch (ctxt); | |
1515 | } |