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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. | |
5624e564 | 3 | Copyright (C) 2006-2015 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 SB |
39 | #include "params.h" |
40 | #include "flags.h" | |
40e23961 | 41 | #include "alias.h" |
40e23961 | 42 | #include "fold-const.h" |
d8a2d370 DN |
43 | #include "varasm.h" |
44 | #include "stor-layout.h" | |
60393bbc | 45 | #include "cfganal.h" |
2fb9a547 | 46 | #include "internal-fn.h" |
45b0be94 | 47 | #include "gimplify.h" |
5be5c238 | 48 | #include "gimple-iterator.h" |
18f429e2 | 49 | #include "gimplify-me.h" |
442b4905 | 50 | #include "tree-cfg.h" |
a9e0d843 | 51 | #include "cfgloop.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; | |
109 | e_false->probability = REG_BR_PROB_BASE - e_true->probability; | |
110 | e_false->count = split_bb->count - e_true->count; | |
111 | new_bb->count = e_false->count; | |
112 | ||
113 | if (update_dominators) | |
114 | { | |
115 | if (dominated_e_true) | |
116 | set_immediate_dominator (CDI_DOMINATORS, e_true->dest, split_bb); | |
117 | set_immediate_dominator (CDI_DOMINATORS, e_false->dest, split_bb); | |
118 | } | |
119 | ||
120 | return new_bb; | |
121 | } | |
122 | ||
123 | ||
531b10fc SB |
124 | /* Return true if a switch should be expanded as a bit test. |
125 | RANGE is the difference between highest and lowest case. | |
126 | UNIQ is number of unique case node targets, not counting the default case. | |
127 | COUNT is the number of comparisons needed, not counting the default case. */ | |
128 | ||
129 | static bool | |
130 | expand_switch_using_bit_tests_p (tree range, | |
131 | unsigned int uniq, | |
72798784 | 132 | unsigned int count, bool speed_p) |
531b10fc SB |
133 | { |
134 | return (((uniq == 1 && count >= 3) | |
135 | || (uniq == 2 && count >= 5) | |
136 | || (uniq == 3 && count >= 6)) | |
72798784 | 137 | && lshift_cheap_p (speed_p) |
531b10fc SB |
138 | && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0 |
139 | && compare_tree_int (range, 0) > 0); | |
140 | } | |
141 | \f | |
142 | /* Implement switch statements with bit tests | |
143 | ||
144 | A GIMPLE switch statement can be expanded to a short sequence of bit-wise | |
145 | comparisons. "switch(x)" is converted into "if ((1 << (x-MINVAL)) & CST)" | |
146 | where CST and MINVAL are integer constants. This is better than a series | |
147 | of compare-and-banch insns in some cases, e.g. we can implement: | |
148 | ||
149 | if ((x==4) || (x==6) || (x==9) || (x==11)) | |
150 | ||
151 | as a single bit test: | |
152 | ||
153 | if ((1<<x) & ((1<<4)|(1<<6)|(1<<9)|(1<<11))) | |
154 | ||
155 | This transformation is only applied if the number of case targets is small, | |
34540577 | 156 | if CST constains at least 3 bits, and "1 << x" is cheap. The bit tests are |
531b10fc SB |
157 | performed in "word_mode". |
158 | ||
159 | The following example shows the code the transformation generates: | |
160 | ||
161 | int bar(int x) | |
162 | { | |
163 | switch (x) | |
164 | { | |
165 | case '0': case '1': case '2': case '3': case '4': | |
166 | case '5': case '6': case '7': case '8': case '9': | |
167 | case 'A': case 'B': case 'C': case 'D': case 'E': | |
168 | case 'F': | |
169 | return 1; | |
170 | } | |
171 | return 0; | |
172 | } | |
173 | ||
174 | ==> | |
175 | ||
176 | bar (int x) | |
177 | { | |
178 | tmp1 = x - 48; | |
179 | if (tmp1 > (70 - 48)) goto L2; | |
180 | tmp2 = 1 << tmp1; | |
181 | tmp3 = 0b11111100000001111111111; | |
182 | if ((tmp2 & tmp3) != 0) goto L1 ; else goto L2; | |
183 | L1: | |
184 | return 1; | |
185 | L2: | |
186 | return 0; | |
187 | } | |
188 | ||
189 | TODO: There are still some improvements to this transformation that could | |
190 | be implemented: | |
191 | ||
192 | * A narrower mode than word_mode could be used if that is cheaper, e.g. | |
193 | for x86_64 where a narrower-mode shift may result in smaller code. | |
194 | ||
195 | * The compounded constant could be shifted rather than the one. The | |
196 | test would be either on the sign bit or on the least significant bit, | |
197 | depending on the direction of the shift. On some machines, the test | |
198 | for the branch would be free if the bit to test is already set by the | |
199 | shift operation. | |
200 | ||
201 | This transformation was contributed by Roger Sayle, see this e-mail: | |
202 | http://gcc.gnu.org/ml/gcc-patches/2003-01/msg01950.html | |
203 | */ | |
204 | ||
205 | /* A case_bit_test represents a set of case nodes that may be | |
206 | selected from using a bit-wise comparison. HI and LO hold | |
207 | the integer to be tested against, TARGET_EDGE contains the | |
208 | edge to the basic block to jump to upon success and BITS | |
209 | counts the number of case nodes handled by this test, | |
210 | typically the number of bits set in HI:LO. The LABEL field | |
211 | is used to quickly identify all cases in this set without | |
212 | looking at label_to_block for every case label. */ | |
213 | ||
214 | struct case_bit_test | |
215 | { | |
aa79a1e1 | 216 | wide_int mask; |
531b10fc SB |
217 | edge target_edge; |
218 | tree label; | |
219 | int bits; | |
220 | }; | |
221 | ||
222 | /* Comparison function for qsort to order bit tests by decreasing | |
223 | probability of execution. Our best guess comes from a measured | |
224 | profile. If the profile counts are equal, break even on the | |
225 | number of case nodes, i.e. the node with the most cases gets | |
226 | tested first. | |
227 | ||
228 | TODO: Actually this currently runs before a profile is available. | |
229 | Therefore the case-as-bit-tests transformation should be done | |
230 | later in the pass pipeline, or something along the lines of | |
231 | "Efficient and effective branch reordering using profile data" | |
232 | (Yang et. al., 2002) should be implemented (although, how good | |
233 | is a paper is called "Efficient and effective ..." when the | |
234 | latter is implied by the former, but oh well...). */ | |
235 | ||
236 | static int | |
237 | case_bit_test_cmp (const void *p1, const void *p2) | |
238 | { | |
239 | const struct case_bit_test *const d1 = (const struct case_bit_test *) p1; | |
240 | const struct case_bit_test *const d2 = (const struct case_bit_test *) p2; | |
241 | ||
242 | if (d2->target_edge->count != d1->target_edge->count) | |
243 | return d2->target_edge->count - d1->target_edge->count; | |
244 | if (d2->bits != d1->bits) | |
245 | return d2->bits - d1->bits; | |
246 | ||
247 | /* Stabilize the sort. */ | |
248 | return LABEL_DECL_UID (d2->label) - LABEL_DECL_UID (d1->label); | |
249 | } | |
250 | ||
251 | /* Expand a switch statement by a short sequence of bit-wise | |
252 | comparisons. "switch(x)" is effectively converted into | |
253 | "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are | |
254 | integer constants. | |
255 | ||
256 | INDEX_EXPR is the value being switched on. | |
257 | ||
258 | MINVAL is the lowest case value of in the case nodes, | |
259 | and RANGE is highest value minus MINVAL. MINVAL and RANGE | |
260 | are not guaranteed to be of the same type as INDEX_EXPR | |
261 | (the gimplifier doesn't change the type of case label values, | |
262 | and MINVAL and RANGE are derived from those values). | |
aa79a1e1 | 263 | MAXVAL is MINVAL + RANGE. |
531b10fc SB |
264 | |
265 | There *MUST* be MAX_CASE_BIT_TESTS or less unique case | |
266 | node targets. */ | |
267 | ||
268 | static void | |
538dd0b7 | 269 | emit_case_bit_tests (gswitch *swtch, tree index_expr, |
aa79a1e1 | 270 | tree minval, tree range, tree maxval) |
531b10fc SB |
271 | { |
272 | struct case_bit_test test[MAX_CASE_BIT_TESTS]; | |
273 | unsigned int i, j, k; | |
274 | unsigned int count; | |
275 | ||
276 | basic_block switch_bb = gimple_bb (swtch); | |
277 | basic_block default_bb, new_default_bb, new_bb; | |
278 | edge default_edge; | |
279 | bool update_dom = dom_info_available_p (CDI_DOMINATORS); | |
280 | ||
6e1aa848 | 281 | vec<basic_block> bbs_to_fix_dom = vNULL; |
531b10fc SB |
282 | |
283 | tree index_type = TREE_TYPE (index_expr); | |
284 | tree unsigned_index_type = unsigned_type_for (index_type); | |
285 | unsigned int branch_num = gimple_switch_num_labels (swtch); | |
286 | ||
287 | gimple_stmt_iterator gsi; | |
538dd0b7 | 288 | gassign *shift_stmt; |
531b10fc SB |
289 | |
290 | tree idx, tmp, csui; | |
291 | tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1); | |
292 | tree word_mode_zero = fold_convert (word_type_node, integer_zero_node); | |
293 | tree word_mode_one = fold_convert (word_type_node, integer_one_node); | |
aa79a1e1 JJ |
294 | int prec = TYPE_PRECISION (word_type_node); |
295 | wide_int wone = wi::one (prec); | |
531b10fc SB |
296 | |
297 | memset (&test, 0, sizeof (test)); | |
298 | ||
299 | /* Get the edge for the default case. */ | |
fd8d363e | 300 | tmp = gimple_switch_default_label (swtch); |
531b10fc SB |
301 | default_bb = label_to_block (CASE_LABEL (tmp)); |
302 | default_edge = find_edge (switch_bb, default_bb); | |
303 | ||
304 | /* Go through all case labels, and collect the case labels, profile | |
305 | counts, and other information we need to build the branch tests. */ | |
306 | count = 0; | |
307 | for (i = 1; i < branch_num; i++) | |
308 | { | |
309 | unsigned int lo, hi; | |
310 | tree cs = gimple_switch_label (swtch, i); | |
311 | tree label = CASE_LABEL (cs); | |
8166ff4d | 312 | edge e = find_edge (switch_bb, label_to_block (label)); |
531b10fc | 313 | for (k = 0; k < count; k++) |
8166ff4d | 314 | if (e == test[k].target_edge) |
531b10fc SB |
315 | break; |
316 | ||
317 | if (k == count) | |
318 | { | |
531b10fc | 319 | gcc_checking_assert (count < MAX_CASE_BIT_TESTS); |
aa79a1e1 | 320 | test[k].mask = wi::zero (prec); |
531b10fc SB |
321 | test[k].target_edge = e; |
322 | test[k].label = label; | |
323 | test[k].bits = 1; | |
324 | count++; | |
325 | } | |
326 | else | |
327 | test[k].bits++; | |
328 | ||
386b1f1f RS |
329 | lo = tree_to_uhwi (int_const_binop (MINUS_EXPR, |
330 | CASE_LOW (cs), minval)); | |
531b10fc SB |
331 | if (CASE_HIGH (cs) == NULL_TREE) |
332 | hi = lo; | |
333 | else | |
386b1f1f RS |
334 | hi = tree_to_uhwi (int_const_binop (MINUS_EXPR, |
335 | CASE_HIGH (cs), minval)); | |
531b10fc SB |
336 | |
337 | for (j = lo; j <= hi; j++) | |
aa79a1e1 | 338 | test[k].mask |= wi::lshift (wone, j); |
531b10fc SB |
339 | } |
340 | ||
c3284718 | 341 | qsort (test, count, sizeof (*test), case_bit_test_cmp); |
531b10fc | 342 | |
aa79a1e1 JJ |
343 | /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of |
344 | the minval subtractions, but it might make the mask constants more | |
345 | expensive. So, compare the costs. */ | |
346 | if (compare_tree_int (minval, 0) > 0 | |
347 | && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0) | |
348 | { | |
349 | int cost_diff; | |
350 | HOST_WIDE_INT m = tree_to_uhwi (minval); | |
351 | rtx reg = gen_raw_REG (word_mode, 10000); | |
352 | bool speed_p = optimize_bb_for_speed_p (gimple_bb (swtch)); | |
353 | cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg, | |
354 | GEN_INT (-m)), speed_p); | |
355 | for (i = 0; i < count; i++) | |
356 | { | |
357 | rtx r = immed_wide_int_const (test[i].mask, word_mode); | |
e548c9df AM |
358 | cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r), |
359 | word_mode, speed_p); | |
aa79a1e1 | 360 | r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode); |
e548c9df AM |
361 | cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r), |
362 | word_mode, speed_p); | |
aa79a1e1 JJ |
363 | } |
364 | if (cost_diff > 0) | |
365 | { | |
366 | for (i = 0; i < count; i++) | |
367 | test[i].mask = wi::lshift (test[i].mask, m); | |
368 | minval = build_zero_cst (TREE_TYPE (minval)); | |
369 | range = maxval; | |
370 | } | |
371 | } | |
372 | ||
531b10fc SB |
373 | /* We generate two jumps to the default case label. |
374 | Split the default edge, so that we don't have to do any PHI node | |
375 | updating. */ | |
376 | new_default_bb = split_edge (default_edge); | |
377 | ||
378 | if (update_dom) | |
379 | { | |
9771b263 DN |
380 | bbs_to_fix_dom.create (10); |
381 | bbs_to_fix_dom.quick_push (switch_bb); | |
382 | bbs_to_fix_dom.quick_push (default_bb); | |
383 | bbs_to_fix_dom.quick_push (new_default_bb); | |
531b10fc SB |
384 | } |
385 | ||
386 | /* Now build the test-and-branch code. */ | |
387 | ||
388 | gsi = gsi_last_bb (switch_bb); | |
389 | ||
d9e408de TV |
390 | /* idx = (unsigned)x - minval. */ |
391 | idx = fold_convert (unsigned_index_type, index_expr); | |
392 | idx = fold_build2 (MINUS_EXPR, unsigned_index_type, idx, | |
393 | fold_convert (unsigned_index_type, minval)); | |
531b10fc SB |
394 | idx = force_gimple_operand_gsi (&gsi, idx, |
395 | /*simple=*/true, NULL_TREE, | |
396 | /*before=*/true, GSI_SAME_STMT); | |
397 | ||
398 | /* if (idx > range) goto default */ | |
399 | range = force_gimple_operand_gsi (&gsi, | |
400 | fold_convert (unsigned_index_type, range), | |
401 | /*simple=*/true, NULL_TREE, | |
402 | /*before=*/true, GSI_SAME_STMT); | |
403 | tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range); | |
404 | new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, default_edge, update_dom); | |
405 | if (update_dom) | |
9771b263 | 406 | bbs_to_fix_dom.quick_push (new_bb); |
531b10fc SB |
407 | gcc_assert (gimple_bb (swtch) == new_bb); |
408 | gsi = gsi_last_bb (new_bb); | |
409 | ||
410 | /* Any blocks dominated by the GIMPLE_SWITCH, but that are not successors | |
411 | of NEW_BB, are still immediately dominated by SWITCH_BB. Make it so. */ | |
412 | if (update_dom) | |
413 | { | |
9771b263 | 414 | vec<basic_block> dom_bbs; |
531b10fc SB |
415 | basic_block dom_son; |
416 | ||
417 | dom_bbs = get_dominated_by (CDI_DOMINATORS, new_bb); | |
9771b263 | 418 | FOR_EACH_VEC_ELT (dom_bbs, i, dom_son) |
531b10fc SB |
419 | { |
420 | edge e = find_edge (new_bb, dom_son); | |
421 | if (e && single_pred_p (e->dest)) | |
422 | continue; | |
423 | set_immediate_dominator (CDI_DOMINATORS, dom_son, switch_bb); | |
9771b263 | 424 | bbs_to_fix_dom.safe_push (dom_son); |
531b10fc | 425 | } |
9771b263 | 426 | dom_bbs.release (); |
531b10fc SB |
427 | } |
428 | ||
429 | /* csui = (1 << (word_mode) idx) */ | |
b731b390 | 430 | csui = make_ssa_name (word_type_node); |
531b10fc SB |
431 | tmp = fold_build2 (LSHIFT_EXPR, word_type_node, word_mode_one, |
432 | fold_convert (word_type_node, idx)); | |
433 | tmp = force_gimple_operand_gsi (&gsi, tmp, | |
434 | /*simple=*/false, NULL_TREE, | |
435 | /*before=*/true, GSI_SAME_STMT); | |
436 | shift_stmt = gimple_build_assign (csui, tmp); | |
531b10fc SB |
437 | gsi_insert_before (&gsi, shift_stmt, GSI_SAME_STMT); |
438 | update_stmt (shift_stmt); | |
439 | ||
440 | /* for each unique set of cases: | |
441 | if (const & csui) goto target */ | |
442 | for (k = 0; k < count; k++) | |
443 | { | |
aa79a1e1 | 444 | tmp = wide_int_to_tree (word_type_node, test[k].mask); |
531b10fc SB |
445 | tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp); |
446 | tmp = force_gimple_operand_gsi (&gsi, tmp, | |
447 | /*simple=*/true, NULL_TREE, | |
448 | /*before=*/true, GSI_SAME_STMT); | |
449 | tmp = fold_build2 (NE_EXPR, boolean_type_node, tmp, word_mode_zero); | |
450 | new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, test[k].target_edge, | |
451 | update_dom); | |
452 | if (update_dom) | |
9771b263 | 453 | bbs_to_fix_dom.safe_push (new_bb); |
531b10fc SB |
454 | gcc_assert (gimple_bb (swtch) == new_bb); |
455 | gsi = gsi_last_bb (new_bb); | |
456 | } | |
457 | ||
458 | /* We should have removed all edges now. */ | |
459 | gcc_assert (EDGE_COUNT (gsi_bb (gsi)->succs) == 0); | |
460 | ||
461 | /* If nothing matched, go to the default label. */ | |
462 | make_edge (gsi_bb (gsi), new_default_bb, EDGE_FALLTHRU); | |
463 | ||
464 | /* The GIMPLE_SWITCH is now redundant. */ | |
465 | gsi_remove (&gsi, true); | |
466 | ||
467 | if (update_dom) | |
468 | { | |
469 | /* Fix up the dominator tree. */ | |
470 | iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
9771b263 | 471 | bbs_to_fix_dom.release (); |
531b10fc SB |
472 | } |
473 | } | |
474 | \f | |
b6e99746 MJ |
475 | /* |
476 | Switch initialization conversion | |
477 | ||
478 | The following pass changes simple initializations of scalars in a switch | |
fade902a SB |
479 | statement into initializations from a static array. Obviously, the values |
480 | must be constant and known at compile time and a default branch must be | |
b6e99746 MJ |
481 | provided. For example, the following code: |
482 | ||
483 | int a,b; | |
484 | ||
485 | switch (argc) | |
486 | { | |
487 | case 1: | |
488 | case 2: | |
489 | a_1 = 8; | |
490 | b_1 = 6; | |
491 | break; | |
492 | case 3: | |
493 | a_2 = 9; | |
494 | b_2 = 5; | |
495 | break; | |
496 | case 12: | |
497 | a_3 = 10; | |
498 | b_3 = 4; | |
499 | break; | |
500 | default: | |
501 | a_4 = 16; | |
502 | b_4 = 1; | |
886cd84f | 503 | break; |
b6e99746 MJ |
504 | } |
505 | a_5 = PHI <a_1, a_2, a_3, a_4> | |
506 | b_5 = PHI <b_1, b_2, b_3, b_4> | |
507 | ||
508 | ||
509 | is changed into: | |
510 | ||
511 | static const int = CSWTCH01[] = {6, 6, 5, 1, 1, 1, 1, 1, 1, 1, 1, 4}; | |
512 | static const int = CSWTCH02[] = {8, 8, 9, 16, 16, 16, 16, 16, 16, 16, | |
513 | 16, 16, 10}; | |
514 | ||
515 | if (((unsigned) argc) - 1 < 11) | |
516 | { | |
517 | a_6 = CSWTCH02[argc - 1]; | |
518 | b_6 = CSWTCH01[argc - 1]; | |
519 | } | |
520 | else | |
521 | { | |
522 | a_7 = 16; | |
523 | b_7 = 1; | |
524 | } | |
886cd84f SB |
525 | a_5 = PHI <a_6, a_7> |
526 | b_b = PHI <b_6, b_7> | |
b6e99746 MJ |
527 | |
528 | There are further constraints. Specifically, the range of values across all | |
529 | case labels must not be bigger than SWITCH_CONVERSION_BRANCH_RATIO (default | |
531b10fc | 530 | eight) times the number of the actual switch branches. |
b6e99746 | 531 | |
531b10fc SB |
532 | This transformation was contributed by Martin Jambor, see this e-mail: |
533 | http://gcc.gnu.org/ml/gcc-patches/2008-07/msg00011.html */ | |
b6e99746 MJ |
534 | |
535 | /* The main structure of the pass. */ | |
536 | struct switch_conv_info | |
537 | { | |
886cd84f | 538 | /* The expression used to decide the switch branch. */ |
b6e99746 MJ |
539 | tree index_expr; |
540 | ||
886cd84f SB |
541 | /* The following integer constants store the minimum and maximum value |
542 | covered by the case labels. */ | |
b6e99746 | 543 | tree range_min; |
886cd84f | 544 | tree range_max; |
b6e99746 | 545 | |
886cd84f SB |
546 | /* The difference between the above two numbers. Stored here because it |
547 | is used in all the conversion heuristics, as well as for some of the | |
548 | transformation, and it is expensive to re-compute it all the time. */ | |
b6e99746 MJ |
549 | tree range_size; |
550 | ||
886cd84f | 551 | /* Basic block that contains the actual GIMPLE_SWITCH. */ |
b6e99746 MJ |
552 | basic_block switch_bb; |
553 | ||
886cd84f SB |
554 | /* Basic block that is the target of the default case. */ |
555 | basic_block default_bb; | |
556 | ||
557 | /* The single successor block of all branches out of the GIMPLE_SWITCH, | |
558 | if such a block exists. Otherwise NULL. */ | |
b6e99746 MJ |
559 | basic_block final_bb; |
560 | ||
886cd84f SB |
561 | /* The probability of the default edge in the replaced switch. */ |
562 | int default_prob; | |
563 | ||
564 | /* The count of the default edge in the replaced switch. */ | |
565 | gcov_type default_count; | |
566 | ||
567 | /* Combined count of all other (non-default) edges in the replaced switch. */ | |
568 | gcov_type other_count; | |
569 | ||
b6e99746 MJ |
570 | /* Number of phi nodes in the final bb (that we'll be replacing). */ |
571 | int phi_count; | |
572 | ||
b1ae1681 | 573 | /* Array of default values, in the same order as phi nodes. */ |
b6e99746 MJ |
574 | tree *default_values; |
575 | ||
576 | /* Constructors of new static arrays. */ | |
9771b263 | 577 | vec<constructor_elt, va_gc> **constructors; |
b6e99746 MJ |
578 | |
579 | /* Array of ssa names that are initialized with a value from a new static | |
580 | array. */ | |
581 | tree *target_inbound_names; | |
582 | ||
583 | /* Array of ssa names that are initialized with the default value if the | |
584 | switch expression is out of range. */ | |
585 | tree *target_outbound_names; | |
586 | ||
b1ae1681 MJ |
587 | /* The first load statement that loads a temporary from a new static array. |
588 | */ | |
355fe088 | 589 | gimple *arr_ref_first; |
b6e99746 MJ |
590 | |
591 | /* The last load statement that loads a temporary from a new static array. */ | |
355fe088 | 592 | gimple *arr_ref_last; |
b6e99746 MJ |
593 | |
594 | /* String reason why the case wasn't a good candidate that is written to the | |
595 | dump file, if there is one. */ | |
596 | const char *reason; | |
8e97bc2b JJ |
597 | |
598 | /* Parameters for expand_switch_using_bit_tests. Should be computed | |
599 | the same way as in expand_case. */ | |
886cd84f SB |
600 | unsigned int uniq; |
601 | unsigned int count; | |
b6e99746 MJ |
602 | }; |
603 | ||
886cd84f | 604 | /* Collect information about GIMPLE_SWITCH statement SWTCH into INFO. */ |
b6e99746 | 605 | |
886cd84f | 606 | static void |
538dd0b7 | 607 | collect_switch_conv_info (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 | 608 | { |
726a989a | 609 | unsigned int branch_num = gimple_switch_num_labels (swtch); |
886cd84f SB |
610 | tree min_case, max_case; |
611 | unsigned int count, i; | |
612 | edge e, e_default; | |
613 | edge_iterator ei; | |
614 | ||
615 | memset (info, 0, sizeof (*info)); | |
b6e99746 MJ |
616 | |
617 | /* The gimplifier has already sorted the cases by CASE_LOW and ensured there | |
fd8d363e SB |
618 | is a default label which is the first in the vector. |
619 | Collect the bits we can deduce from the CFG. */ | |
886cd84f SB |
620 | info->index_expr = gimple_switch_index (swtch); |
621 | info->switch_bb = gimple_bb (swtch); | |
622 | info->default_bb = | |
fd8d363e | 623 | label_to_block (CASE_LABEL (gimple_switch_default_label (swtch))); |
886cd84f SB |
624 | e_default = find_edge (info->switch_bb, info->default_bb); |
625 | info->default_prob = e_default->probability; | |
626 | info->default_count = e_default->count; | |
627 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
628 | if (e != e_default) | |
629 | info->other_count += e->count; | |
b6e99746 | 630 | |
886cd84f | 631 | /* See if there is one common successor block for all branch |
866f20d6 RB |
632 | targets. If it exists, record it in FINAL_BB. |
633 | Start with the destination of the default case as guess | |
634 | or its destination in case it is a forwarder block. */ | |
635 | if (! single_pred_p (e_default->dest)) | |
636 | info->final_bb = e_default->dest; | |
637 | else if (single_succ_p (e_default->dest) | |
638 | && ! single_pred_p (single_succ (e_default->dest))) | |
639 | info->final_bb = single_succ (e_default->dest); | |
640 | /* Require that all switch destinations are either that common | |
641 | FINAL_BB or a forwarder to it. */ | |
886cd84f SB |
642 | if (info->final_bb) |
643 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
644 | { | |
645 | if (e->dest == info->final_bb) | |
646 | continue; | |
647 | ||
648 | if (single_pred_p (e->dest) | |
649 | && single_succ_p (e->dest) | |
650 | && single_succ (e->dest) == info->final_bb) | |
651 | continue; | |
652 | ||
653 | info->final_bb = NULL; | |
654 | break; | |
655 | } | |
656 | ||
657 | /* Get upper and lower bounds of case values, and the covered range. */ | |
658 | min_case = gimple_switch_label (swtch, 1); | |
726a989a | 659 | max_case = gimple_switch_label (swtch, branch_num - 1); |
886cd84f SB |
660 | |
661 | info->range_min = CASE_LOW (min_case); | |
b6e99746 | 662 | if (CASE_HIGH (max_case) != NULL_TREE) |
886cd84f | 663 | info->range_max = CASE_HIGH (max_case); |
b6e99746 | 664 | else |
886cd84f SB |
665 | info->range_max = CASE_LOW (max_case); |
666 | ||
667 | info->range_size = | |
668 | int_const_binop (MINUS_EXPR, info->range_max, info->range_min); | |
b6e99746 | 669 | |
886cd84f SB |
670 | /* Get a count of the number of case labels. Single-valued case labels |
671 | simply count as one, but a case range counts double, since it may | |
672 | require two compares if it gets lowered as a branching tree. */ | |
673 | count = 0; | |
674 | for (i = 1; i < branch_num; i++) | |
675 | { | |
676 | tree elt = gimple_switch_label (swtch, i); | |
677 | count++; | |
678 | if (CASE_HIGH (elt) | |
679 | && ! tree_int_cst_equal (CASE_LOW (elt), CASE_HIGH (elt))) | |
680 | count++; | |
681 | } | |
682 | info->count = count; | |
683 | ||
684 | /* Get the number of unique non-default targets out of the GIMPLE_SWITCH | |
685 | block. Assume a CFG cleanup would have already removed degenerate | |
686 | switch statements, this allows us to just use EDGE_COUNT. */ | |
687 | info->uniq = EDGE_COUNT (gimple_bb (swtch)->succs) - 1; | |
688 | } | |
b6e99746 | 689 | |
886cd84f SB |
690 | /* Checks whether the range given by individual case statements of the SWTCH |
691 | switch statement isn't too big and whether the number of branches actually | |
692 | satisfies the size of the new array. */ | |
b6e99746 | 693 | |
886cd84f SB |
694 | static bool |
695 | check_range (struct switch_conv_info *info) | |
696 | { | |
fade902a | 697 | gcc_assert (info->range_size); |
cc269bb6 | 698 | if (!tree_fits_uhwi_p (info->range_size)) |
b6e99746 | 699 | { |
fade902a | 700 | info->reason = "index range way too large or otherwise unusable"; |
b6e99746 MJ |
701 | return false; |
702 | } | |
703 | ||
7d362f6c | 704 | if (tree_to_uhwi (info->range_size) |
886cd84f | 705 | > ((unsigned) info->count * SWITCH_CONVERSION_BRANCH_RATIO)) |
b6e99746 | 706 | { |
fade902a | 707 | info->reason = "the maximum range-branch ratio exceeded"; |
b6e99746 MJ |
708 | return false; |
709 | } | |
710 | ||
711 | return true; | |
712 | } | |
713 | ||
886cd84f | 714 | /* Checks whether all but the FINAL_BB basic blocks are empty. */ |
b6e99746 MJ |
715 | |
716 | static bool | |
886cd84f | 717 | check_all_empty_except_final (struct switch_conv_info *info) |
b6e99746 | 718 | { |
b6e99746 | 719 | edge e; |
886cd84f | 720 | edge_iterator ei; |
b6e99746 | 721 | |
886cd84f | 722 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) |
b6e99746 | 723 | { |
886cd84f SB |
724 | if (e->dest == info->final_bb) |
725 | continue; | |
b6e99746 | 726 | |
886cd84f | 727 | if (!empty_block_p (e->dest)) |
b6e99746 | 728 | { |
fade902a | 729 | info->reason = "bad case - a non-final BB not empty"; |
b6e99746 MJ |
730 | return false; |
731 | } | |
b6e99746 MJ |
732 | } |
733 | ||
734 | return true; | |
735 | } | |
736 | ||
737 | /* This function checks whether all required values in phi nodes in final_bb | |
738 | are constants. Required values are those that correspond to a basic block | |
739 | which is a part of the examined switch statement. It returns true if the | |
740 | phi nodes are OK, otherwise false. */ | |
741 | ||
742 | static bool | |
fade902a | 743 | check_final_bb (struct switch_conv_info *info) |
b6e99746 | 744 | { |
538dd0b7 | 745 | gphi_iterator gsi; |
b6e99746 | 746 | |
fade902a SB |
747 | info->phi_count = 0; |
748 | for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
b6e99746 | 749 | { |
538dd0b7 | 750 | gphi *phi = gsi.phi (); |
726a989a | 751 | unsigned int i; |
b6e99746 | 752 | |
fade902a | 753 | info->phi_count++; |
b6e99746 | 754 | |
726a989a | 755 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
b6e99746 | 756 | { |
726a989a | 757 | basic_block bb = gimple_phi_arg_edge (phi, i)->src; |
b6e99746 | 758 | |
fade902a SB |
759 | if (bb == info->switch_bb |
760 | || (single_pred_p (bb) && single_pred (bb) == info->switch_bb)) | |
b6e99746 | 761 | { |
f6e6e990 JJ |
762 | tree reloc, val; |
763 | ||
764 | val = gimple_phi_arg_def (phi, i); | |
765 | if (!is_gimple_ip_invariant (val)) | |
766 | { | |
fade902a | 767 | info->reason = "non-invariant value from a case"; |
f6e6e990 JJ |
768 | return false; /* Non-invariant argument. */ |
769 | } | |
770 | reloc = initializer_constant_valid_p (val, TREE_TYPE (val)); | |
771 | if ((flag_pic && reloc != null_pointer_node) | |
772 | || (!flag_pic && reloc == NULL_TREE)) | |
773 | { | |
774 | if (reloc) | |
fade902a SB |
775 | info->reason |
776 | = "value from a case would need runtime relocations"; | |
f6e6e990 | 777 | else |
fade902a SB |
778 | info->reason |
779 | = "value from a case is not a valid initializer"; | |
f6e6e990 JJ |
780 | return false; |
781 | } | |
b6e99746 MJ |
782 | } |
783 | } | |
784 | } | |
785 | ||
786 | return true; | |
787 | } | |
788 | ||
789 | /* The following function allocates default_values, target_{in,out}_names and | |
790 | constructors arrays. The last one is also populated with pointers to | |
791 | vectors that will become constructors of new arrays. */ | |
792 | ||
793 | static void | |
fade902a | 794 | create_temp_arrays (struct switch_conv_info *info) |
b6e99746 MJ |
795 | { |
796 | int i; | |
797 | ||
fade902a | 798 | info->default_values = XCNEWVEC (tree, info->phi_count * 3); |
9771b263 DN |
799 | /* ??? Macros do not support multi argument templates in their |
800 | argument list. We create a typedef to work around that problem. */ | |
801 | typedef vec<constructor_elt, va_gc> *vec_constructor_elt_gc; | |
802 | info->constructors = XCNEWVEC (vec_constructor_elt_gc, info->phi_count); | |
fade902a SB |
803 | info->target_inbound_names = info->default_values + info->phi_count; |
804 | info->target_outbound_names = info->target_inbound_names + info->phi_count; | |
805 | for (i = 0; i < info->phi_count; i++) | |
ae7e9ddd | 806 | vec_alloc (info->constructors[i], tree_to_uhwi (info->range_size) + 1); |
b6e99746 MJ |
807 | } |
808 | ||
809 | /* Free the arrays created by create_temp_arrays(). The vectors that are | |
810 | created by that function are not freed here, however, because they have | |
811 | already become constructors and must be preserved. */ | |
812 | ||
813 | static void | |
fade902a | 814 | free_temp_arrays (struct switch_conv_info *info) |
b6e99746 | 815 | { |
fade902a SB |
816 | XDELETEVEC (info->constructors); |
817 | XDELETEVEC (info->default_values); | |
b6e99746 MJ |
818 | } |
819 | ||
820 | /* Populate the array of default values in the order of phi nodes. | |
821 | DEFAULT_CASE is the CASE_LABEL_EXPR for the default switch branch. */ | |
822 | ||
823 | static void | |
fade902a | 824 | gather_default_values (tree default_case, struct switch_conv_info *info) |
b6e99746 | 825 | { |
538dd0b7 | 826 | gphi_iterator gsi; |
b6e99746 MJ |
827 | basic_block bb = label_to_block (CASE_LABEL (default_case)); |
828 | edge e; | |
726a989a | 829 | int i = 0; |
b6e99746 MJ |
830 | |
831 | gcc_assert (CASE_LOW (default_case) == NULL_TREE); | |
832 | ||
fade902a SB |
833 | if (bb == info->final_bb) |
834 | e = find_edge (info->switch_bb, bb); | |
b6e99746 MJ |
835 | else |
836 | e = single_succ_edge (bb); | |
837 | ||
fade902a | 838 | for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
b6e99746 | 839 | { |
538dd0b7 | 840 | gphi *phi = gsi.phi (); |
b6e99746 MJ |
841 | tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
842 | gcc_assert (val); | |
fade902a | 843 | info->default_values[i++] = val; |
b6e99746 MJ |
844 | } |
845 | } | |
846 | ||
847 | /* The following function populates the vectors in the constructors array with | |
848 | future contents of the static arrays. The vectors are populated in the | |
849 | order of phi nodes. SWTCH is the switch statement being converted. */ | |
850 | ||
851 | static void | |
538dd0b7 | 852 | build_constructors (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 | 853 | { |
726a989a | 854 | unsigned i, branch_num = gimple_switch_num_labels (swtch); |
fade902a | 855 | tree pos = info->range_min; |
b6e99746 | 856 | |
726a989a | 857 | for (i = 1; i < branch_num; i++) |
b6e99746 | 858 | { |
726a989a | 859 | tree cs = gimple_switch_label (swtch, i); |
b6e99746 MJ |
860 | basic_block bb = label_to_block (CASE_LABEL (cs)); |
861 | edge e; | |
726a989a | 862 | tree high; |
538dd0b7 | 863 | gphi_iterator gsi; |
b6e99746 MJ |
864 | int j; |
865 | ||
fade902a SB |
866 | if (bb == info->final_bb) |
867 | e = find_edge (info->switch_bb, bb); | |
b6e99746 MJ |
868 | else |
869 | e = single_succ_edge (bb); | |
870 | gcc_assert (e); | |
871 | ||
872 | while (tree_int_cst_lt (pos, CASE_LOW (cs))) | |
873 | { | |
874 | int k; | |
fade902a | 875 | for (k = 0; k < info->phi_count; k++) |
b6e99746 | 876 | { |
f32682ca | 877 | constructor_elt elt; |
b6e99746 | 878 | |
f32682ca | 879 | elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); |
d1f98542 RB |
880 | elt.value |
881 | = unshare_expr_without_location (info->default_values[k]); | |
9771b263 | 882 | info->constructors[k]->quick_push (elt); |
b6e99746 MJ |
883 | } |
884 | ||
807e902e KZ |
885 | pos = int_const_binop (PLUS_EXPR, pos, |
886 | build_int_cst (TREE_TYPE (pos), 1)); | |
b6e99746 | 887 | } |
b1ae1681 | 888 | gcc_assert (tree_int_cst_equal (pos, CASE_LOW (cs))); |
b6e99746 MJ |
889 | |
890 | j = 0; | |
891 | if (CASE_HIGH (cs)) | |
892 | high = CASE_HIGH (cs); | |
893 | else | |
b1ae1681 | 894 | high = CASE_LOW (cs); |
fade902a | 895 | for (gsi = gsi_start_phis (info->final_bb); |
726a989a | 896 | !gsi_end_p (gsi); gsi_next (&gsi)) |
b6e99746 | 897 | { |
538dd0b7 | 898 | gphi *phi = gsi.phi (); |
b6e99746 | 899 | tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
7f2a9982 | 900 | tree low = CASE_LOW (cs); |
b6e99746 MJ |
901 | pos = CASE_LOW (cs); |
902 | ||
b8698a0f | 903 | do |
b6e99746 | 904 | { |
f32682ca | 905 | constructor_elt elt; |
b6e99746 | 906 | |
f32682ca | 907 | elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); |
d1f98542 | 908 | elt.value = unshare_expr_without_location (val); |
9771b263 | 909 | info->constructors[j]->quick_push (elt); |
b6e99746 | 910 | |
807e902e KZ |
911 | pos = int_const_binop (PLUS_EXPR, pos, |
912 | build_int_cst (TREE_TYPE (pos), 1)); | |
7156c8ab MJ |
913 | } while (!tree_int_cst_lt (high, pos) |
914 | && tree_int_cst_lt (low, pos)); | |
b6e99746 MJ |
915 | j++; |
916 | } | |
917 | } | |
918 | } | |
919 | ||
7156c8ab MJ |
920 | /* If all values in the constructor vector are the same, return the value. |
921 | Otherwise return NULL_TREE. Not supposed to be called for empty | |
922 | vectors. */ | |
923 | ||
924 | static tree | |
9771b263 | 925 | constructor_contains_same_values_p (vec<constructor_elt, va_gc> *vec) |
7156c8ab | 926 | { |
8e97bc2b | 927 | unsigned int i; |
7156c8ab | 928 | tree prev = NULL_TREE; |
8e97bc2b | 929 | constructor_elt *elt; |
7156c8ab | 930 | |
9771b263 | 931 | FOR_EACH_VEC_SAFE_ELT (vec, i, elt) |
7156c8ab | 932 | { |
7156c8ab MJ |
933 | if (!prev) |
934 | prev = elt->value; | |
935 | else if (!operand_equal_p (elt->value, prev, OEP_ONLY_CONST)) | |
936 | return NULL_TREE; | |
937 | } | |
938 | return prev; | |
939 | } | |
940 | ||
8e97bc2b JJ |
941 | /* Return type which should be used for array elements, either TYPE, |
942 | or for integral type some smaller integral type that can still hold | |
943 | all the constants. */ | |
944 | ||
945 | static tree | |
538dd0b7 | 946 | array_value_type (gswitch *swtch, tree type, int num, |
fade902a | 947 | struct switch_conv_info *info) |
8e97bc2b | 948 | { |
9771b263 | 949 | unsigned int i, len = vec_safe_length (info->constructors[num]); |
8e97bc2b | 950 | constructor_elt *elt; |
ef4bddc2 | 951 | machine_mode mode; |
8e97bc2b JJ |
952 | int sign = 0; |
953 | tree smaller_type; | |
954 | ||
955 | if (!INTEGRAL_TYPE_P (type)) | |
956 | return type; | |
957 | ||
958 | mode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (TYPE_MODE (type))); | |
959 | if (GET_MODE_SIZE (TYPE_MODE (type)) <= GET_MODE_SIZE (mode)) | |
960 | return type; | |
961 | ||
962 | if (len < (optimize_bb_for_size_p (gimple_bb (swtch)) ? 2 : 32)) | |
963 | return type; | |
964 | ||
9771b263 | 965 | FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
8e97bc2b | 966 | { |
807e902e | 967 | wide_int cst; |
8e97bc2b JJ |
968 | |
969 | if (TREE_CODE (elt->value) != INTEGER_CST) | |
970 | return type; | |
971 | ||
807e902e | 972 | cst = elt->value; |
8e97bc2b JJ |
973 | while (1) |
974 | { | |
975 | unsigned int prec = GET_MODE_BITSIZE (mode); | |
976 | if (prec > HOST_BITS_PER_WIDE_INT) | |
977 | return type; | |
978 | ||
807e902e | 979 | if (sign >= 0 && cst == wi::zext (cst, prec)) |
8e97bc2b | 980 | { |
807e902e | 981 | if (sign == 0 && cst == wi::sext (cst, prec)) |
8e97bc2b JJ |
982 | break; |
983 | sign = 1; | |
984 | break; | |
985 | } | |
807e902e | 986 | if (sign <= 0 && cst == wi::sext (cst, prec)) |
8e97bc2b JJ |
987 | { |
988 | sign = -1; | |
989 | break; | |
990 | } | |
991 | ||
992 | if (sign == 1) | |
993 | sign = 0; | |
994 | ||
995 | mode = GET_MODE_WIDER_MODE (mode); | |
996 | if (mode == VOIDmode | |
997 | || GET_MODE_SIZE (mode) >= GET_MODE_SIZE (TYPE_MODE (type))) | |
998 | return type; | |
999 | } | |
1000 | } | |
1001 | ||
1002 | if (sign == 0) | |
1003 | sign = TYPE_UNSIGNED (type) ? 1 : -1; | |
1004 | smaller_type = lang_hooks.types.type_for_mode (mode, sign >= 0); | |
1005 | if (GET_MODE_SIZE (TYPE_MODE (type)) | |
1006 | <= GET_MODE_SIZE (TYPE_MODE (smaller_type))) | |
1007 | return type; | |
1008 | ||
1009 | return smaller_type; | |
1010 | } | |
1011 | ||
b6e99746 MJ |
1012 | /* Create an appropriate array type and declaration and assemble a static array |
1013 | variable. Also create a load statement that initializes the variable in | |
1014 | question with a value from the static array. SWTCH is the switch statement | |
1015 | being converted, NUM is the index to arrays of constructors, default values | |
1016 | and target SSA names for this particular array. ARR_INDEX_TYPE is the type | |
1017 | of the index of the new array, PHI is the phi node of the final BB that | |
1018 | corresponds to the value that will be loaded from the created array. TIDX | |
7156c8ab MJ |
1019 | is an ssa name of a temporary variable holding the index for loads from the |
1020 | new array. */ | |
b6e99746 MJ |
1021 | |
1022 | static void | |
538dd0b7 DM |
1023 | build_one_array (gswitch *swtch, int num, tree arr_index_type, |
1024 | gphi *phi, tree tidx, struct switch_conv_info *info) | |
b6e99746 | 1025 | { |
7156c8ab | 1026 | tree name, cst; |
355fe088 | 1027 | gimple *load; |
7156c8ab | 1028 | gimple_stmt_iterator gsi = gsi_for_stmt (swtch); |
c2255bc4 | 1029 | location_t loc = gimple_location (swtch); |
b6e99746 | 1030 | |
fade902a | 1031 | gcc_assert (info->default_values[num]); |
b6e99746 | 1032 | |
b731b390 | 1033 | name = copy_ssa_name (PHI_RESULT (phi)); |
fade902a | 1034 | info->target_inbound_names[num] = name; |
b6e99746 | 1035 | |
fade902a | 1036 | cst = constructor_contains_same_values_p (info->constructors[num]); |
7156c8ab MJ |
1037 | if (cst) |
1038 | load = gimple_build_assign (name, cst); | |
1039 | else | |
1040 | { | |
8e97bc2b | 1041 | tree array_type, ctor, decl, value_type, fetch, default_type; |
7156c8ab | 1042 | |
fade902a SB |
1043 | default_type = TREE_TYPE (info->default_values[num]); |
1044 | value_type = array_value_type (swtch, default_type, num, info); | |
7156c8ab | 1045 | array_type = build_array_type (value_type, arr_index_type); |
8e97bc2b JJ |
1046 | if (default_type != value_type) |
1047 | { | |
1048 | unsigned int i; | |
1049 | constructor_elt *elt; | |
1050 | ||
9771b263 | 1051 | FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
8e97bc2b JJ |
1052 | elt->value = fold_convert (value_type, elt->value); |
1053 | } | |
fade902a | 1054 | ctor = build_constructor (array_type, info->constructors[num]); |
7156c8ab | 1055 | TREE_CONSTANT (ctor) = true; |
5f7ae6b6 | 1056 | TREE_STATIC (ctor) = true; |
7156c8ab | 1057 | |
c2255bc4 | 1058 | decl = build_decl (loc, VAR_DECL, NULL_TREE, array_type); |
7156c8ab MJ |
1059 | TREE_STATIC (decl) = 1; |
1060 | DECL_INITIAL (decl) = ctor; | |
1061 | ||
1062 | DECL_NAME (decl) = create_tmp_var_name ("CSWTCH"); | |
1063 | DECL_ARTIFICIAL (decl) = 1; | |
f8d851c6 | 1064 | DECL_IGNORED_P (decl) = 1; |
7156c8ab | 1065 | TREE_CONSTANT (decl) = 1; |
2e3b4885 | 1066 | TREE_READONLY (decl) = 1; |
d7438551 | 1067 | DECL_IGNORED_P (decl) = 1; |
9041d2e6 | 1068 | varpool_node::finalize_decl (decl); |
7156c8ab MJ |
1069 | |
1070 | fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE, | |
1071 | NULL_TREE); | |
8e97bc2b JJ |
1072 | if (default_type != value_type) |
1073 | { | |
1074 | fetch = fold_convert (default_type, fetch); | |
1075 | fetch = force_gimple_operand_gsi (&gsi, fetch, true, NULL_TREE, | |
1076 | true, GSI_SAME_STMT); | |
1077 | } | |
7156c8ab MJ |
1078 | load = gimple_build_assign (name, fetch); |
1079 | } | |
b6e99746 | 1080 | |
726a989a | 1081 | gsi_insert_before (&gsi, load, GSI_SAME_STMT); |
7156c8ab | 1082 | update_stmt (load); |
fade902a | 1083 | info->arr_ref_last = load; |
b6e99746 MJ |
1084 | } |
1085 | ||
1086 | /* Builds and initializes static arrays initialized with values gathered from | |
1087 | the SWTCH switch statement. Also creates statements that load values from | |
1088 | them. */ | |
1089 | ||
1090 | static void | |
538dd0b7 | 1091 | build_arrays (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 MJ |
1092 | { |
1093 | tree arr_index_type; | |
83d5977e | 1094 | tree tidx, sub, utype; |
355fe088 | 1095 | gimple *stmt; |
726a989a | 1096 | gimple_stmt_iterator gsi; |
538dd0b7 | 1097 | gphi_iterator gpi; |
b6e99746 | 1098 | int i; |
db3927fb | 1099 | location_t loc = gimple_location (swtch); |
b6e99746 | 1100 | |
726a989a | 1101 | gsi = gsi_for_stmt (swtch); |
04e78aa9 | 1102 | |
edb9b69e | 1103 | /* Make sure we do not generate arithmetics in a subrange. */ |
fade902a | 1104 | utype = TREE_TYPE (info->index_expr); |
edb9b69e JJ |
1105 | if (TREE_TYPE (utype)) |
1106 | utype = lang_hooks.types.type_for_mode (TYPE_MODE (TREE_TYPE (utype)), 1); | |
1107 | else | |
1108 | utype = lang_hooks.types.type_for_mode (TYPE_MODE (utype), 1); | |
1109 | ||
fade902a | 1110 | arr_index_type = build_index_type (info->range_size); |
b731b390 | 1111 | tidx = make_ssa_name (utype); |
edb9b69e | 1112 | sub = fold_build2_loc (loc, MINUS_EXPR, utype, |
fade902a SB |
1113 | fold_convert_loc (loc, utype, info->index_expr), |
1114 | fold_convert_loc (loc, utype, info->range_min)); | |
fae1034e | 1115 | sub = force_gimple_operand_gsi (&gsi, sub, |
726a989a RB |
1116 | false, NULL, true, GSI_SAME_STMT); |
1117 | stmt = gimple_build_assign (tidx, sub); | |
b6e99746 | 1118 | |
726a989a | 1119 | gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); |
7156c8ab | 1120 | update_stmt (stmt); |
fade902a | 1121 | info->arr_ref_first = stmt; |
b6e99746 | 1122 | |
538dd0b7 DM |
1123 | for (gpi = gsi_start_phis (info->final_bb), i = 0; |
1124 | !gsi_end_p (gpi); gsi_next (&gpi), i++) | |
1125 | build_one_array (swtch, i, arr_index_type, gpi.phi (), tidx, info); | |
b6e99746 MJ |
1126 | } |
1127 | ||
1128 | /* Generates and appropriately inserts loads of default values at the position | |
1129 | given by BSI. Returns the last inserted statement. */ | |
1130 | ||
538dd0b7 | 1131 | static gassign * |
fade902a | 1132 | gen_def_assigns (gimple_stmt_iterator *gsi, struct switch_conv_info *info) |
b6e99746 MJ |
1133 | { |
1134 | int i; | |
538dd0b7 | 1135 | gassign *assign = NULL; |
b6e99746 | 1136 | |
fade902a | 1137 | for (i = 0; i < info->phi_count; i++) |
b6e99746 | 1138 | { |
b731b390 | 1139 | tree name = copy_ssa_name (info->target_inbound_names[i]); |
fade902a SB |
1140 | info->target_outbound_names[i] = name; |
1141 | assign = gimple_build_assign (name, info->default_values[i]); | |
726a989a | 1142 | gsi_insert_before (gsi, assign, GSI_SAME_STMT); |
7156c8ab | 1143 | update_stmt (assign); |
b6e99746 MJ |
1144 | } |
1145 | return assign; | |
1146 | } | |
1147 | ||
1148 | /* Deletes the unused bbs and edges that now contain the switch statement and | |
1149 | its empty branch bbs. BBD is the now dead BB containing the original switch | |
1150 | statement, FINAL is the last BB of the converted switch statement (in terms | |
1151 | of succession). */ | |
1152 | ||
1153 | static void | |
1154 | prune_bbs (basic_block bbd, basic_block final) | |
1155 | { | |
1156 | edge_iterator ei; | |
1157 | edge e; | |
1158 | ||
1159 | for (ei = ei_start (bbd->succs); (e = ei_safe_edge (ei)); ) | |
1160 | { | |
1161 | basic_block bb; | |
1162 | bb = e->dest; | |
1163 | remove_edge (e); | |
1164 | if (bb != final) | |
1165 | delete_basic_block (bb); | |
1166 | } | |
1167 | delete_basic_block (bbd); | |
1168 | } | |
1169 | ||
1170 | /* Add values to phi nodes in final_bb for the two new edges. E1F is the edge | |
1171 | from the basic block loading values from an array and E2F from the basic | |
1172 | block loading default values. BBF is the last switch basic block (see the | |
1173 | bbf description in the comment below). */ | |
1174 | ||
1175 | static void | |
fade902a SB |
1176 | fix_phi_nodes (edge e1f, edge e2f, basic_block bbf, |
1177 | struct switch_conv_info *info) | |
b6e99746 | 1178 | { |
538dd0b7 | 1179 | gphi_iterator gsi; |
b6e99746 MJ |
1180 | int i; |
1181 | ||
726a989a RB |
1182 | for (gsi = gsi_start_phis (bbf), i = 0; |
1183 | !gsi_end_p (gsi); gsi_next (&gsi), i++) | |
b6e99746 | 1184 | { |
538dd0b7 | 1185 | gphi *phi = gsi.phi (); |
9e227d60 DC |
1186 | add_phi_arg (phi, info->target_inbound_names[i], e1f, UNKNOWN_LOCATION); |
1187 | add_phi_arg (phi, info->target_outbound_names[i], e2f, UNKNOWN_LOCATION); | |
b6e99746 | 1188 | } |
b6e99746 MJ |
1189 | } |
1190 | ||
1191 | /* Creates a check whether the switch expression value actually falls into the | |
1192 | range given by all the cases. If it does not, the temporaries are loaded | |
1193 | with default values instead. SWTCH is the switch statement being converted. | |
1194 | ||
1195 | bb0 is the bb with the switch statement, however, we'll end it with a | |
1196 | condition instead. | |
1197 | ||
1198 | bb1 is the bb to be used when the range check went ok. It is derived from | |
1199 | the switch BB | |
1200 | ||
1201 | bb2 is the bb taken when the expression evaluated outside of the range | |
1202 | covered by the created arrays. It is populated by loads of default | |
1203 | values. | |
1204 | ||
1205 | bbF is a fall through for both bb1 and bb2 and contains exactly what | |
1206 | originally followed the switch statement. | |
1207 | ||
1208 | bbD contains the switch statement (in the end). It is unreachable but we | |
1209 | still need to strip off its edges. | |
1210 | */ | |
1211 | ||
1212 | static void | |
538dd0b7 | 1213 | gen_inbound_check (gswitch *swtch, struct switch_conv_info *info) |
b6e99746 | 1214 | { |
c2255bc4 AH |
1215 | tree label_decl1 = create_artificial_label (UNKNOWN_LOCATION); |
1216 | tree label_decl2 = create_artificial_label (UNKNOWN_LOCATION); | |
1217 | tree label_decl3 = create_artificial_label (UNKNOWN_LOCATION); | |
538dd0b7 | 1218 | glabel *label1, *label2, *label3; |
edb9b69e | 1219 | tree utype, tidx; |
b6e99746 MJ |
1220 | tree bound; |
1221 | ||
538dd0b7 | 1222 | gcond *cond_stmt; |
b6e99746 | 1223 | |
538dd0b7 | 1224 | gassign *last_assign; |
726a989a | 1225 | gimple_stmt_iterator gsi; |
b6e99746 MJ |
1226 | basic_block bb0, bb1, bb2, bbf, bbd; |
1227 | edge e01, e02, e21, e1d, e1f, e2f; | |
db3927fb | 1228 | location_t loc = gimple_location (swtch); |
b6e99746 | 1229 | |
fade902a | 1230 | gcc_assert (info->default_values); |
6ab1ab14 | 1231 | |
726a989a | 1232 | bb0 = gimple_bb (swtch); |
b6e99746 | 1233 | |
fade902a | 1234 | tidx = gimple_assign_lhs (info->arr_ref_first); |
edb9b69e | 1235 | utype = TREE_TYPE (tidx); |
145544ab | 1236 | |
b6e99746 | 1237 | /* (end of) block 0 */ |
fade902a | 1238 | gsi = gsi_for_stmt (info->arr_ref_first); |
edb9b69e | 1239 | gsi_next (&gsi); |
b6e99746 | 1240 | |
fade902a | 1241 | bound = fold_convert_loc (loc, utype, info->range_size); |
edb9b69e | 1242 | cond_stmt = gimple_build_cond (LE_EXPR, tidx, bound, NULL_TREE, NULL_TREE); |
726a989a | 1243 | gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT); |
7156c8ab | 1244 | update_stmt (cond_stmt); |
b6e99746 MJ |
1245 | |
1246 | /* block 2 */ | |
726a989a RB |
1247 | label2 = gimple_build_label (label_decl2); |
1248 | gsi_insert_before (&gsi, label2, GSI_SAME_STMT); | |
fade902a | 1249 | last_assign = gen_def_assigns (&gsi, info); |
b6e99746 MJ |
1250 | |
1251 | /* block 1 */ | |
726a989a RB |
1252 | label1 = gimple_build_label (label_decl1); |
1253 | gsi_insert_before (&gsi, label1, GSI_SAME_STMT); | |
b6e99746 MJ |
1254 | |
1255 | /* block F */ | |
fade902a | 1256 | gsi = gsi_start_bb (info->final_bb); |
726a989a RB |
1257 | label3 = gimple_build_label (label_decl3); |
1258 | gsi_insert_before (&gsi, label3, GSI_SAME_STMT); | |
b6e99746 MJ |
1259 | |
1260 | /* cfg fix */ | |
726a989a | 1261 | e02 = split_block (bb0, cond_stmt); |
b6e99746 MJ |
1262 | bb2 = e02->dest; |
1263 | ||
1264 | e21 = split_block (bb2, last_assign); | |
1265 | bb1 = e21->dest; | |
1266 | remove_edge (e21); | |
1267 | ||
fade902a | 1268 | e1d = split_block (bb1, info->arr_ref_last); |
b6e99746 MJ |
1269 | bbd = e1d->dest; |
1270 | remove_edge (e1d); | |
1271 | ||
1272 | /* flags and profiles of the edge for in-range values */ | |
1273 | e01 = make_edge (bb0, bb1, EDGE_TRUE_VALUE); | |
fade902a SB |
1274 | e01->probability = REG_BR_PROB_BASE - info->default_prob; |
1275 | e01->count = info->other_count; | |
b6e99746 MJ |
1276 | |
1277 | /* flags and profiles of the edge taking care of out-of-range values */ | |
1278 | e02->flags &= ~EDGE_FALLTHRU; | |
1279 | e02->flags |= EDGE_FALSE_VALUE; | |
fade902a SB |
1280 | e02->probability = info->default_prob; |
1281 | e02->count = info->default_count; | |
b6e99746 | 1282 | |
fade902a | 1283 | bbf = info->final_bb; |
b6e99746 MJ |
1284 | |
1285 | e1f = make_edge (bb1, bbf, EDGE_FALLTHRU); | |
1286 | e1f->probability = REG_BR_PROB_BASE; | |
fade902a | 1287 | e1f->count = info->other_count; |
b6e99746 MJ |
1288 | |
1289 | e2f = make_edge (bb2, bbf, EDGE_FALLTHRU); | |
1290 | e2f->probability = REG_BR_PROB_BASE; | |
fade902a | 1291 | e2f->count = info->default_count; |
b6e99746 MJ |
1292 | |
1293 | /* frequencies of the new BBs */ | |
1294 | bb1->frequency = EDGE_FREQUENCY (e01); | |
1295 | bb2->frequency = EDGE_FREQUENCY (e02); | |
1296 | bbf->frequency = EDGE_FREQUENCY (e1f) + EDGE_FREQUENCY (e2f); | |
1297 | ||
6ab1ab14 SB |
1298 | /* Tidy blocks that have become unreachable. */ |
1299 | prune_bbs (bbd, info->final_bb); | |
b6e99746 | 1300 | |
6ab1ab14 | 1301 | /* Fixup the PHI nodes in bbF. */ |
fade902a | 1302 | fix_phi_nodes (e1f, e2f, bbf, info); |
b6e99746 | 1303 | |
6ab1ab14 SB |
1304 | /* Fix the dominator tree, if it is available. */ |
1305 | if (dom_info_available_p (CDI_DOMINATORS)) | |
1306 | { | |
9771b263 | 1307 | vec<basic_block> bbs_to_fix_dom; |
6ab1ab14 SB |
1308 | |
1309 | set_immediate_dominator (CDI_DOMINATORS, bb1, bb0); | |
1310 | set_immediate_dominator (CDI_DOMINATORS, bb2, bb0); | |
531b10fc | 1311 | if (! get_immediate_dominator (CDI_DOMINATORS, bbf)) |
6ab1ab14 SB |
1312 | /* If bbD was the immediate dominator ... */ |
1313 | set_immediate_dominator (CDI_DOMINATORS, bbf, bb0); | |
1314 | ||
9771b263 DN |
1315 | bbs_to_fix_dom.create (4); |
1316 | bbs_to_fix_dom.quick_push (bb0); | |
1317 | bbs_to_fix_dom.quick_push (bb1); | |
1318 | bbs_to_fix_dom.quick_push (bb2); | |
1319 | bbs_to_fix_dom.quick_push (bbf); | |
6ab1ab14 SB |
1320 | |
1321 | iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
9771b263 | 1322 | bbs_to_fix_dom.release (); |
6ab1ab14 | 1323 | } |
b6e99746 MJ |
1324 | } |
1325 | ||
1326 | /* The following function is invoked on every switch statement (the current one | |
1327 | is given in SWTCH) and runs the individual phases of switch conversion on it | |
fade902a SB |
1328 | one after another until one fails or the conversion is completed. |
1329 | Returns NULL on success, or a pointer to a string with the reason why the | |
1330 | conversion failed. */ | |
b6e99746 | 1331 | |
fade902a | 1332 | static const char * |
538dd0b7 | 1333 | process_switch (gswitch *swtch) |
b6e99746 | 1334 | { |
fade902a | 1335 | struct switch_conv_info info; |
b6e99746 | 1336 | |
238065a7 SB |
1337 | /* Group case labels so that we get the right results from the heuristics |
1338 | that decide on the code generation approach for this switch. */ | |
1339 | group_case_labels_stmt (swtch); | |
1340 | ||
1341 | /* If this switch is now a degenerate case with only a default label, | |
1342 | there is nothing left for us to do. */ | |
1343 | if (gimple_switch_num_labels (swtch) < 2) | |
1344 | return "switch is a degenerate case"; | |
886cd84f SB |
1345 | |
1346 | collect_switch_conv_info (swtch, &info); | |
1347 | ||
1348 | /* No error markers should reach here (they should be filtered out | |
1349 | during gimplification). */ | |
1350 | gcc_checking_assert (TREE_TYPE (info.index_expr) != error_mark_node); | |
1351 | ||
531b10fc SB |
1352 | /* A switch on a constant should have been optimized in tree-cfg-cleanup. */ |
1353 | gcc_checking_assert (! TREE_CONSTANT (info.index_expr)); | |
886cd84f | 1354 | |
531b10fc | 1355 | if (info.uniq <= MAX_CASE_BIT_TESTS) |
886cd84f | 1356 | { |
531b10fc | 1357 | if (expand_switch_using_bit_tests_p (info.range_size, |
72798784 RB |
1358 | info.uniq, info.count, |
1359 | optimize_bb_for_speed_p | |
1360 | (gimple_bb (swtch)))) | |
531b10fc SB |
1361 | { |
1362 | if (dump_file) | |
1363 | fputs (" expanding as bit test is preferable\n", dump_file); | |
aa79a1e1 JJ |
1364 | emit_case_bit_tests (swtch, info.index_expr, info.range_min, |
1365 | info.range_size, info.range_max); | |
726338f4 | 1366 | loops_state_set (LOOPS_NEED_FIXUP); |
531b10fc SB |
1367 | return NULL; |
1368 | } | |
1369 | ||
1370 | if (info.uniq <= 2) | |
1371 | /* This will be expanded as a decision tree in stmt.c:expand_case. */ | |
1372 | return " expanding as jumps is preferable"; | |
886cd84f | 1373 | } |
b6e99746 | 1374 | |
531b10fc SB |
1375 | /* If there is no common successor, we cannot do the transformation. */ |
1376 | if (! info.final_bb) | |
1377 | return "no common successor to all case label target blocks found"; | |
1378 | ||
b6e99746 | 1379 | /* Check the case label values are within reasonable range: */ |
886cd84f | 1380 | if (!check_range (&info)) |
fade902a SB |
1381 | { |
1382 | gcc_assert (info.reason); | |
1383 | return info.reason; | |
1384 | } | |
b6e99746 MJ |
1385 | |
1386 | /* For all the cases, see whether they are empty, the assignments they | |
1387 | represent constant and so on... */ | |
886cd84f | 1388 | if (! check_all_empty_except_final (&info)) |
8e97bc2b | 1389 | { |
886cd84f SB |
1390 | gcc_assert (info.reason); |
1391 | return info.reason; | |
8e97bc2b | 1392 | } |
fade902a SB |
1393 | if (!check_final_bb (&info)) |
1394 | { | |
1395 | gcc_assert (info.reason); | |
1396 | return info.reason; | |
1397 | } | |
b6e99746 MJ |
1398 | |
1399 | /* At this point all checks have passed and we can proceed with the | |
1400 | transformation. */ | |
1401 | ||
fade902a | 1402 | create_temp_arrays (&info); |
fd8d363e | 1403 | gather_default_values (gimple_switch_default_label (swtch), &info); |
fade902a | 1404 | build_constructors (swtch, &info); |
b6e99746 | 1405 | |
fade902a SB |
1406 | build_arrays (swtch, &info); /* Build the static arrays and assignments. */ |
1407 | gen_inbound_check (swtch, &info); /* Build the bounds check. */ | |
b6e99746 MJ |
1408 | |
1409 | /* Cleanup: */ | |
fade902a SB |
1410 | free_temp_arrays (&info); |
1411 | return NULL; | |
b6e99746 MJ |
1412 | } |
1413 | ||
1414 | /* The main function of the pass scans statements for switches and invokes | |
1415 | process_switch on them. */ | |
1416 | ||
be55bfe6 TS |
1417 | namespace { |
1418 | ||
1419 | const pass_data pass_data_convert_switch = | |
1420 | { | |
1421 | GIMPLE_PASS, /* type */ | |
1422 | "switchconv", /* name */ | |
1423 | OPTGROUP_NONE, /* optinfo_flags */ | |
be55bfe6 TS |
1424 | TV_TREE_SWITCH_CONVERSION, /* tv_id */ |
1425 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1426 | 0, /* properties_provided */ | |
1427 | 0, /* properties_destroyed */ | |
1428 | 0, /* todo_flags_start */ | |
3bea341f | 1429 | TODO_update_ssa, /* todo_flags_finish */ |
be55bfe6 TS |
1430 | }; |
1431 | ||
1432 | class pass_convert_switch : public gimple_opt_pass | |
1433 | { | |
1434 | public: | |
1435 | pass_convert_switch (gcc::context *ctxt) | |
1436 | : gimple_opt_pass (pass_data_convert_switch, ctxt) | |
1437 | {} | |
1438 | ||
1439 | /* opt_pass methods: */ | |
1440 | virtual bool gate (function *) { return flag_tree_switch_conversion != 0; } | |
1441 | virtual unsigned int execute (function *); | |
1442 | ||
1443 | }; // class pass_convert_switch | |
1444 | ||
1445 | unsigned int | |
1446 | pass_convert_switch::execute (function *fun) | |
b6e99746 MJ |
1447 | { |
1448 | basic_block bb; | |
1449 | ||
be55bfe6 | 1450 | FOR_EACH_BB_FN (bb, fun) |
b6e99746 | 1451 | { |
fade902a | 1452 | const char *failure_reason; |
355fe088 | 1453 | gimple *stmt = last_stmt (bb); |
726a989a | 1454 | if (stmt && gimple_code (stmt) == GIMPLE_SWITCH) |
b6e99746 | 1455 | { |
b6e99746 MJ |
1456 | if (dump_file) |
1457 | { | |
726a989a RB |
1458 | expanded_location loc = expand_location (gimple_location (stmt)); |
1459 | ||
b6e99746 MJ |
1460 | fprintf (dump_file, "beginning to process the following " |
1461 | "SWITCH statement (%s:%d) : ------- \n", | |
1462 | loc.file, loc.line); | |
726a989a | 1463 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
edb30094 | 1464 | putc ('\n', dump_file); |
b6e99746 MJ |
1465 | } |
1466 | ||
538dd0b7 | 1467 | failure_reason = process_switch (as_a <gswitch *> (stmt)); |
fade902a | 1468 | if (! failure_reason) |
b6e99746 MJ |
1469 | { |
1470 | if (dump_file) | |
1471 | { | |
edb30094 UB |
1472 | fputs ("Switch converted\n", dump_file); |
1473 | fputs ("--------------------------------\n", dump_file); | |
b6e99746 | 1474 | } |
531b10fc SB |
1475 | |
1476 | /* Make no effort to update the post-dominator tree. It is actually not | |
1477 | that hard for the transformations we have performed, but it is not | |
1478 | supported by iterate_fix_dominators. */ | |
1479 | free_dominance_info (CDI_POST_DOMINATORS); | |
b6e99746 MJ |
1480 | } |
1481 | else | |
1482 | { | |
1483 | if (dump_file) | |
1484 | { | |
edb30094 | 1485 | fputs ("Bailing out - ", dump_file); |
fade902a SB |
1486 | fputs (failure_reason, dump_file); |
1487 | fputs ("\n--------------------------------\n", dump_file); | |
b6e99746 MJ |
1488 | } |
1489 | } | |
1490 | } | |
1491 | } | |
1492 | ||
1493 | return 0; | |
1494 | } | |
1495 | ||
27a4cd48 DM |
1496 | } // anon namespace |
1497 | ||
1498 | gimple_opt_pass * | |
1499 | make_pass_convert_switch (gcc::context *ctxt) | |
1500 | { | |
1501 | return new pass_convert_switch (ctxt); | |
1502 | } |