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78b7a675 | 1 | /* Lower GIMPLE_SWITCH expressions to something more efficient than |
2 | a jump table. | |
aad93da1 | 3 | Copyright (C) 2006-2017 Free Software Foundation, Inc. |
a347af29 | 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 | ||
78b7a675 | 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" | |
9ef16211 | 28 | #include "backend.h" |
7c29e30e | 29 | #include "insn-codes.h" |
30 | #include "rtl.h" | |
9ef16211 | 31 | #include "tree.h" |
32 | #include "gimple.h" | |
7c29e30e | 33 | #include "cfghooks.h" |
34 | #include "tree-pass.h" | |
9ef16211 | 35 | #include "ssa.h" |
7c29e30e | 36 | #include "optabs-tree.h" |
37 | #include "cgraph.h" | |
38 | #include "gimple-pretty-print.h" | |
78b7a675 | 39 | #include "params.h" |
b20a8bb4 | 40 | #include "fold-const.h" |
9ed99284 | 41 | #include "varasm.h" |
42 | #include "stor-layout.h" | |
94ea8568 | 43 | #include "cfganal.h" |
a8783bee | 44 | #include "gimplify.h" |
dcf1a1ec | 45 | #include "gimple-iterator.h" |
e795d6e1 | 46 | #include "gimplify-me.h" |
073c1fd5 | 47 | #include "tree-cfg.h" |
f6568ea4 | 48 | #include "cfgloop.h" |
b9ed1410 | 49 | |
50 | /* ??? For lang_hooks.types.type_for_mode, but is there a word_mode | |
51 | type in the GIMPLE type system that is language-independent? */ | |
78b7a675 | 52 | #include "langhooks.h" |
53 | ||
78b7a675 | 54 | \f |
55 | /* Maximum number of case bit tests. | |
56 | FIXME: This should be derived from PARAM_CASE_VALUES_THRESHOLD and | |
57 | targetm.case_values_threshold(), or be its own param. */ | |
58 | #define MAX_CASE_BIT_TESTS 3 | |
59 | ||
60 | /* Split the basic block at the statement pointed to by GSIP, and insert | |
61 | a branch to the target basic block of E_TRUE conditional on tree | |
62 | expression COND. | |
63 | ||
64 | It is assumed that there is already an edge from the to-be-split | |
65 | basic block to E_TRUE->dest block. This edge is removed, and the | |
66 | profile information on the edge is re-used for the new conditional | |
67 | jump. | |
68 | ||
69 | The CFG is updated. The dominator tree will not be valid after | |
70 | this transformation, but the immediate dominators are updated if | |
71 | UPDATE_DOMINATORS is true. | |
72 | ||
73 | Returns the newly created basic block. */ | |
74 | ||
75 | static basic_block | |
76 | hoist_edge_and_branch_if_true (gimple_stmt_iterator *gsip, | |
77 | tree cond, edge e_true, | |
78 | bool update_dominators) | |
79 | { | |
80 | tree tmp; | |
1a91d914 | 81 | gcond *cond_stmt; |
78b7a675 | 82 | edge e_false; |
83 | basic_block new_bb, split_bb = gsi_bb (*gsip); | |
84 | bool dominated_e_true = false; | |
85 | ||
86 | gcc_assert (e_true->src == split_bb); | |
87 | ||
88 | if (update_dominators | |
89 | && get_immediate_dominator (CDI_DOMINATORS, e_true->dest) == split_bb) | |
90 | dominated_e_true = true; | |
91 | ||
92 | tmp = force_gimple_operand_gsi (gsip, cond, /*simple=*/true, NULL, | |
93 | /*before=*/true, GSI_SAME_STMT); | |
94 | cond_stmt = gimple_build_cond_from_tree (tmp, NULL_TREE, NULL_TREE); | |
95 | gsi_insert_before (gsip, cond_stmt, GSI_SAME_STMT); | |
96 | ||
97 | e_false = split_block (split_bb, cond_stmt); | |
98 | new_bb = e_false->dest; | |
99 | redirect_edge_pred (e_true, split_bb); | |
100 | ||
101 | e_true->flags &= ~EDGE_FALLTHRU; | |
102 | e_true->flags |= EDGE_TRUE_VALUE; | |
103 | ||
104 | e_false->flags &= ~EDGE_FALLTHRU; | |
105 | e_false->flags |= EDGE_FALSE_VALUE; | |
106 | e_false->probability = REG_BR_PROB_BASE - e_true->probability; | |
107 | e_false->count = split_bb->count - e_true->count; | |
108 | new_bb->count = e_false->count; | |
109 | ||
110 | if (update_dominators) | |
111 | { | |
112 | if (dominated_e_true) | |
113 | set_immediate_dominator (CDI_DOMINATORS, e_true->dest, split_bb); | |
114 | set_immediate_dominator (CDI_DOMINATORS, e_false->dest, split_bb); | |
115 | } | |
116 | ||
117 | return new_bb; | |
118 | } | |
119 | ||
120 | ||
78b7a675 | 121 | /* Return true if a switch should be expanded as a bit test. |
122 | RANGE is the difference between highest and lowest case. | |
123 | UNIQ is number of unique case node targets, not counting the default case. | |
124 | COUNT is the number of comparisons needed, not counting the default case. */ | |
125 | ||
126 | static bool | |
127 | expand_switch_using_bit_tests_p (tree range, | |
128 | unsigned int uniq, | |
637a765f | 129 | unsigned int count, bool speed_p) |
78b7a675 | 130 | { |
131 | return (((uniq == 1 && count >= 3) | |
132 | || (uniq == 2 && count >= 5) | |
133 | || (uniq == 3 && count >= 6)) | |
637a765f | 134 | && lshift_cheap_p (speed_p) |
78b7a675 | 135 | && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0 |
136 | && compare_tree_int (range, 0) > 0); | |
137 | } | |
138 | \f | |
139 | /* Implement switch statements with bit tests | |
140 | ||
141 | A GIMPLE switch statement can be expanded to a short sequence of bit-wise | |
142 | comparisons. "switch(x)" is converted into "if ((1 << (x-MINVAL)) & CST)" | |
143 | where CST and MINVAL are integer constants. This is better than a series | |
144 | of compare-and-banch insns in some cases, e.g. we can implement: | |
145 | ||
146 | if ((x==4) || (x==6) || (x==9) || (x==11)) | |
147 | ||
148 | as a single bit test: | |
149 | ||
150 | if ((1<<x) & ((1<<4)|(1<<6)|(1<<9)|(1<<11))) | |
151 | ||
152 | This transformation is only applied if the number of case targets is small, | |
d8ab4f2a | 153 | if CST constains at least 3 bits, and "1 << x" is cheap. The bit tests are |
78b7a675 | 154 | performed in "word_mode". |
155 | ||
156 | The following example shows the code the transformation generates: | |
157 | ||
158 | int bar(int x) | |
159 | { | |
160 | switch (x) | |
161 | { | |
162 | case '0': case '1': case '2': case '3': case '4': | |
163 | case '5': case '6': case '7': case '8': case '9': | |
164 | case 'A': case 'B': case 'C': case 'D': case 'E': | |
165 | case 'F': | |
166 | return 1; | |
167 | } | |
168 | return 0; | |
169 | } | |
170 | ||
171 | ==> | |
172 | ||
173 | bar (int x) | |
174 | { | |
175 | tmp1 = x - 48; | |
176 | if (tmp1 > (70 - 48)) goto L2; | |
177 | tmp2 = 1 << tmp1; | |
178 | tmp3 = 0b11111100000001111111111; | |
179 | if ((tmp2 & tmp3) != 0) goto L1 ; else goto L2; | |
180 | L1: | |
181 | return 1; | |
182 | L2: | |
183 | return 0; | |
184 | } | |
185 | ||
186 | TODO: There are still some improvements to this transformation that could | |
187 | be implemented: | |
188 | ||
189 | * A narrower mode than word_mode could be used if that is cheaper, e.g. | |
190 | for x86_64 where a narrower-mode shift may result in smaller code. | |
191 | ||
192 | * The compounded constant could be shifted rather than the one. The | |
193 | test would be either on the sign bit or on the least significant bit, | |
194 | depending on the direction of the shift. On some machines, the test | |
195 | for the branch would be free if the bit to test is already set by the | |
196 | shift operation. | |
197 | ||
198 | This transformation was contributed by Roger Sayle, see this e-mail: | |
199 | http://gcc.gnu.org/ml/gcc-patches/2003-01/msg01950.html | |
200 | */ | |
201 | ||
202 | /* A case_bit_test represents a set of case nodes that may be | |
203 | selected from using a bit-wise comparison. HI and LO hold | |
204 | the integer to be tested against, TARGET_EDGE contains the | |
205 | edge to the basic block to jump to upon success and BITS | |
206 | counts the number of case nodes handled by this test, | |
207 | typically the number of bits set in HI:LO. The LABEL field | |
208 | is used to quickly identify all cases in this set without | |
209 | looking at label_to_block for every case label. */ | |
210 | ||
211 | struct case_bit_test | |
212 | { | |
bcf8a30c | 213 | wide_int mask; |
78b7a675 | 214 | edge target_edge; |
215 | tree label; | |
216 | int bits; | |
217 | }; | |
218 | ||
219 | /* Comparison function for qsort to order bit tests by decreasing | |
220 | probability of execution. Our best guess comes from a measured | |
221 | profile. If the profile counts are equal, break even on the | |
222 | number of case nodes, i.e. the node with the most cases gets | |
223 | tested first. | |
224 | ||
225 | TODO: Actually this currently runs before a profile is available. | |
226 | Therefore the case-as-bit-tests transformation should be done | |
227 | later in the pass pipeline, or something along the lines of | |
228 | "Efficient and effective branch reordering using profile data" | |
229 | (Yang et. al., 2002) should be implemented (although, how good | |
230 | is a paper is called "Efficient and effective ..." when the | |
231 | latter is implied by the former, but oh well...). */ | |
232 | ||
233 | static int | |
234 | case_bit_test_cmp (const void *p1, const void *p2) | |
235 | { | |
236 | const struct case_bit_test *const d1 = (const struct case_bit_test *) p1; | |
237 | const struct case_bit_test *const d2 = (const struct case_bit_test *) p2; | |
238 | ||
db9cef39 | 239 | if (d2->target_edge->count < d1->target_edge->count) |
240 | return -1; | |
241 | if (d2->target_edge->count > d1->target_edge->count) | |
242 | return 1; | |
78b7a675 | 243 | if (d2->bits != d1->bits) |
244 | return d2->bits - d1->bits; | |
245 | ||
246 | /* Stabilize the sort. */ | |
247 | return LABEL_DECL_UID (d2->label) - LABEL_DECL_UID (d1->label); | |
248 | } | |
249 | ||
250 | /* Expand a switch statement by a short sequence of bit-wise | |
251 | comparisons. "switch(x)" is effectively converted into | |
252 | "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are | |
253 | integer constants. | |
254 | ||
255 | INDEX_EXPR is the value being switched on. | |
256 | ||
257 | MINVAL is the lowest case value of in the case nodes, | |
258 | and RANGE is highest value minus MINVAL. MINVAL and RANGE | |
259 | are not guaranteed to be of the same type as INDEX_EXPR | |
260 | (the gimplifier doesn't change the type of case label values, | |
261 | and MINVAL and RANGE are derived from those values). | |
bcf8a30c | 262 | MAXVAL is MINVAL + RANGE. |
78b7a675 | 263 | |
264 | There *MUST* be MAX_CASE_BIT_TESTS or less unique case | |
265 | node targets. */ | |
266 | ||
267 | static void | |
1a91d914 | 268 | emit_case_bit_tests (gswitch *swtch, tree index_expr, |
bcf8a30c | 269 | tree minval, tree range, tree maxval) |
78b7a675 | 270 | { |
271 | struct case_bit_test test[MAX_CASE_BIT_TESTS]; | |
272 | unsigned int i, j, k; | |
273 | unsigned int count; | |
274 | ||
275 | basic_block switch_bb = gimple_bb (swtch); | |
276 | basic_block default_bb, new_default_bb, new_bb; | |
277 | edge default_edge; | |
278 | bool update_dom = dom_info_available_p (CDI_DOMINATORS); | |
279 | ||
1e094109 | 280 | vec<basic_block> bbs_to_fix_dom = vNULL; |
78b7a675 | 281 | |
282 | tree index_type = TREE_TYPE (index_expr); | |
283 | tree unsigned_index_type = unsigned_type_for (index_type); | |
284 | unsigned int branch_num = gimple_switch_num_labels (swtch); | |
285 | ||
286 | gimple_stmt_iterator gsi; | |
1a91d914 | 287 | gassign *shift_stmt; |
78b7a675 | 288 | |
289 | tree idx, tmp, csui; | |
290 | tree word_type_node = lang_hooks.types.type_for_mode (word_mode, 1); | |
291 | tree word_mode_zero = fold_convert (word_type_node, integer_zero_node); | |
292 | tree word_mode_one = fold_convert (word_type_node, integer_one_node); | |
bcf8a30c | 293 | int prec = TYPE_PRECISION (word_type_node); |
294 | wide_int wone = wi::one (prec); | |
78b7a675 | 295 | |
296 | memset (&test, 0, sizeof (test)); | |
297 | ||
298 | /* Get the edge for the default case. */ | |
49a70175 | 299 | tmp = gimple_switch_default_label (swtch); |
78b7a675 | 300 | default_bb = label_to_block (CASE_LABEL (tmp)); |
301 | default_edge = find_edge (switch_bb, default_bb); | |
302 | ||
303 | /* Go through all case labels, and collect the case labels, profile | |
304 | counts, and other information we need to build the branch tests. */ | |
305 | count = 0; | |
306 | for (i = 1; i < branch_num; i++) | |
307 | { | |
308 | unsigned int lo, hi; | |
309 | tree cs = gimple_switch_label (swtch, i); | |
310 | tree label = CASE_LABEL (cs); | |
3a7ac8c6 | 311 | edge e = find_edge (switch_bb, label_to_block (label)); |
78b7a675 | 312 | for (k = 0; k < count; k++) |
3a7ac8c6 | 313 | if (e == test[k].target_edge) |
78b7a675 | 314 | break; |
315 | ||
316 | if (k == count) | |
317 | { | |
78b7a675 | 318 | gcc_checking_assert (count < MAX_CASE_BIT_TESTS); |
bcf8a30c | 319 | test[k].mask = wi::zero (prec); |
78b7a675 | 320 | test[k].target_edge = e; |
321 | test[k].label = label; | |
322 | test[k].bits = 1; | |
323 | count++; | |
324 | } | |
325 | else | |
326 | test[k].bits++; | |
327 | ||
e913b5cd | 328 | lo = tree_to_uhwi (int_const_binop (MINUS_EXPR, |
329 | CASE_LOW (cs), minval)); | |
78b7a675 | 330 | if (CASE_HIGH (cs) == NULL_TREE) |
331 | hi = lo; | |
332 | else | |
08f817b3 | 333 | hi = tree_to_uhwi (int_const_binop (MINUS_EXPR, |
e913b5cd | 334 | CASE_HIGH (cs), minval)); |
78b7a675 | 335 | |
336 | for (j = lo; j <= hi; j++) | |
bcf8a30c | 337 | test[k].mask |= wi::lshift (wone, j); |
78b7a675 | 338 | } |
339 | ||
9af5ce0c | 340 | qsort (test, count, sizeof (*test), case_bit_test_cmp); |
78b7a675 | 341 | |
bcf8a30c | 342 | /* If all values are in the 0 .. BITS_PER_WORD-1 range, we can get rid of |
343 | the minval subtractions, but it might make the mask constants more | |
344 | expensive. So, compare the costs. */ | |
345 | if (compare_tree_int (minval, 0) > 0 | |
346 | && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0) | |
347 | { | |
348 | int cost_diff; | |
349 | HOST_WIDE_INT m = tree_to_uhwi (minval); | |
350 | rtx reg = gen_raw_REG (word_mode, 10000); | |
351 | bool speed_p = optimize_bb_for_speed_p (gimple_bb (swtch)); | |
352 | cost_diff = set_rtx_cost (gen_rtx_PLUS (word_mode, reg, | |
353 | GEN_INT (-m)), speed_p); | |
354 | for (i = 0; i < count; i++) | |
355 | { | |
356 | rtx r = immed_wide_int_const (test[i].mask, word_mode); | |
5ae4887d | 357 | cost_diff += set_src_cost (gen_rtx_AND (word_mode, reg, r), |
358 | word_mode, speed_p); | |
bcf8a30c | 359 | r = immed_wide_int_const (wi::lshift (test[i].mask, m), word_mode); |
5ae4887d | 360 | cost_diff -= set_src_cost (gen_rtx_AND (word_mode, reg, r), |
361 | word_mode, speed_p); | |
bcf8a30c | 362 | } |
363 | if (cost_diff > 0) | |
364 | { | |
365 | for (i = 0; i < count; i++) | |
366 | test[i].mask = wi::lshift (test[i].mask, m); | |
367 | minval = build_zero_cst (TREE_TYPE (minval)); | |
368 | range = maxval; | |
369 | } | |
370 | } | |
371 | ||
78b7a675 | 372 | /* We generate two jumps to the default case label. |
373 | Split the default edge, so that we don't have to do any PHI node | |
374 | updating. */ | |
375 | new_default_bb = split_edge (default_edge); | |
376 | ||
377 | if (update_dom) | |
378 | { | |
f1f41a6c | 379 | bbs_to_fix_dom.create (10); |
380 | bbs_to_fix_dom.quick_push (switch_bb); | |
381 | bbs_to_fix_dom.quick_push (default_bb); | |
382 | bbs_to_fix_dom.quick_push (new_default_bb); | |
78b7a675 | 383 | } |
384 | ||
385 | /* Now build the test-and-branch code. */ | |
386 | ||
387 | gsi = gsi_last_bb (switch_bb); | |
388 | ||
9e394672 | 389 | /* idx = (unsigned)x - minval. */ |
390 | idx = fold_convert (unsigned_index_type, index_expr); | |
391 | idx = fold_build2 (MINUS_EXPR, unsigned_index_type, idx, | |
392 | fold_convert (unsigned_index_type, minval)); | |
78b7a675 | 393 | idx = force_gimple_operand_gsi (&gsi, idx, |
394 | /*simple=*/true, NULL_TREE, | |
395 | /*before=*/true, GSI_SAME_STMT); | |
396 | ||
397 | /* if (idx > range) goto default */ | |
398 | range = force_gimple_operand_gsi (&gsi, | |
399 | fold_convert (unsigned_index_type, range), | |
400 | /*simple=*/true, NULL_TREE, | |
401 | /*before=*/true, GSI_SAME_STMT); | |
402 | tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range); | |
403 | new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, default_edge, update_dom); | |
404 | if (update_dom) | |
f1f41a6c | 405 | bbs_to_fix_dom.quick_push (new_bb); |
78b7a675 | 406 | gcc_assert (gimple_bb (swtch) == new_bb); |
407 | gsi = gsi_last_bb (new_bb); | |
408 | ||
409 | /* Any blocks dominated by the GIMPLE_SWITCH, but that are not successors | |
410 | of NEW_BB, are still immediately dominated by SWITCH_BB. Make it so. */ | |
411 | if (update_dom) | |
412 | { | |
f1f41a6c | 413 | vec<basic_block> dom_bbs; |
78b7a675 | 414 | basic_block dom_son; |
415 | ||
416 | dom_bbs = get_dominated_by (CDI_DOMINATORS, new_bb); | |
f1f41a6c | 417 | FOR_EACH_VEC_ELT (dom_bbs, i, dom_son) |
78b7a675 | 418 | { |
419 | edge e = find_edge (new_bb, dom_son); | |
420 | if (e && single_pred_p (e->dest)) | |
421 | continue; | |
422 | set_immediate_dominator (CDI_DOMINATORS, dom_son, switch_bb); | |
f1f41a6c | 423 | bbs_to_fix_dom.safe_push (dom_son); |
78b7a675 | 424 | } |
f1f41a6c | 425 | dom_bbs.release (); |
78b7a675 | 426 | } |
427 | ||
428 | /* csui = (1 << (word_mode) idx) */ | |
f9e245b2 | 429 | csui = make_ssa_name (word_type_node); |
78b7a675 | 430 | tmp = fold_build2 (LSHIFT_EXPR, word_type_node, word_mode_one, |
431 | fold_convert (word_type_node, idx)); | |
432 | tmp = force_gimple_operand_gsi (&gsi, tmp, | |
433 | /*simple=*/false, NULL_TREE, | |
434 | /*before=*/true, GSI_SAME_STMT); | |
435 | shift_stmt = gimple_build_assign (csui, tmp); | |
78b7a675 | 436 | gsi_insert_before (&gsi, shift_stmt, GSI_SAME_STMT); |
437 | update_stmt (shift_stmt); | |
438 | ||
439 | /* for each unique set of cases: | |
440 | if (const & csui) goto target */ | |
441 | for (k = 0; k < count; k++) | |
442 | { | |
bcf8a30c | 443 | tmp = wide_int_to_tree (word_type_node, test[k].mask); |
78b7a675 | 444 | tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp); |
445 | tmp = force_gimple_operand_gsi (&gsi, tmp, | |
446 | /*simple=*/true, NULL_TREE, | |
447 | /*before=*/true, GSI_SAME_STMT); | |
448 | tmp = fold_build2 (NE_EXPR, boolean_type_node, tmp, word_mode_zero); | |
449 | new_bb = hoist_edge_and_branch_if_true (&gsi, tmp, test[k].target_edge, | |
450 | update_dom); | |
451 | if (update_dom) | |
f1f41a6c | 452 | bbs_to_fix_dom.safe_push (new_bb); |
78b7a675 | 453 | gcc_assert (gimple_bb (swtch) == new_bb); |
454 | gsi = gsi_last_bb (new_bb); | |
455 | } | |
456 | ||
457 | /* We should have removed all edges now. */ | |
458 | gcc_assert (EDGE_COUNT (gsi_bb (gsi)->succs) == 0); | |
459 | ||
460 | /* If nothing matched, go to the default label. */ | |
461 | make_edge (gsi_bb (gsi), new_default_bb, EDGE_FALLTHRU); | |
462 | ||
463 | /* The GIMPLE_SWITCH is now redundant. */ | |
464 | gsi_remove (&gsi, true); | |
465 | ||
466 | if (update_dom) | |
467 | { | |
468 | /* Fix up the dominator tree. */ | |
469 | iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
f1f41a6c | 470 | bbs_to_fix_dom.release (); |
78b7a675 | 471 | } |
472 | } | |
473 | \f | |
a347af29 | 474 | /* |
475 | Switch initialization conversion | |
476 | ||
477 | The following pass changes simple initializations of scalars in a switch | |
5d459527 | 478 | statement into initializations from a static array. Obviously, the values |
479 | must be constant and known at compile time and a default branch must be | |
a347af29 | 480 | provided. For example, the following code: |
481 | ||
482 | int a,b; | |
483 | ||
484 | switch (argc) | |
485 | { | |
486 | case 1: | |
487 | case 2: | |
488 | a_1 = 8; | |
489 | b_1 = 6; | |
490 | break; | |
491 | case 3: | |
492 | a_2 = 9; | |
493 | b_2 = 5; | |
494 | break; | |
495 | case 12: | |
496 | a_3 = 10; | |
497 | b_3 = 4; | |
498 | break; | |
499 | default: | |
500 | a_4 = 16; | |
501 | b_4 = 1; | |
11f2f313 | 502 | break; |
a347af29 | 503 | } |
504 | a_5 = PHI <a_1, a_2, a_3, a_4> | |
505 | b_5 = PHI <b_1, b_2, b_3, b_4> | |
506 | ||
507 | ||
508 | is changed into: | |
509 | ||
510 | static const int = CSWTCH01[] = {6, 6, 5, 1, 1, 1, 1, 1, 1, 1, 1, 4}; | |
511 | static const int = CSWTCH02[] = {8, 8, 9, 16, 16, 16, 16, 16, 16, 16, | |
512 | 16, 16, 10}; | |
513 | ||
514 | if (((unsigned) argc) - 1 < 11) | |
515 | { | |
516 | a_6 = CSWTCH02[argc - 1]; | |
517 | b_6 = CSWTCH01[argc - 1]; | |
518 | } | |
519 | else | |
520 | { | |
521 | a_7 = 16; | |
522 | b_7 = 1; | |
523 | } | |
11f2f313 | 524 | a_5 = PHI <a_6, a_7> |
525 | b_b = PHI <b_6, b_7> | |
a347af29 | 526 | |
527 | There are further constraints. Specifically, the range of values across all | |
528 | case labels must not be bigger than SWITCH_CONVERSION_BRANCH_RATIO (default | |
78b7a675 | 529 | eight) times the number of the actual switch branches. |
a347af29 | 530 | |
78b7a675 | 531 | This transformation was contributed by Martin Jambor, see this e-mail: |
532 | http://gcc.gnu.org/ml/gcc-patches/2008-07/msg00011.html */ | |
a347af29 | 533 | |
534 | /* The main structure of the pass. */ | |
535 | struct switch_conv_info | |
536 | { | |
11f2f313 | 537 | /* The expression used to decide the switch branch. */ |
a347af29 | 538 | tree index_expr; |
539 | ||
11f2f313 | 540 | /* The following integer constants store the minimum and maximum value |
541 | covered by the case labels. */ | |
a347af29 | 542 | tree range_min; |
11f2f313 | 543 | tree range_max; |
a347af29 | 544 | |
11f2f313 | 545 | /* The difference between the above two numbers. Stored here because it |
546 | is used in all the conversion heuristics, as well as for some of the | |
547 | transformation, and it is expensive to re-compute it all the time. */ | |
a347af29 | 548 | tree range_size; |
549 | ||
11f2f313 | 550 | /* Basic block that contains the actual GIMPLE_SWITCH. */ |
a347af29 | 551 | basic_block switch_bb; |
552 | ||
11f2f313 | 553 | /* Basic block that is the target of the default case. */ |
554 | basic_block default_bb; | |
555 | ||
556 | /* The single successor block of all branches out of the GIMPLE_SWITCH, | |
557 | if such a block exists. Otherwise NULL. */ | |
a347af29 | 558 | basic_block final_bb; |
559 | ||
11f2f313 | 560 | /* The probability of the default edge in the replaced switch. */ |
561 | int default_prob; | |
562 | ||
563 | /* The count of the default edge in the replaced switch. */ | |
db9cef39 | 564 | profile_count default_count; |
11f2f313 | 565 | |
566 | /* Combined count of all other (non-default) edges in the replaced switch. */ | |
db9cef39 | 567 | profile_count other_count; |
11f2f313 | 568 | |
a347af29 | 569 | /* Number of phi nodes in the final bb (that we'll be replacing). */ |
570 | int phi_count; | |
571 | ||
cc17b19b | 572 | /* Array of default values, in the same order as phi nodes. */ |
a347af29 | 573 | tree *default_values; |
574 | ||
575 | /* Constructors of new static arrays. */ | |
f1f41a6c | 576 | vec<constructor_elt, va_gc> **constructors; |
a347af29 | 577 | |
578 | /* Array of ssa names that are initialized with a value from a new static | |
579 | array. */ | |
580 | tree *target_inbound_names; | |
581 | ||
582 | /* Array of ssa names that are initialized with the default value if the | |
583 | switch expression is out of range. */ | |
584 | tree *target_outbound_names; | |
585 | ||
7992e6b5 | 586 | /* VOP SSA_NAME. */ |
587 | tree target_vop; | |
588 | ||
cc17b19b | 589 | /* The first load statement that loads a temporary from a new static array. |
590 | */ | |
42acab1c | 591 | gimple *arr_ref_first; |
a347af29 | 592 | |
593 | /* The last load statement that loads a temporary from a new static array. */ | |
42acab1c | 594 | gimple *arr_ref_last; |
a347af29 | 595 | |
596 | /* String reason why the case wasn't a good candidate that is written to the | |
597 | dump file, if there is one. */ | |
598 | const char *reason; | |
df2813c5 | 599 | |
c66f9851 | 600 | /* True if default case is not used for any value between range_min and |
601 | range_max inclusive. */ | |
602 | bool contiguous_range; | |
603 | ||
604 | /* True if default case does not have the required shape for other case | |
605 | labels. */ | |
606 | bool default_case_nonstandard; | |
607 | ||
df2813c5 | 608 | /* Parameters for expand_switch_using_bit_tests. Should be computed |
609 | the same way as in expand_case. */ | |
11f2f313 | 610 | unsigned int uniq; |
611 | unsigned int count; | |
a347af29 | 612 | }; |
613 | ||
11f2f313 | 614 | /* Collect information about GIMPLE_SWITCH statement SWTCH into INFO. */ |
a347af29 | 615 | |
11f2f313 | 616 | static void |
1a91d914 | 617 | collect_switch_conv_info (gswitch *swtch, struct switch_conv_info *info) |
a347af29 | 618 | { |
75a70cf9 | 619 | unsigned int branch_num = gimple_switch_num_labels (swtch); |
11f2f313 | 620 | tree min_case, max_case; |
621 | unsigned int count, i; | |
c66f9851 | 622 | edge e, e_default, e_first; |
11f2f313 | 623 | edge_iterator ei; |
c66f9851 | 624 | basic_block first; |
11f2f313 | 625 | |
626 | memset (info, 0, sizeof (*info)); | |
a347af29 | 627 | |
628 | /* The gimplifier has already sorted the cases by CASE_LOW and ensured there | |
49a70175 | 629 | is a default label which is the first in the vector. |
630 | Collect the bits we can deduce from the CFG. */ | |
11f2f313 | 631 | info->index_expr = gimple_switch_index (swtch); |
632 | info->switch_bb = gimple_bb (swtch); | |
c66f9851 | 633 | info->default_bb |
634 | = label_to_block (CASE_LABEL (gimple_switch_default_label (swtch))); | |
11f2f313 | 635 | e_default = find_edge (info->switch_bb, info->default_bb); |
636 | info->default_prob = e_default->probability; | |
637 | info->default_count = e_default->count; | |
638 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
639 | if (e != e_default) | |
640 | info->other_count += e->count; | |
a347af29 | 641 | |
c66f9851 | 642 | /* Get upper and lower bounds of case values, and the covered range. */ |
643 | min_case = gimple_switch_label (swtch, 1); | |
644 | max_case = gimple_switch_label (swtch, branch_num - 1); | |
645 | ||
646 | info->range_min = CASE_LOW (min_case); | |
647 | if (CASE_HIGH (max_case) != NULL_TREE) | |
648 | info->range_max = CASE_HIGH (max_case); | |
649 | else | |
650 | info->range_max = CASE_LOW (max_case); | |
651 | ||
652 | info->contiguous_range = true; | |
653 | tree last = CASE_HIGH (min_case) ? CASE_HIGH (min_case) : info->range_min; | |
654 | for (i = 2; i < branch_num; i++) | |
655 | { | |
656 | tree elt = gimple_switch_label (swtch, i); | |
657 | wide_int w = last; | |
658 | if (w + 1 != CASE_LOW (elt)) | |
659 | { | |
660 | info->contiguous_range = false; | |
661 | break; | |
662 | } | |
663 | last = CASE_HIGH (elt) ? CASE_HIGH (elt) : CASE_LOW (elt); | |
664 | } | |
665 | ||
666 | if (info->contiguous_range) | |
667 | { | |
668 | first = label_to_block (CASE_LABEL (gimple_switch_label (swtch, 1))); | |
669 | e_first = find_edge (info->switch_bb, first); | |
670 | } | |
671 | else | |
672 | { | |
673 | first = info->default_bb; | |
674 | e_first = e_default; | |
675 | } | |
676 | ||
11f2f313 | 677 | /* See if there is one common successor block for all branch |
1c36b19f | 678 | targets. If it exists, record it in FINAL_BB. |
c66f9851 | 679 | Start with the destination of the first non-default case |
680 | if the range is contiguous and default case otherwise as | |
681 | guess or its destination in case it is a forwarder block. */ | |
682 | if (! single_pred_p (e_first->dest)) | |
683 | info->final_bb = e_first->dest; | |
684 | else if (single_succ_p (e_first->dest) | |
685 | && ! single_pred_p (single_succ (e_first->dest))) | |
686 | info->final_bb = single_succ (e_first->dest); | |
1c36b19f | 687 | /* Require that all switch destinations are either that common |
c66f9851 | 688 | FINAL_BB or a forwarder to it, except for the default |
689 | case if contiguous range. */ | |
11f2f313 | 690 | if (info->final_bb) |
691 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
692 | { | |
693 | if (e->dest == info->final_bb) | |
694 | continue; | |
695 | ||
696 | if (single_pred_p (e->dest) | |
697 | && single_succ_p (e->dest) | |
698 | && single_succ (e->dest) == info->final_bb) | |
699 | continue; | |
700 | ||
c66f9851 | 701 | if (e == e_default && info->contiguous_range) |
702 | { | |
703 | info->default_case_nonstandard = true; | |
704 | continue; | |
705 | } | |
706 | ||
11f2f313 | 707 | info->final_bb = NULL; |
708 | break; | |
709 | } | |
710 | ||
c66f9851 | 711 | info->range_size |
712 | = int_const_binop (MINUS_EXPR, info->range_max, info->range_min); | |
a347af29 | 713 | |
11f2f313 | 714 | /* Get a count of the number of case labels. Single-valued case labels |
715 | simply count as one, but a case range counts double, since it may | |
716 | require two compares if it gets lowered as a branching tree. */ | |
717 | count = 0; | |
718 | for (i = 1; i < branch_num; i++) | |
719 | { | |
720 | tree elt = gimple_switch_label (swtch, i); | |
721 | count++; | |
722 | if (CASE_HIGH (elt) | |
723 | && ! tree_int_cst_equal (CASE_LOW (elt), CASE_HIGH (elt))) | |
724 | count++; | |
725 | } | |
726 | info->count = count; | |
727 | ||
728 | /* Get the number of unique non-default targets out of the GIMPLE_SWITCH | |
729 | block. Assume a CFG cleanup would have already removed degenerate | |
730 | switch statements, this allows us to just use EDGE_COUNT. */ | |
731 | info->uniq = EDGE_COUNT (gimple_bb (swtch)->succs) - 1; | |
732 | } | |
a347af29 | 733 | |
11f2f313 | 734 | /* Checks whether the range given by individual case statements of the SWTCH |
735 | switch statement isn't too big and whether the number of branches actually | |
736 | satisfies the size of the new array. */ | |
a347af29 | 737 | |
11f2f313 | 738 | static bool |
739 | check_range (struct switch_conv_info *info) | |
740 | { | |
5d459527 | 741 | gcc_assert (info->range_size); |
e913b5cd | 742 | if (!tree_fits_uhwi_p (info->range_size)) |
a347af29 | 743 | { |
5d459527 | 744 | info->reason = "index range way too large or otherwise unusable"; |
a347af29 | 745 | return false; |
746 | } | |
747 | ||
aa59f000 | 748 | if (tree_to_uhwi (info->range_size) |
11f2f313 | 749 | > ((unsigned) info->count * SWITCH_CONVERSION_BRANCH_RATIO)) |
a347af29 | 750 | { |
5d459527 | 751 | info->reason = "the maximum range-branch ratio exceeded"; |
a347af29 | 752 | return false; |
753 | } | |
754 | ||
755 | return true; | |
756 | } | |
757 | ||
11f2f313 | 758 | /* Checks whether all but the FINAL_BB basic blocks are empty. */ |
a347af29 | 759 | |
760 | static bool | |
11f2f313 | 761 | check_all_empty_except_final (struct switch_conv_info *info) |
a347af29 | 762 | { |
c66f9851 | 763 | edge e, e_default = find_edge (info->switch_bb, info->default_bb); |
11f2f313 | 764 | edge_iterator ei; |
a347af29 | 765 | |
11f2f313 | 766 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) |
a347af29 | 767 | { |
11f2f313 | 768 | if (e->dest == info->final_bb) |
769 | continue; | |
a347af29 | 770 | |
11f2f313 | 771 | if (!empty_block_p (e->dest)) |
a347af29 | 772 | { |
c66f9851 | 773 | if (info->contiguous_range && e == e_default) |
774 | { | |
775 | info->default_case_nonstandard = true; | |
776 | continue; | |
777 | } | |
778 | ||
5d459527 | 779 | info->reason = "bad case - a non-final BB not empty"; |
a347af29 | 780 | return false; |
781 | } | |
a347af29 | 782 | } |
783 | ||
784 | return true; | |
785 | } | |
786 | ||
787 | /* This function checks whether all required values in phi nodes in final_bb | |
788 | are constants. Required values are those that correspond to a basic block | |
789 | which is a part of the examined switch statement. It returns true if the | |
790 | phi nodes are OK, otherwise false. */ | |
791 | ||
792 | static bool | |
c66f9851 | 793 | check_final_bb (gswitch *swtch, struct switch_conv_info *info) |
a347af29 | 794 | { |
1a91d914 | 795 | gphi_iterator gsi; |
a347af29 | 796 | |
5d459527 | 797 | info->phi_count = 0; |
798 | for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
a347af29 | 799 | { |
1a91d914 | 800 | gphi *phi = gsi.phi (); |
75a70cf9 | 801 | unsigned int i; |
a347af29 | 802 | |
c66f9851 | 803 | if (virtual_operand_p (gimple_phi_result (phi))) |
804 | continue; | |
805 | ||
5d459527 | 806 | info->phi_count++; |
a347af29 | 807 | |
75a70cf9 | 808 | for (i = 0; i < gimple_phi_num_args (phi); i++) |
a347af29 | 809 | { |
75a70cf9 | 810 | basic_block bb = gimple_phi_arg_edge (phi, i)->src; |
a347af29 | 811 | |
5d459527 | 812 | if (bb == info->switch_bb |
c66f9851 | 813 | || (single_pred_p (bb) |
814 | && single_pred (bb) == info->switch_bb | |
815 | && (!info->default_case_nonstandard | |
816 | || empty_block_p (bb)))) | |
a347af29 | 817 | { |
54af7f7e | 818 | tree reloc, val; |
c66f9851 | 819 | const char *reason = NULL; |
54af7f7e | 820 | |
821 | val = gimple_phi_arg_def (phi, i); | |
822 | if (!is_gimple_ip_invariant (val)) | |
c66f9851 | 823 | reason = "non-invariant value from a case"; |
824 | else | |
54af7f7e | 825 | { |
c66f9851 | 826 | reloc = initializer_constant_valid_p (val, TREE_TYPE (val)); |
827 | if ((flag_pic && reloc != null_pointer_node) | |
828 | || (!flag_pic && reloc == NULL_TREE)) | |
829 | { | |
830 | if (reloc) | |
831 | reason | |
832 | = "value from a case would need runtime relocations"; | |
833 | else | |
834 | reason | |
835 | = "value from a case is not a valid initializer"; | |
836 | } | |
54af7f7e | 837 | } |
c66f9851 | 838 | if (reason) |
54af7f7e | 839 | { |
c66f9851 | 840 | /* For contiguous range, we can allow non-constant |
841 | or one that needs relocation, as long as it is | |
842 | only reachable from the default case. */ | |
843 | if (bb == info->switch_bb) | |
844 | bb = info->final_bb; | |
845 | if (!info->contiguous_range || bb != info->default_bb) | |
846 | { | |
847 | info->reason = reason; | |
848 | return false; | |
849 | } | |
850 | ||
851 | unsigned int branch_num = gimple_switch_num_labels (swtch); | |
852 | for (unsigned int i = 1; i < branch_num; i++) | |
853 | { | |
854 | tree lab = CASE_LABEL (gimple_switch_label (swtch, i)); | |
855 | if (label_to_block (lab) == bb) | |
856 | { | |
857 | info->reason = reason; | |
858 | return false; | |
859 | } | |
860 | } | |
861 | info->default_case_nonstandard = true; | |
54af7f7e | 862 | } |
a347af29 | 863 | } |
864 | } | |
865 | } | |
866 | ||
867 | return true; | |
868 | } | |
869 | ||
870 | /* The following function allocates default_values, target_{in,out}_names and | |
871 | constructors arrays. The last one is also populated with pointers to | |
872 | vectors that will become constructors of new arrays. */ | |
873 | ||
874 | static void | |
5d459527 | 875 | create_temp_arrays (struct switch_conv_info *info) |
a347af29 | 876 | { |
877 | int i; | |
878 | ||
5d459527 | 879 | info->default_values = XCNEWVEC (tree, info->phi_count * 3); |
f1f41a6c | 880 | /* ??? Macros do not support multi argument templates in their |
881 | argument list. We create a typedef to work around that problem. */ | |
882 | typedef vec<constructor_elt, va_gc> *vec_constructor_elt_gc; | |
883 | info->constructors = XCNEWVEC (vec_constructor_elt_gc, info->phi_count); | |
5d459527 | 884 | info->target_inbound_names = info->default_values + info->phi_count; |
885 | info->target_outbound_names = info->target_inbound_names + info->phi_count; | |
886 | for (i = 0; i < info->phi_count; i++) | |
e913b5cd | 887 | vec_alloc (info->constructors[i], tree_to_uhwi (info->range_size) + 1); |
a347af29 | 888 | } |
889 | ||
890 | /* Free the arrays created by create_temp_arrays(). The vectors that are | |
891 | created by that function are not freed here, however, because they have | |
892 | already become constructors and must be preserved. */ | |
893 | ||
894 | static void | |
5d459527 | 895 | free_temp_arrays (struct switch_conv_info *info) |
a347af29 | 896 | { |
5d459527 | 897 | XDELETEVEC (info->constructors); |
898 | XDELETEVEC (info->default_values); | |
a347af29 | 899 | } |
900 | ||
901 | /* Populate the array of default values in the order of phi nodes. | |
c66f9851 | 902 | DEFAULT_CASE is the CASE_LABEL_EXPR for the default switch branch |
903 | if the range is non-contiguous or the default case has standard | |
904 | structure, otherwise it is the first non-default case instead. */ | |
a347af29 | 905 | |
906 | static void | |
5d459527 | 907 | gather_default_values (tree default_case, struct switch_conv_info *info) |
a347af29 | 908 | { |
1a91d914 | 909 | gphi_iterator gsi; |
a347af29 | 910 | basic_block bb = label_to_block (CASE_LABEL (default_case)); |
911 | edge e; | |
75a70cf9 | 912 | int i = 0; |
a347af29 | 913 | |
c66f9851 | 914 | gcc_assert (CASE_LOW (default_case) == NULL_TREE |
915 | || info->default_case_nonstandard); | |
a347af29 | 916 | |
5d459527 | 917 | if (bb == info->final_bb) |
918 | e = find_edge (info->switch_bb, bb); | |
a347af29 | 919 | else |
920 | e = single_succ_edge (bb); | |
921 | ||
5d459527 | 922 | for (gsi = gsi_start_phis (info->final_bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
a347af29 | 923 | { |
1a91d914 | 924 | gphi *phi = gsi.phi (); |
c66f9851 | 925 | if (virtual_operand_p (gimple_phi_result (phi))) |
926 | continue; | |
a347af29 | 927 | tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
928 | gcc_assert (val); | |
5d459527 | 929 | info->default_values[i++] = val; |
a347af29 | 930 | } |
931 | } | |
932 | ||
933 | /* The following function populates the vectors in the constructors array with | |
934 | future contents of the static arrays. The vectors are populated in the | |
935 | order of phi nodes. SWTCH is the switch statement being converted. */ | |
936 | ||
937 | static void | |
1a91d914 | 938 | build_constructors (gswitch *swtch, struct switch_conv_info *info) |
a347af29 | 939 | { |
75a70cf9 | 940 | unsigned i, branch_num = gimple_switch_num_labels (swtch); |
5d459527 | 941 | tree pos = info->range_min; |
c66f9851 | 942 | tree pos_one = build_int_cst (TREE_TYPE (pos), 1); |
a347af29 | 943 | |
75a70cf9 | 944 | for (i = 1; i < branch_num; i++) |
a347af29 | 945 | { |
75a70cf9 | 946 | tree cs = gimple_switch_label (swtch, i); |
a347af29 | 947 | basic_block bb = label_to_block (CASE_LABEL (cs)); |
948 | edge e; | |
75a70cf9 | 949 | tree high; |
1a91d914 | 950 | gphi_iterator gsi; |
a347af29 | 951 | int j; |
952 | ||
5d459527 | 953 | if (bb == info->final_bb) |
954 | e = find_edge (info->switch_bb, bb); | |
a347af29 | 955 | else |
956 | e = single_succ_edge (bb); | |
957 | gcc_assert (e); | |
958 | ||
959 | while (tree_int_cst_lt (pos, CASE_LOW (cs))) | |
960 | { | |
961 | int k; | |
c66f9851 | 962 | gcc_assert (!info->contiguous_range); |
5d459527 | 963 | for (k = 0; k < info->phi_count; k++) |
a347af29 | 964 | { |
e82e4eb5 | 965 | constructor_elt elt; |
a347af29 | 966 | |
e82e4eb5 | 967 | elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); |
827e392b | 968 | elt.value |
969 | = unshare_expr_without_location (info->default_values[k]); | |
f1f41a6c | 970 | info->constructors[k]->quick_push (elt); |
a347af29 | 971 | } |
972 | ||
c66f9851 | 973 | pos = int_const_binop (PLUS_EXPR, pos, pos_one); |
a347af29 | 974 | } |
cc17b19b | 975 | gcc_assert (tree_int_cst_equal (pos, CASE_LOW (cs))); |
a347af29 | 976 | |
977 | j = 0; | |
978 | if (CASE_HIGH (cs)) | |
979 | high = CASE_HIGH (cs); | |
980 | else | |
cc17b19b | 981 | high = CASE_LOW (cs); |
5d459527 | 982 | for (gsi = gsi_start_phis (info->final_bb); |
75a70cf9 | 983 | !gsi_end_p (gsi); gsi_next (&gsi)) |
a347af29 | 984 | { |
1a91d914 | 985 | gphi *phi = gsi.phi (); |
c66f9851 | 986 | if (virtual_operand_p (gimple_phi_result (phi))) |
987 | continue; | |
a347af29 | 988 | tree val = PHI_ARG_DEF_FROM_EDGE (phi, e); |
7558c999 | 989 | tree low = CASE_LOW (cs); |
a347af29 | 990 | pos = CASE_LOW (cs); |
991 | ||
48e1416a | 992 | do |
a347af29 | 993 | { |
e82e4eb5 | 994 | constructor_elt elt; |
a347af29 | 995 | |
e82e4eb5 | 996 | elt.index = int_const_binop (MINUS_EXPR, pos, info->range_min); |
827e392b | 997 | elt.value = unshare_expr_without_location (val); |
f1f41a6c | 998 | info->constructors[j]->quick_push (elt); |
a347af29 | 999 | |
c66f9851 | 1000 | pos = int_const_binop (PLUS_EXPR, pos, pos_one); |
f6ac75a7 | 1001 | } while (!tree_int_cst_lt (high, pos) |
1002 | && tree_int_cst_lt (low, pos)); | |
a347af29 | 1003 | j++; |
1004 | } | |
1005 | } | |
1006 | } | |
1007 | ||
f6ac75a7 | 1008 | /* If all values in the constructor vector are the same, return the value. |
1009 | Otherwise return NULL_TREE. Not supposed to be called for empty | |
1010 | vectors. */ | |
1011 | ||
1012 | static tree | |
f1f41a6c | 1013 | constructor_contains_same_values_p (vec<constructor_elt, va_gc> *vec) |
f6ac75a7 | 1014 | { |
df2813c5 | 1015 | unsigned int i; |
f6ac75a7 | 1016 | tree prev = NULL_TREE; |
df2813c5 | 1017 | constructor_elt *elt; |
f6ac75a7 | 1018 | |
f1f41a6c | 1019 | FOR_EACH_VEC_SAFE_ELT (vec, i, elt) |
f6ac75a7 | 1020 | { |
f6ac75a7 | 1021 | if (!prev) |
1022 | prev = elt->value; | |
1023 | else if (!operand_equal_p (elt->value, prev, OEP_ONLY_CONST)) | |
1024 | return NULL_TREE; | |
1025 | } | |
1026 | return prev; | |
1027 | } | |
1028 | ||
ec4f3cf1 | 1029 | /* Return type which should be used for array elements, either TYPE's |
1030 | main variant or, for integral types, some smaller integral type | |
1031 | that can still hold all the constants. */ | |
df2813c5 | 1032 | |
1033 | static tree | |
1a91d914 | 1034 | array_value_type (gswitch *swtch, tree type, int num, |
5d459527 | 1035 | struct switch_conv_info *info) |
df2813c5 | 1036 | { |
f1f41a6c | 1037 | unsigned int i, len = vec_safe_length (info->constructors[num]); |
df2813c5 | 1038 | constructor_elt *elt; |
3754d046 | 1039 | machine_mode mode; |
df2813c5 | 1040 | int sign = 0; |
1041 | tree smaller_type; | |
1042 | ||
ec4f3cf1 | 1043 | /* Types with alignments greater than their size can reach here, e.g. out of |
1044 | SRA. We couldn't use these as an array component type so get back to the | |
1045 | main variant first, which, for our purposes, is fine for other types as | |
1046 | well. */ | |
1047 | ||
1048 | type = TYPE_MAIN_VARIANT (type); | |
1049 | ||
df2813c5 | 1050 | if (!INTEGRAL_TYPE_P (type)) |
1051 | return type; | |
1052 | ||
1053 | mode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (TYPE_MODE (type))); | |
1054 | if (GET_MODE_SIZE (TYPE_MODE (type)) <= GET_MODE_SIZE (mode)) | |
1055 | return type; | |
1056 | ||
1057 | if (len < (optimize_bb_for_size_p (gimple_bb (swtch)) ? 2 : 32)) | |
1058 | return type; | |
1059 | ||
f1f41a6c | 1060 | FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
df2813c5 | 1061 | { |
e913b5cd | 1062 | wide_int cst; |
df2813c5 | 1063 | |
1064 | if (TREE_CODE (elt->value) != INTEGER_CST) | |
1065 | return type; | |
1066 | ||
e913b5cd | 1067 | cst = elt->value; |
df2813c5 | 1068 | while (1) |
1069 | { | |
1070 | unsigned int prec = GET_MODE_BITSIZE (mode); | |
1071 | if (prec > HOST_BITS_PER_WIDE_INT) | |
1072 | return type; | |
1073 | ||
796b6678 | 1074 | if (sign >= 0 && cst == wi::zext (cst, prec)) |
df2813c5 | 1075 | { |
796b6678 | 1076 | if (sign == 0 && cst == wi::sext (cst, prec)) |
df2813c5 | 1077 | break; |
1078 | sign = 1; | |
1079 | break; | |
1080 | } | |
796b6678 | 1081 | if (sign <= 0 && cst == wi::sext (cst, prec)) |
df2813c5 | 1082 | { |
1083 | sign = -1; | |
1084 | break; | |
1085 | } | |
1086 | ||
1087 | if (sign == 1) | |
1088 | sign = 0; | |
1089 | ||
1090 | mode = GET_MODE_WIDER_MODE (mode); | |
1091 | if (mode == VOIDmode | |
1092 | || GET_MODE_SIZE (mode) >= GET_MODE_SIZE (TYPE_MODE (type))) | |
1093 | return type; | |
1094 | } | |
1095 | } | |
1096 | ||
1097 | if (sign == 0) | |
1098 | sign = TYPE_UNSIGNED (type) ? 1 : -1; | |
1099 | smaller_type = lang_hooks.types.type_for_mode (mode, sign >= 0); | |
1100 | if (GET_MODE_SIZE (TYPE_MODE (type)) | |
1101 | <= GET_MODE_SIZE (TYPE_MODE (smaller_type))) | |
1102 | return type; | |
1103 | ||
1104 | return smaller_type; | |
1105 | } | |
1106 | ||
a347af29 | 1107 | /* Create an appropriate array type and declaration and assemble a static array |
1108 | variable. Also create a load statement that initializes the variable in | |
1109 | question with a value from the static array. SWTCH is the switch statement | |
1110 | being converted, NUM is the index to arrays of constructors, default values | |
1111 | and target SSA names for this particular array. ARR_INDEX_TYPE is the type | |
1112 | of the index of the new array, PHI is the phi node of the final BB that | |
1113 | corresponds to the value that will be loaded from the created array. TIDX | |
f6ac75a7 | 1114 | is an ssa name of a temporary variable holding the index for loads from the |
1115 | new array. */ | |
a347af29 | 1116 | |
1117 | static void | |
1a91d914 | 1118 | build_one_array (gswitch *swtch, int num, tree arr_index_type, |
1119 | gphi *phi, tree tidx, struct switch_conv_info *info) | |
a347af29 | 1120 | { |
f6ac75a7 | 1121 | tree name, cst; |
42acab1c | 1122 | gimple *load; |
f6ac75a7 | 1123 | gimple_stmt_iterator gsi = gsi_for_stmt (swtch); |
e60a6f7b | 1124 | location_t loc = gimple_location (swtch); |
a347af29 | 1125 | |
5d459527 | 1126 | gcc_assert (info->default_values[num]); |
a347af29 | 1127 | |
f9e245b2 | 1128 | name = copy_ssa_name (PHI_RESULT (phi)); |
5d459527 | 1129 | info->target_inbound_names[num] = name; |
a347af29 | 1130 | |
5d459527 | 1131 | cst = constructor_contains_same_values_p (info->constructors[num]); |
f6ac75a7 | 1132 | if (cst) |
1133 | load = gimple_build_assign (name, cst); | |
1134 | else | |
1135 | { | |
df2813c5 | 1136 | tree array_type, ctor, decl, value_type, fetch, default_type; |
f6ac75a7 | 1137 | |
5d459527 | 1138 | default_type = TREE_TYPE (info->default_values[num]); |
1139 | value_type = array_value_type (swtch, default_type, num, info); | |
f6ac75a7 | 1140 | array_type = build_array_type (value_type, arr_index_type); |
df2813c5 | 1141 | if (default_type != value_type) |
1142 | { | |
1143 | unsigned int i; | |
1144 | constructor_elt *elt; | |
1145 | ||
f1f41a6c | 1146 | FOR_EACH_VEC_SAFE_ELT (info->constructors[num], i, elt) |
df2813c5 | 1147 | elt->value = fold_convert (value_type, elt->value); |
1148 | } | |
5d459527 | 1149 | ctor = build_constructor (array_type, info->constructors[num]); |
f6ac75a7 | 1150 | TREE_CONSTANT (ctor) = true; |
e579afdd | 1151 | TREE_STATIC (ctor) = true; |
f6ac75a7 | 1152 | |
e60a6f7b | 1153 | decl = build_decl (loc, VAR_DECL, NULL_TREE, array_type); |
f6ac75a7 | 1154 | TREE_STATIC (decl) = 1; |
1155 | DECL_INITIAL (decl) = ctor; | |
1156 | ||
1157 | DECL_NAME (decl) = create_tmp_var_name ("CSWTCH"); | |
1158 | DECL_ARTIFICIAL (decl) = 1; | |
0f9e75c9 | 1159 | DECL_IGNORED_P (decl) = 1; |
f6ac75a7 | 1160 | TREE_CONSTANT (decl) = 1; |
e7baf91d | 1161 | TREE_READONLY (decl) = 1; |
3a1c9df2 | 1162 | DECL_IGNORED_P (decl) = 1; |
97221fd7 | 1163 | varpool_node::finalize_decl (decl); |
f6ac75a7 | 1164 | |
1165 | fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE, | |
1166 | NULL_TREE); | |
df2813c5 | 1167 | if (default_type != value_type) |
1168 | { | |
1169 | fetch = fold_convert (default_type, fetch); | |
1170 | fetch = force_gimple_operand_gsi (&gsi, fetch, true, NULL_TREE, | |
1171 | true, GSI_SAME_STMT); | |
1172 | } | |
f6ac75a7 | 1173 | load = gimple_build_assign (name, fetch); |
1174 | } | |
a347af29 | 1175 | |
75a70cf9 | 1176 | gsi_insert_before (&gsi, load, GSI_SAME_STMT); |
f6ac75a7 | 1177 | update_stmt (load); |
5d459527 | 1178 | info->arr_ref_last = load; |
a347af29 | 1179 | } |
1180 | ||
1181 | /* Builds and initializes static arrays initialized with values gathered from | |
1182 | the SWTCH switch statement. Also creates statements that load values from | |
1183 | them. */ | |
1184 | ||
1185 | static void | |
1a91d914 | 1186 | build_arrays (gswitch *swtch, struct switch_conv_info *info) |
a347af29 | 1187 | { |
1188 | tree arr_index_type; | |
03d37e4e | 1189 | tree tidx, sub, utype; |
42acab1c | 1190 | gimple *stmt; |
75a70cf9 | 1191 | gimple_stmt_iterator gsi; |
1a91d914 | 1192 | gphi_iterator gpi; |
a347af29 | 1193 | int i; |
389dd41b | 1194 | location_t loc = gimple_location (swtch); |
a347af29 | 1195 | |
75a70cf9 | 1196 | gsi = gsi_for_stmt (swtch); |
49a931ef | 1197 | |
8853d378 | 1198 | /* Make sure we do not generate arithmetics in a subrange. */ |
5d459527 | 1199 | utype = TREE_TYPE (info->index_expr); |
8853d378 | 1200 | if (TREE_TYPE (utype)) |
1201 | utype = lang_hooks.types.type_for_mode (TYPE_MODE (TREE_TYPE (utype)), 1); | |
1202 | else | |
1203 | utype = lang_hooks.types.type_for_mode (TYPE_MODE (utype), 1); | |
1204 | ||
5d459527 | 1205 | arr_index_type = build_index_type (info->range_size); |
f9e245b2 | 1206 | tidx = make_ssa_name (utype); |
8853d378 | 1207 | sub = fold_build2_loc (loc, MINUS_EXPR, utype, |
5d459527 | 1208 | fold_convert_loc (loc, utype, info->index_expr), |
1209 | fold_convert_loc (loc, utype, info->range_min)); | |
42d9ffa5 | 1210 | sub = force_gimple_operand_gsi (&gsi, sub, |
75a70cf9 | 1211 | false, NULL, true, GSI_SAME_STMT); |
1212 | stmt = gimple_build_assign (tidx, sub); | |
a347af29 | 1213 | |
75a70cf9 | 1214 | gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); |
f6ac75a7 | 1215 | update_stmt (stmt); |
5d459527 | 1216 | info->arr_ref_first = stmt; |
a347af29 | 1217 | |
1a91d914 | 1218 | for (gpi = gsi_start_phis (info->final_bb), i = 0; |
c66f9851 | 1219 | !gsi_end_p (gpi); gsi_next (&gpi)) |
1220 | { | |
1221 | gphi *phi = gpi.phi (); | |
1222 | if (!virtual_operand_p (gimple_phi_result (phi))) | |
1223 | build_one_array (swtch, i++, arr_index_type, phi, tidx, info); | |
7992e6b5 | 1224 | else |
1225 | { | |
1226 | edge e; | |
1227 | edge_iterator ei; | |
1228 | FOR_EACH_EDGE (e, ei, info->switch_bb->succs) | |
1229 | { | |
1230 | if (e->dest == info->final_bb) | |
1231 | break; | |
1232 | if (!info->default_case_nonstandard | |
1233 | || e->dest != info->default_bb) | |
1234 | { | |
1235 | e = single_succ_edge (e->dest); | |
1236 | break; | |
1237 | } | |
1238 | } | |
1239 | gcc_assert (e && e->dest == info->final_bb); | |
1240 | info->target_vop = PHI_ARG_DEF_FROM_EDGE (phi, e); | |
1241 | } | |
c66f9851 | 1242 | } |
a347af29 | 1243 | } |
1244 | ||
1245 | /* Generates and appropriately inserts loads of default values at the position | |
1246 | given by BSI. Returns the last inserted statement. */ | |
1247 | ||
1a91d914 | 1248 | static gassign * |
5d459527 | 1249 | gen_def_assigns (gimple_stmt_iterator *gsi, struct switch_conv_info *info) |
a347af29 | 1250 | { |
1251 | int i; | |
1a91d914 | 1252 | gassign *assign = NULL; |
a347af29 | 1253 | |
5d459527 | 1254 | for (i = 0; i < info->phi_count; i++) |
a347af29 | 1255 | { |
f9e245b2 | 1256 | tree name = copy_ssa_name (info->target_inbound_names[i]); |
5d459527 | 1257 | info->target_outbound_names[i] = name; |
1258 | assign = gimple_build_assign (name, info->default_values[i]); | |
75a70cf9 | 1259 | gsi_insert_before (gsi, assign, GSI_SAME_STMT); |
f6ac75a7 | 1260 | update_stmt (assign); |
a347af29 | 1261 | } |
1262 | return assign; | |
1263 | } | |
1264 | ||
1265 | /* Deletes the unused bbs and edges that now contain the switch statement and | |
1266 | its empty branch bbs. BBD is the now dead BB containing the original switch | |
1267 | statement, FINAL is the last BB of the converted switch statement (in terms | |
1268 | of succession). */ | |
1269 | ||
1270 | static void | |
c66f9851 | 1271 | prune_bbs (basic_block bbd, basic_block final, basic_block default_bb) |
a347af29 | 1272 | { |
1273 | edge_iterator ei; | |
1274 | edge e; | |
1275 | ||
1276 | for (ei = ei_start (bbd->succs); (e = ei_safe_edge (ei)); ) | |
1277 | { | |
1278 | basic_block bb; | |
1279 | bb = e->dest; | |
1280 | remove_edge (e); | |
c66f9851 | 1281 | if (bb != final && bb != default_bb) |
a347af29 | 1282 | delete_basic_block (bb); |
1283 | } | |
1284 | delete_basic_block (bbd); | |
1285 | } | |
1286 | ||
1287 | /* Add values to phi nodes in final_bb for the two new edges. E1F is the edge | |
1288 | from the basic block loading values from an array and E2F from the basic | |
1289 | block loading default values. BBF is the last switch basic block (see the | |
1290 | bbf description in the comment below). */ | |
1291 | ||
1292 | static void | |
5d459527 | 1293 | fix_phi_nodes (edge e1f, edge e2f, basic_block bbf, |
1294 | struct switch_conv_info *info) | |
a347af29 | 1295 | { |
1a91d914 | 1296 | gphi_iterator gsi; |
a347af29 | 1297 | int i; |
1298 | ||
75a70cf9 | 1299 | for (gsi = gsi_start_phis (bbf), i = 0; |
c66f9851 | 1300 | !gsi_end_p (gsi); gsi_next (&gsi)) |
a347af29 | 1301 | { |
1a91d914 | 1302 | gphi *phi = gsi.phi (); |
c66f9851 | 1303 | tree inbound, outbound; |
1304 | if (virtual_operand_p (gimple_phi_result (phi))) | |
7992e6b5 | 1305 | inbound = outbound = info->target_vop; |
c66f9851 | 1306 | else |
1307 | { | |
1308 | inbound = info->target_inbound_names[i]; | |
1309 | outbound = info->target_outbound_names[i++]; | |
1310 | } | |
1311 | add_phi_arg (phi, inbound, e1f, UNKNOWN_LOCATION); | |
1312 | if (!info->default_case_nonstandard) | |
1313 | add_phi_arg (phi, outbound, e2f, UNKNOWN_LOCATION); | |
a347af29 | 1314 | } |
a347af29 | 1315 | } |
1316 | ||
1317 | /* Creates a check whether the switch expression value actually falls into the | |
1318 | range given by all the cases. If it does not, the temporaries are loaded | |
1319 | with default values instead. SWTCH is the switch statement being converted. | |
1320 | ||
1321 | bb0 is the bb with the switch statement, however, we'll end it with a | |
1322 | condition instead. | |
1323 | ||
1324 | bb1 is the bb to be used when the range check went ok. It is derived from | |
1325 | the switch BB | |
1326 | ||
1327 | bb2 is the bb taken when the expression evaluated outside of the range | |
1328 | covered by the created arrays. It is populated by loads of default | |
1329 | values. | |
1330 | ||
1331 | bbF is a fall through for both bb1 and bb2 and contains exactly what | |
1332 | originally followed the switch statement. | |
1333 | ||
1334 | bbD contains the switch statement (in the end). It is unreachable but we | |
1335 | still need to strip off its edges. | |
1336 | */ | |
1337 | ||
1338 | static void | |
1a91d914 | 1339 | gen_inbound_check (gswitch *swtch, struct switch_conv_info *info) |
a347af29 | 1340 | { |
e60a6f7b | 1341 | tree label_decl1 = create_artificial_label (UNKNOWN_LOCATION); |
1342 | tree label_decl2 = create_artificial_label (UNKNOWN_LOCATION); | |
1343 | tree label_decl3 = create_artificial_label (UNKNOWN_LOCATION); | |
1a91d914 | 1344 | glabel *label1, *label2, *label3; |
8853d378 | 1345 | tree utype, tidx; |
a347af29 | 1346 | tree bound; |
1347 | ||
1a91d914 | 1348 | gcond *cond_stmt; |
a347af29 | 1349 | |
c66f9851 | 1350 | gassign *last_assign = NULL; |
75a70cf9 | 1351 | gimple_stmt_iterator gsi; |
a347af29 | 1352 | basic_block bb0, bb1, bb2, bbf, bbd; |
c66f9851 | 1353 | edge e01 = NULL, e02, e21, e1d, e1f, e2f; |
389dd41b | 1354 | location_t loc = gimple_location (swtch); |
a347af29 | 1355 | |
5d459527 | 1356 | gcc_assert (info->default_values); |
6da0d726 | 1357 | |
75a70cf9 | 1358 | bb0 = gimple_bb (swtch); |
a347af29 | 1359 | |
5d459527 | 1360 | tidx = gimple_assign_lhs (info->arr_ref_first); |
8853d378 | 1361 | utype = TREE_TYPE (tidx); |
1763aab8 | 1362 | |
a347af29 | 1363 | /* (end of) block 0 */ |
5d459527 | 1364 | gsi = gsi_for_stmt (info->arr_ref_first); |
8853d378 | 1365 | gsi_next (&gsi); |
a347af29 | 1366 | |
5d459527 | 1367 | bound = fold_convert_loc (loc, utype, info->range_size); |
8853d378 | 1368 | cond_stmt = gimple_build_cond (LE_EXPR, tidx, bound, NULL_TREE, NULL_TREE); |
75a70cf9 | 1369 | gsi_insert_before (&gsi, cond_stmt, GSI_SAME_STMT); |
f6ac75a7 | 1370 | update_stmt (cond_stmt); |
a347af29 | 1371 | |
1372 | /* block 2 */ | |
c66f9851 | 1373 | if (!info->default_case_nonstandard) |
1374 | { | |
1375 | label2 = gimple_build_label (label_decl2); | |
1376 | gsi_insert_before (&gsi, label2, GSI_SAME_STMT); | |
1377 | last_assign = gen_def_assigns (&gsi, info); | |
1378 | } | |
a347af29 | 1379 | |
1380 | /* block 1 */ | |
75a70cf9 | 1381 | label1 = gimple_build_label (label_decl1); |
1382 | gsi_insert_before (&gsi, label1, GSI_SAME_STMT); | |
a347af29 | 1383 | |
1384 | /* block F */ | |
5d459527 | 1385 | gsi = gsi_start_bb (info->final_bb); |
75a70cf9 | 1386 | label3 = gimple_build_label (label_decl3); |
1387 | gsi_insert_before (&gsi, label3, GSI_SAME_STMT); | |
a347af29 | 1388 | |
1389 | /* cfg fix */ | |
75a70cf9 | 1390 | e02 = split_block (bb0, cond_stmt); |
a347af29 | 1391 | bb2 = e02->dest; |
1392 | ||
c66f9851 | 1393 | if (info->default_case_nonstandard) |
1394 | { | |
1395 | bb1 = bb2; | |
1396 | bb2 = info->default_bb; | |
1397 | e01 = e02; | |
1398 | e01->flags = EDGE_TRUE_VALUE; | |
1399 | e02 = make_edge (bb0, bb2, EDGE_FALSE_VALUE); | |
1400 | edge e_default = find_edge (bb1, bb2); | |
1401 | for (gphi_iterator gsi = gsi_start_phis (bb2); | |
1402 | !gsi_end_p (gsi); gsi_next (&gsi)) | |
1403 | { | |
1404 | gphi *phi = gsi.phi (); | |
1405 | tree arg = PHI_ARG_DEF_FROM_EDGE (phi, e_default); | |
1406 | add_phi_arg (phi, arg, e02, | |
1407 | gimple_phi_arg_location_from_edge (phi, e_default)); | |
1408 | } | |
1409 | /* Partially fix the dominator tree, if it is available. */ | |
1410 | if (dom_info_available_p (CDI_DOMINATORS)) | |
1411 | redirect_immediate_dominators (CDI_DOMINATORS, bb1, bb0); | |
1412 | } | |
1413 | else | |
1414 | { | |
1415 | e21 = split_block (bb2, last_assign); | |
1416 | bb1 = e21->dest; | |
1417 | remove_edge (e21); | |
1418 | } | |
a347af29 | 1419 | |
5d459527 | 1420 | e1d = split_block (bb1, info->arr_ref_last); |
a347af29 | 1421 | bbd = e1d->dest; |
1422 | remove_edge (e1d); | |
1423 | ||
1424 | /* flags and profiles of the edge for in-range values */ | |
c66f9851 | 1425 | if (!info->default_case_nonstandard) |
1426 | e01 = make_edge (bb0, bb1, EDGE_TRUE_VALUE); | |
5d459527 | 1427 | e01->probability = REG_BR_PROB_BASE - info->default_prob; |
1428 | e01->count = info->other_count; | |
a347af29 | 1429 | |
1430 | /* flags and profiles of the edge taking care of out-of-range values */ | |
1431 | e02->flags &= ~EDGE_FALLTHRU; | |
1432 | e02->flags |= EDGE_FALSE_VALUE; | |
5d459527 | 1433 | e02->probability = info->default_prob; |
1434 | e02->count = info->default_count; | |
a347af29 | 1435 | |
5d459527 | 1436 | bbf = info->final_bb; |
a347af29 | 1437 | |
1438 | e1f = make_edge (bb1, bbf, EDGE_FALLTHRU); | |
1439 | e1f->probability = REG_BR_PROB_BASE; | |
5d459527 | 1440 | e1f->count = info->other_count; |
a347af29 | 1441 | |
c66f9851 | 1442 | if (info->default_case_nonstandard) |
1443 | e2f = NULL; | |
1444 | else | |
1445 | { | |
1446 | e2f = make_edge (bb2, bbf, EDGE_FALLTHRU); | |
1447 | e2f->probability = REG_BR_PROB_BASE; | |
1448 | e2f->count = info->default_count; | |
1449 | } | |
a347af29 | 1450 | |
1451 | /* frequencies of the new BBs */ | |
1452 | bb1->frequency = EDGE_FREQUENCY (e01); | |
1453 | bb2->frequency = EDGE_FREQUENCY (e02); | |
c66f9851 | 1454 | if (!info->default_case_nonstandard) |
1455 | bbf->frequency = EDGE_FREQUENCY (e1f) + EDGE_FREQUENCY (e2f); | |
a347af29 | 1456 | |
6da0d726 | 1457 | /* Tidy blocks that have become unreachable. */ |
c66f9851 | 1458 | prune_bbs (bbd, info->final_bb, |
1459 | info->default_case_nonstandard ? info->default_bb : NULL); | |
a347af29 | 1460 | |
6da0d726 | 1461 | /* Fixup the PHI nodes in bbF. */ |
5d459527 | 1462 | fix_phi_nodes (e1f, e2f, bbf, info); |
a347af29 | 1463 | |
6da0d726 | 1464 | /* Fix the dominator tree, if it is available. */ |
1465 | if (dom_info_available_p (CDI_DOMINATORS)) | |
1466 | { | |
f1f41a6c | 1467 | vec<basic_block> bbs_to_fix_dom; |
6da0d726 | 1468 | |
1469 | set_immediate_dominator (CDI_DOMINATORS, bb1, bb0); | |
c66f9851 | 1470 | if (!info->default_case_nonstandard) |
1471 | set_immediate_dominator (CDI_DOMINATORS, bb2, bb0); | |
78b7a675 | 1472 | if (! get_immediate_dominator (CDI_DOMINATORS, bbf)) |
6da0d726 | 1473 | /* If bbD was the immediate dominator ... */ |
1474 | set_immediate_dominator (CDI_DOMINATORS, bbf, bb0); | |
1475 | ||
c66f9851 | 1476 | bbs_to_fix_dom.create (3 + (bb2 != bbf)); |
f1f41a6c | 1477 | bbs_to_fix_dom.quick_push (bb0); |
1478 | bbs_to_fix_dom.quick_push (bb1); | |
c66f9851 | 1479 | if (bb2 != bbf) |
1480 | bbs_to_fix_dom.quick_push (bb2); | |
f1f41a6c | 1481 | bbs_to_fix_dom.quick_push (bbf); |
6da0d726 | 1482 | |
1483 | iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true); | |
f1f41a6c | 1484 | bbs_to_fix_dom.release (); |
6da0d726 | 1485 | } |
a347af29 | 1486 | } |
1487 | ||
1488 | /* The following function is invoked on every switch statement (the current one | |
1489 | is given in SWTCH) and runs the individual phases of switch conversion on it | |
5d459527 | 1490 | one after another until one fails or the conversion is completed. |
1491 | Returns NULL on success, or a pointer to a string with the reason why the | |
1492 | conversion failed. */ | |
a347af29 | 1493 | |
5d459527 | 1494 | static const char * |
1a91d914 | 1495 | process_switch (gswitch *swtch) |
a347af29 | 1496 | { |
5d459527 | 1497 | struct switch_conv_info info; |
a347af29 | 1498 | |
b7d0690f | 1499 | /* Group case labels so that we get the right results from the heuristics |
1500 | that decide on the code generation approach for this switch. */ | |
1501 | group_case_labels_stmt (swtch); | |
1502 | ||
1503 | /* If this switch is now a degenerate case with only a default label, | |
1504 | there is nothing left for us to do. */ | |
1505 | if (gimple_switch_num_labels (swtch) < 2) | |
1506 | return "switch is a degenerate case"; | |
11f2f313 | 1507 | |
1508 | collect_switch_conv_info (swtch, &info); | |
1509 | ||
1510 | /* No error markers should reach here (they should be filtered out | |
1511 | during gimplification). */ | |
1512 | gcc_checking_assert (TREE_TYPE (info.index_expr) != error_mark_node); | |
1513 | ||
78b7a675 | 1514 | /* A switch on a constant should have been optimized in tree-cfg-cleanup. */ |
1515 | gcc_checking_assert (! TREE_CONSTANT (info.index_expr)); | |
11f2f313 | 1516 | |
78b7a675 | 1517 | if (info.uniq <= MAX_CASE_BIT_TESTS) |
11f2f313 | 1518 | { |
78b7a675 | 1519 | if (expand_switch_using_bit_tests_p (info.range_size, |
637a765f | 1520 | info.uniq, info.count, |
1521 | optimize_bb_for_speed_p | |
1522 | (gimple_bb (swtch)))) | |
78b7a675 | 1523 | { |
1524 | if (dump_file) | |
1525 | fputs (" expanding as bit test is preferable\n", dump_file); | |
bcf8a30c | 1526 | emit_case_bit_tests (swtch, info.index_expr, info.range_min, |
1527 | info.range_size, info.range_max); | |
b3083327 | 1528 | loops_state_set (LOOPS_NEED_FIXUP); |
78b7a675 | 1529 | return NULL; |
1530 | } | |
1531 | ||
1532 | if (info.uniq <= 2) | |
1533 | /* This will be expanded as a decision tree in stmt.c:expand_case. */ | |
1534 | return " expanding as jumps is preferable"; | |
11f2f313 | 1535 | } |
a347af29 | 1536 | |
78b7a675 | 1537 | /* If there is no common successor, we cannot do the transformation. */ |
1538 | if (! info.final_bb) | |
1539 | return "no common successor to all case label target blocks found"; | |
1540 | ||
a347af29 | 1541 | /* Check the case label values are within reasonable range: */ |
11f2f313 | 1542 | if (!check_range (&info)) |
5d459527 | 1543 | { |
1544 | gcc_assert (info.reason); | |
1545 | return info.reason; | |
1546 | } | |
a347af29 | 1547 | |
1548 | /* For all the cases, see whether they are empty, the assignments they | |
1549 | represent constant and so on... */ | |
11f2f313 | 1550 | if (! check_all_empty_except_final (&info)) |
df2813c5 | 1551 | { |
11f2f313 | 1552 | gcc_assert (info.reason); |
1553 | return info.reason; | |
df2813c5 | 1554 | } |
c66f9851 | 1555 | if (!check_final_bb (swtch, &info)) |
5d459527 | 1556 | { |
1557 | gcc_assert (info.reason); | |
1558 | return info.reason; | |
1559 | } | |
a347af29 | 1560 | |
1561 | /* At this point all checks have passed and we can proceed with the | |
1562 | transformation. */ | |
1563 | ||
5d459527 | 1564 | create_temp_arrays (&info); |
c66f9851 | 1565 | gather_default_values (info.default_case_nonstandard |
1566 | ? gimple_switch_label (swtch, 1) | |
1567 | : gimple_switch_default_label (swtch), &info); | |
5d459527 | 1568 | build_constructors (swtch, &info); |
a347af29 | 1569 | |
5d459527 | 1570 | build_arrays (swtch, &info); /* Build the static arrays and assignments. */ |
1571 | gen_inbound_check (swtch, &info); /* Build the bounds check. */ | |
a347af29 | 1572 | |
1573 | /* Cleanup: */ | |
5d459527 | 1574 | free_temp_arrays (&info); |
1575 | return NULL; | |
a347af29 | 1576 | } |
1577 | ||
1578 | /* The main function of the pass scans statements for switches and invokes | |
1579 | process_switch on them. */ | |
1580 | ||
65b0537f | 1581 | namespace { |
1582 | ||
1583 | const pass_data pass_data_convert_switch = | |
1584 | { | |
1585 | GIMPLE_PASS, /* type */ | |
1586 | "switchconv", /* name */ | |
1587 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 1588 | TV_TREE_SWITCH_CONVERSION, /* tv_id */ |
1589 | ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
1590 | 0, /* properties_provided */ | |
1591 | 0, /* properties_destroyed */ | |
1592 | 0, /* todo_flags_start */ | |
8b88439e | 1593 | TODO_update_ssa, /* todo_flags_finish */ |
65b0537f | 1594 | }; |
1595 | ||
1596 | class pass_convert_switch : public gimple_opt_pass | |
1597 | { | |
1598 | public: | |
1599 | pass_convert_switch (gcc::context *ctxt) | |
1600 | : gimple_opt_pass (pass_data_convert_switch, ctxt) | |
1601 | {} | |
1602 | ||
1603 | /* opt_pass methods: */ | |
1604 | virtual bool gate (function *) { return flag_tree_switch_conversion != 0; } | |
1605 | virtual unsigned int execute (function *); | |
1606 | ||
1607 | }; // class pass_convert_switch | |
1608 | ||
1609 | unsigned int | |
1610 | pass_convert_switch::execute (function *fun) | |
a347af29 | 1611 | { |
1612 | basic_block bb; | |
1613 | ||
65b0537f | 1614 | FOR_EACH_BB_FN (bb, fun) |
a347af29 | 1615 | { |
5d459527 | 1616 | const char *failure_reason; |
42acab1c | 1617 | gimple *stmt = last_stmt (bb); |
75a70cf9 | 1618 | if (stmt && gimple_code (stmt) == GIMPLE_SWITCH) |
a347af29 | 1619 | { |
a347af29 | 1620 | if (dump_file) |
1621 | { | |
75a70cf9 | 1622 | expanded_location loc = expand_location (gimple_location (stmt)); |
1623 | ||
a347af29 | 1624 | fprintf (dump_file, "beginning to process the following " |
1625 | "SWITCH statement (%s:%d) : ------- \n", | |
1626 | loc.file, loc.line); | |
75a70cf9 | 1627 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
609e7ca1 | 1628 | putc ('\n', dump_file); |
a347af29 | 1629 | } |
1630 | ||
1a91d914 | 1631 | failure_reason = process_switch (as_a <gswitch *> (stmt)); |
5d459527 | 1632 | if (! failure_reason) |
a347af29 | 1633 | { |
1634 | if (dump_file) | |
1635 | { | |
609e7ca1 | 1636 | fputs ("Switch converted\n", dump_file); |
1637 | fputs ("--------------------------------\n", dump_file); | |
a347af29 | 1638 | } |
78b7a675 | 1639 | |
1640 | /* Make no effort to update the post-dominator tree. It is actually not | |
1641 | that hard for the transformations we have performed, but it is not | |
1642 | supported by iterate_fix_dominators. */ | |
1643 | free_dominance_info (CDI_POST_DOMINATORS); | |
a347af29 | 1644 | } |
1645 | else | |
1646 | { | |
1647 | if (dump_file) | |
1648 | { | |
609e7ca1 | 1649 | fputs ("Bailing out - ", dump_file); |
5d459527 | 1650 | fputs (failure_reason, dump_file); |
1651 | fputs ("\n--------------------------------\n", dump_file); | |
a347af29 | 1652 | } |
1653 | } | |
1654 | } | |
1655 | } | |
1656 | ||
1657 | return 0; | |
1658 | } | |
1659 | ||
cbe8bda8 | 1660 | } // anon namespace |
1661 | ||
1662 | gimple_opt_pass * | |
1663 | make_pass_convert_switch (gcc::context *ctxt) | |
1664 | { | |
1665 | return new pass_convert_switch (ctxt); | |
1666 | } |