| File: | build/gcc/tree-tailcall.cc |
| Warning: | line 943, column 10 Although the value stored to 'orig_stmt' is used in the enclosing expression, the value is never actually read from 'orig_stmt' |
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| 1 | /* Tail call optimization on trees. |
| 2 | Copyright (C) 2003-2023 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GCC. |
| 5 | |
| 6 | GCC is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 3, or (at your option) |
| 9 | any later version. |
| 10 | |
| 11 | GCC is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GCC; see the file COPYING3. If not see |
| 18 | <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "config.h" |
| 21 | #include "system.h" |
| 22 | #include "coretypes.h" |
| 23 | #include "backend.h" |
| 24 | #include "rtl.h" |
| 25 | #include "tree.h" |
| 26 | #include "gimple.h" |
| 27 | #include "cfghooks.h" |
| 28 | #include "tree-pass.h" |
| 29 | #include "ssa.h" |
| 30 | #include "cgraph.h" |
| 31 | #include "gimple-pretty-print.h" |
| 32 | #include "fold-const.h" |
| 33 | #include "stor-layout.h" |
| 34 | #include "gimple-iterator.h" |
| 35 | #include "gimplify-me.h" |
| 36 | #include "tree-cfg.h" |
| 37 | #include "tree-into-ssa.h" |
| 38 | #include "tree-dfa.h" |
| 39 | #include "except.h" |
| 40 | #include "tree-eh.h" |
| 41 | #include "dbgcnt.h" |
| 42 | #include "cfgloop.h" |
| 43 | #include "common/common-target.h" |
| 44 | #include "ipa-utils.h" |
| 45 | #include "tree-ssa-live.h" |
| 46 | |
| 47 | /* The file implements the tail recursion elimination. It is also used to |
| 48 | analyze the tail calls in general, passing the results to the rtl level |
| 49 | where they are used for sibcall optimization. |
| 50 | |
| 51 | In addition to the standard tail recursion elimination, we handle the most |
| 52 | trivial cases of making the call tail recursive by creating accumulators. |
| 53 | For example the following function |
| 54 | |
| 55 | int sum (int n) |
| 56 | { |
| 57 | if (n > 0) |
| 58 | return n + sum (n - 1); |
| 59 | else |
| 60 | return 0; |
| 61 | } |
| 62 | |
| 63 | is transformed into |
| 64 | |
| 65 | int sum (int n) |
| 66 | { |
| 67 | int acc = 0; |
| 68 | |
| 69 | while (n > 0) |
| 70 | acc += n--; |
| 71 | |
| 72 | return acc; |
| 73 | } |
| 74 | |
| 75 | To do this, we maintain two accumulators (a_acc and m_acc) that indicate |
| 76 | when we reach the return x statement, we should return a_acc + x * m_acc |
| 77 | instead. They are initially initialized to 0 and 1, respectively, |
| 78 | so the semantics of the function is obviously preserved. If we are |
| 79 | guaranteed that the value of the accumulator never change, we |
| 80 | omit the accumulator. |
| 81 | |
| 82 | There are three cases how the function may exit. The first one is |
| 83 | handled in adjust_return_value, the other two in adjust_accumulator_values |
| 84 | (the second case is actually a special case of the third one and we |
| 85 | present it separately just for clarity): |
| 86 | |
| 87 | 1) Just return x, where x is not in any of the remaining special shapes. |
| 88 | We rewrite this to a gimple equivalent of return m_acc * x + a_acc. |
| 89 | |
| 90 | 2) return f (...), where f is the current function, is rewritten in a |
| 91 | classical tail-recursion elimination way, into assignment of arguments |
| 92 | and jump to the start of the function. Values of the accumulators |
| 93 | are unchanged. |
| 94 | |
| 95 | 3) return a + m * f(...), where a and m do not depend on call to f. |
| 96 | To preserve the semantics described before we want this to be rewritten |
| 97 | in such a way that we finally return |
| 98 | |
| 99 | a_acc + (a + m * f(...)) * m_acc = (a_acc + a * m_acc) + (m * m_acc) * f(...). |
| 100 | |
| 101 | I.e. we increase a_acc by a * m_acc, multiply m_acc by m and |
| 102 | eliminate the tail call to f. Special cases when the value is just |
| 103 | added or just multiplied are obtained by setting a = 0 or m = 1. |
| 104 | |
| 105 | TODO -- it is possible to do similar tricks for other operations. */ |
| 106 | |
| 107 | /* A structure that describes the tailcall. */ |
| 108 | |
| 109 | struct tailcall |
| 110 | { |
| 111 | /* The iterator pointing to the call statement. */ |
| 112 | gimple_stmt_iterator call_gsi; |
| 113 | |
| 114 | /* True if it is a call to the current function. */ |
| 115 | bool tail_recursion; |
| 116 | |
| 117 | /* The return value of the caller is mult * f + add, where f is the return |
| 118 | value of the call. */ |
| 119 | tree mult, add; |
| 120 | |
| 121 | /* Next tailcall in the chain. */ |
| 122 | struct tailcall *next; |
| 123 | }; |
| 124 | |
| 125 | /* The variables holding the value of multiplicative and additive |
| 126 | accumulator. */ |
| 127 | static tree m_acc, a_acc; |
| 128 | |
| 129 | /* Bitmap with a bit for each function parameter which is set to true if we |
| 130 | have to copy the parameter for conversion of tail-recursive calls. */ |
| 131 | |
| 132 | static bitmap tailr_arg_needs_copy; |
| 133 | |
| 134 | /* Returns false when the function is not suitable for tail call optimization |
| 135 | from some reason (e.g. if it takes variable number of arguments). */ |
| 136 | |
| 137 | static bool |
| 138 | suitable_for_tail_opt_p (void) |
| 139 | { |
| 140 | if (cfun(cfun + 0)->stdarg) |
| 141 | return false; |
| 142 | |
| 143 | return true; |
| 144 | } |
| 145 | |
| 146 | /* Returns false when the function is not suitable for tail call optimization |
| 147 | for some reason (e.g. if it takes variable number of arguments). |
| 148 | This test must pass in addition to suitable_for_tail_opt_p in order to make |
| 149 | tail call discovery happen. */ |
| 150 | |
| 151 | static bool |
| 152 | suitable_for_tail_call_opt_p (void) |
| 153 | { |
| 154 | tree param; |
| 155 | |
| 156 | /* alloca (until we have stack slot life analysis) inhibits |
| 157 | sibling call optimizations, but not tail recursion. */ |
| 158 | if (cfun(cfun + 0)->calls_alloca) |
| 159 | return false; |
| 160 | |
| 161 | /* If we are using sjlj exceptions, we may need to add a call to |
| 162 | _Unwind_SjLj_Unregister at exit of the function. Which means |
| 163 | that we cannot do any sibcall transformations. */ |
| 164 | if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ |
| 165 | && current_function_has_exception_handlers ()) |
| 166 | return false; |
| 167 | |
| 168 | /* Any function that calls setjmp might have longjmp called from |
| 169 | any called function. ??? We really should represent this |
| 170 | properly in the CFG so that this needn't be special cased. */ |
| 171 | if (cfun(cfun + 0)->calls_setjmp) |
| 172 | return false; |
| 173 | |
| 174 | /* Various targets don't handle tail calls correctly in functions |
| 175 | that call __builtin_eh_return. */ |
| 176 | if (cfun(cfun + 0)->calls_eh_return) |
| 177 | return false; |
| 178 | |
| 179 | /* ??? It is OK if the argument of a function is taken in some cases, |
| 180 | but not in all cases. See PR15387 and PR19616. Revisit for 4.1. */ |
| 181 | for (param = DECL_ARGUMENTS (current_function_decl)((tree_check ((current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 181, __FUNCTION__, (FUNCTION_DECL)))->function_decl.arguments ); |
| 182 | param; |
| 183 | param = DECL_CHAIN (param)(((contains_struct_check (((contains_struct_check ((param), ( TS_DECL_MINIMAL), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 183, __FUNCTION__))), (TS_COMMON), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 183, __FUNCTION__))->common.chain))) |
| 184 | if (TREE_ADDRESSABLE (param)((param)->base.addressable_flag)) |
| 185 | return false; |
| 186 | |
| 187 | return true; |
| 188 | } |
| 189 | |
| 190 | /* Checks whether the expression EXPR in stmt AT is independent of the |
| 191 | statement pointed to by GSI (in a sense that we already know EXPR's value |
| 192 | at GSI). We use the fact that we are only called from the chain of |
| 193 | basic blocks that have only single successor. Returns the expression |
| 194 | containing the value of EXPR at GSI. */ |
| 195 | |
| 196 | static tree |
| 197 | independent_of_stmt_p (tree expr, gimple *at, gimple_stmt_iterator gsi, |
| 198 | bitmap to_move) |
| 199 | { |
| 200 | basic_block bb, call_bb, at_bb; |
| 201 | edge e; |
| 202 | edge_iterator ei; |
| 203 | |
| 204 | if (is_gimple_min_invariant (expr)) |
| 205 | return expr; |
| 206 | |
| 207 | if (TREE_CODE (expr)((enum tree_code) (expr)->base.code) != SSA_NAME) |
| 208 | return NULL_TREE(tree) nullptr; |
| 209 | |
| 210 | if (bitmap_bit_p (to_move, SSA_NAME_VERSION (expr)(tree_check ((expr), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 210, __FUNCTION__, (SSA_NAME)))->base.u.version)) |
| 211 | return expr; |
| 212 | |
| 213 | /* Mark the blocks in the chain leading to the end. */ |
| 214 | at_bb = gimple_bb (at); |
| 215 | call_bb = gimple_bb (gsi_stmt (gsi)); |
| 216 | for (bb = call_bb; bb != at_bb; bb = single_succ (bb)) |
| 217 | bb->aux = &bb->aux; |
| 218 | bb->aux = &bb->aux; |
| 219 | |
| 220 | while (1) |
| 221 | { |
| 222 | at = SSA_NAME_DEF_STMT (expr)(tree_check ((expr), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 222, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt; |
| 223 | bb = gimple_bb (at); |
| 224 | |
| 225 | /* The default definition or defined before the chain. */ |
| 226 | if (!bb || !bb->aux) |
| 227 | break; |
| 228 | |
| 229 | if (bb == call_bb) |
| 230 | { |
| 231 | for (; !gsi_end_p (gsi); gsi_next (&gsi)) |
| 232 | if (gsi_stmt (gsi) == at) |
| 233 | break; |
| 234 | |
| 235 | if (!gsi_end_p (gsi)) |
| 236 | expr = NULL_TREE(tree) nullptr; |
| 237 | break; |
| 238 | } |
| 239 | |
| 240 | if (gimple_code (at) != GIMPLE_PHI) |
| 241 | { |
| 242 | expr = NULL_TREE(tree) nullptr; |
| 243 | break; |
| 244 | } |
| 245 | |
| 246 | FOR_EACH_EDGE (e, ei, bb->preds)for ((ei) = ei_start_1 (&((bb->preds))); ei_cond ((ei) , &(e)); ei_next (&(ei))) |
| 247 | if (e->src->aux) |
| 248 | break; |
| 249 | gcc_assert (e)((void)(!(e) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 249, __FUNCTION__), 0 : 0)); |
| 250 | |
| 251 | expr = PHI_ARG_DEF_FROM_EDGE (at, e)gimple_phi_arg_def (((at)), ((e)->dest_idx)); |
| 252 | if (TREE_CODE (expr)((enum tree_code) (expr)->base.code) != SSA_NAME) |
| 253 | { |
| 254 | /* The value is a constant. */ |
| 255 | break; |
| 256 | } |
| 257 | } |
| 258 | |
| 259 | /* Unmark the blocks. */ |
| 260 | for (bb = call_bb; bb != at_bb; bb = single_succ (bb)) |
| 261 | bb->aux = NULLnullptr; |
| 262 | bb->aux = NULLnullptr; |
| 263 | |
| 264 | return expr; |
| 265 | } |
| 266 | |
| 267 | enum par { FAIL, OK, TRY_MOVE }; |
| 268 | |
| 269 | /* Simulates the effect of an assignment STMT on the return value of the tail |
| 270 | recursive CALL passed in ASS_VAR. M and A are the multiplicative and the |
| 271 | additive factor for the real return value. */ |
| 272 | |
| 273 | static par |
| 274 | process_assignment (gassign *stmt, |
| 275 | gimple_stmt_iterator call, tree *m, |
| 276 | tree *a, tree *ass_var, bitmap to_move) |
| 277 | { |
| 278 | tree op0, op1 = NULL_TREE(tree) nullptr, non_ass_var = NULL_TREE(tree) nullptr; |
| 279 | tree dest = gimple_assign_lhs (stmt); |
| 280 | enum tree_code code = gimple_assign_rhs_code (stmt); |
| 281 | enum gimple_rhs_class rhs_class = get_gimple_rhs_class (code); |
| 282 | tree src_var = gimple_assign_rhs1 (stmt); |
| 283 | |
| 284 | /* See if this is a simple copy operation of an SSA name to the function |
| 285 | result. In that case we may have a simple tail call. Ignore type |
| 286 | conversions that can never produce extra code between the function |
| 287 | call and the function return. */ |
| 288 | if ((rhs_class == GIMPLE_SINGLE_RHS || gimple_assign_cast_p (stmt)) |
| 289 | && src_var == *ass_var) |
| 290 | { |
| 291 | /* Reject a tailcall if the type conversion might need |
| 292 | additional code. */ |
| 293 | if (gimple_assign_cast_p (stmt)) |
| 294 | { |
| 295 | if (TYPE_MODE (TREE_TYPE (dest))((((enum tree_code) ((tree_class_check ((((contains_struct_check ((dest), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 295, __FUNCTION__))->typed.type)), (tcc_type), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 295, __FUNCTION__)))->base.code) == VECTOR_TYPE) ? vector_type_mode (((contains_struct_check ((dest), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 295, __FUNCTION__))->typed.type)) : (((contains_struct_check ((dest), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 295, __FUNCTION__))->typed.type))->type_common.mode) != TYPE_MODE (TREE_TYPE (src_var))((((enum tree_code) ((tree_class_check ((((contains_struct_check ((src_var), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 295, __FUNCTION__))->typed.type)), (tcc_type), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 295, __FUNCTION__)))->base.code) == VECTOR_TYPE) ? vector_type_mode (((contains_struct_check ((src_var), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 295, __FUNCTION__))->typed.type)) : (((contains_struct_check ((src_var), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 295, __FUNCTION__))->typed.type))->type_common.mode)) |
| 296 | return FAIL; |
| 297 | |
| 298 | /* Even if the type modes are the same, if the precision of the |
| 299 | type is smaller than mode's precision, |
| 300 | reduce_to_bit_field_precision would generate additional code. */ |
| 301 | if (INTEGRAL_TYPE_P (TREE_TYPE (dest))(((enum tree_code) (((contains_struct_check ((dest), (TS_TYPED ), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 301, __FUNCTION__))->typed.type))->base.code) == ENUMERAL_TYPE || ((enum tree_code) (((contains_struct_check ((dest), (TS_TYPED ), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 301, __FUNCTION__))->typed.type))->base.code) == BOOLEAN_TYPE || ((enum tree_code) (((contains_struct_check ((dest), (TS_TYPED ), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 301, __FUNCTION__))->typed.type))->base.code) == INTEGER_TYPE ) |
| 302 | && !type_has_mode_precision_p (TREE_TYPE (dest)((contains_struct_check ((dest), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 302, __FUNCTION__))->typed.type))) |
| 303 | return FAIL; |
| 304 | } |
| 305 | |
| 306 | *ass_var = dest; |
| 307 | return OK; |
| 308 | } |
| 309 | |
| 310 | switch (rhs_class) |
| 311 | { |
| 312 | case GIMPLE_BINARY_RHS: |
| 313 | op1 = gimple_assign_rhs2 (stmt); |
| 314 | |
| 315 | /* Fall through. */ |
| 316 | |
| 317 | case GIMPLE_UNARY_RHS: |
| 318 | op0 = gimple_assign_rhs1 (stmt); |
| 319 | break; |
| 320 | |
| 321 | default: |
| 322 | return FAIL; |
| 323 | } |
| 324 | |
| 325 | /* Accumulator optimizations will reverse the order of operations. |
| 326 | We can only do that for floating-point types if we're assuming |
| 327 | that addition and multiplication are associative. */ |
| 328 | if (!flag_associative_mathglobal_options.x_flag_associative_math) |
| 329 | if (FLOAT_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl)))((((enum tree_code) (((contains_struct_check ((((tree_check ( (current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__))->typed.type))->base.code) == REAL_TYPE ) || ((((enum tree_code) (((contains_struct_check ((((tree_check ((current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__))->typed.type))->base.code) == COMPLEX_TYPE || (((enum tree_code) (((contains_struct_check ((((tree_check ((current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__))->typed.type))->base.code) == VECTOR_TYPE )) && (((enum tree_code) (((contains_struct_check ((( (contains_struct_check ((((tree_check ((current_function_decl ), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__))->typed.type)), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 329, __FUNCTION__))->typed.type))->base.code) == REAL_TYPE )))) |
| 330 | return FAIL; |
| 331 | |
| 332 | if (rhs_class == GIMPLE_UNARY_RHS |
| 333 | && op0 == *ass_var) |
| 334 | ; |
| 335 | else if (op0 == *ass_var |
| 336 | && (non_ass_var = independent_of_stmt_p (op1, stmt, call, |
| 337 | to_move))) |
| 338 | ; |
| 339 | else if (*ass_var |
| 340 | && op1 == *ass_var |
| 341 | && (non_ass_var = independent_of_stmt_p (op0, stmt, call, |
| 342 | to_move))) |
| 343 | ; |
| 344 | else |
| 345 | return TRY_MOVE; |
| 346 | |
| 347 | switch (code) |
| 348 | { |
| 349 | case PLUS_EXPR: |
| 350 | *a = non_ass_var; |
| 351 | *ass_var = dest; |
| 352 | return OK; |
| 353 | |
| 354 | case POINTER_PLUS_EXPR: |
| 355 | if (op0 != *ass_var) |
| 356 | return FAIL; |
| 357 | *a = non_ass_var; |
| 358 | *ass_var = dest; |
| 359 | return OK; |
| 360 | |
| 361 | case MULT_EXPR: |
| 362 | *m = non_ass_var; |
| 363 | *ass_var = dest; |
| 364 | return OK; |
| 365 | |
| 366 | case NEGATE_EXPR: |
| 367 | *m = build_minus_one_cst (TREE_TYPE (op0)((contains_struct_check ((op0), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 367, __FUNCTION__))->typed.type)); |
| 368 | *ass_var = dest; |
| 369 | return OK; |
| 370 | |
| 371 | case MINUS_EXPR: |
| 372 | if (*ass_var == op0) |
| 373 | *a = fold_build1 (NEGATE_EXPR, TREE_TYPE (non_ass_var), non_ass_var)fold_build1_loc (((location_t) 0), NEGATE_EXPR, ((contains_struct_check ((non_ass_var), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 373, __FUNCTION__))->typed.type), non_ass_var ); |
| 374 | else |
| 375 | { |
| 376 | *m = build_minus_one_cst (TREE_TYPE (non_ass_var)((contains_struct_check ((non_ass_var), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 376, __FUNCTION__))->typed.type)); |
| 377 | *a = fold_build1 (NEGATE_EXPR, TREE_TYPE (non_ass_var), non_ass_var)fold_build1_loc (((location_t) 0), NEGATE_EXPR, ((contains_struct_check ((non_ass_var), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 377, __FUNCTION__))->typed.type), non_ass_var ); |
| 378 | } |
| 379 | |
| 380 | *ass_var = dest; |
| 381 | return OK; |
| 382 | |
| 383 | default: |
| 384 | return FAIL; |
| 385 | } |
| 386 | } |
| 387 | |
| 388 | /* Propagate VAR through phis on edge E. */ |
| 389 | |
| 390 | static tree |
| 391 | propagate_through_phis (tree var, edge e) |
| 392 | { |
| 393 | basic_block dest = e->dest; |
| 394 | gphi_iterator gsi; |
| 395 | |
| 396 | for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 397 | { |
| 398 | gphi *phi = gsi.phi (); |
| 399 | if (PHI_ARG_DEF_FROM_EDGE (phi, e)gimple_phi_arg_def (((phi)), ((e)->dest_idx)) == var) |
| 400 | return PHI_RESULT (phi)get_def_from_ptr (gimple_phi_result_ptr (phi)); |
| 401 | } |
| 402 | return var; |
| 403 | } |
| 404 | |
| 405 | /* Argument for compute_live_vars/live_vars_at_stmt and what compute_live_vars |
| 406 | returns. Computed lazily, but just once for the function. */ |
| 407 | static live_vars_map *live_vars; |
| 408 | static vec<bitmap_head> live_vars_vec; |
| 409 | |
| 410 | /* Finds tailcalls falling into basic block BB. The list of found tailcalls is |
| 411 | added to the start of RET. */ |
| 412 | |
| 413 | static void |
| 414 | find_tail_calls (basic_block bb, struct tailcall **ret) |
| 415 | { |
| 416 | tree ass_var = NULL_TREE(tree) nullptr, ret_var, func, param; |
| 417 | gimple *stmt; |
| 418 | gcall *call = NULLnullptr; |
| 419 | gimple_stmt_iterator gsi, agsi; |
| 420 | bool tail_recursion; |
| 421 | struct tailcall *nw; |
| 422 | edge e; |
| 423 | tree m, a; |
| 424 | basic_block abb; |
| 425 | size_t idx; |
| 426 | tree var; |
| 427 | |
| 428 | if (!single_succ_p (bb)) |
| 429 | return; |
| 430 | |
| 431 | for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) |
| 432 | { |
| 433 | stmt = gsi_stmt (gsi); |
| 434 | |
| 435 | /* Ignore labels, returns, nops, clobbers and debug stmts. */ |
| 436 | if (gimple_code (stmt) == GIMPLE_LABEL |
| 437 | || gimple_code (stmt) == GIMPLE_RETURN |
| 438 | || gimple_code (stmt) == GIMPLE_NOP |
| 439 | || gimple_code (stmt) == GIMPLE_PREDICT |
| 440 | || gimple_clobber_p (stmt) |
| 441 | || is_gimple_debug (stmt)) |
| 442 | continue; |
| 443 | |
| 444 | /* Check for a call. */ |
| 445 | if (is_gimple_call (stmt)) |
| 446 | { |
| 447 | call = as_a <gcall *> (stmt); |
| 448 | ass_var = gimple_call_lhs (call); |
| 449 | break; |
| 450 | } |
| 451 | |
| 452 | /* Allow simple copies between local variables, even if they're |
| 453 | aggregates. */ |
| 454 | if (is_gimple_assign (stmt) |
| 455 | && auto_var_in_fn_p (gimple_assign_lhs (stmt), cfun(cfun + 0)->decl) |
| 456 | && auto_var_in_fn_p (gimple_assign_rhs1 (stmt), cfun(cfun + 0)->decl)) |
| 457 | continue; |
| 458 | |
| 459 | /* If the statement references memory or volatile operands, fail. */ |
| 460 | if (gimple_references_memory_p (stmt) |
| 461 | || gimple_has_volatile_ops (stmt)) |
| 462 | return; |
| 463 | } |
| 464 | |
| 465 | if (gsi_end_p (gsi)) |
| 466 | { |
| 467 | edge_iterator ei; |
| 468 | /* Recurse to the predecessors. */ |
| 469 | FOR_EACH_EDGE (e, ei, bb->preds)for ((ei) = ei_start_1 (&((bb->preds))); ei_cond ((ei) , &(e)); ei_next (&(ei))) |
| 470 | find_tail_calls (e->src, ret); |
| 471 | |
| 472 | return; |
| 473 | } |
| 474 | |
| 475 | /* If the LHS of our call is not just a simple register or local |
| 476 | variable, we can't transform this into a tail or sibling call. |
| 477 | This situation happens, in (e.g.) "*p = foo()" where foo returns a |
| 478 | struct. In this case we won't have a temporary here, but we need |
| 479 | to carry out the side effect anyway, so tailcall is impossible. |
| 480 | |
| 481 | ??? In some situations (when the struct is returned in memory via |
| 482 | invisible argument) we could deal with this, e.g. by passing 'p' |
| 483 | itself as that argument to foo, but it's too early to do this here, |
| 484 | and expand_call() will not handle it anyway. If it ever can, then |
| 485 | we need to revisit this here, to allow that situation. */ |
| 486 | if (ass_var |
| 487 | && !is_gimple_reg (ass_var) |
| 488 | && !auto_var_in_fn_p (ass_var, cfun(cfun + 0)->decl)) |
| 489 | return; |
| 490 | |
| 491 | /* If the call might throw an exception that wouldn't propagate out of |
| 492 | cfun, we can't transform to a tail or sibling call (82081). */ |
| 493 | if (stmt_could_throw_p (cfun(cfun + 0), stmt) |
| 494 | && !stmt_can_throw_external (cfun(cfun + 0), stmt)) |
| 495 | return; |
| 496 | |
| 497 | /* If the function returns a value, then at present, the tail call |
| 498 | must return the same type of value. There is conceptually a copy |
| 499 | between the object returned by the tail call candidate and the |
| 500 | object returned by CFUN itself. |
| 501 | |
| 502 | This means that if we have: |
| 503 | |
| 504 | lhs = f (&<retval>); // f reads from <retval> |
| 505 | // (lhs is usually also <retval>) |
| 506 | |
| 507 | there is a copy between the temporary object returned by f and lhs, |
| 508 | meaning that any use of <retval> in f occurs before the assignment |
| 509 | to lhs begins. Thus the <retval> that is live on entry to the call |
| 510 | to f is really an independent local variable V that happens to be |
| 511 | stored in the RESULT_DECL rather than a local VAR_DECL. |
| 512 | |
| 513 | Turning this into a tail call would remove the copy and make the |
| 514 | lifetimes of the return value and V overlap. The same applies to |
| 515 | tail recursion, since if f can read from <retval>, we have to assume |
| 516 | that CFUN might already have written to <retval> before the call. |
| 517 | |
| 518 | The problem doesn't apply when <retval> is passed by value, but that |
| 519 | isn't a case we handle anyway. */ |
| 520 | tree result_decl = DECL_RESULT (cfun->decl)((tree_check (((cfun + 0)->decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 520, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result ); |
| 521 | if (result_decl |
| 522 | && may_be_aliased (result_decl) |
| 523 | && ref_maybe_used_by_stmt_p (call, result_decl, false)) |
| 524 | return; |
| 525 | |
| 526 | /* We found the call, check whether it is suitable. */ |
| 527 | tail_recursion = false; |
| 528 | func = gimple_call_fndecl (call); |
| 529 | if (func |
| 530 | && !fndecl_built_in_p (func) |
| 531 | && recursive_call_p (current_function_decl, func)) |
| 532 | { |
| 533 | tree arg; |
| 534 | |
| 535 | for (param = DECL_ARGUMENTS (current_function_decl)((tree_check ((current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 535, __FUNCTION__, (FUNCTION_DECL)))->function_decl.arguments ), idx = 0; |
| 536 | param && idx < gimple_call_num_args (call); |
| 537 | param = DECL_CHAIN (param)(((contains_struct_check (((contains_struct_check ((param), ( TS_DECL_MINIMAL), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 537, __FUNCTION__))), (TS_COMMON), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 537, __FUNCTION__))->common.chain)), idx ++) |
| 538 | { |
| 539 | arg = gimple_call_arg (call, idx); |
| 540 | if (param != arg) |
| 541 | { |
| 542 | /* Make sure there are no problems with copying. The parameter |
| 543 | have a copyable type and the two arguments must have reasonably |
| 544 | equivalent types. The latter requirement could be relaxed if |
| 545 | we emitted a suitable type conversion statement. */ |
| 546 | if (!is_gimple_reg_type (TREE_TYPE (param)((contains_struct_check ((param), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 546, __FUNCTION__))->typed.type)) |
| 547 | || !useless_type_conversion_p (TREE_TYPE (param)((contains_struct_check ((param), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 547, __FUNCTION__))->typed.type), |
| 548 | TREE_TYPE (arg)((contains_struct_check ((arg), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 548, __FUNCTION__))->typed.type))) |
| 549 | break; |
| 550 | |
| 551 | /* The parameter should be a real operand, so that phi node |
| 552 | created for it at the start of the function has the meaning |
| 553 | of copying the value. This test implies is_gimple_reg_type |
| 554 | from the previous condition, however this one could be |
| 555 | relaxed by being more careful with copying the new value |
| 556 | of the parameter (emitting appropriate GIMPLE_ASSIGN and |
| 557 | updating the virtual operands). */ |
| 558 | if (!is_gimple_reg (param)) |
| 559 | break; |
| 560 | } |
| 561 | } |
| 562 | if (idx == gimple_call_num_args (call) && !param) |
| 563 | tail_recursion = true; |
| 564 | } |
| 565 | |
| 566 | /* Compute live vars if not computed yet. */ |
| 567 | if (live_vars == NULLnullptr) |
| 568 | { |
| 569 | unsigned int cnt = 0; |
| 570 | FOR_EACH_LOCAL_DECL (cfun, idx, var)for (idx = vec_safe_length (((cfun + 0))->local_decls) - 1 ; vec_safe_iterate ((((cfun + 0))->local_decls), (idx), & (var)); (idx)--) |
| 571 | if (VAR_P (var)(((enum tree_code) (var)->base.code) == VAR_DECL) |
| 572 | && auto_var_in_fn_p (var, cfun(cfun + 0)->decl) |
| 573 | && may_be_aliased (var)) |
| 574 | { |
| 575 | if (live_vars == NULLnullptr) |
| 576 | live_vars = new live_vars_map; |
| 577 | live_vars->put (DECL_UID (var)((contains_struct_check ((var), (TS_DECL_MINIMAL), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 577, __FUNCTION__))->decl_minimal.uid), cnt++); |
| 578 | } |
| 579 | if (live_vars) |
| 580 | live_vars_vec = compute_live_vars (cfun(cfun + 0), live_vars); |
| 581 | } |
| 582 | |
| 583 | /* Determine a bitmap of variables which are still in scope after the |
| 584 | call. */ |
| 585 | bitmap local_live_vars = NULLnullptr; |
| 586 | if (live_vars) |
| 587 | local_live_vars = live_vars_at_stmt (live_vars_vec, live_vars, call); |
| 588 | |
| 589 | /* Make sure the tail invocation of this function does not indirectly |
| 590 | refer to local variables. (Passing variables directly by value |
| 591 | is OK.) */ |
| 592 | FOR_EACH_LOCAL_DECL (cfun, idx, var)for (idx = vec_safe_length (((cfun + 0))->local_decls) - 1 ; vec_safe_iterate ((((cfun + 0))->local_decls), (idx), & (var)); (idx)--) |
| 593 | { |
| 594 | if (TREE_CODE (var)((enum tree_code) (var)->base.code) != PARM_DECL |
| 595 | && auto_var_in_fn_p (var, cfun(cfun + 0)->decl) |
| 596 | && may_be_aliased (var) |
| 597 | && (ref_maybe_used_by_stmt_p (call, var, false) |
| 598 | || call_may_clobber_ref_p (call, var, false))) |
| 599 | { |
| 600 | if (!VAR_P (var)(((enum tree_code) (var)->base.code) == VAR_DECL)) |
| 601 | { |
| 602 | if (local_live_vars) |
| 603 | BITMAP_FREE (local_live_vars)((void) (bitmap_obstack_free ((bitmap) local_live_vars), (local_live_vars ) = (bitmap) nullptr)); |
| 604 | return; |
| 605 | } |
| 606 | else |
| 607 | { |
| 608 | unsigned int *v = live_vars->get (DECL_UID (var)((contains_struct_check ((var), (TS_DECL_MINIMAL), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 608, __FUNCTION__))->decl_minimal.uid)); |
| 609 | if (bitmap_bit_p (local_live_vars, *v)) |
| 610 | { |
| 611 | BITMAP_FREE (local_live_vars)((void) (bitmap_obstack_free ((bitmap) local_live_vars), (local_live_vars ) = (bitmap) nullptr)); |
| 612 | return; |
| 613 | } |
| 614 | } |
| 615 | } |
| 616 | } |
| 617 | |
| 618 | if (local_live_vars) |
| 619 | BITMAP_FREE (local_live_vars)((void) (bitmap_obstack_free ((bitmap) local_live_vars), (local_live_vars ) = (bitmap) nullptr)); |
| 620 | |
| 621 | /* Now check the statements after the call. None of them has virtual |
| 622 | operands, so they may only depend on the call through its return |
| 623 | value. The return value should also be dependent on each of them, |
| 624 | since we are running after dce. */ |
| 625 | m = NULL_TREE(tree) nullptr; |
| 626 | a = NULL_TREE(tree) nullptr; |
| 627 | auto_bitmap to_move_defs; |
| 628 | auto_vec<gimple *> to_move_stmts; |
| 629 | |
| 630 | abb = bb; |
| 631 | agsi = gsi; |
| 632 | while (1) |
| 633 | { |
| 634 | tree tmp_a = NULL_TREE(tree) nullptr; |
| 635 | tree tmp_m = NULL_TREE(tree) nullptr; |
| 636 | gsi_next (&agsi); |
| 637 | |
| 638 | while (gsi_end_p (agsi)) |
| 639 | { |
| 640 | ass_var = propagate_through_phis (ass_var, single_succ_edge (abb)); |
| 641 | abb = single_succ (abb); |
| 642 | agsi = gsi_start_bb (abb); |
| 643 | } |
| 644 | |
| 645 | stmt = gsi_stmt (agsi); |
| 646 | if (gimple_code (stmt) == GIMPLE_RETURN) |
| 647 | break; |
| 648 | |
| 649 | if (gimple_code (stmt) == GIMPLE_LABEL |
| 650 | || gimple_code (stmt) == GIMPLE_NOP |
| 651 | || gimple_code (stmt) == GIMPLE_PREDICT |
| 652 | || gimple_clobber_p (stmt) |
| 653 | || is_gimple_debug (stmt)) |
| 654 | continue; |
| 655 | |
| 656 | if (gimple_code (stmt) != GIMPLE_ASSIGN) |
| 657 | return; |
| 658 | |
| 659 | /* This is a gimple assign. */ |
| 660 | par ret = process_assignment (as_a <gassign *> (stmt), gsi, |
| 661 | &tmp_m, &tmp_a, &ass_var, to_move_defs); |
| 662 | if (ret == FAIL) |
| 663 | return; |
| 664 | else if (ret == TRY_MOVE) |
| 665 | { |
| 666 | if (! tail_recursion) |
| 667 | return; |
| 668 | /* Do not deal with checking dominance, the real fix is to |
| 669 | do path isolation for the transform phase anyway, removing |
| 670 | the need to compute the accumulators with new stmts. */ |
| 671 | if (abb != bb) |
| 672 | return; |
| 673 | for (unsigned opno = 1; opno < gimple_num_ops (stmt); ++opno) |
| 674 | { |
| 675 | tree op = gimple_op (stmt, opno); |
| 676 | if (independent_of_stmt_p (op, stmt, gsi, to_move_defs) != op) |
| 677 | return; |
| 678 | } |
| 679 | bitmap_set_bit (to_move_defs, |
| 680 | SSA_NAME_VERSION (gimple_assign_lhs (stmt))(tree_check ((gimple_assign_lhs (stmt)), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 680, __FUNCTION__, (SSA_NAME)))->base.u.version); |
| 681 | to_move_stmts.safe_push (stmt); |
| 682 | continue; |
| 683 | } |
| 684 | |
| 685 | if (tmp_a) |
| 686 | { |
| 687 | tree type = TREE_TYPE (tmp_a)((contains_struct_check ((tmp_a), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 687, __FUNCTION__))->typed.type); |
| 688 | if (a) |
| 689 | a = fold_build2 (PLUS_EXPR, type, fold_convert (type, a), tmp_a)fold_build2_loc (((location_t) 0), PLUS_EXPR, type, fold_convert_loc (((location_t) 0), type, a), tmp_a ); |
| 690 | else |
| 691 | a = tmp_a; |
| 692 | } |
| 693 | if (tmp_m) |
| 694 | { |
| 695 | tree type = TREE_TYPE (tmp_m)((contains_struct_check ((tmp_m), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 695, __FUNCTION__))->typed.type); |
| 696 | if (m) |
| 697 | m = fold_build2 (MULT_EXPR, type, fold_convert (type, m), tmp_m)fold_build2_loc (((location_t) 0), MULT_EXPR, type, fold_convert_loc (((location_t) 0), type, m), tmp_m ); |
| 698 | else |
| 699 | m = tmp_m; |
| 700 | |
| 701 | if (a) |
| 702 | a = fold_build2 (MULT_EXPR, type, fold_convert (type, a), tmp_m)fold_build2_loc (((location_t) 0), MULT_EXPR, type, fold_convert_loc (((location_t) 0), type, a), tmp_m ); |
| 703 | } |
| 704 | } |
| 705 | |
| 706 | /* See if this is a tail call we can handle. */ |
| 707 | ret_var = gimple_return_retval (as_a <greturn *> (stmt)); |
| 708 | |
| 709 | /* We may proceed if there either is no return value, or the return value |
| 710 | is identical to the call's return or if the return decl is an empty type |
| 711 | variable and the call's return was not assigned. */ |
| 712 | if (ret_var |
| 713 | && (ret_var != ass_var |
| 714 | && !(is_empty_type (TREE_TYPE (ret_var)((contains_struct_check ((ret_var), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 714, __FUNCTION__))->typed.type)) && !ass_var))) |
| 715 | return; |
| 716 | |
| 717 | /* If this is not a tail recursive call, we cannot handle addends or |
| 718 | multiplicands. */ |
| 719 | if (!tail_recursion && (m || a)) |
| 720 | return; |
| 721 | |
| 722 | /* For pointers only allow additions. */ |
| 723 | if (m && POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl)))(((enum tree_code) (((contains_struct_check ((((tree_check (( current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 723, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 723, __FUNCTION__))->typed.type))->base.code) == POINTER_TYPE || ((enum tree_code) (((contains_struct_check ((((tree_check ((current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 723, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 723, __FUNCTION__))->typed.type))->base.code) == REFERENCE_TYPE )) |
| 724 | return; |
| 725 | |
| 726 | /* Move queued defs. */ |
| 727 | if (tail_recursion) |
| 728 | { |
| 729 | unsigned i; |
| 730 | FOR_EACH_VEC_ELT (to_move_stmts, i, stmt)for (i = 0; (to_move_stmts).iterate ((i), &(stmt)); ++(i) ) |
| 731 | { |
| 732 | gimple_stmt_iterator mgsi = gsi_for_stmt (stmt); |
| 733 | gsi_move_before (&mgsi, &gsi); |
| 734 | } |
| 735 | if (!tailr_arg_needs_copy) |
| 736 | tailr_arg_needs_copy = BITMAP_ALLOCbitmap_alloc (NULLnullptr); |
| 737 | for (param = DECL_ARGUMENTS (current_function_decl)((tree_check ((current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 737, __FUNCTION__, (FUNCTION_DECL)))->function_decl.arguments ), idx = 0; |
| 738 | param; |
| 739 | param = DECL_CHAIN (param)(((contains_struct_check (((contains_struct_check ((param), ( TS_DECL_MINIMAL), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 739, __FUNCTION__))), (TS_COMMON), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 739, __FUNCTION__))->common.chain)), idx++) |
| 740 | { |
| 741 | tree ddef, arg = gimple_call_arg (call, idx); |
| 742 | if (is_gimple_reg (param) |
| 743 | && (ddef = ssa_default_def (cfun(cfun + 0), param)) |
| 744 | && (arg != ddef)) |
| 745 | bitmap_set_bit (tailr_arg_needs_copy, idx); |
| 746 | } |
| 747 | } |
| 748 | |
| 749 | nw = XNEW (struct tailcall)((struct tailcall *) xmalloc (sizeof (struct tailcall))); |
| 750 | |
| 751 | nw->call_gsi = gsi; |
| 752 | |
| 753 | nw->tail_recursion = tail_recursion; |
| 754 | |
| 755 | nw->mult = m; |
| 756 | nw->add = a; |
| 757 | |
| 758 | nw->next = *ret; |
| 759 | *ret = nw; |
| 760 | } |
| 761 | |
| 762 | /* Helper to insert PHI_ARGH to the phi of VAR in the destination of edge E. */ |
| 763 | |
| 764 | static void |
| 765 | add_successor_phi_arg (edge e, tree var, tree phi_arg) |
| 766 | { |
| 767 | gphi_iterator gsi; |
| 768 | |
| 769 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 770 | if (PHI_RESULT (gsi.phi ())get_def_from_ptr (gimple_phi_result_ptr (gsi.phi ())) == var) |
| 771 | break; |
| 772 | |
| 773 | gcc_assert (!gsi_end_p (gsi))((void)(!(!gsi_end_p (gsi)) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 773, __FUNCTION__), 0 : 0)); |
| 774 | add_phi_arg (gsi.phi (), phi_arg, e, UNKNOWN_LOCATION((location_t) 0)); |
| 775 | } |
| 776 | |
| 777 | /* Creates a GIMPLE statement which computes the operation specified by |
| 778 | CODE, ACC and OP1 to a new variable with name LABEL and inserts the |
| 779 | statement in the position specified by GSI. Returns the |
| 780 | tree node of the statement's result. */ |
| 781 | |
| 782 | static tree |
| 783 | adjust_return_value_with_ops (enum tree_code code, const char *label, |
| 784 | tree acc, tree op1, gimple_stmt_iterator gsi) |
| 785 | { |
| 786 | |
| 787 | tree ret_type = TREE_TYPE (DECL_RESULT (current_function_decl))((contains_struct_check ((((tree_check ((current_function_decl ), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 787, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 787, __FUNCTION__))->typed.type); |
| 788 | tree result = make_temp_ssa_name (ret_type, NULLnullptr, label); |
| 789 | gassign *stmt; |
| 790 | |
| 791 | if (POINTER_TYPE_P (ret_type)(((enum tree_code) (ret_type)->base.code) == POINTER_TYPE || ((enum tree_code) (ret_type)->base.code) == REFERENCE_TYPE )) |
| 792 | { |
| 793 | gcc_assert (code == PLUS_EXPR && TREE_TYPE (acc) == sizetype)((void)(!(code == PLUS_EXPR && ((contains_struct_check ((acc), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 793, __FUNCTION__))->typed.type) == sizetype_tab[(int) stk_sizetype ]) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 793, __FUNCTION__), 0 : 0)); |
| 794 | code = POINTER_PLUS_EXPR; |
| 795 | } |
| 796 | if (types_compatible_p (TREE_TYPE (acc)((contains_struct_check ((acc), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 796, __FUNCTION__))->typed.type), TREE_TYPE (op1)((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 796, __FUNCTION__))->typed.type)) |
| 797 | && code != POINTER_PLUS_EXPR) |
| 798 | stmt = gimple_build_assign (result, code, acc, op1); |
| 799 | else |
| 800 | { |
| 801 | tree tem; |
| 802 | if (code == POINTER_PLUS_EXPR) |
| 803 | tem = fold_build2 (code, TREE_TYPE (op1), op1, acc)fold_build2_loc (((location_t) 0), code, ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 803, __FUNCTION__))->typed.type), op1, acc ); |
| 804 | else |
| 805 | tem = fold_build2 (code, TREE_TYPE (op1),fold_build2_loc (((location_t) 0), code, ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 805, __FUNCTION__))->typed.type), fold_convert_loc (((location_t ) 0), ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 806, __FUNCTION__))->typed.type), acc), op1 ) |
| 806 | fold_convert (TREE_TYPE (op1), acc), op1)fold_build2_loc (((location_t) 0), code, ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 805, __FUNCTION__))->typed.type), fold_convert_loc (((location_t ) 0), ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 806, __FUNCTION__))->typed.type), acc), op1 ); |
| 807 | tree rhs = fold_convert (ret_type, tem)fold_convert_loc (((location_t) 0), ret_type, tem); |
| 808 | rhs = force_gimple_operand_gsi (&gsi, rhs, |
| 809 | false, NULLnullptr, true, GSI_SAME_STMT); |
| 810 | stmt = gimple_build_assign (result, rhs); |
| 811 | } |
| 812 | |
| 813 | gsi_insert_before (&gsi, stmt, GSI_NEW_STMT); |
| 814 | return result; |
| 815 | } |
| 816 | |
| 817 | /* Creates a new GIMPLE statement that adjusts the value of accumulator ACC by |
| 818 | the computation specified by CODE and OP1 and insert the statement |
| 819 | at the position specified by GSI as a new statement. Returns new SSA name |
| 820 | of updated accumulator. */ |
| 821 | |
| 822 | static tree |
| 823 | update_accumulator_with_ops (enum tree_code code, tree acc, tree op1, |
| 824 | gimple_stmt_iterator gsi) |
| 825 | { |
| 826 | gassign *stmt; |
| 827 | tree var = copy_ssa_name (acc); |
| 828 | if (types_compatible_p (TREE_TYPE (acc)((contains_struct_check ((acc), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 828, __FUNCTION__))->typed.type), TREE_TYPE (op1)((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 828, __FUNCTION__))->typed.type))) |
| 829 | stmt = gimple_build_assign (var, code, acc, op1); |
| 830 | else |
| 831 | { |
| 832 | tree rhs = fold_convert (TREE_TYPE (acc),fold_convert_loc (((location_t) 0), ((contains_struct_check ( (acc), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 832, __FUNCTION__))->typed.type), fold_build2_loc (((location_t ) 0), code, ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 834, __FUNCTION__))->typed.type), fold_convert_loc (((location_t ) 0), ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 835, __FUNCTION__))->typed.type), acc), op1 )) |
| 833 | fold_build2 (code,fold_convert_loc (((location_t) 0), ((contains_struct_check ( (acc), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 832, __FUNCTION__))->typed.type), fold_build2_loc (((location_t ) 0), code, ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 834, __FUNCTION__))->typed.type), fold_convert_loc (((location_t ) 0), ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 835, __FUNCTION__))->typed.type), acc), op1 )) |
| 834 | TREE_TYPE (op1),fold_convert_loc (((location_t) 0), ((contains_struct_check ( (acc), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 832, __FUNCTION__))->typed.type), fold_build2_loc (((location_t ) 0), code, ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 834, __FUNCTION__))->typed.type), fold_convert_loc (((location_t ) 0), ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 835, __FUNCTION__))->typed.type), acc), op1 )) |
| 835 | fold_convert (TREE_TYPE (op1), acc),fold_convert_loc (((location_t) 0), ((contains_struct_check ( (acc), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 832, __FUNCTION__))->typed.type), fold_build2_loc (((location_t ) 0), code, ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 834, __FUNCTION__))->typed.type), fold_convert_loc (((location_t ) 0), ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 835, __FUNCTION__))->typed.type), acc), op1 )) |
| 836 | op1))fold_convert_loc (((location_t) 0), ((contains_struct_check ( (acc), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 832, __FUNCTION__))->typed.type), fold_build2_loc (((location_t ) 0), code, ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 834, __FUNCTION__))->typed.type), fold_convert_loc (((location_t ) 0), ((contains_struct_check ((op1), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 835, __FUNCTION__))->typed.type), acc), op1 )); |
| 837 | rhs = force_gimple_operand_gsi (&gsi, rhs, |
| 838 | false, NULLnullptr, false, GSI_CONTINUE_LINKING); |
| 839 | stmt = gimple_build_assign (var, rhs); |
| 840 | } |
| 841 | gsi_insert_after (&gsi, stmt, GSI_NEW_STMT); |
| 842 | return var; |
| 843 | } |
| 844 | |
| 845 | /* Adjust the accumulator values according to A and M after GSI, and update |
| 846 | the phi nodes on edge BACK. */ |
| 847 | |
| 848 | static void |
| 849 | adjust_accumulator_values (gimple_stmt_iterator gsi, tree m, tree a, edge back) |
| 850 | { |
| 851 | tree var, a_acc_arg, m_acc_arg; |
| 852 | |
| 853 | if (m) |
| 854 | m = force_gimple_operand_gsi (&gsi, m, true, NULLnullptr, true, GSI_SAME_STMT); |
| 855 | if (a) |
| 856 | a = force_gimple_operand_gsi (&gsi, a, true, NULLnullptr, true, GSI_SAME_STMT); |
| 857 | |
| 858 | a_acc_arg = a_acc; |
| 859 | m_acc_arg = m_acc; |
| 860 | if (a) |
| 861 | { |
| 862 | if (m_acc) |
| 863 | { |
| 864 | if (integer_onep (a)) |
| 865 | var = m_acc; |
| 866 | else |
| 867 | var = adjust_return_value_with_ops (MULT_EXPR, "acc_tmp", m_acc, |
| 868 | a, gsi); |
| 869 | } |
| 870 | else |
| 871 | var = a; |
| 872 | |
| 873 | a_acc_arg = update_accumulator_with_ops (PLUS_EXPR, a_acc, var, gsi); |
| 874 | } |
| 875 | |
| 876 | if (m) |
| 877 | m_acc_arg = update_accumulator_with_ops (MULT_EXPR, m_acc, m, gsi); |
| 878 | |
| 879 | if (a_acc) |
| 880 | add_successor_phi_arg (back, a_acc, a_acc_arg); |
| 881 | |
| 882 | if (m_acc) |
| 883 | add_successor_phi_arg (back, m_acc, m_acc_arg); |
| 884 | } |
| 885 | |
| 886 | /* Adjust value of the return at the end of BB according to M and A |
| 887 | accumulators. */ |
| 888 | |
| 889 | static void |
| 890 | adjust_return_value (basic_block bb, tree m, tree a) |
| 891 | { |
| 892 | tree retval; |
| 893 | greturn *ret_stmt = as_a <greturn *> (gimple_seq_last_stmt (bb_seq (bb))); |
| 894 | gimple_stmt_iterator gsi = gsi_last_bb (bb); |
| 895 | |
| 896 | gcc_assert (gimple_code (ret_stmt) == GIMPLE_RETURN)((void)(!(gimple_code (ret_stmt) == GIMPLE_RETURN) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 896, __FUNCTION__), 0 : 0)); |
| 897 | |
| 898 | retval = gimple_return_retval (ret_stmt); |
| 899 | if (!retval || retval == error_mark_nodeglobal_trees[TI_ERROR_MARK]) |
| 900 | return; |
| 901 | |
| 902 | if (m) |
| 903 | retval = adjust_return_value_with_ops (MULT_EXPR, "mul_tmp", m_acc, retval, |
| 904 | gsi); |
| 905 | if (a) |
| 906 | retval = adjust_return_value_with_ops (PLUS_EXPR, "acc_tmp", a_acc, retval, |
| 907 | gsi); |
| 908 | gimple_return_set_retval (ret_stmt, retval); |
| 909 | update_stmt (ret_stmt); |
| 910 | } |
| 911 | |
| 912 | /* Subtract COUNT and FREQUENCY from the basic block and it's |
| 913 | outgoing edge. */ |
| 914 | static void |
| 915 | decrease_profile (basic_block bb, profile_count count) |
| 916 | { |
| 917 | bb->count = bb->count - count; |
| 918 | if (!single_succ_p (bb)) |
| 919 | { |
| 920 | gcc_assert (!EDGE_COUNT (bb->succs))((void)(!(!vec_safe_length (bb->succs)) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 920, __FUNCTION__), 0 : 0)); |
| 921 | return; |
| 922 | } |
| 923 | } |
| 924 | |
| 925 | /* Eliminates tail call described by T. TMP_VARS is a list of |
| 926 | temporary variables used to copy the function arguments. |
| 927 | Allocates *NEW_LOOP if not already done and initializes it. */ |
| 928 | |
| 929 | static void |
| 930 | eliminate_tail_call (struct tailcall *t, class loop *&new_loop) |
| 931 | { |
| 932 | tree param, rslt; |
| 933 | gimple *stmt, *call; |
| 934 | tree arg; |
| 935 | size_t idx; |
| 936 | basic_block bb, first; |
| 937 | edge e; |
| 938 | gphi *phi; |
| 939 | gphi_iterator gpi; |
| 940 | gimple_stmt_iterator gsi; |
| 941 | gimple *orig_stmt; |
| 942 | |
| 943 | stmt = orig_stmt = gsi_stmt (t->call_gsi); |
Although the value stored to 'orig_stmt' is used in the enclosing expression, the value is never actually read from 'orig_stmt' | |
| 944 | bb = gsi_bb (t->call_gsi); |
| 945 | |
| 946 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 947 | { |
| 948 | fprintf (dump_file, "Eliminated tail recursion in bb %d : ", |
| 949 | bb->index); |
| 950 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
| 951 | fprintf (dump_file, "\n"); |
| 952 | } |
| 953 | |
| 954 | gcc_assert (is_gimple_call (stmt))((void)(!(is_gimple_call (stmt)) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 954, __FUNCTION__), 0 : 0)); |
| 955 | |
| 956 | first = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)(((cfun + 0))->cfg->x_entry_block_ptr)); |
| 957 | |
| 958 | /* Remove the code after call_gsi that will become unreachable. The |
| 959 | possibly unreachable code in other blocks is removed later in |
| 960 | cfg cleanup. */ |
| 961 | gsi = t->call_gsi; |
| 962 | gimple_stmt_iterator gsi2 = gsi_last_bb (gimple_bb (gsi_stmt (gsi))); |
| 963 | while (gsi_stmt (gsi2) != gsi_stmt (gsi)) |
| 964 | { |
| 965 | gimple *t = gsi_stmt (gsi2); |
| 966 | /* Do not remove the return statement, so that redirect_edge_and_branch |
| 967 | sees how the block ends. */ |
| 968 | if (gimple_code (t) != GIMPLE_RETURN) |
| 969 | { |
| 970 | gimple_stmt_iterator gsi3 = gsi2; |
| 971 | gsi_prev (&gsi2); |
| 972 | gsi_remove (&gsi3, true); |
| 973 | release_defs (t); |
| 974 | } |
| 975 | else |
| 976 | gsi_prev (&gsi2); |
| 977 | } |
| 978 | |
| 979 | /* Number of executions of function has reduced by the tailcall. */ |
| 980 | e = single_succ_edge (gsi_bb (t->call_gsi)); |
| 981 | |
| 982 | profile_count count = e->count (); |
| 983 | |
| 984 | /* When profile is inconsistent and the recursion edge is more frequent |
| 985 | than number of executions of functions, scale it down, so we do not end |
| 986 | up with 0 executions of entry block. */ |
| 987 | if (count >= ENTRY_BLOCK_PTR_FOR_FN (cfun)(((cfun + 0))->cfg->x_entry_block_ptr)->count) |
| 988 | count = ENTRY_BLOCK_PTR_FOR_FN (cfun)(((cfun + 0))->cfg->x_entry_block_ptr)->count.apply_scale (7, 8); |
| 989 | decrease_profile (EXIT_BLOCK_PTR_FOR_FN (cfun)(((cfun + 0))->cfg->x_exit_block_ptr), count); |
| 990 | decrease_profile (ENTRY_BLOCK_PTR_FOR_FN (cfun)(((cfun + 0))->cfg->x_entry_block_ptr), count); |
| 991 | if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)(((cfun + 0))->cfg->x_exit_block_ptr)) |
| 992 | decrease_profile (e->dest, count); |
| 993 | |
| 994 | /* Replace the call by a jump to the start of function. */ |
| 995 | e = redirect_edge_and_branch (single_succ_edge (gsi_bb (t->call_gsi)), |
| 996 | first); |
| 997 | gcc_assert (e)((void)(!(e) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 997, __FUNCTION__), 0 : 0)); |
| 998 | PENDING_STMT (e)((e)->insns.g) = NULLnullptr; |
| 999 | |
| 1000 | /* Add the new loop. */ |
| 1001 | if (!new_loop) |
| 1002 | { |
| 1003 | new_loop = alloc_loop (); |
| 1004 | new_loop->header = first; |
| 1005 | new_loop->finite_p = true; |
| 1006 | } |
| 1007 | else |
| 1008 | gcc_assert (new_loop->header == first)((void)(!(new_loop->header == first) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1008, __FUNCTION__), 0 : 0)); |
| 1009 | |
| 1010 | /* Add phi node entries for arguments. The ordering of the phi nodes should |
| 1011 | be the same as the ordering of the arguments. */ |
| 1012 | for (param = DECL_ARGUMENTS (current_function_decl)((tree_check ((current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1012, __FUNCTION__, (FUNCTION_DECL)))->function_decl.arguments ), |
| 1013 | idx = 0, gpi = gsi_start_phis (first); |
| 1014 | param; |
| 1015 | param = DECL_CHAIN (param)(((contains_struct_check (((contains_struct_check ((param), ( TS_DECL_MINIMAL), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1015, __FUNCTION__))), (TS_COMMON), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1015, __FUNCTION__))->common.chain)), idx++) |
| 1016 | { |
| 1017 | if (!bitmap_bit_p (tailr_arg_needs_copy, idx)) |
| 1018 | continue; |
| 1019 | |
| 1020 | arg = gimple_call_arg (stmt, idx); |
| 1021 | phi = gpi.phi (); |
| 1022 | gcc_assert (param == SSA_NAME_VAR (PHI_RESULT (phi)))((void)(!(param == ((tree_check ((get_def_from_ptr (gimple_phi_result_ptr (phi))), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1022, __FUNCTION__, (SSA_NAME)))->ssa_name.var == (tree) nullptr || ((enum tree_code) ((get_def_from_ptr (gimple_phi_result_ptr (phi)))->ssa_name.var)->base.code) == IDENTIFIER_NODE ? (tree) nullptr : (get_def_from_ptr (gimple_phi_result_ptr (phi )))->ssa_name.var)) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1022, __FUNCTION__), 0 : 0)); |
| 1023 | |
| 1024 | add_phi_arg (phi, arg, e, gimple_location (stmt)); |
| 1025 | gsi_next (&gpi); |
| 1026 | } |
| 1027 | |
| 1028 | /* Update the values of accumulators. */ |
| 1029 | adjust_accumulator_values (t->call_gsi, t->mult, t->add, e); |
| 1030 | |
| 1031 | call = gsi_stmt (t->call_gsi); |
| 1032 | rslt = gimple_call_lhs (call); |
| 1033 | if (rslt != NULL_TREE(tree) nullptr && TREE_CODE (rslt)((enum tree_code) (rslt)->base.code) == SSA_NAME) |
| 1034 | { |
| 1035 | /* Result of the call will no longer be defined. So adjust the |
| 1036 | SSA_NAME_DEF_STMT accordingly. */ |
| 1037 | SSA_NAME_DEF_STMT (rslt)(tree_check ((rslt), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1037, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt = gimple_build_nop (); |
| 1038 | } |
| 1039 | |
| 1040 | gsi_remove (&t->call_gsi, true); |
| 1041 | release_defs (call); |
| 1042 | } |
| 1043 | |
| 1044 | /* Optimizes the tailcall described by T. If OPT_TAILCALLS is true, also |
| 1045 | mark the tailcalls for the sibcall optimization. */ |
| 1046 | |
| 1047 | static bool |
| 1048 | optimize_tail_call (struct tailcall *t, bool opt_tailcalls, |
| 1049 | class loop *&new_loop) |
| 1050 | { |
| 1051 | if (t->tail_recursion) |
| 1052 | { |
| 1053 | eliminate_tail_call (t, new_loop); |
| 1054 | return true; |
| 1055 | } |
| 1056 | |
| 1057 | if (opt_tailcalls) |
| 1058 | { |
| 1059 | gcall *stmt = as_a <gcall *> (gsi_stmt (t->call_gsi)); |
| 1060 | |
| 1061 | gimple_call_set_tail (stmt, true); |
| 1062 | cfun(cfun + 0)->tail_call_marked = true; |
| 1063 | if (dump_file && (dump_flags & TDF_DETAILS)) |
| 1064 | { |
| 1065 | fprintf (dump_file, "Found tail call "); |
| 1066 | print_gimple_stmt (dump_file, stmt, 0, dump_flags); |
| 1067 | fprintf (dump_file, " in bb %i\n", (gsi_bb (t->call_gsi))->index); |
| 1068 | } |
| 1069 | } |
| 1070 | |
| 1071 | return false; |
| 1072 | } |
| 1073 | |
| 1074 | /* Creates a tail-call accumulator of the same type as the return type of the |
| 1075 | current function. LABEL is the name used to creating the temporary |
| 1076 | variable for the accumulator. The accumulator will be inserted in the |
| 1077 | phis of a basic block BB with single predecessor with an initial value |
| 1078 | INIT converted to the current function return type. */ |
| 1079 | |
| 1080 | static tree |
| 1081 | create_tailcall_accumulator (const char *label, basic_block bb, tree init) |
| 1082 | { |
| 1083 | tree ret_type = TREE_TYPE (DECL_RESULT (current_function_decl))((contains_struct_check ((((tree_check ((current_function_decl ), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1083, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1083, __FUNCTION__))->typed.type); |
| 1084 | if (POINTER_TYPE_P (ret_type)(((enum tree_code) (ret_type)->base.code) == POINTER_TYPE || ((enum tree_code) (ret_type)->base.code) == REFERENCE_TYPE )) |
| 1085 | ret_type = sizetypesizetype_tab[(int) stk_sizetype]; |
| 1086 | |
| 1087 | tree tmp = make_temp_ssa_name (ret_type, NULLnullptr, label); |
| 1088 | gphi *phi; |
| 1089 | |
| 1090 | phi = create_phi_node (tmp, bb); |
| 1091 | add_phi_arg (phi, init, single_pred_edge (bb), |
| 1092 | UNKNOWN_LOCATION((location_t) 0)); |
| 1093 | return PHI_RESULT (phi)get_def_from_ptr (gimple_phi_result_ptr (phi)); |
| 1094 | } |
| 1095 | |
| 1096 | /* Optimizes tail calls in the function, turning the tail recursion |
| 1097 | into iteration. */ |
| 1098 | |
| 1099 | static unsigned int |
| 1100 | tree_optimize_tail_calls_1 (bool opt_tailcalls) |
| 1101 | { |
| 1102 | edge e; |
| 1103 | bool phis_constructed = false; |
| 1104 | struct tailcall *tailcalls = NULLnullptr, *act, *next; |
| 1105 | bool changed = false; |
| 1106 | basic_block first = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)(((cfun + 0))->cfg->x_entry_block_ptr)); |
| 1107 | tree param; |
| 1108 | gimple *stmt; |
| 1109 | edge_iterator ei; |
| 1110 | |
| 1111 | if (!suitable_for_tail_opt_p ()) |
| 1112 | return 0; |
| 1113 | if (opt_tailcalls) |
| 1114 | opt_tailcalls = suitable_for_tail_call_opt_p (); |
| 1115 | |
| 1116 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)for ((ei) = ei_start_1 (&(((((cfun + 0))->cfg->x_exit_block_ptr )->preds))); ei_cond ((ei), &(e)); ei_next (&(ei)) ) |
| 1117 | { |
| 1118 | /* Only traverse the normal exits, i.e. those that end with return |
| 1119 | statement. */ |
| 1120 | stmt = last_stmt (e->src); |
| 1121 | |
| 1122 | if (stmt |
| 1123 | && gimple_code (stmt) == GIMPLE_RETURN) |
| 1124 | find_tail_calls (e->src, &tailcalls); |
| 1125 | } |
| 1126 | |
| 1127 | if (live_vars) |
| 1128 | { |
| 1129 | destroy_live_vars (live_vars_vec); |
| 1130 | delete live_vars; |
| 1131 | live_vars = NULLnullptr; |
| 1132 | } |
| 1133 | |
| 1134 | /* Construct the phi nodes and accumulators if necessary. */ |
| 1135 | a_acc = m_acc = NULL_TREE(tree) nullptr; |
| 1136 | for (act = tailcalls; act; act = act->next) |
| 1137 | { |
| 1138 | if (!act->tail_recursion) |
| 1139 | continue; |
| 1140 | |
| 1141 | if (!phis_constructed) |
| 1142 | { |
| 1143 | /* Ensure that there is only one predecessor of the block |
| 1144 | or if there are existing degenerate PHI nodes. */ |
| 1145 | if (!single_pred_p (first) |
| 1146 | || !gimple_seq_empty_p (phi_nodes (first))) |
| 1147 | first = |
| 1148 | split_edge (single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun)(((cfun + 0))->cfg->x_entry_block_ptr))); |
| 1149 | |
| 1150 | /* Copy the args if needed. */ |
| 1151 | unsigned idx; |
| 1152 | for (param = DECL_ARGUMENTS (current_function_decl)((tree_check ((current_function_decl), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1152, __FUNCTION__, (FUNCTION_DECL)))->function_decl.arguments ), idx = 0; |
| 1153 | param; |
| 1154 | param = DECL_CHAIN (param)(((contains_struct_check (((contains_struct_check ((param), ( TS_DECL_MINIMAL), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1154, __FUNCTION__))), (TS_COMMON), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1154, __FUNCTION__))->common.chain)), idx++) |
| 1155 | if (bitmap_bit_p (tailr_arg_needs_copy, idx)) |
| 1156 | { |
| 1157 | tree name = ssa_default_def (cfun(cfun + 0), param); |
| 1158 | tree new_name = make_ssa_name (param, SSA_NAME_DEF_STMT (name)(tree_check ((name), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1158, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt); |
| 1159 | gphi *phi; |
| 1160 | |
| 1161 | set_ssa_default_def (cfun(cfun + 0), param, new_name); |
| 1162 | phi = create_phi_node (name, first); |
| 1163 | add_phi_arg (phi, new_name, single_pred_edge (first), |
| 1164 | EXPR_LOCATION (param)((((param)) && ((tree_code_type_tmpl <0>::tree_code_type [(int) (((enum tree_code) ((param))->base.code))]) >= tcc_reference && (tree_code_type_tmpl <0>::tree_code_type[(int ) (((enum tree_code) ((param))->base.code))]) <= tcc_expression )) ? (param)->exp.locus : ((location_t) 0))); |
| 1165 | } |
| 1166 | phis_constructed = true; |
| 1167 | } |
| 1168 | tree ret_type = TREE_TYPE (DECL_RESULT (current_function_decl))((contains_struct_check ((((tree_check ((current_function_decl ), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1168, __FUNCTION__, (FUNCTION_DECL)))->decl_non_common.result )), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-tailcall.cc" , 1168, __FUNCTION__))->typed.type); |
| 1169 | if (POINTER_TYPE_P (ret_type)(((enum tree_code) (ret_type)->base.code) == POINTER_TYPE || ((enum tree_code) (ret_type)->base.code) == REFERENCE_TYPE )) |
| 1170 | ret_type = sizetypesizetype_tab[(int) stk_sizetype]; |
| 1171 | |
| 1172 | if (act->add && !a_acc) |
| 1173 | a_acc = create_tailcall_accumulator ("add_acc", first, |
| 1174 | build_zero_cst (ret_type)); |
| 1175 | |
| 1176 | if (act->mult && !m_acc) |
| 1177 | m_acc = create_tailcall_accumulator ("mult_acc", first, |
| 1178 | build_one_cst (ret_type)); |
| 1179 | } |
| 1180 | |
| 1181 | if (a_acc || m_acc) |
| 1182 | { |
| 1183 | /* When the tail call elimination using accumulators is performed, |
| 1184 | statements adding the accumulated value are inserted at all exits. |
| 1185 | This turns all other tail calls to non-tail ones. */ |
| 1186 | opt_tailcalls = false; |
| 1187 | } |
| 1188 | |
| 1189 | class loop *new_loop = NULLnullptr; |
| 1190 | for (; tailcalls; tailcalls = next) |
| 1191 | { |
| 1192 | next = tailcalls->next; |
| 1193 | changed |= optimize_tail_call (tailcalls, opt_tailcalls, new_loop); |
| 1194 | free (tailcalls); |
| 1195 | } |
| 1196 | if (new_loop) |
| 1197 | add_loop (new_loop, loops_for_fn (cfun(cfun + 0))->tree_root); |
| 1198 | |
| 1199 | if (a_acc || m_acc) |
| 1200 | { |
| 1201 | /* Modify the remaining return statements. */ |
| 1202 | FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)for ((ei) = ei_start_1 (&(((((cfun + 0))->cfg->x_exit_block_ptr )->preds))); ei_cond ((ei), &(e)); ei_next (&(ei)) ) |
| 1203 | { |
| 1204 | stmt = last_stmt (e->src); |
| 1205 | |
| 1206 | if (stmt |
| 1207 | && gimple_code (stmt) == GIMPLE_RETURN) |
| 1208 | adjust_return_value (e->src, m_acc, a_acc); |
| 1209 | } |
| 1210 | } |
| 1211 | |
| 1212 | if (changed) |
| 1213 | free_dominance_info (CDI_DOMINATORS); |
| 1214 | |
| 1215 | /* Add phi nodes for the virtual operands defined in the function to the |
| 1216 | header of the loop created by tail recursion elimination. Do so |
| 1217 | by triggering the SSA renamer. */ |
| 1218 | if (phis_constructed) |
| 1219 | mark_virtual_operands_for_renaming (cfun(cfun + 0)); |
| 1220 | |
| 1221 | if (tailr_arg_needs_copy) |
| 1222 | BITMAP_FREE (tailr_arg_needs_copy)((void) (bitmap_obstack_free ((bitmap) tailr_arg_needs_copy), (tailr_arg_needs_copy) = (bitmap) nullptr)); |
| 1223 | |
| 1224 | if (changed) |
| 1225 | return TODO_cleanup_cfg(1 << 5) | TODO_update_ssa_only_virtuals(1 << 14); |
| 1226 | return 0; |
| 1227 | } |
| 1228 | |
| 1229 | static bool |
| 1230 | gate_tail_calls (void) |
| 1231 | { |
| 1232 | return flag_optimize_sibling_callsglobal_options.x_flag_optimize_sibling_calls != 0 && dbg_cnt (tail_call); |
| 1233 | } |
| 1234 | |
| 1235 | static unsigned int |
| 1236 | execute_tail_calls (void) |
| 1237 | { |
| 1238 | return tree_optimize_tail_calls_1 (true); |
| 1239 | } |
| 1240 | |
| 1241 | namespace { |
| 1242 | |
| 1243 | const pass_data pass_data_tail_recursion = |
| 1244 | { |
| 1245 | GIMPLE_PASS, /* type */ |
| 1246 | "tailr", /* name */ |
| 1247 | OPTGROUP_NONE, /* optinfo_flags */ |
| 1248 | TV_NONE, /* tv_id */ |
| 1249 | ( PROP_cfg(1 << 3) | PROP_ssa(1 << 5) ), /* properties_required */ |
| 1250 | 0, /* properties_provided */ |
| 1251 | 0, /* properties_destroyed */ |
| 1252 | 0, /* todo_flags_start */ |
| 1253 | 0, /* todo_flags_finish */ |
| 1254 | }; |
| 1255 | |
| 1256 | class pass_tail_recursion : public gimple_opt_pass |
| 1257 | { |
| 1258 | public: |
| 1259 | pass_tail_recursion (gcc::context *ctxt) |
| 1260 | : gimple_opt_pass (pass_data_tail_recursion, ctxt) |
| 1261 | {} |
| 1262 | |
| 1263 | /* opt_pass methods: */ |
| 1264 | opt_pass * clone () final override |
| 1265 | { |
| 1266 | return new pass_tail_recursion (m_ctxt); |
| 1267 | } |
| 1268 | bool gate (function *) final override { return gate_tail_calls (); } |
| 1269 | unsigned int execute (function *) final override |
| 1270 | { |
| 1271 | return tree_optimize_tail_calls_1 (false); |
| 1272 | } |
| 1273 | |
| 1274 | }; // class pass_tail_recursion |
| 1275 | |
| 1276 | } // anon namespace |
| 1277 | |
| 1278 | gimple_opt_pass * |
| 1279 | make_pass_tail_recursion (gcc::context *ctxt) |
| 1280 | { |
| 1281 | return new pass_tail_recursion (ctxt); |
| 1282 | } |
| 1283 | |
| 1284 | namespace { |
| 1285 | |
| 1286 | const pass_data pass_data_tail_calls = |
| 1287 | { |
| 1288 | GIMPLE_PASS, /* type */ |
| 1289 | "tailc", /* name */ |
| 1290 | OPTGROUP_NONE, /* optinfo_flags */ |
| 1291 | TV_NONE, /* tv_id */ |
| 1292 | ( PROP_cfg(1 << 3) | PROP_ssa(1 << 5) ), /* properties_required */ |
| 1293 | 0, /* properties_provided */ |
| 1294 | 0, /* properties_destroyed */ |
| 1295 | 0, /* todo_flags_start */ |
| 1296 | 0, /* todo_flags_finish */ |
| 1297 | }; |
| 1298 | |
| 1299 | class pass_tail_calls : public gimple_opt_pass |
| 1300 | { |
| 1301 | public: |
| 1302 | pass_tail_calls (gcc::context *ctxt) |
| 1303 | : gimple_opt_pass (pass_data_tail_calls, ctxt) |
| 1304 | {} |
| 1305 | |
| 1306 | /* opt_pass methods: */ |
| 1307 | bool gate (function *) final override { return gate_tail_calls (); } |
| 1308 | unsigned int execute (function *) final override |
| 1309 | { |
| 1310 | return execute_tail_calls (); |
| 1311 | } |
| 1312 | |
| 1313 | }; // class pass_tail_calls |
| 1314 | |
| 1315 | } // anon namespace |
| 1316 | |
| 1317 | gimple_opt_pass * |
| 1318 | make_pass_tail_calls (gcc::context *ctxt) |
| 1319 | { |
| 1320 | return new pass_tail_calls (ctxt); |
| 1321 | } |