1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526
|
/* Lower vector operations to scalar operations.
Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.
GCC is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "tm.h"
#include "rtl.h"
#include "expr.h"
#include "insn-codes.h"
#include "diagnostic.h"
#include "optabs.h"
#include "machmode.h"
#include "langhooks.h"
#include "tree-flow.h"
#include "tree-gimple.h"
#include "tree-iterator.h"
#include "tree-pass.h"
#include "flags.h"
#include "ggc.h"
/* Build a constant of type TYPE, made of VALUE's bits replicated
every TYPE_SIZE (INNER_TYPE) bits to fit TYPE's precision. */
static tree
build_replicated_const (tree type, tree inner_type, HOST_WIDE_INT value)
{
int width = tree_low_cst (TYPE_SIZE (inner_type), 1);
int n = HOST_BITS_PER_WIDE_INT / width;
unsigned HOST_WIDE_INT low, high, mask;
tree ret;
gcc_assert (n);
if (width == HOST_BITS_PER_WIDE_INT)
low = value;
else
{
mask = ((HOST_WIDE_INT)1 << width) - 1;
low = (unsigned HOST_WIDE_INT) ~0 / mask * (value & mask);
}
if (TYPE_PRECISION (type) < HOST_BITS_PER_WIDE_INT)
low &= ((HOST_WIDE_INT)1 << TYPE_PRECISION (type)) - 1, high = 0;
else if (TYPE_PRECISION (type) == HOST_BITS_PER_WIDE_INT)
high = 0;
else if (TYPE_PRECISION (type) == 2 * HOST_BITS_PER_WIDE_INT)
high = low;
else
gcc_unreachable ();
ret = build_int_cst_wide (type, low, high);
return ret;
}
static GTY(()) tree vector_inner_type;
static GTY(()) tree vector_last_type;
static GTY(()) int vector_last_nunits;
/* Return a suitable vector types made of SUBPARTS units each of mode
"word_mode" (the global variable). */
static tree
build_word_mode_vector_type (int nunits)
{
if (!vector_inner_type)
vector_inner_type = lang_hooks.types.type_for_mode (word_mode, 1);
else if (vector_last_nunits == nunits)
{
gcc_assert (TREE_CODE (vector_last_type) == VECTOR_TYPE);
return vector_last_type;
}
/* We build a new type, but we canonicalize it nevertheless,
because it still saves some memory. */
vector_last_nunits = nunits;
vector_last_type = type_hash_canon (nunits,
build_vector_type (vector_inner_type,
nunits));
return vector_last_type;
}
typedef tree (*elem_op_func) (block_stmt_iterator *,
tree, tree, tree, tree, tree, enum tree_code);
static inline tree
tree_vec_extract (block_stmt_iterator *bsi, tree type,
tree t, tree bitsize, tree bitpos)
{
if (bitpos)
return gimplify_build3 (bsi, BIT_FIELD_REF, type, t, bitsize, bitpos);
else
return gimplify_build1 (bsi, VIEW_CONVERT_EXPR, type, t);
}
static tree
do_unop (block_stmt_iterator *bsi, tree inner_type, tree a,
tree b ATTRIBUTE_UNUSED, tree bitpos, tree bitsize,
enum tree_code code)
{
a = tree_vec_extract (bsi, inner_type, a, bitsize, bitpos);
return gimplify_build1 (bsi, code, inner_type, a);
}
static tree
do_binop (block_stmt_iterator *bsi, tree inner_type, tree a, tree b,
tree bitpos, tree bitsize, enum tree_code code)
{
a = tree_vec_extract (bsi, inner_type, a, bitsize, bitpos);
b = tree_vec_extract (bsi, inner_type, b, bitsize, bitpos);
return gimplify_build2 (bsi, code, inner_type, a, b);
}
/* Expand vector addition to scalars. This does bit twiddling
in order to increase parallelism:
a + b = (((int) a & 0x7f7f7f7f) + ((int) b & 0x7f7f7f7f)) ^
(a ^ b) & 0x80808080
a - b = (((int) a | 0x80808080) - ((int) b & 0x7f7f7f7f)) ^
(a ^ ~b) & 0x80808080
-b = (0x80808080 - ((int) b & 0x7f7f7f7f)) ^ (~b & 0x80808080)
This optimization should be done only if 4 vector items or more
fit into a word. */
static tree
do_plus_minus (block_stmt_iterator *bsi, tree word_type, tree a, tree b,
tree bitpos ATTRIBUTE_UNUSED, tree bitsize ATTRIBUTE_UNUSED,
enum tree_code code)
{
tree inner_type = TREE_TYPE (TREE_TYPE (a));
unsigned HOST_WIDE_INT max;
tree low_bits, high_bits, a_low, b_low, result_low, signs;
max = GET_MODE_MASK (TYPE_MODE (inner_type));
low_bits = build_replicated_const (word_type, inner_type, max >> 1);
high_bits = build_replicated_const (word_type, inner_type, max & ~(max >> 1));
a = tree_vec_extract (bsi, word_type, a, bitsize, bitpos);
b = tree_vec_extract (bsi, word_type, b, bitsize, bitpos);
signs = gimplify_build2 (bsi, BIT_XOR_EXPR, word_type, a, b);
b_low = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, b, low_bits);
if (code == PLUS_EXPR)
a_low = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, a, low_bits);
else
{
a_low = gimplify_build2 (bsi, BIT_IOR_EXPR, word_type, a, high_bits);
signs = gimplify_build1 (bsi, BIT_NOT_EXPR, word_type, signs);
}
signs = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, signs, high_bits);
result_low = gimplify_build2 (bsi, code, word_type, a_low, b_low);
return gimplify_build2 (bsi, BIT_XOR_EXPR, word_type, result_low, signs);
}
static tree
do_negate (block_stmt_iterator *bsi, tree word_type, tree b,
tree unused ATTRIBUTE_UNUSED, tree bitpos ATTRIBUTE_UNUSED,
tree bitsize ATTRIBUTE_UNUSED,
enum tree_code code ATTRIBUTE_UNUSED)
{
tree inner_type = TREE_TYPE (TREE_TYPE (b));
HOST_WIDE_INT max;
tree low_bits, high_bits, b_low, result_low, signs;
max = GET_MODE_MASK (TYPE_MODE (inner_type));
low_bits = build_replicated_const (word_type, inner_type, max >> 1);
high_bits = build_replicated_const (word_type, inner_type, max & ~(max >> 1));
b = tree_vec_extract (bsi, word_type, b, bitsize, bitpos);
b_low = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, b, low_bits);
signs = gimplify_build1 (bsi, BIT_NOT_EXPR, word_type, b);
signs = gimplify_build2 (bsi, BIT_AND_EXPR, word_type, signs, high_bits);
result_low = gimplify_build2 (bsi, MINUS_EXPR, word_type, high_bits, b_low);
return gimplify_build2 (bsi, BIT_XOR_EXPR, word_type, result_low, signs);
}
/* Expand a vector operation to scalars, by using many operations
whose type is the vector type's inner type. */
static tree
expand_vector_piecewise (block_stmt_iterator *bsi, elem_op_func f,
tree type, tree inner_type,
tree a, tree b, enum tree_code code)
{
VEC(constructor_elt,gc) *v;
tree part_width = TYPE_SIZE (inner_type);
tree index = bitsize_int (0);
int nunits = TYPE_VECTOR_SUBPARTS (type);
int delta = tree_low_cst (part_width, 1)
/ tree_low_cst (TYPE_SIZE (TREE_TYPE (type)), 1);
int i;
v = VEC_alloc(constructor_elt, gc, (nunits + delta - 1) / delta);
for (i = 0; i < nunits;
i += delta, index = int_const_binop (PLUS_EXPR, index, part_width, 0))
{
tree result = f (bsi, inner_type, a, b, index, part_width, code);
constructor_elt *ce = VEC_quick_push (constructor_elt, v, NULL);
ce->index = NULL_TREE;
ce->value = result;
}
return build_constructor (type, v);
}
/* Expand a vector operation to scalars with the freedom to use
a scalar integer type, or to use a different size for the items
in the vector type. */
static tree
expand_vector_parallel (block_stmt_iterator *bsi, elem_op_func f, tree type,
tree a, tree b,
enum tree_code code)
{
tree result, compute_type;
enum machine_mode mode;
int n_words = tree_low_cst (TYPE_SIZE_UNIT (type), 1) / UNITS_PER_WORD;
/* We have three strategies. If the type is already correct, just do
the operation an element at a time. Else, if the vector is wider than
one word, do it a word at a time; finally, if the vector is smaller
than one word, do it as a scalar. */
if (TYPE_MODE (TREE_TYPE (type)) == word_mode)
return expand_vector_piecewise (bsi, f,
type, TREE_TYPE (type),
a, b, code);
else if (n_words > 1)
{
tree word_type = build_word_mode_vector_type (n_words);
result = expand_vector_piecewise (bsi, f,
word_type, TREE_TYPE (word_type),
a, b, code);
result = gimplify_val (bsi, word_type, result);
}
else
{
/* Use a single scalar operation with a mode no wider than word_mode. */
mode = mode_for_size (tree_low_cst (TYPE_SIZE (type), 1), MODE_INT, 0);
compute_type = lang_hooks.types.type_for_mode (mode, 1);
result = f (bsi, compute_type, a, b, NULL_TREE, NULL_TREE, code);
}
return result;
}
/* Expand a vector operation to scalars; for integer types we can use
special bit twiddling tricks to do the sums a word at a time, using
function F_PARALLEL instead of F. These tricks are done only if
they can process at least four items, that is, only if the vector
holds at least four items and if a word can hold four items. */
static tree
expand_vector_addition (block_stmt_iterator *bsi,
elem_op_func f, elem_op_func f_parallel,
tree type, tree a, tree b, enum tree_code code)
{
int parts_per_word = UNITS_PER_WORD
/ tree_low_cst (TYPE_SIZE_UNIT (TREE_TYPE (type)), 1);
if (INTEGRAL_TYPE_P (TREE_TYPE (type))
&& parts_per_word >= 4
&& TYPE_VECTOR_SUBPARTS (type) >= 4)
return expand_vector_parallel (bsi, f_parallel,
type, a, b, code);
else
return expand_vector_piecewise (bsi, f,
type, TREE_TYPE (type),
a, b, code);
}
static tree
expand_vector_operation (block_stmt_iterator *bsi, tree type, tree compute_type,
tree rhs, enum tree_code code)
{
enum machine_mode compute_mode = TYPE_MODE (compute_type);
/* If the compute mode is not a vector mode (hence we are not decomposing
a BLKmode vector to smaller, hardware-supported vectors), we may want
to expand the operations in parallel. */
if (GET_MODE_CLASS (compute_mode) != MODE_VECTOR_INT
&& GET_MODE_CLASS (compute_mode) != MODE_VECTOR_FLOAT)
switch (code)
{
case PLUS_EXPR:
case MINUS_EXPR:
if (!TYPE_OVERFLOW_TRAPS (type))
return expand_vector_addition (bsi, do_binop, do_plus_minus, type,
TREE_OPERAND (rhs, 0),
TREE_OPERAND (rhs, 1), code);
break;
case NEGATE_EXPR:
if (!TYPE_OVERFLOW_TRAPS (type))
return expand_vector_addition (bsi, do_unop, do_negate, type,
TREE_OPERAND (rhs, 0),
NULL_TREE, code);
break;
case BIT_AND_EXPR:
case BIT_IOR_EXPR:
case BIT_XOR_EXPR:
return expand_vector_parallel (bsi, do_binop, type,
TREE_OPERAND (rhs, 0),
TREE_OPERAND (rhs, 1), code);
case BIT_NOT_EXPR:
return expand_vector_parallel (bsi, do_unop, type,
TREE_OPERAND (rhs, 0),
NULL_TREE, code);
default:
break;
}
if (TREE_CODE_CLASS (code) == tcc_unary)
return expand_vector_piecewise (bsi, do_unop, type, compute_type,
TREE_OPERAND (rhs, 0),
NULL_TREE, code);
else
return expand_vector_piecewise (bsi, do_binop, type, compute_type,
TREE_OPERAND (rhs, 0),
TREE_OPERAND (rhs, 1), code);
}
/* Return a type for the widest vector mode whose components are of mode
INNER_MODE, or NULL_TREE if none is found. */
static tree
type_for_widest_vector_mode (enum machine_mode inner_mode, optab op)
{
enum machine_mode best_mode = VOIDmode, mode;
int best_nunits = 0;
if (SCALAR_FLOAT_MODE_P (inner_mode))
mode = MIN_MODE_VECTOR_FLOAT;
else
mode = MIN_MODE_VECTOR_INT;
for (; mode != VOIDmode; mode = GET_MODE_WIDER_MODE (mode))
if (GET_MODE_INNER (mode) == inner_mode
&& GET_MODE_NUNITS (mode) > best_nunits
&& op->handlers[mode].insn_code != CODE_FOR_nothing)
best_mode = mode, best_nunits = GET_MODE_NUNITS (mode);
if (best_mode == VOIDmode)
return NULL_TREE;
else
return lang_hooks.types.type_for_mode (best_mode, 1);
}
/* Process one statement. If we identify a vector operation, expand it. */
static void
expand_vector_operations_1 (block_stmt_iterator *bsi)
{
tree stmt = bsi_stmt (*bsi);
tree *p_lhs, *p_rhs, lhs, rhs, type, compute_type;
enum tree_code code;
enum machine_mode compute_mode;
optab op;
switch (TREE_CODE (stmt))
{
case RETURN_EXPR:
stmt = TREE_OPERAND (stmt, 0);
if (!stmt || TREE_CODE (stmt) != MODIFY_EXPR)
return;
/* FALLTHRU */
case MODIFY_EXPR:
p_lhs = &TREE_OPERAND (stmt, 0);
p_rhs = &TREE_OPERAND (stmt, 1);
lhs = *p_lhs;
rhs = *p_rhs;
break;
default:
return;
}
type = TREE_TYPE (rhs);
if (TREE_CODE (type) != VECTOR_TYPE)
return;
code = TREE_CODE (rhs);
if (TREE_CODE_CLASS (code) != tcc_unary
&& TREE_CODE_CLASS (code) != tcc_binary)
return;
if (code == NOP_EXPR || code == VIEW_CONVERT_EXPR)
return;
gcc_assert (code != CONVERT_EXPR);
op = optab_for_tree_code (code, type);
/* For widening vector operations, the relevant type is of the arguments,
not the widened result. */
if (code == WIDEN_SUM_EXPR)
type = TREE_TYPE (TREE_OPERAND (rhs, 0));
/* Optabs will try converting a negation into a subtraction, so
look for it as well. TODO: negation of floating-point vectors
might be turned into an exclusive OR toggling the sign bit. */
if (op == NULL
&& code == NEGATE_EXPR
&& INTEGRAL_TYPE_P (TREE_TYPE (type)))
op = optab_for_tree_code (MINUS_EXPR, type);
/* For very wide vectors, try using a smaller vector mode. */
compute_type = type;
if (TYPE_MODE (type) == BLKmode && op)
{
tree vector_compute_type
= type_for_widest_vector_mode (TYPE_MODE (TREE_TYPE (type)), op);
if (vector_compute_type != NULL_TREE)
compute_type = vector_compute_type;
}
/* If we are breaking a BLKmode vector into smaller pieces,
type_for_widest_vector_mode has already looked into the optab,
so skip these checks. */
if (compute_type == type)
{
compute_mode = TYPE_MODE (compute_type);
if ((GET_MODE_CLASS (compute_mode) == MODE_VECTOR_INT
|| GET_MODE_CLASS (compute_mode) == MODE_VECTOR_FLOAT)
&& op != NULL
&& op->handlers[compute_mode].insn_code != CODE_FOR_nothing)
return;
else
/* There is no operation in hardware, so fall back to scalars. */
compute_type = TREE_TYPE (type);
}
gcc_assert (code != VEC_LSHIFT_EXPR && code != VEC_RSHIFT_EXPR);
rhs = expand_vector_operation (bsi, type, compute_type, rhs, code);
if (lang_hooks.types_compatible_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
*p_rhs = rhs;
else
*p_rhs = gimplify_build1 (bsi, VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs);
mark_stmt_modified (bsi_stmt (*bsi));
}
/* Use this to lower vector operations introduced by the vectorizer,
if it may need the bit-twiddling tricks implemented in this file. */
static bool
gate_expand_vector_operations (void)
{
return flag_tree_vectorize != 0;
}
static unsigned int
expand_vector_operations (void)
{
block_stmt_iterator bsi;
basic_block bb;
FOR_EACH_BB (bb)
{
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
{
expand_vector_operations_1 (&bsi);
update_stmt_if_modified (bsi_stmt (bsi));
}
}
return 0;
}
struct tree_opt_pass pass_lower_vector =
{
"veclower", /* name */
0, /* gate */
expand_vector_operations, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
0, /* tv_id */
PROP_cfg, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func | TODO_ggc_collect
| TODO_verify_stmts, /* todo_flags_finish */
0 /* letter */
};
struct tree_opt_pass pass_lower_vector_ssa =
{
"veclower2", /* name */
gate_expand_vector_operations, /* gate */
expand_vector_operations, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
0, /* tv_id */
PROP_cfg, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func | TODO_update_ssa /* todo_flags_finish */
| TODO_verify_ssa
| TODO_verify_stmts | TODO_verify_flow,
0 /* letter */
};
#include "gt-tree-vect-generic.h"
|