1// Copyright 2014 the V8 project authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#include "src/compiler/machine-operator-reducer.h" 6 7#include "src/base/bits.h" 8#include "src/compiler/generic-node-inl.h" 9#include "src/compiler/graph.h" 10#include "src/compiler/js-graph.h" 11#include "src/compiler/node-matchers.h" 12 13namespace v8 { 14namespace internal { 15namespace compiler { 16 17MachineOperatorReducer::MachineOperatorReducer(JSGraph* jsgraph) 18 : jsgraph_(jsgraph) {} 19 20 21MachineOperatorReducer::~MachineOperatorReducer() {} 22 23 24Node* MachineOperatorReducer::Float32Constant(volatile float value) { 25 return graph()->NewNode(common()->Float32Constant(value)); 26} 27 28 29Node* MachineOperatorReducer::Float64Constant(volatile double value) { 30 return jsgraph()->Float64Constant(value); 31} 32 33 34Node* MachineOperatorReducer::Int32Constant(int32_t value) { 35 return jsgraph()->Int32Constant(value); 36} 37 38 39Node* MachineOperatorReducer::Int64Constant(int64_t value) { 40 return graph()->NewNode(common()->Int64Constant(value)); 41} 42 43 44// Perform constant folding and strength reduction on machine operators. 45Reduction MachineOperatorReducer::Reduce(Node* node) { 46 switch (node->opcode()) { 47 case IrOpcode::kProjection: 48 return ReduceProjection(OpParameter<size_t>(node), node->InputAt(0)); 49 case IrOpcode::kWord32And: { 50 Int32BinopMatcher m(node); 51 if (m.right().Is(0)) return Replace(m.right().node()); // x & 0 => 0 52 if (m.right().Is(-1)) return Replace(m.left().node()); // x & -1 => x 53 if (m.IsFoldable()) { // K & K => K 54 return ReplaceInt32(m.left().Value() & m.right().Value()); 55 } 56 if (m.LeftEqualsRight()) return Replace(m.left().node()); // x & x => x 57 break; 58 } 59 case IrOpcode::kWord32Or: { 60 Int32BinopMatcher m(node); 61 if (m.right().Is(0)) return Replace(m.left().node()); // x | 0 => x 62 if (m.right().Is(-1)) return Replace(m.right().node()); // x | -1 => -1 63 if (m.IsFoldable()) { // K | K => K 64 return ReplaceInt32(m.left().Value() | m.right().Value()); 65 } 66 if (m.LeftEqualsRight()) return Replace(m.left().node()); // x | x => x 67 if (m.left().IsWord32Shl() && m.right().IsWord32Shr()) { 68 Int32BinopMatcher mleft(m.left().node()); 69 Int32BinopMatcher mright(m.right().node()); 70 if (mleft.left().node() == mright.left().node()) { 71 // (x << y) | (x >> (32 - y)) => x ror y 72 if (mright.right().IsInt32Sub()) { 73 Int32BinopMatcher mrightright(mright.right().node()); 74 if (mrightright.left().Is(32) && 75 mrightright.right().node() == mleft.right().node()) { 76 node->set_op(machine()->Word32Ror()); 77 node->ReplaceInput(0, mleft.left().node()); 78 node->ReplaceInput(1, mleft.right().node()); 79 return Changed(node); 80 } 81 } 82 // (x << K) | (x >> (32 - K)) => x ror K 83 if (mleft.right().IsInRange(0, 31) && 84 mright.right().Is(32 - mleft.right().Value())) { 85 node->set_op(machine()->Word32Ror()); 86 node->ReplaceInput(0, mleft.left().node()); 87 node->ReplaceInput(1, mleft.right().node()); 88 return Changed(node); 89 } 90 } 91 } 92 if (m.left().IsWord32Shr() && m.right().IsWord32Shl()) { 93 // (x >> (32 - y)) | (x << y) => x ror y 94 Int32BinopMatcher mleft(m.left().node()); 95 Int32BinopMatcher mright(m.right().node()); 96 if (mleft.left().node() == mright.left().node()) { 97 if (mleft.right().IsInt32Sub()) { 98 Int32BinopMatcher mleftright(mleft.right().node()); 99 if (mleftright.left().Is(32) && 100 mleftright.right().node() == mright.right().node()) { 101 node->set_op(machine()->Word32Ror()); 102 node->ReplaceInput(0, mright.left().node()); 103 node->ReplaceInput(1, mright.right().node()); 104 return Changed(node); 105 } 106 } 107 // (x >> (32 - K)) | (x << K) => x ror K 108 if (mright.right().IsInRange(0, 31) && 109 mleft.right().Is(32 - mright.right().Value())) { 110 node->set_op(machine()->Word32Ror()); 111 node->ReplaceInput(0, mright.left().node()); 112 node->ReplaceInput(1, mright.right().node()); 113 return Changed(node); 114 } 115 } 116 } 117 break; 118 } 119 case IrOpcode::kWord32Xor: { 120 Int32BinopMatcher m(node); 121 if (m.right().Is(0)) return Replace(m.left().node()); // x ^ 0 => x 122 if (m.IsFoldable()) { // K ^ K => K 123 return ReplaceInt32(m.left().Value() ^ m.right().Value()); 124 } 125 if (m.LeftEqualsRight()) return ReplaceInt32(0); // x ^ x => 0 126 break; 127 } 128 case IrOpcode::kWord32Shl: { 129 Int32BinopMatcher m(node); 130 if (m.right().Is(0)) return Replace(m.left().node()); // x << 0 => x 131 if (m.IsFoldable()) { // K << K => K 132 return ReplaceInt32(m.left().Value() << m.right().Value()); 133 } 134 break; 135 } 136 case IrOpcode::kWord32Shr: { 137 Uint32BinopMatcher m(node); 138 if (m.right().Is(0)) return Replace(m.left().node()); // x >>> 0 => x 139 if (m.IsFoldable()) { // K >>> K => K 140 return ReplaceInt32(m.left().Value() >> m.right().Value()); 141 } 142 break; 143 } 144 case IrOpcode::kWord32Sar: { 145 Int32BinopMatcher m(node); 146 if (m.right().Is(0)) return Replace(m.left().node()); // x >> 0 => x 147 if (m.IsFoldable()) { // K >> K => K 148 return ReplaceInt32(m.left().Value() >> m.right().Value()); 149 } 150 break; 151 } 152 case IrOpcode::kWord32Ror: { 153 Int32BinopMatcher m(node); 154 if (m.right().Is(0)) return Replace(m.left().node()); // x ror 0 => x 155 if (m.IsFoldable()) { // K ror K => K 156 return ReplaceInt32( 157 base::bits::RotateRight32(m.left().Value(), m.right().Value())); 158 } 159 break; 160 } 161 case IrOpcode::kWord32Equal: { 162 Int32BinopMatcher m(node); 163 if (m.IsFoldable()) { // K == K => K 164 return ReplaceBool(m.left().Value() == m.right().Value()); 165 } 166 if (m.left().IsInt32Sub() && m.right().Is(0)) { // x - y == 0 => x == y 167 Int32BinopMatcher msub(m.left().node()); 168 node->ReplaceInput(0, msub.left().node()); 169 node->ReplaceInput(1, msub.right().node()); 170 return Changed(node); 171 } 172 // TODO(turbofan): fold HeapConstant, ExternalReference, pointer compares 173 if (m.LeftEqualsRight()) return ReplaceBool(true); // x == x => true 174 break; 175 } 176 case IrOpcode::kInt32Add: { 177 Int32BinopMatcher m(node); 178 if (m.right().Is(0)) return Replace(m.left().node()); // x + 0 => x 179 if (m.IsFoldable()) { // K + K => K 180 return ReplaceInt32(static_cast<uint32_t>(m.left().Value()) + 181 static_cast<uint32_t>(m.right().Value())); 182 } 183 break; 184 } 185 case IrOpcode::kInt32Sub: { 186 Int32BinopMatcher m(node); 187 if (m.right().Is(0)) return Replace(m.left().node()); // x - 0 => x 188 if (m.IsFoldable()) { // K - K => K 189 return ReplaceInt32(static_cast<uint32_t>(m.left().Value()) - 190 static_cast<uint32_t>(m.right().Value())); 191 } 192 if (m.LeftEqualsRight()) return ReplaceInt32(0); // x - x => 0 193 break; 194 } 195 case IrOpcode::kInt32Mul: { 196 Int32BinopMatcher m(node); 197 if (m.right().Is(0)) return Replace(m.right().node()); // x * 0 => 0 198 if (m.right().Is(1)) return Replace(m.left().node()); // x * 1 => x 199 if (m.IsFoldable()) { // K * K => K 200 return ReplaceInt32(m.left().Value() * m.right().Value()); 201 } 202 if (m.right().Is(-1)) { // x * -1 => 0 - x 203 node->set_op(machine()->Int32Sub()); 204 node->ReplaceInput(0, Int32Constant(0)); 205 node->ReplaceInput(1, m.left().node()); 206 return Changed(node); 207 } 208 if (m.right().IsPowerOf2()) { // x * 2^n => x << n 209 node->set_op(machine()->Word32Shl()); 210 node->ReplaceInput(1, Int32Constant(WhichPowerOf2(m.right().Value()))); 211 return Changed(node); 212 } 213 break; 214 } 215 case IrOpcode::kInt32Div: { 216 Int32BinopMatcher m(node); 217 if (m.right().Is(1)) return Replace(m.left().node()); // x / 1 => x 218 // TODO(turbofan): if (m.left().Is(0)) 219 // TODO(turbofan): if (m.right().IsPowerOf2()) 220 // TODO(turbofan): if (m.right().Is(0)) 221 // TODO(turbofan): if (m.LeftEqualsRight()) 222 if (m.IsFoldable() && !m.right().Is(0)) { // K / K => K 223 if (m.right().Is(-1)) return ReplaceInt32(-m.left().Value()); 224 return ReplaceInt32(m.left().Value() / m.right().Value()); 225 } 226 if (m.right().Is(-1)) { // x / -1 => 0 - x 227 node->set_op(machine()->Int32Sub()); 228 node->ReplaceInput(0, Int32Constant(0)); 229 node->ReplaceInput(1, m.left().node()); 230 return Changed(node); 231 } 232 break; 233 } 234 case IrOpcode::kInt32UDiv: { 235 Uint32BinopMatcher m(node); 236 if (m.right().Is(1)) return Replace(m.left().node()); // x / 1 => x 237 // TODO(turbofan): if (m.left().Is(0)) 238 // TODO(turbofan): if (m.right().Is(0)) 239 // TODO(turbofan): if (m.LeftEqualsRight()) 240 if (m.IsFoldable() && !m.right().Is(0)) { // K / K => K 241 return ReplaceInt32(m.left().Value() / m.right().Value()); 242 } 243 if (m.right().IsPowerOf2()) { // x / 2^n => x >> n 244 node->set_op(machine()->Word32Shr()); 245 node->ReplaceInput(1, Int32Constant(WhichPowerOf2(m.right().Value()))); 246 return Changed(node); 247 } 248 break; 249 } 250 case IrOpcode::kInt32Mod: { 251 Int32BinopMatcher m(node); 252 if (m.right().Is(1)) return ReplaceInt32(0); // x % 1 => 0 253 if (m.right().Is(-1)) return ReplaceInt32(0); // x % -1 => 0 254 // TODO(turbofan): if (m.left().Is(0)) 255 // TODO(turbofan): if (m.right().IsPowerOf2()) 256 // TODO(turbofan): if (m.right().Is(0)) 257 // TODO(turbofan): if (m.LeftEqualsRight()) 258 if (m.IsFoldable() && !m.right().Is(0)) { // K % K => K 259 return ReplaceInt32(m.left().Value() % m.right().Value()); 260 } 261 break; 262 } 263 case IrOpcode::kInt32UMod: { 264 Uint32BinopMatcher m(node); 265 if (m.right().Is(1)) return ReplaceInt32(0); // x % 1 => 0 266 // TODO(turbofan): if (m.left().Is(0)) 267 // TODO(turbofan): if (m.right().Is(0)) 268 // TODO(turbofan): if (m.LeftEqualsRight()) 269 if (m.IsFoldable() && !m.right().Is(0)) { // K % K => K 270 return ReplaceInt32(m.left().Value() % m.right().Value()); 271 } 272 if (m.right().IsPowerOf2()) { // x % 2^n => x & 2^n-1 273 node->set_op(machine()->Word32And()); 274 node->ReplaceInput(1, Int32Constant(m.right().Value() - 1)); 275 return Changed(node); 276 } 277 break; 278 } 279 case IrOpcode::kInt32LessThan: { 280 Int32BinopMatcher m(node); 281 if (m.IsFoldable()) { // K < K => K 282 return ReplaceBool(m.left().Value() < m.right().Value()); 283 } 284 if (m.left().IsInt32Sub() && m.right().Is(0)) { // x - y < 0 => x < y 285 Int32BinopMatcher msub(m.left().node()); 286 node->ReplaceInput(0, msub.left().node()); 287 node->ReplaceInput(1, msub.right().node()); 288 return Changed(node); 289 } 290 if (m.left().Is(0) && m.right().IsInt32Sub()) { // 0 < x - y => y < x 291 Int32BinopMatcher msub(m.right().node()); 292 node->ReplaceInput(0, msub.right().node()); 293 node->ReplaceInput(1, msub.left().node()); 294 return Changed(node); 295 } 296 if (m.LeftEqualsRight()) return ReplaceBool(false); // x < x => false 297 break; 298 } 299 case IrOpcode::kInt32LessThanOrEqual: { 300 Int32BinopMatcher m(node); 301 if (m.IsFoldable()) { // K <= K => K 302 return ReplaceBool(m.left().Value() <= m.right().Value()); 303 } 304 if (m.left().IsInt32Sub() && m.right().Is(0)) { // x - y <= 0 => x <= y 305 Int32BinopMatcher msub(m.left().node()); 306 node->ReplaceInput(0, msub.left().node()); 307 node->ReplaceInput(1, msub.right().node()); 308 return Changed(node); 309 } 310 if (m.left().Is(0) && m.right().IsInt32Sub()) { // 0 <= x - y => y <= x 311 Int32BinopMatcher msub(m.right().node()); 312 node->ReplaceInput(0, msub.right().node()); 313 node->ReplaceInput(1, msub.left().node()); 314 return Changed(node); 315 } 316 if (m.LeftEqualsRight()) return ReplaceBool(true); // x <= x => true 317 break; 318 } 319 case IrOpcode::kUint32LessThan: { 320 Uint32BinopMatcher m(node); 321 if (m.left().Is(kMaxUInt32)) return ReplaceBool(false); // M < x => false 322 if (m.right().Is(0)) return ReplaceBool(false); // x < 0 => false 323 if (m.IsFoldable()) { // K < K => K 324 return ReplaceBool(m.left().Value() < m.right().Value()); 325 } 326 if (m.LeftEqualsRight()) return ReplaceBool(false); // x < x => false 327 break; 328 } 329 case IrOpcode::kUint32LessThanOrEqual: { 330 Uint32BinopMatcher m(node); 331 if (m.left().Is(0)) return ReplaceBool(true); // 0 <= x => true 332 if (m.right().Is(kMaxUInt32)) return ReplaceBool(true); // x <= M => true 333 if (m.IsFoldable()) { // K <= K => K 334 return ReplaceBool(m.left().Value() <= m.right().Value()); 335 } 336 if (m.LeftEqualsRight()) return ReplaceBool(true); // x <= x => true 337 break; 338 } 339 case IrOpcode::kFloat64Add: { 340 Float64BinopMatcher m(node); 341 if (m.IsFoldable()) { // K + K => K 342 return ReplaceFloat64(m.left().Value() + m.right().Value()); 343 } 344 break; 345 } 346 case IrOpcode::kFloat64Sub: { 347 Float64BinopMatcher m(node); 348 if (m.IsFoldable()) { // K - K => K 349 return ReplaceFloat64(m.left().Value() - m.right().Value()); 350 } 351 break; 352 } 353 case IrOpcode::kFloat64Mul: { 354 Float64BinopMatcher m(node); 355 if (m.right().Is(1)) return Replace(m.left().node()); // x * 1.0 => x 356 if (m.right().IsNaN()) { // x * NaN => NaN 357 return Replace(m.right().node()); 358 } 359 if (m.IsFoldable()) { // K * K => K 360 return ReplaceFloat64(m.left().Value() * m.right().Value()); 361 } 362 break; 363 } 364 case IrOpcode::kFloat64Div: { 365 Float64BinopMatcher m(node); 366 if (m.right().Is(1)) return Replace(m.left().node()); // x / 1.0 => x 367 if (m.right().IsNaN()) { // x / NaN => NaN 368 return Replace(m.right().node()); 369 } 370 if (m.left().IsNaN()) { // NaN / x => NaN 371 return Replace(m.left().node()); 372 } 373 if (m.IsFoldable()) { // K / K => K 374 return ReplaceFloat64(m.left().Value() / m.right().Value()); 375 } 376 break; 377 } 378 case IrOpcode::kFloat64Mod: { 379 Float64BinopMatcher m(node); 380 if (m.right().IsNaN()) { // x % NaN => NaN 381 return Replace(m.right().node()); 382 } 383 if (m.left().IsNaN()) { // NaN % x => NaN 384 return Replace(m.left().node()); 385 } 386 if (m.IsFoldable()) { // K % K => K 387 return ReplaceFloat64(modulo(m.left().Value(), m.right().Value())); 388 } 389 break; 390 } 391 case IrOpcode::kChangeFloat32ToFloat64: { 392 Float32Matcher m(node->InputAt(0)); 393 if (m.HasValue()) return ReplaceFloat64(m.Value()); 394 break; 395 } 396 case IrOpcode::kChangeFloat64ToInt32: { 397 Float64Matcher m(node->InputAt(0)); 398 if (m.HasValue()) return ReplaceInt32(FastD2I(m.Value())); 399 if (m.IsChangeInt32ToFloat64()) return Replace(m.node()->InputAt(0)); 400 break; 401 } 402 case IrOpcode::kChangeFloat64ToUint32: { 403 Float64Matcher m(node->InputAt(0)); 404 if (m.HasValue()) return ReplaceInt32(FastD2UI(m.Value())); 405 if (m.IsChangeUint32ToFloat64()) return Replace(m.node()->InputAt(0)); 406 break; 407 } 408 case IrOpcode::kChangeInt32ToFloat64: { 409 Int32Matcher m(node->InputAt(0)); 410 if (m.HasValue()) return ReplaceFloat64(FastI2D(m.Value())); 411 break; 412 } 413 case IrOpcode::kChangeInt32ToInt64: { 414 Int32Matcher m(node->InputAt(0)); 415 if (m.HasValue()) return ReplaceInt64(m.Value()); 416 break; 417 } 418 case IrOpcode::kChangeUint32ToFloat64: { 419 Uint32Matcher m(node->InputAt(0)); 420 if (m.HasValue()) return ReplaceFloat64(FastUI2D(m.Value())); 421 break; 422 } 423 case IrOpcode::kChangeUint32ToUint64: { 424 Uint32Matcher m(node->InputAt(0)); 425 if (m.HasValue()) return ReplaceInt64(static_cast<uint64_t>(m.Value())); 426 break; 427 } 428 case IrOpcode::kTruncateFloat64ToInt32: { 429 Float64Matcher m(node->InputAt(0)); 430 if (m.HasValue()) return ReplaceInt32(DoubleToInt32(m.Value())); 431 if (m.IsChangeInt32ToFloat64()) return Replace(m.node()->InputAt(0)); 432 break; 433 } 434 case IrOpcode::kTruncateInt64ToInt32: { 435 Int64Matcher m(node->InputAt(0)); 436 if (m.HasValue()) return ReplaceInt32(static_cast<int32_t>(m.Value())); 437 if (m.IsChangeInt32ToInt64()) return Replace(m.node()->InputAt(0)); 438 break; 439 } 440 case IrOpcode::kTruncateFloat64ToFloat32: { 441 Float64Matcher m(node->InputAt(0)); 442 if (m.HasValue()) return ReplaceFloat32(DoubleToFloat32(m.Value())); 443 if (m.IsChangeFloat32ToFloat64()) return Replace(m.node()->InputAt(0)); 444 break; 445 } 446 default: 447 break; 448 } 449 return NoChange(); 450} 451 452 453Reduction MachineOperatorReducer::ReduceProjection(size_t index, Node* node) { 454 switch (node->opcode()) { 455 case IrOpcode::kInt32AddWithOverflow: { 456 DCHECK(index == 0 || index == 1); 457 Int32BinopMatcher m(node); 458 if (m.IsFoldable()) { 459 int32_t val; 460 bool ovf = base::bits::SignedAddOverflow32(m.left().Value(), 461 m.right().Value(), &val); 462 return ReplaceInt32((index == 0) ? val : ovf); 463 } 464 if (m.right().Is(0)) { 465 return (index == 0) ? Replace(m.left().node()) : ReplaceInt32(0); 466 } 467 break; 468 } 469 case IrOpcode::kInt32SubWithOverflow: { 470 DCHECK(index == 0 || index == 1); 471 Int32BinopMatcher m(node); 472 if (m.IsFoldable()) { 473 int32_t val; 474 bool ovf = base::bits::SignedSubOverflow32(m.left().Value(), 475 m.right().Value(), &val); 476 return ReplaceInt32((index == 0) ? val : ovf); 477 } 478 if (m.right().Is(0)) { 479 return (index == 0) ? Replace(m.left().node()) : ReplaceInt32(0); 480 } 481 break; 482 } 483 default: 484 break; 485 } 486 return NoChange(); 487} 488 489 490CommonOperatorBuilder* MachineOperatorReducer::common() const { 491 return jsgraph()->common(); 492} 493 494 495MachineOperatorBuilder* MachineOperatorReducer::machine() const { 496 return jsgraph()->machine(); 497} 498 499 500Graph* MachineOperatorReducer::graph() const { return jsgraph()->graph(); } 501 502} // namespace compiler 503} // namespace internal 504} // namespace v8 505