SelectionDAG.cpp revision 4c633e82f6041f452e451904ec0de670e7f143e4
1//===-- SelectionDAG.cpp - Implement the SelectionDAG data structures -----===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This implements the SelectionDAG class. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/CodeGen/SelectionDAG.h" 15#include "llvm/Constants.h" 16#include "llvm/GlobalValue.h" 17#include "llvm/Assembly/Writer.h" 18#include "llvm/CodeGen/MachineBasicBlock.h" 19#include <iostream> 20#include <set> 21#include <cmath> 22#include <algorithm> 23using namespace llvm; 24 25static bool isCommutativeBinOp(unsigned Opcode) { 26 switch (Opcode) { 27 case ISD::ADD: 28 case ISD::MUL: 29 case ISD::AND: 30 case ISD::OR: 31 case ISD::XOR: return true; 32 default: return false; // FIXME: Need commutative info for user ops! 33 } 34} 35 36static bool isAssociativeBinOp(unsigned Opcode) { 37 switch (Opcode) { 38 case ISD::ADD: 39 case ISD::MUL: 40 case ISD::AND: 41 case ISD::OR: 42 case ISD::XOR: return true; 43 default: return false; // FIXME: Need associative info for user ops! 44 } 45} 46 47static unsigned ExactLog2(uint64_t Val) { 48 unsigned Count = 0; 49 while (Val != 1) { 50 Val >>= 1; 51 ++Count; 52 } 53 return Count; 54} 55 56// isInvertibleForFree - Return true if there is no cost to emitting the logical 57// inverse of this node. 58static bool isInvertibleForFree(SDOperand N) { 59 if (isa<ConstantSDNode>(N.Val)) return true; 60 if (isa<SetCCSDNode>(N.Val) && N.Val->hasOneUse()) 61 return true; 62 return false; 63} 64 65 66/// getSetCCSwappedOperands - Return the operation corresponding to (Y op X) 67/// when given the operation for (X op Y). 68ISD::CondCode ISD::getSetCCSwappedOperands(ISD::CondCode Operation) { 69 // To perform this operation, we just need to swap the L and G bits of the 70 // operation. 71 unsigned OldL = (Operation >> 2) & 1; 72 unsigned OldG = (Operation >> 1) & 1; 73 return ISD::CondCode((Operation & ~6) | // Keep the N, U, E bits 74 (OldL << 1) | // New G bit 75 (OldG << 2)); // New L bit. 76} 77 78/// getSetCCInverse - Return the operation corresponding to !(X op Y), where 79/// 'op' is a valid SetCC operation. 80ISD::CondCode ISD::getSetCCInverse(ISD::CondCode Op, bool isInteger) { 81 unsigned Operation = Op; 82 if (isInteger) 83 Operation ^= 7; // Flip L, G, E bits, but not U. 84 else 85 Operation ^= 15; // Flip all of the condition bits. 86 if (Operation > ISD::SETTRUE2) 87 Operation &= ~8; // Don't let N and U bits get set. 88 return ISD::CondCode(Operation); 89} 90 91 92/// isSignedOp - For an integer comparison, return 1 if the comparison is a 93/// signed operation and 2 if the result is an unsigned comparison. Return zero 94/// if the operation does not depend on the sign of the input (setne and seteq). 95static int isSignedOp(ISD::CondCode Opcode) { 96 switch (Opcode) { 97 default: assert(0 && "Illegal integer setcc operation!"); 98 case ISD::SETEQ: 99 case ISD::SETNE: return 0; 100 case ISD::SETLT: 101 case ISD::SETLE: 102 case ISD::SETGT: 103 case ISD::SETGE: return 1; 104 case ISD::SETULT: 105 case ISD::SETULE: 106 case ISD::SETUGT: 107 case ISD::SETUGE: return 2; 108 } 109} 110 111/// getSetCCOrOperation - Return the result of a logical OR between different 112/// comparisons of identical values: ((X op1 Y) | (X op2 Y)). This function 113/// returns SETCC_INVALID if it is not possible to represent the resultant 114/// comparison. 115ISD::CondCode ISD::getSetCCOrOperation(ISD::CondCode Op1, ISD::CondCode Op2, 116 bool isInteger) { 117 if (isInteger && (isSignedOp(Op1) | isSignedOp(Op2)) == 3) 118 // Cannot fold a signed integer setcc with an unsigned integer setcc. 119 return ISD::SETCC_INVALID; 120 121 unsigned Op = Op1 | Op2; // Combine all of the condition bits. 122 123 // If the N and U bits get set then the resultant comparison DOES suddenly 124 // care about orderedness, and is true when ordered. 125 if (Op > ISD::SETTRUE2) 126 Op &= ~16; // Clear the N bit. 127 return ISD::CondCode(Op); 128} 129 130/// getSetCCAndOperation - Return the result of a logical AND between different 131/// comparisons of identical values: ((X op1 Y) & (X op2 Y)). This 132/// function returns zero if it is not possible to represent the resultant 133/// comparison. 134ISD::CondCode ISD::getSetCCAndOperation(ISD::CondCode Op1, ISD::CondCode Op2, 135 bool isInteger) { 136 if (isInteger && (isSignedOp(Op1) | isSignedOp(Op2)) == 3) 137 // Cannot fold a signed setcc with an unsigned setcc. 138 return ISD::SETCC_INVALID; 139 140 // Combine all of the condition bits. 141 return ISD::CondCode(Op1 & Op2); 142} 143 144/// RemoveDeadNodes - This method deletes all unreachable nodes in the 145/// SelectionDAG, including nodes (like loads) that have uses of their token 146/// chain but no other uses and no side effect. If a node is passed in as an 147/// argument, it is used as the seed for node deletion. 148void SelectionDAG::RemoveDeadNodes(SDNode *N) { 149 std::set<SDNode*> AllNodeSet(AllNodes.begin(), AllNodes.end()); 150 151 // Create a dummy node (which is not added to allnodes), that adds a reference 152 // to the root node, preventing it from being deleted. 153 SDNode *DummyNode = new SDNode(ISD::EntryToken, getRoot()); 154 155 DeleteNodeIfDead(N, &AllNodeSet); 156 157 Restart: 158 unsigned NumNodes = AllNodeSet.size(); 159 for (std::set<SDNode*>::iterator I = AllNodeSet.begin(), E = AllNodeSet.end(); 160 I != E; ++I) { 161 // Try to delete this node. 162 DeleteNodeIfDead(*I, &AllNodeSet); 163 164 // If we actually deleted any nodes, do not use invalid iterators in 165 // AllNodeSet. 166 if (AllNodeSet.size() != NumNodes) 167 goto Restart; 168 } 169 170 // Restore AllNodes. 171 if (AllNodes.size() != NumNodes) 172 AllNodes.assign(AllNodeSet.begin(), AllNodeSet.end()); 173 174 // If the root changed (e.g. it was a dead load, update the root). 175 setRoot(DummyNode->getOperand(0)); 176 177 // Now that we are done with the dummy node, delete it. 178 DummyNode->getOperand(0).Val->removeUser(DummyNode); 179 delete DummyNode; 180} 181 182void SelectionDAG::DeleteNodeIfDead(SDNode *N, void *NodeSet) { 183 if (!N->use_empty()) 184 return; 185 186 // Okay, we really are going to delete this node. First take this out of the 187 // appropriate CSE map. 188 switch (N->getOpcode()) { 189 case ISD::Constant: 190 Constants.erase(std::make_pair(cast<ConstantSDNode>(N)->getValue(), 191 N->getValueType(0))); 192 break; 193 case ISD::ConstantFP: 194 ConstantFPs.erase(std::make_pair(cast<ConstantFPSDNode>(N)->getValue(), 195 N->getValueType(0))); 196 break; 197 case ISD::GlobalAddress: 198 GlobalValues.erase(cast<GlobalAddressSDNode>(N)->getGlobal()); 199 break; 200 case ISD::FrameIndex: 201 FrameIndices.erase(cast<FrameIndexSDNode>(N)->getIndex()); 202 break; 203 case ISD::ConstantPool: 204 ConstantPoolIndices.erase(cast<ConstantPoolSDNode>(N)->getIndex()); 205 break; 206 case ISD::BasicBlock: 207 BBNodes.erase(cast<BasicBlockSDNode>(N)->getBasicBlock()); 208 break; 209 case ISD::ExternalSymbol: 210 ExternalSymbols.erase(cast<ExternalSymbolSDNode>(N)->getSymbol()); 211 break; 212 213 case ISD::LOAD: 214 Loads.erase(std::make_pair(N->getOperand(1), 215 std::make_pair(N->getOperand(0), 216 N->getValueType(0)))); 217 break; 218 case ISD::SETCC: 219 SetCCs.erase(std::make_pair(std::make_pair(N->getOperand(0), 220 N->getOperand(1)), 221 cast<SetCCSDNode>(N)->getCondition())); 222 break; 223 default: 224 if (N->getNumOperands() == 1) 225 UnaryOps.erase(std::make_pair(N->getOpcode(), 226 std::make_pair(N->getOperand(0), 227 N->getValueType(0)))); 228 else if (N->getNumOperands() == 2) 229 BinaryOps.erase(std::make_pair(N->getOpcode(), 230 std::make_pair(N->getOperand(0), 231 N->getOperand(1)))); 232 break; 233 } 234 235 // Next, brutally remove the operand list. 236 while (!N->Operands.empty()) { 237 SDNode *O = N->Operands.back().Val; 238 N->Operands.pop_back(); 239 O->removeUser(N); 240 241 // Now that we removed this operand, see if there are no uses of it left. 242 DeleteNodeIfDead(O, NodeSet); 243 } 244 245 // Remove the node from the nodes set and delete it. 246 std::set<SDNode*> &AllNodeSet = *(std::set<SDNode*>*)NodeSet; 247 AllNodeSet.erase(N); 248 249 // Now that the node is gone, check to see if any of the operands of this node 250 // are dead now. 251 delete N; 252} 253 254 255SelectionDAG::~SelectionDAG() { 256 for (unsigned i = 0, e = AllNodes.size(); i != e; ++i) 257 delete AllNodes[i]; 258} 259 260SDOperand SelectionDAG::getConstant(uint64_t Val, MVT::ValueType VT) { 261 assert(MVT::isInteger(VT) && "Cannot create FP integer constant!"); 262 // Mask out any bits that are not valid for this constant. 263 if (VT != MVT::i64) 264 Val &= ((uint64_t)1 << MVT::getSizeInBits(VT)) - 1; 265 266 SDNode *&N = Constants[std::make_pair(Val, VT)]; 267 if (N) return SDOperand(N, 0); 268 N = new ConstantSDNode(Val, VT); 269 AllNodes.push_back(N); 270 return SDOperand(N, 0); 271} 272 273SDOperand SelectionDAG::getConstantFP(double Val, MVT::ValueType VT) { 274 assert(MVT::isFloatingPoint(VT) && "Cannot create integer FP constant!"); 275 if (VT == MVT::f32) 276 Val = (float)Val; // Mask out extra precision. 277 278 SDNode *&N = ConstantFPs[std::make_pair(Val, VT)]; 279 if (N) return SDOperand(N, 0); 280 N = new ConstantFPSDNode(Val, VT); 281 AllNodes.push_back(N); 282 return SDOperand(N, 0); 283} 284 285 286 287SDOperand SelectionDAG::getGlobalAddress(const GlobalValue *GV, 288 MVT::ValueType VT) { 289 SDNode *&N = GlobalValues[GV]; 290 if (N) return SDOperand(N, 0); 291 N = new GlobalAddressSDNode(GV,VT); 292 AllNodes.push_back(N); 293 return SDOperand(N, 0); 294} 295 296SDOperand SelectionDAG::getFrameIndex(int FI, MVT::ValueType VT) { 297 SDNode *&N = FrameIndices[FI]; 298 if (N) return SDOperand(N, 0); 299 N = new FrameIndexSDNode(FI, VT); 300 AllNodes.push_back(N); 301 return SDOperand(N, 0); 302} 303 304SDOperand SelectionDAG::getConstantPool(unsigned CPIdx, MVT::ValueType VT) { 305 SDNode *N = ConstantPoolIndices[CPIdx]; 306 if (N) return SDOperand(N, 0); 307 N = new ConstantPoolSDNode(CPIdx, VT); 308 AllNodes.push_back(N); 309 return SDOperand(N, 0); 310} 311 312SDOperand SelectionDAG::getBasicBlock(MachineBasicBlock *MBB) { 313 SDNode *&N = BBNodes[MBB]; 314 if (N) return SDOperand(N, 0); 315 N = new BasicBlockSDNode(MBB); 316 AllNodes.push_back(N); 317 return SDOperand(N, 0); 318} 319 320SDOperand SelectionDAG::getExternalSymbol(const char *Sym, MVT::ValueType VT) { 321 SDNode *&N = ExternalSymbols[Sym]; 322 if (N) return SDOperand(N, 0); 323 N = new ExternalSymbolSDNode(Sym, VT); 324 AllNodes.push_back(N); 325 return SDOperand(N, 0); 326} 327 328SDOperand SelectionDAG::getSetCC(ISD::CondCode Cond, SDOperand N1, 329 SDOperand N2) { 330 // These setcc operations always fold. 331 switch (Cond) { 332 default: break; 333 case ISD::SETFALSE: 334 case ISD::SETFALSE2: return getConstant(0, MVT::i1); 335 case ISD::SETTRUE: 336 case ISD::SETTRUE2: return getConstant(1, MVT::i1); 337 } 338 339 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) 340 if (ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val)) { 341 uint64_t C1 = N1C->getValue(), C2 = N2C->getValue(); 342 343 // Sign extend the operands if required 344 if (ISD::isSignedIntSetCC(Cond)) { 345 C1 = N1C->getSignExtended(); 346 C2 = N2C->getSignExtended(); 347 } 348 349 switch (Cond) { 350 default: assert(0 && "Unknown integer setcc!"); 351 case ISD::SETEQ: return getConstant(C1 == C2, MVT::i1); 352 case ISD::SETNE: return getConstant(C1 != C2, MVT::i1); 353 case ISD::SETULT: return getConstant(C1 < C2, MVT::i1); 354 case ISD::SETUGT: return getConstant(C1 > C2, MVT::i1); 355 case ISD::SETULE: return getConstant(C1 <= C2, MVT::i1); 356 case ISD::SETUGE: return getConstant(C1 >= C2, MVT::i1); 357 case ISD::SETLT: return getConstant((int64_t)C1 < (int64_t)C2, MVT::i1); 358 case ISD::SETGT: return getConstant((int64_t)C1 > (int64_t)C2, MVT::i1); 359 case ISD::SETLE: return getConstant((int64_t)C1 <= (int64_t)C2, MVT::i1); 360 case ISD::SETGE: return getConstant((int64_t)C1 >= (int64_t)C2, MVT::i1); 361 } 362 } else { 363 // Ensure that the constant occurs on the RHS. 364 Cond = ISD::getSetCCSwappedOperands(Cond); 365 std::swap(N1, N2); 366 } 367 368 if (ConstantFPSDNode *N1C = dyn_cast<ConstantFPSDNode>(N1.Val)) 369 if (ConstantFPSDNode *N2C = dyn_cast<ConstantFPSDNode>(N2.Val)) { 370 double C1 = N1C->getValue(), C2 = N2C->getValue(); 371 372 switch (Cond) { 373 default: break; // FIXME: Implement the rest of these! 374 case ISD::SETEQ: return getConstant(C1 == C2, MVT::i1); 375 case ISD::SETNE: return getConstant(C1 != C2, MVT::i1); 376 case ISD::SETLT: return getConstant((int64_t)C1 < (int64_t)C2, MVT::i1); 377 case ISD::SETGT: return getConstant((int64_t)C1 < (int64_t)C2, MVT::i1); 378 case ISD::SETLE: return getConstant((int64_t)C1 < (int64_t)C2, MVT::i1); 379 case ISD::SETGE: return getConstant((int64_t)C1 < (int64_t)C2, MVT::i1); 380 } 381 } else { 382 // Ensure that the constant occurs on the RHS. 383 Cond = ISD::getSetCCSwappedOperands(Cond); 384 std::swap(N1, N2); 385 } 386 387 if (N1 == N2) { 388 // We can always fold X == Y for integer setcc's. 389 if (MVT::isInteger(N1.getValueType())) 390 return getConstant(ISD::isTrueWhenEqual(Cond), MVT::i1); 391 unsigned UOF = ISD::getUnorderedFlavor(Cond); 392 if (UOF == 2) // FP operators that are undefined on NaNs. 393 return getConstant(ISD::isTrueWhenEqual(Cond), MVT::i1); 394 if (UOF == ISD::isTrueWhenEqual(Cond)) 395 return getConstant(UOF, MVT::i1); 396 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO 397 // if it is not already. 398 Cond = UOF == 0 ? ISD::SETUO : ISD::SETO; 399 } 400 401 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) && 402 MVT::isInteger(N1.getValueType())) { 403 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB || 404 N1.getOpcode() == ISD::XOR) { 405 // Simplify (X+Y) == (X+Z) --> Y == Z 406 if (N1.getOpcode() == N2.getOpcode()) { 407 if (N1.getOperand(0) == N2.getOperand(0)) 408 return getSetCC(Cond, N1.getOperand(1), N2.getOperand(1)); 409 if (N1.getOperand(1) == N2.getOperand(1)) 410 return getSetCC(Cond, N1.getOperand(0), N2.getOperand(0)); 411 if (isCommutativeBinOp(N1.getOpcode())) { 412 // If X op Y == Y op X, try other combinations. 413 if (N1.getOperand(0) == N2.getOperand(1)) 414 return getSetCC(Cond, N1.getOperand(1), N2.getOperand(0)); 415 if (N1.getOperand(1) == N2.getOperand(0)) 416 return getSetCC(Cond, N1.getOperand(1), N2.getOperand(1)); 417 } 418 } 419 420 // Simplify (X+Z) == X --> Z == 0 421 if (N1.getOperand(0) == N2) 422 return getSetCC(Cond, N1.getOperand(1), 423 getConstant(0, N1.getValueType())); 424 if (N1.getOperand(1) == N2) { 425 if (isCommutativeBinOp(N1.getOpcode())) 426 return getSetCC(Cond, N1.getOperand(0), 427 getConstant(0, N1.getValueType())); 428 else { 429 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!"); 430 // (Z-X) == X --> Z == X<<1 431 return getSetCC(Cond, N1.getOperand(0), 432 getNode(ISD::SHL, N2.getValueType(), 433 N2, getConstant(1, MVT::i8))); 434 } 435 } 436 } 437 438 if (N2.getOpcode() == ISD::ADD || N2.getOpcode() == ISD::SUB || 439 N2.getOpcode() == ISD::XOR) { 440 // Simplify X == (X+Z) --> Z == 0 441 if (N2.getOperand(0) == N1) 442 return getSetCC(Cond, N2.getOperand(1), 443 getConstant(0, N2.getValueType())); 444 else if (N2.getOperand(1) == N1) 445 return getSetCC(Cond, N2.getOperand(0), 446 getConstant(0, N2.getValueType())); 447 } 448 } 449 450 SetCCSDNode *&N = SetCCs[std::make_pair(std::make_pair(N1, N2), Cond)]; 451 if (N) return SDOperand(N, 0); 452 N = new SetCCSDNode(Cond, N1, N2); 453 AllNodes.push_back(N); 454 return SDOperand(N, 0); 455} 456 457 458 459/// getNode - Gets or creates the specified node. 460/// 461SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT) { 462 SDNode *N = new SDNode(Opcode, VT); 463 AllNodes.push_back(N); 464 return SDOperand(N, 0); 465} 466 467static const Type *getTypeFor(MVT::ValueType VT) { 468 switch (VT) { 469 default: assert(0 && "Unknown MVT!"); 470 case MVT::i1: return Type::BoolTy; 471 case MVT::i8: return Type::UByteTy; 472 case MVT::i16: return Type::UShortTy; 473 case MVT::i32: return Type::UIntTy; 474 case MVT::i64: return Type::ULongTy; 475 case MVT::f32: return Type::FloatTy; 476 case MVT::f64: return Type::DoubleTy; 477 } 478} 479 480SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, 481 SDOperand Operand) { 482 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Operand.Val)) { 483 uint64_t Val = C->getValue(); 484 switch (Opcode) { 485 default: break; 486 case ISD::SIGN_EXTEND: return getConstant(C->getSignExtended(), VT); 487 case ISD::ZERO_EXTEND: return getConstant(Val, VT); 488 case ISD::TRUNCATE: return getConstant(Val, VT); 489 case ISD::SINT_TO_FP: return getConstantFP(C->getSignExtended(), VT); 490 case ISD::UINT_TO_FP: return getConstantFP(C->getValue(), VT); 491 } 492 } 493 494 if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Operand.Val)) 495 switch (Opcode) { 496 case ISD::FP_ROUND: 497 case ISD::FP_EXTEND: 498 return getConstantFP(C->getValue(), VT); 499 case ISD::FP_TO_SINT: 500 return getConstant((int64_t)C->getValue(), VT); 501 case ISD::FP_TO_UINT: 502 return getConstant((uint64_t)C->getValue(), VT); 503 } 504 505 unsigned OpOpcode = Operand.Val->getOpcode(); 506 switch (Opcode) { 507 case ISD::SIGN_EXTEND: 508 if (Operand.getValueType() == VT) return Operand; // noop extension 509 if (OpOpcode == ISD::SIGN_EXTEND || OpOpcode == ISD::ZERO_EXTEND) 510 return getNode(OpOpcode, VT, Operand.Val->getOperand(0)); 511 break; 512 case ISD::ZERO_EXTEND: 513 if (Operand.getValueType() == VT) return Operand; // noop extension 514 if (OpOpcode == ISD::SIGN_EXTEND || OpOpcode == ISD::ZERO_EXTEND) 515 return getNode(OpOpcode, VT, Operand.Val->getOperand(0)); 516 break; 517 case ISD::TRUNCATE: 518 if (Operand.getValueType() == VT) return Operand; // noop truncate 519 if (OpOpcode == ISD::TRUNCATE) 520 return getNode(ISD::TRUNCATE, VT, Operand.Val->getOperand(0)); 521 else if (OpOpcode == ISD::ZERO_EXTEND || OpOpcode == ISD::SIGN_EXTEND) { 522 // If the source is smaller than the dest, we still need an extend. 523 if (Operand.Val->getOperand(0).getValueType() < VT) 524 return getNode(OpOpcode, VT, Operand.Val->getOperand(0)); 525 else if (Operand.Val->getOperand(0).getValueType() > VT) 526 return getNode(ISD::TRUNCATE, VT, Operand.Val->getOperand(0)); 527 else 528 return Operand.Val->getOperand(0); 529 } 530 break; 531 } 532 533 SDNode *&N = UnaryOps[std::make_pair(Opcode, std::make_pair(Operand, VT))]; 534 if (N) return SDOperand(N, 0); 535 N = new SDNode(Opcode, Operand); 536 N->setValueTypes(VT); 537 AllNodes.push_back(N); 538 return SDOperand(N, 0); 539} 540 541SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, 542 SDOperand N1, SDOperand N2) { 543 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 544 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val); 545 if (N1C) { 546 if (N2C) { 547 uint64_t C1 = N1C->getValue(), C2 = N2C->getValue(); 548 switch (Opcode) { 549 case ISD::ADD: return getConstant(C1 + C2, VT); 550 case ISD::SUB: return getConstant(C1 - C2, VT); 551 case ISD::MUL: return getConstant(C1 * C2, VT); 552 case ISD::UDIV: 553 if (C2) return getConstant(C1 / C2, VT); 554 break; 555 case ISD::UREM : 556 if (C2) return getConstant(C1 % C2, VT); 557 break; 558 case ISD::SDIV : 559 if (C2) return getConstant(N1C->getSignExtended() / 560 N2C->getSignExtended(), VT); 561 break; 562 case ISD::SREM : 563 if (C2) return getConstant(N1C->getSignExtended() % 564 N2C->getSignExtended(), VT); 565 break; 566 case ISD::AND : return getConstant(C1 & C2, VT); 567 case ISD::OR : return getConstant(C1 | C2, VT); 568 case ISD::XOR : return getConstant(C1 ^ C2, VT); 569 case ISD::SHL : return getConstant(C1 << (int)C2, VT); 570 case ISD::SRL : return getConstant(C1 >> (unsigned)C2, VT); 571 case ISD::SRA : return getConstant(N1C->getSignExtended() >>(int)C2, VT); 572 default: break; 573 } 574 575 } else { // Cannonicalize constant to RHS if commutative 576 if (isCommutativeBinOp(Opcode)) { 577 std::swap(N1C, N2C); 578 std::swap(N1, N2); 579 } 580 } 581 } 582 583 if (N2C) { 584 uint64_t C2 = N2C->getValue(); 585 586 switch (Opcode) { 587 case ISD::ADD: 588 if (!C2) return N1; // add X, 0 -> X 589 break; 590 case ISD::SUB: 591 if (!C2) return N1; // sub X, 0 -> X 592 break; 593 case ISD::MUL: 594 if (!C2) return N2; // mul X, 0 -> 0 595 if (N2C->isAllOnesValue()) // mul X, -1 -> 0-X 596 return getNode(ISD::SUB, VT, getConstant(0, VT), N1); 597 598 // FIXME: This should only be done if the target supports shift 599 // operations. 600 if ((C2 & C2-1) == 0) { 601 SDOperand ShAmt = getConstant(ExactLog2(C2), MVT::i8); 602 return getNode(ISD::SHL, VT, N1, ShAmt); 603 } 604 break; 605 606 case ISD::UDIV: 607 // FIXME: This should only be done if the target supports shift 608 // operations. 609 if ((C2 & C2-1) == 0 && C2) { 610 SDOperand ShAmt = getConstant(ExactLog2(C2), MVT::i8); 611 return getNode(ISD::SRL, VT, N1, ShAmt); 612 } 613 break; 614 615 case ISD::SHL: 616 case ISD::SRL: 617 case ISD::SRA: 618 if (C2 == 0) return N1; 619 break; 620 621 case ISD::AND: 622 if (!C2) return N2; // X and 0 -> 0 623 if (N2C->isAllOnesValue()) 624 return N1; // X and -1 -> X 625 break; 626 case ISD::OR: 627 if (!C2)return N1; // X or 0 -> X 628 if (N2C->isAllOnesValue()) 629 return N2; // X or -1 -> -1 630 break; 631 case ISD::XOR: 632 if (!C2) return N1; // X xor 0 -> X 633 if (N2C->isAllOnesValue()) { 634 if (SetCCSDNode *SetCC = dyn_cast<SetCCSDNode>(N1.Val)){ 635 // !(X op Y) -> (X !op Y) 636 bool isInteger = MVT::isInteger(SetCC->getOperand(0).getValueType()); 637 return getSetCC(ISD::getSetCCInverse(SetCC->getCondition(),isInteger), 638 SetCC->getOperand(0), SetCC->getOperand(1)); 639 } else if (N1.getOpcode() == ISD::AND || N1.getOpcode() == ISD::OR) { 640 SDNode *Op = N1.Val; 641 // !(X or Y) -> (!X and !Y) iff X or Y are freely invertible 642 // !(X and Y) -> (!X or !Y) iff X or Y are freely invertible 643 SDOperand LHS = Op->getOperand(0), RHS = Op->getOperand(1); 644 if (isInvertibleForFree(RHS) || isInvertibleForFree(LHS)) { 645 LHS = getNode(ISD::XOR, VT, LHS, N2); // RHS = ~LHS 646 RHS = getNode(ISD::XOR, VT, RHS, N2); // RHS = ~RHS 647 if (Op->getOpcode() == ISD::AND) 648 return getNode(ISD::OR, VT, LHS, RHS); 649 return getNode(ISD::AND, VT, LHS, RHS); 650 } 651 } 652 // X xor -1 -> not(x) ? 653 } 654 break; 655 } 656 657 // Reassociate ((X op C1) op C2) if possible. 658 if (N1.getOpcode() == Opcode && isAssociativeBinOp(Opcode)) 659 if (ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N1.Val->getOperand(1))) 660 return getNode(Opcode, VT, N1.Val->getOperand(0), 661 getNode(Opcode, VT, N2, N1.Val->getOperand(1))); 662 } 663 664 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1.Val); 665 ConstantFPSDNode *N2CFP = dyn_cast<ConstantFPSDNode>(N2.Val); 666 if (N1CFP) 667 if (N2CFP) { 668 double C1 = N1CFP->getValue(), C2 = N2CFP->getValue(); 669 switch (Opcode) { 670 case ISD::ADD: return getConstantFP(C1 + C2, VT); 671 case ISD::SUB: return getConstantFP(C1 - C2, VT); 672 case ISD::MUL: return getConstantFP(C1 * C2, VT); 673 case ISD::SDIV: 674 if (C2) return getConstantFP(C1 / C2, VT); 675 break; 676 case ISD::SREM : 677 if (C2) return getConstantFP(fmod(C1, C2), VT); 678 break; 679 default: break; 680 } 681 682 } else { // Cannonicalize constant to RHS if commutative 683 if (isCommutativeBinOp(Opcode)) { 684 std::swap(N1CFP, N2CFP); 685 std::swap(N1, N2); 686 } 687 } 688 689 // Finally, fold operations that do not require constants. 690 switch (Opcode) { 691 case ISD::AND: 692 case ISD::OR: 693 if (SetCCSDNode *LHS = dyn_cast<SetCCSDNode>(N1.Val)) 694 if (SetCCSDNode *RHS = dyn_cast<SetCCSDNode>(N2.Val)) { 695 SDOperand LL = LHS->getOperand(0), RL = RHS->getOperand(0); 696 SDOperand LR = LHS->getOperand(1), RR = RHS->getOperand(1); 697 ISD::CondCode Op2 = RHS->getCondition(); 698 699 // (X op1 Y) | (Y op2 X) -> (X op1 Y) | (X swapop2 Y) 700 if (LL == RR && LR == RL) { 701 Op2 = ISD::getSetCCSwappedOperands(Op2); 702 goto MatchedBackwards; 703 } 704 705 if (LL == RL && LR == RR) { 706 MatchedBackwards: 707 ISD::CondCode Result; 708 bool isInteger = MVT::isInteger(LL.getValueType()); 709 if (Opcode == ISD::OR) 710 Result = ISD::getSetCCOrOperation(LHS->getCondition(), Op2, 711 isInteger); 712 else 713 Result = ISD::getSetCCAndOperation(LHS->getCondition(), Op2, 714 isInteger); 715 if (Result != ISD::SETCC_INVALID) 716 return getSetCC(Result, LL, LR); 717 } 718 } 719 break; 720 case ISD::XOR: 721 if (N1 == N2) return getConstant(0, VT); // xor X, Y -> 0 722 break; 723 case ISD::SUB: 724 if (N1.getOpcode() == ISD::ADD) { 725 if (N1.Val->getOperand(0) == N2) 726 return N1.Val->getOperand(1); // (A+B)-A == B 727 if (N1.Val->getOperand(1) == N2) 728 return N1.Val->getOperand(0); // (A+B)-B == A 729 } 730 break; 731 } 732 733 SDNode *&N = BinaryOps[std::make_pair(Opcode, std::make_pair(N1, N2))]; 734 if (N) return SDOperand(N, 0); 735 N = new SDNode(Opcode, N1, N2); 736 N->setValueTypes(VT); 737 738 AllNodes.push_back(N); 739 return SDOperand(N, 0); 740} 741 742SDOperand SelectionDAG::getLoad(MVT::ValueType VT, 743 SDOperand Chain, SDOperand Ptr) { 744 SDNode *&N = Loads[std::make_pair(Ptr, std::make_pair(Chain, VT))]; 745 if (N) return SDOperand(N, 0); 746 N = new SDNode(ISD::LOAD, Chain, Ptr); 747 748 // Loads have a token chain. 749 N->setValueTypes(VT, MVT::Other); 750 AllNodes.push_back(N); 751 return SDOperand(N, 0); 752} 753 754 755SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, 756 SDOperand N1, SDOperand N2, SDOperand N3) { 757 // Perform various simplifications. 758 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 759 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val); 760 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val); 761 switch (Opcode) { 762 case ISD::SELECT: 763 if (N1C) 764 if (N1C->getValue()) 765 return N2; // select true, X, Y -> X 766 else 767 return N3; // select false, X, Y -> Y 768 769 if (N2 == N3) return N2; // select C, X, X -> X 770 771 if (VT == MVT::i1) { // Boolean SELECT 772 if (N2C) { 773 if (N3C) { 774 if (N2C->getValue()) // select C, 1, 0 -> C 775 return N1; 776 return getNode(ISD::XOR, VT, N1, N3); // select C, 0, 1 -> ~C 777 } 778 779 if (N2C->getValue()) // select C, 1, X -> C | X 780 return getNode(ISD::OR, VT, N1, N3); 781 else // select C, 0, X -> ~C & X 782 return getNode(ISD::AND, VT, 783 getNode(ISD::XOR, N1.getValueType(), N1, 784 getConstant(1, N1.getValueType())), N3); 785 } else if (N3C) { 786 if (N3C->getValue()) // select C, X, 1 -> ~C | X 787 return getNode(ISD::OR, VT, 788 getNode(ISD::XOR, N1.getValueType(), N1, 789 getConstant(1, N1.getValueType())), N2); 790 else // select C, X, 0 -> C & X 791 return getNode(ISD::AND, VT, N1, N2); 792 } 793 } 794 795 break; 796 case ISD::BRCOND: 797 if (N2C) 798 if (N2C->getValue()) // Unconditional branch 799 return getNode(ISD::BR, MVT::Other, N1, N3); 800 else 801 return N1; // Never-taken branch 802 break; 803 } 804 805 SDNode *N = new SDNode(Opcode, N1, N2, N3); 806 switch (Opcode) { 807 default: 808 N->setValueTypes(VT); 809 break; 810 case ISD::DYNAMIC_STACKALLOC: // DYNAMIC_STACKALLOC produces pointer and chain 811 N->setValueTypes(VT, MVT::Other); 812 break; 813 } 814 815 // FIXME: memoize NODES 816 AllNodes.push_back(N); 817 return SDOperand(N, 0); 818} 819 820SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, 821 std::vector<SDOperand> &Children) { 822 switch (Children.size()) { 823 case 0: return getNode(Opcode, VT); 824 case 1: return getNode(Opcode, VT, Children[0]); 825 case 2: return getNode(Opcode, VT, Children[0], Children[1]); 826 case 3: return getNode(Opcode, VT, Children[0], Children[1], Children[2]); 827 default: 828 // FIXME: MEMOIZE!! 829 SDNode *N = new SDNode(Opcode, Children); 830 N->setValueTypes(VT); 831 AllNodes.push_back(N); 832 return SDOperand(N, 0); 833 } 834} 835 836const char *SDNode::getOperationName() const { 837 switch (getOpcode()) { 838 default: return "<<Unknown>>"; 839 case ISD::EntryToken: return "EntryToken"; 840 case ISD::Constant: return "Constant"; 841 case ISD::ConstantFP: return "ConstantFP"; 842 case ISD::GlobalAddress: return "GlobalAddress"; 843 case ISD::FrameIndex: return "FrameIndex"; 844 case ISD::BasicBlock: return "BasicBlock"; 845 case ISD::ExternalSymbol: return "ExternalSymbol"; 846 case ISD::ConstantPool: return "ConstantPoolIndex"; 847 case ISD::CopyToReg: return "CopyToReg"; 848 case ISD::CopyFromReg: return "CopyFromReg"; 849 850 case ISD::ADD: return "add"; 851 case ISD::SUB: return "sub"; 852 case ISD::MUL: return "mul"; 853 case ISD::SDIV: return "sdiv"; 854 case ISD::UDIV: return "udiv"; 855 case ISD::SREM: return "srem"; 856 case ISD::UREM: return "urem"; 857 case ISD::AND: return "and"; 858 case ISD::OR: return "or"; 859 case ISD::XOR: return "xor"; 860 case ISD::SHL: return "shl"; 861 case ISD::SRA: return "sra"; 862 case ISD::SRL: return "srl"; 863 864 case ISD::SELECT: return "select"; 865 case ISD::ADDC: return "addc"; 866 case ISD::SUBB: return "subb"; 867 868 // Conversion operators. 869 case ISD::SIGN_EXTEND: return "sign_extend"; 870 case ISD::ZERO_EXTEND: return "zero_extend"; 871 case ISD::TRUNCATE: return "truncate"; 872 case ISD::FP_ROUND: return "fp_round"; 873 case ISD::FP_EXTEND: return "fp_extend"; 874 875 case ISD::SINT_TO_FP: return "sint_to_fp"; 876 case ISD::UINT_TO_FP: return "uint_to_fp"; 877 case ISD::FP_TO_SINT: return "fp_to_sint"; 878 case ISD::FP_TO_UINT: return "fp_to_uint"; 879 880 // Control flow instructions 881 case ISD::BR: return "br"; 882 case ISD::BRCOND: return "brcond"; 883 case ISD::RET: return "ret"; 884 case ISD::CALL: return "call"; 885 case ISD::ADJCALLSTACKDOWN: return "adjcallstackdown"; 886 case ISD::ADJCALLSTACKUP: return "adjcallstackup"; 887 888 // Other operators 889 case ISD::LOAD: return "load"; 890 case ISD::STORE: return "store"; 891 case ISD::DYNAMIC_STACKALLOC: return "dynamic_stackalloc"; 892 case ISD::EXTRACT_ELEMENT: return "extract_element"; 893 case ISD::BUILD_PAIR: return "build_pair"; 894 case ISD::MEMSET: return "memset"; 895 case ISD::MEMCPY: return "memcpy"; 896 case ISD::MEMMOVE: return "memmove"; 897 898 case ISD::SETCC: 899 const SetCCSDNode *SetCC = cast<SetCCSDNode>(this); 900 switch (SetCC->getCondition()) { 901 default: assert(0 && "Unknown setcc condition!"); 902 case ISD::SETOEQ: return "setcc:setoeq"; 903 case ISD::SETOGT: return "setcc:setogt"; 904 case ISD::SETOGE: return "setcc:setoge"; 905 case ISD::SETOLT: return "setcc:setolt"; 906 case ISD::SETOLE: return "setcc:setole"; 907 case ISD::SETONE: return "setcc:setone"; 908 909 case ISD::SETO: return "setcc:seto"; 910 case ISD::SETUO: return "setcc:setuo"; 911 case ISD::SETUEQ: return "setcc:setue"; 912 case ISD::SETUGT: return "setcc:setugt"; 913 case ISD::SETUGE: return "setcc:setuge"; 914 case ISD::SETULT: return "setcc:setult"; 915 case ISD::SETULE: return "setcc:setule"; 916 case ISD::SETUNE: return "setcc:setune"; 917 918 case ISD::SETEQ: return "setcc:seteq"; 919 case ISD::SETGT: return "setcc:setgt"; 920 case ISD::SETGE: return "setcc:setge"; 921 case ISD::SETLT: return "setcc:setlt"; 922 case ISD::SETLE: return "setcc:setle"; 923 case ISD::SETNE: return "setcc:setne"; 924 } 925 } 926} 927 928void SDNode::dump() const { 929 std::cerr << (void*)this << ": "; 930 931 for (unsigned i = 0, e = getNumValues(); i != e; ++i) { 932 if (i) std::cerr << ","; 933 switch (getValueType(i)) { 934 default: assert(0 && "Unknown value type!"); 935 case MVT::i1: std::cerr << "i1"; break; 936 case MVT::i8: std::cerr << "i8"; break; 937 case MVT::i16: std::cerr << "i16"; break; 938 case MVT::i32: std::cerr << "i32"; break; 939 case MVT::i64: std::cerr << "i64"; break; 940 case MVT::f32: std::cerr << "f32"; break; 941 case MVT::f64: std::cerr << "f64"; break; 942 case MVT::Other: std::cerr << "ch"; break; 943 } 944 } 945 std::cerr << " = " << getOperationName(); 946 947 std::cerr << " "; 948 for (unsigned i = 0, e = getNumOperands(); i != e; ++i) { 949 if (i) std::cerr << ", "; 950 std::cerr << (void*)getOperand(i).Val; 951 if (unsigned RN = getOperand(i).ResNo) 952 std::cerr << ":" << RN; 953 } 954 955 if (const ConstantSDNode *CSDN = dyn_cast<ConstantSDNode>(this)) { 956 std::cerr << "<" << CSDN->getValue() << ">"; 957 } else if (const ConstantFPSDNode *CSDN = dyn_cast<ConstantFPSDNode>(this)) { 958 std::cerr << "<" << CSDN->getValue() << ">"; 959 } else if (const GlobalAddressSDNode *GADN = 960 dyn_cast<GlobalAddressSDNode>(this)) { 961 std::cerr << "<"; 962 WriteAsOperand(std::cerr, GADN->getGlobal()) << ">"; 963 } else if (const FrameIndexSDNode *FIDN = 964 dyn_cast<FrameIndexSDNode>(this)) { 965 std::cerr << "<" << FIDN->getIndex() << ">"; 966 } else if (const ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(this)){ 967 std::cerr << "<" << CP->getIndex() << ">"; 968 } else if (const BasicBlockSDNode *BBDN = 969 dyn_cast<BasicBlockSDNode>(this)) { 970 std::cerr << "<"; 971 const Value *LBB = (const Value*)BBDN->getBasicBlock()->getBasicBlock(); 972 if (LBB) 973 std::cerr << LBB->getName() << " "; 974 std::cerr << (const void*)BBDN->getBasicBlock() << ">"; 975 } else if (const CopyRegSDNode *C2V = dyn_cast<CopyRegSDNode>(this)) { 976 std::cerr << "<reg #" << C2V->getReg() << ">"; 977 } else if (const ExternalSymbolSDNode *ES = 978 dyn_cast<ExternalSymbolSDNode>(this)) { 979 std::cerr << "'" << ES->getSymbol() << "'"; 980 } 981} 982 983static void DumpNodes(SDNode *N, unsigned indent) { 984 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 985 if (N->getOperand(i).Val->hasOneUse()) 986 DumpNodes(N->getOperand(i).Val, indent+2); 987 else 988 std::cerr << "\n" << std::string(indent+2, ' ') 989 << (void*)N->getOperand(i).Val << ": <multiple use>"; 990 991 992 std::cerr << "\n" << std::string(indent, ' '); 993 N->dump(); 994} 995 996void SelectionDAG::dump() const { 997 std::cerr << "SelectionDAG has " << AllNodes.size() << " nodes:"; 998 std::vector<SDNode*> Nodes(AllNodes); 999 std::sort(Nodes.begin(), Nodes.end()); 1000 1001 for (unsigned i = 0, e = Nodes.size(); i != e; ++i) { 1002 if (!Nodes[i]->hasOneUse() && Nodes[i] != getRoot().Val) 1003 DumpNodes(Nodes[i], 2); 1004 } 1005 1006 DumpNodes(getRoot().Val, 2); 1007 1008 std::cerr << "\n\n"; 1009} 1010 1011