DAGCombiner.cpp revision 95a5e0507e07fa3ef7c61aade9eb0efd1d716a25
1//===-- DAGCombiner.cpp - Implement a DAG node combiner -------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by Nate Begeman and is distributed under the 6// University of Illinois Open Source License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This pass combines dag nodes to form fewer, simpler DAG nodes. It can be run 11// both before and after the DAG is legalized. 12// 13// FIXME: Missing folds 14// sdiv, udiv, srem, urem (X, const) where X is an integer can be expanded into 15// a sequence of multiplies, shifts, and adds. This should be controlled by 16// some kind of hint from the target that int div is expensive. 17// various folds of mulh[s,u] by constants such as -1, powers of 2, etc. 18// 19// FIXME: select C, pow2, pow2 -> something smart 20// FIXME: trunc(select X, Y, Z) -> select X, trunc(Y), trunc(Z) 21// FIXME: Dead stores -> nuke 22// FIXME: shr X, (and Y,31) -> shr X, Y (TRICKY!) 23// FIXME: mul (x, const) -> shifts + adds 24// FIXME: undef values 25// FIXME: divide by zero is currently left unfolded. do we want to turn this 26// into an undef? 27// FIXME: select ne (select cc, 1, 0), 0, true, false -> select cc, true, false 28// 29//===----------------------------------------------------------------------===// 30 31#define DEBUG_TYPE "dagcombine" 32#include "llvm/ADT/Statistic.h" 33#include "llvm/Analysis/AliasAnalysis.h" 34#include "llvm/CodeGen/SelectionDAG.h" 35#include "llvm/Support/Debug.h" 36#include "llvm/Support/MathExtras.h" 37#include "llvm/Target/TargetLowering.h" 38#include "llvm/Target/TargetOptions.h" 39#include "llvm/Support/Compiler.h" 40#include "llvm/Support/CommandLine.h" 41#include <algorithm> 42using namespace llvm; 43 44STATISTIC(NodesCombined , "Number of dag nodes combined"); 45STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created"); 46STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created"); 47 48namespace { 49#ifndef NDEBUG 50 static cl::opt<bool> 51 ViewDAGCombine1("view-dag-combine1-dags", cl::Hidden, 52 cl::desc("Pop up a window to show dags before the first " 53 "dag combine pass")); 54 static cl::opt<bool> 55 ViewDAGCombine2("view-dag-combine2-dags", cl::Hidden, 56 cl::desc("Pop up a window to show dags before the second " 57 "dag combine pass")); 58#else 59 static const bool ViewDAGCombine1 = false; 60 static const bool ViewDAGCombine2 = false; 61#endif 62 63 static cl::opt<bool> 64 CombinerAA("combiner-alias-analysis", cl::Hidden, 65 cl::desc("Turn on alias analysis during testing")); 66 67 static cl::opt<bool> 68 CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden, 69 cl::desc("Include global information in alias analysis")); 70 71//------------------------------ DAGCombiner ---------------------------------// 72 73 class VISIBILITY_HIDDEN DAGCombiner { 74 SelectionDAG &DAG; 75 TargetLowering &TLI; 76 bool AfterLegalize; 77 78 // Worklist of all of the nodes that need to be simplified. 79 std::vector<SDNode*> WorkList; 80 81 // AA - Used for DAG load/store alias analysis. 82 AliasAnalysis &AA; 83 84 /// AddUsersToWorkList - When an instruction is simplified, add all users of 85 /// the instruction to the work lists because they might get more simplified 86 /// now. 87 /// 88 void AddUsersToWorkList(SDNode *N) { 89 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 90 UI != UE; ++UI) 91 AddToWorkList(*UI); 92 } 93 94 /// removeFromWorkList - remove all instances of N from the worklist. 95 /// 96 void removeFromWorkList(SDNode *N) { 97 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N), 98 WorkList.end()); 99 } 100 101 public: 102 /// AddToWorkList - Add to the work list making sure it's instance is at the 103 /// the back (next to be processed.) 104 void AddToWorkList(SDNode *N) { 105 removeFromWorkList(N); 106 WorkList.push_back(N); 107 } 108 109 SDOperand CombineTo(SDNode *N, const SDOperand *To, unsigned NumTo, 110 bool AddTo = true) { 111 assert(N->getNumValues() == NumTo && "Broken CombineTo call!"); 112 ++NodesCombined; 113 DOUT << "\nReplacing.1 "; DEBUG(N->dump()); 114 DOUT << "\nWith: "; DEBUG(To[0].Val->dump(&DAG)); 115 DOUT << " and " << NumTo-1 << " other values\n"; 116 std::vector<SDNode*> NowDead; 117 DAG.ReplaceAllUsesWith(N, To, &NowDead); 118 119 if (AddTo) { 120 // Push the new nodes and any users onto the worklist 121 for (unsigned i = 0, e = NumTo; i != e; ++i) { 122 AddToWorkList(To[i].Val); 123 AddUsersToWorkList(To[i].Val); 124 } 125 } 126 127 // Nodes can be reintroduced into the worklist. Make sure we do not 128 // process a node that has been replaced. 129 removeFromWorkList(N); 130 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 131 removeFromWorkList(NowDead[i]); 132 133 // Finally, since the node is now dead, remove it from the graph. 134 DAG.DeleteNode(N); 135 return SDOperand(N, 0); 136 } 137 138 SDOperand CombineTo(SDNode *N, SDOperand Res, bool AddTo = true) { 139 return CombineTo(N, &Res, 1, AddTo); 140 } 141 142 SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1, 143 bool AddTo = true) { 144 SDOperand To[] = { Res0, Res1 }; 145 return CombineTo(N, To, 2, AddTo); 146 } 147 private: 148 149 /// SimplifyDemandedBits - Check the specified integer node value to see if 150 /// it can be simplified or if things it uses can be simplified by bit 151 /// propagation. If so, return true. 152 bool SimplifyDemandedBits(SDOperand Op) { 153 TargetLowering::TargetLoweringOpt TLO(DAG); 154 uint64_t KnownZero, KnownOne; 155 uint64_t Demanded = MVT::getIntVTBitMask(Op.getValueType()); 156 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO)) 157 return false; 158 159 // Revisit the node. 160 AddToWorkList(Op.Val); 161 162 // Replace the old value with the new one. 163 ++NodesCombined; 164 DOUT << "\nReplacing.2 "; DEBUG(TLO.Old.Val->dump()); 165 DOUT << "\nWith: "; DEBUG(TLO.New.Val->dump(&DAG)); 166 DOUT << '\n'; 167 168 std::vector<SDNode*> NowDead; 169 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, NowDead); 170 171 // Push the new node and any (possibly new) users onto the worklist. 172 AddToWorkList(TLO.New.Val); 173 AddUsersToWorkList(TLO.New.Val); 174 175 // Nodes can end up on the worklist more than once. Make sure we do 176 // not process a node that has been replaced. 177 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 178 removeFromWorkList(NowDead[i]); 179 180 // Finally, if the node is now dead, remove it from the graph. The node 181 // may not be dead if the replacement process recursively simplified to 182 // something else needing this node. 183 if (TLO.Old.Val->use_empty()) { 184 removeFromWorkList(TLO.Old.Val); 185 DAG.DeleteNode(TLO.Old.Val); 186 } 187 return true; 188 } 189 190 bool CombineToPreIndexedLoadStore(SDNode *N); 191 bool CombineToPostIndexedLoadStore(SDNode *N); 192 193 194 /// visit - call the node-specific routine that knows how to fold each 195 /// particular type of node. 196 SDOperand visit(SDNode *N); 197 198 // Visitation implementation - Implement dag node combining for different 199 // node types. The semantics are as follows: 200 // Return Value: 201 // SDOperand.Val == 0 - No change was made 202 // SDOperand.Val == N - N was replaced, is dead, and is already handled. 203 // otherwise - N should be replaced by the returned Operand. 204 // 205 SDOperand visitTokenFactor(SDNode *N); 206 SDOperand visitADD(SDNode *N); 207 SDOperand visitSUB(SDNode *N); 208 SDOperand visitADDC(SDNode *N); 209 SDOperand visitADDE(SDNode *N); 210 SDOperand visitMUL(SDNode *N); 211 SDOperand visitSDIV(SDNode *N); 212 SDOperand visitUDIV(SDNode *N); 213 SDOperand visitSREM(SDNode *N); 214 SDOperand visitUREM(SDNode *N); 215 SDOperand visitMULHU(SDNode *N); 216 SDOperand visitMULHS(SDNode *N); 217 SDOperand visitAND(SDNode *N); 218 SDOperand visitOR(SDNode *N); 219 SDOperand visitXOR(SDNode *N); 220 SDOperand visitVBinOp(SDNode *N, ISD::NodeType IntOp, ISD::NodeType FPOp); 221 SDOperand visitSHL(SDNode *N); 222 SDOperand visitSRA(SDNode *N); 223 SDOperand visitSRL(SDNode *N); 224 SDOperand visitCTLZ(SDNode *N); 225 SDOperand visitCTTZ(SDNode *N); 226 SDOperand visitCTPOP(SDNode *N); 227 SDOperand visitSELECT(SDNode *N); 228 SDOperand visitSELECT_CC(SDNode *N); 229 SDOperand visitSETCC(SDNode *N); 230 SDOperand visitSIGN_EXTEND(SDNode *N); 231 SDOperand visitZERO_EXTEND(SDNode *N); 232 SDOperand visitANY_EXTEND(SDNode *N); 233 SDOperand visitSIGN_EXTEND_INREG(SDNode *N); 234 SDOperand visitTRUNCATE(SDNode *N); 235 SDOperand visitBIT_CONVERT(SDNode *N); 236 SDOperand visitVBIT_CONVERT(SDNode *N); 237 SDOperand visitFADD(SDNode *N); 238 SDOperand visitFSUB(SDNode *N); 239 SDOperand visitFMUL(SDNode *N); 240 SDOperand visitFDIV(SDNode *N); 241 SDOperand visitFREM(SDNode *N); 242 SDOperand visitFCOPYSIGN(SDNode *N); 243 SDOperand visitSINT_TO_FP(SDNode *N); 244 SDOperand visitUINT_TO_FP(SDNode *N); 245 SDOperand visitFP_TO_SINT(SDNode *N); 246 SDOperand visitFP_TO_UINT(SDNode *N); 247 SDOperand visitFP_ROUND(SDNode *N); 248 SDOperand visitFP_ROUND_INREG(SDNode *N); 249 SDOperand visitFP_EXTEND(SDNode *N); 250 SDOperand visitFNEG(SDNode *N); 251 SDOperand visitFABS(SDNode *N); 252 SDOperand visitBRCOND(SDNode *N); 253 SDOperand visitBR_CC(SDNode *N); 254 SDOperand visitLOAD(SDNode *N); 255 SDOperand visitSTORE(SDNode *N); 256 SDOperand visitINSERT_VECTOR_ELT(SDNode *N); 257 SDOperand visitVINSERT_VECTOR_ELT(SDNode *N); 258 SDOperand visitVBUILD_VECTOR(SDNode *N); 259 SDOperand visitVECTOR_SHUFFLE(SDNode *N); 260 SDOperand visitVVECTOR_SHUFFLE(SDNode *N); 261 262 SDOperand XformToShuffleWithZero(SDNode *N); 263 SDOperand ReassociateOps(unsigned Opc, SDOperand LHS, SDOperand RHS); 264 265 bool SimplifySelectOps(SDNode *SELECT, SDOperand LHS, SDOperand RHS); 266 SDOperand SimplifyBinOpWithSameOpcodeHands(SDNode *N); 267 SDOperand SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2); 268 SDOperand SimplifySelectCC(SDOperand N0, SDOperand N1, SDOperand N2, 269 SDOperand N3, ISD::CondCode CC, 270 bool NotExtCompare = false); 271 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1, 272 ISD::CondCode Cond, bool foldBooleans = true); 273 SDOperand ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *, MVT::ValueType); 274 SDOperand BuildSDIV(SDNode *N); 275 SDOperand BuildUDIV(SDNode *N); 276 SDNode *MatchRotate(SDOperand LHS, SDOperand RHS); 277 SDOperand ReduceLoadWidth(SDNode *N); 278 279 /// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, 280 /// looking for aliasing nodes and adding them to the Aliases vector. 281 void GatherAllAliases(SDNode *N, SDOperand OriginalChain, 282 SmallVector<SDOperand, 8> &Aliases); 283 284 /// isAlias - Return true if there is any possibility that the two addresses 285 /// overlap. 286 bool isAlias(SDOperand Ptr1, int64_t Size1, 287 const Value *SrcValue1, int SrcValueOffset1, 288 SDOperand Ptr2, int64_t Size2, 289 const Value *SrcValue2, int SrcValueOffset2); 290 291 /// FindAliasInfo - Extracts the relevant alias information from the memory 292 /// node. Returns true if the operand was a load. 293 bool FindAliasInfo(SDNode *N, 294 SDOperand &Ptr, int64_t &Size, 295 const Value *&SrcValue, int &SrcValueOffset); 296 297 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, 298 /// looking for a better chain (aliasing node.) 299 SDOperand FindBetterChain(SDNode *N, SDOperand Chain); 300 301public: 302 DAGCombiner(SelectionDAG &D, AliasAnalysis &A) 303 : DAG(D), 304 TLI(D.getTargetLoweringInfo()), 305 AfterLegalize(false), 306 AA(A) {} 307 308 /// Run - runs the dag combiner on all nodes in the work list 309 void Run(bool RunningAfterLegalize); 310 }; 311} 312 313//===----------------------------------------------------------------------===// 314// TargetLowering::DAGCombinerInfo implementation 315//===----------------------------------------------------------------------===// 316 317void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) { 318 ((DAGCombiner*)DC)->AddToWorkList(N); 319} 320 321SDOperand TargetLowering::DAGCombinerInfo:: 322CombineTo(SDNode *N, const std::vector<SDOperand> &To) { 323 return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size()); 324} 325 326SDOperand TargetLowering::DAGCombinerInfo:: 327CombineTo(SDNode *N, SDOperand Res) { 328 return ((DAGCombiner*)DC)->CombineTo(N, Res); 329} 330 331 332SDOperand TargetLowering::DAGCombinerInfo:: 333CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) { 334 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1); 335} 336 337 338 339 340//===----------------------------------------------------------------------===// 341 342 343// isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc 344// that selects between the values 1 and 0, making it equivalent to a setcc. 345// Also, set the incoming LHS, RHS, and CC references to the appropriate 346// nodes based on the type of node we are checking. This simplifies life a 347// bit for the callers. 348static bool isSetCCEquivalent(SDOperand N, SDOperand &LHS, SDOperand &RHS, 349 SDOperand &CC) { 350 if (N.getOpcode() == ISD::SETCC) { 351 LHS = N.getOperand(0); 352 RHS = N.getOperand(1); 353 CC = N.getOperand(2); 354 return true; 355 } 356 if (N.getOpcode() == ISD::SELECT_CC && 357 N.getOperand(2).getOpcode() == ISD::Constant && 358 N.getOperand(3).getOpcode() == ISD::Constant && 359 cast<ConstantSDNode>(N.getOperand(2))->getValue() == 1 && 360 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) { 361 LHS = N.getOperand(0); 362 RHS = N.getOperand(1); 363 CC = N.getOperand(4); 364 return true; 365 } 366 return false; 367} 368 369// isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only 370// one use. If this is true, it allows the users to invert the operation for 371// free when it is profitable to do so. 372static bool isOneUseSetCC(SDOperand N) { 373 SDOperand N0, N1, N2; 374 if (isSetCCEquivalent(N, N0, N1, N2) && N.Val->hasOneUse()) 375 return true; 376 return false; 377} 378 379SDOperand DAGCombiner::ReassociateOps(unsigned Opc, SDOperand N0, SDOperand N1){ 380 MVT::ValueType VT = N0.getValueType(); 381 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use 382 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2)) 383 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) { 384 if (isa<ConstantSDNode>(N1)) { 385 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(1), N1); 386 AddToWorkList(OpNode.Val); 387 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(0)); 388 } else if (N0.hasOneUse()) { 389 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(0), N1); 390 AddToWorkList(OpNode.Val); 391 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(1)); 392 } 393 } 394 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use 395 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2)) 396 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) { 397 if (isa<ConstantSDNode>(N0)) { 398 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(1), N0); 399 AddToWorkList(OpNode.Val); 400 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(0)); 401 } else if (N1.hasOneUse()) { 402 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(0), N0); 403 AddToWorkList(OpNode.Val); 404 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(1)); 405 } 406 } 407 return SDOperand(); 408} 409 410void DAGCombiner::Run(bool RunningAfterLegalize) { 411 // set the instance variable, so that the various visit routines may use it. 412 AfterLegalize = RunningAfterLegalize; 413 414 // Add all the dag nodes to the worklist. 415 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 416 E = DAG.allnodes_end(); I != E; ++I) 417 WorkList.push_back(I); 418 419 // Create a dummy node (which is not added to allnodes), that adds a reference 420 // to the root node, preventing it from being deleted, and tracking any 421 // changes of the root. 422 HandleSDNode Dummy(DAG.getRoot()); 423 424 // The root of the dag may dangle to deleted nodes until the dag combiner is 425 // done. Set it to null to avoid confusion. 426 DAG.setRoot(SDOperand()); 427 428 /// DagCombineInfo - Expose the DAG combiner to the target combiner impls. 429 TargetLowering::DAGCombinerInfo 430 DagCombineInfo(DAG, !RunningAfterLegalize, false, this); 431 432 // while the worklist isn't empty, inspect the node on the end of it and 433 // try and combine it. 434 while (!WorkList.empty()) { 435 SDNode *N = WorkList.back(); 436 WorkList.pop_back(); 437 438 // If N has no uses, it is dead. Make sure to revisit all N's operands once 439 // N is deleted from the DAG, since they too may now be dead or may have a 440 // reduced number of uses, allowing other xforms. 441 if (N->use_empty() && N != &Dummy) { 442 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 443 AddToWorkList(N->getOperand(i).Val); 444 445 DAG.DeleteNode(N); 446 continue; 447 } 448 449 SDOperand RV = visit(N); 450 451 // If nothing happened, try a target-specific DAG combine. 452 if (RV.Val == 0) { 453 assert(N->getOpcode() != ISD::DELETED_NODE && 454 "Node was deleted but visit returned NULL!"); 455 if (N->getOpcode() >= ISD::BUILTIN_OP_END || 456 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) 457 RV = TLI.PerformDAGCombine(N, DagCombineInfo); 458 } 459 460 if (RV.Val) { 461 ++NodesCombined; 462 // If we get back the same node we passed in, rather than a new node or 463 // zero, we know that the node must have defined multiple values and 464 // CombineTo was used. Since CombineTo takes care of the worklist 465 // mechanics for us, we have no work to do in this case. 466 if (RV.Val != N) { 467 assert(N->getOpcode() != ISD::DELETED_NODE && 468 RV.Val->getOpcode() != ISD::DELETED_NODE && 469 "Node was deleted but visit returned new node!"); 470 471 DOUT << "\nReplacing.3 "; DEBUG(N->dump()); 472 DOUT << "\nWith: "; DEBUG(RV.Val->dump(&DAG)); 473 DOUT << '\n'; 474 std::vector<SDNode*> NowDead; 475 if (N->getNumValues() == RV.Val->getNumValues()) 476 DAG.ReplaceAllUsesWith(N, RV.Val, &NowDead); 477 else { 478 assert(N->getValueType(0) == RV.getValueType() && "Type mismatch"); 479 SDOperand OpV = RV; 480 DAG.ReplaceAllUsesWith(N, &OpV, &NowDead); 481 } 482 483 // Push the new node and any users onto the worklist 484 AddToWorkList(RV.Val); 485 AddUsersToWorkList(RV.Val); 486 487 // Nodes can be reintroduced into the worklist. Make sure we do not 488 // process a node that has been replaced. 489 removeFromWorkList(N); 490 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 491 removeFromWorkList(NowDead[i]); 492 493 // Finally, since the node is now dead, remove it from the graph. 494 DAG.DeleteNode(N); 495 } 496 } 497 } 498 499 // If the root changed (e.g. it was a dead load, update the root). 500 DAG.setRoot(Dummy.getValue()); 501} 502 503SDOperand DAGCombiner::visit(SDNode *N) { 504 switch(N->getOpcode()) { 505 default: break; 506 case ISD::TokenFactor: return visitTokenFactor(N); 507 case ISD::ADD: return visitADD(N); 508 case ISD::SUB: return visitSUB(N); 509 case ISD::ADDC: return visitADDC(N); 510 case ISD::ADDE: return visitADDE(N); 511 case ISD::MUL: return visitMUL(N); 512 case ISD::SDIV: return visitSDIV(N); 513 case ISD::UDIV: return visitUDIV(N); 514 case ISD::SREM: return visitSREM(N); 515 case ISD::UREM: return visitUREM(N); 516 case ISD::MULHU: return visitMULHU(N); 517 case ISD::MULHS: return visitMULHS(N); 518 case ISD::AND: return visitAND(N); 519 case ISD::OR: return visitOR(N); 520 case ISD::XOR: return visitXOR(N); 521 case ISD::SHL: return visitSHL(N); 522 case ISD::SRA: return visitSRA(N); 523 case ISD::SRL: return visitSRL(N); 524 case ISD::CTLZ: return visitCTLZ(N); 525 case ISD::CTTZ: return visitCTTZ(N); 526 case ISD::CTPOP: return visitCTPOP(N); 527 case ISD::SELECT: return visitSELECT(N); 528 case ISD::SELECT_CC: return visitSELECT_CC(N); 529 case ISD::SETCC: return visitSETCC(N); 530 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N); 531 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N); 532 case ISD::ANY_EXTEND: return visitANY_EXTEND(N); 533 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N); 534 case ISD::TRUNCATE: return visitTRUNCATE(N); 535 case ISD::BIT_CONVERT: return visitBIT_CONVERT(N); 536 case ISD::VBIT_CONVERT: return visitVBIT_CONVERT(N); 537 case ISD::FADD: return visitFADD(N); 538 case ISD::FSUB: return visitFSUB(N); 539 case ISD::FMUL: return visitFMUL(N); 540 case ISD::FDIV: return visitFDIV(N); 541 case ISD::FREM: return visitFREM(N); 542 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N); 543 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N); 544 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N); 545 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N); 546 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N); 547 case ISD::FP_ROUND: return visitFP_ROUND(N); 548 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N); 549 case ISD::FP_EXTEND: return visitFP_EXTEND(N); 550 case ISD::FNEG: return visitFNEG(N); 551 case ISD::FABS: return visitFABS(N); 552 case ISD::BRCOND: return visitBRCOND(N); 553 case ISD::BR_CC: return visitBR_CC(N); 554 case ISD::LOAD: return visitLOAD(N); 555 case ISD::STORE: return visitSTORE(N); 556 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N); 557 case ISD::VINSERT_VECTOR_ELT: return visitVINSERT_VECTOR_ELT(N); 558 case ISD::VBUILD_VECTOR: return visitVBUILD_VECTOR(N); 559 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); 560 case ISD::VVECTOR_SHUFFLE: return visitVVECTOR_SHUFFLE(N); 561 case ISD::VADD: return visitVBinOp(N, ISD::ADD , ISD::FADD); 562 case ISD::VSUB: return visitVBinOp(N, ISD::SUB , ISD::FSUB); 563 case ISD::VMUL: return visitVBinOp(N, ISD::MUL , ISD::FMUL); 564 case ISD::VSDIV: return visitVBinOp(N, ISD::SDIV, ISD::FDIV); 565 case ISD::VUDIV: return visitVBinOp(N, ISD::UDIV, ISD::UDIV); 566 case ISD::VAND: return visitVBinOp(N, ISD::AND , ISD::AND); 567 case ISD::VOR: return visitVBinOp(N, ISD::OR , ISD::OR); 568 case ISD::VXOR: return visitVBinOp(N, ISD::XOR , ISD::XOR); 569 } 570 return SDOperand(); 571} 572 573/// getInputChainForNode - Given a node, return its input chain if it has one, 574/// otherwise return a null sd operand. 575static SDOperand getInputChainForNode(SDNode *N) { 576 if (unsigned NumOps = N->getNumOperands()) { 577 if (N->getOperand(0).getValueType() == MVT::Other) 578 return N->getOperand(0); 579 else if (N->getOperand(NumOps-1).getValueType() == MVT::Other) 580 return N->getOperand(NumOps-1); 581 for (unsigned i = 1; i < NumOps-1; ++i) 582 if (N->getOperand(i).getValueType() == MVT::Other) 583 return N->getOperand(i); 584 } 585 return SDOperand(0, 0); 586} 587 588SDOperand DAGCombiner::visitTokenFactor(SDNode *N) { 589 // If N has two operands, where one has an input chain equal to the other, 590 // the 'other' chain is redundant. 591 if (N->getNumOperands() == 2) { 592 if (getInputChainForNode(N->getOperand(0).Val) == N->getOperand(1)) 593 return N->getOperand(0); 594 if (getInputChainForNode(N->getOperand(1).Val) == N->getOperand(0)) 595 return N->getOperand(1); 596 } 597 598 599 SmallVector<SDNode *, 8> TFs; // List of token factors to visit. 600 SmallVector<SDOperand, 8> Ops; // Ops for replacing token factor. 601 bool Changed = false; // If we should replace this token factor. 602 603 // Start out with this token factor. 604 TFs.push_back(N); 605 606 // Iterate through token factors. The TFs grows when new token factors are 607 // encountered. 608 for (unsigned i = 0; i < TFs.size(); ++i) { 609 SDNode *TF = TFs[i]; 610 611 // Check each of the operands. 612 for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) { 613 SDOperand Op = TF->getOperand(i); 614 615 switch (Op.getOpcode()) { 616 case ISD::EntryToken: 617 // Entry tokens don't need to be added to the list. They are 618 // rededundant. 619 Changed = true; 620 break; 621 622 case ISD::TokenFactor: 623 if ((CombinerAA || Op.hasOneUse()) && 624 std::find(TFs.begin(), TFs.end(), Op.Val) == TFs.end()) { 625 // Queue up for processing. 626 TFs.push_back(Op.Val); 627 // Clean up in case the token factor is removed. 628 AddToWorkList(Op.Val); 629 Changed = true; 630 break; 631 } 632 // Fall thru 633 634 default: 635 // Only add if not there prior. 636 if (std::find(Ops.begin(), Ops.end(), Op) == Ops.end()) 637 Ops.push_back(Op); 638 break; 639 } 640 } 641 } 642 643 SDOperand Result; 644 645 // If we've change things around then replace token factor. 646 if (Changed) { 647 if (Ops.size() == 0) { 648 // The entry token is the only possible outcome. 649 Result = DAG.getEntryNode(); 650 } else { 651 // New and improved token factor. 652 Result = DAG.getNode(ISD::TokenFactor, MVT::Other, &Ops[0], Ops.size()); 653 } 654 655 // Don't add users to work list. 656 return CombineTo(N, Result, false); 657 } 658 659 return Result; 660} 661 662static 663SDOperand combineShlAddConstant(SDOperand N0, SDOperand N1, SelectionDAG &DAG) { 664 MVT::ValueType VT = N0.getValueType(); 665 SDOperand N00 = N0.getOperand(0); 666 SDOperand N01 = N0.getOperand(1); 667 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01); 668 if (N01C && N00.getOpcode() == ISD::ADD && N00.Val->hasOneUse() && 669 isa<ConstantSDNode>(N00.getOperand(1))) { 670 N0 = DAG.getNode(ISD::ADD, VT, 671 DAG.getNode(ISD::SHL, VT, N00.getOperand(0), N01), 672 DAG.getNode(ISD::SHL, VT, N00.getOperand(1), N01)); 673 return DAG.getNode(ISD::ADD, VT, N0, N1); 674 } 675 return SDOperand(); 676} 677 678SDOperand DAGCombiner::visitADD(SDNode *N) { 679 SDOperand N0 = N->getOperand(0); 680 SDOperand N1 = N->getOperand(1); 681 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 682 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 683 MVT::ValueType VT = N0.getValueType(); 684 685 // fold (add c1, c2) -> c1+c2 686 if (N0C && N1C) 687 return DAG.getNode(ISD::ADD, VT, N0, N1); 688 // canonicalize constant to RHS 689 if (N0C && !N1C) 690 return DAG.getNode(ISD::ADD, VT, N1, N0); 691 // fold (add x, 0) -> x 692 if (N1C && N1C->isNullValue()) 693 return N0; 694 // fold ((c1-A)+c2) -> (c1+c2)-A 695 if (N1C && N0.getOpcode() == ISD::SUB) 696 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0))) 697 return DAG.getNode(ISD::SUB, VT, 698 DAG.getConstant(N1C->getValue()+N0C->getValue(), VT), 699 N0.getOperand(1)); 700 // reassociate add 701 SDOperand RADD = ReassociateOps(ISD::ADD, N0, N1); 702 if (RADD.Val != 0) 703 return RADD; 704 // fold ((0-A) + B) -> B-A 705 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) && 706 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue()) 707 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1)); 708 // fold (A + (0-B)) -> A-B 709 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) && 710 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue()) 711 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1)); 712 // fold (A+(B-A)) -> B 713 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1)) 714 return N1.getOperand(0); 715 716 if (!MVT::isVector(VT) && SimplifyDemandedBits(SDOperand(N, 0))) 717 return SDOperand(N, 0); 718 719 // fold (a+b) -> (a|b) iff a and b share no bits. 720 if (MVT::isInteger(VT) && !MVT::isVector(VT)) { 721 uint64_t LHSZero, LHSOne; 722 uint64_t RHSZero, RHSOne; 723 uint64_t Mask = MVT::getIntVTBitMask(VT); 724 TLI.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 725 if (LHSZero) { 726 TLI.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 727 728 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 729 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 730 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 731 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 732 return DAG.getNode(ISD::OR, VT, N0, N1); 733 } 734 } 735 736 // fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), ) 737 if (N0.getOpcode() == ISD::SHL && N0.Val->hasOneUse()) { 738 SDOperand Result = combineShlAddConstant(N0, N1, DAG); 739 if (Result.Val) return Result; 740 } 741 if (N1.getOpcode() == ISD::SHL && N1.Val->hasOneUse()) { 742 SDOperand Result = combineShlAddConstant(N1, N0, DAG); 743 if (Result.Val) return Result; 744 } 745 746 return SDOperand(); 747} 748 749SDOperand DAGCombiner::visitADDC(SDNode *N) { 750 SDOperand N0 = N->getOperand(0); 751 SDOperand N1 = N->getOperand(1); 752 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 753 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 754 MVT::ValueType VT = N0.getValueType(); 755 756 // If the flag result is dead, turn this into an ADD. 757 if (N->hasNUsesOfValue(0, 1)) 758 return CombineTo(N, DAG.getNode(ISD::ADD, VT, N1, N0), 759 DAG.getNode(ISD::CARRY_FALSE, MVT::Flag)); 760 761 // canonicalize constant to RHS. 762 if (N0C && !N1C) { 763 SDOperand Ops[] = { N1, N0 }; 764 return DAG.getNode(ISD::ADDC, N->getVTList(), Ops, 2); 765 } 766 767 // fold (addc x, 0) -> x + no carry out 768 if (N1C && N1C->isNullValue()) 769 return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE, MVT::Flag)); 770 771 // fold (addc a, b) -> (or a, b), CARRY_FALSE iff a and b share no bits. 772 uint64_t LHSZero, LHSOne; 773 uint64_t RHSZero, RHSOne; 774 uint64_t Mask = MVT::getIntVTBitMask(VT); 775 TLI.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 776 if (LHSZero) { 777 TLI.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 778 779 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 780 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 781 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 782 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 783 return CombineTo(N, DAG.getNode(ISD::OR, VT, N0, N1), 784 DAG.getNode(ISD::CARRY_FALSE, MVT::Flag)); 785 } 786 787 return SDOperand(); 788} 789 790SDOperand DAGCombiner::visitADDE(SDNode *N) { 791 SDOperand N0 = N->getOperand(0); 792 SDOperand N1 = N->getOperand(1); 793 SDOperand CarryIn = N->getOperand(2); 794 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 795 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 796 //MVT::ValueType VT = N0.getValueType(); 797 798 // canonicalize constant to RHS 799 if (N0C && !N1C) { 800 SDOperand Ops[] = { N1, N0, CarryIn }; 801 return DAG.getNode(ISD::ADDE, N->getVTList(), Ops, 3); 802 } 803 804 // fold (adde x, y, false) -> (addc x, y) 805 if (CarryIn.getOpcode() == ISD::CARRY_FALSE) { 806 SDOperand Ops[] = { N1, N0 }; 807 return DAG.getNode(ISD::ADDC, N->getVTList(), Ops, 2); 808 } 809 810 return SDOperand(); 811} 812 813 814 815SDOperand DAGCombiner::visitSUB(SDNode *N) { 816 SDOperand N0 = N->getOperand(0); 817 SDOperand N1 = N->getOperand(1); 818 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val); 819 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 820 MVT::ValueType VT = N0.getValueType(); 821 822 // fold (sub x, x) -> 0 823 if (N0 == N1) 824 return DAG.getConstant(0, N->getValueType(0)); 825 // fold (sub c1, c2) -> c1-c2 826 if (N0C && N1C) 827 return DAG.getNode(ISD::SUB, VT, N0, N1); 828 // fold (sub x, c) -> (add x, -c) 829 if (N1C) 830 return DAG.getNode(ISD::ADD, VT, N0, DAG.getConstant(-N1C->getValue(), VT)); 831 // fold (A+B)-A -> B 832 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1) 833 return N0.getOperand(1); 834 // fold (A+B)-B -> A 835 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) 836 return N0.getOperand(0); 837 return SDOperand(); 838} 839 840SDOperand DAGCombiner::visitMUL(SDNode *N) { 841 SDOperand N0 = N->getOperand(0); 842 SDOperand N1 = N->getOperand(1); 843 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 844 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 845 MVT::ValueType VT = N0.getValueType(); 846 847 // fold (mul c1, c2) -> c1*c2 848 if (N0C && N1C) 849 return DAG.getNode(ISD::MUL, VT, N0, N1); 850 // canonicalize constant to RHS 851 if (N0C && !N1C) 852 return DAG.getNode(ISD::MUL, VT, N1, N0); 853 // fold (mul x, 0) -> 0 854 if (N1C && N1C->isNullValue()) 855 return N1; 856 // fold (mul x, -1) -> 0-x 857 if (N1C && N1C->isAllOnesValue()) 858 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0); 859 // fold (mul x, (1 << c)) -> x << c 860 if (N1C && isPowerOf2_64(N1C->getValue())) 861 return DAG.getNode(ISD::SHL, VT, N0, 862 DAG.getConstant(Log2_64(N1C->getValue()), 863 TLI.getShiftAmountTy())); 864 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c 865 if (N1C && isPowerOf2_64(-N1C->getSignExtended())) { 866 // FIXME: If the input is something that is easily negated (e.g. a 867 // single-use add), we should put the negate there. 868 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), 869 DAG.getNode(ISD::SHL, VT, N0, 870 DAG.getConstant(Log2_64(-N1C->getSignExtended()), 871 TLI.getShiftAmountTy()))); 872 } 873 874 // (mul (shl X, c1), c2) -> (mul X, c2 << c1) 875 if (N1C && N0.getOpcode() == ISD::SHL && 876 isa<ConstantSDNode>(N0.getOperand(1))) { 877 SDOperand C3 = DAG.getNode(ISD::SHL, VT, N1, N0.getOperand(1)); 878 AddToWorkList(C3.Val); 879 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0), C3); 880 } 881 882 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one 883 // use. 884 { 885 SDOperand Sh(0,0), Y(0,0); 886 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)). 887 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) && 888 N0.Val->hasOneUse()) { 889 Sh = N0; Y = N1; 890 } else if (N1.getOpcode() == ISD::SHL && 891 isa<ConstantSDNode>(N1.getOperand(1)) && N1.Val->hasOneUse()) { 892 Sh = N1; Y = N0; 893 } 894 if (Sh.Val) { 895 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Sh.getOperand(0), Y); 896 return DAG.getNode(ISD::SHL, VT, Mul, Sh.getOperand(1)); 897 } 898 } 899 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2) 900 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() && 901 isa<ConstantSDNode>(N0.getOperand(1))) { 902 return DAG.getNode(ISD::ADD, VT, 903 DAG.getNode(ISD::MUL, VT, N0.getOperand(0), N1), 904 DAG.getNode(ISD::MUL, VT, N0.getOperand(1), N1)); 905 } 906 907 // reassociate mul 908 SDOperand RMUL = ReassociateOps(ISD::MUL, N0, N1); 909 if (RMUL.Val != 0) 910 return RMUL; 911 return SDOperand(); 912} 913 914SDOperand DAGCombiner::visitSDIV(SDNode *N) { 915 SDOperand N0 = N->getOperand(0); 916 SDOperand N1 = N->getOperand(1); 917 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val); 918 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 919 MVT::ValueType VT = N->getValueType(0); 920 921 // fold (sdiv c1, c2) -> c1/c2 922 if (N0C && N1C && !N1C->isNullValue()) 923 return DAG.getNode(ISD::SDIV, VT, N0, N1); 924 // fold (sdiv X, 1) -> X 925 if (N1C && N1C->getSignExtended() == 1LL) 926 return N0; 927 // fold (sdiv X, -1) -> 0-X 928 if (N1C && N1C->isAllOnesValue()) 929 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0); 930 // If we know the sign bits of both operands are zero, strength reduce to a 931 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2 932 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1); 933 if (TLI.MaskedValueIsZero(N1, SignBit) && 934 TLI.MaskedValueIsZero(N0, SignBit)) 935 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1); 936 // fold (sdiv X, pow2) -> simple ops after legalize 937 if (N1C && N1C->getValue() && !TLI.isIntDivCheap() && 938 (isPowerOf2_64(N1C->getSignExtended()) || 939 isPowerOf2_64(-N1C->getSignExtended()))) { 940 // If dividing by powers of two is cheap, then don't perform the following 941 // fold. 942 if (TLI.isPow2DivCheap()) 943 return SDOperand(); 944 int64_t pow2 = N1C->getSignExtended(); 945 int64_t abs2 = pow2 > 0 ? pow2 : -pow2; 946 unsigned lg2 = Log2_64(abs2); 947 // Splat the sign bit into the register 948 SDOperand SGN = DAG.getNode(ISD::SRA, VT, N0, 949 DAG.getConstant(MVT::getSizeInBits(VT)-1, 950 TLI.getShiftAmountTy())); 951 AddToWorkList(SGN.Val); 952 // Add (N0 < 0) ? abs2 - 1 : 0; 953 SDOperand SRL = DAG.getNode(ISD::SRL, VT, SGN, 954 DAG.getConstant(MVT::getSizeInBits(VT)-lg2, 955 TLI.getShiftAmountTy())); 956 SDOperand ADD = DAG.getNode(ISD::ADD, VT, N0, SRL); 957 AddToWorkList(SRL.Val); 958 AddToWorkList(ADD.Val); // Divide by pow2 959 SDOperand SRA = DAG.getNode(ISD::SRA, VT, ADD, 960 DAG.getConstant(lg2, TLI.getShiftAmountTy())); 961 // If we're dividing by a positive value, we're done. Otherwise, we must 962 // negate the result. 963 if (pow2 > 0) 964 return SRA; 965 AddToWorkList(SRA.Val); 966 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), SRA); 967 } 968 // if integer divide is expensive and we satisfy the requirements, emit an 969 // alternate sequence. 970 if (N1C && (N1C->getSignExtended() < -1 || N1C->getSignExtended() > 1) && 971 !TLI.isIntDivCheap()) { 972 SDOperand Op = BuildSDIV(N); 973 if (Op.Val) return Op; 974 } 975 return SDOperand(); 976} 977 978SDOperand DAGCombiner::visitUDIV(SDNode *N) { 979 SDOperand N0 = N->getOperand(0); 980 SDOperand N1 = N->getOperand(1); 981 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val); 982 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 983 MVT::ValueType VT = N->getValueType(0); 984 985 // fold (udiv c1, c2) -> c1/c2 986 if (N0C && N1C && !N1C->isNullValue()) 987 return DAG.getNode(ISD::UDIV, VT, N0, N1); 988 // fold (udiv x, (1 << c)) -> x >>u c 989 if (N1C && isPowerOf2_64(N1C->getValue())) 990 return DAG.getNode(ISD::SRL, VT, N0, 991 DAG.getConstant(Log2_64(N1C->getValue()), 992 TLI.getShiftAmountTy())); 993 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2 994 if (N1.getOpcode() == ISD::SHL) { 995 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 996 if (isPowerOf2_64(SHC->getValue())) { 997 MVT::ValueType ADDVT = N1.getOperand(1).getValueType(); 998 SDOperand Add = DAG.getNode(ISD::ADD, ADDVT, N1.getOperand(1), 999 DAG.getConstant(Log2_64(SHC->getValue()), 1000 ADDVT)); 1001 AddToWorkList(Add.Val); 1002 return DAG.getNode(ISD::SRL, VT, N0, Add); 1003 } 1004 } 1005 } 1006 // fold (udiv x, c) -> alternate 1007 if (N1C && N1C->getValue() && !TLI.isIntDivCheap()) { 1008 SDOperand Op = BuildUDIV(N); 1009 if (Op.Val) return Op; 1010 } 1011 return SDOperand(); 1012} 1013 1014SDOperand DAGCombiner::visitSREM(SDNode *N) { 1015 SDOperand N0 = N->getOperand(0); 1016 SDOperand N1 = N->getOperand(1); 1017 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1018 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1019 MVT::ValueType VT = N->getValueType(0); 1020 1021 // fold (srem c1, c2) -> c1%c2 1022 if (N0C && N1C && !N1C->isNullValue()) 1023 return DAG.getNode(ISD::SREM, VT, N0, N1); 1024 // If we know the sign bits of both operands are zero, strength reduce to a 1025 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15 1026 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1); 1027 if (TLI.MaskedValueIsZero(N1, SignBit) && 1028 TLI.MaskedValueIsZero(N0, SignBit)) 1029 return DAG.getNode(ISD::UREM, VT, N0, N1); 1030 1031 // Unconditionally lower X%C -> X-X/C*C. This allows the X/C logic to hack on 1032 // the remainder operation. 1033 if (N1C && !N1C->isNullValue()) { 1034 SDOperand Div = DAG.getNode(ISD::SDIV, VT, N0, N1); 1035 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Div, N1); 1036 SDOperand Sub = DAG.getNode(ISD::SUB, VT, N0, Mul); 1037 AddToWorkList(Div.Val); 1038 AddToWorkList(Mul.Val); 1039 return Sub; 1040 } 1041 1042 return SDOperand(); 1043} 1044 1045SDOperand DAGCombiner::visitUREM(SDNode *N) { 1046 SDOperand N0 = N->getOperand(0); 1047 SDOperand N1 = N->getOperand(1); 1048 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1049 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1050 MVT::ValueType VT = N->getValueType(0); 1051 1052 // fold (urem c1, c2) -> c1%c2 1053 if (N0C && N1C && !N1C->isNullValue()) 1054 return DAG.getNode(ISD::UREM, VT, N0, N1); 1055 // fold (urem x, pow2) -> (and x, pow2-1) 1056 if (N1C && !N1C->isNullValue() && isPowerOf2_64(N1C->getValue())) 1057 return DAG.getNode(ISD::AND, VT, N0, DAG.getConstant(N1C->getValue()-1,VT)); 1058 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1)) 1059 if (N1.getOpcode() == ISD::SHL) { 1060 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 1061 if (isPowerOf2_64(SHC->getValue())) { 1062 SDOperand Add = DAG.getNode(ISD::ADD, VT, N1,DAG.getConstant(~0ULL,VT)); 1063 AddToWorkList(Add.Val); 1064 return DAG.getNode(ISD::AND, VT, N0, Add); 1065 } 1066 } 1067 } 1068 1069 // Unconditionally lower X%C -> X-X/C*C. This allows the X/C logic to hack on 1070 // the remainder operation. 1071 if (N1C && !N1C->isNullValue()) { 1072 SDOperand Div = DAG.getNode(ISD::UDIV, VT, N0, N1); 1073 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Div, N1); 1074 SDOperand Sub = DAG.getNode(ISD::SUB, VT, N0, Mul); 1075 AddToWorkList(Div.Val); 1076 AddToWorkList(Mul.Val); 1077 return Sub; 1078 } 1079 1080 return SDOperand(); 1081} 1082 1083SDOperand DAGCombiner::visitMULHS(SDNode *N) { 1084 SDOperand N0 = N->getOperand(0); 1085 SDOperand N1 = N->getOperand(1); 1086 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1087 1088 // fold (mulhs x, 0) -> 0 1089 if (N1C && N1C->isNullValue()) 1090 return N1; 1091 // fold (mulhs x, 1) -> (sra x, size(x)-1) 1092 if (N1C && N1C->getValue() == 1) 1093 return DAG.getNode(ISD::SRA, N0.getValueType(), N0, 1094 DAG.getConstant(MVT::getSizeInBits(N0.getValueType())-1, 1095 TLI.getShiftAmountTy())); 1096 return SDOperand(); 1097} 1098 1099SDOperand DAGCombiner::visitMULHU(SDNode *N) { 1100 SDOperand N0 = N->getOperand(0); 1101 SDOperand N1 = N->getOperand(1); 1102 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1103 1104 // fold (mulhu x, 0) -> 0 1105 if (N1C && N1C->isNullValue()) 1106 return N1; 1107 // fold (mulhu x, 1) -> 0 1108 if (N1C && N1C->getValue() == 1) 1109 return DAG.getConstant(0, N0.getValueType()); 1110 return SDOperand(); 1111} 1112 1113/// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with 1114/// two operands of the same opcode, try to simplify it. 1115SDOperand DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) { 1116 SDOperand N0 = N->getOperand(0), N1 = N->getOperand(1); 1117 MVT::ValueType VT = N0.getValueType(); 1118 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!"); 1119 1120 // For each of OP in AND/OR/XOR: 1121 // fold (OP (zext x), (zext y)) -> (zext (OP x, y)) 1122 // fold (OP (sext x), (sext y)) -> (sext (OP x, y)) 1123 // fold (OP (aext x), (aext y)) -> (aext (OP x, y)) 1124 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y)) 1125 if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND|| 1126 N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::TRUNCATE) && 1127 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) { 1128 SDOperand ORNode = DAG.getNode(N->getOpcode(), 1129 N0.getOperand(0).getValueType(), 1130 N0.getOperand(0), N1.getOperand(0)); 1131 AddToWorkList(ORNode.Val); 1132 return DAG.getNode(N0.getOpcode(), VT, ORNode); 1133 } 1134 1135 // For each of OP in SHL/SRL/SRA/AND... 1136 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z) 1137 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z) 1138 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z) 1139 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL || 1140 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) && 1141 N0.getOperand(1) == N1.getOperand(1)) { 1142 SDOperand ORNode = DAG.getNode(N->getOpcode(), 1143 N0.getOperand(0).getValueType(), 1144 N0.getOperand(0), N1.getOperand(0)); 1145 AddToWorkList(ORNode.Val); 1146 return DAG.getNode(N0.getOpcode(), VT, ORNode, N0.getOperand(1)); 1147 } 1148 1149 return SDOperand(); 1150} 1151 1152SDOperand DAGCombiner::visitAND(SDNode *N) { 1153 SDOperand N0 = N->getOperand(0); 1154 SDOperand N1 = N->getOperand(1); 1155 SDOperand LL, LR, RL, RR, CC0, CC1; 1156 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1157 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1158 MVT::ValueType VT = N1.getValueType(); 1159 1160 // fold (and c1, c2) -> c1&c2 1161 if (N0C && N1C) 1162 return DAG.getNode(ISD::AND, VT, N0, N1); 1163 // canonicalize constant to RHS 1164 if (N0C && !N1C) 1165 return DAG.getNode(ISD::AND, VT, N1, N0); 1166 // fold (and x, -1) -> x 1167 if (N1C && N1C->isAllOnesValue()) 1168 return N0; 1169 // if (and x, c) is known to be zero, return 0 1170 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT))) 1171 return DAG.getConstant(0, VT); 1172 // reassociate and 1173 SDOperand RAND = ReassociateOps(ISD::AND, N0, N1); 1174 if (RAND.Val != 0) 1175 return RAND; 1176 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF 1177 if (N1C && N0.getOpcode() == ISD::OR) 1178 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 1179 if ((ORI->getValue() & N1C->getValue()) == N1C->getValue()) 1180 return N1; 1181 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits. 1182 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 1183 unsigned InMask = MVT::getIntVTBitMask(N0.getOperand(0).getValueType()); 1184 if (TLI.MaskedValueIsZero(N0.getOperand(0), 1185 ~N1C->getValue() & InMask)) { 1186 SDOperand Zext = DAG.getNode(ISD::ZERO_EXTEND, N0.getValueType(), 1187 N0.getOperand(0)); 1188 1189 // Replace uses of the AND with uses of the Zero extend node. 1190 CombineTo(N, Zext); 1191 1192 // We actually want to replace all uses of the any_extend with the 1193 // zero_extend, to avoid duplicating things. This will later cause this 1194 // AND to be folded. 1195 CombineTo(N0.Val, Zext); 1196 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1197 } 1198 } 1199 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y)) 1200 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 1201 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 1202 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 1203 1204 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 1205 MVT::isInteger(LL.getValueType())) { 1206 // fold (X == 0) & (Y == 0) -> (X|Y == 0) 1207 if (cast<ConstantSDNode>(LR)->getValue() == 0 && Op1 == ISD::SETEQ) { 1208 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1209 AddToWorkList(ORNode.Val); 1210 return DAG.getSetCC(VT, ORNode, LR, Op1); 1211 } 1212 // fold (X == -1) & (Y == -1) -> (X&Y == -1) 1213 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) { 1214 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL); 1215 AddToWorkList(ANDNode.Val); 1216 return DAG.getSetCC(VT, ANDNode, LR, Op1); 1217 } 1218 // fold (X > -1) & (Y > -1) -> (X|Y > -1) 1219 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) { 1220 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1221 AddToWorkList(ORNode.Val); 1222 return DAG.getSetCC(VT, ORNode, LR, Op1); 1223 } 1224 } 1225 // canonicalize equivalent to ll == rl 1226 if (LL == RR && LR == RL) { 1227 Op1 = ISD::getSetCCSwappedOperands(Op1); 1228 std::swap(RL, RR); 1229 } 1230 if (LL == RL && LR == RR) { 1231 bool isInteger = MVT::isInteger(LL.getValueType()); 1232 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger); 1233 if (Result != ISD::SETCC_INVALID) 1234 return DAG.getSetCC(N0.getValueType(), LL, LR, Result); 1235 } 1236 } 1237 1238 // Simplify: and (op x...), (op y...) -> (op (and x, y)) 1239 if (N0.getOpcode() == N1.getOpcode()) { 1240 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1241 if (Tmp.Val) return Tmp; 1242 } 1243 1244 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1) 1245 // fold (and (sra)) -> (and (srl)) when possible. 1246 if (!MVT::isVector(VT) && 1247 SimplifyDemandedBits(SDOperand(N, 0))) 1248 return SDOperand(N, 0); 1249 // fold (zext_inreg (extload x)) -> (zextload x) 1250 if (ISD::isEXTLoad(N0.Val) && ISD::isUNINDEXEDLoad(N0.Val)) { 1251 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1252 MVT::ValueType EVT = LN0->getLoadedVT(); 1253 // If we zero all the possible extended bits, then we can turn this into 1254 // a zextload if we are running before legalize or the operation is legal. 1255 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) && 1256 (!AfterLegalize || TLI.isLoadXLegal(ISD::ZEXTLOAD, EVT))) { 1257 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), 1258 LN0->getBasePtr(), LN0->getSrcValue(), 1259 LN0->getSrcValueOffset(), EVT); 1260 AddToWorkList(N); 1261 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1)); 1262 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1263 } 1264 } 1265 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use 1266 if (ISD::isSEXTLoad(N0.Val) && ISD::isUNINDEXEDLoad(N0.Val) && 1267 N0.hasOneUse()) { 1268 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1269 MVT::ValueType EVT = LN0->getLoadedVT(); 1270 // If we zero all the possible extended bits, then we can turn this into 1271 // a zextload if we are running before legalize or the operation is legal. 1272 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) && 1273 (!AfterLegalize || TLI.isLoadXLegal(ISD::ZEXTLOAD, EVT))) { 1274 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), 1275 LN0->getBasePtr(), LN0->getSrcValue(), 1276 LN0->getSrcValueOffset(), EVT); 1277 AddToWorkList(N); 1278 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1)); 1279 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1280 } 1281 } 1282 1283 // fold (and (load x), 255) -> (zextload x, i8) 1284 // fold (and (extload x, i16), 255) -> (zextload x, i8) 1285 if (N1C && N0.getOpcode() == ISD::LOAD) { 1286 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 1287 if (LN0->getExtensionType() != ISD::SEXTLOAD && 1288 LN0->getAddressingMode() == ISD::UNINDEXED && 1289 N0.hasOneUse()) { 1290 MVT::ValueType EVT, LoadedVT; 1291 if (N1C->getValue() == 255) 1292 EVT = MVT::i8; 1293 else if (N1C->getValue() == 65535) 1294 EVT = MVT::i16; 1295 else if (N1C->getValue() == ~0U) 1296 EVT = MVT::i32; 1297 else 1298 EVT = MVT::Other; 1299 1300 LoadedVT = LN0->getLoadedVT(); 1301 if (EVT != MVT::Other && LoadedVT > EVT && 1302 (!AfterLegalize || TLI.isLoadXLegal(ISD::ZEXTLOAD, EVT))) { 1303 MVT::ValueType PtrType = N0.getOperand(1).getValueType(); 1304 // For big endian targets, we need to add an offset to the pointer to 1305 // load the correct bytes. For little endian systems, we merely need to 1306 // read fewer bytes from the same pointer. 1307 unsigned PtrOff = 1308 (MVT::getSizeInBits(LoadedVT) - MVT::getSizeInBits(EVT)) / 8; 1309 SDOperand NewPtr = LN0->getBasePtr(); 1310 if (!TLI.isLittleEndian()) 1311 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr, 1312 DAG.getConstant(PtrOff, PtrType)); 1313 AddToWorkList(NewPtr.Val); 1314 SDOperand Load = 1315 DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), NewPtr, 1316 LN0->getSrcValue(), LN0->getSrcValueOffset(), EVT); 1317 AddToWorkList(N); 1318 CombineTo(N0.Val, Load, Load.getValue(1)); 1319 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1320 } 1321 } 1322 } 1323 1324 return SDOperand(); 1325} 1326 1327SDOperand DAGCombiner::visitOR(SDNode *N) { 1328 SDOperand N0 = N->getOperand(0); 1329 SDOperand N1 = N->getOperand(1); 1330 SDOperand LL, LR, RL, RR, CC0, CC1; 1331 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1332 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1333 MVT::ValueType VT = N1.getValueType(); 1334 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 1335 1336 // fold (or c1, c2) -> c1|c2 1337 if (N0C && N1C) 1338 return DAG.getNode(ISD::OR, VT, N0, N1); 1339 // canonicalize constant to RHS 1340 if (N0C && !N1C) 1341 return DAG.getNode(ISD::OR, VT, N1, N0); 1342 // fold (or x, 0) -> x 1343 if (N1C && N1C->isNullValue()) 1344 return N0; 1345 // fold (or x, -1) -> -1 1346 if (N1C && N1C->isAllOnesValue()) 1347 return N1; 1348 // fold (or x, c) -> c iff (x & ~c) == 0 1349 if (N1C && 1350 TLI.MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits)))) 1351 return N1; 1352 // reassociate or 1353 SDOperand ROR = ReassociateOps(ISD::OR, N0, N1); 1354 if (ROR.Val != 0) 1355 return ROR; 1356 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2) 1357 if (N1C && N0.getOpcode() == ISD::AND && N0.Val->hasOneUse() && 1358 isa<ConstantSDNode>(N0.getOperand(1))) { 1359 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1)); 1360 return DAG.getNode(ISD::AND, VT, DAG.getNode(ISD::OR, VT, N0.getOperand(0), 1361 N1), 1362 DAG.getConstant(N1C->getValue() | C1->getValue(), VT)); 1363 } 1364 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y)) 1365 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 1366 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 1367 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 1368 1369 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 1370 MVT::isInteger(LL.getValueType())) { 1371 // fold (X != 0) | (Y != 0) -> (X|Y != 0) 1372 // fold (X < 0) | (Y < 0) -> (X|Y < 0) 1373 if (cast<ConstantSDNode>(LR)->getValue() == 0 && 1374 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) { 1375 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1376 AddToWorkList(ORNode.Val); 1377 return DAG.getSetCC(VT, ORNode, LR, Op1); 1378 } 1379 // fold (X != -1) | (Y != -1) -> (X&Y != -1) 1380 // fold (X > -1) | (Y > -1) -> (X&Y > -1) 1381 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && 1382 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) { 1383 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL); 1384 AddToWorkList(ANDNode.Val); 1385 return DAG.getSetCC(VT, ANDNode, LR, Op1); 1386 } 1387 } 1388 // canonicalize equivalent to ll == rl 1389 if (LL == RR && LR == RL) { 1390 Op1 = ISD::getSetCCSwappedOperands(Op1); 1391 std::swap(RL, RR); 1392 } 1393 if (LL == RL && LR == RR) { 1394 bool isInteger = MVT::isInteger(LL.getValueType()); 1395 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger); 1396 if (Result != ISD::SETCC_INVALID) 1397 return DAG.getSetCC(N0.getValueType(), LL, LR, Result); 1398 } 1399 } 1400 1401 // Simplify: or (op x...), (op y...) -> (op (or x, y)) 1402 if (N0.getOpcode() == N1.getOpcode()) { 1403 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1404 if (Tmp.Val) return Tmp; 1405 } 1406 1407 // (X & C1) | (Y & C2) -> (X|Y) & C3 if possible. 1408 if (N0.getOpcode() == ISD::AND && 1409 N1.getOpcode() == ISD::AND && 1410 N0.getOperand(1).getOpcode() == ISD::Constant && 1411 N1.getOperand(1).getOpcode() == ISD::Constant && 1412 // Don't increase # computations. 1413 (N0.Val->hasOneUse() || N1.Val->hasOneUse())) { 1414 // We can only do this xform if we know that bits from X that are set in C2 1415 // but not in C1 are already zero. Likewise for Y. 1416 uint64_t LHSMask = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1417 uint64_t RHSMask = cast<ConstantSDNode>(N1.getOperand(1))->getValue(); 1418 1419 if (TLI.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) && 1420 TLI.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) { 1421 SDOperand X =DAG.getNode(ISD::OR, VT, N0.getOperand(0), N1.getOperand(0)); 1422 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(LHSMask|RHSMask, VT)); 1423 } 1424 } 1425 1426 1427 // See if this is some rotate idiom. 1428 if (SDNode *Rot = MatchRotate(N0, N1)) 1429 return SDOperand(Rot, 0); 1430 1431 return SDOperand(); 1432} 1433 1434 1435/// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present. 1436static bool MatchRotateHalf(SDOperand Op, SDOperand &Shift, SDOperand &Mask) { 1437 if (Op.getOpcode() == ISD::AND) { 1438 if (isa<ConstantSDNode>(Op.getOperand(1))) { 1439 Mask = Op.getOperand(1); 1440 Op = Op.getOperand(0); 1441 } else { 1442 return false; 1443 } 1444 } 1445 1446 if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) { 1447 Shift = Op; 1448 return true; 1449 } 1450 return false; 1451} 1452 1453 1454// MatchRotate - Handle an 'or' of two operands. If this is one of the many 1455// idioms for rotate, and if the target supports rotation instructions, generate 1456// a rot[lr]. 1457SDNode *DAGCombiner::MatchRotate(SDOperand LHS, SDOperand RHS) { 1458 // Must be a legal type. Expanded an promoted things won't work with rotates. 1459 MVT::ValueType VT = LHS.getValueType(); 1460 if (!TLI.isTypeLegal(VT)) return 0; 1461 1462 // The target must have at least one rotate flavor. 1463 bool HasROTL = TLI.isOperationLegal(ISD::ROTL, VT); 1464 bool HasROTR = TLI.isOperationLegal(ISD::ROTR, VT); 1465 if (!HasROTL && !HasROTR) return 0; 1466 1467 // Match "(X shl/srl V1) & V2" where V2 may not be present. 1468 SDOperand LHSShift; // The shift. 1469 SDOperand LHSMask; // AND value if any. 1470 if (!MatchRotateHalf(LHS, LHSShift, LHSMask)) 1471 return 0; // Not part of a rotate. 1472 1473 SDOperand RHSShift; // The shift. 1474 SDOperand RHSMask; // AND value if any. 1475 if (!MatchRotateHalf(RHS, RHSShift, RHSMask)) 1476 return 0; // Not part of a rotate. 1477 1478 if (LHSShift.getOperand(0) != RHSShift.getOperand(0)) 1479 return 0; // Not shifting the same value. 1480 1481 if (LHSShift.getOpcode() == RHSShift.getOpcode()) 1482 return 0; // Shifts must disagree. 1483 1484 // Canonicalize shl to left side in a shl/srl pair. 1485 if (RHSShift.getOpcode() == ISD::SHL) { 1486 std::swap(LHS, RHS); 1487 std::swap(LHSShift, RHSShift); 1488 std::swap(LHSMask , RHSMask ); 1489 } 1490 1491 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 1492 SDOperand LHSShiftArg = LHSShift.getOperand(0); 1493 SDOperand LHSShiftAmt = LHSShift.getOperand(1); 1494 SDOperand RHSShiftAmt = RHSShift.getOperand(1); 1495 1496 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1) 1497 // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2) 1498 if (LHSShiftAmt.getOpcode() == ISD::Constant && 1499 RHSShiftAmt.getOpcode() == ISD::Constant) { 1500 uint64_t LShVal = cast<ConstantSDNode>(LHSShiftAmt)->getValue(); 1501 uint64_t RShVal = cast<ConstantSDNode>(RHSShiftAmt)->getValue(); 1502 if ((LShVal + RShVal) != OpSizeInBits) 1503 return 0; 1504 1505 SDOperand Rot; 1506 if (HasROTL) 1507 Rot = DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt); 1508 else 1509 Rot = DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt); 1510 1511 // If there is an AND of either shifted operand, apply it to the result. 1512 if (LHSMask.Val || RHSMask.Val) { 1513 uint64_t Mask = MVT::getIntVTBitMask(VT); 1514 1515 if (LHSMask.Val) { 1516 uint64_t RHSBits = (1ULL << LShVal)-1; 1517 Mask &= cast<ConstantSDNode>(LHSMask)->getValue() | RHSBits; 1518 } 1519 if (RHSMask.Val) { 1520 uint64_t LHSBits = ~((1ULL << (OpSizeInBits-RShVal))-1); 1521 Mask &= cast<ConstantSDNode>(RHSMask)->getValue() | LHSBits; 1522 } 1523 1524 Rot = DAG.getNode(ISD::AND, VT, Rot, DAG.getConstant(Mask, VT)); 1525 } 1526 1527 return Rot.Val; 1528 } 1529 1530 // If there is a mask here, and we have a variable shift, we can't be sure 1531 // that we're masking out the right stuff. 1532 if (LHSMask.Val || RHSMask.Val) 1533 return 0; 1534 1535 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y) 1536 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y)) 1537 if (RHSShiftAmt.getOpcode() == ISD::SUB && 1538 LHSShiftAmt == RHSShiftAmt.getOperand(1)) { 1539 if (ConstantSDNode *SUBC = 1540 dyn_cast<ConstantSDNode>(RHSShiftAmt.getOperand(0))) { 1541 if (SUBC->getValue() == OpSizeInBits) 1542 if (HasROTL) 1543 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt).Val; 1544 else 1545 return DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt).Val; 1546 } 1547 } 1548 1549 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y) 1550 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y)) 1551 if (LHSShiftAmt.getOpcode() == ISD::SUB && 1552 RHSShiftAmt == LHSShiftAmt.getOperand(1)) { 1553 if (ConstantSDNode *SUBC = 1554 dyn_cast<ConstantSDNode>(LHSShiftAmt.getOperand(0))) { 1555 if (SUBC->getValue() == OpSizeInBits) 1556 if (HasROTL) 1557 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt).Val; 1558 else 1559 return DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt).Val; 1560 } 1561 } 1562 1563 // Look for sign/zext/any-extended cases: 1564 if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND 1565 || LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND 1566 || LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND) && 1567 (RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND 1568 || RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND 1569 || RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND)) { 1570 SDOperand LExtOp0 = LHSShiftAmt.getOperand(0); 1571 SDOperand RExtOp0 = RHSShiftAmt.getOperand(0); 1572 if (RExtOp0.getOpcode() == ISD::SUB && 1573 RExtOp0.getOperand(1) == LExtOp0) { 1574 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> 1575 // (rotr x, y) 1576 // fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) -> 1577 // (rotl x, (sub 32, y)) 1578 if (ConstantSDNode *SUBC = cast<ConstantSDNode>(RExtOp0.getOperand(0))) { 1579 if (SUBC->getValue() == OpSizeInBits) { 1580 if (HasROTL) 1581 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt).Val; 1582 else 1583 return DAG.getNode(ISD::ROTR, VT, LHSShiftArg, RHSShiftAmt).Val; 1584 } 1585 } 1586 } else if (LExtOp0.getOpcode() == ISD::SUB && 1587 RExtOp0 == LExtOp0.getOperand(1)) { 1588 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext r))) -> 1589 // (rotl x, y) 1590 // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext r))) -> 1591 // (rotr x, (sub 32, y)) 1592 if (ConstantSDNode *SUBC = cast<ConstantSDNode>(LExtOp0.getOperand(0))) { 1593 if (SUBC->getValue() == OpSizeInBits) { 1594 if (HasROTL) 1595 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, RHSShiftAmt).Val; 1596 else 1597 return DAG.getNode(ISD::ROTL, VT, LHSShiftArg, LHSShiftAmt).Val; 1598 } 1599 } 1600 } 1601 } 1602 1603 return 0; 1604} 1605 1606 1607SDOperand DAGCombiner::visitXOR(SDNode *N) { 1608 SDOperand N0 = N->getOperand(0); 1609 SDOperand N1 = N->getOperand(1); 1610 SDOperand LHS, RHS, CC; 1611 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1612 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1613 MVT::ValueType VT = N0.getValueType(); 1614 1615 // fold (xor c1, c2) -> c1^c2 1616 if (N0C && N1C) 1617 return DAG.getNode(ISD::XOR, VT, N0, N1); 1618 // canonicalize constant to RHS 1619 if (N0C && !N1C) 1620 return DAG.getNode(ISD::XOR, VT, N1, N0); 1621 // fold (xor x, 0) -> x 1622 if (N1C && N1C->isNullValue()) 1623 return N0; 1624 // reassociate xor 1625 SDOperand RXOR = ReassociateOps(ISD::XOR, N0, N1); 1626 if (RXOR.Val != 0) 1627 return RXOR; 1628 // fold !(x cc y) -> (x !cc y) 1629 if (N1C && N1C->getValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) { 1630 bool isInt = MVT::isInteger(LHS.getValueType()); 1631 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(), 1632 isInt); 1633 if (N0.getOpcode() == ISD::SETCC) 1634 return DAG.getSetCC(VT, LHS, RHS, NotCC); 1635 if (N0.getOpcode() == ISD::SELECT_CC) 1636 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),N0.getOperand(3),NotCC); 1637 assert(0 && "Unhandled SetCC Equivalent!"); 1638 abort(); 1639 } 1640 // fold !(x or y) -> (!x and !y) iff x or y are setcc 1641 if (N1C && N1C->getValue() == 1 && VT == MVT::i1 && 1642 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 1643 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1); 1644 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) { 1645 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 1646 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS 1647 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS 1648 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val); 1649 return DAG.getNode(NewOpcode, VT, LHS, RHS); 1650 } 1651 } 1652 // fold !(x or y) -> (!x and !y) iff x or y are constants 1653 if (N1C && N1C->isAllOnesValue() && 1654 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 1655 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1); 1656 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) { 1657 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 1658 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS 1659 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS 1660 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val); 1661 return DAG.getNode(NewOpcode, VT, LHS, RHS); 1662 } 1663 } 1664 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2) 1665 if (N1C && N0.getOpcode() == ISD::XOR) { 1666 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0)); 1667 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 1668 if (N00C) 1669 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1), 1670 DAG.getConstant(N1C->getValue()^N00C->getValue(), VT)); 1671 if (N01C) 1672 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0), 1673 DAG.getConstant(N1C->getValue()^N01C->getValue(), VT)); 1674 } 1675 // fold (xor x, x) -> 0 1676 if (N0 == N1) { 1677 if (!MVT::isVector(VT)) { 1678 return DAG.getConstant(0, VT); 1679 } else if (!AfterLegalize || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) { 1680 // Produce a vector of zeros. 1681 SDOperand El = DAG.getConstant(0, MVT::getVectorBaseType(VT)); 1682 std::vector<SDOperand> Ops(MVT::getVectorNumElements(VT), El); 1683 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size()); 1684 } 1685 } 1686 1687 // Simplify: xor (op x...), (op y...) -> (op (xor x, y)) 1688 if (N0.getOpcode() == N1.getOpcode()) { 1689 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1690 if (Tmp.Val) return Tmp; 1691 } 1692 1693 // Simplify the expression using non-local knowledge. 1694 if (!MVT::isVector(VT) && 1695 SimplifyDemandedBits(SDOperand(N, 0))) 1696 return SDOperand(N, 0); 1697 1698 return SDOperand(); 1699} 1700 1701SDOperand DAGCombiner::visitSHL(SDNode *N) { 1702 SDOperand N0 = N->getOperand(0); 1703 SDOperand N1 = N->getOperand(1); 1704 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1705 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1706 MVT::ValueType VT = N0.getValueType(); 1707 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 1708 1709 // fold (shl c1, c2) -> c1<<c2 1710 if (N0C && N1C) 1711 return DAG.getNode(ISD::SHL, VT, N0, N1); 1712 // fold (shl 0, x) -> 0 1713 if (N0C && N0C->isNullValue()) 1714 return N0; 1715 // fold (shl x, c >= size(x)) -> undef 1716 if (N1C && N1C->getValue() >= OpSizeInBits) 1717 return DAG.getNode(ISD::UNDEF, VT); 1718 // fold (shl x, 0) -> x 1719 if (N1C && N1C->isNullValue()) 1720 return N0; 1721 // if (shl x, c) is known to be zero, return 0 1722 if (TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT))) 1723 return DAG.getConstant(0, VT); 1724 if (SimplifyDemandedBits(SDOperand(N, 0))) 1725 return SDOperand(N, 0); 1726 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2) 1727 if (N1C && N0.getOpcode() == ISD::SHL && 1728 N0.getOperand(1).getOpcode() == ISD::Constant) { 1729 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1730 uint64_t c2 = N1C->getValue(); 1731 if (c1 + c2 > OpSizeInBits) 1732 return DAG.getConstant(0, VT); 1733 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0), 1734 DAG.getConstant(c1 + c2, N1.getValueType())); 1735 } 1736 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or 1737 // (srl (and x, -1 << c1), c1-c2) 1738 if (N1C && N0.getOpcode() == ISD::SRL && 1739 N0.getOperand(1).getOpcode() == ISD::Constant) { 1740 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1741 uint64_t c2 = N1C->getValue(); 1742 SDOperand Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0), 1743 DAG.getConstant(~0ULL << c1, VT)); 1744 if (c2 > c1) 1745 return DAG.getNode(ISD::SHL, VT, Mask, 1746 DAG.getConstant(c2-c1, N1.getValueType())); 1747 else 1748 return DAG.getNode(ISD::SRL, VT, Mask, 1749 DAG.getConstant(c1-c2, N1.getValueType())); 1750 } 1751 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1) 1752 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) 1753 return DAG.getNode(ISD::AND, VT, N0.getOperand(0), 1754 DAG.getConstant(~0ULL << N1C->getValue(), VT)); 1755 return SDOperand(); 1756} 1757 1758SDOperand DAGCombiner::visitSRA(SDNode *N) { 1759 SDOperand N0 = N->getOperand(0); 1760 SDOperand N1 = N->getOperand(1); 1761 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1762 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1763 MVT::ValueType VT = N0.getValueType(); 1764 1765 // fold (sra c1, c2) -> c1>>c2 1766 if (N0C && N1C) 1767 return DAG.getNode(ISD::SRA, VT, N0, N1); 1768 // fold (sra 0, x) -> 0 1769 if (N0C && N0C->isNullValue()) 1770 return N0; 1771 // fold (sra -1, x) -> -1 1772 if (N0C && N0C->isAllOnesValue()) 1773 return N0; 1774 // fold (sra x, c >= size(x)) -> undef 1775 if (N1C && N1C->getValue() >= MVT::getSizeInBits(VT)) 1776 return DAG.getNode(ISD::UNDEF, VT); 1777 // fold (sra x, 0) -> x 1778 if (N1C && N1C->isNullValue()) 1779 return N0; 1780 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports 1781 // sext_inreg. 1782 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) { 1783 unsigned LowBits = MVT::getSizeInBits(VT) - (unsigned)N1C->getValue(); 1784 MVT::ValueType EVT; 1785 switch (LowBits) { 1786 default: EVT = MVT::Other; break; 1787 case 1: EVT = MVT::i1; break; 1788 case 8: EVT = MVT::i8; break; 1789 case 16: EVT = MVT::i16; break; 1790 case 32: EVT = MVT::i32; break; 1791 } 1792 if (EVT > MVT::Other && TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, EVT)) 1793 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), 1794 DAG.getValueType(EVT)); 1795 } 1796 1797 // fold (sra (sra x, c1), c2) -> (sra x, c1+c2) 1798 if (N1C && N0.getOpcode() == ISD::SRA) { 1799 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 1800 unsigned Sum = N1C->getValue() + C1->getValue(); 1801 if (Sum >= MVT::getSizeInBits(VT)) Sum = MVT::getSizeInBits(VT)-1; 1802 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), 1803 DAG.getConstant(Sum, N1C->getValueType(0))); 1804 } 1805 } 1806 1807 // Simplify, based on bits shifted out of the LHS. 1808 if (N1C && SimplifyDemandedBits(SDOperand(N, 0))) 1809 return SDOperand(N, 0); 1810 1811 1812 // If the sign bit is known to be zero, switch this to a SRL. 1813 if (TLI.MaskedValueIsZero(N0, MVT::getIntVTSignBit(VT))) 1814 return DAG.getNode(ISD::SRL, VT, N0, N1); 1815 return SDOperand(); 1816} 1817 1818SDOperand DAGCombiner::visitSRL(SDNode *N) { 1819 SDOperand N0 = N->getOperand(0); 1820 SDOperand N1 = N->getOperand(1); 1821 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1822 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1823 MVT::ValueType VT = N0.getValueType(); 1824 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 1825 1826 // fold (srl c1, c2) -> c1 >>u c2 1827 if (N0C && N1C) 1828 return DAG.getNode(ISD::SRL, VT, N0, N1); 1829 // fold (srl 0, x) -> 0 1830 if (N0C && N0C->isNullValue()) 1831 return N0; 1832 // fold (srl x, c >= size(x)) -> undef 1833 if (N1C && N1C->getValue() >= OpSizeInBits) 1834 return DAG.getNode(ISD::UNDEF, VT); 1835 // fold (srl x, 0) -> x 1836 if (N1C && N1C->isNullValue()) 1837 return N0; 1838 // if (srl x, c) is known to be zero, return 0 1839 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits))) 1840 return DAG.getConstant(0, VT); 1841 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2) 1842 if (N1C && N0.getOpcode() == ISD::SRL && 1843 N0.getOperand(1).getOpcode() == ISD::Constant) { 1844 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1845 uint64_t c2 = N1C->getValue(); 1846 if (c1 + c2 > OpSizeInBits) 1847 return DAG.getConstant(0, VT); 1848 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0), 1849 DAG.getConstant(c1 + c2, N1.getValueType())); 1850 } 1851 1852 // fold (srl (anyextend x), c) -> (anyextend (srl x, c)) 1853 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 1854 // Shifting in all undef bits? 1855 MVT::ValueType SmallVT = N0.getOperand(0).getValueType(); 1856 if (N1C->getValue() >= MVT::getSizeInBits(SmallVT)) 1857 return DAG.getNode(ISD::UNDEF, VT); 1858 1859 SDOperand SmallShift = DAG.getNode(ISD::SRL, SmallVT, N0.getOperand(0), N1); 1860 AddToWorkList(SmallShift.Val); 1861 return DAG.getNode(ISD::ANY_EXTEND, VT, SmallShift); 1862 } 1863 1864 // fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign 1865 // bit, which is unmodified by sra. 1866 if (N1C && N1C->getValue()+1 == MVT::getSizeInBits(VT)) { 1867 if (N0.getOpcode() == ISD::SRA) 1868 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0), N1); 1869 } 1870 1871 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit). 1872 if (N1C && N0.getOpcode() == ISD::CTLZ && 1873 N1C->getValue() == Log2_32(MVT::getSizeInBits(VT))) { 1874 uint64_t KnownZero, KnownOne, Mask = MVT::getIntVTBitMask(VT); 1875 TLI.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne); 1876 1877 // If any of the input bits are KnownOne, then the input couldn't be all 1878 // zeros, thus the result of the srl will always be zero. 1879 if (KnownOne) return DAG.getConstant(0, VT); 1880 1881 // If all of the bits input the to ctlz node are known to be zero, then 1882 // the result of the ctlz is "32" and the result of the shift is one. 1883 uint64_t UnknownBits = ~KnownZero & Mask; 1884 if (UnknownBits == 0) return DAG.getConstant(1, VT); 1885 1886 // Otherwise, check to see if there is exactly one bit input to the ctlz. 1887 if ((UnknownBits & (UnknownBits-1)) == 0) { 1888 // Okay, we know that only that the single bit specified by UnknownBits 1889 // could be set on input to the CTLZ node. If this bit is set, the SRL 1890 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair 1891 // to an SRL,XOR pair, which is likely to simplify more. 1892 unsigned ShAmt = CountTrailingZeros_64(UnknownBits); 1893 SDOperand Op = N0.getOperand(0); 1894 if (ShAmt) { 1895 Op = DAG.getNode(ISD::SRL, VT, Op, 1896 DAG.getConstant(ShAmt, TLI.getShiftAmountTy())); 1897 AddToWorkList(Op.Val); 1898 } 1899 return DAG.getNode(ISD::XOR, VT, Op, DAG.getConstant(1, VT)); 1900 } 1901 } 1902 1903 return SDOperand(); 1904} 1905 1906SDOperand DAGCombiner::visitCTLZ(SDNode *N) { 1907 SDOperand N0 = N->getOperand(0); 1908 MVT::ValueType VT = N->getValueType(0); 1909 1910 // fold (ctlz c1) -> c2 1911 if (isa<ConstantSDNode>(N0)) 1912 return DAG.getNode(ISD::CTLZ, VT, N0); 1913 return SDOperand(); 1914} 1915 1916SDOperand DAGCombiner::visitCTTZ(SDNode *N) { 1917 SDOperand N0 = N->getOperand(0); 1918 MVT::ValueType VT = N->getValueType(0); 1919 1920 // fold (cttz c1) -> c2 1921 if (isa<ConstantSDNode>(N0)) 1922 return DAG.getNode(ISD::CTTZ, VT, N0); 1923 return SDOperand(); 1924} 1925 1926SDOperand DAGCombiner::visitCTPOP(SDNode *N) { 1927 SDOperand N0 = N->getOperand(0); 1928 MVT::ValueType VT = N->getValueType(0); 1929 1930 // fold (ctpop c1) -> c2 1931 if (isa<ConstantSDNode>(N0)) 1932 return DAG.getNode(ISD::CTPOP, VT, N0); 1933 return SDOperand(); 1934} 1935 1936SDOperand DAGCombiner::visitSELECT(SDNode *N) { 1937 SDOperand N0 = N->getOperand(0); 1938 SDOperand N1 = N->getOperand(1); 1939 SDOperand N2 = N->getOperand(2); 1940 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1941 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1942 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2); 1943 MVT::ValueType VT = N->getValueType(0); 1944 1945 // fold select C, X, X -> X 1946 if (N1 == N2) 1947 return N1; 1948 // fold select true, X, Y -> X 1949 if (N0C && !N0C->isNullValue()) 1950 return N1; 1951 // fold select false, X, Y -> Y 1952 if (N0C && N0C->isNullValue()) 1953 return N2; 1954 // fold select C, 1, X -> C | X 1955 if (MVT::i1 == VT && N1C && N1C->getValue() == 1) 1956 return DAG.getNode(ISD::OR, VT, N0, N2); 1957 // fold select C, 0, X -> ~C & X 1958 // FIXME: this should check for C type == X type, not i1? 1959 if (MVT::i1 == VT && N1C && N1C->isNullValue()) { 1960 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT)); 1961 AddToWorkList(XORNode.Val); 1962 return DAG.getNode(ISD::AND, VT, XORNode, N2); 1963 } 1964 // fold select C, X, 1 -> ~C | X 1965 if (MVT::i1 == VT && N2C && N2C->getValue() == 1) { 1966 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT)); 1967 AddToWorkList(XORNode.Val); 1968 return DAG.getNode(ISD::OR, VT, XORNode, N1); 1969 } 1970 // fold select C, X, 0 -> C & X 1971 // FIXME: this should check for C type == X type, not i1? 1972 if (MVT::i1 == VT && N2C && N2C->isNullValue()) 1973 return DAG.getNode(ISD::AND, VT, N0, N1); 1974 // fold X ? X : Y --> X ? 1 : Y --> X | Y 1975 if (MVT::i1 == VT && N0 == N1) 1976 return DAG.getNode(ISD::OR, VT, N0, N2); 1977 // fold X ? Y : X --> X ? Y : 0 --> X & Y 1978 if (MVT::i1 == VT && N0 == N2) 1979 return DAG.getNode(ISD::AND, VT, N0, N1); 1980 1981 // If we can fold this based on the true/false value, do so. 1982 if (SimplifySelectOps(N, N1, N2)) 1983 return SDOperand(N, 0); // Don't revisit N. 1984 1985 // fold selects based on a setcc into other things, such as min/max/abs 1986 if (N0.getOpcode() == ISD::SETCC) 1987 // FIXME: 1988 // Check against MVT::Other for SELECT_CC, which is a workaround for targets 1989 // having to say they don't support SELECT_CC on every type the DAG knows 1990 // about, since there is no way to mark an opcode illegal at all value types 1991 if (TLI.isOperationLegal(ISD::SELECT_CC, MVT::Other)) 1992 return DAG.getNode(ISD::SELECT_CC, VT, N0.getOperand(0), N0.getOperand(1), 1993 N1, N2, N0.getOperand(2)); 1994 else 1995 return SimplifySelect(N0, N1, N2); 1996 return SDOperand(); 1997} 1998 1999SDOperand DAGCombiner::visitSELECT_CC(SDNode *N) { 2000 SDOperand N0 = N->getOperand(0); 2001 SDOperand N1 = N->getOperand(1); 2002 SDOperand N2 = N->getOperand(2); 2003 SDOperand N3 = N->getOperand(3); 2004 SDOperand N4 = N->getOperand(4); 2005 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get(); 2006 2007 // fold select_cc lhs, rhs, x, x, cc -> x 2008 if (N2 == N3) 2009 return N2; 2010 2011 // Determine if the condition we're dealing with is constant 2012 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false); 2013 if (SCC.Val) AddToWorkList(SCC.Val); 2014 2015 if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val)) { 2016 if (SCCC->getValue()) 2017 return N2; // cond always true -> true val 2018 else 2019 return N3; // cond always false -> false val 2020 } 2021 2022 // Fold to a simpler select_cc 2023 if (SCC.Val && SCC.getOpcode() == ISD::SETCC) 2024 return DAG.getNode(ISD::SELECT_CC, N2.getValueType(), 2025 SCC.getOperand(0), SCC.getOperand(1), N2, N3, 2026 SCC.getOperand(2)); 2027 2028 // If we can fold this based on the true/false value, do so. 2029 if (SimplifySelectOps(N, N2, N3)) 2030 return SDOperand(N, 0); // Don't revisit N. 2031 2032 // fold select_cc into other things, such as min/max/abs 2033 return SimplifySelectCC(N0, N1, N2, N3, CC); 2034} 2035 2036SDOperand DAGCombiner::visitSETCC(SDNode *N) { 2037 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1), 2038 cast<CondCodeSDNode>(N->getOperand(2))->get()); 2039} 2040 2041SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) { 2042 SDOperand N0 = N->getOperand(0); 2043 MVT::ValueType VT = N->getValueType(0); 2044 2045 // fold (sext c1) -> c1 2046 if (isa<ConstantSDNode>(N0)) 2047 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0); 2048 2049 // fold (sext (sext x)) -> (sext x) 2050 // fold (sext (aext x)) -> (sext x) 2051 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 2052 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0)); 2053 2054 // fold (sext (truncate (load x))) -> (sext (smaller load x)) 2055 // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n))) 2056 if (N0.getOpcode() == ISD::TRUNCATE) { 2057 SDOperand NarrowLoad = ReduceLoadWidth(N0.Val); 2058 if (NarrowLoad.Val) { 2059 if (NarrowLoad.Val != N0.Val) 2060 CombineTo(N0.Val, NarrowLoad); 2061 return DAG.getNode(ISD::SIGN_EXTEND, VT, NarrowLoad); 2062 } 2063 } 2064 2065 // See if the value being truncated is already sign extended. If so, just 2066 // eliminate the trunc/sext pair. 2067 if (N0.getOpcode() == ISD::TRUNCATE) { 2068 SDOperand Op = N0.getOperand(0); 2069 unsigned OpBits = MVT::getSizeInBits(Op.getValueType()); 2070 unsigned MidBits = MVT::getSizeInBits(N0.getValueType()); 2071 unsigned DestBits = MVT::getSizeInBits(VT); 2072 unsigned NumSignBits = TLI.ComputeNumSignBits(Op); 2073 2074 if (OpBits == DestBits) { 2075 // Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign 2076 // bits, it is already ready. 2077 if (NumSignBits > DestBits-MidBits) 2078 return Op; 2079 } else if (OpBits < DestBits) { 2080 // Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign 2081 // bits, just sext from i32. 2082 if (NumSignBits > OpBits-MidBits) 2083 return DAG.getNode(ISD::SIGN_EXTEND, VT, Op); 2084 } else { 2085 // Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign 2086 // bits, just truncate to i32. 2087 if (NumSignBits > OpBits-MidBits) 2088 return DAG.getNode(ISD::TRUNCATE, VT, Op); 2089 } 2090 2091 // fold (sext (truncate x)) -> (sextinreg x). 2092 if (!AfterLegalize || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, 2093 N0.getValueType())) { 2094 if (Op.getValueType() < VT) 2095 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op); 2096 else if (Op.getValueType() > VT) 2097 Op = DAG.getNode(ISD::TRUNCATE, VT, Op); 2098 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, Op, 2099 DAG.getValueType(N0.getValueType())); 2100 } 2101 } 2102 2103 // fold (sext (load x)) -> (sext (truncate (sextload x))) 2104 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() && 2105 (!AfterLegalize||TLI.isLoadXLegal(ISD::SEXTLOAD, N0.getValueType()))){ 2106 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2107 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(), 2108 LN0->getBasePtr(), LN0->getSrcValue(), 2109 LN0->getSrcValueOffset(), 2110 N0.getValueType()); 2111 CombineTo(N, ExtLoad); 2112 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 2113 ExtLoad.getValue(1)); 2114 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2115 } 2116 2117 // fold (sext (sextload x)) -> (sext (truncate (sextload x))) 2118 // fold (sext ( extload x)) -> (sext (truncate (sextload x))) 2119 if ((ISD::isSEXTLoad(N0.Val) || ISD::isEXTLoad(N0.Val)) && 2120 ISD::isUNINDEXEDLoad(N0.Val) && N0.hasOneUse()) { 2121 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2122 MVT::ValueType EVT = LN0->getLoadedVT(); 2123 if (!AfterLegalize || TLI.isLoadXLegal(ISD::SEXTLOAD, EVT)) { 2124 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(), 2125 LN0->getBasePtr(), LN0->getSrcValue(), 2126 LN0->getSrcValueOffset(), EVT); 2127 CombineTo(N, ExtLoad); 2128 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 2129 ExtLoad.getValue(1)); 2130 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2131 } 2132 } 2133 2134 // sext(setcc x,y,cc) -> select_cc x, y, -1, 0, cc 2135 if (N0.getOpcode() == ISD::SETCC) { 2136 SDOperand SCC = 2137 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), 2138 DAG.getConstant(~0ULL, VT), DAG.getConstant(0, VT), 2139 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 2140 if (SCC.Val) return SCC; 2141 } 2142 2143 return SDOperand(); 2144} 2145 2146SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) { 2147 SDOperand N0 = N->getOperand(0); 2148 MVT::ValueType VT = N->getValueType(0); 2149 2150 // fold (zext c1) -> c1 2151 if (isa<ConstantSDNode>(N0)) 2152 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0); 2153 // fold (zext (zext x)) -> (zext x) 2154 // fold (zext (aext x)) -> (zext x) 2155 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 2156 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0)); 2157 2158 // fold (zext (truncate (load x))) -> (zext (smaller load x)) 2159 // fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n))) 2160 if (N0.getOpcode() == ISD::TRUNCATE) { 2161 SDOperand NarrowLoad = ReduceLoadWidth(N0.Val); 2162 if (NarrowLoad.Val) { 2163 if (NarrowLoad.Val != N0.Val) 2164 CombineTo(N0.Val, NarrowLoad); 2165 return DAG.getNode(ISD::ZERO_EXTEND, VT, NarrowLoad); 2166 } 2167 } 2168 2169 // fold (zext (truncate x)) -> (and x, mask) 2170 if (N0.getOpcode() == ISD::TRUNCATE && 2171 (!AfterLegalize || TLI.isOperationLegal(ISD::AND, VT))) { 2172 SDOperand Op = N0.getOperand(0); 2173 if (Op.getValueType() < VT) { 2174 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op); 2175 } else if (Op.getValueType() > VT) { 2176 Op = DAG.getNode(ISD::TRUNCATE, VT, Op); 2177 } 2178 return DAG.getZeroExtendInReg(Op, N0.getValueType()); 2179 } 2180 2181 // fold (zext (and (trunc x), cst)) -> (and x, cst). 2182 if (N0.getOpcode() == ISD::AND && 2183 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 2184 N0.getOperand(1).getOpcode() == ISD::Constant) { 2185 SDOperand X = N0.getOperand(0).getOperand(0); 2186 if (X.getValueType() < VT) { 2187 X = DAG.getNode(ISD::ANY_EXTEND, VT, X); 2188 } else if (X.getValueType() > VT) { 2189 X = DAG.getNode(ISD::TRUNCATE, VT, X); 2190 } 2191 uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 2192 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT)); 2193 } 2194 2195 // fold (zext (load x)) -> (zext (truncate (zextload x))) 2196 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() && 2197 (!AfterLegalize||TLI.isLoadXLegal(ISD::ZEXTLOAD, N0.getValueType()))) { 2198 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2199 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), 2200 LN0->getBasePtr(), LN0->getSrcValue(), 2201 LN0->getSrcValueOffset(), 2202 N0.getValueType()); 2203 CombineTo(N, ExtLoad); 2204 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 2205 ExtLoad.getValue(1)); 2206 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2207 } 2208 2209 // fold (zext (zextload x)) -> (zext (truncate (zextload x))) 2210 // fold (zext ( extload x)) -> (zext (truncate (zextload x))) 2211 if ((ISD::isZEXTLoad(N0.Val) || ISD::isEXTLoad(N0.Val)) && 2212 ISD::isUNINDEXEDLoad(N0.Val) && N0.hasOneUse()) { 2213 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2214 MVT::ValueType EVT = LN0->getLoadedVT(); 2215 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, LN0->getChain(), 2216 LN0->getBasePtr(), LN0->getSrcValue(), 2217 LN0->getSrcValueOffset(), EVT); 2218 CombineTo(N, ExtLoad); 2219 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 2220 ExtLoad.getValue(1)); 2221 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2222 } 2223 2224 // zext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc 2225 if (N0.getOpcode() == ISD::SETCC) { 2226 SDOperand SCC = 2227 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), 2228 DAG.getConstant(1, VT), DAG.getConstant(0, VT), 2229 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 2230 if (SCC.Val) return SCC; 2231 } 2232 2233 return SDOperand(); 2234} 2235 2236SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) { 2237 SDOperand N0 = N->getOperand(0); 2238 MVT::ValueType VT = N->getValueType(0); 2239 2240 // fold (aext c1) -> c1 2241 if (isa<ConstantSDNode>(N0)) 2242 return DAG.getNode(ISD::ANY_EXTEND, VT, N0); 2243 // fold (aext (aext x)) -> (aext x) 2244 // fold (aext (zext x)) -> (zext x) 2245 // fold (aext (sext x)) -> (sext x) 2246 if (N0.getOpcode() == ISD::ANY_EXTEND || 2247 N0.getOpcode() == ISD::ZERO_EXTEND || 2248 N0.getOpcode() == ISD::SIGN_EXTEND) 2249 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0)); 2250 2251 // fold (aext (truncate (load x))) -> (aext (smaller load x)) 2252 // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n))) 2253 if (N0.getOpcode() == ISD::TRUNCATE) { 2254 SDOperand NarrowLoad = ReduceLoadWidth(N0.Val); 2255 if (NarrowLoad.Val) { 2256 if (NarrowLoad.Val != N0.Val) 2257 CombineTo(N0.Val, NarrowLoad); 2258 return DAG.getNode(ISD::ANY_EXTEND, VT, NarrowLoad); 2259 } 2260 } 2261 2262 // fold (aext (truncate x)) 2263 if (N0.getOpcode() == ISD::TRUNCATE) { 2264 SDOperand TruncOp = N0.getOperand(0); 2265 if (TruncOp.getValueType() == VT) 2266 return TruncOp; // x iff x size == zext size. 2267 if (TruncOp.getValueType() > VT) 2268 return DAG.getNode(ISD::TRUNCATE, VT, TruncOp); 2269 return DAG.getNode(ISD::ANY_EXTEND, VT, TruncOp); 2270 } 2271 2272 // fold (aext (and (trunc x), cst)) -> (and x, cst). 2273 if (N0.getOpcode() == ISD::AND && 2274 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 2275 N0.getOperand(1).getOpcode() == ISD::Constant) { 2276 SDOperand X = N0.getOperand(0).getOperand(0); 2277 if (X.getValueType() < VT) { 2278 X = DAG.getNode(ISD::ANY_EXTEND, VT, X); 2279 } else if (X.getValueType() > VT) { 2280 X = DAG.getNode(ISD::TRUNCATE, VT, X); 2281 } 2282 uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 2283 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT)); 2284 } 2285 2286 // fold (aext (load x)) -> (aext (truncate (extload x))) 2287 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() && 2288 (!AfterLegalize||TLI.isLoadXLegal(ISD::EXTLOAD, N0.getValueType()))) { 2289 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2290 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, LN0->getChain(), 2291 LN0->getBasePtr(), LN0->getSrcValue(), 2292 LN0->getSrcValueOffset(), 2293 N0.getValueType()); 2294 CombineTo(N, ExtLoad); 2295 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 2296 ExtLoad.getValue(1)); 2297 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2298 } 2299 2300 // fold (aext (zextload x)) -> (aext (truncate (zextload x))) 2301 // fold (aext (sextload x)) -> (aext (truncate (sextload x))) 2302 // fold (aext ( extload x)) -> (aext (truncate (extload x))) 2303 if (N0.getOpcode() == ISD::LOAD && 2304 !ISD::isNON_EXTLoad(N0.Val) && ISD::isUNINDEXEDLoad(N0.Val) && 2305 N0.hasOneUse()) { 2306 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2307 MVT::ValueType EVT = LN0->getLoadedVT(); 2308 SDOperand ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), VT, 2309 LN0->getChain(), LN0->getBasePtr(), 2310 LN0->getSrcValue(), 2311 LN0->getSrcValueOffset(), EVT); 2312 CombineTo(N, ExtLoad); 2313 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 2314 ExtLoad.getValue(1)); 2315 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2316 } 2317 2318 // aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc 2319 if (N0.getOpcode() == ISD::SETCC) { 2320 SDOperand SCC = 2321 SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), 2322 DAG.getConstant(1, VT), DAG.getConstant(0, VT), 2323 cast<CondCodeSDNode>(N0.getOperand(2))->get(), true); 2324 if (SCC.Val) 2325 return SCC; 2326 } 2327 2328 return SDOperand(); 2329} 2330 2331/// ReduceLoadWidth - If the result of a wider load is shifted to right of N 2332/// bits and then truncated to a narrower type and where N is a multiple 2333/// of number of bits of the narrower type, transform it to a narrower load 2334/// from address + N / num of bits of new type. If the result is to be 2335/// extended, also fold the extension to form a extending load. 2336SDOperand DAGCombiner::ReduceLoadWidth(SDNode *N) { 2337 unsigned Opc = N->getOpcode(); 2338 ISD::LoadExtType ExtType = ISD::NON_EXTLOAD; 2339 SDOperand N0 = N->getOperand(0); 2340 MVT::ValueType VT = N->getValueType(0); 2341 MVT::ValueType EVT = N->getValueType(0); 2342 2343 // Special case: SIGN_EXTEND_INREG is basically truncating to EVT then 2344 // extended to VT. 2345 if (Opc == ISD::SIGN_EXTEND_INREG) { 2346 ExtType = ISD::SEXTLOAD; 2347 EVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 2348 if (AfterLegalize && !TLI.isLoadXLegal(ISD::SEXTLOAD, EVT)) 2349 return SDOperand(); 2350 } 2351 2352 unsigned EVTBits = MVT::getSizeInBits(EVT); 2353 unsigned ShAmt = 0; 2354 bool CombineSRL = false; 2355 if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) { 2356 if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 2357 ShAmt = N01->getValue(); 2358 // Is the shift amount a multiple of size of VT? 2359 if ((ShAmt & (EVTBits-1)) == 0) { 2360 N0 = N0.getOperand(0); 2361 if (MVT::getSizeInBits(N0.getValueType()) <= EVTBits) 2362 return SDOperand(); 2363 CombineSRL = true; 2364 } 2365 } 2366 } 2367 2368 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() && 2369 // Do not allow folding to i1 here. i1 is implicitly stored in memory in 2370 // zero extended form: by shrinking the load, we lose track of the fact 2371 // that it is already zero extended. 2372 // FIXME: This should be reevaluated. 2373 VT != MVT::i1) { 2374 assert(MVT::getSizeInBits(N0.getValueType()) > EVTBits && 2375 "Cannot truncate to larger type!"); 2376 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2377 MVT::ValueType PtrType = N0.getOperand(1).getValueType(); 2378 // For big endian targets, we need to adjust the offset to the pointer to 2379 // load the correct bytes. 2380 if (!TLI.isLittleEndian()) 2381 ShAmt = MVT::getSizeInBits(N0.getValueType()) - ShAmt - EVTBits; 2382 uint64_t PtrOff = ShAmt / 8; 2383 SDOperand NewPtr = DAG.getNode(ISD::ADD, PtrType, LN0->getBasePtr(), 2384 DAG.getConstant(PtrOff, PtrType)); 2385 AddToWorkList(NewPtr.Val); 2386 SDOperand Load = (ExtType == ISD::NON_EXTLOAD) 2387 ? DAG.getLoad(VT, LN0->getChain(), NewPtr, 2388 LN0->getSrcValue(), LN0->getSrcValueOffset()) 2389 : DAG.getExtLoad(ExtType, VT, LN0->getChain(), NewPtr, 2390 LN0->getSrcValue(), LN0->getSrcValueOffset(), EVT); 2391 AddToWorkList(N); 2392 if (CombineSRL) { 2393 std::vector<SDNode*> NowDead; 2394 DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1), NowDead); 2395 CombineTo(N->getOperand(0).Val, Load); 2396 } else 2397 CombineTo(N0.Val, Load, Load.getValue(1)); 2398 if (ShAmt) { 2399 if (Opc == ISD::SIGN_EXTEND_INREG) 2400 return DAG.getNode(Opc, VT, Load, N->getOperand(1)); 2401 else 2402 return DAG.getNode(Opc, VT, Load); 2403 } 2404 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2405 } 2406 2407 return SDOperand(); 2408} 2409 2410 2411SDOperand DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) { 2412 SDOperand N0 = N->getOperand(0); 2413 SDOperand N1 = N->getOperand(1); 2414 MVT::ValueType VT = N->getValueType(0); 2415 MVT::ValueType EVT = cast<VTSDNode>(N1)->getVT(); 2416 unsigned EVTBits = MVT::getSizeInBits(EVT); 2417 2418 // fold (sext_in_reg c1) -> c1 2419 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF) 2420 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0, N1); 2421 2422 // If the input is already sign extended, just drop the extension. 2423 if (TLI.ComputeNumSignBits(N0) >= MVT::getSizeInBits(VT)-EVTBits+1) 2424 return N0; 2425 2426 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2 2427 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && 2428 EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) { 2429 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1); 2430 } 2431 2432 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero. 2433 if (TLI.MaskedValueIsZero(N0, 1ULL << (EVTBits-1))) 2434 return DAG.getZeroExtendInReg(N0, EVT); 2435 2436 // fold operands of sext_in_reg based on knowledge that the top bits are not 2437 // demanded. 2438 if (SimplifyDemandedBits(SDOperand(N, 0))) 2439 return SDOperand(N, 0); 2440 2441 // fold (sext_in_reg (load x)) -> (smaller sextload x) 2442 // fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits)) 2443 SDOperand NarrowLoad = ReduceLoadWidth(N); 2444 if (NarrowLoad.Val) 2445 return NarrowLoad; 2446 2447 // fold (sext_in_reg (srl X, 24), i8) -> sra X, 24 2448 // fold (sext_in_reg (srl X, 23), i8) -> sra X, 23 iff possible. 2449 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above. 2450 if (N0.getOpcode() == ISD::SRL) { 2451 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 2452 if (ShAmt->getValue()+EVTBits <= MVT::getSizeInBits(VT)) { 2453 // We can turn this into an SRA iff the input to the SRL is already sign 2454 // extended enough. 2455 unsigned InSignBits = TLI.ComputeNumSignBits(N0.getOperand(0)); 2456 if (MVT::getSizeInBits(VT)-(ShAmt->getValue()+EVTBits) < InSignBits) 2457 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), N0.getOperand(1)); 2458 } 2459 } 2460 2461 // fold (sext_inreg (extload x)) -> (sextload x) 2462 if (ISD::isEXTLoad(N0.Val) && 2463 ISD::isUNINDEXEDLoad(N0.Val) && 2464 EVT == cast<LoadSDNode>(N0)->getLoadedVT() && 2465 (!AfterLegalize || TLI.isLoadXLegal(ISD::SEXTLOAD, EVT))) { 2466 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2467 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(), 2468 LN0->getBasePtr(), LN0->getSrcValue(), 2469 LN0->getSrcValueOffset(), EVT); 2470 CombineTo(N, ExtLoad); 2471 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1)); 2472 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2473 } 2474 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use 2475 if (ISD::isZEXTLoad(N0.Val) && ISD::isUNINDEXEDLoad(N0.Val) && 2476 N0.hasOneUse() && 2477 EVT == cast<LoadSDNode>(N0)->getLoadedVT() && 2478 (!AfterLegalize || TLI.isLoadXLegal(ISD::SEXTLOAD, EVT))) { 2479 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2480 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, LN0->getChain(), 2481 LN0->getBasePtr(), LN0->getSrcValue(), 2482 LN0->getSrcValueOffset(), EVT); 2483 CombineTo(N, ExtLoad); 2484 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1)); 2485 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2486 } 2487 return SDOperand(); 2488} 2489 2490SDOperand DAGCombiner::visitTRUNCATE(SDNode *N) { 2491 SDOperand N0 = N->getOperand(0); 2492 MVT::ValueType VT = N->getValueType(0); 2493 2494 // noop truncate 2495 if (N0.getValueType() == N->getValueType(0)) 2496 return N0; 2497 // fold (truncate c1) -> c1 2498 if (isa<ConstantSDNode>(N0)) 2499 return DAG.getNode(ISD::TRUNCATE, VT, N0); 2500 // fold (truncate (truncate x)) -> (truncate x) 2501 if (N0.getOpcode() == ISD::TRUNCATE) 2502 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0)); 2503 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x 2504 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND|| 2505 N0.getOpcode() == ISD::ANY_EXTEND) { 2506 if (N0.getOperand(0).getValueType() < VT) 2507 // if the source is smaller than the dest, we still need an extend 2508 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0)); 2509 else if (N0.getOperand(0).getValueType() > VT) 2510 // if the source is larger than the dest, than we just need the truncate 2511 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0)); 2512 else 2513 // if the source and dest are the same type, we can drop both the extend 2514 // and the truncate 2515 return N0.getOperand(0); 2516 } 2517 2518 // fold (truncate (load x)) -> (smaller load x) 2519 // fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits)) 2520 return ReduceLoadWidth(N); 2521} 2522 2523SDOperand DAGCombiner::visitBIT_CONVERT(SDNode *N) { 2524 SDOperand N0 = N->getOperand(0); 2525 MVT::ValueType VT = N->getValueType(0); 2526 2527 // If the input is a constant, let getNode() fold it. 2528 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) { 2529 SDOperand Res = DAG.getNode(ISD::BIT_CONVERT, VT, N0); 2530 if (Res.Val != N) return Res; 2531 } 2532 2533 if (N0.getOpcode() == ISD::BIT_CONVERT) // conv(conv(x,t1),t2) -> conv(x,t2) 2534 return DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0)); 2535 2536 // fold (conv (load x)) -> (load (conv*)x) 2537 // FIXME: These xforms need to know that the resultant load doesn't need a 2538 // higher alignment than the original! 2539 if (0 && ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse()) { 2540 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2541 SDOperand Load = DAG.getLoad(VT, LN0->getChain(), LN0->getBasePtr(), 2542 LN0->getSrcValue(), LN0->getSrcValueOffset()); 2543 AddToWorkList(N); 2544 CombineTo(N0.Val, DAG.getNode(ISD::BIT_CONVERT, N0.getValueType(), Load), 2545 Load.getValue(1)); 2546 return Load; 2547 } 2548 2549 return SDOperand(); 2550} 2551 2552SDOperand DAGCombiner::visitVBIT_CONVERT(SDNode *N) { 2553 SDOperand N0 = N->getOperand(0); 2554 MVT::ValueType VT = N->getValueType(0); 2555 2556 // If the input is a VBUILD_VECTOR with all constant elements, fold this now. 2557 // First check to see if this is all constant. 2558 if (N0.getOpcode() == ISD::VBUILD_VECTOR && N0.Val->hasOneUse() && 2559 VT == MVT::Vector) { 2560 bool isSimple = true; 2561 for (unsigned i = 0, e = N0.getNumOperands()-2; i != e; ++i) 2562 if (N0.getOperand(i).getOpcode() != ISD::UNDEF && 2563 N0.getOperand(i).getOpcode() != ISD::Constant && 2564 N0.getOperand(i).getOpcode() != ISD::ConstantFP) { 2565 isSimple = false; 2566 break; 2567 } 2568 2569 MVT::ValueType DestEltVT = cast<VTSDNode>(N->getOperand(2))->getVT(); 2570 if (isSimple && !MVT::isVector(DestEltVT)) { 2571 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(N0.Val, DestEltVT); 2572 } 2573 } 2574 2575 return SDOperand(); 2576} 2577 2578/// ConstantFoldVBIT_CONVERTofVBUILD_VECTOR - We know that BV is a vbuild_vector 2579/// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the 2580/// destination element value type. 2581SDOperand DAGCombiner:: 2582ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *BV, MVT::ValueType DstEltVT) { 2583 MVT::ValueType SrcEltVT = BV->getOperand(0).getValueType(); 2584 2585 // If this is already the right type, we're done. 2586 if (SrcEltVT == DstEltVT) return SDOperand(BV, 0); 2587 2588 unsigned SrcBitSize = MVT::getSizeInBits(SrcEltVT); 2589 unsigned DstBitSize = MVT::getSizeInBits(DstEltVT); 2590 2591 // If this is a conversion of N elements of one type to N elements of another 2592 // type, convert each element. This handles FP<->INT cases. 2593 if (SrcBitSize == DstBitSize) { 2594 SmallVector<SDOperand, 8> Ops; 2595 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) { 2596 Ops.push_back(DAG.getNode(ISD::BIT_CONVERT, DstEltVT, BV->getOperand(i))); 2597 AddToWorkList(Ops.back().Val); 2598 } 2599 Ops.push_back(*(BV->op_end()-2)); // Add num elements. 2600 Ops.push_back(DAG.getValueType(DstEltVT)); 2601 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size()); 2602 } 2603 2604 // Otherwise, we're growing or shrinking the elements. To avoid having to 2605 // handle annoying details of growing/shrinking FP values, we convert them to 2606 // int first. 2607 if (MVT::isFloatingPoint(SrcEltVT)) { 2608 // Convert the input float vector to a int vector where the elements are the 2609 // same sizes. 2610 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!"); 2611 MVT::ValueType IntVT = SrcEltVT == MVT::f32 ? MVT::i32 : MVT::i64; 2612 BV = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, IntVT).Val; 2613 SrcEltVT = IntVT; 2614 } 2615 2616 // Now we know the input is an integer vector. If the output is a FP type, 2617 // convert to integer first, then to FP of the right size. 2618 if (MVT::isFloatingPoint(DstEltVT)) { 2619 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!"); 2620 MVT::ValueType TmpVT = DstEltVT == MVT::f32 ? MVT::i32 : MVT::i64; 2621 SDNode *Tmp = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, TmpVT).Val; 2622 2623 // Next, convert to FP elements of the same size. 2624 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(Tmp, DstEltVT); 2625 } 2626 2627 // Okay, we know the src/dst types are both integers of differing types. 2628 // Handling growing first. 2629 assert(MVT::isInteger(SrcEltVT) && MVT::isInteger(DstEltVT)); 2630 if (SrcBitSize < DstBitSize) { 2631 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize; 2632 2633 SmallVector<SDOperand, 8> Ops; 2634 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; 2635 i += NumInputsPerOutput) { 2636 bool isLE = TLI.isLittleEndian(); 2637 uint64_t NewBits = 0; 2638 bool EltIsUndef = true; 2639 for (unsigned j = 0; j != NumInputsPerOutput; ++j) { 2640 // Shift the previously computed bits over. 2641 NewBits <<= SrcBitSize; 2642 SDOperand Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j)); 2643 if (Op.getOpcode() == ISD::UNDEF) continue; 2644 EltIsUndef = false; 2645 2646 NewBits |= cast<ConstantSDNode>(Op)->getValue(); 2647 } 2648 2649 if (EltIsUndef) 2650 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT)); 2651 else 2652 Ops.push_back(DAG.getConstant(NewBits, DstEltVT)); 2653 } 2654 2655 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements. 2656 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size. 2657 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size()); 2658 } 2659 2660 // Finally, this must be the case where we are shrinking elements: each input 2661 // turns into multiple outputs. 2662 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize; 2663 SmallVector<SDOperand, 8> Ops; 2664 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) { 2665 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) { 2666 for (unsigned j = 0; j != NumOutputsPerInput; ++j) 2667 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT)); 2668 continue; 2669 } 2670 uint64_t OpVal = cast<ConstantSDNode>(BV->getOperand(i))->getValue(); 2671 2672 for (unsigned j = 0; j != NumOutputsPerInput; ++j) { 2673 unsigned ThisVal = OpVal & ((1ULL << DstBitSize)-1); 2674 OpVal >>= DstBitSize; 2675 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT)); 2676 } 2677 2678 // For big endian targets, swap the order of the pieces of each element. 2679 if (!TLI.isLittleEndian()) 2680 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end()); 2681 } 2682 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements. 2683 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size. 2684 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size()); 2685} 2686 2687 2688 2689SDOperand DAGCombiner::visitFADD(SDNode *N) { 2690 SDOperand N0 = N->getOperand(0); 2691 SDOperand N1 = N->getOperand(1); 2692 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2693 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2694 MVT::ValueType VT = N->getValueType(0); 2695 2696 // fold (fadd c1, c2) -> c1+c2 2697 if (N0CFP && N1CFP) 2698 return DAG.getNode(ISD::FADD, VT, N0, N1); 2699 // canonicalize constant to RHS 2700 if (N0CFP && !N1CFP) 2701 return DAG.getNode(ISD::FADD, VT, N1, N0); 2702 // fold (A + (-B)) -> A-B 2703 if (N1.getOpcode() == ISD::FNEG) 2704 return DAG.getNode(ISD::FSUB, VT, N0, N1.getOperand(0)); 2705 // fold ((-A) + B) -> B-A 2706 if (N0.getOpcode() == ISD::FNEG) 2707 return DAG.getNode(ISD::FSUB, VT, N1, N0.getOperand(0)); 2708 2709 // If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2)) 2710 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FADD && 2711 N0.Val->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1))) 2712 return DAG.getNode(ISD::FADD, VT, N0.getOperand(0), 2713 DAG.getNode(ISD::FADD, VT, N0.getOperand(1), N1)); 2714 2715 return SDOperand(); 2716} 2717 2718SDOperand DAGCombiner::visitFSUB(SDNode *N) { 2719 SDOperand N0 = N->getOperand(0); 2720 SDOperand N1 = N->getOperand(1); 2721 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2722 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2723 MVT::ValueType VT = N->getValueType(0); 2724 2725 // fold (fsub c1, c2) -> c1-c2 2726 if (N0CFP && N1CFP) 2727 return DAG.getNode(ISD::FSUB, VT, N0, N1); 2728 // fold (A-(-B)) -> A+B 2729 if (N1.getOpcode() == ISD::FNEG) 2730 return DAG.getNode(ISD::FADD, VT, N0, N1.getOperand(0)); 2731 return SDOperand(); 2732} 2733 2734SDOperand DAGCombiner::visitFMUL(SDNode *N) { 2735 SDOperand N0 = N->getOperand(0); 2736 SDOperand N1 = N->getOperand(1); 2737 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2738 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2739 MVT::ValueType VT = N->getValueType(0); 2740 2741 // fold (fmul c1, c2) -> c1*c2 2742 if (N0CFP && N1CFP) 2743 return DAG.getNode(ISD::FMUL, VT, N0, N1); 2744 // canonicalize constant to RHS 2745 if (N0CFP && !N1CFP) 2746 return DAG.getNode(ISD::FMUL, VT, N1, N0); 2747 // fold (fmul X, 2.0) -> (fadd X, X) 2748 if (N1CFP && N1CFP->isExactlyValue(+2.0)) 2749 return DAG.getNode(ISD::FADD, VT, N0, N0); 2750 2751 // If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2)) 2752 if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FMUL && 2753 N0.Val->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1))) 2754 return DAG.getNode(ISD::FMUL, VT, N0.getOperand(0), 2755 DAG.getNode(ISD::FMUL, VT, N0.getOperand(1), N1)); 2756 2757 return SDOperand(); 2758} 2759 2760SDOperand DAGCombiner::visitFDIV(SDNode *N) { 2761 SDOperand N0 = N->getOperand(0); 2762 SDOperand N1 = N->getOperand(1); 2763 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2764 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2765 MVT::ValueType VT = N->getValueType(0); 2766 2767 // fold (fdiv c1, c2) -> c1/c2 2768 if (N0CFP && N1CFP) 2769 return DAG.getNode(ISD::FDIV, VT, N0, N1); 2770 return SDOperand(); 2771} 2772 2773SDOperand DAGCombiner::visitFREM(SDNode *N) { 2774 SDOperand N0 = N->getOperand(0); 2775 SDOperand N1 = N->getOperand(1); 2776 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2777 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2778 MVT::ValueType VT = N->getValueType(0); 2779 2780 // fold (frem c1, c2) -> fmod(c1,c2) 2781 if (N0CFP && N1CFP) 2782 return DAG.getNode(ISD::FREM, VT, N0, N1); 2783 return SDOperand(); 2784} 2785 2786SDOperand DAGCombiner::visitFCOPYSIGN(SDNode *N) { 2787 SDOperand N0 = N->getOperand(0); 2788 SDOperand N1 = N->getOperand(1); 2789 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2790 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2791 MVT::ValueType VT = N->getValueType(0); 2792 2793 if (N0CFP && N1CFP) // Constant fold 2794 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1); 2795 2796 if (N1CFP) { 2797 // copysign(x, c1) -> fabs(x) iff ispos(c1) 2798 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1) 2799 union { 2800 double d; 2801 int64_t i; 2802 } u; 2803 u.d = N1CFP->getValue(); 2804 if (u.i >= 0) 2805 return DAG.getNode(ISD::FABS, VT, N0); 2806 else 2807 return DAG.getNode(ISD::FNEG, VT, DAG.getNode(ISD::FABS, VT, N0)); 2808 } 2809 2810 // copysign(fabs(x), y) -> copysign(x, y) 2811 // copysign(fneg(x), y) -> copysign(x, y) 2812 // copysign(copysign(x,z), y) -> copysign(x, y) 2813 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG || 2814 N0.getOpcode() == ISD::FCOPYSIGN) 2815 return DAG.getNode(ISD::FCOPYSIGN, VT, N0.getOperand(0), N1); 2816 2817 // copysign(x, abs(y)) -> abs(x) 2818 if (N1.getOpcode() == ISD::FABS) 2819 return DAG.getNode(ISD::FABS, VT, N0); 2820 2821 // copysign(x, copysign(y,z)) -> copysign(x, z) 2822 if (N1.getOpcode() == ISD::FCOPYSIGN) 2823 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(1)); 2824 2825 // copysign(x, fp_extend(y)) -> copysign(x, y) 2826 // copysign(x, fp_round(y)) -> copysign(x, y) 2827 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND) 2828 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(0)); 2829 2830 return SDOperand(); 2831} 2832 2833 2834 2835SDOperand DAGCombiner::visitSINT_TO_FP(SDNode *N) { 2836 SDOperand N0 = N->getOperand(0); 2837 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2838 MVT::ValueType VT = N->getValueType(0); 2839 2840 // fold (sint_to_fp c1) -> c1fp 2841 if (N0C) 2842 return DAG.getNode(ISD::SINT_TO_FP, VT, N0); 2843 return SDOperand(); 2844} 2845 2846SDOperand DAGCombiner::visitUINT_TO_FP(SDNode *N) { 2847 SDOperand N0 = N->getOperand(0); 2848 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2849 MVT::ValueType VT = N->getValueType(0); 2850 2851 // fold (uint_to_fp c1) -> c1fp 2852 if (N0C) 2853 return DAG.getNode(ISD::UINT_TO_FP, VT, N0); 2854 return SDOperand(); 2855} 2856 2857SDOperand DAGCombiner::visitFP_TO_SINT(SDNode *N) { 2858 SDOperand N0 = N->getOperand(0); 2859 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2860 MVT::ValueType VT = N->getValueType(0); 2861 2862 // fold (fp_to_sint c1fp) -> c1 2863 if (N0CFP) 2864 return DAG.getNode(ISD::FP_TO_SINT, VT, N0); 2865 return SDOperand(); 2866} 2867 2868SDOperand DAGCombiner::visitFP_TO_UINT(SDNode *N) { 2869 SDOperand N0 = N->getOperand(0); 2870 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2871 MVT::ValueType VT = N->getValueType(0); 2872 2873 // fold (fp_to_uint c1fp) -> c1 2874 if (N0CFP) 2875 return DAG.getNode(ISD::FP_TO_UINT, VT, N0); 2876 return SDOperand(); 2877} 2878 2879SDOperand DAGCombiner::visitFP_ROUND(SDNode *N) { 2880 SDOperand N0 = N->getOperand(0); 2881 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2882 MVT::ValueType VT = N->getValueType(0); 2883 2884 // fold (fp_round c1fp) -> c1fp 2885 if (N0CFP) 2886 return DAG.getNode(ISD::FP_ROUND, VT, N0); 2887 2888 // fold (fp_round (fp_extend x)) -> x 2889 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType()) 2890 return N0.getOperand(0); 2891 2892 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y) 2893 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.Val->hasOneUse()) { 2894 SDOperand Tmp = DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0)); 2895 AddToWorkList(Tmp.Val); 2896 return DAG.getNode(ISD::FCOPYSIGN, VT, Tmp, N0.getOperand(1)); 2897 } 2898 2899 return SDOperand(); 2900} 2901 2902SDOperand DAGCombiner::visitFP_ROUND_INREG(SDNode *N) { 2903 SDOperand N0 = N->getOperand(0); 2904 MVT::ValueType VT = N->getValueType(0); 2905 MVT::ValueType EVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 2906 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2907 2908 // fold (fp_round_inreg c1fp) -> c1fp 2909 if (N0CFP) { 2910 SDOperand Round = DAG.getConstantFP(N0CFP->getValue(), EVT); 2911 return DAG.getNode(ISD::FP_EXTEND, VT, Round); 2912 } 2913 return SDOperand(); 2914} 2915 2916SDOperand DAGCombiner::visitFP_EXTEND(SDNode *N) { 2917 SDOperand N0 = N->getOperand(0); 2918 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2919 MVT::ValueType VT = N->getValueType(0); 2920 2921 // fold (fp_extend c1fp) -> c1fp 2922 if (N0CFP) 2923 return DAG.getNode(ISD::FP_EXTEND, VT, N0); 2924 2925 // fold (fpext (load x)) -> (fpext (fpround (extload x))) 2926 if (ISD::isNON_EXTLoad(N0.Val) && N0.hasOneUse() && 2927 (!AfterLegalize||TLI.isLoadXLegal(ISD::EXTLOAD, N0.getValueType()))) { 2928 LoadSDNode *LN0 = cast<LoadSDNode>(N0); 2929 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, LN0->getChain(), 2930 LN0->getBasePtr(), LN0->getSrcValue(), 2931 LN0->getSrcValueOffset(), 2932 N0.getValueType()); 2933 CombineTo(N, ExtLoad); 2934 CombineTo(N0.Val, DAG.getNode(ISD::FP_ROUND, N0.getValueType(), ExtLoad), 2935 ExtLoad.getValue(1)); 2936 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2937 } 2938 2939 2940 return SDOperand(); 2941} 2942 2943SDOperand DAGCombiner::visitFNEG(SDNode *N) { 2944 SDOperand N0 = N->getOperand(0); 2945 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2946 MVT::ValueType VT = N->getValueType(0); 2947 2948 // fold (fneg c1) -> -c1 2949 if (N0CFP) 2950 return DAG.getNode(ISD::FNEG, VT, N0); 2951 // fold (fneg (sub x, y)) -> (sub y, x) 2952 if (N0.getOpcode() == ISD::SUB) 2953 return DAG.getNode(ISD::SUB, VT, N0.getOperand(1), N0.getOperand(0)); 2954 // fold (fneg (fneg x)) -> x 2955 if (N0.getOpcode() == ISD::FNEG) 2956 return N0.getOperand(0); 2957 return SDOperand(); 2958} 2959 2960SDOperand DAGCombiner::visitFABS(SDNode *N) { 2961 SDOperand N0 = N->getOperand(0); 2962 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2963 MVT::ValueType VT = N->getValueType(0); 2964 2965 // fold (fabs c1) -> fabs(c1) 2966 if (N0CFP) 2967 return DAG.getNode(ISD::FABS, VT, N0); 2968 // fold (fabs (fabs x)) -> (fabs x) 2969 if (N0.getOpcode() == ISD::FABS) 2970 return N->getOperand(0); 2971 // fold (fabs (fneg x)) -> (fabs x) 2972 // fold (fabs (fcopysign x, y)) -> (fabs x) 2973 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN) 2974 return DAG.getNode(ISD::FABS, VT, N0.getOperand(0)); 2975 2976 return SDOperand(); 2977} 2978 2979SDOperand DAGCombiner::visitBRCOND(SDNode *N) { 2980 SDOperand Chain = N->getOperand(0); 2981 SDOperand N1 = N->getOperand(1); 2982 SDOperand N2 = N->getOperand(2); 2983 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2984 2985 // never taken branch, fold to chain 2986 if (N1C && N1C->isNullValue()) 2987 return Chain; 2988 // unconditional branch 2989 if (N1C && N1C->getValue() == 1) 2990 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2); 2991 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal 2992 // on the target. 2993 if (N1.getOpcode() == ISD::SETCC && 2994 TLI.isOperationLegal(ISD::BR_CC, MVT::Other)) { 2995 return DAG.getNode(ISD::BR_CC, MVT::Other, Chain, N1.getOperand(2), 2996 N1.getOperand(0), N1.getOperand(1), N2); 2997 } 2998 return SDOperand(); 2999} 3000 3001// Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB. 3002// 3003SDOperand DAGCombiner::visitBR_CC(SDNode *N) { 3004 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1)); 3005 SDOperand CondLHS = N->getOperand(2), CondRHS = N->getOperand(3); 3006 3007 // Use SimplifySetCC to simplify SETCC's. 3008 SDOperand Simp = SimplifySetCC(MVT::i1, CondLHS, CondRHS, CC->get(), false); 3009 if (Simp.Val) AddToWorkList(Simp.Val); 3010 3011 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.Val); 3012 3013 // fold br_cc true, dest -> br dest (unconditional branch) 3014 if (SCCC && SCCC->getValue()) 3015 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0), 3016 N->getOperand(4)); 3017 // fold br_cc false, dest -> unconditional fall through 3018 if (SCCC && SCCC->isNullValue()) 3019 return N->getOperand(0); 3020 3021 // fold to a simpler setcc 3022 if (Simp.Val && Simp.getOpcode() == ISD::SETCC) 3023 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0), 3024 Simp.getOperand(2), Simp.getOperand(0), 3025 Simp.getOperand(1), N->getOperand(4)); 3026 return SDOperand(); 3027} 3028 3029 3030/// CombineToPreIndexedLoadStore - Try turning a load / store and a 3031/// pre-indexed load / store when the base pointer is a add or subtract 3032/// and it has other uses besides the load / store. After the 3033/// transformation, the new indexed load / store has effectively folded 3034/// the add / subtract in and all of its other uses are redirected to the 3035/// new load / store. 3036bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) { 3037 if (!AfterLegalize) 3038 return false; 3039 3040 bool isLoad = true; 3041 SDOperand Ptr; 3042 MVT::ValueType VT; 3043 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 3044 if (LD->getAddressingMode() != ISD::UNINDEXED) 3045 return false; 3046 VT = LD->getLoadedVT(); 3047 if (!TLI.isIndexedLoadLegal(ISD::PRE_INC, VT) && 3048 !TLI.isIndexedLoadLegal(ISD::PRE_DEC, VT)) 3049 return false; 3050 Ptr = LD->getBasePtr(); 3051 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 3052 if (ST->getAddressingMode() != ISD::UNINDEXED) 3053 return false; 3054 VT = ST->getStoredVT(); 3055 if (!TLI.isIndexedStoreLegal(ISD::PRE_INC, VT) && 3056 !TLI.isIndexedStoreLegal(ISD::PRE_DEC, VT)) 3057 return false; 3058 Ptr = ST->getBasePtr(); 3059 isLoad = false; 3060 } else 3061 return false; 3062 3063 // If the pointer is not an add/sub, or if it doesn't have multiple uses, bail 3064 // out. There is no reason to make this a preinc/predec. 3065 if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) || 3066 Ptr.Val->hasOneUse()) 3067 return false; 3068 3069 // Ask the target to do addressing mode selection. 3070 SDOperand BasePtr; 3071 SDOperand Offset; 3072 ISD::MemIndexedMode AM = ISD::UNINDEXED; 3073 if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG)) 3074 return false; 3075 3076 // Try turning it into a pre-indexed load / store except when: 3077 // 1) The base is a frame index. 3078 // 2) If N is a store and the ptr is either the same as or is a 3079 // predecessor of the value being stored. 3080 // 3) Another use of base ptr is a predecessor of N. If ptr is folded 3081 // that would create a cycle. 3082 // 4) All uses are load / store ops that use it as base ptr. 3083 3084 // Check #1. Preinc'ing a frame index would require copying the stack pointer 3085 // (plus the implicit offset) to a register to preinc anyway. 3086 if (isa<FrameIndexSDNode>(BasePtr)) 3087 return false; 3088 3089 // Check #2. 3090 if (!isLoad) { 3091 SDOperand Val = cast<StoreSDNode>(N)->getValue(); 3092 if (Val == Ptr || Ptr.Val->isPredecessor(Val.Val)) 3093 return false; 3094 } 3095 3096 // Now check for #2 and #3. 3097 bool RealUse = false; 3098 for (SDNode::use_iterator I = Ptr.Val->use_begin(), 3099 E = Ptr.Val->use_end(); I != E; ++I) { 3100 SDNode *Use = *I; 3101 if (Use == N) 3102 continue; 3103 if (Use->isPredecessor(N)) 3104 return false; 3105 3106 if (!((Use->getOpcode() == ISD::LOAD && 3107 cast<LoadSDNode>(Use)->getBasePtr() == Ptr) || 3108 (Use->getOpcode() == ISD::STORE) && 3109 cast<StoreSDNode>(Use)->getBasePtr() == Ptr)) 3110 RealUse = true; 3111 } 3112 if (!RealUse) 3113 return false; 3114 3115 SDOperand Result; 3116 if (isLoad) 3117 Result = DAG.getIndexedLoad(SDOperand(N,0), BasePtr, Offset, AM); 3118 else 3119 Result = DAG.getIndexedStore(SDOperand(N,0), BasePtr, Offset, AM); 3120 ++PreIndexedNodes; 3121 ++NodesCombined; 3122 DOUT << "\nReplacing.4 "; DEBUG(N->dump()); 3123 DOUT << "\nWith: "; DEBUG(Result.Val->dump(&DAG)); 3124 DOUT << '\n'; 3125 std::vector<SDNode*> NowDead; 3126 if (isLoad) { 3127 DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 0), Result.getValue(0), 3128 NowDead); 3129 DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 1), Result.getValue(2), 3130 NowDead); 3131 } else { 3132 DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 0), Result.getValue(1), 3133 NowDead); 3134 } 3135 3136 // Nodes can end up on the worklist more than once. Make sure we do 3137 // not process a node that has been replaced. 3138 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 3139 removeFromWorkList(NowDead[i]); 3140 // Finally, since the node is now dead, remove it from the graph. 3141 DAG.DeleteNode(N); 3142 3143 // Replace the uses of Ptr with uses of the updated base value. 3144 DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(isLoad ? 1 : 0), 3145 NowDead); 3146 removeFromWorkList(Ptr.Val); 3147 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 3148 removeFromWorkList(NowDead[i]); 3149 DAG.DeleteNode(Ptr.Val); 3150 3151 return true; 3152} 3153 3154/// CombineToPostIndexedLoadStore - Try combine a load / store with a 3155/// add / sub of the base pointer node into a post-indexed load / store. 3156/// The transformation folded the add / subtract into the new indexed 3157/// load / store effectively and all of its uses are redirected to the 3158/// new load / store. 3159bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) { 3160 if (!AfterLegalize) 3161 return false; 3162 3163 bool isLoad = true; 3164 SDOperand Ptr; 3165 MVT::ValueType VT; 3166 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 3167 if (LD->getAddressingMode() != ISD::UNINDEXED) 3168 return false; 3169 VT = LD->getLoadedVT(); 3170 if (!TLI.isIndexedLoadLegal(ISD::POST_INC, VT) && 3171 !TLI.isIndexedLoadLegal(ISD::POST_DEC, VT)) 3172 return false; 3173 Ptr = LD->getBasePtr(); 3174 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 3175 if (ST->getAddressingMode() != ISD::UNINDEXED) 3176 return false; 3177 VT = ST->getStoredVT(); 3178 if (!TLI.isIndexedStoreLegal(ISD::POST_INC, VT) && 3179 !TLI.isIndexedStoreLegal(ISD::POST_DEC, VT)) 3180 return false; 3181 Ptr = ST->getBasePtr(); 3182 isLoad = false; 3183 } else 3184 return false; 3185 3186 if (Ptr.Val->hasOneUse()) 3187 return false; 3188 3189 for (SDNode::use_iterator I = Ptr.Val->use_begin(), 3190 E = Ptr.Val->use_end(); I != E; ++I) { 3191 SDNode *Op = *I; 3192 if (Op == N || 3193 (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB)) 3194 continue; 3195 3196 SDOperand BasePtr; 3197 SDOperand Offset; 3198 ISD::MemIndexedMode AM = ISD::UNINDEXED; 3199 if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) { 3200 if (Ptr == Offset) 3201 std::swap(BasePtr, Offset); 3202 if (Ptr != BasePtr) 3203 continue; 3204 3205 // Try turning it into a post-indexed load / store except when 3206 // 1) All uses are load / store ops that use it as base ptr. 3207 // 2) Op must be independent of N, i.e. Op is neither a predecessor 3208 // nor a successor of N. Otherwise, if Op is folded that would 3209 // create a cycle. 3210 3211 // Check for #1. 3212 bool TryNext = false; 3213 for (SDNode::use_iterator II = BasePtr.Val->use_begin(), 3214 EE = BasePtr.Val->use_end(); II != EE; ++II) { 3215 SDNode *Use = *II; 3216 if (Use == Ptr.Val) 3217 continue; 3218 3219 // If all the uses are load / store addresses, then don't do the 3220 // transformation. 3221 if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB){ 3222 bool RealUse = false; 3223 for (SDNode::use_iterator III = Use->use_begin(), 3224 EEE = Use->use_end(); III != EEE; ++III) { 3225 SDNode *UseUse = *III; 3226 if (!((UseUse->getOpcode() == ISD::LOAD && 3227 cast<LoadSDNode>(UseUse)->getBasePtr().Val == Use) || 3228 (UseUse->getOpcode() == ISD::STORE) && 3229 cast<StoreSDNode>(UseUse)->getBasePtr().Val == Use)) 3230 RealUse = true; 3231 } 3232 3233 if (!RealUse) { 3234 TryNext = true; 3235 break; 3236 } 3237 } 3238 } 3239 if (TryNext) 3240 continue; 3241 3242 // Check for #2 3243 if (!Op->isPredecessor(N) && !N->isPredecessor(Op)) { 3244 SDOperand Result = isLoad 3245 ? DAG.getIndexedLoad(SDOperand(N,0), BasePtr, Offset, AM) 3246 : DAG.getIndexedStore(SDOperand(N,0), BasePtr, Offset, AM); 3247 ++PostIndexedNodes; 3248 ++NodesCombined; 3249 DOUT << "\nReplacing.5 "; DEBUG(N->dump()); 3250 DOUT << "\nWith: "; DEBUG(Result.Val->dump(&DAG)); 3251 DOUT << '\n'; 3252 std::vector<SDNode*> NowDead; 3253 if (isLoad) { 3254 DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 0), Result.getValue(0), 3255 NowDead); 3256 DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 1), Result.getValue(2), 3257 NowDead); 3258 } else { 3259 DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 0), Result.getValue(1), 3260 NowDead); 3261 } 3262 3263 // Nodes can end up on the worklist more than once. Make sure we do 3264 // not process a node that has been replaced. 3265 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 3266 removeFromWorkList(NowDead[i]); 3267 // Finally, since the node is now dead, remove it from the graph. 3268 DAG.DeleteNode(N); 3269 3270 // Replace the uses of Use with uses of the updated base value. 3271 DAG.ReplaceAllUsesOfValueWith(SDOperand(Op, 0), 3272 Result.getValue(isLoad ? 1 : 0), 3273 NowDead); 3274 removeFromWorkList(Op); 3275 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 3276 removeFromWorkList(NowDead[i]); 3277 DAG.DeleteNode(Op); 3278 3279 return true; 3280 } 3281 } 3282 } 3283 return false; 3284} 3285 3286 3287SDOperand DAGCombiner::visitLOAD(SDNode *N) { 3288 LoadSDNode *LD = cast<LoadSDNode>(N); 3289 SDOperand Chain = LD->getChain(); 3290 SDOperand Ptr = LD->getBasePtr(); 3291 3292 // If there are no uses of the loaded value, change uses of the chain value 3293 // into uses of the chain input (i.e. delete the dead load). 3294 if (N->hasNUsesOfValue(0, 0)) 3295 return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain); 3296 3297 // If this load is directly stored, replace the load value with the stored 3298 // value. 3299 // TODO: Handle store large -> read small portion. 3300 // TODO: Handle TRUNCSTORE/LOADEXT 3301 if (LD->getExtensionType() == ISD::NON_EXTLOAD) { 3302 if (ISD::isNON_TRUNCStore(Chain.Val)) { 3303 StoreSDNode *PrevST = cast<StoreSDNode>(Chain); 3304 if (PrevST->getBasePtr() == Ptr && 3305 PrevST->getValue().getValueType() == N->getValueType(0)) 3306 return CombineTo(N, Chain.getOperand(1), Chain); 3307 } 3308 } 3309 3310 if (CombinerAA) { 3311 // Walk up chain skipping non-aliasing memory nodes. 3312 SDOperand BetterChain = FindBetterChain(N, Chain); 3313 3314 // If there is a better chain. 3315 if (Chain != BetterChain) { 3316 SDOperand ReplLoad; 3317 3318 // Replace the chain to void dependency. 3319 if (LD->getExtensionType() == ISD::NON_EXTLOAD) { 3320 ReplLoad = DAG.getLoad(N->getValueType(0), BetterChain, Ptr, 3321 LD->getSrcValue(), LD->getSrcValueOffset()); 3322 } else { 3323 ReplLoad = DAG.getExtLoad(LD->getExtensionType(), 3324 LD->getValueType(0), 3325 BetterChain, Ptr, LD->getSrcValue(), 3326 LD->getSrcValueOffset(), 3327 LD->getLoadedVT()); 3328 } 3329 3330 // Create token factor to keep old chain connected. 3331 SDOperand Token = DAG.getNode(ISD::TokenFactor, MVT::Other, 3332 Chain, ReplLoad.getValue(1)); 3333 3334 // Replace uses with load result and token factor. Don't add users 3335 // to work list. 3336 return CombineTo(N, ReplLoad.getValue(0), Token, false); 3337 } 3338 } 3339 3340 // Try transforming N to an indexed load. 3341 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) 3342 return SDOperand(N, 0); 3343 3344 return SDOperand(); 3345} 3346 3347SDOperand DAGCombiner::visitSTORE(SDNode *N) { 3348 StoreSDNode *ST = cast<StoreSDNode>(N); 3349 SDOperand Chain = ST->getChain(); 3350 SDOperand Value = ST->getValue(); 3351 SDOperand Ptr = ST->getBasePtr(); 3352 3353 // If this is a store of a bit convert, store the input value. 3354 // FIXME: This needs to know that the resultant store does not need a 3355 // higher alignment than the original. 3356 if (0 && Value.getOpcode() == ISD::BIT_CONVERT) { 3357 return DAG.getStore(Chain, Value.getOperand(0), Ptr, ST->getSrcValue(), 3358 ST->getSrcValueOffset()); 3359 } 3360 3361 // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' 3362 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Value)) { 3363 if (Value.getOpcode() != ISD::TargetConstantFP) { 3364 SDOperand Tmp; 3365 switch (CFP->getValueType(0)) { 3366 default: assert(0 && "Unknown FP type"); 3367 case MVT::f32: 3368 if (!AfterLegalize || TLI.isTypeLegal(MVT::i32)) { 3369 Tmp = DAG.getConstant(FloatToBits(CFP->getValue()), MVT::i32); 3370 return DAG.getStore(Chain, Tmp, Ptr, ST->getSrcValue(), 3371 ST->getSrcValueOffset()); 3372 } 3373 break; 3374 case MVT::f64: 3375 if (!AfterLegalize || TLI.isTypeLegal(MVT::i64)) { 3376 Tmp = DAG.getConstant(DoubleToBits(CFP->getValue()), MVT::i64); 3377 return DAG.getStore(Chain, Tmp, Ptr, ST->getSrcValue(), 3378 ST->getSrcValueOffset()); 3379 } else if (TLI.isTypeLegal(MVT::i32)) { 3380 // Many FP stores are not make apparent until after legalize, e.g. for 3381 // argument passing. Since this is so common, custom legalize the 3382 // 64-bit integer store into two 32-bit stores. 3383 uint64_t Val = DoubleToBits(CFP->getValue()); 3384 SDOperand Lo = DAG.getConstant(Val & 0xFFFFFFFF, MVT::i32); 3385 SDOperand Hi = DAG.getConstant(Val >> 32, MVT::i32); 3386 if (!TLI.isLittleEndian()) std::swap(Lo, Hi); 3387 3388 SDOperand St0 = DAG.getStore(Chain, Lo, Ptr, ST->getSrcValue(), 3389 ST->getSrcValueOffset()); 3390 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr, 3391 DAG.getConstant(4, Ptr.getValueType())); 3392 SDOperand St1 = DAG.getStore(Chain, Hi, Ptr, ST->getSrcValue(), 3393 ST->getSrcValueOffset()+4); 3394 return DAG.getNode(ISD::TokenFactor, MVT::Other, St0, St1); 3395 } 3396 break; 3397 } 3398 } 3399 } 3400 3401 if (CombinerAA) { 3402 // Walk up chain skipping non-aliasing memory nodes. 3403 SDOperand BetterChain = FindBetterChain(N, Chain); 3404 3405 // If there is a better chain. 3406 if (Chain != BetterChain) { 3407 // Replace the chain to avoid dependency. 3408 SDOperand ReplStore; 3409 if (ST->isTruncatingStore()) { 3410 ReplStore = DAG.getTruncStore(BetterChain, Value, Ptr, 3411 ST->getSrcValue(),ST->getSrcValueOffset(), ST->getStoredVT()); 3412 } else { 3413 ReplStore = DAG.getStore(BetterChain, Value, Ptr, 3414 ST->getSrcValue(), ST->getSrcValueOffset()); 3415 } 3416 3417 // Create token to keep both nodes around. 3418 SDOperand Token = 3419 DAG.getNode(ISD::TokenFactor, MVT::Other, Chain, ReplStore); 3420 3421 // Don't add users to work list. 3422 return CombineTo(N, Token, false); 3423 } 3424 } 3425 3426 // Try transforming N to an indexed store. 3427 if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N)) 3428 return SDOperand(N, 0); 3429 3430 return SDOperand(); 3431} 3432 3433SDOperand DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { 3434 SDOperand InVec = N->getOperand(0); 3435 SDOperand InVal = N->getOperand(1); 3436 SDOperand EltNo = N->getOperand(2); 3437 3438 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new 3439 // vector with the inserted element. 3440 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) { 3441 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue(); 3442 SmallVector<SDOperand, 8> Ops(InVec.Val->op_begin(), InVec.Val->op_end()); 3443 if (Elt < Ops.size()) 3444 Ops[Elt] = InVal; 3445 return DAG.getNode(ISD::BUILD_VECTOR, InVec.getValueType(), 3446 &Ops[0], Ops.size()); 3447 } 3448 3449 return SDOperand(); 3450} 3451 3452SDOperand DAGCombiner::visitVINSERT_VECTOR_ELT(SDNode *N) { 3453 SDOperand InVec = N->getOperand(0); 3454 SDOperand InVal = N->getOperand(1); 3455 SDOperand EltNo = N->getOperand(2); 3456 SDOperand NumElts = N->getOperand(3); 3457 SDOperand EltType = N->getOperand(4); 3458 3459 // If the invec is a VBUILD_VECTOR and if EltNo is a constant, build a new 3460 // vector with the inserted element. 3461 if (InVec.getOpcode() == ISD::VBUILD_VECTOR && isa<ConstantSDNode>(EltNo)) { 3462 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue(); 3463 SmallVector<SDOperand, 8> Ops(InVec.Val->op_begin(), InVec.Val->op_end()); 3464 if (Elt < Ops.size()-2) 3465 Ops[Elt] = InVal; 3466 return DAG.getNode(ISD::VBUILD_VECTOR, InVec.getValueType(), 3467 &Ops[0], Ops.size()); 3468 } 3469 3470 return SDOperand(); 3471} 3472 3473SDOperand DAGCombiner::visitVBUILD_VECTOR(SDNode *N) { 3474 unsigned NumInScalars = N->getNumOperands()-2; 3475 SDOperand NumElts = N->getOperand(NumInScalars); 3476 SDOperand EltType = N->getOperand(NumInScalars+1); 3477 3478 // Check to see if this is a VBUILD_VECTOR of a bunch of VEXTRACT_VECTOR_ELT 3479 // operations. If so, and if the EXTRACT_ELT vector inputs come from at most 3480 // two distinct vectors, turn this into a shuffle node. 3481 SDOperand VecIn1, VecIn2; 3482 for (unsigned i = 0; i != NumInScalars; ++i) { 3483 // Ignore undef inputs. 3484 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue; 3485 3486 // If this input is something other than a VEXTRACT_VECTOR_ELT with a 3487 // constant index, bail out. 3488 if (N->getOperand(i).getOpcode() != ISD::VEXTRACT_VECTOR_ELT || 3489 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) { 3490 VecIn1 = VecIn2 = SDOperand(0, 0); 3491 break; 3492 } 3493 3494 // If the input vector type disagrees with the result of the vbuild_vector, 3495 // we can't make a shuffle. 3496 SDOperand ExtractedFromVec = N->getOperand(i).getOperand(0); 3497 if (*(ExtractedFromVec.Val->op_end()-2) != NumElts || 3498 *(ExtractedFromVec.Val->op_end()-1) != EltType) { 3499 VecIn1 = VecIn2 = SDOperand(0, 0); 3500 break; 3501 } 3502 3503 // Otherwise, remember this. We allow up to two distinct input vectors. 3504 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2) 3505 continue; 3506 3507 if (VecIn1.Val == 0) { 3508 VecIn1 = ExtractedFromVec; 3509 } else if (VecIn2.Val == 0) { 3510 VecIn2 = ExtractedFromVec; 3511 } else { 3512 // Too many inputs. 3513 VecIn1 = VecIn2 = SDOperand(0, 0); 3514 break; 3515 } 3516 } 3517 3518 // If everything is good, we can make a shuffle operation. 3519 if (VecIn1.Val) { 3520 SmallVector<SDOperand, 8> BuildVecIndices; 3521 for (unsigned i = 0; i != NumInScalars; ++i) { 3522 if (N->getOperand(i).getOpcode() == ISD::UNDEF) { 3523 BuildVecIndices.push_back(DAG.getNode(ISD::UNDEF, TLI.getPointerTy())); 3524 continue; 3525 } 3526 3527 SDOperand Extract = N->getOperand(i); 3528 3529 // If extracting from the first vector, just use the index directly. 3530 if (Extract.getOperand(0) == VecIn1) { 3531 BuildVecIndices.push_back(Extract.getOperand(1)); 3532 continue; 3533 } 3534 3535 // Otherwise, use InIdx + VecSize 3536 unsigned Idx = cast<ConstantSDNode>(Extract.getOperand(1))->getValue(); 3537 BuildVecIndices.push_back(DAG.getConstant(Idx+NumInScalars, 3538 TLI.getPointerTy())); 3539 } 3540 3541 // Add count and size info. 3542 BuildVecIndices.push_back(NumElts); 3543 BuildVecIndices.push_back(DAG.getValueType(TLI.getPointerTy())); 3544 3545 // Return the new VVECTOR_SHUFFLE node. 3546 SDOperand Ops[5]; 3547 Ops[0] = VecIn1; 3548 if (VecIn2.Val) { 3549 Ops[1] = VecIn2; 3550 } else { 3551 // Use an undef vbuild_vector as input for the second operand. 3552 std::vector<SDOperand> UnOps(NumInScalars, 3553 DAG.getNode(ISD::UNDEF, 3554 cast<VTSDNode>(EltType)->getVT())); 3555 UnOps.push_back(NumElts); 3556 UnOps.push_back(EltType); 3557 Ops[1] = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 3558 &UnOps[0], UnOps.size()); 3559 AddToWorkList(Ops[1].Val); 3560 } 3561 Ops[2] = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 3562 &BuildVecIndices[0], BuildVecIndices.size()); 3563 Ops[3] = NumElts; 3564 Ops[4] = EltType; 3565 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, Ops, 5); 3566 } 3567 3568 return SDOperand(); 3569} 3570 3571SDOperand DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { 3572 SDOperand ShufMask = N->getOperand(2); 3573 unsigned NumElts = ShufMask.getNumOperands(); 3574 3575 // If the shuffle mask is an identity operation on the LHS, return the LHS. 3576 bool isIdentity = true; 3577 for (unsigned i = 0; i != NumElts; ++i) { 3578 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 3579 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) { 3580 isIdentity = false; 3581 break; 3582 } 3583 } 3584 if (isIdentity) return N->getOperand(0); 3585 3586 // If the shuffle mask is an identity operation on the RHS, return the RHS. 3587 isIdentity = true; 3588 for (unsigned i = 0; i != NumElts; ++i) { 3589 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 3590 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) { 3591 isIdentity = false; 3592 break; 3593 } 3594 } 3595 if (isIdentity) return N->getOperand(1); 3596 3597 // Check if the shuffle is a unary shuffle, i.e. one of the vectors is not 3598 // needed at all. 3599 bool isUnary = true; 3600 bool isSplat = true; 3601 int VecNum = -1; 3602 unsigned BaseIdx = 0; 3603 for (unsigned i = 0; i != NumElts; ++i) 3604 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) { 3605 unsigned Idx = cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue(); 3606 int V = (Idx < NumElts) ? 0 : 1; 3607 if (VecNum == -1) { 3608 VecNum = V; 3609 BaseIdx = Idx; 3610 } else { 3611 if (BaseIdx != Idx) 3612 isSplat = false; 3613 if (VecNum != V) { 3614 isUnary = false; 3615 break; 3616 } 3617 } 3618 } 3619 3620 SDOperand N0 = N->getOperand(0); 3621 SDOperand N1 = N->getOperand(1); 3622 // Normalize unary shuffle so the RHS is undef. 3623 if (isUnary && VecNum == 1) 3624 std::swap(N0, N1); 3625 3626 // If it is a splat, check if the argument vector is a build_vector with 3627 // all scalar elements the same. 3628 if (isSplat) { 3629 SDNode *V = N0.Val; 3630 if (V->getOpcode() == ISD::BIT_CONVERT) 3631 V = V->getOperand(0).Val; 3632 if (V->getOpcode() == ISD::BUILD_VECTOR) { 3633 unsigned NumElems = V->getNumOperands()-2; 3634 if (NumElems > BaseIdx) { 3635 SDOperand Base; 3636 bool AllSame = true; 3637 for (unsigned i = 0; i != NumElems; ++i) { 3638 if (V->getOperand(i).getOpcode() != ISD::UNDEF) { 3639 Base = V->getOperand(i); 3640 break; 3641 } 3642 } 3643 // Splat of <u, u, u, u>, return <u, u, u, u> 3644 if (!Base.Val) 3645 return N0; 3646 for (unsigned i = 0; i != NumElems; ++i) { 3647 if (V->getOperand(i).getOpcode() != ISD::UNDEF && 3648 V->getOperand(i) != Base) { 3649 AllSame = false; 3650 break; 3651 } 3652 } 3653 // Splat of <x, x, x, x>, return <x, x, x, x> 3654 if (AllSame) 3655 return N0; 3656 } 3657 } 3658 } 3659 3660 // If it is a unary or the LHS and the RHS are the same node, turn the RHS 3661 // into an undef. 3662 if (isUnary || N0 == N1) { 3663 if (N0.getOpcode() == ISD::UNDEF) 3664 return DAG.getNode(ISD::UNDEF, N->getValueType(0)); 3665 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the 3666 // first operand. 3667 SmallVector<SDOperand, 8> MappedOps; 3668 for (unsigned i = 0, e = ShufMask.getNumOperands(); i != e; ++i) { 3669 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF || 3670 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) { 3671 MappedOps.push_back(ShufMask.getOperand(i)); 3672 } else { 3673 unsigned NewIdx = 3674 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts; 3675 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32)); 3676 } 3677 } 3678 ShufMask = DAG.getNode(ISD::BUILD_VECTOR, ShufMask.getValueType(), 3679 &MappedOps[0], MappedOps.size()); 3680 AddToWorkList(ShufMask.Val); 3681 return DAG.getNode(ISD::VECTOR_SHUFFLE, N->getValueType(0), 3682 N0, 3683 DAG.getNode(ISD::UNDEF, N->getValueType(0)), 3684 ShufMask); 3685 } 3686 3687 return SDOperand(); 3688} 3689 3690SDOperand DAGCombiner::visitVVECTOR_SHUFFLE(SDNode *N) { 3691 SDOperand ShufMask = N->getOperand(2); 3692 unsigned NumElts = ShufMask.getNumOperands()-2; 3693 3694 // If the shuffle mask is an identity operation on the LHS, return the LHS. 3695 bool isIdentity = true; 3696 for (unsigned i = 0; i != NumElts; ++i) { 3697 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 3698 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) { 3699 isIdentity = false; 3700 break; 3701 } 3702 } 3703 if (isIdentity) return N->getOperand(0); 3704 3705 // If the shuffle mask is an identity operation on the RHS, return the RHS. 3706 isIdentity = true; 3707 for (unsigned i = 0; i != NumElts; ++i) { 3708 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 3709 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) { 3710 isIdentity = false; 3711 break; 3712 } 3713 } 3714 if (isIdentity) return N->getOperand(1); 3715 3716 // Check if the shuffle is a unary shuffle, i.e. one of the vectors is not 3717 // needed at all. 3718 bool isUnary = true; 3719 bool isSplat = true; 3720 int VecNum = -1; 3721 unsigned BaseIdx = 0; 3722 for (unsigned i = 0; i != NumElts; ++i) 3723 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) { 3724 unsigned Idx = cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue(); 3725 int V = (Idx < NumElts) ? 0 : 1; 3726 if (VecNum == -1) { 3727 VecNum = V; 3728 BaseIdx = Idx; 3729 } else { 3730 if (BaseIdx != Idx) 3731 isSplat = false; 3732 if (VecNum != V) { 3733 isUnary = false; 3734 break; 3735 } 3736 } 3737 } 3738 3739 SDOperand N0 = N->getOperand(0); 3740 SDOperand N1 = N->getOperand(1); 3741 // Normalize unary shuffle so the RHS is undef. 3742 if (isUnary && VecNum == 1) 3743 std::swap(N0, N1); 3744 3745 // If it is a splat, check if the argument vector is a build_vector with 3746 // all scalar elements the same. 3747 if (isSplat) { 3748 SDNode *V = N0.Val; 3749 3750 // If this is a vbit convert that changes the element type of the vector but 3751 // not the number of vector elements, look through it. Be careful not to 3752 // look though conversions that change things like v4f32 to v2f64. 3753 if (V->getOpcode() == ISD::VBIT_CONVERT) { 3754 SDOperand ConvInput = V->getOperand(0); 3755 if (ConvInput.getValueType() == MVT::Vector && 3756 NumElts == 3757 ConvInput.getConstantOperandVal(ConvInput.getNumOperands()-2)) 3758 V = ConvInput.Val; 3759 } 3760 3761 if (V->getOpcode() == ISD::VBUILD_VECTOR) { 3762 unsigned NumElems = V->getNumOperands()-2; 3763 if (NumElems > BaseIdx) { 3764 SDOperand Base; 3765 bool AllSame = true; 3766 for (unsigned i = 0; i != NumElems; ++i) { 3767 if (V->getOperand(i).getOpcode() != ISD::UNDEF) { 3768 Base = V->getOperand(i); 3769 break; 3770 } 3771 } 3772 // Splat of <u, u, u, u>, return <u, u, u, u> 3773 if (!Base.Val) 3774 return N0; 3775 for (unsigned i = 0; i != NumElems; ++i) { 3776 if (V->getOperand(i).getOpcode() != ISD::UNDEF && 3777 V->getOperand(i) != Base) { 3778 AllSame = false; 3779 break; 3780 } 3781 } 3782 // Splat of <x, x, x, x>, return <x, x, x, x> 3783 if (AllSame) 3784 return N0; 3785 } 3786 } 3787 } 3788 3789 // If it is a unary or the LHS and the RHS are the same node, turn the RHS 3790 // into an undef. 3791 if (isUnary || N0 == N1) { 3792 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the 3793 // first operand. 3794 SmallVector<SDOperand, 8> MappedOps; 3795 for (unsigned i = 0; i != NumElts; ++i) { 3796 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF || 3797 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) { 3798 MappedOps.push_back(ShufMask.getOperand(i)); 3799 } else { 3800 unsigned NewIdx = 3801 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts; 3802 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32)); 3803 } 3804 } 3805 // Add the type/#elts values. 3806 MappedOps.push_back(ShufMask.getOperand(NumElts)); 3807 MappedOps.push_back(ShufMask.getOperand(NumElts+1)); 3808 3809 ShufMask = DAG.getNode(ISD::VBUILD_VECTOR, ShufMask.getValueType(), 3810 &MappedOps[0], MappedOps.size()); 3811 AddToWorkList(ShufMask.Val); 3812 3813 // Build the undef vector. 3814 SDOperand UDVal = DAG.getNode(ISD::UNDEF, MappedOps[0].getValueType()); 3815 for (unsigned i = 0; i != NumElts; ++i) 3816 MappedOps[i] = UDVal; 3817 MappedOps[NumElts ] = *(N0.Val->op_end()-2); 3818 MappedOps[NumElts+1] = *(N0.Val->op_end()-1); 3819 UDVal = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 3820 &MappedOps[0], MappedOps.size()); 3821 3822 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, 3823 N0, UDVal, ShufMask, 3824 MappedOps[NumElts], MappedOps[NumElts+1]); 3825 } 3826 3827 return SDOperand(); 3828} 3829 3830/// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform 3831/// a VAND to a vector_shuffle with the destination vector and a zero vector. 3832/// e.g. VAND V, <0xffffffff, 0, 0xffffffff, 0>. ==> 3833/// vector_shuffle V, Zero, <0, 4, 2, 4> 3834SDOperand DAGCombiner::XformToShuffleWithZero(SDNode *N) { 3835 SDOperand LHS = N->getOperand(0); 3836 SDOperand RHS = N->getOperand(1); 3837 if (N->getOpcode() == ISD::VAND) { 3838 SDOperand DstVecSize = *(LHS.Val->op_end()-2); 3839 SDOperand DstVecEVT = *(LHS.Val->op_end()-1); 3840 if (RHS.getOpcode() == ISD::VBIT_CONVERT) 3841 RHS = RHS.getOperand(0); 3842 if (RHS.getOpcode() == ISD::VBUILD_VECTOR) { 3843 std::vector<SDOperand> IdxOps; 3844 unsigned NumOps = RHS.getNumOperands(); 3845 unsigned NumElts = NumOps-2; 3846 MVT::ValueType EVT = cast<VTSDNode>(RHS.getOperand(NumOps-1))->getVT(); 3847 for (unsigned i = 0; i != NumElts; ++i) { 3848 SDOperand Elt = RHS.getOperand(i); 3849 if (!isa<ConstantSDNode>(Elt)) 3850 return SDOperand(); 3851 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue()) 3852 IdxOps.push_back(DAG.getConstant(i, EVT)); 3853 else if (cast<ConstantSDNode>(Elt)->isNullValue()) 3854 IdxOps.push_back(DAG.getConstant(NumElts, EVT)); 3855 else 3856 return SDOperand(); 3857 } 3858 3859 // Let's see if the target supports this vector_shuffle. 3860 if (!TLI.isVectorClearMaskLegal(IdxOps, EVT, DAG)) 3861 return SDOperand(); 3862 3863 // Return the new VVECTOR_SHUFFLE node. 3864 SDOperand NumEltsNode = DAG.getConstant(NumElts, MVT::i32); 3865 SDOperand EVTNode = DAG.getValueType(EVT); 3866 std::vector<SDOperand> Ops; 3867 LHS = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, LHS, NumEltsNode, 3868 EVTNode); 3869 Ops.push_back(LHS); 3870 AddToWorkList(LHS.Val); 3871 std::vector<SDOperand> ZeroOps(NumElts, DAG.getConstant(0, EVT)); 3872 ZeroOps.push_back(NumEltsNode); 3873 ZeroOps.push_back(EVTNode); 3874 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 3875 &ZeroOps[0], ZeroOps.size())); 3876 IdxOps.push_back(NumEltsNode); 3877 IdxOps.push_back(EVTNode); 3878 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 3879 &IdxOps[0], IdxOps.size())); 3880 Ops.push_back(NumEltsNode); 3881 Ops.push_back(EVTNode); 3882 SDOperand Result = DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, 3883 &Ops[0], Ops.size()); 3884 if (NumEltsNode != DstVecSize || EVTNode != DstVecEVT) { 3885 Result = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, Result, 3886 DstVecSize, DstVecEVT); 3887 } 3888 return Result; 3889 } 3890 } 3891 return SDOperand(); 3892} 3893 3894/// visitVBinOp - Visit a binary vector operation, like VADD. IntOp indicates 3895/// the scalar operation of the vop if it is operating on an integer vector 3896/// (e.g. ADD) and FPOp indicates the FP version (e.g. FADD). 3897SDOperand DAGCombiner::visitVBinOp(SDNode *N, ISD::NodeType IntOp, 3898 ISD::NodeType FPOp) { 3899 MVT::ValueType EltType = cast<VTSDNode>(*(N->op_end()-1))->getVT(); 3900 ISD::NodeType ScalarOp = MVT::isInteger(EltType) ? IntOp : FPOp; 3901 SDOperand LHS = N->getOperand(0); 3902 SDOperand RHS = N->getOperand(1); 3903 SDOperand Shuffle = XformToShuffleWithZero(N); 3904 if (Shuffle.Val) return Shuffle; 3905 3906 // If the LHS and RHS are VBUILD_VECTOR nodes, see if we can constant fold 3907 // this operation. 3908 if (LHS.getOpcode() == ISD::VBUILD_VECTOR && 3909 RHS.getOpcode() == ISD::VBUILD_VECTOR) { 3910 SmallVector<SDOperand, 8> Ops; 3911 for (unsigned i = 0, e = LHS.getNumOperands()-2; i != e; ++i) { 3912 SDOperand LHSOp = LHS.getOperand(i); 3913 SDOperand RHSOp = RHS.getOperand(i); 3914 // If these two elements can't be folded, bail out. 3915 if ((LHSOp.getOpcode() != ISD::UNDEF && 3916 LHSOp.getOpcode() != ISD::Constant && 3917 LHSOp.getOpcode() != ISD::ConstantFP) || 3918 (RHSOp.getOpcode() != ISD::UNDEF && 3919 RHSOp.getOpcode() != ISD::Constant && 3920 RHSOp.getOpcode() != ISD::ConstantFP)) 3921 break; 3922 // Can't fold divide by zero. 3923 if (N->getOpcode() == ISD::VSDIV || N->getOpcode() == ISD::VUDIV) { 3924 if ((RHSOp.getOpcode() == ISD::Constant && 3925 cast<ConstantSDNode>(RHSOp.Val)->isNullValue()) || 3926 (RHSOp.getOpcode() == ISD::ConstantFP && 3927 !cast<ConstantFPSDNode>(RHSOp.Val)->getValue())) 3928 break; 3929 } 3930 Ops.push_back(DAG.getNode(ScalarOp, EltType, LHSOp, RHSOp)); 3931 AddToWorkList(Ops.back().Val); 3932 assert((Ops.back().getOpcode() == ISD::UNDEF || 3933 Ops.back().getOpcode() == ISD::Constant || 3934 Ops.back().getOpcode() == ISD::ConstantFP) && 3935 "Scalar binop didn't fold!"); 3936 } 3937 3938 if (Ops.size() == LHS.getNumOperands()-2) { 3939 Ops.push_back(*(LHS.Val->op_end()-2)); 3940 Ops.push_back(*(LHS.Val->op_end()-1)); 3941 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size()); 3942 } 3943 } 3944 3945 return SDOperand(); 3946} 3947 3948SDOperand DAGCombiner::SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2){ 3949 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!"); 3950 3951 SDOperand SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2, 3952 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 3953 // If we got a simplified select_cc node back from SimplifySelectCC, then 3954 // break it down into a new SETCC node, and a new SELECT node, and then return 3955 // the SELECT node, since we were called with a SELECT node. 3956 if (SCC.Val) { 3957 // Check to see if we got a select_cc back (to turn into setcc/select). 3958 // Otherwise, just return whatever node we got back, like fabs. 3959 if (SCC.getOpcode() == ISD::SELECT_CC) { 3960 SDOperand SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(), 3961 SCC.getOperand(0), SCC.getOperand(1), 3962 SCC.getOperand(4)); 3963 AddToWorkList(SETCC.Val); 3964 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2), 3965 SCC.getOperand(3), SETCC); 3966 } 3967 return SCC; 3968 } 3969 return SDOperand(); 3970} 3971 3972/// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS 3973/// are the two values being selected between, see if we can simplify the 3974/// select. Callers of this should assume that TheSelect is deleted if this 3975/// returns true. As such, they should return the appropriate thing (e.g. the 3976/// node) back to the top-level of the DAG combiner loop to avoid it being 3977/// looked at. 3978/// 3979bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDOperand LHS, 3980 SDOperand RHS) { 3981 3982 // If this is a select from two identical things, try to pull the operation 3983 // through the select. 3984 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){ 3985 // If this is a load and the token chain is identical, replace the select 3986 // of two loads with a load through a select of the address to load from. 3987 // This triggers in things like "select bool X, 10.0, 123.0" after the FP 3988 // constants have been dropped into the constant pool. 3989 if (LHS.getOpcode() == ISD::LOAD && 3990 // Token chains must be identical. 3991 LHS.getOperand(0) == RHS.getOperand(0)) { 3992 LoadSDNode *LLD = cast<LoadSDNode>(LHS); 3993 LoadSDNode *RLD = cast<LoadSDNode>(RHS); 3994 3995 // If this is an EXTLOAD, the VT's must match. 3996 if (LLD->getLoadedVT() == RLD->getLoadedVT()) { 3997 // FIXME: this conflates two src values, discarding one. This is not 3998 // the right thing to do, but nothing uses srcvalues now. When they do, 3999 // turn SrcValue into a list of locations. 4000 SDOperand Addr; 4001 if (TheSelect->getOpcode() == ISD::SELECT) { 4002 // Check that the condition doesn't reach either load. If so, folding 4003 // this will induce a cycle into the DAG. 4004 if (!LLD->isPredecessor(TheSelect->getOperand(0).Val) && 4005 !RLD->isPredecessor(TheSelect->getOperand(0).Val)) { 4006 Addr = DAG.getNode(ISD::SELECT, LLD->getBasePtr().getValueType(), 4007 TheSelect->getOperand(0), LLD->getBasePtr(), 4008 RLD->getBasePtr()); 4009 } 4010 } else { 4011 // Check that the condition doesn't reach either load. If so, folding 4012 // this will induce a cycle into the DAG. 4013 if (!LLD->isPredecessor(TheSelect->getOperand(0).Val) && 4014 !RLD->isPredecessor(TheSelect->getOperand(0).Val) && 4015 !LLD->isPredecessor(TheSelect->getOperand(1).Val) && 4016 !RLD->isPredecessor(TheSelect->getOperand(1).Val)) { 4017 Addr = DAG.getNode(ISD::SELECT_CC, LLD->getBasePtr().getValueType(), 4018 TheSelect->getOperand(0), 4019 TheSelect->getOperand(1), 4020 LLD->getBasePtr(), RLD->getBasePtr(), 4021 TheSelect->getOperand(4)); 4022 } 4023 } 4024 4025 if (Addr.Val) { 4026 SDOperand Load; 4027 if (LLD->getExtensionType() == ISD::NON_EXTLOAD) 4028 Load = DAG.getLoad(TheSelect->getValueType(0), LLD->getChain(), 4029 Addr,LLD->getSrcValue(), 4030 LLD->getSrcValueOffset()); 4031 else { 4032 Load = DAG.getExtLoad(LLD->getExtensionType(), 4033 TheSelect->getValueType(0), 4034 LLD->getChain(), Addr, LLD->getSrcValue(), 4035 LLD->getSrcValueOffset(), 4036 LLD->getLoadedVT()); 4037 } 4038 // Users of the select now use the result of the load. 4039 CombineTo(TheSelect, Load); 4040 4041 // Users of the old loads now use the new load's chain. We know the 4042 // old-load value is dead now. 4043 CombineTo(LHS.Val, Load.getValue(0), Load.getValue(1)); 4044 CombineTo(RHS.Val, Load.getValue(0), Load.getValue(1)); 4045 return true; 4046 } 4047 } 4048 } 4049 } 4050 4051 return false; 4052} 4053 4054SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1, 4055 SDOperand N2, SDOperand N3, 4056 ISD::CondCode CC, bool NotExtCompare) { 4057 4058 MVT::ValueType VT = N2.getValueType(); 4059 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 4060 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val); 4061 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val); 4062 4063 // Determine if the condition we're dealing with is constant 4064 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false); 4065 if (SCC.Val) AddToWorkList(SCC.Val); 4066 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val); 4067 4068 // fold select_cc true, x, y -> x 4069 if (SCCC && SCCC->getValue()) 4070 return N2; 4071 // fold select_cc false, x, y -> y 4072 if (SCCC && SCCC->getValue() == 0) 4073 return N3; 4074 4075 // Check to see if we can simplify the select into an fabs node 4076 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) { 4077 // Allow either -0.0 or 0.0 4078 if (CFP->getValue() == 0.0) { 4079 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs 4080 if ((CC == ISD::SETGE || CC == ISD::SETGT) && 4081 N0 == N2 && N3.getOpcode() == ISD::FNEG && 4082 N2 == N3.getOperand(0)) 4083 return DAG.getNode(ISD::FABS, VT, N0); 4084 4085 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs 4086 if ((CC == ISD::SETLT || CC == ISD::SETLE) && 4087 N0 == N3 && N2.getOpcode() == ISD::FNEG && 4088 N2.getOperand(0) == N3) 4089 return DAG.getNode(ISD::FABS, VT, N3); 4090 } 4091 } 4092 4093 // Check to see if we can perform the "gzip trick", transforming 4094 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A 4095 if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT && 4096 MVT::isInteger(N0.getValueType()) && 4097 MVT::isInteger(N2.getValueType()) && 4098 (N1C->isNullValue() || // (a < 0) ? b : 0 4099 (N1C->getValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0 4100 MVT::ValueType XType = N0.getValueType(); 4101 MVT::ValueType AType = N2.getValueType(); 4102 if (XType >= AType) { 4103 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a 4104 // single-bit constant. 4105 if (N2C && ((N2C->getValue() & (N2C->getValue()-1)) == 0)) { 4106 unsigned ShCtV = Log2_64(N2C->getValue()); 4107 ShCtV = MVT::getSizeInBits(XType)-ShCtV-1; 4108 SDOperand ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy()); 4109 SDOperand Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt); 4110 AddToWorkList(Shift.Val); 4111 if (XType > AType) { 4112 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift); 4113 AddToWorkList(Shift.Val); 4114 } 4115 return DAG.getNode(ISD::AND, AType, Shift, N2); 4116 } 4117 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0, 4118 DAG.getConstant(MVT::getSizeInBits(XType)-1, 4119 TLI.getShiftAmountTy())); 4120 AddToWorkList(Shift.Val); 4121 if (XType > AType) { 4122 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift); 4123 AddToWorkList(Shift.Val); 4124 } 4125 return DAG.getNode(ISD::AND, AType, Shift, N2); 4126 } 4127 } 4128 4129 // fold select C, 16, 0 -> shl C, 4 4130 if (N2C && N3C && N3C->isNullValue() && isPowerOf2_64(N2C->getValue()) && 4131 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) { 4132 4133 // If the caller doesn't want us to simplify this into a zext of a compare, 4134 // don't do it. 4135 if (NotExtCompare && N2C->getValue() == 1) 4136 return SDOperand(); 4137 4138 // Get a SetCC of the condition 4139 // FIXME: Should probably make sure that setcc is legal if we ever have a 4140 // target where it isn't. 4141 SDOperand Temp, SCC; 4142 // cast from setcc result type to select result type 4143 if (AfterLegalize) { 4144 SCC = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC); 4145 if (N2.getValueType() < SCC.getValueType()) 4146 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType()); 4147 else 4148 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC); 4149 } else { 4150 SCC = DAG.getSetCC(MVT::i1, N0, N1, CC); 4151 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC); 4152 } 4153 AddToWorkList(SCC.Val); 4154 AddToWorkList(Temp.Val); 4155 4156 if (N2C->getValue() == 1) 4157 return Temp; 4158 // shl setcc result by log2 n2c 4159 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp, 4160 DAG.getConstant(Log2_64(N2C->getValue()), 4161 TLI.getShiftAmountTy())); 4162 } 4163 4164 // Check to see if this is the equivalent of setcc 4165 // FIXME: Turn all of these into setcc if setcc if setcc is legal 4166 // otherwise, go ahead with the folds. 4167 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getValue() == 1ULL)) { 4168 MVT::ValueType XType = N0.getValueType(); 4169 if (TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultTy())) { 4170 SDOperand Res = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC); 4171 if (Res.getValueType() != VT) 4172 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res); 4173 return Res; 4174 } 4175 4176 // seteq X, 0 -> srl (ctlz X, log2(size(X))) 4177 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ && 4178 TLI.isOperationLegal(ISD::CTLZ, XType)) { 4179 SDOperand Ctlz = DAG.getNode(ISD::CTLZ, XType, N0); 4180 return DAG.getNode(ISD::SRL, XType, Ctlz, 4181 DAG.getConstant(Log2_32(MVT::getSizeInBits(XType)), 4182 TLI.getShiftAmountTy())); 4183 } 4184 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1) 4185 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) { 4186 SDOperand NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType), 4187 N0); 4188 SDOperand NotN0 = DAG.getNode(ISD::XOR, XType, N0, 4189 DAG.getConstant(~0ULL, XType)); 4190 return DAG.getNode(ISD::SRL, XType, 4191 DAG.getNode(ISD::AND, XType, NegN0, NotN0), 4192 DAG.getConstant(MVT::getSizeInBits(XType)-1, 4193 TLI.getShiftAmountTy())); 4194 } 4195 // setgt X, -1 -> xor (srl (X, size(X)-1), 1) 4196 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) { 4197 SDOperand Sign = DAG.getNode(ISD::SRL, XType, N0, 4198 DAG.getConstant(MVT::getSizeInBits(XType)-1, 4199 TLI.getShiftAmountTy())); 4200 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType)); 4201 } 4202 } 4203 4204 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X -> 4205 // Y = sra (X, size(X)-1); xor (add (X, Y), Y) 4206 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) && 4207 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1) && 4208 N2.getOperand(0) == N1 && MVT::isInteger(N0.getValueType())) { 4209 MVT::ValueType XType = N0.getValueType(); 4210 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0, 4211 DAG.getConstant(MVT::getSizeInBits(XType)-1, 4212 TLI.getShiftAmountTy())); 4213 SDOperand Add = DAG.getNode(ISD::ADD, XType, N0, Shift); 4214 AddToWorkList(Shift.Val); 4215 AddToWorkList(Add.Val); 4216 return DAG.getNode(ISD::XOR, XType, Add, Shift); 4217 } 4218 // Check to see if this is an integer abs. select_cc setgt X, -1, X, -X -> 4219 // Y = sra (X, size(X)-1); xor (add (X, Y), Y) 4220 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT && 4221 N0 == N2 && N3.getOpcode() == ISD::SUB && N0 == N3.getOperand(1)) { 4222 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N3.getOperand(0))) { 4223 MVT::ValueType XType = N0.getValueType(); 4224 if (SubC->isNullValue() && MVT::isInteger(XType)) { 4225 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0, 4226 DAG.getConstant(MVT::getSizeInBits(XType)-1, 4227 TLI.getShiftAmountTy())); 4228 SDOperand Add = DAG.getNode(ISD::ADD, XType, N0, Shift); 4229 AddToWorkList(Shift.Val); 4230 AddToWorkList(Add.Val); 4231 return DAG.getNode(ISD::XOR, XType, Add, Shift); 4232 } 4233 } 4234 } 4235 4236 return SDOperand(); 4237} 4238 4239/// SimplifySetCC - This is a stub for TargetLowering::SimplifySetCC. 4240SDOperand DAGCombiner::SimplifySetCC(MVT::ValueType VT, SDOperand N0, 4241 SDOperand N1, ISD::CondCode Cond, 4242 bool foldBooleans) { 4243 TargetLowering::DAGCombinerInfo 4244 DagCombineInfo(DAG, !AfterLegalize, false, this); 4245 return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo); 4246} 4247 4248/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant, 4249/// return a DAG expression to select that will generate the same value by 4250/// multiplying by a magic number. See: 4251/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 4252SDOperand DAGCombiner::BuildSDIV(SDNode *N) { 4253 std::vector<SDNode*> Built; 4254 SDOperand S = TLI.BuildSDIV(N, DAG, &Built); 4255 4256 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 4257 ii != ee; ++ii) 4258 AddToWorkList(*ii); 4259 return S; 4260} 4261 4262/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant, 4263/// return a DAG expression to select that will generate the same value by 4264/// multiplying by a magic number. See: 4265/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 4266SDOperand DAGCombiner::BuildUDIV(SDNode *N) { 4267 std::vector<SDNode*> Built; 4268 SDOperand S = TLI.BuildUDIV(N, DAG, &Built); 4269 4270 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 4271 ii != ee; ++ii) 4272 AddToWorkList(*ii); 4273 return S; 4274} 4275 4276/// FindBaseOffset - Return true if base is known not to alias with anything 4277/// but itself. Provides base object and offset as results. 4278static bool FindBaseOffset(SDOperand Ptr, SDOperand &Base, int64_t &Offset) { 4279 // Assume it is a primitive operation. 4280 Base = Ptr; Offset = 0; 4281 4282 // If it's an adding a simple constant then integrate the offset. 4283 if (Base.getOpcode() == ISD::ADD) { 4284 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) { 4285 Base = Base.getOperand(0); 4286 Offset += C->getValue(); 4287 } 4288 } 4289 4290 // If it's any of the following then it can't alias with anything but itself. 4291 return isa<FrameIndexSDNode>(Base) || 4292 isa<ConstantPoolSDNode>(Base) || 4293 isa<GlobalAddressSDNode>(Base); 4294} 4295 4296/// isAlias - Return true if there is any possibility that the two addresses 4297/// overlap. 4298bool DAGCombiner::isAlias(SDOperand Ptr1, int64_t Size1, 4299 const Value *SrcValue1, int SrcValueOffset1, 4300 SDOperand Ptr2, int64_t Size2, 4301 const Value *SrcValue2, int SrcValueOffset2) 4302{ 4303 // If they are the same then they must be aliases. 4304 if (Ptr1 == Ptr2) return true; 4305 4306 // Gather base node and offset information. 4307 SDOperand Base1, Base2; 4308 int64_t Offset1, Offset2; 4309 bool KnownBase1 = FindBaseOffset(Ptr1, Base1, Offset1); 4310 bool KnownBase2 = FindBaseOffset(Ptr2, Base2, Offset2); 4311 4312 // If they have a same base address then... 4313 if (Base1 == Base2) { 4314 // Check to see if the addresses overlap. 4315 return!((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1); 4316 } 4317 4318 // If we know both bases then they can't alias. 4319 if (KnownBase1 && KnownBase2) return false; 4320 4321 if (CombinerGlobalAA) { 4322 // Use alias analysis information. 4323 int Overlap1 = Size1 + SrcValueOffset1 + Offset1; 4324 int Overlap2 = Size2 + SrcValueOffset2 + Offset2; 4325 AliasAnalysis::AliasResult AAResult = 4326 AA.alias(SrcValue1, Overlap1, SrcValue2, Overlap2); 4327 if (AAResult == AliasAnalysis::NoAlias) 4328 return false; 4329 } 4330 4331 // Otherwise we have to assume they alias. 4332 return true; 4333} 4334 4335/// FindAliasInfo - Extracts the relevant alias information from the memory 4336/// node. Returns true if the operand was a load. 4337bool DAGCombiner::FindAliasInfo(SDNode *N, 4338 SDOperand &Ptr, int64_t &Size, 4339 const Value *&SrcValue, int &SrcValueOffset) { 4340 if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) { 4341 Ptr = LD->getBasePtr(); 4342 Size = MVT::getSizeInBits(LD->getLoadedVT()) >> 3; 4343 SrcValue = LD->getSrcValue(); 4344 SrcValueOffset = LD->getSrcValueOffset(); 4345 return true; 4346 } else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) { 4347 Ptr = ST->getBasePtr(); 4348 Size = MVT::getSizeInBits(ST->getStoredVT()) >> 3; 4349 SrcValue = ST->getSrcValue(); 4350 SrcValueOffset = ST->getSrcValueOffset(); 4351 } else { 4352 assert(0 && "FindAliasInfo expected a memory operand"); 4353 } 4354 4355 return false; 4356} 4357 4358/// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes, 4359/// looking for aliasing nodes and adding them to the Aliases vector. 4360void DAGCombiner::GatherAllAliases(SDNode *N, SDOperand OriginalChain, 4361 SmallVector<SDOperand, 8> &Aliases) { 4362 SmallVector<SDOperand, 8> Chains; // List of chains to visit. 4363 std::set<SDNode *> Visited; // Visited node set. 4364 4365 // Get alias information for node. 4366 SDOperand Ptr; 4367 int64_t Size; 4368 const Value *SrcValue; 4369 int SrcValueOffset; 4370 bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset); 4371 4372 // Starting off. 4373 Chains.push_back(OriginalChain); 4374 4375 // Look at each chain and determine if it is an alias. If so, add it to the 4376 // aliases list. If not, then continue up the chain looking for the next 4377 // candidate. 4378 while (!Chains.empty()) { 4379 SDOperand Chain = Chains.back(); 4380 Chains.pop_back(); 4381 4382 // Don't bother if we've been before. 4383 if (Visited.find(Chain.Val) != Visited.end()) continue; 4384 Visited.insert(Chain.Val); 4385 4386 switch (Chain.getOpcode()) { 4387 case ISD::EntryToken: 4388 // Entry token is ideal chain operand, but handled in FindBetterChain. 4389 break; 4390 4391 case ISD::LOAD: 4392 case ISD::STORE: { 4393 // Get alias information for Chain. 4394 SDOperand OpPtr; 4395 int64_t OpSize; 4396 const Value *OpSrcValue; 4397 int OpSrcValueOffset; 4398 bool IsOpLoad = FindAliasInfo(Chain.Val, OpPtr, OpSize, 4399 OpSrcValue, OpSrcValueOffset); 4400 4401 // If chain is alias then stop here. 4402 if (!(IsLoad && IsOpLoad) && 4403 isAlias(Ptr, Size, SrcValue, SrcValueOffset, 4404 OpPtr, OpSize, OpSrcValue, OpSrcValueOffset)) { 4405 Aliases.push_back(Chain); 4406 } else { 4407 // Look further up the chain. 4408 Chains.push_back(Chain.getOperand(0)); 4409 // Clean up old chain. 4410 AddToWorkList(Chain.Val); 4411 } 4412 break; 4413 } 4414 4415 case ISD::TokenFactor: 4416 // We have to check each of the operands of the token factor, so we queue 4417 // then up. Adding the operands to the queue (stack) in reverse order 4418 // maintains the original order and increases the likelihood that getNode 4419 // will find a matching token factor (CSE.) 4420 for (unsigned n = Chain.getNumOperands(); n;) 4421 Chains.push_back(Chain.getOperand(--n)); 4422 // Eliminate the token factor if we can. 4423 AddToWorkList(Chain.Val); 4424 break; 4425 4426 default: 4427 // For all other instructions we will just have to take what we can get. 4428 Aliases.push_back(Chain); 4429 break; 4430 } 4431 } 4432} 4433 4434/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking 4435/// for a better chain (aliasing node.) 4436SDOperand DAGCombiner::FindBetterChain(SDNode *N, SDOperand OldChain) { 4437 SmallVector<SDOperand, 8> Aliases; // Ops for replacing token factor. 4438 4439 // Accumulate all the aliases to this node. 4440 GatherAllAliases(N, OldChain, Aliases); 4441 4442 if (Aliases.size() == 0) { 4443 // If no operands then chain to entry token. 4444 return DAG.getEntryNode(); 4445 } else if (Aliases.size() == 1) { 4446 // If a single operand then chain to it. We don't need to revisit it. 4447 return Aliases[0]; 4448 } 4449 4450 // Construct a custom tailored token factor. 4451 SDOperand NewChain = DAG.getNode(ISD::TokenFactor, MVT::Other, 4452 &Aliases[0], Aliases.size()); 4453 4454 // Make sure the old chain gets cleaned up. 4455 if (NewChain != OldChain) AddToWorkList(OldChain.Val); 4456 4457 return NewChain; 4458} 4459 4460// SelectionDAG::Combine - This is the entry point for the file. 4461// 4462void SelectionDAG::Combine(bool RunningAfterLegalize, AliasAnalysis &AA) { 4463 if (!RunningAfterLegalize && ViewDAGCombine1) 4464 viewGraph(); 4465 if (RunningAfterLegalize && ViewDAGCombine2) 4466 viewGraph(); 4467 /// run - This is the main entry point to this class. 4468 /// 4469 DAGCombiner(*this, AA).Run(RunningAfterLegalize); 4470} 4471