DAGCombiner.cpp revision 279f053eae35729f449f38e08618664b118806bd
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/CodeGen/SelectionDAG.h" 34#include "llvm/Support/Debug.h" 35#include "llvm/Support/MathExtras.h" 36#include "llvm/Target/TargetLowering.h" 37#include "llvm/Support/Compiler.h" 38#include "llvm/Support/CommandLine.h" 39#include <algorithm> 40#include <cmath> 41#include <iostream> 42#include <algorithm> 43using namespace llvm; 44 45namespace { 46 static Statistic<> NodesCombined ("dagcombiner", 47 "Number of dag nodes combined"); 48 49 50static cl::opt<bool> 51 CombinerAA("combiner-alias-analysis", cl::Hidden, 52 cl::desc("Turn on alias analysis turning testing")); 53 54class VISIBILITY_HIDDEN DAGCombiner { 55 SelectionDAG &DAG; 56 TargetLowering &TLI; 57 bool AfterLegalize; 58 59 // Worklist of all of the nodes that need to be simplified. 60 std::vector<SDNode*> WorkList; 61 62 /// AddUsersToWorkList - When an instruction is simplified, add all users of 63 /// the instruction to the work lists because they might get more simplified 64 /// now. 65 /// 66 void AddUsersToWorkList(SDNode *N) { 67 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 68 UI != UE; ++UI) 69 WorkList.push_back(*UI); 70 } 71 72 /// removeFromWorkList - remove all instances of N from the worklist. 73 /// 74 void removeFromWorkList(SDNode *N) { 75 WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N), 76 WorkList.end()); 77 } 78 79 public: 80 void AddToWorkList(SDNode *N) { 81 WorkList.push_back(N); 82 } 83 84 SDOperand CombineTo(SDNode *N, const SDOperand *To, unsigned NumTo) { 85 assert(N->getNumValues() == NumTo && "Broken CombineTo call!"); 86 ++NodesCombined; 87 DEBUG(std::cerr << "\nReplacing "; N->dump(); 88 std::cerr << "\nWith: "; To[0].Val->dump(&DAG); 89 std::cerr << " and " << NumTo-1 << " other values\n"); 90 std::vector<SDNode*> NowDead; 91 DAG.ReplaceAllUsesWith(N, To, &NowDead); 92 93 // Push the new nodes and any users onto the worklist 94 for (unsigned i = 0, e = NumTo; i != e; ++i) { 95 WorkList.push_back(To[i].Val); 96 AddUsersToWorkList(To[i].Val); 97 } 98 99 // Nodes can end up on the worklist more than once. Make sure we do 100 // not process a node that has been replaced. 101 removeFromWorkList(N); 102 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 103 removeFromWorkList(NowDead[i]); 104 105 // Finally, since the node is now dead, remove it from the graph. 106 DAG.DeleteNode(N); 107 return SDOperand(N, 0); 108 } 109 110 SDOperand CombineTo(SDNode *N, SDOperand Res) { 111 return CombineTo(N, &Res, 1); 112 } 113 114 SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) { 115 SDOperand To[] = { Res0, Res1 }; 116 return CombineTo(N, To, 2); 117 } 118 private: 119 120 /// SimplifyDemandedBits - Check the specified integer node value to see if 121 /// it can be simplified or if things it uses can be simplified by bit 122 /// propagation. If so, return true. 123 bool SimplifyDemandedBits(SDOperand Op) { 124 TargetLowering::TargetLoweringOpt TLO(DAG); 125 uint64_t KnownZero, KnownOne; 126 uint64_t Demanded = MVT::getIntVTBitMask(Op.getValueType()); 127 if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO)) 128 return false; 129 130 // Revisit the node. 131 WorkList.push_back(Op.Val); 132 133 // Replace the old value with the new one. 134 ++NodesCombined; 135 DEBUG(std::cerr << "\nReplacing "; TLO.Old.Val->dump(); 136 std::cerr << "\nWith: "; TLO.New.Val->dump(&DAG); 137 std::cerr << '\n'); 138 139 std::vector<SDNode*> NowDead; 140 DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, NowDead); 141 142 // Push the new node and any (possibly new) users onto the worklist. 143 WorkList.push_back(TLO.New.Val); 144 AddUsersToWorkList(TLO.New.Val); 145 146 // Nodes can end up on the worklist more than once. Make sure we do 147 // not process a node that has been replaced. 148 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 149 removeFromWorkList(NowDead[i]); 150 151 // Finally, if the node is now dead, remove it from the graph. The node 152 // may not be dead if the replacement process recursively simplified to 153 // something else needing this node. 154 if (TLO.Old.Val->use_empty()) { 155 removeFromWorkList(TLO.Old.Val); 156 DAG.DeleteNode(TLO.Old.Val); 157 } 158 return true; 159 } 160 161 /// visit - call the node-specific routine that knows how to fold each 162 /// particular type of node. 163 SDOperand visit(SDNode *N); 164 165 // Visitation implementation - Implement dag node combining for different 166 // node types. The semantics are as follows: 167 // Return Value: 168 // SDOperand.Val == 0 - No change was made 169 // SDOperand.Val == N - N was replaced, is dead, and is already handled. 170 // otherwise - N should be replaced by the returned Operand. 171 // 172 SDOperand visitTokenFactor(SDNode *N); 173 SDOperand visitADD(SDNode *N); 174 SDOperand visitSUB(SDNode *N); 175 SDOperand visitMUL(SDNode *N); 176 SDOperand visitSDIV(SDNode *N); 177 SDOperand visitUDIV(SDNode *N); 178 SDOperand visitSREM(SDNode *N); 179 SDOperand visitUREM(SDNode *N); 180 SDOperand visitMULHU(SDNode *N); 181 SDOperand visitMULHS(SDNode *N); 182 SDOperand visitAND(SDNode *N); 183 SDOperand visitOR(SDNode *N); 184 SDOperand visitXOR(SDNode *N); 185 SDOperand visitVBinOp(SDNode *N, ISD::NodeType IntOp, ISD::NodeType FPOp); 186 SDOperand visitSHL(SDNode *N); 187 SDOperand visitSRA(SDNode *N); 188 SDOperand visitSRL(SDNode *N); 189 SDOperand visitCTLZ(SDNode *N); 190 SDOperand visitCTTZ(SDNode *N); 191 SDOperand visitCTPOP(SDNode *N); 192 SDOperand visitSELECT(SDNode *N); 193 SDOperand visitSELECT_CC(SDNode *N); 194 SDOperand visitSETCC(SDNode *N); 195 SDOperand visitSIGN_EXTEND(SDNode *N); 196 SDOperand visitZERO_EXTEND(SDNode *N); 197 SDOperand visitANY_EXTEND(SDNode *N); 198 SDOperand visitSIGN_EXTEND_INREG(SDNode *N); 199 SDOperand visitTRUNCATE(SDNode *N); 200 SDOperand visitBIT_CONVERT(SDNode *N); 201 SDOperand visitVBIT_CONVERT(SDNode *N); 202 SDOperand visitFADD(SDNode *N); 203 SDOperand visitFSUB(SDNode *N); 204 SDOperand visitFMUL(SDNode *N); 205 SDOperand visitFDIV(SDNode *N); 206 SDOperand visitFREM(SDNode *N); 207 SDOperand visitFCOPYSIGN(SDNode *N); 208 SDOperand visitSINT_TO_FP(SDNode *N); 209 SDOperand visitUINT_TO_FP(SDNode *N); 210 SDOperand visitFP_TO_SINT(SDNode *N); 211 SDOperand visitFP_TO_UINT(SDNode *N); 212 SDOperand visitFP_ROUND(SDNode *N); 213 SDOperand visitFP_ROUND_INREG(SDNode *N); 214 SDOperand visitFP_EXTEND(SDNode *N); 215 SDOperand visitFNEG(SDNode *N); 216 SDOperand visitFABS(SDNode *N); 217 SDOperand visitBRCOND(SDNode *N); 218 SDOperand visitBR_CC(SDNode *N); 219 SDOperand visitLOAD(SDNode *N); 220 SDOperand visitXEXTLOAD(SDNode *N); 221 SDOperand visitSTORE(SDNode *N); 222 SDOperand visitINSERT_VECTOR_ELT(SDNode *N); 223 SDOperand visitVINSERT_VECTOR_ELT(SDNode *N); 224 SDOperand visitVBUILD_VECTOR(SDNode *N); 225 SDOperand visitVECTOR_SHUFFLE(SDNode *N); 226 SDOperand visitVVECTOR_SHUFFLE(SDNode *N); 227 228 SDOperand XformToShuffleWithZero(SDNode *N); 229 SDOperand ReassociateOps(unsigned Opc, SDOperand LHS, SDOperand RHS); 230 231 bool SimplifySelectOps(SDNode *SELECT, SDOperand LHS, SDOperand RHS); 232 SDOperand SimplifyBinOpWithSameOpcodeHands(SDNode *N); 233 SDOperand SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2); 234 SDOperand SimplifySelectCC(SDOperand N0, SDOperand N1, SDOperand N2, 235 SDOperand N3, ISD::CondCode CC); 236 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1, 237 ISD::CondCode Cond, bool foldBooleans = true); 238 SDOperand ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *, MVT::ValueType); 239 SDOperand BuildSDIV(SDNode *N); 240 SDOperand BuildUDIV(SDNode *N); 241 SDNode *MatchRotate(SDOperand LHS, SDOperand RHS); 242 243 /// FindBaseOffset - Return true if we can determine base and offset 244 /// information from a given pointer operand. Provides base and offset as a 245 /// result. 246 static bool FindBaseOffset(SDOperand Ptr, 247 SDOperand &Object, int64_t &Offset); 248 249 /// isAlias - Return true if there is the possibility that the two addresses 250 /// overlap. 251 static bool isAlias(SDOperand Ptr1, int64_t Size1, SDOperand SrcValue1, 252 SDOperand Ptr2, int64_t Size2, SDOperand SrcValue2); 253 254 /// FindAliasInfo - Extracts the relevant alias information from the memory 255 /// node. 256 static void FindAliasInfo(SDNode *N, 257 SDOperand &Ptr, int64_t &Size, SDOperand &SrcValue); 258 259 /// hasChain - Return true if Op has a chain. Provides chain if present. 260 /// 261 static bool hasChain(SDOperand Op, SDOperand &Chain); 262 263 /// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, 264 /// looking for a better chain. 265 SDOperand FindBetterChain(SDNode *N, SDOperand Chain); 266 267public: 268 DAGCombiner(SelectionDAG &D) 269 : DAG(D), TLI(D.getTargetLoweringInfo()), AfterLegalize(false) {} 270 271 /// Run - runs the dag combiner on all nodes in the work list 272 void Run(bool RunningAfterLegalize); 273 }; 274} 275 276//===----------------------------------------------------------------------===// 277// TargetLowering::DAGCombinerInfo implementation 278//===----------------------------------------------------------------------===// 279 280void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) { 281 ((DAGCombiner*)DC)->AddToWorkList(N); 282} 283 284SDOperand TargetLowering::DAGCombinerInfo:: 285CombineTo(SDNode *N, const std::vector<SDOperand> &To) { 286 return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size()); 287} 288 289SDOperand TargetLowering::DAGCombinerInfo:: 290CombineTo(SDNode *N, SDOperand Res) { 291 return ((DAGCombiner*)DC)->CombineTo(N, Res); 292} 293 294 295SDOperand TargetLowering::DAGCombinerInfo:: 296CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1) { 297 return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1); 298} 299 300 301 302 303//===----------------------------------------------------------------------===// 304 305 306// isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc 307// that selects between the values 1 and 0, making it equivalent to a setcc. 308// Also, set the incoming LHS, RHS, and CC references to the appropriate 309// nodes based on the type of node we are checking. This simplifies life a 310// bit for the callers. 311static bool isSetCCEquivalent(SDOperand N, SDOperand &LHS, SDOperand &RHS, 312 SDOperand &CC) { 313 if (N.getOpcode() == ISD::SETCC) { 314 LHS = N.getOperand(0); 315 RHS = N.getOperand(1); 316 CC = N.getOperand(2); 317 return true; 318 } 319 if (N.getOpcode() == ISD::SELECT_CC && 320 N.getOperand(2).getOpcode() == ISD::Constant && 321 N.getOperand(3).getOpcode() == ISD::Constant && 322 cast<ConstantSDNode>(N.getOperand(2))->getValue() == 1 && 323 cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) { 324 LHS = N.getOperand(0); 325 RHS = N.getOperand(1); 326 CC = N.getOperand(4); 327 return true; 328 } 329 return false; 330} 331 332// isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only 333// one use. If this is true, it allows the users to invert the operation for 334// free when it is profitable to do so. 335static bool isOneUseSetCC(SDOperand N) { 336 SDOperand N0, N1, N2; 337 if (isSetCCEquivalent(N, N0, N1, N2) && N.Val->hasOneUse()) 338 return true; 339 return false; 340} 341 342SDOperand DAGCombiner::ReassociateOps(unsigned Opc, SDOperand N0, SDOperand N1){ 343 MVT::ValueType VT = N0.getValueType(); 344 // reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use 345 // reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2)) 346 if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) { 347 if (isa<ConstantSDNode>(N1)) { 348 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(1), N1); 349 AddToWorkList(OpNode.Val); 350 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(0)); 351 } else if (N0.hasOneUse()) { 352 SDOperand OpNode = DAG.getNode(Opc, VT, N0.getOperand(0), N1); 353 AddToWorkList(OpNode.Val); 354 return DAG.getNode(Opc, VT, OpNode, N0.getOperand(1)); 355 } 356 } 357 // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use 358 // reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2)) 359 if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) { 360 if (isa<ConstantSDNode>(N0)) { 361 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(1), N0); 362 AddToWorkList(OpNode.Val); 363 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(0)); 364 } else if (N1.hasOneUse()) { 365 SDOperand OpNode = DAG.getNode(Opc, VT, N1.getOperand(0), N0); 366 AddToWorkList(OpNode.Val); 367 return DAG.getNode(Opc, VT, OpNode, N1.getOperand(1)); 368 } 369 } 370 return SDOperand(); 371} 372 373void DAGCombiner::Run(bool RunningAfterLegalize) { 374 // set the instance variable, so that the various visit routines may use it. 375 AfterLegalize = RunningAfterLegalize; 376 377 // Add all the dag nodes to the worklist. 378 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 379 E = DAG.allnodes_end(); I != E; ++I) 380 WorkList.push_back(I); 381 382 // Create a dummy node (which is not added to allnodes), that adds a reference 383 // to the root node, preventing it from being deleted, and tracking any 384 // changes of the root. 385 HandleSDNode Dummy(DAG.getRoot()); 386 387 388 /// DagCombineInfo - Expose the DAG combiner to the target combiner impls. 389 TargetLowering::DAGCombinerInfo 390 DagCombineInfo(DAG, !RunningAfterLegalize, this); 391 392 // while the worklist isn't empty, inspect the node on the end of it and 393 // try and combine it. 394 while (!WorkList.empty()) { 395 SDNode *N = WorkList.back(); 396 WorkList.pop_back(); 397 398 // If N has no uses, it is dead. Make sure to revisit all N's operands once 399 // N is deleted from the DAG, since they too may now be dead or may have a 400 // reduced number of uses, allowing other xforms. 401 if (N->use_empty() && N != &Dummy) { 402 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) 403 WorkList.push_back(N->getOperand(i).Val); 404 405 removeFromWorkList(N); 406 DAG.DeleteNode(N); 407 continue; 408 } 409 410 SDOperand RV = visit(N); 411 412 // If nothing happened, try a target-specific DAG combine. 413 if (RV.Val == 0) { 414 assert(N->getOpcode() != ISD::DELETED_NODE && 415 "Node was deleted but visit returned NULL!"); 416 if (N->getOpcode() >= ISD::BUILTIN_OP_END || 417 TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) 418 RV = TLI.PerformDAGCombine(N, DagCombineInfo); 419 } 420 421 if (RV.Val) { 422 ++NodesCombined; 423 // If we get back the same node we passed in, rather than a new node or 424 // zero, we know that the node must have defined multiple values and 425 // CombineTo was used. Since CombineTo takes care of the worklist 426 // mechanics for us, we have no work to do in this case. 427 if (RV.Val != N) { 428 assert(N->getOpcode() != ISD::DELETED_NODE && 429 RV.Val->getOpcode() != ISD::DELETED_NODE && 430 "Node was deleted but visit returned new node!"); 431 432 DEBUG(std::cerr << "\nReplacing "; N->dump(); 433 std::cerr << "\nWith: "; RV.Val->dump(&DAG); 434 std::cerr << '\n'); 435 std::vector<SDNode*> NowDead; 436 if (N->getNumValues() == RV.Val->getNumValues()) 437 DAG.ReplaceAllUsesWith(N, RV.Val, &NowDead); 438 else { 439 assert(N->getValueType(0) == RV.getValueType() && "Type mismatch"); 440 SDOperand OpV = RV; 441 DAG.ReplaceAllUsesWith(N, &OpV, &NowDead); 442 } 443 444 // Push the new node and any users onto the worklist 445 WorkList.push_back(RV.Val); 446 AddUsersToWorkList(RV.Val); 447 448 // Nodes can end up on the worklist more than once. Make sure we do 449 // not process a node that has been replaced. 450 removeFromWorkList(N); 451 for (unsigned i = 0, e = NowDead.size(); i != e; ++i) 452 removeFromWorkList(NowDead[i]); 453 454 // Finally, since the node is now dead, remove it from the graph. 455 DAG.DeleteNode(N); 456 } 457 } 458 } 459 460 // If the root changed (e.g. it was a dead load, update the root). 461 DAG.setRoot(Dummy.getValue()); 462} 463 464SDOperand DAGCombiner::visit(SDNode *N) { 465 switch(N->getOpcode()) { 466 default: break; 467 case ISD::TokenFactor: return visitTokenFactor(N); 468 case ISD::ADD: return visitADD(N); 469 case ISD::SUB: return visitSUB(N); 470 case ISD::MUL: return visitMUL(N); 471 case ISD::SDIV: return visitSDIV(N); 472 case ISD::UDIV: return visitUDIV(N); 473 case ISD::SREM: return visitSREM(N); 474 case ISD::UREM: return visitUREM(N); 475 case ISD::MULHU: return visitMULHU(N); 476 case ISD::MULHS: return visitMULHS(N); 477 case ISD::AND: return visitAND(N); 478 case ISD::OR: return visitOR(N); 479 case ISD::XOR: return visitXOR(N); 480 case ISD::SHL: return visitSHL(N); 481 case ISD::SRA: return visitSRA(N); 482 case ISD::SRL: return visitSRL(N); 483 case ISD::CTLZ: return visitCTLZ(N); 484 case ISD::CTTZ: return visitCTTZ(N); 485 case ISD::CTPOP: return visitCTPOP(N); 486 case ISD::SELECT: return visitSELECT(N); 487 case ISD::SELECT_CC: return visitSELECT_CC(N); 488 case ISD::SETCC: return visitSETCC(N); 489 case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N); 490 case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N); 491 case ISD::ANY_EXTEND: return visitANY_EXTEND(N); 492 case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N); 493 case ISD::TRUNCATE: return visitTRUNCATE(N); 494 case ISD::BIT_CONVERT: return visitBIT_CONVERT(N); 495 case ISD::VBIT_CONVERT: return visitVBIT_CONVERT(N); 496 case ISD::FADD: return visitFADD(N); 497 case ISD::FSUB: return visitFSUB(N); 498 case ISD::FMUL: return visitFMUL(N); 499 case ISD::FDIV: return visitFDIV(N); 500 case ISD::FREM: return visitFREM(N); 501 case ISD::FCOPYSIGN: return visitFCOPYSIGN(N); 502 case ISD::SINT_TO_FP: return visitSINT_TO_FP(N); 503 case ISD::UINT_TO_FP: return visitUINT_TO_FP(N); 504 case ISD::FP_TO_SINT: return visitFP_TO_SINT(N); 505 case ISD::FP_TO_UINT: return visitFP_TO_UINT(N); 506 case ISD::FP_ROUND: return visitFP_ROUND(N); 507 case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N); 508 case ISD::FP_EXTEND: return visitFP_EXTEND(N); 509 case ISD::FNEG: return visitFNEG(N); 510 case ISD::FABS: return visitFABS(N); 511 case ISD::BRCOND: return visitBRCOND(N); 512 case ISD::BR_CC: return visitBR_CC(N); 513 case ISD::LOAD: return visitLOAD(N); 514 case ISD::EXTLOAD: 515 case ISD::SEXTLOAD: 516 case ISD::ZEXTLOAD: return visitXEXTLOAD(N); 517 case ISD::STORE: return visitSTORE(N); 518 case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N); 519 case ISD::VINSERT_VECTOR_ELT: return visitVINSERT_VECTOR_ELT(N); 520 case ISD::VBUILD_VECTOR: return visitVBUILD_VECTOR(N); 521 case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); 522 case ISD::VVECTOR_SHUFFLE: return visitVVECTOR_SHUFFLE(N); 523 case ISD::VADD: return visitVBinOp(N, ISD::ADD , ISD::FADD); 524 case ISD::VSUB: return visitVBinOp(N, ISD::SUB , ISD::FSUB); 525 case ISD::VMUL: return visitVBinOp(N, ISD::MUL , ISD::FMUL); 526 case ISD::VSDIV: return visitVBinOp(N, ISD::SDIV, ISD::FDIV); 527 case ISD::VUDIV: return visitVBinOp(N, ISD::UDIV, ISD::UDIV); 528 case ISD::VAND: return visitVBinOp(N, ISD::AND , ISD::AND); 529 case ISD::VOR: return visitVBinOp(N, ISD::OR , ISD::OR); 530 case ISD::VXOR: return visitVBinOp(N, ISD::XOR , ISD::XOR); 531 } 532 return SDOperand(); 533} 534 535SDOperand DAGCombiner::visitTokenFactor(SDNode *N) { 536 // If the token factor has two operands and one is the entry token, replace 537 // the token factor with the other operand. 538 if (N->getNumOperands() == 2) { 539 if (N->getOperand(0).getOpcode() == ISD::EntryToken || 540 N->getOperand(0) == N->getOperand(1)) 541 return N->getOperand(1); 542 if (N->getOperand(1).getOpcode() == ISD::EntryToken) 543 return N->getOperand(0); 544 } 545 546 SmallVector<SDNode *, 8> TFs; // Set of token factor nodes. 547 SmallVector<SDOperand, 8> Ops; // Ops for replacing token factor. 548 549 // Add this ndoe to the token factor set. 550 TFs.push_back(N); 551 552 // Separate token factors from other operands. 553 for (unsigned i = 0, ie = N->getNumOperands(); i != ie; ++i) { 554 SDOperand Op = N->getOperand(i); 555 if (Op.getOpcode() == ISD::TokenFactor) 556 TFs.push_back(Op.Val); 557 else if (Op.getOpcode() != ISD::EntryToken) 558 Ops.push_back(Op); 559 } 560 561 // If there are token factor operands. 562 if (TFs.size() > 1) { 563 bool Changed = false; // If we should replace this token factor. 564 565 // For each token factor. 566 for (unsigned j = 1, je = TFs.size(); j != je; ++j) { 567 SDNode *TF = TFs[j]; 568 bool CanMerge = true; // Can we merge this token factor. 569 570 if (CombinerAA) { 571 if (!TF->hasOneUse()) { 572 // Check to see if all users point to members of the token factor set. 573 for (SDNode::use_iterator UI = TF->use_begin(), UE = TF->use_end(); 574 CanMerge && UI != UE; ++UI) { 575 SDNode *User = *UI; 576 CanMerge = User->getOpcode() == ISD::TokenFactor && 577 std::find(TFs.begin(), TFs.end(), User) != TFs.end(); 578 } 579 } 580 } else { 581 CanMerge = TF->hasOneUse(); 582 } 583 584 // If it's valid to merge. 585 if (CanMerge) { 586 // Remove dead token factor node. 587 AddToWorkList(TF); 588 589 // Make sure we don't duplicate operands. 590 unsigned m = Ops.size(); // Number of prior operands. 591 for (unsigned l = 0, le = TF->getNumOperands(); l != le; ++l) { 592 SDOperand Op = TF->getOperand(l); 593 if (std::find(Ops.begin(), Ops.end(), Op) == Ops.end()) 594 Ops.push_back(Op); 595 } 596 Changed = true; 597 } else { 598 // Can't merge this token factor. 599 Ops.push_back(SDOperand(TF, 0)); 600 } 601 } 602 603 // If we've change things around then replace token factor. 604 if (Changed) { 605 return DAG.getNode(ISD::TokenFactor, MVT::Other, &Ops[0], Ops.size()); 606 } 607 } 608 609 return SDOperand(); 610} 611 612SDOperand DAGCombiner::visitADD(SDNode *N) { 613 SDOperand N0 = N->getOperand(0); 614 SDOperand N1 = N->getOperand(1); 615 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 616 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 617 MVT::ValueType VT = N0.getValueType(); 618 619 // fold (add c1, c2) -> c1+c2 620 if (N0C && N1C) 621 return DAG.getNode(ISD::ADD, VT, N0, N1); 622 // canonicalize constant to RHS 623 if (N0C && !N1C) 624 return DAG.getNode(ISD::ADD, VT, N1, N0); 625 // fold (add x, 0) -> x 626 if (N1C && N1C->isNullValue()) 627 return N0; 628 // fold ((c1-A)+c2) -> (c1+c2)-A 629 if (N1C && N0.getOpcode() == ISD::SUB) 630 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0))) 631 return DAG.getNode(ISD::SUB, VT, 632 DAG.getConstant(N1C->getValue()+N0C->getValue(), VT), 633 N0.getOperand(1)); 634 // reassociate add 635 SDOperand RADD = ReassociateOps(ISD::ADD, N0, N1); 636 if (RADD.Val != 0) 637 return RADD; 638 // fold ((0-A) + B) -> B-A 639 if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) && 640 cast<ConstantSDNode>(N0.getOperand(0))->isNullValue()) 641 return DAG.getNode(ISD::SUB, VT, N1, N0.getOperand(1)); 642 // fold (A + (0-B)) -> A-B 643 if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) && 644 cast<ConstantSDNode>(N1.getOperand(0))->isNullValue()) 645 return DAG.getNode(ISD::SUB, VT, N0, N1.getOperand(1)); 646 // fold (A+(B-A)) -> B 647 if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1)) 648 return N1.getOperand(0); 649 650 if (!MVT::isVector(VT) && SimplifyDemandedBits(SDOperand(N, 0))) 651 return SDOperand(N, 0); 652 653 // fold (a+b) -> (a|b) iff a and b share no bits. 654 if (MVT::isInteger(VT) && !MVT::isVector(VT)) { 655 uint64_t LHSZero, LHSOne; 656 uint64_t RHSZero, RHSOne; 657 uint64_t Mask = MVT::getIntVTBitMask(VT); 658 TLI.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne); 659 if (LHSZero) { 660 TLI.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne); 661 662 // If all possibly-set bits on the LHS are clear on the RHS, return an OR. 663 // If all possibly-set bits on the RHS are clear on the LHS, return an OR. 664 if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) || 665 (LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask)) 666 return DAG.getNode(ISD::OR, VT, N0, N1); 667 } 668 } 669 670 return SDOperand(); 671} 672 673SDOperand DAGCombiner::visitSUB(SDNode *N) { 674 SDOperand N0 = N->getOperand(0); 675 SDOperand N1 = N->getOperand(1); 676 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val); 677 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 678 MVT::ValueType VT = N0.getValueType(); 679 680 // fold (sub x, x) -> 0 681 if (N0 == N1) 682 return DAG.getConstant(0, N->getValueType(0)); 683 // fold (sub c1, c2) -> c1-c2 684 if (N0C && N1C) 685 return DAG.getNode(ISD::SUB, VT, N0, N1); 686 // fold (sub x, c) -> (add x, -c) 687 if (N1C) 688 return DAG.getNode(ISD::ADD, VT, N0, DAG.getConstant(-N1C->getValue(), VT)); 689 // fold (A+B)-A -> B 690 if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1) 691 return N0.getOperand(1); 692 // fold (A+B)-B -> A 693 if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) 694 return N0.getOperand(0); 695 return SDOperand(); 696} 697 698SDOperand DAGCombiner::visitMUL(SDNode *N) { 699 SDOperand N0 = N->getOperand(0); 700 SDOperand N1 = N->getOperand(1); 701 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 702 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 703 MVT::ValueType VT = N0.getValueType(); 704 705 // fold (mul c1, c2) -> c1*c2 706 if (N0C && N1C) 707 return DAG.getNode(ISD::MUL, VT, N0, N1); 708 // canonicalize constant to RHS 709 if (N0C && !N1C) 710 return DAG.getNode(ISD::MUL, VT, N1, N0); 711 // fold (mul x, 0) -> 0 712 if (N1C && N1C->isNullValue()) 713 return N1; 714 // fold (mul x, -1) -> 0-x 715 if (N1C && N1C->isAllOnesValue()) 716 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0); 717 // fold (mul x, (1 << c)) -> x << c 718 if (N1C && isPowerOf2_64(N1C->getValue())) 719 return DAG.getNode(ISD::SHL, VT, N0, 720 DAG.getConstant(Log2_64(N1C->getValue()), 721 TLI.getShiftAmountTy())); 722 // fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c 723 if (N1C && isPowerOf2_64(-N1C->getSignExtended())) { 724 // FIXME: If the input is something that is easily negated (e.g. a 725 // single-use add), we should put the negate there. 726 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), 727 DAG.getNode(ISD::SHL, VT, N0, 728 DAG.getConstant(Log2_64(-N1C->getSignExtended()), 729 TLI.getShiftAmountTy()))); 730 } 731 732 // (mul (shl X, c1), c2) -> (mul X, c2 << c1) 733 if (N1C && N0.getOpcode() == ISD::SHL && 734 isa<ConstantSDNode>(N0.getOperand(1))) { 735 SDOperand C3 = DAG.getNode(ISD::SHL, VT, N1, N0.getOperand(1)); 736 AddToWorkList(C3.Val); 737 return DAG.getNode(ISD::MUL, VT, N0.getOperand(0), C3); 738 } 739 740 // Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one 741 // use. 742 { 743 SDOperand Sh(0,0), Y(0,0); 744 // Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)). 745 if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) && 746 N0.Val->hasOneUse()) { 747 Sh = N0; Y = N1; 748 } else if (N1.getOpcode() == ISD::SHL && 749 isa<ConstantSDNode>(N1.getOperand(1)) && N1.Val->hasOneUse()) { 750 Sh = N1; Y = N0; 751 } 752 if (Sh.Val) { 753 SDOperand Mul = DAG.getNode(ISD::MUL, VT, Sh.getOperand(0), Y); 754 return DAG.getNode(ISD::SHL, VT, Mul, Sh.getOperand(1)); 755 } 756 } 757 // fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2) 758 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() && 759 isa<ConstantSDNode>(N0.getOperand(1))) { 760 return DAG.getNode(ISD::ADD, VT, 761 DAG.getNode(ISD::MUL, VT, N0.getOperand(0), N1), 762 DAG.getNode(ISD::MUL, VT, N0.getOperand(1), N1)); 763 } 764 765 // reassociate mul 766 SDOperand RMUL = ReassociateOps(ISD::MUL, N0, N1); 767 if (RMUL.Val != 0) 768 return RMUL; 769 return SDOperand(); 770} 771 772SDOperand DAGCombiner::visitSDIV(SDNode *N) { 773 SDOperand N0 = N->getOperand(0); 774 SDOperand N1 = N->getOperand(1); 775 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val); 776 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 777 MVT::ValueType VT = N->getValueType(0); 778 779 // fold (sdiv c1, c2) -> c1/c2 780 if (N0C && N1C && !N1C->isNullValue()) 781 return DAG.getNode(ISD::SDIV, VT, N0, N1); 782 // fold (sdiv X, 1) -> X 783 if (N1C && N1C->getSignExtended() == 1LL) 784 return N0; 785 // fold (sdiv X, -1) -> 0-X 786 if (N1C && N1C->isAllOnesValue()) 787 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), N0); 788 // If we know the sign bits of both operands are zero, strength reduce to a 789 // udiv instead. Handles (X&15) /s 4 -> X&15 >> 2 790 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1); 791 if (TLI.MaskedValueIsZero(N1, SignBit) && 792 TLI.MaskedValueIsZero(N0, SignBit)) 793 return DAG.getNode(ISD::UDIV, N1.getValueType(), N0, N1); 794 // fold (sdiv X, pow2) -> simple ops after legalize 795 if (N1C && N1C->getValue() && !TLI.isIntDivCheap() && 796 (isPowerOf2_64(N1C->getSignExtended()) || 797 isPowerOf2_64(-N1C->getSignExtended()))) { 798 // If dividing by powers of two is cheap, then don't perform the following 799 // fold. 800 if (TLI.isPow2DivCheap()) 801 return SDOperand(); 802 int64_t pow2 = N1C->getSignExtended(); 803 int64_t abs2 = pow2 > 0 ? pow2 : -pow2; 804 unsigned lg2 = Log2_64(abs2); 805 // Splat the sign bit into the register 806 SDOperand SGN = DAG.getNode(ISD::SRA, VT, N0, 807 DAG.getConstant(MVT::getSizeInBits(VT)-1, 808 TLI.getShiftAmountTy())); 809 AddToWorkList(SGN.Val); 810 // Add (N0 < 0) ? abs2 - 1 : 0; 811 SDOperand SRL = DAG.getNode(ISD::SRL, VT, SGN, 812 DAG.getConstant(MVT::getSizeInBits(VT)-lg2, 813 TLI.getShiftAmountTy())); 814 SDOperand ADD = DAG.getNode(ISD::ADD, VT, N0, SRL); 815 AddToWorkList(SRL.Val); 816 AddToWorkList(ADD.Val); // Divide by pow2 817 SDOperand SRA = DAG.getNode(ISD::SRA, VT, ADD, 818 DAG.getConstant(lg2, TLI.getShiftAmountTy())); 819 // If we're dividing by a positive value, we're done. Otherwise, we must 820 // negate the result. 821 if (pow2 > 0) 822 return SRA; 823 AddToWorkList(SRA.Val); 824 return DAG.getNode(ISD::SUB, VT, DAG.getConstant(0, VT), SRA); 825 } 826 // if integer divide is expensive and we satisfy the requirements, emit an 827 // alternate sequence. 828 if (N1C && (N1C->getSignExtended() < -1 || N1C->getSignExtended() > 1) && 829 !TLI.isIntDivCheap()) { 830 SDOperand Op = BuildSDIV(N); 831 if (Op.Val) return Op; 832 } 833 return SDOperand(); 834} 835 836SDOperand DAGCombiner::visitUDIV(SDNode *N) { 837 SDOperand N0 = N->getOperand(0); 838 SDOperand N1 = N->getOperand(1); 839 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val); 840 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 841 MVT::ValueType VT = N->getValueType(0); 842 843 // fold (udiv c1, c2) -> c1/c2 844 if (N0C && N1C && !N1C->isNullValue()) 845 return DAG.getNode(ISD::UDIV, VT, N0, N1); 846 // fold (udiv x, (1 << c)) -> x >>u c 847 if (N1C && isPowerOf2_64(N1C->getValue())) 848 return DAG.getNode(ISD::SRL, VT, N0, 849 DAG.getConstant(Log2_64(N1C->getValue()), 850 TLI.getShiftAmountTy())); 851 // fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2 852 if (N1.getOpcode() == ISD::SHL) { 853 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 854 if (isPowerOf2_64(SHC->getValue())) { 855 MVT::ValueType ADDVT = N1.getOperand(1).getValueType(); 856 SDOperand Add = DAG.getNode(ISD::ADD, ADDVT, N1.getOperand(1), 857 DAG.getConstant(Log2_64(SHC->getValue()), 858 ADDVT)); 859 AddToWorkList(Add.Val); 860 return DAG.getNode(ISD::SRL, VT, N0, Add); 861 } 862 } 863 } 864 // fold (udiv x, c) -> alternate 865 if (N1C && N1C->getValue() && !TLI.isIntDivCheap()) { 866 SDOperand Op = BuildUDIV(N); 867 if (Op.Val) return Op; 868 } 869 return SDOperand(); 870} 871 872SDOperand DAGCombiner::visitSREM(SDNode *N) { 873 SDOperand N0 = N->getOperand(0); 874 SDOperand N1 = N->getOperand(1); 875 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 876 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 877 MVT::ValueType VT = N->getValueType(0); 878 879 // fold (srem c1, c2) -> c1%c2 880 if (N0C && N1C && !N1C->isNullValue()) 881 return DAG.getNode(ISD::SREM, VT, N0, N1); 882 // If we know the sign bits of both operands are zero, strength reduce to a 883 // urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15 884 uint64_t SignBit = 1ULL << (MVT::getSizeInBits(VT)-1); 885 if (TLI.MaskedValueIsZero(N1, SignBit) && 886 TLI.MaskedValueIsZero(N0, SignBit)) 887 return DAG.getNode(ISD::UREM, VT, N0, N1); 888 return SDOperand(); 889} 890 891SDOperand DAGCombiner::visitUREM(SDNode *N) { 892 SDOperand N0 = N->getOperand(0); 893 SDOperand N1 = N->getOperand(1); 894 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 895 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 896 MVT::ValueType VT = N->getValueType(0); 897 898 // fold (urem c1, c2) -> c1%c2 899 if (N0C && N1C && !N1C->isNullValue()) 900 return DAG.getNode(ISD::UREM, VT, N0, N1); 901 // fold (urem x, pow2) -> (and x, pow2-1) 902 if (N1C && !N1C->isNullValue() && isPowerOf2_64(N1C->getValue())) 903 return DAG.getNode(ISD::AND, VT, N0, DAG.getConstant(N1C->getValue()-1,VT)); 904 // fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1)) 905 if (N1.getOpcode() == ISD::SHL) { 906 if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) { 907 if (isPowerOf2_64(SHC->getValue())) { 908 SDOperand Add = DAG.getNode(ISD::ADD, VT, N1,DAG.getConstant(~0ULL,VT)); 909 AddToWorkList(Add.Val); 910 return DAG.getNode(ISD::AND, VT, N0, Add); 911 } 912 } 913 } 914 return SDOperand(); 915} 916 917SDOperand DAGCombiner::visitMULHS(SDNode *N) { 918 SDOperand N0 = N->getOperand(0); 919 SDOperand N1 = N->getOperand(1); 920 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 921 922 // fold (mulhs x, 0) -> 0 923 if (N1C && N1C->isNullValue()) 924 return N1; 925 // fold (mulhs x, 1) -> (sra x, size(x)-1) 926 if (N1C && N1C->getValue() == 1) 927 return DAG.getNode(ISD::SRA, N0.getValueType(), N0, 928 DAG.getConstant(MVT::getSizeInBits(N0.getValueType())-1, 929 TLI.getShiftAmountTy())); 930 return SDOperand(); 931} 932 933SDOperand DAGCombiner::visitMULHU(SDNode *N) { 934 SDOperand N0 = N->getOperand(0); 935 SDOperand N1 = N->getOperand(1); 936 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 937 938 // fold (mulhu x, 0) -> 0 939 if (N1C && N1C->isNullValue()) 940 return N1; 941 // fold (mulhu x, 1) -> 0 942 if (N1C && N1C->getValue() == 1) 943 return DAG.getConstant(0, N0.getValueType()); 944 return SDOperand(); 945} 946 947/// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with 948/// two operands of the same opcode, try to simplify it. 949SDOperand DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) { 950 SDOperand N0 = N->getOperand(0), N1 = N->getOperand(1); 951 MVT::ValueType VT = N0.getValueType(); 952 assert(N0.getOpcode() == N1.getOpcode() && "Bad input!"); 953 954 // For each of OP in AND/OR/XOR: 955 // fold (OP (zext x), (zext y)) -> (zext (OP x, y)) 956 // fold (OP (sext x), (sext y)) -> (sext (OP x, y)) 957 // fold (OP (aext x), (aext y)) -> (aext (OP x, y)) 958 // fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y)) 959 if ((N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND|| 960 N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::TRUNCATE) && 961 N0.getOperand(0).getValueType() == N1.getOperand(0).getValueType()) { 962 SDOperand ORNode = DAG.getNode(N->getOpcode(), 963 N0.getOperand(0).getValueType(), 964 N0.getOperand(0), N1.getOperand(0)); 965 AddToWorkList(ORNode.Val); 966 return DAG.getNode(N0.getOpcode(), VT, ORNode); 967 } 968 969 // For each of OP in SHL/SRL/SRA/AND... 970 // fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z) 971 // fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z) 972 // fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z) 973 if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL || 974 N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) && 975 N0.getOperand(1) == N1.getOperand(1)) { 976 SDOperand ORNode = DAG.getNode(N->getOpcode(), 977 N0.getOperand(0).getValueType(), 978 N0.getOperand(0), N1.getOperand(0)); 979 AddToWorkList(ORNode.Val); 980 return DAG.getNode(N0.getOpcode(), VT, ORNode, N0.getOperand(1)); 981 } 982 983 return SDOperand(); 984} 985 986SDOperand DAGCombiner::visitAND(SDNode *N) { 987 SDOperand N0 = N->getOperand(0); 988 SDOperand N1 = N->getOperand(1); 989 SDOperand LL, LR, RL, RR, CC0, CC1; 990 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 991 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 992 MVT::ValueType VT = N1.getValueType(); 993 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 994 995 // fold (and c1, c2) -> c1&c2 996 if (N0C && N1C) 997 return DAG.getNode(ISD::AND, VT, N0, N1); 998 // canonicalize constant to RHS 999 if (N0C && !N1C) 1000 return DAG.getNode(ISD::AND, VT, N1, N0); 1001 // fold (and x, -1) -> x 1002 if (N1C && N1C->isAllOnesValue()) 1003 return N0; 1004 // if (and x, c) is known to be zero, return 0 1005 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT))) 1006 return DAG.getConstant(0, VT); 1007 // reassociate and 1008 SDOperand RAND = ReassociateOps(ISD::AND, N0, N1); 1009 if (RAND.Val != 0) 1010 return RAND; 1011 // fold (and (or x, 0xFFFF), 0xFF) -> 0xFF 1012 if (N1C && N0.getOpcode() == ISD::OR) 1013 if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 1014 if ((ORI->getValue() & N1C->getValue()) == N1C->getValue()) 1015 return N1; 1016 // fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits. 1017 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 1018 unsigned InMask = MVT::getIntVTBitMask(N0.getOperand(0).getValueType()); 1019 if (TLI.MaskedValueIsZero(N0.getOperand(0), 1020 ~N1C->getValue() & InMask)) { 1021 SDOperand Zext = DAG.getNode(ISD::ZERO_EXTEND, N0.getValueType(), 1022 N0.getOperand(0)); 1023 1024 // Replace uses of the AND with uses of the Zero extend node. 1025 CombineTo(N, Zext); 1026 1027 // We actually want to replace all uses of the any_extend with the 1028 // zero_extend, to avoid duplicating things. This will later cause this 1029 // AND to be folded. 1030 CombineTo(N0.Val, Zext); 1031 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1032 } 1033 } 1034 // fold (and (setcc x), (setcc y)) -> (setcc (and x, y)) 1035 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 1036 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 1037 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 1038 1039 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 1040 MVT::isInteger(LL.getValueType())) { 1041 // fold (X == 0) & (Y == 0) -> (X|Y == 0) 1042 if (cast<ConstantSDNode>(LR)->getValue() == 0 && Op1 == ISD::SETEQ) { 1043 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1044 AddToWorkList(ORNode.Val); 1045 return DAG.getSetCC(VT, ORNode, LR, Op1); 1046 } 1047 // fold (X == -1) & (Y == -1) -> (X&Y == -1) 1048 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) { 1049 SDOperand ANDNode = DAG.getNode(ISD::AND, LR.getValueType(), LL, RL); 1050 AddToWorkList(ANDNode.Val); 1051 return DAG.getSetCC(VT, ANDNode, LR, Op1); 1052 } 1053 // fold (X > -1) & (Y > -1) -> (X|Y > -1) 1054 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) { 1055 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1056 AddToWorkList(ORNode.Val); 1057 return DAG.getSetCC(VT, ORNode, LR, Op1); 1058 } 1059 } 1060 // canonicalize equivalent to ll == rl 1061 if (LL == RR && LR == RL) { 1062 Op1 = ISD::getSetCCSwappedOperands(Op1); 1063 std::swap(RL, RR); 1064 } 1065 if (LL == RL && LR == RR) { 1066 bool isInteger = MVT::isInteger(LL.getValueType()); 1067 ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger); 1068 if (Result != ISD::SETCC_INVALID) 1069 return DAG.getSetCC(N0.getValueType(), LL, LR, Result); 1070 } 1071 } 1072 1073 // Simplify: and (op x...), (op y...) -> (op (and x, y)) 1074 if (N0.getOpcode() == N1.getOpcode()) { 1075 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1076 if (Tmp.Val) return Tmp; 1077 } 1078 1079 // fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1) 1080 // fold (and (sra)) -> (and (srl)) when possible. 1081 if (!MVT::isVector(VT) && 1082 SimplifyDemandedBits(SDOperand(N, 0))) 1083 return SDOperand(N, 0); 1084 // fold (zext_inreg (extload x)) -> (zextload x) 1085 if (N0.getOpcode() == ISD::EXTLOAD) { 1086 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT(); 1087 // If we zero all the possible extended bits, then we can turn this into 1088 // a zextload if we are running before legalize or the operation is legal. 1089 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) && 1090 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) { 1091 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0), 1092 N0.getOperand(1), N0.getOperand(2), 1093 EVT); 1094 AddToWorkList(N); 1095 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1)); 1096 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1097 } 1098 } 1099 // fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use 1100 if (N0.getOpcode() == ISD::SEXTLOAD && N0.hasOneUse()) { 1101 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT(); 1102 // If we zero all the possible extended bits, then we can turn this into 1103 // a zextload if we are running before legalize or the operation is legal. 1104 if (TLI.MaskedValueIsZero(N1, ~0ULL << MVT::getSizeInBits(EVT)) && 1105 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) { 1106 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0), 1107 N0.getOperand(1), N0.getOperand(2), 1108 EVT); 1109 AddToWorkList(N); 1110 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1)); 1111 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1112 } 1113 } 1114 1115 // fold (and (load x), 255) -> (zextload x, i8) 1116 // fold (and (extload x, i16), 255) -> (zextload x, i8) 1117 if (N1C && 1118 (N0.getOpcode() == ISD::LOAD || N0.getOpcode() == ISD::EXTLOAD || 1119 N0.getOpcode() == ISD::ZEXTLOAD) && 1120 N0.hasOneUse()) { 1121 MVT::ValueType EVT, LoadedVT; 1122 if (N1C->getValue() == 255) 1123 EVT = MVT::i8; 1124 else if (N1C->getValue() == 65535) 1125 EVT = MVT::i16; 1126 else if (N1C->getValue() == ~0U) 1127 EVT = MVT::i32; 1128 else 1129 EVT = MVT::Other; 1130 1131 LoadedVT = N0.getOpcode() == ISD::LOAD ? VT : 1132 cast<VTSDNode>(N0.getOperand(3))->getVT(); 1133 if (EVT != MVT::Other && LoadedVT > EVT && 1134 (!AfterLegalize || TLI.isOperationLegal(ISD::ZEXTLOAD, EVT))) { 1135 MVT::ValueType PtrType = N0.getOperand(1).getValueType(); 1136 // For big endian targets, we need to add an offset to the pointer to load 1137 // the correct bytes. For little endian systems, we merely need to read 1138 // fewer bytes from the same pointer. 1139 unsigned PtrOff = 1140 (MVT::getSizeInBits(LoadedVT) - MVT::getSizeInBits(EVT)) / 8; 1141 SDOperand NewPtr = N0.getOperand(1); 1142 if (!TLI.isLittleEndian()) 1143 NewPtr = DAG.getNode(ISD::ADD, PtrType, NewPtr, 1144 DAG.getConstant(PtrOff, PtrType)); 1145 AddToWorkList(NewPtr.Val); 1146 SDOperand Load = 1147 DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0), NewPtr, 1148 N0.getOperand(2), EVT); 1149 AddToWorkList(N); 1150 CombineTo(N0.Val, Load, Load.getValue(1)); 1151 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1152 } 1153 } 1154 1155 return SDOperand(); 1156} 1157 1158SDOperand DAGCombiner::visitOR(SDNode *N) { 1159 SDOperand N0 = N->getOperand(0); 1160 SDOperand N1 = N->getOperand(1); 1161 SDOperand LL, LR, RL, RR, CC0, CC1; 1162 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1163 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1164 MVT::ValueType VT = N1.getValueType(); 1165 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 1166 1167 // fold (or c1, c2) -> c1|c2 1168 if (N0C && N1C) 1169 return DAG.getNode(ISD::OR, VT, N0, N1); 1170 // canonicalize constant to RHS 1171 if (N0C && !N1C) 1172 return DAG.getNode(ISD::OR, VT, N1, N0); 1173 // fold (or x, 0) -> x 1174 if (N1C && N1C->isNullValue()) 1175 return N0; 1176 // fold (or x, -1) -> -1 1177 if (N1C && N1C->isAllOnesValue()) 1178 return N1; 1179 // fold (or x, c) -> c iff (x & ~c) == 0 1180 if (N1C && 1181 TLI.MaskedValueIsZero(N0,~N1C->getValue() & (~0ULL>>(64-OpSizeInBits)))) 1182 return N1; 1183 // reassociate or 1184 SDOperand ROR = ReassociateOps(ISD::OR, N0, N1); 1185 if (ROR.Val != 0) 1186 return ROR; 1187 // Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2) 1188 if (N1C && N0.getOpcode() == ISD::AND && N0.Val->hasOneUse() && 1189 isa<ConstantSDNode>(N0.getOperand(1))) { 1190 ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1)); 1191 return DAG.getNode(ISD::AND, VT, DAG.getNode(ISD::OR, VT, N0.getOperand(0), 1192 N1), 1193 DAG.getConstant(N1C->getValue() | C1->getValue(), VT)); 1194 } 1195 // fold (or (setcc x), (setcc y)) -> (setcc (or x, y)) 1196 if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){ 1197 ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get(); 1198 ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get(); 1199 1200 if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 && 1201 MVT::isInteger(LL.getValueType())) { 1202 // fold (X != 0) | (Y != 0) -> (X|Y != 0) 1203 // fold (X < 0) | (Y < 0) -> (X|Y < 0) 1204 if (cast<ConstantSDNode>(LR)->getValue() == 0 && 1205 (Op1 == ISD::SETNE || Op1 == ISD::SETLT)) { 1206 SDOperand ORNode = DAG.getNode(ISD::OR, LR.getValueType(), LL, RL); 1207 AddToWorkList(ORNode.Val); 1208 return DAG.getSetCC(VT, ORNode, LR, Op1); 1209 } 1210 // fold (X != -1) | (Y != -1) -> (X&Y != -1) 1211 // fold (X > -1) | (Y > -1) -> (X&Y > -1) 1212 if (cast<ConstantSDNode>(LR)->isAllOnesValue() && 1213 (Op1 == ISD::SETNE || Op1 == ISD::SETGT)) { 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 } 1219 // canonicalize equivalent to ll == rl 1220 if (LL == RR && LR == RL) { 1221 Op1 = ISD::getSetCCSwappedOperands(Op1); 1222 std::swap(RL, RR); 1223 } 1224 if (LL == RL && LR == RR) { 1225 bool isInteger = MVT::isInteger(LL.getValueType()); 1226 ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger); 1227 if (Result != ISD::SETCC_INVALID) 1228 return DAG.getSetCC(N0.getValueType(), LL, LR, Result); 1229 } 1230 } 1231 1232 // Simplify: or (op x...), (op y...) -> (op (or x, y)) 1233 if (N0.getOpcode() == N1.getOpcode()) { 1234 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1235 if (Tmp.Val) return Tmp; 1236 } 1237 1238 // (X & C1) | (Y & C2) -> (X|Y) & C3 if possible. 1239 if (N0.getOpcode() == ISD::AND && 1240 N1.getOpcode() == ISD::AND && 1241 N0.getOperand(1).getOpcode() == ISD::Constant && 1242 N1.getOperand(1).getOpcode() == ISD::Constant && 1243 // Don't increase # computations. 1244 (N0.Val->hasOneUse() || N1.Val->hasOneUse())) { 1245 // We can only do this xform if we know that bits from X that are set in C2 1246 // but not in C1 are already zero. Likewise for Y. 1247 uint64_t LHSMask = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1248 uint64_t RHSMask = cast<ConstantSDNode>(N1.getOperand(1))->getValue(); 1249 1250 if (TLI.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) && 1251 TLI.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) { 1252 SDOperand X =DAG.getNode(ISD::OR, VT, N0.getOperand(0), N1.getOperand(0)); 1253 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(LHSMask|RHSMask, VT)); 1254 } 1255 } 1256 1257 1258 // See if this is some rotate idiom. 1259 if (SDNode *Rot = MatchRotate(N0, N1)) 1260 return SDOperand(Rot, 0); 1261 1262 return SDOperand(); 1263} 1264 1265 1266/// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present. 1267static bool MatchRotateHalf(SDOperand Op, SDOperand &Shift, SDOperand &Mask) { 1268 if (Op.getOpcode() == ISD::AND) { 1269 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(Op.getOperand(1))) { 1270 Mask = Op.getOperand(1); 1271 Op = Op.getOperand(0); 1272 } else { 1273 return false; 1274 } 1275 } 1276 1277 if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) { 1278 Shift = Op; 1279 return true; 1280 } 1281 return false; 1282} 1283 1284 1285// MatchRotate - Handle an 'or' of two operands. If this is one of the many 1286// idioms for rotate, and if the target supports rotation instructions, generate 1287// a rot[lr]. 1288SDNode *DAGCombiner::MatchRotate(SDOperand LHS, SDOperand RHS) { 1289 // Must be a legal type. Expanded an promoted things won't work with rotates. 1290 MVT::ValueType VT = LHS.getValueType(); 1291 if (!TLI.isTypeLegal(VT)) return 0; 1292 1293 // The target must have at least one rotate flavor. 1294 bool HasROTL = TLI.isOperationLegal(ISD::ROTL, VT); 1295 bool HasROTR = TLI.isOperationLegal(ISD::ROTR, VT); 1296 if (!HasROTL && !HasROTR) return 0; 1297 1298 // Match "(X shl/srl V1) & V2" where V2 may not be present. 1299 SDOperand LHSShift; // The shift. 1300 SDOperand LHSMask; // AND value if any. 1301 if (!MatchRotateHalf(LHS, LHSShift, LHSMask)) 1302 return 0; // Not part of a rotate. 1303 1304 SDOperand RHSShift; // The shift. 1305 SDOperand RHSMask; // AND value if any. 1306 if (!MatchRotateHalf(RHS, RHSShift, RHSMask)) 1307 return 0; // Not part of a rotate. 1308 1309 if (LHSShift.getOperand(0) != RHSShift.getOperand(0)) 1310 return 0; // Not shifting the same value. 1311 1312 if (LHSShift.getOpcode() == RHSShift.getOpcode()) 1313 return 0; // Shifts must disagree. 1314 1315 // Canonicalize shl to left side in a shl/srl pair. 1316 if (RHSShift.getOpcode() == ISD::SHL) { 1317 std::swap(LHS, RHS); 1318 std::swap(LHSShift, RHSShift); 1319 std::swap(LHSMask , RHSMask ); 1320 } 1321 1322 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 1323 1324 // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1) 1325 // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2) 1326 if (LHSShift.getOperand(1).getOpcode() == ISD::Constant && 1327 RHSShift.getOperand(1).getOpcode() == ISD::Constant) { 1328 uint64_t LShVal = cast<ConstantSDNode>(LHSShift.getOperand(1))->getValue(); 1329 uint64_t RShVal = cast<ConstantSDNode>(RHSShift.getOperand(1))->getValue(); 1330 if ((LShVal + RShVal) != OpSizeInBits) 1331 return 0; 1332 1333 SDOperand Rot; 1334 if (HasROTL) 1335 Rot = DAG.getNode(ISD::ROTL, VT, LHSShift.getOperand(0), 1336 LHSShift.getOperand(1)); 1337 else 1338 Rot = DAG.getNode(ISD::ROTR, VT, LHSShift.getOperand(0), 1339 RHSShift.getOperand(1)); 1340 1341 // If there is an AND of either shifted operand, apply it to the result. 1342 if (LHSMask.Val || RHSMask.Val) { 1343 uint64_t Mask = MVT::getIntVTBitMask(VT); 1344 1345 if (LHSMask.Val) { 1346 uint64_t RHSBits = (1ULL << LShVal)-1; 1347 Mask &= cast<ConstantSDNode>(LHSMask)->getValue() | RHSBits; 1348 } 1349 if (RHSMask.Val) { 1350 uint64_t LHSBits = ~((1ULL << (OpSizeInBits-RShVal))-1); 1351 Mask &= cast<ConstantSDNode>(RHSMask)->getValue() | LHSBits; 1352 } 1353 1354 Rot = DAG.getNode(ISD::AND, VT, Rot, DAG.getConstant(Mask, VT)); 1355 } 1356 1357 return Rot.Val; 1358 } 1359 1360 // If there is a mask here, and we have a variable shift, we can't be sure 1361 // that we're masking out the right stuff. 1362 if (LHSMask.Val || RHSMask.Val) 1363 return 0; 1364 1365 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y) 1366 // fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y)) 1367 if (RHSShift.getOperand(1).getOpcode() == ISD::SUB && 1368 LHSShift.getOperand(1) == RHSShift.getOperand(1).getOperand(1)) { 1369 if (ConstantSDNode *SUBC = 1370 dyn_cast<ConstantSDNode>(RHSShift.getOperand(1).getOperand(0))) { 1371 if (SUBC->getValue() == OpSizeInBits) 1372 if (HasROTL) 1373 return DAG.getNode(ISD::ROTL, VT, LHSShift.getOperand(0), 1374 LHSShift.getOperand(1)).Val; 1375 else 1376 return DAG.getNode(ISD::ROTR, VT, LHSShift.getOperand(0), 1377 LHSShift.getOperand(1)).Val; 1378 } 1379 } 1380 1381 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y) 1382 // fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y)) 1383 if (LHSShift.getOperand(1).getOpcode() == ISD::SUB && 1384 RHSShift.getOperand(1) == LHSShift.getOperand(1).getOperand(1)) { 1385 if (ConstantSDNode *SUBC = 1386 dyn_cast<ConstantSDNode>(LHSShift.getOperand(1).getOperand(0))) { 1387 if (SUBC->getValue() == OpSizeInBits) 1388 if (HasROTL) 1389 return DAG.getNode(ISD::ROTL, VT, LHSShift.getOperand(0), 1390 LHSShift.getOperand(1)).Val; 1391 else 1392 return DAG.getNode(ISD::ROTR, VT, LHSShift.getOperand(0), 1393 RHSShift.getOperand(1)).Val; 1394 } 1395 } 1396 1397 return 0; 1398} 1399 1400 1401SDOperand DAGCombiner::visitXOR(SDNode *N) { 1402 SDOperand N0 = N->getOperand(0); 1403 SDOperand N1 = N->getOperand(1); 1404 SDOperand LHS, RHS, CC; 1405 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1406 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1407 MVT::ValueType VT = N0.getValueType(); 1408 1409 // fold (xor c1, c2) -> c1^c2 1410 if (N0C && N1C) 1411 return DAG.getNode(ISD::XOR, VT, N0, N1); 1412 // canonicalize constant to RHS 1413 if (N0C && !N1C) 1414 return DAG.getNode(ISD::XOR, VT, N1, N0); 1415 // fold (xor x, 0) -> x 1416 if (N1C && N1C->isNullValue()) 1417 return N0; 1418 // reassociate xor 1419 SDOperand RXOR = ReassociateOps(ISD::XOR, N0, N1); 1420 if (RXOR.Val != 0) 1421 return RXOR; 1422 // fold !(x cc y) -> (x !cc y) 1423 if (N1C && N1C->getValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) { 1424 bool isInt = MVT::isInteger(LHS.getValueType()); 1425 ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(), 1426 isInt); 1427 if (N0.getOpcode() == ISD::SETCC) 1428 return DAG.getSetCC(VT, LHS, RHS, NotCC); 1429 if (N0.getOpcode() == ISD::SELECT_CC) 1430 return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),N0.getOperand(3),NotCC); 1431 assert(0 && "Unhandled SetCC Equivalent!"); 1432 abort(); 1433 } 1434 // fold !(x or y) -> (!x and !y) iff x or y are setcc 1435 if (N1C && N1C->getValue() == 1 && 1436 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 1437 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1); 1438 if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) { 1439 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 1440 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS 1441 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS 1442 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val); 1443 return DAG.getNode(NewOpcode, VT, LHS, RHS); 1444 } 1445 } 1446 // fold !(x or y) -> (!x and !y) iff x or y are constants 1447 if (N1C && N1C->isAllOnesValue() && 1448 (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { 1449 SDOperand LHS = N0.getOperand(0), RHS = N0.getOperand(1); 1450 if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) { 1451 unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND; 1452 LHS = DAG.getNode(ISD::XOR, VT, LHS, N1); // RHS = ~LHS 1453 RHS = DAG.getNode(ISD::XOR, VT, RHS, N1); // RHS = ~RHS 1454 AddToWorkList(LHS.Val); AddToWorkList(RHS.Val); 1455 return DAG.getNode(NewOpcode, VT, LHS, RHS); 1456 } 1457 } 1458 // fold (xor (xor x, c1), c2) -> (xor x, c1^c2) 1459 if (N1C && N0.getOpcode() == ISD::XOR) { 1460 ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0)); 1461 ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); 1462 if (N00C) 1463 return DAG.getNode(ISD::XOR, VT, N0.getOperand(1), 1464 DAG.getConstant(N1C->getValue()^N00C->getValue(), VT)); 1465 if (N01C) 1466 return DAG.getNode(ISD::XOR, VT, N0.getOperand(0), 1467 DAG.getConstant(N1C->getValue()^N01C->getValue(), VT)); 1468 } 1469 // fold (xor x, x) -> 0 1470 if (N0 == N1) { 1471 if (!MVT::isVector(VT)) { 1472 return DAG.getConstant(0, VT); 1473 } else if (!AfterLegalize || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) { 1474 // Produce a vector of zeros. 1475 SDOperand El = DAG.getConstant(0, MVT::getVectorBaseType(VT)); 1476 std::vector<SDOperand> Ops(MVT::getVectorNumElements(VT), El); 1477 return DAG.getNode(ISD::BUILD_VECTOR, VT, &Ops[0], Ops.size()); 1478 } 1479 } 1480 1481 // Simplify: xor (op x...), (op y...) -> (op (xor x, y)) 1482 if (N0.getOpcode() == N1.getOpcode()) { 1483 SDOperand Tmp = SimplifyBinOpWithSameOpcodeHands(N); 1484 if (Tmp.Val) return Tmp; 1485 } 1486 1487 // Simplify the expression using non-local knowledge. 1488 if (!MVT::isVector(VT) && 1489 SimplifyDemandedBits(SDOperand(N, 0))) 1490 return SDOperand(N, 0); 1491 1492 return SDOperand(); 1493} 1494 1495SDOperand DAGCombiner::visitSHL(SDNode *N) { 1496 SDOperand N0 = N->getOperand(0); 1497 SDOperand N1 = N->getOperand(1); 1498 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1499 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1500 MVT::ValueType VT = N0.getValueType(); 1501 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 1502 1503 // fold (shl c1, c2) -> c1<<c2 1504 if (N0C && N1C) 1505 return DAG.getNode(ISD::SHL, VT, N0, N1); 1506 // fold (shl 0, x) -> 0 1507 if (N0C && N0C->isNullValue()) 1508 return N0; 1509 // fold (shl x, c >= size(x)) -> undef 1510 if (N1C && N1C->getValue() >= OpSizeInBits) 1511 return DAG.getNode(ISD::UNDEF, VT); 1512 // fold (shl x, 0) -> x 1513 if (N1C && N1C->isNullValue()) 1514 return N0; 1515 // if (shl x, c) is known to be zero, return 0 1516 if (TLI.MaskedValueIsZero(SDOperand(N, 0), MVT::getIntVTBitMask(VT))) 1517 return DAG.getConstant(0, VT); 1518 if (SimplifyDemandedBits(SDOperand(N, 0))) 1519 return SDOperand(N, 0); 1520 // fold (shl (shl x, c1), c2) -> 0 or (shl x, c1+c2) 1521 if (N1C && N0.getOpcode() == ISD::SHL && 1522 N0.getOperand(1).getOpcode() == ISD::Constant) { 1523 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1524 uint64_t c2 = N1C->getValue(); 1525 if (c1 + c2 > OpSizeInBits) 1526 return DAG.getConstant(0, VT); 1527 return DAG.getNode(ISD::SHL, VT, N0.getOperand(0), 1528 DAG.getConstant(c1 + c2, N1.getValueType())); 1529 } 1530 // fold (shl (srl x, c1), c2) -> (shl (and x, -1 << c1), c2-c1) or 1531 // (srl (and x, -1 << c1), c1-c2) 1532 if (N1C && N0.getOpcode() == ISD::SRL && 1533 N0.getOperand(1).getOpcode() == ISD::Constant) { 1534 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1535 uint64_t c2 = N1C->getValue(); 1536 SDOperand Mask = DAG.getNode(ISD::AND, VT, N0.getOperand(0), 1537 DAG.getConstant(~0ULL << c1, VT)); 1538 if (c2 > c1) 1539 return DAG.getNode(ISD::SHL, VT, Mask, 1540 DAG.getConstant(c2-c1, N1.getValueType())); 1541 else 1542 return DAG.getNode(ISD::SRL, VT, Mask, 1543 DAG.getConstant(c1-c2, N1.getValueType())); 1544 } 1545 // fold (shl (sra x, c1), c1) -> (and x, -1 << c1) 1546 if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) 1547 return DAG.getNode(ISD::AND, VT, N0.getOperand(0), 1548 DAG.getConstant(~0ULL << N1C->getValue(), VT)); 1549 // fold (shl (add x, c1), c2) -> (add (shl x, c2), c1<<c2) 1550 if (N1C && N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse() && 1551 isa<ConstantSDNode>(N0.getOperand(1))) { 1552 return DAG.getNode(ISD::ADD, VT, 1553 DAG.getNode(ISD::SHL, VT, N0.getOperand(0), N1), 1554 DAG.getNode(ISD::SHL, VT, N0.getOperand(1), N1)); 1555 } 1556 return SDOperand(); 1557} 1558 1559SDOperand DAGCombiner::visitSRA(SDNode *N) { 1560 SDOperand N0 = N->getOperand(0); 1561 SDOperand N1 = N->getOperand(1); 1562 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1563 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1564 MVT::ValueType VT = N0.getValueType(); 1565 1566 // fold (sra c1, c2) -> c1>>c2 1567 if (N0C && N1C) 1568 return DAG.getNode(ISD::SRA, VT, N0, N1); 1569 // fold (sra 0, x) -> 0 1570 if (N0C && N0C->isNullValue()) 1571 return N0; 1572 // fold (sra -1, x) -> -1 1573 if (N0C && N0C->isAllOnesValue()) 1574 return N0; 1575 // fold (sra x, c >= size(x)) -> undef 1576 if (N1C && N1C->getValue() >= MVT::getSizeInBits(VT)) 1577 return DAG.getNode(ISD::UNDEF, VT); 1578 // fold (sra x, 0) -> x 1579 if (N1C && N1C->isNullValue()) 1580 return N0; 1581 // fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports 1582 // sext_inreg. 1583 if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) { 1584 unsigned LowBits = MVT::getSizeInBits(VT) - (unsigned)N1C->getValue(); 1585 MVT::ValueType EVT; 1586 switch (LowBits) { 1587 default: EVT = MVT::Other; break; 1588 case 1: EVT = MVT::i1; break; 1589 case 8: EVT = MVT::i8; break; 1590 case 16: EVT = MVT::i16; break; 1591 case 32: EVT = MVT::i32; break; 1592 } 1593 if (EVT > MVT::Other && TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, EVT)) 1594 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), 1595 DAG.getValueType(EVT)); 1596 } 1597 1598 // fold (sra (sra x, c1), c2) -> (sra x, c1+c2) 1599 if (N1C && N0.getOpcode() == ISD::SRA) { 1600 if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 1601 unsigned Sum = N1C->getValue() + C1->getValue(); 1602 if (Sum >= MVT::getSizeInBits(VT)) Sum = MVT::getSizeInBits(VT)-1; 1603 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), 1604 DAG.getConstant(Sum, N1C->getValueType(0))); 1605 } 1606 } 1607 1608 // Simplify, based on bits shifted out of the LHS. 1609 if (N1C && SimplifyDemandedBits(SDOperand(N, 0))) 1610 return SDOperand(N, 0); 1611 1612 1613 // If the sign bit is known to be zero, switch this to a SRL. 1614 if (TLI.MaskedValueIsZero(N0, MVT::getIntVTSignBit(VT))) 1615 return DAG.getNode(ISD::SRL, VT, N0, N1); 1616 return SDOperand(); 1617} 1618 1619SDOperand DAGCombiner::visitSRL(SDNode *N) { 1620 SDOperand N0 = N->getOperand(0); 1621 SDOperand N1 = N->getOperand(1); 1622 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1623 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1624 MVT::ValueType VT = N0.getValueType(); 1625 unsigned OpSizeInBits = MVT::getSizeInBits(VT); 1626 1627 // fold (srl c1, c2) -> c1 >>u c2 1628 if (N0C && N1C) 1629 return DAG.getNode(ISD::SRL, VT, N0, N1); 1630 // fold (srl 0, x) -> 0 1631 if (N0C && N0C->isNullValue()) 1632 return N0; 1633 // fold (srl x, c >= size(x)) -> undef 1634 if (N1C && N1C->getValue() >= OpSizeInBits) 1635 return DAG.getNode(ISD::UNDEF, VT); 1636 // fold (srl x, 0) -> x 1637 if (N1C && N1C->isNullValue()) 1638 return N0; 1639 // if (srl x, c) is known to be zero, return 0 1640 if (N1C && TLI.MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits))) 1641 return DAG.getConstant(0, VT); 1642 // fold (srl (srl x, c1), c2) -> 0 or (srl x, c1+c2) 1643 if (N1C && N0.getOpcode() == ISD::SRL && 1644 N0.getOperand(1).getOpcode() == ISD::Constant) { 1645 uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1646 uint64_t c2 = N1C->getValue(); 1647 if (c1 + c2 > OpSizeInBits) 1648 return DAG.getConstant(0, VT); 1649 return DAG.getNode(ISD::SRL, VT, N0.getOperand(0), 1650 DAG.getConstant(c1 + c2, N1.getValueType())); 1651 } 1652 1653 // fold (srl (anyextend x), c) -> (anyextend (srl x, c)) 1654 if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) { 1655 // Shifting in all undef bits? 1656 MVT::ValueType SmallVT = N0.getOperand(0).getValueType(); 1657 if (N1C->getValue() >= MVT::getSizeInBits(SmallVT)) 1658 return DAG.getNode(ISD::UNDEF, VT); 1659 1660 SDOperand SmallShift = DAG.getNode(ISD::SRL, SmallVT, N0.getOperand(0), N1); 1661 AddToWorkList(SmallShift.Val); 1662 return DAG.getNode(ISD::ANY_EXTEND, VT, SmallShift); 1663 } 1664 1665 // fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit). 1666 if (N1C && N0.getOpcode() == ISD::CTLZ && 1667 N1C->getValue() == Log2_32(MVT::getSizeInBits(VT))) { 1668 uint64_t KnownZero, KnownOne, Mask = MVT::getIntVTBitMask(VT); 1669 TLI.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne); 1670 1671 // If any of the input bits are KnownOne, then the input couldn't be all 1672 // zeros, thus the result of the srl will always be zero. 1673 if (KnownOne) return DAG.getConstant(0, VT); 1674 1675 // If all of the bits input the to ctlz node are known to be zero, then 1676 // the result of the ctlz is "32" and the result of the shift is one. 1677 uint64_t UnknownBits = ~KnownZero & Mask; 1678 if (UnknownBits == 0) return DAG.getConstant(1, VT); 1679 1680 // Otherwise, check to see if there is exactly one bit input to the ctlz. 1681 if ((UnknownBits & (UnknownBits-1)) == 0) { 1682 // Okay, we know that only that the single bit specified by UnknownBits 1683 // could be set on input to the CTLZ node. If this bit is set, the SRL 1684 // will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair 1685 // to an SRL,XOR pair, which is likely to simplify more. 1686 unsigned ShAmt = CountTrailingZeros_64(UnknownBits); 1687 SDOperand Op = N0.getOperand(0); 1688 if (ShAmt) { 1689 Op = DAG.getNode(ISD::SRL, VT, Op, 1690 DAG.getConstant(ShAmt, TLI.getShiftAmountTy())); 1691 AddToWorkList(Op.Val); 1692 } 1693 return DAG.getNode(ISD::XOR, VT, Op, DAG.getConstant(1, VT)); 1694 } 1695 } 1696 1697 return SDOperand(); 1698} 1699 1700SDOperand DAGCombiner::visitCTLZ(SDNode *N) { 1701 SDOperand N0 = N->getOperand(0); 1702 MVT::ValueType VT = N->getValueType(0); 1703 1704 // fold (ctlz c1) -> c2 1705 if (isa<ConstantSDNode>(N0)) 1706 return DAG.getNode(ISD::CTLZ, VT, N0); 1707 return SDOperand(); 1708} 1709 1710SDOperand DAGCombiner::visitCTTZ(SDNode *N) { 1711 SDOperand N0 = N->getOperand(0); 1712 MVT::ValueType VT = N->getValueType(0); 1713 1714 // fold (cttz c1) -> c2 1715 if (isa<ConstantSDNode>(N0)) 1716 return DAG.getNode(ISD::CTTZ, VT, N0); 1717 return SDOperand(); 1718} 1719 1720SDOperand DAGCombiner::visitCTPOP(SDNode *N) { 1721 SDOperand N0 = N->getOperand(0); 1722 MVT::ValueType VT = N->getValueType(0); 1723 1724 // fold (ctpop c1) -> c2 1725 if (isa<ConstantSDNode>(N0)) 1726 return DAG.getNode(ISD::CTPOP, VT, N0); 1727 return SDOperand(); 1728} 1729 1730SDOperand DAGCombiner::visitSELECT(SDNode *N) { 1731 SDOperand N0 = N->getOperand(0); 1732 SDOperand N1 = N->getOperand(1); 1733 SDOperand N2 = N->getOperand(2); 1734 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1735 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1736 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2); 1737 MVT::ValueType VT = N->getValueType(0); 1738 1739 // fold select C, X, X -> X 1740 if (N1 == N2) 1741 return N1; 1742 // fold select true, X, Y -> X 1743 if (N0C && !N0C->isNullValue()) 1744 return N1; 1745 // fold select false, X, Y -> Y 1746 if (N0C && N0C->isNullValue()) 1747 return N2; 1748 // fold select C, 1, X -> C | X 1749 if (MVT::i1 == VT && N1C && N1C->getValue() == 1) 1750 return DAG.getNode(ISD::OR, VT, N0, N2); 1751 // fold select C, 0, X -> ~C & X 1752 // FIXME: this should check for C type == X type, not i1? 1753 if (MVT::i1 == VT && N1C && N1C->isNullValue()) { 1754 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT)); 1755 AddToWorkList(XORNode.Val); 1756 return DAG.getNode(ISD::AND, VT, XORNode, N2); 1757 } 1758 // fold select C, X, 1 -> ~C | X 1759 if (MVT::i1 == VT && N2C && N2C->getValue() == 1) { 1760 SDOperand XORNode = DAG.getNode(ISD::XOR, VT, N0, DAG.getConstant(1, VT)); 1761 AddToWorkList(XORNode.Val); 1762 return DAG.getNode(ISD::OR, VT, XORNode, N1); 1763 } 1764 // fold select C, X, 0 -> C & X 1765 // FIXME: this should check for C type == X type, not i1? 1766 if (MVT::i1 == VT && N2C && N2C->isNullValue()) 1767 return DAG.getNode(ISD::AND, VT, N0, N1); 1768 // fold X ? X : Y --> X ? 1 : Y --> X | Y 1769 if (MVT::i1 == VT && N0 == N1) 1770 return DAG.getNode(ISD::OR, VT, N0, N2); 1771 // fold X ? Y : X --> X ? Y : 0 --> X & Y 1772 if (MVT::i1 == VT && N0 == N2) 1773 return DAG.getNode(ISD::AND, VT, N0, N1); 1774 1775 // If we can fold this based on the true/false value, do so. 1776 if (SimplifySelectOps(N, N1, N2)) 1777 return SDOperand(N, 0); // Don't revisit N. 1778 1779 // fold selects based on a setcc into other things, such as min/max/abs 1780 if (N0.getOpcode() == ISD::SETCC) 1781 // FIXME: 1782 // Check against MVT::Other for SELECT_CC, which is a workaround for targets 1783 // having to say they don't support SELECT_CC on every type the DAG knows 1784 // about, since there is no way to mark an opcode illegal at all value types 1785 if (TLI.isOperationLegal(ISD::SELECT_CC, MVT::Other)) 1786 return DAG.getNode(ISD::SELECT_CC, VT, N0.getOperand(0), N0.getOperand(1), 1787 N1, N2, N0.getOperand(2)); 1788 else 1789 return SimplifySelect(N0, N1, N2); 1790 return SDOperand(); 1791} 1792 1793SDOperand DAGCombiner::visitSELECT_CC(SDNode *N) { 1794 SDOperand N0 = N->getOperand(0); 1795 SDOperand N1 = N->getOperand(1); 1796 SDOperand N2 = N->getOperand(2); 1797 SDOperand N3 = N->getOperand(3); 1798 SDOperand N4 = N->getOperand(4); 1799 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 1800 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 1801 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2); 1802 ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get(); 1803 1804 // fold select_cc lhs, rhs, x, x, cc -> x 1805 if (N2 == N3) 1806 return N2; 1807 1808 // Determine if the condition we're dealing with is constant 1809 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false); 1810 1811 if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val)) { 1812 if (SCCC->getValue()) 1813 return N2; // cond always true -> true val 1814 else 1815 return N3; // cond always false -> false val 1816 } 1817 1818 // Fold to a simpler select_cc 1819 if (SCC.Val && SCC.getOpcode() == ISD::SETCC) 1820 return DAG.getNode(ISD::SELECT_CC, N2.getValueType(), 1821 SCC.getOperand(0), SCC.getOperand(1), N2, N3, 1822 SCC.getOperand(2)); 1823 1824 // If we can fold this based on the true/false value, do so. 1825 if (SimplifySelectOps(N, N2, N3)) 1826 return SDOperand(N, 0); // Don't revisit N. 1827 1828 // fold select_cc into other things, such as min/max/abs 1829 return SimplifySelectCC(N0, N1, N2, N3, CC); 1830} 1831 1832SDOperand DAGCombiner::visitSETCC(SDNode *N) { 1833 return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1), 1834 cast<CondCodeSDNode>(N->getOperand(2))->get()); 1835} 1836 1837SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) { 1838 SDOperand N0 = N->getOperand(0); 1839 MVT::ValueType VT = N->getValueType(0); 1840 1841 // fold (sext c1) -> c1 1842 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0)) 1843 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0); 1844 1845 // fold (sext (sext x)) -> (sext x) 1846 // fold (sext (aext x)) -> (sext x) 1847 if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 1848 return DAG.getNode(ISD::SIGN_EXTEND, VT, N0.getOperand(0)); 1849 1850 // fold (sext (truncate x)) -> (sextinreg x). 1851 if (N0.getOpcode() == ISD::TRUNCATE && 1852 (!AfterLegalize || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, 1853 N0.getValueType()))) { 1854 SDOperand Op = N0.getOperand(0); 1855 if (Op.getValueType() < VT) { 1856 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op); 1857 } else if (Op.getValueType() > VT) { 1858 Op = DAG.getNode(ISD::TRUNCATE, VT, Op); 1859 } 1860 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, Op, 1861 DAG.getValueType(N0.getValueType())); 1862 } 1863 1864 // fold (sext (load x)) -> (sext (truncate (sextload x))) 1865 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() && 1866 (!AfterLegalize||TLI.isOperationLegal(ISD::SEXTLOAD, N0.getValueType()))){ 1867 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0), 1868 N0.getOperand(1), N0.getOperand(2), 1869 N0.getValueType()); 1870 CombineTo(N, ExtLoad); 1871 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 1872 ExtLoad.getValue(1)); 1873 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1874 } 1875 1876 // fold (sext (sextload x)) -> (sext (truncate (sextload x))) 1877 // fold (sext ( extload x)) -> (sext (truncate (sextload x))) 1878 if ((N0.getOpcode() == ISD::SEXTLOAD || N0.getOpcode() == ISD::EXTLOAD) && 1879 N0.hasOneUse()) { 1880 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT(); 1881 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0), 1882 N0.getOperand(1), N0.getOperand(2), EVT); 1883 CombineTo(N, ExtLoad); 1884 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 1885 ExtLoad.getValue(1)); 1886 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1887 } 1888 1889 return SDOperand(); 1890} 1891 1892SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) { 1893 SDOperand N0 = N->getOperand(0); 1894 MVT::ValueType VT = N->getValueType(0); 1895 1896 // fold (zext c1) -> c1 1897 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0)) 1898 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0); 1899 // fold (zext (zext x)) -> (zext x) 1900 // fold (zext (aext x)) -> (zext x) 1901 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) 1902 return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0)); 1903 1904 // fold (zext (truncate x)) -> (and x, mask) 1905 if (N0.getOpcode() == ISD::TRUNCATE && 1906 (!AfterLegalize || TLI.isOperationLegal(ISD::AND, VT))) { 1907 SDOperand Op = N0.getOperand(0); 1908 if (Op.getValueType() < VT) { 1909 Op = DAG.getNode(ISD::ANY_EXTEND, VT, Op); 1910 } else if (Op.getValueType() > VT) { 1911 Op = DAG.getNode(ISD::TRUNCATE, VT, Op); 1912 } 1913 return DAG.getZeroExtendInReg(Op, N0.getValueType()); 1914 } 1915 1916 // fold (zext (and (trunc x), cst)) -> (and x, cst). 1917 if (N0.getOpcode() == ISD::AND && 1918 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 1919 N0.getOperand(1).getOpcode() == ISD::Constant) { 1920 SDOperand X = N0.getOperand(0).getOperand(0); 1921 if (X.getValueType() < VT) { 1922 X = DAG.getNode(ISD::ANY_EXTEND, VT, X); 1923 } else if (X.getValueType() > VT) { 1924 X = DAG.getNode(ISD::TRUNCATE, VT, X); 1925 } 1926 uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1927 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT)); 1928 } 1929 1930 // fold (zext (load x)) -> (zext (truncate (zextload x))) 1931 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() && 1932 (!AfterLegalize||TLI.isOperationLegal(ISD::ZEXTLOAD, N0.getValueType()))){ 1933 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0), 1934 N0.getOperand(1), N0.getOperand(2), 1935 N0.getValueType()); 1936 CombineTo(N, ExtLoad); 1937 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 1938 ExtLoad.getValue(1)); 1939 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1940 } 1941 1942 // fold (zext (zextload x)) -> (zext (truncate (zextload x))) 1943 // fold (zext ( extload x)) -> (zext (truncate (zextload x))) 1944 if ((N0.getOpcode() == ISD::ZEXTLOAD || N0.getOpcode() == ISD::EXTLOAD) && 1945 N0.hasOneUse()) { 1946 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT(); 1947 SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0), 1948 N0.getOperand(1), N0.getOperand(2), EVT); 1949 CombineTo(N, ExtLoad); 1950 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 1951 ExtLoad.getValue(1)); 1952 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 1953 } 1954 return SDOperand(); 1955} 1956 1957SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) { 1958 SDOperand N0 = N->getOperand(0); 1959 MVT::ValueType VT = N->getValueType(0); 1960 1961 // fold (aext c1) -> c1 1962 if (isa<ConstantSDNode>(N0)) 1963 return DAG.getNode(ISD::ANY_EXTEND, VT, N0); 1964 // fold (aext (aext x)) -> (aext x) 1965 // fold (aext (zext x)) -> (zext x) 1966 // fold (aext (sext x)) -> (sext x) 1967 if (N0.getOpcode() == ISD::ANY_EXTEND || 1968 N0.getOpcode() == ISD::ZERO_EXTEND || 1969 N0.getOpcode() == ISD::SIGN_EXTEND) 1970 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0)); 1971 1972 // fold (aext (truncate x)) 1973 if (N0.getOpcode() == ISD::TRUNCATE) { 1974 SDOperand TruncOp = N0.getOperand(0); 1975 if (TruncOp.getValueType() == VT) 1976 return TruncOp; // x iff x size == zext size. 1977 if (TruncOp.getValueType() > VT) 1978 return DAG.getNode(ISD::TRUNCATE, VT, TruncOp); 1979 return DAG.getNode(ISD::ANY_EXTEND, VT, TruncOp); 1980 } 1981 1982 // fold (aext (and (trunc x), cst)) -> (and x, cst). 1983 if (N0.getOpcode() == ISD::AND && 1984 N0.getOperand(0).getOpcode() == ISD::TRUNCATE && 1985 N0.getOperand(1).getOpcode() == ISD::Constant) { 1986 SDOperand X = N0.getOperand(0).getOperand(0); 1987 if (X.getValueType() < VT) { 1988 X = DAG.getNode(ISD::ANY_EXTEND, VT, X); 1989 } else if (X.getValueType() > VT) { 1990 X = DAG.getNode(ISD::TRUNCATE, VT, X); 1991 } 1992 uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 1993 return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT)); 1994 } 1995 1996 // fold (aext (load x)) -> (aext (truncate (extload x))) 1997 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() && 1998 (!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) { 1999 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N0.getOperand(0), 2000 N0.getOperand(1), N0.getOperand(2), 2001 N0.getValueType()); 2002 CombineTo(N, ExtLoad); 2003 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 2004 ExtLoad.getValue(1)); 2005 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2006 } 2007 2008 // fold (aext (zextload x)) -> (aext (truncate (zextload x))) 2009 // fold (aext (sextload x)) -> (aext (truncate (sextload x))) 2010 // fold (aext ( extload x)) -> (aext (truncate (extload x))) 2011 if ((N0.getOpcode() == ISD::ZEXTLOAD || N0.getOpcode() == ISD::EXTLOAD || 2012 N0.getOpcode() == ISD::SEXTLOAD) && 2013 N0.hasOneUse()) { 2014 MVT::ValueType EVT = cast<VTSDNode>(N0.getOperand(3))->getVT(); 2015 SDOperand ExtLoad = DAG.getExtLoad(N0.getOpcode(), VT, N0.getOperand(0), 2016 N0.getOperand(1), N0.getOperand(2), EVT); 2017 CombineTo(N, ExtLoad); 2018 CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad), 2019 ExtLoad.getValue(1)); 2020 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2021 } 2022 return SDOperand(); 2023} 2024 2025 2026SDOperand DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) { 2027 SDOperand N0 = N->getOperand(0); 2028 SDOperand N1 = N->getOperand(1); 2029 MVT::ValueType VT = N->getValueType(0); 2030 MVT::ValueType EVT = cast<VTSDNode>(N1)->getVT(); 2031 unsigned EVTBits = MVT::getSizeInBits(EVT); 2032 2033 // fold (sext_in_reg c1) -> c1 2034 if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF) 2035 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0, N1); 2036 2037 // If the input is already sign extended, just drop the extension. 2038 if (TLI.ComputeNumSignBits(N0) >= MVT::getSizeInBits(VT)-EVTBits+1) 2039 return N0; 2040 2041 // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2 2042 if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && 2043 EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) { 2044 return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1); 2045 } 2046 2047 // fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is zero 2048 if (TLI.MaskedValueIsZero(N0, 1ULL << (EVTBits-1))) 2049 return DAG.getZeroExtendInReg(N0, EVT); 2050 2051 // fold (sext_in_reg (srl X, 24), i8) -> sra X, 24 2052 // fold (sext_in_reg (srl X, 23), i8) -> sra X, 23 iff possible. 2053 // We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above. 2054 if (N0.getOpcode() == ISD::SRL) { 2055 if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1))) 2056 if (ShAmt->getValue()+EVTBits <= MVT::getSizeInBits(VT)) { 2057 // We can turn this into an SRA iff the input to the SRL is already sign 2058 // extended enough. 2059 unsigned InSignBits = TLI.ComputeNumSignBits(N0.getOperand(0)); 2060 if (MVT::getSizeInBits(VT)-(ShAmt->getValue()+EVTBits) < InSignBits) 2061 return DAG.getNode(ISD::SRA, VT, N0.getOperand(0), N0.getOperand(1)); 2062 } 2063 } 2064 2065 // fold (sext_inreg (extload x)) -> (sextload x) 2066 if (N0.getOpcode() == ISD::EXTLOAD && 2067 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() && 2068 (!AfterLegalize || TLI.isOperationLegal(ISD::SEXTLOAD, EVT))) { 2069 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0), 2070 N0.getOperand(1), N0.getOperand(2), 2071 EVT); 2072 CombineTo(N, ExtLoad); 2073 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1)); 2074 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2075 } 2076 // fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use 2077 if (N0.getOpcode() == ISD::ZEXTLOAD && N0.hasOneUse() && 2078 EVT == cast<VTSDNode>(N0.getOperand(3))->getVT() && 2079 (!AfterLegalize || TLI.isOperationLegal(ISD::SEXTLOAD, EVT))) { 2080 SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0), 2081 N0.getOperand(1), N0.getOperand(2), 2082 EVT); 2083 CombineTo(N, ExtLoad); 2084 CombineTo(N0.Val, ExtLoad, ExtLoad.getValue(1)); 2085 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2086 } 2087 return SDOperand(); 2088} 2089 2090SDOperand DAGCombiner::visitTRUNCATE(SDNode *N) { 2091 SDOperand N0 = N->getOperand(0); 2092 MVT::ValueType VT = N->getValueType(0); 2093 2094 // noop truncate 2095 if (N0.getValueType() == N->getValueType(0)) 2096 return N0; 2097 // fold (truncate c1) -> c1 2098 if (isa<ConstantSDNode>(N0)) 2099 return DAG.getNode(ISD::TRUNCATE, VT, N0); 2100 // fold (truncate (truncate x)) -> (truncate x) 2101 if (N0.getOpcode() == ISD::TRUNCATE) 2102 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0)); 2103 // fold (truncate (ext x)) -> (ext x) or (truncate x) or x 2104 if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::SIGN_EXTEND|| 2105 N0.getOpcode() == ISD::ANY_EXTEND) { 2106 if (N0.getValueType() < VT) 2107 // if the source is smaller than the dest, we still need an extend 2108 return DAG.getNode(N0.getOpcode(), VT, N0.getOperand(0)); 2109 else if (N0.getValueType() > VT) 2110 // if the source is larger than the dest, than we just need the truncate 2111 return DAG.getNode(ISD::TRUNCATE, VT, N0.getOperand(0)); 2112 else 2113 // if the source and dest are the same type, we can drop both the extend 2114 // and the truncate 2115 return N0.getOperand(0); 2116 } 2117 // fold (truncate (load x)) -> (smaller load x) 2118 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) { 2119 assert(MVT::getSizeInBits(N0.getValueType()) > MVT::getSizeInBits(VT) && 2120 "Cannot truncate to larger type!"); 2121 MVT::ValueType PtrType = N0.getOperand(1).getValueType(); 2122 // For big endian targets, we need to add an offset to the pointer to load 2123 // the correct bytes. For little endian systems, we merely need to read 2124 // fewer bytes from the same pointer. 2125 uint64_t PtrOff = 2126 (MVT::getSizeInBits(N0.getValueType()) - MVT::getSizeInBits(VT)) / 8; 2127 SDOperand NewPtr = TLI.isLittleEndian() ? N0.getOperand(1) : 2128 DAG.getNode(ISD::ADD, PtrType, N0.getOperand(1), 2129 DAG.getConstant(PtrOff, PtrType)); 2130 AddToWorkList(NewPtr.Val); 2131 SDOperand Load = DAG.getLoad(VT, N0.getOperand(0), NewPtr,N0.getOperand(2)); 2132 AddToWorkList(N); 2133 CombineTo(N0.Val, Load, Load.getValue(1)); 2134 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2135 } 2136 return SDOperand(); 2137} 2138 2139SDOperand DAGCombiner::visitBIT_CONVERT(SDNode *N) { 2140 SDOperand N0 = N->getOperand(0); 2141 MVT::ValueType VT = N->getValueType(0); 2142 2143 // If the input is a constant, let getNode() fold it. 2144 if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) { 2145 SDOperand Res = DAG.getNode(ISD::BIT_CONVERT, VT, N0); 2146 if (Res.Val != N) return Res; 2147 } 2148 2149 if (N0.getOpcode() == ISD::BIT_CONVERT) // conv(conv(x,t1),t2) -> conv(x,t2) 2150 return DAG.getNode(ISD::BIT_CONVERT, VT, N0.getOperand(0)); 2151 2152 // fold (conv (load x)) -> (load (conv*)x) 2153 // FIXME: These xforms need to know that the resultant load doesn't need a 2154 // higher alignment than the original! 2155 if (0 && N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) { 2156 SDOperand Load = DAG.getLoad(VT, N0.getOperand(0), N0.getOperand(1), 2157 N0.getOperand(2)); 2158 AddToWorkList(N); 2159 CombineTo(N0.Val, DAG.getNode(ISD::BIT_CONVERT, N0.getValueType(), Load), 2160 Load.getValue(1)); 2161 return Load; 2162 } 2163 2164 return SDOperand(); 2165} 2166 2167SDOperand DAGCombiner::visitVBIT_CONVERT(SDNode *N) { 2168 SDOperand N0 = N->getOperand(0); 2169 MVT::ValueType VT = N->getValueType(0); 2170 2171 // If the input is a VBUILD_VECTOR with all constant elements, fold this now. 2172 // First check to see if this is all constant. 2173 if (N0.getOpcode() == ISD::VBUILD_VECTOR && N0.Val->hasOneUse() && 2174 VT == MVT::Vector) { 2175 bool isSimple = true; 2176 for (unsigned i = 0, e = N0.getNumOperands()-2; i != e; ++i) 2177 if (N0.getOperand(i).getOpcode() != ISD::UNDEF && 2178 N0.getOperand(i).getOpcode() != ISD::Constant && 2179 N0.getOperand(i).getOpcode() != ISD::ConstantFP) { 2180 isSimple = false; 2181 break; 2182 } 2183 2184 MVT::ValueType DestEltVT = cast<VTSDNode>(N->getOperand(2))->getVT(); 2185 if (isSimple && !MVT::isVector(DestEltVT)) { 2186 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(N0.Val, DestEltVT); 2187 } 2188 } 2189 2190 return SDOperand(); 2191} 2192 2193/// ConstantFoldVBIT_CONVERTofVBUILD_VECTOR - We know that BV is a vbuild_vector 2194/// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the 2195/// destination element value type. 2196SDOperand DAGCombiner:: 2197ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(SDNode *BV, MVT::ValueType DstEltVT) { 2198 MVT::ValueType SrcEltVT = BV->getOperand(0).getValueType(); 2199 2200 // If this is already the right type, we're done. 2201 if (SrcEltVT == DstEltVT) return SDOperand(BV, 0); 2202 2203 unsigned SrcBitSize = MVT::getSizeInBits(SrcEltVT); 2204 unsigned DstBitSize = MVT::getSizeInBits(DstEltVT); 2205 2206 // If this is a conversion of N elements of one type to N elements of another 2207 // type, convert each element. This handles FP<->INT cases. 2208 if (SrcBitSize == DstBitSize) { 2209 SmallVector<SDOperand, 8> Ops; 2210 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) { 2211 Ops.push_back(DAG.getNode(ISD::BIT_CONVERT, DstEltVT, BV->getOperand(i))); 2212 AddToWorkList(Ops.back().Val); 2213 } 2214 Ops.push_back(*(BV->op_end()-2)); // Add num elements. 2215 Ops.push_back(DAG.getValueType(DstEltVT)); 2216 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size()); 2217 } 2218 2219 // Otherwise, we're growing or shrinking the elements. To avoid having to 2220 // handle annoying details of growing/shrinking FP values, we convert them to 2221 // int first. 2222 if (MVT::isFloatingPoint(SrcEltVT)) { 2223 // Convert the input float vector to a int vector where the elements are the 2224 // same sizes. 2225 assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!"); 2226 MVT::ValueType IntVT = SrcEltVT == MVT::f32 ? MVT::i32 : MVT::i64; 2227 BV = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, IntVT).Val; 2228 SrcEltVT = IntVT; 2229 } 2230 2231 // Now we know the input is an integer vector. If the output is a FP type, 2232 // convert to integer first, then to FP of the right size. 2233 if (MVT::isFloatingPoint(DstEltVT)) { 2234 assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!"); 2235 MVT::ValueType TmpVT = DstEltVT == MVT::f32 ? MVT::i32 : MVT::i64; 2236 SDNode *Tmp = ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(BV, TmpVT).Val; 2237 2238 // Next, convert to FP elements of the same size. 2239 return ConstantFoldVBIT_CONVERTofVBUILD_VECTOR(Tmp, DstEltVT); 2240 } 2241 2242 // Okay, we know the src/dst types are both integers of differing types. 2243 // Handling growing first. 2244 assert(MVT::isInteger(SrcEltVT) && MVT::isInteger(DstEltVT)); 2245 if (SrcBitSize < DstBitSize) { 2246 unsigned NumInputsPerOutput = DstBitSize/SrcBitSize; 2247 2248 SmallVector<SDOperand, 8> Ops; 2249 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; 2250 i += NumInputsPerOutput) { 2251 bool isLE = TLI.isLittleEndian(); 2252 uint64_t NewBits = 0; 2253 bool EltIsUndef = true; 2254 for (unsigned j = 0; j != NumInputsPerOutput; ++j) { 2255 // Shift the previously computed bits over. 2256 NewBits <<= SrcBitSize; 2257 SDOperand Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j)); 2258 if (Op.getOpcode() == ISD::UNDEF) continue; 2259 EltIsUndef = false; 2260 2261 NewBits |= cast<ConstantSDNode>(Op)->getValue(); 2262 } 2263 2264 if (EltIsUndef) 2265 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT)); 2266 else 2267 Ops.push_back(DAG.getConstant(NewBits, DstEltVT)); 2268 } 2269 2270 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements. 2271 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size. 2272 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size()); 2273 } 2274 2275 // Finally, this must be the case where we are shrinking elements: each input 2276 // turns into multiple outputs. 2277 unsigned NumOutputsPerInput = SrcBitSize/DstBitSize; 2278 SmallVector<SDOperand, 8> Ops; 2279 for (unsigned i = 0, e = BV->getNumOperands()-2; i != e; ++i) { 2280 if (BV->getOperand(i).getOpcode() == ISD::UNDEF) { 2281 for (unsigned j = 0; j != NumOutputsPerInput; ++j) 2282 Ops.push_back(DAG.getNode(ISD::UNDEF, DstEltVT)); 2283 continue; 2284 } 2285 uint64_t OpVal = cast<ConstantSDNode>(BV->getOperand(i))->getValue(); 2286 2287 for (unsigned j = 0; j != NumOutputsPerInput; ++j) { 2288 unsigned ThisVal = OpVal & ((1ULL << DstBitSize)-1); 2289 OpVal >>= DstBitSize; 2290 Ops.push_back(DAG.getConstant(ThisVal, DstEltVT)); 2291 } 2292 2293 // For big endian targets, swap the order of the pieces of each element. 2294 if (!TLI.isLittleEndian()) 2295 std::reverse(Ops.end()-NumOutputsPerInput, Ops.end()); 2296 } 2297 Ops.push_back(DAG.getConstant(Ops.size(), MVT::i32)); // Add num elements. 2298 Ops.push_back(DAG.getValueType(DstEltVT)); // Add element size. 2299 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size()); 2300} 2301 2302 2303 2304SDOperand DAGCombiner::visitFADD(SDNode *N) { 2305 SDOperand N0 = N->getOperand(0); 2306 SDOperand N1 = N->getOperand(1); 2307 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2308 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2309 MVT::ValueType VT = N->getValueType(0); 2310 2311 // fold (fadd c1, c2) -> c1+c2 2312 if (N0CFP && N1CFP) 2313 return DAG.getNode(ISD::FADD, VT, N0, N1); 2314 // canonicalize constant to RHS 2315 if (N0CFP && !N1CFP) 2316 return DAG.getNode(ISD::FADD, VT, N1, N0); 2317 // fold (A + (-B)) -> A-B 2318 if (N1.getOpcode() == ISD::FNEG) 2319 return DAG.getNode(ISD::FSUB, VT, N0, N1.getOperand(0)); 2320 // fold ((-A) + B) -> B-A 2321 if (N0.getOpcode() == ISD::FNEG) 2322 return DAG.getNode(ISD::FSUB, VT, N1, N0.getOperand(0)); 2323 return SDOperand(); 2324} 2325 2326SDOperand DAGCombiner::visitFSUB(SDNode *N) { 2327 SDOperand N0 = N->getOperand(0); 2328 SDOperand N1 = N->getOperand(1); 2329 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2330 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2331 MVT::ValueType VT = N->getValueType(0); 2332 2333 // fold (fsub c1, c2) -> c1-c2 2334 if (N0CFP && N1CFP) 2335 return DAG.getNode(ISD::FSUB, VT, N0, N1); 2336 // fold (A-(-B)) -> A+B 2337 if (N1.getOpcode() == ISD::FNEG) 2338 return DAG.getNode(ISD::FADD, VT, N0, N1.getOperand(0)); 2339 return SDOperand(); 2340} 2341 2342SDOperand DAGCombiner::visitFMUL(SDNode *N) { 2343 SDOperand N0 = N->getOperand(0); 2344 SDOperand N1 = N->getOperand(1); 2345 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2346 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2347 MVT::ValueType VT = N->getValueType(0); 2348 2349 // fold (fmul c1, c2) -> c1*c2 2350 if (N0CFP && N1CFP) 2351 return DAG.getNode(ISD::FMUL, VT, N0, N1); 2352 // canonicalize constant to RHS 2353 if (N0CFP && !N1CFP) 2354 return DAG.getNode(ISD::FMUL, VT, N1, N0); 2355 // fold (fmul X, 2.0) -> (fadd X, X) 2356 if (N1CFP && N1CFP->isExactlyValue(+2.0)) 2357 return DAG.getNode(ISD::FADD, VT, N0, N0); 2358 return SDOperand(); 2359} 2360 2361SDOperand DAGCombiner::visitFDIV(SDNode *N) { 2362 SDOperand N0 = N->getOperand(0); 2363 SDOperand N1 = N->getOperand(1); 2364 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2365 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2366 MVT::ValueType VT = N->getValueType(0); 2367 2368 // fold (fdiv c1, c2) -> c1/c2 2369 if (N0CFP && N1CFP) 2370 return DAG.getNode(ISD::FDIV, VT, N0, N1); 2371 return SDOperand(); 2372} 2373 2374SDOperand DAGCombiner::visitFREM(SDNode *N) { 2375 SDOperand N0 = N->getOperand(0); 2376 SDOperand N1 = N->getOperand(1); 2377 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2378 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2379 MVT::ValueType VT = N->getValueType(0); 2380 2381 // fold (frem c1, c2) -> fmod(c1,c2) 2382 if (N0CFP && N1CFP) 2383 return DAG.getNode(ISD::FREM, VT, N0, N1); 2384 return SDOperand(); 2385} 2386 2387SDOperand DAGCombiner::visitFCOPYSIGN(SDNode *N) { 2388 SDOperand N0 = N->getOperand(0); 2389 SDOperand N1 = N->getOperand(1); 2390 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2391 ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1); 2392 MVT::ValueType VT = N->getValueType(0); 2393 2394 if (N0CFP && N1CFP) // Constant fold 2395 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1); 2396 2397 if (N1CFP) { 2398 // copysign(x, c1) -> fabs(x) iff ispos(c1) 2399 // copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1) 2400 union { 2401 double d; 2402 int64_t i; 2403 } u; 2404 u.d = N1CFP->getValue(); 2405 if (u.i >= 0) 2406 return DAG.getNode(ISD::FABS, VT, N0); 2407 else 2408 return DAG.getNode(ISD::FNEG, VT, DAG.getNode(ISD::FABS, VT, N0)); 2409 } 2410 2411 // copysign(fabs(x), y) -> copysign(x, y) 2412 // copysign(fneg(x), y) -> copysign(x, y) 2413 // copysign(copysign(x,z), y) -> copysign(x, y) 2414 if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG || 2415 N0.getOpcode() == ISD::FCOPYSIGN) 2416 return DAG.getNode(ISD::FCOPYSIGN, VT, N0.getOperand(0), N1); 2417 2418 // copysign(x, abs(y)) -> abs(x) 2419 if (N1.getOpcode() == ISD::FABS) 2420 return DAG.getNode(ISD::FABS, VT, N0); 2421 2422 // copysign(x, copysign(y,z)) -> copysign(x, z) 2423 if (N1.getOpcode() == ISD::FCOPYSIGN) 2424 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(1)); 2425 2426 // copysign(x, fp_extend(y)) -> copysign(x, y) 2427 // copysign(x, fp_round(y)) -> copysign(x, y) 2428 if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND) 2429 return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(0)); 2430 2431 return SDOperand(); 2432} 2433 2434 2435 2436SDOperand DAGCombiner::visitSINT_TO_FP(SDNode *N) { 2437 SDOperand N0 = N->getOperand(0); 2438 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2439 MVT::ValueType VT = N->getValueType(0); 2440 2441 // fold (sint_to_fp c1) -> c1fp 2442 if (N0C) 2443 return DAG.getNode(ISD::SINT_TO_FP, VT, N0); 2444 return SDOperand(); 2445} 2446 2447SDOperand DAGCombiner::visitUINT_TO_FP(SDNode *N) { 2448 SDOperand N0 = N->getOperand(0); 2449 ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0); 2450 MVT::ValueType VT = N->getValueType(0); 2451 2452 // fold (uint_to_fp c1) -> c1fp 2453 if (N0C) 2454 return DAG.getNode(ISD::UINT_TO_FP, VT, N0); 2455 return SDOperand(); 2456} 2457 2458SDOperand DAGCombiner::visitFP_TO_SINT(SDNode *N) { 2459 SDOperand N0 = N->getOperand(0); 2460 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2461 MVT::ValueType VT = N->getValueType(0); 2462 2463 // fold (fp_to_sint c1fp) -> c1 2464 if (N0CFP) 2465 return DAG.getNode(ISD::FP_TO_SINT, VT, N0); 2466 return SDOperand(); 2467} 2468 2469SDOperand DAGCombiner::visitFP_TO_UINT(SDNode *N) { 2470 SDOperand N0 = N->getOperand(0); 2471 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2472 MVT::ValueType VT = N->getValueType(0); 2473 2474 // fold (fp_to_uint c1fp) -> c1 2475 if (N0CFP) 2476 return DAG.getNode(ISD::FP_TO_UINT, VT, N0); 2477 return SDOperand(); 2478} 2479 2480SDOperand DAGCombiner::visitFP_ROUND(SDNode *N) { 2481 SDOperand N0 = N->getOperand(0); 2482 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2483 MVT::ValueType VT = N->getValueType(0); 2484 2485 // fold (fp_round c1fp) -> c1fp 2486 if (N0CFP) 2487 return DAG.getNode(ISD::FP_ROUND, VT, N0); 2488 2489 // fold (fp_round (fp_extend x)) -> x 2490 if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType()) 2491 return N0.getOperand(0); 2492 2493 // fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y) 2494 if (N0.getOpcode() == ISD::FCOPYSIGN && N0.Val->hasOneUse()) { 2495 SDOperand Tmp = DAG.getNode(ISD::FP_ROUND, VT, N0.getOperand(0)); 2496 AddToWorkList(Tmp.Val); 2497 return DAG.getNode(ISD::FCOPYSIGN, VT, Tmp, N0.getOperand(1)); 2498 } 2499 2500 return SDOperand(); 2501} 2502 2503SDOperand DAGCombiner::visitFP_ROUND_INREG(SDNode *N) { 2504 SDOperand N0 = N->getOperand(0); 2505 MVT::ValueType VT = N->getValueType(0); 2506 MVT::ValueType EVT = cast<VTSDNode>(N->getOperand(1))->getVT(); 2507 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2508 2509 // fold (fp_round_inreg c1fp) -> c1fp 2510 if (N0CFP) { 2511 SDOperand Round = DAG.getConstantFP(N0CFP->getValue(), EVT); 2512 return DAG.getNode(ISD::FP_EXTEND, VT, Round); 2513 } 2514 return SDOperand(); 2515} 2516 2517SDOperand DAGCombiner::visitFP_EXTEND(SDNode *N) { 2518 SDOperand N0 = N->getOperand(0); 2519 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2520 MVT::ValueType VT = N->getValueType(0); 2521 2522 // fold (fp_extend c1fp) -> c1fp 2523 if (N0CFP) 2524 return DAG.getNode(ISD::FP_EXTEND, VT, N0); 2525 2526 // fold (fpext (load x)) -> (fpext (fpround (extload x))) 2527 if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() && 2528 (!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) { 2529 SDOperand ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, VT, N0.getOperand(0), 2530 N0.getOperand(1), N0.getOperand(2), 2531 N0.getValueType()); 2532 CombineTo(N, ExtLoad); 2533 CombineTo(N0.Val, DAG.getNode(ISD::FP_ROUND, N0.getValueType(), ExtLoad), 2534 ExtLoad.getValue(1)); 2535 return SDOperand(N, 0); // Return N so it doesn't get rechecked! 2536 } 2537 2538 2539 return SDOperand(); 2540} 2541 2542SDOperand DAGCombiner::visitFNEG(SDNode *N) { 2543 SDOperand N0 = N->getOperand(0); 2544 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2545 MVT::ValueType VT = N->getValueType(0); 2546 2547 // fold (fneg c1) -> -c1 2548 if (N0CFP) 2549 return DAG.getNode(ISD::FNEG, VT, N0); 2550 // fold (fneg (sub x, y)) -> (sub y, x) 2551 if (N0.getOpcode() == ISD::SUB) 2552 return DAG.getNode(ISD::SUB, VT, N0.getOperand(1), N0.getOperand(0)); 2553 // fold (fneg (fneg x)) -> x 2554 if (N0.getOpcode() == ISD::FNEG) 2555 return N0.getOperand(0); 2556 return SDOperand(); 2557} 2558 2559SDOperand DAGCombiner::visitFABS(SDNode *N) { 2560 SDOperand N0 = N->getOperand(0); 2561 ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0); 2562 MVT::ValueType VT = N->getValueType(0); 2563 2564 // fold (fabs c1) -> fabs(c1) 2565 if (N0CFP) 2566 return DAG.getNode(ISD::FABS, VT, N0); 2567 // fold (fabs (fabs x)) -> (fabs x) 2568 if (N0.getOpcode() == ISD::FABS) 2569 return N->getOperand(0); 2570 // fold (fabs (fneg x)) -> (fabs x) 2571 // fold (fabs (fcopysign x, y)) -> (fabs x) 2572 if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN) 2573 return DAG.getNode(ISD::FABS, VT, N0.getOperand(0)); 2574 2575 return SDOperand(); 2576} 2577 2578SDOperand DAGCombiner::visitBRCOND(SDNode *N) { 2579 SDOperand Chain = N->getOperand(0); 2580 SDOperand N1 = N->getOperand(1); 2581 SDOperand N2 = N->getOperand(2); 2582 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); 2583 2584 // never taken branch, fold to chain 2585 if (N1C && N1C->isNullValue()) 2586 return Chain; 2587 // unconditional branch 2588 if (N1C && N1C->getValue() == 1) 2589 return DAG.getNode(ISD::BR, MVT::Other, Chain, N2); 2590 // fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal 2591 // on the target. 2592 if (N1.getOpcode() == ISD::SETCC && 2593 TLI.isOperationLegal(ISD::BR_CC, MVT::Other)) { 2594 return DAG.getNode(ISD::BR_CC, MVT::Other, Chain, N1.getOperand(2), 2595 N1.getOperand(0), N1.getOperand(1), N2); 2596 } 2597 return SDOperand(); 2598} 2599 2600// Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB. 2601// 2602SDOperand DAGCombiner::visitBR_CC(SDNode *N) { 2603 CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1)); 2604 SDOperand CondLHS = N->getOperand(2), CondRHS = N->getOperand(3); 2605 2606 // Use SimplifySetCC to simplify SETCC's. 2607 SDOperand Simp = SimplifySetCC(MVT::i1, CondLHS, CondRHS, CC->get(), false); 2608 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(Simp.Val); 2609 2610 // fold br_cc true, dest -> br dest (unconditional branch) 2611 if (SCCC && SCCC->getValue()) 2612 return DAG.getNode(ISD::BR, MVT::Other, N->getOperand(0), 2613 N->getOperand(4)); 2614 // fold br_cc false, dest -> unconditional fall through 2615 if (SCCC && SCCC->isNullValue()) 2616 return N->getOperand(0); 2617 // fold to a simpler setcc 2618 if (Simp.Val && Simp.getOpcode() == ISD::SETCC) 2619 return DAG.getNode(ISD::BR_CC, MVT::Other, N->getOperand(0), 2620 Simp.getOperand(2), Simp.getOperand(0), 2621 Simp.getOperand(1), N->getOperand(4)); 2622 return SDOperand(); 2623} 2624 2625SDOperand DAGCombiner::visitLOAD(SDNode *N) { 2626 SDOperand Chain = N->getOperand(0); 2627 SDOperand Ptr = N->getOperand(1); 2628 SDOperand SrcValue = N->getOperand(2); 2629 2630 // If there are no uses of the loaded value, change uses of the chain value 2631 // into uses of the chain input (i.e. delete the dead load). 2632 if (N->hasNUsesOfValue(0, 0)) 2633 return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain); 2634 2635 // If this load is directly stored, replace the load value with the stored 2636 // value. 2637 // TODO: Handle store large -> read small portion. 2638 // TODO: Handle TRUNCSTORE/EXTLOAD 2639 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr && 2640 Chain.getOperand(1).getValueType() == N->getValueType(0)) 2641 return CombineTo(N, Chain.getOperand(1), Chain); 2642 2643 if (CombinerAA) { 2644 // Walk up chain skipping non-aliasing memory nodes. 2645 SDOperand BetterChain = FindBetterChain(N, Chain); 2646 2647 // If the there is a better chain. 2648 if (Chain != BetterChain) { 2649 // Replace the chain to void dependency. 2650 SDOperand ReplLoad = DAG.getLoad(N->getValueType(0), BetterChain, Ptr, 2651 SrcValue); 2652 2653 // Replace uses with token. 2654 CombineTo(N, ReplLoad.getValue(0), ReplLoad.getValue(1)); 2655 2656 // Old chain needs to be cleaned up. 2657 AddToWorkList(Chain.Val); 2658 2659 // Don't recombine on token. 2660 return SDOperand(N, 0); 2661 } 2662 } 2663 2664 return SDOperand(); 2665} 2666 2667/// visitXEXTLOAD - Handle EXTLOAD/ZEXTLOAD/SEXTLOAD. 2668SDOperand DAGCombiner::visitXEXTLOAD(SDNode *N) { 2669 SDOperand Chain = N->getOperand(0); 2670 SDOperand Ptr = N->getOperand(1); 2671 SDOperand SrcValue = N->getOperand(2); 2672 SDOperand EVT = N->getOperand(3); 2673 2674 // If there are no uses of the loaded value, change uses of the chain value 2675 // into uses of the chain input (i.e. delete the dead load). 2676 if (N->hasNUsesOfValue(0, 0)) 2677 return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain); 2678 2679 return SDOperand(); 2680} 2681 2682SDOperand DAGCombiner::visitSTORE(SDNode *N) { 2683 SDOperand Chain = N->getOperand(0); 2684 SDOperand Value = N->getOperand(1); 2685 SDOperand Ptr = N->getOperand(2); 2686 SDOperand SrcValue = N->getOperand(3); 2687 2688 // If this is a store that kills a previous store, remove the previous store. 2689 if (Chain.getOpcode() == ISD::STORE && Chain.getOperand(2) == Ptr && 2690 Chain.Val->hasOneUse() /* Avoid introducing DAG cycles */ && 2691 // Make sure that these stores are the same value type: 2692 // FIXME: we really care that the second store is >= size of the first. 2693 Value.getValueType() == Chain.getOperand(1).getValueType()) { 2694 // Create a new store of Value that replaces both stores. 2695 SDNode *PrevStore = Chain.Val; 2696 if (PrevStore->getOperand(1) == Value) // Same value multiply stored. 2697 return Chain; 2698 SDOperand NewStore = DAG.getNode(ISD::STORE, MVT::Other, 2699 PrevStore->getOperand(0), Value, Ptr, 2700 SrcValue); 2701 CombineTo(N, NewStore); // Nuke this store. 2702 CombineTo(PrevStore, NewStore); // Nuke the previous store. 2703 return SDOperand(N, 0); 2704 } 2705 2706 // If this is a store of a bit convert, store the input value. 2707 // FIXME: This needs to know that the resultant store does not need a 2708 // higher alignment than the original. 2709 if (Value.getOpcode() == ISD::BIT_CONVERT) { 2710 return DAG.getNode(ISD::STORE, MVT::Other, Chain, Value.getOperand(0), 2711 Ptr, SrcValue); 2712 } 2713 2714 if (CombinerAA) { 2715 // Walk up chain skipping non-aliasing memory nodes. 2716 SDOperand BetterChain = FindBetterChain(N, Chain); 2717 2718 // If the there is a better chain. 2719 if (Chain != BetterChain) { 2720 // Replace the chain to void dependency. 2721 SDOperand ReplStore = DAG.getNode(ISD::STORE, MVT::Other, 2722 BetterChain, Value, Ptr, 2723 SrcValue); 2724 // Create token to keep both nodes around. 2725 SDOperand Token = DAG.getNode(ISD::TokenFactor, MVT::Other, 2726 Chain, ReplStore); 2727 2728 // Make sure we merge token factors. 2729 AddUsersToWorkList(N); 2730 2731 // Old chain needs to be cleaned up. 2732 AddToWorkList(Chain.Val); 2733 2734 return Token; 2735 } 2736 } 2737 2738 return SDOperand(); 2739} 2740 2741SDOperand DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { 2742 SDOperand InVec = N->getOperand(0); 2743 SDOperand InVal = N->getOperand(1); 2744 SDOperand EltNo = N->getOperand(2); 2745 2746 // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new 2747 // vector with the inserted element. 2748 if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) { 2749 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue(); 2750 SmallVector<SDOperand, 8> Ops(InVec.Val->op_begin(), InVec.Val->op_end()); 2751 if (Elt < Ops.size()) 2752 Ops[Elt] = InVal; 2753 return DAG.getNode(ISD::BUILD_VECTOR, InVec.getValueType(), 2754 &Ops[0], Ops.size()); 2755 } 2756 2757 return SDOperand(); 2758} 2759 2760SDOperand DAGCombiner::visitVINSERT_VECTOR_ELT(SDNode *N) { 2761 SDOperand InVec = N->getOperand(0); 2762 SDOperand InVal = N->getOperand(1); 2763 SDOperand EltNo = N->getOperand(2); 2764 SDOperand NumElts = N->getOperand(3); 2765 SDOperand EltType = N->getOperand(4); 2766 2767 // If the invec is a VBUILD_VECTOR and if EltNo is a constant, build a new 2768 // vector with the inserted element. 2769 if (InVec.getOpcode() == ISD::VBUILD_VECTOR && isa<ConstantSDNode>(EltNo)) { 2770 unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue(); 2771 SmallVector<SDOperand, 8> Ops(InVec.Val->op_begin(), InVec.Val->op_end()); 2772 if (Elt < Ops.size()-2) 2773 Ops[Elt] = InVal; 2774 return DAG.getNode(ISD::VBUILD_VECTOR, InVec.getValueType(), 2775 &Ops[0], Ops.size()); 2776 } 2777 2778 return SDOperand(); 2779} 2780 2781SDOperand DAGCombiner::visitVBUILD_VECTOR(SDNode *N) { 2782 unsigned NumInScalars = N->getNumOperands()-2; 2783 SDOperand NumElts = N->getOperand(NumInScalars); 2784 SDOperand EltType = N->getOperand(NumInScalars+1); 2785 2786 // Check to see if this is a VBUILD_VECTOR of a bunch of VEXTRACT_VECTOR_ELT 2787 // operations. If so, and if the EXTRACT_ELT vector inputs come from at most 2788 // two distinct vectors, turn this into a shuffle node. 2789 SDOperand VecIn1, VecIn2; 2790 for (unsigned i = 0; i != NumInScalars; ++i) { 2791 // Ignore undef inputs. 2792 if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue; 2793 2794 // If this input is something other than a VEXTRACT_VECTOR_ELT with a 2795 // constant index, bail out. 2796 if (N->getOperand(i).getOpcode() != ISD::VEXTRACT_VECTOR_ELT || 2797 !isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) { 2798 VecIn1 = VecIn2 = SDOperand(0, 0); 2799 break; 2800 } 2801 2802 // If the input vector type disagrees with the result of the vbuild_vector, 2803 // we can't make a shuffle. 2804 SDOperand ExtractedFromVec = N->getOperand(i).getOperand(0); 2805 if (*(ExtractedFromVec.Val->op_end()-2) != NumElts || 2806 *(ExtractedFromVec.Val->op_end()-1) != EltType) { 2807 VecIn1 = VecIn2 = SDOperand(0, 0); 2808 break; 2809 } 2810 2811 // Otherwise, remember this. We allow up to two distinct input vectors. 2812 if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2) 2813 continue; 2814 2815 if (VecIn1.Val == 0) { 2816 VecIn1 = ExtractedFromVec; 2817 } else if (VecIn2.Val == 0) { 2818 VecIn2 = ExtractedFromVec; 2819 } else { 2820 // Too many inputs. 2821 VecIn1 = VecIn2 = SDOperand(0, 0); 2822 break; 2823 } 2824 } 2825 2826 // If everything is good, we can make a shuffle operation. 2827 if (VecIn1.Val) { 2828 SmallVector<SDOperand, 8> BuildVecIndices; 2829 for (unsigned i = 0; i != NumInScalars; ++i) { 2830 if (N->getOperand(i).getOpcode() == ISD::UNDEF) { 2831 BuildVecIndices.push_back(DAG.getNode(ISD::UNDEF, MVT::i32)); 2832 continue; 2833 } 2834 2835 SDOperand Extract = N->getOperand(i); 2836 2837 // If extracting from the first vector, just use the index directly. 2838 if (Extract.getOperand(0) == VecIn1) { 2839 BuildVecIndices.push_back(Extract.getOperand(1)); 2840 continue; 2841 } 2842 2843 // Otherwise, use InIdx + VecSize 2844 unsigned Idx = cast<ConstantSDNode>(Extract.getOperand(1))->getValue(); 2845 BuildVecIndices.push_back(DAG.getConstant(Idx+NumInScalars, MVT::i32)); 2846 } 2847 2848 // Add count and size info. 2849 BuildVecIndices.push_back(NumElts); 2850 BuildVecIndices.push_back(DAG.getValueType(MVT::i32)); 2851 2852 // Return the new VVECTOR_SHUFFLE node. 2853 SDOperand Ops[5]; 2854 Ops[0] = VecIn1; 2855 if (VecIn2.Val) { 2856 Ops[1] = VecIn2; 2857 } else { 2858 // Use an undef vbuild_vector as input for the second operand. 2859 std::vector<SDOperand> UnOps(NumInScalars, 2860 DAG.getNode(ISD::UNDEF, 2861 cast<VTSDNode>(EltType)->getVT())); 2862 UnOps.push_back(NumElts); 2863 UnOps.push_back(EltType); 2864 Ops[1] = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 2865 &UnOps[0], UnOps.size()); 2866 AddToWorkList(Ops[1].Val); 2867 } 2868 Ops[2] = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 2869 &BuildVecIndices[0], BuildVecIndices.size()); 2870 Ops[3] = NumElts; 2871 Ops[4] = EltType; 2872 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, Ops, 5); 2873 } 2874 2875 return SDOperand(); 2876} 2877 2878SDOperand DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { 2879 SDOperand ShufMask = N->getOperand(2); 2880 unsigned NumElts = ShufMask.getNumOperands(); 2881 2882 // If the shuffle mask is an identity operation on the LHS, return the LHS. 2883 bool isIdentity = true; 2884 for (unsigned i = 0; i != NumElts; ++i) { 2885 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 2886 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) { 2887 isIdentity = false; 2888 break; 2889 } 2890 } 2891 if (isIdentity) return N->getOperand(0); 2892 2893 // If the shuffle mask is an identity operation on the RHS, return the RHS. 2894 isIdentity = true; 2895 for (unsigned i = 0; i != NumElts; ++i) { 2896 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 2897 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) { 2898 isIdentity = false; 2899 break; 2900 } 2901 } 2902 if (isIdentity) return N->getOperand(1); 2903 2904 // Check if the shuffle is a unary shuffle, i.e. one of the vectors is not 2905 // needed at all. 2906 bool isUnary = true; 2907 bool isSplat = true; 2908 int VecNum = -1; 2909 unsigned BaseIdx = 0; 2910 for (unsigned i = 0; i != NumElts; ++i) 2911 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) { 2912 unsigned Idx = cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue(); 2913 int V = (Idx < NumElts) ? 0 : 1; 2914 if (VecNum == -1) { 2915 VecNum = V; 2916 BaseIdx = Idx; 2917 } else { 2918 if (BaseIdx != Idx) 2919 isSplat = false; 2920 if (VecNum != V) { 2921 isUnary = false; 2922 break; 2923 } 2924 } 2925 } 2926 2927 SDOperand N0 = N->getOperand(0); 2928 SDOperand N1 = N->getOperand(1); 2929 // Normalize unary shuffle so the RHS is undef. 2930 if (isUnary && VecNum == 1) 2931 std::swap(N0, N1); 2932 2933 // If it is a splat, check if the argument vector is a build_vector with 2934 // all scalar elements the same. 2935 if (isSplat) { 2936 SDNode *V = N0.Val; 2937 if (V->getOpcode() == ISD::BIT_CONVERT) 2938 V = V->getOperand(0).Val; 2939 if (V->getOpcode() == ISD::BUILD_VECTOR) { 2940 unsigned NumElems = V->getNumOperands()-2; 2941 if (NumElems > BaseIdx) { 2942 SDOperand Base; 2943 bool AllSame = true; 2944 for (unsigned i = 0; i != NumElems; ++i) { 2945 if (V->getOperand(i).getOpcode() != ISD::UNDEF) { 2946 Base = V->getOperand(i); 2947 break; 2948 } 2949 } 2950 // Splat of <u, u, u, u>, return <u, u, u, u> 2951 if (!Base.Val) 2952 return N0; 2953 for (unsigned i = 0; i != NumElems; ++i) { 2954 if (V->getOperand(i).getOpcode() != ISD::UNDEF && 2955 V->getOperand(i) != Base) { 2956 AllSame = false; 2957 break; 2958 } 2959 } 2960 // Splat of <x, x, x, x>, return <x, x, x, x> 2961 if (AllSame) 2962 return N0; 2963 } 2964 } 2965 } 2966 2967 // If it is a unary or the LHS and the RHS are the same node, turn the RHS 2968 // into an undef. 2969 if (isUnary || N0 == N1) { 2970 if (N0.getOpcode() == ISD::UNDEF) 2971 return DAG.getNode(ISD::UNDEF, N->getValueType(0)); 2972 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the 2973 // first operand. 2974 SmallVector<SDOperand, 8> MappedOps; 2975 for (unsigned i = 0, e = ShufMask.getNumOperands(); i != e; ++i) { 2976 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF || 2977 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) { 2978 MappedOps.push_back(ShufMask.getOperand(i)); 2979 } else { 2980 unsigned NewIdx = 2981 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts; 2982 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32)); 2983 } 2984 } 2985 ShufMask = DAG.getNode(ISD::BUILD_VECTOR, ShufMask.getValueType(), 2986 &MappedOps[0], MappedOps.size()); 2987 AddToWorkList(ShufMask.Val); 2988 return DAG.getNode(ISD::VECTOR_SHUFFLE, N->getValueType(0), 2989 N0, 2990 DAG.getNode(ISD::UNDEF, N->getValueType(0)), 2991 ShufMask); 2992 } 2993 2994 return SDOperand(); 2995} 2996 2997SDOperand DAGCombiner::visitVVECTOR_SHUFFLE(SDNode *N) { 2998 SDOperand ShufMask = N->getOperand(2); 2999 unsigned NumElts = ShufMask.getNumOperands()-2; 3000 3001 // If the shuffle mask is an identity operation on the LHS, return the LHS. 3002 bool isIdentity = true; 3003 for (unsigned i = 0; i != NumElts; ++i) { 3004 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 3005 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i) { 3006 isIdentity = false; 3007 break; 3008 } 3009 } 3010 if (isIdentity) return N->getOperand(0); 3011 3012 // If the shuffle mask is an identity operation on the RHS, return the RHS. 3013 isIdentity = true; 3014 for (unsigned i = 0; i != NumElts; ++i) { 3015 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF && 3016 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() != i+NumElts) { 3017 isIdentity = false; 3018 break; 3019 } 3020 } 3021 if (isIdentity) return N->getOperand(1); 3022 3023 // Check if the shuffle is a unary shuffle, i.e. one of the vectors is not 3024 // needed at all. 3025 bool isUnary = true; 3026 bool isSplat = true; 3027 int VecNum = -1; 3028 unsigned BaseIdx = 0; 3029 for (unsigned i = 0; i != NumElts; ++i) 3030 if (ShufMask.getOperand(i).getOpcode() != ISD::UNDEF) { 3031 unsigned Idx = cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue(); 3032 int V = (Idx < NumElts) ? 0 : 1; 3033 if (VecNum == -1) { 3034 VecNum = V; 3035 BaseIdx = Idx; 3036 } else { 3037 if (BaseIdx != Idx) 3038 isSplat = false; 3039 if (VecNum != V) { 3040 isUnary = false; 3041 break; 3042 } 3043 } 3044 } 3045 3046 SDOperand N0 = N->getOperand(0); 3047 SDOperand N1 = N->getOperand(1); 3048 // Normalize unary shuffle so the RHS is undef. 3049 if (isUnary && VecNum == 1) 3050 std::swap(N0, N1); 3051 3052 // If it is a splat, check if the argument vector is a build_vector with 3053 // all scalar elements the same. 3054 if (isSplat) { 3055 SDNode *V = N0.Val; 3056 if (V->getOpcode() == ISD::VBIT_CONVERT) 3057 V = V->getOperand(0).Val; 3058 if (V->getOpcode() == ISD::VBUILD_VECTOR) { 3059 unsigned NumElems = V->getNumOperands()-2; 3060 if (NumElems > BaseIdx) { 3061 SDOperand Base; 3062 bool AllSame = true; 3063 for (unsigned i = 0; i != NumElems; ++i) { 3064 if (V->getOperand(i).getOpcode() != ISD::UNDEF) { 3065 Base = V->getOperand(i); 3066 break; 3067 } 3068 } 3069 // Splat of <u, u, u, u>, return <u, u, u, u> 3070 if (!Base.Val) 3071 return N0; 3072 for (unsigned i = 0; i != NumElems; ++i) { 3073 if (V->getOperand(i).getOpcode() != ISD::UNDEF && 3074 V->getOperand(i) != Base) { 3075 AllSame = false; 3076 break; 3077 } 3078 } 3079 // Splat of <x, x, x, x>, return <x, x, x, x> 3080 if (AllSame) 3081 return N0; 3082 } 3083 } 3084 } 3085 3086 // If it is a unary or the LHS and the RHS are the same node, turn the RHS 3087 // into an undef. 3088 if (isUnary || N0 == N1) { 3089 // Check the SHUFFLE mask, mapping any inputs from the 2nd operand into the 3090 // first operand. 3091 SmallVector<SDOperand, 8> MappedOps; 3092 for (unsigned i = 0; i != NumElts; ++i) { 3093 if (ShufMask.getOperand(i).getOpcode() == ISD::UNDEF || 3094 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() < NumElts) { 3095 MappedOps.push_back(ShufMask.getOperand(i)); 3096 } else { 3097 unsigned NewIdx = 3098 cast<ConstantSDNode>(ShufMask.getOperand(i))->getValue() - NumElts; 3099 MappedOps.push_back(DAG.getConstant(NewIdx, MVT::i32)); 3100 } 3101 } 3102 // Add the type/#elts values. 3103 MappedOps.push_back(ShufMask.getOperand(NumElts)); 3104 MappedOps.push_back(ShufMask.getOperand(NumElts+1)); 3105 3106 ShufMask = DAG.getNode(ISD::VBUILD_VECTOR, ShufMask.getValueType(), 3107 &MappedOps[0], MappedOps.size()); 3108 AddToWorkList(ShufMask.Val); 3109 3110 // Build the undef vector. 3111 SDOperand UDVal = DAG.getNode(ISD::UNDEF, MappedOps[0].getValueType()); 3112 for (unsigned i = 0; i != NumElts; ++i) 3113 MappedOps[i] = UDVal; 3114 MappedOps[NumElts ] = *(N0.Val->op_end()-2); 3115 MappedOps[NumElts+1] = *(N0.Val->op_end()-1); 3116 UDVal = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 3117 &MappedOps[0], MappedOps.size()); 3118 3119 return DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, 3120 N0, UDVal, ShufMask, 3121 MappedOps[NumElts], MappedOps[NumElts+1]); 3122 } 3123 3124 return SDOperand(); 3125} 3126 3127/// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform 3128/// a VAND to a vector_shuffle with the destination vector and a zero vector. 3129/// e.g. VAND V, <0xffffffff, 0, 0xffffffff, 0>. ==> 3130/// vector_shuffle V, Zero, <0, 4, 2, 4> 3131SDOperand DAGCombiner::XformToShuffleWithZero(SDNode *N) { 3132 SDOperand LHS = N->getOperand(0); 3133 SDOperand RHS = N->getOperand(1); 3134 if (N->getOpcode() == ISD::VAND) { 3135 SDOperand DstVecSize = *(LHS.Val->op_end()-2); 3136 SDOperand DstVecEVT = *(LHS.Val->op_end()-1); 3137 if (RHS.getOpcode() == ISD::VBIT_CONVERT) 3138 RHS = RHS.getOperand(0); 3139 if (RHS.getOpcode() == ISD::VBUILD_VECTOR) { 3140 std::vector<SDOperand> IdxOps; 3141 unsigned NumOps = RHS.getNumOperands(); 3142 unsigned NumElts = NumOps-2; 3143 MVT::ValueType EVT = cast<VTSDNode>(RHS.getOperand(NumOps-1))->getVT(); 3144 for (unsigned i = 0; i != NumElts; ++i) { 3145 SDOperand Elt = RHS.getOperand(i); 3146 if (!isa<ConstantSDNode>(Elt)) 3147 return SDOperand(); 3148 else if (cast<ConstantSDNode>(Elt)->isAllOnesValue()) 3149 IdxOps.push_back(DAG.getConstant(i, EVT)); 3150 else if (cast<ConstantSDNode>(Elt)->isNullValue()) 3151 IdxOps.push_back(DAG.getConstant(NumElts, EVT)); 3152 else 3153 return SDOperand(); 3154 } 3155 3156 // Let's see if the target supports this vector_shuffle. 3157 if (!TLI.isVectorClearMaskLegal(IdxOps, EVT, DAG)) 3158 return SDOperand(); 3159 3160 // Return the new VVECTOR_SHUFFLE node. 3161 SDOperand NumEltsNode = DAG.getConstant(NumElts, MVT::i32); 3162 SDOperand EVTNode = DAG.getValueType(EVT); 3163 std::vector<SDOperand> Ops; 3164 LHS = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, LHS, NumEltsNode, 3165 EVTNode); 3166 Ops.push_back(LHS); 3167 AddToWorkList(LHS.Val); 3168 std::vector<SDOperand> ZeroOps(NumElts, DAG.getConstant(0, EVT)); 3169 ZeroOps.push_back(NumEltsNode); 3170 ZeroOps.push_back(EVTNode); 3171 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 3172 &ZeroOps[0], ZeroOps.size())); 3173 IdxOps.push_back(NumEltsNode); 3174 IdxOps.push_back(EVTNode); 3175 Ops.push_back(DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, 3176 &IdxOps[0], IdxOps.size())); 3177 Ops.push_back(NumEltsNode); 3178 Ops.push_back(EVTNode); 3179 SDOperand Result = DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector, 3180 &Ops[0], Ops.size()); 3181 if (NumEltsNode != DstVecSize || EVTNode != DstVecEVT) { 3182 Result = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, Result, 3183 DstVecSize, DstVecEVT); 3184 } 3185 return Result; 3186 } 3187 } 3188 return SDOperand(); 3189} 3190 3191/// visitVBinOp - Visit a binary vector operation, like VADD. IntOp indicates 3192/// the scalar operation of the vop if it is operating on an integer vector 3193/// (e.g. ADD) and FPOp indicates the FP version (e.g. FADD). 3194SDOperand DAGCombiner::visitVBinOp(SDNode *N, ISD::NodeType IntOp, 3195 ISD::NodeType FPOp) { 3196 MVT::ValueType EltType = cast<VTSDNode>(*(N->op_end()-1))->getVT(); 3197 ISD::NodeType ScalarOp = MVT::isInteger(EltType) ? IntOp : FPOp; 3198 SDOperand LHS = N->getOperand(0); 3199 SDOperand RHS = N->getOperand(1); 3200 SDOperand Shuffle = XformToShuffleWithZero(N); 3201 if (Shuffle.Val) return Shuffle; 3202 3203 // If the LHS and RHS are VBUILD_VECTOR nodes, see if we can constant fold 3204 // this operation. 3205 if (LHS.getOpcode() == ISD::VBUILD_VECTOR && 3206 RHS.getOpcode() == ISD::VBUILD_VECTOR) { 3207 SmallVector<SDOperand, 8> Ops; 3208 for (unsigned i = 0, e = LHS.getNumOperands()-2; i != e; ++i) { 3209 SDOperand LHSOp = LHS.getOperand(i); 3210 SDOperand RHSOp = RHS.getOperand(i); 3211 // If these two elements can't be folded, bail out. 3212 if ((LHSOp.getOpcode() != ISD::UNDEF && 3213 LHSOp.getOpcode() != ISD::Constant && 3214 LHSOp.getOpcode() != ISD::ConstantFP) || 3215 (RHSOp.getOpcode() != ISD::UNDEF && 3216 RHSOp.getOpcode() != ISD::Constant && 3217 RHSOp.getOpcode() != ISD::ConstantFP)) 3218 break; 3219 // Can't fold divide by zero. 3220 if (N->getOpcode() == ISD::VSDIV || N->getOpcode() == ISD::VUDIV) { 3221 if ((RHSOp.getOpcode() == ISD::Constant && 3222 cast<ConstantSDNode>(RHSOp.Val)->isNullValue()) || 3223 (RHSOp.getOpcode() == ISD::ConstantFP && 3224 !cast<ConstantFPSDNode>(RHSOp.Val)->getValue())) 3225 break; 3226 } 3227 Ops.push_back(DAG.getNode(ScalarOp, EltType, LHSOp, RHSOp)); 3228 AddToWorkList(Ops.back().Val); 3229 assert((Ops.back().getOpcode() == ISD::UNDEF || 3230 Ops.back().getOpcode() == ISD::Constant || 3231 Ops.back().getOpcode() == ISD::ConstantFP) && 3232 "Scalar binop didn't fold!"); 3233 } 3234 3235 if (Ops.size() == LHS.getNumOperands()-2) { 3236 Ops.push_back(*(LHS.Val->op_end()-2)); 3237 Ops.push_back(*(LHS.Val->op_end()-1)); 3238 return DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size()); 3239 } 3240 } 3241 3242 return SDOperand(); 3243} 3244 3245SDOperand DAGCombiner::SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2){ 3246 assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!"); 3247 3248 SDOperand SCC = SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), N1, N2, 3249 cast<CondCodeSDNode>(N0.getOperand(2))->get()); 3250 // If we got a simplified select_cc node back from SimplifySelectCC, then 3251 // break it down into a new SETCC node, and a new SELECT node, and then return 3252 // the SELECT node, since we were called with a SELECT node. 3253 if (SCC.Val) { 3254 // Check to see if we got a select_cc back (to turn into setcc/select). 3255 // Otherwise, just return whatever node we got back, like fabs. 3256 if (SCC.getOpcode() == ISD::SELECT_CC) { 3257 SDOperand SETCC = DAG.getNode(ISD::SETCC, N0.getValueType(), 3258 SCC.getOperand(0), SCC.getOperand(1), 3259 SCC.getOperand(4)); 3260 AddToWorkList(SETCC.Val); 3261 return DAG.getNode(ISD::SELECT, SCC.getValueType(), SCC.getOperand(2), 3262 SCC.getOperand(3), SETCC); 3263 } 3264 return SCC; 3265 } 3266 return SDOperand(); 3267} 3268 3269/// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS 3270/// are the two values being selected between, see if we can simplify the 3271/// select. Callers of this should assume that TheSelect is deleted if this 3272/// returns true. As such, they should return the appropriate thing (e.g. the 3273/// node) back to the top-level of the DAG combiner loop to avoid it being 3274/// looked at. 3275/// 3276bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDOperand LHS, 3277 SDOperand RHS) { 3278 3279 // If this is a select from two identical things, try to pull the operation 3280 // through the select. 3281 if (LHS.getOpcode() == RHS.getOpcode() && LHS.hasOneUse() && RHS.hasOneUse()){ 3282#if 0 3283 std::cerr << "SELECT: ["; LHS.Val->dump(); 3284 std::cerr << "] ["; RHS.Val->dump(); 3285 std::cerr << "]\n"; 3286#endif 3287 3288 // If this is a load and the token chain is identical, replace the select 3289 // of two loads with a load through a select of the address to load from. 3290 // This triggers in things like "select bool X, 10.0, 123.0" after the FP 3291 // constants have been dropped into the constant pool. 3292 if ((LHS.getOpcode() == ISD::LOAD || 3293 LHS.getOpcode() == ISD::EXTLOAD || 3294 LHS.getOpcode() == ISD::ZEXTLOAD || 3295 LHS.getOpcode() == ISD::SEXTLOAD) && 3296 // Token chains must be identical. 3297 LHS.getOperand(0) == RHS.getOperand(0) && 3298 // If this is an EXTLOAD, the VT's must match. 3299 (LHS.getOpcode() == ISD::LOAD || 3300 LHS.getOperand(3) == RHS.getOperand(3))) { 3301 // FIXME: this conflates two src values, discarding one. This is not 3302 // the right thing to do, but nothing uses srcvalues now. When they do, 3303 // turn SrcValue into a list of locations. 3304 SDOperand Addr; 3305 if (TheSelect->getOpcode() == ISD::SELECT) 3306 Addr = DAG.getNode(ISD::SELECT, LHS.getOperand(1).getValueType(), 3307 TheSelect->getOperand(0), LHS.getOperand(1), 3308 RHS.getOperand(1)); 3309 else 3310 Addr = DAG.getNode(ISD::SELECT_CC, LHS.getOperand(1).getValueType(), 3311 TheSelect->getOperand(0), 3312 TheSelect->getOperand(1), 3313 LHS.getOperand(1), RHS.getOperand(1), 3314 TheSelect->getOperand(4)); 3315 3316 SDOperand Load; 3317 if (LHS.getOpcode() == ISD::LOAD) 3318 Load = DAG.getLoad(TheSelect->getValueType(0), LHS.getOperand(0), 3319 Addr, LHS.getOperand(2)); 3320 else 3321 Load = DAG.getExtLoad(LHS.getOpcode(), TheSelect->getValueType(0), 3322 LHS.getOperand(0), Addr, LHS.getOperand(2), 3323 cast<VTSDNode>(LHS.getOperand(3))->getVT()); 3324 // Users of the select now use the result of the load. 3325 CombineTo(TheSelect, Load); 3326 3327 // Users of the old loads now use the new load's chain. We know the 3328 // old-load value is dead now. 3329 CombineTo(LHS.Val, Load.getValue(0), Load.getValue(1)); 3330 CombineTo(RHS.Val, Load.getValue(0), Load.getValue(1)); 3331 return true; 3332 } 3333 } 3334 3335 return false; 3336} 3337 3338SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1, 3339 SDOperand N2, SDOperand N3, 3340 ISD::CondCode CC) { 3341 3342 MVT::ValueType VT = N2.getValueType(); 3343 ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val); 3344 ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.Val); 3345 ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.Val); 3346 3347 // Determine if the condition we're dealing with is constant 3348 SDOperand SCC = SimplifySetCC(TLI.getSetCCResultTy(), N0, N1, CC, false); 3349 ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.Val); 3350 3351 // fold select_cc true, x, y -> x 3352 if (SCCC && SCCC->getValue()) 3353 return N2; 3354 // fold select_cc false, x, y -> y 3355 if (SCCC && SCCC->getValue() == 0) 3356 return N3; 3357 3358 // Check to see if we can simplify the select into an fabs node 3359 if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) { 3360 // Allow either -0.0 or 0.0 3361 if (CFP->getValue() == 0.0) { 3362 // select (setg[te] X, +/-0.0), X, fneg(X) -> fabs 3363 if ((CC == ISD::SETGE || CC == ISD::SETGT) && 3364 N0 == N2 && N3.getOpcode() == ISD::FNEG && 3365 N2 == N3.getOperand(0)) 3366 return DAG.getNode(ISD::FABS, VT, N0); 3367 3368 // select (setl[te] X, +/-0.0), fneg(X), X -> fabs 3369 if ((CC == ISD::SETLT || CC == ISD::SETLE) && 3370 N0 == N3 && N2.getOpcode() == ISD::FNEG && 3371 N2.getOperand(0) == N3) 3372 return DAG.getNode(ISD::FABS, VT, N3); 3373 } 3374 } 3375 3376 // Check to see if we can perform the "gzip trick", transforming 3377 // select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A 3378 if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT && 3379 MVT::isInteger(N0.getValueType()) && 3380 MVT::isInteger(N2.getValueType()) && 3381 (N1C->isNullValue() || // (a < 0) ? b : 0 3382 (N1C->getValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0 3383 MVT::ValueType XType = N0.getValueType(); 3384 MVT::ValueType AType = N2.getValueType(); 3385 if (XType >= AType) { 3386 // and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a 3387 // single-bit constant. 3388 if (N2C && ((N2C->getValue() & (N2C->getValue()-1)) == 0)) { 3389 unsigned ShCtV = Log2_64(N2C->getValue()); 3390 ShCtV = MVT::getSizeInBits(XType)-ShCtV-1; 3391 SDOperand ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy()); 3392 SDOperand Shift = DAG.getNode(ISD::SRL, XType, N0, ShCt); 3393 AddToWorkList(Shift.Val); 3394 if (XType > AType) { 3395 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift); 3396 AddToWorkList(Shift.Val); 3397 } 3398 return DAG.getNode(ISD::AND, AType, Shift, N2); 3399 } 3400 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0, 3401 DAG.getConstant(MVT::getSizeInBits(XType)-1, 3402 TLI.getShiftAmountTy())); 3403 AddToWorkList(Shift.Val); 3404 if (XType > AType) { 3405 Shift = DAG.getNode(ISD::TRUNCATE, AType, Shift); 3406 AddToWorkList(Shift.Val); 3407 } 3408 return DAG.getNode(ISD::AND, AType, Shift, N2); 3409 } 3410 } 3411 3412 // fold select C, 16, 0 -> shl C, 4 3413 if (N2C && N3C && N3C->isNullValue() && isPowerOf2_64(N2C->getValue()) && 3414 TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult) { 3415 // Get a SetCC of the condition 3416 // FIXME: Should probably make sure that setcc is legal if we ever have a 3417 // target where it isn't. 3418 SDOperand Temp, SCC; 3419 // cast from setcc result type to select result type 3420 if (AfterLegalize) { 3421 SCC = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC); 3422 Temp = DAG.getZeroExtendInReg(SCC, N2.getValueType()); 3423 } else { 3424 SCC = DAG.getSetCC(MVT::i1, N0, N1, CC); 3425 Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getValueType(), SCC); 3426 } 3427 AddToWorkList(SCC.Val); 3428 AddToWorkList(Temp.Val); 3429 // shl setcc result by log2 n2c 3430 return DAG.getNode(ISD::SHL, N2.getValueType(), Temp, 3431 DAG.getConstant(Log2_64(N2C->getValue()), 3432 TLI.getShiftAmountTy())); 3433 } 3434 3435 // Check to see if this is the equivalent of setcc 3436 // FIXME: Turn all of these into setcc if setcc if setcc is legal 3437 // otherwise, go ahead with the folds. 3438 if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getValue() == 1ULL)) { 3439 MVT::ValueType XType = N0.getValueType(); 3440 if (TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultTy())) { 3441 SDOperand Res = DAG.getSetCC(TLI.getSetCCResultTy(), N0, N1, CC); 3442 if (Res.getValueType() != VT) 3443 Res = DAG.getNode(ISD::ZERO_EXTEND, VT, Res); 3444 return Res; 3445 } 3446 3447 // seteq X, 0 -> srl (ctlz X, log2(size(X))) 3448 if (N1C && N1C->isNullValue() && CC == ISD::SETEQ && 3449 TLI.isOperationLegal(ISD::CTLZ, XType)) { 3450 SDOperand Ctlz = DAG.getNode(ISD::CTLZ, XType, N0); 3451 return DAG.getNode(ISD::SRL, XType, Ctlz, 3452 DAG.getConstant(Log2_32(MVT::getSizeInBits(XType)), 3453 TLI.getShiftAmountTy())); 3454 } 3455 // setgt X, 0 -> srl (and (-X, ~X), size(X)-1) 3456 if (N1C && N1C->isNullValue() && CC == ISD::SETGT) { 3457 SDOperand NegN0 = DAG.getNode(ISD::SUB, XType, DAG.getConstant(0, XType), 3458 N0); 3459 SDOperand NotN0 = DAG.getNode(ISD::XOR, XType, N0, 3460 DAG.getConstant(~0ULL, XType)); 3461 return DAG.getNode(ISD::SRL, XType, 3462 DAG.getNode(ISD::AND, XType, NegN0, NotN0), 3463 DAG.getConstant(MVT::getSizeInBits(XType)-1, 3464 TLI.getShiftAmountTy())); 3465 } 3466 // setgt X, -1 -> xor (srl (X, size(X)-1), 1) 3467 if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) { 3468 SDOperand Sign = DAG.getNode(ISD::SRL, XType, N0, 3469 DAG.getConstant(MVT::getSizeInBits(XType)-1, 3470 TLI.getShiftAmountTy())); 3471 return DAG.getNode(ISD::XOR, XType, Sign, DAG.getConstant(1, XType)); 3472 } 3473 } 3474 3475 // Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X -> 3476 // Y = sra (X, size(X)-1); xor (add (X, Y), Y) 3477 if (N1C && N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE) && 3478 N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1)) { 3479 if (ConstantSDNode *SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0))) { 3480 MVT::ValueType XType = N0.getValueType(); 3481 if (SubC->isNullValue() && MVT::isInteger(XType)) { 3482 SDOperand Shift = DAG.getNode(ISD::SRA, XType, N0, 3483 DAG.getConstant(MVT::getSizeInBits(XType)-1, 3484 TLI.getShiftAmountTy())); 3485 SDOperand Add = DAG.getNode(ISD::ADD, XType, N0, Shift); 3486 AddToWorkList(Shift.Val); 3487 AddToWorkList(Add.Val); 3488 return DAG.getNode(ISD::XOR, XType, Add, Shift); 3489 } 3490 } 3491 } 3492 3493 return SDOperand(); 3494} 3495 3496SDOperand DAGCombiner::SimplifySetCC(MVT::ValueType VT, SDOperand N0, 3497 SDOperand N1, ISD::CondCode Cond, 3498 bool foldBooleans) { 3499 // These setcc operations always fold. 3500 switch (Cond) { 3501 default: break; 3502 case ISD::SETFALSE: 3503 case ISD::SETFALSE2: return DAG.getConstant(0, VT); 3504 case ISD::SETTRUE: 3505 case ISD::SETTRUE2: return DAG.getConstant(1, VT); 3506 } 3507 3508 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) { 3509 uint64_t C1 = N1C->getValue(); 3510 if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.Val)) { 3511 uint64_t C0 = N0C->getValue(); 3512 3513 // Sign extend the operands if required 3514 if (ISD::isSignedIntSetCC(Cond)) { 3515 C0 = N0C->getSignExtended(); 3516 C1 = N1C->getSignExtended(); 3517 } 3518 3519 switch (Cond) { 3520 default: assert(0 && "Unknown integer setcc!"); 3521 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT); 3522 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT); 3523 case ISD::SETULT: return DAG.getConstant(C0 < C1, VT); 3524 case ISD::SETUGT: return DAG.getConstant(C0 > C1, VT); 3525 case ISD::SETULE: return DAG.getConstant(C0 <= C1, VT); 3526 case ISD::SETUGE: return DAG.getConstant(C0 >= C1, VT); 3527 case ISD::SETLT: return DAG.getConstant((int64_t)C0 < (int64_t)C1, VT); 3528 case ISD::SETGT: return DAG.getConstant((int64_t)C0 > (int64_t)C1, VT); 3529 case ISD::SETLE: return DAG.getConstant((int64_t)C0 <= (int64_t)C1, VT); 3530 case ISD::SETGE: return DAG.getConstant((int64_t)C0 >= (int64_t)C1, VT); 3531 } 3532 } else { 3533 // If the LHS is '(srl (ctlz x), 5)', the RHS is 0/1, and this is an 3534 // equality comparison, then we're just comparing whether X itself is 3535 // zero. 3536 if (N0.getOpcode() == ISD::SRL && (C1 == 0 || C1 == 1) && 3537 N0.getOperand(0).getOpcode() == ISD::CTLZ && 3538 N0.getOperand(1).getOpcode() == ISD::Constant) { 3539 unsigned ShAmt = cast<ConstantSDNode>(N0.getOperand(1))->getValue(); 3540 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) && 3541 ShAmt == Log2_32(MVT::getSizeInBits(N0.getValueType()))) { 3542 if ((C1 == 0) == (Cond == ISD::SETEQ)) { 3543 // (srl (ctlz x), 5) == 0 -> X != 0 3544 // (srl (ctlz x), 5) != 1 -> X != 0 3545 Cond = ISD::SETNE; 3546 } else { 3547 // (srl (ctlz x), 5) != 0 -> X == 0 3548 // (srl (ctlz x), 5) == 1 -> X == 0 3549 Cond = ISD::SETEQ; 3550 } 3551 SDOperand Zero = DAG.getConstant(0, N0.getValueType()); 3552 return DAG.getSetCC(VT, N0.getOperand(0).getOperand(0), 3553 Zero, Cond); 3554 } 3555 } 3556 3557 // If the LHS is a ZERO_EXTEND, perform the comparison on the input. 3558 if (N0.getOpcode() == ISD::ZERO_EXTEND) { 3559 unsigned InSize = MVT::getSizeInBits(N0.getOperand(0).getValueType()); 3560 3561 // If the comparison constant has bits in the upper part, the 3562 // zero-extended value could never match. 3563 if (C1 & (~0ULL << InSize)) { 3564 unsigned VSize = MVT::getSizeInBits(N0.getValueType()); 3565 switch (Cond) { 3566 case ISD::SETUGT: 3567 case ISD::SETUGE: 3568 case ISD::SETEQ: return DAG.getConstant(0, VT); 3569 case ISD::SETULT: 3570 case ISD::SETULE: 3571 case ISD::SETNE: return DAG.getConstant(1, VT); 3572 case ISD::SETGT: 3573 case ISD::SETGE: 3574 // True if the sign bit of C1 is set. 3575 return DAG.getConstant((C1 & (1ULL << VSize)) != 0, VT); 3576 case ISD::SETLT: 3577 case ISD::SETLE: 3578 // True if the sign bit of C1 isn't set. 3579 return DAG.getConstant((C1 & (1ULL << VSize)) == 0, VT); 3580 default: 3581 break; 3582 } 3583 } 3584 3585 // Otherwise, we can perform the comparison with the low bits. 3586 switch (Cond) { 3587 case ISD::SETEQ: 3588 case ISD::SETNE: 3589 case ISD::SETUGT: 3590 case ISD::SETUGE: 3591 case ISD::SETULT: 3592 case ISD::SETULE: 3593 return DAG.getSetCC(VT, N0.getOperand(0), 3594 DAG.getConstant(C1, N0.getOperand(0).getValueType()), 3595 Cond); 3596 default: 3597 break; // todo, be more careful with signed comparisons 3598 } 3599 } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG && 3600 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) { 3601 MVT::ValueType ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT(); 3602 unsigned ExtSrcTyBits = MVT::getSizeInBits(ExtSrcTy); 3603 MVT::ValueType ExtDstTy = N0.getValueType(); 3604 unsigned ExtDstTyBits = MVT::getSizeInBits(ExtDstTy); 3605 3606 // If the extended part has any inconsistent bits, it cannot ever 3607 // compare equal. In other words, they have to be all ones or all 3608 // zeros. 3609 uint64_t ExtBits = 3610 (~0ULL >> (64-ExtSrcTyBits)) & (~0ULL << (ExtDstTyBits-1)); 3611 if ((C1 & ExtBits) != 0 && (C1 & ExtBits) != ExtBits) 3612 return DAG.getConstant(Cond == ISD::SETNE, VT); 3613 3614 SDOperand ZextOp; 3615 MVT::ValueType Op0Ty = N0.getOperand(0).getValueType(); 3616 if (Op0Ty == ExtSrcTy) { 3617 ZextOp = N0.getOperand(0); 3618 } else { 3619 int64_t Imm = ~0ULL >> (64-ExtSrcTyBits); 3620 ZextOp = DAG.getNode(ISD::AND, Op0Ty, N0.getOperand(0), 3621 DAG.getConstant(Imm, Op0Ty)); 3622 } 3623 AddToWorkList(ZextOp.Val); 3624 // Otherwise, make this a use of a zext. 3625 return DAG.getSetCC(VT, ZextOp, 3626 DAG.getConstant(C1 & (~0ULL>>(64-ExtSrcTyBits)), 3627 ExtDstTy), 3628 Cond); 3629 } else if ((N1C->getValue() == 0 || N1C->getValue() == 1) && 3630 (Cond == ISD::SETEQ || Cond == ISD::SETNE) && 3631 (N0.getOpcode() == ISD::XOR || 3632 (N0.getOpcode() == ISD::AND && 3633 N0.getOperand(0).getOpcode() == ISD::XOR && 3634 N0.getOperand(1) == N0.getOperand(0).getOperand(1))) && 3635 isa<ConstantSDNode>(N0.getOperand(1)) && 3636 cast<ConstantSDNode>(N0.getOperand(1))->getValue() == 1) { 3637 // If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We can 3638 // only do this if the top bits are known zero. 3639 if (TLI.MaskedValueIsZero(N1, 3640 MVT::getIntVTBitMask(N0.getValueType())-1)) { 3641 // Okay, get the un-inverted input value. 3642 SDOperand Val; 3643 if (N0.getOpcode() == ISD::XOR) 3644 Val = N0.getOperand(0); 3645 else { 3646 assert(N0.getOpcode() == ISD::AND && 3647 N0.getOperand(0).getOpcode() == ISD::XOR); 3648 // ((X^1)&1)^1 -> X & 1 3649 Val = DAG.getNode(ISD::AND, N0.getValueType(), 3650 N0.getOperand(0).getOperand(0), N0.getOperand(1)); 3651 } 3652 return DAG.getSetCC(VT, Val, N1, 3653 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ); 3654 } 3655 } 3656 3657 uint64_t MinVal, MaxVal; 3658 unsigned OperandBitSize = MVT::getSizeInBits(N1C->getValueType(0)); 3659 if (ISD::isSignedIntSetCC(Cond)) { 3660 MinVal = 1ULL << (OperandBitSize-1); 3661 if (OperandBitSize != 1) // Avoid X >> 64, which is undefined. 3662 MaxVal = ~0ULL >> (65-OperandBitSize); 3663 else 3664 MaxVal = 0; 3665 } else { 3666 MinVal = 0; 3667 MaxVal = ~0ULL >> (64-OperandBitSize); 3668 } 3669 3670 // Canonicalize GE/LE comparisons to use GT/LT comparisons. 3671 if (Cond == ISD::SETGE || Cond == ISD::SETUGE) { 3672 if (C1 == MinVal) return DAG.getConstant(1, VT); // X >= MIN --> true 3673 --C1; // X >= C0 --> X > (C0-1) 3674 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()), 3675 (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT); 3676 } 3677 3678 if (Cond == ISD::SETLE || Cond == ISD::SETULE) { 3679 if (C1 == MaxVal) return DAG.getConstant(1, VT); // X <= MAX --> true 3680 ++C1; // X <= C0 --> X < (C0+1) 3681 return DAG.getSetCC(VT, N0, DAG.getConstant(C1, N1.getValueType()), 3682 (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT); 3683 } 3684 3685 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal) 3686 return DAG.getConstant(0, VT); // X < MIN --> false 3687 3688 // Canonicalize setgt X, Min --> setne X, Min 3689 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal) 3690 return DAG.getSetCC(VT, N0, N1, ISD::SETNE); 3691 // Canonicalize setlt X, Max --> setne X, Max 3692 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal) 3693 return DAG.getSetCC(VT, N0, N1, ISD::SETNE); 3694 3695 // If we have setult X, 1, turn it into seteq X, 0 3696 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1) 3697 return DAG.getSetCC(VT, N0, DAG.getConstant(MinVal, N0.getValueType()), 3698 ISD::SETEQ); 3699 // If we have setugt X, Max-1, turn it into seteq X, Max 3700 else if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1) 3701 return DAG.getSetCC(VT, N0, DAG.getConstant(MaxVal, N0.getValueType()), 3702 ISD::SETEQ); 3703 3704 // If we have "setcc X, C0", check to see if we can shrink the immediate 3705 // by changing cc. 3706 3707 // SETUGT X, SINTMAX -> SETLT X, 0 3708 if (Cond == ISD::SETUGT && OperandBitSize != 1 && 3709 C1 == (~0ULL >> (65-OperandBitSize))) 3710 return DAG.getSetCC(VT, N0, DAG.getConstant(0, N1.getValueType()), 3711 ISD::SETLT); 3712 3713 // FIXME: Implement the rest of these. 3714 3715 // Fold bit comparisons when we can. 3716 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) && 3717 VT == N0.getValueType() && N0.getOpcode() == ISD::AND) 3718 if (ConstantSDNode *AndRHS = 3719 dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 3720 if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3 3721 // Perform the xform if the AND RHS is a single bit. 3722 if ((AndRHS->getValue() & (AndRHS->getValue()-1)) == 0) { 3723 return DAG.getNode(ISD::SRL, VT, N0, 3724 DAG.getConstant(Log2_64(AndRHS->getValue()), 3725 TLI.getShiftAmountTy())); 3726 } 3727 } else if (Cond == ISD::SETEQ && C1 == AndRHS->getValue()) { 3728 // (X & 8) == 8 --> (X & 8) >> 3 3729 // Perform the xform if C1 is a single bit. 3730 if ((C1 & (C1-1)) == 0) { 3731 return DAG.getNode(ISD::SRL, VT, N0, 3732 DAG.getConstant(Log2_64(C1),TLI.getShiftAmountTy())); 3733 } 3734 } 3735 } 3736 } 3737 } else if (isa<ConstantSDNode>(N0.Val)) { 3738 // Ensure that the constant occurs on the RHS. 3739 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond)); 3740 } 3741 3742 if (ConstantFPSDNode *N0C = dyn_cast<ConstantFPSDNode>(N0.Val)) 3743 if (ConstantFPSDNode *N1C = dyn_cast<ConstantFPSDNode>(N1.Val)) { 3744 double C0 = N0C->getValue(), C1 = N1C->getValue(); 3745 3746 switch (Cond) { 3747 default: break; // FIXME: Implement the rest of these! 3748 case ISD::SETEQ: return DAG.getConstant(C0 == C1, VT); 3749 case ISD::SETNE: return DAG.getConstant(C0 != C1, VT); 3750 case ISD::SETLT: return DAG.getConstant(C0 < C1, VT); 3751 case ISD::SETGT: return DAG.getConstant(C0 > C1, VT); 3752 case ISD::SETLE: return DAG.getConstant(C0 <= C1, VT); 3753 case ISD::SETGE: return DAG.getConstant(C0 >= C1, VT); 3754 } 3755 } else { 3756 // Ensure that the constant occurs on the RHS. 3757 return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond)); 3758 } 3759 3760 if (N0 == N1) { 3761 // We can always fold X == Y for integer setcc's. 3762 if (MVT::isInteger(N0.getValueType())) 3763 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT); 3764 unsigned UOF = ISD::getUnorderedFlavor(Cond); 3765 if (UOF == 2) // FP operators that are undefined on NaNs. 3766 return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT); 3767 if (UOF == unsigned(ISD::isTrueWhenEqual(Cond))) 3768 return DAG.getConstant(UOF, VT); 3769 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO 3770 // if it is not already. 3771 ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO; 3772 if (NewCond != Cond) 3773 return DAG.getSetCC(VT, N0, N1, NewCond); 3774 } 3775 3776 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) && 3777 MVT::isInteger(N0.getValueType())) { 3778 if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB || 3779 N0.getOpcode() == ISD::XOR) { 3780 // Simplify (X+Y) == (X+Z) --> Y == Z 3781 if (N0.getOpcode() == N1.getOpcode()) { 3782 if (N0.getOperand(0) == N1.getOperand(0)) 3783 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond); 3784 if (N0.getOperand(1) == N1.getOperand(1)) 3785 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(0), Cond); 3786 if (DAG.isCommutativeBinOp(N0.getOpcode())) { 3787 // If X op Y == Y op X, try other combinations. 3788 if (N0.getOperand(0) == N1.getOperand(1)) 3789 return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(0), Cond); 3790 if (N0.getOperand(1) == N1.getOperand(0)) 3791 return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(1), Cond); 3792 } 3793 } 3794 3795 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) { 3796 if (ConstantSDNode *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { 3797 // Turn (X+C1) == C2 --> X == C2-C1 3798 if (N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse()) { 3799 return DAG.getSetCC(VT, N0.getOperand(0), 3800 DAG.getConstant(RHSC->getValue()-LHSR->getValue(), 3801 N0.getValueType()), Cond); 3802 } 3803 3804 // Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0. 3805 if (N0.getOpcode() == ISD::XOR) 3806 // If we know that all of the inverted bits are zero, don't bother 3807 // performing the inversion. 3808 if (TLI.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getValue())) 3809 return DAG.getSetCC(VT, N0.getOperand(0), 3810 DAG.getConstant(LHSR->getValue()^RHSC->getValue(), 3811 N0.getValueType()), Cond); 3812 } 3813 3814 // Turn (C1-X) == C2 --> X == C1-C2 3815 if (ConstantSDNode *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) { 3816 if (N0.getOpcode() == ISD::SUB && N0.Val->hasOneUse()) { 3817 return DAG.getSetCC(VT, N0.getOperand(1), 3818 DAG.getConstant(SUBC->getValue()-RHSC->getValue(), 3819 N0.getValueType()), Cond); 3820 } 3821 } 3822 } 3823 3824 // Simplify (X+Z) == X --> Z == 0 3825 if (N0.getOperand(0) == N1) 3826 return DAG.getSetCC(VT, N0.getOperand(1), 3827 DAG.getConstant(0, N0.getValueType()), Cond); 3828 if (N0.getOperand(1) == N1) { 3829 if (DAG.isCommutativeBinOp(N0.getOpcode())) 3830 return DAG.getSetCC(VT, N0.getOperand(0), 3831 DAG.getConstant(0, N0.getValueType()), Cond); 3832 else { 3833 assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!"); 3834 // (Z-X) == X --> Z == X<<1 3835 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(), 3836 N1, 3837 DAG.getConstant(1,TLI.getShiftAmountTy())); 3838 AddToWorkList(SH.Val); 3839 return DAG.getSetCC(VT, N0.getOperand(0), SH, Cond); 3840 } 3841 } 3842 } 3843 3844 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB || 3845 N1.getOpcode() == ISD::XOR) { 3846 // Simplify X == (X+Z) --> Z == 0 3847 if (N1.getOperand(0) == N0) { 3848 return DAG.getSetCC(VT, N1.getOperand(1), 3849 DAG.getConstant(0, N1.getValueType()), Cond); 3850 } else if (N1.getOperand(1) == N0) { 3851 if (DAG.isCommutativeBinOp(N1.getOpcode())) { 3852 return DAG.getSetCC(VT, N1.getOperand(0), 3853 DAG.getConstant(0, N1.getValueType()), Cond); 3854 } else { 3855 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!"); 3856 // X == (Z-X) --> X<<1 == Z 3857 SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(), N0, 3858 DAG.getConstant(1,TLI.getShiftAmountTy())); 3859 AddToWorkList(SH.Val); 3860 return DAG.getSetCC(VT, SH, N1.getOperand(0), Cond); 3861 } 3862 } 3863 } 3864 } 3865 3866 // Fold away ALL boolean setcc's. 3867 SDOperand Temp; 3868 if (N0.getValueType() == MVT::i1 && foldBooleans) { 3869 switch (Cond) { 3870 default: assert(0 && "Unknown integer setcc!"); 3871 case ISD::SETEQ: // X == Y -> (X^Y)^1 3872 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, N1); 3873 N0 = DAG.getNode(ISD::XOR, MVT::i1, Temp, DAG.getConstant(1, MVT::i1)); 3874 AddToWorkList(Temp.Val); 3875 break; 3876 case ISD::SETNE: // X != Y --> (X^Y) 3877 N0 = DAG.getNode(ISD::XOR, MVT::i1, N0, N1); 3878 break; 3879 case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> X^1 & Y 3880 case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> X^1 & Y 3881 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1)); 3882 N0 = DAG.getNode(ISD::AND, MVT::i1, N1, Temp); 3883 AddToWorkList(Temp.Val); 3884 break; 3885 case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> Y^1 & X 3886 case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> Y^1 & X 3887 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1)); 3888 N0 = DAG.getNode(ISD::AND, MVT::i1, N0, Temp); 3889 AddToWorkList(Temp.Val); 3890 break; 3891 case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> X^1 | Y 3892 case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> X^1 | Y 3893 Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1)); 3894 N0 = DAG.getNode(ISD::OR, MVT::i1, N1, Temp); 3895 AddToWorkList(Temp.Val); 3896 break; 3897 case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> Y^1 | X 3898 case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> Y^1 | X 3899 Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1)); 3900 N0 = DAG.getNode(ISD::OR, MVT::i1, N0, Temp); 3901 break; 3902 } 3903 if (VT != MVT::i1) { 3904 AddToWorkList(N0.Val); 3905 // FIXME: If running after legalize, we probably can't do this. 3906 N0 = DAG.getNode(ISD::ZERO_EXTEND, VT, N0); 3907 } 3908 return N0; 3909 } 3910 3911 // Could not fold it. 3912 return SDOperand(); 3913} 3914 3915/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant, 3916/// return a DAG expression to select that will generate the same value by 3917/// multiplying by a magic number. See: 3918/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 3919SDOperand DAGCombiner::BuildSDIV(SDNode *N) { 3920 std::vector<SDNode*> Built; 3921 SDOperand S = TLI.BuildSDIV(N, DAG, &Built); 3922 3923 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 3924 ii != ee; ++ii) 3925 AddToWorkList(*ii); 3926 return S; 3927} 3928 3929/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant, 3930/// return a DAG expression to select that will generate the same value by 3931/// multiplying by a magic number. See: 3932/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html> 3933SDOperand DAGCombiner::BuildUDIV(SDNode *N) { 3934 std::vector<SDNode*> Built; 3935 SDOperand S = TLI.BuildUDIV(N, DAG, &Built); 3936 3937 for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end(); 3938 ii != ee; ++ii) 3939 AddToWorkList(*ii); 3940 return S; 3941} 3942 3943/// FindBaseOffset - Return true if we can determine base and offset information 3944/// from a given pointer operand. Provides base and offset as a result. 3945bool DAGCombiner::FindBaseOffset(SDOperand Ptr, 3946 SDOperand &Object, int64_t &Offset) { 3947 3948 // Is it a frame variable, global or constant. 3949 if (isa<FrameIndexSDNode>(Ptr) || 3950 isa<ConstantPoolSDNode>(Ptr) || 3951 isa<GlobalAddressSDNode>(Ptr)) { 3952 Object = Ptr; Offset = 0; 3953 return true; 3954 } else if (Ptr.getOpcode() == ISD::ADD && 3955 FindBaseOffset(Ptr.getOperand(0), Object, Offset)) { 3956 // If it's an add of an simple constant then include it in the offset. 3957 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Ptr.getOperand(1))) { 3958 Offset += C->getValue(); 3959 return true; 3960 } 3961 } 3962 3963 return false; 3964} 3965 3966/// isAlias - Return true if there is the possibility that the two addresses 3967/// overlap. 3968bool DAGCombiner::isAlias(SDOperand Ptr1, int64_t Size1, 3969 SDOperand SrcValue1, 3970 SDOperand Ptr2, int64_t Size2, 3971 SDOperand SrcValue2) { 3972 // If they are the same then they must be aliases. 3973 if (Ptr1 == Ptr2) return true; 3974 3975 // Gather base offset information. Objects can be frame variables, globals 3976 // or constants. 3977 SDOperand Object1, Object2; 3978 int64_t Offset1, Offset2; 3979 if (FindBaseOffset(Ptr1, Object1, Offset1) && 3980 FindBaseOffset(Ptr2, Object2, Offset2)) { 3981 // If they have a different base address, then they can't alias. 3982 if (Object1 != Object2) return false; 3983 3984 // Check to see if the addresses overlap. 3985 if ((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1) 3986 return false; 3987 } 3988 3989 // Otherwise we don't know and have to play it safe. 3990 return true; 3991} 3992 3993/// FindAliasInfo - Extracts the relevant alias information from the memory 3994/// node. 3995void DAGCombiner::FindAliasInfo(SDNode *N, 3996 SDOperand &Ptr, int64_t &Size, SDOperand &SrcValue) { 3997 switch (N->getOpcode()) { 3998 case ISD::LOAD: 3999 Ptr = N->getOperand(1); 4000 Size = MVT::getSizeInBits(N->getOperand(1).getValueType()) >> 3; 4001 SrcValue = N->getOperand(2); 4002 break; 4003 case ISD::STORE: 4004 Ptr = N->getOperand(2); 4005 Size = MVT::getSizeInBits(N->getOperand(1).getValueType()) >> 3; 4006 SrcValue = N->getOperand(3); 4007 break; 4008 default: 4009 assert(0 && "getAliasInfo expected a memory op"); 4010 } 4011} 4012 4013/// hasChain - Return true if Op has a chain. Provides chain if present. 4014/// 4015bool DAGCombiner::hasChain(SDOperand Op, SDOperand &Chain) { 4016 if (Op.getNumOperands() == 0) return false; 4017 Chain = Op.getOperand(0); 4018 return Chain.getValueType() == MVT::Other; 4019} 4020 4021/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking 4022/// for a better chain. 4023SDOperand DAGCombiner::FindBetterChain(SDNode *N, SDOperand Chain) { 4024 // Get alias information for node. 4025 SDOperand Ptr; 4026 int64_t Size; 4027 SDOperand SrcValue; 4028 FindAliasInfo(N, Ptr, Size, SrcValue); 4029 4030 // While we don't encounter any aliasing memory nodes walk up chain. 4031 while (true) { 4032 switch (Chain.getOpcode()) { 4033 case ISD::EntryToken: 4034 // Entry token is ideal chain operand. 4035 return Chain; 4036 case ISD::LOAD: 4037 case ISD::STORE: { 4038 // Get alias information for chain. 4039 SDOperand ChainPtr; 4040 int64_t ChainSize; 4041 SDOperand ChainSrcValue; 4042 FindAliasInfo(Chain.Val, ChainPtr, ChainSize, ChainSrcValue); 4043 4044 // If chain is alias then stop here, otherwise continue up chain. 4045 if (isAlias(Ptr, Size, SrcValue, ChainPtr, ChainSize, ChainSrcValue)) 4046 return Chain; 4047 else 4048 Chain = Chain.getOperand(0); 4049 4050 break; 4051 } 4052 case ISD::TokenFactor: { 4053 // Continue up each of token factor operand and accumulate results in 4054 // a new token factor. CSE will handle duplicate elimination. 4055 SmallVector<SDOperand, 8> Ops; // Ops for replacing token factor. 4056 bool Change = false; 4057 4058 // For each token factor operand. 4059 for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i) { 4060 SDOperand Op = Chain.getOperand(i); 4061 SDOperand OpChain = FindBetterChain(N, Op); 4062 4063 // Make sure we don't duplicate an operand. 4064 if (OpChain.getOpcode() != ISD::EntryToken && 4065 std::find(Ops.begin(), Ops.end(), OpChain) == Ops.end()) { 4066 Ops.push_back(OpChain); 4067 } 4068 4069 // If we added a new operand. 4070 Change = Change || Op != OpChain; 4071 } 4072 4073 // If we have new operands. 4074 if (Change) { 4075 // Create a specialized token factor for this chain. getNode CSE will 4076 // handle duplicates. If it's a single operand, getNode will just 4077 // return the opernand instead of a new token factor. 4078 return DAG.getNode(ISD::TokenFactor, MVT::Other, &Ops[0], Ops.size()); 4079 } 4080 4081 // Leave things alone. 4082 return Chain; 4083 } 4084 // For all other instructions we will just have to take what we can get. 4085 default: return Chain; 4086 } 4087 } 4088 4089 return Chain; 4090} 4091 4092// SelectionDAG::Combine - This is the entry point for the file. 4093// 4094void SelectionDAG::Combine(bool RunningAfterLegalize) { 4095 /// run - This is the main entry point to this class. 4096 /// 4097 DAGCombiner(*this).Run(RunningAfterLegalize); 4098} 4099