LegalizeDAG.cpp revision 71c42a0190300a8903aaea80467b88f15f327ea9
1//===-- LegalizeDAG.cpp - Implement SelectionDAG::Legalize ----------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file was developed by the LLVM research group and is distributed under 6// the University of Illinois Open Source License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the SelectionDAG::Legalize method. 11// 12//===----------------------------------------------------------------------===// 13 14#include "llvm/CodeGen/SelectionDAG.h" 15#include "llvm/CodeGen/MachineConstantPool.h" 16#include "llvm/CodeGen/MachineFunction.h" 17#include "llvm/CodeGen/MachineFrameInfo.h" 18#include "llvm/Target/TargetLowering.h" 19#include "llvm/Target/TargetData.h" 20#include "llvm/Target/TargetOptions.h" 21#include "llvm/Constants.h" 22#include <iostream> 23using namespace llvm; 24 25//===----------------------------------------------------------------------===// 26/// SelectionDAGLegalize - This takes an arbitrary SelectionDAG as input and 27/// hacks on it until the target machine can handle it. This involves 28/// eliminating value sizes the machine cannot handle (promoting small sizes to 29/// large sizes or splitting up large values into small values) as well as 30/// eliminating operations the machine cannot handle. 31/// 32/// This code also does a small amount of optimization and recognition of idioms 33/// as part of its processing. For example, if a target does not support a 34/// 'setcc' instruction efficiently, but does support 'brcc' instruction, this 35/// will attempt merge setcc and brc instructions into brcc's. 36/// 37namespace { 38class SelectionDAGLegalize { 39 TargetLowering &TLI; 40 SelectionDAG &DAG; 41 42 /// LegalizeAction - This enum indicates what action we should take for each 43 /// value type the can occur in the program. 44 enum LegalizeAction { 45 Legal, // The target natively supports this value type. 46 Promote, // This should be promoted to the next larger type. 47 Expand, // This integer type should be broken into smaller pieces. 48 }; 49 50 /// ValueTypeActions - This is a bitvector that contains two bits for each 51 /// value type, where the two bits correspond to the LegalizeAction enum. 52 /// This can be queried with "getTypeAction(VT)". 53 unsigned ValueTypeActions; 54 55 /// NeedsAnotherIteration - This is set when we expand a large integer 56 /// operation into smaller integer operations, but the smaller operations are 57 /// not set. This occurs only rarely in practice, for targets that don't have 58 /// 32-bit or larger integer registers. 59 bool NeedsAnotherIteration; 60 61 /// LegalizedNodes - For nodes that are of legal width, and that have more 62 /// than one use, this map indicates what regularized operand to use. This 63 /// allows us to avoid legalizing the same thing more than once. 64 std::map<SDOperand, SDOperand> LegalizedNodes; 65 66 /// PromotedNodes - For nodes that are below legal width, and that have more 67 /// than one use, this map indicates what promoted value to use. This allows 68 /// us to avoid promoting the same thing more than once. 69 std::map<SDOperand, SDOperand> PromotedNodes; 70 71 /// ExpandedNodes - For nodes that need to be expanded, and which have more 72 /// than one use, this map indicates which which operands are the expanded 73 /// version of the input. This allows us to avoid expanding the same node 74 /// more than once. 75 std::map<SDOperand, std::pair<SDOperand, SDOperand> > ExpandedNodes; 76 77 void AddLegalizedOperand(SDOperand From, SDOperand To) { 78 bool isNew = LegalizedNodes.insert(std::make_pair(From, To)).second; 79 assert(isNew && "Got into the map somehow?"); 80 } 81 void AddPromotedOperand(SDOperand From, SDOperand To) { 82 bool isNew = PromotedNodes.insert(std::make_pair(From, To)).second; 83 assert(isNew && "Got into the map somehow?"); 84 } 85 86public: 87 88 SelectionDAGLegalize(TargetLowering &TLI, SelectionDAG &DAG); 89 90 /// Run - While there is still lowering to do, perform a pass over the DAG. 91 /// Most regularization can be done in a single pass, but targets that require 92 /// large values to be split into registers multiple times (e.g. i64 -> 4x 93 /// i16) require iteration for these values (the first iteration will demote 94 /// to i32, the second will demote to i16). 95 void Run() { 96 do { 97 NeedsAnotherIteration = false; 98 LegalizeDAG(); 99 } while (NeedsAnotherIteration); 100 } 101 102 /// getTypeAction - Return how we should legalize values of this type, either 103 /// it is already legal or we need to expand it into multiple registers of 104 /// smaller integer type, or we need to promote it to a larger type. 105 LegalizeAction getTypeAction(MVT::ValueType VT) const { 106 return (LegalizeAction)((ValueTypeActions >> (2*VT)) & 3); 107 } 108 109 /// isTypeLegal - Return true if this type is legal on this target. 110 /// 111 bool isTypeLegal(MVT::ValueType VT) const { 112 return getTypeAction(VT) == Legal; 113 } 114 115private: 116 void LegalizeDAG(); 117 118 SDOperand LegalizeOp(SDOperand O); 119 void ExpandOp(SDOperand O, SDOperand &Lo, SDOperand &Hi); 120 SDOperand PromoteOp(SDOperand O); 121 122 SDOperand getIntPtrConstant(uint64_t Val) { 123 return DAG.getConstant(Val, TLI.getPointerTy()); 124 } 125}; 126} 127 128 129SelectionDAGLegalize::SelectionDAGLegalize(TargetLowering &tli, 130 SelectionDAG &dag) 131 : TLI(tli), DAG(dag), ValueTypeActions(TLI.getValueTypeActions()) { 132 assert(MVT::LAST_VALUETYPE <= 16 && 133 "Too many value types for ValueTypeActions to hold!"); 134} 135 136void SelectionDAGLegalize::LegalizeDAG() { 137 SDOperand OldRoot = DAG.getRoot(); 138 SDOperand NewRoot = LegalizeOp(OldRoot); 139 DAG.setRoot(NewRoot); 140 141 ExpandedNodes.clear(); 142 LegalizedNodes.clear(); 143 PromotedNodes.clear(); 144 145 // Remove dead nodes now. 146 DAG.RemoveDeadNodes(OldRoot.Val); 147} 148 149SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) { 150 assert(getTypeAction(Op.getValueType()) == Legal && 151 "Caller should expand or promote operands that are not legal!"); 152 153 // If this operation defines any values that cannot be represented in a 154 // register on this target, make sure to expand or promote them. 155 if (Op.Val->getNumValues() > 1) { 156 for (unsigned i = 0, e = Op.Val->getNumValues(); i != e; ++i) 157 switch (getTypeAction(Op.Val->getValueType(i))) { 158 case Legal: break; // Nothing to do. 159 case Expand: { 160 SDOperand T1, T2; 161 ExpandOp(Op.getValue(i), T1, T2); 162 assert(LegalizedNodes.count(Op) && 163 "Expansion didn't add legal operands!"); 164 return LegalizedNodes[Op]; 165 } 166 case Promote: 167 PromoteOp(Op.getValue(i)); 168 assert(LegalizedNodes.count(Op) && 169 "Expansion didn't add legal operands!"); 170 return LegalizedNodes[Op]; 171 } 172 } 173 174 std::map<SDOperand, SDOperand>::iterator I = LegalizedNodes.find(Op); 175 if (I != LegalizedNodes.end()) return I->second; 176 177 SDOperand Tmp1, Tmp2, Tmp3; 178 179 SDOperand Result = Op; 180 SDNode *Node = Op.Val; 181 182 switch (Node->getOpcode()) { 183 default: 184 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n"; 185 assert(0 && "Do not know how to legalize this operator!"); 186 abort(); 187 case ISD::EntryToken: 188 case ISD::FrameIndex: 189 case ISD::GlobalAddress: 190 case ISD::ExternalSymbol: 191 case ISD::ConstantPool: // Nothing to do. 192 assert(getTypeAction(Node->getValueType(0)) == Legal && 193 "This must be legal!"); 194 break; 195 case ISD::CopyFromReg: 196 Tmp1 = LegalizeOp(Node->getOperand(0)); 197 if (Tmp1 != Node->getOperand(0)) 198 Result = DAG.getCopyFromReg(cast<RegSDNode>(Node)->getReg(), 199 Node->getValueType(0), Tmp1); 200 break; 201 case ISD::ImplicitDef: 202 Tmp1 = LegalizeOp(Node->getOperand(0)); 203 if (Tmp1 != Node->getOperand(0)) 204 Result = DAG.getImplicitDef(Tmp1, cast<RegSDNode>(Node)->getReg()); 205 break; 206 case ISD::Constant: 207 // We know we don't need to expand constants here, constants only have one 208 // value and we check that it is fine above. 209 210 // FIXME: Maybe we should handle things like targets that don't support full 211 // 32-bit immediates? 212 break; 213 case ISD::ConstantFP: { 214 // Spill FP immediates to the constant pool if the target cannot directly 215 // codegen them. Targets often have some immediate values that can be 216 // efficiently generated into an FP register without a load. We explicitly 217 // leave these constants as ConstantFP nodes for the target to deal with. 218 219 ConstantFPSDNode *CFP = cast<ConstantFPSDNode>(Node); 220 221 // Check to see if this FP immediate is already legal. 222 bool isLegal = false; 223 for (TargetLowering::legal_fpimm_iterator I = TLI.legal_fpimm_begin(), 224 E = TLI.legal_fpimm_end(); I != E; ++I) 225 if (CFP->isExactlyValue(*I)) { 226 isLegal = true; 227 break; 228 } 229 230 if (!isLegal) { 231 // Otherwise we need to spill the constant to memory. 232 MachineConstantPool *CP = DAG.getMachineFunction().getConstantPool(); 233 234 bool Extend = false; 235 236 // If a FP immediate is precise when represented as a float, we put it 237 // into the constant pool as a float, even if it's is statically typed 238 // as a double. 239 MVT::ValueType VT = CFP->getValueType(0); 240 bool isDouble = VT == MVT::f64; 241 ConstantFP *LLVMC = ConstantFP::get(isDouble ? Type::DoubleTy : 242 Type::FloatTy, CFP->getValue()); 243 if (isDouble && CFP->isExactlyValue((float)CFP->getValue())) { 244 LLVMC = cast<ConstantFP>(ConstantExpr::getCast(LLVMC, Type::FloatTy)); 245 VT = MVT::f32; 246 Extend = true; 247 } 248 249 SDOperand CPIdx = DAG.getConstantPool(CP->getConstantPoolIndex(LLVMC), 250 TLI.getPointerTy()); 251 Result = DAG.getLoad(VT, DAG.getEntryNode(), CPIdx); 252 253 if (Extend) Result = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Result); 254 } 255 break; 256 } 257 case ISD::TokenFactor: { 258 std::vector<SDOperand> Ops; 259 bool Changed = false; 260 for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) { 261 Ops.push_back(LegalizeOp(Node->getOperand(i))); // Legalize the operands 262 Changed |= Ops[i] != Node->getOperand(i); 263 } 264 if (Changed) 265 Result = DAG.getNode(ISD::TokenFactor, MVT::Other, Ops); 266 break; 267 } 268 269 case ISD::ADJCALLSTACKDOWN: 270 case ISD::ADJCALLSTACKUP: 271 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 272 // There is no need to legalize the size argument (Operand #1) 273 if (Tmp1 != Node->getOperand(0)) 274 Result = DAG.getNode(Node->getOpcode(), MVT::Other, Tmp1, 275 Node->getOperand(1)); 276 break; 277 case ISD::DYNAMIC_STACKALLOC: 278 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 279 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the size. 280 Tmp3 = LegalizeOp(Node->getOperand(2)); // Legalize the alignment. 281 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || 282 Tmp3 != Node->getOperand(2)) 283 Result = DAG.getNode(ISD::DYNAMIC_STACKALLOC, Node->getValueType(0), 284 Tmp1, Tmp2, Tmp3); 285 else 286 Result = Op.getValue(0); 287 288 // Since this op produces two values, make sure to remember that we 289 // legalized both of them. 290 AddLegalizedOperand(SDOperand(Node, 0), Result); 291 AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1)); 292 return Result.getValue(Op.ResNo); 293 294 case ISD::CALL: 295 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 296 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the callee. 297 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) { 298 std::vector<MVT::ValueType> RetTyVTs; 299 RetTyVTs.reserve(Node->getNumValues()); 300 for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i) 301 RetTyVTs.push_back(Node->getValueType(i)); 302 Result = SDOperand(DAG.getCall(RetTyVTs, Tmp1, Tmp2), 0); 303 } else { 304 Result = Result.getValue(0); 305 } 306 // Since calls produce multiple values, make sure to remember that we 307 // legalized all of them. 308 for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i) 309 AddLegalizedOperand(SDOperand(Node, i), Result.getValue(i)); 310 return Result.getValue(Op.ResNo); 311 312 case ISD::BR: 313 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 314 if (Tmp1 != Node->getOperand(0)) 315 Result = DAG.getNode(ISD::BR, MVT::Other, Tmp1, Node->getOperand(1)); 316 break; 317 318 case ISD::BRCOND: 319 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 320 // FIXME: booleans might not be legal! 321 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the condition. 322 // Basic block destination (Op#2) is always legal. 323 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) 324 Result = DAG.getNode(ISD::BRCOND, MVT::Other, Tmp1, Tmp2, 325 Node->getOperand(2)); 326 break; 327 328 case ISD::LOAD: 329 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 330 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer. 331 if (Tmp1 != Node->getOperand(0) || 332 Tmp2 != Node->getOperand(1)) 333 Result = DAG.getLoad(Node->getValueType(0), Tmp1, Tmp2); 334 else 335 Result = SDOperand(Node, 0); 336 337 // Since loads produce two values, make sure to remember that we legalized 338 // both of them. 339 AddLegalizedOperand(SDOperand(Node, 0), Result); 340 AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1)); 341 return Result.getValue(Op.ResNo); 342 343 case ISD::EXTLOAD: 344 case ISD::SEXTLOAD: 345 case ISD::ZEXTLOAD: 346 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 347 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer. 348 if (Tmp1 != Node->getOperand(0) || 349 Tmp2 != Node->getOperand(1)) 350 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1, Tmp2, 351 cast<MVTSDNode>(Node)->getExtraValueType()); 352 else 353 Result = SDOperand(Node, 0); 354 355 // Since loads produce two values, make sure to remember that we legalized 356 // both of them. 357 AddLegalizedOperand(SDOperand(Node, 0), Result); 358 AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1)); 359 return Result.getValue(Op.ResNo); 360 361 case ISD::EXTRACT_ELEMENT: 362 // Get both the low and high parts. 363 ExpandOp(Node->getOperand(0), Tmp1, Tmp2); 364 if (cast<ConstantSDNode>(Node->getOperand(1))->getValue()) 365 Result = Tmp2; // 1 -> Hi 366 else 367 Result = Tmp1; // 0 -> Lo 368 break; 369 370 case ISD::CopyToReg: 371 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 372 373 switch (getTypeAction(Node->getOperand(1).getValueType())) { 374 case Legal: 375 // Legalize the incoming value (must be legal). 376 Tmp2 = LegalizeOp(Node->getOperand(1)); 377 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) 378 Result = DAG.getCopyToReg(Tmp1, Tmp2, cast<RegSDNode>(Node)->getReg()); 379 break; 380 case Expand: { 381 SDOperand Lo, Hi; 382 ExpandOp(Node->getOperand(1), Lo, Hi); 383 unsigned Reg = cast<RegSDNode>(Node)->getReg(); 384 Result = DAG.getCopyToReg(Tmp1, Lo, Reg); 385 Result = DAG.getCopyToReg(Result, Hi, Reg+1); 386 assert(isTypeLegal(Result.getValueType()) && 387 "Cannot expand multiple times yet (i64 -> i16)"); 388 break; 389 } 390 case Promote: 391 assert(0 && "Don't know what it means to promote this!"); 392 abort(); 393 } 394 break; 395 396 case ISD::RET: 397 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 398 switch (Node->getNumOperands()) { 399 case 2: // ret val 400 switch (getTypeAction(Node->getOperand(1).getValueType())) { 401 case Legal: 402 Tmp2 = LegalizeOp(Node->getOperand(1)); 403 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) 404 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Tmp2); 405 break; 406 case Expand: { 407 SDOperand Lo, Hi; 408 ExpandOp(Node->getOperand(1), Lo, Hi); 409 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Lo, Hi); 410 break; 411 } 412 case Promote: 413 Tmp2 = PromoteOp(Node->getOperand(1)); 414 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Tmp2); 415 break; 416 } 417 break; 418 case 1: // ret void 419 if (Tmp1 != Node->getOperand(0)) 420 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1); 421 break; 422 default: { // ret <values> 423 std::vector<SDOperand> NewValues; 424 NewValues.push_back(Tmp1); 425 for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i) 426 switch (getTypeAction(Node->getOperand(i).getValueType())) { 427 case Legal: 428 NewValues.push_back(LegalizeOp(Node->getOperand(i))); 429 break; 430 case Expand: { 431 SDOperand Lo, Hi; 432 ExpandOp(Node->getOperand(i), Lo, Hi); 433 NewValues.push_back(Lo); 434 NewValues.push_back(Hi); 435 break; 436 } 437 case Promote: 438 assert(0 && "Can't promote multiple return value yet!"); 439 } 440 Result = DAG.getNode(ISD::RET, MVT::Other, NewValues); 441 break; 442 } 443 } 444 break; 445 case ISD::STORE: 446 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 447 Tmp2 = LegalizeOp(Node->getOperand(2)); // Legalize the pointer. 448 449 // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr' 450 if (ConstantFPSDNode *CFP =dyn_cast<ConstantFPSDNode>(Node->getOperand(1))){ 451 if (CFP->getValueType(0) == MVT::f32) { 452 union { 453 unsigned I; 454 float F; 455 } V; 456 V.F = CFP->getValue(); 457 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, 458 DAG.getConstant(V.I, MVT::i32), Tmp2); 459 } else { 460 assert(CFP->getValueType(0) == MVT::f64 && "Unknown FP type!"); 461 union { 462 uint64_t I; 463 double F; 464 } V; 465 V.F = CFP->getValue(); 466 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, 467 DAG.getConstant(V.I, MVT::i64), Tmp2); 468 } 469 Op = Result; 470 Node = Op.Val; 471 } 472 473 switch (getTypeAction(Node->getOperand(1).getValueType())) { 474 case Legal: { 475 SDOperand Val = LegalizeOp(Node->getOperand(1)); 476 if (Val != Node->getOperand(1) || Tmp1 != Node->getOperand(0) || 477 Tmp2 != Node->getOperand(2)) 478 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Val, Tmp2); 479 break; 480 } 481 case Promote: 482 // Truncate the value and store the result. 483 Tmp3 = PromoteOp(Node->getOperand(1)); 484 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, Tmp1, Tmp3, Tmp2, 485 Node->getOperand(1).getValueType()); 486 break; 487 488 case Expand: 489 SDOperand Lo, Hi; 490 ExpandOp(Node->getOperand(1), Lo, Hi); 491 492 if (!TLI.isLittleEndian()) 493 std::swap(Lo, Hi); 494 495 // FIXME: These two stores are independent of each other! 496 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Lo, Tmp2); 497 498 unsigned IncrementSize = MVT::getSizeInBits(Lo.getValueType())/8; 499 Tmp2 = DAG.getNode(ISD::ADD, Tmp2.getValueType(), Tmp2, 500 getIntPtrConstant(IncrementSize)); 501 assert(isTypeLegal(Tmp2.getValueType()) && 502 "Pointers must be legal!"); 503 Result = DAG.getNode(ISD::STORE, MVT::Other, Result, Hi, Tmp2); 504 } 505 break; 506 case ISD::TRUNCSTORE: 507 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 508 Tmp3 = LegalizeOp(Node->getOperand(2)); // Legalize the pointer. 509 510 switch (getTypeAction(Node->getOperand(1).getValueType())) { 511 case Legal: 512 Tmp2 = LegalizeOp(Node->getOperand(1)); 513 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || 514 Tmp3 != Node->getOperand(2)) 515 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, Tmp1, Tmp2, Tmp3, 516 cast<MVTSDNode>(Node)->getExtraValueType()); 517 break; 518 case Promote: 519 case Expand: 520 assert(0 && "Cannot handle illegal TRUNCSTORE yet!"); 521 } 522 break; 523 case ISD::SELECT: 524 // FIXME: BOOLS MAY REQUIRE PROMOTION! 525 Tmp1 = LegalizeOp(Node->getOperand(0)); // Cond 526 Tmp2 = LegalizeOp(Node->getOperand(1)); // TrueVal 527 Tmp3 = LegalizeOp(Node->getOperand(2)); // FalseVal 528 529 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || 530 Tmp3 != Node->getOperand(2)) 531 Result = DAG.getNode(ISD::SELECT, Node->getValueType(0), Tmp1, Tmp2,Tmp3); 532 break; 533 case ISD::SETCC: 534 switch (getTypeAction(Node->getOperand(0).getValueType())) { 535 case Legal: 536 Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS 537 Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS 538 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) 539 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(), 540 Tmp1, Tmp2); 541 break; 542 case Promote: 543 Tmp1 = PromoteOp(Node->getOperand(0)); // LHS 544 Tmp2 = PromoteOp(Node->getOperand(1)); // RHS 545 546 // If this is an FP compare, the operands have already been extended. 547 if (MVT::isInteger(Node->getOperand(0).getValueType())) { 548 MVT::ValueType VT = Node->getOperand(0).getValueType(); 549 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT); 550 551 // Otherwise, we have to insert explicit sign or zero extends. Note 552 // that we could insert sign extends for ALL conditions, but zero extend 553 // is cheaper on many machines (an AND instead of two shifts), so prefer 554 // it. 555 switch (cast<SetCCSDNode>(Node)->getCondition()) { 556 default: assert(0 && "Unknown integer comparison!"); 557 case ISD::SETEQ: 558 case ISD::SETNE: 559 case ISD::SETUGE: 560 case ISD::SETUGT: 561 case ISD::SETULE: 562 case ISD::SETULT: 563 // ALL of these operations will work if we either sign or zero extend 564 // the operands (including the unsigned comparisons!). Zero extend is 565 // usually a simpler/cheaper operation, so prefer it. 566 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT); 567 Tmp2 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp2, VT); 568 break; 569 case ISD::SETGE: 570 case ISD::SETGT: 571 case ISD::SETLT: 572 case ISD::SETLE: 573 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT); 574 Tmp2 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp2, VT); 575 break; 576 } 577 578 } 579 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(), 580 Tmp1, Tmp2); 581 break; 582 case Expand: 583 SDOperand LHSLo, LHSHi, RHSLo, RHSHi; 584 ExpandOp(Node->getOperand(0), LHSLo, LHSHi); 585 ExpandOp(Node->getOperand(1), RHSLo, RHSHi); 586 switch (cast<SetCCSDNode>(Node)->getCondition()) { 587 case ISD::SETEQ: 588 case ISD::SETNE: 589 Tmp1 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSLo, RHSLo); 590 Tmp2 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSHi, RHSHi); 591 Tmp1 = DAG.getNode(ISD::OR, Tmp1.getValueType(), Tmp1, Tmp2); 592 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(), Tmp1, 593 DAG.getConstant(0, Tmp1.getValueType())); 594 break; 595 default: 596 // FIXME: This generated code sucks. 597 ISD::CondCode LowCC; 598 switch (cast<SetCCSDNode>(Node)->getCondition()) { 599 default: assert(0 && "Unknown integer setcc!"); 600 case ISD::SETLT: 601 case ISD::SETULT: LowCC = ISD::SETULT; break; 602 case ISD::SETGT: 603 case ISD::SETUGT: LowCC = ISD::SETUGT; break; 604 case ISD::SETLE: 605 case ISD::SETULE: LowCC = ISD::SETULE; break; 606 case ISD::SETGE: 607 case ISD::SETUGE: LowCC = ISD::SETUGE; break; 608 } 609 610 // Tmp1 = lo(op1) < lo(op2) // Always unsigned comparison 611 // Tmp2 = hi(op1) < hi(op2) // Signedness depends on operands 612 // dest = hi(op1) == hi(op2) ? Tmp1 : Tmp2; 613 614 // NOTE: on targets without efficient SELECT of bools, we can always use 615 // this identity: (B1 ? B2 : B3) --> (B1 & B2)|(!B1&B3) 616 Tmp1 = DAG.getSetCC(LowCC, LHSLo, RHSLo); 617 Tmp2 = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(), 618 LHSHi, RHSHi); 619 Result = DAG.getSetCC(ISD::SETEQ, LHSHi, RHSHi); 620 Result = DAG.getNode(ISD::SELECT, MVT::i1, Result, Tmp1, Tmp2); 621 break; 622 } 623 } 624 break; 625 626 case ISD::MEMSET: 627 case ISD::MEMCPY: 628 case ISD::MEMMOVE: { 629 Tmp1 = LegalizeOp(Node->getOperand(0)); 630 Tmp2 = LegalizeOp(Node->getOperand(1)); 631 Tmp3 = LegalizeOp(Node->getOperand(2)); 632 SDOperand Tmp4 = LegalizeOp(Node->getOperand(3)); 633 SDOperand Tmp5 = LegalizeOp(Node->getOperand(4)); 634 if (TLI.isOperationSupported(Node->getOpcode(), MVT::Other)) { 635 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || 636 Tmp3 != Node->getOperand(2) || Tmp4 != Node->getOperand(3) || 637 Tmp5 != Node->getOperand(4)) { 638 std::vector<SDOperand> Ops; 639 Ops.push_back(Tmp1); Ops.push_back(Tmp2); Ops.push_back(Tmp3); 640 Ops.push_back(Tmp4); Ops.push_back(Tmp5); 641 Result = DAG.getNode(Node->getOpcode(), MVT::Other, Ops); 642 } 643 } else { 644 // Otherwise, the target does not support this operation. Lower the 645 // operation to an explicit libcall as appropriate. 646 MVT::ValueType IntPtr = TLI.getPointerTy(); 647 const Type *IntPtrTy = TLI.getTargetData().getIntPtrType(); 648 std::vector<std::pair<SDOperand, const Type*> > Args; 649 650 const char *FnName = 0; 651 if (Node->getOpcode() == ISD::MEMSET) { 652 Args.push_back(std::make_pair(Tmp2, IntPtrTy)); 653 // Extend the ubyte argument to be an int value for the call. 654 Tmp3 = DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Tmp3); 655 Args.push_back(std::make_pair(Tmp3, Type::IntTy)); 656 Args.push_back(std::make_pair(Tmp4, IntPtrTy)); 657 658 FnName = "memset"; 659 } else if (Node->getOpcode() == ISD::MEMCPY || 660 Node->getOpcode() == ISD::MEMMOVE) { 661 Args.push_back(std::make_pair(Tmp2, IntPtrTy)); 662 Args.push_back(std::make_pair(Tmp3, IntPtrTy)); 663 Args.push_back(std::make_pair(Tmp4, IntPtrTy)); 664 FnName = Node->getOpcode() == ISD::MEMMOVE ? "memmove" : "memcpy"; 665 } else { 666 assert(0 && "Unknown op!"); 667 } 668 std::pair<SDOperand,SDOperand> CallResult = 669 TLI.LowerCallTo(Tmp1, Type::VoidTy, 670 DAG.getExternalSymbol(FnName, IntPtr), Args, DAG); 671 Result = LegalizeOp(CallResult.second); 672 } 673 break; 674 } 675 case ISD::ADD: 676 case ISD::SUB: 677 case ISD::MUL: 678 case ISD::UDIV: 679 case ISD::SDIV: 680 case ISD::UREM: 681 case ISD::SREM: 682 case ISD::AND: 683 case ISD::OR: 684 case ISD::XOR: 685 case ISD::SHL: 686 case ISD::SRL: 687 case ISD::SRA: 688 Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS 689 Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS 690 if (Tmp1 != Node->getOperand(0) || 691 Tmp2 != Node->getOperand(1)) 692 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1,Tmp2); 693 break; 694 case ISD::ZERO_EXTEND: 695 case ISD::SIGN_EXTEND: 696 case ISD::TRUNCATE: 697 case ISD::FP_EXTEND: 698 case ISD::FP_ROUND: 699 case ISD::FP_TO_SINT: 700 case ISD::FP_TO_UINT: 701 case ISD::SINT_TO_FP: 702 case ISD::UINT_TO_FP: 703 switch (getTypeAction(Node->getOperand(0).getValueType())) { 704 case Legal: 705 Tmp1 = LegalizeOp(Node->getOperand(0)); 706 if (Tmp1 != Node->getOperand(0)) 707 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1); 708 break; 709 case Expand: 710 assert(Node->getOpcode() != ISD::SINT_TO_FP && 711 Node->getOpcode() != ISD::UINT_TO_FP && 712 "Cannot lower Xint_to_fp to a call yet!"); 713 714 // In the expand case, we must be dealing with a truncate, because 715 // otherwise the result would be larger than the source. 716 assert(Node->getOpcode() == ISD::TRUNCATE && 717 "Shouldn't need to expand other operators here!"); 718 ExpandOp(Node->getOperand(0), Tmp1, Tmp2); 719 720 // Since the result is legal, we should just be able to truncate the low 721 // part of the source. 722 Result = DAG.getNode(ISD::TRUNCATE, Node->getValueType(0), Tmp1); 723 break; 724 725 case Promote: 726 switch (Node->getOpcode()) { 727 case ISD::ZERO_EXTEND: 728 Result = PromoteOp(Node->getOperand(0)); 729 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, Result.getValueType(), 730 Result, Node->getOperand(0).getValueType()); 731 break; 732 case ISD::SIGN_EXTEND: 733 Result = PromoteOp(Node->getOperand(0)); 734 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(), 735 Result, Node->getOperand(0).getValueType()); 736 break; 737 case ISD::TRUNCATE: 738 Result = PromoteOp(Node->getOperand(0)); 739 Result = DAG.getNode(ISD::TRUNCATE, Op.getValueType(), Result); 740 break; 741 case ISD::FP_EXTEND: 742 Result = PromoteOp(Node->getOperand(0)); 743 if (Result.getValueType() != Op.getValueType()) 744 // Dynamically dead while we have only 2 FP types. 745 Result = DAG.getNode(ISD::FP_EXTEND, Op.getValueType(), Result); 746 break; 747 case ISD::FP_ROUND: 748 Result = PromoteOp(Node->getOperand(0)); 749 Result = DAG.getNode(ISD::FP_ROUND, Op.getValueType(), Result); 750 break; 751 case ISD::FP_TO_SINT: 752 case ISD::FP_TO_UINT: 753 case ISD::SINT_TO_FP: 754 case ISD::UINT_TO_FP: 755 Node->dump(); 756 assert(0 && "Do not know how to promote this yet!"); 757 } 758 } 759 break; 760 case ISD::FP_ROUND_INREG: 761 case ISD::SIGN_EXTEND_INREG: 762 case ISD::ZERO_EXTEND_INREG: { 763 Tmp1 = LegalizeOp(Node->getOperand(0)); 764 MVT::ValueType ExtraVT = cast<MVTSDNode>(Node)->getExtraValueType(); 765 766 // If this operation is not supported, convert it to a shl/shr or load/store 767 // pair. 768 if (!TLI.isOperationSupported(Node->getOpcode(), ExtraVT)) { 769 // If this is an integer extend and shifts are supported, do that. 770 if (Node->getOpcode() == ISD::ZERO_EXTEND_INREG) { 771 // NOTE: we could fall back on load/store here too for targets without 772 // AND. However, it is doubtful that any exist. 773 // AND out the appropriate bits. 774 SDOperand Mask = 775 DAG.getConstant((1ULL << MVT::getSizeInBits(ExtraVT))-1, 776 Node->getValueType(0)); 777 Result = DAG.getNode(ISD::AND, Node->getValueType(0), 778 Node->getOperand(0), Mask); 779 } else if (Node->getOpcode() == ISD::SIGN_EXTEND_INREG) { 780 // NOTE: we could fall back on load/store here too for targets without 781 // SAR. However, it is doubtful that any exist. 782 unsigned BitsDiff = MVT::getSizeInBits(Node->getValueType(0)) - 783 MVT::getSizeInBits(ExtraVT); 784 SDOperand ShiftCst = DAG.getConstant(BitsDiff, MVT::i8); 785 Result = DAG.getNode(ISD::SHL, Node->getValueType(0), 786 Node->getOperand(0), ShiftCst); 787 Result = DAG.getNode(ISD::SRA, Node->getValueType(0), 788 Result, ShiftCst); 789 } else if (Node->getOpcode() == ISD::FP_ROUND_INREG) { 790 // The only way we can lower this is to turn it into a STORETRUNC, 791 // EXTLOAD pair, targetting a temporary location (a stack slot). 792 793 // NOTE: there is a choice here between constantly creating new stack 794 // slots and always reusing the same one. We currently always create 795 // new ones, as reuse may inhibit scheduling. 796 const Type *Ty = MVT::getTypeForValueType(ExtraVT); 797 unsigned TySize = (unsigned)TLI.getTargetData().getTypeSize(Ty); 798 unsigned Align = TLI.getTargetData().getTypeAlignment(Ty); 799 MachineFunction &MF = DAG.getMachineFunction(); 800 int SSFI = 801 MF.getFrameInfo()->CreateStackObject((unsigned)TySize, Align); 802 SDOperand StackSlot = DAG.getFrameIndex(SSFI, TLI.getPointerTy()); 803 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, DAG.getEntryNode(), 804 Node->getOperand(0), StackSlot, ExtraVT); 805 Result = DAG.getNode(ISD::EXTLOAD, Node->getValueType(0), 806 Result, StackSlot, ExtraVT); 807 } else { 808 assert(0 && "Unknown op"); 809 } 810 Result = LegalizeOp(Result); 811 } else { 812 if (Tmp1 != Node->getOperand(0)) 813 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1, 814 ExtraVT); 815 } 816 break; 817 } 818 } 819 820 if (!Op.Val->hasOneUse()) 821 AddLegalizedOperand(Op, Result); 822 823 return Result; 824} 825 826/// PromoteOp - Given an operation that produces a value in an invalid type, 827/// promote it to compute the value into a larger type. The produced value will 828/// have the correct bits for the low portion of the register, but no guarantee 829/// is made about the top bits: it may be zero, sign-extended, or garbage. 830SDOperand SelectionDAGLegalize::PromoteOp(SDOperand Op) { 831 MVT::ValueType VT = Op.getValueType(); 832 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT); 833 assert(getTypeAction(VT) == Promote && 834 "Caller should expand or legalize operands that are not promotable!"); 835 assert(NVT > VT && MVT::isInteger(NVT) == MVT::isInteger(VT) && 836 "Cannot promote to smaller type!"); 837 838 std::map<SDOperand, SDOperand>::iterator I = PromotedNodes.find(Op); 839 if (I != PromotedNodes.end()) return I->second; 840 841 SDOperand Tmp1, Tmp2, Tmp3; 842 843 SDOperand Result; 844 SDNode *Node = Op.Val; 845 846 // Promotion needs an optimization step to clean up after it, and is not 847 // careful to avoid operations the target does not support. Make sure that 848 // all generated operations are legalized in the next iteration. 849 NeedsAnotherIteration = true; 850 851 switch (Node->getOpcode()) { 852 default: 853 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n"; 854 assert(0 && "Do not know how to promote this operator!"); 855 abort(); 856 case ISD::CALL: 857 assert(0 && "Target's LowerCallTo implementation is buggy, returning value" 858 " types that are not supported by the target!"); 859 case ISD::Constant: 860 Result = DAG.getNode(ISD::ZERO_EXTEND, NVT, Op); 861 assert(isa<ConstantSDNode>(Result) && "Didn't constant fold zext?"); 862 break; 863 case ISD::ConstantFP: 864 Result = DAG.getNode(ISD::FP_EXTEND, NVT, Op); 865 assert(isa<ConstantFPSDNode>(Result) && "Didn't constant fold fp_extend?"); 866 break; 867 868 case ISD::TRUNCATE: 869 switch (getTypeAction(Node->getOperand(0).getValueType())) { 870 case Legal: 871 Result = LegalizeOp(Node->getOperand(0)); 872 assert(Result.getValueType() >= NVT && 873 "This truncation doesn't make sense!"); 874 if (Result.getValueType() > NVT) // Truncate to NVT instead of VT 875 Result = DAG.getNode(ISD::TRUNCATE, NVT, Result); 876 break; 877 case Expand: 878 assert(0 && "Cannot handle expand yet"); 879 case Promote: 880 assert(0 && "Cannot handle promote-promote yet"); 881 } 882 break; 883 case ISD::SIGN_EXTEND: 884 case ISD::ZERO_EXTEND: 885 switch (getTypeAction(Node->getOperand(0).getValueType())) { 886 case Expand: assert(0 && "BUG: Smaller reg should have been promoted!"); 887 case Legal: 888 // Input is legal? Just do extend all the way to the larger type. 889 Result = LegalizeOp(Node->getOperand(0)); 890 Result = DAG.getNode(Node->getOpcode(), NVT, Result); 891 break; 892 case Promote: 893 // Promote the reg if it's smaller. 894 Result = PromoteOp(Node->getOperand(0)); 895 // The high bits are not guaranteed to be anything. Insert an extend. 896 if (Node->getOpcode() == ISD::SIGN_EXTEND) 897 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Result, VT); 898 else 899 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Result, VT); 900 break; 901 } 902 break; 903 904 case ISD::FP_EXTEND: 905 assert(0 && "Case not implemented. Dynamically dead with 2 FP types!"); 906 case ISD::FP_ROUND: 907 switch (getTypeAction(Node->getOperand(0).getValueType())) { 908 case Expand: assert(0 && "BUG: Cannot expand FP regs!"); 909 case Promote: assert(0 && "Unreachable with 2 FP types!"); 910 case Legal: 911 // Input is legal? Do an FP_ROUND_INREG. 912 Result = LegalizeOp(Node->getOperand(0)); 913 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT); 914 break; 915 } 916 break; 917 918 case ISD::SINT_TO_FP: 919 case ISD::UINT_TO_FP: 920 switch (getTypeAction(Node->getOperand(0).getValueType())) { 921 case Legal: 922 Result = LegalizeOp(Node->getOperand(0)); 923 break; 924 925 case Promote: 926 Result = PromoteOp(Node->getOperand(0)); 927 if (Node->getOpcode() == ISD::SINT_TO_FP) 928 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(), 929 Result, Node->getOperand(0).getValueType()); 930 else 931 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, Result.getValueType(), 932 Result, Node->getOperand(0).getValueType()); 933 break; 934 case Expand: 935 assert(0 && "Unimplemented"); 936 } 937 // No extra round required here. 938 Result = DAG.getNode(Node->getOpcode(), NVT, Result); 939 break; 940 941 case ISD::FP_TO_SINT: 942 case ISD::FP_TO_UINT: 943 switch (getTypeAction(Node->getOperand(0).getValueType())) { 944 case Legal: 945 Tmp1 = LegalizeOp(Node->getOperand(0)); 946 break; 947 case Promote: 948 // The input result is prerounded, so we don't have to do anything 949 // special. 950 Tmp1 = PromoteOp(Node->getOperand(0)); 951 break; 952 case Expand: 953 assert(0 && "not implemented"); 954 } 955 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1); 956 break; 957 958 case ISD::AND: 959 case ISD::OR: 960 case ISD::XOR: 961 case ISD::ADD: 962 case ISD::SUB: 963 case ISD::MUL: 964 // The input may have strange things in the top bits of the registers, but 965 // these operations don't care. They may have wierd bits going out, but 966 // that too is okay if they are integer operations. 967 Tmp1 = PromoteOp(Node->getOperand(0)); 968 Tmp2 = PromoteOp(Node->getOperand(1)); 969 assert(Tmp1.getValueType() == NVT && Tmp2.getValueType() == NVT); 970 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2); 971 972 // However, if this is a floating point operation, they will give excess 973 // precision that we may not be able to tolerate. If we DO allow excess 974 // precision, just leave it, otherwise excise it. 975 // FIXME: Why would we need to round FP ops more than integer ones? 976 // Is Round(Add(Add(A,B),C)) != Round(Add(Round(Add(A,B)), C)) 977 if (MVT::isFloatingPoint(NVT) && NoExcessFPPrecision) 978 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT); 979 break; 980 981 case ISD::SDIV: 982 case ISD::SREM: 983 // These operators require that their input be sign extended. 984 Tmp1 = PromoteOp(Node->getOperand(0)); 985 Tmp2 = PromoteOp(Node->getOperand(1)); 986 if (MVT::isInteger(NVT)) { 987 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT); 988 Tmp2 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp2, VT); 989 } 990 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2); 991 992 // Perform FP_ROUND: this is probably overly pessimistic. 993 if (MVT::isFloatingPoint(NVT) && NoExcessFPPrecision) 994 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT); 995 break; 996 997 case ISD::UDIV: 998 case ISD::UREM: 999 // These operators require that their input be zero extended. 1000 Tmp1 = PromoteOp(Node->getOperand(0)); 1001 Tmp2 = PromoteOp(Node->getOperand(1)); 1002 assert(MVT::isInteger(NVT) && "Operators don't apply to FP!"); 1003 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT); 1004 Tmp2 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp2, VT); 1005 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2); 1006 break; 1007 1008 case ISD::SHL: 1009 Tmp1 = PromoteOp(Node->getOperand(0)); 1010 Tmp2 = LegalizeOp(Node->getOperand(1)); 1011 Result = DAG.getNode(ISD::SHL, NVT, Tmp1, Tmp2); 1012 break; 1013 case ISD::SRA: 1014 // The input value must be properly sign extended. 1015 Tmp1 = PromoteOp(Node->getOperand(0)); 1016 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT); 1017 Tmp2 = LegalizeOp(Node->getOperand(1)); 1018 Result = DAG.getNode(ISD::SRA, NVT, Tmp1, Tmp2); 1019 break; 1020 case ISD::SRL: 1021 // The input value must be properly zero extended. 1022 Tmp1 = PromoteOp(Node->getOperand(0)); 1023 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT); 1024 Tmp2 = LegalizeOp(Node->getOperand(1)); 1025 Result = DAG.getNode(ISD::SRL, NVT, Tmp1, Tmp2); 1026 break; 1027 case ISD::LOAD: 1028 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 1029 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer. 1030 Result = DAG.getNode(ISD::EXTLOAD, NVT, Tmp1, Tmp2, VT); 1031 1032 // Remember that we legalized the chain. 1033 AddLegalizedOperand(Op.getValue(1), Result.getValue(1)); 1034 break; 1035 case ISD::SELECT: 1036 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the condition 1037 Tmp2 = PromoteOp(Node->getOperand(1)); // Legalize the op0 1038 Tmp3 = PromoteOp(Node->getOperand(2)); // Legalize the op1 1039 Result = DAG.getNode(ISD::SELECT, NVT, Tmp1, Tmp2, Tmp3); 1040 break; 1041 } 1042 1043 assert(Result.Val && "Didn't set a result!"); 1044 AddPromotedOperand(Op, Result); 1045 return Result; 1046} 1047 1048/// ExpandOp - Expand the specified SDOperand into its two component pieces 1049/// Lo&Hi. Note that the Op MUST be an expanded type. As a result of this, the 1050/// LegalizeNodes map is filled in for any results that are not expanded, the 1051/// ExpandedNodes map is filled in for any results that are expanded, and the 1052/// Lo/Hi values are returned. 1053void SelectionDAGLegalize::ExpandOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi){ 1054 MVT::ValueType VT = Op.getValueType(); 1055 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT); 1056 SDNode *Node = Op.Val; 1057 assert(getTypeAction(VT) == Expand && "Not an expanded type!"); 1058 assert(MVT::isInteger(VT) && "Cannot expand FP values!"); 1059 assert(MVT::isInteger(NVT) && NVT < VT && 1060 "Cannot expand to FP value or to larger int value!"); 1061 1062 // If there is more than one use of this, see if we already expanded it. 1063 // There is no use remembering values that only have a single use, as the map 1064 // entries will never be reused. 1065 if (!Node->hasOneUse()) { 1066 std::map<SDOperand, std::pair<SDOperand, SDOperand> >::iterator I 1067 = ExpandedNodes.find(Op); 1068 if (I != ExpandedNodes.end()) { 1069 Lo = I->second.first; 1070 Hi = I->second.second; 1071 return; 1072 } 1073 } 1074 1075 // Expanding to multiple registers needs to perform an optimization step, and 1076 // is not careful to avoid operations the target does not support. Make sure 1077 // that all generated operations are legalized in the next iteration. 1078 NeedsAnotherIteration = true; 1079 const char *LibCallName = 0; 1080 1081 switch (Node->getOpcode()) { 1082 default: 1083 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n"; 1084 assert(0 && "Do not know how to expand this operator!"); 1085 abort(); 1086 case ISD::Constant: { 1087 uint64_t Cst = cast<ConstantSDNode>(Node)->getValue(); 1088 Lo = DAG.getConstant(Cst, NVT); 1089 Hi = DAG.getConstant(Cst >> MVT::getSizeInBits(NVT), NVT); 1090 break; 1091 } 1092 1093 case ISD::CopyFromReg: { 1094 unsigned Reg = cast<RegSDNode>(Node)->getReg(); 1095 // Aggregate register values are always in consequtive pairs. 1096 Lo = DAG.getCopyFromReg(Reg, NVT, Node->getOperand(0)); 1097 Hi = DAG.getCopyFromReg(Reg+1, NVT, Lo.getValue(1)); 1098 1099 // Remember that we legalized the chain. 1100 AddLegalizedOperand(Op.getValue(1), Hi.getValue(1)); 1101 1102 assert(isTypeLegal(NVT) && "Cannot expand this multiple times yet!"); 1103 break; 1104 } 1105 1106 case ISD::LOAD: { 1107 SDOperand Ch = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 1108 SDOperand Ptr = LegalizeOp(Node->getOperand(1)); // Legalize the pointer. 1109 Lo = DAG.getLoad(NVT, Ch, Ptr); 1110 1111 // Increment the pointer to the other half. 1112 unsigned IncrementSize = MVT::getSizeInBits(Lo.getValueType())/8; 1113 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr, 1114 getIntPtrConstant(IncrementSize)); 1115 // FIXME: This load is independent of the first one. 1116 Hi = DAG.getLoad(NVT, Lo.getValue(1), Ptr); 1117 1118 // Remember that we legalized the chain. 1119 AddLegalizedOperand(Op.getValue(1), Hi.getValue(1)); 1120 if (!TLI.isLittleEndian()) 1121 std::swap(Lo, Hi); 1122 break; 1123 } 1124 case ISD::CALL: { 1125 SDOperand Chain = LegalizeOp(Node->getOperand(0)); // Legalize the chain. 1126 SDOperand Callee = LegalizeOp(Node->getOperand(1)); // Legalize the callee. 1127 1128 assert(Node->getNumValues() == 2 && Op.ResNo == 0 && 1129 "Can only expand a call once so far, not i64 -> i16!"); 1130 1131 std::vector<MVT::ValueType> RetTyVTs; 1132 RetTyVTs.reserve(3); 1133 RetTyVTs.push_back(NVT); 1134 RetTyVTs.push_back(NVT); 1135 RetTyVTs.push_back(MVT::Other); 1136 SDNode *NC = DAG.getCall(RetTyVTs, Chain, Callee); 1137 Lo = SDOperand(NC, 0); 1138 Hi = SDOperand(NC, 1); 1139 1140 // Insert the new chain mapping. 1141 AddLegalizedOperand(Op.getValue(1), Hi.getValue(2)); 1142 break; 1143 } 1144 case ISD::AND: 1145 case ISD::OR: 1146 case ISD::XOR: { // Simple logical operators -> two trivial pieces. 1147 SDOperand LL, LH, RL, RH; 1148 ExpandOp(Node->getOperand(0), LL, LH); 1149 ExpandOp(Node->getOperand(1), RL, RH); 1150 Lo = DAG.getNode(Node->getOpcode(), NVT, LL, RL); 1151 Hi = DAG.getNode(Node->getOpcode(), NVT, LH, RH); 1152 break; 1153 } 1154 case ISD::SELECT: { 1155 SDOperand C, LL, LH, RL, RH; 1156 // FIXME: BOOLS MAY REQUIRE PROMOTION! 1157 C = LegalizeOp(Node->getOperand(0)); 1158 ExpandOp(Node->getOperand(1), LL, LH); 1159 ExpandOp(Node->getOperand(2), RL, RH); 1160 Lo = DAG.getNode(ISD::SELECT, NVT, C, LL, RL); 1161 Hi = DAG.getNode(ISD::SELECT, NVT, C, LH, RH); 1162 break; 1163 } 1164 case ISD::SIGN_EXTEND: { 1165 // The low part is just a sign extension of the input (which degenerates to 1166 // a copy). 1167 Lo = DAG.getNode(ISD::SIGN_EXTEND, NVT, LegalizeOp(Node->getOperand(0))); 1168 1169 // The high part is obtained by SRA'ing all but one of the bits of the lo 1170 // part. 1171 unsigned LoSize = MVT::getSizeInBits(Lo.getValueType()); 1172 Hi = DAG.getNode(ISD::SRA, NVT, Lo, DAG.getConstant(LoSize-1, MVT::i8)); 1173 break; 1174 } 1175 case ISD::ZERO_EXTEND: 1176 // The low part is just a zero extension of the input (which degenerates to 1177 // a copy). 1178 Lo = DAG.getNode(ISD::ZERO_EXTEND, NVT, LegalizeOp(Node->getOperand(0))); 1179 1180 // The high part is just a zero. 1181 Hi = DAG.getConstant(0, NVT); 1182 break; 1183 1184 // These operators cannot be expanded directly, emit them as calls to 1185 // library functions. 1186 case ISD::FP_TO_SINT: 1187 if (Node->getOperand(0).getValueType() == MVT::f32) 1188 LibCallName = "__fixsfdi"; 1189 else 1190 LibCallName = "__fixdfdi"; 1191 break; 1192 case ISD::FP_TO_UINT: 1193 if (Node->getOperand(0).getValueType() == MVT::f32) 1194 LibCallName = "__fixunssfdi"; 1195 else 1196 LibCallName = "__fixunsdfdi"; 1197 break; 1198 1199 case ISD::ADD: LibCallName = "__adddi3"; break; 1200 case ISD::SUB: LibCallName = "__subdi3"; break; 1201 case ISD::MUL: LibCallName = "__muldi3"; break; 1202 case ISD::SDIV: LibCallName = "__divdi3"; break; 1203 case ISD::UDIV: LibCallName = "__udivdi3"; break; 1204 case ISD::SREM: LibCallName = "__moddi3"; break; 1205 case ISD::UREM: LibCallName = "__umoddi3"; break; 1206 case ISD::SHL: LibCallName = "__ashldi3"; break; 1207 case ISD::SRA: LibCallName = "__ashrdi3"; break; 1208 case ISD::SRL: LibCallName = "__lshrdi3"; break; 1209 } 1210 1211 // Int2FP -> __floatdisf/__floatdidf 1212 1213 // If this is to be expanded into a libcall... do so now. 1214 if (LibCallName) { 1215 TargetLowering::ArgListTy Args; 1216 for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) 1217 Args.push_back(std::make_pair(Node->getOperand(i), 1218 MVT::getTypeForValueType(Node->getOperand(i).getValueType()))); 1219 SDOperand Callee = DAG.getExternalSymbol(LibCallName, TLI.getPointerTy()); 1220 1221 // We don't care about token chains for libcalls. We just use the entry 1222 // node as our input and ignore the output chain. This allows us to place 1223 // calls wherever we need them to satisfy data dependences. 1224 SDOperand Result = TLI.LowerCallTo(DAG.getEntryNode(), 1225 MVT::getTypeForValueType(Op.getValueType()), Callee, 1226 Args, DAG).first; 1227 ExpandOp(Result, Lo, Hi); 1228 } 1229 1230 // Remember in a map if the values will be reused later. 1231 if (!Node->hasOneUse()) { 1232 bool isNew = ExpandedNodes.insert(std::make_pair(Op, 1233 std::make_pair(Lo, Hi))).second; 1234 assert(isNew && "Value already expanded?!?"); 1235 } 1236} 1237 1238 1239// SelectionDAG::Legalize - This is the entry point for the file. 1240// 1241void SelectionDAG::Legalize(TargetLowering &TLI) { 1242 /// run - This is the main entry point to this class. 1243 /// 1244 SelectionDAGLegalize(TLI, *this).Run(); 1245} 1246 1247