1 //===-- LegalizeDAG.cpp - Implement SelectionDAG::Legalize ----------------===//
3 // The LLVM Compiler Infrastructure
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.
8 //===----------------------------------------------------------------------===//
10 // This file implements the SelectionDAG::Legalize method.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/CodeGen/SelectionDAG.h"
15 #include "llvm/CodeGen/MachineConstantPool.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/Target/TargetLowering.h"
18 #include "llvm/Constants.h"
22 //===----------------------------------------------------------------------===//
23 /// SelectionDAGLegalize - This takes an arbitrary SelectionDAG as input and
24 /// hacks on it until the target machine can handle it. This involves
25 /// eliminating value sizes the machine cannot handle (promoting small sizes to
26 /// large sizes or splitting up large values into small values) as well as
27 /// eliminating operations the machine cannot handle.
29 /// This code also does a small amount of optimization and recognition of idioms
30 /// as part of its processing. For example, if a target does not support a
31 /// 'setcc' instruction efficiently, but does support 'brcc' instruction, this
32 /// will attempt merge setcc and brc instructions into brcc's.
35 class SelectionDAGLegalize {
39 /// LegalizeAction - This enum indicates what action we should take for each
40 /// value type the can occur in the program.
42 Legal, // The target natively supports this value type.
43 Promote, // This should be promoted to the next larger type.
44 Expand, // This integer type should be broken into smaller pieces.
47 /// TransformToType - For any value types we are promoting or expanding, this
48 /// contains the value type that we are changing to. For Expanded types, this
49 /// contains one step of the expand (e.g. i64 -> i32), even if there are
50 /// multiple steps required (e.g. i64 -> i16)
51 MVT::ValueType TransformToType[MVT::LAST_VALUETYPE];
53 /// ValueTypeActions - This is a bitvector that contains two bits for each
54 /// value type, where the two bits correspond to the LegalizeAction enum.
55 /// This can be queried with "getTypeAction(VT)".
56 unsigned ValueTypeActions;
58 /// NeedsAnotherIteration - This is set when we expand a large integer
59 /// operation into smaller integer operations, but the smaller operations are
60 /// not set. This occurs only rarely in practice, for targets that don't have
61 /// 32-bit or larger integer registers.
62 bool NeedsAnotherIteration;
64 /// LegalizedNodes - For nodes that are of legal width, and that have more
65 /// than one use, this map indicates what regularized operand to use. This
66 /// allows us to avoid legalizing the same thing more than once.
67 std::map<SDOperand, SDOperand> LegalizedNodes;
69 /// ExpandedNodes - For nodes that need to be expanded, and which have more
70 /// than one use, this map indicates which which operands are the expanded
71 /// version of the input. This allows us to avoid expanding the same node
73 std::map<SDOperand, std::pair<SDOperand, SDOperand> > ExpandedNodes;
75 void AddLegalizedOperand(SDOperand From, SDOperand To) {
76 bool isNew = LegalizedNodes.insert(std::make_pair(From, To)).second;
77 assert(isNew && "Got into the map somehow?");
80 /// setValueTypeAction - Set the action for a particular value type. This
81 /// assumes an action has not already been set for this value type.
82 void setValueTypeAction(MVT::ValueType VT, LegalizeAction A) {
83 ValueTypeActions |= A << (VT*2);
85 MVT::ValueType PromoteTo;
89 unsigned LargerReg = VT+1;
90 while (!TLI.hasNativeSupportFor((MVT::ValueType)LargerReg)) {
92 assert(MVT::isInteger((MVT::ValueType)LargerReg) &&
93 "Nothing to promote to??");
95 PromoteTo = (MVT::ValueType)LargerReg;
98 assert(MVT::isInteger(VT) == MVT::isInteger(PromoteTo) &&
99 MVT::isFloatingPoint(VT) == MVT::isFloatingPoint(PromoteTo) &&
100 "Can only promote from int->int or fp->fp!");
101 assert(VT < PromoteTo && "Must promote to a larger type!");
102 TransformToType[VT] = PromoteTo;
103 } else if (A == Expand) {
104 assert(MVT::isInteger(VT) && VT > MVT::i8 &&
105 "Cannot expand this type: target must support SOME integer reg!");
106 // Expand to the next smaller integer type!
107 TransformToType[VT] = (MVT::ValueType)(VT-1);
113 SelectionDAGLegalize(TargetLowering &TLI, SelectionDAG &DAG);
115 /// Run - While there is still lowering to do, perform a pass over the DAG.
116 /// Most regularization can be done in a single pass, but targets that require
117 /// large values to be split into registers multiple times (e.g. i64 -> 4x
118 /// i16) require iteration for these values (the first iteration will demote
119 /// to i32, the second will demote to i16).
122 NeedsAnotherIteration = false;
124 } while (NeedsAnotherIteration);
127 /// getTypeAction - Return how we should legalize values of this type, either
128 /// it is already legal or we need to expand it into multiple registers of
129 /// smaller integer type, or we need to promote it to a larger type.
130 LegalizeAction getTypeAction(MVT::ValueType VT) const {
131 return (LegalizeAction)((ValueTypeActions >> (2*VT)) & 3);
134 /// isTypeLegal - Return true if this type is legal on this target.
136 bool isTypeLegal(MVT::ValueType VT) const {
137 return getTypeAction(VT) == Legal;
143 SDOperand LegalizeOp(SDOperand O);
144 void ExpandOp(SDOperand O, SDOperand &Lo, SDOperand &Hi);
146 SDOperand getIntPtrConstant(uint64_t Val) {
147 return DAG.getConstant(Val, TLI.getPointerTy());
153 SelectionDAGLegalize::SelectionDAGLegalize(TargetLowering &tli,
155 : TLI(tli), DAG(dag), ValueTypeActions(0) {
157 assert(MVT::LAST_VALUETYPE <= 16 &&
158 "Too many value types for ValueTypeActions to hold!");
160 // Inspect all of the ValueType's possible, deciding how to process them.
161 for (unsigned IntReg = MVT::i1; IntReg <= MVT::i128; ++IntReg)
162 // If TLI says we are expanding this type, expand it!
163 if (TLI.getNumElements((MVT::ValueType)IntReg) != 1)
164 setValueTypeAction((MVT::ValueType)IntReg, Expand);
165 else if (!TLI.hasNativeSupportFor((MVT::ValueType)IntReg))
166 // Otherwise, if we don't have native support, we must promote to a
168 setValueTypeAction((MVT::ValueType)IntReg, Promote);
170 // If the target does not have native support for F32, promote it to F64.
171 if (!TLI.hasNativeSupportFor(MVT::f32))
172 setValueTypeAction(MVT::f32, Promote);
175 void SelectionDAGLegalize::LegalizeDAG() {
176 SDOperand OldRoot = DAG.getRoot();
177 SDOperand NewRoot = LegalizeOp(OldRoot);
178 DAG.setRoot(NewRoot);
180 ExpandedNodes.clear();
181 LegalizedNodes.clear();
183 // Remove dead nodes now.
184 DAG.RemoveDeadNodes(OldRoot.Val);
187 SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
188 // If this operation defines any values that cannot be represented in a
189 // register on this target, make sure to expand it.
190 if (Op.Val->getNumValues() == 1) {// Fast path == assertion only
191 assert(getTypeAction(Op.Val->getValueType(0)) == Legal &&
192 "For a single use value, caller should check for legality!");
194 for (unsigned i = 0, e = Op.Val->getNumValues(); i != e; ++i)
195 switch (getTypeAction(Op.Val->getValueType(i))) {
196 case Legal: break; // Nothing to do.
199 ExpandOp(Op.getValue(i), T1, T2);
200 assert(LegalizedNodes.count(Op) &&
201 "Expansion didn't add legal operands!");
202 return LegalizedNodes[Op];
205 // FIXME: Implement promotion!
206 assert(0 && "Promotion not implemented at all yet!");
210 // If there is more than one use of this, see if we already legalized it.
211 // There is no use remembering values that only have a single use, as the map
212 // entries will never be reused.
213 if (!Op.Val->hasOneUse()) {
214 std::map<SDOperand, SDOperand>::iterator I = LegalizedNodes.find(Op);
215 if (I != LegalizedNodes.end()) return I->second;
218 SDOperand Tmp1, Tmp2;
220 SDOperand Result = Op;
221 SDNode *Node = Op.Val;
222 LegalizeAction Action;
224 switch (Node->getOpcode()) {
226 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n";
227 assert(0 && "Do not know how to legalize this operator!");
229 case ISD::EntryToken:
230 case ISD::FrameIndex:
231 case ISD::GlobalAddress:
232 case ISD::ExternalSymbol:
233 case ISD::ConstantPool:
234 case ISD::CopyFromReg: // Nothing to do.
235 assert(getTypeAction(Node->getValueType(0)) == Legal &&
236 "This must be legal!");
239 // We know we don't need to expand constants here, constants only have one
240 // value and we check that it is fine above.
242 // FIXME: Maybe we should handle things like targets that don't support full
243 // 32-bit immediates?
245 case ISD::ConstantFP: {
246 // Spill FP immediates to the constant pool if the target cannot directly
247 // codegen them. Targets often have some immediate values that can be
248 // efficiently generated into an FP register without a load. We explicitly
249 // leave these constants as ConstantFP nodes for the target to deal with.
251 ConstantFPSDNode *CFP = cast<ConstantFPSDNode>(Node);
253 // Check to see if this FP immediate is already legal.
254 bool isLegal = false;
255 for (TargetLowering::legal_fpimm_iterator I = TLI.legal_fpimm_begin(),
256 E = TLI.legal_fpimm_end(); I != E; ++I)
257 if (CFP->isExactlyValue(*I)) {
263 // Otherwise we need to spill the constant to memory.
264 MachineConstantPool *CP = DAG.getMachineFunction().getConstantPool();
268 // If a FP immediate is precise when represented as a float, we put it
269 // into the constant pool as a float, even if it's is statically typed
271 MVT::ValueType VT = CFP->getValueType(0);
272 bool isDouble = VT == MVT::f64;
273 ConstantFP *LLVMC = ConstantFP::get(isDouble ? Type::DoubleTy :
274 Type::FloatTy, CFP->getValue());
275 if (isDouble && CFP->isExactlyValue((float)CFP->getValue())) {
276 LLVMC = cast<ConstantFP>(ConstantExpr::getCast(LLVMC, Type::FloatTy));
281 SDOperand CPIdx = DAG.getConstantPool(CP->getConstantPoolIndex(LLVMC),
283 Result = DAG.getLoad(VT, DAG.getEntryNode(), CPIdx);
285 if (Extend) Result = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Result);
289 case ISD::ADJCALLSTACKDOWN:
290 case ISD::ADJCALLSTACKUP:
291 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
292 // There is no need to legalize the size argument (Operand #1)
293 if (Tmp1 != Node->getOperand(0))
294 Result = DAG.getNode(Node->getOpcode(), MVT::Other, Tmp1,
295 Node->getOperand(1));
298 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
299 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the callee.
300 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1)) {
301 std::vector<MVT::ValueType> RetTyVTs;
302 RetTyVTs.reserve(Node->getNumValues());
303 for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i)
304 RetTyVTs.push_back(Node->getValueType(i));
305 Result = SDOperand(DAG.getCall(RetTyVTs, Tmp1, Tmp2), Op.ResNo);
310 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
311 if (Tmp1 != Node->getOperand(0))
312 Result = DAG.getNode(ISD::BR, MVT::Other, Tmp1, Node->getOperand(1));
316 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
317 // FIXME: booleans might not be legal!
318 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the condition.
319 // Basic block destination (Op#2) is always legal.
320 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
321 Result = DAG.getNode(ISD::BRCOND, MVT::Other, Tmp1, Tmp2,
322 Node->getOperand(2));
326 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
327 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer.
328 if (Tmp1 != Node->getOperand(0) ||
329 Tmp2 != Node->getOperand(1))
330 Result = DAG.getLoad(Node->getValueType(0), Tmp1, Tmp2);
332 Result = SDOperand(Node, 0);
334 // Since loads produce two values, make sure to remember that we legalized
336 AddLegalizedOperand(SDOperand(Node, 0), Result);
337 AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1));
338 return Result.getValue(Op.ResNo);
340 case ISD::EXTRACT_ELEMENT:
341 // Get both the low and high parts.
342 ExpandOp(Node->getOperand(0), Tmp1, Tmp2);
343 if (cast<ConstantSDNode>(Node->getOperand(1))->getValue())
344 Result = Tmp2; // 1 -> Hi
346 Result = Tmp1; // 0 -> Lo
350 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
352 switch (getTypeAction(Node->getOperand(1).getValueType())) {
354 // Legalize the incoming value (must be legal).
355 Tmp2 = LegalizeOp(Node->getOperand(1));
356 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
357 Result = DAG.getCopyToReg(Tmp1, Tmp2,
358 cast<CopyRegSDNode>(Node)->getReg());
362 ExpandOp(Node->getOperand(1), Lo, Hi);
363 unsigned Reg = cast<CopyRegSDNode>(Node)->getReg();
364 Result = DAG.getCopyToReg(Tmp1, Lo, Reg);
365 Result = DAG.getCopyToReg(Result, Hi, Reg+1);
366 assert(isTypeLegal(Result.getValueType()) &&
367 "Cannot expand multiple times yet (i64 -> i16)");
371 assert(0 && "Don't know what it means to promote this!");
377 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
378 switch (Node->getNumOperands()) {
380 switch (getTypeAction(Node->getOperand(1).getValueType())) {
382 Tmp2 = LegalizeOp(Node->getOperand(1));
383 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
384 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Tmp2);
388 ExpandOp(Node->getOperand(1), Lo, Hi);
389 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Lo, Hi);
393 assert(0 && "Can't promote return value!");
397 if (Tmp1 != Node->getOperand(0))
398 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1);
400 default: { // ret <values>
401 std::vector<SDOperand> NewValues;
402 NewValues.push_back(Tmp1);
403 for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i)
404 switch (getTypeAction(Node->getOperand(i).getValueType())) {
406 NewValues.push_back(LegalizeOp(Node->getOperand(1)));
410 ExpandOp(Node->getOperand(i), Lo, Hi);
411 NewValues.push_back(Lo);
412 NewValues.push_back(Hi);
416 assert(0 && "Can't promote return value!");
418 Result = DAG.getNode(ISD::RET, MVT::Other, NewValues);
424 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
425 Tmp2 = LegalizeOp(Node->getOperand(2)); // Legalize the pointer.
427 switch (getTypeAction(Node->getOperand(1).getValueType())) {
429 SDOperand Val = LegalizeOp(Node->getOperand(1));
430 if (Val != Node->getOperand(1) || Tmp1 != Node->getOperand(0) ||
431 Tmp2 != Node->getOperand(2))
432 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Val, Tmp2);
436 assert(0 && "FIXME: promote for stores not implemented!");
439 ExpandOp(Node->getOperand(1), Lo, Hi);
441 if (!TLI.isLittleEndian())
444 // FIXME: These two stores are independent of each other!
445 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Lo, Tmp2);
447 unsigned IncrementSize;
448 switch (Lo.getValueType()) {
449 default: assert(0 && "Unknown ValueType to expand to!");
450 case MVT::i32: IncrementSize = 4; break;
451 case MVT::i16: IncrementSize = 2; break;
452 case MVT::i8: IncrementSize = 1; break;
454 Tmp2 = DAG.getNode(ISD::ADD, Tmp2.getValueType(), Tmp2,
455 getIntPtrConstant(IncrementSize));
456 assert(isTypeLegal(Tmp2.getValueType()) &&
457 "Pointers must be legal!");
458 Result = DAG.getNode(ISD::STORE, MVT::Other, Result, Hi, Tmp2);
462 // FIXME: BOOLS MAY REQUIRE PROMOTION!
463 Tmp1 = LegalizeOp(Node->getOperand(0)); // Cond
464 Tmp2 = LegalizeOp(Node->getOperand(1)); // TrueVal
465 SDOperand Tmp3 = LegalizeOp(Node->getOperand(2)); // FalseVal
467 if (Tmp1 != Node->getOperand(0) ||
468 Tmp2 != Node->getOperand(1) ||
469 Tmp3 != Node->getOperand(2))
470 Result = DAG.getNode(ISD::SELECT, Node->getValueType(0), Tmp1, Tmp2,Tmp3);
474 switch (getTypeAction(Node->getOperand(0).getValueType())) {
476 Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS
477 Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS
478 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
479 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
483 assert(0 && "Can't promote setcc operands yet!");
486 SDOperand LHSLo, LHSHi, RHSLo, RHSHi;
487 ExpandOp(Node->getOperand(0), LHSLo, LHSHi);
488 ExpandOp(Node->getOperand(1), RHSLo, RHSHi);
489 switch (cast<SetCCSDNode>(Node)->getCondition()) {
492 Tmp1 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSLo, RHSLo);
493 Tmp2 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSHi, RHSHi);
494 Tmp1 = DAG.getNode(ISD::OR, Tmp1.getValueType(), Tmp1, Tmp2);
495 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(), Tmp1,
496 DAG.getConstant(0, Tmp1.getValueType()));
499 // FIXME: This generated code sucks.
501 switch (cast<SetCCSDNode>(Node)->getCondition()) {
502 default: assert(0 && "Unknown integer setcc!");
504 case ISD::SETULT: LowCC = ISD::SETULT; break;
506 case ISD::SETUGT: LowCC = ISD::SETUGT; break;
508 case ISD::SETULE: LowCC = ISD::SETULE; break;
510 case ISD::SETUGE: LowCC = ISD::SETUGE; break;
513 // Tmp1 = lo(op1) < lo(op2) // Always unsigned comparison
514 // Tmp2 = hi(op1) < hi(op2) // Signedness depends on operands
515 // dest = hi(op1) == hi(op2) ? Tmp1 : Tmp2;
517 // NOTE: on targets without efficient SELECT of bools, we can always use
518 // this identity: (B1 ? B2 : B3) --> (B1 & B2)|(!B1&B3)
519 Tmp1 = DAG.getSetCC(LowCC, LHSLo, RHSLo);
520 Tmp2 = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
522 Result = DAG.getSetCC(ISD::SETEQ, LHSHi, RHSHi);
523 Result = DAG.getNode(ISD::SELECT, MVT::i1, Result, Tmp1, Tmp2);
542 Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS
543 Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS
544 if (Tmp1 != Node->getOperand(0) ||
545 Tmp2 != Node->getOperand(1))
546 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1,Tmp2);
548 case ISD::ZERO_EXTEND:
549 case ISD::SIGN_EXTEND:
553 switch (getTypeAction(Node->getOperand(0).getValueType())) {
555 Tmp1 = LegalizeOp(Node->getOperand(0));
556 if (Tmp1 != Node->getOperand(0))
557 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1);
560 // In the expand case, we must be dealing with a truncate, because
561 // otherwise the result would be larger than the source.
562 assert(Node->getOpcode() == ISD::TRUNCATE &&
563 "Shouldn't need to expand other operators here!");
564 ExpandOp(Node->getOperand(0), Tmp1, Tmp2);
566 // Since the result is legal, we should just be able to truncate the low
567 // part of the source.
568 Result = DAG.getNode(ISD::TRUNCATE, Node->getValueType(0), Tmp1);
572 assert(0 && "Do not know how to promote this yet!");
577 if (!Op.Val->hasOneUse())
578 AddLegalizedOperand(Op, Result);
584 /// ExpandOp - Expand the specified SDOperand into its two component pieces
585 /// Lo&Hi. Note that the Op MUST be an expanded type. As a result of this, the
586 /// LegalizeNodes map is filled in for any results that are not expanded, the
587 /// ExpandedNodes map is filled in for any results that are expanded, and the
588 /// Lo/Hi values are returned.
589 void SelectionDAGLegalize::ExpandOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi){
590 MVT::ValueType VT = Op.getValueType();
591 MVT::ValueType NVT = TransformToType[VT];
592 SDNode *Node = Op.Val;
593 assert(getTypeAction(VT) == Expand && "Not an expanded type!");
594 assert(MVT::isInteger(VT) && "Cannot expand FP values!");
595 assert(MVT::isInteger(NVT) && NVT < VT &&
596 "Cannot expand to FP value or to larger int value!");
598 // If there is more than one use of this, see if we already expanded it.
599 // There is no use remembering values that only have a single use, as the map
600 // entries will never be reused.
601 if (!Node->hasOneUse()) {
602 std::map<SDOperand, std::pair<SDOperand, SDOperand> >::iterator I
603 = ExpandedNodes.find(Op);
604 if (I != ExpandedNodes.end()) {
605 Lo = I->second.first;
606 Hi = I->second.second;
611 // If we are lowering to a type that the target doesn't support, we will have
612 // to iterate lowering.
613 if (!isTypeLegal(NVT))
614 NeedsAnotherIteration = true;
616 LegalizeAction Action;
617 switch (Node->getOpcode()) {
619 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n";
620 assert(0 && "Do not know how to expand this operator!");
622 case ISD::Constant: {
623 uint64_t Cst = cast<ConstantSDNode>(Node)->getValue();
624 Lo = DAG.getConstant(Cst, NVT);
625 Hi = DAG.getConstant(Cst >> MVT::getSizeInBits(NVT), NVT);
629 case ISD::CopyFromReg: {
630 unsigned Reg = cast<CopyRegSDNode>(Node)->getReg();
631 // Aggregate register values are always in consequtive pairs.
632 Lo = DAG.getCopyFromReg(Reg, NVT);
633 Hi = DAG.getCopyFromReg(Reg+1, NVT);
634 assert(isTypeLegal(NVT) && "Cannot expand this multiple times yet!");
639 SDOperand Ch = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
640 SDOperand Ptr = LegalizeOp(Node->getOperand(1)); // Legalize the pointer.
641 Lo = DAG.getLoad(NVT, Ch, Ptr);
643 // Increment the pointer to the other half.
644 unsigned IncrementSize;
645 switch (Lo.getValueType()) {
646 default: assert(0 && "Unknown ValueType to expand to!");
647 case MVT::i32: IncrementSize = 4; break;
648 case MVT::i16: IncrementSize = 2; break;
649 case MVT::i8: IncrementSize = 1; break;
651 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
652 getIntPtrConstant(IncrementSize));
653 // FIXME: This load is independent of the first one.
654 Hi = DAG.getLoad(NVT, Lo.getValue(1), Ptr);
656 // Remember that we legalized the chain.
657 AddLegalizedOperand(Op.getValue(1), Hi.getValue(1));
658 if (!TLI.isLittleEndian())
663 SDOperand Chain = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
664 SDOperand Callee = LegalizeOp(Node->getOperand(1)); // Legalize the callee.
666 assert(Node->getNumValues() == 2 && Op.ResNo == 0 &&
667 "Can only expand a call once so far, not i64 -> i16!");
669 std::vector<MVT::ValueType> RetTyVTs;
671 RetTyVTs.push_back(NVT);
672 RetTyVTs.push_back(NVT);
673 RetTyVTs.push_back(MVT::Other);
674 SDNode *NC = DAG.getCall(RetTyVTs, Chain, Callee);
675 Lo = SDOperand(NC, 0);
676 Hi = SDOperand(NC, 1);
678 // Insert the new chain mapping.
679 bool isNew = LegalizedNodes.insert(std::make_pair(Op.getValue(1),
680 Hi.getValue(2))).second;
681 assert(isNew && "This node was already legalized!");
686 case ISD::XOR: { // Simple logical operators -> two trivial pieces.
687 SDOperand LL, LH, RL, RH;
688 ExpandOp(Node->getOperand(0), LL, LH);
689 ExpandOp(Node->getOperand(1), RL, RH);
690 Lo = DAG.getNode(Node->getOpcode(), NVT, LL, RL);
691 Hi = DAG.getNode(Node->getOpcode(), NVT, LH, RH);
695 SDOperand C, LL, LH, RL, RH;
696 // FIXME: BOOLS MAY REQUIRE PROMOTION!
697 C = LegalizeOp(Node->getOperand(0));
698 ExpandOp(Node->getOperand(1), LL, LH);
699 ExpandOp(Node->getOperand(2), RL, RH);
700 Lo = DAG.getNode(ISD::SELECT, NVT, C, LL, RL);
701 Hi = DAG.getNode(ISD::SELECT, NVT, C, LH, RH);
704 case ISD::SIGN_EXTEND: {
705 // The low part is just a sign extension of the input (which degenerates to
707 Lo = DAG.getNode(ISD::SIGN_EXTEND, NVT, LegalizeOp(Node->getOperand(0)));
709 // The high part is obtained by SRA'ing all but one of the bits of the lo
711 unsigned SrcSize = MVT::getSizeInBits(Node->getOperand(0).getValueType());
712 Hi = DAG.getNode(ISD::SRA, NVT, Lo, DAG.getConstant(SrcSize-1, MVT::i8));
715 case ISD::ZERO_EXTEND:
716 // The low part is just a zero extension of the input (which degenerates to
718 Lo = DAG.getNode(ISD::ZERO_EXTEND, NVT, LegalizeOp(Node->getOperand(0)));
720 // The high part is just a zero.
721 Hi = DAG.getConstant(0, NVT);
725 // Remember in a map if the values will be reused later.
726 if (!Node->hasOneUse()) {
727 bool isNew = ExpandedNodes.insert(std::make_pair(Op,
728 std::make_pair(Lo, Hi))).second;
729 assert(isNew && "Value already expanded?!?");
734 // SelectionDAG::Legalize - This is the entry point for the file.
736 void SelectionDAG::Legalize(TargetLowering &TLI) {
737 /// run - This is the main entry point to this class.
739 SelectionDAGLegalize(TLI, *this).Run();