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/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"
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.
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.
38 class SelectionDAGLegalize {
42 /// LegalizeAction - This enum indicates what action we should take for each
43 /// value type the can occur in the program.
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.
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;
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;
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;
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;
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
75 std::map<SDOperand, std::pair<SDOperand, SDOperand> > ExpandedNodes;
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?");
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?");
88 SelectionDAGLegalize(SelectionDAG &DAG);
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).
97 NeedsAnotherIteration = false;
99 } while (NeedsAnotherIteration);
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);
109 /// isTypeLegal - Return true if this type is legal on this target.
111 bool isTypeLegal(MVT::ValueType VT) const {
112 return getTypeAction(VT) == Legal;
118 SDOperand LegalizeOp(SDOperand O);
119 void ExpandOp(SDOperand O, SDOperand &Lo, SDOperand &Hi);
120 SDOperand PromoteOp(SDOperand O);
122 SDOperand ExpandLibCall(const char *Name, SDNode *Node,
124 SDOperand ExpandIntToFP(bool isSigned, MVT::ValueType DestTy,
126 bool ExpandShift(unsigned Opc, SDOperand Op, SDOperand Amt,
127 SDOperand &Lo, SDOperand &Hi);
128 void ExpandAddSub(bool isAdd, SDOperand Op, SDOperand Amt,
129 SDOperand &Lo, SDOperand &Hi);
131 SDOperand getIntPtrConstant(uint64_t Val) {
132 return DAG.getConstant(Val, TLI.getPointerTy());
138 SelectionDAGLegalize::SelectionDAGLegalize(SelectionDAG &dag)
139 : TLI(dag.getTargetLoweringInfo()), DAG(dag),
140 ValueTypeActions(TLI.getValueTypeActions()) {
141 assert(MVT::LAST_VALUETYPE <= 16 &&
142 "Too many value types for ValueTypeActions to hold!");
145 void SelectionDAGLegalize::LegalizeDAG() {
146 SDOperand OldRoot = DAG.getRoot();
147 SDOperand NewRoot = LegalizeOp(OldRoot);
148 DAG.setRoot(NewRoot);
150 ExpandedNodes.clear();
151 LegalizedNodes.clear();
152 PromotedNodes.clear();
154 // Remove dead nodes now.
155 DAG.RemoveDeadNodes(OldRoot.Val);
158 SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
159 assert(getTypeAction(Op.getValueType()) == Legal &&
160 "Caller should expand or promote operands that are not legal!");
162 // If this operation defines any values that cannot be represented in a
163 // register on this target, make sure to expand or promote them.
164 if (Op.Val->getNumValues() > 1) {
165 for (unsigned i = 0, e = Op.Val->getNumValues(); i != e; ++i)
166 switch (getTypeAction(Op.Val->getValueType(i))) {
167 case Legal: break; // Nothing to do.
170 ExpandOp(Op.getValue(i), T1, T2);
171 assert(LegalizedNodes.count(Op) &&
172 "Expansion didn't add legal operands!");
173 return LegalizedNodes[Op];
176 PromoteOp(Op.getValue(i));
177 assert(LegalizedNodes.count(Op) &&
178 "Expansion didn't add legal operands!");
179 return LegalizedNodes[Op];
183 std::map<SDOperand, SDOperand>::iterator I = LegalizedNodes.find(Op);
184 if (I != LegalizedNodes.end()) return I->second;
186 SDOperand Tmp1, Tmp2, Tmp3;
188 SDOperand Result = Op;
189 SDNode *Node = Op.Val;
191 switch (Node->getOpcode()) {
193 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n";
194 assert(0 && "Do not know how to legalize this operator!");
196 case ISD::EntryToken:
197 case ISD::FrameIndex:
198 case ISD::GlobalAddress:
199 case ISD::ExternalSymbol:
200 case ISD::ConstantPool: // Nothing to do.
201 assert(getTypeAction(Node->getValueType(0)) == Legal &&
202 "This must be legal!");
204 case ISD::CopyFromReg:
205 Tmp1 = LegalizeOp(Node->getOperand(0));
206 if (Tmp1 != Node->getOperand(0))
207 Result = DAG.getCopyFromReg(cast<RegSDNode>(Node)->getReg(),
208 Node->getValueType(0), Tmp1);
210 Result = Op.getValue(0);
212 // Since CopyFromReg produces two values, make sure to remember that we
213 // legalized both of them.
214 AddLegalizedOperand(Op.getValue(0), Result);
215 AddLegalizedOperand(Op.getValue(1), Result.getValue(1));
216 return Result.getValue(Op.ResNo);
217 case ISD::ImplicitDef:
218 Tmp1 = LegalizeOp(Node->getOperand(0));
219 if (Tmp1 != Node->getOperand(0))
220 Result = DAG.getImplicitDef(Tmp1, cast<RegSDNode>(Node)->getReg());
223 // We know we don't need to expand constants here, constants only have one
224 // value and we check that it is fine above.
226 // FIXME: Maybe we should handle things like targets that don't support full
227 // 32-bit immediates?
229 case ISD::ConstantFP: {
230 // Spill FP immediates to the constant pool if the target cannot directly
231 // codegen them. Targets often have some immediate values that can be
232 // efficiently generated into an FP register without a load. We explicitly
233 // leave these constants as ConstantFP nodes for the target to deal with.
235 ConstantFPSDNode *CFP = cast<ConstantFPSDNode>(Node);
237 // Check to see if this FP immediate is already legal.
238 bool isLegal = false;
239 for (TargetLowering::legal_fpimm_iterator I = TLI.legal_fpimm_begin(),
240 E = TLI.legal_fpimm_end(); I != E; ++I)
241 if (CFP->isExactlyValue(*I)) {
247 // Otherwise we need to spill the constant to memory.
248 MachineConstantPool *CP = DAG.getMachineFunction().getConstantPool();
252 // If a FP immediate is precise when represented as a float, we put it
253 // into the constant pool as a float, even if it's is statically typed
255 MVT::ValueType VT = CFP->getValueType(0);
256 bool isDouble = VT == MVT::f64;
257 ConstantFP *LLVMC = ConstantFP::get(isDouble ? Type::DoubleTy :
258 Type::FloatTy, CFP->getValue());
259 if (isDouble && CFP->isExactlyValue((float)CFP->getValue()) &&
260 // Only do this if the target has a native EXTLOAD instruction from
262 TLI.getOperationAction(ISD::EXTLOAD,
263 MVT::f32) == TargetLowering::Legal) {
264 LLVMC = cast<ConstantFP>(ConstantExpr::getCast(LLVMC, Type::FloatTy));
269 SDOperand CPIdx = DAG.getConstantPool(CP->getConstantPoolIndex(LLVMC),
272 Result = DAG.getNode(ISD::EXTLOAD, MVT::f64, DAG.getEntryNode(), CPIdx,
275 Result = DAG.getLoad(VT, DAG.getEntryNode(), CPIdx);
280 case ISD::TokenFactor: {
281 std::vector<SDOperand> Ops;
282 bool Changed = false;
283 for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
284 SDOperand Op = Node->getOperand(i);
285 // Fold single-use TokenFactor nodes into this token factor as we go.
286 if (Op.getOpcode() == ISD::TokenFactor && Op.hasOneUse()) {
288 for (unsigned j = 0, e = Op.getNumOperands(); j != e; ++j)
289 Ops.push_back(LegalizeOp(Op.getOperand(j)));
291 Ops.push_back(LegalizeOp(Op)); // Legalize the operands
292 Changed |= Ops[i] != Op;
296 Result = DAG.getNode(ISD::TokenFactor, MVT::Other, Ops);
300 case ISD::ADJCALLSTACKDOWN:
301 case ISD::ADJCALLSTACKUP:
302 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
303 // There is no need to legalize the size argument (Operand #1)
304 if (Tmp1 != Node->getOperand(0))
305 Result = DAG.getNode(Node->getOpcode(), MVT::Other, Tmp1,
306 Node->getOperand(1));
308 case ISD::DYNAMIC_STACKALLOC:
309 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
310 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the size.
311 Tmp3 = LegalizeOp(Node->getOperand(2)); // Legalize the alignment.
312 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) ||
313 Tmp3 != Node->getOperand(2))
314 Result = DAG.getNode(ISD::DYNAMIC_STACKALLOC, Node->getValueType(0),
317 Result = Op.getValue(0);
319 // Since this op produces two values, make sure to remember that we
320 // legalized both of them.
321 AddLegalizedOperand(SDOperand(Node, 0), Result);
322 AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1));
323 return Result.getValue(Op.ResNo);
326 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
327 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the callee.
329 bool Changed = false;
330 std::vector<SDOperand> Ops;
331 for (unsigned i = 2, e = Node->getNumOperands(); i != e; ++i) {
332 Ops.push_back(LegalizeOp(Node->getOperand(i)));
333 Changed |= Ops.back() != Node->getOperand(i);
336 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) || Changed) {
337 std::vector<MVT::ValueType> RetTyVTs;
338 RetTyVTs.reserve(Node->getNumValues());
339 for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i)
340 RetTyVTs.push_back(Node->getValueType(i));
341 Result = SDOperand(DAG.getCall(RetTyVTs, Tmp1, Tmp2, Ops), 0);
343 Result = Result.getValue(0);
345 // Since calls produce multiple values, make sure to remember that we
346 // legalized all of them.
347 for (unsigned i = 0, e = Node->getNumValues(); i != e; ++i)
348 AddLegalizedOperand(SDOperand(Node, i), Result.getValue(i));
349 return Result.getValue(Op.ResNo);
352 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
353 if (Tmp1 != Node->getOperand(0))
354 Result = DAG.getNode(ISD::BR, MVT::Other, Tmp1, Node->getOperand(1));
358 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
360 switch (getTypeAction(Node->getOperand(1).getValueType())) {
361 case Expand: assert(0 && "It's impossible to expand bools");
363 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the condition.
366 Tmp2 = PromoteOp(Node->getOperand(1)); // Promote the condition.
369 // Basic block destination (Op#2) is always legal.
370 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
371 Result = DAG.getNode(ISD::BRCOND, MVT::Other, Tmp1, Tmp2,
372 Node->getOperand(2));
376 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
377 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer.
378 if (Tmp1 != Node->getOperand(0) ||
379 Tmp2 != Node->getOperand(1))
380 Result = DAG.getLoad(Node->getValueType(0), Tmp1, Tmp2);
382 Result = SDOperand(Node, 0);
384 // Since loads produce two values, make sure to remember that we legalized
386 AddLegalizedOperand(SDOperand(Node, 0), Result);
387 AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1));
388 return Result.getValue(Op.ResNo);
393 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
394 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer.
395 if (Tmp1 != Node->getOperand(0) ||
396 Tmp2 != Node->getOperand(1))
397 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1, Tmp2,
398 cast<MVTSDNode>(Node)->getExtraValueType());
400 Result = SDOperand(Node, 0);
402 // Since loads produce two values, make sure to remember that we legalized
404 AddLegalizedOperand(SDOperand(Node, 0), Result);
405 AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1));
406 return Result.getValue(Op.ResNo);
408 case ISD::EXTRACT_ELEMENT:
409 // Get both the low and high parts.
410 ExpandOp(Node->getOperand(0), Tmp1, Tmp2);
411 if (cast<ConstantSDNode>(Node->getOperand(1))->getValue())
412 Result = Tmp2; // 1 -> Hi
414 Result = Tmp1; // 0 -> Lo
418 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
420 switch (getTypeAction(Node->getOperand(1).getValueType())) {
422 // Legalize the incoming value (must be legal).
423 Tmp2 = LegalizeOp(Node->getOperand(1));
424 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
425 Result = DAG.getCopyToReg(Tmp1, Tmp2, cast<RegSDNode>(Node)->getReg());
428 Tmp2 = PromoteOp(Node->getOperand(1));
429 Result = DAG.getCopyToReg(Tmp1, Tmp2, cast<RegSDNode>(Node)->getReg());
433 ExpandOp(Node->getOperand(1), Lo, Hi);
434 unsigned Reg = cast<RegSDNode>(Node)->getReg();
435 Lo = DAG.getCopyToReg(Tmp1, Lo, Reg);
436 Hi = DAG.getCopyToReg(Tmp1, Hi, Reg+1);
437 // Note that the copytoreg nodes are independent of each other.
438 Result = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo, Hi);
439 assert(isTypeLegal(Result.getValueType()) &&
440 "Cannot expand multiple times yet (i64 -> i16)");
446 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
447 switch (Node->getNumOperands()) {
449 switch (getTypeAction(Node->getOperand(1).getValueType())) {
451 Tmp2 = LegalizeOp(Node->getOperand(1));
452 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
453 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Tmp2);
457 ExpandOp(Node->getOperand(1), Lo, Hi);
458 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Lo, Hi);
462 Tmp2 = PromoteOp(Node->getOperand(1));
463 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1, Tmp2);
468 if (Tmp1 != Node->getOperand(0))
469 Result = DAG.getNode(ISD::RET, MVT::Other, Tmp1);
471 default: { // ret <values>
472 std::vector<SDOperand> NewValues;
473 NewValues.push_back(Tmp1);
474 for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i)
475 switch (getTypeAction(Node->getOperand(i).getValueType())) {
477 NewValues.push_back(LegalizeOp(Node->getOperand(i)));
481 ExpandOp(Node->getOperand(i), Lo, Hi);
482 NewValues.push_back(Lo);
483 NewValues.push_back(Hi);
487 assert(0 && "Can't promote multiple return value yet!");
489 Result = DAG.getNode(ISD::RET, MVT::Other, NewValues);
495 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
496 Tmp2 = LegalizeOp(Node->getOperand(2)); // Legalize the pointer.
498 // Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr'
499 if (ConstantFPSDNode *CFP =dyn_cast<ConstantFPSDNode>(Node->getOperand(1))){
500 if (CFP->getValueType(0) == MVT::f32) {
505 V.F = CFP->getValue();
506 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1,
507 DAG.getConstant(V.I, MVT::i32), Tmp2);
509 assert(CFP->getValueType(0) == MVT::f64 && "Unknown FP type!");
514 V.F = CFP->getValue();
515 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1,
516 DAG.getConstant(V.I, MVT::i64), Tmp2);
522 switch (getTypeAction(Node->getOperand(1).getValueType())) {
524 SDOperand Val = LegalizeOp(Node->getOperand(1));
525 if (Val != Node->getOperand(1) || Tmp1 != Node->getOperand(0) ||
526 Tmp2 != Node->getOperand(2))
527 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Val, Tmp2);
531 // Truncate the value and store the result.
532 Tmp3 = PromoteOp(Node->getOperand(1));
533 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, Tmp1, Tmp3, Tmp2,
534 Node->getOperand(1).getValueType());
539 ExpandOp(Node->getOperand(1), Lo, Hi);
541 if (!TLI.isLittleEndian())
544 Lo = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Lo, Tmp2);
546 unsigned IncrementSize = MVT::getSizeInBits(Hi.getValueType())/8;
547 Tmp2 = DAG.getNode(ISD::ADD, Tmp2.getValueType(), Tmp2,
548 getIntPtrConstant(IncrementSize));
549 assert(isTypeLegal(Tmp2.getValueType()) &&
550 "Pointers must be legal!");
551 Hi = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Hi, Tmp2);
552 Result = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo, Hi);
556 case ISD::TRUNCSTORE:
557 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
558 Tmp3 = LegalizeOp(Node->getOperand(2)); // Legalize the pointer.
560 switch (getTypeAction(Node->getOperand(1).getValueType())) {
562 Tmp2 = LegalizeOp(Node->getOperand(1));
563 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) ||
564 Tmp3 != Node->getOperand(2))
565 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, Tmp1, Tmp2, Tmp3,
566 cast<MVTSDNode>(Node)->getExtraValueType());
570 assert(0 && "Cannot handle illegal TRUNCSTORE yet!");
574 switch (getTypeAction(Node->getOperand(0).getValueType())) {
575 case Expand: assert(0 && "It's impossible to expand bools");
577 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the condition.
580 Tmp1 = PromoteOp(Node->getOperand(0)); // Promote the condition.
583 Tmp2 = LegalizeOp(Node->getOperand(1)); // TrueVal
584 Tmp3 = LegalizeOp(Node->getOperand(2)); // FalseVal
586 switch (TLI.getOperationAction(Node->getOpcode(), Tmp2.getValueType())) {
587 default: assert(0 && "This action is not supported yet!");
588 case TargetLowering::Legal:
589 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) ||
590 Tmp3 != Node->getOperand(2))
591 Result = DAG.getNode(ISD::SELECT, Node->getValueType(0),
594 case TargetLowering::Promote: {
596 TLI.getTypeToPromoteTo(ISD::SELECT, Tmp2.getValueType());
597 unsigned ExtOp, TruncOp;
598 if (MVT::isInteger(Tmp2.getValueType())) {
599 ExtOp = ISD::ZERO_EXTEND;
600 TruncOp = ISD::TRUNCATE;
602 ExtOp = ISD::FP_EXTEND;
603 TruncOp = ISD::FP_ROUND;
605 // Promote each of the values to the new type.
606 Tmp2 = DAG.getNode(ExtOp, NVT, Tmp2);
607 Tmp3 = DAG.getNode(ExtOp, NVT, Tmp3);
608 // Perform the larger operation, then round down.
609 Result = DAG.getNode(ISD::SELECT, NVT, Tmp1, Tmp2,Tmp3);
610 Result = DAG.getNode(TruncOp, Node->getValueType(0), Result);
616 switch (getTypeAction(Node->getOperand(0).getValueType())) {
618 Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS
619 Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS
620 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
621 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
622 Node->getValueType(0), Tmp1, Tmp2);
625 Tmp1 = PromoteOp(Node->getOperand(0)); // LHS
626 Tmp2 = PromoteOp(Node->getOperand(1)); // RHS
628 // If this is an FP compare, the operands have already been extended.
629 if (MVT::isInteger(Node->getOperand(0).getValueType())) {
630 MVT::ValueType VT = Node->getOperand(0).getValueType();
631 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT);
633 // Otherwise, we have to insert explicit sign or zero extends. Note
634 // that we could insert sign extends for ALL conditions, but zero extend
635 // is cheaper on many machines (an AND instead of two shifts), so prefer
637 switch (cast<SetCCSDNode>(Node)->getCondition()) {
638 default: assert(0 && "Unknown integer comparison!");
645 // ALL of these operations will work if we either sign or zero extend
646 // the operands (including the unsigned comparisons!). Zero extend is
647 // usually a simpler/cheaper operation, so prefer it.
648 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT);
649 Tmp2 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp2, VT);
655 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT);
656 Tmp2 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp2, VT);
661 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
662 Node->getValueType(0), Tmp1, Tmp2);
665 SDOperand LHSLo, LHSHi, RHSLo, RHSHi;
666 ExpandOp(Node->getOperand(0), LHSLo, LHSHi);
667 ExpandOp(Node->getOperand(1), RHSLo, RHSHi);
668 switch (cast<SetCCSDNode>(Node)->getCondition()) {
671 Tmp1 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSLo, RHSLo);
672 Tmp2 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSHi, RHSHi);
673 Tmp1 = DAG.getNode(ISD::OR, Tmp1.getValueType(), Tmp1, Tmp2);
674 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
675 Node->getValueType(0), Tmp1,
676 DAG.getConstant(0, Tmp1.getValueType()));
679 // FIXME: This generated code sucks.
681 switch (cast<SetCCSDNode>(Node)->getCondition()) {
682 default: assert(0 && "Unknown integer setcc!");
684 case ISD::SETULT: LowCC = ISD::SETULT; break;
686 case ISD::SETUGT: LowCC = ISD::SETUGT; break;
688 case ISD::SETULE: LowCC = ISD::SETULE; break;
690 case ISD::SETUGE: LowCC = ISD::SETUGE; break;
693 // Tmp1 = lo(op1) < lo(op2) // Always unsigned comparison
694 // Tmp2 = hi(op1) < hi(op2) // Signedness depends on operands
695 // dest = hi(op1) == hi(op2) ? Tmp1 : Tmp2;
697 // NOTE: on targets without efficient SELECT of bools, we can always use
698 // this identity: (B1 ? B2 : B3) --> (B1 & B2)|(!B1&B3)
699 Tmp1 = DAG.getSetCC(LowCC, Node->getValueType(0), LHSLo, RHSLo);
700 Tmp2 = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
701 Node->getValueType(0), LHSHi, RHSHi);
702 Result = DAG.getSetCC(ISD::SETEQ, Node->getValueType(0), LHSHi, RHSHi);
703 Result = DAG.getNode(ISD::SELECT, Tmp1.getValueType(),
713 Tmp1 = LegalizeOp(Node->getOperand(0)); // Chain
714 Tmp2 = LegalizeOp(Node->getOperand(1)); // Pointer
716 if (Node->getOpcode() == ISD::MEMSET) { // memset = ubyte
717 switch (getTypeAction(Node->getOperand(2).getValueType())) {
718 case Expand: assert(0 && "Cannot expand a byte!");
720 Tmp3 = LegalizeOp(Node->getOperand(2));
723 Tmp3 = PromoteOp(Node->getOperand(2));
727 Tmp3 = LegalizeOp(Node->getOperand(2)); // memcpy/move = pointer,
731 switch (getTypeAction(Node->getOperand(3).getValueType())) {
732 case Expand: assert(0 && "Cannot expand this yet!");
734 Tmp4 = LegalizeOp(Node->getOperand(3));
737 Tmp4 = PromoteOp(Node->getOperand(3));
742 switch (getTypeAction(Node->getOperand(4).getValueType())) { // uint
743 case Expand: assert(0 && "Cannot expand this yet!");
745 Tmp5 = LegalizeOp(Node->getOperand(4));
748 Tmp5 = PromoteOp(Node->getOperand(4));
752 switch (TLI.getOperationAction(Node->getOpcode(), MVT::Other)) {
753 default: assert(0 && "This action not implemented for this operation!");
754 case TargetLowering::Legal:
755 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) ||
756 Tmp3 != Node->getOperand(2) || Tmp4 != Node->getOperand(3) ||
757 Tmp5 != Node->getOperand(4)) {
758 std::vector<SDOperand> Ops;
759 Ops.push_back(Tmp1); Ops.push_back(Tmp2); Ops.push_back(Tmp3);
760 Ops.push_back(Tmp4); Ops.push_back(Tmp5);
761 Result = DAG.getNode(Node->getOpcode(), MVT::Other, Ops);
764 case TargetLowering::Expand: {
765 // Otherwise, the target does not support this operation. Lower the
766 // operation to an explicit libcall as appropriate.
767 MVT::ValueType IntPtr = TLI.getPointerTy();
768 const Type *IntPtrTy = TLI.getTargetData().getIntPtrType();
769 std::vector<std::pair<SDOperand, const Type*> > Args;
771 const char *FnName = 0;
772 if (Node->getOpcode() == ISD::MEMSET) {
773 Args.push_back(std::make_pair(Tmp2, IntPtrTy));
774 // Extend the ubyte argument to be an int value for the call.
775 Tmp3 = DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Tmp3);
776 Args.push_back(std::make_pair(Tmp3, Type::IntTy));
777 Args.push_back(std::make_pair(Tmp4, IntPtrTy));
780 } else if (Node->getOpcode() == ISD::MEMCPY ||
781 Node->getOpcode() == ISD::MEMMOVE) {
782 Args.push_back(std::make_pair(Tmp2, IntPtrTy));
783 Args.push_back(std::make_pair(Tmp3, IntPtrTy));
784 Args.push_back(std::make_pair(Tmp4, IntPtrTy));
785 FnName = Node->getOpcode() == ISD::MEMMOVE ? "memmove" : "memcpy";
787 assert(0 && "Unknown op!");
789 std::pair<SDOperand,SDOperand> CallResult =
790 TLI.LowerCallTo(Tmp1, Type::VoidTy,
791 DAG.getExternalSymbol(FnName, IntPtr), Args, DAG);
792 Result = LegalizeOp(CallResult.second);
795 case TargetLowering::Custom:
796 std::vector<SDOperand> Ops;
797 Ops.push_back(Tmp1); Ops.push_back(Tmp2); Ops.push_back(Tmp3);
798 Ops.push_back(Tmp4); Ops.push_back(Tmp5);
799 Result = DAG.getNode(Node->getOpcode(), MVT::Other, Ops);
800 Result = TLI.LowerOperation(Result);
801 Result = LegalizeOp(Result);
807 case ISD::SUB_PARTS: {
808 std::vector<SDOperand> Ops;
809 bool Changed = false;
810 for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
811 Ops.push_back(LegalizeOp(Node->getOperand(i)));
812 Changed |= Ops.back() != Node->getOperand(i);
815 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Ops);
831 Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS
832 Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS
833 if (Tmp1 != Node->getOperand(0) ||
834 Tmp2 != Node->getOperand(1))
835 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1,Tmp2);
837 case ISD::ZERO_EXTEND:
838 case ISD::SIGN_EXTEND:
842 case ISD::FP_TO_SINT:
843 case ISD::FP_TO_UINT:
844 case ISD::SINT_TO_FP:
845 case ISD::UINT_TO_FP:
846 switch (getTypeAction(Node->getOperand(0).getValueType())) {
848 Tmp1 = LegalizeOp(Node->getOperand(0));
849 if (Tmp1 != Node->getOperand(0))
850 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1);
853 if (Node->getOpcode() == ISD::SINT_TO_FP ||
854 Node->getOpcode() == ISD::UINT_TO_FP) {
855 Result = ExpandIntToFP(Node->getOpcode() == ISD::SINT_TO_FP,
856 Node->getValueType(0), Node->getOperand(0));
857 Result = LegalizeOp(Result);
860 // In the expand case, we must be dealing with a truncate, because
861 // otherwise the result would be larger than the source.
862 assert(Node->getOpcode() == ISD::TRUNCATE &&
863 "Shouldn't need to expand other operators here!");
864 ExpandOp(Node->getOperand(0), Tmp1, Tmp2);
866 // Since the result is legal, we should just be able to truncate the low
867 // part of the source.
868 Result = DAG.getNode(ISD::TRUNCATE, Node->getValueType(0), Tmp1);
872 switch (Node->getOpcode()) {
873 case ISD::ZERO_EXTEND:
874 Result = PromoteOp(Node->getOperand(0));
875 // NOTE: Any extend would work here...
876 Result = DAG.getNode(ISD::ZERO_EXTEND, Op.getValueType(), Result);
877 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, Op.getValueType(),
878 Result, Node->getOperand(0).getValueType());
880 case ISD::SIGN_EXTEND:
881 Result = PromoteOp(Node->getOperand(0));
882 // NOTE: Any extend would work here...
883 Result = DAG.getNode(ISD::ZERO_EXTEND, Op.getValueType(), Result);
884 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(),
885 Result, Node->getOperand(0).getValueType());
888 Result = PromoteOp(Node->getOperand(0));
889 Result = DAG.getNode(ISD::TRUNCATE, Op.getValueType(), Result);
892 Result = PromoteOp(Node->getOperand(0));
893 if (Result.getValueType() != Op.getValueType())
894 // Dynamically dead while we have only 2 FP types.
895 Result = DAG.getNode(ISD::FP_EXTEND, Op.getValueType(), Result);
898 case ISD::FP_TO_SINT:
899 case ISD::FP_TO_UINT:
900 Result = PromoteOp(Node->getOperand(0));
901 Result = DAG.getNode(Node->getOpcode(), Op.getValueType(), Result);
903 case ISD::SINT_TO_FP:
904 Result = PromoteOp(Node->getOperand(0));
905 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(),
906 Result, Node->getOperand(0).getValueType());
907 Result = DAG.getNode(ISD::SINT_TO_FP, Op.getValueType(), Result);
909 case ISD::UINT_TO_FP:
910 Result = PromoteOp(Node->getOperand(0));
911 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, Result.getValueType(),
912 Result, Node->getOperand(0).getValueType());
913 Result = DAG.getNode(ISD::UINT_TO_FP, Op.getValueType(), Result);
918 case ISD::FP_ROUND_INREG:
919 case ISD::SIGN_EXTEND_INREG:
920 case ISD::ZERO_EXTEND_INREG: {
921 Tmp1 = LegalizeOp(Node->getOperand(0));
922 MVT::ValueType ExtraVT = cast<MVTSDNode>(Node)->getExtraValueType();
924 // If this operation is not supported, convert it to a shl/shr or load/store
926 switch (TLI.getOperationAction(Node->getOpcode(), ExtraVT)) {
927 default: assert(0 && "This action not supported for this op yet!");
928 case TargetLowering::Legal:
929 if (Tmp1 != Node->getOperand(0))
930 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1,
933 case TargetLowering::Expand:
934 // If this is an integer extend and shifts are supported, do that.
935 if (Node->getOpcode() == ISD::ZERO_EXTEND_INREG) {
936 // NOTE: we could fall back on load/store here too for targets without
937 // AND. However, it is doubtful that any exist.
938 // AND out the appropriate bits.
940 DAG.getConstant((1ULL << MVT::getSizeInBits(ExtraVT))-1,
941 Node->getValueType(0));
942 Result = DAG.getNode(ISD::AND, Node->getValueType(0),
943 Node->getOperand(0), Mask);
944 } else if (Node->getOpcode() == ISD::SIGN_EXTEND_INREG) {
945 // NOTE: we could fall back on load/store here too for targets without
946 // SAR. However, it is doubtful that any exist.
947 unsigned BitsDiff = MVT::getSizeInBits(Node->getValueType(0)) -
948 MVT::getSizeInBits(ExtraVT);
949 SDOperand ShiftCst = DAG.getConstant(BitsDiff, TLI.getShiftAmountTy());
950 Result = DAG.getNode(ISD::SHL, Node->getValueType(0),
951 Node->getOperand(0), ShiftCst);
952 Result = DAG.getNode(ISD::SRA, Node->getValueType(0),
954 } else if (Node->getOpcode() == ISD::FP_ROUND_INREG) {
955 // The only way we can lower this is to turn it into a STORETRUNC,
956 // EXTLOAD pair, targetting a temporary location (a stack slot).
958 // NOTE: there is a choice here between constantly creating new stack
959 // slots and always reusing the same one. We currently always create
960 // new ones, as reuse may inhibit scheduling.
961 const Type *Ty = MVT::getTypeForValueType(ExtraVT);
962 unsigned TySize = (unsigned)TLI.getTargetData().getTypeSize(Ty);
963 unsigned Align = TLI.getTargetData().getTypeAlignment(Ty);
964 MachineFunction &MF = DAG.getMachineFunction();
966 MF.getFrameInfo()->CreateStackObject((unsigned)TySize, Align);
967 SDOperand StackSlot = DAG.getFrameIndex(SSFI, TLI.getPointerTy());
968 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, DAG.getEntryNode(),
969 Node->getOperand(0), StackSlot, ExtraVT);
970 Result = DAG.getNode(ISD::EXTLOAD, Node->getValueType(0),
971 Result, StackSlot, ExtraVT);
973 assert(0 && "Unknown op");
975 Result = LegalizeOp(Result);
982 if (!Op.Val->hasOneUse())
983 AddLegalizedOperand(Op, Result);
988 /// PromoteOp - Given an operation that produces a value in an invalid type,
989 /// promote it to compute the value into a larger type. The produced value will
990 /// have the correct bits for the low portion of the register, but no guarantee
991 /// is made about the top bits: it may be zero, sign-extended, or garbage.
992 SDOperand SelectionDAGLegalize::PromoteOp(SDOperand Op) {
993 MVT::ValueType VT = Op.getValueType();
994 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT);
995 assert(getTypeAction(VT) == Promote &&
996 "Caller should expand or legalize operands that are not promotable!");
997 assert(NVT > VT && MVT::isInteger(NVT) == MVT::isInteger(VT) &&
998 "Cannot promote to smaller type!");
1000 std::map<SDOperand, SDOperand>::iterator I = PromotedNodes.find(Op);
1001 if (I != PromotedNodes.end()) return I->second;
1003 SDOperand Tmp1, Tmp2, Tmp3;
1006 SDNode *Node = Op.Val;
1008 // Promotion needs an optimization step to clean up after it, and is not
1009 // careful to avoid operations the target does not support. Make sure that
1010 // all generated operations are legalized in the next iteration.
1011 NeedsAnotherIteration = true;
1013 switch (Node->getOpcode()) {
1015 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n";
1016 assert(0 && "Do not know how to promote this operator!");
1019 Result = DAG.getNode(ISD::ZERO_EXTEND, NVT, Op);
1020 assert(isa<ConstantSDNode>(Result) && "Didn't constant fold zext?");
1022 case ISD::ConstantFP:
1023 Result = DAG.getNode(ISD::FP_EXTEND, NVT, Op);
1024 assert(isa<ConstantFPSDNode>(Result) && "Didn't constant fold fp_extend?");
1026 case ISD::CopyFromReg:
1027 Result = DAG.getCopyFromReg(cast<RegSDNode>(Node)->getReg(), NVT,
1028 Node->getOperand(0));
1029 // Remember that we legalized the chain.
1030 AddLegalizedOperand(Op.getValue(1), Result.getValue(1));
1034 assert(getTypeAction(TLI.getSetCCResultTy()) == Legal &&
1035 "SetCC type is not legal??");
1036 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
1037 TLI.getSetCCResultTy(), Node->getOperand(0),
1038 Node->getOperand(1));
1039 Result = LegalizeOp(Result);
1043 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1045 Result = LegalizeOp(Node->getOperand(0));
1046 assert(Result.getValueType() >= NVT &&
1047 "This truncation doesn't make sense!");
1048 if (Result.getValueType() > NVT) // Truncate to NVT instead of VT
1049 Result = DAG.getNode(ISD::TRUNCATE, NVT, Result);
1052 // The truncation is not required, because we don't guarantee anything
1053 // about high bits anyway.
1054 Result = PromoteOp(Node->getOperand(0));
1057 assert(0 && "Cannot handle expand yet");
1060 case ISD::SIGN_EXTEND:
1061 case ISD::ZERO_EXTEND:
1062 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1063 case Expand: assert(0 && "BUG: Smaller reg should have been promoted!");
1065 // Input is legal? Just do extend all the way to the larger type.
1066 Result = LegalizeOp(Node->getOperand(0));
1067 Result = DAG.getNode(Node->getOpcode(), NVT, Result);
1070 // Promote the reg if it's smaller.
1071 Result = PromoteOp(Node->getOperand(0));
1072 // The high bits are not guaranteed to be anything. Insert an extend.
1073 if (Node->getOpcode() == ISD::SIGN_EXTEND)
1074 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Result,
1075 Node->getOperand(0).getValueType());
1077 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Result,
1078 Node->getOperand(0).getValueType());
1083 case ISD::FP_EXTEND:
1084 assert(0 && "Case not implemented. Dynamically dead with 2 FP types!");
1086 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1087 case Expand: assert(0 && "BUG: Cannot expand FP regs!");
1088 case Promote: assert(0 && "Unreachable with 2 FP types!");
1090 // Input is legal? Do an FP_ROUND_INREG.
1091 Result = LegalizeOp(Node->getOperand(0));
1092 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT);
1097 case ISD::SINT_TO_FP:
1098 case ISD::UINT_TO_FP:
1099 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1101 Result = LegalizeOp(Node->getOperand(0));
1102 // No extra round required here.
1103 Result = DAG.getNode(Node->getOpcode(), NVT, Result);
1107 Result = PromoteOp(Node->getOperand(0));
1108 if (Node->getOpcode() == ISD::SINT_TO_FP)
1109 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(),
1110 Result, Node->getOperand(0).getValueType());
1112 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, Result.getValueType(),
1113 Result, Node->getOperand(0).getValueType());
1114 // No extra round required here.
1115 Result = DAG.getNode(Node->getOpcode(), NVT, Result);
1118 Result = ExpandIntToFP(Node->getOpcode() == ISD::SINT_TO_FP, NVT,
1119 Node->getOperand(0));
1120 Result = LegalizeOp(Result);
1122 // Round if we cannot tolerate excess precision.
1123 if (NoExcessFPPrecision)
1124 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT);
1129 case ISD::FP_TO_SINT:
1130 case ISD::FP_TO_UINT:
1131 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1133 Tmp1 = LegalizeOp(Node->getOperand(0));
1136 // The input result is prerounded, so we don't have to do anything
1138 Tmp1 = PromoteOp(Node->getOperand(0));
1141 assert(0 && "not implemented");
1143 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1);
1152 // The input may have strange things in the top bits of the registers, but
1153 // these operations don't care. They may have wierd bits going out, but
1154 // that too is okay if they are integer operations.
1155 Tmp1 = PromoteOp(Node->getOperand(0));
1156 Tmp2 = PromoteOp(Node->getOperand(1));
1157 assert(Tmp1.getValueType() == NVT && Tmp2.getValueType() == NVT);
1158 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2);
1160 // However, if this is a floating point operation, they will give excess
1161 // precision that we may not be able to tolerate. If we DO allow excess
1162 // precision, just leave it, otherwise excise it.
1163 // FIXME: Why would we need to round FP ops more than integer ones?
1164 // Is Round(Add(Add(A,B),C)) != Round(Add(Round(Add(A,B)), C))
1165 if (MVT::isFloatingPoint(NVT) && NoExcessFPPrecision)
1166 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT);
1171 // These operators require that their input be sign extended.
1172 Tmp1 = PromoteOp(Node->getOperand(0));
1173 Tmp2 = PromoteOp(Node->getOperand(1));
1174 if (MVT::isInteger(NVT)) {
1175 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT);
1176 Tmp2 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp2, VT);
1178 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2);
1180 // Perform FP_ROUND: this is probably overly pessimistic.
1181 if (MVT::isFloatingPoint(NVT) && NoExcessFPPrecision)
1182 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT);
1187 // These operators require that their input be zero extended.
1188 Tmp1 = PromoteOp(Node->getOperand(0));
1189 Tmp2 = PromoteOp(Node->getOperand(1));
1190 assert(MVT::isInteger(NVT) && "Operators don't apply to FP!");
1191 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT);
1192 Tmp2 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp2, VT);
1193 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2);
1197 Tmp1 = PromoteOp(Node->getOperand(0));
1198 Tmp2 = LegalizeOp(Node->getOperand(1));
1199 Result = DAG.getNode(ISD::SHL, NVT, Tmp1, Tmp2);
1202 // The input value must be properly sign extended.
1203 Tmp1 = PromoteOp(Node->getOperand(0));
1204 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT);
1205 Tmp2 = LegalizeOp(Node->getOperand(1));
1206 Result = DAG.getNode(ISD::SRA, NVT, Tmp1, Tmp2);
1209 // The input value must be properly zero extended.
1210 Tmp1 = PromoteOp(Node->getOperand(0));
1211 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT);
1212 Tmp2 = LegalizeOp(Node->getOperand(1));
1213 Result = DAG.getNode(ISD::SRL, NVT, Tmp1, Tmp2);
1216 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
1217 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer.
1218 Result = DAG.getNode(ISD::EXTLOAD, NVT, Tmp1, Tmp2, VT);
1220 // Remember that we legalized the chain.
1221 AddLegalizedOperand(Op.getValue(1), Result.getValue(1));
1224 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1225 case Expand: assert(0 && "It's impossible to expand bools");
1227 Tmp1 = LegalizeOp(Node->getOperand(0));// Legalize the condition.
1230 Tmp1 = PromoteOp(Node->getOperand(0)); // Promote the condition.
1233 Tmp2 = PromoteOp(Node->getOperand(1)); // Legalize the op0
1234 Tmp3 = PromoteOp(Node->getOperand(2)); // Legalize the op1
1235 Result = DAG.getNode(ISD::SELECT, NVT, Tmp1, Tmp2, Tmp3);
1238 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
1239 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the callee.
1241 std::vector<SDOperand> Ops;
1242 for (unsigned i = 2, e = Node->getNumOperands(); i != e; ++i)
1243 Ops.push_back(LegalizeOp(Node->getOperand(i)));
1245 assert(Node->getNumValues() == 2 && Op.ResNo == 0 &&
1246 "Can only promote single result calls");
1247 std::vector<MVT::ValueType> RetTyVTs;
1248 RetTyVTs.reserve(2);
1249 RetTyVTs.push_back(NVT);
1250 RetTyVTs.push_back(MVT::Other);
1251 SDNode *NC = DAG.getCall(RetTyVTs, Tmp1, Tmp2, Ops);
1252 Result = SDOperand(NC, 0);
1254 // Insert the new chain mapping.
1255 AddLegalizedOperand(Op.getValue(1), Result.getValue(1));
1260 assert(Result.Val && "Didn't set a result!");
1261 AddPromotedOperand(Op, Result);
1265 /// ExpandAddSub - Find a clever way to expand this add operation into
1267 void SelectionDAGLegalize::ExpandAddSub(bool isAdd, SDOperand LHS,SDOperand RHS,
1268 SDOperand &Lo, SDOperand &Hi) {
1269 // Expand the subcomponents.
1270 SDOperand LHSL, LHSH, RHSL, RHSH;
1271 ExpandOp(LHS, LHSL, LHSH);
1272 ExpandOp(RHS, RHSL, RHSH);
1274 // Convert this add to the appropriate ADDC pair. The low part has no carry
1276 unsigned Opc = isAdd ? ISD::ADD_PARTS : ISD::SUB_PARTS;
1277 std::vector<SDOperand> Ops;
1278 Ops.push_back(LHSL);
1279 Ops.push_back(LHSH);
1280 Ops.push_back(RHSL);
1281 Ops.push_back(RHSH);
1282 Lo = DAG.getNode(Opc, LHSL.getValueType(), Ops);
1283 Hi = Lo.getValue(1);
1286 /// ExpandShift - Try to find a clever way to expand this shift operation out to
1287 /// smaller elements. If we can't find a way that is more efficient than a
1288 /// libcall on this target, return false. Otherwise, return true with the
1289 /// low-parts expanded into Lo and Hi.
1290 bool SelectionDAGLegalize::ExpandShift(unsigned Opc, SDOperand Op,SDOperand Amt,
1291 SDOperand &Lo, SDOperand &Hi) {
1292 assert((Opc == ISD::SHL || Opc == ISD::SRA || Opc == ISD::SRL) &&
1293 "This is not a shift!");
1294 MVT::ValueType NVT = TLI.getTypeToTransformTo(Op.getValueType());
1296 // If we have an efficient select operation (or if the selects will all fold
1297 // away), lower to some complex code, otherwise just emit the libcall.
1298 if (TLI.getOperationAction(ISD::SELECT, NVT) != TargetLowering::Legal &&
1299 !isa<ConstantSDNode>(Amt))
1303 ExpandOp(Op, InL, InH);
1304 SDOperand ShAmt = LegalizeOp(Amt);
1305 MVT::ValueType ShTy = ShAmt.getValueType();
1307 unsigned NVTBits = MVT::getSizeInBits(NVT);
1308 SDOperand NAmt = DAG.getNode(ISD::SUB, ShTy, // NAmt = 32-ShAmt
1309 DAG.getConstant(NVTBits, ShTy), ShAmt);
1311 // Compare the unmasked shift amount against 32.
1312 SDOperand Cond = DAG.getSetCC(ISD::SETGE, TLI.getSetCCResultTy(), ShAmt,
1313 DAG.getConstant(NVTBits, ShTy));
1315 if (TLI.getShiftAmountFlavor() != TargetLowering::Mask) {
1316 ShAmt = DAG.getNode(ISD::AND, ShTy, ShAmt, // ShAmt &= 31
1317 DAG.getConstant(NVTBits-1, ShTy));
1318 NAmt = DAG.getNode(ISD::AND, ShTy, NAmt, // NAmt &= 31
1319 DAG.getConstant(NVTBits-1, ShTy));
1322 if (Opc == ISD::SHL) {
1323 SDOperand T1 = DAG.getNode(ISD::OR, NVT,// T1 = (Hi << Amt) | (Lo >> NAmt)
1324 DAG.getNode(ISD::SHL, NVT, InH, ShAmt),
1325 DAG.getNode(ISD::SRL, NVT, InL, NAmt));
1326 SDOperand T2 = DAG.getNode(ISD::SHL, NVT, InL, ShAmt); // T2 = Lo << Amt&31
1328 Hi = DAG.getNode(ISD::SELECT, NVT, Cond, T2, T1);
1329 Lo = DAG.getNode(ISD::SELECT, NVT, Cond, DAG.getConstant(0, NVT), T2);
1331 SDOperand HiLoPart = DAG.getNode(ISD::SELECT, NVT,
1332 DAG.getSetCC(ISD::SETEQ,
1333 TLI.getSetCCResultTy(), NAmt,
1334 DAG.getConstant(32, ShTy)),
1335 DAG.getConstant(0, NVT),
1336 DAG.getNode(ISD::SHL, NVT, InH, NAmt));
1337 SDOperand T1 = DAG.getNode(ISD::OR, NVT,// T1 = (Hi << NAmt) | (Lo >> Amt)
1339 DAG.getNode(ISD::SRL, NVT, InL, ShAmt));
1340 SDOperand T2 = DAG.getNode(Opc, NVT, InH, ShAmt); // T2 = InH >> ShAmt&31
1343 if (Opc == ISD::SRA)
1344 HiPart = DAG.getNode(ISD::SRA, NVT, InH,
1345 DAG.getConstant(NVTBits-1, ShTy));
1347 HiPart = DAG.getConstant(0, NVT);
1348 Lo = DAG.getNode(ISD::SELECT, NVT, Cond, T2, T1);
1349 Hi = DAG.getNode(ISD::SELECT, NVT, Cond, HiPart, T2);
1354 /// FindLatestAdjCallStackDown - Scan up the dag to find the latest (highest
1355 /// NodeDepth) node that is an AdjCallStackDown operation and occurs later than
1357 static void FindLatestAdjCallStackDown(SDNode *Node, SDNode *&Found) {
1358 if (Node->getNodeDepth() <= Found->getNodeDepth()) return;
1360 // If we found an ADJCALLSTACKDOWN, we already know this node occurs later
1361 // than the Found node. Just remember this node and return.
1362 if (Node->getOpcode() == ISD::ADJCALLSTACKDOWN) {
1367 // Otherwise, scan the operands of Node to see if any of them is a call.
1368 assert(Node->getNumOperands() != 0 &&
1369 "All leaves should have depth equal to the entry node!");
1370 for (unsigned i = 0, e = Node->getNumOperands()-1; i != e; ++i)
1371 FindLatestAdjCallStackDown(Node->getOperand(i).Val, Found);
1373 // Tail recurse for the last iteration.
1374 FindLatestAdjCallStackDown(Node->getOperand(Node->getNumOperands()-1).Val,
1379 /// FindEarliestAdjCallStackUp - Scan down the dag to find the earliest (lowest
1380 /// NodeDepth) node that is an AdjCallStackUp operation and occurs more recent
1382 static void FindEarliestAdjCallStackUp(SDNode *Node, SDNode *&Found) {
1383 if (Found && Node->getNodeDepth() >= Found->getNodeDepth()) return;
1385 // If we found an ADJCALLSTACKUP, we already know this node occurs earlier
1386 // than the Found node. Just remember this node and return.
1387 if (Node->getOpcode() == ISD::ADJCALLSTACKUP) {
1392 // Otherwise, scan the operands of Node to see if any of them is a call.
1393 SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
1394 if (UI == E) return;
1395 for (--E; UI != E; ++UI)
1396 FindEarliestAdjCallStackUp(*UI, Found);
1398 // Tail recurse for the last iteration.
1399 FindEarliestAdjCallStackUp(*UI, Found);
1402 /// FindAdjCallStackUp - Given a chained node that is part of a call sequence,
1403 /// find the ADJCALLSTACKUP node that terminates the call sequence.
1404 static SDNode *FindAdjCallStackUp(SDNode *Node) {
1405 if (Node->getOpcode() == ISD::ADJCALLSTACKUP)
1407 assert(!Node->use_empty() && "Could not find ADJCALLSTACKUP!");
1409 if (Node->hasOneUse()) // Simple case, only has one user to check.
1410 return FindAdjCallStackUp(*Node->use_begin());
1412 SDOperand TheChain(Node, Node->getNumValues()-1);
1413 assert(TheChain.getValueType() == MVT::Other && "Is not a token chain!");
1415 for (SDNode::use_iterator UI = Node->use_begin(),
1416 E = Node->use_end(); ; ++UI) {
1417 assert(UI != E && "Didn't find a user of the tokchain, no ADJCALLSTACKUP!");
1419 // Make sure to only follow users of our token chain.
1421 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i)
1422 if (User->getOperand(i) == TheChain)
1423 return FindAdjCallStackUp(User);
1425 assert(0 && "Unreachable");
1429 /// FindInputOutputChains - If we are replacing an operation with a call we need
1430 /// to find the call that occurs before and the call that occurs after it to
1431 /// properly serialize the calls in the block.
1432 static SDOperand FindInputOutputChains(SDNode *OpNode, SDNode *&OutChain,
1434 SDNode *LatestAdjCallStackDown = Entry.Val;
1435 FindLatestAdjCallStackDown(OpNode, LatestAdjCallStackDown);
1436 //std::cerr << "Found node: "; LatestAdjCallStackDown->dump(); std::cerr <<"\n";
1438 SDNode *LatestAdjCallStackUp = FindAdjCallStackUp(LatestAdjCallStackDown);
1441 SDNode *EarliestAdjCallStackUp = 0;
1442 FindEarliestAdjCallStackUp(OpNode, EarliestAdjCallStackUp);
1444 if (EarliestAdjCallStackUp) {
1445 //std::cerr << "Found node: ";
1446 //EarliestAdjCallStackUp->dump(); std::cerr <<"\n";
1449 return SDOperand(LatestAdjCallStackUp, 0);
1454 // ExpandLibCall - Expand a node into a call to a libcall. If the result value
1455 // does not fit into a register, return the lo part and set the hi part to the
1456 // by-reg argument. If it does fit into a single register, return the result
1457 // and leave the Hi part unset.
1458 SDOperand SelectionDAGLegalize::ExpandLibCall(const char *Name, SDNode *Node,
1461 SDOperand InChain = FindInputOutputChains(Node, OutChain,
1462 DAG.getEntryNode());
1463 // TODO. Link in chains.
1465 TargetLowering::ArgListTy Args;
1466 for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
1467 MVT::ValueType ArgVT = Node->getOperand(i).getValueType();
1468 const Type *ArgTy = MVT::getTypeForValueType(ArgVT);
1469 Args.push_back(std::make_pair(Node->getOperand(i), ArgTy));
1471 SDOperand Callee = DAG.getExternalSymbol(Name, TLI.getPointerTy());
1473 // We don't care about token chains for libcalls. We just use the entry
1474 // node as our input and ignore the output chain. This allows us to place
1475 // calls wherever we need them to satisfy data dependences.
1476 const Type *RetTy = MVT::getTypeForValueType(Node->getValueType(0));
1477 SDOperand Result = TLI.LowerCallTo(InChain, RetTy, Callee,
1479 switch (getTypeAction(Result.getValueType())) {
1480 default: assert(0 && "Unknown thing");
1484 assert(0 && "Cannot promote this yet!");
1487 ExpandOp(Result, Lo, Hi);
1493 /// ExpandIntToFP - Expand a [US]INT_TO_FP operation, assuming that the
1494 /// destination type is legal.
1495 SDOperand SelectionDAGLegalize::
1496 ExpandIntToFP(bool isSigned, MVT::ValueType DestTy, SDOperand Source) {
1497 assert(getTypeAction(DestTy) == Legal && "Destination type is not legal!");
1498 assert(getTypeAction(Source.getValueType()) == Expand &&
1499 "This is not an expansion!");
1500 assert(Source.getValueType() == MVT::i64 && "Only handle expand from i64!");
1503 SDOperand InChain = FindInputOutputChains(Source.Val, OutChain,
1504 DAG.getEntryNode());
1506 const char *FnName = 0;
1508 if (DestTy == MVT::f32)
1509 FnName = "__floatdisf";
1511 assert(DestTy == MVT::f64 && "Unknown fp value type!");
1512 FnName = "__floatdidf";
1515 // If this is unsigned, and not supported, first perform the conversion to
1516 // signed, then adjust the result if the sign bit is set.
1517 SDOperand SignedConv = ExpandIntToFP(false, DestTy, Source);
1519 assert(0 && "Unsigned casts not supported yet!");
1521 SDOperand Callee = DAG.getExternalSymbol(FnName, TLI.getPointerTy());
1523 TargetLowering::ArgListTy Args;
1524 const Type *ArgTy = MVT::getTypeForValueType(Source.getValueType());
1525 Args.push_back(std::make_pair(Source, ArgTy));
1527 // We don't care about token chains for libcalls. We just use the entry
1528 // node as our input and ignore the output chain. This allows us to place
1529 // calls wherever we need them to satisfy data dependences.
1530 const Type *RetTy = MVT::getTypeForValueType(DestTy);
1531 return TLI.LowerCallTo(InChain, RetTy, Callee, Args, DAG).first;
1537 /// ExpandOp - Expand the specified SDOperand into its two component pieces
1538 /// Lo&Hi. Note that the Op MUST be an expanded type. As a result of this, the
1539 /// LegalizeNodes map is filled in for any results that are not expanded, the
1540 /// ExpandedNodes map is filled in for any results that are expanded, and the
1541 /// Lo/Hi values are returned.
1542 void SelectionDAGLegalize::ExpandOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi){
1543 MVT::ValueType VT = Op.getValueType();
1544 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT);
1545 SDNode *Node = Op.Val;
1546 assert(getTypeAction(VT) == Expand && "Not an expanded type!");
1547 assert(MVT::isInteger(VT) && "Cannot expand FP values!");
1548 assert(MVT::isInteger(NVT) && NVT < VT &&
1549 "Cannot expand to FP value or to larger int value!");
1551 // If there is more than one use of this, see if we already expanded it.
1552 // There is no use remembering values that only have a single use, as the map
1553 // entries will never be reused.
1554 if (!Node->hasOneUse()) {
1555 std::map<SDOperand, std::pair<SDOperand, SDOperand> >::iterator I
1556 = ExpandedNodes.find(Op);
1557 if (I != ExpandedNodes.end()) {
1558 Lo = I->second.first;
1559 Hi = I->second.second;
1564 // Expanding to multiple registers needs to perform an optimization step, and
1565 // is not careful to avoid operations the target does not support. Make sure
1566 // that all generated operations are legalized in the next iteration.
1567 NeedsAnotherIteration = true;
1569 switch (Node->getOpcode()) {
1571 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n";
1572 assert(0 && "Do not know how to expand this operator!");
1574 case ISD::Constant: {
1575 uint64_t Cst = cast<ConstantSDNode>(Node)->getValue();
1576 Lo = DAG.getConstant(Cst, NVT);
1577 Hi = DAG.getConstant(Cst >> MVT::getSizeInBits(NVT), NVT);
1581 case ISD::CopyFromReg: {
1582 unsigned Reg = cast<RegSDNode>(Node)->getReg();
1583 // Aggregate register values are always in consequtive pairs.
1584 Lo = DAG.getCopyFromReg(Reg, NVT, Node->getOperand(0));
1585 Hi = DAG.getCopyFromReg(Reg+1, NVT, Lo.getValue(1));
1587 // Remember that we legalized the chain.
1588 AddLegalizedOperand(Op.getValue(1), Hi.getValue(1));
1590 assert(isTypeLegal(NVT) && "Cannot expand this multiple times yet!");
1595 SDOperand Ch = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
1596 SDOperand Ptr = LegalizeOp(Node->getOperand(1)); // Legalize the pointer.
1597 Lo = DAG.getLoad(NVT, Ch, Ptr);
1599 // Increment the pointer to the other half.
1600 unsigned IncrementSize = MVT::getSizeInBits(Lo.getValueType())/8;
1601 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
1602 getIntPtrConstant(IncrementSize));
1603 Hi = DAG.getLoad(NVT, Ch, Ptr);
1605 // Build a factor node to remember that this load is independent of the
1607 SDOperand TF = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo.getValue(1),
1610 // Remember that we legalized the chain.
1611 AddLegalizedOperand(Op.getValue(1), TF);
1612 if (!TLI.isLittleEndian())
1617 SDOperand Chain = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
1618 SDOperand Callee = LegalizeOp(Node->getOperand(1)); // Legalize the callee.
1620 bool Changed = false;
1621 std::vector<SDOperand> Ops;
1622 for (unsigned i = 2, e = Node->getNumOperands(); i != e; ++i) {
1623 Ops.push_back(LegalizeOp(Node->getOperand(i)));
1624 Changed |= Ops.back() != Node->getOperand(i);
1627 assert(Node->getNumValues() == 2 && Op.ResNo == 0 &&
1628 "Can only expand a call once so far, not i64 -> i16!");
1630 std::vector<MVT::ValueType> RetTyVTs;
1631 RetTyVTs.reserve(3);
1632 RetTyVTs.push_back(NVT);
1633 RetTyVTs.push_back(NVT);
1634 RetTyVTs.push_back(MVT::Other);
1635 SDNode *NC = DAG.getCall(RetTyVTs, Chain, Callee, Ops);
1636 Lo = SDOperand(NC, 0);
1637 Hi = SDOperand(NC, 1);
1639 // Insert the new chain mapping.
1640 AddLegalizedOperand(Op.getValue(1), Hi.getValue(2));
1645 case ISD::XOR: { // Simple logical operators -> two trivial pieces.
1646 SDOperand LL, LH, RL, RH;
1647 ExpandOp(Node->getOperand(0), LL, LH);
1648 ExpandOp(Node->getOperand(1), RL, RH);
1649 Lo = DAG.getNode(Node->getOpcode(), NVT, LL, RL);
1650 Hi = DAG.getNode(Node->getOpcode(), NVT, LH, RH);
1654 SDOperand C, LL, LH, RL, RH;
1656 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1657 case Expand: assert(0 && "It's impossible to expand bools");
1659 C = LegalizeOp(Node->getOperand(0)); // Legalize the condition.
1662 C = PromoteOp(Node->getOperand(0)); // Promote the condition.
1665 ExpandOp(Node->getOperand(1), LL, LH);
1666 ExpandOp(Node->getOperand(2), RL, RH);
1667 Lo = DAG.getNode(ISD::SELECT, NVT, C, LL, RL);
1668 Hi = DAG.getNode(ISD::SELECT, NVT, C, LH, RH);
1671 case ISD::SIGN_EXTEND: {
1672 // The low part is just a sign extension of the input (which degenerates to
1674 Lo = DAG.getNode(ISD::SIGN_EXTEND, NVT, LegalizeOp(Node->getOperand(0)));
1676 // The high part is obtained by SRA'ing all but one of the bits of the lo
1678 unsigned LoSize = MVT::getSizeInBits(Lo.getValueType());
1679 Hi = DAG.getNode(ISD::SRA, NVT, Lo, DAG.getConstant(LoSize-1,
1680 TLI.getShiftAmountTy()));
1683 case ISD::ZERO_EXTEND:
1684 // The low part is just a zero extension of the input (which degenerates to
1686 Lo = DAG.getNode(ISD::ZERO_EXTEND, NVT, LegalizeOp(Node->getOperand(0)));
1688 // The high part is just a zero.
1689 Hi = DAG.getConstant(0, NVT);
1692 // These operators cannot be expanded directly, emit them as calls to
1693 // library functions.
1694 case ISD::FP_TO_SINT:
1695 if (Node->getOperand(0).getValueType() == MVT::f32)
1696 Lo = ExpandLibCall("__fixsfdi", Node, Hi);
1698 Lo = ExpandLibCall("__fixdfdi", Node, Hi);
1700 case ISD::FP_TO_UINT:
1701 if (Node->getOperand(0).getValueType() == MVT::f32)
1702 Lo = ExpandLibCall("__fixunssfdi", Node, Hi);
1704 Lo = ExpandLibCall("__fixunsdfdi", Node, Hi);
1708 // If we can emit an efficient shift operation, do so now.
1709 if (ExpandShift(ISD::SHL, Node->getOperand(0), Node->getOperand(1), Lo, Hi))
1711 // Otherwise, emit a libcall.
1712 Lo = ExpandLibCall("__ashldi3", Node, Hi);
1716 // If we can emit an efficient shift operation, do so now.
1717 if (ExpandShift(ISD::SRA, Node->getOperand(0), Node->getOperand(1), Lo, Hi))
1719 // Otherwise, emit a libcall.
1720 Lo = ExpandLibCall("__ashrdi3", Node, Hi);
1723 // If we can emit an efficient shift operation, do so now.
1724 if (ExpandShift(ISD::SRL, Node->getOperand(0), Node->getOperand(1), Lo, Hi))
1726 // Otherwise, emit a libcall.
1727 Lo = ExpandLibCall("__lshrdi3", Node, Hi);
1731 ExpandAddSub(true, Node->getOperand(0), Node->getOperand(1), Lo, Hi);
1734 ExpandAddSub(false, Node->getOperand(0), Node->getOperand(1), Lo, Hi);
1736 case ISD::MUL: Lo = ExpandLibCall("__muldi3" , Node, Hi); break;
1737 case ISD::SDIV: Lo = ExpandLibCall("__divdi3" , Node, Hi); break;
1738 case ISD::UDIV: Lo = ExpandLibCall("__udivdi3", Node, Hi); break;
1739 case ISD::SREM: Lo = ExpandLibCall("__moddi3" , Node, Hi); break;
1740 case ISD::UREM: Lo = ExpandLibCall("__umoddi3", Node, Hi); break;
1743 // Remember in a map if the values will be reused later.
1744 if (!Node->hasOneUse()) {
1745 bool isNew = ExpandedNodes.insert(std::make_pair(Op,
1746 std::make_pair(Lo, Hi))).second;
1747 assert(isNew && "Value already expanded?!?");
1752 // SelectionDAG::Legalize - This is the entry point for the file.
1754 void SelectionDAG::Legalize() {
1755 /// run - This is the main entry point to this class.
1757 SelectionDAGLegalize(*this).Run();