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);
521 switch (getTypeAction(Node->getOperand(1).getValueType())) {
523 SDOperand Val = LegalizeOp(Node->getOperand(1));
524 if (Val != Node->getOperand(1) || Tmp1 != Node->getOperand(0) ||
525 Tmp2 != Node->getOperand(2))
526 Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Val, Tmp2);
530 // Truncate the value and store the result.
531 Tmp3 = PromoteOp(Node->getOperand(1));
532 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, Tmp1, Tmp3, Tmp2,
533 Node->getOperand(1).getValueType());
538 ExpandOp(Node->getOperand(1), Lo, Hi);
540 if (!TLI.isLittleEndian())
543 Lo = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Lo, Tmp2);
545 unsigned IncrementSize = MVT::getSizeInBits(Hi.getValueType())/8;
546 Tmp2 = DAG.getNode(ISD::ADD, Tmp2.getValueType(), Tmp2,
547 getIntPtrConstant(IncrementSize));
548 assert(isTypeLegal(Tmp2.getValueType()) &&
549 "Pointers must be legal!");
550 Hi = DAG.getNode(ISD::STORE, MVT::Other, Tmp1, Hi, Tmp2);
551 Result = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo, Hi);
555 case ISD::TRUNCSTORE:
556 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
557 Tmp3 = LegalizeOp(Node->getOperand(2)); // Legalize the pointer.
559 switch (getTypeAction(Node->getOperand(1).getValueType())) {
561 Tmp2 = LegalizeOp(Node->getOperand(1));
562 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) ||
563 Tmp3 != Node->getOperand(2))
564 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, Tmp1, Tmp2, Tmp3,
565 cast<MVTSDNode>(Node)->getExtraValueType());
569 assert(0 && "Cannot handle illegal TRUNCSTORE yet!");
573 switch (getTypeAction(Node->getOperand(0).getValueType())) {
574 case Expand: assert(0 && "It's impossible to expand bools");
576 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the condition.
579 Tmp1 = PromoteOp(Node->getOperand(0)); // Promote the condition.
582 Tmp2 = LegalizeOp(Node->getOperand(1)); // TrueVal
583 Tmp3 = LegalizeOp(Node->getOperand(2)); // FalseVal
585 switch (TLI.getOperationAction(Node->getOpcode(), Tmp2.getValueType())) {
586 default: assert(0 && "This action is not supported yet!");
587 case TargetLowering::Legal:
588 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) ||
589 Tmp3 != Node->getOperand(2))
590 Result = DAG.getNode(ISD::SELECT, Node->getValueType(0),
593 case TargetLowering::Promote: {
595 TLI.getTypeToPromoteTo(ISD::SELECT, Tmp2.getValueType());
596 unsigned ExtOp, TruncOp;
597 if (MVT::isInteger(Tmp2.getValueType())) {
598 ExtOp = ISD::ZERO_EXTEND;
599 TruncOp = ISD::TRUNCATE;
601 ExtOp = ISD::FP_EXTEND;
602 TruncOp = ISD::FP_ROUND;
604 // Promote each of the values to the new type.
605 Tmp2 = DAG.getNode(ExtOp, NVT, Tmp2);
606 Tmp3 = DAG.getNode(ExtOp, NVT, Tmp3);
607 // Perform the larger operation, then round down.
608 Result = DAG.getNode(ISD::SELECT, NVT, Tmp1, Tmp2,Tmp3);
609 Result = DAG.getNode(TruncOp, Node->getValueType(0), Result);
615 switch (getTypeAction(Node->getOperand(0).getValueType())) {
617 Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS
618 Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS
619 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1))
620 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
621 Node->getValueType(0), Tmp1, Tmp2);
624 Tmp1 = PromoteOp(Node->getOperand(0)); // LHS
625 Tmp2 = PromoteOp(Node->getOperand(1)); // RHS
627 // If this is an FP compare, the operands have already been extended.
628 if (MVT::isInteger(Node->getOperand(0).getValueType())) {
629 MVT::ValueType VT = Node->getOperand(0).getValueType();
630 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT);
632 // Otherwise, we have to insert explicit sign or zero extends. Note
633 // that we could insert sign extends for ALL conditions, but zero extend
634 // is cheaper on many machines (an AND instead of two shifts), so prefer
636 switch (cast<SetCCSDNode>(Node)->getCondition()) {
637 default: assert(0 && "Unknown integer comparison!");
644 // ALL of these operations will work if we either sign or zero extend
645 // the operands (including the unsigned comparisons!). Zero extend is
646 // usually a simpler/cheaper operation, so prefer it.
647 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT);
648 Tmp2 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp2, VT);
654 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT);
655 Tmp2 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp2, VT);
660 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
661 Node->getValueType(0), Tmp1, Tmp2);
664 SDOperand LHSLo, LHSHi, RHSLo, RHSHi;
665 ExpandOp(Node->getOperand(0), LHSLo, LHSHi);
666 ExpandOp(Node->getOperand(1), RHSLo, RHSHi);
667 switch (cast<SetCCSDNode>(Node)->getCondition()) {
670 Tmp1 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSLo, RHSLo);
671 Tmp2 = DAG.getNode(ISD::XOR, LHSLo.getValueType(), LHSHi, RHSHi);
672 Tmp1 = DAG.getNode(ISD::OR, Tmp1.getValueType(), Tmp1, Tmp2);
673 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
674 Node->getValueType(0), Tmp1,
675 DAG.getConstant(0, Tmp1.getValueType()));
678 // FIXME: This generated code sucks.
680 switch (cast<SetCCSDNode>(Node)->getCondition()) {
681 default: assert(0 && "Unknown integer setcc!");
683 case ISD::SETULT: LowCC = ISD::SETULT; break;
685 case ISD::SETUGT: LowCC = ISD::SETUGT; break;
687 case ISD::SETULE: LowCC = ISD::SETULE; break;
689 case ISD::SETUGE: LowCC = ISD::SETUGE; break;
692 // Tmp1 = lo(op1) < lo(op2) // Always unsigned comparison
693 // Tmp2 = hi(op1) < hi(op2) // Signedness depends on operands
694 // dest = hi(op1) == hi(op2) ? Tmp1 : Tmp2;
696 // NOTE: on targets without efficient SELECT of bools, we can always use
697 // this identity: (B1 ? B2 : B3) --> (B1 & B2)|(!B1&B3)
698 Tmp1 = DAG.getSetCC(LowCC, Node->getValueType(0), LHSLo, RHSLo);
699 Tmp2 = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
700 Node->getValueType(0), LHSHi, RHSHi);
701 Result = DAG.getSetCC(ISD::SETEQ, Node->getValueType(0), LHSHi, RHSHi);
702 Result = DAG.getNode(ISD::SELECT, Tmp1.getValueType(),
712 Tmp1 = LegalizeOp(Node->getOperand(0)); // Chain
713 Tmp2 = LegalizeOp(Node->getOperand(1)); // Pointer
715 if (Node->getOpcode() == ISD::MEMSET) { // memset = ubyte
716 switch (getTypeAction(Node->getOperand(2).getValueType())) {
717 case Expand: assert(0 && "Cannot expand a byte!");
719 Tmp3 = LegalizeOp(Node->getOperand(2));
722 Tmp3 = PromoteOp(Node->getOperand(2));
726 Tmp3 = LegalizeOp(Node->getOperand(2)); // memcpy/move = pointer,
730 switch (getTypeAction(Node->getOperand(3).getValueType())) {
731 case Expand: assert(0 && "Cannot expand this yet!");
733 Tmp4 = LegalizeOp(Node->getOperand(3));
736 Tmp4 = PromoteOp(Node->getOperand(3));
741 switch (getTypeAction(Node->getOperand(4).getValueType())) { // uint
742 case Expand: assert(0 && "Cannot expand this yet!");
744 Tmp5 = LegalizeOp(Node->getOperand(4));
747 Tmp5 = PromoteOp(Node->getOperand(4));
751 switch (TLI.getOperationAction(Node->getOpcode(), MVT::Other)) {
752 default: assert(0 && "This action not implemented for this operation!");
753 case TargetLowering::Legal:
754 if (Tmp1 != Node->getOperand(0) || Tmp2 != Node->getOperand(1) ||
755 Tmp3 != Node->getOperand(2) || Tmp4 != Node->getOperand(3) ||
756 Tmp5 != Node->getOperand(4)) {
757 std::vector<SDOperand> Ops;
758 Ops.push_back(Tmp1); Ops.push_back(Tmp2); Ops.push_back(Tmp3);
759 Ops.push_back(Tmp4); Ops.push_back(Tmp5);
760 Result = DAG.getNode(Node->getOpcode(), MVT::Other, Ops);
763 case TargetLowering::Expand: {
764 // Otherwise, the target does not support this operation. Lower the
765 // operation to an explicit libcall as appropriate.
766 MVT::ValueType IntPtr = TLI.getPointerTy();
767 const Type *IntPtrTy = TLI.getTargetData().getIntPtrType();
768 std::vector<std::pair<SDOperand, const Type*> > Args;
770 const char *FnName = 0;
771 if (Node->getOpcode() == ISD::MEMSET) {
772 Args.push_back(std::make_pair(Tmp2, IntPtrTy));
773 // Extend the ubyte argument to be an int value for the call.
774 Tmp3 = DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Tmp3);
775 Args.push_back(std::make_pair(Tmp3, Type::IntTy));
776 Args.push_back(std::make_pair(Tmp4, IntPtrTy));
779 } else if (Node->getOpcode() == ISD::MEMCPY ||
780 Node->getOpcode() == ISD::MEMMOVE) {
781 Args.push_back(std::make_pair(Tmp2, IntPtrTy));
782 Args.push_back(std::make_pair(Tmp3, IntPtrTy));
783 Args.push_back(std::make_pair(Tmp4, IntPtrTy));
784 FnName = Node->getOpcode() == ISD::MEMMOVE ? "memmove" : "memcpy";
786 assert(0 && "Unknown op!");
788 std::pair<SDOperand,SDOperand> CallResult =
789 TLI.LowerCallTo(Tmp1, Type::VoidTy,
790 DAG.getExternalSymbol(FnName, IntPtr), Args, DAG);
791 Result = LegalizeOp(CallResult.second);
794 case TargetLowering::Custom:
795 std::vector<SDOperand> Ops;
796 Ops.push_back(Tmp1); Ops.push_back(Tmp2); Ops.push_back(Tmp3);
797 Ops.push_back(Tmp4); Ops.push_back(Tmp5);
798 Result = DAG.getNode(Node->getOpcode(), MVT::Other, Ops);
799 Result = TLI.LowerOperation(Result);
800 Result = LegalizeOp(Result);
806 case ISD::SUB_PARTS: {
807 std::vector<SDOperand> Ops;
808 bool Changed = false;
809 for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
810 Ops.push_back(LegalizeOp(Node->getOperand(i)));
811 Changed |= Ops.back() != Node->getOperand(i);
814 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Ops);
830 Tmp1 = LegalizeOp(Node->getOperand(0)); // LHS
831 Tmp2 = LegalizeOp(Node->getOperand(1)); // RHS
832 if (Tmp1 != Node->getOperand(0) ||
833 Tmp2 != Node->getOperand(1))
834 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1,Tmp2);
836 case ISD::ZERO_EXTEND:
837 case ISD::SIGN_EXTEND:
841 case ISD::FP_TO_SINT:
842 case ISD::FP_TO_UINT:
843 case ISD::SINT_TO_FP:
844 case ISD::UINT_TO_FP:
845 switch (getTypeAction(Node->getOperand(0).getValueType())) {
847 Tmp1 = LegalizeOp(Node->getOperand(0));
848 if (Tmp1 != Node->getOperand(0))
849 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1);
852 if (Node->getOpcode() == ISD::SINT_TO_FP ||
853 Node->getOpcode() == ISD::UINT_TO_FP) {
854 Result = ExpandIntToFP(Node->getOpcode() == ISD::SINT_TO_FP,
855 Node->getValueType(0), Node->getOperand(0));
856 Result = LegalizeOp(Result);
859 // In the expand case, we must be dealing with a truncate, because
860 // otherwise the result would be larger than the source.
861 assert(Node->getOpcode() == ISD::TRUNCATE &&
862 "Shouldn't need to expand other operators here!");
863 ExpandOp(Node->getOperand(0), Tmp1, Tmp2);
865 // Since the result is legal, we should just be able to truncate the low
866 // part of the source.
867 Result = DAG.getNode(ISD::TRUNCATE, Node->getValueType(0), Tmp1);
871 switch (Node->getOpcode()) {
872 case ISD::ZERO_EXTEND:
873 Result = PromoteOp(Node->getOperand(0));
874 // NOTE: Any extend would work here...
875 Result = DAG.getNode(ISD::ZERO_EXTEND, Op.getValueType(), Result);
876 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, Op.getValueType(),
877 Result, Node->getOperand(0).getValueType());
879 case ISD::SIGN_EXTEND:
880 Result = PromoteOp(Node->getOperand(0));
881 // NOTE: Any extend would work here...
882 Result = DAG.getNode(ISD::ZERO_EXTEND, Op.getValueType(), Result);
883 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(),
884 Result, Node->getOperand(0).getValueType());
887 Result = PromoteOp(Node->getOperand(0));
888 Result = DAG.getNode(ISD::TRUNCATE, Op.getValueType(), Result);
891 Result = PromoteOp(Node->getOperand(0));
892 if (Result.getValueType() != Op.getValueType())
893 // Dynamically dead while we have only 2 FP types.
894 Result = DAG.getNode(ISD::FP_EXTEND, Op.getValueType(), Result);
897 case ISD::FP_TO_SINT:
898 case ISD::FP_TO_UINT:
899 Result = PromoteOp(Node->getOperand(0));
900 Result = DAG.getNode(Node->getOpcode(), Op.getValueType(), Result);
902 case ISD::SINT_TO_FP:
903 Result = PromoteOp(Node->getOperand(0));
904 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(),
905 Result, Node->getOperand(0).getValueType());
906 Result = DAG.getNode(ISD::SINT_TO_FP, Op.getValueType(), Result);
908 case ISD::UINT_TO_FP:
909 Result = PromoteOp(Node->getOperand(0));
910 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, Result.getValueType(),
911 Result, Node->getOperand(0).getValueType());
912 Result = DAG.getNode(ISD::UINT_TO_FP, Op.getValueType(), Result);
917 case ISD::FP_ROUND_INREG:
918 case ISD::SIGN_EXTEND_INREG:
919 case ISD::ZERO_EXTEND_INREG: {
920 Tmp1 = LegalizeOp(Node->getOperand(0));
921 MVT::ValueType ExtraVT = cast<MVTSDNode>(Node)->getExtraValueType();
923 // If this operation is not supported, convert it to a shl/shr or load/store
925 switch (TLI.getOperationAction(Node->getOpcode(), ExtraVT)) {
926 default: assert(0 && "This action not supported for this op yet!");
927 case TargetLowering::Legal:
928 if (Tmp1 != Node->getOperand(0))
929 Result = DAG.getNode(Node->getOpcode(), Node->getValueType(0), Tmp1,
932 case TargetLowering::Expand:
933 // If this is an integer extend and shifts are supported, do that.
934 if (Node->getOpcode() == ISD::ZERO_EXTEND_INREG) {
935 // NOTE: we could fall back on load/store here too for targets without
936 // AND. However, it is doubtful that any exist.
937 // AND out the appropriate bits.
939 DAG.getConstant((1ULL << MVT::getSizeInBits(ExtraVT))-1,
940 Node->getValueType(0));
941 Result = DAG.getNode(ISD::AND, Node->getValueType(0),
942 Node->getOperand(0), Mask);
943 } else if (Node->getOpcode() == ISD::SIGN_EXTEND_INREG) {
944 // NOTE: we could fall back on load/store here too for targets without
945 // SAR. However, it is doubtful that any exist.
946 unsigned BitsDiff = MVT::getSizeInBits(Node->getValueType(0)) -
947 MVT::getSizeInBits(ExtraVT);
948 SDOperand ShiftCst = DAG.getConstant(BitsDiff, TLI.getShiftAmountTy());
949 Result = DAG.getNode(ISD::SHL, Node->getValueType(0),
950 Node->getOperand(0), ShiftCst);
951 Result = DAG.getNode(ISD::SRA, Node->getValueType(0),
953 } else if (Node->getOpcode() == ISD::FP_ROUND_INREG) {
954 // The only way we can lower this is to turn it into a STORETRUNC,
955 // EXTLOAD pair, targetting a temporary location (a stack slot).
957 // NOTE: there is a choice here between constantly creating new stack
958 // slots and always reusing the same one. We currently always create
959 // new ones, as reuse may inhibit scheduling.
960 const Type *Ty = MVT::getTypeForValueType(ExtraVT);
961 unsigned TySize = (unsigned)TLI.getTargetData().getTypeSize(Ty);
962 unsigned Align = TLI.getTargetData().getTypeAlignment(Ty);
963 MachineFunction &MF = DAG.getMachineFunction();
965 MF.getFrameInfo()->CreateStackObject((unsigned)TySize, Align);
966 SDOperand StackSlot = DAG.getFrameIndex(SSFI, TLI.getPointerTy());
967 Result = DAG.getNode(ISD::TRUNCSTORE, MVT::Other, DAG.getEntryNode(),
968 Node->getOperand(0), StackSlot, ExtraVT);
969 Result = DAG.getNode(ISD::EXTLOAD, Node->getValueType(0),
970 Result, StackSlot, ExtraVT);
972 assert(0 && "Unknown op");
974 Result = LegalizeOp(Result);
981 if (!Op.Val->hasOneUse())
982 AddLegalizedOperand(Op, Result);
987 /// PromoteOp - Given an operation that produces a value in an invalid type,
988 /// promote it to compute the value into a larger type. The produced value will
989 /// have the correct bits for the low portion of the register, but no guarantee
990 /// is made about the top bits: it may be zero, sign-extended, or garbage.
991 SDOperand SelectionDAGLegalize::PromoteOp(SDOperand Op) {
992 MVT::ValueType VT = Op.getValueType();
993 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT);
994 assert(getTypeAction(VT) == Promote &&
995 "Caller should expand or legalize operands that are not promotable!");
996 assert(NVT > VT && MVT::isInteger(NVT) == MVT::isInteger(VT) &&
997 "Cannot promote to smaller type!");
999 std::map<SDOperand, SDOperand>::iterator I = PromotedNodes.find(Op);
1000 if (I != PromotedNodes.end()) return I->second;
1002 SDOperand Tmp1, Tmp2, Tmp3;
1005 SDNode *Node = Op.Val;
1007 // Promotion needs an optimization step to clean up after it, and is not
1008 // careful to avoid operations the target does not support. Make sure that
1009 // all generated operations are legalized in the next iteration.
1010 NeedsAnotherIteration = true;
1012 switch (Node->getOpcode()) {
1014 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n";
1015 assert(0 && "Do not know how to promote this operator!");
1018 Result = DAG.getNode(ISD::ZERO_EXTEND, NVT, Op);
1019 assert(isa<ConstantSDNode>(Result) && "Didn't constant fold zext?");
1021 case ISD::ConstantFP:
1022 Result = DAG.getNode(ISD::FP_EXTEND, NVT, Op);
1023 assert(isa<ConstantFPSDNode>(Result) && "Didn't constant fold fp_extend?");
1025 case ISD::CopyFromReg:
1026 Result = DAG.getCopyFromReg(cast<RegSDNode>(Node)->getReg(), NVT,
1027 Node->getOperand(0));
1028 // Remember that we legalized the chain.
1029 AddLegalizedOperand(Op.getValue(1), Result.getValue(1));
1033 assert(getTypeAction(TLI.getSetCCResultTy()) == Legal &&
1034 "SetCC type is not legal??");
1035 Result = DAG.getSetCC(cast<SetCCSDNode>(Node)->getCondition(),
1036 TLI.getSetCCResultTy(), Node->getOperand(0),
1037 Node->getOperand(1));
1038 Result = LegalizeOp(Result);
1042 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1044 Result = LegalizeOp(Node->getOperand(0));
1045 assert(Result.getValueType() >= NVT &&
1046 "This truncation doesn't make sense!");
1047 if (Result.getValueType() > NVT) // Truncate to NVT instead of VT
1048 Result = DAG.getNode(ISD::TRUNCATE, NVT, Result);
1051 // The truncation is not required, because we don't guarantee anything
1052 // about high bits anyway.
1053 Result = PromoteOp(Node->getOperand(0));
1056 assert(0 && "Cannot handle expand yet");
1059 case ISD::SIGN_EXTEND:
1060 case ISD::ZERO_EXTEND:
1061 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1062 case Expand: assert(0 && "BUG: Smaller reg should have been promoted!");
1064 // Input is legal? Just do extend all the way to the larger type.
1065 Result = LegalizeOp(Node->getOperand(0));
1066 Result = DAG.getNode(Node->getOpcode(), NVT, Result);
1069 // Promote the reg if it's smaller.
1070 Result = PromoteOp(Node->getOperand(0));
1071 // The high bits are not guaranteed to be anything. Insert an extend.
1072 if (Node->getOpcode() == ISD::SIGN_EXTEND)
1073 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Result,
1074 Node->getOperand(0).getValueType());
1076 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Result,
1077 Node->getOperand(0).getValueType());
1082 case ISD::FP_EXTEND:
1083 assert(0 && "Case not implemented. Dynamically dead with 2 FP types!");
1085 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1086 case Expand: assert(0 && "BUG: Cannot expand FP regs!");
1087 case Promote: assert(0 && "Unreachable with 2 FP types!");
1089 // Input is legal? Do an FP_ROUND_INREG.
1090 Result = LegalizeOp(Node->getOperand(0));
1091 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT);
1096 case ISD::SINT_TO_FP:
1097 case ISD::UINT_TO_FP:
1098 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1100 Result = LegalizeOp(Node->getOperand(0));
1101 // No extra round required here.
1102 Result = DAG.getNode(Node->getOpcode(), NVT, Result);
1106 Result = PromoteOp(Node->getOperand(0));
1107 if (Node->getOpcode() == ISD::SINT_TO_FP)
1108 Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, Result.getValueType(),
1109 Result, Node->getOperand(0).getValueType());
1111 Result = DAG.getNode(ISD::ZERO_EXTEND_INREG, Result.getValueType(),
1112 Result, Node->getOperand(0).getValueType());
1113 // No extra round required here.
1114 Result = DAG.getNode(Node->getOpcode(), NVT, Result);
1117 Result = ExpandIntToFP(Node->getOpcode() == ISD::SINT_TO_FP, NVT,
1118 Node->getOperand(0));
1119 Result = LegalizeOp(Result);
1121 // Round if we cannot tolerate excess precision.
1122 if (NoExcessFPPrecision)
1123 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT);
1128 case ISD::FP_TO_SINT:
1129 case ISD::FP_TO_UINT:
1130 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1132 Tmp1 = LegalizeOp(Node->getOperand(0));
1135 // The input result is prerounded, so we don't have to do anything
1137 Tmp1 = PromoteOp(Node->getOperand(0));
1140 assert(0 && "not implemented");
1142 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1);
1151 // The input may have strange things in the top bits of the registers, but
1152 // these operations don't care. They may have wierd bits going out, but
1153 // that too is okay if they are integer operations.
1154 Tmp1 = PromoteOp(Node->getOperand(0));
1155 Tmp2 = PromoteOp(Node->getOperand(1));
1156 assert(Tmp1.getValueType() == NVT && Tmp2.getValueType() == NVT);
1157 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2);
1159 // However, if this is a floating point operation, they will give excess
1160 // precision that we may not be able to tolerate. If we DO allow excess
1161 // precision, just leave it, otherwise excise it.
1162 // FIXME: Why would we need to round FP ops more than integer ones?
1163 // Is Round(Add(Add(A,B),C)) != Round(Add(Round(Add(A,B)), C))
1164 if (MVT::isFloatingPoint(NVT) && NoExcessFPPrecision)
1165 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT);
1170 // These operators require that their input be sign extended.
1171 Tmp1 = PromoteOp(Node->getOperand(0));
1172 Tmp2 = PromoteOp(Node->getOperand(1));
1173 if (MVT::isInteger(NVT)) {
1174 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT);
1175 Tmp2 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp2, VT);
1177 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2);
1179 // Perform FP_ROUND: this is probably overly pessimistic.
1180 if (MVT::isFloatingPoint(NVT) && NoExcessFPPrecision)
1181 Result = DAG.getNode(ISD::FP_ROUND_INREG, NVT, Result, VT);
1186 // These operators require that their input be zero extended.
1187 Tmp1 = PromoteOp(Node->getOperand(0));
1188 Tmp2 = PromoteOp(Node->getOperand(1));
1189 assert(MVT::isInteger(NVT) && "Operators don't apply to FP!");
1190 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT);
1191 Tmp2 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp2, VT);
1192 Result = DAG.getNode(Node->getOpcode(), NVT, Tmp1, Tmp2);
1196 Tmp1 = PromoteOp(Node->getOperand(0));
1197 Tmp2 = LegalizeOp(Node->getOperand(1));
1198 Result = DAG.getNode(ISD::SHL, NVT, Tmp1, Tmp2);
1201 // The input value must be properly sign extended.
1202 Tmp1 = PromoteOp(Node->getOperand(0));
1203 Tmp1 = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Tmp1, VT);
1204 Tmp2 = LegalizeOp(Node->getOperand(1));
1205 Result = DAG.getNode(ISD::SRA, NVT, Tmp1, Tmp2);
1208 // The input value must be properly zero extended.
1209 Tmp1 = PromoteOp(Node->getOperand(0));
1210 Tmp1 = DAG.getNode(ISD::ZERO_EXTEND_INREG, NVT, Tmp1, VT);
1211 Tmp2 = LegalizeOp(Node->getOperand(1));
1212 Result = DAG.getNode(ISD::SRL, NVT, Tmp1, Tmp2);
1215 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
1216 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the pointer.
1217 Result = DAG.getNode(ISD::EXTLOAD, NVT, Tmp1, Tmp2, VT);
1219 // Remember that we legalized the chain.
1220 AddLegalizedOperand(Op.getValue(1), Result.getValue(1));
1223 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1224 case Expand: assert(0 && "It's impossible to expand bools");
1226 Tmp1 = LegalizeOp(Node->getOperand(0));// Legalize the condition.
1229 Tmp1 = PromoteOp(Node->getOperand(0)); // Promote the condition.
1232 Tmp2 = PromoteOp(Node->getOperand(1)); // Legalize the op0
1233 Tmp3 = PromoteOp(Node->getOperand(2)); // Legalize the op1
1234 Result = DAG.getNode(ISD::SELECT, NVT, Tmp1, Tmp2, Tmp3);
1237 Tmp1 = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
1238 Tmp2 = LegalizeOp(Node->getOperand(1)); // Legalize the callee.
1240 std::vector<SDOperand> Ops;
1241 for (unsigned i = 2, e = Node->getNumOperands(); i != e; ++i)
1242 Ops.push_back(LegalizeOp(Node->getOperand(i)));
1244 assert(Node->getNumValues() == 2 && Op.ResNo == 0 &&
1245 "Can only promote single result calls");
1246 std::vector<MVT::ValueType> RetTyVTs;
1247 RetTyVTs.reserve(2);
1248 RetTyVTs.push_back(NVT);
1249 RetTyVTs.push_back(MVT::Other);
1250 SDNode *NC = DAG.getCall(RetTyVTs, Tmp1, Tmp2, Ops);
1251 Result = SDOperand(NC, 0);
1253 // Insert the new chain mapping.
1254 AddLegalizedOperand(Op.getValue(1), Result.getValue(1));
1259 assert(Result.Val && "Didn't set a result!");
1260 AddPromotedOperand(Op, Result);
1264 /// ExpandAddSub - Find a clever way to expand this add operation into
1266 void SelectionDAGLegalize::ExpandAddSub(bool isAdd, SDOperand LHS,SDOperand RHS,
1267 SDOperand &Lo, SDOperand &Hi) {
1268 // Expand the subcomponents.
1269 SDOperand LHSL, LHSH, RHSL, RHSH;
1270 ExpandOp(LHS, LHSL, LHSH);
1271 ExpandOp(RHS, RHSL, RHSH);
1273 // Convert this add to the appropriate ADDC pair. The low part has no carry
1275 unsigned Opc = isAdd ? ISD::ADD_PARTS : ISD::SUB_PARTS;
1276 std::vector<SDOperand> Ops;
1277 Ops.push_back(LHSL);
1278 Ops.push_back(LHSH);
1279 Ops.push_back(RHSL);
1280 Ops.push_back(RHSH);
1281 Lo = DAG.getNode(Opc, LHSL.getValueType(), Ops);
1282 Hi = Lo.getValue(1);
1285 /// ExpandShift - Try to find a clever way to expand this shift operation out to
1286 /// smaller elements. If we can't find a way that is more efficient than a
1287 /// libcall on this target, return false. Otherwise, return true with the
1288 /// low-parts expanded into Lo and Hi.
1289 bool SelectionDAGLegalize::ExpandShift(unsigned Opc, SDOperand Op,SDOperand Amt,
1290 SDOperand &Lo, SDOperand &Hi) {
1291 assert((Opc == ISD::SHL || Opc == ISD::SRA || Opc == ISD::SRL) &&
1292 "This is not a shift!");
1293 MVT::ValueType NVT = TLI.getTypeToTransformTo(Op.getValueType());
1295 // If we have an efficient select operation (or if the selects will all fold
1296 // away), lower to some complex code, otherwise just emit the libcall.
1297 if (TLI.getOperationAction(ISD::SELECT, NVT) != TargetLowering::Legal &&
1298 !isa<ConstantSDNode>(Amt))
1302 ExpandOp(Op, InL, InH);
1303 SDOperand ShAmt = LegalizeOp(Amt);
1304 MVT::ValueType ShTy = ShAmt.getValueType();
1306 unsigned NVTBits = MVT::getSizeInBits(NVT);
1307 SDOperand NAmt = DAG.getNode(ISD::SUB, ShTy, // NAmt = 32-ShAmt
1308 DAG.getConstant(NVTBits, ShTy), ShAmt);
1310 // Compare the unmasked shift amount against 32.
1311 SDOperand Cond = DAG.getSetCC(ISD::SETGE, TLI.getSetCCResultTy(), ShAmt,
1312 DAG.getConstant(NVTBits, ShTy));
1314 if (TLI.getShiftAmountFlavor() != TargetLowering::Mask) {
1315 ShAmt = DAG.getNode(ISD::AND, ShTy, ShAmt, // ShAmt &= 31
1316 DAG.getConstant(NVTBits-1, ShTy));
1317 NAmt = DAG.getNode(ISD::AND, ShTy, NAmt, // NAmt &= 31
1318 DAG.getConstant(NVTBits-1, ShTy));
1321 if (Opc == ISD::SHL) {
1322 SDOperand T1 = DAG.getNode(ISD::OR, NVT,// T1 = (Hi << Amt) | (Lo >> NAmt)
1323 DAG.getNode(ISD::SHL, NVT, InH, ShAmt),
1324 DAG.getNode(ISD::SRL, NVT, InL, NAmt));
1325 SDOperand T2 = DAG.getNode(ISD::SHL, NVT, InL, ShAmt); // T2 = Lo << Amt&31
1327 Hi = DAG.getNode(ISD::SELECT, NVT, Cond, T2, T1);
1328 Lo = DAG.getNode(ISD::SELECT, NVT, Cond, DAG.getConstant(0, NVT), T2);
1330 SDOperand HiLoPart = DAG.getNode(ISD::SELECT, NVT,
1331 DAG.getSetCC(ISD::SETEQ,
1332 TLI.getSetCCResultTy(), NAmt,
1333 DAG.getConstant(32, ShTy)),
1334 DAG.getConstant(0, NVT),
1335 DAG.getNode(ISD::SHL, NVT, InH, NAmt));
1336 SDOperand T1 = DAG.getNode(ISD::OR, NVT,// T1 = (Hi << NAmt) | (Lo >> Amt)
1338 DAG.getNode(ISD::SRL, NVT, InL, ShAmt));
1339 SDOperand T2 = DAG.getNode(Opc, NVT, InH, ShAmt); // T2 = InH >> ShAmt&31
1342 if (Opc == ISD::SRA)
1343 HiPart = DAG.getNode(ISD::SRA, NVT, InH,
1344 DAG.getConstant(NVTBits-1, ShTy));
1346 HiPart = DAG.getConstant(0, NVT);
1347 Lo = DAG.getNode(ISD::SELECT, NVT, Cond, T2, T1);
1348 Hi = DAG.getNode(ISD::SELECT, NVT, Cond, HiPart, T2);
1353 /// FindLatestAdjCallStackDown - Scan up the dag to find the latest (highest
1354 /// NodeDepth) node that is an AdjCallStackDown operation and occurs later than
1356 static void FindLatestAdjCallStackDown(SDNode *Node, SDNode *&Found) {
1357 if (Node->getNodeDepth() <= Found->getNodeDepth()) return;
1359 // If we found an ADJCALLSTACKDOWN, we already know this node occurs later
1360 // than the Found node. Just remember this node and return.
1361 if (Node->getOpcode() == ISD::ADJCALLSTACKDOWN) {
1366 // Otherwise, scan the operands of Node to see if any of them is a call.
1367 assert(Node->getNumOperands() != 0 &&
1368 "All leaves should have depth equal to the entry node!");
1369 for (unsigned i = 0, e = Node->getNumOperands()-1; i != e; ++i)
1370 FindLatestAdjCallStackDown(Node->getOperand(i).Val, Found);
1372 // Tail recurse for the last iteration.
1373 FindLatestAdjCallStackDown(Node->getOperand(Node->getNumOperands()-1).Val,
1378 /// FindEarliestAdjCallStackUp - Scan down the dag to find the earliest (lowest
1379 /// NodeDepth) node that is an AdjCallStackUp operation and occurs more recent
1381 static void FindEarliestAdjCallStackUp(SDNode *Node, SDNode *&Found) {
1382 if (Found && Node->getNodeDepth() >= Found->getNodeDepth()) return;
1384 // If we found an ADJCALLSTACKUP, we already know this node occurs earlier
1385 // than the Found node. Just remember this node and return.
1386 if (Node->getOpcode() == ISD::ADJCALLSTACKUP) {
1391 // Otherwise, scan the operands of Node to see if any of them is a call.
1392 SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
1393 if (UI == E) return;
1394 for (--E; UI != E; ++UI)
1395 FindEarliestAdjCallStackUp(*UI, Found);
1397 // Tail recurse for the last iteration.
1398 FindEarliestAdjCallStackUp(*UI, Found);
1401 /// FindAdjCallStackUp - Given a chained node that is part of a call sequence,
1402 /// find the ADJCALLSTACKUP node that terminates the call sequence.
1403 static SDNode *FindAdjCallStackUp(SDNode *Node) {
1404 if (Node->getOpcode() == ISD::ADJCALLSTACKUP)
1406 assert(!Node->use_empty() && "Could not find ADJCALLSTACKUP!");
1408 if (Node->hasOneUse()) // Simple case, only has one user to check.
1409 return FindAdjCallStackUp(*Node->use_begin());
1411 SDOperand TheChain(Node, Node->getNumValues()-1);
1412 assert(TheChain.getValueType() == MVT::Other && "Is not a token chain!");
1414 for (SDNode::use_iterator UI = Node->use_begin(),
1415 E = Node->use_end(); ; ++UI) {
1416 assert(UI != E && "Didn't find a user of the tokchain, no ADJCALLSTACKUP!");
1418 // Make sure to only follow users of our token chain.
1420 for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i)
1421 if (User->getOperand(i) == TheChain)
1422 return FindAdjCallStackUp(User);
1424 assert(0 && "Unreachable");
1428 /// FindInputOutputChains - If we are replacing an operation with a call we need
1429 /// to find the call that occurs before and the call that occurs after it to
1430 /// properly serialize the calls in the block.
1431 static SDOperand FindInputOutputChains(SDNode *OpNode, SDNode *&OutChain,
1433 SDNode *LatestAdjCallStackDown = Entry.Val;
1434 FindLatestAdjCallStackDown(OpNode, LatestAdjCallStackDown);
1435 //std::cerr << "Found node: "; LatestAdjCallStackDown->dump(); std::cerr <<"\n";
1437 SDNode *LatestAdjCallStackUp = FindAdjCallStackUp(LatestAdjCallStackDown);
1440 SDNode *EarliestAdjCallStackUp = 0;
1441 FindEarliestAdjCallStackUp(OpNode, EarliestAdjCallStackUp);
1443 if (EarliestAdjCallStackUp) {
1444 //std::cerr << "Found node: ";
1445 //EarliestAdjCallStackUp->dump(); std::cerr <<"\n";
1448 return SDOperand(LatestAdjCallStackUp, 0);
1453 // ExpandLibCall - Expand a node into a call to a libcall. If the result value
1454 // does not fit into a register, return the lo part and set the hi part to the
1455 // by-reg argument. If it does fit into a single register, return the result
1456 // and leave the Hi part unset.
1457 SDOperand SelectionDAGLegalize::ExpandLibCall(const char *Name, SDNode *Node,
1460 SDOperand InChain = FindInputOutputChains(Node, OutChain,
1461 DAG.getEntryNode());
1462 // TODO. Link in chains.
1464 TargetLowering::ArgListTy Args;
1465 for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i) {
1466 MVT::ValueType ArgVT = Node->getOperand(i).getValueType();
1467 const Type *ArgTy = MVT::getTypeForValueType(ArgVT);
1468 Args.push_back(std::make_pair(Node->getOperand(i), ArgTy));
1470 SDOperand Callee = DAG.getExternalSymbol(Name, TLI.getPointerTy());
1472 // We don't care about token chains for libcalls. We just use the entry
1473 // node as our input and ignore the output chain. This allows us to place
1474 // calls wherever we need them to satisfy data dependences.
1475 const Type *RetTy = MVT::getTypeForValueType(Node->getValueType(0));
1476 SDOperand Result = TLI.LowerCallTo(InChain, RetTy, Callee,
1478 switch (getTypeAction(Result.getValueType())) {
1479 default: assert(0 && "Unknown thing");
1483 assert(0 && "Cannot promote this yet!");
1486 ExpandOp(Result, Lo, Hi);
1492 /// ExpandIntToFP - Expand a [US]INT_TO_FP operation, assuming that the
1493 /// destination type is legal.
1494 SDOperand SelectionDAGLegalize::
1495 ExpandIntToFP(bool isSigned, MVT::ValueType DestTy, SDOperand Source) {
1496 assert(getTypeAction(DestTy) == Legal && "Destination type is not legal!");
1497 assert(getTypeAction(Source.getValueType()) == Expand &&
1498 "This is not an expansion!");
1499 assert(Source.getValueType() == MVT::i64 && "Only handle expand from i64!");
1502 SDOperand InChain = FindInputOutputChains(Source.Val, OutChain,
1503 DAG.getEntryNode());
1505 const char *FnName = 0;
1507 if (DestTy == MVT::f32)
1508 FnName = "__floatdisf";
1510 assert(DestTy == MVT::f64 && "Unknown fp value type!");
1511 FnName = "__floatdidf";
1514 // If this is unsigned, and not supported, first perform the conversion to
1515 // signed, then adjust the result if the sign bit is set.
1516 SDOperand SignedConv = ExpandIntToFP(false, DestTy, Source);
1518 assert(0 && "Unsigned casts not supported yet!");
1520 SDOperand Callee = DAG.getExternalSymbol(FnName, TLI.getPointerTy());
1522 TargetLowering::ArgListTy Args;
1523 const Type *ArgTy = MVT::getTypeForValueType(Source.getValueType());
1524 Args.push_back(std::make_pair(Source, ArgTy));
1526 // We don't care about token chains for libcalls. We just use the entry
1527 // node as our input and ignore the output chain. This allows us to place
1528 // calls wherever we need them to satisfy data dependences.
1529 const Type *RetTy = MVT::getTypeForValueType(DestTy);
1530 return TLI.LowerCallTo(InChain, RetTy, Callee, Args, DAG).first;
1536 /// ExpandOp - Expand the specified SDOperand into its two component pieces
1537 /// Lo&Hi. Note that the Op MUST be an expanded type. As a result of this, the
1538 /// LegalizeNodes map is filled in for any results that are not expanded, the
1539 /// ExpandedNodes map is filled in for any results that are expanded, and the
1540 /// Lo/Hi values are returned.
1541 void SelectionDAGLegalize::ExpandOp(SDOperand Op, SDOperand &Lo, SDOperand &Hi){
1542 MVT::ValueType VT = Op.getValueType();
1543 MVT::ValueType NVT = TLI.getTypeToTransformTo(VT);
1544 SDNode *Node = Op.Val;
1545 assert(getTypeAction(VT) == Expand && "Not an expanded type!");
1546 assert(MVT::isInteger(VT) && "Cannot expand FP values!");
1547 assert(MVT::isInteger(NVT) && NVT < VT &&
1548 "Cannot expand to FP value or to larger int value!");
1550 // If there is more than one use of this, see if we already expanded it.
1551 // There is no use remembering values that only have a single use, as the map
1552 // entries will never be reused.
1553 if (!Node->hasOneUse()) {
1554 std::map<SDOperand, std::pair<SDOperand, SDOperand> >::iterator I
1555 = ExpandedNodes.find(Op);
1556 if (I != ExpandedNodes.end()) {
1557 Lo = I->second.first;
1558 Hi = I->second.second;
1563 // Expanding to multiple registers needs to perform an optimization step, and
1564 // is not careful to avoid operations the target does not support. Make sure
1565 // that all generated operations are legalized in the next iteration.
1566 NeedsAnotherIteration = true;
1568 switch (Node->getOpcode()) {
1570 std::cerr << "NODE: "; Node->dump(); std::cerr << "\n";
1571 assert(0 && "Do not know how to expand this operator!");
1573 case ISD::Constant: {
1574 uint64_t Cst = cast<ConstantSDNode>(Node)->getValue();
1575 Lo = DAG.getConstant(Cst, NVT);
1576 Hi = DAG.getConstant(Cst >> MVT::getSizeInBits(NVT), NVT);
1580 case ISD::CopyFromReg: {
1581 unsigned Reg = cast<RegSDNode>(Node)->getReg();
1582 // Aggregate register values are always in consequtive pairs.
1583 Lo = DAG.getCopyFromReg(Reg, NVT, Node->getOperand(0));
1584 Hi = DAG.getCopyFromReg(Reg+1, NVT, Lo.getValue(1));
1586 // Remember that we legalized the chain.
1587 AddLegalizedOperand(Op.getValue(1), Hi.getValue(1));
1589 assert(isTypeLegal(NVT) && "Cannot expand this multiple times yet!");
1594 SDOperand Ch = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
1595 SDOperand Ptr = LegalizeOp(Node->getOperand(1)); // Legalize the pointer.
1596 Lo = DAG.getLoad(NVT, Ch, Ptr);
1598 // Increment the pointer to the other half.
1599 unsigned IncrementSize = MVT::getSizeInBits(Lo.getValueType())/8;
1600 Ptr = DAG.getNode(ISD::ADD, Ptr.getValueType(), Ptr,
1601 getIntPtrConstant(IncrementSize));
1602 Hi = DAG.getLoad(NVT, Ch, Ptr);
1604 // Build a factor node to remember that this load is independent of the
1606 SDOperand TF = DAG.getNode(ISD::TokenFactor, MVT::Other, Lo.getValue(1),
1609 // Remember that we legalized the chain.
1610 AddLegalizedOperand(Op.getValue(1), TF);
1611 if (!TLI.isLittleEndian())
1616 SDOperand Chain = LegalizeOp(Node->getOperand(0)); // Legalize the chain.
1617 SDOperand Callee = LegalizeOp(Node->getOperand(1)); // Legalize the callee.
1619 bool Changed = false;
1620 std::vector<SDOperand> Ops;
1621 for (unsigned i = 2, e = Node->getNumOperands(); i != e; ++i) {
1622 Ops.push_back(LegalizeOp(Node->getOperand(i)));
1623 Changed |= Ops.back() != Node->getOperand(i);
1626 assert(Node->getNumValues() == 2 && Op.ResNo == 0 &&
1627 "Can only expand a call once so far, not i64 -> i16!");
1629 std::vector<MVT::ValueType> RetTyVTs;
1630 RetTyVTs.reserve(3);
1631 RetTyVTs.push_back(NVT);
1632 RetTyVTs.push_back(NVT);
1633 RetTyVTs.push_back(MVT::Other);
1634 SDNode *NC = DAG.getCall(RetTyVTs, Chain, Callee, Ops);
1635 Lo = SDOperand(NC, 0);
1636 Hi = SDOperand(NC, 1);
1638 // Insert the new chain mapping.
1639 AddLegalizedOperand(Op.getValue(1), Hi.getValue(2));
1644 case ISD::XOR: { // Simple logical operators -> two trivial pieces.
1645 SDOperand LL, LH, RL, RH;
1646 ExpandOp(Node->getOperand(0), LL, LH);
1647 ExpandOp(Node->getOperand(1), RL, RH);
1648 Lo = DAG.getNode(Node->getOpcode(), NVT, LL, RL);
1649 Hi = DAG.getNode(Node->getOpcode(), NVT, LH, RH);
1653 SDOperand C, LL, LH, RL, RH;
1655 switch (getTypeAction(Node->getOperand(0).getValueType())) {
1656 case Expand: assert(0 && "It's impossible to expand bools");
1658 C = LegalizeOp(Node->getOperand(0)); // Legalize the condition.
1661 C = PromoteOp(Node->getOperand(0)); // Promote the condition.
1664 ExpandOp(Node->getOperand(1), LL, LH);
1665 ExpandOp(Node->getOperand(2), RL, RH);
1666 Lo = DAG.getNode(ISD::SELECT, NVT, C, LL, RL);
1667 Hi = DAG.getNode(ISD::SELECT, NVT, C, LH, RH);
1670 case ISD::SIGN_EXTEND: {
1671 // The low part is just a sign extension of the input (which degenerates to
1673 Lo = DAG.getNode(ISD::SIGN_EXTEND, NVT, LegalizeOp(Node->getOperand(0)));
1675 // The high part is obtained by SRA'ing all but one of the bits of the lo
1677 unsigned LoSize = MVT::getSizeInBits(Lo.getValueType());
1678 Hi = DAG.getNode(ISD::SRA, NVT, Lo, DAG.getConstant(LoSize-1,
1679 TLI.getShiftAmountTy()));
1682 case ISD::ZERO_EXTEND:
1683 // The low part is just a zero extension of the input (which degenerates to
1685 Lo = DAG.getNode(ISD::ZERO_EXTEND, NVT, LegalizeOp(Node->getOperand(0)));
1687 // The high part is just a zero.
1688 Hi = DAG.getConstant(0, NVT);
1691 // These operators cannot be expanded directly, emit them as calls to
1692 // library functions.
1693 case ISD::FP_TO_SINT:
1694 if (Node->getOperand(0).getValueType() == MVT::f32)
1695 Lo = ExpandLibCall("__fixsfdi", Node, Hi);
1697 Lo = ExpandLibCall("__fixdfdi", Node, Hi);
1699 case ISD::FP_TO_UINT:
1700 if (Node->getOperand(0).getValueType() == MVT::f32)
1701 Lo = ExpandLibCall("__fixunssfdi", Node, Hi);
1703 Lo = ExpandLibCall("__fixunsdfdi", Node, Hi);
1707 // If we can emit an efficient shift operation, do so now.
1708 if (ExpandShift(ISD::SHL, Node->getOperand(0), Node->getOperand(1), Lo, Hi))
1710 // Otherwise, emit a libcall.
1711 Lo = ExpandLibCall("__ashldi3", Node, Hi);
1715 // If we can emit an efficient shift operation, do so now.
1716 if (ExpandShift(ISD::SRA, Node->getOperand(0), Node->getOperand(1), Lo, Hi))
1718 // Otherwise, emit a libcall.
1719 Lo = ExpandLibCall("__ashrdi3", Node, Hi);
1722 // If we can emit an efficient shift operation, do so now.
1723 if (ExpandShift(ISD::SRL, Node->getOperand(0), Node->getOperand(1), Lo, Hi))
1725 // Otherwise, emit a libcall.
1726 Lo = ExpandLibCall("__lshrdi3", Node, Hi);
1730 ExpandAddSub(true, Node->getOperand(0), Node->getOperand(1), Lo, Hi);
1733 ExpandAddSub(false, Node->getOperand(0), Node->getOperand(1), Lo, Hi);
1735 case ISD::MUL: Lo = ExpandLibCall("__muldi3" , Node, Hi); break;
1736 case ISD::SDIV: Lo = ExpandLibCall("__divdi3" , Node, Hi); break;
1737 case ISD::UDIV: Lo = ExpandLibCall("__udivdi3", Node, Hi); break;
1738 case ISD::SREM: Lo = ExpandLibCall("__moddi3" , Node, Hi); break;
1739 case ISD::UREM: Lo = ExpandLibCall("__umoddi3", Node, Hi); break;
1742 // Remember in a map if the values will be reused later.
1743 if (!Node->hasOneUse()) {
1744 bool isNew = ExpandedNodes.insert(std::make_pair(Op,
1745 std::make_pair(Lo, Hi))).second;
1746 assert(isNew && "Value already expanded?!?");
1751 // SelectionDAG::Legalize - This is the entry point for the file.
1753 void SelectionDAG::Legalize() {
1754 /// run - This is the main entry point to this class.
1756 SelectionDAGLegalize(*this).Run();