1 //===-- TargetLowering.cpp - Implement the TargetLowering class -----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This implements the TargetLowering class.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Target/TargetLowering.h"
15 #include "llvm/ADT/BitVector.h"
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/CodeGen/Analysis.h"
18 #include "llvm/CodeGen/MachineFrameInfo.h"
19 #include "llvm/CodeGen/MachineFunction.h"
20 #include "llvm/CodeGen/MachineJumpTableInfo.h"
21 #include "llvm/CodeGen/SelectionDAG.h"
22 #include "llvm/IR/DataLayout.h"
23 #include "llvm/IR/DerivedTypes.h"
24 #include "llvm/IR/GlobalVariable.h"
25 #include "llvm/IR/LLVMContext.h"
26 #include "llvm/MC/MCAsmInfo.h"
27 #include "llvm/MC/MCExpr.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/ErrorHandling.h"
30 #include "llvm/Support/MathExtras.h"
31 #include "llvm/Target/TargetLoweringObjectFile.h"
32 #include "llvm/Target/TargetMachine.h"
33 #include "llvm/Target/TargetRegisterInfo.h"
34 #include "llvm/Target/TargetSubtargetInfo.h"
38 /// NOTE: The TargetMachine owns TLOF.
39 TargetLowering::TargetLowering(const TargetMachine &tm)
40 : TargetLoweringBase(tm) {}
42 const char *TargetLowering::getTargetNodeName(unsigned Opcode) const {
46 /// Check whether a given call node is in tail position within its function. If
47 /// so, it sets Chain to the input chain of the tail call.
48 bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
49 SDValue &Chain) const {
50 const Function *F = DAG.getMachineFunction().getFunction();
52 // Conservatively require the attributes of the call to match those of
53 // the return. Ignore noalias because it doesn't affect the call sequence.
54 AttributeSet CallerAttrs = F->getAttributes();
55 if (AttrBuilder(CallerAttrs, AttributeSet::ReturnIndex)
56 .removeAttribute(Attribute::NoAlias).hasAttributes())
59 // It's not safe to eliminate the sign / zero extension of the return value.
60 if (CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::ZExt) ||
61 CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::SExt))
64 // Check if the only use is a function return node.
65 return isUsedByReturnOnly(Node, Chain);
68 /// \brief Set CallLoweringInfo attribute flags based on a call instruction
69 /// and called function attributes.
70 void TargetLowering::ArgListEntry::setAttributes(ImmutableCallSite *CS,
72 isSExt = CS->paramHasAttr(AttrIdx, Attribute::SExt);
73 isZExt = CS->paramHasAttr(AttrIdx, Attribute::ZExt);
74 isInReg = CS->paramHasAttr(AttrIdx, Attribute::InReg);
75 isSRet = CS->paramHasAttr(AttrIdx, Attribute::StructRet);
76 isNest = CS->paramHasAttr(AttrIdx, Attribute::Nest);
77 isByVal = CS->paramHasAttr(AttrIdx, Attribute::ByVal);
78 isInAlloca = CS->paramHasAttr(AttrIdx, Attribute::InAlloca);
79 isReturned = CS->paramHasAttr(AttrIdx, Attribute::Returned);
80 Alignment = CS->getParamAlignment(AttrIdx);
83 /// Generate a libcall taking the given operands as arguments and returning a
84 /// result of type RetVT.
85 std::pair<SDValue, SDValue>
86 TargetLowering::makeLibCall(SelectionDAG &DAG,
87 RTLIB::Libcall LC, EVT RetVT,
88 const SDValue *Ops, unsigned NumOps,
89 bool isSigned, SDLoc dl,
91 bool isReturnValueUsed) const {
92 TargetLowering::ArgListTy Args;
95 TargetLowering::ArgListEntry Entry;
96 for (unsigned i = 0; i != NumOps; ++i) {
98 Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext());
99 Entry.isSExt = shouldSignExtendTypeInLibCall(Ops[i].getValueType(), isSigned);
100 Entry.isZExt = !shouldSignExtendTypeInLibCall(Ops[i].getValueType(), isSigned);
101 Args.push_back(Entry);
103 if (LC == RTLIB::UNKNOWN_LIBCALL)
104 report_fatal_error("Unsupported library call operation!");
105 SDValue Callee = DAG.getExternalSymbol(getLibcallName(LC),
106 getPointerTy(DAG.getDataLayout()));
108 Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext());
109 TargetLowering::CallLoweringInfo CLI(DAG);
110 bool signExtend = shouldSignExtendTypeInLibCall(RetVT, isSigned);
111 CLI.setDebugLoc(dl).setChain(DAG.getEntryNode())
112 .setCallee(getLibcallCallingConv(LC), RetTy, Callee, std::move(Args), 0)
113 .setNoReturn(doesNotReturn).setDiscardResult(!isReturnValueUsed)
114 .setSExtResult(signExtend).setZExtResult(!signExtend);
115 return LowerCallTo(CLI);
119 /// SoftenSetCCOperands - Soften the operands of a comparison. This code is
120 /// shared among BR_CC, SELECT_CC, and SETCC handlers.
121 void TargetLowering::softenSetCCOperands(SelectionDAG &DAG, EVT VT,
122 SDValue &NewLHS, SDValue &NewRHS,
123 ISD::CondCode &CCCode,
125 assert((VT == MVT::f32 || VT == MVT::f64 || VT == MVT::f128)
126 && "Unsupported setcc type!");
128 // Expand into one or more soft-fp libcall(s).
129 RTLIB::Libcall LC1 = RTLIB::UNKNOWN_LIBCALL, LC2 = RTLIB::UNKNOWN_LIBCALL;
133 LC1 = (VT == MVT::f32) ? RTLIB::OEQ_F32 :
134 (VT == MVT::f64) ? RTLIB::OEQ_F64 : RTLIB::OEQ_F128;
138 LC1 = (VT == MVT::f32) ? RTLIB::UNE_F32 :
139 (VT == MVT::f64) ? RTLIB::UNE_F64 : RTLIB::UNE_F128;
143 LC1 = (VT == MVT::f32) ? RTLIB::OGE_F32 :
144 (VT == MVT::f64) ? RTLIB::OGE_F64 : RTLIB::OGE_F128;
148 LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
149 (VT == MVT::f64) ? RTLIB::OLT_F64 : RTLIB::OLT_F128;
153 LC1 = (VT == MVT::f32) ? RTLIB::OLE_F32 :
154 (VT == MVT::f64) ? RTLIB::OLE_F64 : RTLIB::OLE_F128;
158 LC1 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
159 (VT == MVT::f64) ? RTLIB::OGT_F64 : RTLIB::OGT_F128;
162 LC1 = (VT == MVT::f32) ? RTLIB::UO_F32 :
163 (VT == MVT::f64) ? RTLIB::UO_F64 : RTLIB::UO_F128;
166 LC1 = (VT == MVT::f32) ? RTLIB::O_F32 :
167 (VT == MVT::f64) ? RTLIB::O_F64 : RTLIB::O_F128;
170 LC1 = (VT == MVT::f32) ? RTLIB::UO_F32 :
171 (VT == MVT::f64) ? RTLIB::UO_F64 : RTLIB::UO_F128;
174 // SETONE = SETOLT | SETOGT
175 LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
176 (VT == MVT::f64) ? RTLIB::OLT_F64 : RTLIB::OLT_F128;
179 LC2 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
180 (VT == MVT::f64) ? RTLIB::OGT_F64 : RTLIB::OGT_F128;
183 LC2 = (VT == MVT::f32) ? RTLIB::OGE_F32 :
184 (VT == MVT::f64) ? RTLIB::OGE_F64 : RTLIB::OGE_F128;
187 LC2 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
188 (VT == MVT::f64) ? RTLIB::OLT_F64 : RTLIB::OLT_F128;
191 LC2 = (VT == MVT::f32) ? RTLIB::OLE_F32 :
192 (VT == MVT::f64) ? RTLIB::OLE_F64 : RTLIB::OLE_F128;
195 LC2 = (VT == MVT::f32) ? RTLIB::OEQ_F32 :
196 (VT == MVT::f64) ? RTLIB::OEQ_F64 : RTLIB::OEQ_F128;
198 default: llvm_unreachable("Do not know how to soften this setcc!");
202 // Use the target specific return value for comparions lib calls.
203 EVT RetVT = getCmpLibcallReturnType();
204 SDValue Ops[2] = { NewLHS, NewRHS };
205 NewLHS = makeLibCall(DAG, LC1, RetVT, Ops, 2, false/*sign irrelevant*/,
207 NewRHS = DAG.getConstant(0, dl, RetVT);
208 CCCode = getCmpLibcallCC(LC1);
209 if (LC2 != RTLIB::UNKNOWN_LIBCALL) {
210 SDValue Tmp = DAG.getNode(
212 getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), RetVT),
213 NewLHS, NewRHS, DAG.getCondCode(CCCode));
214 NewLHS = makeLibCall(DAG, LC2, RetVT, Ops, 2, false/*sign irrelevant*/,
216 NewLHS = DAG.getNode(
218 getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), RetVT),
219 NewLHS, NewRHS, DAG.getCondCode(getCmpLibcallCC(LC2)));
220 NewLHS = DAG.getNode(ISD::OR, dl, Tmp.getValueType(), Tmp, NewLHS);
225 /// getJumpTableEncoding - Return the entry encoding for a jump table in the
226 /// current function. The returned value is a member of the
227 /// MachineJumpTableInfo::JTEntryKind enum.
228 unsigned TargetLowering::getJumpTableEncoding() const {
229 // In non-pic modes, just use the address of a block.
230 if (getTargetMachine().getRelocationModel() != Reloc::PIC_)
231 return MachineJumpTableInfo::EK_BlockAddress;
233 // In PIC mode, if the target supports a GPRel32 directive, use it.
234 if (getTargetMachine().getMCAsmInfo()->getGPRel32Directive() != nullptr)
235 return MachineJumpTableInfo::EK_GPRel32BlockAddress;
237 // Otherwise, use a label difference.
238 return MachineJumpTableInfo::EK_LabelDifference32;
241 SDValue TargetLowering::getPICJumpTableRelocBase(SDValue Table,
242 SelectionDAG &DAG) const {
243 // If our PIC model is GP relative, use the global offset table as the base.
244 unsigned JTEncoding = getJumpTableEncoding();
246 if ((JTEncoding == MachineJumpTableInfo::EK_GPRel64BlockAddress) ||
247 (JTEncoding == MachineJumpTableInfo::EK_GPRel32BlockAddress))
248 return DAG.getGLOBAL_OFFSET_TABLE(getPointerTy(DAG.getDataLayout()));
253 /// getPICJumpTableRelocBaseExpr - This returns the relocation base for the
254 /// given PIC jumptable, the same as getPICJumpTableRelocBase, but as an
257 TargetLowering::getPICJumpTableRelocBaseExpr(const MachineFunction *MF,
258 unsigned JTI,MCContext &Ctx) const{
259 // The normal PIC reloc base is the label at the start of the jump table.
260 return MCSymbolRefExpr::create(MF->getJTISymbol(JTI, Ctx), Ctx);
264 TargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
265 // Assume that everything is safe in static mode.
266 if (getTargetMachine().getRelocationModel() == Reloc::Static)
269 // In dynamic-no-pic mode, assume that known defined values are safe.
270 if (getTargetMachine().getRelocationModel() == Reloc::DynamicNoPIC &&
271 GA && GA->getGlobal()->isStrongDefinitionForLinker())
274 // Otherwise assume nothing is safe.
278 //===----------------------------------------------------------------------===//
279 // Optimization Methods
280 //===----------------------------------------------------------------------===//
282 /// ShrinkDemandedConstant - Check to see if the specified operand of the
283 /// specified instruction is a constant integer. If so, check to see if there
284 /// are any bits set in the constant that are not demanded. If so, shrink the
285 /// constant and return true.
286 bool TargetLowering::TargetLoweringOpt::ShrinkDemandedConstant(SDValue Op,
287 const APInt &Demanded) {
290 // FIXME: ISD::SELECT, ISD::SELECT_CC
291 switch (Op.getOpcode()) {
296 ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
297 if (!C) return false;
299 if (Op.getOpcode() == ISD::XOR &&
300 (C->getAPIntValue() | (~Demanded)).isAllOnesValue())
303 // if we can expand it to have all bits set, do it
304 if (C->getAPIntValue().intersects(~Demanded)) {
305 EVT VT = Op.getValueType();
306 SDValue New = DAG.getNode(Op.getOpcode(), dl, VT, Op.getOperand(0),
307 DAG.getConstant(Demanded &
310 return CombineTo(Op, New);
320 /// ShrinkDemandedOp - Convert x+y to (VT)((SmallVT)x+(SmallVT)y) if the
321 /// casts are free. This uses isZExtFree and ZERO_EXTEND for the widening
322 /// cast, but it could be generalized for targets with other types of
323 /// implicit widening casts.
325 TargetLowering::TargetLoweringOpt::ShrinkDemandedOp(SDValue Op,
327 const APInt &Demanded,
329 assert(Op.getNumOperands() == 2 &&
330 "ShrinkDemandedOp only supports binary operators!");
331 assert(Op.getNode()->getNumValues() == 1 &&
332 "ShrinkDemandedOp only supports nodes with one result!");
334 // Early return, as this function cannot handle vector types.
335 if (Op.getValueType().isVector())
338 // Don't do this if the node has another user, which may require the
340 if (!Op.getNode()->hasOneUse())
343 // Search for the smallest integer type with free casts to and from
344 // Op's type. For expedience, just check power-of-2 integer types.
345 const TargetLowering &TLI = DAG.getTargetLoweringInfo();
346 unsigned DemandedSize = BitWidth - Demanded.countLeadingZeros();
347 unsigned SmallVTBits = DemandedSize;
348 if (!isPowerOf2_32(SmallVTBits))
349 SmallVTBits = NextPowerOf2(SmallVTBits);
350 for (; SmallVTBits < BitWidth; SmallVTBits = NextPowerOf2(SmallVTBits)) {
351 EVT SmallVT = EVT::getIntegerVT(*DAG.getContext(), SmallVTBits);
352 if (TLI.isTruncateFree(Op.getValueType(), SmallVT) &&
353 TLI.isZExtFree(SmallVT, Op.getValueType())) {
354 // We found a type with free casts.
355 SDValue X = DAG.getNode(Op.getOpcode(), dl, SmallVT,
356 DAG.getNode(ISD::TRUNCATE, dl, SmallVT,
357 Op.getNode()->getOperand(0)),
358 DAG.getNode(ISD::TRUNCATE, dl, SmallVT,
359 Op.getNode()->getOperand(1)));
360 bool NeedZext = DemandedSize > SmallVTBits;
361 SDValue Z = DAG.getNode(NeedZext ? ISD::ZERO_EXTEND : ISD::ANY_EXTEND,
362 dl, Op.getValueType(), X);
363 return CombineTo(Op, Z);
369 /// SimplifyDemandedBits - Look at Op. At this point, we know that only the
370 /// DemandedMask bits of the result of Op are ever used downstream. If we can
371 /// use this information to simplify Op, create a new simplified DAG node and
372 /// return true, returning the original and new nodes in Old and New. Otherwise,
373 /// analyze the expression and return a mask of KnownOne and KnownZero bits for
374 /// the expression (used to simplify the caller). The KnownZero/One bits may
375 /// only be accurate for those bits in the DemandedMask.
376 bool TargetLowering::SimplifyDemandedBits(SDValue Op,
377 const APInt &DemandedMask,
380 TargetLoweringOpt &TLO,
381 unsigned Depth) const {
382 unsigned BitWidth = DemandedMask.getBitWidth();
383 assert(Op.getValueType().getScalarType().getSizeInBits() == BitWidth &&
384 "Mask size mismatches value type size!");
385 APInt NewMask = DemandedMask;
387 auto &DL = TLO.DAG.getDataLayout();
389 // Don't know anything.
390 KnownZero = KnownOne = APInt(BitWidth, 0);
392 // Other users may use these bits.
393 if (!Op.getNode()->hasOneUse()) {
395 // If not at the root, Just compute the KnownZero/KnownOne bits to
396 // simplify things downstream.
397 TLO.DAG.computeKnownBits(Op, KnownZero, KnownOne, Depth);
400 // If this is the root being simplified, allow it to have multiple uses,
401 // just set the NewMask to all bits.
402 NewMask = APInt::getAllOnesValue(BitWidth);
403 } else if (DemandedMask == 0) {
404 // Not demanding any bits from Op.
405 if (Op.getOpcode() != ISD::UNDEF)
406 return TLO.CombineTo(Op, TLO.DAG.getUNDEF(Op.getValueType()));
408 } else if (Depth == 6) { // Limit search depth.
412 APInt KnownZero2, KnownOne2, KnownZeroOut, KnownOneOut;
413 switch (Op.getOpcode()) {
415 // We know all of the bits for a constant!
416 KnownOne = cast<ConstantSDNode>(Op)->getAPIntValue();
417 KnownZero = ~KnownOne;
418 return false; // Don't fall through, will infinitely loop.
420 // If the RHS is a constant, check to see if the LHS would be zero without
421 // using the bits from the RHS. Below, we use knowledge about the RHS to
422 // simplify the LHS, here we're using information from the LHS to simplify
424 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
425 APInt LHSZero, LHSOne;
426 // Do not increment Depth here; that can cause an infinite loop.
427 TLO.DAG.computeKnownBits(Op.getOperand(0), LHSZero, LHSOne, Depth);
428 // If the LHS already has zeros where RHSC does, this and is dead.
429 if ((LHSZero & NewMask) == (~RHSC->getAPIntValue() & NewMask))
430 return TLO.CombineTo(Op, Op.getOperand(0));
431 // If any of the set bits in the RHS are known zero on the LHS, shrink
433 if (TLO.ShrinkDemandedConstant(Op, ~LHSZero & NewMask))
437 if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
438 KnownOne, TLO, Depth+1))
440 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
441 if (SimplifyDemandedBits(Op.getOperand(0), ~KnownZero & NewMask,
442 KnownZero2, KnownOne2, TLO, Depth+1))
444 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
446 // If all of the demanded bits are known one on one side, return the other.
447 // These bits cannot contribute to the result of the 'and'.
448 if ((NewMask & ~KnownZero2 & KnownOne) == (~KnownZero2 & NewMask))
449 return TLO.CombineTo(Op, Op.getOperand(0));
450 if ((NewMask & ~KnownZero & KnownOne2) == (~KnownZero & NewMask))
451 return TLO.CombineTo(Op, Op.getOperand(1));
452 // If all of the demanded bits in the inputs are known zeros, return zero.
453 if ((NewMask & (KnownZero|KnownZero2)) == NewMask)
454 return TLO.CombineTo(Op, TLO.DAG.getConstant(0, dl, Op.getValueType()));
455 // If the RHS is a constant, see if we can simplify it.
456 if (TLO.ShrinkDemandedConstant(Op, ~KnownZero2 & NewMask))
458 // If the operation can be done in a smaller type, do so.
459 if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
462 // Output known-1 bits are only known if set in both the LHS & RHS.
463 KnownOne &= KnownOne2;
464 // Output known-0 are known to be clear if zero in either the LHS | RHS.
465 KnownZero |= KnownZero2;
468 if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
469 KnownOne, TLO, Depth+1))
471 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
472 if (SimplifyDemandedBits(Op.getOperand(0), ~KnownOne & NewMask,
473 KnownZero2, KnownOne2, TLO, Depth+1))
475 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
477 // If all of the demanded bits are known zero on one side, return the other.
478 // These bits cannot contribute to the result of the 'or'.
479 if ((NewMask & ~KnownOne2 & KnownZero) == (~KnownOne2 & NewMask))
480 return TLO.CombineTo(Op, Op.getOperand(0));
481 if ((NewMask & ~KnownOne & KnownZero2) == (~KnownOne & NewMask))
482 return TLO.CombineTo(Op, Op.getOperand(1));
483 // If all of the potentially set bits on one side are known to be set on
484 // the other side, just use the 'other' side.
485 if ((NewMask & ~KnownZero & KnownOne2) == (~KnownZero & NewMask))
486 return TLO.CombineTo(Op, Op.getOperand(0));
487 if ((NewMask & ~KnownZero2 & KnownOne) == (~KnownZero2 & NewMask))
488 return TLO.CombineTo(Op, Op.getOperand(1));
489 // If the RHS is a constant, see if we can simplify it.
490 if (TLO.ShrinkDemandedConstant(Op, NewMask))
492 // If the operation can be done in a smaller type, do so.
493 if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
496 // Output known-0 bits are only known if clear in both the LHS & RHS.
497 KnownZero &= KnownZero2;
498 // Output known-1 are known to be set if set in either the LHS | RHS.
499 KnownOne |= KnownOne2;
502 if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
503 KnownOne, TLO, Depth+1))
505 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
506 if (SimplifyDemandedBits(Op.getOperand(0), NewMask, KnownZero2,
507 KnownOne2, TLO, Depth+1))
509 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
511 // If all of the demanded bits are known zero on one side, return the other.
512 // These bits cannot contribute to the result of the 'xor'.
513 if ((KnownZero & NewMask) == NewMask)
514 return TLO.CombineTo(Op, Op.getOperand(0));
515 if ((KnownZero2 & NewMask) == NewMask)
516 return TLO.CombineTo(Op, Op.getOperand(1));
517 // If the operation can be done in a smaller type, do so.
518 if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
521 // If all of the unknown bits are known to be zero on one side or the other
522 // (but not both) turn this into an *inclusive* or.
523 // e.g. (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1&C2 == 0
524 if ((NewMask & ~KnownZero & ~KnownZero2) == 0)
525 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::OR, dl, Op.getValueType(),
529 // Output known-0 bits are known if clear or set in both the LHS & RHS.
530 KnownZeroOut = (KnownZero & KnownZero2) | (KnownOne & KnownOne2);
531 // Output known-1 are known to be set if set in only one of the LHS, RHS.
532 KnownOneOut = (KnownZero & KnownOne2) | (KnownOne & KnownZero2);
534 // If all of the demanded bits on one side are known, and all of the set
535 // bits on that side are also known to be set on the other side, turn this
536 // into an AND, as we know the bits will be cleared.
537 // e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2
538 // NB: it is okay if more bits are known than are requested
539 if ((NewMask & (KnownZero|KnownOne)) == NewMask) { // all known on one side
540 if (KnownOne == KnownOne2) { // set bits are the same on both sides
541 EVT VT = Op.getValueType();
542 SDValue ANDC = TLO.DAG.getConstant(~KnownOne & NewMask, dl, VT);
543 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::AND, dl, VT,
544 Op.getOperand(0), ANDC));
548 // If the RHS is a constant, see if we can simplify it.
549 // for XOR, we prefer to force bits to 1 if they will make a -1.
550 // if we can't force bits, try to shrink constant
551 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
552 APInt Expanded = C->getAPIntValue() | (~NewMask);
553 // if we can expand it to have all bits set, do it
554 if (Expanded.isAllOnesValue()) {
555 if (Expanded != C->getAPIntValue()) {
556 EVT VT = Op.getValueType();
557 SDValue New = TLO.DAG.getNode(Op.getOpcode(), dl,VT, Op.getOperand(0),
558 TLO.DAG.getConstant(Expanded, dl, VT));
559 return TLO.CombineTo(Op, New);
561 // if it already has all the bits set, nothing to change
562 // but don't shrink either!
563 } else if (TLO.ShrinkDemandedConstant(Op, NewMask)) {
568 KnownZero = KnownZeroOut;
569 KnownOne = KnownOneOut;
572 if (SimplifyDemandedBits(Op.getOperand(2), NewMask, KnownZero,
573 KnownOne, TLO, Depth+1))
575 if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero2,
576 KnownOne2, TLO, Depth+1))
578 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
579 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
581 // If the operands are constants, see if we can simplify them.
582 if (TLO.ShrinkDemandedConstant(Op, NewMask))
585 // Only known if known in both the LHS and RHS.
586 KnownOne &= KnownOne2;
587 KnownZero &= KnownZero2;
590 if (SimplifyDemandedBits(Op.getOperand(3), NewMask, KnownZero,
591 KnownOne, TLO, Depth+1))
593 if (SimplifyDemandedBits(Op.getOperand(2), NewMask, KnownZero2,
594 KnownOne2, TLO, Depth+1))
596 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
597 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
599 // If the operands are constants, see if we can simplify them.
600 if (TLO.ShrinkDemandedConstant(Op, NewMask))
603 // Only known if known in both the LHS and RHS.
604 KnownOne &= KnownOne2;
605 KnownZero &= KnownZero2;
608 if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
609 unsigned ShAmt = SA->getZExtValue();
610 SDValue InOp = Op.getOperand(0);
612 // If the shift count is an invalid immediate, don't do anything.
613 if (ShAmt >= BitWidth)
616 // If this is ((X >>u C1) << ShAmt), see if we can simplify this into a
617 // single shift. We can do this if the bottom bits (which are shifted
618 // out) are never demanded.
619 if (InOp.getOpcode() == ISD::SRL &&
620 isa<ConstantSDNode>(InOp.getOperand(1))) {
621 if (ShAmt && (NewMask & APInt::getLowBitsSet(BitWidth, ShAmt)) == 0) {
622 unsigned C1= cast<ConstantSDNode>(InOp.getOperand(1))->getZExtValue();
623 unsigned Opc = ISD::SHL;
631 TLO.DAG.getConstant(Diff, dl, Op.getOperand(1).getValueType());
632 EVT VT = Op.getValueType();
633 return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT,
634 InOp.getOperand(0), NewSA));
638 if (SimplifyDemandedBits(InOp, NewMask.lshr(ShAmt),
639 KnownZero, KnownOne, TLO, Depth+1))
642 // Convert (shl (anyext x, c)) to (anyext (shl x, c)) if the high bits
643 // are not demanded. This will likely allow the anyext to be folded away.
644 if (InOp.getNode()->getOpcode() == ISD::ANY_EXTEND) {
645 SDValue InnerOp = InOp.getNode()->getOperand(0);
646 EVT InnerVT = InnerOp.getValueType();
647 unsigned InnerBits = InnerVT.getSizeInBits();
648 if (ShAmt < InnerBits && NewMask.lshr(InnerBits) == 0 &&
649 isTypeDesirableForOp(ISD::SHL, InnerVT)) {
650 EVT ShTy = getShiftAmountTy(InnerVT, DL);
651 if (!APInt(BitWidth, ShAmt).isIntN(ShTy.getSizeInBits()))
654 TLO.DAG.getNode(ISD::SHL, dl, InnerVT, InnerOp,
655 TLO.DAG.getConstant(ShAmt, dl, ShTy));
658 TLO.DAG.getNode(ISD::ANY_EXTEND, dl, Op.getValueType(),
661 // Repeat the SHL optimization above in cases where an extension
662 // intervenes: (shl (anyext (shr x, c1)), c2) to
663 // (shl (anyext x), c2-c1). This requires that the bottom c1 bits
664 // aren't demanded (as above) and that the shifted upper c1 bits of
665 // x aren't demanded.
666 if (InOp.hasOneUse() &&
667 InnerOp.getOpcode() == ISD::SRL &&
668 InnerOp.hasOneUse() &&
669 isa<ConstantSDNode>(InnerOp.getOperand(1))) {
670 uint64_t InnerShAmt = cast<ConstantSDNode>(InnerOp.getOperand(1))
672 if (InnerShAmt < ShAmt &&
673 InnerShAmt < InnerBits &&
674 NewMask.lshr(InnerBits - InnerShAmt + ShAmt) == 0 &&
675 NewMask.trunc(ShAmt) == 0) {
677 TLO.DAG.getConstant(ShAmt - InnerShAmt, dl,
678 Op.getOperand(1).getValueType());
679 EVT VT = Op.getValueType();
680 SDValue NewExt = TLO.DAG.getNode(ISD::ANY_EXTEND, dl, VT,
681 InnerOp.getOperand(0));
682 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl, VT,
688 KnownZero <<= SA->getZExtValue();
689 KnownOne <<= SA->getZExtValue();
690 // low bits known zero.
691 KnownZero |= APInt::getLowBitsSet(BitWidth, SA->getZExtValue());
695 if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
696 EVT VT = Op.getValueType();
697 unsigned ShAmt = SA->getZExtValue();
698 unsigned VTSize = VT.getSizeInBits();
699 SDValue InOp = Op.getOperand(0);
701 // If the shift count is an invalid immediate, don't do anything.
702 if (ShAmt >= BitWidth)
705 APInt InDemandedMask = (NewMask << ShAmt);
707 // If the shift is exact, then it does demand the low bits (and knows that
709 if (cast<BinaryWithFlagsSDNode>(Op)->Flags.hasExact())
710 InDemandedMask |= APInt::getLowBitsSet(BitWidth, ShAmt);
712 // If this is ((X << C1) >>u ShAmt), see if we can simplify this into a
713 // single shift. We can do this if the top bits (which are shifted out)
714 // are never demanded.
715 if (InOp.getOpcode() == ISD::SHL &&
716 isa<ConstantSDNode>(InOp.getOperand(1))) {
717 if (ShAmt && (NewMask & APInt::getHighBitsSet(VTSize, ShAmt)) == 0) {
718 unsigned C1= cast<ConstantSDNode>(InOp.getOperand(1))->getZExtValue();
719 unsigned Opc = ISD::SRL;
727 TLO.DAG.getConstant(Diff, dl, Op.getOperand(1).getValueType());
728 return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT,
729 InOp.getOperand(0), NewSA));
733 // Compute the new bits that are at the top now.
734 if (SimplifyDemandedBits(InOp, InDemandedMask,
735 KnownZero, KnownOne, TLO, Depth+1))
737 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
738 KnownZero = KnownZero.lshr(ShAmt);
739 KnownOne = KnownOne.lshr(ShAmt);
741 APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
742 KnownZero |= HighBits; // High bits known zero.
746 // If this is an arithmetic shift right and only the low-bit is set, we can
747 // always convert this into a logical shr, even if the shift amount is
748 // variable. The low bit of the shift cannot be an input sign bit unless
749 // the shift amount is >= the size of the datatype, which is undefined.
751 return TLO.CombineTo(Op,
752 TLO.DAG.getNode(ISD::SRL, dl, Op.getValueType(),
753 Op.getOperand(0), Op.getOperand(1)));
755 if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
756 EVT VT = Op.getValueType();
757 unsigned ShAmt = SA->getZExtValue();
759 // If the shift count is an invalid immediate, don't do anything.
760 if (ShAmt >= BitWidth)
763 APInt InDemandedMask = (NewMask << ShAmt);
765 // If the shift is exact, then it does demand the low bits (and knows that
767 if (cast<BinaryWithFlagsSDNode>(Op)->Flags.hasExact())
768 InDemandedMask |= APInt::getLowBitsSet(BitWidth, ShAmt);
770 // If any of the demanded bits are produced by the sign extension, we also
771 // demand the input sign bit.
772 APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
773 if (HighBits.intersects(NewMask))
774 InDemandedMask |= APInt::getSignBit(VT.getScalarType().getSizeInBits());
776 if (SimplifyDemandedBits(Op.getOperand(0), InDemandedMask,
777 KnownZero, KnownOne, TLO, Depth+1))
779 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
780 KnownZero = KnownZero.lshr(ShAmt);
781 KnownOne = KnownOne.lshr(ShAmt);
783 // Handle the sign bit, adjusted to where it is now in the mask.
784 APInt SignBit = APInt::getSignBit(BitWidth).lshr(ShAmt);
786 // If the input sign bit is known to be zero, or if none of the top bits
787 // are demanded, turn this into an unsigned shift right.
788 if (KnownZero.intersects(SignBit) || (HighBits & ~NewMask) == HighBits) {
790 Flags.setExact(cast<BinaryWithFlagsSDNode>(Op)->Flags.hasExact());
791 return TLO.CombineTo(Op,
792 TLO.DAG.getNode(ISD::SRL, dl, VT, Op.getOperand(0),
793 Op.getOperand(1), &Flags));
796 int Log2 = NewMask.exactLogBase2();
798 // The bit must come from the sign.
800 TLO.DAG.getConstant(BitWidth - 1 - Log2, dl,
801 Op.getOperand(1).getValueType());
802 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl, VT,
803 Op.getOperand(0), NewSA));
806 if (KnownOne.intersects(SignBit))
807 // New bits are known one.
808 KnownOne |= HighBits;
811 case ISD::SIGN_EXTEND_INREG: {
812 EVT ExVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
814 APInt MsbMask = APInt::getHighBitsSet(BitWidth, 1);
815 // If we only care about the highest bit, don't bother shifting right.
816 if (MsbMask == NewMask) {
817 unsigned ShAmt = ExVT.getScalarType().getSizeInBits();
818 SDValue InOp = Op.getOperand(0);
819 unsigned VTBits = Op->getValueType(0).getScalarType().getSizeInBits();
820 bool AlreadySignExtended =
821 TLO.DAG.ComputeNumSignBits(InOp) >= VTBits-ShAmt+1;
822 // However if the input is already sign extended we expect the sign
823 // extension to be dropped altogether later and do not simplify.
824 if (!AlreadySignExtended) {
825 // Compute the correct shift amount type, which must be getShiftAmountTy
826 // for scalar types after legalization.
827 EVT ShiftAmtTy = Op.getValueType();
828 if (TLO.LegalTypes() && !ShiftAmtTy.isVector())
829 ShiftAmtTy = getShiftAmountTy(ShiftAmtTy, DL);
831 SDValue ShiftAmt = TLO.DAG.getConstant(BitWidth - ShAmt, dl,
833 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl,
834 Op.getValueType(), InOp,
839 // Sign extension. Compute the demanded bits in the result that are not
840 // present in the input.
842 APInt::getHighBitsSet(BitWidth,
843 BitWidth - ExVT.getScalarType().getSizeInBits());
845 // If none of the extended bits are demanded, eliminate the sextinreg.
846 if ((NewBits & NewMask) == 0)
847 return TLO.CombineTo(Op, Op.getOperand(0));
850 APInt::getSignBit(ExVT.getScalarType().getSizeInBits()).zext(BitWidth);
851 APInt InputDemandedBits =
852 APInt::getLowBitsSet(BitWidth,
853 ExVT.getScalarType().getSizeInBits()) &
856 // Since the sign extended bits are demanded, we know that the sign
858 InputDemandedBits |= InSignBit;
860 if (SimplifyDemandedBits(Op.getOperand(0), InputDemandedBits,
861 KnownZero, KnownOne, TLO, Depth+1))
863 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
865 // If the sign bit of the input is known set or clear, then we know the
866 // top bits of the result.
868 // If the input sign bit is known zero, convert this into a zero extension.
869 if (KnownZero.intersects(InSignBit))
870 return TLO.CombineTo(Op,
871 TLO.DAG.getZeroExtendInReg(Op.getOperand(0),dl,ExVT));
873 if (KnownOne.intersects(InSignBit)) { // Input sign bit known set
875 KnownZero &= ~NewBits;
876 } else { // Input sign bit unknown
877 KnownZero &= ~NewBits;
878 KnownOne &= ~NewBits;
882 case ISD::BUILD_PAIR: {
883 EVT HalfVT = Op.getOperand(0).getValueType();
884 unsigned HalfBitWidth = HalfVT.getScalarSizeInBits();
886 APInt MaskLo = NewMask.getLoBits(HalfBitWidth).trunc(HalfBitWidth);
887 APInt MaskHi = NewMask.getHiBits(HalfBitWidth).trunc(HalfBitWidth);
889 APInt KnownZeroLo, KnownOneLo;
890 APInt KnownZeroHi, KnownOneHi;
892 if (SimplifyDemandedBits(Op.getOperand(0), MaskLo, KnownZeroLo,
893 KnownOneLo, TLO, Depth + 1))
896 if (SimplifyDemandedBits(Op.getOperand(1), MaskHi, KnownZeroHi,
897 KnownOneHi, TLO, Depth + 1))
900 KnownZero = KnownZeroLo.zext(BitWidth) |
901 KnownZeroHi.zext(BitWidth).shl(HalfBitWidth);
903 KnownOne = KnownOneLo.zext(BitWidth) |
904 KnownOneHi.zext(BitWidth).shl(HalfBitWidth);
907 case ISD::ZERO_EXTEND: {
908 unsigned OperandBitWidth =
909 Op.getOperand(0).getValueType().getScalarType().getSizeInBits();
910 APInt InMask = NewMask.trunc(OperandBitWidth);
912 // If none of the top bits are demanded, convert this into an any_extend.
914 APInt::getHighBitsSet(BitWidth, BitWidth - OperandBitWidth) & NewMask;
915 if (!NewBits.intersects(NewMask))
916 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ANY_EXTEND, dl,
920 if (SimplifyDemandedBits(Op.getOperand(0), InMask,
921 KnownZero, KnownOne, TLO, Depth+1))
923 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
924 KnownZero = KnownZero.zext(BitWidth);
925 KnownOne = KnownOne.zext(BitWidth);
926 KnownZero |= NewBits;
929 case ISD::SIGN_EXTEND: {
930 EVT InVT = Op.getOperand(0).getValueType();
931 unsigned InBits = InVT.getScalarType().getSizeInBits();
932 APInt InMask = APInt::getLowBitsSet(BitWidth, InBits);
933 APInt InSignBit = APInt::getBitsSet(BitWidth, InBits - 1, InBits);
934 APInt NewBits = ~InMask & NewMask;
936 // If none of the top bits are demanded, convert this into an any_extend.
938 return TLO.CombineTo(Op,TLO.DAG.getNode(ISD::ANY_EXTEND, dl,
942 // Since some of the sign extended bits are demanded, we know that the sign
944 APInt InDemandedBits = InMask & NewMask;
945 InDemandedBits |= InSignBit;
946 InDemandedBits = InDemandedBits.trunc(InBits);
948 if (SimplifyDemandedBits(Op.getOperand(0), InDemandedBits, KnownZero,
949 KnownOne, TLO, Depth+1))
951 KnownZero = KnownZero.zext(BitWidth);
952 KnownOne = KnownOne.zext(BitWidth);
954 // If the sign bit is known zero, convert this to a zero extend.
955 if (KnownZero.intersects(InSignBit))
956 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ZERO_EXTEND, dl,
960 // If the sign bit is known one, the top bits match.
961 if (KnownOne.intersects(InSignBit)) {
963 assert((KnownZero & NewBits) == 0);
964 } else { // Otherwise, top bits aren't known.
965 assert((KnownOne & NewBits) == 0);
966 assert((KnownZero & NewBits) == 0);
970 case ISD::ANY_EXTEND: {
971 unsigned OperandBitWidth =
972 Op.getOperand(0).getValueType().getScalarType().getSizeInBits();
973 APInt InMask = NewMask.trunc(OperandBitWidth);
974 if (SimplifyDemandedBits(Op.getOperand(0), InMask,
975 KnownZero, KnownOne, TLO, Depth+1))
977 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
978 KnownZero = KnownZero.zext(BitWidth);
979 KnownOne = KnownOne.zext(BitWidth);
982 case ISD::TRUNCATE: {
983 // Simplify the input, using demanded bit information, and compute the known
984 // zero/one bits live out.
985 unsigned OperandBitWidth =
986 Op.getOperand(0).getValueType().getScalarType().getSizeInBits();
987 APInt TruncMask = NewMask.zext(OperandBitWidth);
988 if (SimplifyDemandedBits(Op.getOperand(0), TruncMask,
989 KnownZero, KnownOne, TLO, Depth+1))
991 KnownZero = KnownZero.trunc(BitWidth);
992 KnownOne = KnownOne.trunc(BitWidth);
994 // If the input is only used by this truncate, see if we can shrink it based
995 // on the known demanded bits.
996 if (Op.getOperand(0).getNode()->hasOneUse()) {
997 SDValue In = Op.getOperand(0);
998 switch (In.getOpcode()) {
1001 // Shrink SRL by a constant if none of the high bits shifted in are
1003 if (TLO.LegalTypes() &&
1004 !isTypeDesirableForOp(ISD::SRL, Op.getValueType()))
1005 // Do not turn (vt1 truncate (vt2 srl)) into (vt1 srl) if vt1 is
1008 ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(In.getOperand(1));
1011 SDValue Shift = In.getOperand(1);
1012 if (TLO.LegalTypes()) {
1013 uint64_t ShVal = ShAmt->getZExtValue();
1014 Shift = TLO.DAG.getConstant(ShVal, dl,
1015 getShiftAmountTy(Op.getValueType(), DL));
1018 APInt HighBits = APInt::getHighBitsSet(OperandBitWidth,
1019 OperandBitWidth - BitWidth);
1020 HighBits = HighBits.lshr(ShAmt->getZExtValue()).trunc(BitWidth);
1022 if (ShAmt->getZExtValue() < BitWidth && !(HighBits & NewMask)) {
1023 // None of the shifted in bits are needed. Add a truncate of the
1024 // shift input, then shift it.
1025 SDValue NewTrunc = TLO.DAG.getNode(ISD::TRUNCATE, dl,
1028 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl,
1037 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
1040 case ISD::AssertZext: {
1041 // AssertZext demands all of the high bits, plus any of the low bits
1042 // demanded by its users.
1043 EVT VT = cast<VTSDNode>(Op.getOperand(1))->getVT();
1044 APInt InMask = APInt::getLowBitsSet(BitWidth,
1045 VT.getSizeInBits());
1046 if (SimplifyDemandedBits(Op.getOperand(0), ~InMask | NewMask,
1047 KnownZero, KnownOne, TLO, Depth+1))
1049 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
1051 KnownZero |= ~InMask & NewMask;
1055 // If this is an FP->Int bitcast and if the sign bit is the only
1056 // thing demanded, turn this into a FGETSIGN.
1057 if (!TLO.LegalOperations() &&
1058 !Op.getValueType().isVector() &&
1059 !Op.getOperand(0).getValueType().isVector() &&
1060 NewMask == APInt::getSignBit(Op.getValueType().getSizeInBits()) &&
1061 Op.getOperand(0).getValueType().isFloatingPoint()) {
1062 bool OpVTLegal = isOperationLegalOrCustom(ISD::FGETSIGN, Op.getValueType());
1063 bool i32Legal = isOperationLegalOrCustom(ISD::FGETSIGN, MVT::i32);
1064 if ((OpVTLegal || i32Legal) && Op.getValueType().isSimple()) {
1065 EVT Ty = OpVTLegal ? Op.getValueType() : MVT::i32;
1066 // Make a FGETSIGN + SHL to move the sign bit into the appropriate
1067 // place. We expect the SHL to be eliminated by other optimizations.
1068 SDValue Sign = TLO.DAG.getNode(ISD::FGETSIGN, dl, Ty, Op.getOperand(0));
1069 unsigned OpVTSizeInBits = Op.getValueType().getSizeInBits();
1070 if (!OpVTLegal && OpVTSizeInBits > 32)
1071 Sign = TLO.DAG.getNode(ISD::ZERO_EXTEND, dl, Op.getValueType(), Sign);
1072 unsigned ShVal = Op.getValueType().getSizeInBits()-1;
1073 SDValue ShAmt = TLO.DAG.getConstant(ShVal, dl, Op.getValueType());
1074 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl,
1083 // Add, Sub, and Mul don't demand any bits in positions beyond that
1084 // of the highest bit demanded of them.
1085 APInt LoMask = APInt::getLowBitsSet(BitWidth,
1086 BitWidth - NewMask.countLeadingZeros());
1087 if (SimplifyDemandedBits(Op.getOperand(0), LoMask, KnownZero2,
1088 KnownOne2, TLO, Depth+1))
1090 if (SimplifyDemandedBits(Op.getOperand(1), LoMask, KnownZero2,
1091 KnownOne2, TLO, Depth+1))
1093 // See if the operation should be performed at a smaller bit width.
1094 if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
1099 // Just use computeKnownBits to compute output bits.
1100 TLO.DAG.computeKnownBits(Op, KnownZero, KnownOne, Depth);
1104 // If we know the value of all of the demanded bits, return this as a
1106 if ((NewMask & (KnownZero|KnownOne)) == NewMask) {
1107 // Avoid folding to a constant if any OpaqueConstant is involved.
1108 const SDNode *N = Op.getNode();
1109 for (SDNodeIterator I = SDNodeIterator::begin(N),
1110 E = SDNodeIterator::end(N); I != E; ++I) {
1112 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op))
1116 return TLO.CombineTo(Op,
1117 TLO.DAG.getConstant(KnownOne, dl, Op.getValueType()));
1123 /// computeKnownBitsForTargetNode - Determine which of the bits specified
1124 /// in Mask are known to be either zero or one and return them in the
1125 /// KnownZero/KnownOne bitsets.
1126 void TargetLowering::computeKnownBitsForTargetNode(const SDValue Op,
1129 const SelectionDAG &DAG,
1130 unsigned Depth) const {
1131 assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
1132 Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
1133 Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
1134 Op.getOpcode() == ISD::INTRINSIC_VOID) &&
1135 "Should use MaskedValueIsZero if you don't know whether Op"
1136 " is a target node!");
1137 KnownZero = KnownOne = APInt(KnownOne.getBitWidth(), 0);
1140 /// ComputeNumSignBitsForTargetNode - This method can be implemented by
1141 /// targets that want to expose additional information about sign bits to the
1143 unsigned TargetLowering::ComputeNumSignBitsForTargetNode(SDValue Op,
1144 const SelectionDAG &,
1145 unsigned Depth) const {
1146 assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
1147 Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
1148 Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
1149 Op.getOpcode() == ISD::INTRINSIC_VOID) &&
1150 "Should use ComputeNumSignBits if you don't know whether Op"
1151 " is a target node!");
1155 /// ValueHasExactlyOneBitSet - Test if the given value is known to have exactly
1156 /// one bit set. This differs from computeKnownBits in that it doesn't need to
1157 /// determine which bit is set.
1159 static bool ValueHasExactlyOneBitSet(SDValue Val, const SelectionDAG &DAG) {
1160 // A left-shift of a constant one will have exactly one bit set, because
1161 // shifting the bit off the end is undefined.
1162 if (Val.getOpcode() == ISD::SHL)
1163 if (ConstantSDNode *C =
1164 dyn_cast<ConstantSDNode>(Val.getNode()->getOperand(0)))
1165 if (C->getAPIntValue() == 1)
1168 // Similarly, a right-shift of a constant sign-bit will have exactly
1170 if (Val.getOpcode() == ISD::SRL)
1171 if (ConstantSDNode *C =
1172 dyn_cast<ConstantSDNode>(Val.getNode()->getOperand(0)))
1173 if (C->getAPIntValue().isSignBit())
1176 // More could be done here, though the above checks are enough
1177 // to handle some common cases.
1179 // Fall back to computeKnownBits to catch other known cases.
1180 EVT OpVT = Val.getValueType();
1181 unsigned BitWidth = OpVT.getScalarType().getSizeInBits();
1182 APInt KnownZero, KnownOne;
1183 DAG.computeKnownBits(Val, KnownZero, KnownOne);
1184 return (KnownZero.countPopulation() == BitWidth - 1) &&
1185 (KnownOne.countPopulation() == 1);
1188 bool TargetLowering::isConstTrueVal(const SDNode *N) const {
1192 const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N);
1194 const BuildVectorSDNode *BV = dyn_cast<BuildVectorSDNode>(N);
1198 BitVector UndefElements;
1199 CN = BV->getConstantSplatNode(&UndefElements);
1200 // Only interested in constant splats, and we don't try to handle undef
1201 // elements in identifying boolean constants.
1202 if (!CN || UndefElements.none())
1206 switch (getBooleanContents(N->getValueType(0))) {
1207 case UndefinedBooleanContent:
1208 return CN->getAPIntValue()[0];
1209 case ZeroOrOneBooleanContent:
1211 case ZeroOrNegativeOneBooleanContent:
1212 return CN->isAllOnesValue();
1215 llvm_unreachable("Invalid boolean contents");
1218 bool TargetLowering::isConstFalseVal(const SDNode *N) const {
1222 const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N);
1224 const BuildVectorSDNode *BV = dyn_cast<BuildVectorSDNode>(N);
1228 BitVector UndefElements;
1229 CN = BV->getConstantSplatNode(&UndefElements);
1230 // Only interested in constant splats, and we don't try to handle undef
1231 // elements in identifying boolean constants.
1232 if (!CN || UndefElements.none())
1236 if (getBooleanContents(N->getValueType(0)) == UndefinedBooleanContent)
1237 return !CN->getAPIntValue()[0];
1239 return CN->isNullValue();
1242 /// SimplifySetCC - Try to simplify a setcc built with the specified operands
1243 /// and cc. If it is unable to simplify it, return a null SDValue.
1245 TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
1246 ISD::CondCode Cond, bool foldBooleans,
1247 DAGCombinerInfo &DCI, SDLoc dl) const {
1248 SelectionDAG &DAG = DCI.DAG;
1250 // These setcc operations always fold.
1254 case ISD::SETFALSE2: return DAG.getConstant(0, dl, VT);
1256 case ISD::SETTRUE2: {
1257 TargetLowering::BooleanContent Cnt =
1258 getBooleanContents(N0->getValueType(0));
1259 return DAG.getConstant(
1260 Cnt == TargetLowering::ZeroOrNegativeOneBooleanContent ? -1ULL : 1, dl,
1265 // Ensure that the constant occurs on the RHS, and fold constant
1267 ISD::CondCode SwappedCC = ISD::getSetCCSwappedOperands(Cond);
1268 if (isa<ConstantSDNode>(N0.getNode()) &&
1269 (DCI.isBeforeLegalizeOps() ||
1270 isCondCodeLegal(SwappedCC, N0.getSimpleValueType())))
1271 return DAG.getSetCC(dl, VT, N1, N0, SwappedCC);
1273 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode())) {
1274 const APInt &C1 = N1C->getAPIntValue();
1276 // If the LHS is '(srl (ctlz x), 5)', the RHS is 0/1, and this is an
1277 // equality comparison, then we're just comparing whether X itself is
1279 if (N0.getOpcode() == ISD::SRL && (C1 == 0 || C1 == 1) &&
1280 N0.getOperand(0).getOpcode() == ISD::CTLZ &&
1281 N0.getOperand(1).getOpcode() == ISD::Constant) {
1283 = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
1284 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1285 ShAmt == Log2_32(N0.getValueType().getSizeInBits())) {
1286 if ((C1 == 0) == (Cond == ISD::SETEQ)) {
1287 // (srl (ctlz x), 5) == 0 -> X != 0
1288 // (srl (ctlz x), 5) != 1 -> X != 0
1291 // (srl (ctlz x), 5) != 0 -> X == 0
1292 // (srl (ctlz x), 5) == 1 -> X == 0
1295 SDValue Zero = DAG.getConstant(0, dl, N0.getValueType());
1296 return DAG.getSetCC(dl, VT, N0.getOperand(0).getOperand(0),
1302 // Look through truncs that don't change the value of a ctpop.
1303 if (N0.hasOneUse() && N0.getOpcode() == ISD::TRUNCATE)
1304 CTPOP = N0.getOperand(0);
1306 if (CTPOP.hasOneUse() && CTPOP.getOpcode() == ISD::CTPOP &&
1307 (N0 == CTPOP || N0.getValueType().getSizeInBits() >
1308 Log2_32_Ceil(CTPOP.getValueType().getSizeInBits()))) {
1309 EVT CTVT = CTPOP.getValueType();
1310 SDValue CTOp = CTPOP.getOperand(0);
1312 // (ctpop x) u< 2 -> (x & x-1) == 0
1313 // (ctpop x) u> 1 -> (x & x-1) != 0
1314 if ((Cond == ISD::SETULT && C1 == 2) || (Cond == ISD::SETUGT && C1 == 1)){
1315 SDValue Sub = DAG.getNode(ISD::SUB, dl, CTVT, CTOp,
1316 DAG.getConstant(1, dl, CTVT));
1317 SDValue And = DAG.getNode(ISD::AND, dl, CTVT, CTOp, Sub);
1318 ISD::CondCode CC = Cond == ISD::SETULT ? ISD::SETEQ : ISD::SETNE;
1319 return DAG.getSetCC(dl, VT, And, DAG.getConstant(0, dl, CTVT), CC);
1322 // TODO: (ctpop x) == 1 -> x && (x & x-1) == 0 iff ctpop is illegal.
1325 // (zext x) == C --> x == (trunc C)
1326 // (sext x) == C --> x == (trunc C)
1327 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1328 DCI.isBeforeLegalize() && N0->hasOneUse()) {
1329 unsigned MinBits = N0.getValueSizeInBits();
1331 bool Signed = false;
1332 if (N0->getOpcode() == ISD::ZERO_EXTEND) {
1334 MinBits = N0->getOperand(0).getValueSizeInBits();
1335 PreExt = N0->getOperand(0);
1336 } else if (N0->getOpcode() == ISD::AND) {
1337 // DAGCombine turns costly ZExts into ANDs
1338 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0->getOperand(1)))
1339 if ((C->getAPIntValue()+1).isPowerOf2()) {
1340 MinBits = C->getAPIntValue().countTrailingOnes();
1341 PreExt = N0->getOperand(0);
1343 } else if (N0->getOpcode() == ISD::SIGN_EXTEND) {
1345 MinBits = N0->getOperand(0).getValueSizeInBits();
1346 PreExt = N0->getOperand(0);
1348 } else if (LoadSDNode *LN0 = dyn_cast<LoadSDNode>(N0)) {
1349 // ZEXTLOAD / SEXTLOAD
1350 if (LN0->getExtensionType() == ISD::ZEXTLOAD) {
1351 MinBits = LN0->getMemoryVT().getSizeInBits();
1353 } else if (LN0->getExtensionType() == ISD::SEXTLOAD) {
1355 MinBits = LN0->getMemoryVT().getSizeInBits();
1360 // Figure out how many bits we need to preserve this constant.
1361 unsigned ReqdBits = Signed ?
1362 C1.getBitWidth() - C1.getNumSignBits() + 1 :
1365 // Make sure we're not losing bits from the constant.
1367 MinBits < C1.getBitWidth() &&
1368 MinBits >= ReqdBits) {
1369 EVT MinVT = EVT::getIntegerVT(*DAG.getContext(), MinBits);
1370 if (isTypeDesirableForOp(ISD::SETCC, MinVT)) {
1371 // Will get folded away.
1372 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, MinVT, PreExt);
1373 SDValue C = DAG.getConstant(C1.trunc(MinBits), dl, MinVT);
1374 return DAG.getSetCC(dl, VT, Trunc, C, Cond);
1379 // If the LHS is '(and load, const)', the RHS is 0,
1380 // the test is for equality or unsigned, and all 1 bits of the const are
1381 // in the same partial word, see if we can shorten the load.
1382 if (DCI.isBeforeLegalize() &&
1383 !ISD::isSignedIntSetCC(Cond) &&
1384 N0.getOpcode() == ISD::AND && C1 == 0 &&
1385 N0.getNode()->hasOneUse() &&
1386 isa<LoadSDNode>(N0.getOperand(0)) &&
1387 N0.getOperand(0).getNode()->hasOneUse() &&
1388 isa<ConstantSDNode>(N0.getOperand(1))) {
1389 LoadSDNode *Lod = cast<LoadSDNode>(N0.getOperand(0));
1391 unsigned bestWidth = 0, bestOffset = 0;
1392 if (!Lod->isVolatile() && Lod->isUnindexed()) {
1393 unsigned origWidth = N0.getValueType().getSizeInBits();
1394 unsigned maskWidth = origWidth;
1395 // We can narrow (e.g.) 16-bit extending loads on 32-bit target to
1396 // 8 bits, but have to be careful...
1397 if (Lod->getExtensionType() != ISD::NON_EXTLOAD)
1398 origWidth = Lod->getMemoryVT().getSizeInBits();
1400 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
1401 for (unsigned width = origWidth / 2; width>=8; width /= 2) {
1402 APInt newMask = APInt::getLowBitsSet(maskWidth, width);
1403 for (unsigned offset=0; offset<origWidth/width; offset++) {
1404 if ((newMask & Mask) == Mask) {
1405 if (!DAG.getDataLayout().isLittleEndian())
1406 bestOffset = (origWidth/width - offset - 1) * (width/8);
1408 bestOffset = (uint64_t)offset * (width/8);
1409 bestMask = Mask.lshr(offset * (width/8) * 8);
1413 newMask = newMask << width;
1418 EVT newVT = EVT::getIntegerVT(*DAG.getContext(), bestWidth);
1419 if (newVT.isRound()) {
1420 EVT PtrType = Lod->getOperand(1).getValueType();
1421 SDValue Ptr = Lod->getBasePtr();
1422 if (bestOffset != 0)
1423 Ptr = DAG.getNode(ISD::ADD, dl, PtrType, Lod->getBasePtr(),
1424 DAG.getConstant(bestOffset, dl, PtrType));
1425 unsigned NewAlign = MinAlign(Lod->getAlignment(), bestOffset);
1426 SDValue NewLoad = DAG.getLoad(newVT, dl, Lod->getChain(), Ptr,
1427 Lod->getPointerInfo().getWithOffset(bestOffset),
1428 false, false, false, NewAlign);
1429 return DAG.getSetCC(dl, VT,
1430 DAG.getNode(ISD::AND, dl, newVT, NewLoad,
1431 DAG.getConstant(bestMask.trunc(bestWidth),
1433 DAG.getConstant(0LL, dl, newVT), Cond);
1438 // If the LHS is a ZERO_EXTEND, perform the comparison on the input.
1439 if (N0.getOpcode() == ISD::ZERO_EXTEND) {
1440 unsigned InSize = N0.getOperand(0).getValueType().getSizeInBits();
1442 // If the comparison constant has bits in the upper part, the
1443 // zero-extended value could never match.
1444 if (C1.intersects(APInt::getHighBitsSet(C1.getBitWidth(),
1445 C1.getBitWidth() - InSize))) {
1449 case ISD::SETEQ: return DAG.getConstant(0, dl, VT);
1452 case ISD::SETNE: return DAG.getConstant(1, dl, VT);
1455 // True if the sign bit of C1 is set.
1456 return DAG.getConstant(C1.isNegative(), dl, VT);
1459 // True if the sign bit of C1 isn't set.
1460 return DAG.getConstant(C1.isNonNegative(), dl, VT);
1466 // Otherwise, we can perform the comparison with the low bits.
1474 EVT newVT = N0.getOperand(0).getValueType();
1475 if (DCI.isBeforeLegalizeOps() ||
1476 (isOperationLegal(ISD::SETCC, newVT) &&
1477 getCondCodeAction(Cond, newVT.getSimpleVT()) == Legal)) {
1479 getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), newVT);
1480 SDValue NewConst = DAG.getConstant(C1.trunc(InSize), dl, newVT);
1482 SDValue NewSetCC = DAG.getSetCC(dl, NewSetCCVT, N0.getOperand(0),
1484 return DAG.getBoolExtOrTrunc(NewSetCC, dl, VT, N0.getValueType());
1489 break; // todo, be more careful with signed comparisons
1491 } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1492 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
1493 EVT ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
1494 unsigned ExtSrcTyBits = ExtSrcTy.getSizeInBits();
1495 EVT ExtDstTy = N0.getValueType();
1496 unsigned ExtDstTyBits = ExtDstTy.getSizeInBits();
1498 // If the constant doesn't fit into the number of bits for the source of
1499 // the sign extension, it is impossible for both sides to be equal.
1500 if (C1.getMinSignedBits() > ExtSrcTyBits)
1501 return DAG.getConstant(Cond == ISD::SETNE, dl, VT);
1504 EVT Op0Ty = N0.getOperand(0).getValueType();
1505 if (Op0Ty == ExtSrcTy) {
1506 ZextOp = N0.getOperand(0);
1508 APInt Imm = APInt::getLowBitsSet(ExtDstTyBits, ExtSrcTyBits);
1509 ZextOp = DAG.getNode(ISD::AND, dl, Op0Ty, N0.getOperand(0),
1510 DAG.getConstant(Imm, dl, Op0Ty));
1512 if (!DCI.isCalledByLegalizer())
1513 DCI.AddToWorklist(ZextOp.getNode());
1514 // Otherwise, make this a use of a zext.
1515 return DAG.getSetCC(dl, VT, ZextOp,
1516 DAG.getConstant(C1 & APInt::getLowBitsSet(
1521 } else if ((N1C->isNullValue() || N1C->getAPIntValue() == 1) &&
1522 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
1523 // SETCC (SETCC), [0|1], [EQ|NE] -> SETCC
1524 if (N0.getOpcode() == ISD::SETCC &&
1525 isTypeLegal(VT) && VT.bitsLE(N0.getValueType())) {
1526 bool TrueWhenTrue = (Cond == ISD::SETEQ) ^ (N1C->getAPIntValue() != 1);
1528 return DAG.getNode(ISD::TRUNCATE, dl, VT, N0);
1529 // Invert the condition.
1530 ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get();
1531 CC = ISD::getSetCCInverse(CC,
1532 N0.getOperand(0).getValueType().isInteger());
1533 if (DCI.isBeforeLegalizeOps() ||
1534 isCondCodeLegal(CC, N0.getOperand(0).getSimpleValueType()))
1535 return DAG.getSetCC(dl, VT, N0.getOperand(0), N0.getOperand(1), CC);
1538 if ((N0.getOpcode() == ISD::XOR ||
1539 (N0.getOpcode() == ISD::AND &&
1540 N0.getOperand(0).getOpcode() == ISD::XOR &&
1541 N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
1542 isa<ConstantSDNode>(N0.getOperand(1)) &&
1543 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue() == 1) {
1544 // If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We
1545 // can only do this if the top bits are known zero.
1546 unsigned BitWidth = N0.getValueSizeInBits();
1547 if (DAG.MaskedValueIsZero(N0,
1548 APInt::getHighBitsSet(BitWidth,
1550 // Okay, get the un-inverted input value.
1552 if (N0.getOpcode() == ISD::XOR)
1553 Val = N0.getOperand(0);
1555 assert(N0.getOpcode() == ISD::AND &&
1556 N0.getOperand(0).getOpcode() == ISD::XOR);
1557 // ((X^1)&1)^1 -> X & 1
1558 Val = DAG.getNode(ISD::AND, dl, N0.getValueType(),
1559 N0.getOperand(0).getOperand(0),
1563 return DAG.getSetCC(dl, VT, Val, N1,
1564 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
1566 } else if (N1C->getAPIntValue() == 1 &&
1568 getBooleanContents(N0->getValueType(0)) ==
1569 ZeroOrOneBooleanContent)) {
1571 if (Op0.getOpcode() == ISD::TRUNCATE)
1572 Op0 = Op0.getOperand(0);
1574 if ((Op0.getOpcode() == ISD::XOR) &&
1575 Op0.getOperand(0).getOpcode() == ISD::SETCC &&
1576 Op0.getOperand(1).getOpcode() == ISD::SETCC) {
1577 // (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc)
1578 Cond = (Cond == ISD::SETEQ) ? ISD::SETNE : ISD::SETEQ;
1579 return DAG.getSetCC(dl, VT, Op0.getOperand(0), Op0.getOperand(1),
1582 if (Op0.getOpcode() == ISD::AND &&
1583 isa<ConstantSDNode>(Op0.getOperand(1)) &&
1584 cast<ConstantSDNode>(Op0.getOperand(1))->getAPIntValue() == 1) {
1585 // If this is (X&1) == / != 1, normalize it to (X&1) != / == 0.
1586 if (Op0.getValueType().bitsGT(VT))
1587 Op0 = DAG.getNode(ISD::AND, dl, VT,
1588 DAG.getNode(ISD::TRUNCATE, dl, VT, Op0.getOperand(0)),
1589 DAG.getConstant(1, dl, VT));
1590 else if (Op0.getValueType().bitsLT(VT))
1591 Op0 = DAG.getNode(ISD::AND, dl, VT,
1592 DAG.getNode(ISD::ANY_EXTEND, dl, VT, Op0.getOperand(0)),
1593 DAG.getConstant(1, dl, VT));
1595 return DAG.getSetCC(dl, VT, Op0,
1596 DAG.getConstant(0, dl, Op0.getValueType()),
1597 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
1599 if (Op0.getOpcode() == ISD::AssertZext &&
1600 cast<VTSDNode>(Op0.getOperand(1))->getVT() == MVT::i1)
1601 return DAG.getSetCC(dl, VT, Op0,
1602 DAG.getConstant(0, dl, Op0.getValueType()),
1603 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
1607 APInt MinVal, MaxVal;
1608 unsigned OperandBitSize = N1C->getValueType(0).getSizeInBits();
1609 if (ISD::isSignedIntSetCC(Cond)) {
1610 MinVal = APInt::getSignedMinValue(OperandBitSize);
1611 MaxVal = APInt::getSignedMaxValue(OperandBitSize);
1613 MinVal = APInt::getMinValue(OperandBitSize);
1614 MaxVal = APInt::getMaxValue(OperandBitSize);
1617 // Canonicalize GE/LE comparisons to use GT/LT comparisons.
1618 if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
1619 if (C1 == MinVal) return DAG.getConstant(1, dl, VT); // X >= MIN --> true
1620 // X >= C0 --> X > (C0 - 1)
1622 ISD::CondCode NewCC = (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT;
1623 if ((DCI.isBeforeLegalizeOps() ||
1624 isCondCodeLegal(NewCC, VT.getSimpleVT())) &&
1625 (!N1C->isOpaque() || (N1C->isOpaque() && C.getBitWidth() <= 64 &&
1626 isLegalICmpImmediate(C.getSExtValue())))) {
1627 return DAG.getSetCC(dl, VT, N0,
1628 DAG.getConstant(C, dl, N1.getValueType()),
1633 if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
1634 if (C1 == MaxVal) return DAG.getConstant(1, dl, VT); // X <= MAX --> true
1635 // X <= C0 --> X < (C0 + 1)
1637 ISD::CondCode NewCC = (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT;
1638 if ((DCI.isBeforeLegalizeOps() ||
1639 isCondCodeLegal(NewCC, VT.getSimpleVT())) &&
1640 (!N1C->isOpaque() || (N1C->isOpaque() && C.getBitWidth() <= 64 &&
1641 isLegalICmpImmediate(C.getSExtValue())))) {
1642 return DAG.getSetCC(dl, VT, N0,
1643 DAG.getConstant(C, dl, N1.getValueType()),
1648 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
1649 return DAG.getConstant(0, dl, VT); // X < MIN --> false
1650 if ((Cond == ISD::SETGE || Cond == ISD::SETUGE) && C1 == MinVal)
1651 return DAG.getConstant(1, dl, VT); // X >= MIN --> true
1652 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal)
1653 return DAG.getConstant(0, dl, VT); // X > MAX --> false
1654 if ((Cond == ISD::SETLE || Cond == ISD::SETULE) && C1 == MaxVal)
1655 return DAG.getConstant(1, dl, VT); // X <= MAX --> true
1657 // Canonicalize setgt X, Min --> setne X, Min
1658 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
1659 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETNE);
1660 // Canonicalize setlt X, Max --> setne X, Max
1661 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal)
1662 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETNE);
1664 // If we have setult X, 1, turn it into seteq X, 0
1665 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
1666 return DAG.getSetCC(dl, VT, N0,
1667 DAG.getConstant(MinVal, dl, N0.getValueType()),
1669 // If we have setugt X, Max-1, turn it into seteq X, Max
1670 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
1671 return DAG.getSetCC(dl, VT, N0,
1672 DAG.getConstant(MaxVal, dl, N0.getValueType()),
1675 // If we have "setcc X, C0", check to see if we can shrink the immediate
1678 // SETUGT X, SINTMAX -> SETLT X, 0
1679 if (Cond == ISD::SETUGT &&
1680 C1 == APInt::getSignedMaxValue(OperandBitSize))
1681 return DAG.getSetCC(dl, VT, N0,
1682 DAG.getConstant(0, dl, N1.getValueType()),
1685 // SETULT X, SINTMIN -> SETGT X, -1
1686 if (Cond == ISD::SETULT &&
1687 C1 == APInt::getSignedMinValue(OperandBitSize)) {
1688 SDValue ConstMinusOne =
1689 DAG.getConstant(APInt::getAllOnesValue(OperandBitSize), dl,
1691 return DAG.getSetCC(dl, VT, N0, ConstMinusOne, ISD::SETGT);
1694 // Fold bit comparisons when we can.
1695 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1696 (VT == N0.getValueType() ||
1697 (isTypeLegal(VT) && VT.bitsLE(N0.getValueType()))) &&
1698 N0.getOpcode() == ISD::AND) {
1699 auto &DL = DAG.getDataLayout();
1700 if (ConstantSDNode *AndRHS =
1701 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1702 EVT ShiftTy = DCI.isBeforeLegalize()
1704 : getShiftAmountTy(N0.getValueType(), DL);
1705 if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
1706 // Perform the xform if the AND RHS is a single bit.
1707 if (AndRHS->getAPIntValue().isPowerOf2()) {
1708 return DAG.getNode(ISD::TRUNCATE, dl, VT,
1709 DAG.getNode(ISD::SRL, dl, N0.getValueType(), N0,
1710 DAG.getConstant(AndRHS->getAPIntValue().logBase2(), dl,
1713 } else if (Cond == ISD::SETEQ && C1 == AndRHS->getAPIntValue()) {
1714 // (X & 8) == 8 --> (X & 8) >> 3
1715 // Perform the xform if C1 is a single bit.
1716 if (C1.isPowerOf2()) {
1717 return DAG.getNode(ISD::TRUNCATE, dl, VT,
1718 DAG.getNode(ISD::SRL, dl, N0.getValueType(), N0,
1719 DAG.getConstant(C1.logBase2(), dl,
1726 if (C1.getMinSignedBits() <= 64 &&
1727 !isLegalICmpImmediate(C1.getSExtValue())) {
1728 // (X & -256) == 256 -> (X >> 8) == 1
1729 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1730 N0.getOpcode() == ISD::AND && N0.hasOneUse()) {
1731 if (ConstantSDNode *AndRHS =
1732 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1733 const APInt &AndRHSC = AndRHS->getAPIntValue();
1734 if ((-AndRHSC).isPowerOf2() && (AndRHSC & C1) == C1) {
1735 unsigned ShiftBits = AndRHSC.countTrailingZeros();
1736 auto &DL = DAG.getDataLayout();
1737 EVT ShiftTy = DCI.isBeforeLegalize()
1739 : getShiftAmountTy(N0.getValueType(), DL);
1740 EVT CmpTy = N0.getValueType();
1741 SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0.getOperand(0),
1742 DAG.getConstant(ShiftBits, dl,
1744 SDValue CmpRHS = DAG.getConstant(C1.lshr(ShiftBits), dl, CmpTy);
1745 return DAG.getSetCC(dl, VT, Shift, CmpRHS, Cond);
1748 } else if (Cond == ISD::SETULT || Cond == ISD::SETUGE ||
1749 Cond == ISD::SETULE || Cond == ISD::SETUGT) {
1750 bool AdjOne = (Cond == ISD::SETULE || Cond == ISD::SETUGT);
1751 // X < 0x100000000 -> (X >> 32) < 1
1752 // X >= 0x100000000 -> (X >> 32) >= 1
1753 // X <= 0x0ffffffff -> (X >> 32) < 1
1754 // X > 0x0ffffffff -> (X >> 32) >= 1
1757 ISD::CondCode NewCond = Cond;
1759 ShiftBits = C1.countTrailingOnes();
1761 NewCond = (Cond == ISD::SETULE) ? ISD::SETULT : ISD::SETUGE;
1763 ShiftBits = C1.countTrailingZeros();
1765 NewC = NewC.lshr(ShiftBits);
1766 if (ShiftBits && NewC.getMinSignedBits() <= 64 &&
1767 isLegalICmpImmediate(NewC.getSExtValue())) {
1768 auto &DL = DAG.getDataLayout();
1769 EVT ShiftTy = DCI.isBeforeLegalize()
1771 : getShiftAmountTy(N0.getValueType(), DL);
1772 EVT CmpTy = N0.getValueType();
1773 SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0,
1774 DAG.getConstant(ShiftBits, dl, ShiftTy));
1775 SDValue CmpRHS = DAG.getConstant(NewC, dl, CmpTy);
1776 return DAG.getSetCC(dl, VT, Shift, CmpRHS, NewCond);
1782 if (isa<ConstantFPSDNode>(N0.getNode())) {
1783 // Constant fold or commute setcc.
1784 SDValue O = DAG.FoldSetCC(VT, N0, N1, Cond, dl);
1785 if (O.getNode()) return O;
1786 } else if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1.getNode())) {
1787 // If the RHS of an FP comparison is a constant, simplify it away in
1789 if (CFP->getValueAPF().isNaN()) {
1790 // If an operand is known to be a nan, we can fold it.
1791 switch (ISD::getUnorderedFlavor(Cond)) {
1792 default: llvm_unreachable("Unknown flavor!");
1793 case 0: // Known false.
1794 return DAG.getConstant(0, dl, VT);
1795 case 1: // Known true.
1796 return DAG.getConstant(1, dl, VT);
1797 case 2: // Undefined.
1798 return DAG.getUNDEF(VT);
1802 // Otherwise, we know the RHS is not a NaN. Simplify the node to drop the
1803 // constant if knowing that the operand is non-nan is enough. We prefer to
1804 // have SETO(x,x) instead of SETO(x, 0.0) because this avoids having to
1806 if (Cond == ISD::SETO || Cond == ISD::SETUO)
1807 return DAG.getSetCC(dl, VT, N0, N0, Cond);
1809 // If the condition is not legal, see if we can find an equivalent one
1811 if (!isCondCodeLegal(Cond, N0.getSimpleValueType())) {
1812 // If the comparison was an awkward floating-point == or != and one of
1813 // the comparison operands is infinity or negative infinity, convert the
1814 // condition to a less-awkward <= or >=.
1815 if (CFP->getValueAPF().isInfinity()) {
1816 if (CFP->getValueAPF().isNegative()) {
1817 if (Cond == ISD::SETOEQ &&
1818 isCondCodeLegal(ISD::SETOLE, N0.getSimpleValueType()))
1819 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOLE);
1820 if (Cond == ISD::SETUEQ &&
1821 isCondCodeLegal(ISD::SETOLE, N0.getSimpleValueType()))
1822 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETULE);
1823 if (Cond == ISD::SETUNE &&
1824 isCondCodeLegal(ISD::SETUGT, N0.getSimpleValueType()))
1825 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETUGT);
1826 if (Cond == ISD::SETONE &&
1827 isCondCodeLegal(ISD::SETUGT, N0.getSimpleValueType()))
1828 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOGT);
1830 if (Cond == ISD::SETOEQ &&
1831 isCondCodeLegal(ISD::SETOGE, N0.getSimpleValueType()))
1832 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOGE);
1833 if (Cond == ISD::SETUEQ &&
1834 isCondCodeLegal(ISD::SETOGE, N0.getSimpleValueType()))
1835 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETUGE);
1836 if (Cond == ISD::SETUNE &&
1837 isCondCodeLegal(ISD::SETULT, N0.getSimpleValueType()))
1838 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETULT);
1839 if (Cond == ISD::SETONE &&
1840 isCondCodeLegal(ISD::SETULT, N0.getSimpleValueType()))
1841 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOLT);
1848 // The sext(setcc()) => setcc() optimization relies on the appropriate
1849 // constant being emitted.
1851 switch (getBooleanContents(N0.getValueType())) {
1852 case UndefinedBooleanContent:
1853 case ZeroOrOneBooleanContent:
1854 EqVal = ISD::isTrueWhenEqual(Cond);
1856 case ZeroOrNegativeOneBooleanContent:
1857 EqVal = ISD::isTrueWhenEqual(Cond) ? -1 : 0;
1861 // We can always fold X == X for integer setcc's.
1862 if (N0.getValueType().isInteger()) {
1863 return DAG.getConstant(EqVal, dl, VT);
1865 unsigned UOF = ISD::getUnorderedFlavor(Cond);
1866 if (UOF == 2) // FP operators that are undefined on NaNs.
1867 return DAG.getConstant(EqVal, dl, VT);
1868 if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
1869 return DAG.getConstant(EqVal, dl, VT);
1870 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
1871 // if it is not already.
1872 ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
1873 if (NewCond != Cond && (DCI.isBeforeLegalizeOps() ||
1874 getCondCodeAction(NewCond, N0.getSimpleValueType()) == Legal))
1875 return DAG.getSetCC(dl, VT, N0, N1, NewCond);
1878 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1879 N0.getValueType().isInteger()) {
1880 if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
1881 N0.getOpcode() == ISD::XOR) {
1882 // Simplify (X+Y) == (X+Z) --> Y == Z
1883 if (N0.getOpcode() == N1.getOpcode()) {
1884 if (N0.getOperand(0) == N1.getOperand(0))
1885 return DAG.getSetCC(dl, VT, N0.getOperand(1), N1.getOperand(1), Cond);
1886 if (N0.getOperand(1) == N1.getOperand(1))
1887 return DAG.getSetCC(dl, VT, N0.getOperand(0), N1.getOperand(0), Cond);
1888 if (DAG.isCommutativeBinOp(N0.getOpcode())) {
1889 // If X op Y == Y op X, try other combinations.
1890 if (N0.getOperand(0) == N1.getOperand(1))
1891 return DAG.getSetCC(dl, VT, N0.getOperand(1), N1.getOperand(0),
1893 if (N0.getOperand(1) == N1.getOperand(0))
1894 return DAG.getSetCC(dl, VT, N0.getOperand(0), N1.getOperand(1),
1899 // If RHS is a legal immediate value for a compare instruction, we need
1900 // to be careful about increasing register pressure needlessly.
1901 bool LegalRHSImm = false;
1903 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) {
1904 if (ConstantSDNode *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1905 // Turn (X+C1) == C2 --> X == C2-C1
1906 if (N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse()) {
1907 return DAG.getSetCC(dl, VT, N0.getOperand(0),
1908 DAG.getConstant(RHSC->getAPIntValue()-
1909 LHSR->getAPIntValue(),
1910 dl, N0.getValueType()), Cond);
1913 // Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0.
1914 if (N0.getOpcode() == ISD::XOR)
1915 // If we know that all of the inverted bits are zero, don't bother
1916 // performing the inversion.
1917 if (DAG.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getAPIntValue()))
1919 DAG.getSetCC(dl, VT, N0.getOperand(0),
1920 DAG.getConstant(LHSR->getAPIntValue() ^
1921 RHSC->getAPIntValue(),
1922 dl, N0.getValueType()),
1926 // Turn (C1-X) == C2 --> X == C1-C2
1927 if (ConstantSDNode *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) {
1928 if (N0.getOpcode() == ISD::SUB && N0.getNode()->hasOneUse()) {
1930 DAG.getSetCC(dl, VT, N0.getOperand(1),
1931 DAG.getConstant(SUBC->getAPIntValue() -
1932 RHSC->getAPIntValue(),
1933 dl, N0.getValueType()),
1938 // Could RHSC fold directly into a compare?
1939 if (RHSC->getValueType(0).getSizeInBits() <= 64)
1940 LegalRHSImm = isLegalICmpImmediate(RHSC->getSExtValue());
1943 // Simplify (X+Z) == X --> Z == 0
1944 // Don't do this if X is an immediate that can fold into a cmp
1945 // instruction and X+Z has other uses. It could be an induction variable
1946 // chain, and the transform would increase register pressure.
1947 if (!LegalRHSImm || N0.getNode()->hasOneUse()) {
1948 if (N0.getOperand(0) == N1)
1949 return DAG.getSetCC(dl, VT, N0.getOperand(1),
1950 DAG.getConstant(0, dl, N0.getValueType()), Cond);
1951 if (N0.getOperand(1) == N1) {
1952 if (DAG.isCommutativeBinOp(N0.getOpcode()))
1953 return DAG.getSetCC(dl, VT, N0.getOperand(0),
1954 DAG.getConstant(0, dl, N0.getValueType()),
1956 if (N0.getNode()->hasOneUse()) {
1957 assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
1958 auto &DL = DAG.getDataLayout();
1959 // (Z-X) == X --> Z == X<<1
1960 SDValue SH = DAG.getNode(
1961 ISD::SHL, dl, N1.getValueType(), N1,
1962 DAG.getConstant(1, dl,
1963 getShiftAmountTy(N1.getValueType(), DL)));
1964 if (!DCI.isCalledByLegalizer())
1965 DCI.AddToWorklist(SH.getNode());
1966 return DAG.getSetCC(dl, VT, N0.getOperand(0), SH, Cond);
1972 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
1973 N1.getOpcode() == ISD::XOR) {
1974 // Simplify X == (X+Z) --> Z == 0
1975 if (N1.getOperand(0) == N0)
1976 return DAG.getSetCC(dl, VT, N1.getOperand(1),
1977 DAG.getConstant(0, dl, N1.getValueType()), Cond);
1978 if (N1.getOperand(1) == N0) {
1979 if (DAG.isCommutativeBinOp(N1.getOpcode()))
1980 return DAG.getSetCC(dl, VT, N1.getOperand(0),
1981 DAG.getConstant(0, dl, N1.getValueType()), Cond);
1982 if (N1.getNode()->hasOneUse()) {
1983 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
1984 auto &DL = DAG.getDataLayout();
1985 // X == (Z-X) --> X<<1 == Z
1986 SDValue SH = DAG.getNode(
1987 ISD::SHL, dl, N1.getValueType(), N0,
1988 DAG.getConstant(1, dl, getShiftAmountTy(N0.getValueType(), DL)));
1989 if (!DCI.isCalledByLegalizer())
1990 DCI.AddToWorklist(SH.getNode());
1991 return DAG.getSetCC(dl, VT, SH, N1.getOperand(0), Cond);
1996 // Simplify x&y == y to x&y != 0 if y has exactly one bit set.
1997 // Note that where y is variable and is known to have at most
1998 // one bit set (for example, if it is z&1) we cannot do this;
1999 // the expressions are not equivalent when y==0.
2000 if (N0.getOpcode() == ISD::AND)
2001 if (N0.getOperand(0) == N1 || N0.getOperand(1) == N1) {
2002 if (ValueHasExactlyOneBitSet(N1, DAG)) {
2003 Cond = ISD::getSetCCInverse(Cond, /*isInteger=*/true);
2004 if (DCI.isBeforeLegalizeOps() ||
2005 isCondCodeLegal(Cond, N0.getSimpleValueType())) {
2006 SDValue Zero = DAG.getConstant(0, dl, N1.getValueType());
2007 return DAG.getSetCC(dl, VT, N0, Zero, Cond);
2011 if (N1.getOpcode() == ISD::AND)
2012 if (N1.getOperand(0) == N0 || N1.getOperand(1) == N0) {
2013 if (ValueHasExactlyOneBitSet(N0, DAG)) {
2014 Cond = ISD::getSetCCInverse(Cond, /*isInteger=*/true);
2015 if (DCI.isBeforeLegalizeOps() ||
2016 isCondCodeLegal(Cond, N1.getSimpleValueType())) {
2017 SDValue Zero = DAG.getConstant(0, dl, N0.getValueType());
2018 return DAG.getSetCC(dl, VT, N1, Zero, Cond);
2024 // Fold away ALL boolean setcc's.
2026 if (N0.getValueType() == MVT::i1 && foldBooleans) {
2028 default: llvm_unreachable("Unknown integer setcc!");
2029 case ISD::SETEQ: // X == Y -> ~(X^Y)
2030 Temp = DAG.getNode(ISD::XOR, dl, MVT::i1, N0, N1);
2031 N0 = DAG.getNOT(dl, Temp, MVT::i1);
2032 if (!DCI.isCalledByLegalizer())
2033 DCI.AddToWorklist(Temp.getNode());
2035 case ISD::SETNE: // X != Y --> (X^Y)
2036 N0 = DAG.getNode(ISD::XOR, dl, MVT::i1, N0, N1);
2038 case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> ~X & Y
2039 case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> ~X & Y
2040 Temp = DAG.getNOT(dl, N0, MVT::i1);
2041 N0 = DAG.getNode(ISD::AND, dl, MVT::i1, N1, Temp);
2042 if (!DCI.isCalledByLegalizer())
2043 DCI.AddToWorklist(Temp.getNode());
2045 case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> ~Y & X
2046 case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> ~Y & X
2047 Temp = DAG.getNOT(dl, N1, MVT::i1);
2048 N0 = DAG.getNode(ISD::AND, dl, MVT::i1, N0, Temp);
2049 if (!DCI.isCalledByLegalizer())
2050 DCI.AddToWorklist(Temp.getNode());
2052 case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> ~X | Y
2053 case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> ~X | Y
2054 Temp = DAG.getNOT(dl, N0, MVT::i1);
2055 N0 = DAG.getNode(ISD::OR, dl, MVT::i1, N1, Temp);
2056 if (!DCI.isCalledByLegalizer())
2057 DCI.AddToWorklist(Temp.getNode());
2059 case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> ~Y | X
2060 case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> ~Y | X
2061 Temp = DAG.getNOT(dl, N1, MVT::i1);
2062 N0 = DAG.getNode(ISD::OR, dl, MVT::i1, N0, Temp);
2065 if (VT != MVT::i1) {
2066 if (!DCI.isCalledByLegalizer())
2067 DCI.AddToWorklist(N0.getNode());
2068 // FIXME: If running after legalize, we probably can't do this.
2069 N0 = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, N0);
2074 // Could not fold it.
2078 /// isGAPlusOffset - Returns true (and the GlobalValue and the offset) if the
2079 /// node is a GlobalAddress + offset.
2080 bool TargetLowering::isGAPlusOffset(SDNode *N, const GlobalValue *&GA,
2081 int64_t &Offset) const {
2082 if (isa<GlobalAddressSDNode>(N)) {
2083 GlobalAddressSDNode *GASD = cast<GlobalAddressSDNode>(N);
2084 GA = GASD->getGlobal();
2085 Offset += GASD->getOffset();
2089 if (N->getOpcode() == ISD::ADD) {
2090 SDValue N1 = N->getOperand(0);
2091 SDValue N2 = N->getOperand(1);
2092 if (isGAPlusOffset(N1.getNode(), GA, Offset)) {
2093 ConstantSDNode *V = dyn_cast<ConstantSDNode>(N2);
2095 Offset += V->getSExtValue();
2098 } else if (isGAPlusOffset(N2.getNode(), GA, Offset)) {
2099 ConstantSDNode *V = dyn_cast<ConstantSDNode>(N1);
2101 Offset += V->getSExtValue();
2111 SDValue TargetLowering::
2112 PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const {
2113 // Default implementation: no optimization.
2117 //===----------------------------------------------------------------------===//
2118 // Inline Assembler Implementation Methods
2119 //===----------------------------------------------------------------------===//
2121 TargetLowering::ConstraintType
2122 TargetLowering::getConstraintType(StringRef Constraint) const {
2123 unsigned S = Constraint.size();
2126 switch (Constraint[0]) {
2128 case 'r': return C_RegisterClass;
2130 case 'o': // offsetable
2131 case 'V': // not offsetable
2133 case 'i': // Simple Integer or Relocatable Constant
2134 case 'n': // Simple Integer
2135 case 'E': // Floating Point Constant
2136 case 'F': // Floating Point Constant
2137 case 's': // Relocatable Constant
2138 case 'p': // Address.
2139 case 'X': // Allow ANY value.
2140 case 'I': // Target registers.
2154 if (S > 1 && Constraint[0] == '{' && Constraint[S-1] == '}') {
2155 if (S == 8 && Constraint.substr(1, 6) == "memory") // "{memory}"
2162 /// LowerXConstraint - try to replace an X constraint, which matches anything,
2163 /// with another that has more specific requirements based on the type of the
2164 /// corresponding operand.
2165 const char *TargetLowering::LowerXConstraint(EVT ConstraintVT) const{
2166 if (ConstraintVT.isInteger())
2168 if (ConstraintVT.isFloatingPoint())
2169 return "f"; // works for many targets
2173 /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
2174 /// vector. If it is invalid, don't add anything to Ops.
2175 void TargetLowering::LowerAsmOperandForConstraint(SDValue Op,
2176 std::string &Constraint,
2177 std::vector<SDValue> &Ops,
2178 SelectionDAG &DAG) const {
2180 if (Constraint.length() > 1) return;
2182 char ConstraintLetter = Constraint[0];
2183 switch (ConstraintLetter) {
2185 case 'X': // Allows any operand; labels (basic block) use this.
2186 if (Op.getOpcode() == ISD::BasicBlock) {
2191 case 'i': // Simple Integer or Relocatable Constant
2192 case 'n': // Simple Integer
2193 case 's': { // Relocatable Constant
2194 // These operands are interested in values of the form (GV+C), where C may
2195 // be folded in as an offset of GV, or it may be explicitly added. Also, it
2196 // is possible and fine if either GV or C are missing.
2197 ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op);
2198 GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Op);
2200 // If we have "(add GV, C)", pull out GV/C
2201 if (Op.getOpcode() == ISD::ADD) {
2202 C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
2203 GA = dyn_cast<GlobalAddressSDNode>(Op.getOperand(0));
2205 C = dyn_cast<ConstantSDNode>(Op.getOperand(0));
2206 GA = dyn_cast<GlobalAddressSDNode>(Op.getOperand(1));
2209 C = nullptr, GA = nullptr;
2212 // If we find a valid operand, map to the TargetXXX version so that the
2213 // value itself doesn't get selected.
2214 if (GA) { // Either &GV or &GV+C
2215 if (ConstraintLetter != 'n') {
2216 int64_t Offs = GA->getOffset();
2217 if (C) Offs += C->getZExtValue();
2218 Ops.push_back(DAG.getTargetGlobalAddress(GA->getGlobal(),
2219 C ? SDLoc(C) : SDLoc(),
2220 Op.getValueType(), Offs));
2224 if (C) { // just C, no GV.
2225 // Simple constants are not allowed for 's'.
2226 if (ConstraintLetter != 's') {
2227 // gcc prints these as sign extended. Sign extend value to 64 bits
2228 // now; without this it would get ZExt'd later in
2229 // ScheduleDAGSDNodes::EmitNode, which is very generic.
2230 Ops.push_back(DAG.getTargetConstant(C->getAPIntValue().getSExtValue(),
2231 SDLoc(C), MVT::i64));
2240 std::pair<unsigned, const TargetRegisterClass *>
2241 TargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *RI,
2242 StringRef Constraint,
2244 if (Constraint.empty() || Constraint[0] != '{')
2245 return std::make_pair(0u, static_cast<TargetRegisterClass*>(nullptr));
2246 assert(*(Constraint.end()-1) == '}' && "Not a brace enclosed constraint?");
2248 // Remove the braces from around the name.
2249 StringRef RegName(Constraint.data()+1, Constraint.size()-2);
2251 std::pair<unsigned, const TargetRegisterClass*> R =
2252 std::make_pair(0u, static_cast<const TargetRegisterClass*>(nullptr));
2254 // Figure out which register class contains this reg.
2255 for (TargetRegisterInfo::regclass_iterator RCI = RI->regclass_begin(),
2256 E = RI->regclass_end(); RCI != E; ++RCI) {
2257 const TargetRegisterClass *RC = *RCI;
2259 // If none of the value types for this register class are valid, we
2260 // can't use it. For example, 64-bit reg classes on 32-bit targets.
2264 for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
2266 if (RegName.equals_lower(RI->getName(*I))) {
2267 std::pair<unsigned, const TargetRegisterClass*> S =
2268 std::make_pair(*I, RC);
2270 // If this register class has the requested value type, return it,
2271 // otherwise keep searching and return the first class found
2272 // if no other is found which explicitly has the requested type.
2273 if (RC->hasType(VT))
2284 //===----------------------------------------------------------------------===//
2285 // Constraint Selection.
2287 /// isMatchingInputConstraint - Return true of this is an input operand that is
2288 /// a matching constraint like "4".
2289 bool TargetLowering::AsmOperandInfo::isMatchingInputConstraint() const {
2290 assert(!ConstraintCode.empty() && "No known constraint!");
2291 return isdigit(static_cast<unsigned char>(ConstraintCode[0]));
2294 /// getMatchedOperand - If this is an input matching constraint, this method
2295 /// returns the output operand it matches.
2296 unsigned TargetLowering::AsmOperandInfo::getMatchedOperand() const {
2297 assert(!ConstraintCode.empty() && "No known constraint!");
2298 return atoi(ConstraintCode.c_str());
2302 /// ParseConstraints - Split up the constraint string from the inline
2303 /// assembly value into the specific constraints and their prefixes,
2304 /// and also tie in the associated operand values.
2305 /// If this returns an empty vector, and if the constraint string itself
2306 /// isn't empty, there was an error parsing.
2307 TargetLowering::AsmOperandInfoVector
2308 TargetLowering::ParseConstraints(const DataLayout &DL,
2309 const TargetRegisterInfo *TRI,
2310 ImmutableCallSite CS) const {
2311 /// ConstraintOperands - Information about all of the constraints.
2312 AsmOperandInfoVector ConstraintOperands;
2313 const InlineAsm *IA = cast<InlineAsm>(CS.getCalledValue());
2314 unsigned maCount = 0; // Largest number of multiple alternative constraints.
2316 // Do a prepass over the constraints, canonicalizing them, and building up the
2317 // ConstraintOperands list.
2318 unsigned ArgNo = 0; // ArgNo - The argument of the CallInst.
2319 unsigned ResNo = 0; // ResNo - The result number of the next output.
2321 for (InlineAsm::ConstraintInfo &CI : IA->ParseConstraints()) {
2322 ConstraintOperands.emplace_back(std::move(CI));
2323 AsmOperandInfo &OpInfo = ConstraintOperands.back();
2325 // Update multiple alternative constraint count.
2326 if (OpInfo.multipleAlternatives.size() > maCount)
2327 maCount = OpInfo.multipleAlternatives.size();
2329 OpInfo.ConstraintVT = MVT::Other;
2331 // Compute the value type for each operand.
2332 switch (OpInfo.Type) {
2333 case InlineAsm::isOutput:
2334 // Indirect outputs just consume an argument.
2335 if (OpInfo.isIndirect) {
2336 OpInfo.CallOperandVal = const_cast<Value *>(CS.getArgument(ArgNo++));
2340 // The return value of the call is this value. As such, there is no
2341 // corresponding argument.
2342 assert(!CS.getType()->isVoidTy() &&
2344 if (StructType *STy = dyn_cast<StructType>(CS.getType())) {
2345 OpInfo.ConstraintVT =
2346 getSimpleValueType(DL, STy->getElementType(ResNo));
2348 assert(ResNo == 0 && "Asm only has one result!");
2349 OpInfo.ConstraintVT = getSimpleValueType(DL, CS.getType());
2353 case InlineAsm::isInput:
2354 OpInfo.CallOperandVal = const_cast<Value *>(CS.getArgument(ArgNo++));
2356 case InlineAsm::isClobber:
2361 if (OpInfo.CallOperandVal) {
2362 llvm::Type *OpTy = OpInfo.CallOperandVal->getType();
2363 if (OpInfo.isIndirect) {
2364 llvm::PointerType *PtrTy = dyn_cast<PointerType>(OpTy);
2366 report_fatal_error("Indirect operand for inline asm not a pointer!");
2367 OpTy = PtrTy->getElementType();
2370 // Look for vector wrapped in a struct. e.g. { <16 x i8> }.
2371 if (StructType *STy = dyn_cast<StructType>(OpTy))
2372 if (STy->getNumElements() == 1)
2373 OpTy = STy->getElementType(0);
2375 // If OpTy is not a single value, it may be a struct/union that we
2376 // can tile with integers.
2377 if (!OpTy->isSingleValueType() && OpTy->isSized()) {
2378 unsigned BitSize = DL.getTypeSizeInBits(OpTy);
2387 OpInfo.ConstraintVT =
2388 MVT::getVT(IntegerType::get(OpTy->getContext(), BitSize), true);
2391 } else if (PointerType *PT = dyn_cast<PointerType>(OpTy)) {
2392 unsigned PtrSize = DL.getPointerSizeInBits(PT->getAddressSpace());
2393 OpInfo.ConstraintVT = MVT::getIntegerVT(PtrSize);
2395 OpInfo.ConstraintVT = MVT::getVT(OpTy, true);
2400 // If we have multiple alternative constraints, select the best alternative.
2401 if (!ConstraintOperands.empty()) {
2403 unsigned bestMAIndex = 0;
2404 int bestWeight = -1;
2405 // weight: -1 = invalid match, and 0 = so-so match to 5 = good match.
2408 // Compute the sums of the weights for each alternative, keeping track
2409 // of the best (highest weight) one so far.
2410 for (maIndex = 0; maIndex < maCount; ++maIndex) {
2412 for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
2413 cIndex != eIndex; ++cIndex) {
2414 AsmOperandInfo& OpInfo = ConstraintOperands[cIndex];
2415 if (OpInfo.Type == InlineAsm::isClobber)
2418 // If this is an output operand with a matching input operand,
2419 // look up the matching input. If their types mismatch, e.g. one
2420 // is an integer, the other is floating point, or their sizes are
2421 // different, flag it as an maCantMatch.
2422 if (OpInfo.hasMatchingInput()) {
2423 AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
2424 if (OpInfo.ConstraintVT != Input.ConstraintVT) {
2425 if ((OpInfo.ConstraintVT.isInteger() !=
2426 Input.ConstraintVT.isInteger()) ||
2427 (OpInfo.ConstraintVT.getSizeInBits() !=
2428 Input.ConstraintVT.getSizeInBits())) {
2429 weightSum = -1; // Can't match.
2434 weight = getMultipleConstraintMatchWeight(OpInfo, maIndex);
2439 weightSum += weight;
2442 if (weightSum > bestWeight) {
2443 bestWeight = weightSum;
2444 bestMAIndex = maIndex;
2448 // Now select chosen alternative in each constraint.
2449 for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
2450 cIndex != eIndex; ++cIndex) {
2451 AsmOperandInfo& cInfo = ConstraintOperands[cIndex];
2452 if (cInfo.Type == InlineAsm::isClobber)
2454 cInfo.selectAlternative(bestMAIndex);
2459 // Check and hook up tied operands, choose constraint code to use.
2460 for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
2461 cIndex != eIndex; ++cIndex) {
2462 AsmOperandInfo& OpInfo = ConstraintOperands[cIndex];
2464 // If this is an output operand with a matching input operand, look up the
2465 // matching input. If their types mismatch, e.g. one is an integer, the
2466 // other is floating point, or their sizes are different, flag it as an
2468 if (OpInfo.hasMatchingInput()) {
2469 AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
2471 if (OpInfo.ConstraintVT != Input.ConstraintVT) {
2472 std::pair<unsigned, const TargetRegisterClass *> MatchRC =
2473 getRegForInlineAsmConstraint(TRI, OpInfo.ConstraintCode,
2474 OpInfo.ConstraintVT);
2475 std::pair<unsigned, const TargetRegisterClass *> InputRC =
2476 getRegForInlineAsmConstraint(TRI, Input.ConstraintCode,
2477 Input.ConstraintVT);
2478 if ((OpInfo.ConstraintVT.isInteger() !=
2479 Input.ConstraintVT.isInteger()) ||
2480 (MatchRC.second != InputRC.second)) {
2481 report_fatal_error("Unsupported asm: input constraint"
2482 " with a matching output constraint of"
2483 " incompatible type!");
2490 return ConstraintOperands;
2494 /// getConstraintGenerality - Return an integer indicating how general CT
2496 static unsigned getConstraintGenerality(TargetLowering::ConstraintType CT) {
2498 case TargetLowering::C_Other:
2499 case TargetLowering::C_Unknown:
2501 case TargetLowering::C_Register:
2503 case TargetLowering::C_RegisterClass:
2505 case TargetLowering::C_Memory:
2508 llvm_unreachable("Invalid constraint type");
2511 /// Examine constraint type and operand type and determine a weight value.
2512 /// This object must already have been set up with the operand type
2513 /// and the current alternative constraint selected.
2514 TargetLowering::ConstraintWeight
2515 TargetLowering::getMultipleConstraintMatchWeight(
2516 AsmOperandInfo &info, int maIndex) const {
2517 InlineAsm::ConstraintCodeVector *rCodes;
2518 if (maIndex >= (int)info.multipleAlternatives.size())
2519 rCodes = &info.Codes;
2521 rCodes = &info.multipleAlternatives[maIndex].Codes;
2522 ConstraintWeight BestWeight = CW_Invalid;
2524 // Loop over the options, keeping track of the most general one.
2525 for (unsigned i = 0, e = rCodes->size(); i != e; ++i) {
2526 ConstraintWeight weight =
2527 getSingleConstraintMatchWeight(info, (*rCodes)[i].c_str());
2528 if (weight > BestWeight)
2529 BestWeight = weight;
2535 /// Examine constraint type and operand type and determine a weight value.
2536 /// This object must already have been set up with the operand type
2537 /// and the current alternative constraint selected.
2538 TargetLowering::ConstraintWeight
2539 TargetLowering::getSingleConstraintMatchWeight(
2540 AsmOperandInfo &info, const char *constraint) const {
2541 ConstraintWeight weight = CW_Invalid;
2542 Value *CallOperandVal = info.CallOperandVal;
2543 // If we don't have a value, we can't do a match,
2544 // but allow it at the lowest weight.
2545 if (!CallOperandVal)
2547 // Look at the constraint type.
2548 switch (*constraint) {
2549 case 'i': // immediate integer.
2550 case 'n': // immediate integer with a known value.
2551 if (isa<ConstantInt>(CallOperandVal))
2552 weight = CW_Constant;
2554 case 's': // non-explicit intregal immediate.
2555 if (isa<GlobalValue>(CallOperandVal))
2556 weight = CW_Constant;
2558 case 'E': // immediate float if host format.
2559 case 'F': // immediate float.
2560 if (isa<ConstantFP>(CallOperandVal))
2561 weight = CW_Constant;
2563 case '<': // memory operand with autodecrement.
2564 case '>': // memory operand with autoincrement.
2565 case 'm': // memory operand.
2566 case 'o': // offsettable memory operand
2567 case 'V': // non-offsettable memory operand
2570 case 'r': // general register.
2571 case 'g': // general register, memory operand or immediate integer.
2572 // note: Clang converts "g" to "imr".
2573 if (CallOperandVal->getType()->isIntegerTy())
2574 weight = CW_Register;
2576 case 'X': // any operand.
2578 weight = CW_Default;
2584 /// ChooseConstraint - If there are multiple different constraints that we
2585 /// could pick for this operand (e.g. "imr") try to pick the 'best' one.
2586 /// This is somewhat tricky: constraints fall into four classes:
2587 /// Other -> immediates and magic values
2588 /// Register -> one specific register
2589 /// RegisterClass -> a group of regs
2590 /// Memory -> memory
2591 /// Ideally, we would pick the most specific constraint possible: if we have
2592 /// something that fits into a register, we would pick it. The problem here
2593 /// is that if we have something that could either be in a register or in
2594 /// memory that use of the register could cause selection of *other*
2595 /// operands to fail: they might only succeed if we pick memory. Because of
2596 /// this the heuristic we use is:
2598 /// 1) If there is an 'other' constraint, and if the operand is valid for
2599 /// that constraint, use it. This makes us take advantage of 'i'
2600 /// constraints when available.
2601 /// 2) Otherwise, pick the most general constraint present. This prefers
2602 /// 'm' over 'r', for example.
2604 static void ChooseConstraint(TargetLowering::AsmOperandInfo &OpInfo,
2605 const TargetLowering &TLI,
2606 SDValue Op, SelectionDAG *DAG) {
2607 assert(OpInfo.Codes.size() > 1 && "Doesn't have multiple constraint options");
2608 unsigned BestIdx = 0;
2609 TargetLowering::ConstraintType BestType = TargetLowering::C_Unknown;
2610 int BestGenerality = -1;
2612 // Loop over the options, keeping track of the most general one.
2613 for (unsigned i = 0, e = OpInfo.Codes.size(); i != e; ++i) {
2614 TargetLowering::ConstraintType CType =
2615 TLI.getConstraintType(OpInfo.Codes[i]);
2617 // If this is an 'other' constraint, see if the operand is valid for it.
2618 // For example, on X86 we might have an 'rI' constraint. If the operand
2619 // is an integer in the range [0..31] we want to use I (saving a load
2620 // of a register), otherwise we must use 'r'.
2621 if (CType == TargetLowering::C_Other && Op.getNode()) {
2622 assert(OpInfo.Codes[i].size() == 1 &&
2623 "Unhandled multi-letter 'other' constraint");
2624 std::vector<SDValue> ResultOps;
2625 TLI.LowerAsmOperandForConstraint(Op, OpInfo.Codes[i],
2627 if (!ResultOps.empty()) {
2634 // Things with matching constraints can only be registers, per gcc
2635 // documentation. This mainly affects "g" constraints.
2636 if (CType == TargetLowering::C_Memory && OpInfo.hasMatchingInput())
2639 // This constraint letter is more general than the previous one, use it.
2640 int Generality = getConstraintGenerality(CType);
2641 if (Generality > BestGenerality) {
2644 BestGenerality = Generality;
2648 OpInfo.ConstraintCode = OpInfo.Codes[BestIdx];
2649 OpInfo.ConstraintType = BestType;
2652 /// ComputeConstraintToUse - Determines the constraint code and constraint
2653 /// type to use for the specific AsmOperandInfo, setting
2654 /// OpInfo.ConstraintCode and OpInfo.ConstraintType.
2655 void TargetLowering::ComputeConstraintToUse(AsmOperandInfo &OpInfo,
2657 SelectionDAG *DAG) const {
2658 assert(!OpInfo.Codes.empty() && "Must have at least one constraint");
2660 // Single-letter constraints ('r') are very common.
2661 if (OpInfo.Codes.size() == 1) {
2662 OpInfo.ConstraintCode = OpInfo.Codes[0];
2663 OpInfo.ConstraintType = getConstraintType(OpInfo.ConstraintCode);
2665 ChooseConstraint(OpInfo, *this, Op, DAG);
2668 // 'X' matches anything.
2669 if (OpInfo.ConstraintCode == "X" && OpInfo.CallOperandVal) {
2670 // Labels and constants are handled elsewhere ('X' is the only thing
2671 // that matches labels). For Functions, the type here is the type of
2672 // the result, which is not what we want to look at; leave them alone.
2673 Value *v = OpInfo.CallOperandVal;
2674 if (isa<BasicBlock>(v) || isa<ConstantInt>(v) || isa<Function>(v)) {
2675 OpInfo.CallOperandVal = v;
2679 // Otherwise, try to resolve it to something we know about by looking at
2680 // the actual operand type.
2681 if (const char *Repl = LowerXConstraint(OpInfo.ConstraintVT)) {
2682 OpInfo.ConstraintCode = Repl;
2683 OpInfo.ConstraintType = getConstraintType(OpInfo.ConstraintCode);
2688 /// \brief Given an exact SDIV by a constant, create a multiplication
2689 /// with the multiplicative inverse of the constant.
2690 static SDValue BuildExactSDIV(const TargetLowering &TLI, SDValue Op1, APInt d,
2691 SDLoc dl, SelectionDAG &DAG,
2692 std::vector<SDNode *> &Created) {
2693 assert(d != 0 && "Division by zero!");
2695 // Shift the value upfront if it is even, so the LSB is one.
2696 unsigned ShAmt = d.countTrailingZeros();
2698 // TODO: For UDIV use SRL instead of SRA.
2700 DAG.getConstant(ShAmt, dl, TLI.getShiftAmountTy(Op1.getValueType(),
2701 DAG.getDataLayout()));
2703 Flags.setExact(true);
2704 Op1 = DAG.getNode(ISD::SRA, dl, Op1.getValueType(), Op1, Amt, &Flags);
2705 Created.push_back(Op1.getNode());
2709 // Calculate the multiplicative inverse, using Newton's method.
2711 while ((t = d*xn) != 1)
2712 xn *= APInt(d.getBitWidth(), 2) - t;
2714 SDValue Op2 = DAG.getConstant(xn, dl, Op1.getValueType());
2715 SDValue Mul = DAG.getNode(ISD::MUL, dl, Op1.getValueType(), Op1, Op2);
2716 Created.push_back(Mul.getNode());
2720 /// \brief Given an ISD::SDIV node expressing a divide by constant,
2721 /// return a DAG expression to select that will generate the same value by
2722 /// multiplying by a magic number.
2723 /// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide".
2724 SDValue TargetLowering::BuildSDIV(SDNode *N, const APInt &Divisor,
2725 SelectionDAG &DAG, bool IsAfterLegalization,
2726 std::vector<SDNode *> *Created) const {
2727 assert(Created && "No vector to hold sdiv ops.");
2729 EVT VT = N->getValueType(0);
2732 // Check to see if we can do this.
2733 // FIXME: We should be more aggressive here.
2734 if (!isTypeLegal(VT))
2737 // If the sdiv has an 'exact' bit we can use a simpler lowering.
2738 if (cast<BinaryWithFlagsSDNode>(N)->Flags.hasExact())
2739 return BuildExactSDIV(*this, N->getOperand(0), Divisor, dl, DAG, *Created);
2741 APInt::ms magics = Divisor.magic();
2743 // Multiply the numerator (operand 0) by the magic value
2744 // FIXME: We should support doing a MUL in a wider type
2746 if (IsAfterLegalization ? isOperationLegal(ISD::MULHS, VT) :
2747 isOperationLegalOrCustom(ISD::MULHS, VT))
2748 Q = DAG.getNode(ISD::MULHS, dl, VT, N->getOperand(0),
2749 DAG.getConstant(magics.m, dl, VT));
2750 else if (IsAfterLegalization ? isOperationLegal(ISD::SMUL_LOHI, VT) :
2751 isOperationLegalOrCustom(ISD::SMUL_LOHI, VT))
2752 Q = SDValue(DAG.getNode(ISD::SMUL_LOHI, dl, DAG.getVTList(VT, VT),
2754 DAG.getConstant(magics.m, dl, VT)).getNode(), 1);
2756 return SDValue(); // No mulhs or equvialent
2757 // If d > 0 and m < 0, add the numerator
2758 if (Divisor.isStrictlyPositive() && magics.m.isNegative()) {
2759 Q = DAG.getNode(ISD::ADD, dl, VT, Q, N->getOperand(0));
2760 Created->push_back(Q.getNode());
2762 // If d < 0 and m > 0, subtract the numerator.
2763 if (Divisor.isNegative() && magics.m.isStrictlyPositive()) {
2764 Q = DAG.getNode(ISD::SUB, dl, VT, Q, N->getOperand(0));
2765 Created->push_back(Q.getNode());
2767 auto &DL = DAG.getDataLayout();
2768 // Shift right algebraic if shift value is nonzero
2771 ISD::SRA, dl, VT, Q,
2772 DAG.getConstant(magics.s, dl, getShiftAmountTy(Q.getValueType(), DL)));
2773 Created->push_back(Q.getNode());
2775 // Extract the sign bit and add it to the quotient
2777 DAG.getNode(ISD::SRL, dl, VT, Q,
2778 DAG.getConstant(VT.getScalarSizeInBits() - 1, dl,
2779 getShiftAmountTy(Q.getValueType(), DL)));
2780 Created->push_back(T.getNode());
2781 return DAG.getNode(ISD::ADD, dl, VT, Q, T);
2784 /// \brief Given an ISD::UDIV node expressing a divide by constant,
2785 /// return a DAG expression to select that will generate the same value by
2786 /// multiplying by a magic number.
2787 /// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide".
2788 SDValue TargetLowering::BuildUDIV(SDNode *N, const APInt &Divisor,
2789 SelectionDAG &DAG, bool IsAfterLegalization,
2790 std::vector<SDNode *> *Created) const {
2791 assert(Created && "No vector to hold udiv ops.");
2793 EVT VT = N->getValueType(0);
2795 auto &DL = DAG.getDataLayout();
2797 // Check to see if we can do this.
2798 // FIXME: We should be more aggressive here.
2799 if (!isTypeLegal(VT))
2802 // FIXME: We should use a narrower constant when the upper
2803 // bits are known to be zero.
2804 APInt::mu magics = Divisor.magicu();
2806 SDValue Q = N->getOperand(0);
2808 // If the divisor is even, we can avoid using the expensive fixup by shifting
2809 // the divided value upfront.
2810 if (magics.a != 0 && !Divisor[0]) {
2811 unsigned Shift = Divisor.countTrailingZeros();
2813 ISD::SRL, dl, VT, Q,
2814 DAG.getConstant(Shift, dl, getShiftAmountTy(Q.getValueType(), DL)));
2815 Created->push_back(Q.getNode());
2817 // Get magic number for the shifted divisor.
2818 magics = Divisor.lshr(Shift).magicu(Shift);
2819 assert(magics.a == 0 && "Should use cheap fixup now");
2822 // Multiply the numerator (operand 0) by the magic value
2823 // FIXME: We should support doing a MUL in a wider type
2824 if (IsAfterLegalization ? isOperationLegal(ISD::MULHU, VT) :
2825 isOperationLegalOrCustom(ISD::MULHU, VT))
2826 Q = DAG.getNode(ISD::MULHU, dl, VT, Q, DAG.getConstant(magics.m, dl, VT));
2827 else if (IsAfterLegalization ? isOperationLegal(ISD::UMUL_LOHI, VT) :
2828 isOperationLegalOrCustom(ISD::UMUL_LOHI, VT))
2829 Q = SDValue(DAG.getNode(ISD::UMUL_LOHI, dl, DAG.getVTList(VT, VT), Q,
2830 DAG.getConstant(magics.m, dl, VT)).getNode(), 1);
2832 return SDValue(); // No mulhu or equvialent
2834 Created->push_back(Q.getNode());
2836 if (magics.a == 0) {
2837 assert(magics.s < Divisor.getBitWidth() &&
2838 "We shouldn't generate an undefined shift!");
2840 ISD::SRL, dl, VT, Q,
2841 DAG.getConstant(magics.s, dl, getShiftAmountTy(Q.getValueType(), DL)));
2843 SDValue NPQ = DAG.getNode(ISD::SUB, dl, VT, N->getOperand(0), Q);
2844 Created->push_back(NPQ.getNode());
2846 ISD::SRL, dl, VT, NPQ,
2847 DAG.getConstant(1, dl, getShiftAmountTy(NPQ.getValueType(), DL)));
2848 Created->push_back(NPQ.getNode());
2849 NPQ = DAG.getNode(ISD::ADD, dl, VT, NPQ, Q);
2850 Created->push_back(NPQ.getNode());
2852 ISD::SRL, dl, VT, NPQ,
2853 DAG.getConstant(magics.s - 1, dl,
2854 getShiftAmountTy(NPQ.getValueType(), DL)));
2858 bool TargetLowering::
2859 verifyReturnAddressArgumentIsConstant(SDValue Op, SelectionDAG &DAG) const {
2860 if (!isa<ConstantSDNode>(Op.getOperand(0))) {
2861 DAG.getContext()->emitError("argument to '__builtin_return_address' must "
2862 "be a constant integer");
2869 //===----------------------------------------------------------------------===//
2870 // Legalization Utilities
2871 //===----------------------------------------------------------------------===//
2873 bool TargetLowering::expandMUL(SDNode *N, SDValue &Lo, SDValue &Hi, EVT HiLoVT,
2874 SelectionDAG &DAG, SDValue LL, SDValue LH,
2875 SDValue RL, SDValue RH) const {
2876 EVT VT = N->getValueType(0);
2879 bool HasMULHS = isOperationLegalOrCustom(ISD::MULHS, HiLoVT);
2880 bool HasMULHU = isOperationLegalOrCustom(ISD::MULHU, HiLoVT);
2881 bool HasSMUL_LOHI = isOperationLegalOrCustom(ISD::SMUL_LOHI, HiLoVT);
2882 bool HasUMUL_LOHI = isOperationLegalOrCustom(ISD::UMUL_LOHI, HiLoVT);
2883 if (HasMULHU || HasMULHS || HasUMUL_LOHI || HasSMUL_LOHI) {
2884 unsigned OuterBitSize = VT.getSizeInBits();
2885 unsigned InnerBitSize = HiLoVT.getSizeInBits();
2886 unsigned LHSSB = DAG.ComputeNumSignBits(N->getOperand(0));
2887 unsigned RHSSB = DAG.ComputeNumSignBits(N->getOperand(1));
2889 // LL, LH, RL, and RH must be either all NULL or all set to a value.
2890 assert((LL.getNode() && LH.getNode() && RL.getNode() && RH.getNode()) ||
2891 (!LL.getNode() && !LH.getNode() && !RL.getNode() && !RH.getNode()));
2893 if (!LL.getNode() && !RL.getNode() &&
2894 isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
2895 LL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, N->getOperand(0));
2896 RL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, N->getOperand(1));
2902 APInt HighMask = APInt::getHighBitsSet(OuterBitSize, InnerBitSize);
2903 if (DAG.MaskedValueIsZero(N->getOperand(0), HighMask) &&
2904 DAG.MaskedValueIsZero(N->getOperand(1), HighMask)) {
2905 // The inputs are both zero-extended.
2907 // We can emit a umul_lohi.
2908 Lo = DAG.getNode(ISD::UMUL_LOHI, dl, DAG.getVTList(HiLoVT, HiLoVT), LL,
2910 Hi = SDValue(Lo.getNode(), 1);
2914 // We can emit a mulhu+mul.
2915 Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RL);
2916 Hi = DAG.getNode(ISD::MULHU, dl, HiLoVT, LL, RL);
2920 if (LHSSB > InnerBitSize && RHSSB > InnerBitSize) {
2921 // The input values are both sign-extended.
2923 // We can emit a smul_lohi.
2924 Lo = DAG.getNode(ISD::SMUL_LOHI, dl, DAG.getVTList(HiLoVT, HiLoVT), LL,
2926 Hi = SDValue(Lo.getNode(), 1);
2930 // We can emit a mulhs+mul.
2931 Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RL);
2932 Hi = DAG.getNode(ISD::MULHS, dl, HiLoVT, LL, RL);
2937 if (!LH.getNode() && !RH.getNode() &&
2938 isOperationLegalOrCustom(ISD::SRL, VT) &&
2939 isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
2940 auto &DL = DAG.getDataLayout();
2941 unsigned ShiftAmt = VT.getSizeInBits() - HiLoVT.getSizeInBits();
2942 SDValue Shift = DAG.getConstant(ShiftAmt, dl, getShiftAmountTy(VT, DL));
2943 LH = DAG.getNode(ISD::SRL, dl, VT, N->getOperand(0), Shift);
2944 LH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, LH);
2945 RH = DAG.getNode(ISD::SRL, dl, VT, N->getOperand(1), Shift);
2946 RH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, RH);
2953 // Lo,Hi = umul LHS, RHS.
2954 SDValue UMulLOHI = DAG.getNode(ISD::UMUL_LOHI, dl,
2955 DAG.getVTList(HiLoVT, HiLoVT), LL, RL);
2957 Hi = UMulLOHI.getValue(1);
2958 RH = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RH);
2959 LH = DAG.getNode(ISD::MUL, dl, HiLoVT, LH, RL);
2960 Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, RH);
2961 Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, LH);
2965 Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RL);
2966 Hi = DAG.getNode(ISD::MULHU, dl, HiLoVT, LL, RL);
2967 RH = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RH);
2968 LH = DAG.getNode(ISD::MUL, dl, HiLoVT, LH, RL);
2969 Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, RH);
2970 Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, LH);
2977 bool TargetLowering::expandFP_TO_SINT(SDNode *Node, SDValue &Result,
2978 SelectionDAG &DAG) const {
2979 EVT VT = Node->getOperand(0).getValueType();
2980 EVT NVT = Node->getValueType(0);
2981 SDLoc dl(SDValue(Node, 0));
2983 // FIXME: Only f32 to i64 conversions are supported.
2984 if (VT != MVT::f32 || NVT != MVT::i64)
2987 // Expand f32 -> i64 conversion
2988 // This algorithm comes from compiler-rt's implementation of fixsfdi:
2989 // https://github.com/llvm-mirror/compiler-rt/blob/master/lib/builtins/fixsfdi.c
2990 EVT IntVT = EVT::getIntegerVT(*DAG.getContext(),
2991 VT.getSizeInBits());
2992 SDValue ExponentMask = DAG.getConstant(0x7F800000, dl, IntVT);
2993 SDValue ExponentLoBit = DAG.getConstant(23, dl, IntVT);
2994 SDValue Bias = DAG.getConstant(127, dl, IntVT);
2995 SDValue SignMask = DAG.getConstant(APInt::getSignBit(VT.getSizeInBits()), dl,
2997 SDValue SignLowBit = DAG.getConstant(VT.getSizeInBits() - 1, dl, IntVT);
2998 SDValue MantissaMask = DAG.getConstant(0x007FFFFF, dl, IntVT);
3000 SDValue Bits = DAG.getNode(ISD::BITCAST, dl, IntVT, Node->getOperand(0));
3002 auto &DL = DAG.getDataLayout();
3003 SDValue ExponentBits = DAG.getNode(
3004 ISD::SRL, dl, IntVT, DAG.getNode(ISD::AND, dl, IntVT, Bits, ExponentMask),
3005 DAG.getZExtOrTrunc(ExponentLoBit, dl, getShiftAmountTy(IntVT, DL)));
3006 SDValue Exponent = DAG.getNode(ISD::SUB, dl, IntVT, ExponentBits, Bias);
3008 SDValue Sign = DAG.getNode(
3009 ISD::SRA, dl, IntVT, DAG.getNode(ISD::AND, dl, IntVT, Bits, SignMask),
3010 DAG.getZExtOrTrunc(SignLowBit, dl, getShiftAmountTy(IntVT, DL)));
3011 Sign = DAG.getSExtOrTrunc(Sign, dl, NVT);
3013 SDValue R = DAG.getNode(ISD::OR, dl, IntVT,
3014 DAG.getNode(ISD::AND, dl, IntVT, Bits, MantissaMask),
3015 DAG.getConstant(0x00800000, dl, IntVT));
3017 R = DAG.getZExtOrTrunc(R, dl, NVT);
3019 R = DAG.getSelectCC(
3020 dl, Exponent, ExponentLoBit,
3021 DAG.getNode(ISD::SHL, dl, NVT, R,
3023 DAG.getNode(ISD::SUB, dl, IntVT, Exponent, ExponentLoBit),
3024 dl, getShiftAmountTy(IntVT, DL))),
3025 DAG.getNode(ISD::SRL, dl, NVT, R,
3027 DAG.getNode(ISD::SUB, dl, IntVT, ExponentLoBit, Exponent),
3028 dl, getShiftAmountTy(IntVT, DL))),
3031 SDValue Ret = DAG.getNode(ISD::SUB, dl, NVT,
3032 DAG.getNode(ISD::XOR, dl, NVT, R, Sign),
3035 Result = DAG.getSelectCC(dl, Exponent, DAG.getConstant(0, dl, IntVT),
3036 DAG.getConstant(0, dl, NVT), Ret, ISD::SETLT);