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/MC/MCAsmInfo.h"
26 #include "llvm/MC/MCExpr.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/MathExtras.h"
30 #include "llvm/Target/TargetLoweringObjectFile.h"
31 #include "llvm/Target/TargetMachine.h"
32 #include "llvm/Target/TargetRegisterInfo.h"
36 /// NOTE: The constructor takes ownership of TLOF.
37 TargetLowering::TargetLowering(const TargetMachine &tm,
38 const TargetLoweringObjectFile *tlof)
39 : TargetLoweringBase(tm, tlof) {}
41 const char *TargetLowering::getTargetNodeName(unsigned Opcode) const {
45 /// Check whether a given call node is in tail position within its function. If
46 /// so, it sets Chain to the input chain of the tail call.
47 bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
48 SDValue &Chain) const {
49 const Function *F = DAG.getMachineFunction().getFunction();
51 // Conservatively require the attributes of the call to match those of
52 // the return. Ignore noalias because it doesn't affect the call sequence.
53 AttributeSet CallerAttrs = F->getAttributes();
54 if (AttrBuilder(CallerAttrs, AttributeSet::ReturnIndex)
55 .removeAttribute(Attribute::NoAlias).hasAttributes())
58 // It's not safe to eliminate the sign / zero extension of the return value.
59 if (CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::ZExt) ||
60 CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::SExt))
63 // Check if the only use is a function return node.
64 return isUsedByReturnOnly(Node, Chain);
68 /// Generate a libcall taking the given operands as arguments and returning a
69 /// result of type RetVT.
70 std::pair<SDValue, SDValue>
71 TargetLowering::makeLibCall(SelectionDAG &DAG,
72 RTLIB::Libcall LC, EVT RetVT,
73 const SDValue *Ops, unsigned NumOps,
74 bool isSigned, SDLoc dl,
76 bool isReturnValueUsed) const {
77 TargetLowering::ArgListTy Args;
80 TargetLowering::ArgListEntry Entry;
81 for (unsigned i = 0; i != NumOps; ++i) {
83 Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext());
84 Entry.isSExt = isSigned;
85 Entry.isZExt = !isSigned;
86 Args.push_back(Entry);
88 SDValue Callee = DAG.getExternalSymbol(getLibcallName(LC), getPointerTy());
90 Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext());
92 CallLoweringInfo CLI(DAG.getEntryNode(), RetTy, isSigned, !isSigned, false,
93 false, 0, getLibcallCallingConv(LC),
95 doesNotReturn, isReturnValueUsed, Callee, Args,
97 return LowerCallTo(CLI);
101 /// SoftenSetCCOperands - Soften the operands of a comparison. This code is
102 /// shared among BR_CC, SELECT_CC, and SETCC handlers.
103 void TargetLowering::softenSetCCOperands(SelectionDAG &DAG, EVT VT,
104 SDValue &NewLHS, SDValue &NewRHS,
105 ISD::CondCode &CCCode,
107 assert((VT == MVT::f32 || VT == MVT::f64 || VT == MVT::f128)
108 && "Unsupported setcc type!");
110 // Expand into one or more soft-fp libcall(s).
111 RTLIB::Libcall LC1 = RTLIB::UNKNOWN_LIBCALL, LC2 = RTLIB::UNKNOWN_LIBCALL;
115 LC1 = (VT == MVT::f32) ? RTLIB::OEQ_F32 :
116 (VT == MVT::f64) ? RTLIB::OEQ_F64 : RTLIB::OEQ_F128;
120 LC1 = (VT == MVT::f32) ? RTLIB::UNE_F32 :
121 (VT == MVT::f64) ? RTLIB::UNE_F64 : RTLIB::UNE_F128;
125 LC1 = (VT == MVT::f32) ? RTLIB::OGE_F32 :
126 (VT == MVT::f64) ? RTLIB::OGE_F64 : RTLIB::OGE_F128;
130 LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
131 (VT == MVT::f64) ? RTLIB::OLT_F64 : RTLIB::OLT_F128;
135 LC1 = (VT == MVT::f32) ? RTLIB::OLE_F32 :
136 (VT == MVT::f64) ? RTLIB::OLE_F64 : RTLIB::OLE_F128;
140 LC1 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
141 (VT == MVT::f64) ? RTLIB::OGT_F64 : RTLIB::OGT_F128;
144 LC1 = (VT == MVT::f32) ? RTLIB::UO_F32 :
145 (VT == MVT::f64) ? RTLIB::UO_F64 : RTLIB::UO_F128;
148 LC1 = (VT == MVT::f32) ? RTLIB::O_F32 :
149 (VT == MVT::f64) ? RTLIB::O_F64 : RTLIB::O_F128;
152 LC1 = (VT == MVT::f32) ? RTLIB::UO_F32 :
153 (VT == MVT::f64) ? RTLIB::UO_F64 : RTLIB::UO_F128;
156 // SETONE = SETOLT | SETOGT
157 LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
158 (VT == MVT::f64) ? RTLIB::OLT_F64 : RTLIB::OLT_F128;
161 LC2 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
162 (VT == MVT::f64) ? RTLIB::OGT_F64 : RTLIB::OGT_F128;
165 LC2 = (VT == MVT::f32) ? RTLIB::OGE_F32 :
166 (VT == MVT::f64) ? RTLIB::OGE_F64 : RTLIB::OGE_F128;
169 LC2 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
170 (VT == MVT::f64) ? RTLIB::OLT_F64 : RTLIB::OLT_F128;
173 LC2 = (VT == MVT::f32) ? RTLIB::OLE_F32 :
174 (VT == MVT::f64) ? RTLIB::OLE_F64 : RTLIB::OLE_F128;
177 LC2 = (VT == MVT::f32) ? RTLIB::OEQ_F32 :
178 (VT == MVT::f64) ? RTLIB::OEQ_F64 : RTLIB::OEQ_F128;
180 default: llvm_unreachable("Do not know how to soften this setcc!");
184 // Use the target specific return value for comparions lib calls.
185 EVT RetVT = getCmpLibcallReturnType();
186 SDValue Ops[2] = { NewLHS, NewRHS };
187 NewLHS = makeLibCall(DAG, LC1, RetVT, Ops, 2, false/*sign irrelevant*/,
189 NewRHS = DAG.getConstant(0, RetVT);
190 CCCode = getCmpLibcallCC(LC1);
191 if (LC2 != RTLIB::UNKNOWN_LIBCALL) {
192 SDValue Tmp = DAG.getNode(ISD::SETCC, dl,
193 getSetCCResultType(*DAG.getContext(), RetVT),
194 NewLHS, NewRHS, DAG.getCondCode(CCCode));
195 NewLHS = makeLibCall(DAG, LC2, RetVT, Ops, 2, false/*sign irrelevant*/,
197 NewLHS = DAG.getNode(ISD::SETCC, dl,
198 getSetCCResultType(*DAG.getContext(), RetVT), NewLHS,
199 NewRHS, DAG.getCondCode(getCmpLibcallCC(LC2)));
200 NewLHS = DAG.getNode(ISD::OR, dl, Tmp.getValueType(), Tmp, NewLHS);
205 /// getJumpTableEncoding - Return the entry encoding for a jump table in the
206 /// current function. The returned value is a member of the
207 /// MachineJumpTableInfo::JTEntryKind enum.
208 unsigned TargetLowering::getJumpTableEncoding() const {
209 // In non-pic modes, just use the address of a block.
210 if (getTargetMachine().getRelocationModel() != Reloc::PIC_)
211 return MachineJumpTableInfo::EK_BlockAddress;
213 // In PIC mode, if the target supports a GPRel32 directive, use it.
214 if (getTargetMachine().getMCAsmInfo()->getGPRel32Directive() != 0)
215 return MachineJumpTableInfo::EK_GPRel32BlockAddress;
217 // Otherwise, use a label difference.
218 return MachineJumpTableInfo::EK_LabelDifference32;
221 SDValue TargetLowering::getPICJumpTableRelocBase(SDValue Table,
222 SelectionDAG &DAG) const {
223 // If our PIC model is GP relative, use the global offset table as the base.
224 unsigned JTEncoding = getJumpTableEncoding();
226 if ((JTEncoding == MachineJumpTableInfo::EK_GPRel64BlockAddress) ||
227 (JTEncoding == MachineJumpTableInfo::EK_GPRel32BlockAddress))
228 return DAG.getGLOBAL_OFFSET_TABLE(getPointerTy(0));
233 /// getPICJumpTableRelocBaseExpr - This returns the relocation base for the
234 /// given PIC jumptable, the same as getPICJumpTableRelocBase, but as an
237 TargetLowering::getPICJumpTableRelocBaseExpr(const MachineFunction *MF,
238 unsigned JTI,MCContext &Ctx) const{
239 // The normal PIC reloc base is the label at the start of the jump table.
240 return MCSymbolRefExpr::Create(MF->getJTISymbol(JTI, Ctx), Ctx);
244 TargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
245 // Assume that everything is safe in static mode.
246 if (getTargetMachine().getRelocationModel() == Reloc::Static)
249 // In dynamic-no-pic mode, assume that known defined values are safe.
250 if (getTargetMachine().getRelocationModel() == Reloc::DynamicNoPIC &&
252 !GA->getGlobal()->isDeclaration() &&
253 !GA->getGlobal()->isWeakForLinker())
256 // Otherwise assume nothing is safe.
260 //===----------------------------------------------------------------------===//
261 // Optimization Methods
262 //===----------------------------------------------------------------------===//
264 /// ShrinkDemandedConstant - Check to see if the specified operand of the
265 /// specified instruction is a constant integer. If so, check to see if there
266 /// are any bits set in the constant that are not demanded. If so, shrink the
267 /// constant and return true.
268 bool TargetLowering::TargetLoweringOpt::ShrinkDemandedConstant(SDValue Op,
269 const APInt &Demanded) {
272 // FIXME: ISD::SELECT, ISD::SELECT_CC
273 switch (Op.getOpcode()) {
278 ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
279 if (!C) return false;
281 if (Op.getOpcode() == ISD::XOR &&
282 (C->getAPIntValue() | (~Demanded)).isAllOnesValue())
285 // if we can expand it to have all bits set, do it
286 if (C->getAPIntValue().intersects(~Demanded)) {
287 EVT VT = Op.getValueType();
288 SDValue New = DAG.getNode(Op.getOpcode(), dl, VT, Op.getOperand(0),
289 DAG.getConstant(Demanded &
292 return CombineTo(Op, New);
302 /// ShrinkDemandedOp - Convert x+y to (VT)((SmallVT)x+(SmallVT)y) if the
303 /// casts are free. This uses isZExtFree and ZERO_EXTEND for the widening
304 /// cast, but it could be generalized for targets with other types of
305 /// implicit widening casts.
307 TargetLowering::TargetLoweringOpt::ShrinkDemandedOp(SDValue Op,
309 const APInt &Demanded,
311 assert(Op.getNumOperands() == 2 &&
312 "ShrinkDemandedOp only supports binary operators!");
313 assert(Op.getNode()->getNumValues() == 1 &&
314 "ShrinkDemandedOp only supports nodes with one result!");
316 // Don't do this if the node has another user, which may require the
318 if (!Op.getNode()->hasOneUse())
321 // Search for the smallest integer type with free casts to and from
322 // Op's type. For expedience, just check power-of-2 integer types.
323 const TargetLowering &TLI = DAG.getTargetLoweringInfo();
324 unsigned DemandedSize = BitWidth - Demanded.countLeadingZeros();
325 unsigned SmallVTBits = DemandedSize;
326 if (!isPowerOf2_32(SmallVTBits))
327 SmallVTBits = NextPowerOf2(SmallVTBits);
328 for (; SmallVTBits < BitWidth; SmallVTBits = NextPowerOf2(SmallVTBits)) {
329 EVT SmallVT = EVT::getIntegerVT(*DAG.getContext(), SmallVTBits);
330 if (TLI.isTruncateFree(Op.getValueType(), SmallVT) &&
331 TLI.isZExtFree(SmallVT, Op.getValueType())) {
332 // We found a type with free casts.
333 SDValue X = DAG.getNode(Op.getOpcode(), dl, SmallVT,
334 DAG.getNode(ISD::TRUNCATE, dl, SmallVT,
335 Op.getNode()->getOperand(0)),
336 DAG.getNode(ISD::TRUNCATE, dl, SmallVT,
337 Op.getNode()->getOperand(1)));
338 bool NeedZext = DemandedSize > SmallVTBits;
339 SDValue Z = DAG.getNode(NeedZext ? ISD::ZERO_EXTEND : ISD::ANY_EXTEND,
340 dl, Op.getValueType(), X);
341 return CombineTo(Op, Z);
347 /// SimplifyDemandedBits - Look at Op. At this point, we know that only the
348 /// DemandedMask bits of the result of Op are ever used downstream. If we can
349 /// use this information to simplify Op, create a new simplified DAG node and
350 /// return true, returning the original and new nodes in Old and New. Otherwise,
351 /// analyze the expression and return a mask of KnownOne and KnownZero bits for
352 /// the expression (used to simplify the caller). The KnownZero/One bits may
353 /// only be accurate for those bits in the DemandedMask.
354 bool TargetLowering::SimplifyDemandedBits(SDValue Op,
355 const APInt &DemandedMask,
358 TargetLoweringOpt &TLO,
359 unsigned Depth) const {
360 unsigned BitWidth = DemandedMask.getBitWidth();
361 assert(Op.getValueType().getScalarType().getSizeInBits() == BitWidth &&
362 "Mask size mismatches value type size!");
363 APInt NewMask = DemandedMask;
366 // Don't know anything.
367 KnownZero = KnownOne = APInt(BitWidth, 0);
369 // Other users may use these bits.
370 if (!Op.getNode()->hasOneUse()) {
372 // If not at the root, Just compute the KnownZero/KnownOne bits to
373 // simplify things downstream.
374 TLO.DAG.ComputeMaskedBits(Op, KnownZero, KnownOne, Depth);
377 // If this is the root being simplified, allow it to have multiple uses,
378 // just set the NewMask to all bits.
379 NewMask = APInt::getAllOnesValue(BitWidth);
380 } else if (DemandedMask == 0) {
381 // Not demanding any bits from Op.
382 if (Op.getOpcode() != ISD::UNDEF)
383 return TLO.CombineTo(Op, TLO.DAG.getUNDEF(Op.getValueType()));
385 } else if (Depth == 6) { // Limit search depth.
389 APInt KnownZero2, KnownOne2, KnownZeroOut, KnownOneOut;
390 switch (Op.getOpcode()) {
392 // We know all of the bits for a constant!
393 KnownOne = cast<ConstantSDNode>(Op)->getAPIntValue();
394 KnownZero = ~KnownOne;
395 return false; // Don't fall through, will infinitely loop.
397 // If the RHS is a constant, check to see if the LHS would be zero without
398 // using the bits from the RHS. Below, we use knowledge about the RHS to
399 // simplify the LHS, here we're using information from the LHS to simplify
401 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
402 APInt LHSZero, LHSOne;
403 // Do not increment Depth here; that can cause an infinite loop.
404 TLO.DAG.ComputeMaskedBits(Op.getOperand(0), LHSZero, LHSOne, Depth);
405 // If the LHS already has zeros where RHSC does, this and is dead.
406 if ((LHSZero & NewMask) == (~RHSC->getAPIntValue() & NewMask))
407 return TLO.CombineTo(Op, Op.getOperand(0));
408 // If any of the set bits in the RHS are known zero on the LHS, shrink
410 if (TLO.ShrinkDemandedConstant(Op, ~LHSZero & NewMask))
414 if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
415 KnownOne, TLO, Depth+1))
417 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
418 if (SimplifyDemandedBits(Op.getOperand(0), ~KnownZero & NewMask,
419 KnownZero2, KnownOne2, TLO, Depth+1))
421 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
423 // If all of the demanded bits are known one on one side, return the other.
424 // These bits cannot contribute to the result of the 'and'.
425 if ((NewMask & ~KnownZero2 & KnownOne) == (~KnownZero2 & NewMask))
426 return TLO.CombineTo(Op, Op.getOperand(0));
427 if ((NewMask & ~KnownZero & KnownOne2) == (~KnownZero & NewMask))
428 return TLO.CombineTo(Op, Op.getOperand(1));
429 // If all of the demanded bits in the inputs are known zeros, return zero.
430 if ((NewMask & (KnownZero|KnownZero2)) == NewMask)
431 return TLO.CombineTo(Op, TLO.DAG.getConstant(0, Op.getValueType()));
432 // If the RHS is a constant, see if we can simplify it.
433 if (TLO.ShrinkDemandedConstant(Op, ~KnownZero2 & NewMask))
435 // If the operation can be done in a smaller type, do so.
436 if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
439 // Output known-1 bits are only known if set in both the LHS & RHS.
440 KnownOne &= KnownOne2;
441 // Output known-0 are known to be clear if zero in either the LHS | RHS.
442 KnownZero |= KnownZero2;
445 if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
446 KnownOne, TLO, Depth+1))
448 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
449 if (SimplifyDemandedBits(Op.getOperand(0), ~KnownOne & NewMask,
450 KnownZero2, KnownOne2, TLO, Depth+1))
452 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
454 // If all of the demanded bits are known zero on one side, return the other.
455 // These bits cannot contribute to the result of the 'or'.
456 if ((NewMask & ~KnownOne2 & KnownZero) == (~KnownOne2 & NewMask))
457 return TLO.CombineTo(Op, Op.getOperand(0));
458 if ((NewMask & ~KnownOne & KnownZero2) == (~KnownOne & NewMask))
459 return TLO.CombineTo(Op, Op.getOperand(1));
460 // If all of the potentially set bits on one side are known to be set on
461 // the other side, just use the 'other' side.
462 if ((NewMask & ~KnownZero & KnownOne2) == (~KnownZero & NewMask))
463 return TLO.CombineTo(Op, Op.getOperand(0));
464 if ((NewMask & ~KnownZero2 & KnownOne) == (~KnownZero2 & NewMask))
465 return TLO.CombineTo(Op, Op.getOperand(1));
466 // If the RHS is a constant, see if we can simplify it.
467 if (TLO.ShrinkDemandedConstant(Op, NewMask))
469 // If the operation can be done in a smaller type, do so.
470 if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
473 // Output known-0 bits are only known if clear in both the LHS & RHS.
474 KnownZero &= KnownZero2;
475 // Output known-1 are known to be set if set in either the LHS | RHS.
476 KnownOne |= KnownOne2;
479 if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
480 KnownOne, TLO, Depth+1))
482 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
483 if (SimplifyDemandedBits(Op.getOperand(0), NewMask, KnownZero2,
484 KnownOne2, TLO, Depth+1))
486 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
488 // If all of the demanded bits are known zero on one side, return the other.
489 // These bits cannot contribute to the result of the 'xor'.
490 if ((KnownZero & NewMask) == NewMask)
491 return TLO.CombineTo(Op, Op.getOperand(0));
492 if ((KnownZero2 & NewMask) == NewMask)
493 return TLO.CombineTo(Op, Op.getOperand(1));
494 // If the operation can be done in a smaller type, do so.
495 if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
498 // If all of the unknown bits are known to be zero on one side or the other
499 // (but not both) turn this into an *inclusive* or.
500 // e.g. (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1&C2 == 0
501 if ((NewMask & ~KnownZero & ~KnownZero2) == 0)
502 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::OR, dl, Op.getValueType(),
506 // Output known-0 bits are known if clear or set in both the LHS & RHS.
507 KnownZeroOut = (KnownZero & KnownZero2) | (KnownOne & KnownOne2);
508 // Output known-1 are known to be set if set in only one of the LHS, RHS.
509 KnownOneOut = (KnownZero & KnownOne2) | (KnownOne & KnownZero2);
511 // If all of the demanded bits on one side are known, and all of the set
512 // bits on that side are also known to be set on the other side, turn this
513 // into an AND, as we know the bits will be cleared.
514 // e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2
515 // NB: it is okay if more bits are known than are requested
516 if ((NewMask & (KnownZero|KnownOne)) == NewMask) { // all known on one side
517 if (KnownOne == KnownOne2) { // set bits are the same on both sides
518 EVT VT = Op.getValueType();
519 SDValue ANDC = TLO.DAG.getConstant(~KnownOne & NewMask, VT);
520 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::AND, dl, VT,
521 Op.getOperand(0), ANDC));
525 // If the RHS is a constant, see if we can simplify it.
526 // for XOR, we prefer to force bits to 1 if they will make a -1.
527 // if we can't force bits, try to shrink constant
528 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
529 APInt Expanded = C->getAPIntValue() | (~NewMask);
530 // if we can expand it to have all bits set, do it
531 if (Expanded.isAllOnesValue()) {
532 if (Expanded != C->getAPIntValue()) {
533 EVT VT = Op.getValueType();
534 SDValue New = TLO.DAG.getNode(Op.getOpcode(), dl,VT, Op.getOperand(0),
535 TLO.DAG.getConstant(Expanded, VT));
536 return TLO.CombineTo(Op, New);
538 // if it already has all the bits set, nothing to change
539 // but don't shrink either!
540 } else if (TLO.ShrinkDemandedConstant(Op, NewMask)) {
545 KnownZero = KnownZeroOut;
546 KnownOne = KnownOneOut;
549 if (SimplifyDemandedBits(Op.getOperand(2), NewMask, KnownZero,
550 KnownOne, TLO, Depth+1))
552 if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero2,
553 KnownOne2, TLO, Depth+1))
555 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
556 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
558 // If the operands are constants, see if we can simplify them.
559 if (TLO.ShrinkDemandedConstant(Op, NewMask))
562 // Only known if known in both the LHS and RHS.
563 KnownOne &= KnownOne2;
564 KnownZero &= KnownZero2;
567 if (SimplifyDemandedBits(Op.getOperand(3), NewMask, KnownZero,
568 KnownOne, TLO, Depth+1))
570 if (SimplifyDemandedBits(Op.getOperand(2), NewMask, KnownZero2,
571 KnownOne2, TLO, Depth+1))
573 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
574 assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
576 // If the operands are constants, see if we can simplify them.
577 if (TLO.ShrinkDemandedConstant(Op, NewMask))
580 // Only known if known in both the LHS and RHS.
581 KnownOne &= KnownOne2;
582 KnownZero &= KnownZero2;
585 if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
586 unsigned ShAmt = SA->getZExtValue();
587 SDValue InOp = Op.getOperand(0);
589 // If the shift count is an invalid immediate, don't do anything.
590 if (ShAmt >= BitWidth)
593 // If this is ((X >>u C1) << ShAmt), see if we can simplify this into a
594 // single shift. We can do this if the bottom bits (which are shifted
595 // out) are never demanded.
596 if (InOp.getOpcode() == ISD::SRL &&
597 isa<ConstantSDNode>(InOp.getOperand(1))) {
598 if (ShAmt && (NewMask & APInt::getLowBitsSet(BitWidth, ShAmt)) == 0) {
599 unsigned C1= cast<ConstantSDNode>(InOp.getOperand(1))->getZExtValue();
600 unsigned Opc = ISD::SHL;
608 TLO.DAG.getConstant(Diff, Op.getOperand(1).getValueType());
609 EVT VT = Op.getValueType();
610 return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT,
611 InOp.getOperand(0), NewSA));
615 if (SimplifyDemandedBits(InOp, NewMask.lshr(ShAmt),
616 KnownZero, KnownOne, TLO, Depth+1))
619 // Convert (shl (anyext x, c)) to (anyext (shl x, c)) if the high bits
620 // are not demanded. This will likely allow the anyext to be folded away.
621 if (InOp.getNode()->getOpcode() == ISD::ANY_EXTEND) {
622 SDValue InnerOp = InOp.getNode()->getOperand(0);
623 EVT InnerVT = InnerOp.getValueType();
624 unsigned InnerBits = InnerVT.getSizeInBits();
625 if (ShAmt < InnerBits && NewMask.lshr(InnerBits) == 0 &&
626 isTypeDesirableForOp(ISD::SHL, InnerVT)) {
627 EVT ShTy = getShiftAmountTy(InnerVT);
628 if (!APInt(BitWidth, ShAmt).isIntN(ShTy.getSizeInBits()))
631 TLO.DAG.getNode(ISD::SHL, dl, InnerVT, InnerOp,
632 TLO.DAG.getConstant(ShAmt, ShTy));
635 TLO.DAG.getNode(ISD::ANY_EXTEND, dl, Op.getValueType(),
638 // Repeat the SHL optimization above in cases where an extension
639 // intervenes: (shl (anyext (shr x, c1)), c2) to
640 // (shl (anyext x), c2-c1). This requires that the bottom c1 bits
641 // aren't demanded (as above) and that the shifted upper c1 bits of
642 // x aren't demanded.
643 if (InOp.hasOneUse() &&
644 InnerOp.getOpcode() == ISD::SRL &&
645 InnerOp.hasOneUse() &&
646 isa<ConstantSDNode>(InnerOp.getOperand(1))) {
647 uint64_t InnerShAmt = cast<ConstantSDNode>(InnerOp.getOperand(1))
649 if (InnerShAmt < ShAmt &&
650 InnerShAmt < InnerBits &&
651 NewMask.lshr(InnerBits - InnerShAmt + ShAmt) == 0 &&
652 NewMask.trunc(ShAmt) == 0) {
654 TLO.DAG.getConstant(ShAmt - InnerShAmt,
655 Op.getOperand(1).getValueType());
656 EVT VT = Op.getValueType();
657 SDValue NewExt = TLO.DAG.getNode(ISD::ANY_EXTEND, dl, VT,
658 InnerOp.getOperand(0));
659 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl, VT,
665 KnownZero <<= SA->getZExtValue();
666 KnownOne <<= SA->getZExtValue();
667 // low bits known zero.
668 KnownZero |= APInt::getLowBitsSet(BitWidth, SA->getZExtValue());
672 if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
673 EVT VT = Op.getValueType();
674 unsigned ShAmt = SA->getZExtValue();
675 unsigned VTSize = VT.getSizeInBits();
676 SDValue InOp = Op.getOperand(0);
678 // If the shift count is an invalid immediate, don't do anything.
679 if (ShAmt >= BitWidth)
682 // If this is ((X << C1) >>u ShAmt), see if we can simplify this into a
683 // single shift. We can do this if the top bits (which are shifted out)
684 // are never demanded.
685 if (InOp.getOpcode() == ISD::SHL &&
686 isa<ConstantSDNode>(InOp.getOperand(1))) {
687 if (ShAmt && (NewMask & APInt::getHighBitsSet(VTSize, ShAmt)) == 0) {
688 unsigned C1= cast<ConstantSDNode>(InOp.getOperand(1))->getZExtValue();
689 unsigned Opc = ISD::SRL;
697 TLO.DAG.getConstant(Diff, Op.getOperand(1).getValueType());
698 return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT,
699 InOp.getOperand(0), NewSA));
703 // Compute the new bits that are at the top now.
704 if (SimplifyDemandedBits(InOp, (NewMask << ShAmt),
705 KnownZero, KnownOne, TLO, Depth+1))
707 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
708 KnownZero = KnownZero.lshr(ShAmt);
709 KnownOne = KnownOne.lshr(ShAmt);
711 APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
712 KnownZero |= HighBits; // High bits known zero.
716 // If this is an arithmetic shift right and only the low-bit is set, we can
717 // always convert this into a logical shr, even if the shift amount is
718 // variable. The low bit of the shift cannot be an input sign bit unless
719 // the shift amount is >= the size of the datatype, which is undefined.
721 return TLO.CombineTo(Op,
722 TLO.DAG.getNode(ISD::SRL, dl, Op.getValueType(),
723 Op.getOperand(0), Op.getOperand(1)));
725 if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
726 EVT VT = Op.getValueType();
727 unsigned ShAmt = SA->getZExtValue();
729 // If the shift count is an invalid immediate, don't do anything.
730 if (ShAmt >= BitWidth)
733 APInt InDemandedMask = (NewMask << ShAmt);
735 // If any of the demanded bits are produced by the sign extension, we also
736 // demand the input sign bit.
737 APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
738 if (HighBits.intersects(NewMask))
739 InDemandedMask |= APInt::getSignBit(VT.getScalarType().getSizeInBits());
741 if (SimplifyDemandedBits(Op.getOperand(0), InDemandedMask,
742 KnownZero, KnownOne, TLO, Depth+1))
744 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
745 KnownZero = KnownZero.lshr(ShAmt);
746 KnownOne = KnownOne.lshr(ShAmt);
748 // Handle the sign bit, adjusted to where it is now in the mask.
749 APInt SignBit = APInt::getSignBit(BitWidth).lshr(ShAmt);
751 // If the input sign bit is known to be zero, or if none of the top bits
752 // are demanded, turn this into an unsigned shift right.
753 if (KnownZero.intersects(SignBit) || (HighBits & ~NewMask) == HighBits)
754 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl, VT,
758 int Log2 = NewMask.exactLogBase2();
760 // The bit must come from the sign.
762 TLO.DAG.getConstant(BitWidth - 1 - Log2,
763 Op.getOperand(1).getValueType());
764 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl, VT,
765 Op.getOperand(0), NewSA));
768 if (KnownOne.intersects(SignBit))
769 // New bits are known one.
770 KnownOne |= HighBits;
773 case ISD::SIGN_EXTEND_INREG: {
774 EVT ExVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
776 APInt MsbMask = APInt::getHighBitsSet(BitWidth, 1);
777 // If we only care about the highest bit, don't bother shifting right.
778 if (MsbMask == DemandedMask) {
779 unsigned ShAmt = ExVT.getScalarType().getSizeInBits();
780 SDValue InOp = Op.getOperand(0);
782 // Compute the correct shift amount type, which must be getShiftAmountTy
783 // for scalar types after legalization.
784 EVT ShiftAmtTy = Op.getValueType();
785 if (TLO.LegalTypes() && !ShiftAmtTy.isVector())
786 ShiftAmtTy = getShiftAmountTy(ShiftAmtTy);
788 SDValue ShiftAmt = TLO.DAG.getConstant(BitWidth - ShAmt, ShiftAmtTy);
789 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl,
790 Op.getValueType(), InOp, ShiftAmt));
793 // Sign extension. Compute the demanded bits in the result that are not
794 // present in the input.
796 APInt::getHighBitsSet(BitWidth,
797 BitWidth - ExVT.getScalarType().getSizeInBits());
799 // If none of the extended bits are demanded, eliminate the sextinreg.
800 if ((NewBits & NewMask) == 0)
801 return TLO.CombineTo(Op, Op.getOperand(0));
804 APInt::getSignBit(ExVT.getScalarType().getSizeInBits()).zext(BitWidth);
805 APInt InputDemandedBits =
806 APInt::getLowBitsSet(BitWidth,
807 ExVT.getScalarType().getSizeInBits()) &
810 // Since the sign extended bits are demanded, we know that the sign
812 InputDemandedBits |= InSignBit;
814 if (SimplifyDemandedBits(Op.getOperand(0), InputDemandedBits,
815 KnownZero, KnownOne, TLO, Depth+1))
817 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
819 // If the sign bit of the input is known set or clear, then we know the
820 // top bits of the result.
822 // If the input sign bit is known zero, convert this into a zero extension.
823 if (KnownZero.intersects(InSignBit))
824 return TLO.CombineTo(Op,
825 TLO.DAG.getZeroExtendInReg(Op.getOperand(0),dl,ExVT));
827 if (KnownOne.intersects(InSignBit)) { // Input sign bit known set
829 KnownZero &= ~NewBits;
830 } else { // Input sign bit unknown
831 KnownZero &= ~NewBits;
832 KnownOne &= ~NewBits;
836 case ISD::ZERO_EXTEND: {
837 unsigned OperandBitWidth =
838 Op.getOperand(0).getValueType().getScalarType().getSizeInBits();
839 APInt InMask = NewMask.trunc(OperandBitWidth);
841 // If none of the top bits are demanded, convert this into an any_extend.
843 APInt::getHighBitsSet(BitWidth, BitWidth - OperandBitWidth) & NewMask;
844 if (!NewBits.intersects(NewMask))
845 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ANY_EXTEND, dl,
849 if (SimplifyDemandedBits(Op.getOperand(0), InMask,
850 KnownZero, KnownOne, TLO, Depth+1))
852 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
853 KnownZero = KnownZero.zext(BitWidth);
854 KnownOne = KnownOne.zext(BitWidth);
855 KnownZero |= NewBits;
858 case ISD::SIGN_EXTEND: {
859 EVT InVT = Op.getOperand(0).getValueType();
860 unsigned InBits = InVT.getScalarType().getSizeInBits();
861 APInt InMask = APInt::getLowBitsSet(BitWidth, InBits);
862 APInt InSignBit = APInt::getBitsSet(BitWidth, InBits - 1, InBits);
863 APInt NewBits = ~InMask & NewMask;
865 // If none of the top bits are demanded, convert this into an any_extend.
867 return TLO.CombineTo(Op,TLO.DAG.getNode(ISD::ANY_EXTEND, dl,
871 // Since some of the sign extended bits are demanded, we know that the sign
873 APInt InDemandedBits = InMask & NewMask;
874 InDemandedBits |= InSignBit;
875 InDemandedBits = InDemandedBits.trunc(InBits);
877 if (SimplifyDemandedBits(Op.getOperand(0), InDemandedBits, KnownZero,
878 KnownOne, TLO, Depth+1))
880 KnownZero = KnownZero.zext(BitWidth);
881 KnownOne = KnownOne.zext(BitWidth);
883 // If the sign bit is known zero, convert this to a zero extend.
884 if (KnownZero.intersects(InSignBit))
885 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ZERO_EXTEND, dl,
889 // If the sign bit is known one, the top bits match.
890 if (KnownOne.intersects(InSignBit)) {
892 assert((KnownZero & NewBits) == 0);
893 } else { // Otherwise, top bits aren't known.
894 assert((KnownOne & NewBits) == 0);
895 assert((KnownZero & NewBits) == 0);
899 case ISD::ANY_EXTEND: {
900 unsigned OperandBitWidth =
901 Op.getOperand(0).getValueType().getScalarType().getSizeInBits();
902 APInt InMask = NewMask.trunc(OperandBitWidth);
903 if (SimplifyDemandedBits(Op.getOperand(0), InMask,
904 KnownZero, KnownOne, TLO, Depth+1))
906 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
907 KnownZero = KnownZero.zext(BitWidth);
908 KnownOne = KnownOne.zext(BitWidth);
911 case ISD::TRUNCATE: {
912 // Simplify the input, using demanded bit information, and compute the known
913 // zero/one bits live out.
914 unsigned OperandBitWidth =
915 Op.getOperand(0).getValueType().getScalarType().getSizeInBits();
916 APInt TruncMask = NewMask.zext(OperandBitWidth);
917 if (SimplifyDemandedBits(Op.getOperand(0), TruncMask,
918 KnownZero, KnownOne, TLO, Depth+1))
920 KnownZero = KnownZero.trunc(BitWidth);
921 KnownOne = KnownOne.trunc(BitWidth);
923 // If the input is only used by this truncate, see if we can shrink it based
924 // on the known demanded bits.
925 if (Op.getOperand(0).getNode()->hasOneUse()) {
926 SDValue In = Op.getOperand(0);
927 switch (In.getOpcode()) {
930 // Shrink SRL by a constant if none of the high bits shifted in are
932 if (TLO.LegalTypes() &&
933 !isTypeDesirableForOp(ISD::SRL, Op.getValueType()))
934 // Do not turn (vt1 truncate (vt2 srl)) into (vt1 srl) if vt1 is
937 ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(In.getOperand(1));
940 SDValue Shift = In.getOperand(1);
941 if (TLO.LegalTypes()) {
942 uint64_t ShVal = ShAmt->getZExtValue();
944 TLO.DAG.getConstant(ShVal, getShiftAmountTy(Op.getValueType()));
947 APInt HighBits = APInt::getHighBitsSet(OperandBitWidth,
948 OperandBitWidth - BitWidth);
949 HighBits = HighBits.lshr(ShAmt->getZExtValue()).trunc(BitWidth);
951 if (ShAmt->getZExtValue() < BitWidth && !(HighBits & NewMask)) {
952 // None of the shifted in bits are needed. Add a truncate of the
953 // shift input, then shift it.
954 SDValue NewTrunc = TLO.DAG.getNode(ISD::TRUNCATE, dl,
957 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl,
966 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
969 case ISD::AssertZext: {
970 // AssertZext demands all of the high bits, plus any of the low bits
971 // demanded by its users.
972 EVT VT = cast<VTSDNode>(Op.getOperand(1))->getVT();
973 APInt InMask = APInt::getLowBitsSet(BitWidth,
975 if (SimplifyDemandedBits(Op.getOperand(0), ~InMask | NewMask,
976 KnownZero, KnownOne, TLO, Depth+1))
978 assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
980 KnownZero |= ~InMask & NewMask;
984 // If this is an FP->Int bitcast and if the sign bit is the only
985 // thing demanded, turn this into a FGETSIGN.
986 if (!TLO.LegalOperations() &&
987 !Op.getValueType().isVector() &&
988 !Op.getOperand(0).getValueType().isVector() &&
989 NewMask == APInt::getSignBit(Op.getValueType().getSizeInBits()) &&
990 Op.getOperand(0).getValueType().isFloatingPoint()) {
991 bool OpVTLegal = isOperationLegalOrCustom(ISD::FGETSIGN, Op.getValueType());
992 bool i32Legal = isOperationLegalOrCustom(ISD::FGETSIGN, MVT::i32);
993 if ((OpVTLegal || i32Legal) && Op.getValueType().isSimple()) {
994 EVT Ty = OpVTLegal ? Op.getValueType() : MVT::i32;
995 // Make a FGETSIGN + SHL to move the sign bit into the appropriate
996 // place. We expect the SHL to be eliminated by other optimizations.
997 SDValue Sign = TLO.DAG.getNode(ISD::FGETSIGN, dl, Ty, Op.getOperand(0));
998 unsigned OpVTSizeInBits = Op.getValueType().getSizeInBits();
999 if (!OpVTLegal && OpVTSizeInBits > 32)
1000 Sign = TLO.DAG.getNode(ISD::ZERO_EXTEND, dl, Op.getValueType(), Sign);
1001 unsigned ShVal = Op.getValueType().getSizeInBits()-1;
1002 SDValue ShAmt = TLO.DAG.getConstant(ShVal, Op.getValueType());
1003 return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, dl,
1012 // Add, Sub, and Mul don't demand any bits in positions beyond that
1013 // of the highest bit demanded of them.
1014 APInt LoMask = APInt::getLowBitsSet(BitWidth,
1015 BitWidth - NewMask.countLeadingZeros());
1016 if (SimplifyDemandedBits(Op.getOperand(0), LoMask, KnownZero2,
1017 KnownOne2, TLO, Depth+1))
1019 if (SimplifyDemandedBits(Op.getOperand(1), LoMask, KnownZero2,
1020 KnownOne2, TLO, Depth+1))
1022 // See if the operation should be performed at a smaller bit width.
1023 if (TLO.ShrinkDemandedOp(Op, BitWidth, NewMask, dl))
1028 // Just use ComputeMaskedBits to compute output bits.
1029 TLO.DAG.ComputeMaskedBits(Op, KnownZero, KnownOne, Depth);
1033 // If we know the value of all of the demanded bits, return this as a
1035 if ((NewMask & (KnownZero|KnownOne)) == NewMask)
1036 return TLO.CombineTo(Op, TLO.DAG.getConstant(KnownOne, Op.getValueType()));
1041 /// computeMaskedBitsForTargetNode - Determine which of the bits specified
1042 /// in Mask are known to be either zero or one and return them in the
1043 /// KnownZero/KnownOne bitsets.
1044 void TargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
1047 const SelectionDAG &DAG,
1048 unsigned Depth) const {
1049 assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
1050 Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
1051 Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
1052 Op.getOpcode() == ISD::INTRINSIC_VOID) &&
1053 "Should use MaskedValueIsZero if you don't know whether Op"
1054 " is a target node!");
1055 KnownZero = KnownOne = APInt(KnownOne.getBitWidth(), 0);
1058 /// ComputeNumSignBitsForTargetNode - This method can be implemented by
1059 /// targets that want to expose additional information about sign bits to the
1061 unsigned TargetLowering::ComputeNumSignBitsForTargetNode(SDValue Op,
1062 unsigned Depth) const {
1063 assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
1064 Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
1065 Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
1066 Op.getOpcode() == ISD::INTRINSIC_VOID) &&
1067 "Should use ComputeNumSignBits if you don't know whether Op"
1068 " is a target node!");
1072 /// ValueHasExactlyOneBitSet - Test if the given value is known to have exactly
1073 /// one bit set. This differs from ComputeMaskedBits in that it doesn't need to
1074 /// determine which bit is set.
1076 static bool ValueHasExactlyOneBitSet(SDValue Val, const SelectionDAG &DAG) {
1077 // A left-shift of a constant one will have exactly one bit set, because
1078 // shifting the bit off the end is undefined.
1079 if (Val.getOpcode() == ISD::SHL)
1080 if (ConstantSDNode *C =
1081 dyn_cast<ConstantSDNode>(Val.getNode()->getOperand(0)))
1082 if (C->getAPIntValue() == 1)
1085 // Similarly, a right-shift of a constant sign-bit will have exactly
1087 if (Val.getOpcode() == ISD::SRL)
1088 if (ConstantSDNode *C =
1089 dyn_cast<ConstantSDNode>(Val.getNode()->getOperand(0)))
1090 if (C->getAPIntValue().isSignBit())
1093 // More could be done here, though the above checks are enough
1094 // to handle some common cases.
1096 // Fall back to ComputeMaskedBits to catch other known cases.
1097 EVT OpVT = Val.getValueType();
1098 unsigned BitWidth = OpVT.getScalarType().getSizeInBits();
1099 APInt KnownZero, KnownOne;
1100 DAG.ComputeMaskedBits(Val, KnownZero, KnownOne);
1101 return (KnownZero.countPopulation() == BitWidth - 1) &&
1102 (KnownOne.countPopulation() == 1);
1105 /// SimplifySetCC - Try to simplify a setcc built with the specified operands
1106 /// and cc. If it is unable to simplify it, return a null SDValue.
1108 TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
1109 ISD::CondCode Cond, bool foldBooleans,
1110 DAGCombinerInfo &DCI, SDLoc dl) const {
1111 SelectionDAG &DAG = DCI.DAG;
1113 // These setcc operations always fold.
1117 case ISD::SETFALSE2: return DAG.getConstant(0, VT);
1119 case ISD::SETTRUE2: {
1120 TargetLowering::BooleanContent Cnt = getBooleanContents(VT.isVector());
1121 return DAG.getConstant(
1122 Cnt == TargetLowering::ZeroOrNegativeOneBooleanContent ? -1ULL : 1, VT);
1126 // Ensure that the constant occurs on the RHS, and fold constant
1128 ISD::CondCode SwappedCC = ISD::getSetCCSwappedOperands(Cond);
1129 if (isa<ConstantSDNode>(N0.getNode()) &&
1130 (DCI.isBeforeLegalizeOps() ||
1131 isCondCodeLegal(SwappedCC, N0.getSimpleValueType())))
1132 return DAG.getSetCC(dl, VT, N1, N0, SwappedCC);
1134 if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode())) {
1135 const APInt &C1 = N1C->getAPIntValue();
1137 // If the LHS is '(srl (ctlz x), 5)', the RHS is 0/1, and this is an
1138 // equality comparison, then we're just comparing whether X itself is
1140 if (N0.getOpcode() == ISD::SRL && (C1 == 0 || C1 == 1) &&
1141 N0.getOperand(0).getOpcode() == ISD::CTLZ &&
1142 N0.getOperand(1).getOpcode() == ISD::Constant) {
1144 = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
1145 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1146 ShAmt == Log2_32(N0.getValueType().getSizeInBits())) {
1147 if ((C1 == 0) == (Cond == ISD::SETEQ)) {
1148 // (srl (ctlz x), 5) == 0 -> X != 0
1149 // (srl (ctlz x), 5) != 1 -> X != 0
1152 // (srl (ctlz x), 5) != 0 -> X == 0
1153 // (srl (ctlz x), 5) == 1 -> X == 0
1156 SDValue Zero = DAG.getConstant(0, N0.getValueType());
1157 return DAG.getSetCC(dl, VT, N0.getOperand(0).getOperand(0),
1163 // Look through truncs that don't change the value of a ctpop.
1164 if (N0.hasOneUse() && N0.getOpcode() == ISD::TRUNCATE)
1165 CTPOP = N0.getOperand(0);
1167 if (CTPOP.hasOneUse() && CTPOP.getOpcode() == ISD::CTPOP &&
1168 (N0 == CTPOP || N0.getValueType().getSizeInBits() >
1169 Log2_32_Ceil(CTPOP.getValueType().getSizeInBits()))) {
1170 EVT CTVT = CTPOP.getValueType();
1171 SDValue CTOp = CTPOP.getOperand(0);
1173 // (ctpop x) u< 2 -> (x & x-1) == 0
1174 // (ctpop x) u> 1 -> (x & x-1) != 0
1175 if ((Cond == ISD::SETULT && C1 == 2) || (Cond == ISD::SETUGT && C1 == 1)){
1176 SDValue Sub = DAG.getNode(ISD::SUB, dl, CTVT, CTOp,
1177 DAG.getConstant(1, CTVT));
1178 SDValue And = DAG.getNode(ISD::AND, dl, CTVT, CTOp, Sub);
1179 ISD::CondCode CC = Cond == ISD::SETULT ? ISD::SETEQ : ISD::SETNE;
1180 return DAG.getSetCC(dl, VT, And, DAG.getConstant(0, CTVT), CC);
1183 // TODO: (ctpop x) == 1 -> x && (x & x-1) == 0 iff ctpop is illegal.
1186 // (zext x) == C --> x == (trunc C)
1187 if (DCI.isBeforeLegalize() && N0->hasOneUse() &&
1188 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
1189 unsigned MinBits = N0.getValueSizeInBits();
1191 if (N0->getOpcode() == ISD::ZERO_EXTEND) {
1193 MinBits = N0->getOperand(0).getValueSizeInBits();
1194 PreZExt = N0->getOperand(0);
1195 } else if (N0->getOpcode() == ISD::AND) {
1196 // DAGCombine turns costly ZExts into ANDs
1197 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0->getOperand(1)))
1198 if ((C->getAPIntValue()+1).isPowerOf2()) {
1199 MinBits = C->getAPIntValue().countTrailingOnes();
1200 PreZExt = N0->getOperand(0);
1202 } else if (LoadSDNode *LN0 = dyn_cast<LoadSDNode>(N0)) {
1204 if (LN0->getExtensionType() == ISD::ZEXTLOAD) {
1205 MinBits = LN0->getMemoryVT().getSizeInBits();
1210 // Make sure we're not losing bits from the constant.
1212 MinBits < C1.getBitWidth() && MinBits >= C1.getActiveBits()) {
1213 EVT MinVT = EVT::getIntegerVT(*DAG.getContext(), MinBits);
1214 if (isTypeDesirableForOp(ISD::SETCC, MinVT)) {
1215 // Will get folded away.
1216 SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, MinVT, PreZExt);
1217 SDValue C = DAG.getConstant(C1.trunc(MinBits), MinVT);
1218 return DAG.getSetCC(dl, VT, Trunc, C, Cond);
1223 // If the LHS is '(and load, const)', the RHS is 0,
1224 // the test is for equality or unsigned, and all 1 bits of the const are
1225 // in the same partial word, see if we can shorten the load.
1226 if (DCI.isBeforeLegalize() &&
1227 !ISD::isSignedIntSetCC(Cond) &&
1228 N0.getOpcode() == ISD::AND && C1 == 0 &&
1229 N0.getNode()->hasOneUse() &&
1230 isa<LoadSDNode>(N0.getOperand(0)) &&
1231 N0.getOperand(0).getNode()->hasOneUse() &&
1232 isa<ConstantSDNode>(N0.getOperand(1))) {
1233 LoadSDNode *Lod = cast<LoadSDNode>(N0.getOperand(0));
1235 unsigned bestWidth = 0, bestOffset = 0;
1236 if (!Lod->isVolatile() && Lod->isUnindexed()) {
1237 unsigned origWidth = N0.getValueType().getSizeInBits();
1238 unsigned maskWidth = origWidth;
1239 // We can narrow (e.g.) 16-bit extending loads on 32-bit target to
1240 // 8 bits, but have to be careful...
1241 if (Lod->getExtensionType() != ISD::NON_EXTLOAD)
1242 origWidth = Lod->getMemoryVT().getSizeInBits();
1244 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
1245 for (unsigned width = origWidth / 2; width>=8; width /= 2) {
1246 APInt newMask = APInt::getLowBitsSet(maskWidth, width);
1247 for (unsigned offset=0; offset<origWidth/width; offset++) {
1248 if ((newMask & Mask) == Mask) {
1249 if (!getDataLayout()->isLittleEndian())
1250 bestOffset = (origWidth/width - offset - 1) * (width/8);
1252 bestOffset = (uint64_t)offset * (width/8);
1253 bestMask = Mask.lshr(offset * (width/8) * 8);
1257 newMask = newMask << width;
1262 EVT newVT = EVT::getIntegerVT(*DAG.getContext(), bestWidth);
1263 if (newVT.isRound()) {
1264 EVT PtrType = Lod->getOperand(1).getValueType();
1265 SDValue Ptr = Lod->getBasePtr();
1266 if (bestOffset != 0)
1267 Ptr = DAG.getNode(ISD::ADD, dl, PtrType, Lod->getBasePtr(),
1268 DAG.getConstant(bestOffset, PtrType));
1269 unsigned NewAlign = MinAlign(Lod->getAlignment(), bestOffset);
1270 SDValue NewLoad = DAG.getLoad(newVT, dl, Lod->getChain(), Ptr,
1271 Lod->getPointerInfo().getWithOffset(bestOffset),
1272 false, false, false, NewAlign);
1273 return DAG.getSetCC(dl, VT,
1274 DAG.getNode(ISD::AND, dl, newVT, NewLoad,
1275 DAG.getConstant(bestMask.trunc(bestWidth),
1277 DAG.getConstant(0LL, newVT), Cond);
1282 // If the LHS is a ZERO_EXTEND, perform the comparison on the input.
1283 if (N0.getOpcode() == ISD::ZERO_EXTEND) {
1284 unsigned InSize = N0.getOperand(0).getValueType().getSizeInBits();
1286 // If the comparison constant has bits in the upper part, the
1287 // zero-extended value could never match.
1288 if (C1.intersects(APInt::getHighBitsSet(C1.getBitWidth(),
1289 C1.getBitWidth() - InSize))) {
1293 case ISD::SETEQ: return DAG.getConstant(0, VT);
1296 case ISD::SETNE: return DAG.getConstant(1, VT);
1299 // True if the sign bit of C1 is set.
1300 return DAG.getConstant(C1.isNegative(), VT);
1303 // True if the sign bit of C1 isn't set.
1304 return DAG.getConstant(C1.isNonNegative(), VT);
1310 // Otherwise, we can perform the comparison with the low bits.
1318 EVT newVT = N0.getOperand(0).getValueType();
1319 if (DCI.isBeforeLegalizeOps() ||
1320 (isOperationLegal(ISD::SETCC, newVT) &&
1321 getCondCodeAction(Cond, newVT.getSimpleVT())==Legal))
1322 return DAG.getSetCC(dl, VT, N0.getOperand(0),
1323 DAG.getConstant(C1.trunc(InSize), newVT),
1328 break; // todo, be more careful with signed comparisons
1330 } else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
1331 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
1332 EVT ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
1333 unsigned ExtSrcTyBits = ExtSrcTy.getSizeInBits();
1334 EVT ExtDstTy = N0.getValueType();
1335 unsigned ExtDstTyBits = ExtDstTy.getSizeInBits();
1337 // If the constant doesn't fit into the number of bits for the source of
1338 // the sign extension, it is impossible for both sides to be equal.
1339 if (C1.getMinSignedBits() > ExtSrcTyBits)
1340 return DAG.getConstant(Cond == ISD::SETNE, VT);
1343 EVT Op0Ty = N0.getOperand(0).getValueType();
1344 if (Op0Ty == ExtSrcTy) {
1345 ZextOp = N0.getOperand(0);
1347 APInt Imm = APInt::getLowBitsSet(ExtDstTyBits, ExtSrcTyBits);
1348 ZextOp = DAG.getNode(ISD::AND, dl, Op0Ty, N0.getOperand(0),
1349 DAG.getConstant(Imm, Op0Ty));
1351 if (!DCI.isCalledByLegalizer())
1352 DCI.AddToWorklist(ZextOp.getNode());
1353 // Otherwise, make this a use of a zext.
1354 return DAG.getSetCC(dl, VT, ZextOp,
1355 DAG.getConstant(C1 & APInt::getLowBitsSet(
1360 } else if ((N1C->isNullValue() || N1C->getAPIntValue() == 1) &&
1361 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
1362 // SETCC (SETCC), [0|1], [EQ|NE] -> SETCC
1363 if (N0.getOpcode() == ISD::SETCC &&
1364 isTypeLegal(VT) && VT.bitsLE(N0.getValueType())) {
1365 bool TrueWhenTrue = (Cond == ISD::SETEQ) ^ (N1C->getAPIntValue() != 1);
1367 return DAG.getNode(ISD::TRUNCATE, dl, VT, N0);
1368 // Invert the condition.
1369 ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get();
1370 CC = ISD::getSetCCInverse(CC,
1371 N0.getOperand(0).getValueType().isInteger());
1372 if (DCI.isBeforeLegalizeOps() ||
1373 isCondCodeLegal(CC, N0.getOperand(0).getSimpleValueType()))
1374 return DAG.getSetCC(dl, VT, N0.getOperand(0), N0.getOperand(1), CC);
1377 if ((N0.getOpcode() == ISD::XOR ||
1378 (N0.getOpcode() == ISD::AND &&
1379 N0.getOperand(0).getOpcode() == ISD::XOR &&
1380 N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
1381 isa<ConstantSDNode>(N0.getOperand(1)) &&
1382 cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue() == 1) {
1383 // If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We
1384 // can only do this if the top bits are known zero.
1385 unsigned BitWidth = N0.getValueSizeInBits();
1386 if (DAG.MaskedValueIsZero(N0,
1387 APInt::getHighBitsSet(BitWidth,
1389 // Okay, get the un-inverted input value.
1391 if (N0.getOpcode() == ISD::XOR)
1392 Val = N0.getOperand(0);
1394 assert(N0.getOpcode() == ISD::AND &&
1395 N0.getOperand(0).getOpcode() == ISD::XOR);
1396 // ((X^1)&1)^1 -> X & 1
1397 Val = DAG.getNode(ISD::AND, dl, N0.getValueType(),
1398 N0.getOperand(0).getOperand(0),
1402 return DAG.getSetCC(dl, VT, Val, N1,
1403 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
1405 } else if (N1C->getAPIntValue() == 1 &&
1407 getBooleanContents(false) == ZeroOrOneBooleanContent)) {
1409 if (Op0.getOpcode() == ISD::TRUNCATE)
1410 Op0 = Op0.getOperand(0);
1412 if ((Op0.getOpcode() == ISD::XOR) &&
1413 Op0.getOperand(0).getOpcode() == ISD::SETCC &&
1414 Op0.getOperand(1).getOpcode() == ISD::SETCC) {
1415 // (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc)
1416 Cond = (Cond == ISD::SETEQ) ? ISD::SETNE : ISD::SETEQ;
1417 return DAG.getSetCC(dl, VT, Op0.getOperand(0), Op0.getOperand(1),
1420 if (Op0.getOpcode() == ISD::AND &&
1421 isa<ConstantSDNode>(Op0.getOperand(1)) &&
1422 cast<ConstantSDNode>(Op0.getOperand(1))->getAPIntValue() == 1) {
1423 // If this is (X&1) == / != 1, normalize it to (X&1) != / == 0.
1424 if (Op0.getValueType().bitsGT(VT))
1425 Op0 = DAG.getNode(ISD::AND, dl, VT,
1426 DAG.getNode(ISD::TRUNCATE, dl, VT, Op0.getOperand(0)),
1427 DAG.getConstant(1, VT));
1428 else if (Op0.getValueType().bitsLT(VT))
1429 Op0 = DAG.getNode(ISD::AND, dl, VT,
1430 DAG.getNode(ISD::ANY_EXTEND, dl, VT, Op0.getOperand(0)),
1431 DAG.getConstant(1, VT));
1433 return DAG.getSetCC(dl, VT, Op0,
1434 DAG.getConstant(0, Op0.getValueType()),
1435 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
1437 if (Op0.getOpcode() == ISD::AssertZext &&
1438 cast<VTSDNode>(Op0.getOperand(1))->getVT() == MVT::i1)
1439 return DAG.getSetCC(dl, VT, Op0,
1440 DAG.getConstant(0, Op0.getValueType()),
1441 Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
1445 APInt MinVal, MaxVal;
1446 unsigned OperandBitSize = N1C->getValueType(0).getSizeInBits();
1447 if (ISD::isSignedIntSetCC(Cond)) {
1448 MinVal = APInt::getSignedMinValue(OperandBitSize);
1449 MaxVal = APInt::getSignedMaxValue(OperandBitSize);
1451 MinVal = APInt::getMinValue(OperandBitSize);
1452 MaxVal = APInt::getMaxValue(OperandBitSize);
1455 // Canonicalize GE/LE comparisons to use GT/LT comparisons.
1456 if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
1457 if (C1 == MinVal) return DAG.getConstant(1, VT); // X >= MIN --> true
1458 // X >= C0 --> X > (C0-1)
1459 return DAG.getSetCC(dl, VT, N0,
1460 DAG.getConstant(C1-1, N1.getValueType()),
1461 (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT);
1464 if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
1465 if (C1 == MaxVal) return DAG.getConstant(1, VT); // X <= MAX --> true
1466 // X <= C0 --> X < (C0+1)
1467 return DAG.getSetCC(dl, VT, N0,
1468 DAG.getConstant(C1+1, N1.getValueType()),
1469 (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT);
1472 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
1473 return DAG.getConstant(0, VT); // X < MIN --> false
1474 if ((Cond == ISD::SETGE || Cond == ISD::SETUGE) && C1 == MinVal)
1475 return DAG.getConstant(1, VT); // X >= MIN --> true
1476 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal)
1477 return DAG.getConstant(0, VT); // X > MAX --> false
1478 if ((Cond == ISD::SETLE || Cond == ISD::SETULE) && C1 == MaxVal)
1479 return DAG.getConstant(1, VT); // X <= MAX --> true
1481 // Canonicalize setgt X, Min --> setne X, Min
1482 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
1483 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETNE);
1484 // Canonicalize setlt X, Max --> setne X, Max
1485 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal)
1486 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETNE);
1488 // If we have setult X, 1, turn it into seteq X, 0
1489 if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
1490 return DAG.getSetCC(dl, VT, N0,
1491 DAG.getConstant(MinVal, N0.getValueType()),
1493 // If we have setugt X, Max-1, turn it into seteq X, Max
1494 if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
1495 return DAG.getSetCC(dl, VT, N0,
1496 DAG.getConstant(MaxVal, N0.getValueType()),
1499 // If we have "setcc X, C0", check to see if we can shrink the immediate
1502 // SETUGT X, SINTMAX -> SETLT X, 0
1503 if (Cond == ISD::SETUGT &&
1504 C1 == APInt::getSignedMaxValue(OperandBitSize))
1505 return DAG.getSetCC(dl, VT, N0,
1506 DAG.getConstant(0, N1.getValueType()),
1509 // SETULT X, SINTMIN -> SETGT X, -1
1510 if (Cond == ISD::SETULT &&
1511 C1 == APInt::getSignedMinValue(OperandBitSize)) {
1512 SDValue ConstMinusOne =
1513 DAG.getConstant(APInt::getAllOnesValue(OperandBitSize),
1515 return DAG.getSetCC(dl, VT, N0, ConstMinusOne, ISD::SETGT);
1518 // Fold bit comparisons when we can.
1519 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1520 (VT == N0.getValueType() ||
1521 (isTypeLegal(VT) && VT.bitsLE(N0.getValueType()))) &&
1522 N0.getOpcode() == ISD::AND)
1523 if (ConstantSDNode *AndRHS =
1524 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1525 EVT ShiftTy = DCI.isBeforeLegalizeOps() ?
1526 getPointerTy() : getShiftAmountTy(N0.getValueType());
1527 if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
1528 // Perform the xform if the AND RHS is a single bit.
1529 if (AndRHS->getAPIntValue().isPowerOf2()) {
1530 return DAG.getNode(ISD::TRUNCATE, dl, VT,
1531 DAG.getNode(ISD::SRL, dl, N0.getValueType(), N0,
1532 DAG.getConstant(AndRHS->getAPIntValue().logBase2(), ShiftTy)));
1534 } else if (Cond == ISD::SETEQ && C1 == AndRHS->getAPIntValue()) {
1535 // (X & 8) == 8 --> (X & 8) >> 3
1536 // Perform the xform if C1 is a single bit.
1537 if (C1.isPowerOf2()) {
1538 return DAG.getNode(ISD::TRUNCATE, dl, VT,
1539 DAG.getNode(ISD::SRL, dl, N0.getValueType(), N0,
1540 DAG.getConstant(C1.logBase2(), ShiftTy)));
1545 if (C1.getMinSignedBits() <= 64 &&
1546 !isLegalICmpImmediate(C1.getSExtValue())) {
1547 // (X & -256) == 256 -> (X >> 8) == 1
1548 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1549 N0.getOpcode() == ISD::AND && N0.hasOneUse()) {
1550 if (ConstantSDNode *AndRHS =
1551 dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1552 const APInt &AndRHSC = AndRHS->getAPIntValue();
1553 if ((-AndRHSC).isPowerOf2() && (AndRHSC & C1) == C1) {
1554 unsigned ShiftBits = AndRHSC.countTrailingZeros();
1555 EVT ShiftTy = DCI.isBeforeLegalizeOps() ?
1556 getPointerTy() : getShiftAmountTy(N0.getValueType());
1557 EVT CmpTy = N0.getValueType();
1558 SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0.getOperand(0),
1559 DAG.getConstant(ShiftBits, ShiftTy));
1560 SDValue CmpRHS = DAG.getConstant(C1.lshr(ShiftBits), CmpTy);
1561 return DAG.getSetCC(dl, VT, Shift, CmpRHS, Cond);
1564 } else if (Cond == ISD::SETULT || Cond == ISD::SETUGE ||
1565 Cond == ISD::SETULE || Cond == ISD::SETUGT) {
1566 bool AdjOne = (Cond == ISD::SETULE || Cond == ISD::SETUGT);
1567 // X < 0x100000000 -> (X >> 32) < 1
1568 // X >= 0x100000000 -> (X >> 32) >= 1
1569 // X <= 0x0ffffffff -> (X >> 32) < 1
1570 // X > 0x0ffffffff -> (X >> 32) >= 1
1573 ISD::CondCode NewCond = Cond;
1575 ShiftBits = C1.countTrailingOnes();
1577 NewCond = (Cond == ISD::SETULE) ? ISD::SETULT : ISD::SETUGE;
1579 ShiftBits = C1.countTrailingZeros();
1581 NewC = NewC.lshr(ShiftBits);
1582 if (ShiftBits && isLegalICmpImmediate(NewC.getSExtValue())) {
1583 EVT ShiftTy = DCI.isBeforeLegalizeOps() ?
1584 getPointerTy() : getShiftAmountTy(N0.getValueType());
1585 EVT CmpTy = N0.getValueType();
1586 SDValue Shift = DAG.getNode(ISD::SRL, dl, CmpTy, N0,
1587 DAG.getConstant(ShiftBits, ShiftTy));
1588 SDValue CmpRHS = DAG.getConstant(NewC, CmpTy);
1589 return DAG.getSetCC(dl, VT, Shift, CmpRHS, NewCond);
1595 if (isa<ConstantFPSDNode>(N0.getNode())) {
1596 // Constant fold or commute setcc.
1597 SDValue O = DAG.FoldSetCC(VT, N0, N1, Cond, dl);
1598 if (O.getNode()) return O;
1599 } else if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1.getNode())) {
1600 // If the RHS of an FP comparison is a constant, simplify it away in
1602 if (CFP->getValueAPF().isNaN()) {
1603 // If an operand is known to be a nan, we can fold it.
1604 switch (ISD::getUnorderedFlavor(Cond)) {
1605 default: llvm_unreachable("Unknown flavor!");
1606 case 0: // Known false.
1607 return DAG.getConstant(0, VT);
1608 case 1: // Known true.
1609 return DAG.getConstant(1, VT);
1610 case 2: // Undefined.
1611 return DAG.getUNDEF(VT);
1615 // Otherwise, we know the RHS is not a NaN. Simplify the node to drop the
1616 // constant if knowing that the operand is non-nan is enough. We prefer to
1617 // have SETO(x,x) instead of SETO(x, 0.0) because this avoids having to
1619 if (Cond == ISD::SETO || Cond == ISD::SETUO)
1620 return DAG.getSetCC(dl, VT, N0, N0, Cond);
1622 // If the condition is not legal, see if we can find an equivalent one
1624 if (!isCondCodeLegal(Cond, N0.getSimpleValueType())) {
1625 // If the comparison was an awkward floating-point == or != and one of
1626 // the comparison operands is infinity or negative infinity, convert the
1627 // condition to a less-awkward <= or >=.
1628 if (CFP->getValueAPF().isInfinity()) {
1629 if (CFP->getValueAPF().isNegative()) {
1630 if (Cond == ISD::SETOEQ &&
1631 isCondCodeLegal(ISD::SETOLE, N0.getSimpleValueType()))
1632 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOLE);
1633 if (Cond == ISD::SETUEQ &&
1634 isCondCodeLegal(ISD::SETOLE, N0.getSimpleValueType()))
1635 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETULE);
1636 if (Cond == ISD::SETUNE &&
1637 isCondCodeLegal(ISD::SETUGT, N0.getSimpleValueType()))
1638 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETUGT);
1639 if (Cond == ISD::SETONE &&
1640 isCondCodeLegal(ISD::SETUGT, N0.getSimpleValueType()))
1641 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOGT);
1643 if (Cond == ISD::SETOEQ &&
1644 isCondCodeLegal(ISD::SETOGE, N0.getSimpleValueType()))
1645 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOGE);
1646 if (Cond == ISD::SETUEQ &&
1647 isCondCodeLegal(ISD::SETOGE, N0.getSimpleValueType()))
1648 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETUGE);
1649 if (Cond == ISD::SETUNE &&
1650 isCondCodeLegal(ISD::SETULT, N0.getSimpleValueType()))
1651 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETULT);
1652 if (Cond == ISD::SETONE &&
1653 isCondCodeLegal(ISD::SETULT, N0.getSimpleValueType()))
1654 return DAG.getSetCC(dl, VT, N0, N1, ISD::SETOLT);
1661 // The sext(setcc()) => setcc() optimization relies on the appropriate
1662 // constant being emitted.
1664 switch (getBooleanContents(N0.getValueType().isVector())) {
1665 case UndefinedBooleanContent:
1666 case ZeroOrOneBooleanContent:
1667 EqVal = ISD::isTrueWhenEqual(Cond);
1669 case ZeroOrNegativeOneBooleanContent:
1670 EqVal = ISD::isTrueWhenEqual(Cond) ? -1 : 0;
1674 // We can always fold X == X for integer setcc's.
1675 if (N0.getValueType().isInteger()) {
1676 return DAG.getConstant(EqVal, VT);
1678 unsigned UOF = ISD::getUnorderedFlavor(Cond);
1679 if (UOF == 2) // FP operators that are undefined on NaNs.
1680 return DAG.getConstant(EqVal, VT);
1681 if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
1682 return DAG.getConstant(EqVal, VT);
1683 // Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
1684 // if it is not already.
1685 ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
1686 if (NewCond != Cond && (DCI.isBeforeLegalizeOps() ||
1687 getCondCodeAction(NewCond, N0.getSimpleValueType()) == Legal))
1688 return DAG.getSetCC(dl, VT, N0, N1, NewCond);
1691 if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
1692 N0.getValueType().isInteger()) {
1693 if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
1694 N0.getOpcode() == ISD::XOR) {
1695 // Simplify (X+Y) == (X+Z) --> Y == Z
1696 if (N0.getOpcode() == N1.getOpcode()) {
1697 if (N0.getOperand(0) == N1.getOperand(0))
1698 return DAG.getSetCC(dl, VT, N0.getOperand(1), N1.getOperand(1), Cond);
1699 if (N0.getOperand(1) == N1.getOperand(1))
1700 return DAG.getSetCC(dl, VT, N0.getOperand(0), N1.getOperand(0), Cond);
1701 if (DAG.isCommutativeBinOp(N0.getOpcode())) {
1702 // If X op Y == Y op X, try other combinations.
1703 if (N0.getOperand(0) == N1.getOperand(1))
1704 return DAG.getSetCC(dl, VT, N0.getOperand(1), N1.getOperand(0),
1706 if (N0.getOperand(1) == N1.getOperand(0))
1707 return DAG.getSetCC(dl, VT, N0.getOperand(0), N1.getOperand(1),
1712 // If RHS is a legal immediate value for a compare instruction, we need
1713 // to be careful about increasing register pressure needlessly.
1714 bool LegalRHSImm = false;
1716 if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) {
1717 if (ConstantSDNode *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
1718 // Turn (X+C1) == C2 --> X == C2-C1
1719 if (N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse()) {
1720 return DAG.getSetCC(dl, VT, N0.getOperand(0),
1721 DAG.getConstant(RHSC->getAPIntValue()-
1722 LHSR->getAPIntValue(),
1723 N0.getValueType()), Cond);
1726 // Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0.
1727 if (N0.getOpcode() == ISD::XOR)
1728 // If we know that all of the inverted bits are zero, don't bother
1729 // performing the inversion.
1730 if (DAG.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getAPIntValue()))
1732 DAG.getSetCC(dl, VT, N0.getOperand(0),
1733 DAG.getConstant(LHSR->getAPIntValue() ^
1734 RHSC->getAPIntValue(),
1739 // Turn (C1-X) == C2 --> X == C1-C2
1740 if (ConstantSDNode *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) {
1741 if (N0.getOpcode() == ISD::SUB && N0.getNode()->hasOneUse()) {
1743 DAG.getSetCC(dl, VT, N0.getOperand(1),
1744 DAG.getConstant(SUBC->getAPIntValue() -
1745 RHSC->getAPIntValue(),
1751 // Could RHSC fold directly into a compare?
1752 if (RHSC->getValueType(0).getSizeInBits() <= 64)
1753 LegalRHSImm = isLegalICmpImmediate(RHSC->getSExtValue());
1756 // Simplify (X+Z) == X --> Z == 0
1757 // Don't do this if X is an immediate that can fold into a cmp
1758 // instruction and X+Z has other uses. It could be an induction variable
1759 // chain, and the transform would increase register pressure.
1760 if (!LegalRHSImm || N0.getNode()->hasOneUse()) {
1761 if (N0.getOperand(0) == N1)
1762 return DAG.getSetCC(dl, VT, N0.getOperand(1),
1763 DAG.getConstant(0, N0.getValueType()), Cond);
1764 if (N0.getOperand(1) == N1) {
1765 if (DAG.isCommutativeBinOp(N0.getOpcode()))
1766 return DAG.getSetCC(dl, VT, N0.getOperand(0),
1767 DAG.getConstant(0, N0.getValueType()), Cond);
1768 if (N0.getNode()->hasOneUse()) {
1769 assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
1770 // (Z-X) == X --> Z == X<<1
1771 SDValue SH = DAG.getNode(ISD::SHL, dl, N1.getValueType(), N1,
1772 DAG.getConstant(1, getShiftAmountTy(N1.getValueType())));
1773 if (!DCI.isCalledByLegalizer())
1774 DCI.AddToWorklist(SH.getNode());
1775 return DAG.getSetCC(dl, VT, N0.getOperand(0), SH, Cond);
1781 if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
1782 N1.getOpcode() == ISD::XOR) {
1783 // Simplify X == (X+Z) --> Z == 0
1784 if (N1.getOperand(0) == N0)
1785 return DAG.getSetCC(dl, VT, N1.getOperand(1),
1786 DAG.getConstant(0, N1.getValueType()), Cond);
1787 if (N1.getOperand(1) == N0) {
1788 if (DAG.isCommutativeBinOp(N1.getOpcode()))
1789 return DAG.getSetCC(dl, VT, N1.getOperand(0),
1790 DAG.getConstant(0, N1.getValueType()), Cond);
1791 if (N1.getNode()->hasOneUse()) {
1792 assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
1793 // X == (Z-X) --> X<<1 == Z
1794 SDValue SH = DAG.getNode(ISD::SHL, dl, N1.getValueType(), N0,
1795 DAG.getConstant(1, getShiftAmountTy(N0.getValueType())));
1796 if (!DCI.isCalledByLegalizer())
1797 DCI.AddToWorklist(SH.getNode());
1798 return DAG.getSetCC(dl, VT, SH, N1.getOperand(0), Cond);
1803 // Simplify x&y == y to x&y != 0 if y has exactly one bit set.
1804 // Note that where y is variable and is known to have at most
1805 // one bit set (for example, if it is z&1) we cannot do this;
1806 // the expressions are not equivalent when y==0.
1807 if (N0.getOpcode() == ISD::AND)
1808 if (N0.getOperand(0) == N1 || N0.getOperand(1) == N1) {
1809 if (ValueHasExactlyOneBitSet(N1, DAG)) {
1810 Cond = ISD::getSetCCInverse(Cond, /*isInteger=*/true);
1811 if (DCI.isBeforeLegalizeOps() ||
1812 isCondCodeLegal(Cond, N0.getSimpleValueType())) {
1813 SDValue Zero = DAG.getConstant(0, N1.getValueType());
1814 return DAG.getSetCC(dl, VT, N0, Zero, Cond);
1818 if (N1.getOpcode() == ISD::AND)
1819 if (N1.getOperand(0) == N0 || N1.getOperand(1) == N0) {
1820 if (ValueHasExactlyOneBitSet(N0, DAG)) {
1821 Cond = ISD::getSetCCInverse(Cond, /*isInteger=*/true);
1822 if (DCI.isBeforeLegalizeOps() ||
1823 isCondCodeLegal(Cond, N1.getSimpleValueType())) {
1824 SDValue Zero = DAG.getConstant(0, N0.getValueType());
1825 return DAG.getSetCC(dl, VT, N1, Zero, Cond);
1831 // Fold away ALL boolean setcc's.
1833 if (N0.getValueType() == MVT::i1 && foldBooleans) {
1835 default: llvm_unreachable("Unknown integer setcc!");
1836 case ISD::SETEQ: // X == Y -> ~(X^Y)
1837 Temp = DAG.getNode(ISD::XOR, dl, MVT::i1, N0, N1);
1838 N0 = DAG.getNOT(dl, Temp, MVT::i1);
1839 if (!DCI.isCalledByLegalizer())
1840 DCI.AddToWorklist(Temp.getNode());
1842 case ISD::SETNE: // X != Y --> (X^Y)
1843 N0 = DAG.getNode(ISD::XOR, dl, MVT::i1, N0, N1);
1845 case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> ~X & Y
1846 case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> ~X & Y
1847 Temp = DAG.getNOT(dl, N0, MVT::i1);
1848 N0 = DAG.getNode(ISD::AND, dl, MVT::i1, N1, Temp);
1849 if (!DCI.isCalledByLegalizer())
1850 DCI.AddToWorklist(Temp.getNode());
1852 case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> ~Y & X
1853 case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> ~Y & X
1854 Temp = DAG.getNOT(dl, N1, MVT::i1);
1855 N0 = DAG.getNode(ISD::AND, dl, MVT::i1, N0, Temp);
1856 if (!DCI.isCalledByLegalizer())
1857 DCI.AddToWorklist(Temp.getNode());
1859 case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> ~X | Y
1860 case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> ~X | Y
1861 Temp = DAG.getNOT(dl, N0, MVT::i1);
1862 N0 = DAG.getNode(ISD::OR, dl, MVT::i1, N1, Temp);
1863 if (!DCI.isCalledByLegalizer())
1864 DCI.AddToWorklist(Temp.getNode());
1866 case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> ~Y | X
1867 case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> ~Y | X
1868 Temp = DAG.getNOT(dl, N1, MVT::i1);
1869 N0 = DAG.getNode(ISD::OR, dl, MVT::i1, N0, Temp);
1872 if (VT != MVT::i1) {
1873 if (!DCI.isCalledByLegalizer())
1874 DCI.AddToWorklist(N0.getNode());
1875 // FIXME: If running after legalize, we probably can't do this.
1876 N0 = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, N0);
1881 // Could not fold it.
1885 /// isGAPlusOffset - Returns true (and the GlobalValue and the offset) if the
1886 /// node is a GlobalAddress + offset.
1887 bool TargetLowering::isGAPlusOffset(SDNode *N, const GlobalValue *&GA,
1888 int64_t &Offset) const {
1889 if (isa<GlobalAddressSDNode>(N)) {
1890 GlobalAddressSDNode *GASD = cast<GlobalAddressSDNode>(N);
1891 GA = GASD->getGlobal();
1892 Offset += GASD->getOffset();
1896 if (N->getOpcode() == ISD::ADD) {
1897 SDValue N1 = N->getOperand(0);
1898 SDValue N2 = N->getOperand(1);
1899 if (isGAPlusOffset(N1.getNode(), GA, Offset)) {
1900 ConstantSDNode *V = dyn_cast<ConstantSDNode>(N2);
1902 Offset += V->getSExtValue();
1905 } else if (isGAPlusOffset(N2.getNode(), GA, Offset)) {
1906 ConstantSDNode *V = dyn_cast<ConstantSDNode>(N1);
1908 Offset += V->getSExtValue();
1918 SDValue TargetLowering::
1919 PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const {
1920 // Default implementation: no optimization.
1924 //===----------------------------------------------------------------------===//
1925 // Inline Assembler Implementation Methods
1926 //===----------------------------------------------------------------------===//
1929 TargetLowering::ConstraintType
1930 TargetLowering::getConstraintType(const std::string &Constraint) const {
1931 unsigned S = Constraint.size();
1934 switch (Constraint[0]) {
1936 case 'r': return C_RegisterClass;
1938 case 'o': // offsetable
1939 case 'V': // not offsetable
1941 case 'i': // Simple Integer or Relocatable Constant
1942 case 'n': // Simple Integer
1943 case 'E': // Floating Point Constant
1944 case 'F': // Floating Point Constant
1945 case 's': // Relocatable Constant
1946 case 'p': // Address.
1947 case 'X': // Allow ANY value.
1948 case 'I': // Target registers.
1962 if (S > 1 && Constraint[0] == '{' && Constraint[S-1] == '}') {
1963 if (S == 8 && !Constraint.compare(1, 6, "memory", 6)) // "{memory}"
1970 /// LowerXConstraint - try to replace an X constraint, which matches anything,
1971 /// with another that has more specific requirements based on the type of the
1972 /// corresponding operand.
1973 const char *TargetLowering::LowerXConstraint(EVT ConstraintVT) const{
1974 if (ConstraintVT.isInteger())
1976 if (ConstraintVT.isFloatingPoint())
1977 return "f"; // works for many targets
1981 /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
1982 /// vector. If it is invalid, don't add anything to Ops.
1983 void TargetLowering::LowerAsmOperandForConstraint(SDValue Op,
1984 std::string &Constraint,
1985 std::vector<SDValue> &Ops,
1986 SelectionDAG &DAG) const {
1988 if (Constraint.length() > 1) return;
1990 char ConstraintLetter = Constraint[0];
1991 switch (ConstraintLetter) {
1993 case 'X': // Allows any operand; labels (basic block) use this.
1994 if (Op.getOpcode() == ISD::BasicBlock) {
1999 case 'i': // Simple Integer or Relocatable Constant
2000 case 'n': // Simple Integer
2001 case 's': { // Relocatable Constant
2002 // These operands are interested in values of the form (GV+C), where C may
2003 // be folded in as an offset of GV, or it may be explicitly added. Also, it
2004 // is possible and fine if either GV or C are missing.
2005 ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op);
2006 GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Op);
2008 // If we have "(add GV, C)", pull out GV/C
2009 if (Op.getOpcode() == ISD::ADD) {
2010 C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
2011 GA = dyn_cast<GlobalAddressSDNode>(Op.getOperand(0));
2012 if (C == 0 || GA == 0) {
2013 C = dyn_cast<ConstantSDNode>(Op.getOperand(0));
2014 GA = dyn_cast<GlobalAddressSDNode>(Op.getOperand(1));
2016 if (C == 0 || GA == 0)
2020 // If we find a valid operand, map to the TargetXXX version so that the
2021 // value itself doesn't get selected.
2022 if (GA) { // Either &GV or &GV+C
2023 if (ConstraintLetter != 'n') {
2024 int64_t Offs = GA->getOffset();
2025 if (C) Offs += C->getZExtValue();
2026 Ops.push_back(DAG.getTargetGlobalAddress(GA->getGlobal(),
2027 C ? SDLoc(C) : SDLoc(),
2028 Op.getValueType(), Offs));
2032 if (C) { // just C, no GV.
2033 // Simple constants are not allowed for 's'.
2034 if (ConstraintLetter != 's') {
2035 // gcc prints these as sign extended. Sign extend value to 64 bits
2036 // now; without this it would get ZExt'd later in
2037 // ScheduleDAGSDNodes::EmitNode, which is very generic.
2038 Ops.push_back(DAG.getTargetConstant(C->getAPIntValue().getSExtValue(),
2048 std::pair<unsigned, const TargetRegisterClass*> TargetLowering::
2049 getRegForInlineAsmConstraint(const std::string &Constraint,
2051 if (Constraint.empty() || Constraint[0] != '{')
2052 return std::make_pair(0u, static_cast<TargetRegisterClass*>(0));
2053 assert(*(Constraint.end()-1) == '}' && "Not a brace enclosed constraint?");
2055 // Remove the braces from around the name.
2056 StringRef RegName(Constraint.data()+1, Constraint.size()-2);
2058 std::pair<unsigned, const TargetRegisterClass*> R =
2059 std::make_pair(0u, static_cast<const TargetRegisterClass*>(0));
2061 // Figure out which register class contains this reg.
2062 const TargetRegisterInfo *RI = getTargetMachine().getRegisterInfo();
2063 for (TargetRegisterInfo::regclass_iterator RCI = RI->regclass_begin(),
2064 E = RI->regclass_end(); RCI != E; ++RCI) {
2065 const TargetRegisterClass *RC = *RCI;
2067 // If none of the value types for this register class are valid, we
2068 // can't use it. For example, 64-bit reg classes on 32-bit targets.
2072 for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
2074 if (RegName.equals_lower(RI->getName(*I))) {
2075 std::pair<unsigned, const TargetRegisterClass*> S =
2076 std::make_pair(*I, RC);
2078 // If this register class has the requested value type, return it,
2079 // otherwise keep searching and return the first class found
2080 // if no other is found which explicitly has the requested type.
2081 if (RC->hasType(VT))
2092 //===----------------------------------------------------------------------===//
2093 // Constraint Selection.
2095 /// isMatchingInputConstraint - Return true of this is an input operand that is
2096 /// a matching constraint like "4".
2097 bool TargetLowering::AsmOperandInfo::isMatchingInputConstraint() const {
2098 assert(!ConstraintCode.empty() && "No known constraint!");
2099 return isdigit(static_cast<unsigned char>(ConstraintCode[0]));
2102 /// getMatchedOperand - If this is an input matching constraint, this method
2103 /// returns the output operand it matches.
2104 unsigned TargetLowering::AsmOperandInfo::getMatchedOperand() const {
2105 assert(!ConstraintCode.empty() && "No known constraint!");
2106 return atoi(ConstraintCode.c_str());
2110 /// ParseConstraints - Split up the constraint string from the inline
2111 /// assembly value into the specific constraints and their prefixes,
2112 /// and also tie in the associated operand values.
2113 /// If this returns an empty vector, and if the constraint string itself
2114 /// isn't empty, there was an error parsing.
2115 TargetLowering::AsmOperandInfoVector TargetLowering::ParseConstraints(
2116 ImmutableCallSite CS) const {
2117 /// ConstraintOperands - Information about all of the constraints.
2118 AsmOperandInfoVector ConstraintOperands;
2119 const InlineAsm *IA = cast<InlineAsm>(CS.getCalledValue());
2120 unsigned maCount = 0; // Largest number of multiple alternative constraints.
2122 // Do a prepass over the constraints, canonicalizing them, and building up the
2123 // ConstraintOperands list.
2124 InlineAsm::ConstraintInfoVector
2125 ConstraintInfos = IA->ParseConstraints();
2127 unsigned ArgNo = 0; // ArgNo - The argument of the CallInst.
2128 unsigned ResNo = 0; // ResNo - The result number of the next output.
2130 for (unsigned i = 0, e = ConstraintInfos.size(); i != e; ++i) {
2131 ConstraintOperands.push_back(AsmOperandInfo(ConstraintInfos[i]));
2132 AsmOperandInfo &OpInfo = ConstraintOperands.back();
2134 // Update multiple alternative constraint count.
2135 if (OpInfo.multipleAlternatives.size() > maCount)
2136 maCount = OpInfo.multipleAlternatives.size();
2138 OpInfo.ConstraintVT = MVT::Other;
2140 // Compute the value type for each operand.
2141 switch (OpInfo.Type) {
2142 case InlineAsm::isOutput:
2143 // Indirect outputs just consume an argument.
2144 if (OpInfo.isIndirect) {
2145 OpInfo.CallOperandVal = const_cast<Value *>(CS.getArgument(ArgNo++));
2149 // The return value of the call is this value. As such, there is no
2150 // corresponding argument.
2151 assert(!CS.getType()->isVoidTy() &&
2153 if (StructType *STy = dyn_cast<StructType>(CS.getType())) {
2154 OpInfo.ConstraintVT = getSimpleValueType(STy->getElementType(ResNo));
2156 assert(ResNo == 0 && "Asm only has one result!");
2157 OpInfo.ConstraintVT = getSimpleValueType(CS.getType());
2161 case InlineAsm::isInput:
2162 OpInfo.CallOperandVal = const_cast<Value *>(CS.getArgument(ArgNo++));
2164 case InlineAsm::isClobber:
2169 if (OpInfo.CallOperandVal) {
2170 llvm::Type *OpTy = OpInfo.CallOperandVal->getType();
2171 if (OpInfo.isIndirect) {
2172 llvm::PointerType *PtrTy = dyn_cast<PointerType>(OpTy);
2174 report_fatal_error("Indirect operand for inline asm not a pointer!");
2175 OpTy = PtrTy->getElementType();
2178 // Look for vector wrapped in a struct. e.g. { <16 x i8> }.
2179 if (StructType *STy = dyn_cast<StructType>(OpTy))
2180 if (STy->getNumElements() == 1)
2181 OpTy = STy->getElementType(0);
2183 // If OpTy is not a single value, it may be a struct/union that we
2184 // can tile with integers.
2185 if (!OpTy->isSingleValueType() && OpTy->isSized()) {
2186 unsigned BitSize = getDataLayout()->getTypeSizeInBits(OpTy);
2195 OpInfo.ConstraintVT =
2196 MVT::getVT(IntegerType::get(OpTy->getContext(), BitSize), true);
2199 } else if (PointerType *PT = dyn_cast<PointerType>(OpTy)) {
2201 = getDataLayout()->getPointerSizeInBits(PT->getAddressSpace());
2202 OpInfo.ConstraintVT = MVT::getIntegerVT(PtrSize);
2204 OpInfo.ConstraintVT = MVT::getVT(OpTy, true);
2209 // If we have multiple alternative constraints, select the best alternative.
2210 if (ConstraintInfos.size()) {
2212 unsigned bestMAIndex = 0;
2213 int bestWeight = -1;
2214 // weight: -1 = invalid match, and 0 = so-so match to 5 = good match.
2217 // Compute the sums of the weights for each alternative, keeping track
2218 // of the best (highest weight) one so far.
2219 for (maIndex = 0; maIndex < maCount; ++maIndex) {
2221 for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
2222 cIndex != eIndex; ++cIndex) {
2223 AsmOperandInfo& OpInfo = ConstraintOperands[cIndex];
2224 if (OpInfo.Type == InlineAsm::isClobber)
2227 // If this is an output operand with a matching input operand,
2228 // look up the matching input. If their types mismatch, e.g. one
2229 // is an integer, the other is floating point, or their sizes are
2230 // different, flag it as an maCantMatch.
2231 if (OpInfo.hasMatchingInput()) {
2232 AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
2233 if (OpInfo.ConstraintVT != Input.ConstraintVT) {
2234 if ((OpInfo.ConstraintVT.isInteger() !=
2235 Input.ConstraintVT.isInteger()) ||
2236 (OpInfo.ConstraintVT.getSizeInBits() !=
2237 Input.ConstraintVT.getSizeInBits())) {
2238 weightSum = -1; // Can't match.
2243 weight = getMultipleConstraintMatchWeight(OpInfo, maIndex);
2248 weightSum += weight;
2251 if (weightSum > bestWeight) {
2252 bestWeight = weightSum;
2253 bestMAIndex = maIndex;
2257 // Now select chosen alternative in each constraint.
2258 for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
2259 cIndex != eIndex; ++cIndex) {
2260 AsmOperandInfo& cInfo = ConstraintOperands[cIndex];
2261 if (cInfo.Type == InlineAsm::isClobber)
2263 cInfo.selectAlternative(bestMAIndex);
2268 // Check and hook up tied operands, choose constraint code to use.
2269 for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
2270 cIndex != eIndex; ++cIndex) {
2271 AsmOperandInfo& OpInfo = ConstraintOperands[cIndex];
2273 // If this is an output operand with a matching input operand, look up the
2274 // matching input. If their types mismatch, e.g. one is an integer, the
2275 // other is floating point, or their sizes are different, flag it as an
2277 if (OpInfo.hasMatchingInput()) {
2278 AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
2280 if (OpInfo.ConstraintVT != Input.ConstraintVT) {
2281 std::pair<unsigned, const TargetRegisterClass*> MatchRC =
2282 getRegForInlineAsmConstraint(OpInfo.ConstraintCode,
2283 OpInfo.ConstraintVT);
2284 std::pair<unsigned, const TargetRegisterClass*> InputRC =
2285 getRegForInlineAsmConstraint(Input.ConstraintCode,
2286 Input.ConstraintVT);
2287 if ((OpInfo.ConstraintVT.isInteger() !=
2288 Input.ConstraintVT.isInteger()) ||
2289 (MatchRC.second != InputRC.second)) {
2290 report_fatal_error("Unsupported asm: input constraint"
2291 " with a matching output constraint of"
2292 " incompatible type!");
2299 return ConstraintOperands;
2303 /// getConstraintGenerality - Return an integer indicating how general CT
2305 static unsigned getConstraintGenerality(TargetLowering::ConstraintType CT) {
2307 case TargetLowering::C_Other:
2308 case TargetLowering::C_Unknown:
2310 case TargetLowering::C_Register:
2312 case TargetLowering::C_RegisterClass:
2314 case TargetLowering::C_Memory:
2317 llvm_unreachable("Invalid constraint type");
2320 /// Examine constraint type and operand type and determine a weight value.
2321 /// This object must already have been set up with the operand type
2322 /// and the current alternative constraint selected.
2323 TargetLowering::ConstraintWeight
2324 TargetLowering::getMultipleConstraintMatchWeight(
2325 AsmOperandInfo &info, int maIndex) const {
2326 InlineAsm::ConstraintCodeVector *rCodes;
2327 if (maIndex >= (int)info.multipleAlternatives.size())
2328 rCodes = &info.Codes;
2330 rCodes = &info.multipleAlternatives[maIndex].Codes;
2331 ConstraintWeight BestWeight = CW_Invalid;
2333 // Loop over the options, keeping track of the most general one.
2334 for (unsigned i = 0, e = rCodes->size(); i != e; ++i) {
2335 ConstraintWeight weight =
2336 getSingleConstraintMatchWeight(info, (*rCodes)[i].c_str());
2337 if (weight > BestWeight)
2338 BestWeight = weight;
2344 /// Examine constraint type and operand type and determine a weight value.
2345 /// This object must already have been set up with the operand type
2346 /// and the current alternative constraint selected.
2347 TargetLowering::ConstraintWeight
2348 TargetLowering::getSingleConstraintMatchWeight(
2349 AsmOperandInfo &info, const char *constraint) const {
2350 ConstraintWeight weight = CW_Invalid;
2351 Value *CallOperandVal = info.CallOperandVal;
2352 // If we don't have a value, we can't do a match,
2353 // but allow it at the lowest weight.
2354 if (CallOperandVal == NULL)
2356 // Look at the constraint type.
2357 switch (*constraint) {
2358 case 'i': // immediate integer.
2359 case 'n': // immediate integer with a known value.
2360 if (isa<ConstantInt>(CallOperandVal))
2361 weight = CW_Constant;
2363 case 's': // non-explicit intregal immediate.
2364 if (isa<GlobalValue>(CallOperandVal))
2365 weight = CW_Constant;
2367 case 'E': // immediate float if host format.
2368 case 'F': // immediate float.
2369 if (isa<ConstantFP>(CallOperandVal))
2370 weight = CW_Constant;
2372 case '<': // memory operand with autodecrement.
2373 case '>': // memory operand with autoincrement.
2374 case 'm': // memory operand.
2375 case 'o': // offsettable memory operand
2376 case 'V': // non-offsettable memory operand
2379 case 'r': // general register.
2380 case 'g': // general register, memory operand or immediate integer.
2381 // note: Clang converts "g" to "imr".
2382 if (CallOperandVal->getType()->isIntegerTy())
2383 weight = CW_Register;
2385 case 'X': // any operand.
2387 weight = CW_Default;
2393 /// ChooseConstraint - If there are multiple different constraints that we
2394 /// could pick for this operand (e.g. "imr") try to pick the 'best' one.
2395 /// This is somewhat tricky: constraints fall into four classes:
2396 /// Other -> immediates and magic values
2397 /// Register -> one specific register
2398 /// RegisterClass -> a group of regs
2399 /// Memory -> memory
2400 /// Ideally, we would pick the most specific constraint possible: if we have
2401 /// something that fits into a register, we would pick it. The problem here
2402 /// is that if we have something that could either be in a register or in
2403 /// memory that use of the register could cause selection of *other*
2404 /// operands to fail: they might only succeed if we pick memory. Because of
2405 /// this the heuristic we use is:
2407 /// 1) If there is an 'other' constraint, and if the operand is valid for
2408 /// that constraint, use it. This makes us take advantage of 'i'
2409 /// constraints when available.
2410 /// 2) Otherwise, pick the most general constraint present. This prefers
2411 /// 'm' over 'r', for example.
2413 static void ChooseConstraint(TargetLowering::AsmOperandInfo &OpInfo,
2414 const TargetLowering &TLI,
2415 SDValue Op, SelectionDAG *DAG) {
2416 assert(OpInfo.Codes.size() > 1 && "Doesn't have multiple constraint options");
2417 unsigned BestIdx = 0;
2418 TargetLowering::ConstraintType BestType = TargetLowering::C_Unknown;
2419 int BestGenerality = -1;
2421 // Loop over the options, keeping track of the most general one.
2422 for (unsigned i = 0, e = OpInfo.Codes.size(); i != e; ++i) {
2423 TargetLowering::ConstraintType CType =
2424 TLI.getConstraintType(OpInfo.Codes[i]);
2426 // If this is an 'other' constraint, see if the operand is valid for it.
2427 // For example, on X86 we might have an 'rI' constraint. If the operand
2428 // is an integer in the range [0..31] we want to use I (saving a load
2429 // of a register), otherwise we must use 'r'.
2430 if (CType == TargetLowering::C_Other && Op.getNode()) {
2431 assert(OpInfo.Codes[i].size() == 1 &&
2432 "Unhandled multi-letter 'other' constraint");
2433 std::vector<SDValue> ResultOps;
2434 TLI.LowerAsmOperandForConstraint(Op, OpInfo.Codes[i],
2436 if (!ResultOps.empty()) {
2443 // Things with matching constraints can only be registers, per gcc
2444 // documentation. This mainly affects "g" constraints.
2445 if (CType == TargetLowering::C_Memory && OpInfo.hasMatchingInput())
2448 // This constraint letter is more general than the previous one, use it.
2449 int Generality = getConstraintGenerality(CType);
2450 if (Generality > BestGenerality) {
2453 BestGenerality = Generality;
2457 OpInfo.ConstraintCode = OpInfo.Codes[BestIdx];
2458 OpInfo.ConstraintType = BestType;
2461 /// ComputeConstraintToUse - Determines the constraint code and constraint
2462 /// type to use for the specific AsmOperandInfo, setting
2463 /// OpInfo.ConstraintCode and OpInfo.ConstraintType.
2464 void TargetLowering::ComputeConstraintToUse(AsmOperandInfo &OpInfo,
2466 SelectionDAG *DAG) const {
2467 assert(!OpInfo.Codes.empty() && "Must have at least one constraint");
2469 // Single-letter constraints ('r') are very common.
2470 if (OpInfo.Codes.size() == 1) {
2471 OpInfo.ConstraintCode = OpInfo.Codes[0];
2472 OpInfo.ConstraintType = getConstraintType(OpInfo.ConstraintCode);
2474 ChooseConstraint(OpInfo, *this, Op, DAG);
2477 // 'X' matches anything.
2478 if (OpInfo.ConstraintCode == "X" && OpInfo.CallOperandVal) {
2479 // Labels and constants are handled elsewhere ('X' is the only thing
2480 // that matches labels). For Functions, the type here is the type of
2481 // the result, which is not what we want to look at; leave them alone.
2482 Value *v = OpInfo.CallOperandVal;
2483 if (isa<BasicBlock>(v) || isa<ConstantInt>(v) || isa<Function>(v)) {
2484 OpInfo.CallOperandVal = v;
2488 // Otherwise, try to resolve it to something we know about by looking at
2489 // the actual operand type.
2490 if (const char *Repl = LowerXConstraint(OpInfo.ConstraintVT)) {
2491 OpInfo.ConstraintCode = Repl;
2492 OpInfo.ConstraintType = getConstraintType(OpInfo.ConstraintCode);
2497 /// \brief Given an exact SDIV by a constant, create a multiplication
2498 /// with the multiplicative inverse of the constant.
2499 SDValue TargetLowering::BuildExactSDIV(SDValue Op1, SDValue Op2, SDLoc dl,
2500 SelectionDAG &DAG) const {
2501 ConstantSDNode *C = cast<ConstantSDNode>(Op2);
2502 APInt d = C->getAPIntValue();
2503 assert(d != 0 && "Division by zero!");
2505 // Shift the value upfront if it is even, so the LSB is one.
2506 unsigned ShAmt = d.countTrailingZeros();
2508 // TODO: For UDIV use SRL instead of SRA.
2509 SDValue Amt = DAG.getConstant(ShAmt, getShiftAmountTy(Op1.getValueType()));
2510 Op1 = DAG.getNode(ISD::SRA, dl, Op1.getValueType(), Op1, Amt);
2514 // Calculate the multiplicative inverse, using Newton's method.
2516 while ((t = d*xn) != 1)
2517 xn *= APInt(d.getBitWidth(), 2) - t;
2519 Op2 = DAG.getConstant(xn, Op1.getValueType());
2520 return DAG.getNode(ISD::MUL, dl, Op1.getValueType(), Op1, Op2);
2523 /// \brief Given an ISD::SDIV node expressing a divide by constant,
2524 /// return a DAG expression to select that will generate the same value by
2525 /// multiplying by a magic number. See:
2526 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
2527 SDValue TargetLowering::
2528 BuildSDIV(SDNode *N, SelectionDAG &DAG, bool IsAfterLegalization,
2529 std::vector<SDNode*> *Created) const {
2530 EVT VT = N->getValueType(0);
2533 // Check to see if we can do this.
2534 // FIXME: We should be more aggressive here.
2535 if (!isTypeLegal(VT))
2538 APInt d = cast<ConstantSDNode>(N->getOperand(1))->getAPIntValue();
2539 APInt::ms magics = d.magic();
2541 // Multiply the numerator (operand 0) by the magic value
2542 // FIXME: We should support doing a MUL in a wider type
2544 if (IsAfterLegalization ? isOperationLegal(ISD::MULHS, VT) :
2545 isOperationLegalOrCustom(ISD::MULHS, VT))
2546 Q = DAG.getNode(ISD::MULHS, dl, VT, N->getOperand(0),
2547 DAG.getConstant(magics.m, VT));
2548 else if (IsAfterLegalization ? isOperationLegal(ISD::SMUL_LOHI, VT) :
2549 isOperationLegalOrCustom(ISD::SMUL_LOHI, VT))
2550 Q = SDValue(DAG.getNode(ISD::SMUL_LOHI, dl, DAG.getVTList(VT, VT),
2552 DAG.getConstant(magics.m, VT)).getNode(), 1);
2554 return SDValue(); // No mulhs or equvialent
2555 // If d > 0 and m < 0, add the numerator
2556 if (d.isStrictlyPositive() && magics.m.isNegative()) {
2557 Q = DAG.getNode(ISD::ADD, dl, VT, Q, N->getOperand(0));
2559 Created->push_back(Q.getNode());
2561 // If d < 0 and m > 0, subtract the numerator.
2562 if (d.isNegative() && magics.m.isStrictlyPositive()) {
2563 Q = DAG.getNode(ISD::SUB, dl, VT, Q, N->getOperand(0));
2565 Created->push_back(Q.getNode());
2567 // Shift right algebraic if shift value is nonzero
2569 Q = DAG.getNode(ISD::SRA, dl, VT, Q,
2570 DAG.getConstant(magics.s, getShiftAmountTy(Q.getValueType())));
2572 Created->push_back(Q.getNode());
2574 // Extract the sign bit and add it to the quotient
2576 DAG.getNode(ISD::SRL, dl, VT, Q, DAG.getConstant(VT.getSizeInBits()-1,
2577 getShiftAmountTy(Q.getValueType())));
2579 Created->push_back(T.getNode());
2580 return DAG.getNode(ISD::ADD, dl, VT, Q, T);
2583 /// \brief Given an ISD::UDIV node expressing a divide by constant,
2584 /// return a DAG expression to select that will generate the same value by
2585 /// multiplying by a magic number. See:
2586 /// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
2587 SDValue TargetLowering::
2588 BuildUDIV(SDNode *N, SelectionDAG &DAG, bool IsAfterLegalization,
2589 std::vector<SDNode*> *Created) const {
2590 EVT VT = N->getValueType(0);
2593 // Check to see if we can do this.
2594 // FIXME: We should be more aggressive here.
2595 if (!isTypeLegal(VT))
2598 // FIXME: We should use a narrower constant when the upper
2599 // bits are known to be zero.
2600 const APInt &N1C = cast<ConstantSDNode>(N->getOperand(1))->getAPIntValue();
2601 APInt::mu magics = N1C.magicu();
2603 SDValue Q = N->getOperand(0);
2605 // If the divisor is even, we can avoid using the expensive fixup by shifting
2606 // the divided value upfront.
2607 if (magics.a != 0 && !N1C[0]) {
2608 unsigned Shift = N1C.countTrailingZeros();
2609 Q = DAG.getNode(ISD::SRL, dl, VT, Q,
2610 DAG.getConstant(Shift, getShiftAmountTy(Q.getValueType())));
2612 Created->push_back(Q.getNode());
2614 // Get magic number for the shifted divisor.
2615 magics = N1C.lshr(Shift).magicu(Shift);
2616 assert(magics.a == 0 && "Should use cheap fixup now");
2619 // Multiply the numerator (operand 0) by the magic value
2620 // FIXME: We should support doing a MUL in a wider type
2621 if (IsAfterLegalization ? isOperationLegal(ISD::MULHU, VT) :
2622 isOperationLegalOrCustom(ISD::MULHU, VT))
2623 Q = DAG.getNode(ISD::MULHU, dl, VT, Q, DAG.getConstant(magics.m, VT));
2624 else if (IsAfterLegalization ? isOperationLegal(ISD::UMUL_LOHI, VT) :
2625 isOperationLegalOrCustom(ISD::UMUL_LOHI, VT))
2626 Q = SDValue(DAG.getNode(ISD::UMUL_LOHI, dl, DAG.getVTList(VT, VT), Q,
2627 DAG.getConstant(magics.m, VT)).getNode(), 1);
2629 return SDValue(); // No mulhu or equvialent
2631 Created->push_back(Q.getNode());
2633 if (magics.a == 0) {
2634 assert(magics.s < N1C.getBitWidth() &&
2635 "We shouldn't generate an undefined shift!");
2636 return DAG.getNode(ISD::SRL, dl, VT, Q,
2637 DAG.getConstant(magics.s, getShiftAmountTy(Q.getValueType())));
2639 SDValue NPQ = DAG.getNode(ISD::SUB, dl, VT, N->getOperand(0), Q);
2641 Created->push_back(NPQ.getNode());
2642 NPQ = DAG.getNode(ISD::SRL, dl, VT, NPQ,
2643 DAG.getConstant(1, getShiftAmountTy(NPQ.getValueType())));
2645 Created->push_back(NPQ.getNode());
2646 NPQ = DAG.getNode(ISD::ADD, dl, VT, NPQ, Q);
2648 Created->push_back(NPQ.getNode());
2649 return DAG.getNode(ISD::SRL, dl, VT, NPQ,
2650 DAG.getConstant(magics.s-1, getShiftAmountTy(NPQ.getValueType())));