1 //===-- llvm/Target/TargetLowering.h - Target Lowering Info -----*- C++ -*-===//
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 file describes how to lower LLVM code to machine code. This has two
13 // 1. Which ValueTypes are natively supported by the target.
14 // 2. Which operations are supported for supported ValueTypes.
15 // 3. Cost thresholds for alternative implementations of certain operations.
17 // In addition it has a few other components, like information about FP
20 //===----------------------------------------------------------------------===//
22 #ifndef LLVM_TARGET_TARGETLOWERING_H
23 #define LLVM_TARGET_TARGETLOWERING_H
25 #include "llvm/CallingConv.h"
26 #include "llvm/InlineAsm.h"
27 #include "llvm/Attributes.h"
28 #include "llvm/ADT/SmallPtrSet.h"
29 #include "llvm/CodeGen/SelectionDAGNodes.h"
30 #include "llvm/CodeGen/RuntimeLibcalls.h"
31 #include "llvm/Support/DebugLoc.h"
32 #include "llvm/Target/TargetCallingConv.h"
33 #include "llvm/Target/TargetMachine.h"
45 class FunctionLoweringInfo;
46 class ImmutableCallSite;
47 class MachineBasicBlock;
48 class MachineFunction;
49 class MachineFrameInfo;
51 class MachineJumpTableInfo;
57 template<typename T> class SmallVectorImpl;
60 class TargetRegisterClass;
61 class TargetLoweringObjectFile;
64 // FIXME: should this be here?
73 TLSModel::Model getTLSModel(const GlobalValue *GV, Reloc::Model reloc);
76 //===----------------------------------------------------------------------===//
77 /// TargetLowering - This class defines information used to lower LLVM code to
78 /// legal SelectionDAG operators that the target instruction selector can accept
81 /// This class also defines callbacks that targets must implement to lower
82 /// target-specific constructs to SelectionDAG operators.
84 class TargetLowering {
85 TargetLowering(const TargetLowering&); // DO NOT IMPLEMENT
86 void operator=(const TargetLowering&); // DO NOT IMPLEMENT
88 /// LegalizeAction - This enum indicates whether operations are valid for a
89 /// target, and if not, what action should be used to make them valid.
91 Legal, // The target natively supports this operation.
92 Promote, // This operation should be executed in a larger type.
93 Expand, // Try to expand this to other ops, otherwise use a libcall.
94 Custom // Use the LowerOperation hook to implement custom lowering.
97 enum BooleanContent { // How the target represents true/false values.
98 UndefinedBooleanContent, // Only bit 0 counts, the rest can hold garbage.
99 ZeroOrOneBooleanContent, // All bits zero except for bit 0.
100 ZeroOrNegativeOneBooleanContent // All bits equal to bit 0.
103 /// NOTE: The constructor takes ownership of TLOF.
104 explicit TargetLowering(const TargetMachine &TM,
105 const TargetLoweringObjectFile *TLOF);
106 virtual ~TargetLowering();
108 const TargetMachine &getTargetMachine() const { return TM; }
109 const TargetData *getTargetData() const { return TD; }
110 const TargetLoweringObjectFile &getObjFileLowering() const { return TLOF; }
112 bool isBigEndian() const { return !IsLittleEndian; }
113 bool isLittleEndian() const { return IsLittleEndian; }
114 MVT getPointerTy() const { return PointerTy; }
115 virtual MVT getShiftAmountTy(EVT LHSTy) const;
117 /// isSelectExpensive - Return true if the select operation is expensive for
119 bool isSelectExpensive() const { return SelectIsExpensive; }
121 /// isIntDivCheap() - Return true if integer divide is usually cheaper than
122 /// a sequence of several shifts, adds, and multiplies for this target.
123 bool isIntDivCheap() const { return IntDivIsCheap; }
125 /// isPow2DivCheap() - Return true if pow2 div is cheaper than a chain of
127 bool isPow2DivCheap() const { return Pow2DivIsCheap; }
129 /// isJumpExpensive() - Return true if Flow Control is an expensive operation
130 /// that should be avoided.
131 bool isJumpExpensive() const { return JumpIsExpensive; }
133 /// getSetCCResultType - Return the ValueType of the result of SETCC
134 /// operations. Also used to obtain the target's preferred type for
135 /// the condition operand of SELECT and BRCOND nodes. In the case of
136 /// BRCOND the argument passed is MVT::Other since there are no other
137 /// operands to get a type hint from.
139 MVT::SimpleValueType getSetCCResultType(EVT VT) const;
141 /// getCmpLibcallReturnType - Return the ValueType for comparison
142 /// libcalls. Comparions libcalls include floating point comparion calls,
143 /// and Ordered/Unordered check calls on floating point numbers.
145 MVT::SimpleValueType getCmpLibcallReturnType() const;
147 /// getBooleanContents - For targets without i1 registers, this gives the
148 /// nature of the high-bits of boolean values held in types wider than i1.
149 /// "Boolean values" are special true/false values produced by nodes like
150 /// SETCC and consumed (as the condition) by nodes like SELECT and BRCOND.
151 /// Not to be confused with general values promoted from i1.
152 BooleanContent getBooleanContents() const { return BooleanContents;}
154 /// getSchedulingPreference - Return target scheduling preference.
155 Sched::Preference getSchedulingPreference() const {
156 return SchedPreferenceInfo;
159 /// getSchedulingPreference - Some scheduler, e.g. hybrid, can switch to
160 /// different scheduling heuristics for different nodes. This function returns
161 /// the preference (or none) for the given node.
162 virtual Sched::Preference getSchedulingPreference(SDNode *N) const {
166 /// getRegClassFor - Return the register class that should be used for the
167 /// specified value type.
168 virtual TargetRegisterClass *getRegClassFor(EVT VT) const {
169 assert(VT.isSimple() && "getRegClassFor called on illegal type!");
170 TargetRegisterClass *RC = RegClassForVT[VT.getSimpleVT().SimpleTy];
171 assert(RC && "This value type is not natively supported!");
175 /// getRepRegClassFor - Return the 'representative' register class for the
176 /// specified value type. The 'representative' register class is the largest
177 /// legal super-reg register class for the register class of the value type.
178 /// For example, on i386 the rep register class for i8, i16, and i32 are GR32;
179 /// while the rep register class is GR64 on x86_64.
180 virtual const TargetRegisterClass *getRepRegClassFor(EVT VT) const {
181 assert(VT.isSimple() && "getRepRegClassFor called on illegal type!");
182 const TargetRegisterClass *RC = RepRegClassForVT[VT.getSimpleVT().SimpleTy];
186 /// getRepRegClassCostFor - Return the cost of the 'representative' register
187 /// class for the specified value type.
188 virtual uint8_t getRepRegClassCostFor(EVT VT) const {
189 assert(VT.isSimple() && "getRepRegClassCostFor called on illegal type!");
190 return RepRegClassCostForVT[VT.getSimpleVT().SimpleTy];
193 /// isTypeLegal - Return true if the target has native support for the
194 /// specified value type. This means that it has a register that directly
195 /// holds it without promotions or expansions.
196 bool isTypeLegal(EVT VT) const {
197 assert(!VT.isSimple() ||
198 (unsigned)VT.getSimpleVT().SimpleTy < array_lengthof(RegClassForVT));
199 return VT.isSimple() && RegClassForVT[VT.getSimpleVT().SimpleTy] != 0;
202 class ValueTypeActionImpl {
203 /// ValueTypeActions - For each value type, keep a LegalizeAction enum
204 /// that indicates how instruction selection should deal with the type.
205 uint8_t ValueTypeActions[MVT::LAST_VALUETYPE];
207 LegalizeAction getExtendedTypeAction(EVT VT) const {
208 // Handle non-vector integers.
209 if (!VT.isVector()) {
210 assert(VT.isInteger() && "Unsupported extended type!");
211 unsigned BitSize = VT.getSizeInBits();
212 // First promote to a power-of-two size, then expand if necessary.
213 if (BitSize < 8 || !isPowerOf2_32(BitSize))
218 // Vectors with only one element are always scalarized.
219 if (VT.getVectorNumElements() == 1)
222 // Vectors with a number of elements that is not a power of two are always
223 // widened, for example <3 x float> -> <4 x float>.
224 if (!VT.isPow2VectorType())
227 // Vectors with a crazy element type are always expanded, for example
228 // <4 x i2> is expanded into two vectors of type <2 x i2>.
229 if (!VT.getVectorElementType().isSimple())
232 // If this type is smaller than a legal vector type then widen it,
233 // otherwise expand it. E.g. <2 x float> -> <4 x float>.
234 MVT EltType = VT.getVectorElementType().getSimpleVT();
235 unsigned NumElts = VT.getVectorNumElements();
237 // Round up to the next power of 2.
238 NumElts = (unsigned)NextPowerOf2(NumElts);
240 // If there is no simple vector type with this many elements then there
241 // cannot be a larger legal vector type. Note that this assumes that
242 // there are no skipped intermediate vector types in the simple types.
243 MVT LargerVector = MVT::getVectorVT(EltType, NumElts);
244 if (LargerVector == MVT())
247 // If this type is legal then widen the vector.
248 if (getTypeAction(LargerVector) == Legal)
253 ValueTypeActionImpl() {
254 std::fill(ValueTypeActions, array_endof(ValueTypeActions), 0);
257 LegalizeAction getTypeAction(EVT VT) const {
258 if (!VT.isExtended())
259 return getTypeAction(VT.getSimpleVT());
260 return getExtendedTypeAction(VT);
263 LegalizeAction getTypeAction(MVT VT) const {
264 return (LegalizeAction)ValueTypeActions[VT.SimpleTy];
267 void setTypeAction(EVT VT, LegalizeAction Action) {
268 unsigned I = VT.getSimpleVT().SimpleTy;
269 ValueTypeActions[I] = Action;
273 const ValueTypeActionImpl &getValueTypeActions() const {
274 return ValueTypeActions;
277 /// getTypeAction - Return how we should legalize values of this type, either
278 /// it is already legal (return 'Legal') or we need to promote it to a larger
279 /// type (return 'Promote'), or we need to expand it into multiple registers
280 /// of smaller integer type (return 'Expand'). 'Custom' is not an option.
281 LegalizeAction getTypeAction(EVT VT) const {
282 return ValueTypeActions.getTypeAction(VT);
284 LegalizeAction getTypeAction(MVT VT) const {
285 return ValueTypeActions.getTypeAction(VT);
288 /// getTypeToTransformTo - For types supported by the target, this is an
289 /// identity function. For types that must be promoted to larger types, this
290 /// returns the larger type to promote to. For integer types that are larger
291 /// than the largest integer register, this contains one step in the expansion
292 /// to get to the smaller register. For illegal floating point types, this
293 /// returns the integer type to transform to.
294 EVT getTypeToTransformTo(LLVMContext &Context, EVT VT) const {
296 assert((unsigned)VT.getSimpleVT().SimpleTy <
297 array_lengthof(TransformToType));
298 EVT NVT = TransformToType[VT.getSimpleVT().SimpleTy];
299 assert(getTypeAction(NVT) != Promote &&
300 "Promote may not follow Expand or Promote");
305 EVT NVT = VT.getPow2VectorType(Context);
307 // Vector length is a power of 2 - split to half the size.
308 unsigned NumElts = VT.getVectorNumElements();
309 EVT EltVT = VT.getVectorElementType();
310 return (NumElts == 1) ?
311 EltVT : EVT::getVectorVT(Context, EltVT, NumElts / 2);
313 // Promote to a power of two size, avoiding multi-step promotion.
314 return getTypeAction(NVT) == Promote ?
315 getTypeToTransformTo(Context, NVT) : NVT;
316 } else if (VT.isInteger()) {
317 EVT NVT = VT.getRoundIntegerType(Context);
318 if (NVT == VT) // Size is a power of two - expand to half the size.
319 return EVT::getIntegerVT(Context, VT.getSizeInBits() / 2);
321 // Promote to a power of two size, avoiding multi-step promotion.
322 return getTypeAction(NVT) == Promote ?
323 getTypeToTransformTo(Context, NVT) : NVT;
325 assert(0 && "Unsupported extended type!");
326 return MVT(MVT::Other); // Not reached
329 /// getTypeToExpandTo - For types supported by the target, this is an
330 /// identity function. For types that must be expanded (i.e. integer types
331 /// that are larger than the largest integer register or illegal floating
332 /// point types), this returns the largest legal type it will be expanded to.
333 EVT getTypeToExpandTo(LLVMContext &Context, EVT VT) const {
334 assert(!VT.isVector());
336 switch (getTypeAction(VT)) {
340 VT = getTypeToTransformTo(Context, VT);
343 assert(false && "Type is not legal nor is it to be expanded!");
350 /// getVectorTypeBreakdown - Vector types are broken down into some number of
351 /// legal first class types. For example, EVT::v8f32 maps to 2 EVT::v4f32
352 /// with Altivec or SSE1, or 8 promoted EVT::f64 values with the X86 FP stack.
353 /// Similarly, EVT::v2i64 turns into 4 EVT::i32 values with both PPC and X86.
355 /// This method returns the number of registers needed, and the VT for each
356 /// register. It also returns the VT and quantity of the intermediate values
357 /// before they are promoted/expanded.
359 unsigned getVectorTypeBreakdown(LLVMContext &Context, EVT VT,
361 unsigned &NumIntermediates,
362 EVT &RegisterVT) const;
364 /// getTgtMemIntrinsic: Given an intrinsic, checks if on the target the
365 /// intrinsic will need to map to a MemIntrinsicNode (touches memory). If
366 /// this is the case, it returns true and store the intrinsic
367 /// information into the IntrinsicInfo that was passed to the function.
368 struct IntrinsicInfo {
369 unsigned opc; // target opcode
370 EVT memVT; // memory VT
371 const Value* ptrVal; // value representing memory location
372 int offset; // offset off of ptrVal
373 unsigned align; // alignment
374 bool vol; // is volatile?
375 bool readMem; // reads memory?
376 bool writeMem; // writes memory?
379 virtual bool getTgtMemIntrinsic(IntrinsicInfo &Info,
380 const CallInst &I, unsigned Intrinsic) const {
384 /// isFPImmLegal - Returns true if the target can instruction select the
385 /// specified FP immediate natively. If false, the legalizer will materialize
386 /// the FP immediate as a load from a constant pool.
387 virtual bool isFPImmLegal(const APFloat &Imm, EVT VT) const {
391 /// isShuffleMaskLegal - Targets can use this to indicate that they only
392 /// support *some* VECTOR_SHUFFLE operations, those with specific masks.
393 /// By default, if a target supports the VECTOR_SHUFFLE node, all mask values
394 /// are assumed to be legal.
395 virtual bool isShuffleMaskLegal(const SmallVectorImpl<int> &Mask,
400 /// canOpTrap - Returns true if the operation can trap for the value type.
401 /// VT must be a legal type. By default, we optimistically assume most
402 /// operations don't trap except for divide and remainder.
403 virtual bool canOpTrap(unsigned Op, EVT VT) const;
405 /// isVectorClearMaskLegal - Similar to isShuffleMaskLegal. This is
406 /// used by Targets can use this to indicate if there is a suitable
407 /// VECTOR_SHUFFLE that can be used to replace a VAND with a constant
409 virtual bool isVectorClearMaskLegal(const SmallVectorImpl<int> &Mask,
414 /// getOperationAction - Return how this operation should be treated: either
415 /// it is legal, needs to be promoted to a larger size, needs to be
416 /// expanded to some other code sequence, or the target has a custom expander
418 LegalizeAction getOperationAction(unsigned Op, EVT VT) const {
419 if (VT.isExtended()) return Expand;
420 assert(Op < array_lengthof(OpActions[0]) && "Table isn't big enough!");
421 unsigned I = (unsigned) VT.getSimpleVT().SimpleTy;
422 return (LegalizeAction)OpActions[I][Op];
425 /// isOperationLegalOrCustom - Return true if the specified operation is
426 /// legal on this target or can be made legal with custom lowering. This
427 /// is used to help guide high-level lowering decisions.
428 bool isOperationLegalOrCustom(unsigned Op, EVT VT) const {
429 return (VT == MVT::Other || isTypeLegal(VT)) &&
430 (getOperationAction(Op, VT) == Legal ||
431 getOperationAction(Op, VT) == Custom);
434 /// isOperationLegal - Return true if the specified operation is legal on this
436 bool isOperationLegal(unsigned Op, EVT VT) const {
437 return (VT == MVT::Other || isTypeLegal(VT)) &&
438 getOperationAction(Op, VT) == Legal;
441 /// getLoadExtAction - Return how this load with extension should be treated:
442 /// either it is legal, needs to be promoted to a larger size, needs to be
443 /// expanded to some other code sequence, or the target has a custom expander
445 LegalizeAction getLoadExtAction(unsigned ExtType, EVT VT) const {
446 assert(ExtType < ISD::LAST_LOADEXT_TYPE &&
447 VT.getSimpleVT() < MVT::LAST_VALUETYPE &&
448 "Table isn't big enough!");
449 return (LegalizeAction)LoadExtActions[VT.getSimpleVT().SimpleTy][ExtType];
452 /// isLoadExtLegal - Return true if the specified load with extension is legal
454 bool isLoadExtLegal(unsigned ExtType, EVT VT) const {
455 return VT.isSimple() &&
456 (getLoadExtAction(ExtType, VT) == Legal ||
457 getLoadExtAction(ExtType, VT) == Custom);
460 /// getTruncStoreAction - Return how this store with truncation should be
461 /// treated: either it is legal, needs to be promoted to a larger size, needs
462 /// to be expanded to some other code sequence, or the target has a custom
464 LegalizeAction getTruncStoreAction(EVT ValVT, EVT MemVT) const {
465 assert(ValVT.getSimpleVT() < MVT::LAST_VALUETYPE &&
466 MemVT.getSimpleVT() < MVT::LAST_VALUETYPE &&
467 "Table isn't big enough!");
468 return (LegalizeAction)TruncStoreActions[ValVT.getSimpleVT().SimpleTy]
469 [MemVT.getSimpleVT().SimpleTy];
472 /// isTruncStoreLegal - Return true if the specified store with truncation is
473 /// legal on this target.
474 bool isTruncStoreLegal(EVT ValVT, EVT MemVT) const {
475 return isTypeLegal(ValVT) && MemVT.isSimple() &&
476 (getTruncStoreAction(ValVT, MemVT) == Legal ||
477 getTruncStoreAction(ValVT, MemVT) == Custom);
480 /// getIndexedLoadAction - Return how the indexed load should be treated:
481 /// either it is legal, needs to be promoted to a larger size, needs to be
482 /// expanded to some other code sequence, or the target has a custom expander
485 getIndexedLoadAction(unsigned IdxMode, EVT VT) const {
486 assert(IdxMode < ISD::LAST_INDEXED_MODE &&
487 VT.getSimpleVT() < MVT::LAST_VALUETYPE &&
488 "Table isn't big enough!");
489 unsigned Ty = (unsigned)VT.getSimpleVT().SimpleTy;
490 return (LegalizeAction)((IndexedModeActions[Ty][IdxMode] & 0xf0) >> 4);
493 /// isIndexedLoadLegal - Return true if the specified indexed load is legal
495 bool isIndexedLoadLegal(unsigned IdxMode, EVT VT) const {
496 return VT.isSimple() &&
497 (getIndexedLoadAction(IdxMode, VT) == Legal ||
498 getIndexedLoadAction(IdxMode, VT) == Custom);
501 /// getIndexedStoreAction - Return how the indexed store should be treated:
502 /// either it is legal, needs to be promoted to a larger size, needs to be
503 /// expanded to some other code sequence, or the target has a custom expander
506 getIndexedStoreAction(unsigned IdxMode, EVT VT) const {
507 assert(IdxMode < ISD::LAST_INDEXED_MODE &&
508 VT.getSimpleVT() < MVT::LAST_VALUETYPE &&
509 "Table isn't big enough!");
510 unsigned Ty = (unsigned)VT.getSimpleVT().SimpleTy;
511 return (LegalizeAction)(IndexedModeActions[Ty][IdxMode] & 0x0f);
514 /// isIndexedStoreLegal - Return true if the specified indexed load is legal
516 bool isIndexedStoreLegal(unsigned IdxMode, EVT VT) const {
517 return VT.isSimple() &&
518 (getIndexedStoreAction(IdxMode, VT) == Legal ||
519 getIndexedStoreAction(IdxMode, VT) == Custom);
522 /// getCondCodeAction - Return how the condition code should be treated:
523 /// either it is legal, needs to be expanded to some other code sequence,
524 /// or the target has a custom expander for it.
526 getCondCodeAction(ISD::CondCode CC, EVT VT) const {
527 assert((unsigned)CC < array_lengthof(CondCodeActions) &&
528 (unsigned)VT.getSimpleVT().SimpleTy < sizeof(CondCodeActions[0])*4 &&
529 "Table isn't big enough!");
530 LegalizeAction Action = (LegalizeAction)
531 ((CondCodeActions[CC] >> (2*VT.getSimpleVT().SimpleTy)) & 3);
532 assert(Action != Promote && "Can't promote condition code!");
536 /// isCondCodeLegal - Return true if the specified condition code is legal
538 bool isCondCodeLegal(ISD::CondCode CC, EVT VT) const {
539 return getCondCodeAction(CC, VT) == Legal ||
540 getCondCodeAction(CC, VT) == Custom;
544 /// getTypeToPromoteTo - If the action for this operation is to promote, this
545 /// method returns the ValueType to promote to.
546 EVT getTypeToPromoteTo(unsigned Op, EVT VT) const {
547 assert(getOperationAction(Op, VT) == Promote &&
548 "This operation isn't promoted!");
550 // See if this has an explicit type specified.
551 std::map<std::pair<unsigned, MVT::SimpleValueType>,
552 MVT::SimpleValueType>::const_iterator PTTI =
553 PromoteToType.find(std::make_pair(Op, VT.getSimpleVT().SimpleTy));
554 if (PTTI != PromoteToType.end()) return PTTI->second;
556 assert((VT.isInteger() || VT.isFloatingPoint()) &&
557 "Cannot autopromote this type, add it with AddPromotedToType.");
561 NVT = (MVT::SimpleValueType)(NVT.getSimpleVT().SimpleTy+1);
562 assert(NVT.isInteger() == VT.isInteger() && NVT != MVT::isVoid &&
563 "Didn't find type to promote to!");
564 } while (!isTypeLegal(NVT) ||
565 getOperationAction(Op, NVT) == Promote);
569 /// getValueType - Return the EVT corresponding to this LLVM type.
570 /// This is fixed by the LLVM operations except for the pointer size. If
571 /// AllowUnknown is true, this will return MVT::Other for types with no EVT
572 /// counterpart (e.g. structs), otherwise it will assert.
573 EVT getValueType(const Type *Ty, bool AllowUnknown = false) const {
574 EVT VT = EVT::getEVT(Ty, AllowUnknown);
575 return VT == MVT::iPTR ? PointerTy : VT;
578 /// getByValTypeAlignment - Return the desired alignment for ByVal aggregate
579 /// function arguments in the caller parameter area. This is the actual
580 /// alignment, not its logarithm.
581 virtual unsigned getByValTypeAlignment(const Type *Ty) const;
583 /// getRegisterType - Return the type of registers that this ValueType will
584 /// eventually require.
585 EVT getRegisterType(MVT VT) const {
586 assert((unsigned)VT.SimpleTy < array_lengthof(RegisterTypeForVT));
587 return RegisterTypeForVT[VT.SimpleTy];
590 /// getRegisterType - Return the type of registers that this ValueType will
591 /// eventually require.
592 EVT getRegisterType(LLVMContext &Context, EVT VT) const {
594 assert((unsigned)VT.getSimpleVT().SimpleTy <
595 array_lengthof(RegisterTypeForVT));
596 return RegisterTypeForVT[VT.getSimpleVT().SimpleTy];
600 unsigned NumIntermediates;
601 (void)getVectorTypeBreakdown(Context, VT, VT1,
602 NumIntermediates, RegisterVT);
605 if (VT.isInteger()) {
606 return getRegisterType(Context, getTypeToTransformTo(Context, VT));
608 assert(0 && "Unsupported extended type!");
609 return EVT(MVT::Other); // Not reached
612 /// getNumRegisters - Return the number of registers that this ValueType will
613 /// eventually require. This is one for any types promoted to live in larger
614 /// registers, but may be more than one for types (like i64) that are split
615 /// into pieces. For types like i140, which are first promoted then expanded,
616 /// it is the number of registers needed to hold all the bits of the original
617 /// type. For an i140 on a 32 bit machine this means 5 registers.
618 unsigned getNumRegisters(LLVMContext &Context, EVT VT) const {
620 assert((unsigned)VT.getSimpleVT().SimpleTy <
621 array_lengthof(NumRegistersForVT));
622 return NumRegistersForVT[VT.getSimpleVT().SimpleTy];
626 unsigned NumIntermediates;
627 return getVectorTypeBreakdown(Context, VT, VT1, NumIntermediates, VT2);
629 if (VT.isInteger()) {
630 unsigned BitWidth = VT.getSizeInBits();
631 unsigned RegWidth = getRegisterType(Context, VT).getSizeInBits();
632 return (BitWidth + RegWidth - 1) / RegWidth;
634 assert(0 && "Unsupported extended type!");
635 return 0; // Not reached
638 /// ShouldShrinkFPConstant - If true, then instruction selection should
639 /// seek to shrink the FP constant of the specified type to a smaller type
640 /// in order to save space and / or reduce runtime.
641 virtual bool ShouldShrinkFPConstant(EVT VT) const { return true; }
643 /// hasTargetDAGCombine - If true, the target has custom DAG combine
644 /// transformations that it can perform for the specified node.
645 bool hasTargetDAGCombine(ISD::NodeType NT) const {
646 assert(unsigned(NT >> 3) < array_lengthof(TargetDAGCombineArray));
647 return TargetDAGCombineArray[NT >> 3] & (1 << (NT&7));
650 /// This function returns the maximum number of store operations permitted
651 /// to replace a call to llvm.memset. The value is set by the target at the
652 /// performance threshold for such a replacement. If OptSize is true,
653 /// return the limit for functions that have OptSize attribute.
654 /// @brief Get maximum # of store operations permitted for llvm.memset
655 unsigned getMaxStoresPerMemset(bool OptSize) const {
656 return OptSize ? maxStoresPerMemsetOptSize : maxStoresPerMemset;
659 /// This function returns the maximum number of store operations permitted
660 /// to replace a call to llvm.memcpy. The value is set by the target at the
661 /// performance threshold for such a replacement. If OptSize is true,
662 /// return the limit for functions that have OptSize attribute.
663 /// @brief Get maximum # of store operations permitted for llvm.memcpy
664 unsigned getMaxStoresPerMemcpy(bool OptSize) const {
665 return OptSize ? maxStoresPerMemcpyOptSize : maxStoresPerMemcpy;
668 /// This function returns the maximum number of store operations permitted
669 /// to replace a call to llvm.memmove. The value is set by the target at the
670 /// performance threshold for such a replacement. If OptSize is true,
671 /// return the limit for functions that have OptSize attribute.
672 /// @brief Get maximum # of store operations permitted for llvm.memmove
673 unsigned getMaxStoresPerMemmove(bool OptSize) const {
674 return OptSize ? maxStoresPerMemmoveOptSize : maxStoresPerMemmove;
677 /// This function returns true if the target allows unaligned memory accesses.
678 /// of the specified type. This is used, for example, in situations where an
679 /// array copy/move/set is converted to a sequence of store operations. It's
680 /// use helps to ensure that such replacements don't generate code that causes
681 /// an alignment error (trap) on the target machine.
682 /// @brief Determine if the target supports unaligned memory accesses.
683 virtual bool allowsUnalignedMemoryAccesses(EVT VT) const {
687 /// This function returns true if the target would benefit from code placement
689 /// @brief Determine if the target should perform code placement optimization.
690 bool shouldOptimizeCodePlacement() const {
691 return benefitFromCodePlacementOpt;
694 /// getOptimalMemOpType - Returns the target specific optimal type for load
695 /// and store operations as a result of memset, memcpy, and memmove
696 /// lowering. If DstAlign is zero that means it's safe to destination
697 /// alignment can satisfy any constraint. Similarly if SrcAlign is zero it
698 /// means there isn't a need to check it against alignment requirement,
699 /// probably because the source does not need to be loaded. If
700 /// 'NonScalarIntSafe' is true, that means it's safe to return a
701 /// non-scalar-integer type, e.g. empty string source, constant, or loaded
702 /// from memory. 'MemcpyStrSrc' indicates whether the memcpy source is
703 /// constant so it does not need to be loaded.
704 /// It returns EVT::Other if the type should be determined using generic
705 /// target-independent logic.
706 virtual EVT getOptimalMemOpType(uint64_t Size,
707 unsigned DstAlign, unsigned SrcAlign,
708 bool NonScalarIntSafe, bool MemcpyStrSrc,
709 MachineFunction &MF) const {
713 /// usesUnderscoreSetJmp - Determine if we should use _setjmp or setjmp
714 /// to implement llvm.setjmp.
715 bool usesUnderscoreSetJmp() const {
716 return UseUnderscoreSetJmp;
719 /// usesUnderscoreLongJmp - Determine if we should use _longjmp or longjmp
720 /// to implement llvm.longjmp.
721 bool usesUnderscoreLongJmp() const {
722 return UseUnderscoreLongJmp;
725 /// getStackPointerRegisterToSaveRestore - If a physical register, this
726 /// specifies the register that llvm.savestack/llvm.restorestack should save
728 unsigned getStackPointerRegisterToSaveRestore() const {
729 return StackPointerRegisterToSaveRestore;
732 /// getExceptionAddressRegister - If a physical register, this returns
733 /// the register that receives the exception address on entry to a landing
735 unsigned getExceptionAddressRegister() const {
736 return ExceptionPointerRegister;
739 /// getExceptionSelectorRegister - If a physical register, this returns
740 /// the register that receives the exception typeid on entry to a landing
742 unsigned getExceptionSelectorRegister() const {
743 return ExceptionSelectorRegister;
746 /// getJumpBufSize - returns the target's jmp_buf size in bytes (if never
747 /// set, the default is 200)
748 unsigned getJumpBufSize() const {
752 /// getJumpBufAlignment - returns the target's jmp_buf alignment in bytes
753 /// (if never set, the default is 0)
754 unsigned getJumpBufAlignment() const {
755 return JumpBufAlignment;
758 /// getMinStackArgumentAlignment - return the minimum stack alignment of an
760 unsigned getMinStackArgumentAlignment() const {
761 return MinStackArgumentAlignment;
764 /// getPrefLoopAlignment - return the preferred loop alignment.
766 unsigned getPrefLoopAlignment() const {
767 return PrefLoopAlignment;
770 /// getShouldFoldAtomicFences - return whether the combiner should fold
771 /// fence MEMBARRIER instructions into the atomic intrinsic instructions.
773 bool getShouldFoldAtomicFences() const {
774 return ShouldFoldAtomicFences;
777 /// getPreIndexedAddressParts - returns true by value, base pointer and
778 /// offset pointer and addressing mode by reference if the node's address
779 /// can be legally represented as pre-indexed load / store address.
780 virtual bool getPreIndexedAddressParts(SDNode *N, SDValue &Base,
782 ISD::MemIndexedMode &AM,
783 SelectionDAG &DAG) const {
787 /// getPostIndexedAddressParts - returns true by value, base pointer and
788 /// offset pointer and addressing mode by reference if this node can be
789 /// combined with a load / store to form a post-indexed load / store.
790 virtual bool getPostIndexedAddressParts(SDNode *N, SDNode *Op,
791 SDValue &Base, SDValue &Offset,
792 ISD::MemIndexedMode &AM,
793 SelectionDAG &DAG) const {
797 /// getJumpTableEncoding - Return the entry encoding for a jump table in the
798 /// current function. The returned value is a member of the
799 /// MachineJumpTableInfo::JTEntryKind enum.
800 virtual unsigned getJumpTableEncoding() const;
802 virtual const MCExpr *
803 LowerCustomJumpTableEntry(const MachineJumpTableInfo *MJTI,
804 const MachineBasicBlock *MBB, unsigned uid,
805 MCContext &Ctx) const {
806 assert(0 && "Need to implement this hook if target has custom JTIs");
810 /// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
812 virtual SDValue getPICJumpTableRelocBase(SDValue Table,
813 SelectionDAG &DAG) const;
815 /// getPICJumpTableRelocBaseExpr - This returns the relocation base for the
816 /// given PIC jumptable, the same as getPICJumpTableRelocBase, but as an
818 virtual const MCExpr *
819 getPICJumpTableRelocBaseExpr(const MachineFunction *MF,
820 unsigned JTI, MCContext &Ctx) const;
822 /// isOffsetFoldingLegal - Return true if folding a constant offset
823 /// with the given GlobalAddress is legal. It is frequently not legal in
824 /// PIC relocation models.
825 virtual bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const;
827 /// getFunctionAlignment - Return the Log2 alignment of this function.
828 virtual unsigned getFunctionAlignment(const Function *) const = 0;
830 /// getStackCookieLocation - Return true if the target stores stack
831 /// protector cookies at a fixed offset in some non-standard address
832 /// space, and populates the address space and offset as
834 virtual bool getStackCookieLocation(unsigned &AddressSpace, unsigned &Offset) const {
838 /// getMaximalGlobalOffset - Returns the maximal possible offset which can be
839 /// used for loads / stores from the global.
840 virtual unsigned getMaximalGlobalOffset() const {
844 //===--------------------------------------------------------------------===//
845 // TargetLowering Optimization Methods
848 /// TargetLoweringOpt - A convenience struct that encapsulates a DAG, and two
849 /// SDValues for returning information from TargetLowering to its clients
850 /// that want to combine
851 struct TargetLoweringOpt {
858 explicit TargetLoweringOpt(SelectionDAG &InDAG,
860 DAG(InDAG), LegalTys(LT), LegalOps(LO) {}
862 bool LegalTypes() const { return LegalTys; }
863 bool LegalOperations() const { return LegalOps; }
865 bool CombineTo(SDValue O, SDValue N) {
871 /// ShrinkDemandedConstant - Check to see if the specified operand of the
872 /// specified instruction is a constant integer. If so, check to see if
873 /// there are any bits set in the constant that are not demanded. If so,
874 /// shrink the constant and return true.
875 bool ShrinkDemandedConstant(SDValue Op, const APInt &Demanded);
877 /// ShrinkDemandedOp - Convert x+y to (VT)((SmallVT)x+(SmallVT)y) if the
878 /// casts are free. This uses isZExtFree and ZERO_EXTEND for the widening
879 /// cast, but it could be generalized for targets with other types of
880 /// implicit widening casts.
881 bool ShrinkDemandedOp(SDValue Op, unsigned BitWidth, const APInt &Demanded,
885 /// SimplifyDemandedBits - Look at Op. At this point, we know that only the
886 /// DemandedMask bits of the result of Op are ever used downstream. If we can
887 /// use this information to simplify Op, create a new simplified DAG node and
888 /// return true, returning the original and new nodes in Old and New.
889 /// Otherwise, analyze the expression and return a mask of KnownOne and
890 /// KnownZero bits for the expression (used to simplify the caller).
891 /// The KnownZero/One bits may only be accurate for those bits in the
893 bool SimplifyDemandedBits(SDValue Op, const APInt &DemandedMask,
894 APInt &KnownZero, APInt &KnownOne,
895 TargetLoweringOpt &TLO, unsigned Depth = 0) const;
897 /// computeMaskedBitsForTargetNode - Determine which of the bits specified in
898 /// Mask are known to be either zero or one and return them in the
899 /// KnownZero/KnownOne bitsets.
900 virtual void computeMaskedBitsForTargetNode(const SDValue Op,
904 const SelectionDAG &DAG,
905 unsigned Depth = 0) const;
907 /// ComputeNumSignBitsForTargetNode - This method can be implemented by
908 /// targets that want to expose additional information about sign bits to the
910 virtual unsigned ComputeNumSignBitsForTargetNode(SDValue Op,
911 unsigned Depth = 0) const;
913 struct DAGCombinerInfo {
914 void *DC; // The DAG Combiner object.
916 bool BeforeLegalizeOps;
917 bool CalledByLegalizer;
921 DAGCombinerInfo(SelectionDAG &dag, bool bl, bool blo, bool cl, void *dc)
922 : DC(dc), BeforeLegalize(bl), BeforeLegalizeOps(blo),
923 CalledByLegalizer(cl), DAG(dag) {}
925 bool isBeforeLegalize() const { return BeforeLegalize; }
926 bool isBeforeLegalizeOps() const { return BeforeLegalizeOps; }
927 bool isCalledByLegalizer() const { return CalledByLegalizer; }
929 void AddToWorklist(SDNode *N);
930 SDValue CombineTo(SDNode *N, const std::vector<SDValue> &To,
932 SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true);
933 SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo = true);
935 void CommitTargetLoweringOpt(const TargetLoweringOpt &TLO);
938 /// SimplifySetCC - Try to simplify a setcc built with the specified operands
939 /// and cc. If it is unable to simplify it, return a null SDValue.
940 SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
941 ISD::CondCode Cond, bool foldBooleans,
942 DAGCombinerInfo &DCI, DebugLoc dl) const;
944 /// isGAPlusOffset - Returns true (and the GlobalValue and the offset) if the
945 /// node is a GlobalAddress + offset.
947 isGAPlusOffset(SDNode *N, const GlobalValue* &GA, int64_t &Offset) const;
949 /// PerformDAGCombine - This method will be invoked for all target nodes and
950 /// for any target-independent nodes that the target has registered with
953 /// The semantics are as follows:
955 /// SDValue.Val == 0 - No change was made
956 /// SDValue.Val == N - N was replaced, is dead, and is already handled.
957 /// otherwise - N should be replaced by the returned Operand.
959 /// In addition, methods provided by DAGCombinerInfo may be used to perform
960 /// more complex transformations.
962 virtual SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const;
964 /// isTypeDesirableForOp - Return true if the target has native support for
965 /// the specified value type and it is 'desirable' to use the type for the
966 /// given node type. e.g. On x86 i16 is legal, but undesirable since i16
967 /// instruction encodings are longer and some i16 instructions are slow.
968 virtual bool isTypeDesirableForOp(unsigned Opc, EVT VT) const {
969 // By default, assume all legal types are desirable.
970 return isTypeLegal(VT);
973 /// isDesirableToPromoteOp - Return true if it is profitable for dag combiner
974 /// to transform a floating point op of specified opcode to a equivalent op of
975 /// an integer type. e.g. f32 load -> i32 load can be profitable on ARM.
976 virtual bool isDesirableToTransformToIntegerOp(unsigned Opc, EVT VT) const {
980 /// IsDesirableToPromoteOp - This method query the target whether it is
981 /// beneficial for dag combiner to promote the specified node. If true, it
982 /// should return the desired promotion type by reference.
983 virtual bool IsDesirableToPromoteOp(SDValue Op, EVT &PVT) const {
987 //===--------------------------------------------------------------------===//
988 // TargetLowering Configuration Methods - These methods should be invoked by
989 // the derived class constructor to configure this object for the target.
993 /// setBooleanContents - Specify how the target extends the result of a
994 /// boolean value from i1 to a wider type. See getBooleanContents.
995 void setBooleanContents(BooleanContent Ty) { BooleanContents = Ty; }
997 /// setSchedulingPreference - Specify the target scheduling preference.
998 void setSchedulingPreference(Sched::Preference Pref) {
999 SchedPreferenceInfo = Pref;
1002 /// setUseUnderscoreSetJmp - Indicate whether this target prefers to
1003 /// use _setjmp to implement llvm.setjmp or the non _ version.
1004 /// Defaults to false.
1005 void setUseUnderscoreSetJmp(bool Val) {
1006 UseUnderscoreSetJmp = Val;
1009 /// setUseUnderscoreLongJmp - Indicate whether this target prefers to
1010 /// use _longjmp to implement llvm.longjmp or the non _ version.
1011 /// Defaults to false.
1012 void setUseUnderscoreLongJmp(bool Val) {
1013 UseUnderscoreLongJmp = Val;
1016 /// setStackPointerRegisterToSaveRestore - If set to a physical register, this
1017 /// specifies the register that llvm.savestack/llvm.restorestack should save
1019 void setStackPointerRegisterToSaveRestore(unsigned R) {
1020 StackPointerRegisterToSaveRestore = R;
1023 /// setExceptionPointerRegister - If set to a physical register, this sets
1024 /// the register that receives the exception address on entry to a landing
1026 void setExceptionPointerRegister(unsigned R) {
1027 ExceptionPointerRegister = R;
1030 /// setExceptionSelectorRegister - If set to a physical register, this sets
1031 /// the register that receives the exception typeid on entry to a landing
1033 void setExceptionSelectorRegister(unsigned R) {
1034 ExceptionSelectorRegister = R;
1037 /// SelectIsExpensive - Tells the code generator not to expand operations
1038 /// into sequences that use the select operations if possible.
1039 void setSelectIsExpensive(bool isExpensive = true) {
1040 SelectIsExpensive = isExpensive;
1043 /// JumpIsExpensive - Tells the code generator not to expand sequence of
1044 /// operations into a seperate sequences that increases the amount of
1046 void setJumpIsExpensive(bool isExpensive = true) {
1047 JumpIsExpensive = isExpensive;
1050 /// setIntDivIsCheap - Tells the code generator that integer divide is
1051 /// expensive, and if possible, should be replaced by an alternate sequence
1052 /// of instructions not containing an integer divide.
1053 void setIntDivIsCheap(bool isCheap = true) { IntDivIsCheap = isCheap; }
1055 /// setPow2DivIsCheap - Tells the code generator that it shouldn't generate
1056 /// srl/add/sra for a signed divide by power of two, and let the target handle
1058 void setPow2DivIsCheap(bool isCheap = true) { Pow2DivIsCheap = isCheap; }
1060 /// addRegisterClass - Add the specified register class as an available
1061 /// regclass for the specified value type. This indicates the selector can
1062 /// handle values of that class natively.
1063 void addRegisterClass(EVT VT, TargetRegisterClass *RC) {
1064 assert((unsigned)VT.getSimpleVT().SimpleTy < array_lengthof(RegClassForVT));
1065 AvailableRegClasses.push_back(std::make_pair(VT, RC));
1066 RegClassForVT[VT.getSimpleVT().SimpleTy] = RC;
1069 /// findRepresentativeClass - Return the largest legal super-reg register class
1070 /// of the register class for the specified type and its associated "cost".
1071 virtual std::pair<const TargetRegisterClass*, uint8_t>
1072 findRepresentativeClass(EVT VT) const;
1074 /// computeRegisterProperties - Once all of the register classes are added,
1075 /// this allows us to compute derived properties we expose.
1076 void computeRegisterProperties();
1078 /// setOperationAction - Indicate that the specified operation does not work
1079 /// with the specified type and indicate what to do about it.
1080 void setOperationAction(unsigned Op, MVT VT,
1081 LegalizeAction Action) {
1082 assert(Op < array_lengthof(OpActions[0]) && "Table isn't big enough!");
1083 OpActions[(unsigned)VT.SimpleTy][Op] = (uint8_t)Action;
1086 /// setLoadExtAction - Indicate that the specified load with extension does
1087 /// not work with the specified type and indicate what to do about it.
1088 void setLoadExtAction(unsigned ExtType, MVT VT,
1089 LegalizeAction Action) {
1090 assert(ExtType < ISD::LAST_LOADEXT_TYPE && VT < MVT::LAST_VALUETYPE &&
1091 "Table isn't big enough!");
1092 LoadExtActions[VT.SimpleTy][ExtType] = (uint8_t)Action;
1095 /// setTruncStoreAction - Indicate that the specified truncating store does
1096 /// not work with the specified type and indicate what to do about it.
1097 void setTruncStoreAction(MVT ValVT, MVT MemVT,
1098 LegalizeAction Action) {
1099 assert(ValVT < MVT::LAST_VALUETYPE && MemVT < MVT::LAST_VALUETYPE &&
1100 "Table isn't big enough!");
1101 TruncStoreActions[ValVT.SimpleTy][MemVT.SimpleTy] = (uint8_t)Action;
1104 /// setIndexedLoadAction - Indicate that the specified indexed load does or
1105 /// does not work with the specified type and indicate what to do abort
1106 /// it. NOTE: All indexed mode loads are initialized to Expand in
1107 /// TargetLowering.cpp
1108 void setIndexedLoadAction(unsigned IdxMode, MVT VT,
1109 LegalizeAction Action) {
1110 assert(VT < MVT::LAST_VALUETYPE && IdxMode < ISD::LAST_INDEXED_MODE &&
1111 (unsigned)Action < 0xf && "Table isn't big enough!");
1112 // Load action are kept in the upper half.
1113 IndexedModeActions[(unsigned)VT.SimpleTy][IdxMode] &= ~0xf0;
1114 IndexedModeActions[(unsigned)VT.SimpleTy][IdxMode] |= ((uint8_t)Action) <<4;
1117 /// setIndexedStoreAction - Indicate that the specified indexed store does or
1118 /// does not work with the specified type and indicate what to do about
1119 /// it. NOTE: All indexed mode stores are initialized to Expand in
1120 /// TargetLowering.cpp
1121 void setIndexedStoreAction(unsigned IdxMode, MVT VT,
1122 LegalizeAction Action) {
1123 assert(VT < MVT::LAST_VALUETYPE && IdxMode < ISD::LAST_INDEXED_MODE &&
1124 (unsigned)Action < 0xf && "Table isn't big enough!");
1125 // Store action are kept in the lower half.
1126 IndexedModeActions[(unsigned)VT.SimpleTy][IdxMode] &= ~0x0f;
1127 IndexedModeActions[(unsigned)VT.SimpleTy][IdxMode] |= ((uint8_t)Action);
1130 /// setCondCodeAction - Indicate that the specified condition code is or isn't
1131 /// supported on the target and indicate what to do about it.
1132 void setCondCodeAction(ISD::CondCode CC, MVT VT,
1133 LegalizeAction Action) {
1134 assert(VT < MVT::LAST_VALUETYPE &&
1135 (unsigned)CC < array_lengthof(CondCodeActions) &&
1136 "Table isn't big enough!");
1137 CondCodeActions[(unsigned)CC] &= ~(uint64_t(3UL) << VT.SimpleTy*2);
1138 CondCodeActions[(unsigned)CC] |= (uint64_t)Action << VT.SimpleTy*2;
1141 /// AddPromotedToType - If Opc/OrigVT is specified as being promoted, the
1142 /// promotion code defaults to trying a larger integer/fp until it can find
1143 /// one that works. If that default is insufficient, this method can be used
1144 /// by the target to override the default.
1145 void AddPromotedToType(unsigned Opc, MVT OrigVT, MVT DestVT) {
1146 PromoteToType[std::make_pair(Opc, OrigVT.SimpleTy)] = DestVT.SimpleTy;
1149 /// setTargetDAGCombine - Targets should invoke this method for each target
1150 /// independent node that they want to provide a custom DAG combiner for by
1151 /// implementing the PerformDAGCombine virtual method.
1152 void setTargetDAGCombine(ISD::NodeType NT) {
1153 assert(unsigned(NT >> 3) < array_lengthof(TargetDAGCombineArray));
1154 TargetDAGCombineArray[NT >> 3] |= 1 << (NT&7);
1157 /// setJumpBufSize - Set the target's required jmp_buf buffer size (in
1158 /// bytes); default is 200
1159 void setJumpBufSize(unsigned Size) {
1163 /// setJumpBufAlignment - Set the target's required jmp_buf buffer
1164 /// alignment (in bytes); default is 0
1165 void setJumpBufAlignment(unsigned Align) {
1166 JumpBufAlignment = Align;
1169 /// setPrefLoopAlignment - Set the target's preferred loop alignment. Default
1170 /// alignment is zero, it means the target does not care about loop alignment.
1171 void setPrefLoopAlignment(unsigned Align) {
1172 PrefLoopAlignment = Align;
1175 /// setMinStackArgumentAlignment - Set the minimum stack alignment of an
1177 void setMinStackArgumentAlignment(unsigned Align) {
1178 MinStackArgumentAlignment = Align;
1181 /// setShouldFoldAtomicFences - Set if the target's implementation of the
1182 /// atomic operation intrinsics includes locking. Default is false.
1183 void setShouldFoldAtomicFences(bool fold) {
1184 ShouldFoldAtomicFences = fold;
1188 //===--------------------------------------------------------------------===//
1189 // Lowering methods - These methods must be implemented by targets so that
1190 // the SelectionDAGLowering code knows how to lower these.
1193 /// LowerFormalArguments - This hook must be implemented to lower the
1194 /// incoming (formal) arguments, described by the Ins array, into the
1195 /// specified DAG. The implementation should fill in the InVals array
1196 /// with legal-type argument values, and return the resulting token
1200 LowerFormalArguments(SDValue Chain,
1201 CallingConv::ID CallConv, bool isVarArg,
1202 const SmallVectorImpl<ISD::InputArg> &Ins,
1203 DebugLoc dl, SelectionDAG &DAG,
1204 SmallVectorImpl<SDValue> &InVals) const {
1205 assert(0 && "Not Implemented");
1206 return SDValue(); // this is here to silence compiler errors
1209 /// LowerCallTo - This function lowers an abstract call to a function into an
1210 /// actual call. This returns a pair of operands. The first element is the
1211 /// return value for the function (if RetTy is not VoidTy). The second
1212 /// element is the outgoing token chain. It calls LowerCall to do the actual
1214 struct ArgListEntry {
1225 ArgListEntry() : isSExt(false), isZExt(false), isInReg(false),
1226 isSRet(false), isNest(false), isByVal(false), Alignment(0) { }
1228 typedef std::vector<ArgListEntry> ArgListTy;
1229 std::pair<SDValue, SDValue>
1230 LowerCallTo(SDValue Chain, const Type *RetTy, bool RetSExt, bool RetZExt,
1231 bool isVarArg, bool isInreg, unsigned NumFixedArgs,
1232 CallingConv::ID CallConv, bool isTailCall,
1233 bool isReturnValueUsed, SDValue Callee, ArgListTy &Args,
1234 SelectionDAG &DAG, DebugLoc dl) const;
1236 /// LowerCall - This hook must be implemented to lower calls into the
1237 /// the specified DAG. The outgoing arguments to the call are described
1238 /// by the Outs array, and the values to be returned by the call are
1239 /// described by the Ins array. The implementation should fill in the
1240 /// InVals array with legal-type return values from the call, and return
1241 /// the resulting token chain value.
1243 LowerCall(SDValue Chain, SDValue Callee,
1244 CallingConv::ID CallConv, bool isVarArg, bool &isTailCall,
1245 const SmallVectorImpl<ISD::OutputArg> &Outs,
1246 const SmallVectorImpl<SDValue> &OutVals,
1247 const SmallVectorImpl<ISD::InputArg> &Ins,
1248 DebugLoc dl, SelectionDAG &DAG,
1249 SmallVectorImpl<SDValue> &InVals) const {
1250 assert(0 && "Not Implemented");
1251 return SDValue(); // this is here to silence compiler errors
1254 /// HandleByVal - Target-specific cleanup for formal ByVal parameters.
1255 virtual void HandleByVal(CCState *) const {}
1257 /// CanLowerReturn - This hook should be implemented to check whether the
1258 /// return values described by the Outs array can fit into the return
1259 /// registers. If false is returned, an sret-demotion is performed.
1261 virtual bool CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
1262 const SmallVectorImpl<ISD::OutputArg> &Outs,
1263 LLVMContext &Context) const
1265 // Return true by default to get preexisting behavior.
1269 /// LowerReturn - This hook must be implemented to lower outgoing
1270 /// return values, described by the Outs array, into the specified
1271 /// DAG. The implementation should return the resulting token chain
1275 LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
1276 const SmallVectorImpl<ISD::OutputArg> &Outs,
1277 const SmallVectorImpl<SDValue> &OutVals,
1278 DebugLoc dl, SelectionDAG &DAG) const {
1279 assert(0 && "Not Implemented");
1280 return SDValue(); // this is here to silence compiler errors
1283 /// isUsedByReturnOnly - Return true if result of the specified node is used
1284 /// by a return node only. This is used to determine whether it is possible
1285 /// to codegen a libcall as tail call at legalization time.
1286 virtual bool isUsedByReturnOnly(SDNode *N) const {
1290 /// mayBeEmittedAsTailCall - Return true if the target may be able emit the
1291 /// call instruction as a tail call. This is used by optimization passes to
1292 /// determine if it's profitable to duplicate return instructions to enable
1293 /// tailcall optimization.
1294 virtual bool mayBeEmittedAsTailCall(CallInst *CI) const {
1298 /// getTypeForExtArgOrReturn - Return the type that should be used to zero or
1299 /// sign extend a zeroext/signext integer argument or return value.
1300 /// FIXME: Most C calling convention requires the return type to be promoted,
1301 /// but this is not true all the time, e.g. i1 on x86-64. It is also not
1302 /// necessary for non-C calling conventions. The frontend should handle this
1303 /// and include all of the necessary information.
1304 virtual EVT getTypeForExtArgOrReturn(LLVMContext &Context, EVT VT,
1305 ISD::NodeType ExtendKind) const {
1306 EVT MinVT = getRegisterType(Context, MVT::i32);
1307 return VT.bitsLT(MinVT) ? MinVT : VT;
1310 /// LowerOperationWrapper - This callback is invoked by the type legalizer
1311 /// to legalize nodes with an illegal operand type but legal result types.
1312 /// It replaces the LowerOperation callback in the type Legalizer.
1313 /// The reason we can not do away with LowerOperation entirely is that
1314 /// LegalizeDAG isn't yet ready to use this callback.
1315 /// TODO: Consider merging with ReplaceNodeResults.
1317 /// The target places new result values for the node in Results (their number
1318 /// and types must exactly match those of the original return values of
1319 /// the node), or leaves Results empty, which indicates that the node is not
1320 /// to be custom lowered after all.
1321 /// The default implementation calls LowerOperation.
1322 virtual void LowerOperationWrapper(SDNode *N,
1323 SmallVectorImpl<SDValue> &Results,
1324 SelectionDAG &DAG) const;
1326 /// LowerOperation - This callback is invoked for operations that are
1327 /// unsupported by the target, which are registered to use 'custom' lowering,
1328 /// and whose defined values are all legal.
1329 /// If the target has no operations that require custom lowering, it need not
1330 /// implement this. The default implementation of this aborts.
1331 virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const;
1333 /// ReplaceNodeResults - This callback is invoked when a node result type is
1334 /// illegal for the target, and the operation was registered to use 'custom'
1335 /// lowering for that result type. The target places new result values for
1336 /// the node in Results (their number and types must exactly match those of
1337 /// the original return values of the node), or leaves Results empty, which
1338 /// indicates that the node is not to be custom lowered after all.
1340 /// If the target has no operations that require custom lowering, it need not
1341 /// implement this. The default implementation aborts.
1342 virtual void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results,
1343 SelectionDAG &DAG) const {
1344 assert(0 && "ReplaceNodeResults not implemented for this target!");
1347 /// getTargetNodeName() - This method returns the name of a target specific
1349 virtual const char *getTargetNodeName(unsigned Opcode) const;
1351 /// createFastISel - This method returns a target specific FastISel object,
1352 /// or null if the target does not support "fast" ISel.
1353 virtual FastISel *createFastISel(FunctionLoweringInfo &funcInfo) const {
1357 //===--------------------------------------------------------------------===//
1358 // Inline Asm Support hooks
1361 /// ExpandInlineAsm - This hook allows the target to expand an inline asm
1362 /// call to be explicit llvm code if it wants to. This is useful for
1363 /// turning simple inline asms into LLVM intrinsics, which gives the
1364 /// compiler more information about the behavior of the code.
1365 virtual bool ExpandInlineAsm(CallInst *CI) const {
1369 enum ConstraintType {
1370 C_Register, // Constraint represents specific register(s).
1371 C_RegisterClass, // Constraint represents any of register(s) in class.
1372 C_Memory, // Memory constraint.
1373 C_Other, // Something else.
1374 C_Unknown // Unsupported constraint.
1377 enum ConstraintWeight {
1379 CW_Invalid = -1, // No match.
1380 CW_Okay = 0, // Acceptable.
1381 CW_Good = 1, // Good weight.
1382 CW_Better = 2, // Better weight.
1383 CW_Best = 3, // Best weight.
1385 // Well-known weights.
1386 CW_SpecificReg = CW_Okay, // Specific register operands.
1387 CW_Register = CW_Good, // Register operands.
1388 CW_Memory = CW_Better, // Memory operands.
1389 CW_Constant = CW_Best, // Constant operand.
1390 CW_Default = CW_Okay // Default or don't know type.
1393 /// AsmOperandInfo - This contains information for each constraint that we are
1395 struct AsmOperandInfo : public InlineAsm::ConstraintInfo {
1396 /// ConstraintCode - This contains the actual string for the code, like "m".
1397 /// TargetLowering picks the 'best' code from ConstraintInfo::Codes that
1398 /// most closely matches the operand.
1399 std::string ConstraintCode;
1401 /// ConstraintType - Information about the constraint code, e.g. Register,
1402 /// RegisterClass, Memory, Other, Unknown.
1403 TargetLowering::ConstraintType ConstraintType;
1405 /// CallOperandval - If this is the result output operand or a
1406 /// clobber, this is null, otherwise it is the incoming operand to the
1407 /// CallInst. This gets modified as the asm is processed.
1408 Value *CallOperandVal;
1410 /// ConstraintVT - The ValueType for the operand value.
1413 /// isMatchingInputConstraint - Return true of this is an input operand that
1414 /// is a matching constraint like "4".
1415 bool isMatchingInputConstraint() const;
1417 /// getMatchedOperand - If this is an input matching constraint, this method
1418 /// returns the output operand it matches.
1419 unsigned getMatchedOperand() const;
1421 /// Copy constructor for copying from an AsmOperandInfo.
1422 AsmOperandInfo(const AsmOperandInfo &info)
1423 : InlineAsm::ConstraintInfo(info),
1424 ConstraintCode(info.ConstraintCode),
1425 ConstraintType(info.ConstraintType),
1426 CallOperandVal(info.CallOperandVal),
1427 ConstraintVT(info.ConstraintVT) {
1430 /// Copy constructor for copying from a ConstraintInfo.
1431 AsmOperandInfo(const InlineAsm::ConstraintInfo &info)
1432 : InlineAsm::ConstraintInfo(info),
1433 ConstraintType(TargetLowering::C_Unknown),
1434 CallOperandVal(0), ConstraintVT(MVT::Other) {
1438 typedef std::vector<AsmOperandInfo> AsmOperandInfoVector;
1440 /// ParseConstraints - Split up the constraint string from the inline
1441 /// assembly value into the specific constraints and their prefixes,
1442 /// and also tie in the associated operand values.
1443 /// If this returns an empty vector, and if the constraint string itself
1444 /// isn't empty, there was an error parsing.
1445 virtual AsmOperandInfoVector ParseConstraints(ImmutableCallSite CS) const;
1447 /// Examine constraint type and operand type and determine a weight value.
1448 /// The operand object must already have been set up with the operand type.
1449 virtual ConstraintWeight getMultipleConstraintMatchWeight(
1450 AsmOperandInfo &info, int maIndex) const;
1452 /// Examine constraint string and operand type and determine a weight value.
1453 /// The operand object must already have been set up with the operand type.
1454 virtual ConstraintWeight getSingleConstraintMatchWeight(
1455 AsmOperandInfo &info, const char *constraint) const;
1457 /// ComputeConstraintToUse - Determines the constraint code and constraint
1458 /// type to use for the specific AsmOperandInfo, setting
1459 /// OpInfo.ConstraintCode and OpInfo.ConstraintType. If the actual operand
1460 /// being passed in is available, it can be passed in as Op, otherwise an
1461 /// empty SDValue can be passed.
1462 virtual void ComputeConstraintToUse(AsmOperandInfo &OpInfo,
1464 SelectionDAG *DAG = 0) const;
1466 /// getConstraintType - Given a constraint, return the type of constraint it
1467 /// is for this target.
1468 virtual ConstraintType getConstraintType(const std::string &Constraint) const;
1470 /// getRegClassForInlineAsmConstraint - Given a constraint letter (e.g. "r"),
1471 /// return a list of registers that can be used to satisfy the constraint.
1472 /// This should only be used for C_RegisterClass constraints.
1473 virtual std::vector<unsigned>
1474 getRegClassForInlineAsmConstraint(const std::string &Constraint,
1477 /// getRegForInlineAsmConstraint - Given a physical register constraint (e.g.
1478 /// {edx}), return the register number and the register class for the
1481 /// Given a register class constraint, like 'r', if this corresponds directly
1482 /// to an LLVM register class, return a register of 0 and the register class
1485 /// This should only be used for C_Register constraints. On error,
1486 /// this returns a register number of 0 and a null register class pointer..
1487 virtual std::pair<unsigned, const TargetRegisterClass*>
1488 getRegForInlineAsmConstraint(const std::string &Constraint,
1491 /// LowerXConstraint - try to replace an X constraint, which matches anything,
1492 /// with another that has more specific requirements based on the type of the
1493 /// corresponding operand. This returns null if there is no replacement to
1495 virtual const char *LowerXConstraint(EVT ConstraintVT) const;
1497 /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
1498 /// vector. If it is invalid, don't add anything to Ops.
1499 virtual void LowerAsmOperandForConstraint(SDValue Op, char ConstraintLetter,
1500 std::vector<SDValue> &Ops,
1501 SelectionDAG &DAG) const;
1503 //===--------------------------------------------------------------------===//
1504 // Instruction Emitting Hooks
1507 // EmitInstrWithCustomInserter - This method should be implemented by targets
1508 // that mark instructions with the 'usesCustomInserter' flag. These
1509 // instructions are special in various ways, which require special support to
1510 // insert. The specified MachineInstr is created but not inserted into any
1511 // basic blocks, and this method is called to expand it into a sequence of
1512 // instructions, potentially also creating new basic blocks and control flow.
1513 virtual MachineBasicBlock *
1514 EmitInstrWithCustomInserter(MachineInstr *MI, MachineBasicBlock *MBB) const;
1516 //===--------------------------------------------------------------------===//
1517 // Addressing mode description hooks (used by LSR etc).
1520 /// AddrMode - This represents an addressing mode of:
1521 /// BaseGV + BaseOffs + BaseReg + Scale*ScaleReg
1522 /// If BaseGV is null, there is no BaseGV.
1523 /// If BaseOffs is zero, there is no base offset.
1524 /// If HasBaseReg is false, there is no base register.
1525 /// If Scale is zero, there is no ScaleReg. Scale of 1 indicates a reg with
1529 GlobalValue *BaseGV;
1533 AddrMode() : BaseGV(0), BaseOffs(0), HasBaseReg(false), Scale(0) {}
1536 /// isLegalAddressingMode - Return true if the addressing mode represented by
1537 /// AM is legal for this target, for a load/store of the specified type.
1538 /// The type may be VoidTy, in which case only return true if the addressing
1539 /// mode is legal for a load/store of any legal type.
1540 /// TODO: Handle pre/postinc as well.
1541 virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty) const;
1543 /// isTruncateFree - Return true if it's free to truncate a value of
1544 /// type Ty1 to type Ty2. e.g. On x86 it's free to truncate a i32 value in
1545 /// register EAX to i16 by referencing its sub-register AX.
1546 virtual bool isTruncateFree(const Type *Ty1, const Type *Ty2) const {
1550 virtual bool isTruncateFree(EVT VT1, EVT VT2) const {
1554 /// isZExtFree - Return true if any actual instruction that defines a
1555 /// value of type Ty1 implicitly zero-extends the value to Ty2 in the result
1556 /// register. This does not necessarily include registers defined in
1557 /// unknown ways, such as incoming arguments, or copies from unknown
1558 /// virtual registers. Also, if isTruncateFree(Ty2, Ty1) is true, this
1559 /// does not necessarily apply to truncate instructions. e.g. on x86-64,
1560 /// all instructions that define 32-bit values implicit zero-extend the
1561 /// result out to 64 bits.
1562 virtual bool isZExtFree(const Type *Ty1, const Type *Ty2) const {
1566 virtual bool isZExtFree(EVT VT1, EVT VT2) const {
1570 /// isNarrowingProfitable - Return true if it's profitable to narrow
1571 /// operations of type VT1 to VT2. e.g. on x86, it's profitable to narrow
1572 /// from i32 to i8 but not from i32 to i16.
1573 virtual bool isNarrowingProfitable(EVT VT1, EVT VT2) const {
1577 /// isLegalICmpImmediate - Return true if the specified immediate is legal
1578 /// icmp immediate, that is the target has icmp instructions which can compare
1579 /// a register against the immediate without having to materialize the
1580 /// immediate into a register.
1581 virtual bool isLegalICmpImmediate(int64_t Imm) const {
1585 //===--------------------------------------------------------------------===//
1586 // Div utility functions
1588 SDValue BuildSDIV(SDNode *N, SelectionDAG &DAG,
1589 std::vector<SDNode*>* Created) const;
1590 SDValue BuildUDIV(SDNode *N, SelectionDAG &DAG,
1591 std::vector<SDNode*>* Created) const;
1594 //===--------------------------------------------------------------------===//
1595 // Runtime Library hooks
1598 /// setLibcallName - Rename the default libcall routine name for the specified
1600 void setLibcallName(RTLIB::Libcall Call, const char *Name) {
1601 LibcallRoutineNames[Call] = Name;
1604 /// getLibcallName - Get the libcall routine name for the specified libcall.
1606 const char *getLibcallName(RTLIB::Libcall Call) const {
1607 return LibcallRoutineNames[Call];
1610 /// setCmpLibcallCC - Override the default CondCode to be used to test the
1611 /// result of the comparison libcall against zero.
1612 void setCmpLibcallCC(RTLIB::Libcall Call, ISD::CondCode CC) {
1613 CmpLibcallCCs[Call] = CC;
1616 /// getCmpLibcallCC - Get the CondCode that's to be used to test the result of
1617 /// the comparison libcall against zero.
1618 ISD::CondCode getCmpLibcallCC(RTLIB::Libcall Call) const {
1619 return CmpLibcallCCs[Call];
1622 /// setLibcallCallingConv - Set the CallingConv that should be used for the
1623 /// specified libcall.
1624 void setLibcallCallingConv(RTLIB::Libcall Call, CallingConv::ID CC) {
1625 LibcallCallingConvs[Call] = CC;
1628 /// getLibcallCallingConv - Get the CallingConv that should be used for the
1629 /// specified libcall.
1630 CallingConv::ID getLibcallCallingConv(RTLIB::Libcall Call) const {
1631 return LibcallCallingConvs[Call];
1635 const TargetMachine &TM;
1636 const TargetData *TD;
1637 const TargetLoweringObjectFile &TLOF;
1639 /// PointerTy - The type to use for pointers, usually i32 or i64.
1643 /// IsLittleEndian - True if this is a little endian target.
1645 bool IsLittleEndian;
1647 /// SelectIsExpensive - Tells the code generator not to expand operations
1648 /// into sequences that use the select operations if possible.
1649 bool SelectIsExpensive;
1651 /// IntDivIsCheap - Tells the code generator not to expand integer divides by
1652 /// constants into a sequence of muls, adds, and shifts. This is a hack until
1653 /// a real cost model is in place. If we ever optimize for size, this will be
1654 /// set to true unconditionally.
1657 /// Pow2DivIsCheap - Tells the code generator that it shouldn't generate
1658 /// srl/add/sra for a signed divide by power of two, and let the target handle
1660 bool Pow2DivIsCheap;
1662 /// JumpIsExpensive - Tells the code generator that it shouldn't generate
1663 /// extra flow control instructions and should attempt to combine flow
1664 /// control instructions via predication.
1665 bool JumpIsExpensive;
1667 /// UseUnderscoreSetJmp - This target prefers to use _setjmp to implement
1668 /// llvm.setjmp. Defaults to false.
1669 bool UseUnderscoreSetJmp;
1671 /// UseUnderscoreLongJmp - This target prefers to use _longjmp to implement
1672 /// llvm.longjmp. Defaults to false.
1673 bool UseUnderscoreLongJmp;
1675 /// BooleanContents - Information about the contents of the high-bits in
1676 /// boolean values held in a type wider than i1. See getBooleanContents.
1677 BooleanContent BooleanContents;
1679 /// SchedPreferenceInfo - The target scheduling preference: shortest possible
1680 /// total cycles or lowest register usage.
1681 Sched::Preference SchedPreferenceInfo;
1683 /// JumpBufSize - The size, in bytes, of the target's jmp_buf buffers
1684 unsigned JumpBufSize;
1686 /// JumpBufAlignment - The alignment, in bytes, of the target's jmp_buf
1688 unsigned JumpBufAlignment;
1690 /// MinStackArgumentAlignment - The minimum alignment that any argument
1691 /// on the stack needs to have.
1693 unsigned MinStackArgumentAlignment;
1695 /// PrefLoopAlignment - The perferred loop alignment.
1697 unsigned PrefLoopAlignment;
1699 /// ShouldFoldAtomicFences - Whether fencing MEMBARRIER instructions should
1700 /// be folded into the enclosed atomic intrinsic instruction by the
1702 bool ShouldFoldAtomicFences;
1704 /// StackPointerRegisterToSaveRestore - If set to a physical register, this
1705 /// specifies the register that llvm.savestack/llvm.restorestack should save
1707 unsigned StackPointerRegisterToSaveRestore;
1709 /// ExceptionPointerRegister - If set to a physical register, this specifies
1710 /// the register that receives the exception address on entry to a landing
1712 unsigned ExceptionPointerRegister;
1714 /// ExceptionSelectorRegister - If set to a physical register, this specifies
1715 /// the register that receives the exception typeid on entry to a landing
1717 unsigned ExceptionSelectorRegister;
1719 /// RegClassForVT - This indicates the default register class to use for
1720 /// each ValueType the target supports natively.
1721 TargetRegisterClass *RegClassForVT[MVT::LAST_VALUETYPE];
1722 unsigned char NumRegistersForVT[MVT::LAST_VALUETYPE];
1723 EVT RegisterTypeForVT[MVT::LAST_VALUETYPE];
1725 /// RepRegClassForVT - This indicates the "representative" register class to
1726 /// use for each ValueType the target supports natively. This information is
1727 /// used by the scheduler to track register pressure. By default, the
1728 /// representative register class is the largest legal super-reg register
1729 /// class of the register class of the specified type. e.g. On x86, i8, i16,
1730 /// and i32's representative class would be GR32.
1731 const TargetRegisterClass *RepRegClassForVT[MVT::LAST_VALUETYPE];
1733 /// RepRegClassCostForVT - This indicates the "cost" of the "representative"
1734 /// register class for each ValueType. The cost is used by the scheduler to
1735 /// approximate register pressure.
1736 uint8_t RepRegClassCostForVT[MVT::LAST_VALUETYPE];
1738 /// TransformToType - For any value types we are promoting or expanding, this
1739 /// contains the value type that we are changing to. For Expanded types, this
1740 /// contains one step of the expand (e.g. i64 -> i32), even if there are
1741 /// multiple steps required (e.g. i64 -> i16). For types natively supported
1742 /// by the system, this holds the same type (e.g. i32 -> i32).
1743 EVT TransformToType[MVT::LAST_VALUETYPE];
1745 /// OpActions - For each operation and each value type, keep a LegalizeAction
1746 /// that indicates how instruction selection should deal with the operation.
1747 /// Most operations are Legal (aka, supported natively by the target), but
1748 /// operations that are not should be described. Note that operations on
1749 /// non-legal value types are not described here.
1750 uint8_t OpActions[MVT::LAST_VALUETYPE][ISD::BUILTIN_OP_END];
1752 /// LoadExtActions - For each load extension type and each value type,
1753 /// keep a LegalizeAction that indicates how instruction selection should deal
1754 /// with a load of a specific value type and extension type.
1755 uint8_t LoadExtActions[MVT::LAST_VALUETYPE][ISD::LAST_LOADEXT_TYPE];
1757 /// TruncStoreActions - For each value type pair keep a LegalizeAction that
1758 /// indicates whether a truncating store of a specific value type and
1759 /// truncating type is legal.
1760 uint8_t TruncStoreActions[MVT::LAST_VALUETYPE][MVT::LAST_VALUETYPE];
1762 /// IndexedModeActions - For each indexed mode and each value type,
1763 /// keep a pair of LegalizeAction that indicates how instruction
1764 /// selection should deal with the load / store. The first dimension is the
1765 /// value_type for the reference. The second dimension represents the various
1766 /// modes for load store.
1767 uint8_t IndexedModeActions[MVT::LAST_VALUETYPE][ISD::LAST_INDEXED_MODE];
1769 /// CondCodeActions - For each condition code (ISD::CondCode) keep a
1770 /// LegalizeAction that indicates how instruction selection should
1771 /// deal with the condition code.
1772 uint64_t CondCodeActions[ISD::SETCC_INVALID];
1774 ValueTypeActionImpl ValueTypeActions;
1776 std::vector<std::pair<EVT, TargetRegisterClass*> > AvailableRegClasses;
1778 /// TargetDAGCombineArray - Targets can specify ISD nodes that they would
1779 /// like PerformDAGCombine callbacks for by calling setTargetDAGCombine(),
1780 /// which sets a bit in this array.
1782 TargetDAGCombineArray[(ISD::BUILTIN_OP_END+CHAR_BIT-1)/CHAR_BIT];
1784 /// PromoteToType - For operations that must be promoted to a specific type,
1785 /// this holds the destination type. This map should be sparse, so don't hold
1788 /// Targets add entries to this map with AddPromotedToType(..), clients access
1789 /// this with getTypeToPromoteTo(..).
1790 std::map<std::pair<unsigned, MVT::SimpleValueType>, MVT::SimpleValueType>
1793 /// LibcallRoutineNames - Stores the name each libcall.
1795 const char *LibcallRoutineNames[RTLIB::UNKNOWN_LIBCALL];
1797 /// CmpLibcallCCs - The ISD::CondCode that should be used to test the result
1798 /// of each of the comparison libcall against zero.
1799 ISD::CondCode CmpLibcallCCs[RTLIB::UNKNOWN_LIBCALL];
1801 /// LibcallCallingConvs - Stores the CallingConv that should be used for each
1803 CallingConv::ID LibcallCallingConvs[RTLIB::UNKNOWN_LIBCALL];
1806 /// When lowering \@llvm.memset this field specifies the maximum number of
1807 /// store operations that may be substituted for the call to memset. Targets
1808 /// must set this value based on the cost threshold for that target. Targets
1809 /// should assume that the memset will be done using as many of the largest
1810 /// store operations first, followed by smaller ones, if necessary, per
1811 /// alignment restrictions. For example, storing 9 bytes on a 32-bit machine
1812 /// with 16-bit alignment would result in four 2-byte stores and one 1-byte
1813 /// store. This only applies to setting a constant array of a constant size.
1814 /// @brief Specify maximum number of store instructions per memset call.
1815 unsigned maxStoresPerMemset;
1817 /// Maximum number of stores operations that may be substituted for the call
1818 /// to memset, used for functions with OptSize attribute.
1819 unsigned maxStoresPerMemsetOptSize;
1821 /// When lowering \@llvm.memcpy this field specifies the maximum number of
1822 /// store operations that may be substituted for a call to memcpy. Targets
1823 /// must set this value based on the cost threshold for that target. Targets
1824 /// should assume that the memcpy will be done using as many of the largest
1825 /// store operations first, followed by smaller ones, if necessary, per
1826 /// alignment restrictions. For example, storing 7 bytes on a 32-bit machine
1827 /// with 32-bit alignment would result in one 4-byte store, a one 2-byte store
1828 /// and one 1-byte store. This only applies to copying a constant array of
1830 /// @brief Specify maximum bytes of store instructions per memcpy call.
1831 unsigned maxStoresPerMemcpy;
1833 /// Maximum number of store operations that may be substituted for a call
1834 /// to memcpy, used for functions with OptSize attribute.
1835 unsigned maxStoresPerMemcpyOptSize;
1837 /// When lowering \@llvm.memmove this field specifies the maximum number of
1838 /// store instructions that may be substituted for a call to memmove. Targets
1839 /// must set this value based on the cost threshold for that target. Targets
1840 /// should assume that the memmove will be done using as many of the largest
1841 /// store operations first, followed by smaller ones, if necessary, per
1842 /// alignment restrictions. For example, moving 9 bytes on a 32-bit machine
1843 /// with 8-bit alignment would result in nine 1-byte stores. This only
1844 /// applies to copying a constant array of constant size.
1845 /// @brief Specify maximum bytes of store instructions per memmove call.
1846 unsigned maxStoresPerMemmove;
1848 /// Maximum number of store instructions that may be substituted for a call
1849 /// to memmove, used for functions with OpSize attribute.
1850 unsigned maxStoresPerMemmoveOptSize;
1852 /// This field specifies whether the target can benefit from code placement
1854 bool benefitFromCodePlacementOpt;
1857 /// isLegalRC - Return true if the value types that can be represented by the
1858 /// specified register class are all legal.
1859 bool isLegalRC(const TargetRegisterClass *RC) const;
1861 /// hasLegalSuperRegRegClasses - Return true if the specified register class
1862 /// has one or more super-reg register classes that are legal.
1863 bool hasLegalSuperRegRegClasses(const TargetRegisterClass *RC) const;
1866 /// GetReturnInfo - Given an LLVM IR type and return type attributes,
1867 /// compute the return value EVTs and flags, and optionally also
1868 /// the offsets, if the return value is being lowered to memory.
1869 void GetReturnInfo(const Type* ReturnType, Attributes attr,
1870 SmallVectorImpl<ISD::OutputArg> &Outs,
1871 const TargetLowering &TLI,
1872 SmallVectorImpl<uint64_t> *Offsets = 0);
1874 } // end llvm namespace