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/Constants.h"
26 #include "llvm/InlineAsm.h"
27 #include "llvm/CodeGen/SelectionDAGNodes.h"
28 #include "llvm/CodeGen/RuntimeLibcalls.h"
29 #include "llvm/ADT/APFloat.h"
30 #include "llvm/ADT/STLExtras.h"
36 class MachineBasicBlock;
37 class MachineFrameInfo;
44 class TargetRegisterClass;
45 class TargetSubtarget;
49 //===----------------------------------------------------------------------===//
50 /// TargetLowering - This class defines information used to lower LLVM code to
51 /// legal SelectionDAG operators that the target instruction selector can accept
54 /// This class also defines callbacks that targets must implement to lower
55 /// target-specific constructs to SelectionDAG operators.
57 class TargetLowering {
59 /// LegalizeAction - This enum indicates whether operations are valid for a
60 /// target, and if not, what action should be used to make them valid.
62 Legal, // The target natively supports this operation.
63 Promote, // This operation should be executed in a larger type.
64 Expand, // Try to expand this to other ops, otherwise use a libcall.
65 Custom // Use the LowerOperation hook to implement custom lowering.
68 enum OutOfRangeShiftAmount {
69 Undefined, // Oversized shift amounts are undefined (default).
70 Mask, // Shift amounts are auto masked (anded) to value size.
71 Extend // Oversized shift pulls in zeros or sign bits.
74 enum SetCCResultValue {
75 UndefinedSetCCResult, // SetCC returns a garbage/unknown extend.
76 ZeroOrOneSetCCResult, // SetCC returns a zero extended result.
77 ZeroOrNegativeOneSetCCResult // SetCC returns a sign extended result.
80 enum SchedPreference {
81 SchedulingForLatency, // Scheduling for shortest total latency.
82 SchedulingForRegPressure // Scheduling for lowest register pressure.
85 explicit TargetLowering(TargetMachine &TM);
86 virtual ~TargetLowering();
88 TargetMachine &getTargetMachine() const { return TM; }
89 const TargetData *getTargetData() const { return TD; }
91 bool isBigEndian() const { return !IsLittleEndian; }
92 bool isLittleEndian() const { return IsLittleEndian; }
93 MVT::ValueType getPointerTy() const { return PointerTy; }
94 MVT::ValueType getShiftAmountTy() const { return ShiftAmountTy; }
95 OutOfRangeShiftAmount getShiftAmountFlavor() const {return ShiftAmtHandling; }
97 /// usesGlobalOffsetTable - Return true if this target uses a GOT for PIC
99 bool usesGlobalOffsetTable() const { return UsesGlobalOffsetTable; }
101 /// isSelectExpensive - Return true if the select operation is expensive for
103 bool isSelectExpensive() const { return SelectIsExpensive; }
105 /// isIntDivCheap() - Return true if integer divide is usually cheaper than
106 /// a sequence of several shifts, adds, and multiplies for this target.
107 bool isIntDivCheap() const { return IntDivIsCheap; }
109 /// isPow2DivCheap() - Return true if pow2 div is cheaper than a chain of
111 bool isPow2DivCheap() const { return Pow2DivIsCheap; }
113 /// getSetCCResultType - Return the ValueType of the result of setcc
115 virtual MVT::ValueType getSetCCResultType(const SDOperand &) const;
117 /// getSetCCResultContents - For targets without boolean registers, this flag
118 /// returns information about the contents of the high-bits in the setcc
120 SetCCResultValue getSetCCResultContents() const { return SetCCResultContents;}
122 /// getSchedulingPreference - Return target scheduling preference.
123 SchedPreference getSchedulingPreference() const {
124 return SchedPreferenceInfo;
127 /// getRegClassFor - Return the register class that should be used for the
128 /// specified value type. This may only be called on legal types.
129 TargetRegisterClass *getRegClassFor(MVT::ValueType VT) const {
130 assert(VT < array_lengthof(RegClassForVT));
131 TargetRegisterClass *RC = RegClassForVT[VT];
132 assert(RC && "This value type is not natively supported!");
136 /// isTypeLegal - Return true if the target has native support for the
137 /// specified value type. This means that it has a register that directly
138 /// holds it without promotions or expansions.
139 bool isTypeLegal(MVT::ValueType VT) const {
140 assert(MVT::isExtendedVT(VT) || VT < array_lengthof(RegClassForVT));
141 return !MVT::isExtendedVT(VT) && RegClassForVT[VT] != 0;
144 class ValueTypeActionImpl {
145 /// ValueTypeActions - This is a bitvector that contains two bits for each
146 /// value type, where the two bits correspond to the LegalizeAction enum.
147 /// This can be queried with "getTypeAction(VT)".
148 uint32_t ValueTypeActions[2];
150 ValueTypeActionImpl() {
151 ValueTypeActions[0] = ValueTypeActions[1] = 0;
153 ValueTypeActionImpl(const ValueTypeActionImpl &RHS) {
154 ValueTypeActions[0] = RHS.ValueTypeActions[0];
155 ValueTypeActions[1] = RHS.ValueTypeActions[1];
158 LegalizeAction getTypeAction(MVT::ValueType VT) const {
159 if (MVT::isExtendedVT(VT)) {
160 if (MVT::isVector(VT)) return Expand;
161 if (MVT::isInteger(VT))
162 // First promote to a power-of-two size, then expand if necessary.
163 return VT == MVT::RoundIntegerType(VT) ? Expand : Promote;
164 assert(0 && "Unsupported extended type!");
166 assert(VT<4*array_lengthof(ValueTypeActions)*sizeof(ValueTypeActions[0]));
167 return (LegalizeAction)((ValueTypeActions[VT>>4] >> ((2*VT) & 31)) & 3);
169 void setTypeAction(MVT::ValueType VT, LegalizeAction Action) {
170 assert(VT<4*array_lengthof(ValueTypeActions)*sizeof(ValueTypeActions[0]));
171 ValueTypeActions[VT>>4] |= Action << ((VT*2) & 31);
175 const ValueTypeActionImpl &getValueTypeActions() const {
176 return ValueTypeActions;
179 /// getTypeAction - Return how we should legalize values of this type, either
180 /// it is already legal (return 'Legal') or we need to promote it to a larger
181 /// type (return 'Promote'), or we need to expand it into multiple registers
182 /// of smaller integer type (return 'Expand'). 'Custom' is not an option.
183 LegalizeAction getTypeAction(MVT::ValueType VT) const {
184 return ValueTypeActions.getTypeAction(VT);
187 /// getTypeToTransformTo - For types supported by the target, this is an
188 /// identity function. For types that must be promoted to larger types, this
189 /// returns the larger type to promote to. For integer types that are larger
190 /// than the largest integer register, this contains one step in the expansion
191 /// to get to the smaller register. For illegal floating point types, this
192 /// returns the integer type to transform to.
193 MVT::ValueType getTypeToTransformTo(MVT::ValueType VT) const {
194 if (!MVT::isExtendedVT(VT)) {
195 assert(VT < array_lengthof(TransformToType));
196 MVT::ValueType NVT = TransformToType[VT];
197 assert(getTypeAction(NVT) != Promote &&
198 "Promote may not follow Expand or Promote");
202 if (MVT::isVector(VT))
203 return MVT::getVectorType(MVT::getVectorElementType(VT),
204 MVT::getVectorNumElements(VT) / 2);
205 if (MVT::isInteger(VT)) {
206 MVT::ValueType NVT = MVT::RoundIntegerType(VT);
208 // Size is a power of two - expand to half the size.
209 return MVT::getIntegerType(MVT::getSizeInBits(VT) / 2);
211 // Promote to a power of two size, avoiding multi-step promotion.
212 return getTypeAction(NVT) == Promote ? getTypeToTransformTo(NVT) : NVT;
214 assert(0 && "Unsupported extended type!");
215 return MVT::ValueType(); // Not reached
218 /// getTypeToExpandTo - For types supported by the target, this is an
219 /// identity function. For types that must be expanded (i.e. integer types
220 /// that are larger than the largest integer register or illegal floating
221 /// point types), this returns the largest legal type it will be expanded to.
222 MVT::ValueType getTypeToExpandTo(MVT::ValueType VT) const {
223 assert(!MVT::isVector(VT));
225 switch (getTypeAction(VT)) {
229 VT = getTypeToTransformTo(VT);
232 assert(false && "Type is not legal nor is it to be expanded!");
239 /// getVectorTypeBreakdown - Vector types are broken down into some number of
240 /// legal first class types. For example, MVT::v8f32 maps to 2 MVT::v4f32
241 /// with Altivec or SSE1, or 8 promoted MVT::f64 values with the X86 FP stack.
242 /// Similarly, MVT::v2i64 turns into 4 MVT::i32 values with both PPC and X86.
244 /// This method returns the number of registers needed, and the VT for each
245 /// register. It also returns the VT and quantity of the intermediate values
246 /// before they are promoted/expanded.
248 unsigned getVectorTypeBreakdown(MVT::ValueType VT,
249 MVT::ValueType &IntermediateVT,
250 unsigned &NumIntermediates,
251 MVT::ValueType &RegisterVT) const;
253 typedef std::vector<APFloat>::const_iterator legal_fpimm_iterator;
254 legal_fpimm_iterator legal_fpimm_begin() const {
255 return LegalFPImmediates.begin();
257 legal_fpimm_iterator legal_fpimm_end() const {
258 return LegalFPImmediates.end();
261 /// isShuffleMaskLegal - Targets can use this to indicate that they only
262 /// support *some* VECTOR_SHUFFLE operations, those with specific masks.
263 /// By default, if a target supports the VECTOR_SHUFFLE node, all mask values
264 /// are assumed to be legal.
265 virtual bool isShuffleMaskLegal(SDOperand Mask, MVT::ValueType VT) const {
269 /// isVectorClearMaskLegal - Similar to isShuffleMaskLegal. This is
270 /// used by Targets can use this to indicate if there is a suitable
271 /// VECTOR_SHUFFLE that can be used to replace a VAND with a constant
273 virtual bool isVectorClearMaskLegal(const std::vector<SDOperand> &BVOps,
275 SelectionDAG &DAG) const {
279 /// getOperationAction - Return how this operation should be treated: either
280 /// it is legal, needs to be promoted to a larger size, needs to be
281 /// expanded to some other code sequence, or the target has a custom expander
283 LegalizeAction getOperationAction(unsigned Op, MVT::ValueType VT) const {
284 if (MVT::isExtendedVT(VT)) return Expand;
285 assert(Op < array_lengthof(OpActions) &&
286 VT < sizeof(OpActions[0])*4 && "Table isn't big enough!");
287 return (LegalizeAction)((OpActions[Op] >> (2*VT)) & 3);
290 /// isOperationLegal - Return true if the specified operation is legal on this
292 bool isOperationLegal(unsigned Op, MVT::ValueType VT) const {
293 return getOperationAction(Op, VT) == Legal ||
294 getOperationAction(Op, VT) == Custom;
297 /// getLoadXAction - Return how this load with extension should be treated:
298 /// either it is legal, needs to be promoted to a larger size, needs to be
299 /// expanded to some other code sequence, or the target has a custom expander
301 LegalizeAction getLoadXAction(unsigned LType, MVT::ValueType VT) const {
302 assert(LType < array_lengthof(LoadXActions) &&
303 VT < sizeof(LoadXActions[0])*4 && "Table isn't big enough!");
304 return (LegalizeAction)((LoadXActions[LType] >> (2*VT)) & 3);
307 /// isLoadXLegal - Return true if the specified load with extension is legal
309 bool isLoadXLegal(unsigned LType, MVT::ValueType VT) const {
310 return !MVT::isExtendedVT(VT) &&
311 (getLoadXAction(LType, VT) == Legal ||
312 getLoadXAction(LType, VT) == Custom);
315 /// getTruncStoreAction - Return how this store with truncation should be
316 /// treated: either it is legal, needs to be promoted to a larger size, needs
317 /// to be expanded to some other code sequence, or the target has a custom
319 LegalizeAction getTruncStoreAction(MVT::ValueType ValVT,
320 MVT::ValueType MemVT) const {
321 assert(ValVT < array_lengthof(TruncStoreActions) &&
322 MemVT < sizeof(TruncStoreActions[0])*4 && "Table isn't big enough!");
323 return (LegalizeAction)((TruncStoreActions[ValVT] >> (2*MemVT)) & 3);
326 /// isTruncStoreLegal - Return true if the specified store with truncation is
327 /// legal on this target.
328 bool isTruncStoreLegal(MVT::ValueType ValVT, MVT::ValueType MemVT) const {
329 return !MVT::isExtendedVT(MemVT) &&
330 (getTruncStoreAction(ValVT, MemVT) == Legal ||
331 getTruncStoreAction(ValVT, MemVT) == Custom);
334 /// getIndexedLoadAction - Return how the indexed load should be treated:
335 /// either it is legal, needs to be promoted to a larger size, needs to be
336 /// expanded to some other code sequence, or the target has a custom expander
339 getIndexedLoadAction(unsigned IdxMode, MVT::ValueType VT) const {
340 assert(IdxMode < array_lengthof(IndexedModeActions[0]) &&
341 VT < sizeof(IndexedModeActions[0][0])*4 &&
342 "Table isn't big enough!");
343 return (LegalizeAction)((IndexedModeActions[0][IdxMode] >> (2*VT)) & 3);
346 /// isIndexedLoadLegal - Return true if the specified indexed load is legal
348 bool isIndexedLoadLegal(unsigned IdxMode, MVT::ValueType VT) const {
349 return getIndexedLoadAction(IdxMode, VT) == Legal ||
350 getIndexedLoadAction(IdxMode, VT) == Custom;
353 /// getIndexedStoreAction - Return how the indexed store should be treated:
354 /// either it is legal, needs to be promoted to a larger size, needs to be
355 /// expanded to some other code sequence, or the target has a custom expander
358 getIndexedStoreAction(unsigned IdxMode, MVT::ValueType VT) const {
359 assert(IdxMode < array_lengthof(IndexedModeActions[1]) &&
360 VT < sizeof(IndexedModeActions[1][0])*4 &&
361 "Table isn't big enough!");
362 return (LegalizeAction)((IndexedModeActions[1][IdxMode] >> (2*VT)) & 3);
365 /// isIndexedStoreLegal - Return true if the specified indexed load is legal
367 bool isIndexedStoreLegal(unsigned IdxMode, MVT::ValueType VT) const {
368 return getIndexedStoreAction(IdxMode, VT) == Legal ||
369 getIndexedStoreAction(IdxMode, VT) == Custom;
372 /// getConvertAction - Return how the conversion should be treated:
373 /// either it is legal, needs to be promoted to a larger size, needs to be
374 /// expanded to some other code sequence, or the target has a custom expander
377 getConvertAction(MVT::ValueType FromVT, MVT::ValueType ToVT) const {
378 assert(FromVT < array_lengthof(ConvertActions) &&
379 ToVT < sizeof(ConvertActions[0])*4 && "Table isn't big enough!");
380 return (LegalizeAction)((ConvertActions[FromVT] >> (2*ToVT)) & 3);
383 /// isConvertLegal - Return true if the specified conversion is legal
385 bool isConvertLegal(MVT::ValueType FromVT, MVT::ValueType ToVT) const {
386 return getConvertAction(FromVT, ToVT) == Legal ||
387 getConvertAction(FromVT, ToVT) == Custom;
390 /// getTypeToPromoteTo - If the action for this operation is to promote, this
391 /// method returns the ValueType to promote to.
392 MVT::ValueType getTypeToPromoteTo(unsigned Op, MVT::ValueType VT) const {
393 assert(getOperationAction(Op, VT) == Promote &&
394 "This operation isn't promoted!");
396 // See if this has an explicit type specified.
397 std::map<std::pair<unsigned, MVT::ValueType>,
398 MVT::ValueType>::const_iterator PTTI =
399 PromoteToType.find(std::make_pair(Op, VT));
400 if (PTTI != PromoteToType.end()) return PTTI->second;
402 assert((MVT::isInteger(VT) || MVT::isFloatingPoint(VT)) &&
403 "Cannot autopromote this type, add it with AddPromotedToType.");
405 MVT::ValueType NVT = VT;
407 NVT = (MVT::ValueType)(NVT+1);
408 assert(MVT::isInteger(NVT) == MVT::isInteger(VT) && NVT != MVT::isVoid &&
409 "Didn't find type to promote to!");
410 } while (!isTypeLegal(NVT) ||
411 getOperationAction(Op, NVT) == Promote);
415 /// getValueType - Return the MVT::ValueType corresponding to this LLVM type.
416 /// This is fixed by the LLVM operations except for the pointer size. If
417 /// AllowUnknown is true, this will return MVT::Other for types with no MVT
418 /// counterpart (e.g. structs), otherwise it will assert.
419 MVT::ValueType getValueType(const Type *Ty, bool AllowUnknown = false) const {
420 MVT::ValueType VT = MVT::getValueType(Ty, AllowUnknown);
421 return VT == MVT::iPTR ? PointerTy : VT;
424 /// getByValTypeAlignment - Return the desired alignment for ByVal aggregate
425 /// function arguments in the caller parameter area. This is the actual
426 /// alignment, not its logarithm.
427 virtual unsigned getByValTypeAlignment(const Type *Ty) const;
429 /// getRegisterType - Return the type of registers that this ValueType will
430 /// eventually require.
431 MVT::ValueType getRegisterType(MVT::ValueType VT) const {
432 if (!MVT::isExtendedVT(VT)) {
433 assert(VT < array_lengthof(RegisterTypeForVT));
434 return RegisterTypeForVT[VT];
436 if (MVT::isVector(VT)) {
437 MVT::ValueType VT1, RegisterVT;
438 unsigned NumIntermediates;
439 (void)getVectorTypeBreakdown(VT, VT1, NumIntermediates, RegisterVT);
442 if (MVT::isInteger(VT)) {
443 return getRegisterType(getTypeToTransformTo(VT));
445 assert(0 && "Unsupported extended type!");
446 return MVT::ValueType(); // Not reached
449 /// getNumRegisters - Return the number of registers that this ValueType will
450 /// eventually require. This is one for any types promoted to live in larger
451 /// registers, but may be more than one for types (like i64) that are split
452 /// into pieces. For types like i140, which are first promoted then expanded,
453 /// it is the number of registers needed to hold all the bits of the original
454 /// type. For an i140 on a 32 bit machine this means 5 registers.
455 unsigned getNumRegisters(MVT::ValueType VT) const {
456 if (!MVT::isExtendedVT(VT)) {
457 assert(VT < array_lengthof(NumRegistersForVT));
458 return NumRegistersForVT[VT];
460 if (MVT::isVector(VT)) {
461 MVT::ValueType VT1, VT2;
462 unsigned NumIntermediates;
463 return getVectorTypeBreakdown(VT, VT1, NumIntermediates, VT2);
465 if (MVT::isInteger(VT)) {
466 unsigned BitWidth = MVT::getSizeInBits(VT);
467 unsigned RegWidth = MVT::getSizeInBits(getRegisterType(VT));
468 return (BitWidth + RegWidth - 1) / RegWidth;
470 assert(0 && "Unsupported extended type!");
471 return 0; // Not reached
474 /// ShouldShrinkFPConstant - If true, then instruction selection should
475 /// seek to shrink the FP constant of the specified type to a smaller type
476 /// in order to save space and / or reduce runtime.
477 virtual bool ShouldShrinkFPConstant(MVT::ValueType VT) const { return true; }
479 /// hasTargetDAGCombine - If true, the target has custom DAG combine
480 /// transformations that it can perform for the specified node.
481 bool hasTargetDAGCombine(ISD::NodeType NT) const {
482 assert(unsigned(NT >> 3) < array_lengthof(TargetDAGCombineArray));
483 return TargetDAGCombineArray[NT >> 3] & (1 << (NT&7));
486 /// This function returns the maximum number of store operations permitted
487 /// to replace a call to llvm.memset. The value is set by the target at the
488 /// performance threshold for such a replacement.
489 /// @brief Get maximum # of store operations permitted for llvm.memset
490 unsigned getMaxStoresPerMemset() const { return maxStoresPerMemset; }
492 /// This function returns the maximum number of store operations permitted
493 /// to replace a call to llvm.memcpy. The value is set by the target at the
494 /// performance threshold for such a replacement.
495 /// @brief Get maximum # of store operations permitted for llvm.memcpy
496 unsigned getMaxStoresPerMemcpy() const { return maxStoresPerMemcpy; }
498 /// This function returns the maximum number of store operations permitted
499 /// to replace a call to llvm.memmove. The value is set by the target at the
500 /// performance threshold for such a replacement.
501 /// @brief Get maximum # of store operations permitted for llvm.memmove
502 unsigned getMaxStoresPerMemmove() const { return maxStoresPerMemmove; }
504 /// This function returns true if the target allows unaligned memory accesses.
505 /// This is used, for example, in situations where an array copy/move/set is
506 /// converted to a sequence of store operations. It's use helps to ensure that
507 /// such replacements don't generate code that causes an alignment error
508 /// (trap) on the target machine.
509 /// @brief Determine if the target supports unaligned memory accesses.
510 bool allowsUnalignedMemoryAccesses() const {
511 return allowUnalignedMemoryAccesses;
514 /// getOptimalMemOpType - Returns the target specific optimal type for load
515 /// and store operations as a result of memset, memcpy, and memmove lowering.
516 /// It returns MVT::iAny if SelectionDAG should be responsible for
518 virtual MVT::ValueType getOptimalMemOpType(uint64_t Size, unsigned Align,
519 bool isSrcConst, bool isSrcStr) const {
523 /// usesUnderscoreSetJmp - Determine if we should use _setjmp or setjmp
524 /// to implement llvm.setjmp.
525 bool usesUnderscoreSetJmp() const {
526 return UseUnderscoreSetJmp;
529 /// usesUnderscoreLongJmp - Determine if we should use _longjmp or longjmp
530 /// to implement llvm.longjmp.
531 bool usesUnderscoreLongJmp() const {
532 return UseUnderscoreLongJmp;
535 /// getStackPointerRegisterToSaveRestore - If a physical register, this
536 /// specifies the register that llvm.savestack/llvm.restorestack should save
538 unsigned getStackPointerRegisterToSaveRestore() const {
539 return StackPointerRegisterToSaveRestore;
542 /// getExceptionAddressRegister - If a physical register, this returns
543 /// the register that receives the exception address on entry to a landing
545 unsigned getExceptionAddressRegister() const {
546 return ExceptionPointerRegister;
549 /// getExceptionSelectorRegister - If a physical register, this returns
550 /// the register that receives the exception typeid on entry to a landing
552 unsigned getExceptionSelectorRegister() const {
553 return ExceptionSelectorRegister;
556 /// getJumpBufSize - returns the target's jmp_buf size in bytes (if never
557 /// set, the default is 200)
558 unsigned getJumpBufSize() const {
562 /// getJumpBufAlignment - returns the target's jmp_buf alignment in bytes
563 /// (if never set, the default is 0)
564 unsigned getJumpBufAlignment() const {
565 return JumpBufAlignment;
568 /// getIfCvtBlockLimit - returns the target specific if-conversion block size
569 /// limit. Any block whose size is greater should not be predicated.
570 unsigned getIfCvtBlockSizeLimit() const {
571 return IfCvtBlockSizeLimit;
574 /// getIfCvtDupBlockLimit - returns the target specific size limit for a
575 /// block to be considered for duplication. Any block whose size is greater
576 /// should not be duplicated to facilitate its predication.
577 unsigned getIfCvtDupBlockSizeLimit() const {
578 return IfCvtDupBlockSizeLimit;
581 /// getPrefLoopAlignment - return the preferred loop alignment.
583 unsigned getPrefLoopAlignment() const {
584 return PrefLoopAlignment;
587 /// getPreIndexedAddressParts - returns true by value, base pointer and
588 /// offset pointer and addressing mode by reference if the node's address
589 /// can be legally represented as pre-indexed load / store address.
590 virtual bool getPreIndexedAddressParts(SDNode *N, SDOperand &Base,
592 ISD::MemIndexedMode &AM,
597 /// getPostIndexedAddressParts - returns true by value, base pointer and
598 /// offset pointer and addressing mode by reference if this node can be
599 /// combined with a load / store to form a post-indexed load / store.
600 virtual bool getPostIndexedAddressParts(SDNode *N, SDNode *Op,
601 SDOperand &Base, SDOperand &Offset,
602 ISD::MemIndexedMode &AM,
607 /// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
609 virtual SDOperand getPICJumpTableRelocBase(SDOperand Table,
610 SelectionDAG &DAG) const;
612 //===--------------------------------------------------------------------===//
613 // TargetLowering Optimization Methods
616 /// TargetLoweringOpt - A convenience struct that encapsulates a DAG, and two
617 /// SDOperands for returning information from TargetLowering to its clients
618 /// that want to combine
619 struct TargetLoweringOpt {
625 explicit TargetLoweringOpt(SelectionDAG &InDAG, bool afterLegalize)
626 : DAG(InDAG), AfterLegalize(afterLegalize) {}
628 bool CombineTo(SDOperand O, SDOperand N) {
634 /// ShrinkDemandedConstant - Check to see if the specified operand of the
635 /// specified instruction is a constant integer. If so, check to see if
636 /// there are any bits set in the constant that are not demanded. If so,
637 /// shrink the constant and return true.
638 bool ShrinkDemandedConstant(SDOperand Op, const APInt &Demanded);
641 /// SimplifyDemandedBits - Look at Op. At this point, we know that only the
642 /// DemandedMask bits of the result of Op are ever used downstream. If we can
643 /// use this information to simplify Op, create a new simplified DAG node and
644 /// return true, returning the original and new nodes in Old and New.
645 /// Otherwise, analyze the expression and return a mask of KnownOne and
646 /// KnownZero bits for the expression (used to simplify the caller).
647 /// The KnownZero/One bits may only be accurate for those bits in the
649 bool SimplifyDemandedBits(SDOperand Op, const APInt &DemandedMask,
650 APInt &KnownZero, APInt &KnownOne,
651 TargetLoweringOpt &TLO, unsigned Depth = 0) const;
653 /// computeMaskedBitsForTargetNode - Determine which of the bits specified in
654 /// Mask are known to be either zero or one and return them in the
655 /// KnownZero/KnownOne bitsets.
656 virtual void computeMaskedBitsForTargetNode(const SDOperand Op,
660 const SelectionDAG &DAG,
661 unsigned Depth = 0) const;
663 /// ComputeNumSignBitsForTargetNode - This method can be implemented by
664 /// targets that want to expose additional information about sign bits to the
666 virtual unsigned ComputeNumSignBitsForTargetNode(SDOperand Op,
667 unsigned Depth = 0) const;
669 struct DAGCombinerInfo {
670 void *DC; // The DAG Combiner object.
672 bool CalledByLegalizer;
676 DAGCombinerInfo(SelectionDAG &dag, bool bl, bool cl, void *dc)
677 : DC(dc), BeforeLegalize(bl), CalledByLegalizer(cl), DAG(dag) {}
679 bool isBeforeLegalize() const { return BeforeLegalize; }
680 bool isCalledByLegalizer() const { return CalledByLegalizer; }
682 void AddToWorklist(SDNode *N);
683 SDOperand CombineTo(SDNode *N, const std::vector<SDOperand> &To);
684 SDOperand CombineTo(SDNode *N, SDOperand Res);
685 SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1);
688 /// SimplifySetCC - Try to simplify a setcc built with the specified operands
689 /// and cc. If it is unable to simplify it, return a null SDOperand.
690 SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
691 ISD::CondCode Cond, bool foldBooleans,
692 DAGCombinerInfo &DCI) const;
694 /// isGAPlusOffset - Returns true (and the GlobalValue and the offset) if the
695 /// node is a GlobalAddress + offset.
697 isGAPlusOffset(SDNode *N, GlobalValue* &GA, int64_t &Offset) const;
699 /// isConsecutiveLoad - Return true if LD (which must be a LoadSDNode) is
700 /// loading 'Bytes' bytes from a location that is 'Dist' units away from the
701 /// location that the 'Base' load is loading from.
702 bool isConsecutiveLoad(SDNode *LD, SDNode *Base, unsigned Bytes, int Dist,
703 const MachineFrameInfo *MFI) const;
705 /// PerformDAGCombine - This method will be invoked for all target nodes and
706 /// for any target-independent nodes that the target has registered with
709 /// The semantics are as follows:
711 /// SDOperand.Val == 0 - No change was made
712 /// SDOperand.Val == N - N was replaced, is dead, and is already handled.
713 /// otherwise - N should be replaced by the returned Operand.
715 /// In addition, methods provided by DAGCombinerInfo may be used to perform
716 /// more complex transformations.
718 virtual SDOperand PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const;
720 //===--------------------------------------------------------------------===//
721 // TargetLowering Configuration Methods - These methods should be invoked by
722 // the derived class constructor to configure this object for the target.
726 /// setUsesGlobalOffsetTable - Specify that this target does or doesn't use a
727 /// GOT for PC-relative code.
728 void setUsesGlobalOffsetTable(bool V) { UsesGlobalOffsetTable = V; }
730 /// setShiftAmountType - Describe the type that should be used for shift
731 /// amounts. This type defaults to the pointer type.
732 void setShiftAmountType(MVT::ValueType VT) { ShiftAmountTy = VT; }
734 /// setSetCCResultContents - Specify how the target extends the result of a
735 /// setcc operation in a register.
736 void setSetCCResultContents(SetCCResultValue Ty) { SetCCResultContents = Ty; }
738 /// setSchedulingPreference - Specify the target scheduling preference.
739 void setSchedulingPreference(SchedPreference Pref) {
740 SchedPreferenceInfo = Pref;
743 /// setShiftAmountFlavor - Describe how the target handles out of range shift
745 void setShiftAmountFlavor(OutOfRangeShiftAmount OORSA) {
746 ShiftAmtHandling = OORSA;
749 /// setUseUnderscoreSetJmp - Indicate whether this target prefers to
750 /// use _setjmp to implement llvm.setjmp or the non _ version.
751 /// Defaults to false.
752 void setUseUnderscoreSetJmp(bool Val) {
753 UseUnderscoreSetJmp = Val;
756 /// setUseUnderscoreLongJmp - Indicate whether this target prefers to
757 /// use _longjmp to implement llvm.longjmp or the non _ version.
758 /// Defaults to false.
759 void setUseUnderscoreLongJmp(bool Val) {
760 UseUnderscoreLongJmp = Val;
763 /// setStackPointerRegisterToSaveRestore - If set to a physical register, this
764 /// specifies the register that llvm.savestack/llvm.restorestack should save
766 void setStackPointerRegisterToSaveRestore(unsigned R) {
767 StackPointerRegisterToSaveRestore = R;
770 /// setExceptionPointerRegister - If set to a physical register, this sets
771 /// the register that receives the exception address on entry to a landing
773 void setExceptionPointerRegister(unsigned R) {
774 ExceptionPointerRegister = R;
777 /// setExceptionSelectorRegister - If set to a physical register, this sets
778 /// the register that receives the exception typeid on entry to a landing
780 void setExceptionSelectorRegister(unsigned R) {
781 ExceptionSelectorRegister = R;
784 /// SelectIsExpensive - Tells the code generator not to expand operations
785 /// into sequences that use the select operations if possible.
786 void setSelectIsExpensive() { SelectIsExpensive = true; }
788 /// setIntDivIsCheap - Tells the code generator that integer divide is
789 /// expensive, and if possible, should be replaced by an alternate sequence
790 /// of instructions not containing an integer divide.
791 void setIntDivIsCheap(bool isCheap = true) { IntDivIsCheap = isCheap; }
793 /// setPow2DivIsCheap - Tells the code generator that it shouldn't generate
794 /// srl/add/sra for a signed divide by power of two, and let the target handle
796 void setPow2DivIsCheap(bool isCheap = true) { Pow2DivIsCheap = isCheap; }
798 /// addRegisterClass - Add the specified register class as an available
799 /// regclass for the specified value type. This indicates the selector can
800 /// handle values of that class natively.
801 void addRegisterClass(MVT::ValueType VT, TargetRegisterClass *RC) {
802 assert(VT < array_lengthof(RegClassForVT));
803 AvailableRegClasses.push_back(std::make_pair(VT, RC));
804 RegClassForVT[VT] = RC;
807 /// computeRegisterProperties - Once all of the register classes are added,
808 /// this allows us to compute derived properties we expose.
809 void computeRegisterProperties();
811 /// setOperationAction - Indicate that the specified operation does not work
812 /// with the specified type and indicate what to do about it.
813 void setOperationAction(unsigned Op, MVT::ValueType VT,
814 LegalizeAction Action) {
815 assert(VT < sizeof(OpActions[0])*4 && Op < array_lengthof(OpActions) &&
816 "Table isn't big enough!");
817 OpActions[Op] &= ~(uint64_t(3UL) << VT*2);
818 OpActions[Op] |= (uint64_t)Action << VT*2;
821 /// setLoadXAction - Indicate that the specified load with extension does not
822 /// work with the with specified type and indicate what to do about it.
823 void setLoadXAction(unsigned ExtType, MVT::ValueType VT,
824 LegalizeAction Action) {
825 assert(VT < sizeof(LoadXActions[0])*4 &&
826 ExtType < array_lengthof(LoadXActions) &&
827 "Table isn't big enough!");
828 LoadXActions[ExtType] &= ~(uint64_t(3UL) << VT*2);
829 LoadXActions[ExtType] |= (uint64_t)Action << VT*2;
832 /// setTruncStoreAction - Indicate that the specified truncating store does
833 /// not work with the with specified type and indicate what to do about it.
834 void setTruncStoreAction(MVT::ValueType ValVT, MVT::ValueType MemVT,
835 LegalizeAction Action) {
836 assert(ValVT < array_lengthof(TruncStoreActions) &&
837 MemVT < sizeof(TruncStoreActions[0])*4 && "Table isn't big enough!");
838 TruncStoreActions[ValVT] &= ~(uint64_t(3UL) << MemVT*2);
839 TruncStoreActions[ValVT] |= (uint64_t)Action << MemVT*2;
842 /// setIndexedLoadAction - Indicate that the specified indexed load does or
843 /// does not work with the with specified type and indicate what to do abort
844 /// it. NOTE: All indexed mode loads are initialized to Expand in
845 /// TargetLowering.cpp
846 void setIndexedLoadAction(unsigned IdxMode, MVT::ValueType VT,
847 LegalizeAction Action) {
848 assert(VT < sizeof(IndexedModeActions[0])*4 && IdxMode <
849 array_lengthof(IndexedModeActions[0]) &&
850 "Table isn't big enough!");
851 IndexedModeActions[0][IdxMode] &= ~(uint64_t(3UL) << VT*2);
852 IndexedModeActions[0][IdxMode] |= (uint64_t)Action << VT*2;
855 /// setIndexedStoreAction - Indicate that the specified indexed store does or
856 /// does not work with the with specified type and indicate what to do about
857 /// it. NOTE: All indexed mode stores are initialized to Expand in
858 /// TargetLowering.cpp
859 void setIndexedStoreAction(unsigned IdxMode, MVT::ValueType VT,
860 LegalizeAction Action) {
861 assert(VT < sizeof(IndexedModeActions[1][0])*4 &&
862 IdxMode < array_lengthof(IndexedModeActions[1]) &&
863 "Table isn't big enough!");
864 IndexedModeActions[1][IdxMode] &= ~(uint64_t(3UL) << VT*2);
865 IndexedModeActions[1][IdxMode] |= (uint64_t)Action << VT*2;
868 /// setConvertAction - Indicate that the specified conversion does or does
869 /// not work with the with specified type and indicate what to do about it.
870 void setConvertAction(MVT::ValueType FromVT, MVT::ValueType ToVT,
871 LegalizeAction Action) {
872 assert(FromVT < array_lengthof(ConvertActions) &&
873 ToVT < sizeof(ConvertActions[0])*4 && "Table isn't big enough!");
874 ConvertActions[FromVT] &= ~(uint64_t(3UL) << ToVT*2);
875 ConvertActions[FromVT] |= (uint64_t)Action << ToVT*2;
878 /// AddPromotedToType - If Opc/OrigVT is specified as being promoted, the
879 /// promotion code defaults to trying a larger integer/fp until it can find
880 /// one that works. If that default is insufficient, this method can be used
881 /// by the target to override the default.
882 void AddPromotedToType(unsigned Opc, MVT::ValueType OrigVT,
883 MVT::ValueType DestVT) {
884 PromoteToType[std::make_pair(Opc, OrigVT)] = DestVT;
887 /// addLegalFPImmediate - Indicate that this target can instruction select
888 /// the specified FP immediate natively.
889 void addLegalFPImmediate(const APFloat& Imm) {
890 LegalFPImmediates.push_back(Imm);
893 /// setTargetDAGCombine - Targets should invoke this method for each target
894 /// independent node that they want to provide a custom DAG combiner for by
895 /// implementing the PerformDAGCombine virtual method.
896 void setTargetDAGCombine(ISD::NodeType NT) {
897 assert(unsigned(NT >> 3) < array_lengthof(TargetDAGCombineArray));
898 TargetDAGCombineArray[NT >> 3] |= 1 << (NT&7);
901 /// setJumpBufSize - Set the target's required jmp_buf buffer size (in
902 /// bytes); default is 200
903 void setJumpBufSize(unsigned Size) {
907 /// setJumpBufAlignment - Set the target's required jmp_buf buffer
908 /// alignment (in bytes); default is 0
909 void setJumpBufAlignment(unsigned Align) {
910 JumpBufAlignment = Align;
913 /// setIfCvtBlockSizeLimit - Set the target's if-conversion block size
914 /// limit (in number of instructions); default is 2.
915 void setIfCvtBlockSizeLimit(unsigned Limit) {
916 IfCvtBlockSizeLimit = Limit;
919 /// setIfCvtDupBlockSizeLimit - Set the target's block size limit (in number
920 /// of instructions) to be considered for code duplication during
921 /// if-conversion; default is 2.
922 void setIfCvtDupBlockSizeLimit(unsigned Limit) {
923 IfCvtDupBlockSizeLimit = Limit;
926 /// setPrefLoopAlignment - Set the target's preferred loop alignment. Default
927 /// alignment is zero, it means the target does not care about loop alignment.
928 void setPrefLoopAlignment(unsigned Align) {
929 PrefLoopAlignment = Align;
934 virtual const TargetSubtarget *getSubtarget() {
935 assert(0 && "Not Implemented");
936 return NULL; // this is here to silence compiler errors
938 //===--------------------------------------------------------------------===//
939 // Lowering methods - These methods must be implemented by targets so that
940 // the SelectionDAGLowering code knows how to lower these.
943 /// LowerArguments - This hook must be implemented to indicate how we should
944 /// lower the arguments for the specified function, into the specified DAG.
945 virtual std::vector<SDOperand>
946 LowerArguments(Function &F, SelectionDAG &DAG);
948 /// LowerCallTo - This hook lowers an abstract call to a function into an
949 /// actual call. This returns a pair of operands. The first element is the
950 /// return value for the function (if RetTy is not VoidTy). The second
951 /// element is the outgoing token chain.
952 struct ArgListEntry {
963 ArgListEntry() : isSExt(false), isZExt(false), isInReg(false),
964 isSRet(false), isNest(false), isByVal(false), Alignment(0) { }
966 typedef std::vector<ArgListEntry> ArgListTy;
967 virtual std::pair<SDOperand, SDOperand>
968 LowerCallTo(SDOperand Chain, const Type *RetTy, bool RetSExt, bool RetZExt,
969 bool isVarArg, unsigned CallingConv, bool isTailCall,
970 SDOperand Callee, ArgListTy &Args, SelectionDAG &DAG);
973 /// EmitTargetCodeForMemcpy - Emit target-specific code that performs a
974 /// memcpy. This can be used by targets to provide code sequences for cases
975 /// that don't fit the target's parameters for simple loads/stores and can be
976 /// more efficient than using a library call. This function can return a null
977 /// SDOperand if the target declines to use custom code and a different
978 /// lowering strategy should be used.
980 /// If AlwaysInline is true, the size is constant and the target should not
981 /// emit any calls and is strongly encouraged to attempt to emit inline code
982 /// even if it is beyond the usual threshold because this intrinsic is being
983 /// expanded in a place where calls are not feasible (e.g. within the prologue
984 /// for another call). If the target chooses to decline an AlwaysInline
985 /// request here, legalize will resort to using simple loads and stores.
987 EmitTargetCodeForMemcpy(SelectionDAG &DAG,
989 SDOperand Op1, SDOperand Op2,
990 SDOperand Op3, unsigned Align,
992 const Value *DstSV, uint64_t DstOff,
993 const Value *SrcSV, uint64_t SrcOff) {
997 /// EmitTargetCodeForMemmove - Emit target-specific code that performs a
998 /// memmove. This can be used by targets to provide code sequences for cases
999 /// that don't fit the target's parameters for simple loads/stores and can be
1000 /// more efficient than using a library call. This function can return a null
1001 /// SDOperand if the target declines to use custom code and a different
1002 /// lowering strategy should be used.
1004 EmitTargetCodeForMemmove(SelectionDAG &DAG,
1006 SDOperand Op1, SDOperand Op2,
1007 SDOperand Op3, unsigned Align,
1008 const Value *DstSV, uint64_t DstOff,
1009 const Value *SrcSV, uint64_t SrcOff) {
1013 /// EmitTargetCodeForMemset - Emit target-specific code that performs a
1014 /// memset. This can be used by targets to provide code sequences for cases
1015 /// that don't fit the target's parameters for simple stores and can be more
1016 /// efficient than using a library call. This function can return a null
1017 /// SDOperand if the target declines to use custom code and a different
1018 /// lowering strategy should be used.
1020 EmitTargetCodeForMemset(SelectionDAG &DAG,
1022 SDOperand Op1, SDOperand Op2,
1023 SDOperand Op3, unsigned Align,
1024 const Value *DstSV, uint64_t DstOff) {
1028 /// LowerOperation - This callback is invoked for operations that are
1029 /// unsupported by the target, which are registered to use 'custom' lowering,
1030 /// and whose defined values are all legal.
1031 /// If the target has no operations that require custom lowering, it need not
1032 /// implement this. The default implementation of this aborts.
1033 virtual SDOperand LowerOperation(SDOperand Op, SelectionDAG &DAG);
1035 /// ExpandOperationResult - This callback is invoked for operations that are
1036 /// unsupported by the target, which are registered to use 'custom' lowering,
1037 /// and whose result type needs to be expanded. This must return a node whose
1038 /// results precisely match the results of the input node. This typically
1039 /// involves a MERGE_VALUES node and/or BUILD_PAIR.
1041 /// If the target has no operations that require custom lowering, it need not
1042 /// implement this. The default implementation of this aborts.
1043 virtual SDNode *ExpandOperationResult(SDNode *N, SelectionDAG &DAG) {
1044 assert(0 && "ExpandOperationResult not implemented for this target!");
1048 /// IsEligibleForTailCallOptimization - Check whether the call is eligible for
1049 /// tail call optimization. Targets which want to do tail call optimization
1050 /// should override this function.
1051 virtual bool IsEligibleForTailCallOptimization(SDOperand Call,
1053 SelectionDAG &DAG) const {
1057 /// CheckTailCallReturnConstraints - Check whether CALL node immediatly
1058 /// preceeds the RET node and whether the return uses the result of the node
1059 /// or is a void return. This function can be used by the target to determine
1060 /// eligiblity of tail call optimization.
1061 static bool CheckTailCallReturnConstraints(SDOperand Call, SDOperand Ret) {
1062 unsigned NumOps = Ret.getNumOperands();
1064 (Ret.getOperand(0) == SDOperand(Call.Val,1) ||
1065 Ret.getOperand(0) == SDOperand(Call.Val,0))) ||
1067 Ret.getOperand(0) == SDOperand(Call.Val,Call.Val->getNumValues()-1) &&
1068 Ret.getOperand(1) == SDOperand(Call.Val,0)))
1073 /// GetPossiblePreceedingTailCall - Get preceeding TailCallNodeOpCode node if
1074 /// it exists skip possible ISD:TokenFactor.
1075 static SDOperand GetPossiblePreceedingTailCall(SDOperand Chain,
1076 unsigned TailCallNodeOpCode) {
1077 if (Chain.getOpcode() == TailCallNodeOpCode) {
1079 } else if (Chain.getOpcode() == ISD::TokenFactor) {
1080 if (Chain.getNumOperands() &&
1081 Chain.getOperand(0).getOpcode() == TailCallNodeOpCode)
1082 return Chain.getOperand(0);
1087 /// CustomPromoteOperation - This callback is invoked for operations that are
1088 /// unsupported by the target, are registered to use 'custom' lowering, and
1089 /// whose type needs to be promoted.
1090 virtual SDOperand CustomPromoteOperation(SDOperand Op, SelectionDAG &DAG);
1092 /// getTargetNodeName() - This method returns the name of a target specific
1094 virtual const char *getTargetNodeName(unsigned Opcode) const;
1096 //===--------------------------------------------------------------------===//
1097 // Inline Asm Support hooks
1100 enum ConstraintType {
1101 C_Register, // Constraint represents a single register.
1102 C_RegisterClass, // Constraint represents one or more registers.
1103 C_Memory, // Memory constraint.
1104 C_Other, // Something else.
1105 C_Unknown // Unsupported constraint.
1108 /// AsmOperandInfo - This contains information for each constraint that we are
1110 struct AsmOperandInfo : public InlineAsm::ConstraintInfo {
1111 /// ConstraintCode - This contains the actual string for the code, like "m".
1112 std::string ConstraintCode;
1114 /// ConstraintType - Information about the constraint code, e.g. Register,
1115 /// RegisterClass, Memory, Other, Unknown.
1116 TargetLowering::ConstraintType ConstraintType;
1118 /// CallOperandval - If this is the result output operand or a
1119 /// clobber, this is null, otherwise it is the incoming operand to the
1120 /// CallInst. This gets modified as the asm is processed.
1121 Value *CallOperandVal;
1123 /// ConstraintVT - The ValueType for the operand value.
1124 MVT::ValueType ConstraintVT;
1126 AsmOperandInfo(const InlineAsm::ConstraintInfo &info)
1127 : InlineAsm::ConstraintInfo(info),
1128 ConstraintType(TargetLowering::C_Unknown),
1129 CallOperandVal(0), ConstraintVT(MVT::Other) {
1133 /// ComputeConstraintToUse - Determines the constraint code and constraint
1134 /// type to use for the specific AsmOperandInfo, setting
1135 /// OpInfo.ConstraintCode and OpInfo.ConstraintType. If the actual operand
1136 /// being passed in is available, it can be passed in as Op, otherwise an
1137 /// empty SDOperand can be passed.
1138 virtual void ComputeConstraintToUse(AsmOperandInfo &OpInfo,
1140 SelectionDAG *DAG = 0) const;
1142 /// getConstraintType - Given a constraint, return the type of constraint it
1143 /// is for this target.
1144 virtual ConstraintType getConstraintType(const std::string &Constraint) const;
1146 /// getRegClassForInlineAsmConstraint - Given a constraint letter (e.g. "r"),
1147 /// return a list of registers that can be used to satisfy the constraint.
1148 /// This should only be used for C_RegisterClass constraints.
1149 virtual std::vector<unsigned>
1150 getRegClassForInlineAsmConstraint(const std::string &Constraint,
1151 MVT::ValueType VT) const;
1153 /// getRegForInlineAsmConstraint - Given a physical register constraint (e.g.
1154 /// {edx}), return the register number and the register class for the
1157 /// Given a register class constraint, like 'r', if this corresponds directly
1158 /// to an LLVM register class, return a register of 0 and the register class
1161 /// This should only be used for C_Register constraints. On error,
1162 /// this returns a register number of 0 and a null register class pointer..
1163 virtual std::pair<unsigned, const TargetRegisterClass*>
1164 getRegForInlineAsmConstraint(const std::string &Constraint,
1165 MVT::ValueType VT) const;
1167 /// LowerXConstraint - try to replace an X constraint, which matches anything,
1168 /// with another that has more specific requirements based on the type of the
1169 /// corresponding operand. This returns null if there is no replacement to
1171 virtual const char *LowerXConstraint(MVT::ValueType ConstraintVT) const;
1173 /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
1174 /// vector. If it is invalid, don't add anything to Ops.
1175 virtual void LowerAsmOperandForConstraint(SDOperand Op, char ConstraintLetter,
1176 std::vector<SDOperand> &Ops,
1177 SelectionDAG &DAG) const;
1179 //===--------------------------------------------------------------------===//
1183 // EmitInstrWithCustomInserter - This method should be implemented by targets
1184 // that mark instructions with the 'usesCustomDAGSchedInserter' flag. These
1185 // instructions are special in various ways, which require special support to
1186 // insert. The specified MachineInstr is created but not inserted into any
1187 // basic blocks, and the scheduler passes ownership of it to this method.
1188 virtual MachineBasicBlock *EmitInstrWithCustomInserter(MachineInstr *MI,
1189 MachineBasicBlock *MBB);
1191 //===--------------------------------------------------------------------===//
1192 // Addressing mode description hooks (used by LSR etc).
1195 /// AddrMode - This represents an addressing mode of:
1196 /// BaseGV + BaseOffs + BaseReg + Scale*ScaleReg
1197 /// If BaseGV is null, there is no BaseGV.
1198 /// If BaseOffs is zero, there is no base offset.
1199 /// If HasBaseReg is false, there is no base register.
1200 /// If Scale is zero, there is no ScaleReg. Scale of 1 indicates a reg with
1204 GlobalValue *BaseGV;
1208 AddrMode() : BaseGV(0), BaseOffs(0), HasBaseReg(false), Scale(0) {}
1211 /// isLegalAddressingMode - Return true if the addressing mode represented by
1212 /// AM is legal for this target, for a load/store of the specified type.
1213 /// TODO: Handle pre/postinc as well.
1214 virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty) const;
1216 /// isTruncateFree - Return true if it's free to truncate a value of
1217 /// type Ty1 to type Ty2. e.g. On x86 it's free to truncate a i32 value in
1218 /// register EAX to i16 by referencing its sub-register AX.
1219 virtual bool isTruncateFree(const Type *Ty1, const Type *Ty2) const {
1223 virtual bool isTruncateFree(MVT::ValueType VT1, MVT::ValueType VT2) const {
1227 //===--------------------------------------------------------------------===//
1228 // Div utility functions
1230 SDOperand BuildSDIV(SDNode *N, SelectionDAG &DAG,
1231 std::vector<SDNode*>* Created) const;
1232 SDOperand BuildUDIV(SDNode *N, SelectionDAG &DAG,
1233 std::vector<SDNode*>* Created) const;
1236 //===--------------------------------------------------------------------===//
1237 // Runtime Library hooks
1240 /// setLibcallName - Rename the default libcall routine name for the specified
1242 void setLibcallName(RTLIB::Libcall Call, const char *Name) {
1243 LibcallRoutineNames[Call] = Name;
1246 /// getLibcallName - Get the libcall routine name for the specified libcall.
1248 const char *getLibcallName(RTLIB::Libcall Call) const {
1249 return LibcallRoutineNames[Call];
1252 /// setCmpLibcallCC - Override the default CondCode to be used to test the
1253 /// result of the comparison libcall against zero.
1254 void setCmpLibcallCC(RTLIB::Libcall Call, ISD::CondCode CC) {
1255 CmpLibcallCCs[Call] = CC;
1258 /// getCmpLibcallCC - Get the CondCode that's to be used to test the result of
1259 /// the comparison libcall against zero.
1260 ISD::CondCode getCmpLibcallCC(RTLIB::Libcall Call) const {
1261 return CmpLibcallCCs[Call];
1266 const TargetData *TD;
1268 /// IsLittleEndian - True if this is a little endian target.
1270 bool IsLittleEndian;
1272 /// PointerTy - The type to use for pointers, usually i32 or i64.
1274 MVT::ValueType PointerTy;
1276 /// UsesGlobalOffsetTable - True if this target uses a GOT for PIC codegen.
1278 bool UsesGlobalOffsetTable;
1280 /// ShiftAmountTy - The type to use for shift amounts, usually i8 or whatever
1282 MVT::ValueType ShiftAmountTy;
1284 OutOfRangeShiftAmount ShiftAmtHandling;
1286 /// SelectIsExpensive - Tells the code generator not to expand operations
1287 /// into sequences that use the select operations if possible.
1288 bool SelectIsExpensive;
1290 /// IntDivIsCheap - Tells the code generator not to expand integer divides by
1291 /// constants into a sequence of muls, adds, and shifts. This is a hack until
1292 /// a real cost model is in place. If we ever optimize for size, this will be
1293 /// set to true unconditionally.
1296 /// Pow2DivIsCheap - Tells the code generator that it shouldn't generate
1297 /// srl/add/sra for a signed divide by power of two, and let the target handle
1299 bool Pow2DivIsCheap;
1301 /// SetCCResultContents - Information about the contents of the high-bits in
1302 /// the result of a setcc comparison operation.
1303 SetCCResultValue SetCCResultContents;
1305 /// SchedPreferenceInfo - The target scheduling preference: shortest possible
1306 /// total cycles or lowest register usage.
1307 SchedPreference SchedPreferenceInfo;
1309 /// UseUnderscoreSetJmp - This target prefers to use _setjmp to implement
1310 /// llvm.setjmp. Defaults to false.
1311 bool UseUnderscoreSetJmp;
1313 /// UseUnderscoreLongJmp - This target prefers to use _longjmp to implement
1314 /// llvm.longjmp. Defaults to false.
1315 bool UseUnderscoreLongJmp;
1317 /// JumpBufSize - The size, in bytes, of the target's jmp_buf buffers
1318 unsigned JumpBufSize;
1320 /// JumpBufAlignment - The alignment, in bytes, of the target's jmp_buf
1322 unsigned JumpBufAlignment;
1324 /// IfCvtBlockSizeLimit - The maximum allowed size for a block to be
1326 unsigned IfCvtBlockSizeLimit;
1328 /// IfCvtDupBlockSizeLimit - The maximum allowed size for a block to be
1329 /// duplicated during if-conversion.
1330 unsigned IfCvtDupBlockSizeLimit;
1332 /// PrefLoopAlignment - The perferred loop alignment.
1334 unsigned PrefLoopAlignment;
1336 /// StackPointerRegisterToSaveRestore - If set to a physical register, this
1337 /// specifies the register that llvm.savestack/llvm.restorestack should save
1339 unsigned StackPointerRegisterToSaveRestore;
1341 /// ExceptionPointerRegister - If set to a physical register, this specifies
1342 /// the register that receives the exception address on entry to a landing
1344 unsigned ExceptionPointerRegister;
1346 /// ExceptionSelectorRegister - If set to a physical register, this specifies
1347 /// the register that receives the exception typeid on entry to a landing
1349 unsigned ExceptionSelectorRegister;
1351 /// RegClassForVT - This indicates the default register class to use for
1352 /// each ValueType the target supports natively.
1353 TargetRegisterClass *RegClassForVT[MVT::LAST_VALUETYPE];
1354 unsigned char NumRegistersForVT[MVT::LAST_VALUETYPE];
1355 MVT::ValueType RegisterTypeForVT[MVT::LAST_VALUETYPE];
1357 /// TransformToType - For any value types we are promoting or expanding, this
1358 /// contains the value type that we are changing to. For Expanded types, this
1359 /// contains one step of the expand (e.g. i64 -> i32), even if there are
1360 /// multiple steps required (e.g. i64 -> i16). For types natively supported
1361 /// by the system, this holds the same type (e.g. i32 -> i32).
1362 MVT::ValueType TransformToType[MVT::LAST_VALUETYPE];
1364 // Defines the capacity of the TargetLowering::OpActions table
1365 static const int OpActionsCapacity = 176;
1367 /// OpActions - For each operation and each value type, keep a LegalizeAction
1368 /// that indicates how instruction selection should deal with the operation.
1369 /// Most operations are Legal (aka, supported natively by the target), but
1370 /// operations that are not should be described. Note that operations on
1371 /// non-legal value types are not described here.
1372 uint64_t OpActions[OpActionsCapacity];
1374 /// LoadXActions - For each load of load extension type and each value type,
1375 /// keep a LegalizeAction that indicates how instruction selection should deal
1377 uint64_t LoadXActions[ISD::LAST_LOADX_TYPE];
1379 /// TruncStoreActions - For each truncating store, keep a LegalizeAction that
1380 /// indicates how instruction selection should deal with the store.
1381 uint64_t TruncStoreActions[MVT::LAST_VALUETYPE];
1383 /// IndexedModeActions - For each indexed mode and each value type, keep a
1384 /// pair of LegalizeAction that indicates how instruction selection should
1385 /// deal with the load / store.
1386 uint64_t IndexedModeActions[2][ISD::LAST_INDEXED_MODE];
1388 /// ConvertActions - For each conversion from source type to destination type,
1389 /// keep a LegalizeAction that indicates how instruction selection should
1390 /// deal with the conversion.
1391 /// Currently, this is used only for floating->floating conversions
1392 /// (FP_EXTEND and FP_ROUND).
1393 uint64_t ConvertActions[MVT::LAST_VALUETYPE];
1395 ValueTypeActionImpl ValueTypeActions;
1397 std::vector<APFloat> LegalFPImmediates;
1399 std::vector<std::pair<MVT::ValueType,
1400 TargetRegisterClass*> > AvailableRegClasses;
1402 /// TargetDAGCombineArray - Targets can specify ISD nodes that they would
1403 /// like PerformDAGCombine callbacks for by calling setTargetDAGCombine(),
1404 /// which sets a bit in this array.
1406 TargetDAGCombineArray[OpActionsCapacity/(sizeof(unsigned char)*8)];
1408 /// PromoteToType - For operations that must be promoted to a specific type,
1409 /// this holds the destination type. This map should be sparse, so don't hold
1412 /// Targets add entries to this map with AddPromotedToType(..), clients access
1413 /// this with getTypeToPromoteTo(..).
1414 std::map<std::pair<unsigned, MVT::ValueType>, MVT::ValueType> PromoteToType;
1416 /// LibcallRoutineNames - Stores the name each libcall.
1418 const char *LibcallRoutineNames[RTLIB::UNKNOWN_LIBCALL];
1420 /// CmpLibcallCCs - The ISD::CondCode that should be used to test the result
1421 /// of each of the comparison libcall against zero.
1422 ISD::CondCode CmpLibcallCCs[RTLIB::UNKNOWN_LIBCALL];
1425 /// When lowering %llvm.memset this field specifies the maximum number of
1426 /// store operations that may be substituted for the call to memset. Targets
1427 /// must set this value based on the cost threshold for that target. Targets
1428 /// should assume that the memset will be done using as many of the largest
1429 /// store operations first, followed by smaller ones, if necessary, per
1430 /// alignment restrictions. For example, storing 9 bytes on a 32-bit machine
1431 /// with 16-bit alignment would result in four 2-byte stores and one 1-byte
1432 /// store. This only applies to setting a constant array of a constant size.
1433 /// @brief Specify maximum number of store instructions per memset call.
1434 unsigned maxStoresPerMemset;
1436 /// When lowering %llvm.memcpy this field specifies the maximum number of
1437 /// store operations that may be substituted for a call to memcpy. Targets
1438 /// must set this value based on the cost threshold for that target. Targets
1439 /// should assume that the memcpy will be done using as many of the largest
1440 /// store operations first, followed by smaller ones, if necessary, per
1441 /// alignment restrictions. For example, storing 7 bytes on a 32-bit machine
1442 /// with 32-bit alignment would result in one 4-byte store, a one 2-byte store
1443 /// and one 1-byte store. This only applies to copying a constant array of
1445 /// @brief Specify maximum bytes of store instructions per memcpy call.
1446 unsigned maxStoresPerMemcpy;
1448 /// When lowering %llvm.memmove this field specifies the maximum number of
1449 /// store instructions that may be substituted for a call to memmove. Targets
1450 /// must set this value based on the cost threshold for that target. Targets
1451 /// should assume that the memmove will be done using as many of the largest
1452 /// store operations first, followed by smaller ones, if necessary, per
1453 /// alignment restrictions. For example, moving 9 bytes on a 32-bit machine
1454 /// with 8-bit alignment would result in nine 1-byte stores. This only
1455 /// applies to copying a constant array of constant size.
1456 /// @brief Specify maximum bytes of store instructions per memmove call.
1457 unsigned maxStoresPerMemmove;
1459 /// This field specifies whether the target machine permits unaligned memory
1460 /// accesses. This is used, for example, to determine the size of store
1461 /// operations when copying small arrays and other similar tasks.
1462 /// @brief Indicate whether the target permits unaligned memory accesses.
1463 bool allowUnalignedMemoryAccesses;
1465 } // end llvm namespace