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7b8d4a9eef
llvm-6502/include/llvm/Target/TargetLowering.h
Dan Gohman 7b8d4a9eef Convert SimplifyDemandedMask and ShrinkDemandedConstant to use APInt. 
Change several cases in SimplifyDemandedMask that don't ever do any
simplifying to reuse the logic in ComputeMaskedBits instead of
duplicating it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47648 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-27 00:25:32 +00:00

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//===-- llvm/Target/TargetLowering.h - Target Lowering Info -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file describes how to lower LLVM code to machine code. This has two
// main components:
//
// 1. Which ValueTypes are natively supported by the target.
// 2. Which operations are supported for supported ValueTypes.
// 3. Cost thresholds for alternative implementations of certain operations.
//
// In addition it has a few other components, like information about FP
// immediates.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_TARGETLOWERING_H
#define LLVM_TARGET_TARGETLOWERING_H
#include "llvm/Constants.h"
#include "llvm/InlineAsm.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/RuntimeLibcalls.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/STLExtras.h"
#include <map>
#include <vector>
namespace llvm {
class Value;
class Function;
class TargetMachine;
class TargetData;
class TargetRegisterClass;
class SDNode;
class SDOperand;
class SelectionDAG;
class MachineBasicBlock;
class MachineInstr;
class VectorType;
class TargetSubtarget;
//===----------------------------------------------------------------------===//
/// TargetLowering - This class defines information used to lower LLVM code to
/// legal SelectionDAG operators that the target instruction selector can accept
/// natively.
///
/// This class also defines callbacks that targets must implement to lower
/// target-specific constructs to SelectionDAG operators.
///
class TargetLowering {
public:
/// LegalizeAction - This enum indicates whether operations are valid for a
/// target, and if not, what action should be used to make them valid.
enum LegalizeAction {
Legal, // The target natively supports this operation.
Promote, // This operation should be executed in a larger type.
Expand, // Try to expand this to other ops, otherwise use a libcall.
Custom // Use the LowerOperation hook to implement custom lowering.
};
enum OutOfRangeShiftAmount {
Undefined, // Oversized shift amounts are undefined (default).
Mask, // Shift amounts are auto masked (anded) to value size.
Extend // Oversized shift pulls in zeros or sign bits.
};
enum SetCCResultValue {
UndefinedSetCCResult, // SetCC returns a garbage/unknown extend.
ZeroOrOneSetCCResult, // SetCC returns a zero extended result.
ZeroOrNegativeOneSetCCResult // SetCC returns a sign extended result.
};
enum SchedPreference {
SchedulingForLatency, // Scheduling for shortest total latency.
SchedulingForRegPressure // Scheduling for lowest register pressure.
};
explicit TargetLowering(TargetMachine &TM);
virtual ~TargetLowering();
TargetMachine &getTargetMachine() const { return TM; }
const TargetData *getTargetData() const { return TD; }
bool isBigEndian() const { return !IsLittleEndian; }
bool isLittleEndian() const { return IsLittleEndian; }
MVT::ValueType getPointerTy() const { return PointerTy; }
MVT::ValueType getShiftAmountTy() const { return ShiftAmountTy; }
OutOfRangeShiftAmount getShiftAmountFlavor() const {return ShiftAmtHandling; }
/// usesGlobalOffsetTable - Return true if this target uses a GOT for PIC
/// codegen.
bool usesGlobalOffsetTable() const { return UsesGlobalOffsetTable; }
/// isSelectExpensive - Return true if the select operation is expensive for
/// this target.
bool isSelectExpensive() const { return SelectIsExpensive; }
/// isIntDivCheap() - Return true if integer divide is usually cheaper than
/// a sequence of several shifts, adds, and multiplies for this target.
bool isIntDivCheap() const { return IntDivIsCheap; }
/// isPow2DivCheap() - Return true if pow2 div is cheaper than a chain of
/// srl/add/sra.
bool isPow2DivCheap() const { return Pow2DivIsCheap; }
/// getSetCCResultTy - Return the ValueType of the result of setcc operations.
///
MVT::ValueType getSetCCResultTy() const { return SetCCResultTy; }
/// getSetCCResultContents - For targets without boolean registers, this flag
/// returns information about the contents of the high-bits in the setcc
/// result register.
SetCCResultValue getSetCCResultContents() const { return SetCCResultContents;}
/// getSchedulingPreference - Return target scheduling preference.
SchedPreference getSchedulingPreference() const {
return SchedPreferenceInfo;
}
/// getRegClassFor - Return the register class that should be used for the
/// specified value type. This may only be called on legal types.
TargetRegisterClass *getRegClassFor(MVT::ValueType VT) const {
assert(VT < array_lengthof(RegClassForVT));
TargetRegisterClass *RC = RegClassForVT[VT];
assert(RC && "This value type is not natively supported!");
return RC;
}
/// isTypeLegal - Return true if the target has native support for the
/// specified value type. This means that it has a register that directly
/// holds it without promotions or expansions.
bool isTypeLegal(MVT::ValueType VT) const {
assert(MVT::isExtendedVT(VT) || VT < array_lengthof(RegClassForVT));
return !MVT::isExtendedVT(VT) && RegClassForVT[VT] != 0;
}
class ValueTypeActionImpl {
/// ValueTypeActions - This is a bitvector that contains two bits for each
/// value type, where the two bits correspond to the LegalizeAction enum.
/// This can be queried with "getTypeAction(VT)".
uint32_t ValueTypeActions[2];
public:
ValueTypeActionImpl() {
ValueTypeActions[0] = ValueTypeActions[1] = 0;
}
ValueTypeActionImpl(const ValueTypeActionImpl &RHS) {
ValueTypeActions[0] = RHS.ValueTypeActions[0];
ValueTypeActions[1] = RHS.ValueTypeActions[1];
}
LegalizeAction getTypeAction(MVT::ValueType VT) const {
if (MVT::isExtendedVT(VT)) {
if (MVT::isVector(VT)) return Expand;
if (MVT::isInteger(VT))
// First promote to a power-of-two size, then expand if necessary.
return VT == MVT::RoundIntegerType(VT) ? Expand : Promote;
assert(0 && "Unsupported extended type!");
}
assert(VT<4*array_lengthof(ValueTypeActions)*sizeof(ValueTypeActions[0]));
return (LegalizeAction)((ValueTypeActions[VT>>4] >> ((2*VT) & 31)) & 3);
}
void setTypeAction(MVT::ValueType VT, LegalizeAction Action) {
assert(VT<4*array_lengthof(ValueTypeActions)*sizeof(ValueTypeActions[0]));
ValueTypeActions[VT>>4] |= Action << ((VT*2) & 31);
}
};
const ValueTypeActionImpl &getValueTypeActions() const {
return ValueTypeActions;
}
/// getTypeAction - Return how we should legalize values of this type, either
/// it is already legal (return 'Legal') or we need to promote it to a larger
/// type (return 'Promote'), or we need to expand it into multiple registers
/// of smaller integer type (return 'Expand'). 'Custom' is not an option.
LegalizeAction getTypeAction(MVT::ValueType VT) const {
return ValueTypeActions.getTypeAction(VT);
}
/// getTypeToTransformTo - For types supported by the target, this is an
/// identity function. For types that must be promoted to larger types, this
/// returns the larger type to promote to. For integer types that are larger
/// than the largest integer register, this contains one step in the expansion
/// to get to the smaller register. For illegal floating point types, this
/// returns the integer type to transform to.
MVT::ValueType getTypeToTransformTo(MVT::ValueType VT) const {
if (!MVT::isExtendedVT(VT)) {
assert(VT < array_lengthof(TransformToType));
MVT::ValueType NVT = TransformToType[VT];
assert(getTypeAction(NVT) != Promote &&
"Promote may not follow Expand or Promote");
return NVT;
}
if (MVT::isVector(VT))
return MVT::getVectorType(MVT::getVectorElementType(VT),
MVT::getVectorNumElements(VT) / 2);
if (MVT::isInteger(VT)) {
MVT::ValueType NVT = MVT::RoundIntegerType(VT);
if (NVT == VT)
// Size is a power of two - expand to half the size.
return MVT::getIntegerType(MVT::getSizeInBits(VT) / 2);
else
// Promote to a power of two size, avoiding multi-step promotion.
return getTypeAction(NVT) == Promote ? getTypeToTransformTo(NVT) : NVT;
}
assert(0 && "Unsupported extended type!");
}
/// getTypeToExpandTo - For types supported by the target, this is an
/// identity function. For types that must be expanded (i.e. integer types
/// that are larger than the largest integer register or illegal floating
/// point types), this returns the largest legal type it will be expanded to.
MVT::ValueType getTypeToExpandTo(MVT::ValueType VT) const {
assert(!MVT::isVector(VT));
while (true) {
switch (getTypeAction(VT)) {
case Legal:
return VT;
case Expand:
VT = getTypeToTransformTo(VT);
break;
default:
assert(false && "Type is not legal nor is it to be expanded!");
return VT;
}
}
return VT;
}
/// getVectorTypeBreakdown - Vector types are broken down into some number of
/// legal first class types. For example, MVT::v8f32 maps to 2 MVT::v4f32
/// with Altivec or SSE1, or 8 promoted MVT::f64 values with the X86 FP stack.
/// Similarly, MVT::v2i64 turns into 4 MVT::i32 values with both PPC and X86.
///
/// This method returns the number of registers needed, and the VT for each
/// register. It also returns the VT and quantity of the intermediate values
/// before they are promoted/expanded.
///
unsigned getVectorTypeBreakdown(MVT::ValueType VT,
MVT::ValueType &IntermediateVT,
unsigned &NumIntermediates,
MVT::ValueType &RegisterVT) const;
typedef std::vector<APFloat>::const_iterator legal_fpimm_iterator;
legal_fpimm_iterator legal_fpimm_begin() const {
return LegalFPImmediates.begin();
}
legal_fpimm_iterator legal_fpimm_end() const {
return LegalFPImmediates.end();
}
/// isShuffleMaskLegal - Targets can use this to indicate that they only
/// support *some* VECTOR_SHUFFLE operations, those with specific masks.
/// By default, if a target supports the VECTOR_SHUFFLE node, all mask values
/// are assumed to be legal.
virtual bool isShuffleMaskLegal(SDOperand Mask, MVT::ValueType VT) const {
return true;
}
/// isVectorClearMaskLegal - Similar to isShuffleMaskLegal. This is
/// used by Targets can use this to indicate if there is a suitable
/// VECTOR_SHUFFLE that can be used to replace a VAND with a constant
/// pool entry.
virtual bool isVectorClearMaskLegal(std::vector<SDOperand> &BVOps,
MVT::ValueType EVT,
SelectionDAG &DAG) const {
return false;
}
/// getOperationAction - Return how this operation should be treated: either
/// it is legal, needs to be promoted to a larger size, needs to be
/// expanded to some other code sequence, or the target has a custom expander
/// for it.
LegalizeAction getOperationAction(unsigned Op, MVT::ValueType VT) const {
if (MVT::isExtendedVT(VT)) return Expand;
assert(Op < array_lengthof(OpActions) &&
VT < sizeof(OpActions[0])*4 && "Table isn't big enough!");
return (LegalizeAction)((OpActions[Op] >> (2*VT)) & 3);
}
/// isOperationLegal - Return true if the specified operation is legal on this
/// target.
bool isOperationLegal(unsigned Op, MVT::ValueType VT) const {
return getOperationAction(Op, VT) == Legal ||
getOperationAction(Op, VT) == Custom;
}
/// getLoadXAction - Return how this load with extension should be treated:
/// either it is legal, needs to be promoted to a larger size, needs to be
/// expanded to some other code sequence, or the target has a custom expander
/// for it.
LegalizeAction getLoadXAction(unsigned LType, MVT::ValueType VT) const {
assert(LType < array_lengthof(LoadXActions) &&
VT < sizeof(LoadXActions[0])*4 && "Table isn't big enough!");
return (LegalizeAction)((LoadXActions[LType] >> (2*VT)) & 3);
}
/// isLoadXLegal - Return true if the specified load with extension is legal
/// on this target.
bool isLoadXLegal(unsigned LType, MVT::ValueType VT) const {
return !MVT::isExtendedVT(VT) &&
(getLoadXAction(LType, VT) == Legal ||
getLoadXAction(LType, VT) == Custom);
}
/// getTruncStoreAction - Return how this store with truncation should be
/// treated: either it is legal, needs to be promoted to a larger size, needs
/// to be expanded to some other code sequence, or the target has a custom
/// expander for it.
LegalizeAction getTruncStoreAction(MVT::ValueType ValVT,
MVT::ValueType MemVT) const {
assert(ValVT < array_lengthof(TruncStoreActions) &&
MemVT < sizeof(TruncStoreActions[0])*4 && "Table isn't big enough!");
return (LegalizeAction)((TruncStoreActions[ValVT] >> (2*MemVT)) & 3);
}
/// isTruncStoreLegal - Return true if the specified store with truncation is
/// legal on this target.
bool isTruncStoreLegal(MVT::ValueType ValVT, MVT::ValueType MemVT) const {
return !MVT::isExtendedVT(MemVT) &&
(getTruncStoreAction(ValVT, MemVT) == Legal ||
getTruncStoreAction(ValVT, MemVT) == Custom);
}
/// getIndexedLoadAction - Return how the indexed load should be treated:
/// either it is legal, needs to be promoted to a larger size, needs to be
/// expanded to some other code sequence, or the target has a custom expander
/// for it.
LegalizeAction
getIndexedLoadAction(unsigned IdxMode, MVT::ValueType VT) const {
assert(IdxMode < array_lengthof(IndexedModeActions[0]) &&
VT < sizeof(IndexedModeActions[0][0])*4 &&
"Table isn't big enough!");
return (LegalizeAction)((IndexedModeActions[0][IdxMode] >> (2*VT)) & 3);
}
/// isIndexedLoadLegal - Return true if the specified indexed load is legal
/// on this target.
bool isIndexedLoadLegal(unsigned IdxMode, MVT::ValueType VT) const {
return getIndexedLoadAction(IdxMode, VT) == Legal ||
getIndexedLoadAction(IdxMode, VT) == Custom;
}
/// getIndexedStoreAction - Return how the indexed store should be treated:
/// either it is legal, needs to be promoted to a larger size, needs to be
/// expanded to some other code sequence, or the target has a custom expander
/// for it.
LegalizeAction
getIndexedStoreAction(unsigned IdxMode, MVT::ValueType VT) const {
assert(IdxMode < array_lengthof(IndexedModeActions[1]) &&
VT < sizeof(IndexedModeActions[1][0])*4 &&
"Table isn't big enough!");
return (LegalizeAction)((IndexedModeActions[1][IdxMode] >> (2*VT)) & 3);
}
/// isIndexedStoreLegal - Return true if the specified indexed load is legal
/// on this target.
bool isIndexedStoreLegal(unsigned IdxMode, MVT::ValueType VT) const {
return getIndexedStoreAction(IdxMode, VT) == Legal ||
getIndexedStoreAction(IdxMode, VT) == Custom;
}
/// getConvertAction - Return how the conversion should be treated:
/// either it is legal, needs to be promoted to a larger size, needs to be
/// expanded to some other code sequence, or the target has a custom expander
/// for it.
LegalizeAction
getConvertAction(MVT::ValueType FromVT, MVT::ValueType ToVT) const {
assert(FromVT < array_lengthof(ConvertActions) &&
ToVT < sizeof(ConvertActions[0])*4 && "Table isn't big enough!");
return (LegalizeAction)((ConvertActions[FromVT] >> (2*ToVT)) & 3);
}
/// isConvertLegal - Return true if the specified conversion is legal
/// on this target.
bool isConvertLegal(MVT::ValueType FromVT, MVT::ValueType ToVT) const {
return getConvertAction(FromVT, ToVT) == Legal ||
getConvertAction(FromVT, ToVT) == Custom;
}
/// getTypeToPromoteTo - If the action for this operation is to promote, this
/// method returns the ValueType to promote to.
MVT::ValueType getTypeToPromoteTo(unsigned Op, MVT::ValueType VT) const {
assert(getOperationAction(Op, VT) == Promote &&
"This operation isn't promoted!");
// See if this has an explicit type specified.
std::map<std::pair<unsigned, MVT::ValueType>,
MVT::ValueType>::const_iterator PTTI =
PromoteToType.find(std::make_pair(Op, VT));
if (PTTI != PromoteToType.end()) return PTTI->second;
assert((MVT::isInteger(VT) || MVT::isFloatingPoint(VT)) &&
"Cannot autopromote this type, add it with AddPromotedToType.");
MVT::ValueType NVT = VT;
do {
NVT = (MVT::ValueType)(NVT+1);
assert(MVT::isInteger(NVT) == MVT::isInteger(VT) && NVT != MVT::isVoid &&
"Didn't find type to promote to!");
} while (!isTypeLegal(NVT) ||
getOperationAction(Op, NVT) == Promote);
return NVT;
}
/// getValueType - Return the MVT::ValueType corresponding to this LLVM type.
/// This is fixed by the LLVM operations except for the pointer size. If
/// AllowUnknown is true, this will return MVT::Other for types with no MVT
/// counterpart (e.g. structs), otherwise it will assert.
MVT::ValueType getValueType(const Type *Ty, bool AllowUnknown = false) const {
MVT::ValueType VT = MVT::getValueType(Ty, AllowUnknown);
return VT == MVT::iPTR ? PointerTy : VT;
}
/// getByValTypeAlignment - Return the desired alignment for ByVal aggregate
/// function arguments in the caller parameter area.
virtual unsigned getByValTypeAlignment(const Type *Ty) const;
/// getRegisterType - Return the type of registers that this ValueType will
/// eventually require.
MVT::ValueType getRegisterType(MVT::ValueType VT) const {
if (!MVT::isExtendedVT(VT)) {
assert(VT < array_lengthof(RegisterTypeForVT));
return RegisterTypeForVT[VT];
}
if (MVT::isVector(VT)) {
MVT::ValueType VT1, RegisterVT;
unsigned NumIntermediates;
(void)getVectorTypeBreakdown(VT, VT1, NumIntermediates, RegisterVT);
return RegisterVT;
}
if (MVT::isInteger(VT)) {
return getRegisterType(getTypeToTransformTo(VT));
}
assert(0 && "Unsupported extended type!");
}
/// getNumRegisters - Return the number of registers that this ValueType will
/// eventually require. This is one for any types promoted to live in larger
/// registers, but may be more than one for types (like i64) that are split
/// into pieces. For types like i140, which are first promoted then expanded,
/// it is the number of registers needed to hold all the bits of the original
/// type. For an i140 on a 32 bit machine this means 5 registers.
unsigned getNumRegisters(MVT::ValueType VT) const {
if (!MVT::isExtendedVT(VT)) {
assert(VT < array_lengthof(NumRegistersForVT));
return NumRegistersForVT[VT];
}
if (MVT::isVector(VT)) {
MVT::ValueType VT1, VT2;
unsigned NumIntermediates;
return getVectorTypeBreakdown(VT, VT1, NumIntermediates, VT2);
}
if (MVT::isInteger(VT)) {
unsigned BitWidth = MVT::getSizeInBits(VT);
unsigned RegWidth = MVT::getSizeInBits(getRegisterType(VT));
return (BitWidth + RegWidth - 1) / RegWidth;
}
assert(0 && "Unsupported extended type!");
}
/// hasTargetDAGCombine - If true, the target has custom DAG combine
/// transformations that it can perform for the specified node.
bool hasTargetDAGCombine(ISD::NodeType NT) const {
assert(unsigned(NT >> 3) < array_lengthof(TargetDAGCombineArray));
return TargetDAGCombineArray[NT >> 3] & (1 << (NT&7));
}
/// This function returns the maximum number of store operations permitted
/// to replace a call to llvm.memset. The value is set by the target at the
/// performance threshold for such a replacement.
/// @brief Get maximum # of store operations permitted for llvm.memset
unsigned getMaxStoresPerMemset() const { return maxStoresPerMemset; }
/// This function returns the maximum number of store operations permitted
/// to replace a call to llvm.memcpy. The value is set by the target at the
/// performance threshold for such a replacement.
/// @brief Get maximum # of store operations permitted for llvm.memcpy
unsigned getMaxStoresPerMemcpy() const { return maxStoresPerMemcpy; }
/// This function returns the maximum number of store operations permitted
/// to replace a call to llvm.memmove. The value is set by the target at the
/// performance threshold for such a replacement.
/// @brief Get maximum # of store operations permitted for llvm.memmove
unsigned getMaxStoresPerMemmove() const { return maxStoresPerMemmove; }
/// This function returns true if the target allows unaligned memory accesses.
/// This is used, for example, in situations where an array copy/move/set is
/// converted to a sequence of store operations. It's use helps to ensure that
/// such replacements don't generate code that causes an alignment error
/// (trap) on the target machine.
/// @brief Determine if the target supports unaligned memory accesses.
bool allowsUnalignedMemoryAccesses() const {
return allowUnalignedMemoryAccesses;
}
/// usesUnderscoreSetJmp - Determine if we should use _setjmp or setjmp
/// to implement llvm.setjmp.
bool usesUnderscoreSetJmp() const {
return UseUnderscoreSetJmp;
}
/// usesUnderscoreLongJmp - Determine if we should use _longjmp or longjmp
/// to implement llvm.longjmp.
bool usesUnderscoreLongJmp() const {
return UseUnderscoreLongJmp;
}
/// getStackPointerRegisterToSaveRestore - If a physical register, this
/// specifies the register that llvm.savestack/llvm.restorestack should save
/// and restore.
unsigned getStackPointerRegisterToSaveRestore() const {
return StackPointerRegisterToSaveRestore;
}
/// getExceptionAddressRegister - If a physical register, this returns
/// the register that receives the exception address on entry to a landing
/// pad.
unsigned getExceptionAddressRegister() const {
return ExceptionPointerRegister;
}
/// getExceptionSelectorRegister - If a physical register, this returns
/// the register that receives the exception typeid on entry to a landing
/// pad.
unsigned getExceptionSelectorRegister() const {
return ExceptionSelectorRegister;
}
/// getJumpBufSize - returns the target's jmp_buf size in bytes (if never
/// set, the default is 200)
unsigned getJumpBufSize() const {
return JumpBufSize;
}
/// getJumpBufAlignment - returns the target's jmp_buf alignment in bytes
/// (if never set, the default is 0)
unsigned getJumpBufAlignment() const {
return JumpBufAlignment;
}
/// getIfCvtBlockLimit - returns the target specific if-conversion block size
/// limit. Any block whose size is greater should not be predicated.
virtual unsigned getIfCvtBlockSizeLimit() const {
return IfCvtBlockSizeLimit;
}
/// getIfCvtDupBlockLimit - returns the target specific size limit for a
/// block to be considered for duplication. Any block whose size is greater
/// should not be duplicated to facilitate its predication.
virtual unsigned getIfCvtDupBlockSizeLimit() const {
return IfCvtDupBlockSizeLimit;
}
/// getPreIndexedAddressParts - returns true by value, base pointer and
/// offset pointer and addressing mode by reference if the node's address
/// can be legally represented as pre-indexed load / store address.
virtual bool getPreIndexedAddressParts(SDNode *N, SDOperand &Base,
SDOperand &Offset,
ISD::MemIndexedMode &AM,
SelectionDAG &DAG) {
return false;
}
/// getPostIndexedAddressParts - returns true by value, base pointer and
/// offset pointer and addressing mode by reference if this node can be
/// combined with a load / store to form a post-indexed load / store.
virtual bool getPostIndexedAddressParts(SDNode *N, SDNode *Op,
SDOperand &Base, SDOperand &Offset,
ISD::MemIndexedMode &AM,
SelectionDAG &DAG) {
return false;
}
/// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
/// jumptable.
virtual SDOperand getPICJumpTableRelocBase(SDOperand Table,
SelectionDAG &DAG) const;
//===--------------------------------------------------------------------===//
// TargetLowering Optimization Methods
//
/// TargetLoweringOpt - A convenience struct that encapsulates a DAG, and two
/// SDOperands for returning information from TargetLowering to its clients
/// that want to combine
struct TargetLoweringOpt {
SelectionDAG &DAG;
bool AfterLegalize;
SDOperand Old;
SDOperand New;
explicit TargetLoweringOpt(SelectionDAG &InDAG, bool afterLegalize)
: DAG(InDAG), AfterLegalize(afterLegalize) {}
bool CombineTo(SDOperand O, SDOperand N) {
Old = O;
New = N;
return true;
}
/// ShrinkDemandedConstant - Check to see if the specified operand of the
/// specified instruction is a constant integer. If so, check to see if
/// there are any bits set in the constant that are not demanded. If so,
/// shrink the constant and return true.
bool ShrinkDemandedConstant(SDOperand Op, const APInt &Demanded);
};
/// SimplifyDemandedBits - Look at Op. At this point, we know that only the
/// DemandedMask bits of the result of Op are ever used downstream. If we can
/// use this information to simplify Op, create a new simplified DAG node and
/// return true, returning the original and new nodes in Old and New.
/// Otherwise, analyze the expression and return a mask of KnownOne and
/// KnownZero bits for the expression (used to simplify the caller).
/// The KnownZero/One bits may only be accurate for those bits in the
/// DemandedMask.
bool SimplifyDemandedBits(SDOperand Op, const APInt &DemandedMask,
APInt &KnownZero, APInt &KnownOne,
TargetLoweringOpt &TLO, unsigned Depth = 0) const;
/// computeMaskedBitsForTargetNode - Determine which of the bits specified in
/// Mask are known to be either zero or one and return them in the
/// KnownZero/KnownOne bitsets.
virtual void computeMaskedBitsForTargetNode(const SDOperand Op,
const APInt &Mask,
APInt &KnownZero,
APInt &KnownOne,
const SelectionDAG &DAG,
unsigned Depth = 0) const;
/// ComputeNumSignBitsForTargetNode - This method can be implemented by
/// targets that want to expose additional information about sign bits to the
/// DAG Combiner.
virtual unsigned ComputeNumSignBitsForTargetNode(SDOperand Op,
unsigned Depth = 0) const;
struct DAGCombinerInfo {
void *DC; // The DAG Combiner object.
bool BeforeLegalize;
bool CalledByLegalizer;
public:
SelectionDAG &DAG;
DAGCombinerInfo(SelectionDAG &dag, bool bl, bool cl, void *dc)
: DC(dc), BeforeLegalize(bl), CalledByLegalizer(cl), DAG(dag) {}
bool isBeforeLegalize() const { return BeforeLegalize; }
bool isCalledByLegalizer() const { return CalledByLegalizer; }
void AddToWorklist(SDNode *N);
SDOperand CombineTo(SDNode *N, const std::vector<SDOperand> &To);
SDOperand CombineTo(SDNode *N, SDOperand Res);
SDOperand CombineTo(SDNode *N, SDOperand Res0, SDOperand Res1);
};
/// SimplifySetCC - Try to simplify a setcc built with the specified operands
/// and cc. If it is unable to simplify it, return a null SDOperand.
SDOperand SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
ISD::CondCode Cond, bool foldBooleans,
DAGCombinerInfo &DCI) const;
/// PerformDAGCombine - This method will be invoked for all target nodes and
/// for any target-independent nodes that the target has registered with
/// invoke it for.
///
/// The semantics are as follows:
/// Return Value:
/// SDOperand.Val == 0 - No change was made
/// SDOperand.Val == N - N was replaced, is dead, and is already handled.
/// otherwise - N should be replaced by the returned Operand.
///
/// In addition, methods provided by DAGCombinerInfo may be used to perform
/// more complex transformations.
///
virtual SDOperand PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const;
//===--------------------------------------------------------------------===//
// TargetLowering Configuration Methods - These methods should be invoked by
// the derived class constructor to configure this object for the target.
//
protected:
/// setUsesGlobalOffsetTable - Specify that this target does or doesn't use a
/// GOT for PC-relative code.
void setUsesGlobalOffsetTable(bool V) { UsesGlobalOffsetTable = V; }
/// setShiftAmountType - Describe the type that should be used for shift
/// amounts. This type defaults to the pointer type.
void setShiftAmountType(MVT::ValueType VT) { ShiftAmountTy = VT; }
/// setSetCCResultType - Describe the type that shoudl be used as the result
/// of a setcc operation. This defaults to the pointer type.
void setSetCCResultType(MVT::ValueType VT) { SetCCResultTy = VT; }
/// setSetCCResultContents - Specify how the target extends the result of a
/// setcc operation in a register.
void setSetCCResultContents(SetCCResultValue Ty) { SetCCResultContents = Ty; }
/// setSchedulingPreference - Specify the target scheduling preference.
void setSchedulingPreference(SchedPreference Pref) {
SchedPreferenceInfo = Pref;
}
/// setShiftAmountFlavor - Describe how the target handles out of range shift
/// amounts.
void setShiftAmountFlavor(OutOfRangeShiftAmount OORSA) {
ShiftAmtHandling = OORSA;
}
/// setUseUnderscoreSetJmp - Indicate whether this target prefers to
/// use _setjmp to implement llvm.setjmp or the non _ version.
/// Defaults to false.
void setUseUnderscoreSetJmp(bool Val) {
UseUnderscoreSetJmp = Val;
}
/// setUseUnderscoreLongJmp - Indicate whether this target prefers to
/// use _longjmp to implement llvm.longjmp or the non _ version.
/// Defaults to false.
void setUseUnderscoreLongJmp(bool Val) {
UseUnderscoreLongJmp = Val;
}
/// setStackPointerRegisterToSaveRestore - If set to a physical register, this
/// specifies the register that llvm.savestack/llvm.restorestack should save
/// and restore.
void setStackPointerRegisterToSaveRestore(unsigned R) {
StackPointerRegisterToSaveRestore = R;
}
/// setExceptionPointerRegister - If set to a physical register, this sets
/// the register that receives the exception address on entry to a landing
/// pad.
void setExceptionPointerRegister(unsigned R) {
ExceptionPointerRegister = R;
}
/// setExceptionSelectorRegister - If set to a physical register, this sets
/// the register that receives the exception typeid on entry to a landing
/// pad.
void setExceptionSelectorRegister(unsigned R) {
ExceptionSelectorRegister = R;
}
/// SelectIsExpensive - Tells the code generator not to expand operations
/// into sequences that use the select operations if possible.
void setSelectIsExpensive() { SelectIsExpensive = true; }
/// setIntDivIsCheap - Tells the code generator that integer divide is
/// expensive, and if possible, should be replaced by an alternate sequence
/// of instructions not containing an integer divide.
void setIntDivIsCheap(bool isCheap = true) { IntDivIsCheap = isCheap; }
/// setPow2DivIsCheap - Tells the code generator that it shouldn't generate
/// srl/add/sra for a signed divide by power of two, and let the target handle
/// it.
void setPow2DivIsCheap(bool isCheap = true) { Pow2DivIsCheap = isCheap; }
/// addRegisterClass - Add the specified register class as an available
/// regclass for the specified value type. This indicates the selector can
/// handle values of that class natively.
void addRegisterClass(MVT::ValueType VT, TargetRegisterClass *RC) {
assert(VT < array_lengthof(RegClassForVT));
AvailableRegClasses.push_back(std::make_pair(VT, RC));
RegClassForVT[VT] = RC;
}
/// computeRegisterProperties - Once all of the register classes are added,
/// this allows us to compute derived properties we expose.
void computeRegisterProperties();
/// setOperationAction - Indicate that the specified operation does not work
/// with the specified type and indicate what to do about it.
void setOperationAction(unsigned Op, MVT::ValueType VT,
LegalizeAction Action) {
assert(VT < sizeof(OpActions[0])*4 && Op < array_lengthof(OpActions) &&
"Table isn't big enough!");
OpActions[Op] &= ~(uint64_t(3UL) << VT*2);
OpActions[Op] |= (uint64_t)Action << VT*2;
}
/// setLoadXAction - Indicate that the specified load with extension does not
/// work with the with specified type and indicate what to do about it.
void setLoadXAction(unsigned ExtType, MVT::ValueType VT,
LegalizeAction Action) {
assert(VT < sizeof(LoadXActions[0])*4 &&
ExtType < array_lengthof(LoadXActions) &&
"Table isn't big enough!");
LoadXActions[ExtType] &= ~(uint64_t(3UL) << VT*2);
LoadXActions[ExtType] |= (uint64_t)Action << VT*2;
}
/// setTruncStoreAction - Indicate that the specified truncating store does
/// not work with the with specified type and indicate what to do about it.
void setTruncStoreAction(MVT::ValueType ValVT, MVT::ValueType MemVT,
LegalizeAction Action) {
assert(ValVT < array_lengthof(TruncStoreActions) &&
MemVT < sizeof(TruncStoreActions[0])*4 && "Table isn't big enough!");
TruncStoreActions[ValVT] &= ~(uint64_t(3UL) << MemVT*2);
TruncStoreActions[ValVT] |= (uint64_t)Action << MemVT*2;
}
/// setIndexedLoadAction - Indicate that the specified indexed load does or
/// does not work with the with specified type and indicate what to do abort
/// it. NOTE: All indexed mode loads are initialized to Expand in
/// TargetLowering.cpp
void setIndexedLoadAction(unsigned IdxMode, MVT::ValueType VT,
LegalizeAction Action) {
assert(VT < sizeof(IndexedModeActions[0])*4 && IdxMode <
array_lengthof(IndexedModeActions[0]) &&
"Table isn't big enough!");
IndexedModeActions[0][IdxMode] &= ~(uint64_t(3UL) << VT*2);
IndexedModeActions[0][IdxMode] |= (uint64_t)Action << VT*2;
}
/// setIndexedStoreAction - Indicate that the specified indexed store does or
/// does not work with the with specified type and indicate what to do about
/// it. NOTE: All indexed mode stores are initialized to Expand in
/// TargetLowering.cpp
void setIndexedStoreAction(unsigned IdxMode, MVT::ValueType VT,
LegalizeAction Action) {
assert(VT < sizeof(IndexedModeActions[1][0])*4 &&
IdxMode < array_lengthof(IndexedModeActions[1]) &&
"Table isn't big enough!");
IndexedModeActions[1][IdxMode] &= ~(uint64_t(3UL) << VT*2);
IndexedModeActions[1][IdxMode] |= (uint64_t)Action << VT*2;
}
/// setConvertAction - Indicate that the specified conversion does or does
/// not work with the with specified type and indicate what to do about it.
void setConvertAction(MVT::ValueType FromVT, MVT::ValueType ToVT,
LegalizeAction Action) {
assert(FromVT < array_lengthof(ConvertActions) &&
ToVT < sizeof(ConvertActions[0])*4 && "Table isn't big enough!");
ConvertActions[FromVT] &= ~(uint64_t(3UL) << ToVT*2);
ConvertActions[FromVT] |= (uint64_t)Action << ToVT*2;
}
/// AddPromotedToType - If Opc/OrigVT is specified as being promoted, the
/// promotion code defaults to trying a larger integer/fp until it can find
/// one that works. If that default is insufficient, this method can be used
/// by the target to override the default.
void AddPromotedToType(unsigned Opc, MVT::ValueType OrigVT,
MVT::ValueType DestVT) {
PromoteToType[std::make_pair(Opc, OrigVT)] = DestVT;
}
/// addLegalFPImmediate - Indicate that this target can instruction select
/// the specified FP immediate natively.
void addLegalFPImmediate(const APFloat& Imm) {
LegalFPImmediates.push_back(Imm);
}
/// setTargetDAGCombine - Targets should invoke this method for each target
/// independent node that they want to provide a custom DAG combiner for by
/// implementing the PerformDAGCombine virtual method.
void setTargetDAGCombine(ISD::NodeType NT) {
assert(unsigned(NT >> 3) < array_lengthof(TargetDAGCombineArray));
TargetDAGCombineArray[NT >> 3] |= 1 << (NT&7);
}
/// setJumpBufSize - Set the target's required jmp_buf buffer size (in
/// bytes); default is 200
void setJumpBufSize(unsigned Size) {
JumpBufSize = Size;
}
/// setJumpBufAlignment - Set the target's required jmp_buf buffer
/// alignment (in bytes); default is 0
void setJumpBufAlignment(unsigned Align) {
JumpBufAlignment = Align;
}
/// setIfCvtBlockSizeLimit - Set the target's if-conversion block size
/// limit (in number of instructions); default is 2.
void setIfCvtBlockSizeLimit(unsigned Limit) {
IfCvtBlockSizeLimit = Limit;
}
/// setIfCvtDupBlockSizeLimit - Set the target's block size limit (in number
/// of instructions) to be considered for code duplication during
/// if-conversion; default is 2.
void setIfCvtDupBlockSizeLimit(unsigned Limit) {
IfCvtDupBlockSizeLimit = Limit;
}
public:
virtual const TargetSubtarget *getSubtarget() {
assert(0 && "Not Implemented");
return NULL; // this is here to silence compiler errors
}
//===--------------------------------------------------------------------===//
// Lowering methods - These methods must be implemented by targets so that
// the SelectionDAGLowering code knows how to lower these.
//
/// LowerArguments - This hook must be implemented to indicate how we should
/// lower the arguments for the specified function, into the specified DAG.
virtual std::vector<SDOperand>
LowerArguments(Function &F, SelectionDAG &DAG);
/// LowerCallTo - This hook lowers an abstract call to a function into an
/// actual call. This returns a pair of operands. The first element is the
/// return value for the function (if RetTy is not VoidTy). The second
/// element is the outgoing token chain.
struct ArgListEntry {
SDOperand Node;
const Type* Ty;
bool isSExt;
bool isZExt;
bool isInReg;
bool isSRet;
bool isNest;
bool isByVal;
uint16_t Alignment;
ArgListEntry() : isSExt(false), isZExt(false), isInReg(false),
isSRet(false), isNest(false), isByVal(false), Alignment(0) { }
};
typedef std::vector<ArgListEntry> ArgListTy;
virtual std::pair<SDOperand, SDOperand>
LowerCallTo(SDOperand Chain, const Type *RetTy, bool RetSExt, bool RetZExt,
bool isVarArg, unsigned CallingConv, bool isTailCall,
SDOperand Callee, ArgListTy &Args, SelectionDAG &DAG);
virtual SDOperand LowerMEMCPY(SDOperand Op, SelectionDAG &DAG);
virtual SDOperand LowerMEMCPYCall(SDOperand Chain, SDOperand Dest,
SDOperand Source, SDOperand Count,
SelectionDAG &DAG);
virtual SDOperand LowerMEMCPYInline(SDOperand Chain, SDOperand Dest,
SDOperand Source, unsigned Size,
unsigned Align, SelectionDAG &DAG) {
assert(0 && "Not Implemented");
return SDOperand(); // this is here to silence compiler errors
}
/// LowerOperation - This callback is invoked for operations that are
/// unsupported by the target, which are registered to use 'custom' lowering,
/// and whose defined values are all legal.
/// If the target has no operations that require custom lowering, it need not
/// implement this. The default implementation of this aborts.
virtual SDOperand LowerOperation(SDOperand Op, SelectionDAG &DAG);
/// ExpandOperationResult - This callback is invoked for operations that are
/// unsupported by the target, which are registered to use 'custom' lowering,
/// and whose result type needs to be expanded. This must return a node whose
/// results precisely match the results of the input node. This typically
/// involves a MERGE_VALUES node and/or BUILD_PAIR.
///
/// If the target has no operations that require custom lowering, it need not
/// implement this. The default implementation of this aborts.
virtual SDNode *ExpandOperationResult(SDNode *N, SelectionDAG &DAG) {
assert(0 && "ExpandOperationResult not implemented for this target!");
return 0;
}
/// IsEligibleForTailCallOptimization - Check whether the call is eligible for
/// tail call optimization. Targets which want to do tail call optimization
/// should override this function.
virtual bool IsEligibleForTailCallOptimization(SDOperand Call,
SDOperand Ret,
SelectionDAG &DAG) const {
return false;
}
/// CustomPromoteOperation - This callback is invoked for operations that are
/// unsupported by the target, are registered to use 'custom' lowering, and
/// whose type needs to be promoted.
virtual SDOperand CustomPromoteOperation(SDOperand Op, SelectionDAG &DAG);
/// getTargetNodeName() - This method returns the name of a target specific
/// DAG node.
virtual const char *getTargetNodeName(unsigned Opcode) const;
//===--------------------------------------------------------------------===//
// Inline Asm Support hooks
//
enum ConstraintType {
C_Register, // Constraint represents a single register.
C_RegisterClass, // Constraint represents one or more registers.
C_Memory, // Memory constraint.
C_Other, // Something else.
C_Unknown // Unsupported constraint.
};
/// AsmOperandInfo - This contains information for each constraint that we are
/// lowering.
struct AsmOperandInfo : public InlineAsm::ConstraintInfo {
/// ConstraintCode - This contains the actual string for the code, like "m".
std::string ConstraintCode;
/// ConstraintType - Information about the constraint code, e.g. Register,
/// RegisterClass, Memory, Other, Unknown.
TargetLowering::ConstraintType ConstraintType;
/// CallOperandval - If this is the result output operand or a
/// clobber, this is null, otherwise it is the incoming operand to the
/// CallInst. This gets modified as the asm is processed.
Value *CallOperandVal;
/// ConstraintVT - The ValueType for the operand value.
MVT::ValueType ConstraintVT;
AsmOperandInfo(const InlineAsm::ConstraintInfo &info)
: InlineAsm::ConstraintInfo(info),
ConstraintType(TargetLowering::C_Unknown),
CallOperandVal(0), ConstraintVT(MVT::Other) {
}
/// getConstraintGenerality - Return an integer indicating how general CT is.
unsigned getConstraintGenerality(TargetLowering::ConstraintType CT) {
switch (CT) {
default: assert(0 && "Unknown constraint type!");
case TargetLowering::C_Other:
case TargetLowering::C_Unknown:
return 0;
case TargetLowering::C_Register:
return 1;
case TargetLowering::C_RegisterClass:
return 2;
case TargetLowering::C_Memory:
return 3;
}
}
/// ComputeConstraintToUse - Determines the constraint code and constraint
/// type to use.
void ComputeConstraintToUse(const TargetLowering &TLI) {
assert(!Codes.empty() && "Must have at least one constraint");
std::string *Current = &Codes[0];
TargetLowering::ConstraintType CurType = TLI.getConstraintType(*Current);
if (Codes.size() == 1) { // Single-letter constraints ('r') are very common.
ConstraintCode = *Current;
ConstraintType = CurType;
} else {
unsigned CurGenerality = getConstraintGenerality(CurType);
// If we have multiple constraints, try to pick the most general one ahead
// of time. This isn't a wonderful solution, but handles common cases.
for (unsigned j = 1, e = Codes.size(); j != e; ++j) {
TargetLowering::ConstraintType ThisType = TLI.getConstraintType(Codes[j]);
unsigned ThisGenerality = getConstraintGenerality(ThisType);
if (ThisGenerality > CurGenerality) {
// This constraint letter is more general than the previous one,
// use it.
CurType = ThisType;
Current = &Codes[j];
CurGenerality = ThisGenerality;
}
}
ConstraintCode = *Current;
ConstraintType = CurType;
}
if (ConstraintCode == "X" && CallOperandVal) {
if (isa<BasicBlock>(CallOperandVal) || isa<ConstantInt>(CallOperandVal))
return;
// This matches anything. Labels and constants we handle elsewhere
// ('X' is the only thing that matches labels). Otherwise, try to
// resolve it to something we know about by looking at the actual
// operand type.
std::string s = "";
TLI.lowerXConstraint(ConstraintVT, s);
if (s!="") {
ConstraintCode = s;
ConstraintType = TLI.getConstraintType(ConstraintCode);
}
}
}
};
/// getConstraintType - Given a constraint, return the type of constraint it
/// is for this target.
virtual ConstraintType getConstraintType(const std::string &Constraint) const;
/// getRegClassForInlineAsmConstraint - Given a constraint letter (e.g. "r"),
/// return a list of registers that can be used to satisfy the constraint.
/// This should only be used for C_RegisterClass constraints.
virtual std::vector<unsigned>
getRegClassForInlineAsmConstraint(const std::string &Constraint,
MVT::ValueType VT) const;
/// getRegForInlineAsmConstraint - Given a physical register constraint (e.g.
/// {edx}), return the register number and the register class for the
/// register.
///
/// Given a register class constraint, like 'r', if this corresponds directly
/// to an LLVM register class, return a register of 0 and the register class
/// pointer.
///
/// This should only be used for C_Register constraints. On error,
/// this returns a register number of 0 and a null register class pointer..
virtual std::pair<unsigned, const TargetRegisterClass*>
getRegForInlineAsmConstraint(const std::string &Constraint,
MVT::ValueType VT) const;
/// LowerXConstraint - try to replace an X constraint, which matches anything,
/// with another that has more specific requirements based on the type of the
/// corresponding operand.
virtual void lowerXConstraint(MVT::ValueType ConstraintVT,
std::string&) const;
/// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
/// vector. If it is invalid, don't add anything to Ops.
virtual void LowerAsmOperandForConstraint(SDOperand Op, char ConstraintLetter,
std::vector<SDOperand> &Ops,
SelectionDAG &DAG);
//===--------------------------------------------------------------------===//
// Scheduler hooks
//
// EmitInstrWithCustomInserter - This method should be implemented by targets
// that mark instructions with the 'usesCustomDAGSchedInserter' flag. These
// instructions are special in various ways, which require special support to
// insert. The specified MachineInstr is created but not inserted into any
// basic blocks, and the scheduler passes ownership of it to this method.
virtual MachineBasicBlock *EmitInstrWithCustomInserter(MachineInstr *MI,
MachineBasicBlock *MBB);
//===--------------------------------------------------------------------===//
// Addressing mode description hooks (used by LSR etc).
//
/// AddrMode - This represents an addressing mode of:
/// BaseGV + BaseOffs + BaseReg + Scale*ScaleReg
/// If BaseGV is null, there is no BaseGV.
/// If BaseOffs is zero, there is no base offset.
/// If HasBaseReg is false, there is no base register.
/// If Scale is zero, there is no ScaleReg. Scale of 1 indicates a reg with
/// no scale.
///
struct AddrMode {
GlobalValue *BaseGV;
int64_t BaseOffs;
bool HasBaseReg;
int64_t Scale;
AddrMode() : BaseGV(0), BaseOffs(0), HasBaseReg(false), Scale(0) {}
};
/// isLegalAddressingMode - Return true if the addressing mode represented by
/// AM is legal for this target, for a load/store of the specified type.
/// TODO: Handle pre/postinc as well.
virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty) const;
/// isTruncateFree - Return true if it's free to truncate a value of
/// type Ty1 to type Ty2. e.g. On x86 it's free to truncate a i32 value in
/// register EAX to i16 by referencing its sub-register AX.
virtual bool isTruncateFree(const Type *Ty1, const Type *Ty2) const {
return false;
}
virtual bool isTruncateFree(MVT::ValueType VT1, MVT::ValueType VT2) const {
return false;
}
//===--------------------------------------------------------------------===//
// Div utility functions
//
SDOperand BuildSDIV(SDNode *N, SelectionDAG &DAG,
std::vector<SDNode*>* Created) const;
SDOperand BuildUDIV(SDNode *N, SelectionDAG &DAG,
std::vector<SDNode*>* Created) const;
//===--------------------------------------------------------------------===//
// Runtime Library hooks
//
/// setLibcallName - Rename the default libcall routine name for the specified
/// libcall.
void setLibcallName(RTLIB::Libcall Call, const char *Name) {
LibcallRoutineNames[Call] = Name;
}
/// getLibcallName - Get the libcall routine name for the specified libcall.
///
const char *getLibcallName(RTLIB::Libcall Call) const {
return LibcallRoutineNames[Call];
}
/// setCmpLibcallCC - Override the default CondCode to be used to test the
/// result of the comparison libcall against zero.
void setCmpLibcallCC(RTLIB::Libcall Call, ISD::CondCode CC) {
CmpLibcallCCs[Call] = CC;
}
/// getCmpLibcallCC - Get the CondCode that's to be used to test the result of
/// the comparison libcall against zero.
ISD::CondCode getCmpLibcallCC(RTLIB::Libcall Call) const {
return CmpLibcallCCs[Call];
}
private:
TargetMachine &TM;
const TargetData *TD;
/// IsLittleEndian - True if this is a little endian target.
///
bool IsLittleEndian;
/// PointerTy - The type to use for pointers, usually i32 or i64.
///
MVT::ValueType PointerTy;
/// UsesGlobalOffsetTable - True if this target uses a GOT for PIC codegen.
///
bool UsesGlobalOffsetTable;
/// ShiftAmountTy - The type to use for shift amounts, usually i8 or whatever
/// PointerTy is.
MVT::ValueType ShiftAmountTy;
OutOfRangeShiftAmount ShiftAmtHandling;
/// SelectIsExpensive - Tells the code generator not to expand operations
/// into sequences that use the select operations if possible.
bool SelectIsExpensive;
/// IntDivIsCheap - Tells the code generator not to expand integer divides by
/// constants into a sequence of muls, adds, and shifts. This is a hack until
/// a real cost model is in place. If we ever optimize for size, this will be
/// set to true unconditionally.
bool IntDivIsCheap;
/// Pow2DivIsCheap - Tells the code generator that it shouldn't generate
/// srl/add/sra for a signed divide by power of two, and let the target handle
/// it.
bool Pow2DivIsCheap;
/// SetCCResultTy - The type that SetCC operations use. This defaults to the
/// PointerTy.
MVT::ValueType SetCCResultTy;
/// SetCCResultContents - Information about the contents of the high-bits in
/// the result of a setcc comparison operation.
SetCCResultValue SetCCResultContents;
/// SchedPreferenceInfo - The target scheduling preference: shortest possible
/// total cycles or lowest register usage.
SchedPreference SchedPreferenceInfo;
/// UseUnderscoreSetJmp - This target prefers to use _setjmp to implement
/// llvm.setjmp. Defaults to false.
bool UseUnderscoreSetJmp;
/// UseUnderscoreLongJmp - This target prefers to use _longjmp to implement
/// llvm.longjmp. Defaults to false.
bool UseUnderscoreLongJmp;
/// JumpBufSize - The size, in bytes, of the target's jmp_buf buffers
unsigned JumpBufSize;
/// JumpBufAlignment - The alignment, in bytes, of the target's jmp_buf
/// buffers
unsigned JumpBufAlignment;
/// IfCvtBlockSizeLimit - The maximum allowed size for a block to be
/// if-converted.
unsigned IfCvtBlockSizeLimit;
/// IfCvtDupBlockSizeLimit - The maximum allowed size for a block to be
/// duplicated during if-conversion.
unsigned IfCvtDupBlockSizeLimit;
/// StackPointerRegisterToSaveRestore - If set to a physical register, this
/// specifies the register that llvm.savestack/llvm.restorestack should save
/// and restore.
unsigned StackPointerRegisterToSaveRestore;
/// ExceptionPointerRegister - If set to a physical register, this specifies
/// the register that receives the exception address on entry to a landing
/// pad.
unsigned ExceptionPointerRegister;
/// ExceptionSelectorRegister - If set to a physical register, this specifies
/// the register that receives the exception typeid on entry to a landing
/// pad.
unsigned ExceptionSelectorRegister;
/// RegClassForVT - This indicates the default register class to use for
/// each ValueType the target supports natively.
TargetRegisterClass *RegClassForVT[MVT::LAST_VALUETYPE];
unsigned char NumRegistersForVT[MVT::LAST_VALUETYPE];
MVT::ValueType RegisterTypeForVT[MVT::LAST_VALUETYPE];
/// TransformToType - For any value types we are promoting or expanding, this
/// contains the value type that we are changing to. For Expanded types, this
/// contains one step of the expand (e.g. i64 -> i32), even if there are
/// multiple steps required (e.g. i64 -> i16). For types natively supported
/// by the system, this holds the same type (e.g. i32 -> i32).
MVT::ValueType TransformToType[MVT::LAST_VALUETYPE];
/// OpActions - For each operation and each value type, keep a LegalizeAction
/// that indicates how instruction selection should deal with the operation.
/// Most operations are Legal (aka, supported natively by the target), but
/// operations that are not should be described. Note that operations on
/// non-legal value types are not described here.
uint64_t OpActions[156];
/// LoadXActions - For each load of load extension type and each value type,
/// keep a LegalizeAction that indicates how instruction selection should deal
/// with the load.
uint64_t LoadXActions[ISD::LAST_LOADX_TYPE];
/// TruncStoreActions - For each truncating store, keep a LegalizeAction that
/// indicates how instruction selection should deal with the store.
uint64_t TruncStoreActions[MVT::LAST_VALUETYPE];
/// IndexedModeActions - For each indexed mode and each value type, keep a
/// pair of LegalizeAction that indicates how instruction selection should
/// deal with the load / store.
uint64_t IndexedModeActions[2][ISD::LAST_INDEXED_MODE];
/// ConvertActions - For each conversion from source type to destination type,
/// keep a LegalizeAction that indicates how instruction selection should
/// deal with the conversion.
/// Currently, this is used only for floating->floating conversions
/// (FP_EXTEND and FP_ROUND).
uint64_t ConvertActions[MVT::LAST_VALUETYPE];
ValueTypeActionImpl ValueTypeActions;
std::vector<APFloat> LegalFPImmediates;
std::vector<std::pair<MVT::ValueType,
TargetRegisterClass*> > AvailableRegClasses;
/// TargetDAGCombineArray - Targets can specify ISD nodes that they would
/// like PerformDAGCombine callbacks for by calling setTargetDAGCombine(),
/// which sets a bit in this array.
unsigned char TargetDAGCombineArray[160/(sizeof(unsigned char)*8)];
/// PromoteToType - For operations that must be promoted to a specific type,
/// this holds the destination type. This map should be sparse, so don't hold
/// it as an array.
///
/// Targets add entries to this map with AddPromotedToType(..), clients access
/// this with getTypeToPromoteTo(..).
std::map<std::pair<unsigned, MVT::ValueType>, MVT::ValueType> PromoteToType;
/// LibcallRoutineNames - Stores the name each libcall.
///
const char *LibcallRoutineNames[RTLIB::UNKNOWN_LIBCALL];
/// CmpLibcallCCs - The ISD::CondCode that should be used to test the result
/// of each of the comparison libcall against zero.
ISD::CondCode CmpLibcallCCs[RTLIB::UNKNOWN_LIBCALL];
protected:
/// When lowering %llvm.memset this field specifies the maximum number of
/// store operations that may be substituted for the call to memset. Targets
/// must set this value based on the cost threshold for that target. Targets
/// should assume that the memset will be done using as many of the largest
/// store operations first, followed by smaller ones, if necessary, per
/// alignment restrictions. For example, storing 9 bytes on a 32-bit machine
/// with 16-bit alignment would result in four 2-byte stores and one 1-byte
/// store. This only applies to setting a constant array of a constant size.
/// @brief Specify maximum number of store instructions per memset call.
unsigned maxStoresPerMemset;
/// When lowering %llvm.memcpy this field specifies the maximum number of
/// store operations that may be substituted for a call to memcpy. Targets
/// must set this value based on the cost threshold for that target. Targets
/// should assume that the memcpy will be done using as many of the largest
/// store operations first, followed by smaller ones, if necessary, per
/// alignment restrictions. For example, storing 7 bytes on a 32-bit machine
/// with 32-bit alignment would result in one 4-byte store, a one 2-byte store
/// and one 1-byte store. This only applies to copying a constant array of
/// constant size.
/// @brief Specify maximum bytes of store instructions per memcpy call.
unsigned maxStoresPerMemcpy;
/// When lowering %llvm.memmove this field specifies the maximum number of
/// store instructions that may be substituted for a call to memmove. Targets
/// must set this value based on the cost threshold for that target. Targets
/// should assume that the memmove will be done using as many of the largest
/// store operations first, followed by smaller ones, if necessary, per
/// alignment restrictions. For example, moving 9 bytes on a 32-bit machine
/// with 8-bit alignment would result in nine 1-byte stores. This only
/// applies to copying a constant array of constant size.
/// @brief Specify maximum bytes of store instructions per memmove call.
unsigned maxStoresPerMemmove;
/// This field specifies whether the target machine permits unaligned memory
/// accesses. This is used, for example, to determine the size of store
/// operations when copying small arrays and other similar tasks.
/// @brief Indicate whether the target permits unaligned memory accesses.
bool allowUnalignedMemoryAccesses;
};
} // end llvm namespace
#endif
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