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llvm-6502/include/llvm/Target/TargetLowering.h
Evan Cheng d40d03e1bd Teach dag combine to fold the following transformation more aggressively: 
(OP (trunc x), (trunc y)) -> (trunc (OP x, y))

Unfortunately this simple change causes dag combine to infinite looping. The problem is the shrink demanded ops optimization tend to canonicalize expressions in the opposite manner. That is badness. This patch disable those optimizations in dag combine but instead it is done as a late pass in sdisel.

This also exposes some deficiencies in dag combine and x86 setcc / brcond lowering. Teach them to look pass ISD::TRUNCATE in various places.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92849 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-06 19:38:29 +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/CallingConv.h"
#include "llvm/InlineAsm.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/RuntimeLibcalls.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/DebugLoc.h"
#include "llvm/Target/TargetMachine.h"
#include <climits>
#include <map>
#include <vector>
namespace llvm {
class AllocaInst;
class CallInst;
class Function;
class FastISel;
class MachineBasicBlock;
class MachineFunction;
class MachineFrameInfo;
class MachineInstr;
class MachineModuleInfo;
class DwarfWriter;
class SDNode;
class SDValue;
class SelectionDAG;
class TargetData;
class TargetMachine;
class TargetRegisterClass;
class TargetSubtarget;
class TargetLoweringObjectFile;
class Value;
// FIXME: should this be here?
namespace TLSModel {
enum Model {
GeneralDynamic,
LocalDynamic,
InitialExec,
LocalExec
};
}
TLSModel::Model getTLSModel(const GlobalValue *GV, Reloc::Model reloc);
//===----------------------------------------------------------------------===//
/// 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 {
TargetLowering(const TargetLowering&); // DO NOT IMPLEMENT
void operator=(const TargetLowering&); // DO NOT IMPLEMENT
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 BooleanContent { // How the target represents true/false values.
UndefinedBooleanContent, // Only bit 0 counts, the rest can hold garbage.
ZeroOrOneBooleanContent, // All bits zero except for bit 0.
ZeroOrNegativeOneBooleanContent // All bits equal to bit 0.
};
enum SchedPreference {
SchedulingForLatency, // Scheduling for shortest total latency.
SchedulingForRegPressure // Scheduling for lowest register pressure.
};
/// NOTE: The constructor takes ownership of TLOF.
explicit TargetLowering(TargetMachine &TM, TargetLoweringObjectFile *TLOF);
virtual ~TargetLowering();
TargetMachine &getTargetMachine() const { return TM; }
const TargetData *getTargetData() const { return TD; }
TargetLoweringObjectFile &getObjFileLowering() const { return TLOF; }
bool isBigEndian() const { return !IsLittleEndian; }
bool isLittleEndian() const { return IsLittleEndian; }
MVT getPointerTy() const { return PointerTy; }
MVT getShiftAmountTy() const { return ShiftAmountTy; }
/// 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; }
/// getSetCCResultType - Return the ValueType of the result of SETCC
/// operations. Also used to obtain the target's preferred type for
/// the condition operand of SELECT and BRCOND nodes. In the case of
/// BRCOND the argument passed is MVT::Other since there are no other
/// operands to get a type hint from.
virtual
MVT::SimpleValueType getSetCCResultType(EVT VT) const;
/// getCmpLibcallReturnType - Return the ValueType for comparison
/// libcalls. Comparions libcalls include floating point comparion calls,
/// and Ordered/Unordered check calls on floating point numbers.
virtual
MVT::SimpleValueType getCmpLibcallReturnType() const;
/// getBooleanContents - For targets without i1 registers, this gives the
/// nature of the high-bits of boolean values held in types wider than i1.
/// "Boolean values" are special true/false values produced by nodes like
/// SETCC and consumed (as the condition) by nodes like SELECT and BRCOND.
/// Not to be confused with general values promoted from i1.
BooleanContent getBooleanContents() const { return BooleanContents;}
/// 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(EVT VT) const {
assert(VT.isSimple() && "getRegClassFor called on illegal type!");
TargetRegisterClass *RC = RegClassForVT[VT.getSimpleVT().SimpleTy];
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(EVT VT) const {
assert(!VT.isSimple() ||
(unsigned)VT.getSimpleVT().SimpleTy < array_lengthof(RegClassForVT));
return VT.isSimple() && RegClassForVT[VT.getSimpleVT().SimpleTy] != 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)".
/// dimension by (MVT::MAX_ALLOWED_VALUETYPE/32) * 2
uint32_t ValueTypeActions[(MVT::MAX_ALLOWED_VALUETYPE/32)*2];
public:
ValueTypeActionImpl() {
ValueTypeActions[0] = ValueTypeActions[1] = 0;
ValueTypeActions[2] = ValueTypeActions[3] = 0;
}
ValueTypeActionImpl(const ValueTypeActionImpl &RHS) {
ValueTypeActions[0] = RHS.ValueTypeActions[0];
ValueTypeActions[1] = RHS.ValueTypeActions[1];
ValueTypeActions[2] = RHS.ValueTypeActions[2];
ValueTypeActions[3] = RHS.ValueTypeActions[3];
}
LegalizeAction getTypeAction(LLVMContext &Context, EVT VT) const {
if (VT.isExtended()) {
if (VT.isVector()) {
return VT.isPow2VectorType() ? Expand : Promote;
}
if (VT.isInteger())
// First promote to a power-of-two size, then expand if necessary.
return VT == VT.getRoundIntegerType(Context) ? Expand : Promote;
assert(0 && "Unsupported extended type!");
return Legal;
}
unsigned I = VT.getSimpleVT().SimpleTy;
assert(I<4*array_lengthof(ValueTypeActions)*sizeof(ValueTypeActions[0]));
return (LegalizeAction)((ValueTypeActions[I>>4] >> ((2*I) & 31)) & 3);
}
void setTypeAction(EVT VT, LegalizeAction Action) {
unsigned I = VT.getSimpleVT().SimpleTy;
assert(I<4*array_lengthof(ValueTypeActions)*sizeof(ValueTypeActions[0]));
ValueTypeActions[I>>4] |= Action << ((I*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(LLVMContext &Context, EVT VT) const {
return ValueTypeActions.getTypeAction(Context, 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.
EVT getTypeToTransformTo(LLVMContext &Context, EVT VT) const {
if (VT.isSimple()) {
assert((unsigned)VT.getSimpleVT().SimpleTy <
array_lengthof(TransformToType));
EVT NVT = TransformToType[VT.getSimpleVT().SimpleTy];
assert(getTypeAction(Context, NVT) != Promote &&
"Promote may not follow Expand or Promote");
return NVT;
}
if (VT.isVector()) {
EVT NVT = VT.getPow2VectorType(Context);
if (NVT == VT) {
// Vector length is a power of 2 - split to half the size.
unsigned NumElts = VT.getVectorNumElements();
EVT EltVT = VT.getVectorElementType();
return (NumElts == 1) ?
EltVT : EVT::getVectorVT(Context, EltVT, NumElts / 2);
}
// Promote to a power of two size, avoiding multi-step promotion.
return getTypeAction(Context, NVT) == Promote ?
getTypeToTransformTo(Context, NVT) : NVT;
} else if (VT.isInteger()) {
EVT NVT = VT.getRoundIntegerType(Context);
if (NVT == VT)
// Size is a power of two - expand to half the size.
return EVT::getIntegerVT(Context, VT.getSizeInBits() / 2);
else
// Promote to a power of two size, avoiding multi-step promotion.
return getTypeAction(Context, NVT) == Promote ?
getTypeToTransformTo(Context, NVT) : NVT;
}
assert(0 && "Unsupported extended type!");
return MVT(MVT::Other); // Not reached
}
/// 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.
EVT getTypeToExpandTo(LLVMContext &Context, EVT VT) const {
assert(!VT.isVector());
while (true) {
switch (getTypeAction(Context, VT)) {
case Legal:
return VT;
case Expand:
VT = getTypeToTransformTo(Context, 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, EVT::v8f32 maps to 2 EVT::v4f32
/// with Altivec or SSE1, or 8 promoted EVT::f64 values with the X86 FP stack.
/// Similarly, EVT::v2i64 turns into 4 EVT::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(LLVMContext &Context, EVT VT,
EVT &IntermediateVT,
unsigned &NumIntermediates,
EVT &RegisterVT) const;
/// getTgtMemIntrinsic: Given an intrinsic, checks if on the target the
/// intrinsic will need to map to a MemIntrinsicNode (touches memory). If
/// this is the case, it returns true and store the intrinsic
/// information into the IntrinsicInfo that was passed to the function.
typedef struct IntrinsicInfo {
unsigned opc; // target opcode
EVT memVT; // memory VT
const Value* ptrVal; // value representing memory location
int offset; // offset off of ptrVal
unsigned align; // alignment
bool vol; // is volatile?
bool readMem; // reads memory?
bool writeMem; // writes memory?
} IntrinisicInfo;
virtual bool getTgtMemIntrinsic(IntrinsicInfo& Info,
CallInst &I, unsigned Intrinsic) {
return false;
}
/// getWidenVectorType: given a vector type, returns the type to widen to
/// (e.g., v7i8 to v8i8). If the vector type is legal, it returns itself.
/// If there is no vector type that we want to widen to, returns MVT::Other
/// When and were to widen is target dependent based on the cost of
/// scalarizing vs using the wider vector type.
virtual EVT getWidenVectorType(EVT VT) const;
/// isFPImmLegal - Returns true if the target can instruction select the
/// specified FP immediate natively. If false, the legalizer will materialize
/// the FP immediate as a load from a constant pool.
virtual bool isFPImmLegal(const APFloat &Imm, EVT VT) const {
return false;
}
/// 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(const SmallVectorImpl<int> &Mask,
EVT 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(const SmallVectorImpl<int> &Mask,
EVT VT) 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, EVT VT) const {
if (VT.isExtended()) return Expand;
assert(Op < array_lengthof(OpActions[0]) &&
(unsigned)VT.getSimpleVT().SimpleTy < sizeof(OpActions[0][0])*8 &&
"Table isn't big enough!");
unsigned I = (unsigned) VT.getSimpleVT().SimpleTy;
unsigned J = I & 31;
I = I >> 5;
return (LegalizeAction)((OpActions[I][Op] >> (J*2) ) & 3);
}
/// isOperationLegalOrCustom - Return true if the specified operation is
/// legal on this target or can be made legal with custom lowering. This
/// is used to help guide high-level lowering decisions.
bool isOperationLegalOrCustom(unsigned Op, EVT VT) const {
return (VT == MVT::Other || isTypeLegal(VT)) &&
(getOperationAction(Op, VT) == Legal ||
getOperationAction(Op, VT) == Custom);
}
/// isOperationLegal - Return true if the specified operation is legal on this
/// target.
bool isOperationLegal(unsigned Op, EVT VT) const {
return (VT == MVT::Other || isTypeLegal(VT)) &&
getOperationAction(Op, VT) == Legal;
}
/// getLoadExtAction - 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 getLoadExtAction(unsigned LType, EVT VT) const {
assert(LType < array_lengthof(LoadExtActions) &&
(unsigned)VT.getSimpleVT().SimpleTy < sizeof(LoadExtActions[0])*4 &&
"Table isn't big enough!");
return (LegalizeAction)((LoadExtActions[LType] >>
(2*VT.getSimpleVT().SimpleTy)) & 3);
}
/// isLoadExtLegal - Return true if the specified load with extension is legal
/// on this target.
bool isLoadExtLegal(unsigned LType, EVT VT) const {
return VT.isSimple() &&
(getLoadExtAction(LType, VT) == Legal ||
getLoadExtAction(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(EVT ValVT,
EVT MemVT) const {
assert((unsigned)ValVT.getSimpleVT().SimpleTy <
array_lengthof(TruncStoreActions) &&
(unsigned)MemVT.getSimpleVT().SimpleTy <
sizeof(TruncStoreActions[0])*4 &&
"Table isn't big enough!");
return (LegalizeAction)((TruncStoreActions[ValVT.getSimpleVT().SimpleTy] >>
(2*MemVT.getSimpleVT().SimpleTy)) & 3);
}
/// isTruncStoreLegal - Return true if the specified store with truncation is
/// legal on this target.
bool isTruncStoreLegal(EVT ValVT, EVT MemVT) const {
return isTypeLegal(ValVT) && MemVT.isSimple() &&
(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, EVT VT) const {
assert( IdxMode < array_lengthof(IndexedModeActions[0][0]) &&
((unsigned)VT.getSimpleVT().SimpleTy) < MVT::LAST_VALUETYPE &&
"Table isn't big enough!");
return (LegalizeAction)((IndexedModeActions[
(unsigned)VT.getSimpleVT().SimpleTy][0][IdxMode]));
}
/// isIndexedLoadLegal - Return true if the specified indexed load is legal
/// on this target.
bool isIndexedLoadLegal(unsigned IdxMode, EVT VT) const {
return VT.isSimple() &&
(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, EVT VT) const {
assert(IdxMode < array_lengthof(IndexedModeActions[0][1]) &&
(unsigned)VT.getSimpleVT().SimpleTy < MVT::LAST_VALUETYPE &&
"Table isn't big enough!");
return (LegalizeAction)((IndexedModeActions[
(unsigned)VT.getSimpleVT().SimpleTy][1][IdxMode]));
}
/// isIndexedStoreLegal - Return true if the specified indexed load is legal
/// on this target.
bool isIndexedStoreLegal(unsigned IdxMode, EVT VT) const {
return VT.isSimple() &&
(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(EVT FromVT, EVT ToVT) const {
assert((unsigned)FromVT.getSimpleVT().SimpleTy <
array_lengthof(ConvertActions) &&
(unsigned)ToVT.getSimpleVT().SimpleTy <
sizeof(ConvertActions[0])*4 &&
"Table isn't big enough!");
return (LegalizeAction)((ConvertActions[FromVT.getSimpleVT().SimpleTy] >>
(2*ToVT.getSimpleVT().SimpleTy)) & 3);
}
/// isConvertLegal - Return true if the specified conversion is legal
/// on this target.
bool isConvertLegal(EVT FromVT, EVT ToVT) const {
return isTypeLegal(FromVT) && isTypeLegal(ToVT) &&
(getConvertAction(FromVT, ToVT) == Legal ||
getConvertAction(FromVT, ToVT) == Custom);
}
/// getCondCodeAction - Return how the condition code should be treated:
/// either it is legal, needs to be expanded to some other code sequence,
/// or the target has a custom expander for it.
LegalizeAction
getCondCodeAction(ISD::CondCode CC, EVT VT) const {
assert((unsigned)CC < array_lengthof(CondCodeActions) &&
(unsigned)VT.getSimpleVT().SimpleTy < sizeof(CondCodeActions[0])*4 &&
"Table isn't big enough!");
LegalizeAction Action = (LegalizeAction)
((CondCodeActions[CC] >> (2*VT.getSimpleVT().SimpleTy)) & 3);
assert(Action != Promote && "Can't promote condition code!");
return Action;
}
/// isCondCodeLegal - Return true if the specified condition code is legal
/// on this target.
bool isCondCodeLegal(ISD::CondCode CC, EVT VT) const {
return getCondCodeAction(CC, VT) == Legal ||
getCondCodeAction(CC, VT) == Custom;
}
/// getTypeToPromoteTo - If the action for this operation is to promote, this
/// method returns the ValueType to promote to.
EVT getTypeToPromoteTo(unsigned Op, EVT 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::SimpleValueType>,
MVT::SimpleValueType>::const_iterator PTTI =
PromoteToType.find(std::make_pair(Op, VT.getSimpleVT().SimpleTy));
if (PTTI != PromoteToType.end()) return PTTI->second;
assert((VT.isInteger() || VT.isFloatingPoint()) &&
"Cannot autopromote this type, add it with AddPromotedToType.");
EVT NVT = VT;
do {
NVT = (MVT::SimpleValueType)(NVT.getSimpleVT().SimpleTy+1);
assert(NVT.isInteger() == VT.isInteger() && NVT != MVT::isVoid &&
"Didn't find type to promote to!");
} while (!isTypeLegal(NVT) ||
getOperationAction(Op, NVT) == Promote);
return NVT;
}
/// getValueType - Return the EVT 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 EVT
/// counterpart (e.g. structs), otherwise it will assert.
EVT getValueType(const Type *Ty, bool AllowUnknown = false) const {
EVT VT = EVT::getEVT(Ty, AllowUnknown);
return VT == MVT:: iPTR ? PointerTy : VT;
}
/// getByValTypeAlignment - Return the desired alignment for ByVal aggregate
/// function arguments in the caller parameter area. This is the actual
/// alignment, not its logarithm.
virtual unsigned getByValTypeAlignment(const Type *Ty) const;
/// getRegisterType - Return the type of registers that this ValueType will
/// eventually require.
EVT getRegisterType(MVT VT) const {
assert((unsigned)VT.SimpleTy < array_lengthof(RegisterTypeForVT));
return RegisterTypeForVT[VT.SimpleTy];
}
/// getRegisterType - Return the type of registers that this ValueType will
/// eventually require.
EVT getRegisterType(LLVMContext &Context, EVT VT) const {
if (VT.isSimple()) {
assert((unsigned)VT.getSimpleVT().SimpleTy <
array_lengthof(RegisterTypeForVT));
return RegisterTypeForVT[VT.getSimpleVT().SimpleTy];
}
if (VT.isVector()) {
EVT VT1, RegisterVT;
unsigned NumIntermediates;
(void)getVectorTypeBreakdown(Context, VT, VT1,
NumIntermediates, RegisterVT);
return RegisterVT;
}
if (VT.isInteger()) {
return getRegisterType(Context, getTypeToTransformTo(Context, VT));
}
assert(0 && "Unsupported extended type!");
return EVT(MVT::Other); // Not reached
}
/// 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(LLVMContext &Context, EVT VT) const {
if (VT.isSimple()) {
assert((unsigned)VT.getSimpleVT().SimpleTy <
array_lengthof(NumRegistersForVT));
return NumRegistersForVT[VT.getSimpleVT().SimpleTy];
}
if (VT.isVector()) {
EVT VT1, VT2;
unsigned NumIntermediates;
return getVectorTypeBreakdown(Context, VT, VT1, NumIntermediates, VT2);
}
if (VT.isInteger()) {
unsigned BitWidth = VT.getSizeInBits();
unsigned RegWidth = getRegisterType(Context, VT).getSizeInBits();
return (BitWidth + RegWidth - 1) / RegWidth;
}
assert(0 && "Unsupported extended type!");
return 0; // Not reached
}
/// ShouldShrinkFPConstant - If true, then instruction selection should
/// seek to shrink the FP constant of the specified type to a smaller type
/// in order to save space and / or reduce runtime.
virtual bool ShouldShrinkFPConstant(EVT VT) const { return true; }
/// 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.
/// of the specified type. 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.
virtual bool allowsUnalignedMemoryAccesses(EVT VT) const {
return false;
}
/// This function returns true if the target would benefit from code placement
/// optimization.
/// @brief Determine if the target should perform code placement optimization.
bool shouldOptimizeCodePlacement() const {
return benefitFromCodePlacementOpt;
}
/// getOptimalMemOpType - Returns the target specific optimal type for load
/// and store operations as a result of memset, memcpy, and memmove lowering.
/// It returns EVT::iAny if SelectionDAG should be responsible for
/// determining it.
virtual EVT getOptimalMemOpType(uint64_t Size, unsigned Align,
bool isSrcConst, bool isSrcStr,
SelectionDAG &DAG) const {
return MVT::iAny;
}
/// 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.
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.
unsigned getIfCvtDupBlockSizeLimit() const {
return IfCvtDupBlockSizeLimit;
}
/// getPrefLoopAlignment - return the preferred loop alignment.
///
unsigned getPrefLoopAlignment() const {
return PrefLoopAlignment;
}
/// 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, SDValue &Base,
SDValue &Offset,
ISD::MemIndexedMode &AM,
SelectionDAG &DAG) const {
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,
SDValue &Base, SDValue &Offset,
ISD::MemIndexedMode &AM,
SelectionDAG &DAG) const {
return false;
}
/// getPICJumpTableRelocaBase - Returns relocation base for the given PIC
/// jumptable.
virtual SDValue getPICJumpTableRelocBase(SDValue Table,
SelectionDAG &DAG) const;
/// isOffsetFoldingLegal - Return true if folding a constant offset
/// with the given GlobalAddress is legal. It is frequently not legal in
/// PIC relocation models.
virtual bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const;
/// getFunctionAlignment - Return the Log2 alignment of this function.
virtual unsigned getFunctionAlignment(const Function *) const = 0;
//===--------------------------------------------------------------------===//
// TargetLowering Optimization Methods
//
/// TargetLoweringOpt - A convenience struct that encapsulates a DAG, and two
/// SDValues for returning information from TargetLowering to its clients
/// that want to combine
struct TargetLoweringOpt {
SelectionDAG &DAG;
bool ShrinkOps;
SDValue Old;
SDValue New;
explicit TargetLoweringOpt(SelectionDAG &InDAG, bool Shrink = false) :
DAG(InDAG), ShrinkOps(Shrink) {}
bool CombineTo(SDValue O, SDValue 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(SDValue Op, const APInt &Demanded);
/// ShrinkDemandedOp - Convert x+y to (VT)((SmallVT)x+(SmallVT)y) if the
/// casts are free. This uses isZExtFree and ZERO_EXTEND for the widening
/// cast, but it could be generalized for targets with other types of
/// implicit widening casts.
bool ShrinkDemandedOp(SDValue Op, unsigned BitWidth, const APInt &Demanded,
DebugLoc dl);
};
/// 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(SDValue 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 SDValue 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(SDValue Op,
unsigned Depth = 0) const;
struct DAGCombinerInfo {
void *DC; // The DAG Combiner object.
bool BeforeLegalize;
bool BeforeLegalizeOps;
bool CalledByLegalizer;
public:
SelectionDAG &DAG;
DAGCombinerInfo(SelectionDAG &dag, bool bl, bool blo, bool cl, void *dc)
: DC(dc), BeforeLegalize(bl), BeforeLegalizeOps(blo),
CalledByLegalizer(cl), DAG(dag) {}
bool isBeforeLegalize() const { return BeforeLegalize; }
bool isBeforeLegalizeOps() const { return BeforeLegalizeOps; }
bool isCalledByLegalizer() const { return CalledByLegalizer; }
void AddToWorklist(SDNode *N);
SDValue CombineTo(SDNode *N, const std::vector<SDValue> &To,
bool AddTo = true);
SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true);
SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo = true);
void CommitTargetLoweringOpt(const TargetLoweringOpt &TLO);
};
/// SimplifySetCC - Try to simplify a setcc built with the specified operands
/// and cc. If it is unable to simplify it, return a null SDValue.
SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
ISD::CondCode Cond, bool foldBooleans,
DAGCombinerInfo &DCI, DebugLoc dl) const;
/// isGAPlusOffset - Returns true (and the GlobalValue and the offset) if the
/// node is a GlobalAddress + offset.
virtual bool
isGAPlusOffset(SDNode *N, GlobalValue* &GA, int64_t &Offset) 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:
/// SDValue.Val == 0 - No change was made
/// SDValue.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 SDValue 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 VT) { ShiftAmountTy = VT; }
/// setBooleanContents - Specify how the target extends the result of a
/// boolean value from i1 to a wider type. See getBooleanContents.
void setBooleanContents(BooleanContent Ty) { BooleanContents = Ty; }
/// setSchedulingPreference - Specify the target scheduling preference.
void setSchedulingPreference(SchedPreference Pref) {
SchedPreferenceInfo = Pref;
}
/// 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(EVT VT, TargetRegisterClass *RC) {
assert((unsigned)VT.getSimpleVT().SimpleTy < array_lengthof(RegClassForVT));
AvailableRegClasses.push_back(std::make_pair(VT, RC));
RegClassForVT[VT.getSimpleVT().SimpleTy] = 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 VT,
LegalizeAction Action) {
unsigned I = (unsigned)VT.SimpleTy;
unsigned J = I & 31;
I = I >> 5;
OpActions[I][Op] &= ~(uint64_t(3UL) << (J*2));
OpActions[I][Op] |= (uint64_t)Action << (J*2);
}
/// setLoadExtAction - Indicate that the specified load with extension does
/// not work with the with specified type and indicate what to do about it.
void setLoadExtAction(unsigned ExtType, MVT VT,
LegalizeAction Action) {
assert((unsigned)VT.SimpleTy*2 < 63 &&
ExtType < array_lengthof(LoadExtActions) &&
"Table isn't big enough!");
LoadExtActions[ExtType] &= ~(uint64_t(3UL) << VT.SimpleTy*2);
LoadExtActions[ExtType] |= (uint64_t)Action << VT.SimpleTy*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 ValVT, MVT MemVT,
LegalizeAction Action) {
assert((unsigned)ValVT.SimpleTy < array_lengthof(TruncStoreActions) &&
(unsigned)MemVT.SimpleTy*2 < 63 &&
"Table isn't big enough!");
TruncStoreActions[ValVT.SimpleTy] &= ~(uint64_t(3UL) << MemVT.SimpleTy*2);
TruncStoreActions[ValVT.SimpleTy] |= (uint64_t)Action << MemVT.SimpleTy*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 VT,
LegalizeAction Action) {
assert((unsigned)VT.SimpleTy < MVT::LAST_VALUETYPE &&
IdxMode < array_lengthof(IndexedModeActions[0][0]) &&
"Table isn't big enough!");
IndexedModeActions[(unsigned)VT.SimpleTy][0][IdxMode] = (uint8_t)Action;
}
/// 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 VT,
LegalizeAction Action) {
assert((unsigned)VT.SimpleTy < MVT::LAST_VALUETYPE &&
IdxMode < array_lengthof(IndexedModeActions[0][1] ) &&
"Table isn't big enough!");
IndexedModeActions[(unsigned)VT.SimpleTy][1][IdxMode] = (uint8_t)Action;
}
/// 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 FromVT, MVT ToVT,
LegalizeAction Action) {
assert((unsigned)FromVT.SimpleTy < array_lengthof(ConvertActions) &&
(unsigned)ToVT.SimpleTy < MVT::LAST_VALUETYPE &&
"Table isn't big enough!");
ConvertActions[FromVT.SimpleTy] &= ~(uint64_t(3UL) << ToVT.SimpleTy*2);
ConvertActions[FromVT.SimpleTy] |= (uint64_t)Action << ToVT.SimpleTy*2;
}
/// setCondCodeAction - Indicate that the specified condition code is or isn't
/// supported on the target and indicate what to do about it.
void setCondCodeAction(ISD::CondCode CC, MVT VT,
LegalizeAction Action) {
assert((unsigned)VT.SimpleTy < MVT::LAST_VALUETYPE &&
(unsigned)CC < array_lengthof(CondCodeActions) &&
"Table isn't big enough!");
CondCodeActions[(unsigned)CC] &= ~(uint64_t(3UL) << VT.SimpleTy*2);
CondCodeActions[(unsigned)CC] |= (uint64_t)Action << VT.SimpleTy*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 OrigVT, MVT DestVT) {
PromoteToType[std::make_pair(Opc, OrigVT.SimpleTy)] = DestVT.SimpleTy;
}
/// 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;
}
/// setPrefLoopAlignment - Set the target's preferred loop alignment. Default
/// alignment is zero, it means the target does not care about loop alignment.
void setPrefLoopAlignment(unsigned Align) {
PrefLoopAlignment = Align;
}
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.
//
/// LowerFormalArguments - This hook must be implemented to lower the
/// incoming (formal) arguments, described by the Ins array, into the
/// specified DAG. The implementation should fill in the InVals array
/// with legal-type argument values, and return the resulting token
/// chain value.
///
virtual SDValue
LowerFormalArguments(SDValue Chain,
CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) {
assert(0 && "Not Implemented");
return SDValue(); // this is here to silence compiler errors
}
/// LowerCallTo - This function 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. It calls LowerCall to do the actual
/// lowering.
struct ArgListEntry {
SDValue Node;
const Type* Ty;
bool isSExt : 1;
bool isZExt : 1;
bool isInReg : 1;
bool isSRet : 1;
bool isNest : 1;
bool isByVal : 1;
uint16_t Alignment;
ArgListEntry() : isSExt(false), isZExt(false), isInReg(false),
isSRet(false), isNest(false), isByVal(false), Alignment(0) { }
};
typedef std::vector<ArgListEntry> ArgListTy;
std::pair<SDValue, SDValue>
LowerCallTo(SDValue Chain, const Type *RetTy, bool RetSExt, bool RetZExt,
bool isVarArg, bool isInreg, unsigned NumFixedArgs,
CallingConv::ID CallConv, bool isTailCall,
bool isReturnValueUsed, SDValue Callee, ArgListTy &Args,
SelectionDAG &DAG, DebugLoc dl, unsigned Order);
/// LowerCall - This hook must be implemented to lower calls into the
/// the specified DAG. The outgoing arguments to the call are described
/// by the Outs array, and the values to be returned by the call are
/// described by the Ins array. The implementation should fill in the
/// InVals array with legal-type return values from the call, and return
/// the resulting token chain value.
///
/// The isTailCall flag here is normative. If it is true, the
/// implementation must emit a tail call. The
/// IsEligibleForTailCallOptimization hook should be used to catch
/// cases that cannot be handled.
///
virtual SDValue
LowerCall(SDValue Chain, SDValue Callee,
CallingConv::ID CallConv, bool isVarArg, bool isTailCall,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<ISD::InputArg> &Ins,
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) {
assert(0 && "Not Implemented");
return SDValue(); // this is here to silence compiler errors
}
/// CanLowerReturn - This hook should be implemented to check whether the
/// return values described by the Outs array can fit into the return
/// registers. If false is returned, an sret-demotion is performed.
///
virtual bool CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<EVT> &OutTys,
const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
SelectionDAG &DAG)
{
// Return true by default to get preexisting behavior.
return true;
}
/// LowerReturn - This hook must be implemented to lower outgoing
/// return values, described by the Outs array, into the specified
/// DAG. The implementation should return the resulting token chain
/// value.
///
virtual SDValue
LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
DebugLoc dl, SelectionDAG &DAG) {
assert(0 && "Not Implemented");
return SDValue(); // this is here to silence compiler errors
}
/// EmitTargetCodeForMemcpy - Emit target-specific code that performs a
/// memcpy. This can be used by targets to provide code sequences for cases
/// that don't fit the target's parameters for simple loads/stores and can be
/// more efficient than using a library call. This function can return a null
/// SDValue if the target declines to use custom code and a different
/// lowering strategy should be used.
///
/// If AlwaysInline is true, the size is constant and the target should not
/// emit any calls and is strongly encouraged to attempt to emit inline code
/// even if it is beyond the usual threshold because this intrinsic is being
/// expanded in a place where calls are not feasible (e.g. within the prologue
/// for another call). If the target chooses to decline an AlwaysInline
/// request here, legalize will resort to using simple loads and stores.
virtual SDValue
EmitTargetCodeForMemcpy(SelectionDAG &DAG, DebugLoc dl,
SDValue Chain,
SDValue Op1, SDValue Op2,
SDValue Op3, unsigned Align,
bool AlwaysInline,
const Value *DstSV, uint64_t DstOff,
const Value *SrcSV, uint64_t SrcOff) {
return SDValue();
}
/// EmitTargetCodeForMemmove - Emit target-specific code that performs a
/// memmove. This can be used by targets to provide code sequences for cases
/// that don't fit the target's parameters for simple loads/stores and can be
/// more efficient than using a library call. This function can return a null
/// SDValue if the target declines to use custom code and a different
/// lowering strategy should be used.
virtual SDValue
EmitTargetCodeForMemmove(SelectionDAG &DAG, DebugLoc dl,
SDValue Chain,
SDValue Op1, SDValue Op2,
SDValue Op3, unsigned Align,
const Value *DstSV, uint64_t DstOff,
const Value *SrcSV, uint64_t SrcOff) {
return SDValue();
}
/// EmitTargetCodeForMemset - Emit target-specific code that performs a
/// memset. This can be used by targets to provide code sequences for cases
/// that don't fit the target's parameters for simple stores and can be more
/// efficient than using a library call. This function can return a null
/// SDValue if the target declines to use custom code and a different
/// lowering strategy should be used.
virtual SDValue
EmitTargetCodeForMemset(SelectionDAG &DAG, DebugLoc dl,
SDValue Chain,
SDValue Op1, SDValue Op2,
SDValue Op3, unsigned Align,
const Value *DstSV, uint64_t DstOff) {
return SDValue();
}
/// LowerOperationWrapper - This callback is invoked by the type legalizer
/// to legalize nodes with an illegal operand type but legal result types.
/// It replaces the LowerOperation callback in the type Legalizer.
/// The reason we can not do away with LowerOperation entirely is that
/// LegalizeDAG isn't yet ready to use this callback.
/// TODO: Consider merging with ReplaceNodeResults.
/// The target places new result values for the node in Results (their number
/// and types must exactly match those of the original return values of
/// the node), or leaves Results empty, which indicates that the node is not
/// to be custom lowered after all.
/// The default implementation calls LowerOperation.
virtual void LowerOperationWrapper(SDNode *N,
SmallVectorImpl<SDValue> &Results,
SelectionDAG &DAG);
/// 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 SDValue LowerOperation(SDValue Op, SelectionDAG &DAG);
/// ReplaceNodeResults - This callback is invoked when a node result type is
/// illegal for the target, and the operation was registered to use 'custom'
/// lowering for that result type. The target places new result values for
/// the node in Results (their number and types must exactly match those of
/// the original return values of the node), or leaves Results empty, which
/// indicates that the node is not to be custom lowered after all.
///
/// If the target has no operations that require custom lowering, it need not
/// implement this. The default implementation aborts.
virtual void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results,
SelectionDAG &DAG) {
assert(0 && "ReplaceNodeResults not implemented for this target!");
}
/// 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(SDValue Callee,
CallingConv::ID CalleeCC,
bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
SelectionDAG& DAG) const {
// Conservative default: no calls are eligible.
return false;
}
/// getTargetNodeName() - This method returns the name of a target specific
/// DAG node.
virtual const char *getTargetNodeName(unsigned Opcode) const;
/// createFastISel - This method returns a target specific FastISel object,
/// or null if the target does not support "fast" ISel.
virtual FastISel *
createFastISel(MachineFunction &,
MachineModuleInfo *, DwarfWriter *,
DenseMap<const Value *, unsigned> &,
DenseMap<const BasicBlock *, MachineBasicBlock *> &,
DenseMap<const AllocaInst *, int> &
#ifndef NDEBUG
, SmallSet<Instruction*, 8> &CatchInfoLost
#endif
) {
return 0;
}
//===--------------------------------------------------------------------===//
// Inline Asm Support hooks
//
/// ExpandInlineAsm - This hook allows the target to expand an inline asm
/// call to be explicit llvm code if it wants to. This is useful for
/// turning simple inline asms into LLVM intrinsics, which gives the
/// compiler more information about the behavior of the code.
virtual bool ExpandInlineAsm(CallInst *CI) const {
return false;
}
enum ConstraintType {
C_Register, // Constraint represents specific register(s).
C_RegisterClass, // Constraint represents any of register(s) in class.
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".
/// TargetLowering picks the 'best' code from ConstraintInfo::Codes that
/// most closely matches the operand.
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.
EVT ConstraintVT;
/// isMatchingInputConstraint - Return true of this is an input operand that
/// is a matching constraint like "4".
bool isMatchingInputConstraint() const;
/// getMatchedOperand - If this is an input matching constraint, this method
/// returns the output operand it matches.
unsigned getMatchedOperand() const;
AsmOperandInfo(const InlineAsm::ConstraintInfo &info)
: InlineAsm::ConstraintInfo(info),
ConstraintType(TargetLowering::C_Unknown),
CallOperandVal(0), ConstraintVT(MVT::Other) {
}
};
/// ComputeConstraintToUse - Determines the constraint code and constraint
/// type to use for the specific AsmOperandInfo, setting
/// OpInfo.ConstraintCode and OpInfo.ConstraintType. If the actual operand
/// being passed in is available, it can be passed in as Op, otherwise an
/// empty SDValue can be passed. If hasMemory is true it means one of the asm
/// constraint of the inline asm instruction being processed is 'm'.
virtual void ComputeConstraintToUse(AsmOperandInfo &OpInfo,
SDValue Op,
bool hasMemory,
SelectionDAG *DAG = 0) const;
/// 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,
EVT 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,
EVT 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. This returns null if there is no replacement to
/// make.
virtual const char *LowerXConstraint(EVT ConstraintVT) const;
/// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
/// vector. If it is invalid, don't add anything to Ops. If hasMemory is true
/// it means one of the asm constraint of the inline asm instruction being
/// processed is 'm'.
virtual void LowerAsmOperandForConstraint(SDValue Op, char ConstraintLetter,
bool hasMemory,
std::vector<SDValue> &Ops,
SelectionDAG &DAG) const;
//===--------------------------------------------------------------------===//
// Instruction Emitting Hooks
//
// EmitInstrWithCustomInserter - This method should be implemented by targets
// that mark instructions with the 'usesCustomInserter' 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 this method is called to expand it into a sequence of
// instructions, potentially also creating new basic blocks and control flow.
// When new basic blocks are inserted and the edges from MBB to its successors
// are modified, the method should insert pairs of <OldSucc, NewSucc> into the
// DenseMap.
virtual MachineBasicBlock *EmitInstrWithCustomInserter(MachineInstr *MI,
MachineBasicBlock *MBB,
DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) const;
//===--------------------------------------------------------------------===//
// 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.
/// The type may be VoidTy, in which case only return true if the addressing
/// mode is legal for a load/store of any legal 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(EVT VT1, EVT VT2) const {
return false;
}
/// isZExtFree - Return true if any actual instruction that defines a
/// value of type Ty1 implicitly zero-extends the value to Ty2 in the result
/// register. This does not necessarily include registers defined in
/// unknown ways, such as incoming arguments, or copies from unknown
/// virtual registers. Also, if isTruncateFree(Ty2, Ty1) is true, this
/// does not necessarily apply to truncate instructions. e.g. on x86-64,
/// all instructions that define 32-bit values implicit zero-extend the
/// result out to 64 bits.
virtual bool isZExtFree(const Type *Ty1, const Type *Ty2) const {
return false;
}
virtual bool isZExtFree(EVT VT1, EVT VT2) const {
return false;
}
/// isNarrowingProfitable - Return true if it's profitable to narrow
/// operations of type VT1 to VT2. e.g. on x86, it's profitable to narrow
/// from i32 to i8 but not from i32 to i16.
virtual bool isNarrowingProfitable(EVT VT1, EVT VT2) const {
return false;
}
/// isLegalICmpImmediate - Return true if the specified immediate is legal
/// icmp immediate, that is the target has icmp instructions which can compare
/// a register against the immediate without having to materialize the
/// immediate into a register.
virtual bool isLegalICmpImmediate(int64_t Imm) const {
return true;
}
//===--------------------------------------------------------------------===//
// Div utility functions
//
SDValue BuildSDIV(SDNode *N, SelectionDAG &DAG,
std::vector<SDNode*>* Created) const;
SDValue 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];
}
/// setLibcallCallingConv - Set the CallingConv that should be used for the
/// specified libcall.
void setLibcallCallingConv(RTLIB::Libcall Call, CallingConv::ID CC) {
LibcallCallingConvs[Call] = CC;
}
/// getLibcallCallingConv - Get the CallingConv that should be used for the
/// specified libcall.
CallingConv::ID getLibcallCallingConv(RTLIB::Libcall Call) const {
return LibcallCallingConvs[Call];
}
private:
TargetMachine &TM;
const TargetData *TD;
TargetLoweringObjectFile &TLOF;
/// PointerTy - The type to use for pointers, usually i32 or i64.
///
MVT PointerTy;
/// IsLittleEndian - True if this is a little endian target.
///
bool IsLittleEndian;
/// UsesGlobalOffsetTable - True if this target uses a GOT for PIC codegen.
///
bool UsesGlobalOffsetTable;
/// 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;
/// 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;
/// ShiftAmountTy - The type to use for shift amounts, usually i8 or whatever
/// PointerTy is.
MVT ShiftAmountTy;
/// BooleanContents - Information about the contents of the high-bits in
/// boolean values held in a type wider than i1. See getBooleanContents.
BooleanContent BooleanContents;
/// SchedPreferenceInfo - The target scheduling preference: shortest possible
/// total cycles or lowest register usage.
SchedPreference SchedPreferenceInfo;
/// 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;
/// PrefLoopAlignment - The perferred loop alignment.
///
unsigned PrefLoopAlignment;
/// 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];
EVT 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).
EVT 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.
/// This array is accessed using VT.getSimpleVT(), so it is subject to
/// the MVT::MAX_ALLOWED_VALUETYPE * 2 bits.
uint64_t OpActions[MVT::MAX_ALLOWED_VALUETYPE/(sizeof(uint64_t)*4)][ISD::BUILTIN_OP_END];
/// LoadExtActions - 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 LoadExtActions[ISD::LAST_LOADEXT_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. The first
/// dimension is now the value_type for the reference. The second
/// dimension is the load [0] vs. store[1]. The third dimension
/// represents the various modes for load store.
uint8_t IndexedModeActions[MVT::LAST_VALUETYPE][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];
/// CondCodeActions - For each condition code (ISD::CondCode) keep a
/// LegalizeAction that indicates how instruction selection should
/// deal with the condition code.
uint64_t CondCodeActions[ISD::SETCC_INVALID];
ValueTypeActionImpl ValueTypeActions;
std::vector<std::pair<EVT, 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[(ISD::BUILTIN_OP_END+CHAR_BIT-1)/CHAR_BIT];
/// 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::SimpleValueType>, MVT::SimpleValueType>
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];
/// LibcallCallingConvs - Stores the CallingConv that should be used for each
/// libcall.
CallingConv::ID LibcallCallingConvs[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 can benefit from code placement
/// optimization.
bool benefitFromCodePlacementOpt;
};
} // end llvm namespace
#endif
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