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llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

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//===-- SelectionDAGISel.cpp - Implement the SelectionDAGISel class -------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements the SelectionDAGISel class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "isel"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/CallingConv.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/SchedulerRegistry.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/Target/MRegisterInfo.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Compiler.h"
#include <algorithm>
using namespace llvm;
#ifndef NDEBUG
static cl::opt<bool>
ViewISelDAGs("view-isel-dags", cl::Hidden,
cl::desc("Pop up a window to show isel dags as they are selected"));
static cl::opt<bool>
ViewSchedDAGs("view-sched-dags", cl::Hidden,
cl::desc("Pop up a window to show sched dags as they are processed"));
#else
static const bool ViewISelDAGs = 0, ViewSchedDAGs = 0;
#endif
//===---------------------------------------------------------------------===//
///
/// RegisterScheduler class - Track the registration of instruction schedulers.
///
//===---------------------------------------------------------------------===//
MachinePassRegistry RegisterScheduler::Registry;
//===---------------------------------------------------------------------===//
///
/// ISHeuristic command line option for instruction schedulers.
///
//===---------------------------------------------------------------------===//
namespace {
cl::opt<RegisterScheduler::FunctionPassCtor, false,
RegisterPassParser<RegisterScheduler> >
ISHeuristic("sched",
cl::init(&createDefaultScheduler),
cl::desc("Instruction schedulers available:"));
static RegisterScheduler
defaultListDAGScheduler("default", " Best scheduler for the target",
createDefaultScheduler);
} // namespace
namespace {
/// RegsForValue - This struct represents the physical registers that a
/// particular value is assigned and the type information about the value.
/// This is needed because values can be promoted into larger registers and
/// expanded into multiple smaller registers than the value.
struct VISIBILITY_HIDDEN RegsForValue {
/// Regs - This list hold the register (for legal and promoted values)
/// or register set (for expanded values) that the value should be assigned
/// to.
std::vector<unsigned> Regs;
/// RegVT - The value type of each register.
///
MVT::ValueType RegVT;
/// ValueVT - The value type of the LLVM value, which may be promoted from
/// RegVT or made from merging the two expanded parts.
MVT::ValueType ValueVT;
RegsForValue() : RegVT(MVT::Other), ValueVT(MVT::Other) {}
RegsForValue(unsigned Reg, MVT::ValueType regvt, MVT::ValueType valuevt)
: RegVT(regvt), ValueVT(valuevt) {
Regs.push_back(Reg);
}
RegsForValue(const std::vector<unsigned> &regs,
MVT::ValueType regvt, MVT::ValueType valuevt)
: Regs(regs), RegVT(regvt), ValueVT(valuevt) {
}
/// getCopyFromRegs - Emit a series of CopyFromReg nodes that copies from
/// this value and returns the result as a ValueVT value. This uses
/// Chain/Flag as the input and updates them for the output Chain/Flag.
SDOperand getCopyFromRegs(SelectionDAG &DAG,
SDOperand &Chain, SDOperand &Flag) const;
/// getCopyToRegs - Emit a series of CopyToReg nodes that copies the
/// specified value into the registers specified by this object. This uses
/// Chain/Flag as the input and updates them for the output Chain/Flag.
void getCopyToRegs(SDOperand Val, SelectionDAG &DAG,
SDOperand &Chain, SDOperand &Flag,
MVT::ValueType PtrVT) const;
/// AddInlineAsmOperands - Add this value to the specified inlineasm node
/// operand list. This adds the code marker and includes the number of
/// values added into it.
void AddInlineAsmOperands(unsigned Code, SelectionDAG &DAG,
std::vector<SDOperand> &Ops) const;
};
}
namespace llvm {
//===--------------------------------------------------------------------===//
/// createDefaultScheduler - This creates an instruction scheduler appropriate
/// for the target.
ScheduleDAG* createDefaultScheduler(SelectionDAGISel *IS,
SelectionDAG *DAG,
MachineBasicBlock *BB) {
TargetLowering &TLI = IS->getTargetLowering();
if (TLI.getSchedulingPreference() == TargetLowering::SchedulingForLatency) {
return createTDListDAGScheduler(IS, DAG, BB);
} else {
assert(TLI.getSchedulingPreference() ==
TargetLowering::SchedulingForRegPressure && "Unknown sched type!");
return createBURRListDAGScheduler(IS, DAG, BB);
}
}
//===--------------------------------------------------------------------===//
/// FunctionLoweringInfo - This contains information that is global to a
/// function that is used when lowering a region of the function.
class FunctionLoweringInfo {
public:
TargetLowering &TLI;
Function &Fn;
MachineFunction &MF;
SSARegMap *RegMap;
FunctionLoweringInfo(TargetLowering &TLI, Function &Fn,MachineFunction &MF);
/// MBBMap - A mapping from LLVM basic blocks to their machine code entry.
std::map<const BasicBlock*, MachineBasicBlock *> MBBMap;
/// ValueMap - Since we emit code for the function a basic block at a time,
/// we must remember which virtual registers hold the values for
/// cross-basic-block values.
DenseMap<const Value*, unsigned> ValueMap;
/// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in
/// the entry block. This allows the allocas to be efficiently referenced
/// anywhere in the function.
std::map<const AllocaInst*, int> StaticAllocaMap;
unsigned MakeReg(MVT::ValueType VT) {
return RegMap->createVirtualRegister(TLI.getRegClassFor(VT));
}
/// isExportedInst - Return true if the specified value is an instruction
/// exported from its block.
bool isExportedInst(const Value *V) {
return ValueMap.count(V);
}
unsigned CreateRegForValue(const Value *V);
unsigned InitializeRegForValue(const Value *V) {
unsigned &R = ValueMap[V];
assert(R == 0 && "Already initialized this value register!");
return R = CreateRegForValue(V);
}
};
}
/// isUsedOutsideOfDefiningBlock - Return true if this instruction is used by
/// PHI nodes or outside of the basic block that defines it, or used by a
/// switch instruction, which may expand to multiple basic blocks.
static bool isUsedOutsideOfDefiningBlock(Instruction *I) {
if (isa<PHINode>(I)) return true;
BasicBlock *BB = I->getParent();
for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; ++UI)
if (cast<Instruction>(*UI)->getParent() != BB || isa<PHINode>(*UI) ||
// FIXME: Remove switchinst special case.
isa<SwitchInst>(*UI))
return true;
return false;
}
/// isOnlyUsedInEntryBlock - If the specified argument is only used in the
/// entry block, return true. This includes arguments used by switches, since
/// the switch may expand into multiple basic blocks.
static bool isOnlyUsedInEntryBlock(Argument *A) {
BasicBlock *Entry = A->getParent()->begin();
for (Value::use_iterator UI = A->use_begin(), E = A->use_end(); UI != E; ++UI)
if (cast<Instruction>(*UI)->getParent() != Entry || isa<SwitchInst>(*UI))
return false; // Use not in entry block.
return true;
}
FunctionLoweringInfo::FunctionLoweringInfo(TargetLowering &tli,
Function &fn, MachineFunction &mf)
: TLI(tli), Fn(fn), MF(mf), RegMap(MF.getSSARegMap()) {
// Create a vreg for each argument register that is not dead and is used
// outside of the entry block for the function.
for (Function::arg_iterator AI = Fn.arg_begin(), E = Fn.arg_end();
AI != E; ++AI)
if (!isOnlyUsedInEntryBlock(AI))
InitializeRegForValue(AI);
// Initialize the mapping of values to registers. This is only set up for
// instruction values that are used outside of the block that defines
// them.
Function::iterator BB = Fn.begin(), EB = Fn.end();
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
if (ConstantInt *CUI = dyn_cast<ConstantInt>(AI->getArraySize())) {
const Type *Ty = AI->getAllocatedType();
uint64_t TySize = TLI.getTargetData()->getTypeSize(Ty);
unsigned Align =
std::max((unsigned)TLI.getTargetData()->getPrefTypeAlignment(Ty),
AI->getAlignment());
TySize *= CUI->getZExtValue(); // Get total allocated size.
if (TySize == 0) TySize = 1; // Don't create zero-sized stack objects.
StaticAllocaMap[AI] =
MF.getFrameInfo()->CreateStackObject((unsigned)TySize, Align);
}
for (; BB != EB; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
if (!I->use_empty() && isUsedOutsideOfDefiningBlock(I))
if (!isa<AllocaInst>(I) ||
!StaticAllocaMap.count(cast<AllocaInst>(I)))
InitializeRegForValue(I);
// Create an initial MachineBasicBlock for each LLVM BasicBlock in F. This
// also creates the initial PHI MachineInstrs, though none of the input
// operands are populated.
for (BB = Fn.begin(), EB = Fn.end(); BB != EB; ++BB) {
MachineBasicBlock *MBB = new MachineBasicBlock(BB);
MBBMap[BB] = MBB;
MF.getBasicBlockList().push_back(MBB);
// Create Machine PHI nodes for LLVM PHI nodes, lowering them as
// appropriate.
PHINode *PN;
for (BasicBlock::iterator I = BB->begin();(PN = dyn_cast<PHINode>(I)); ++I){
if (PN->use_empty()) continue;
MVT::ValueType VT = TLI.getValueType(PN->getType());
unsigned NumElements;
if (VT != MVT::Vector)
NumElements = TLI.getNumElements(VT);
else {
MVT::ValueType VT1,VT2;
NumElements =
TLI.getVectorTypeBreakdown(cast<VectorType>(PN->getType()),
VT1, VT2);
}
unsigned PHIReg = ValueMap[PN];
assert(PHIReg && "PHI node does not have an assigned virtual register!");
const TargetInstrInfo *TII = TLI.getTargetMachine().getInstrInfo();
for (unsigned i = 0; i != NumElements; ++i)
BuildMI(MBB, TII->get(TargetInstrInfo::PHI), PHIReg+i);
}
}
}
/// CreateRegForValue - Allocate the appropriate number of virtual registers of
/// the correctly promoted or expanded types. Assign these registers
/// consecutive vreg numbers and return the first assigned number.
unsigned FunctionLoweringInfo::CreateRegForValue(const Value *V) {
MVT::ValueType VT = TLI.getValueType(V->getType());
// The number of multiples of registers that we need, to, e.g., split up
// a <2 x int64> -> 4 x i32 registers.
unsigned NumVectorRegs = 1;
// If this is a vector type, figure out what type it will decompose into
// and how many of the elements it will use.
if (VT == MVT::Vector) {
const VectorType *PTy = cast<VectorType>(V->getType());
unsigned NumElts = PTy->getNumElements();
MVT::ValueType EltTy = TLI.getValueType(PTy->getElementType());
// Divide the input until we get to a supported size. This will always
// end with a scalar if the target doesn't support vectors.
while (NumElts > 1 && !TLI.isTypeLegal(getVectorType(EltTy, NumElts))) {
NumElts >>= 1;
NumVectorRegs <<= 1;
}
if (NumElts == 1)
VT = EltTy;
else
VT = getVectorType(EltTy, NumElts);
}
// The common case is that we will only create one register for this
// value. If we have that case, create and return the virtual register.
unsigned NV = TLI.getNumElements(VT);
if (NV == 1) {
// If we are promoting this value, pick the next largest supported type.
MVT::ValueType PromotedType = TLI.getTypeToTransformTo(VT);
unsigned Reg = MakeReg(PromotedType);
// If this is a vector of supported or promoted types (e.g. 4 x i16),
// create all of the registers.
for (unsigned i = 1; i != NumVectorRegs; ++i)
MakeReg(PromotedType);
return Reg;
}
// If this value is represented with multiple target registers, make sure
// to create enough consecutive registers of the right (smaller) type.
VT = TLI.getTypeToExpandTo(VT);
unsigned R = MakeReg(VT);
for (unsigned i = 1; i != NV*NumVectorRegs; ++i)
MakeReg(VT);
return R;
}
//===----------------------------------------------------------------------===//
/// SelectionDAGLowering - This is the common target-independent lowering
/// implementation that is parameterized by a TargetLowering object.
/// Also, targets can overload any lowering method.
///
namespace llvm {
class SelectionDAGLowering {
MachineBasicBlock *CurMBB;
DenseMap<const Value*, SDOperand> NodeMap;
/// PendingLoads - Loads are not emitted to the program immediately. We bunch
/// them up and then emit token factor nodes when possible. This allows us to
/// get simple disambiguation between loads without worrying about alias
/// analysis.
std::vector<SDOperand> PendingLoads;
/// Case - A pair of values to record the Value for a switch case, and the
/// case's target basic block.
typedef std::pair<Constant*, MachineBasicBlock*> Case;
typedef std::vector<Case>::iterator CaseItr;
typedef std::pair<CaseItr, CaseItr> CaseRange;
/// CaseRec - A struct with ctor used in lowering switches to a binary tree
/// of conditional branches.
struct CaseRec {
CaseRec(MachineBasicBlock *bb, Constant *lt, Constant *ge, CaseRange r) :
CaseBB(bb), LT(lt), GE(ge), Range(r) {}
/// CaseBB - The MBB in which to emit the compare and branch
MachineBasicBlock *CaseBB;
/// LT, GE - If nonzero, we know the current case value must be less-than or
/// greater-than-or-equal-to these Constants.
Constant *LT;
Constant *GE;
/// Range - A pair of iterators representing the range of case values to be
/// processed at this point in the binary search tree.
CaseRange Range;
};
/// The comparison function for sorting Case values.
struct CaseCmp {
bool operator () (const Case& C1, const Case& C2) {
assert(isa<ConstantInt>(C1.first) && isa<ConstantInt>(C2.first));
return cast<const ConstantInt>(C1.first)->getSExtValue() <
cast<const ConstantInt>(C2.first)->getSExtValue();
}
};
public:
// TLI - This is information that describes the available target features we
// need for lowering. This indicates when operations are unavailable,
// implemented with a libcall, etc.
TargetLowering &TLI;
SelectionDAG &DAG;
const TargetData *TD;
/// SwitchCases - Vector of CaseBlock structures used to communicate
/// SwitchInst code generation information.
std::vector<SelectionDAGISel::CaseBlock> SwitchCases;
SelectionDAGISel::JumpTable JT;
/// FuncInfo - Information about the function as a whole.
///
FunctionLoweringInfo &FuncInfo;
SelectionDAGLowering(SelectionDAG &dag, TargetLowering &tli,
FunctionLoweringInfo &funcinfo)
: TLI(tli), DAG(dag), TD(DAG.getTarget().getTargetData()),
JT(0,0,0,0), FuncInfo(funcinfo) {
}
/// getRoot - Return the current virtual root of the Selection DAG.
///
SDOperand getRoot() {
if (PendingLoads.empty())
return DAG.getRoot();
if (PendingLoads.size() == 1) {
SDOperand Root = PendingLoads[0];
DAG.setRoot(Root);
PendingLoads.clear();
return Root;
}
// Otherwise, we have to make a token factor node.
SDOperand Root = DAG.getNode(ISD::TokenFactor, MVT::Other,
&PendingLoads[0], PendingLoads.size());
PendingLoads.clear();
DAG.setRoot(Root);
return Root;
}
SDOperand CopyValueToVirtualRegister(Value *V, unsigned Reg);
void visit(Instruction &I) { visit(I.getOpcode(), I); }
void visit(unsigned Opcode, User &I) {
// Note: this doesn't use InstVisitor, because it has to work with
// ConstantExpr's in addition to instructions.
switch (Opcode) {
default: assert(0 && "Unknown instruction type encountered!");
abort();
// Build the switch statement using the Instruction.def file.
#define HANDLE_INST(NUM, OPCODE, CLASS) \
case Instruction::OPCODE:return visit##OPCODE((CLASS&)I);
#include "llvm/Instruction.def"
}
}
void setCurrentBasicBlock(MachineBasicBlock *MBB) { CurMBB = MBB; }
SDOperand getLoadFrom(const Type *Ty, SDOperand Ptr,
const Value *SV, SDOperand Root,
bool isVolatile);
SDOperand getIntPtrConstant(uint64_t Val) {
return DAG.getConstant(Val, TLI.getPointerTy());
}
SDOperand getValue(const Value *V);
void setValue(const Value *V, SDOperand NewN) {
SDOperand &N = NodeMap[V];
assert(N.Val == 0 && "Already set a value for this node!");
N = NewN;
}
RegsForValue GetRegistersForValue(const std::string &ConstrCode,
MVT::ValueType VT,
bool OutReg, bool InReg,
std::set<unsigned> &OutputRegs,
std::set<unsigned> &InputRegs);
void FindMergedConditions(Value *Cond, MachineBasicBlock *TBB,
MachineBasicBlock *FBB, MachineBasicBlock *CurBB,
unsigned Opc);
bool isExportableFromCurrentBlock(Value *V, const BasicBlock *FromBB);
void ExportFromCurrentBlock(Value *V);
// Terminator instructions.
void visitRet(ReturnInst &I);
void visitBr(BranchInst &I);
void visitSwitch(SwitchInst &I);
void visitUnreachable(UnreachableInst &I) { /* noop */ }
// Helper for visitSwitch
void visitSwitchCase(SelectionDAGISel::CaseBlock &CB);
void visitJumpTable(SelectionDAGISel::JumpTable &JT);
// These all get lowered before this pass.
void visitInvoke(InvokeInst &I) { assert(0 && "TODO"); }
void visitUnwind(UnwindInst &I) { assert(0 && "TODO"); }
void visitScalarBinary(User &I, unsigned OpCode);
void visitVectorBinary(User &I, unsigned OpCode);
void visitEitherBinary(User &I, unsigned ScalarOp, unsigned VectorOp);
void visitShift(User &I, unsigned Opcode);
void visitAdd(User &I) {
if (isa<VectorType>(I.getType()))
visitVectorBinary(I, ISD::VADD);
else if (I.getType()->isFloatingPoint())
visitScalarBinary(I, ISD::FADD);
else
visitScalarBinary(I, ISD::ADD);
}
void visitSub(User &I);
void visitMul(User &I) {
if (isa<VectorType>(I.getType()))
visitVectorBinary(I, ISD::VMUL);
else if (I.getType()->isFloatingPoint())
visitScalarBinary(I, ISD::FMUL);
else
visitScalarBinary(I, ISD::MUL);
}
void visitURem(User &I) { visitScalarBinary(I, ISD::UREM); }
void visitSRem(User &I) { visitScalarBinary(I, ISD::SREM); }
void visitFRem(User &I) { visitScalarBinary(I, ISD::FREM); }
void visitUDiv(User &I) { visitEitherBinary(I, ISD::UDIV, ISD::VUDIV); }
void visitSDiv(User &I) { visitEitherBinary(I, ISD::SDIV, ISD::VSDIV); }
void visitFDiv(User &I) { visitEitherBinary(I, ISD::FDIV, ISD::VSDIV); }
void visitAnd (User &I) { visitEitherBinary(I, ISD::AND, ISD::VAND ); }
void visitOr (User &I) { visitEitherBinary(I, ISD::OR, ISD::VOR ); }
void visitXor (User &I) { visitEitherBinary(I, ISD::XOR, ISD::VXOR ); }
void visitShl (User &I) { visitShift(I, ISD::SHL); }
void visitLShr(User &I) { visitShift(I, ISD::SRL); }
void visitAShr(User &I) { visitShift(I, ISD::SRA); }
void visitICmp(User &I);
void visitFCmp(User &I);
// Visit the conversion instructions
void visitTrunc(User &I);
void visitZExt(User &I);
void visitSExt(User &I);
void visitFPTrunc(User &I);
void visitFPExt(User &I);
void visitFPToUI(User &I);
void visitFPToSI(User &I);
void visitUIToFP(User &I);
void visitSIToFP(User &I);
void visitPtrToInt(User &I);
void visitIntToPtr(User &I);
void visitBitCast(User &I);
void visitExtractElement(User &I);
void visitInsertElement(User &I);
void visitShuffleVector(User &I);
void visitGetElementPtr(User &I);
void visitSelect(User &I);
void visitMalloc(MallocInst &I);
void visitFree(FreeInst &I);
void visitAlloca(AllocaInst &I);
void visitLoad(LoadInst &I);
void visitStore(StoreInst &I);
void visitPHI(PHINode &I) { } // PHI nodes are handled specially.
void visitCall(CallInst &I);
void visitInlineAsm(CallInst &I);
const char *visitIntrinsicCall(CallInst &I, unsigned Intrinsic);
void visitTargetIntrinsic(CallInst &I, unsigned Intrinsic);
void visitVAStart(CallInst &I);
void visitVAArg(VAArgInst &I);
void visitVAEnd(CallInst &I);
void visitVACopy(CallInst &I);
void visitMemIntrinsic(CallInst &I, unsigned Op);
void visitUserOp1(Instruction &I) {
assert(0 && "UserOp1 should not exist at instruction selection time!");
abort();
}
void visitUserOp2(Instruction &I) {
assert(0 && "UserOp2 should not exist at instruction selection time!");
abort();
}
};
} // end namespace llvm
SDOperand SelectionDAGLowering::getValue(const Value *V) {
SDOperand &N = NodeMap[V];
if (N.Val) return N;
const Type *VTy = V->getType();
MVT::ValueType VT = TLI.getValueType(VTy);
if (Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V))) {
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
visit(CE->getOpcode(), *CE);
SDOperand N1 = NodeMap[V];
assert(N1.Val && "visit didn't populate the ValueMap!");
return N1;
} else if (GlobalValue *GV = dyn_cast<GlobalValue>(C)) {
return N = DAG.getGlobalAddress(GV, VT);
} else if (isa<ConstantPointerNull>(C)) {
return N = DAG.getConstant(0, TLI.getPointerTy());
} else if (isa<UndefValue>(C)) {
if (!isa<VectorType>(VTy))
return N = DAG.getNode(ISD::UNDEF, VT);
// Create a VBUILD_VECTOR of undef nodes.
const VectorType *PTy = cast<VectorType>(VTy);
unsigned NumElements = PTy->getNumElements();
MVT::ValueType PVT = TLI.getValueType(PTy->getElementType());
SmallVector<SDOperand, 8> Ops;
Ops.assign(NumElements, DAG.getNode(ISD::UNDEF, PVT));
// Create a VConstant node with generic Vector type.
Ops.push_back(DAG.getConstant(NumElements, MVT::i32));
Ops.push_back(DAG.getValueType(PVT));
return N = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector,
&Ops[0], Ops.size());
} else if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
return N = DAG.getConstantFP(CFP->getValue(), VT);
} else if (const VectorType *PTy = dyn_cast<VectorType>(VTy)) {
unsigned NumElements = PTy->getNumElements();
MVT::ValueType PVT = TLI.getValueType(PTy->getElementType());
// Now that we know the number and type of the elements, push a
// Constant or ConstantFP node onto the ops list for each element of
// the packed constant.
SmallVector<SDOperand, 8> Ops;
if (ConstantVector *CP = dyn_cast<ConstantVector>(C)) {
for (unsigned i = 0; i != NumElements; ++i)
Ops.push_back(getValue(CP->getOperand(i)));
} else {
assert(isa<ConstantAggregateZero>(C) && "Unknown packed constant!");
SDOperand Op;
if (MVT::isFloatingPoint(PVT))
Op = DAG.getConstantFP(0, PVT);
else
Op = DAG.getConstant(0, PVT);
Ops.assign(NumElements, Op);
}
// Create a VBUILD_VECTOR node with generic Vector type.
Ops.push_back(DAG.getConstant(NumElements, MVT::i32));
Ops.push_back(DAG.getValueType(PVT));
return NodeMap[V] = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0],
Ops.size());
} else {
// Canonicalize all constant ints to be unsigned.
return N = DAG.getConstant(cast<ConstantInt>(C)->getZExtValue(),VT);
}
}
if (const AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
std::map<const AllocaInst*, int>::iterator SI =
FuncInfo.StaticAllocaMap.find(AI);
if (SI != FuncInfo.StaticAllocaMap.end())
return DAG.getFrameIndex(SI->second, TLI.getPointerTy());
}
DenseMap<const Value*, unsigned>::iterator VMI =
FuncInfo.ValueMap.find(V);
assert(VMI != FuncInfo.ValueMap.end() && "Value not in map!");
unsigned InReg = VMI->second;
// If this type is not legal, make it so now.
if (VT != MVT::Vector) {
if (TLI.getTypeAction(VT) == TargetLowering::Expand) {
// Source must be expanded. This input value is actually coming from the
// register pair VMI->second and VMI->second+1.
MVT::ValueType DestVT = TLI.getTypeToExpandTo(VT);
unsigned NumVals = TLI.getNumElements(VT);
N = DAG.getCopyFromReg(DAG.getEntryNode(), InReg, DestVT);
if (NumVals == 1)
N = DAG.getNode(ISD::BIT_CONVERT, VT, N);
else {
assert(NumVals == 2 && "1 to 4 (and more) expansion not implemented!");
N = DAG.getNode(ISD::BUILD_PAIR, VT, N,
DAG.getCopyFromReg(DAG.getEntryNode(), InReg+1, DestVT));
}
} else {
MVT::ValueType DestVT = TLI.getTypeToTransformTo(VT);
N = DAG.getCopyFromReg(DAG.getEntryNode(), InReg, DestVT);
if (TLI.getTypeAction(VT) == TargetLowering::Promote) // Promotion case
N = MVT::isFloatingPoint(VT)
? DAG.getNode(ISD::FP_ROUND, VT, N)
: DAG.getNode(ISD::TRUNCATE, VT, N);
}
} else {
// Otherwise, if this is a vector, make it available as a generic vector
// here.
MVT::ValueType PTyElementVT, PTyLegalElementVT;
const VectorType *PTy = cast<VectorType>(VTy);
unsigned NE = TLI.getVectorTypeBreakdown(PTy, PTyElementVT,
PTyLegalElementVT);
// Build a VBUILD_VECTOR with the input registers.
SmallVector<SDOperand, 8> Ops;
if (PTyElementVT == PTyLegalElementVT) {
// If the value types are legal, just VBUILD the CopyFromReg nodes.
for (unsigned i = 0; i != NE; ++i)
Ops.push_back(DAG.getCopyFromReg(DAG.getEntryNode(), InReg++,
PTyElementVT));
} else if (PTyElementVT < PTyLegalElementVT) {
// If the register was promoted, use TRUNCATE of FP_ROUND as appropriate.
for (unsigned i = 0; i != NE; ++i) {
SDOperand Op = DAG.getCopyFromReg(DAG.getEntryNode(), InReg++,
PTyElementVT);
if (MVT::isFloatingPoint(PTyElementVT))
Op = DAG.getNode(ISD::FP_ROUND, PTyElementVT, Op);
else
Op = DAG.getNode(ISD::TRUNCATE, PTyElementVT, Op);
Ops.push_back(Op);
}
} else {
// If the register was expanded, use BUILD_PAIR.
assert((NE & 1) == 0 && "Must expand into a multiple of 2 elements!");
for (unsigned i = 0; i != NE/2; ++i) {
SDOperand Op0 = DAG.getCopyFromReg(DAG.getEntryNode(), InReg++,
PTyElementVT);
SDOperand Op1 = DAG.getCopyFromReg(DAG.getEntryNode(), InReg++,
PTyElementVT);
Ops.push_back(DAG.getNode(ISD::BUILD_PAIR, VT, Op0, Op1));
}
}
Ops.push_back(DAG.getConstant(NE, MVT::i32));
Ops.push_back(DAG.getValueType(PTyLegalElementVT));
N = DAG.getNode(ISD::VBUILD_VECTOR, MVT::Vector, &Ops[0], Ops.size());
// Finally, use a VBIT_CONVERT to make this available as the appropriate
// vector type.
N = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, N,
DAG.getConstant(PTy->getNumElements(),
MVT::i32),
DAG.getValueType(TLI.getValueType(PTy->getElementType())));
}
return N;
}
void SelectionDAGLowering::visitRet(ReturnInst &I) {
if (I.getNumOperands() == 0) {
DAG.setRoot(DAG.getNode(ISD::RET, MVT::Other, getRoot()));
return;
}
SmallVector<SDOperand, 8> NewValues;
NewValues.push_back(getRoot());
for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
SDOperand RetOp = getValue(I.getOperand(i));
// If this is an integer return value, we need to promote it ourselves to
// the full width of a register, since LegalizeOp will use ANY_EXTEND rather
// than sign/zero.
// FIXME: C calling convention requires the return type to be promoted to
// at least 32-bit. But this is not necessary for non-C calling conventions.
if (MVT::isInteger(RetOp.getValueType()) &&
RetOp.getValueType() < MVT::i64) {
MVT::ValueType TmpVT;
if (TLI.getTypeAction(MVT::i32) == TargetLowering::Promote)
TmpVT = TLI.getTypeToTransformTo(MVT::i32);
else
TmpVT = MVT::i32;
const FunctionType *FTy = I.getParent()->getParent()->getFunctionType();
ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
if (FTy->paramHasAttr(0, FunctionType::SExtAttribute))
ExtendKind = ISD::SIGN_EXTEND;
if (FTy->paramHasAttr(0, FunctionType::ZExtAttribute))
ExtendKind = ISD::ZERO_EXTEND;
RetOp = DAG.getNode(ExtendKind, TmpVT, RetOp);
}
NewValues.push_back(RetOp);
NewValues.push_back(DAG.getConstant(false, MVT::i32));
}
DAG.setRoot(DAG.getNode(ISD::RET, MVT::Other,
&NewValues[0], NewValues.size()));
}
/// ExportFromCurrentBlock - If this condition isn't known to be exported from
/// the current basic block, add it to ValueMap now so that we'll get a
/// CopyTo/FromReg.
void SelectionDAGLowering::ExportFromCurrentBlock(Value *V) {
// No need to export constants.
if (!isa<Instruction>(V) && !isa<Argument>(V)) return;
// Already exported?
if (FuncInfo.isExportedInst(V)) return;
unsigned Reg = FuncInfo.InitializeRegForValue(V);
PendingLoads.push_back(CopyValueToVirtualRegister(V, Reg));
}
bool SelectionDAGLowering::isExportableFromCurrentBlock(Value *V,
const BasicBlock *FromBB) {
// The operands of the setcc have to be in this block. We don't know
// how to export them from some other block.
if (Instruction *VI = dyn_cast<Instruction>(V)) {
// Can export from current BB.
if (VI->getParent() == FromBB)
return true;
// Is already exported, noop.
return FuncInfo.isExportedInst(V);
}
// If this is an argument, we can export it if the BB is the entry block or
// if it is already exported.
if (isa<Argument>(V)) {
if (FromBB == &FromBB->getParent()->getEntryBlock())
return true;
// Otherwise, can only export this if it is already exported.
return FuncInfo.isExportedInst(V);
}
// Otherwise, constants can always be exported.
return true;
}
static bool InBlock(const Value *V, const BasicBlock *BB) {
if (const Instruction *I = dyn_cast<Instruction>(V))
return I->getParent() == BB;
return true;
}
/// FindMergedConditions - If Cond is an expression like
void SelectionDAGLowering::FindMergedConditions(Value *Cond,
MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
MachineBasicBlock *CurBB,
unsigned Opc) {
// If this node is not part of the or/and tree, emit it as a branch.
Instruction *BOp = dyn_cast<Instruction>(Cond);
if (!BOp || !(isa<BinaryOperator>(BOp) || isa<CmpInst>(BOp)) ||
(unsigned)BOp->getOpcode() != Opc || !BOp->hasOneUse() ||
BOp->getParent() != CurBB->getBasicBlock() ||
!InBlock(BOp->getOperand(0), CurBB->getBasicBlock()) ||
!InBlock(BOp->getOperand(1), CurBB->getBasicBlock())) {
const BasicBlock *BB = CurBB->getBasicBlock();
// If the leaf of the tree is a comparison, merge the condition into
// the caseblock.
if ((isa<ICmpInst>(Cond) || isa<FCmpInst>(Cond)) &&
// The operands of the cmp have to be in this block. We don't know
// how to export them from some other block. If this is the first block
// of the sequence, no exporting is needed.
(CurBB == CurMBB ||
(isExportableFromCurrentBlock(BOp->getOperand(0), BB) &&
isExportableFromCurrentBlock(BOp->getOperand(1), BB)))) {
BOp = cast<Instruction>(Cond);
ISD::CondCode Condition;
if (ICmpInst *IC = dyn_cast<ICmpInst>(Cond)) {
switch (IC->getPredicate()) {
default: assert(0 && "Unknown icmp predicate opcode!");
case ICmpInst::ICMP_EQ: Condition = ISD::SETEQ; break;
case ICmpInst::ICMP_NE: Condition = ISD::SETNE; break;
case ICmpInst::ICMP_SLE: Condition = ISD::SETLE; break;
case ICmpInst::ICMP_ULE: Condition = ISD::SETULE; break;
case ICmpInst::ICMP_SGE: Condition = ISD::SETGE; break;
case ICmpInst::ICMP_UGE: Condition = ISD::SETUGE; break;
case ICmpInst::ICMP_SLT: Condition = ISD::SETLT; break;
case ICmpInst::ICMP_ULT: Condition = ISD::SETULT; break;
case ICmpInst::ICMP_SGT: Condition = ISD::SETGT; break;
case ICmpInst::ICMP_UGT: Condition = ISD::SETUGT; break;
}
} else if (FCmpInst *FC = dyn_cast<FCmpInst>(Cond)) {
ISD::CondCode FPC, FOC;
switch (FC->getPredicate()) {
default: assert(0 && "Unknown fcmp predicate opcode!");
case FCmpInst::FCMP_FALSE: FOC = FPC = ISD::SETFALSE; break;
case FCmpInst::FCMP_OEQ: FOC = ISD::SETEQ; FPC = ISD::SETOEQ; break;
case FCmpInst::FCMP_OGT: FOC = ISD::SETGT; FPC = ISD::SETOGT; break;
case FCmpInst::FCMP_OGE: FOC = ISD::SETGE; FPC = ISD::SETOGE; break;
case FCmpInst::FCMP_OLT: FOC = ISD::SETLT; FPC = ISD::SETOLT; break;
case FCmpInst::FCMP_OLE: FOC = ISD::SETLE; FPC = ISD::SETOLE; break;
case FCmpInst::FCMP_ONE: FOC = ISD::SETNE; FPC = ISD::SETONE; break;
case FCmpInst::FCMP_ORD: FOC = ISD::SETEQ; FPC = ISD::SETO; break;
case FCmpInst::FCMP_UNO: FOC = ISD::SETNE; FPC = ISD::SETUO; break;
case FCmpInst::FCMP_UEQ: FOC = ISD::SETEQ; FPC = ISD::SETUEQ; break;
case FCmpInst::FCMP_UGT: FOC = ISD::SETGT; FPC = ISD::SETUGT; break;
case FCmpInst::FCMP_UGE: FOC = ISD::SETGE; FPC = ISD::SETUGE; break;
case FCmpInst::FCMP_ULT: FOC = ISD::SETLT; FPC = ISD::SETULT; break;
case FCmpInst::FCMP_ULE: FOC = ISD::SETLE; FPC = ISD::SETULE; break;
case FCmpInst::FCMP_UNE: FOC = ISD::SETNE; FPC = ISD::SETUNE; break;
case FCmpInst::FCMP_TRUE: FOC = FPC = ISD::SETTRUE; break;
}
if (FiniteOnlyFPMath())
Condition = FOC;
else
Condition = FPC;
} else {
Condition = ISD::SETEQ; // silence warning.
assert(0 && "Unknown compare instruction");
}
SelectionDAGISel::CaseBlock CB(Condition, BOp->getOperand(0),
BOp->getOperand(1), TBB, FBB, CurBB);
SwitchCases.push_back(CB);
return;
}
// Create a CaseBlock record representing this branch.
SelectionDAGISel::CaseBlock CB(ISD::SETEQ, Cond, ConstantInt::getTrue(),
TBB, FBB, CurBB);
SwitchCases.push_back(CB);
return;
}
// Create TmpBB after CurBB.
MachineFunction::iterator BBI = CurBB;
MachineBasicBlock *TmpBB = new MachineBasicBlock(CurBB->getBasicBlock());
CurBB->getParent()->getBasicBlockList().insert(++BBI, TmpBB);
if (Opc == Instruction::Or) {
// Codegen X | Y as:
// jmp_if_X TBB
// jmp TmpBB
// TmpBB:
// jmp_if_Y TBB
// jmp FBB
//
// Emit the LHS condition.
FindMergedConditions(BOp->getOperand(0), TBB, TmpBB, CurBB, Opc);
// Emit the RHS condition into TmpBB.
FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, Opc);
} else {
assert(Opc == Instruction::And && "Unknown merge op!");
// Codegen X & Y as:
// jmp_if_X TmpBB
// jmp FBB
// TmpBB:
// jmp_if_Y TBB
// jmp FBB
//
// This requires creation of TmpBB after CurBB.
// Emit the LHS condition.
FindMergedConditions(BOp->getOperand(0), TmpBB, FBB, CurBB, Opc);
// Emit the RHS condition into TmpBB.
FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, Opc);
}
}
/// If the set of cases should be emitted as a series of branches, return true.
/// If we should emit this as a bunch of and/or'd together conditions, return
/// false.
static bool
ShouldEmitAsBranches(const std::vector<SelectionDAGISel::CaseBlock> &Cases) {
if (Cases.size() != 2) return true;
// If this is two comparisons of the same values or'd or and'd together, they
// will get folded into a single comparison, so don't emit two blocks.
if ((Cases[0].CmpLHS == Cases[1].CmpLHS &&
Cases[0].CmpRHS == Cases[1].CmpRHS) ||
(Cases[0].CmpRHS == Cases[1].CmpLHS &&
Cases[0].CmpLHS == Cases[1].CmpRHS)) {
return false;
}
return true;
}
void SelectionDAGLowering::visitBr(BranchInst &I) {
// Update machine-CFG edges.
MachineBasicBlock *Succ0MBB = FuncInfo.MBBMap[I.getSuccessor(0)];
// Figure out which block is immediately after the current one.
MachineBasicBlock *NextBlock = 0;
MachineFunction::iterator BBI = CurMBB;
if (++BBI != CurMBB->getParent()->end())
NextBlock = BBI;
if (I.isUnconditional()) {
// If this is not a fall-through branch, emit the branch.
if (Succ0MBB != NextBlock)
DAG.setRoot(DAG.getNode(ISD::BR, MVT::Other, getRoot(),
DAG.getBasicBlock(Succ0MBB)));
// Update machine-CFG edges.
CurMBB->addSuccessor(Succ0MBB);
return;
}
// If this condition is one of the special cases we handle, do special stuff
// now.
Value *CondVal = I.getCondition();
MachineBasicBlock *Succ1MBB = FuncInfo.MBBMap[I.getSuccessor(1)];
// If this is a series of conditions that are or'd or and'd together, emit
// this as a sequence of branches instead of setcc's with and/or operations.
// For example, instead of something like:
// cmp A, B
// C = seteq
// cmp D, E
// F = setle
// or C, F
// jnz foo
// Emit:
// cmp A, B
// je foo
// cmp D, E
// jle foo
//
if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(CondVal)) {
if (BOp->hasOneUse() &&
(BOp->getOpcode() == Instruction::And ||
BOp->getOpcode() == Instruction::Or)) {
FindMergedConditions(BOp, Succ0MBB, Succ1MBB, CurMBB, BOp->getOpcode());
// If the compares in later blocks need to use values not currently
// exported from this block, export them now. This block should always
// be the first entry.
assert(SwitchCases[0].ThisBB == CurMBB && "Unexpected lowering!");
// Allow some cases to be rejected.
if (ShouldEmitAsBranches(SwitchCases)) {
for (unsigned i = 1, e = SwitchCases.size(); i != e; ++i) {
ExportFromCurrentBlock(SwitchCases[i].CmpLHS);
ExportFromCurrentBlock(SwitchCases[i].CmpRHS);
}
// Emit the branch for this block.
visitSwitchCase(SwitchCases[0]);
SwitchCases.erase(SwitchCases.begin());
return;
}
// Okay, we decided not to do this, remove any inserted MBB's and clear
// SwitchCases.
for (unsigned i = 1, e = SwitchCases.size(); i != e; ++i)
CurMBB->getParent()->getBasicBlockList().erase(SwitchCases[i].ThisBB);
SwitchCases.clear();
}
}
// Create a CaseBlock record representing this branch.
SelectionDAGISel::CaseBlock CB(ISD::SETEQ, CondVal, ConstantInt::getTrue(),
Succ0MBB, Succ1MBB, CurMBB);
// Use visitSwitchCase to actually insert the fast branch sequence for this
// cond branch.
visitSwitchCase(CB);
}
/// visitSwitchCase - Emits the necessary code to represent a single node in
/// the binary search tree resulting from lowering a switch instruction.
void SelectionDAGLowering::visitSwitchCase(SelectionDAGISel::CaseBlock &CB) {
SDOperand Cond;
SDOperand CondLHS = getValue(CB.CmpLHS);
// Build the setcc now, fold "(X == true)" to X and "(X == false)" to !X to
// handle common cases produced by branch lowering.
if (CB.CmpRHS == ConstantInt::getTrue() && CB.CC == ISD::SETEQ)
Cond = CondLHS;
else if (CB.CmpRHS == ConstantInt::getFalse() && CB.CC == ISD::SETEQ) {
SDOperand True = DAG.getConstant(1, CondLHS.getValueType());
Cond = DAG.getNode(ISD::XOR, CondLHS.getValueType(), CondLHS, True);
} else
Cond = DAG.getSetCC(MVT::i1, CondLHS, getValue(CB.CmpRHS), CB.CC);
// Set NextBlock to be the MBB immediately after the current one, if any.
// This is used to avoid emitting unnecessary branches to the next block.
MachineBasicBlock *NextBlock = 0;
MachineFunction::iterator BBI = CurMBB;
if (++BBI != CurMBB->getParent()->end())
NextBlock = BBI;
// If the lhs block is the next block, invert the condition so that we can
// fall through to the lhs instead of the rhs block.
if (CB.TrueBB == NextBlock) {
std::swap(CB.TrueBB, CB.FalseBB);
SDOperand True = DAG.getConstant(1, Cond.getValueType());
Cond = DAG.getNode(ISD::XOR, Cond.getValueType(), Cond, True);
}
SDOperand BrCond = DAG.getNode(ISD::BRCOND, MVT::Other, getRoot(), Cond,
DAG.getBasicBlock(CB.TrueBB));
if (CB.FalseBB == NextBlock)
DAG.setRoot(BrCond);
else
DAG.setRoot(DAG.getNode(ISD::BR, MVT::Other, BrCond,
DAG.getBasicBlock(CB.FalseBB)));
// Update successor info
CurMBB->addSuccessor(CB.TrueBB);
CurMBB->addSuccessor(CB.FalseBB);
}
void SelectionDAGLowering::visitJumpTable(SelectionDAGISel::JumpTable &JT) {
// Emit the code for the jump table
MVT::ValueType PTy = TLI.getPointerTy();
SDOperand Index = DAG.getCopyFromReg(getRoot(), JT.Reg, PTy);
SDOperand Table = DAG.getJumpTable(JT.JTI, PTy);
DAG.setRoot(DAG.getNode(ISD::BR_JT, MVT::Other, Index.getValue(1),
Table, Index));
return;
}
void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
// Figure out which block is immediately after the current one.
MachineBasicBlock *NextBlock = 0;
MachineFunction::iterator BBI = CurMBB;
if (++BBI != CurMBB->getParent()->end())
NextBlock = BBI;
MachineBasicBlock *Default = FuncInfo.MBBMap[I.getDefaultDest()];
// If there is only the default destination, branch to it if it is not the
// next basic block. Otherwise, just fall through.
if (I.getNumOperands() == 2) {
// Update machine-CFG edges.
// If this is not a fall-through branch, emit the branch.
if (Default != NextBlock)
DAG.setRoot(DAG.getNode(ISD::BR, MVT::Other, getRoot(),
DAG.getBasicBlock(Default)));
CurMBB->addSuccessor(Default);
return;
}
// If there are any non-default case statements, create a vector of Cases
// representing each one, and sort the vector so that we can efficiently
// create a binary search tree from them.
std::vector<Case> Cases;
for (unsigned i = 1; i < I.getNumSuccessors(); ++i) {
MachineBasicBlock *SMBB = FuncInfo.MBBMap[I.getSuccessor(i)];
Cases.push_back(Case(I.getSuccessorValue(i), SMBB));
}
std::sort(Cases.begin(), Cases.end(), CaseCmp());
// Get the Value to be switched on and default basic blocks, which will be
// inserted into CaseBlock records, representing basic blocks in the binary
// search tree.
Value *SV = I.getOperand(0);
// Get the MachineFunction which holds the current MBB. This is used during
// emission of jump tables, and when inserting any additional MBBs necessary
// to represent the switch.
MachineFunction *CurMF = CurMBB->getParent();
const BasicBlock *LLVMBB = CurMBB->getBasicBlock();
// If the switch has few cases (two or less) emit a series of specific
// tests.
if (Cases.size() < 3) {
// TODO: If any two of the cases has the same destination, and if one value
// is the same as the other, but has one bit unset that the other has set,
// use bit manipulation to do two compares at once. For example:
// "if (X == 6 || X == 4)" -> "if ((X|2) == 6)"
// Rearrange the case blocks so that the last one falls through if possible.
if (NextBlock && Default != NextBlock && Cases.back().second != NextBlock) {
// The last case block won't fall through into 'NextBlock' if we emit the
// branches in this order. See if rearranging a case value would help.
for (unsigned i = 0, e = Cases.size()-1; i != e; ++i) {
if (Cases[i].second == NextBlock) {
std::swap(Cases[i], Cases.back());
break;
}
}
}
// Create a CaseBlock record representing a conditional branch to
// the Case's target mbb if the value being switched on SV is equal
// to C.
MachineBasicBlock *CurBlock = CurMBB;
for (unsigned i = 0, e = Cases.size(); i != e; ++i) {
MachineBasicBlock *FallThrough;
if (i != e-1) {
FallThrough = new MachineBasicBlock(CurMBB->getBasicBlock());
CurMF->getBasicBlockList().insert(BBI, FallThrough);
} else {
// If the last case doesn't match, go to the default block.
FallThrough = Default;
}
SelectionDAGISel::CaseBlock CB(ISD::SETEQ, SV, Cases[i].first,
Cases[i].second, FallThrough, CurBlock);
// If emitting the first comparison, just call visitSwitchCase to emit the
// code into the current block. Otherwise, push the CaseBlock onto the
// vector to be later processed by SDISel, and insert the node's MBB
// before the next MBB.
if (CurBlock == CurMBB)
visitSwitchCase(CB);
else
SwitchCases.push_back(CB);
CurBlock = FallThrough;
}
return;
}
// If the switch has more than 5 blocks, and at least 31.25% dense, and the
// target supports indirect branches, then emit a jump table rather than
// lowering the switch to a binary tree of conditional branches.
if ((TLI.isOperationLegal(ISD::BR_JT, MVT::Other) ||
TLI.isOperationLegal(ISD::BRIND, MVT::Other)) &&
Cases.size() > 5) {
uint64_t First =cast<ConstantInt>(Cases.front().first)->getSExtValue();
uint64_t Last = cast<ConstantInt>(Cases.back().first)->getSExtValue();
double Density = (double)Cases.size() / (double)((Last - First) + 1ULL);
if (Density >= 0.3125) {
// Create a new basic block to hold the code for loading the address
// of the jump table, and jumping to it. Update successor information;
// we will either branch to the default case for the switch, or the jump
// table.
MachineBasicBlock *JumpTableBB = new MachineBasicBlock(LLVMBB);
CurMF->getBasicBlockList().insert(BBI, JumpTableBB);
CurMBB->addSuccessor(Default);
CurMBB->addSuccessor(JumpTableBB);
// Subtract the lowest switch case value from the value being switched on
// and conditional branch to default mbb if the result is greater than the
// difference between smallest and largest cases.
SDOperand SwitchOp = getValue(SV);
MVT::ValueType VT = SwitchOp.getValueType();
SDOperand SUB = DAG.getNode(ISD::SUB, VT, SwitchOp,
DAG.getConstant(First, VT));
// The SDNode we just created, which holds the value being switched on
// minus the the smallest case value, needs to be copied to a virtual
// register so it can be used as an index into the jump table in a
// subsequent basic block. This value may be smaller or larger than the
// target's pointer type, and therefore require extension or truncating.
if (VT > TLI.getPointerTy())
SwitchOp = DAG.getNode(ISD::TRUNCATE, TLI.getPointerTy(), SUB);
else
SwitchOp = DAG.getNode(ISD::ZERO_EXTEND, TLI.getPointerTy(), SUB);
unsigned JumpTableReg = FuncInfo.MakeReg(TLI.getPointerTy());
SDOperand CopyTo = DAG.getCopyToReg(getRoot(), JumpTableReg, SwitchOp);
// Emit the range check for the jump table, and branch to the default
// block for the switch statement if the value being switched on exceeds
// the largest case in the switch.
SDOperand CMP = DAG.getSetCC(TLI.getSetCCResultTy(), SUB,
DAG.getConstant(Last-First,VT), ISD::SETUGT);
DAG.setRoot(DAG.getNode(ISD::BRCOND, MVT::Other, CopyTo, CMP,
DAG.getBasicBlock(Default)));
// Build a vector of destination BBs, corresponding to each target
// of the jump table. If the value of the jump table slot corresponds to
// a case statement, push the case's BB onto the vector, otherwise, push
// the default BB.
std::vector<MachineBasicBlock*> DestBBs;
int64_t TEI = First;
for (CaseItr ii = Cases.begin(), ee = Cases.end(); ii != ee; ++TEI)
if (cast<ConstantInt>(ii->first)->getSExtValue() == TEI) {
DestBBs.push_back(ii->second);
++ii;
} else {
DestBBs.push_back(Default);
}
// Update successor info. Add one edge to each unique successor.
// Vector bool would be better, but vector<bool> is really slow.
std::vector<unsigned char> SuccsHandled;
SuccsHandled.resize(CurMBB->getParent()->getNumBlockIDs());
for (std::vector<MachineBasicBlock*>::iterator I = DestBBs.begin(),
E = DestBBs.end(); I != E; ++I) {
if (!SuccsHandled[(*I)->getNumber()]) {
SuccsHandled[(*I)->getNumber()] = true;
JumpTableBB->addSuccessor(*I);
}
}
// Create a jump table index for this jump table, or return an existing
// one.
unsigned JTI = CurMF->getJumpTableInfo()->getJumpTableIndex(DestBBs);
// Set the jump table information so that we can codegen it as a second
// MachineBasicBlock
JT.Reg = JumpTableReg;
JT.JTI = JTI;
JT.MBB = JumpTableBB;
JT.Default = Default;
return;
}
}
// Push the initial CaseRec onto the worklist
std::vector<CaseRec> CaseVec;
CaseVec.push_back(CaseRec(CurMBB,0,0,CaseRange(Cases.begin(),Cases.end())));
while (!CaseVec.empty()) {
// Grab a record representing a case range to process off the worklist
CaseRec CR = CaseVec.back();
CaseVec.pop_back();
// Size is the number of Cases represented by this range. If Size is 1,
// then we are processing a leaf of the binary search tree. Otherwise,
// we need to pick a pivot, and push left and right ranges onto the
// worklist.
unsigned Size = CR.Range.second - CR.Range.first;
if (Size == 1) {
// Create a CaseBlock record representing a conditional branch to
// the Case's target mbb if the value being switched on SV is equal
// to C. Otherwise, branch to default.
Constant *C = CR.Range.first->first;
MachineBasicBlock *Target = CR.Range.first->second;
SelectionDAGISel::CaseBlock CB(ISD::SETEQ, SV, C, Target, Default,
CR.CaseBB);
// If the MBB representing the leaf node is the current MBB, then just
// call visitSwitchCase to emit the code into the current block.
// Otherwise, push the CaseBlock onto the vector to be later processed
// by SDISel, and insert the node's MBB before the next MBB.
if (CR.CaseBB == CurMBB)
visitSwitchCase(CB);
else
SwitchCases.push_back(CB);
} else {
// split case range at pivot
CaseItr Pivot = CR.Range.first + (Size / 2);
CaseRange LHSR(CR.Range.first, Pivot);
CaseRange RHSR(Pivot, CR.Range.second);
Constant *C = Pivot->first;
MachineBasicBlock *FalseBB = 0, *TrueBB = 0;
// We know that we branch to the LHS if the Value being switched on is
// less than the Pivot value, C. We use this to optimize our binary
// tree a bit, by recognizing that if SV is greater than or equal to the
// LHS's Case Value, and that Case Value is exactly one less than the
// Pivot's Value, then we can branch directly to the LHS's Target,
// rather than creating a leaf node for it.
if ((LHSR.second - LHSR.first) == 1 &&
LHSR.first->first == CR.GE &&
cast<ConstantInt>(C)->getZExtValue() ==
(cast<ConstantInt>(CR.GE)->getZExtValue() + 1ULL)) {
TrueBB = LHSR.first->second;
} else {
TrueBB = new MachineBasicBlock(LLVMBB);
CurMF->getBasicBlockList().insert(BBI, TrueBB);
CaseVec.push_back(CaseRec(TrueBB, C, CR.GE, LHSR));
}
// Similar to the optimization above, if the Value being switched on is
// known to be less than the Constant CR.LT, and the current Case Value
// is CR.LT - 1, then we can branch directly to the target block for
// the current Case Value, rather than emitting a RHS leaf node for it.
if ((RHSR.second - RHSR.first) == 1 && CR.LT &&
cast<ConstantInt>(RHSR.first->first)->getZExtValue() ==
(cast<ConstantInt>(CR.LT)->getZExtValue() - 1ULL)) {
FalseBB = RHSR.first->second;
} else {
FalseBB = new MachineBasicBlock(LLVMBB);
CurMF->getBasicBlockList().insert(BBI, FalseBB);
CaseVec.push_back(CaseRec(FalseBB,CR.LT,C,RHSR));
}
// Create a CaseBlock record representing a conditional branch to
// the LHS node if the value being switched on SV is less than C.
// Otherwise, branch to LHS.
SelectionDAGISel::CaseBlock CB(ISD::SETLT, SV, C, TrueBB, FalseBB,
CR.CaseBB);
if (CR.CaseBB == CurMBB)
visitSwitchCase(CB);
else
SwitchCases.push_back(CB);
}
}
}
void SelectionDAGLowering::visitSub(User &I) {
// -0.0 - X --> fneg
const Type *Ty = I.getType();
if (isa<VectorType>(Ty)) {
visitVectorBinary(I, ISD::VSUB);
} else if (Ty->isFloatingPoint()) {
if (ConstantFP *CFP = dyn_cast<ConstantFP>(I.getOperand(0)))
if (CFP->isExactlyValue(-0.0)) {
SDOperand Op2 = getValue(I.getOperand(1));
setValue(&I, DAG.getNode(ISD::FNEG, Op2.getValueType(), Op2));
return;
}
visitScalarBinary(I, ISD::FSUB);
} else
visitScalarBinary(I, ISD::SUB);
}
void SelectionDAGLowering::visitScalarBinary(User &I, unsigned OpCode) {
SDOperand Op1 = getValue(I.getOperand(0));
SDOperand Op2 = getValue(I.getOperand(1));
setValue(&I, DAG.getNode(OpCode, Op1.getValueType(), Op1, Op2));
}
void
SelectionDAGLowering::visitVectorBinary(User &I, unsigned OpCode) {
assert(isa<VectorType>(I.getType()));
const VectorType *Ty = cast<VectorType>(I.getType());
SDOperand Typ = DAG.getValueType(TLI.getValueType(Ty->getElementType()));
setValue(&I, DAG.getNode(OpCode, MVT::Vector,
getValue(I.getOperand(0)),
getValue(I.getOperand(1)),
DAG.getConstant(Ty->getNumElements(), MVT::i32),
Typ));
}
void SelectionDAGLowering::visitEitherBinary(User &I, unsigned ScalarOp,
unsigned VectorOp) {
if (isa<VectorType>(I.getType()))
visitVectorBinary(I, VectorOp);
else
visitScalarBinary(I, ScalarOp);
}
void SelectionDAGLowering::visitShift(User &I, unsigned Opcode) {
SDOperand Op1 = getValue(I.getOperand(0));
SDOperand Op2 = getValue(I.getOperand(1));
if (TLI.getShiftAmountTy() < Op2.getValueType())
Op2 = DAG.getNode(ISD::TRUNCATE, TLI.getShiftAmountTy(), Op2);
else if (TLI.getShiftAmountTy() > Op2.getValueType())
Op2 = DAG.getNode(ISD::ANY_EXTEND, TLI.getShiftAmountTy(), Op2);
setValue(&I, DAG.getNode(Opcode, Op1.getValueType(), Op1, Op2));
}
void SelectionDAGLowering::visitICmp(User &I) {
ICmpInst::Predicate predicate = ICmpInst::BAD_ICMP_PREDICATE;
if (ICmpInst *IC = dyn_cast<ICmpInst>(&I))
predicate = IC->getPredicate();
else if (ConstantExpr *IC = dyn_cast<ConstantExpr>(&I))
predicate = ICmpInst::Predicate(IC->getPredicate());
SDOperand Op1 = getValue(I.getOperand(0));
SDOperand Op2 = getValue(I.getOperand(1));
ISD::CondCode Opcode;
switch (predicate) {
case ICmpInst::ICMP_EQ : Opcode = ISD::SETEQ; break;
case ICmpInst::ICMP_NE : Opcode = ISD::SETNE; break;
case ICmpInst::ICMP_UGT : Opcode = ISD::SETUGT; break;
case ICmpInst::ICMP_UGE : Opcode = ISD::SETUGE; break;
case ICmpInst::ICMP_ULT : Opcode = ISD::SETULT; break;
case ICmpInst::ICMP_ULE : Opcode = ISD::SETULE; break;
case ICmpInst::ICMP_SGT : Opcode = ISD::SETGT; break;
case ICmpInst::ICMP_SGE : Opcode = ISD::SETGE; break;
case ICmpInst::ICMP_SLT : Opcode = ISD::SETLT; break;
case ICmpInst::ICMP_SLE : Opcode = ISD::SETLE; break;
default:
assert(!"Invalid ICmp predicate value");
Opcode = ISD::SETEQ;
break;
}
setValue(&I, DAG.getSetCC(MVT::i1, Op1, Op2, Opcode));
}
void SelectionDAGLowering::visitFCmp(User &I) {
FCmpInst::Predicate predicate = FCmpInst::BAD_FCMP_PREDICATE;
if (FCmpInst *FC = dyn_cast<FCmpInst>(&I))
predicate = FC->getPredicate();
else if (ConstantExpr *FC = dyn_cast<ConstantExpr>(&I))
predicate = FCmpInst::Predicate(FC->getPredicate());
SDOperand Op1 = getValue(I.getOperand(0));
SDOperand Op2 = getValue(I.getOperand(1));
ISD::CondCode Condition, FOC, FPC;
switch (predicate) {
case FCmpInst::FCMP_FALSE: FOC = FPC = ISD::SETFALSE; break;
case FCmpInst::FCMP_OEQ: FOC = ISD::SETEQ; FPC = ISD::SETOEQ; break;
case FCmpInst::FCMP_OGT: FOC = ISD::SETGT; FPC = ISD::SETOGT; break;
case FCmpInst::FCMP_OGE: FOC = ISD::SETGE; FPC = ISD::SETOGE; break;
case FCmpInst::FCMP_OLT: FOC = ISD::SETLT; FPC = ISD::SETOLT; break;
case FCmpInst::FCMP_OLE: FOC = ISD::SETLE; FPC = ISD::SETOLE; break;
case FCmpInst::FCMP_ONE: FOC = ISD::SETNE; FPC = ISD::SETONE; break;
case FCmpInst::FCMP_ORD: FOC = ISD::SETEQ; FPC = ISD::SETO; break;
case FCmpInst::FCMP_UNO: FOC = ISD::SETNE; FPC = ISD::SETUO; break;
case FCmpInst::FCMP_UEQ: FOC = ISD::SETEQ; FPC = ISD::SETUEQ; break;
case FCmpInst::FCMP_UGT: FOC = ISD::SETGT; FPC = ISD::SETUGT; break;
case FCmpInst::FCMP_UGE: FOC = ISD::SETGE; FPC = ISD::SETUGE; break;
case FCmpInst::FCMP_ULT: FOC = ISD::SETLT; FPC = ISD::SETULT; break;
case FCmpInst::FCMP_ULE: FOC = ISD::SETLE; FPC = ISD::SETULE; break;
case FCmpInst::FCMP_UNE: FOC = ISD::SETNE; FPC = ISD::SETUNE; break;
case FCmpInst::FCMP_TRUE: FOC = FPC = ISD::SETTRUE; break;
default:
assert(!"Invalid FCmp predicate value");
FOC = FPC = ISD::SETFALSE;
break;
}
if (FiniteOnlyFPMath())
Condition = FOC;
else
Condition = FPC;
setValue(&I, DAG.getSetCC(MVT::i1, Op1, Op2, Condition));
}
void SelectionDAGLowering::visitSelect(User &I) {
SDOperand Cond = getValue(I.getOperand(0));
SDOperand TrueVal = getValue(I.getOperand(1));
SDOperand FalseVal = getValue(I.getOperand(2));
if (!isa<VectorType>(I.getType())) {
setValue(&I, DAG.getNode(ISD::SELECT, TrueVal.getValueType(), Cond,
TrueVal, FalseVal));
} else {
setValue(&I, DAG.getNode(ISD::VSELECT, MVT::Vector, Cond, TrueVal, FalseVal,
*(TrueVal.Val->op_end()-2),
*(TrueVal.Val->op_end()-1)));
}
}
void SelectionDAGLowering::visitTrunc(User &I) {
// TruncInst cannot be a no-op cast because sizeof(src) > sizeof(dest).
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::TRUNCATE, DestVT, N));
}
void SelectionDAGLowering::visitZExt(User &I) {
// ZExt cannot be a no-op cast because sizeof(src) < sizeof(dest).
// ZExt also can't be a cast to bool for same reason. So, nothing much to do
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::ZERO_EXTEND, DestVT, N));
}
void SelectionDAGLowering::visitSExt(User &I) {
// SExt cannot be a no-op cast because sizeof(src) < sizeof(dest).
// SExt also can't be a cast to bool for same reason. So, nothing much to do
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::SIGN_EXTEND, DestVT, N));
}
void SelectionDAGLowering::visitFPTrunc(User &I) {
// FPTrunc is never a no-op cast, no need to check
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::FP_ROUND, DestVT, N));
}
void SelectionDAGLowering::visitFPExt(User &I){
// FPTrunc is never a no-op cast, no need to check
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::FP_EXTEND, DestVT, N));
}
void SelectionDAGLowering::visitFPToUI(User &I) {
// FPToUI is never a no-op cast, no need to check
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::FP_TO_UINT, DestVT, N));
}
void SelectionDAGLowering::visitFPToSI(User &I) {
// FPToSI is never a no-op cast, no need to check
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::FP_TO_SINT, DestVT, N));
}
void SelectionDAGLowering::visitUIToFP(User &I) {
// UIToFP is never a no-op cast, no need to check
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::UINT_TO_FP, DestVT, N));
}
void SelectionDAGLowering::visitSIToFP(User &I){
// UIToFP is never a no-op cast, no need to check
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
setValue(&I, DAG.getNode(ISD::SINT_TO_FP, DestVT, N));
}
void SelectionDAGLowering::visitPtrToInt(User &I) {
// What to do depends on the size of the integer and the size of the pointer.
// We can either truncate, zero extend, or no-op, accordingly.
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType SrcVT = N.getValueType();
MVT::ValueType DestVT = TLI.getValueType(I.getType());
SDOperand Result;
if (MVT::getSizeInBits(DestVT) < MVT::getSizeInBits(SrcVT))
Result = DAG.getNode(ISD::TRUNCATE, DestVT, N);
else
// Note: ZERO_EXTEND can handle cases where the sizes are equal too
Result = DAG.getNode(ISD::ZERO_EXTEND, DestVT, N);
setValue(&I, Result);
}
void SelectionDAGLowering::visitIntToPtr(User &I) {
// What to do depends on the size of the integer and the size of the pointer.
// We can either truncate, zero extend, or no-op, accordingly.
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType SrcVT = N.getValueType();
MVT::ValueType DestVT = TLI.getValueType(I.getType());
if (MVT::getSizeInBits(DestVT) < MVT::getSizeInBits(SrcVT))
setValue(&I, DAG.getNode(ISD::TRUNCATE, DestVT, N));
else
// Note: ZERO_EXTEND can handle cases where the sizes are equal too
setValue(&I, DAG.getNode(ISD::ZERO_EXTEND, DestVT, N));
}
void SelectionDAGLowering::visitBitCast(User &I) {
SDOperand N = getValue(I.getOperand(0));
MVT::ValueType DestVT = TLI.getValueType(I.getType());
if (DestVT == MVT::Vector) {
// This is a cast to a vector from something else.
// Get information about the output vector.
const VectorType *DestTy = cast<VectorType>(I.getType());
MVT::ValueType EltVT = TLI.getValueType(DestTy->getElementType());
setValue(&I, DAG.getNode(ISD::VBIT_CONVERT, DestVT, N,
DAG.getConstant(DestTy->getNumElements(),MVT::i32),
DAG.getValueType(EltVT)));
return;
}
MVT::ValueType SrcVT = N.getValueType();
if (SrcVT == MVT::Vector) {
// This is a cast from a vctor to something else.
// Get information about the input vector.
setValue(&I, DAG.getNode(ISD::VBIT_CONVERT, DestVT, N));
return;
}
// BitCast assures us that source and destination are the same size so this
// is either a BIT_CONVERT or a no-op.
if (DestVT != N.getValueType())
setValue(&I, DAG.getNode(ISD::BIT_CONVERT, DestVT, N)); // convert types
else
setValue(&I, N); // noop cast.
}
void SelectionDAGLowering::visitInsertElement(User &I) {
SDOperand InVec = getValue(I.getOperand(0));
SDOperand InVal = getValue(I.getOperand(1));
SDOperand InIdx = DAG.getNode(ISD::ZERO_EXTEND, TLI.getPointerTy(),
getValue(I.getOperand(2)));
SDOperand Num = *(InVec.Val->op_end()-2);
SDOperand Typ = *(InVec.Val->op_end()-1);
setValue(&I, DAG.getNode(ISD::VINSERT_VECTOR_ELT, MVT::Vector,
InVec, InVal, InIdx, Num, Typ));
}
void SelectionDAGLowering::visitExtractElement(User &I) {
SDOperand InVec = getValue(I.getOperand(0));
SDOperand InIdx = DAG.getNode(ISD::ZERO_EXTEND, TLI.getPointerTy(),
getValue(I.getOperand(1)));
SDOperand Typ = *(InVec.Val->op_end()-1);
setValue(&I, DAG.getNode(ISD::VEXTRACT_VECTOR_ELT,
TLI.getValueType(I.getType()), InVec, InIdx));
}
void SelectionDAGLowering::visitShuffleVector(User &I) {
SDOperand V1 = getValue(I.getOperand(0));
SDOperand V2 = getValue(I.getOperand(1));
SDOperand Mask = getValue(I.getOperand(2));
SDOperand Num = *(V1.Val->op_end()-2);
SDOperand Typ = *(V2.Val->op_end()-1);
setValue(&I, DAG.getNode(ISD::VVECTOR_SHUFFLE, MVT::Vector,
V1, V2, Mask, Num, Typ));
}
void SelectionDAGLowering::visitGetElementPtr(User &I) {
SDOperand N = getValue(I.getOperand(0));
const Type *Ty = I.getOperand(0)->getType();
for (GetElementPtrInst::op_iterator OI = I.op_begin()+1, E = I.op_end();
OI != E; ++OI) {
Value *Idx = *OI;
if (const StructType *StTy = dyn_cast<StructType>(Ty)) {
unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
if (Field) {
// N = N + Offset
uint64_t Offset = TD->getStructLayout(StTy)->getElementOffset(Field);
N = DAG.getNode(ISD::ADD, N.getValueType(), N,
getIntPtrConstant(Offset));
}
Ty = StTy->getElementType(Field);
} else {
Ty = cast<SequentialType>(Ty)->getElementType();
// If this is a constant subscript, handle it quickly.
if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
if (CI->getZExtValue() == 0) continue;
uint64_t Offs =
TD->getTypeSize(Ty)*cast<ConstantInt>(CI)->getSExtValue();
N = DAG.getNode(ISD::ADD, N.getValueType(), N, getIntPtrConstant(Offs));
continue;
}
// N = N + Idx * ElementSize;
uint64_t ElementSize = TD->getTypeSize(Ty);
SDOperand IdxN = getValue(Idx);
// If the index is smaller or larger than intptr_t, truncate or extend
// it.
if (IdxN.getValueType() < N.getValueType()) {
IdxN = DAG.getNode(ISD::SIGN_EXTEND, N.getValueType(), IdxN);
} else if (IdxN.getValueType() > N.getValueType())
IdxN = DAG.getNode(ISD::TRUNCATE, N.getValueType(), IdxN);
// If this is a multiply by a power of two, turn it into a shl
// immediately. This is a very common case.
if (isPowerOf2_64(ElementSize)) {
unsigned Amt = Log2_64(ElementSize);
IdxN = DAG.getNode(ISD::SHL, N.getValueType(), IdxN,
DAG.getConstant(Amt, TLI.getShiftAmountTy()));
N = DAG.getNode(ISD::ADD, N.getValueType(), N, IdxN);
continue;
}
SDOperand Scale = getIntPtrConstant(ElementSize);
IdxN = DAG.getNode(ISD::MUL, N.getValueType(), IdxN, Scale);
N = DAG.getNode(ISD::ADD, N.getValueType(), N, IdxN);
}
}
setValue(&I, N);
}
void SelectionDAGLowering::visitAlloca(AllocaInst &I) {
// If this is a fixed sized alloca in the entry block of the function,
// allocate it statically on the stack.
if (FuncInfo.StaticAllocaMap.count(&I))
return; // getValue will auto-populate this.
const Type *Ty = I.getAllocatedType();
uint64_t TySize = TLI.getTargetData()->getTypeSize(Ty);
unsigned Align =
std::max((unsigned)TLI.getTargetData()->getPrefTypeAlignment(Ty),
I.getAlignment());
SDOperand AllocSize = getValue(I.getArraySize());
MVT::ValueType IntPtr = TLI.getPointerTy();
if (IntPtr < AllocSize.getValueType())
AllocSize = DAG.getNode(ISD::TRUNCATE, IntPtr, AllocSize);
else if (IntPtr > AllocSize.getValueType())
AllocSize = DAG.getNode(ISD::ZERO_EXTEND, IntPtr, AllocSize);
AllocSize = DAG.getNode(ISD::MUL, IntPtr, AllocSize,
getIntPtrConstant(TySize));
// Handle alignment. If the requested alignment is less than or equal to the
// stack alignment, ignore it and round the size of the allocation up to the
// stack alignment size. If the size is greater than the stack alignment, we
// note this in the DYNAMIC_STACKALLOC node.
unsigned StackAlign =
TLI.getTargetMachine().getFrameInfo()->getStackAlignment();
if (Align <= StackAlign) {
Align = 0;
// Add SA-1 to the size.
AllocSize = DAG.getNode(ISD::ADD, AllocSize.getValueType(), AllocSize,
getIntPtrConstant(StackAlign-1));
// Mask out the low bits for alignment purposes.
AllocSize = DAG.getNode(ISD::AND, AllocSize.getValueType(), AllocSize,
getIntPtrConstant(~(uint64_t)(StackAlign-1)));
}
SDOperand Ops[] = { getRoot(), AllocSize, getIntPtrConstant(Align) };
const MVT::ValueType *VTs = DAG.getNodeValueTypes(AllocSize.getValueType(),
MVT::Other);
SDOperand DSA = DAG.getNode(ISD::DYNAMIC_STACKALLOC, VTs, 2, Ops, 3);
setValue(&I, DSA);
DAG.setRoot(DSA.getValue(1));
// Inform the Frame Information that we have just allocated a variable-sized
// object.
CurMBB->getParent()->getFrameInfo()->CreateVariableSizedObject();
}
void SelectionDAGLowering::visitLoad(LoadInst &I) {
SDOperand Ptr = getValue(I.getOperand(0));
SDOperand Root;
if (I.isVolatile())
Root = getRoot();
else {
// Do not serialize non-volatile loads against each other.
Root = DAG.getRoot();
}
setValue(&I, getLoadFrom(I.getType(), Ptr, I.getOperand(0),
Root, I.isVolatile()));
}
SDOperand SelectionDAGLowering::getLoadFrom(const Type *Ty, SDOperand Ptr,
const Value *SV, SDOperand Root,
bool isVolatile) {
SDOperand L;
if (const VectorType *PTy = dyn_cast<VectorType>(Ty)) {
MVT::ValueType PVT = TLI.getValueType(PTy->getElementType());
L = DAG.getVecLoad(PTy->getNumElements(), PVT, Root, Ptr,
DAG.getSrcValue(SV));
} else {
L = DAG.getLoad(TLI.getValueType(Ty), Root, Ptr, SV, 0, isVolatile);
}
if (isVolatile)
DAG.setRoot(L.getValue(1));
else
PendingLoads.push_back(L.getValue(1));
return L;
}
void SelectionDAGLowering::visitStore(StoreInst &I) {
Value *SrcV = I.getOperand(0);
SDOperand Src = getValue(SrcV);
SDOperand Ptr = getValue(I.getOperand(1));
DAG.setRoot(DAG.getStore(getRoot(), Src, Ptr, I.getOperand(1), 0,
I.isVolatile()));
}
/// IntrinsicCannotAccessMemory - Return true if the specified intrinsic cannot
/// access memory and has no other side effects at all.
static bool IntrinsicCannotAccessMemory(unsigned IntrinsicID) {
#define GET_NO_MEMORY_INTRINSICS
#include "llvm/Intrinsics.gen"
#undef GET_NO_MEMORY_INTRINSICS
return false;
}
// IntrinsicOnlyReadsMemory - Return true if the specified intrinsic doesn't
// have any side-effects or if it only reads memory.
static bool IntrinsicOnlyReadsMemory(unsigned IntrinsicID) {
#define GET_SIDE_EFFECT_INFO
#include "llvm/Intrinsics.gen"
#undef GET_SIDE_EFFECT_INFO
return false;
}
/// visitTargetIntrinsic - Lower a call of a target intrinsic to an INTRINSIC
/// node.
void SelectionDAGLowering::visitTargetIntrinsic(CallInst &I,
unsigned Intrinsic) {
bool HasChain = !IntrinsicCannotAccessMemory(Intrinsic);
bool OnlyLoad = HasChain && IntrinsicOnlyReadsMemory(Intrinsic);
// Build the operand list.
SmallVector<SDOperand, 8> Ops;
if (HasChain) { // If this intrinsic has side-effects, chainify it.
if (OnlyLoad) {
// We don't need to serialize loads against other loads.
Ops.push_back(DAG.getRoot());
} else {
Ops.push_back(getRoot());
}
}
// Add the intrinsic ID as an integer operand.
Ops.push_back(DAG.getConstant(Intrinsic, TLI.getPointerTy()));
// Add all operands of the call to the operand list.
for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i) {
SDOperand Op = getValue(I.getOperand(i));
// If this is a vector type, force it to the right vector type.
if (Op.getValueType() == MVT::Vector) {
const VectorType *OpTy = cast<VectorType>(I.getOperand(i)->getType());
MVT::ValueType EltVT = TLI.getValueType(OpTy->getElementType());
MVT::ValueType VVT = MVT::getVectorType(EltVT, OpTy->getNumElements());
assert(VVT != MVT::Other && "Intrinsic uses a non-legal type?");
Op = DAG.getNode(ISD::VBIT_CONVERT, VVT, Op);
}
assert(TLI.isTypeLegal(Op.getValueType()) &&
"Intrinsic uses a non-legal type?");
Ops.push_back(Op);
}
std::vector<MVT::ValueType> VTs;
if (I.getType() != Type::VoidTy) {
MVT::ValueType VT = TLI.getValueType(I.getType());
if (VT == MVT::Vector) {
const VectorType *DestTy = cast<VectorType>(I.getType());
MVT::ValueType EltVT = TLI.getValueType(DestTy->getElementType());
VT = MVT::getVectorType(EltVT, DestTy->getNumElements());
assert(VT != MVT::Other && "Intrinsic uses a non-legal type?");
}
assert(TLI.isTypeLegal(VT) && "Intrinsic uses a non-legal type?");
VTs.push_back(VT);
}
if (HasChain)
VTs.push_back(MVT::Other);
const MVT::ValueType *VTList = DAG.getNodeValueTypes(VTs);
// Create the node.
SDOperand Result;
if (!HasChain)
Result = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, VTList, VTs.size(),
&Ops[0], Ops.size());
else if (I.getType() != Type::VoidTy)
Result = DAG.getNode(ISD::INTRINSIC_W_CHAIN, VTList, VTs.size(),
&Ops[0], Ops.size());
else
Result = DAG.getNode(ISD::INTRINSIC_VOID, VTList, VTs.size(),
&Ops[0], Ops.size());
if (HasChain) {
SDOperand Chain = Result.getValue(Result.Val->getNumValues()-1);
if (OnlyLoad)
PendingLoads.push_back(Chain);
else
DAG.setRoot(Chain);
}
if (I.getType() != Type::VoidTy) {
if (const VectorType *PTy = dyn_cast<VectorType>(I.getType())) {
MVT::ValueType EVT = TLI.getValueType(PTy->getElementType());
Result = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, Result,
DAG.getConstant(PTy->getNumElements(), MVT::i32),
DAG.getValueType(EVT));
}
setValue(&I, Result);
}
}
/// visitIntrinsicCall - Lower the call to the specified intrinsic function. If
/// we want to emit this as a call to a named external function, return the name
/// otherwise lower it and return null.
const char *
SelectionDAGLowering::visitIntrinsicCall(CallInst &I, unsigned Intrinsic) {
switch (Intrinsic) {
default:
// By default, turn this into a target intrinsic node.
visitTargetIntrinsic(I, Intrinsic);
return 0;
case Intrinsic::vastart: visitVAStart(I); return 0;
case Intrinsic::vaend: visitVAEnd(I); return 0;
case Intrinsic::vacopy: visitVACopy(I); return 0;
case Intrinsic::returnaddress:
setValue(&I, DAG.getNode(ISD::RETURNADDR, TLI.getPointerTy(),
getValue(I.getOperand(1))));
return 0;
case Intrinsic::frameaddress:
setValue(&I, DAG.getNode(ISD::FRAMEADDR, TLI.getPointerTy(),
getValue(I.getOperand(1))));
return 0;
case Intrinsic::setjmp:
return "_setjmp"+!TLI.usesUnderscoreSetJmp();
break;
case Intrinsic::longjmp:
return "_longjmp"+!TLI.usesUnderscoreLongJmp();
break;
case Intrinsic::memcpy_i32:
case Intrinsic::memcpy_i64:
visitMemIntrinsic(I, ISD::MEMCPY);
return 0;
case Intrinsic::memset_i32:
case Intrinsic::memset_i64:
visitMemIntrinsic(I, ISD::MEMSET);
return 0;
case Intrinsic::memmove_i32:
case Intrinsic::memmove_i64:
visitMemIntrinsic(I, ISD::MEMMOVE);
return 0;
case Intrinsic::dbg_stoppoint: {
MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
DbgStopPointInst &SPI = cast<DbgStopPointInst>(I);
if (MMI && SPI.getContext() && MMI->Verify(SPI.getContext())) {
SDOperand Ops[5];
Ops[0] = getRoot();
Ops[1] = getValue(SPI.getLineValue());
Ops[2] = getValue(SPI.getColumnValue());
DebugInfoDesc *DD = MMI->getDescFor(SPI.getContext());
assert(DD && "Not a debug information descriptor");
CompileUnitDesc *CompileUnit = cast<CompileUnitDesc>(DD);
Ops[3] = DAG.getString(CompileUnit->getFileName());
Ops[4] = DAG.getString(CompileUnit->getDirectory());
DAG.setRoot(DAG.getNode(ISD::LOCATION, MVT::Other, Ops, 5));
}
return 0;
}
case Intrinsic::dbg_region_start: {
MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
DbgRegionStartInst &RSI = cast<DbgRegionStartInst>(I);
if (MMI && RSI.getContext() && MMI->Verify(RSI.getContext())) {
unsigned LabelID = MMI->RecordRegionStart(RSI.getContext());
DAG.setRoot(DAG.getNode(ISD::LABEL, MVT::Other, getRoot(),
DAG.getConstant(LabelID, MVT::i32)));
}
return 0;
}
case Intrinsic::dbg_region_end: {
MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
DbgRegionEndInst &REI = cast<DbgRegionEndInst>(I);
if (MMI && REI.getContext() && MMI->Verify(REI.getContext())) {
unsigned LabelID = MMI->RecordRegionEnd(REI.getContext());
DAG.setRoot(DAG.getNode(ISD::LABEL, MVT::Other,
getRoot(), DAG.getConstant(LabelID, MVT::i32)));
}
return 0;
}
case Intrinsic::dbg_func_start: {
MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
DbgFuncStartInst &FSI = cast<DbgFuncStartInst>(I);
if (MMI && FSI.getSubprogram() &&
MMI->Verify(FSI.getSubprogram())) {
unsigned LabelID = MMI->RecordRegionStart(FSI.getSubprogram());
DAG.setRoot(DAG.getNode(ISD::LABEL, MVT::Other,
getRoot(), DAG.getConstant(LabelID, MVT::i32)));
}
return 0;
}
case Intrinsic::dbg_declare: {
MachineModuleInfo *MMI = DAG.getMachineModuleInfo();
DbgDeclareInst &DI = cast<DbgDeclareInst>(I);
if (MMI && DI.getVariable() && MMI->Verify(DI.getVariable())) {
SDOperand AddressOp = getValue(DI.getAddress());
if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(AddressOp))
MMI->RecordVariable(DI.getVariable(), FI->getIndex());
}
return 0;
}
case Intrinsic::sqrt_f32:
case Intrinsic::sqrt_f64:
setValue(&I, DAG.getNode(ISD::FSQRT,
getValue(I.getOperand(1)).getValueType(),
getValue(I.getOperand(1))));
return 0;
case Intrinsic::powi_f32:
case Intrinsic::powi_f64:
setValue(&I, DAG.getNode(ISD::FPOWI,
getValue(I.getOperand(1)).getValueType(),
getValue(I.getOperand(1)),
getValue(I.getOperand(2))));
return 0;
case Intrinsic::pcmarker: {
SDOperand Tmp = getValue(I.getOperand(1));
DAG.setRoot(DAG.getNode(ISD::PCMARKER, MVT::Other, getRoot(), Tmp));
return 0;
}
case Intrinsic::readcyclecounter: {
SDOperand Op = getRoot();
SDOperand Tmp = DAG.getNode(ISD::READCYCLECOUNTER,
DAG.getNodeValueTypes(MVT::i64, MVT::Other), 2,
&Op, 1);
setValue(&I, Tmp);
DAG.setRoot(Tmp.getValue(1));
return 0;
}
case Intrinsic::bswap_i16:
case Intrinsic::bswap_i32:
case Intrinsic::bswap_i64:
setValue(&I, DAG.getNode(ISD::BSWAP,
getValue(I.getOperand(1)).getValueType(),
getValue(I.getOperand(1))));
return 0;
case Intrinsic::cttz_i8:
case Intrinsic::cttz_i16:
case Intrinsic::cttz_i32:
case Intrinsic::cttz_i64:
setValue(&I, DAG.getNode(ISD::CTTZ,
getValue(I.getOperand(1)).getValueType(),
getValue(I.getOperand(1))));
return 0;
case Intrinsic::ctlz_i8:
case Intrinsic::ctlz_i16:
case Intrinsic::ctlz_i32:
case Intrinsic::ctlz_i64:
setValue(&I, DAG.getNode(ISD::CTLZ,
getValue(I.getOperand(1)).getValueType(),
getValue(I.getOperand(1))));
return 0;
case Intrinsic::ctpop_i8:
case Intrinsic::ctpop_i16:
case Intrinsic::ctpop_i32:
case Intrinsic::ctpop_i64:
setValue(&I, DAG.getNode(ISD::CTPOP,
getValue(I.getOperand(1)).getValueType(),
getValue(I.getOperand(1))));
return 0;
case Intrinsic::stacksave: {
SDOperand Op = getRoot();
SDOperand Tmp = DAG.getNode(ISD::STACKSAVE,
DAG.getNodeValueTypes(TLI.getPointerTy(), MVT::Other), 2, &Op, 1);
setValue(&I, Tmp);
DAG.setRoot(Tmp.getValue(1));
return 0;
}
case Intrinsic::stackrestore: {
SDOperand Tmp = getValue(I.getOperand(1));
DAG.setRoot(DAG.getNode(ISD::STACKRESTORE, MVT::Other, getRoot(), Tmp));
return 0;
}
case Intrinsic::prefetch:
// FIXME: Currently discarding prefetches.
return 0;
}
}
void SelectionDAGLowering::visitCall(CallInst &I) {
const char *RenameFn = 0;
if (Function *F = I.getCalledFunction()) {
if (F->isDeclaration())
if (unsigned IID = F->getIntrinsicID()) {
RenameFn = visitIntrinsicCall(I, IID);
if (!RenameFn)
return;
} else { // Not an LLVM intrinsic.
const std::string &Name = F->getName();
if (Name[0] == 'c' && (Name == "copysign" || Name == "copysignf")) {
if (I.getNumOperands() == 3 && // Basic sanity checks.
I.getOperand(1)->getType()->isFloatingPoint() &&
I.getType() == I.getOperand(1)->getType() &&
I.getType() == I.getOperand(2)->getType()) {
SDOperand LHS = getValue(I.getOperand(1));
SDOperand RHS = getValue(I.getOperand(2));
setValue(&I, DAG.getNode(ISD::FCOPYSIGN, LHS.getValueType(),
LHS, RHS));
return;
}
} else if (Name[0] == 'f' && (Name == "fabs" || Name == "fabsf")) {
if (I.getNumOperands() == 2 && // Basic sanity checks.
I.getOperand(1)->getType()->isFloatingPoint() &&
I.getType() == I.getOperand(1)->getType()) {
SDOperand Tmp = getValue(I.getOperand(1));
setValue(&I, DAG.getNode(ISD::FABS, Tmp.getValueType(), Tmp));
return;
}
} else if (Name[0] == 's' && (Name == "sin" || Name == "sinf")) {
if (I.getNumOperands() == 2 && // Basic sanity checks.
I.getOperand(1)->getType()->isFloatingPoint() &&
I.getType() == I.getOperand(1)->getType()) {
SDOperand Tmp = getValue(I.getOperand(1));
setValue(&I, DAG.getNode(ISD::FSIN, Tmp.getValueType(), Tmp));
return;
}
} else if (Name[0] == 'c' && (Name == "cos" || Name == "cosf")) {
if (I.getNumOperands() == 2 && // Basic sanity checks.
I.getOperand(1)->getType()->isFloatingPoint() &&
I.getType() == I.getOperand(1)->getType()) {
SDOperand Tmp = getValue(I.getOperand(1));
setValue(&I, DAG.getNode(ISD::FCOS, Tmp.getValueType(), Tmp));
return;
}
}
}
} else if (isa<InlineAsm>(I.getOperand(0))) {
visitInlineAsm(I);
return;
}
const PointerType *PT = cast<PointerType>(I.getCalledValue()->getType());
const FunctionType *FTy = cast<FunctionType>(PT->getElementType());
SDOperand Callee;
if (!RenameFn)
Callee = getValue(I.getOperand(0));
else
Callee = DAG.getExternalSymbol(RenameFn, TLI.getPointerTy());
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
Args.reserve(I.getNumOperands());
for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i) {
Value *Arg = I.getOperand(i);
SDOperand ArgNode = getValue(Arg);
Entry.Node = ArgNode; Entry.Ty = Arg->getType();
Entry.isSigned = FTy->paramHasAttr(i, FunctionType::SExtAttribute);
Entry.isInReg = FTy->paramHasAttr(i, FunctionType::InRegAttribute);
Entry.isSRet = FTy->paramHasAttr(i, FunctionType::StructRetAttribute);
Args.push_back(Entry);
}
std::pair<SDOperand,SDOperand> Result =
TLI.LowerCallTo(getRoot(), I.getType(),
FTy->paramHasAttr(0,FunctionType::SExtAttribute),
FTy->isVarArg(), I.getCallingConv(), I.isTailCall(),
Callee, Args, DAG);
if (I.getType() != Type::VoidTy)
setValue(&I, Result.first);
DAG.setRoot(Result.second);
}
SDOperand RegsForValue::getCopyFromRegs(SelectionDAG &DAG,
SDOperand &Chain, SDOperand &Flag)const{
SDOperand Val = DAG.getCopyFromReg(Chain, Regs[0], RegVT, Flag);
Chain = Val.getValue(1);
Flag = Val.getValue(2);
// If the result was expanded, copy from the top part.
if (Regs.size() > 1) {
assert(Regs.size() == 2 &&
"Cannot expand to more than 2 elts yet!");
SDOperand Hi = DAG.getCopyFromReg(Chain, Regs[1], RegVT, Flag);
Chain = Hi.getValue(1);
Flag = Hi.getValue(2);
if (DAG.getTargetLoweringInfo().isLittleEndian())
return DAG.getNode(ISD::BUILD_PAIR, ValueVT, Val, Hi);
else
return DAG.getNode(ISD::BUILD_PAIR, ValueVT, Hi, Val);
}
// Otherwise, if the return value was promoted or extended, truncate it to the
// appropriate type.
if (RegVT == ValueVT)
return Val;
if (MVT::isInteger(RegVT)) {
if (ValueVT < RegVT)
return DAG.getNode(ISD::TRUNCATE, ValueVT, Val);
else
return DAG.getNode(ISD::ANY_EXTEND, ValueVT, Val);
} else {
return DAG.getNode(ISD::FP_ROUND, ValueVT, Val);
}
}
/// getCopyToRegs - Emit a series of CopyToReg nodes that copies the
/// specified value into the registers specified by this object. This uses
/// Chain/Flag as the input and updates them for the output Chain/Flag.
void RegsForValue::getCopyToRegs(SDOperand Val, SelectionDAG &DAG,
SDOperand &Chain, SDOperand &Flag,
MVT::ValueType PtrVT) const {
if (Regs.size() == 1) {
// If there is a single register and the types differ, this must be
// a promotion.
if (RegVT != ValueVT) {
if (MVT::isInteger(RegVT)) {
if (RegVT < ValueVT)
Val = DAG.getNode(ISD::TRUNCATE, RegVT, Val);
else
Val = DAG.getNode(ISD::ANY_EXTEND, RegVT, Val);
} else
Val = DAG.getNode(ISD::FP_EXTEND, RegVT, Val);
}
Chain = DAG.getCopyToReg(Chain, Regs[0], Val, Flag);
Flag = Chain.getValue(1);
} else {
std::vector<unsigned> R(Regs);
if (!DAG.getTargetLoweringInfo().isLittleEndian())
std::reverse(R.begin(), R.end());
for (unsigned i = 0, e = R.size(); i != e; ++i) {
SDOperand Part = DAG.getNode(ISD::EXTRACT_ELEMENT, RegVT, Val,
DAG.getConstant(i, PtrVT));
Chain = DAG.getCopyToReg(Chain, R[i], Part, Flag);
Flag = Chain.getValue(1);
}
}
}
/// AddInlineAsmOperands - Add this value to the specified inlineasm node
/// operand list. This adds the code marker and includes the number of
/// values added into it.
void RegsForValue::AddInlineAsmOperands(unsigned Code, SelectionDAG &DAG,
std::vector<SDOperand> &Ops) const {
Ops.push_back(DAG.getConstant(Code | (Regs.size() << 3), MVT::i32));
for (unsigned i = 0, e = Regs.size(); i != e; ++i)
Ops.push_back(DAG.getRegister(Regs[i], RegVT));
}
/// isAllocatableRegister - If the specified register is safe to allocate,
/// i.e. it isn't a stack pointer or some other special register, return the
/// register class for the register. Otherwise, return null.
static const TargetRegisterClass *
isAllocatableRegister(unsigned Reg, MachineFunction &MF,
const TargetLowering &TLI, const MRegisterInfo *MRI) {
MVT::ValueType FoundVT = MVT::Other;
const TargetRegisterClass *FoundRC = 0;
for (MRegisterInfo::regclass_iterator RCI = MRI->regclass_begin(),
E = MRI->regclass_end(); RCI != E; ++RCI) {
MVT::ValueType ThisVT = MVT::Other;
const TargetRegisterClass *RC = *RCI;
// If none of the the value types for this register class are valid, we
// can't use it. For example, 64-bit reg classes on 32-bit targets.
for (TargetRegisterClass::vt_iterator I = RC->vt_begin(), E = RC->vt_end();
I != E; ++I) {
if (TLI.isTypeLegal(*I)) {
// If we have already found this register in a different register class,
// choose the one with the largest VT specified. For example, on
// PowerPC, we favor f64 register classes over f32.
if (FoundVT == MVT::Other ||
MVT::getSizeInBits(FoundVT) < MVT::getSizeInBits(*I)) {
ThisVT = *I;
break;
}
}
}
if (ThisVT == MVT::Other) continue;
// NOTE: This isn't ideal. In particular, this might allocate the
// frame pointer in functions that need it (due to them not being taken
// out of allocation, because a variable sized allocation hasn't been seen
// yet). This is a slight code pessimization, but should still work.
for (TargetRegisterClass::iterator I = RC->allocation_order_begin(MF),
E = RC->allocation_order_end(MF); I != E; ++I)
if (*I == Reg) {
// We found a matching register class. Keep looking at others in case
// we find one with larger registers that this physreg is also in.
FoundRC = RC;
FoundVT = ThisVT;
break;
}
}
return FoundRC;
}
RegsForValue SelectionDAGLowering::
GetRegistersForValue(const std::string &ConstrCode,
MVT::ValueType VT, bool isOutReg, bool isInReg,
std::set<unsigned> &OutputRegs,
std::set<unsigned> &InputRegs) {
std::pair<unsigned, const TargetRegisterClass*> PhysReg =
TLI.getRegForInlineAsmConstraint(ConstrCode, VT);
std::vector<unsigned> Regs;
unsigned NumRegs = VT != MVT::Other ? TLI.getNumElements(VT) : 1;
MVT::ValueType RegVT;
MVT::ValueType ValueVT = VT;
// If this is a constraint for a specific physical register, like {r17},
// assign it now.
if (PhysReg.first) {
if (VT == MVT::Other)
ValueVT = *PhysReg.second->vt_begin();
// Get the actual register value type. This is important, because the user
// may have asked for (e.g.) the AX register in i32 type. We need to
// remember that AX is actually i16 to get the right extension.
RegVT = *PhysReg.second->vt_begin();
// This is a explicit reference to a physical register.
Regs.push_back(PhysReg.first);
// If this is an expanded reference, add the rest of the regs to Regs.
if (NumRegs != 1) {
TargetRegisterClass::iterator I = PhysReg.second->begin();
TargetRegisterClass::iterator E = PhysReg.second->end();
for (; *I != PhysReg.first; ++I)
assert(I != E && "Didn't find reg!");
// Already added the first reg.
--NumRegs; ++I;
for (; NumRegs; --NumRegs, ++I) {
assert(I != E && "Ran out of registers to allocate!");
Regs.push_back(*I);
}
}
return RegsForValue(Regs, RegVT, ValueVT);
}
// Otherwise, if this was a reference to an LLVM register class, create vregs
// for this reference.
std::vector<unsigned> RegClassRegs;
if (PhysReg.second) {
// If this is an early clobber or tied register, our regalloc doesn't know
// how to maintain the constraint. If it isn't, go ahead and create vreg
// and let the regalloc do the right thing.
if (!isOutReg || !isInReg) {
if (VT == MVT::Other)
ValueVT = *PhysReg.second->vt_begin();
RegVT = *PhysReg.second->vt_begin();
// Create the appropriate number of virtual registers.
SSARegMap *RegMap = DAG.getMachineFunction().getSSARegMap();
for (; NumRegs; --NumRegs)
Regs.push_back(RegMap->createVirtualRegister(PhysReg.second));
return RegsForValue(Regs, RegVT, ValueVT);
}
// Otherwise, we can't allocate it. Let the code below figure out how to
// maintain these constraints.
RegClassRegs.assign(PhysReg.second->begin(), PhysReg.second->end());
} else {
// This is a reference to a register class that doesn't directly correspond
// to an LLVM register class. Allocate NumRegs consecutive, available,
// registers from the class.
RegClassRegs = TLI.getRegClassForInlineAsmConstraint(ConstrCode, VT);
}
const MRegisterInfo *MRI = DAG.getTarget().getRegisterInfo();
MachineFunction &MF = *CurMBB->getParent();
unsigned NumAllocated = 0;
for (unsigned i = 0, e = RegClassRegs.size(); i != e; ++i) {
unsigned Reg = RegClassRegs[i];
// See if this register is available.
if ((isOutReg && OutputRegs.count(Reg)) || // Already used.
(isInReg && InputRegs.count(Reg))) { // Already used.
// Make sure we find consecutive registers.
NumAllocated = 0;
continue;
}
// Check to see if this register is allocatable (i.e. don't give out the
// stack pointer).
const TargetRegisterClass *RC = isAllocatableRegister(Reg, MF, TLI, MRI);
if (!RC) {
// Make sure we find consecutive registers.
NumAllocated = 0;
continue;
}
// Okay, this register is good, we can use it.
++NumAllocated;
// If we allocated enough consecutive
if (NumAllocated == NumRegs) {
unsigned RegStart = (i-NumAllocated)+1;
unsigned RegEnd = i+1;
// Mark all of the allocated registers used.
for (unsigned i = RegStart; i != RegEnd; ++i) {
unsigned Reg = RegClassRegs[i];
Regs.push_back(Reg);
if (isOutReg) OutputRegs.insert(Reg); // Mark reg used.
if (isInReg) InputRegs.insert(Reg); // Mark reg used.
}
return RegsForValue(Regs, *RC->vt_begin(), VT);
}
}
// Otherwise, we couldn't allocate enough registers for this.
return RegsForValue();
}
/// getConstraintGenerality - Return an integer indicating how general CT is.
static 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;
}
}
static std::string GetMostGeneralConstraint(std::vector<std::string> &C,
const TargetLowering &TLI) {
assert(!C.empty() && "Must have at least one constraint");
if (C.size() == 1) return C[0];
std::string *Current = &C[0];
// 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.
TargetLowering::ConstraintType Flavor = TLI.getConstraintType(Current[0][0]);
for (unsigned j = 1, e = C.size(); j != e; ++j) {
TargetLowering::ConstraintType ThisFlavor = TLI.getConstraintType(C[j][0]);
if (getConstraintGenerality(ThisFlavor) >
getConstraintGenerality(Flavor)) {
// This constraint letter is more general than the previous one,
// use it.
Flavor = ThisFlavor;
Current = &C[j];
}
}
return *Current;
}
/// visitInlineAsm - Handle a call to an InlineAsm object.
///
void SelectionDAGLowering::visitInlineAsm(CallInst &I) {
InlineAsm *IA = cast<InlineAsm>(I.getOperand(0));
SDOperand AsmStr = DAG.getTargetExternalSymbol(IA->getAsmString().c_str(),
MVT::Other);
std::vector<InlineAsm::ConstraintInfo> Constraints = IA->ParseConstraints();
std::vector<MVT::ValueType> ConstraintVTs;
/// AsmNodeOperands - A list of pairs. The first element is a register, the
/// second is a bitfield where bit #0 is set if it is a use and bit #1 is set
/// if it is a def of that register.
std::vector<SDOperand> AsmNodeOperands;
AsmNodeOperands.push_back(SDOperand()); // reserve space for input chain
AsmNodeOperands.push_back(AsmStr);
SDOperand Chain = getRoot();
SDOperand Flag;
// We fully assign registers here at isel time. This is not optimal, but
// should work. For register classes that correspond to LLVM classes, we
// could let the LLVM RA do its thing, but we currently don't. Do a prepass
// over the constraints, collecting fixed registers that we know we can't use.
std::set<unsigned> OutputRegs, InputRegs;
unsigned OpNum = 1;
for (unsigned i = 0, e = Constraints.size(); i != e; ++i) {
std::string ConstraintCode =
GetMostGeneralConstraint(Constraints[i].Codes, TLI);
MVT::ValueType OpVT;
// Compute the value type for each operand and add it to ConstraintVTs.
switch (Constraints[i].Type) {
case InlineAsm::isOutput:
if (!Constraints[i].isIndirectOutput) {
assert(I.getType() != Type::VoidTy && "Bad inline asm!");
OpVT = TLI.getValueType(I.getType());
} else {
const Type *OpTy = I.getOperand(OpNum)->getType();
OpVT = TLI.getValueType(cast<PointerType>(OpTy)->getElementType());
OpNum++; // Consumes a call operand.
}
break;
case InlineAsm::isInput:
OpVT = TLI.getValueType(I.getOperand(OpNum)->getType());
OpNum++; // Consumes a call operand.
break;
case InlineAsm::isClobber:
OpVT = MVT::Other;
break;
}
ConstraintVTs.push_back(OpVT);
if (TLI.getRegForInlineAsmConstraint(ConstraintCode, OpVT).first == 0)
continue; // Not assigned a fixed reg.
// Build a list of regs that this operand uses. This always has a single
// element for promoted/expanded operands.
RegsForValue Regs = GetRegistersForValue(ConstraintCode, OpVT,
false, false,
OutputRegs, InputRegs);
switch (Constraints[i].Type) {
case InlineAsm::isOutput:
// We can't assign any other output to this register.
OutputRegs.insert(Regs.Regs.begin(), Regs.Regs.end());
// If this is an early-clobber output, it cannot be assigned to the same
// value as the input reg.
if (Constraints[i].isEarlyClobber || Constraints[i].hasMatchingInput)
InputRegs.insert(Regs.Regs.begin(), Regs.Regs.end());
break;
case InlineAsm::isInput:
// We can't assign any other input to this register.
InputRegs.insert(Regs.Regs.begin(), Regs.Regs.end());
break;
case InlineAsm::isClobber:
// Clobbered regs cannot be used as inputs or outputs.
InputRegs.insert(Regs.Regs.begin(), Regs.Regs.end());
OutputRegs.insert(Regs.Regs.begin(), Regs.Regs.end());
break;
}
}
// Loop over all of the inputs, copying the operand values into the
// appropriate registers and processing the output regs.
RegsForValue RetValRegs;
std::vector<std::pair<RegsForValue, Value*> > IndirectStoresToEmit;
OpNum = 1;
for (unsigned i = 0, e = Constraints.size(); i != e; ++i) {
std::string ConstraintCode =
GetMostGeneralConstraint(Constraints[i].Codes, TLI);
switch (Constraints[i].Type) {
case InlineAsm::isOutput: {
TargetLowering::ConstraintType CTy = TargetLowering::C_RegisterClass;
if (ConstraintCode.size() == 1) // not a physreg name.
CTy = TLI.getConstraintType(ConstraintCode[0]);
if (CTy == TargetLowering::C_Memory) {
// Memory output.
SDOperand InOperandVal = getValue(I.getOperand(OpNum));
// Check that the operand (the address to store to) isn't a float.
if (!MVT::isInteger(InOperandVal.getValueType()))
assert(0 && "MATCH FAIL!");
if (!Constraints[i].isIndirectOutput)
assert(0 && "MATCH FAIL!");
OpNum++; // Consumes a call operand.
// Extend/truncate to the right pointer type if needed.
MVT::ValueType PtrType = TLI.getPointerTy();
if (InOperandVal.getValueType() < PtrType)
InOperandVal = DAG.getNode(ISD::ZERO_EXTEND, PtrType, InOperandVal);
else if (InOperandVal.getValueType() > PtrType)
InOperandVal = DAG.getNode(ISD::TRUNCATE, PtrType, InOperandVal);
// Add information to the INLINEASM node to know about this output.
unsigned ResOpType = 4/*MEM*/ | (1 << 3);
AsmNodeOperands.push_back(DAG.getConstant(ResOpType, MVT::i32));
AsmNodeOperands.push_back(InOperandVal);
break;
}
// Otherwise, this is a register output.
assert(CTy == TargetLowering::C_RegisterClass && "Unknown op type!");
// If this is an early-clobber output, or if there is an input
// constraint that matches this, we need to reserve the input register
// so no other inputs allocate to it.
bool UsesInputRegister = false;
if (Constraints[i].isEarlyClobber || Constraints[i].hasMatchingInput)
UsesInputRegister = true;
// Copy the output from the appropriate register. Find a register that
// we can use.
RegsForValue Regs =
GetRegistersForValue(ConstraintCode, ConstraintVTs[i],
true, UsesInputRegister,
OutputRegs, InputRegs);
if (Regs.Regs.empty()) {
cerr << "Couldn't allocate output reg for contraint '"
<< ConstraintCode << "'!\n";
exit(1);
}
if (!Constraints[i].isIndirectOutput) {
assert(RetValRegs.Regs.empty() &&
"Cannot have multiple output constraints yet!");
assert(I.getType() != Type::VoidTy && "Bad inline asm!");
RetValRegs = Regs;
} else {
IndirectStoresToEmit.push_back(std::make_pair(Regs,
I.getOperand(OpNum)));
OpNum++; // Consumes a call operand.
}
// Add information to the INLINEASM node to know that this register is
// set.
Regs.AddInlineAsmOperands(2 /*REGDEF*/, DAG, AsmNodeOperands);
break;
}
case InlineAsm::isInput: {
SDOperand InOperandVal = getValue(I.getOperand(OpNum));
OpNum++; // Consumes a call operand.
if (isdigit(ConstraintCode[0])) { // Matching constraint?
// If this is required to match an output register we have already set,
// just use its register.
unsigned OperandNo = atoi(ConstraintCode.c_str());
// Scan until we find the definition we already emitted of this operand.
// When we find it, create a RegsForValue operand.
unsigned CurOp = 2; // The first operand.
for (; OperandNo; --OperandNo) {
// Advance to the next operand.
unsigned NumOps =
cast<ConstantSDNode>(AsmNodeOperands[CurOp])->getValue();
assert(((NumOps & 7) == 2 /*REGDEF*/ ||
(NumOps & 7) == 4 /*MEM*/) &&
"Skipped past definitions?");
CurOp += (NumOps>>3)+1;
}
unsigned NumOps =
cast<ConstantSDNode>(AsmNodeOperands[CurOp])->getValue();
if ((NumOps & 7) == 2 /*REGDEF*/) {
// Add NumOps>>3 registers to MatchedRegs.
RegsForValue MatchedRegs;
MatchedRegs.ValueVT = InOperandVal.getValueType();
MatchedRegs.RegVT = AsmNodeOperands[CurOp+1].getValueType();
for (unsigned i = 0, e = NumOps>>3; i != e; ++i) {
unsigned Reg =
cast<RegisterSDNode>(AsmNodeOperands[++CurOp])->getReg();
MatchedRegs.Regs.push_back(Reg);
}
// Use the produced MatchedRegs object to
MatchedRegs.getCopyToRegs(InOperandVal, DAG, Chain, Flag,
TLI.getPointerTy());
MatchedRegs.AddInlineAsmOperands(1 /*REGUSE*/, DAG, AsmNodeOperands);
break;
} else {
assert((NumOps & 7) == 4/*MEM*/ && "Unknown matching constraint!");
assert(0 && "matching constraints for memory operands unimp");
}
}
TargetLowering::ConstraintType CTy = TargetLowering::C_RegisterClass;
if (ConstraintCode.size() == 1) // not a physreg name.
CTy = TLI.getConstraintType(ConstraintCode[0]);
if (CTy == TargetLowering::C_Other) {
InOperandVal = TLI.isOperandValidForConstraint(InOperandVal,
ConstraintCode[0], DAG);
if (!InOperandVal.Val) {
cerr << "Invalid operand for inline asm constraint '"
<< ConstraintCode << "'!\n";
exit(1);
}
// Add information to the INLINEASM node to know about this input.
unsigned ResOpType = 3 /*IMM*/ | (1 << 3);
AsmNodeOperands.push_back(DAG.getConstant(ResOpType, MVT::i32));
AsmNodeOperands.push_back(InOperandVal);
break;
} else if (CTy == TargetLowering::C_Memory) {
// Memory input.
// Check that the operand isn't a float.
if (!MVT::isInteger(InOperandVal.getValueType()))
assert(0 && "MATCH FAIL!");
// Extend/truncate to the right pointer type if needed.
MVT::ValueType PtrType = TLI.getPointerTy();
if (InOperandVal.getValueType() < PtrType)
InOperandVal = DAG.getNode(ISD::ZERO_EXTEND, PtrType, InOperandVal);
else if (InOperandVal.getValueType() > PtrType)
InOperandVal = DAG.getNode(ISD::TRUNCATE, PtrType, InOperandVal);
// Add information to the INLINEASM node to know about this input.
unsigned ResOpType = 4/*MEM*/ | (1 << 3);
AsmNodeOperands.push_back(DAG.getConstant(ResOpType, MVT::i32));
AsmNodeOperands.push_back(InOperandVal);
break;
}
assert(CTy == TargetLowering::C_RegisterClass && "Unknown op type!");
// Copy the input into the appropriate registers.
RegsForValue InRegs =
GetRegistersForValue(ConstraintCode, ConstraintVTs[i],
false, true, OutputRegs, InputRegs);
// FIXME: should be match fail.
assert(!InRegs.Regs.empty() && "Couldn't allocate input reg!");
InRegs.getCopyToRegs(InOperandVal, DAG, Chain, Flag, TLI.getPointerTy());
InRegs.AddInlineAsmOperands(1/*REGUSE*/, DAG, AsmNodeOperands);
break;
}
case InlineAsm::isClobber: {
RegsForValue ClobberedRegs =
GetRegistersForValue(ConstraintCode, MVT::Other, false, false,
OutputRegs, InputRegs);
// Add the clobbered value to the operand list, so that the register
// allocator is aware that the physreg got clobbered.
if (!ClobberedRegs.Regs.empty())
ClobberedRegs.AddInlineAsmOperands(2/*REGDEF*/, DAG, AsmNodeOperands);
break;
}
}
}
// Finish up input operands.
AsmNodeOperands[0] = Chain;
if (Flag.Val) AsmNodeOperands.push_back(Flag);
Chain = DAG.getNode(ISD::INLINEASM,
DAG.getNodeValueTypes(MVT::Other, MVT::Flag), 2,
&AsmNodeOperands[0], AsmNodeOperands.size());
Flag = Chain.getValue(1);
// If this asm returns a register value, copy the result from that register
// and set it as the value of the call.
if (!RetValRegs.Regs.empty())
setValue(&I, RetValRegs.getCopyFromRegs(DAG, Chain, Flag));
std::vector<std::pair<SDOperand, Value*> > StoresToEmit;
// Process indirect outputs, first output all of the flagged copies out of
// physregs.
for (unsigned i = 0, e = IndirectStoresToEmit.size(); i != e; ++i) {
RegsForValue &OutRegs = IndirectStoresToEmit[i].first;
Value *Ptr = IndirectStoresToEmit[i].second;
SDOperand OutVal = OutRegs.getCopyFromRegs(DAG, Chain, Flag);
StoresToEmit.push_back(std::make_pair(OutVal, Ptr));
}
// Emit the non-flagged stores from the physregs.
SmallVector<SDOperand, 8> OutChains;
for (unsigned i = 0, e = StoresToEmit.size(); i != e; ++i)
OutChains.push_back(DAG.getStore(Chain, StoresToEmit[i].first,
getValue(StoresToEmit[i].second),
StoresToEmit[i].second, 0));
if (!OutChains.empty())
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other,
&OutChains[0], OutChains.size());
DAG.setRoot(Chain);
}
void SelectionDAGLowering::visitMalloc(MallocInst &I) {
SDOperand Src = getValue(I.getOperand(0));
MVT::ValueType IntPtr = TLI.getPointerTy();
if (IntPtr < Src.getValueType())
Src = DAG.getNode(ISD::TRUNCATE, IntPtr, Src);
else if (IntPtr > Src.getValueType())
Src = DAG.getNode(ISD::ZERO_EXTEND, IntPtr, Src);
// Scale the source by the type size.
uint64_t ElementSize = TD->getTypeSize(I.getType()->getElementType());
Src = DAG.getNode(ISD::MUL, Src.getValueType(),
Src, getIntPtrConstant(ElementSize));
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
Entry.Node = Src;
Entry.Ty = TLI.getTargetData()->getIntPtrType();
Entry.isSigned = false;
Entry.isInReg = false;
Entry.isSRet = false;
Args.push_back(Entry);
std::pair<SDOperand,SDOperand> Result =
TLI.LowerCallTo(getRoot(), I.getType(), false, false, CallingConv::C, true,
DAG.getExternalSymbol("malloc", IntPtr),
Args, DAG);
setValue(&I, Result.first); // Pointers always fit in registers
DAG.setRoot(Result.second);
}
void SelectionDAGLowering::visitFree(FreeInst &I) {
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
Entry.Node = getValue(I.getOperand(0));
Entry.Ty = TLI.getTargetData()->getIntPtrType();
Entry.isSigned = false;
Entry.isInReg = false;
Entry.isSRet = false;
Args.push_back(Entry);
MVT::ValueType IntPtr = TLI.getPointerTy();
std::pair<SDOperand,SDOperand> Result =
TLI.LowerCallTo(getRoot(), Type::VoidTy, false, false, CallingConv::C, true,
DAG.getExternalSymbol("free", IntPtr), Args, DAG);
DAG.setRoot(Result.second);
}
// InsertAtEndOfBasicBlock - 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.
MachineBasicBlock *TargetLowering::InsertAtEndOfBasicBlock(MachineInstr *MI,
MachineBasicBlock *MBB) {
cerr << "If a target marks an instruction with "
<< "'usesCustomDAGSchedInserter', it must implement "
<< "TargetLowering::InsertAtEndOfBasicBlock!\n";
abort();
return 0;
}
void SelectionDAGLowering::visitVAStart(CallInst &I) {
DAG.setRoot(DAG.getNode(ISD::VASTART, MVT::Other, getRoot(),
getValue(I.getOperand(1)),
DAG.getSrcValue(I.getOperand(1))));
}
void SelectionDAGLowering::visitVAArg(VAArgInst &I) {
SDOperand V = DAG.getVAArg(TLI.getValueType(I.getType()), getRoot(),
getValue(I.getOperand(0)),
DAG.getSrcValue(I.getOperand(0)));
setValue(&I, V);
DAG.setRoot(V.getValue(1));
}
void SelectionDAGLowering::visitVAEnd(CallInst &I) {
DAG.setRoot(DAG.getNode(ISD::VAEND, MVT::Other, getRoot(),
getValue(I.getOperand(1)),
DAG.getSrcValue(I.getOperand(1))));
}
void SelectionDAGLowering::visitVACopy(CallInst &I) {
DAG.setRoot(DAG.getNode(ISD::VACOPY, MVT::Other, getRoot(),
getValue(I.getOperand(1)),
getValue(I.getOperand(2)),
DAG.getSrcValue(I.getOperand(1)),
DAG.getSrcValue(I.getOperand(2))));
}
/// ExpandScalarFormalArgs - Recursively expand the formal_argument node, either
/// bit_convert it or join a pair of them with a BUILD_PAIR when appropriate.
static SDOperand ExpandScalarFormalArgs(MVT::ValueType VT, SDNode *Arg,
unsigned &i, SelectionDAG &DAG,
TargetLowering &TLI) {
if (TLI.getTypeAction(VT) != TargetLowering::Expand)
return SDOperand(Arg, i++);
MVT::ValueType EVT = TLI.getTypeToTransformTo(VT);
unsigned NumVals = MVT::getSizeInBits(VT) / MVT::getSizeInBits(EVT);
if (NumVals == 1) {
return DAG.getNode(ISD::BIT_CONVERT, VT,
ExpandScalarFormalArgs(EVT, Arg, i, DAG, TLI));
} else if (NumVals == 2) {
SDOperand Lo = ExpandScalarFormalArgs(EVT, Arg, i, DAG, TLI);
SDOperand Hi = ExpandScalarFormalArgs(EVT, Arg, i, DAG, TLI);
if (!TLI.isLittleEndian())
std::swap(Lo, Hi);
return DAG.getNode(ISD::BUILD_PAIR, VT, Lo, Hi);
} else {
// Value scalarized into many values. Unimp for now.
assert(0 && "Cannot expand i64 -> i16 yet!");
}
return SDOperand();
}
/// TargetLowering::LowerArguments - This is the default LowerArguments
/// implementation, which just inserts a FORMAL_ARGUMENTS node. FIXME: When all
/// targets are migrated to using FORMAL_ARGUMENTS, this hook should be
/// integrated into SDISel.
std::vector<SDOperand>
TargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) {
const FunctionType *FTy = F.getFunctionType();
// Add CC# and isVararg as operands to the FORMAL_ARGUMENTS node.
std::vector<SDOperand> Ops;
Ops.push_back(DAG.getRoot());
Ops.push_back(DAG.getConstant(F.getCallingConv(), getPointerTy()));
Ops.push_back(DAG.getConstant(F.isVarArg(), getPointerTy()));
// Add one result value for each formal argument.
std::vector<MVT::ValueType> RetVals;
unsigned j = 1;
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end();
I != E; ++I, ++j) {
MVT::ValueType VT = getValueType(I->getType());
bool isInReg = FTy->paramHasAttr(j, FunctionType::InRegAttribute);
bool isSRet = FTy->paramHasAttr(j, FunctionType::StructRetAttribute);
unsigned OriginalAlignment =
getTargetData()->getABITypeAlignment(I->getType());
// Flags[31:27] -> OriginalAlignment
// Flags[2] -> isSRet
// Flags[1] -> isInReg
unsigned Flags = (isInReg << 1) | (isSRet << 2) | (OriginalAlignment << 27);
switch (getTypeAction(VT)) {
default: assert(0 && "Unknown type action!");
case Legal:
RetVals.push_back(VT);
Ops.push_back(DAG.getConstant(Flags, MVT::i32));
break;
case Promote:
RetVals.push_back(getTypeToTransformTo(VT));
Ops.push_back(DAG.getConstant(Flags, MVT::i32));
break;
case Expand:
if (VT != MVT::Vector) {
// If this is a large integer, it needs to be broken up into small
// integers. Figure out what the destination type is and how many small
// integers it turns into.
MVT::ValueType NVT = getTypeToExpandTo(VT);
unsigned NumVals = getNumElements(VT);
for (unsigned i = 0; i != NumVals; ++i) {
RetVals.push_back(NVT);
// if it isn't first piece, alignment must be 1
if (i == 1) Flags = (Flags & 0x07ffffff) | (1 << 27);
Ops.push_back(DAG.getConstant(Flags, MVT::i32));
}
} else {
// Otherwise, this is a vector type. We only support legal vectors
// right now.
unsigned NumElems = cast<VectorType>(I->getType())->getNumElements();
const Type *EltTy = cast<VectorType>(I->getType())->getElementType();
// Figure out if there is a Packed type corresponding to this Vector
// type. If so, convert to the vector type.
MVT::ValueType TVT = MVT::getVectorType(getValueType(EltTy), NumElems);
if (TVT != MVT::Other && isTypeLegal(TVT)) {
RetVals.push_back(TVT);
Ops.push_back(DAG.getConstant(Flags, MVT::i32));
} else {
assert(0 && "Don't support illegal by-val vector arguments yet!");
}
}
break;
}
}
RetVals.push_back(MVT::Other);
// Create the node.
SDNode *Result = DAG.getNode(ISD::FORMAL_ARGUMENTS,
DAG.getNodeValueTypes(RetVals), RetVals.size(),
&Ops[0], Ops.size()).Val;
DAG.setRoot(SDOperand(Result, Result->getNumValues()-1));
// Set up the return result vector.
Ops.clear();
unsigned i = 0;
unsigned Idx = 1;
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E;
++I, ++Idx) {
MVT::ValueType VT = getValueType(I->getType());
switch (getTypeAction(VT)) {
default: assert(0 && "Unknown type action!");
case Legal:
Ops.push_back(SDOperand(Result, i++));
break;
case Promote: {
SDOperand Op(Result, i++);
if (MVT::isInteger(VT)) {
if (FTy->paramHasAttr(Idx, FunctionType::SExtAttribute))
Op = DAG.getNode(ISD::AssertSext, Op.getValueType(), Op,
DAG.getValueType(VT));
else if (FTy->paramHasAttr(Idx, FunctionType::ZExtAttribute))
Op = DAG.getNode(ISD::AssertZext, Op.getValueType(), Op,
DAG.getValueType(VT));
Op = DAG.getNode(ISD::TRUNCATE, VT, Op);
} else {
assert(MVT::isFloatingPoint(VT) && "Not int or FP?");
Op = DAG.getNode(ISD::FP_ROUND, VT, Op);
}
Ops.push_back(Op);
break;
}
case Expand:
if (VT != MVT::Vector) {
// If this is a large integer or a floating point node that needs to be
// expanded, it needs to be reassembled from small integers. Figure out
// what the source elt type is and how many small integers it is.
Ops.push_back(ExpandScalarFormalArgs(VT, Result, i, DAG, *this));
} else {
// Otherwise, this is a vector type. We only support legal vectors
// right now.
const VectorType *PTy = cast<VectorType>(I->getType());
unsigned NumElems = PTy->getNumElements();
const Type *EltTy = PTy->getElementType();
// Figure out if there is a Packed type corresponding to this Vector
// type. If so, convert to the vector type.
MVT::ValueType TVT = MVT::getVectorType(getValueType(EltTy), NumElems);
if (TVT != MVT::Other && isTypeLegal(TVT)) {
SDOperand N = SDOperand(Result, i++);
// Handle copies from generic vectors to registers.
N = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, N,
DAG.getConstant(NumElems, MVT::i32),
DAG.getValueType(getValueType(EltTy)));
Ops.push_back(N);
} else {
assert(0 && "Don't support illegal by-val vector arguments yet!");
abort();
}
}
break;
}
}
return Ops;
}
/// ExpandScalarCallArgs - Recursively expand call argument node by
/// bit_converting it or extract a pair of elements from the larger node.
static void ExpandScalarCallArgs(MVT::ValueType VT, SDOperand Arg,
unsigned Flags,
SmallVector<SDOperand, 32> &Ops,
SelectionDAG &DAG,
TargetLowering &TLI,
bool isFirst = true) {
if (TLI.getTypeAction(VT) != TargetLowering::Expand) {
// if it isn't first piece, alignment must be 1
if (!isFirst)
Flags = (Flags & 0x07ffffff) | (1 << 27);
Ops.push_back(Arg);
Ops.push_back(DAG.getConstant(Flags, MVT::i32));
return;
}
MVT::ValueType EVT = TLI.getTypeToTransformTo(VT);
unsigned NumVals = MVT::getSizeInBits(VT) / MVT::getSizeInBits(EVT);
if (NumVals == 1) {
Arg = DAG.getNode(ISD::BIT_CONVERT, EVT, Arg);
ExpandScalarCallArgs(EVT, Arg, Flags, Ops, DAG, TLI, isFirst);
} else if (NumVals == 2) {
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, EVT, Arg,
DAG.getConstant(0, TLI.getPointerTy()));
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, EVT, Arg,
DAG.getConstant(1, TLI.getPointerTy()));
if (!TLI.isLittleEndian())
std::swap(Lo, Hi);
ExpandScalarCallArgs(EVT, Lo, Flags, Ops, DAG, TLI, isFirst);
ExpandScalarCallArgs(EVT, Hi, Flags, Ops, DAG, TLI, false);
} else {
// Value scalarized into many values. Unimp for now.
assert(0 && "Cannot expand i64 -> i16 yet!");
}
}
/// TargetLowering::LowerCallTo - This is the default LowerCallTo
/// implementation, which just inserts an ISD::CALL node, which is later custom
/// lowered by the target to something concrete. FIXME: When all targets are
/// migrated to using ISD::CALL, this hook should be integrated into SDISel.
std::pair<SDOperand, SDOperand>
TargetLowering::LowerCallTo(SDOperand Chain, const Type *RetTy,
bool RetTyIsSigned, bool isVarArg,
unsigned CallingConv, bool isTailCall,
SDOperand Callee,
ArgListTy &Args, SelectionDAG &DAG) {
SmallVector<SDOperand, 32> Ops;
Ops.push_back(Chain); // Op#0 - Chain
Ops.push_back(DAG.getConstant(CallingConv, getPointerTy())); // Op#1 - CC
Ops.push_back(DAG.getConstant(isVarArg, getPointerTy())); // Op#2 - VarArg
Ops.push_back(DAG.getConstant(isTailCall, getPointerTy())); // Op#3 - Tail
Ops.push_back(Callee);
// Handle all of the outgoing arguments.
for (unsigned i = 0, e = Args.size(); i != e; ++i) {
MVT::ValueType VT = getValueType(Args[i].Ty);
SDOperand Op = Args[i].Node;
bool isSigned = Args[i].isSigned;
bool isInReg = Args[i].isInReg;
bool isSRet = Args[i].isSRet;
unsigned OriginalAlignment =
getTargetData()->getABITypeAlignment(Args[i].Ty);
// Flags[31:27] -> OriginalAlignment
// Flags[2] -> isSRet
// Flags[1] -> isInReg
// Flags[0] -> isSigned
unsigned Flags = (isSRet << 2) | (isInReg << 1) | isSigned |
(OriginalAlignment << 27);
switch (getTypeAction(VT)) {
default: assert(0 && "Unknown type action!");
case Legal:
Ops.push_back(Op);
Ops.push_back(DAG.getConstant(Flags, MVT::i32));
break;
case Promote:
if (MVT::isInteger(VT)) {
unsigned ExtOp = isSigned ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
Op = DAG.getNode(ExtOp, getTypeToTransformTo(VT), Op);
} else {
assert(MVT::isFloatingPoint(VT) && "Not int or FP?");
Op = DAG.getNode(ISD::FP_EXTEND, getTypeToTransformTo(VT), Op);
}
Ops.push_back(Op);
Ops.push_back(DAG.getConstant(Flags, MVT::i32));
break;
case Expand:
if (VT != MVT::Vector) {
// If this is a large integer, it needs to be broken down into small
// integers. Figure out what the source elt type is and how many small
// integers it is.
ExpandScalarCallArgs(VT, Op, Flags, Ops, DAG, *this);
} else {
// Otherwise, this is a vector type. We only support legal vectors
// right now.
const VectorType *PTy = cast<VectorType>(Args[i].Ty);
unsigned NumElems = PTy->getNumElements();
const Type *EltTy = PTy->getElementType();
// Figure out if there is a Packed type corresponding to this Vector
// type. If so, convert to the vector type.
MVT::ValueType TVT = MVT::getVectorType(getValueType(EltTy), NumElems);
if (TVT != MVT::Other && isTypeLegal(TVT)) {
// Insert a VBIT_CONVERT of the MVT::Vector type to the vector type.
Op = DAG.getNode(ISD::VBIT_CONVERT, TVT, Op);
Ops.push_back(Op);
Ops.push_back(DAG.getConstant(Flags, MVT::i32));
} else {
assert(0 && "Don't support illegal by-val vector call args yet!");
abort();
}
}
break;
}
}
// Figure out the result value types.
SmallVector<MVT::ValueType, 4> RetTys;
if (RetTy != Type::VoidTy) {
MVT::ValueType VT = getValueType(RetTy);
switch (getTypeAction(VT)) {
default: assert(0 && "Unknown type action!");
case Legal:
RetTys.push_back(VT);
break;
case Promote:
RetTys.push_back(getTypeToTransformTo(VT));
break;
case Expand:
if (VT != MVT::Vector) {
// If this is a large integer, it needs to be reassembled from small
// integers. Figure out what the source elt type is and how many small
// integers it is.
MVT::ValueType NVT = getTypeToExpandTo(VT);
unsigned NumVals = getNumElements(VT);
for (unsigned i = 0; i != NumVals; ++i)
RetTys.push_back(NVT);
} else {
// Otherwise, this is a vector type. We only support legal vectors
// right now.
const VectorType *PTy = cast<VectorType>(RetTy);
unsigned NumElems = PTy->getNumElements();
const Type *EltTy = PTy->getElementType();
// Figure out if there is a Packed type corresponding to this Vector
// type. If so, convert to the vector type.
MVT::ValueType TVT = MVT::getVectorType(getValueType(EltTy), NumElems);
if (TVT != MVT::Other && isTypeLegal(TVT)) {
RetTys.push_back(TVT);
} else {
assert(0 && "Don't support illegal by-val vector call results yet!");
abort();
}
}
}
}
RetTys.push_back(MVT::Other); // Always has a chain.
// Finally, create the CALL node.
SDOperand Res = DAG.getNode(ISD::CALL,
DAG.getVTList(&RetTys[0], RetTys.size()),
&Ops[0], Ops.size());
// 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.
SDOperand ResVal;
if (RetTys.size() != 1) {
MVT::ValueType VT = getValueType(RetTy);
if (RetTys.size() == 2) {
ResVal = Res;
// If this value was promoted, truncate it down.
if (ResVal.getValueType() != VT) {
if (VT == MVT::Vector) {
// Insert a VBITCONVERT to convert from the packed result type to the
// MVT::Vector type.
unsigned NumElems = cast<VectorType>(RetTy)->getNumElements();
const Type *EltTy = cast<VectorType>(RetTy)->getElementType();
// Figure out if there is a Packed type corresponding to this Vector
// type. If so, convert to the vector type.
MVT::ValueType TVT = MVT::getVectorType(getValueType(EltTy),NumElems);
if (TVT != MVT::Other && isTypeLegal(TVT)) {
// Insert a VBIT_CONVERT of the FORMAL_ARGUMENTS to a
// "N x PTyElementVT" MVT::Vector type.
ResVal = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, ResVal,
DAG.getConstant(NumElems, MVT::i32),
DAG.getValueType(getValueType(EltTy)));
} else {
abort();
}
} else if (MVT::isInteger(VT)) {
unsigned AssertOp = ISD::AssertSext;
if (!RetTyIsSigned)
AssertOp = ISD::AssertZext;
ResVal = DAG.getNode(AssertOp, ResVal.getValueType(), ResVal,
DAG.getValueType(VT));
ResVal = DAG.getNode(ISD::TRUNCATE, VT, ResVal);
} else {
assert(MVT::isFloatingPoint(VT));
if (getTypeAction(VT) == Expand)
ResVal = DAG.getNode(ISD::BIT_CONVERT, VT, ResVal);
else
ResVal = DAG.getNode(ISD::FP_ROUND, VT, ResVal);
}
}
} else if (RetTys.size() == 3) {
ResVal = DAG.getNode(ISD::BUILD_PAIR, VT,
Res.getValue(0), Res.getValue(1));
} else {
assert(0 && "Case not handled yet!");
}
}
return std::make_pair(ResVal, Res.getValue(Res.Val->getNumValues()-1));
}
SDOperand TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
assert(0 && "LowerOperation not implemented for this target!");
abort();
return SDOperand();
}
SDOperand TargetLowering::CustomPromoteOperation(SDOperand Op,
SelectionDAG &DAG) {
assert(0 && "CustomPromoteOperation not implemented for this target!");
abort();
return SDOperand();
}
/// getMemsetValue - Vectorized representation of the memset value
/// operand.
static SDOperand getMemsetValue(SDOperand Value, MVT::ValueType VT,
SelectionDAG &DAG) {
MVT::ValueType CurVT = VT;
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Value)) {
uint64_t Val = C->getValue() & 255;
unsigned Shift = 8;
while (CurVT != MVT::i8) {
Val = (Val << Shift) | Val;
Shift <<= 1;
CurVT = (MVT::ValueType)((unsigned)CurVT - 1);
}
return DAG.getConstant(Val, VT);
} else {
Value = DAG.getNode(ISD::ZERO_EXTEND, VT, Value);
unsigned Shift = 8;
while (CurVT != MVT::i8) {
Value =
DAG.getNode(ISD::OR, VT,
DAG.getNode(ISD::SHL, VT, Value,
DAG.getConstant(Shift, MVT::i8)), Value);
Shift <<= 1;
CurVT = (MVT::ValueType)((unsigned)CurVT - 1);
}
return Value;
}
}
/// getMemsetStringVal - Similar to getMemsetValue. Except this is only
/// used when a memcpy is turned into a memset when the source is a constant
/// string ptr.
static SDOperand getMemsetStringVal(MVT::ValueType VT,
SelectionDAG &DAG, TargetLowering &TLI,
std::string &Str, unsigned Offset) {
uint64_t Val = 0;
unsigned MSB = getSizeInBits(VT) / 8;
if (TLI.isLittleEndian())
Offset = Offset + MSB - 1;
for (unsigned i = 0; i != MSB; ++i) {
Val = (Val << 8) | (unsigned char)Str[Offset];
Offset += TLI.isLittleEndian() ? -1 : 1;
}
return DAG.getConstant(Val, VT);
}
/// getMemBasePlusOffset - Returns base and offset node for the
static SDOperand getMemBasePlusOffset(SDOperand Base, unsigned Offset,
SelectionDAG &DAG, TargetLowering &TLI) {
MVT::ValueType VT = Base.getValueType();
return DAG.getNode(ISD::ADD, VT, Base, DAG.getConstant(Offset, VT));
}
/// MeetsMaxMemopRequirement - Determines if the number of memory ops required
/// to replace the memset / memcpy is below the threshold. It also returns the
/// types of the sequence of memory ops to perform memset / memcpy.
static bool MeetsMaxMemopRequirement(std::vector<MVT::ValueType> &MemOps,
unsigned Limit, uint64_t Size,
unsigned Align, TargetLowering &TLI) {
MVT::ValueType VT;
if (TLI.allowsUnalignedMemoryAccesses()) {
VT = MVT::i64;
} else {
switch (Align & 7) {
case 0:
VT = MVT::i64;
break;
case 4:
VT = MVT::i32;
break;
case 2:
VT = MVT::i16;
break;
default:
VT = MVT::i8;
break;
}
}
MVT::ValueType LVT = MVT::i64;
while (!TLI.isTypeLegal(LVT))
LVT = (MVT::ValueType)((unsigned)LVT - 1);
assert(MVT::isInteger(LVT));
if (VT > LVT)
VT = LVT;
unsigned NumMemOps = 0;
while (Size != 0) {
unsigned VTSize = getSizeInBits(VT) / 8;
while (VTSize > Size) {
VT = (MVT::ValueType)((unsigned)VT - 1);
VTSize >>= 1;
}
assert(MVT::isInteger(VT));
if (++NumMemOps > Limit)
return false;
MemOps.push_back(VT);
Size -= VTSize;
}
return true;
}
void SelectionDAGLowering::visitMemIntrinsic(CallInst &I, unsigned Op) {
SDOperand Op1 = getValue(I.getOperand(1));
SDOperand Op2 = getValue(I.getOperand(2));
SDOperand Op3 = getValue(I.getOperand(3));
SDOperand Op4 = getValue(I.getOperand(4));
unsigned Align = (unsigned)cast<ConstantSDNode>(Op4)->getValue();
if (Align == 0) Align = 1;
if (ConstantSDNode *Size = dyn_cast<ConstantSDNode>(Op3)) {
std::vector<MVT::ValueType> MemOps;
// Expand memset / memcpy to a series of load / store ops
// if the size operand falls below a certain threshold.
SmallVector<SDOperand, 8> OutChains;
switch (Op) {
default: break; // Do nothing for now.
case ISD::MEMSET: {
if (MeetsMaxMemopRequirement(MemOps, TLI.getMaxStoresPerMemset(),
Size->getValue(), Align, TLI)) {
unsigned NumMemOps = MemOps.size();
unsigned Offset = 0;
for (unsigned i = 0; i < NumMemOps; i++) {
MVT::ValueType VT = MemOps[i];
unsigned VTSize = getSizeInBits(VT) / 8;
SDOperand Value = getMemsetValue(Op2, VT, DAG);
SDOperand Store = DAG.getStore(getRoot(), Value,
getMemBasePlusOffset(Op1, Offset, DAG, TLI),
I.getOperand(1), Offset);
OutChains.push_back(Store);
Offset += VTSize;
}
}
break;
}
case ISD::MEMCPY: {
if (MeetsMaxMemopRequirement(MemOps, TLI.getMaxStoresPerMemcpy(),
Size->getValue(), Align, TLI)) {
unsigned NumMemOps = MemOps.size();
unsigned SrcOff = 0, DstOff = 0, SrcDelta = 0;
GlobalAddressSDNode *G = NULL;
std::string Str;
bool CopyFromStr = false;
if (Op2.getOpcode() == ISD::GlobalAddress)
G = cast<GlobalAddressSDNode>(Op2);
else if (Op2.getOpcode() == ISD::ADD &&
Op2.getOperand(0).getOpcode() == ISD::GlobalAddress &&
Op2.getOperand(1).getOpcode() == ISD::Constant) {
G = cast<GlobalAddressSDNode>(Op2.getOperand(0));
SrcDelta = cast<ConstantSDNode>(Op2.getOperand(1))->getValue();
}
if (G) {
GlobalVariable *GV = dyn_cast<GlobalVariable>(G->getGlobal());
if (GV && GV->isConstant()) {
Str = GV->getStringValue(false);
if (!Str.empty()) {
CopyFromStr = true;
SrcOff += SrcDelta;
}
}
}
for (unsigned i = 0; i < NumMemOps; i++) {
MVT::ValueType VT = MemOps[i];
unsigned VTSize = getSizeInBits(VT) / 8;
SDOperand Value, Chain, Store;
if (CopyFromStr) {
Value = getMemsetStringVal(VT, DAG, TLI, Str, SrcOff);
Chain = getRoot();
Store =
DAG.getStore(Chain, Value,
getMemBasePlusOffset(Op1, DstOff, DAG, TLI),
I.getOperand(1), DstOff);
} else {
Value = DAG.getLoad(VT, getRoot(),
getMemBasePlusOffset(Op2, SrcOff, DAG, TLI),
I.getOperand(2), SrcOff);
Chain = Value.getValue(1);
Store =
DAG.getStore(Chain, Value,
getMemBasePlusOffset(Op1, DstOff, DAG, TLI),
I.getOperand(1), DstOff);
}
OutChains.push_back(Store);
SrcOff += VTSize;
DstOff += VTSize;
}
}
break;
}
}
if (!OutChains.empty()) {
DAG.setRoot(DAG.getNode(ISD::TokenFactor, MVT::Other,
&OutChains[0], OutChains.size()));
return;
}
}
DAG.setRoot(DAG.getNode(Op, MVT::Other, getRoot(), Op1, Op2, Op3, Op4));
}
//===----------------------------------------------------------------------===//
// SelectionDAGISel code
//===----------------------------------------------------------------------===//
unsigned SelectionDAGISel::MakeReg(MVT::ValueType VT) {
return RegMap->createVirtualRegister(TLI.getRegClassFor(VT));
}
void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const {
// FIXME: we only modify the CFG to split critical edges. This
// updates dom and loop info.
AU.addRequired<AliasAnalysis>();
}
/// OptimizeNoopCopyExpression - We have determined that the specified cast
/// instruction is a noop copy (e.g. it's casting from one pointer type to
/// another, int->uint, or int->sbyte on PPC.
///
/// Return true if any changes are made.
static bool OptimizeNoopCopyExpression(CastInst *CI) {
BasicBlock *DefBB = CI->getParent();
/// InsertedCasts - Only insert a cast in each block once.
std::map<BasicBlock*, CastInst*> InsertedCasts;
bool MadeChange = false;
for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
UI != E; ) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
// Figure out which BB this cast is used in. For PHI's this is the
// appropriate predecessor block.
BasicBlock *UserBB = User->getParent();
if (PHINode *PN = dyn_cast<PHINode>(User)) {
unsigned OpVal = UI.getOperandNo()/2;
UserBB = PN->getIncomingBlock(OpVal);
}
// Preincrement use iterator so we don't invalidate it.
++UI;
// If this user is in the same block as the cast, don't change the cast.
if (UserBB == DefBB) continue;
// If we have already inserted a cast into this block, use it.
CastInst *&InsertedCast = InsertedCasts[UserBB];
if (!InsertedCast) {
BasicBlock::iterator InsertPt = UserBB->begin();
while (isa<PHINode>(InsertPt)) ++InsertPt;
InsertedCast =
CastInst::create(CI->getOpcode(), CI->getOperand(0), CI->getType(), "",
InsertPt);
MadeChange = true;
}
// Replace a use of the cast with a use of the new casat.
TheUse = InsertedCast;
}
// If we removed all uses, nuke the cast.
if (CI->use_empty())
CI->eraseFromParent();
return MadeChange;
}
/// InsertGEPComputeCode - Insert code into BB to compute Ptr+PtrOffset,
/// casting to the type of GEPI.
static Instruction *InsertGEPComputeCode(Instruction *&V, BasicBlock *BB,
Instruction *GEPI, Value *Ptr,
Value *PtrOffset) {
if (V) return V; // Already computed.
// Figure out the insertion point
BasicBlock::iterator InsertPt;
if (BB == GEPI->getParent()) {
// If GEP is already inserted into BB, insert right after the GEP.
InsertPt = GEPI;
++InsertPt;
} else {
// Otherwise, insert at the top of BB, after any PHI nodes
InsertPt = BB->begin();
while (isa<PHINode>(InsertPt)) ++InsertPt;
}
// If Ptr is itself a cast, but in some other BB, emit a copy of the cast into
// BB so that there is only one value live across basic blocks (the cast
// operand).
if (CastInst *CI = dyn_cast<CastInst>(Ptr))
if (CI->getParent() != BB && isa<PointerType>(CI->getOperand(0)->getType()))
Ptr = CastInst::create(CI->getOpcode(), CI->getOperand(0), CI->getType(),
"", InsertPt);
// Add the offset, cast it to the right type.
Ptr = BinaryOperator::createAdd(Ptr, PtrOffset, "", InsertPt);
// Ptr is an integer type, GEPI is pointer type ==> IntToPtr
return V = CastInst::create(Instruction::IntToPtr, Ptr, GEPI->getType(),
"", InsertPt);
}
/// ReplaceUsesOfGEPInst - Replace all uses of RepPtr with inserted code to
/// compute its value. The RepPtr value can be computed with Ptr+PtrOffset. One
/// trivial way of doing this would be to evaluate Ptr+PtrOffset in RepPtr's
/// block, then ReplaceAllUsesWith'ing everything. However, we would prefer to
/// sink PtrOffset into user blocks where doing so will likely allow us to fold
/// the constant add into a load or store instruction. Additionally, if a user
/// is a pointer-pointer cast, we look through it to find its users.
static void ReplaceUsesOfGEPInst(Instruction *RepPtr, Value *Ptr,
Constant *PtrOffset, BasicBlock *DefBB,
GetElementPtrInst *GEPI,
std::map<BasicBlock*,Instruction*> &InsertedExprs) {
while (!RepPtr->use_empty()) {
Instruction *User = cast<Instruction>(RepPtr->use_back());
// If the user is a Pointer-Pointer cast, recurse. Only BitCast can be
// used for a Pointer-Pointer cast.
if (isa<BitCastInst>(User)) {
ReplaceUsesOfGEPInst(User, Ptr, PtrOffset, DefBB, GEPI, InsertedExprs);
// Drop the use of RepPtr. The cast is dead. Don't delete it now, else we
// could invalidate an iterator.
User->setOperand(0, UndefValue::get(RepPtr->getType()));
continue;
}
// If this is a load of the pointer, or a store through the pointer, emit
// the increment into the load/store block.
Instruction *NewVal;
if (isa<LoadInst>(User) ||
(isa<StoreInst>(User) && User->getOperand(0) != RepPtr)) {
NewVal = InsertGEPComputeCode(InsertedExprs[User->getParent()],
User->getParent(), GEPI,
Ptr, PtrOffset);
} else {
// If this use is not foldable into the addressing mode, use a version
// emitted in the GEP block.
NewVal = InsertGEPComputeCode(InsertedExprs[DefBB], DefBB, GEPI,
Ptr, PtrOffset);
}
if (GEPI->getType() != RepPtr->getType()) {
BasicBlock::iterator IP = NewVal;
++IP;
// NewVal must be a GEP which must be pointer type, so BitCast
NewVal = new BitCastInst(NewVal, RepPtr->getType(), "", IP);
}
User->replaceUsesOfWith(RepPtr, NewVal);
}
}
/// OptimizeGEPExpression - Since we are doing basic-block-at-a-time instruction
/// selection, we want to be a bit careful about some things. In particular, if
/// we have a GEP instruction that is used in a different block than it is
/// defined, the addressing expression of the GEP cannot be folded into loads or
/// stores that use it. In this case, decompose the GEP and move constant
/// indices into blocks that use it.
static bool OptimizeGEPExpression(GetElementPtrInst *GEPI,
const TargetData *TD) {
// If this GEP is only used inside the block it is defined in, there is no
// need to rewrite it.
bool isUsedOutsideDefBB = false;
BasicBlock *DefBB = GEPI->getParent();
for (Value::use_iterator UI = GEPI->use_begin(), E = GEPI->use_end();
UI != E; ++UI) {
if (cast<Instruction>(*UI)->getParent() != DefBB) {
isUsedOutsideDefBB = true;
break;
}
}
if (!isUsedOutsideDefBB) return false;
// If this GEP has no non-zero constant indices, there is nothing we can do,
// ignore it.
bool hasConstantIndex = false;
bool hasVariableIndex = false;
for (GetElementPtrInst::op_iterator OI = GEPI->op_begin()+1,
E = GEPI->op_end(); OI != E; ++OI) {
if (ConstantInt *CI = dyn_cast<ConstantInt>(*OI)) {
if (CI->getZExtValue()) {
hasConstantIndex = true;
break;
}
} else {
hasVariableIndex = true;
}
}
// If this is a "GEP X, 0, 0, 0", turn this into a cast.
if (!hasConstantIndex && !hasVariableIndex) {
/// The GEP operand must be a pointer, so must its result -> BitCast
Value *NC = new BitCastInst(GEPI->getOperand(0), GEPI->getType(),
GEPI->getName(), GEPI);
GEPI->replaceAllUsesWith(NC);
GEPI->eraseFromParent();
return true;
}
// If this is a GEP &Alloca, 0, 0, forward subst the frame index into uses.
if (!hasConstantIndex && !isa<AllocaInst>(GEPI->getOperand(0)))
return false;
// Otherwise, decompose the GEP instruction into multiplies and adds. Sum the
// constant offset (which we now know is non-zero) and deal with it later.
uint64_t ConstantOffset = 0;
const Type *UIntPtrTy = TD->getIntPtrType();
Value *Ptr = new PtrToIntInst(GEPI->getOperand(0), UIntPtrTy, "", GEPI);
const Type *Ty = GEPI->getOperand(0)->getType();
for (GetElementPtrInst::op_iterator OI = GEPI->op_begin()+1,
E = GEPI->op_end(); OI != E; ++OI) {
Value *Idx = *OI;
if (const StructType *StTy = dyn_cast<StructType>(Ty)) {
unsigned Field = cast<ConstantInt>(Idx)->getZExtValue();
if (Field)
ConstantOffset += TD->getStructLayout(StTy)->getElementOffset(Field);
Ty = StTy->getElementType(Field);
} else {
Ty = cast<SequentialType>(Ty)->getElementType();
// Handle constant subscripts.
if (ConstantInt *CI = dyn_cast<ConstantInt>(Idx)) {
if (CI->getZExtValue() == 0) continue;
ConstantOffset += (int64_t)TD->getTypeSize(Ty)*CI->getSExtValue();
continue;
}
// Ptr = Ptr + Idx * ElementSize;
// Cast Idx to UIntPtrTy if needed.
Idx = CastInst::createIntegerCast(Idx, UIntPtrTy, true/*SExt*/, "", GEPI);
uint64_t ElementSize = TD->getTypeSize(Ty);
// Mask off bits that should not be set.
ElementSize &= ~0ULL >> (64-UIntPtrTy->getPrimitiveSizeInBits());
Constant *SizeCst = ConstantInt::get(UIntPtrTy, ElementSize);
// Multiply by the element size and add to the base.
Idx = BinaryOperator::createMul(Idx, SizeCst, "", GEPI);
Ptr = BinaryOperator::createAdd(Ptr, Idx, "", GEPI);
}
}
// Make sure that the offset fits in uintptr_t.
ConstantOffset &= ~0ULL >> (64-UIntPtrTy->getPrimitiveSizeInBits());
Constant *PtrOffset = ConstantInt::get(UIntPtrTy, ConstantOffset);
// Okay, we have now emitted all of the variable index parts to the BB that
// the GEP is defined in. Loop over all of the using instructions, inserting
// an "add Ptr, ConstantOffset" into each block that uses it and update the
// instruction to use the newly computed value, making GEPI dead. When the
// user is a load or store instruction address, we emit the add into the user
// block, otherwise we use a canonical version right next to the gep (these
// won't be foldable as addresses, so we might as well share the computation).
std::map<BasicBlock*,Instruction*> InsertedExprs;
ReplaceUsesOfGEPInst(GEPI, Ptr, PtrOffset, DefBB, GEPI, InsertedExprs);
// Finally, the GEP is dead, remove it.
GEPI->eraseFromParent();
return true;
}
/// SplitEdgeNicely - Split the critical edge from TI to it's specified
/// successor if it will improve codegen. We only do this if the successor has
/// phi nodes (otherwise critical edges are ok). If there is already another
/// predecessor of the succ that is empty (and thus has no phi nodes), use it
/// instead of introducing a new block.
static void SplitEdgeNicely(TerminatorInst *TI, unsigned SuccNum, Pass *P) {
BasicBlock *TIBB = TI->getParent();
BasicBlock *Dest = TI->getSuccessor(SuccNum);
assert(isa<PHINode>(Dest->begin()) &&
"This should only be called if Dest has a PHI!");
/// TIPHIValues - This array is lazily computed to determine the values of
/// PHIs in Dest that TI would provide.
std::vector<Value*> TIPHIValues;
// Check to see if Dest has any blocks that can be used as a split edge for
// this terminator.
for (pred_iterator PI = pred_begin(Dest), E = pred_end(Dest); PI != E; ++PI) {
BasicBlock *Pred = *PI;
// To be usable, the pred has to end with an uncond branch to the dest.
BranchInst *PredBr = dyn_cast<BranchInst>(Pred->getTerminator());
if (!PredBr || !PredBr->isUnconditional() ||
// Must be empty other than the branch.
&Pred->front() != PredBr)
continue;
// Finally, since we know that Dest has phi nodes in it, we have to make
// sure that jumping to Pred will have the same affect as going to Dest in
// terms of PHI values.
PHINode *PN;
unsigned PHINo = 0;
bool FoundMatch = true;
for (BasicBlock::iterator I = Dest->begin();
(PN = dyn_cast<PHINode>(I)); ++I, ++PHINo) {
if (PHINo == TIPHIValues.size())
TIPHIValues.push_back(PN->getIncomingValueForBlock(TIBB));
// If the PHI entry doesn't work, we can't use this pred.
if (TIPHIValues[PHINo] != PN->getIncomingValueForBlock(Pred)) {
FoundMatch = false;
break;
}
}
// If we found a workable predecessor, change TI to branch to Succ.
if (FoundMatch) {
Dest->removePredecessor(TIBB);
TI->setSuccessor(SuccNum, Pred);
return;
}
}
SplitCriticalEdge(TI, SuccNum, P, true);
}
bool SelectionDAGISel::runOnFunction(Function &Fn) {
MachineFunction &MF = MachineFunction::construct(&Fn, TLI.getTargetMachine());
RegMap = MF.getSSARegMap();
DOUT << "\n\n\n=== " << Fn.getName() << "\n";
// First, split all critical edges.
//
// In this pass we also look for GEP and cast instructions that are used
// across basic blocks and rewrite them to improve basic-block-at-a-time
// selection.
//
bool MadeChange = true;
while (MadeChange) {
MadeChange = false;
for (Function::iterator FNI = Fn.begin(), E = Fn.end(); FNI != E; ++FNI) {
// Split all critical edges where the dest block has a PHI.
TerminatorInst *BBTI = FNI->getTerminator();
if (BBTI->getNumSuccessors() > 1) {
for (unsigned i = 0, e = BBTI->getNumSuccessors(); i != e; ++i)
if (isa<PHINode>(BBTI->getSuccessor(i)->begin()) &&
isCriticalEdge(BBTI, i, true))
SplitEdgeNicely(BBTI, i, this);
}
for (BasicBlock::iterator BBI = FNI->begin(), E = FNI->end(); BBI != E; ) {
Instruction *I = BBI++;
if (CallInst *CI = dyn_cast<CallInst>(I)) {
// If we found an inline asm expession, and if the target knows how to
// lower it to normal LLVM code, do so now.
if (isa<InlineAsm>(CI->getCalledValue()))
if (const TargetAsmInfo *TAI =
TLI.getTargetMachine().getTargetAsmInfo()) {
if (TAI->ExpandInlineAsm(CI))
BBI = FNI->begin();
}
} else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) {
MadeChange |= OptimizeGEPExpression(GEPI, TLI.getTargetData());
} else if (CastInst *CI = dyn_cast<CastInst>(I)) {
// If the source of the cast is a constant, then this should have
// already been constant folded. The only reason NOT to constant fold
// it is if something (e.g. LSR) was careful to place the constant
// evaluation in a block other than then one that uses it (e.g. to hoist
// the address of globals out of a loop). If this is the case, we don't
// want to forward-subst the cast.
if (isa<Constant>(CI->getOperand(0)))
continue;
// If this is a noop copy, sink it into user blocks to reduce the number
// of virtual registers that must be created and coallesced.
MVT::ValueType SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
MVT::ValueType DstVT = TLI.getValueType(CI->getType());
// This is an fp<->int conversion?
if (MVT::isInteger(SrcVT) != MVT::isInteger(DstVT))
continue;
// If this is an extension, it will be a zero or sign extension, which
// isn't a noop.
if (SrcVT < DstVT) continue;
// If these values will be promoted, find out what they will be promoted
// to. This helps us consider truncates on PPC as noop copies when they
// are.
if (TLI.getTypeAction(SrcVT) == TargetLowering::Promote)
SrcVT = TLI.getTypeToTransformTo(SrcVT);
if (TLI.getTypeAction(DstVT) == TargetLowering::Promote)
DstVT = TLI.getTypeToTransformTo(DstVT);
// If, after promotion, these are the same types, this is a noop copy.
if (SrcVT == DstVT)
MadeChange |= OptimizeNoopCopyExpression(CI);
}
}
}
}
FunctionLoweringInfo FuncInfo(TLI, Fn, MF);
for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
SelectBasicBlock(I, MF, FuncInfo);
// Add function live-ins to entry block live-in set.
BasicBlock *EntryBB = &Fn.getEntryBlock();
BB = FuncInfo.MBBMap[EntryBB];
if (!MF.livein_empty())
for (MachineFunction::livein_iterator I = MF.livein_begin(),
E = MF.livein_end(); I != E; ++I)
BB->addLiveIn(I->first);
return true;
}
SDOperand SelectionDAGLowering::CopyValueToVirtualRegister(Value *V,
unsigned Reg) {
SDOperand Op = getValue(V);
assert((Op.getOpcode() != ISD::CopyFromReg ||
cast<RegisterSDNode>(Op.getOperand(1))->getReg() != Reg) &&
"Copy from a reg to the same reg!");
// If this type is not legal, we must make sure to not create an invalid
// register use.
MVT::ValueType SrcVT = Op.getValueType();
MVT::ValueType DestVT = TLI.getTypeToTransformTo(SrcVT);
if (SrcVT == DestVT) {
return DAG.getCopyToReg(getRoot(), Reg, Op);
} else if (SrcVT == MVT::Vector) {
// Handle copies from generic vectors to registers.
MVT::ValueType PTyElementVT, PTyLegalElementVT;
unsigned NE = TLI.getVectorTypeBreakdown(cast<VectorType>(V->getType()),
PTyElementVT, PTyLegalElementVT);
// Insert a VBIT_CONVERT of the input vector to a "N x PTyElementVT"
// MVT::Vector type.
Op = DAG.getNode(ISD::VBIT_CONVERT, MVT::Vector, Op,
DAG.getConstant(NE, MVT::i32),
DAG.getValueType(PTyElementVT));
// Loop over all of the elements of the resultant vector,
// VEXTRACT_VECTOR_ELT'ing them, converting them to PTyLegalElementVT, then
// copying them into output registers.
SmallVector<SDOperand, 8> OutChains;
SDOperand Root = getRoot();
for (unsigned i = 0; i != NE; ++i) {
SDOperand Elt = DAG.getNode(ISD::VEXTRACT_VECTOR_ELT, PTyElementVT,
Op, DAG.getConstant(i, TLI.getPointerTy()));
if (PTyElementVT == PTyLegalElementVT) {
// Elements are legal.
OutChains.push_back(DAG.getCopyToReg(Root, Reg++, Elt));
} else if (PTyLegalElementVT > PTyElementVT) {
// Elements are promoted.
if (MVT::isFloatingPoint(PTyLegalElementVT))
Elt = DAG.getNode(ISD::FP_EXTEND, PTyLegalElementVT, Elt);
else
Elt = DAG.getNode(ISD::ANY_EXTEND, PTyLegalElementVT, Elt);
OutChains.push_back(DAG.getCopyToReg(Root, Reg++, Elt));
} else {
// Elements are expanded.
// The src value is expanded into multiple registers.
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, PTyLegalElementVT,
Elt, DAG.getConstant(0, TLI.getPointerTy()));
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, PTyLegalElementVT,
Elt, DAG.getConstant(1, TLI.getPointerTy()));
OutChains.push_back(DAG.getCopyToReg(Root, Reg++, Lo));
OutChains.push_back(DAG.getCopyToReg(Root, Reg++, Hi));
}
}
return DAG.getNode(ISD::TokenFactor, MVT::Other,
&OutChains[0], OutChains.size());
} else if (TLI.getTypeAction(SrcVT) == TargetLowering::Promote) {
// The src value is promoted to the register.
if (MVT::isFloatingPoint(SrcVT))
Op = DAG.getNode(ISD::FP_EXTEND, DestVT, Op);
else
Op = DAG.getNode(ISD::ANY_EXTEND, DestVT, Op);
return DAG.getCopyToReg(getRoot(), Reg, Op);
} else {
DestVT = TLI.getTypeToExpandTo(SrcVT);
unsigned NumVals = TLI.getNumElements(SrcVT);
if (NumVals == 1)
return DAG.getCopyToReg(getRoot(), Reg,
DAG.getNode(ISD::BIT_CONVERT, DestVT, Op));
assert(NumVals == 2 && "1 to 4 (and more) expansion not implemented!");
// The src value is expanded into multiple registers.
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, DestVT,
Op, DAG.getConstant(0, TLI.getPointerTy()));
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, DestVT,
Op, DAG.getConstant(1, TLI.getPointerTy()));
Op = DAG.getCopyToReg(getRoot(), Reg, Lo);
return DAG.getCopyToReg(Op, Reg+1, Hi);
}
}
void SelectionDAGISel::
LowerArguments(BasicBlock *LLVMBB, SelectionDAGLowering &SDL,
std::vector<SDOperand> &UnorderedChains) {
// If this is the entry block, emit arguments.
Function &F = *LLVMBB->getParent();
FunctionLoweringInfo &FuncInfo = SDL.FuncInfo;
SDOperand OldRoot = SDL.DAG.getRoot();
std::vector<SDOperand> Args = TLI.LowerArguments(F, SDL.DAG);
unsigned a = 0;
for (Function::arg_iterator AI = F.arg_begin(), E = F.arg_end();
AI != E; ++AI, ++a)
if (!AI->use_empty()) {
SDL.setValue(AI, Args[a]);
// If this argument is live outside of the entry block, insert a copy from
// whereever we got it to the vreg that other BB's will reference it as.
if (FuncInfo.ValueMap.count(AI)) {
SDOperand Copy =
SDL.CopyValueToVirtualRegister(AI, FuncInfo.ValueMap[AI]);
UnorderedChains.push_back(Copy);
}
}
// Finally, if the target has anything special to do, allow it to do so.
// FIXME: this should insert code into the DAG!
EmitFunctionEntryCode(F, SDL.DAG.getMachineFunction());
}
void SelectionDAGISel::BuildSelectionDAG(SelectionDAG &DAG, BasicBlock *LLVMBB,
std::vector<std::pair<MachineInstr*, unsigned> > &PHINodesToUpdate,
FunctionLoweringInfo &FuncInfo) {
SelectionDAGLowering SDL(DAG, TLI, FuncInfo);
std::vector<SDOperand> UnorderedChains;
// Lower any arguments needed in this block if this is the entry block.
if (LLVMBB == &LLVMBB->getParent()->front())
LowerArguments(LLVMBB, SDL, UnorderedChains);
BB = FuncInfo.MBBMap[LLVMBB];
SDL.setCurrentBasicBlock(BB);
// Lower all of the non-terminator instructions.
for (BasicBlock::iterator I = LLVMBB->begin(), E = --LLVMBB->end();
I != E; ++I)
SDL.visit(*I);
// Ensure that all instructions which are used outside of their defining
// blocks are available as virtual registers.
for (BasicBlock::iterator I = LLVMBB->begin(), E = LLVMBB->end(); I != E;++I)
if (!I->use_empty() && !isa<PHINode>(I)) {
DenseMap<const Value*, unsigned>::iterator VMI =FuncInfo.ValueMap.find(I);
if (VMI != FuncInfo.ValueMap.end())
UnorderedChains.push_back(
SDL.CopyValueToVirtualRegister(I, VMI->second));
}
// Handle PHI nodes in successor blocks. Emit code into the SelectionDAG to
// ensure constants are generated when needed. Remember the virtual registers
// that need to be added to the Machine PHI nodes as input. We cannot just
// directly add them, because expansion might result in multiple MBB's for one
// BB. As such, the start of the BB might correspond to a different MBB than
// the end.
//
TerminatorInst *TI = LLVMBB->getTerminator();
// Emit constants only once even if used by multiple PHI nodes.
std::map<Constant*, unsigned> ConstantsOut;
// Vector bool would be better, but vector<bool> is really slow.
std::vector<unsigned char> SuccsHandled;
if (TI->getNumSuccessors())
SuccsHandled.resize(BB->getParent()->getNumBlockIDs());
// Check successor nodes PHI nodes that expect a constant to be available from
// this block.
for (unsigned succ = 0, e = TI->getNumSuccessors(); succ != e; ++succ) {
BasicBlock *SuccBB = TI->getSuccessor(succ);
if (!isa<PHINode>(SuccBB->begin())) continue;
MachineBasicBlock *SuccMBB = FuncInfo.MBBMap[SuccBB];
// If this terminator has multiple identical successors (common for
// switches), only handle each succ once.
unsigned SuccMBBNo = SuccMBB->getNumber();
if (SuccsHandled[SuccMBBNo]) continue;
SuccsHandled[SuccMBBNo] = true;
MachineBasicBlock::iterator MBBI = SuccMBB->begin();
PHINode *PN;
// At this point we know that there is a 1-1 correspondence between LLVM PHI
// nodes and Machine PHI nodes, but the incoming operands have not been
// emitted yet.
for (BasicBlock::iterator I = SuccBB->begin();
(PN = dyn_cast<PHINode>(I)); ++I) {
// Ignore dead phi's.
if (PN->use_empty()) continue;
unsigned Reg;
Value *PHIOp = PN->getIncomingValueForBlock(LLVMBB);
if (Constant *C = dyn_cast<Constant>(PHIOp)) {
unsigned &RegOut = ConstantsOut[C];
if (RegOut == 0) {
RegOut = FuncInfo.CreateRegForValue(C);
UnorderedChains.push_back(
SDL.CopyValueToVirtualRegister(C, RegOut));
}
Reg = RegOut;
} else {
Reg = FuncInfo.ValueMap[PHIOp];
if (Reg == 0) {
assert(isa<AllocaInst>(PHIOp) &&
FuncInfo.StaticAllocaMap.count(cast<AllocaInst>(PHIOp)) &&
"Didn't codegen value into a register!??");
Reg = FuncInfo.CreateRegForValue(PHIOp);
UnorderedChains.push_back(
SDL.CopyValueToVirtualRegister(PHIOp, Reg));
}
}
// Remember that this register needs to added to the machine PHI node as
// the input for this MBB.
MVT::ValueType VT = TLI.getValueType(PN->getType());
unsigned NumElements;
if (VT != MVT::Vector)
NumElements = TLI.getNumElements(VT);
else {
MVT::ValueType VT1,VT2;
NumElements =
TLI.getVectorTypeBreakdown(cast<VectorType>(PN->getType()),
VT1, VT2);
}
for (unsigned i = 0, e = NumElements; i != e; ++i)
PHINodesToUpdate.push_back(std::make_pair(MBBI++, Reg+i));
}
}
ConstantsOut.clear();
// Turn all of the unordered chains into one factored node.
if (!UnorderedChains.empty()) {
SDOperand Root = SDL.getRoot();
if (Root.getOpcode() != ISD::EntryToken) {
unsigned i = 0, e = UnorderedChains.size();
for (; i != e; ++i) {
assert(UnorderedChains[i].Val->getNumOperands() > 1);
if (UnorderedChains[i].Val->getOperand(0) == Root)
break; // Don't add the root if we already indirectly depend on it.
}
if (i == e)
UnorderedChains.push_back(Root);
}
DAG.setRoot(DAG.getNode(ISD::TokenFactor, MVT::Other,
&UnorderedChains[0], UnorderedChains.size()));
}
// Lower the terminator after the copies are emitted.
SDL.visit(*LLVMBB->getTerminator());
// Copy over any CaseBlock records that may now exist due to SwitchInst
// lowering, as well as any jump table information.
SwitchCases.clear();
SwitchCases = SDL.SwitchCases;
JT = SDL.JT;
// Make sure the root of the DAG is up-to-date.
DAG.setRoot(SDL.getRoot());
}
void SelectionDAGISel::CodeGenAndEmitDAG(SelectionDAG &DAG) {
// Get alias analysis for load/store combining.
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
// Run the DAG combiner in pre-legalize mode.
DAG.Combine(false, AA);
DOUT << "Lowered selection DAG:\n";
DEBUG(DAG.dump());
// Second step, hack on the DAG until it only uses operations and types that
// the target supports.
DAG.Legalize();
DOUT << "Legalized selection DAG:\n";
DEBUG(DAG.dump());
// Run the DAG combiner in post-legalize mode.
DAG.Combine(true, AA);
if (ViewISelDAGs) DAG.viewGraph();
// Third, instruction select all of the operations to machine code, adding the
// code to the MachineBasicBlock.
InstructionSelectBasicBlock(DAG);
DOUT << "Selected machine code:\n";
DEBUG(BB->dump());
}
void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB, MachineFunction &MF,
FunctionLoweringInfo &FuncInfo) {
std::vector<std::pair<MachineInstr*, unsigned> > PHINodesToUpdate;
{
SelectionDAG DAG(TLI, MF, getAnalysisToUpdate<MachineModuleInfo>());
CurDAG = &DAG;
// First step, lower LLVM code to some DAG. This DAG may use operations and
// types that are not supported by the target.
BuildSelectionDAG(DAG, LLVMBB, PHINodesToUpdate, FuncInfo);
// Second step, emit the lowered DAG as machine code.
CodeGenAndEmitDAG(DAG);
}
// Next, now that we know what the last MBB the LLVM BB expanded is, update
// PHI nodes in successors.
if (SwitchCases.empty() && JT.Reg == 0) {
for (unsigned i = 0, e = PHINodesToUpdate.size(); i != e; ++i) {
MachineInstr *PHI = PHINodesToUpdate[i].first;
assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
"This is not a machine PHI node that we are updating!");
PHI->addRegOperand(PHINodesToUpdate[i].second, false);
PHI->addMachineBasicBlockOperand(BB);
}
return;
}
// If the JumpTable record is filled in, then we need to emit a jump table.
// Updating the PHI nodes is tricky in this case, since we need to determine
// whether the PHI is a successor of the range check MBB or the jump table MBB
if (JT.Reg) {
assert(SwitchCases.empty() && "Cannot have jump table and lowered switch");
SelectionDAG SDAG(TLI, MF, getAnalysisToUpdate<MachineModuleInfo>());
CurDAG = &SDAG;
SelectionDAGLowering SDL(SDAG, TLI, FuncInfo);
MachineBasicBlock *RangeBB = BB;
// Set the current basic block to the mbb we wish to insert the code into
BB = JT.MBB;
SDL.setCurrentBasicBlock(BB);
// Emit the code
SDL.visitJumpTable(JT);
SDAG.setRoot(SDL.getRoot());
CodeGenAndEmitDAG(SDAG);
// Update PHI Nodes
for (unsigned pi = 0, pe = PHINodesToUpdate.size(); pi != pe; ++pi) {
MachineInstr *PHI = PHINodesToUpdate[pi].first;
MachineBasicBlock *PHIBB = PHI->getParent();
assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
"This is not a machine PHI node that we are updating!");
if (PHIBB == JT.Default) {
PHI->addRegOperand(PHINodesToUpdate[pi].second, false);
PHI->addMachineBasicBlockOperand(RangeBB);
}
if (BB->succ_end() != std::find(BB->succ_begin(),BB->succ_end(), PHIBB)) {
PHI->addRegOperand(PHINodesToUpdate[pi].second, false);
PHI->addMachineBasicBlockOperand(BB);
}
}
return;
}
// If the switch block involved a branch to one of the actual successors, we
// need to update PHI nodes in that block.
for (unsigned i = 0, e = PHINodesToUpdate.size(); i != e; ++i) {
MachineInstr *PHI = PHINodesToUpdate[i].first;
assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
"This is not a machine PHI node that we are updating!");
if (BB->isSuccessor(PHI->getParent())) {
PHI->addRegOperand(PHINodesToUpdate[i].second, false);
PHI->addMachineBasicBlockOperand(BB);
}
}
// If we generated any switch lowering information, build and codegen any
// additional DAGs necessary.
for (unsigned i = 0, e = SwitchCases.size(); i != e; ++i) {
SelectionDAG SDAG(TLI, MF, getAnalysisToUpdate<MachineModuleInfo>());
CurDAG = &SDAG;
SelectionDAGLowering SDL(SDAG, TLI, FuncInfo);
// Set the current basic block to the mbb we wish to insert the code into
BB = SwitchCases[i].ThisBB;
SDL.setCurrentBasicBlock(BB);
// Emit the code
SDL.visitSwitchCase(SwitchCases[i]);
SDAG.setRoot(SDL.getRoot());
CodeGenAndEmitDAG(SDAG);
// Handle any PHI nodes in successors of this chunk, as if we were coming
// from the original BB before switch expansion. Note that PHI nodes can
// occur multiple times in PHINodesToUpdate. We have to be very careful to
// handle them the right number of times.
while ((BB = SwitchCases[i].TrueBB)) { // Handle LHS and RHS.
for (MachineBasicBlock::iterator Phi = BB->begin();
Phi != BB->end() && Phi->getOpcode() == TargetInstrInfo::PHI; ++Phi){
// This value for this PHI node is recorded in PHINodesToUpdate, get it.
for (unsigned pn = 0; ; ++pn) {
assert(pn != PHINodesToUpdate.size() && "Didn't find PHI entry!");
if (PHINodesToUpdate[pn].first == Phi) {
Phi->addRegOperand(PHINodesToUpdate[pn].second, false);
Phi->addMachineBasicBlockOperand(SwitchCases[i].ThisBB);
break;
}
}
}
// Don't process RHS if same block as LHS.
if (BB == SwitchCases[i].FalseBB)
SwitchCases[i].FalseBB = 0;
// If we haven't handled the RHS, do so now. Otherwise, we're done.
SwitchCases[i].TrueBB = SwitchCases[i].FalseBB;
SwitchCases[i].FalseBB = 0;
}
assert(SwitchCases[i].TrueBB == 0 && SwitchCases[i].FalseBB == 0);
}
}
//===----------------------------------------------------------------------===//
/// ScheduleAndEmitDAG - Pick a safe ordering and emit instructions for each
/// target node in the graph.
void SelectionDAGISel::ScheduleAndEmitDAG(SelectionDAG &DAG) {
if (ViewSchedDAGs) DAG.viewGraph();
RegisterScheduler::FunctionPassCtor Ctor = RegisterScheduler::getDefault();
if (!Ctor) {
Ctor = ISHeuristic;
RegisterScheduler::setDefault(Ctor);
}
ScheduleDAG *SL = Ctor(this, &DAG, BB);
BB = SL->Run();
delete SL;
}
HazardRecognizer *SelectionDAGISel::CreateTargetHazardRecognizer() {
return new HazardRecognizer();
}
//===----------------------------------------------------------------------===//
// Helper functions used by the generated instruction selector.
//===----------------------------------------------------------------------===//
// Calls to these methods are generated by tblgen.
/// CheckAndMask - The isel is trying to match something like (and X, 255). If
/// the dag combiner simplified the 255, we still want to match. RHS is the
/// actual value in the DAG on the RHS of an AND, and DesiredMaskS is the value
/// specified in the .td file (e.g. 255).
bool SelectionDAGISel::CheckAndMask(SDOperand LHS, ConstantSDNode *RHS,
int64_t DesiredMaskS) {
uint64_t ActualMask = RHS->getValue();
uint64_t DesiredMask =DesiredMaskS & MVT::getIntVTBitMask(LHS.getValueType());
// If the actual mask exactly matches, success!
if (ActualMask == DesiredMask)
return true;
// If the actual AND mask is allowing unallowed bits, this doesn't match.
if (ActualMask & ~DesiredMask)
return false;
// Otherwise, the DAG Combiner may have proven that the value coming in is
// either already zero or is not demanded. Check for known zero input bits.
uint64_t NeededMask = DesiredMask & ~ActualMask;
if (getTargetLowering().MaskedValueIsZero(LHS, NeededMask))
return true;
// TODO: check to see if missing bits are just not demanded.
// Otherwise, this pattern doesn't match.
return false;
}
/// CheckOrMask - The isel is trying to match something like (or X, 255). If
/// the dag combiner simplified the 255, we still want to match. RHS is the
/// actual value in the DAG on the RHS of an OR, and DesiredMaskS is the value
/// specified in the .td file (e.g. 255).
bool SelectionDAGISel::CheckOrMask(SDOperand LHS, ConstantSDNode *RHS,
int64_t DesiredMaskS) {
uint64_t ActualMask = RHS->getValue();
uint64_t DesiredMask =DesiredMaskS & MVT::getIntVTBitMask(LHS.getValueType());
// If the actual mask exactly matches, success!
if (ActualMask == DesiredMask)
return true;
// If the actual AND mask is allowing unallowed bits, this doesn't match.
if (ActualMask & ~DesiredMask)
return false;
// Otherwise, the DAG Combiner may have proven that the value coming in is
// either already zero or is not demanded. Check for known zero input bits.
uint64_t NeededMask = DesiredMask & ~ActualMask;
uint64_t KnownZero, KnownOne;
getTargetLowering().ComputeMaskedBits(LHS, NeededMask, KnownZero, KnownOne);
// If all the missing bits in the or are already known to be set, match!
if ((NeededMask & KnownOne) == NeededMask)
return true;
// TODO: check to see if missing bits are just not demanded.
// Otherwise, this pattern doesn't match.
return false;
}
/// SelectInlineAsmMemoryOperands - Calls to this are automatically generated
/// by tblgen. Others should not call it.
void SelectionDAGISel::
SelectInlineAsmMemoryOperands(std::vector<SDOperand> &Ops, SelectionDAG &DAG) {
std::vector<SDOperand> InOps;
std::swap(InOps, Ops);
Ops.push_back(InOps[0]); // input chain.
Ops.push_back(InOps[1]); // input asm string.
unsigned i = 2, e = InOps.size();
if (InOps[e-1].getValueType() == MVT::Flag)
--e; // Don't process a flag operand if it is here.
while (i != e) {
unsigned Flags = cast<ConstantSDNode>(InOps[i])->getValue();
if ((Flags & 7) != 4 /*MEM*/) {
// Just skip over this operand, copying the operands verbatim.
Ops.insert(Ops.end(), InOps.begin()+i, InOps.begin()+i+(Flags >> 3) + 1);
i += (Flags >> 3) + 1;
} else {
assert((Flags >> 3) == 1 && "Memory operand with multiple values?");
// Otherwise, this is a memory operand. Ask the target to select it.
std::vector<SDOperand> SelOps;
if (SelectInlineAsmMemoryOperand(InOps[i+1], 'm', SelOps, DAG)) {
cerr << "Could not match memory address. Inline asm failure!\n";
exit(1);
}
// Add this to the output node.
Ops.push_back(DAG.getTargetConstant(4/*MEM*/ | (SelOps.size() << 3),
MVT::i32));
Ops.insert(Ops.end(), SelOps.begin(), SelOps.end());
i += 2;
}
}
// Add the flag input back if present.
if (e != InOps.size())
Ops.push_back(InOps.back());
}
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