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llvm-6502/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
Nate Begeman e179584f9b Change how FP immediates are handled. 
1) ConstantFP is now expand by default
2) ConstantFP is not turned into TargetConstantFP during Legalize
   if it is legal.

This allows ConstantFP to be handled like Constant, allowing for 
targets that can encode FP immediates as MachineOperands.

As a bonus, fix up Itanium FP constants, which now correctly match,
and match more constants!  Hooray.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47121 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-14 08:57:00 +00:00

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//===---- ScheduleDAG.cpp - Implement the ScheduleDAG class ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements a simple two pass scheduler. The first pass attempts to push
// backward any lengthy instructions and critical paths. The second pass packs
// instructions into semi-optimal time slots.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "pre-RA-sched"
#include "llvm/Constants.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
ScheduleDAG::ScheduleDAG(SelectionDAG &dag, MachineBasicBlock *bb,
const TargetMachine &tm)
: DAG(dag), BB(bb), TM(tm), RegInfo(BB->getParent()->getRegInfo()) {
TII = TM.getInstrInfo();
MF = &DAG.getMachineFunction();
TRI = TM.getRegisterInfo();
ConstPool = BB->getParent()->getConstantPool();
}
/// CheckForPhysRegDependency - Check if the dependency between def and use of
/// a specified operand is a physical register dependency. If so, returns the
/// register and the cost of copying the register.
static void CheckForPhysRegDependency(SDNode *Def, SDNode *Use, unsigned Op,
const TargetRegisterInfo *TRI,
const TargetInstrInfo *TII,
unsigned &PhysReg, int &Cost) {
if (Op != 2 || Use->getOpcode() != ISD::CopyToReg)
return;
unsigned Reg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
if (TargetRegisterInfo::isVirtualRegister(Reg))
return;
unsigned ResNo = Use->getOperand(2).ResNo;
if (Def->isTargetOpcode()) {
const TargetInstrDesc &II = TII->get(Def->getTargetOpcode());
if (ResNo >= II.getNumDefs() &&
II.ImplicitDefs[ResNo - II.getNumDefs()] == Reg) {
PhysReg = Reg;
const TargetRegisterClass *RC =
TRI->getPhysicalRegisterRegClass(Def->getValueType(ResNo), Reg);
Cost = RC->getCopyCost();
}
}
}
SUnit *ScheduleDAG::Clone(SUnit *Old) {
SUnit *SU = NewSUnit(Old->Node);
for (unsigned i = 0, e = SU->FlaggedNodes.size(); i != e; ++i)
SU->FlaggedNodes.push_back(SU->FlaggedNodes[i]);
SU->InstanceNo = SUnitMap[Old->Node].size();
SU->Latency = Old->Latency;
SU->isTwoAddress = Old->isTwoAddress;
SU->isCommutable = Old->isCommutable;
SU->hasPhysRegDefs = Old->hasPhysRegDefs;
SUnitMap[Old->Node].push_back(SU);
return SU;
}
/// BuildSchedUnits - Build SUnits from the selection dag that we are input.
/// This SUnit graph is similar to the SelectionDAG, but represents flagged
/// together nodes with a single SUnit.
void ScheduleDAG::BuildSchedUnits() {
// Reserve entries in the vector for each of the SUnits we are creating. This
// ensure that reallocation of the vector won't happen, so SUnit*'s won't get
// invalidated.
SUnits.reserve(std::distance(DAG.allnodes_begin(), DAG.allnodes_end()));
for (SelectionDAG::allnodes_iterator NI = DAG.allnodes_begin(),
E = DAG.allnodes_end(); NI != E; ++NI) {
if (isPassiveNode(NI)) // Leaf node, e.g. a TargetImmediate.
continue;
// If this node has already been processed, stop now.
if (SUnitMap[NI].size()) continue;
SUnit *NodeSUnit = NewSUnit(NI);
// See if anything is flagged to this node, if so, add them to flagged
// nodes. Nodes can have at most one flag input and one flag output. Flags
// are required the be the last operand and result of a node.
// Scan up, adding flagged preds to FlaggedNodes.
SDNode *N = NI;
if (N->getNumOperands() &&
N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Flag) {
do {
N = N->getOperand(N->getNumOperands()-1).Val;
NodeSUnit->FlaggedNodes.push_back(N);
SUnitMap[N].push_back(NodeSUnit);
} while (N->getNumOperands() &&
N->getOperand(N->getNumOperands()-1).getValueType()== MVT::Flag);
std::reverse(NodeSUnit->FlaggedNodes.begin(),
NodeSUnit->FlaggedNodes.end());
}
// Scan down, adding this node and any flagged succs to FlaggedNodes if they
// have a user of the flag operand.
N = NI;
while (N->getValueType(N->getNumValues()-1) == MVT::Flag) {
SDOperand FlagVal(N, N->getNumValues()-1);
// There are either zero or one users of the Flag result.
bool HasFlagUse = false;
for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end();
UI != E; ++UI)
if (FlagVal.isOperand(*UI)) {
HasFlagUse = true;
NodeSUnit->FlaggedNodes.push_back(N);
SUnitMap[N].push_back(NodeSUnit);
N = *UI;
break;
}
if (!HasFlagUse) break;
}
// Now all flagged nodes are in FlaggedNodes and N is the bottom-most node.
// Update the SUnit
NodeSUnit->Node = N;
SUnitMap[N].push_back(NodeSUnit);
ComputeLatency(NodeSUnit);
}
// Pass 2: add the preds, succs, etc.
for (unsigned su = 0, e = SUnits.size(); su != e; ++su) {
SUnit *SU = &SUnits[su];
SDNode *MainNode = SU->Node;
if (MainNode->isTargetOpcode()) {
unsigned Opc = MainNode->getTargetOpcode();
const TargetInstrDesc &TID = TII->get(Opc);
for (unsigned i = 0; i != TID.getNumOperands(); ++i) {
if (TID.getOperandConstraint(i, TOI::TIED_TO) != -1) {
SU->isTwoAddress = true;
break;
}
}
if (TID.isCommutable())
SU->isCommutable = true;
}
// Find all predecessors and successors of the group.
// Temporarily add N to make code simpler.
SU->FlaggedNodes.push_back(MainNode);
for (unsigned n = 0, e = SU->FlaggedNodes.size(); n != e; ++n) {
SDNode *N = SU->FlaggedNodes[n];
if (N->isTargetOpcode() &&
TII->get(N->getTargetOpcode()).getImplicitDefs() &&
CountResults(N) > TII->get(N->getTargetOpcode()).getNumDefs())
SU->hasPhysRegDefs = true;
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
SDNode *OpN = N->getOperand(i).Val;
if (isPassiveNode(OpN)) continue; // Not scheduled.
SUnit *OpSU = SUnitMap[OpN].front();
assert(OpSU && "Node has no SUnit!");
if (OpSU == SU) continue; // In the same group.
MVT::ValueType OpVT = N->getOperand(i).getValueType();
assert(OpVT != MVT::Flag && "Flagged nodes should be in same sunit!");
bool isChain = OpVT == MVT::Other;
unsigned PhysReg = 0;
int Cost = 1;
// Determine if this is a physical register dependency.
CheckForPhysRegDependency(OpN, N, i, TRI, TII, PhysReg, Cost);
SU->addPred(OpSU, isChain, false, PhysReg, Cost);
}
}
// Remove MainNode from FlaggedNodes again.
SU->FlaggedNodes.pop_back();
}
return;
}
void ScheduleDAG::ComputeLatency(SUnit *SU) {
const InstrItineraryData &InstrItins = TM.getInstrItineraryData();
// Compute the latency for the node. We use the sum of the latencies for
// all nodes flagged together into this SUnit.
if (InstrItins.isEmpty()) {
// No latency information.
SU->Latency = 1;
} else {
SU->Latency = 0;
if (SU->Node->isTargetOpcode()) {
unsigned SchedClass =
TII->get(SU->Node->getTargetOpcode()).getSchedClass();
InstrStage *S = InstrItins.begin(SchedClass);
InstrStage *E = InstrItins.end(SchedClass);
for (; S != E; ++S)
SU->Latency += S->Cycles;
}
for (unsigned i = 0, e = SU->FlaggedNodes.size(); i != e; ++i) {
SDNode *FNode = SU->FlaggedNodes[i];
if (FNode->isTargetOpcode()) {
unsigned SchedClass =TII->get(FNode->getTargetOpcode()).getSchedClass();
InstrStage *S = InstrItins.begin(SchedClass);
InstrStage *E = InstrItins.end(SchedClass);
for (; S != E; ++S)
SU->Latency += S->Cycles;
}
}
}
}
void ScheduleDAG::CalculateDepths() {
std::vector<std::pair<SUnit*, unsigned> > WorkList;
for (unsigned i = 0, e = SUnits.size(); i != e; ++i)
if (SUnits[i].Preds.empty())
WorkList.push_back(std::make_pair(&SUnits[i], 0U));
while (!WorkList.empty()) {
SUnit *SU = WorkList.back().first;
unsigned Depth = WorkList.back().second;
WorkList.pop_back();
if (SU->Depth == 0 || Depth > SU->Depth) {
SU->Depth = Depth;
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I)
WorkList.push_back(std::make_pair(I->Dep, Depth+1));
}
}
}
void ScheduleDAG::CalculateHeights() {
std::vector<std::pair<SUnit*, unsigned> > WorkList;
SUnit *Root = SUnitMap[DAG.getRoot().Val].front();
WorkList.push_back(std::make_pair(Root, 0U));
while (!WorkList.empty()) {
SUnit *SU = WorkList.back().first;
unsigned Height = WorkList.back().second;
WorkList.pop_back();
if (SU->Height == 0 || Height > SU->Height) {
SU->Height = Height;
for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I)
WorkList.push_back(std::make_pair(I->Dep, Height+1));
}
}
}
/// CountResults - The results of target nodes have register or immediate
/// operands first, then an optional chain, and optional flag operands (which do
/// not go into the resulting MachineInstr).
unsigned ScheduleDAG::CountResults(SDNode *Node) {
unsigned N = Node->getNumValues();
while (N && Node->getValueType(N - 1) == MVT::Flag)
--N;
if (N && Node->getValueType(N - 1) == MVT::Other)
--N; // Skip over chain result.
return N;
}
/// CountOperands - The inputs to target nodes have any actual inputs first,
/// followed by optional memory operands chain operand, then flag operands.
/// Compute the number of actual operands that will go into the resulting
/// MachineInstr.
unsigned ScheduleDAG::CountOperands(SDNode *Node) {
unsigned N = Node->getNumOperands();
while (N && Node->getOperand(N - 1).getValueType() == MVT::Flag)
--N;
if (N && Node->getOperand(N - 1).getValueType() == MVT::Other)
--N; // Ignore chain if it exists.
while (N && isa<MemOperandSDNode>(Node->getOperand(N - 1).Val))
--N; // Ignore MemOperand nodes
return N;
}
/// CountMemOperands - Find the index of the last MemOperandSDNode operand
unsigned ScheduleDAG::CountMemOperands(SDNode *Node) {
unsigned N = Node->getNumOperands();
while (N && Node->getOperand(N - 1).getValueType() == MVT::Flag)
--N;
if (N && Node->getOperand(N - 1).getValueType() == MVT::Other)
--N; // Ignore chain if it exists.
return N;
}
static const TargetRegisterClass *getInstrOperandRegClass(
const TargetRegisterInfo *TRI,
const TargetInstrInfo *TII,
const TargetInstrDesc &II,
unsigned Op) {
if (Op >= II.getNumOperands()) {
assert(II.isVariadic() && "Invalid operand # of instruction");
return NULL;
}
if (II.OpInfo[Op].isLookupPtrRegClass())
return TII->getPointerRegClass();
return TRI->getRegClass(II.OpInfo[Op].RegClass);
}
void ScheduleDAG::EmitCopyFromReg(SDNode *Node, unsigned ResNo,
unsigned InstanceNo, unsigned SrcReg,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
unsigned VRBase = 0;
if (TargetRegisterInfo::isVirtualRegister(SrcReg)) {
// Just use the input register directly!
if (InstanceNo > 0)
VRBaseMap.erase(SDOperand(Node, ResNo));
bool isNew = VRBaseMap.insert(std::make_pair(SDOperand(Node,ResNo),SrcReg));
assert(isNew && "Node emitted out of order - early");
return;
}
// If the node is only used by a CopyToReg and the dest reg is a vreg, use
// the CopyToReg'd destination register instead of creating a new vreg.
bool MatchReg = true;
for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
UI != E; ++UI) {
SDNode *Use = *UI;
bool Match = true;
if (Use->getOpcode() == ISD::CopyToReg &&
Use->getOperand(2).Val == Node &&
Use->getOperand(2).ResNo == ResNo) {
unsigned DestReg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
VRBase = DestReg;
Match = false;
} else if (DestReg != SrcReg)
Match = false;
} else {
for (unsigned i = 0, e = Use->getNumOperands(); i != e; ++i) {
SDOperand Op = Use->getOperand(i);
if (Op.Val != Node || Op.ResNo != ResNo)
continue;
MVT::ValueType VT = Node->getValueType(Op.ResNo);
if (VT != MVT::Other && VT != MVT::Flag)
Match = false;
}
}
MatchReg &= Match;
if (VRBase)
break;
}
const TargetRegisterClass *TRC = 0;
// Figure out the register class to create for the destreg.
if (VRBase)
TRC = RegInfo.getRegClass(VRBase);
else
TRC = TRI->getPhysicalRegisterRegClass(Node->getValueType(ResNo), SrcReg);
// If all uses are reading from the src physical register and copying the
// register is either impossible or very expensive, then don't create a copy.
if (MatchReg && TRC->getCopyCost() < 0) {
VRBase = SrcReg;
} else {
// Create the reg, emit the copy.
VRBase = RegInfo.createVirtualRegister(TRC);
TII->copyRegToReg(*BB, BB->end(), VRBase, SrcReg, TRC, TRC);
}
if (InstanceNo > 0)
VRBaseMap.erase(SDOperand(Node, ResNo));
bool isNew = VRBaseMap.insert(std::make_pair(SDOperand(Node,ResNo), VRBase));
assert(isNew && "Node emitted out of order - early");
}
void ScheduleDAG::CreateVirtualRegisters(SDNode *Node,
MachineInstr *MI,
const TargetInstrDesc &II,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
for (unsigned i = 0; i < II.getNumDefs(); ++i) {
// If the specific node value is only used by a CopyToReg and the dest reg
// is a vreg, use the CopyToReg'd destination register instead of creating
// a new vreg.
unsigned VRBase = 0;
for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
UI != E; ++UI) {
SDNode *Use = *UI;
if (Use->getOpcode() == ISD::CopyToReg &&
Use->getOperand(2).Val == Node &&
Use->getOperand(2).ResNo == i) {
unsigned Reg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
if (TargetRegisterInfo::isVirtualRegister(Reg)) {
VRBase = Reg;
MI->addOperand(MachineOperand::CreateReg(Reg, true));
break;
}
}
}
// Create the result registers for this node and add the result regs to
// the machine instruction.
if (VRBase == 0) {
const TargetRegisterClass *RC = getInstrOperandRegClass(TRI, TII, II, i);
assert(RC && "Isn't a register operand!");
VRBase = RegInfo.createVirtualRegister(RC);
MI->addOperand(MachineOperand::CreateReg(VRBase, true));
}
bool isNew = VRBaseMap.insert(std::make_pair(SDOperand(Node,i), VRBase));
assert(isNew && "Node emitted out of order - early");
}
}
/// getVR - Return the virtual register corresponding to the specified result
/// of the specified node.
static unsigned getVR(SDOperand Op, DenseMap<SDOperand, unsigned> &VRBaseMap) {
DenseMap<SDOperand, unsigned>::iterator I = VRBaseMap.find(Op);
assert(I != VRBaseMap.end() && "Node emitted out of order - late");
return I->second;
}
/// AddOperand - Add the specified operand to the specified machine instr. II
/// specifies the instruction information for the node, and IIOpNum is the
/// operand number (in the II) that we are adding. IIOpNum and II are used for
/// assertions only.
void ScheduleDAG::AddOperand(MachineInstr *MI, SDOperand Op,
unsigned IIOpNum,
const TargetInstrDesc *II,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
if (Op.isTargetOpcode()) {
// Note that this case is redundant with the final else block, but we
// include it because it is the most common and it makes the logic
// simpler here.
assert(Op.getValueType() != MVT::Other &&
Op.getValueType() != MVT::Flag &&
"Chain and flag operands should occur at end of operand list!");
// Get/emit the operand.
unsigned VReg = getVR(Op, VRBaseMap);
const TargetInstrDesc &TID = MI->getDesc();
bool isOptDef = (IIOpNum < TID.getNumOperands())
? (TID.OpInfo[IIOpNum].isOptionalDef()) : false;
MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef));
// Verify that it is right.
assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
if (II) {
const TargetRegisterClass *RC =
getInstrOperandRegClass(TRI, TII, *II, IIOpNum);
assert(RC && "Don't have operand info for this instruction!");
const TargetRegisterClass *VRC = RegInfo.getRegClass(VReg);
if (VRC != RC) {
cerr << "Register class of operand and regclass of use don't agree!\n";
#ifndef NDEBUG
cerr << "Operand = " << IIOpNum << "\n";
cerr << "Op->Val = "; Op.Val->dump(&DAG); cerr << "\n";
cerr << "MI = "; MI->print(cerr);
cerr << "VReg = " << VReg << "\n";
cerr << "VReg RegClass size = " << VRC->getSize()
<< ", align = " << VRC->getAlignment() << "\n";
cerr << "Expected RegClass size = " << RC->getSize()
<< ", align = " << RC->getAlignment() << "\n";
#endif
cerr << "Fatal error, aborting.\n";
abort();
}
}
} else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateImm(C->getValue()));
} else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) {
const Type *FType = MVT::getTypeForValueType(Op.getValueType());
ConstantFP *CFP = ConstantFP::get(FType, F->getValueAPF());
MI->addOperand(MachineOperand::CreateFPImm(CFP));
} else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateReg(R->getReg(), false));
} else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateGA(TGA->getGlobal(),TGA->getOffset()));
} else if (BasicBlockSDNode *BB = dyn_cast<BasicBlockSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateMBB(BB->getBasicBlock()));
} else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateFI(FI->getIndex()));
} else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateJTI(JT->getIndex()));
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) {
int Offset = CP->getOffset();
unsigned Align = CP->getAlignment();
const Type *Type = CP->getType();
// MachineConstantPool wants an explicit alignment.
if (Align == 0) {
Align = TM.getTargetData()->getPreferredTypeAlignmentShift(Type);
if (Align == 0) {
// Alignment of vector types. FIXME!
Align = TM.getTargetData()->getABITypeSize(Type);
Align = Log2_64(Align);
}
}
unsigned Idx;
if (CP->isMachineConstantPoolEntry())
Idx = ConstPool->getConstantPoolIndex(CP->getMachineCPVal(), Align);
else
Idx = ConstPool->getConstantPoolIndex(CP->getConstVal(), Align);
MI->addOperand(MachineOperand::CreateCPI(Idx, Offset));
} else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateES(ES->getSymbol()));
} else {
assert(Op.getValueType() != MVT::Other &&
Op.getValueType() != MVT::Flag &&
"Chain and flag operands should occur at end of operand list!");
unsigned VReg = getVR(Op, VRBaseMap);
MI->addOperand(MachineOperand::CreateReg(VReg, false));
// Verify that it is right.
assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
if (II) {
const TargetRegisterClass *RC =
getInstrOperandRegClass(TRI, TII, *II, IIOpNum);
assert(RC && "Don't have operand info for this instruction!");
assert(RegInfo.getRegClass(VReg) == RC &&
"Register class of operand and regclass of use don't agree!");
}
}
}
void ScheduleDAG::AddMemOperand(MachineInstr *MI, const MemOperand &MO) {
MI->addMemOperand(MO);
}
// Returns the Register Class of a subregister
static const TargetRegisterClass *getSubRegisterRegClass(
const TargetRegisterClass *TRC,
unsigned SubIdx) {
// Pick the register class of the subregister
TargetRegisterInfo::regclass_iterator I =
TRC->subregclasses_begin() + SubIdx-1;
assert(I < TRC->subregclasses_end() &&
"Invalid subregister index for register class");
return *I;
}
static const TargetRegisterClass *getSuperregRegisterClass(
const TargetRegisterClass *TRC,
unsigned SubIdx,
MVT::ValueType VT) {
// Pick the register class of the superegister for this type
for (TargetRegisterInfo::regclass_iterator I = TRC->superregclasses_begin(),
E = TRC->superregclasses_end(); I != E; ++I)
if ((*I)->hasType(VT) && getSubRegisterRegClass(*I, SubIdx) == TRC)
return *I;
assert(false && "Couldn't find the register class");
return 0;
}
/// EmitSubregNode - Generate machine code for subreg nodes.
///
void ScheduleDAG::EmitSubregNode(SDNode *Node,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
unsigned VRBase = 0;
unsigned Opc = Node->getTargetOpcode();
if (Opc == TargetInstrInfo::EXTRACT_SUBREG) {
// If the node is only used by a CopyToReg and the dest reg is a vreg, use
// the CopyToReg'd destination register instead of creating a new vreg.
for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
UI != E; ++UI) {
SDNode *Use = *UI;
if (Use->getOpcode() == ISD::CopyToReg &&
Use->getOperand(2).Val == Node) {
unsigned DestReg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
VRBase = DestReg;
break;
}
}
}
unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getValue();
// TODO: If the node is a use of a CopyFromReg from a physical register
// fold the extract into the copy now
// Create the extract_subreg machine instruction.
MachineInstr *MI =
new MachineInstr(BB, TII->get(TargetInstrInfo::EXTRACT_SUBREG));
// Figure out the register class to create for the destreg.
unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
const TargetRegisterClass *TRC = RegInfo.getRegClass(VReg);
const TargetRegisterClass *SRC = getSubRegisterRegClass(TRC, SubIdx);
if (VRBase) {
// Grab the destination register
const TargetRegisterClass *DRC = 0;
DRC = RegInfo.getRegClass(VRBase);
assert(SRC && DRC && SRC == DRC &&
"Source subregister and destination must have the same class");
} else {
// Create the reg
assert(SRC && "Couldn't find source register class");
VRBase = RegInfo.createVirtualRegister(SRC);
}
// Add def, source, and subreg index
MI->addOperand(MachineOperand::CreateReg(VRBase, true));
AddOperand(MI, Node->getOperand(0), 0, 0, VRBaseMap);
MI->addOperand(MachineOperand::CreateImm(SubIdx));
} else if (Opc == TargetInstrInfo::INSERT_SUBREG) {
assert((Node->getNumOperands() == 2 || Node->getNumOperands() == 3) &&
"Malformed insert_subreg node");
bool isUndefInput = (Node->getNumOperands() == 2);
unsigned SubReg = 0;
unsigned SubIdx = 0;
if (isUndefInput) {
SubReg = getVR(Node->getOperand(0), VRBaseMap);
SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getValue();
} else {
SubReg = getVR(Node->getOperand(1), VRBaseMap);
SubIdx = cast<ConstantSDNode>(Node->getOperand(2))->getValue();
}
// TODO: Add tracking info to MachineRegisterInfo of which vregs are subregs
// to allow coalescing in the allocator
// If the node is only used by a CopyToReg and the dest reg is a vreg, use
// the CopyToReg'd destination register instead of creating a new vreg.
// If the CopyToReg'd destination register is physical, then fold the
// insert into the copy
for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end();
UI != E; ++UI) {
SDNode *Use = *UI;
if (Use->getOpcode() == ISD::CopyToReg &&
Use->getOperand(2).Val == Node) {
unsigned DestReg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
if (TargetRegisterInfo::isVirtualRegister(DestReg)) {
VRBase = DestReg;
break;
}
}
}
// Create the insert_subreg machine instruction.
MachineInstr *MI =
new MachineInstr(BB, TII->get(TargetInstrInfo::INSERT_SUBREG));
// Figure out the register class to create for the destreg.
const TargetRegisterClass *TRC = 0;
if (VRBase) {
TRC = RegInfo.getRegClass(VRBase);
} else {
TRC = getSuperregRegisterClass(RegInfo.getRegClass(SubReg), SubIdx,
Node->getValueType(0));
assert(TRC && "Couldn't determine register class for insert_subreg");
VRBase = RegInfo.createVirtualRegister(TRC); // Create the reg
}
MI->addOperand(MachineOperand::CreateReg(VRBase, true));
AddOperand(MI, Node->getOperand(0), 0, 0, VRBaseMap);
if (!isUndefInput)
AddOperand(MI, Node->getOperand(1), 0, 0, VRBaseMap);
MI->addOperand(MachineOperand::CreateImm(SubIdx));
} else
assert(0 && "Node is not a subreg insert or extract");
bool isNew = VRBaseMap.insert(std::make_pair(SDOperand(Node,0), VRBase));
assert(isNew && "Node emitted out of order - early");
}
/// EmitNode - Generate machine code for an node and needed dependencies.
///
void ScheduleDAG::EmitNode(SDNode *Node, unsigned InstanceNo,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
// If machine instruction
if (Node->isTargetOpcode()) {
unsigned Opc = Node->getTargetOpcode();
// Handle subreg insert/extract specially
if (Opc == TargetInstrInfo::EXTRACT_SUBREG ||
Opc == TargetInstrInfo::INSERT_SUBREG) {
EmitSubregNode(Node, VRBaseMap);
return;
}
const TargetInstrDesc &II = TII->get(Opc);
unsigned NumResults = CountResults(Node);
unsigned NodeOperands = CountOperands(Node);
unsigned NodeMemOperands = CountMemOperands(Node);
unsigned NumMIOperands = NodeOperands + NumResults;
bool HasPhysRegOuts = (NumResults > II.getNumDefs()) &&
II.getImplicitDefs() != 0;
#ifndef NDEBUG
assert((II.getNumOperands() == NumMIOperands ||
HasPhysRegOuts || II.isVariadic()) &&
"#operands for dag node doesn't match .td file!");
#endif
// Create the new machine instruction.
MachineInstr *MI = new MachineInstr(II);
// Add result register values for things that are defined by this
// instruction.
if (NumResults)
CreateVirtualRegisters(Node, MI, II, VRBaseMap);
// Emit all of the actual operands of this instruction, adding them to the
// instruction as appropriate.
for (unsigned i = 0; i != NodeOperands; ++i)
AddOperand(MI, Node->getOperand(i), i+II.getNumDefs(), &II, VRBaseMap);
// Emit all of the memory operands of this instruction
for (unsigned i = NodeOperands; i != NodeMemOperands; ++i)
AddMemOperand(MI, cast<MemOperandSDNode>(Node->getOperand(i))->MO);
// Commute node if it has been determined to be profitable.
if (CommuteSet.count(Node)) {
MachineInstr *NewMI = TII->commuteInstruction(MI);
if (NewMI == 0)
DOUT << "Sched: COMMUTING FAILED!\n";
else {
DOUT << "Sched: COMMUTED TO: " << *NewMI;
if (MI != NewMI) {
delete MI;
MI = NewMI;
}
}
}
if (II.usesCustomDAGSchedInsertionHook())
// Insert this instruction into the basic block using a target
// specific inserter which may returns a new basic block.
BB = DAG.getTargetLoweringInfo().EmitInstrWithCustomInserter(MI, BB);
else
BB->push_back(MI);
// Additional results must be an physical register def.
if (HasPhysRegOuts) {
for (unsigned i = II.getNumDefs(); i < NumResults; ++i) {
unsigned Reg = II.getImplicitDefs()[i - II.getNumDefs()];
if (Node->hasAnyUseOfValue(i))
EmitCopyFromReg(Node, i, InstanceNo, Reg, VRBaseMap);
}
}
} else {
switch (Node->getOpcode()) {
default:
#ifndef NDEBUG
Node->dump(&DAG);
#endif
assert(0 && "This target-independent node should have been selected!");
case ISD::EntryToken: // fall thru
case ISD::TokenFactor:
case ISD::LABEL:
case ISD::DECLARE:
case ISD::SRCVALUE:
break;
case ISD::CopyToReg: {
unsigned InReg;
if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(2)))
InReg = R->getReg();
else
InReg = getVR(Node->getOperand(2), VRBaseMap);
unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
if (InReg != DestReg) {// Coalesced away the copy?
const TargetRegisterClass *TRC = 0;
// Get the target register class
if (TargetRegisterInfo::isVirtualRegister(InReg))
TRC = RegInfo.getRegClass(InReg);
else
TRC =
TRI->getPhysicalRegisterRegClass(Node->getOperand(2).getValueType(),
InReg);
TII->copyRegToReg(*BB, BB->end(), DestReg, InReg, TRC, TRC);
}
break;
}
case ISD::CopyFromReg: {
unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
EmitCopyFromReg(Node, 0, InstanceNo, SrcReg, VRBaseMap);
break;
}
case ISD::INLINEASM: {
unsigned NumOps = Node->getNumOperands();
if (Node->getOperand(NumOps-1).getValueType() == MVT::Flag)
--NumOps; // Ignore the flag operand.
// Create the inline asm machine instruction.
MachineInstr *MI =
new MachineInstr(BB, TII->get(TargetInstrInfo::INLINEASM));
// Add the asm string as an external symbol operand.
const char *AsmStr =
cast<ExternalSymbolSDNode>(Node->getOperand(1))->getSymbol();
MI->addOperand(MachineOperand::CreateES(AsmStr));
// Add all of the operand registers to the instruction.
for (unsigned i = 2; i != NumOps;) {
unsigned Flags = cast<ConstantSDNode>(Node->getOperand(i))->getValue();
unsigned NumVals = Flags >> 3;
MI->addOperand(MachineOperand::CreateImm(Flags));
++i; // Skip the ID value.
switch (Flags & 7) {
default: assert(0 && "Bad flags!");
case 1: // Use of register.
for (; NumVals; --NumVals, ++i) {
unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
MI->addOperand(MachineOperand::CreateReg(Reg, false));
}
break;
case 2: // Def of register.
for (; NumVals; --NumVals, ++i) {
unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
MI->addOperand(MachineOperand::CreateReg(Reg, true));
}
break;
case 3: { // Immediate.
for (; NumVals; --NumVals, ++i) {
if (ConstantSDNode *CS =
dyn_cast<ConstantSDNode>(Node->getOperand(i))) {
MI->addOperand(MachineOperand::CreateImm(CS->getValue()));
} else if (GlobalAddressSDNode *GA =
dyn_cast<GlobalAddressSDNode>(Node->getOperand(i))) {
MI->addOperand(MachineOperand::CreateGA(GA->getGlobal(),
GA->getOffset()));
} else {
BasicBlockSDNode *BB =cast<BasicBlockSDNode>(Node->getOperand(i));
MI->addOperand(MachineOperand::CreateMBB(BB->getBasicBlock()));
}
}
break;
}
case 4: // Addressing mode.
// The addressing mode has been selected, just add all of the
// operands to the machine instruction.
for (; NumVals; --NumVals, ++i)
AddOperand(MI, Node->getOperand(i), 0, 0, VRBaseMap);
break;
}
}
break;
}
}
}
}
void ScheduleDAG::EmitNoop() {
TII->insertNoop(*BB, BB->end());
}
void ScheduleDAG::EmitCrossRCCopy(SUnit *SU, DenseMap<SUnit*, unsigned> &VRBaseMap) {
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
if (I->isCtrl) continue; // ignore chain preds
if (!I->Dep->Node) {
// Copy to physical register.
DenseMap<SUnit*, unsigned>::iterator VRI = VRBaseMap.find(I->Dep);
assert(VRI != VRBaseMap.end() && "Node emitted out of order - late");
// Find the destination physical register.
unsigned Reg = 0;
for (SUnit::const_succ_iterator II = SU->Succs.begin(),
EE = SU->Succs.end(); II != EE; ++II) {
if (I->Reg) {
Reg = I->Reg;
break;
}
}
assert(I->Reg && "Unknown physical register!");
TII->copyRegToReg(*BB, BB->end(), Reg, VRI->second,
SU->CopyDstRC, SU->CopySrcRC);
} else {
// Copy from physical register.
assert(I->Reg && "Unknown physical register!");
unsigned VRBase = RegInfo.createVirtualRegister(SU->CopyDstRC);
bool isNew = VRBaseMap.insert(std::make_pair(SU, VRBase));
assert(isNew && "Node emitted out of order - early");
TII->copyRegToReg(*BB, BB->end(), VRBase, I->Reg,
SU->CopyDstRC, SU->CopySrcRC);
}
break;
}
}
/// EmitSchedule - Emit the machine code in scheduled order.
void ScheduleDAG::EmitSchedule() {
// If this is the first basic block in the function, and if it has live ins
// that need to be copied into vregs, emit the copies into the top of the
// block before emitting the code for the block.
if (&MF->front() == BB) {
for (MachineRegisterInfo::livein_iterator LI = RegInfo.livein_begin(),
E = RegInfo.livein_end(); LI != E; ++LI)
if (LI->second) {
const TargetRegisterClass *RC = RegInfo.getRegClass(LI->second);
TII->copyRegToReg(*MF->begin(), MF->begin()->end(), LI->second,
LI->first, RC, RC);
}
}
// Finally, emit the code for all of the scheduled instructions.
DenseMap<SDOperand, unsigned> VRBaseMap;
DenseMap<SUnit*, unsigned> CopyVRBaseMap;
for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
if (SUnit *SU = Sequence[i]) {
for (unsigned j = 0, ee = SU->FlaggedNodes.size(); j != ee; ++j)
EmitNode(SU->FlaggedNodes[j], SU->InstanceNo, VRBaseMap);
if (SU->Node)
EmitNode(SU->Node, SU->InstanceNo, VRBaseMap);
else
EmitCrossRCCopy(SU, CopyVRBaseMap);
} else {
// Null SUnit* is a noop.
EmitNoop();
}
}
}
/// dump - dump the schedule.
void ScheduleDAG::dumpSchedule() const {
for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
if (SUnit *SU = Sequence[i])
SU->dump(&DAG);
else
cerr << "**** NOOP ****\n";
}
}
/// Run - perform scheduling.
///
MachineBasicBlock *ScheduleDAG::Run() {
Schedule();
return BB;
}
/// SUnit - Scheduling unit. It's an wrapper around either a single SDNode or
/// a group of nodes flagged together.
void SUnit::dump(const SelectionDAG *G) const {
cerr << "SU(" << NodeNum << "): ";
if (Node)
Node->dump(G);
else
cerr << "CROSS RC COPY ";
cerr << "\n";
if (FlaggedNodes.size() != 0) {
for (unsigned i = 0, e = FlaggedNodes.size(); i != e; i++) {
cerr << " ";
FlaggedNodes[i]->dump(G);
cerr << "\n";
}
}
}
void SUnit::dumpAll(const SelectionDAG *G) const {
dump(G);
cerr << " # preds left : " << NumPredsLeft << "\n";
cerr << " # succs left : " << NumSuccsLeft << "\n";
cerr << " Latency : " << Latency << "\n";
cerr << " Depth : " << Depth << "\n";
cerr << " Height : " << Height << "\n";
if (Preds.size() != 0) {
cerr << " Predecessors:\n";
for (SUnit::const_succ_iterator I = Preds.begin(), E = Preds.end();
I != E; ++I) {
if (I->isCtrl)
cerr << " ch #";
else
cerr << " val #";
cerr << I->Dep << " - SU(" << I->Dep->NodeNum << ")";
if (I->isSpecial)
cerr << " *";
cerr << "\n";
}
}
if (Succs.size() != 0) {
cerr << " Successors:\n";
for (SUnit::const_succ_iterator I = Succs.begin(), E = Succs.end();
I != E; ++I) {
if (I->isCtrl)
cerr << " ch #";
else
cerr << " val #";
cerr << I->Dep << " - SU(" << I->Dep->NodeNum << ")";
if (I->isSpecial)
cerr << " *";
cerr << "\n";
}
}
cerr << "\n";
}
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