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llvm-6502/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
Dan Gohman e8be6c6391 Add a new function, ReplaceAllUsesOfValuesWith, which handles bulk 
replacement of multiple values. This is slightly more efficient
than doing multiple ReplaceAllUsesOfValueWith calls, and theoretically
could be optimized even further. However, an important property of this
new function is that it handles the case where the source value set and
destination value set overlap. This makes it feasible for isel to use
SelectNodeTo in many very common cases, which is advantageous because
SelectNodeTo avoids a temporary node and it doesn't require CSEMap
updates for users of values that don't change position.

Revamp MorphNodeTo, which is what does all the work of SelectNodeTo, to
handle operand lists more efficiently, and to correctly handle a number
of corner cases to which its new wider use exposes it.

This commit also includes a change to the encoding of post-isel opcodes
in SDNodes; now instead of being sandwiched between the target-independent
pre-isel opcodes and the target-dependent pre-isel opcodes, post-isel
opcodes are now represented as negative values. This makes it possible
to test if an opcode is pre-isel or post-isel without having to know
the size of the current target's post-isel instruction set.

These changes speed up llc overall by 3% and reduce memory usage by 10%
on the InstructionCombining.cpp testcase with -fast and -regalloc=local.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53728 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-17 19:10:17 +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 the ScheduleDAG class, which is a base class used by
// scheduling implementation classes.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "pre-RA-sched"
#include "llvm/Type.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.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/ADT/Statistic.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
STATISTIC(NumCommutes, "Number of instructions commuted");
namespace {
static cl::opt<bool>
SchedLiveInCopies("schedule-livein-copies",
cl::desc("Schedule copies of livein registers"),
cl::init(false));
}
ScheduleDAG::ScheduleDAG(SelectionDAG &dag, MachineBasicBlock *bb,
const TargetMachine &tm)
: DAG(dag), BB(bb), TM(tm), MRI(BB->getParent()->getRegInfo()) {
TII = TM.getInstrInfo();
MF = &DAG.getMachineFunction();
TRI = TM.getRegisterInfo();
TLI = &DAG.getTargetLoweringInfo();
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->isMachineOpcode()) {
const TargetInstrDesc &II = TII->get(Def->getMachineOpcode());
if (ResNo >= II.getNumDefs() &&
II.ImplicitDefs[ResNo - II.getNumDefs()] == Reg) {
PhysReg = Reg;
const TargetRegisterClass *RC =
TRI->getPhysicalRegisterRegClass(Reg, Def->getValueType(ResNo));
Cost = RC->getCopyCost();
}
}
}
SUnit *ScheduleDAG::Clone(SUnit *Old) {
SUnit *SU = NewSUnit(Old->Node);
SU->OrigNode = Old->OrigNode;
SU->FlaggedNodes = Old->FlaggedNodes;
SU->Latency = Old->Latency;
SU->isTwoAddress = Old->isTwoAddress;
SU->isCommutable = Old->isCommutable;
SU->hasPhysRegDefs = Old->hasPhysRegDefs;
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(DAG.allnodes_size());
// During scheduling, the NodeId field of SDNode is used to map SDNodes
// to their associated SUnits by holding SUnits table indices. A value
// of -1 means the SDNode does not yet have an associated SUnit.
for (SelectionDAG::allnodes_iterator NI = DAG.allnodes_begin(),
E = DAG.allnodes_end(); NI != E; ++NI)
NI->setNodeId(-1);
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 (NI->getNodeId() != -1) 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);
assert(N->getNodeId() == -1 && "Node already inserted!");
N->setNodeId(NodeSUnit->NodeNum);
} 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.isOperandOf(UI->getUser())) {
HasFlagUse = true;
NodeSUnit->FlaggedNodes.push_back(N);
assert(N->getNodeId() == -1 && "Node already inserted!");
N->setNodeId(NodeSUnit->NodeNum);
N = UI->getUser();
break;
}
if (!HasFlagUse) break;
}
// Now all flagged nodes are in FlaggedNodes and N is the bottom-most node.
// Update the SUnit
NodeSUnit->Node = N;
assert(N->getNodeId() == -1 && "Node already inserted!");
N->setNodeId(NodeSUnit->NodeNum);
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->isMachineOpcode()) {
unsigned Opc = MainNode->getMachineOpcode();
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->isMachineOpcode() &&
TII->get(N->getMachineOpcode()).getImplicitDefs() &&
CountResults(N) > TII->get(N->getMachineOpcode()).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 = &SUnits[OpN->getNodeId()];
assert(OpSU && "Node has no SUnit!");
if (OpSU == SU) continue; // In the same group.
MVT 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();
}
}
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;
return;
}
SU->Latency = 0;
if (SU->Node->isMachineOpcode()) {
unsigned SchedClass = TII->get(SU->Node->getMachineOpcode()).getSchedClass();
const InstrStage *S = InstrItins.begin(SchedClass);
const 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->isMachineOpcode()) {
unsigned SchedClass = TII->get(FNode->getMachineOpcode()).getSchedClass();
const InstrStage *S = InstrItins.begin(SchedClass);
const InstrStage *E = InstrItins.end(SchedClass);
for (; S != E; ++S)
SU->Latency += S->Cycles;
}
}
}
/// CalculateDepths - compute depths using algorithms for the longest
/// paths in the DAG
void ScheduleDAG::CalculateDepths() {
unsigned DAGSize = SUnits.size();
std::vector<unsigned> InDegree(DAGSize);
std::vector<SUnit*> WorkList;
WorkList.reserve(DAGSize);
// Initialize the data structures
for (unsigned i = 0, e = DAGSize; i != e; ++i) {
SUnit *SU = &SUnits[i];
int NodeNum = SU->NodeNum;
unsigned Degree = SU->Preds.size();
InDegree[NodeNum] = Degree;
SU->Depth = 0;
// Is it a node without dependencies?
if (Degree == 0) {
assert(SU->Preds.empty() && "SUnit should have no predecessors");
// Collect leaf nodes
WorkList.push_back(SU);
}
}
// Process nodes in the topological order
while (!WorkList.empty()) {
SUnit *SU = WorkList.back();
WorkList.pop_back();
unsigned &SUDepth = SU->Depth;
// Use dynamic programming:
// When current node is being processed, all of its dependencies
// are already processed.
// So, just iterate over all predecessors and take the longest path
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
unsigned PredDepth = I->Dep->Depth;
if (PredDepth+1 > SUDepth) {
SUDepth = PredDepth + 1;
}
}
// Update InDegrees of all nodes depending on current SUnit
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
SUnit *SU = I->Dep;
if (!--InDegree[SU->NodeNum])
// If all dependencies of the node are processed already,
// then the longest path for the node can be computed now
WorkList.push_back(SU);
}
}
}
/// CalculateHeights - compute heights using algorithms for the longest
/// paths in the DAG
void ScheduleDAG::CalculateHeights() {
unsigned DAGSize = SUnits.size();
std::vector<unsigned> InDegree(DAGSize);
std::vector<SUnit*> WorkList;
WorkList.reserve(DAGSize);
// Initialize the data structures
for (unsigned i = 0, e = DAGSize; i != e; ++i) {
SUnit *SU = &SUnits[i];
int NodeNum = SU->NodeNum;
unsigned Degree = SU->Succs.size();
InDegree[NodeNum] = Degree;
SU->Height = 0;
// Is it a node without dependencies?
if (Degree == 0) {
assert(SU->Succs.empty() && "Something wrong");
assert(WorkList.empty() && "Should be empty");
// Collect leaf nodes
WorkList.push_back(SU);
}
}
// Process nodes in the topological order
while (!WorkList.empty()) {
SUnit *SU = WorkList.back();
WorkList.pop_back();
unsigned &SUHeight = SU->Height;
// Use dynamic programming:
// When current node is being processed, all of its dependencies
// are already processed.
// So, just iterate over all successors and take the longest path
for (SUnit::const_succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
I != E; ++I) {
unsigned SuccHeight = I->Dep->Height;
if (SuccHeight+1 > SUHeight) {
SUHeight = SuccHeight + 1;
}
}
// Update InDegrees of all nodes depending on current SUnit
for (SUnit::const_pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
I != E; ++I) {
SUnit *SU = I->Dep;
if (!--InDegree[SU->NodeNum])
// If all dependencies of the node are processed already,
// then the longest path for the node can be computed now
WorkList.push_back(SU);
}
}
}
/// 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 special operands that describe memory references, then an
/// optional 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 = ComputeMemOperandsEnd(Node);
while (N && isa<MemOperandSDNode>(Node->getOperand(N - 1).Val))
--N; // Ignore MEMOPERAND nodes
return N;
}
/// ComputeMemOperandsEnd - Find the index one past the last MemOperandSDNode
/// operand
unsigned ScheduleDAG::ComputeMemOperandsEnd(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;
}
/// getInstrOperandRegClass - Return register class of the operand of an
/// instruction of the specified TargetInstrDesc.
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);
}
/// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an
/// implicit physical register output.
void ScheduleDAG::EmitCopyFromReg(SDNode *Node, unsigned ResNo,
bool IsClone, unsigned SrcReg,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
unsigned VRBase = 0;
if (TargetRegisterInfo::isVirtualRegister(SrcReg)) {
// Just use the input register directly!
SDOperand Op(Node, ResNo);
if (IsClone)
VRBaseMap.erase(Op);
bool isNew = VRBaseMap.insert(std::make_pair(Op, SrcReg)).second;
isNew = isNew; // Silence compiler warning.
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->getUser();
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 VT = Node->getValueType(Op.ResNo);
if (VT != MVT::Other && VT != MVT::Flag)
Match = false;
}
}
MatchReg &= Match;
if (VRBase)
break;
}
const TargetRegisterClass *SrcRC = 0, *DstRC = 0;
SrcRC = TRI->getPhysicalRegisterRegClass(SrcReg, Node->getValueType(ResNo));
// Figure out the register class to create for the destreg.
if (VRBase) {
DstRC = MRI.getRegClass(VRBase);
} else {
DstRC = TLI->getRegClassFor(Node->getValueType(ResNo));
}
// 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 && SrcRC->getCopyCost() < 0) {
VRBase = SrcReg;
} else {
// Create the reg, emit the copy.
VRBase = MRI.createVirtualRegister(DstRC);
TII->copyRegToReg(*BB, BB->end(), VRBase, SrcReg, DstRC, SrcRC);
}
SDOperand Op(Node, ResNo);
if (IsClone)
VRBaseMap.erase(Op);
bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
isNew = isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
/// getDstOfCopyToRegUse - If the only use of the specified result number of
/// node is a CopyToReg, return its destination register. Return 0 otherwise.
unsigned ScheduleDAG::getDstOfOnlyCopyToRegUse(SDNode *Node,
unsigned ResNo) const {
if (!Node->hasOneUse())
return 0;
SDNode *Use = Node->use_begin()->getUser();
if (Use->getOpcode() == ISD::CopyToReg &&
Use->getOperand(2).Val == Node &&
Use->getOperand(2).ResNo == ResNo) {
unsigned Reg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
if (TargetRegisterInfo::isVirtualRegister(Reg))
return Reg;
}
return 0;
}
void ScheduleDAG::CreateVirtualRegisters(SDNode *Node, MachineInstr *MI,
const TargetInstrDesc &II,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
assert(Node->getMachineOpcode() != TargetInstrInfo::IMPLICIT_DEF &&
"IMPLICIT_DEF should have been handled as a special case elsewhere!");
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->getUser();
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 = MRI.createVirtualRegister(RC);
MI->addOperand(MachineOperand::CreateReg(VRBase, true));
}
SDOperand Op(Node, i);
bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
isNew = isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
}
/// getVR - Return the virtual register corresponding to the specified result
/// of the specified node.
unsigned ScheduleDAG::getVR(SDOperand Op,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
if (Op.isMachineOpcode() &&
Op.getMachineOpcode() == TargetInstrInfo::IMPLICIT_DEF) {
// Add an IMPLICIT_DEF instruction before every use.
unsigned VReg = getDstOfOnlyCopyToRegUse(Op.Val, Op.ResNo);
// IMPLICIT_DEF can produce any type of result so its TargetInstrDesc
// does not include operand register class info.
if (!VReg) {
const TargetRegisterClass *RC = TLI->getRegClassFor(Op.getValueType());
VReg = MRI.createVirtualRegister(RC);
}
BuildMI(BB, TII->get(TargetInstrInfo::IMPLICIT_DEF), VReg);
return VReg;
}
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.isMachineOpcode()) {
// 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();
MI->addOperand(MachineOperand::CreateReg(VReg, isOptDef));
// Verify that it is right.
assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
#ifndef NDEBUG
if (II) {
// There may be no register class for this operand if it is a variadic
// argument (RC will be NULL in this case). In this case, we just assume
// the regclass is ok.
const TargetRegisterClass *RC =
getInstrOperandRegClass(TRI, TII, *II, IIOpNum);
assert((RC || II->isVariadic()) && "Expected reg class info!");
const TargetRegisterClass *VRC = MRI.getRegClass(VReg);
if (RC && VRC != RC) {
cerr << "Register class of operand and regclass of use don't agree!\n";
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";
cerr << "Fatal error, aborting.\n";
abort();
}
}
#endif
} else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
MI->addOperand(MachineOperand::CreateImm(C->getValue()));
} else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) {
ConstantFP *CFP = ConstantFP::get(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. Note that the reg class of the physreg and the
// vreg don't necessarily need to match, but the target copy insertion has
// to be able to handle it. This handles things like copies from ST(0) to
// an FP vreg on x86.
assert(TargetRegisterInfo::isVirtualRegister(VReg) && "Not a vreg?");
if (II && !II->isVariadic()) {
assert(getInstrOperandRegClass(TRI, TII, *II, IIOpNum) &&
"Don't have operand info for this instruction!");
}
}
}
void ScheduleDAG::AddMemOperand(MachineInstr *MI, const MachineMemOperand &MO) {
MI->addMemOperand(*MF, MO);
}
/// getSubRegisterRegClass - Returns the register class of specified register
/// class' "SubIdx"'th sub-register class.
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;
}
/// getSuperRegisterRegClass - Returns the register class of a superreg A whose
/// "SubIdx"'th sub-register class is the specified register class and whose
/// type matches the specified type.
static const TargetRegisterClass*
getSuperRegisterRegClass(const TargetRegisterClass *TRC,
unsigned SubIdx, MVT 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->getMachineOpcode();
// 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->getUser();
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;
}
}
}
if (Opc == TargetInstrInfo::EXTRACT_SUBREG) {
unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getValue();
// Create the extract_subreg machine instruction.
MachineInstr *MI = BuildMI(*MF, 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 = MRI.getRegClass(VReg);
const TargetRegisterClass *SRC = getSubRegisterRegClass(TRC, SubIdx);
if (VRBase) {
// Grab the destination register
#ifndef NDEBUG
const TargetRegisterClass *DRC = MRI.getRegClass(VRBase);
assert(SRC && DRC && SRC == DRC &&
"Source subregister and destination must have the same class");
#endif
} else {
// Create the reg
assert(SRC && "Couldn't find source register class");
VRBase = MRI.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));
BB->push_back(MI);
} else if (Opc == TargetInstrInfo::INSERT_SUBREG ||
Opc == TargetInstrInfo::SUBREG_TO_REG) {
SDOperand N0 = Node->getOperand(0);
SDOperand N1 = Node->getOperand(1);
SDOperand N2 = Node->getOperand(2);
unsigned SubReg = getVR(N1, VRBaseMap);
unsigned SubIdx = cast<ConstantSDNode>(N2)->getValue();
// Figure out the register class to create for the destreg.
const TargetRegisterClass *TRC = 0;
if (VRBase) {
TRC = MRI.getRegClass(VRBase);
} else {
TRC = getSuperRegisterRegClass(MRI.getRegClass(SubReg), SubIdx,
Node->getValueType(0));
assert(TRC && "Couldn't determine register class for insert_subreg");
VRBase = MRI.createVirtualRegister(TRC); // Create the reg
}
// Create the insert_subreg or subreg_to_reg machine instruction.
MachineInstr *MI = BuildMI(*MF, TII->get(Opc));
MI->addOperand(MachineOperand::CreateReg(VRBase, true));
// If creating a subreg_to_reg, then the first input operand
// is an implicit value immediate, otherwise it's a register
if (Opc == TargetInstrInfo::SUBREG_TO_REG) {
const ConstantSDNode *SD = cast<ConstantSDNode>(N0);
MI->addOperand(MachineOperand::CreateImm(SD->getValue()));
} else
AddOperand(MI, N0, 0, 0, VRBaseMap);
// Add the subregster being inserted
AddOperand(MI, N1, 0, 0, VRBaseMap);
MI->addOperand(MachineOperand::CreateImm(SubIdx));
BB->push_back(MI);
} else
assert(0 && "Node is not insert_subreg, extract_subreg, or subreg_to_reg");
SDOperand Op(Node, 0);
bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
isNew = isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
/// EmitNode - Generate machine code for an node and needed dependencies.
///
void ScheduleDAG::EmitNode(SDNode *Node, bool IsClone,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
// If machine instruction
if (Node->isMachineOpcode()) {
unsigned Opc = Node->getMachineOpcode();
// Handle subreg insert/extract specially
if (Opc == TargetInstrInfo::EXTRACT_SUBREG ||
Opc == TargetInstrInfo::INSERT_SUBREG ||
Opc == TargetInstrInfo::SUBREG_TO_REG) {
EmitSubregNode(Node, VRBaseMap);
return;
}
if (Opc == TargetInstrInfo::IMPLICIT_DEF)
// We want a unique VR for each IMPLICIT_DEF use.
return;
const TargetInstrDesc &II = TII->get(Opc);
unsigned NumResults = CountResults(Node);
unsigned NodeOperands = CountOperands(Node);
unsigned MemOperandsEnd = ComputeMemOperandsEnd(Node);
bool HasPhysRegOuts = (NumResults > II.getNumDefs()) &&
II.getImplicitDefs() != 0;
#ifndef NDEBUG
unsigned NumMIOperands = NodeOperands + NumResults;
assert((II.getNumOperands() == NumMIOperands ||
HasPhysRegOuts || II.isVariadic()) &&
"#operands for dag node doesn't match .td file!");
#endif
// Create the new machine instruction.
MachineInstr *MI = BuildMI(*MF, 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 != MemOperandsEnd; ++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) {
MF->DeleteMachineInstr(MI);
MI = NewMI;
}
++NumCommutes;
}
}
if (II.usesCustomDAGSchedInsertionHook())
// Insert this instruction into the basic block using a target
// specific inserter which may returns a new basic block.
BB = TLI->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, IsClone, Reg, VRBaseMap);
}
}
return;
}
switch (Node->getOpcode()) {
default:
#ifndef NDEBUG
Node->dump(&DAG);
#endif
assert(0 && "This target-independent node should have been selected!");
break;
case ISD::EntryToken:
assert(0 && "EntryToken should have been excluded from the schedule!");
break;
case ISD::TokenFactor: // fall thru
break;
case ISD::CopyToReg: {
unsigned SrcReg;
SDOperand SrcVal = Node->getOperand(2);
if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal))
SrcReg = R->getReg();
else
SrcReg = getVR(SrcVal, VRBaseMap);
unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
if (SrcReg == DestReg) // Coalesced away the copy? Ignore.
break;
const TargetRegisterClass *SrcTRC = 0, *DstTRC = 0;
// Get the register classes of the src/dst.
if (TargetRegisterInfo::isVirtualRegister(SrcReg))
SrcTRC = MRI.getRegClass(SrcReg);
else
SrcTRC = TRI->getPhysicalRegisterRegClass(SrcReg,SrcVal.getValueType());
if (TargetRegisterInfo::isVirtualRegister(DestReg))
DstTRC = MRI.getRegClass(DestReg);
else
DstTRC = TRI->getPhysicalRegisterRegClass(DestReg,
Node->getOperand(1).getValueType());
TII->copyRegToReg(*BB, BB->end(), DestReg, SrcReg, DstTRC, SrcTRC);
break;
}
case ISD::CopyFromReg: {
unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
EmitCopyFromReg(Node, 0, IsClone, 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 = BuildMI(*MF, 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 2: // Def of register.
for (; NumVals; --NumVals, ++i) {
unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
MI->addOperand(MachineOperand::CreateReg(Reg, true));
}
break;
case 1: // Use of register.
case 3: // Immediate.
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;
}
}
BB->push_back(MI);
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 = MRI.createVirtualRegister(SU->CopyDstRC);
bool isNew = VRBaseMap.insert(std::make_pair(SU, VRBase)).second;
isNew = isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
TII->copyRegToReg(*BB, BB->end(), VRBase, I->Reg,
SU->CopyDstRC, SU->CopySrcRC);
}
break;
}
}
/// EmitLiveInCopy - Emit a copy for a live in physical register. If the
/// physical register has only a single copy use, then coalesced the copy
/// if possible.
void ScheduleDAG::EmitLiveInCopy(MachineBasicBlock *MBB,
MachineBasicBlock::iterator &InsertPos,
unsigned VirtReg, unsigned PhysReg,
const TargetRegisterClass *RC,
DenseMap<MachineInstr*, unsigned> &CopyRegMap){
unsigned NumUses = 0;
MachineInstr *UseMI = NULL;
for (MachineRegisterInfo::use_iterator UI = MRI.use_begin(VirtReg),
UE = MRI.use_end(); UI != UE; ++UI) {
UseMI = &*UI;
if (++NumUses > 1)
break;
}
// If the number of uses is not one, or the use is not a move instruction,
// don't coalesce. Also, only coalesce away a virtual register to virtual
// register copy.
bool Coalesced = false;
unsigned SrcReg, DstReg;
if (NumUses == 1 &&
TII->isMoveInstr(*UseMI, SrcReg, DstReg) &&
TargetRegisterInfo::isVirtualRegister(DstReg)) {
VirtReg = DstReg;
Coalesced = true;
}
// Now find an ideal location to insert the copy.
MachineBasicBlock::iterator Pos = InsertPos;
while (Pos != MBB->begin()) {
MachineInstr *PrevMI = prior(Pos);
DenseMap<MachineInstr*, unsigned>::iterator RI = CopyRegMap.find(PrevMI);
// copyRegToReg might emit multiple instructions to do a copy.
unsigned CopyDstReg = (RI == CopyRegMap.end()) ? 0 : RI->second;
if (CopyDstReg && !TRI->regsOverlap(CopyDstReg, PhysReg))
// This is what the BB looks like right now:
// r1024 = mov r0
// ...
// r1 = mov r1024
//
// We want to insert "r1025 = mov r1". Inserting this copy below the
// move to r1024 makes it impossible for that move to be coalesced.
//
// r1025 = mov r1
// r1024 = mov r0
// ...
// r1 = mov 1024
// r2 = mov 1025
break; // Woot! Found a good location.
--Pos;
}
TII->copyRegToReg(*MBB, Pos, VirtReg, PhysReg, RC, RC);
CopyRegMap.insert(std::make_pair(prior(Pos), VirtReg));
if (Coalesced) {
if (&*InsertPos == UseMI) ++InsertPos;
MBB->erase(UseMI);
}
}
/// EmitLiveInCopies - 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.
void ScheduleDAG::EmitLiveInCopies(MachineBasicBlock *MBB) {
DenseMap<MachineInstr*, unsigned> CopyRegMap;
MachineBasicBlock::iterator InsertPos = MBB->begin();
for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(),
E = MRI.livein_end(); LI != E; ++LI)
if (LI->second) {
const TargetRegisterClass *RC = MRI.getRegClass(LI->second);
EmitLiveInCopy(MBB, InsertPos, LI->second, LI->first, RC, CopyRegMap);
}
}
/// EmitSchedule - Emit the machine code in scheduled order.
MachineBasicBlock *ScheduleDAG::EmitSchedule() {
bool isEntryBB = &MF->front() == BB;
if (isEntryBB && !SchedLiveInCopies) {
// 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.
for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(),
E = MRI.livein_end(); LI != E; ++LI)
if (LI->second) {
const TargetRegisterClass *RC = MRI.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++) {
SUnit *SU = Sequence[i];
if (!SU) {
// Null SUnit* is a noop.
EmitNoop();
continue;
}
for (unsigned j = 0, ee = SU->FlaggedNodes.size(); j != ee; ++j)
EmitNode(SU->FlaggedNodes[j], SU->OrigNode != SU, VRBaseMap);
if (!SU->Node)
EmitCrossRCCopy(SU, CopyVRBaseMap);
else
EmitNode(SU->Node, SU->OrigNode != SU, VRBaseMap);
}
if (isEntryBB && SchedLiveInCopies)
EmitLiveInCopies(MF->begin());
return BB;
}
/// 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.
///
void ScheduleDAG::Run() {
Schedule();
DOUT << "*** Final schedule ***\n";
DEBUG(dumpSchedule());
DOUT << "\n";
}
/// 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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