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When a node value is only used by a CopyToReg, use the user's dest. This should not be restricted to nodes that produce only a single value.

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llvm-svn: 38485
This commit is contained in:
Evan Cheng 2007-07-10 07:08:32 +00:00
parent 23dc96f640
commit cf3b1c89a9
3 changed files with 58 additions and 53 deletions
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4
include/llvm/CodeGen/ScheduleDAG.h
View File

@ -240,7 +240,7 @@ namespace llvm {
/// VRBaseMap contains, for each already emitted node, the first virtual
/// register number for the results of the node.
///
void EmitNode(SDNode *Node, DenseMap<SDNode*, unsigned> &VRBaseMap);
void EmitNode(SDNode *Node, DenseMap<SDOperand, unsigned> &VRBaseMap);
/// EmitNoop - Emit a noop instruction.
///
@ -257,7 +257,7 @@ namespace llvm {
private:
void AddOperand(MachineInstr *MI, SDOperand Op, unsigned IIOpNum,
const TargetInstrDescriptor *II,
DenseMap<SDNode*, unsigned> &VRBaseMap);
DenseMap<SDOperand, unsigned> &VRBaseMap);
};
/// createBFS_DAGScheduler - This creates a simple breadth first instruction

91
lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
View File

@ -254,31 +254,54 @@ static const TargetRegisterClass *getInstrOperandRegClass(
? TII->getPointerRegClass() : MRI->getRegClass(toi.RegClass);
}
static unsigned CreateVirtualRegisters(const MRegisterInfo *MRI,
MachineInstr *MI,
static void CreateVirtualRegisters(SDNode *Node,
unsigned NumResults,
const MRegisterInfo *MRI,
MachineInstr *MI,
SSARegMap *RegMap,
const TargetInstrInfo *TII,
const TargetInstrDescriptor &II) {
const TargetInstrDescriptor &II,
DenseMap<SDOperand, unsigned> &VRBaseMap) {
for (unsigned i = 0; i < NumResults; ++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 (MRegisterInfo::isVirtualRegister(Reg)) {
VRBase = Reg;
MI->addRegOperand(Reg, true);
break;
}
}
}
if (VRBase == 0) {
// Create the result registers for this node and add the result regs to
// the machine instruction.
unsigned ResultReg =
RegMap->createVirtualRegister(getInstrOperandRegClass(MRI, TII, &II, 0));
MI->addRegOperand(ResultReg, true);
for (unsigned i = 1; i != NumResults; ++i) {
const TargetRegisterClass *RC = getInstrOperandRegClass(MRI, TII, &II, i);
assert(RC && "Isn't a register operand!");
MI->addRegOperand(RegMap->createVirtualRegister(RC), true);
VRBase = RegMap->createVirtualRegister(RC);
MI->addRegOperand(VRBase, true);
}
bool isNew = VRBaseMap.insert(std::make_pair(SDOperand(Node,i), VRBase));
assert(isNew && "Node emitted out of order - early");
}
return ResultReg;
}
/// getVR - Return the virtual register corresponding to the specified result
/// of the specified node.
static unsigned getVR(SDOperand Op, DenseMap<SDNode*, unsigned> &VRBaseMap) {
DenseMap<SDNode*, unsigned>::iterator I = VRBaseMap.find(Op.Val);
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 + Op.ResNo;
return I->second;
}
@ -289,7 +312,7 @@ static unsigned getVR(SDOperand Op, DenseMap<SDNode*, unsigned> &VRBaseMap) {
void ScheduleDAG::AddOperand(MachineInstr *MI, SDOperand Op,
unsigned IIOpNum,
const TargetInstrDescriptor *II,
DenseMap<SDNode*, unsigned> &VRBaseMap) {
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
@ -406,9 +429,7 @@ static const TargetRegisterClass *getPhysicalRegisterRegClass(
/// EmitNode - Generate machine code for an node and needed dependencies.
///
void ScheduleDAG::EmitNode(SDNode *Node,
DenseMap<SDNode*, unsigned> &VRBaseMap) {
unsigned VRBase = 0; // First virtual register for node
DenseMap<SDOperand, unsigned> &VRBaseMap) {
// If machine instruction
if (Node->isTargetOpcode()) {
unsigned Opc = Node->getTargetOpcode();
@ -428,28 +449,9 @@ void ScheduleDAG::EmitNode(SDNode *Node,
// Add result register values for things that are defined by this
// instruction.
// 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 (NumResults == 1) {
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 Reg = cast<RegisterSDNode>(Use->getOperand(1))->getReg();
if (MRegisterInfo::isVirtualRegister(Reg)) {
VRBase = Reg;
MI->addRegOperand(Reg, true);
break;
}
}
}
}
// Otherwise, create new virtual registers.
if (NumResults && VRBase == 0)
VRBase = CreateVirtualRegisters(MRI, MI, NumResults, RegMap, TII, II);
if (NumResults)
CreateVirtualRegisters(Node, NumResults, MRI, MI, RegMap,
TII, II, VRBaseMap);
// Emit all of the actual operands of this instruction, adding them to the
// instruction as appropriate.
@ -510,9 +512,12 @@ void ScheduleDAG::EmitNode(SDNode *Node,
break;
}
case ISD::CopyFromReg: {
unsigned VRBase = 0;
unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
if (MRegisterInfo::isVirtualRegister(SrcReg)) {
VRBase = SrcReg; // Just use the input register directly!
// Just use the input register directly!
bool isNew = VRBaseMap.insert(std::make_pair(SDOperand(Node,0),SrcReg));
assert(isNew && "Node emitted out of order - early");
break;
}
@ -542,6 +547,9 @@ void ScheduleDAG::EmitNode(SDNode *Node,
VRBase = RegMap->createVirtualRegister(TRC);
}
MRI->copyRegToReg(*BB, BB->end(), VRBase, SrcReg, TRC);
bool isNew = VRBaseMap.insert(std::make_pair(SDOperand(Node,0), VRBase));
assert(isNew && "Node emitted out of order - early");
break;
}
case ISD::INLINEASM: {
@ -604,9 +612,6 @@ void ScheduleDAG::EmitNode(SDNode *Node,
}
}
}
assert(!VRBaseMap.count(Node) && "Node emitted out of order - early");
VRBaseMap[Node] = VRBase;
}
void ScheduleDAG::EmitNoop() {
@ -629,7 +634,7 @@ void ScheduleDAG::EmitSchedule() {
// Finally, emit the code for all of the scheduled instructions.
DenseMap<SDNode*, unsigned> VRBaseMap;
DenseMap<SDOperand, unsigned> VRBaseMap;
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++)

2
lib/CodeGen/SelectionDAG/ScheduleDAGSimple.cpp
View File

@ -682,7 +682,7 @@ void ScheduleDAGSimple::EmitAll() {
LI->first, RegMap->getRegClass(LI->second));
}
DenseMap<SDNode*, unsigned> VRBaseMap;
DenseMap<SDOperand, unsigned> VRBaseMap;
// For each node in the ordering
for (unsigned i = 0, N = Ordering.size(); i < N; i++) {