llvm-6502/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
Tim Northover 3e84ad28d4 ISelDAG: spot chain cycles involving MachineNodes
Previously, the DAGISel function WalkChainUsers was spotting that it
had entered already-selected territory by whether a node was a
MachineNode (amongst other things). Since it's fairly common practice
to insert MachineNodes during ISelLowering, this was not the correct
check.

Looking around, it seems that other nodes get their NodeId set to -1
upon selection, so this makes sure the same thing happens to all
MachineNodes and uses that characteristic to determine whether we
should stop looking for a loop during selection.

This should fix PR15840.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191165 91177308-0d34-0410-b5e6-96231b3b80d8
2013-09-22 08:21:56 +00:00

495 lines
15 KiB
C++

//===-- MSP430ISelDAGToDAG.cpp - A dag to dag inst selector for MSP430 ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines an instruction selector for the MSP430 target.
//
//===----------------------------------------------------------------------===//
#include "MSP430.h"
#include "MSP430TargetMachine.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetLowering.h"
using namespace llvm;
namespace {
struct MSP430ISelAddressMode {
enum {
RegBase,
FrameIndexBase
} BaseType;
struct { // This is really a union, discriminated by BaseType!
SDValue Reg;
int FrameIndex;
} Base;
int16_t Disp;
const GlobalValue *GV;
const Constant *CP;
const BlockAddress *BlockAddr;
const char *ES;
int JT;
unsigned Align; // CP alignment.
MSP430ISelAddressMode()
: BaseType(RegBase), Disp(0), GV(0), CP(0), BlockAddr(0),
ES(0), JT(-1), Align(0) {
}
bool hasSymbolicDisplacement() const {
return GV != 0 || CP != 0 || ES != 0 || JT != -1;
}
void dump() {
errs() << "MSP430ISelAddressMode " << this << '\n';
if (BaseType == RegBase && Base.Reg.getNode() != 0) {
errs() << "Base.Reg ";
Base.Reg.getNode()->dump();
} else if (BaseType == FrameIndexBase) {
errs() << " Base.FrameIndex " << Base.FrameIndex << '\n';
}
errs() << " Disp " << Disp << '\n';
if (GV) {
errs() << "GV ";
GV->dump();
} else if (CP) {
errs() << " CP ";
CP->dump();
errs() << " Align" << Align << '\n';
} else if (ES) {
errs() << "ES ";
errs() << ES << '\n';
} else if (JT != -1)
errs() << " JT" << JT << " Align" << Align << '\n';
}
};
}
/// MSP430DAGToDAGISel - MSP430 specific code to select MSP430 machine
/// instructions for SelectionDAG operations.
///
namespace {
class MSP430DAGToDAGISel : public SelectionDAGISel {
const MSP430TargetLowering &Lowering;
const MSP430Subtarget &Subtarget;
public:
MSP430DAGToDAGISel(MSP430TargetMachine &TM, CodeGenOpt::Level OptLevel)
: SelectionDAGISel(TM, OptLevel),
Lowering(*TM.getTargetLowering()),
Subtarget(*TM.getSubtargetImpl()) { }
virtual const char *getPassName() const {
return "MSP430 DAG->DAG Pattern Instruction Selection";
}
bool MatchAddress(SDValue N, MSP430ISelAddressMode &AM);
bool MatchWrapper(SDValue N, MSP430ISelAddressMode &AM);
bool MatchAddressBase(SDValue N, MSP430ISelAddressMode &AM);
virtual bool
SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
std::vector<SDValue> &OutOps);
// Include the pieces autogenerated from the target description.
#include "MSP430GenDAGISel.inc"
private:
SDNode *Select(SDNode *N);
SDNode *SelectIndexedLoad(SDNode *Op);
SDNode *SelectIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2,
unsigned Opc8, unsigned Opc16);
bool SelectAddr(SDValue Addr, SDValue &Base, SDValue &Disp);
};
} // end anonymous namespace
/// createMSP430ISelDag - This pass converts a legalized DAG into a
/// MSP430-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createMSP430ISelDag(MSP430TargetMachine &TM,
CodeGenOpt::Level OptLevel) {
return new MSP430DAGToDAGISel(TM, OptLevel);
}
/// MatchWrapper - Try to match MSP430ISD::Wrapper node into an addressing mode.
/// These wrap things that will resolve down into a symbol reference. If no
/// match is possible, this returns true, otherwise it returns false.
bool MSP430DAGToDAGISel::MatchWrapper(SDValue N, MSP430ISelAddressMode &AM) {
// If the addressing mode already has a symbol as the displacement, we can
// never match another symbol.
if (AM.hasSymbolicDisplacement())
return true;
SDValue N0 = N.getOperand(0);
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
AM.GV = G->getGlobal();
AM.Disp += G->getOffset();
//AM.SymbolFlags = G->getTargetFlags();
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
AM.CP = CP->getConstVal();
AM.Align = CP->getAlignment();
AM.Disp += CP->getOffset();
//AM.SymbolFlags = CP->getTargetFlags();
} else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) {
AM.ES = S->getSymbol();
//AM.SymbolFlags = S->getTargetFlags();
} else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
AM.JT = J->getIndex();
//AM.SymbolFlags = J->getTargetFlags();
} else {
AM.BlockAddr = cast<BlockAddressSDNode>(N0)->getBlockAddress();
//AM.SymbolFlags = cast<BlockAddressSDNode>(N0)->getTargetFlags();
}
return false;
}
/// MatchAddressBase - Helper for MatchAddress. Add the specified node to the
/// specified addressing mode without any further recursion.
bool MSP430DAGToDAGISel::MatchAddressBase(SDValue N, MSP430ISelAddressMode &AM) {
// Is the base register already occupied?
if (AM.BaseType != MSP430ISelAddressMode::RegBase || AM.Base.Reg.getNode()) {
// If so, we cannot select it.
return true;
}
// Default, generate it as a register.
AM.BaseType = MSP430ISelAddressMode::RegBase;
AM.Base.Reg = N;
return false;
}
bool MSP430DAGToDAGISel::MatchAddress(SDValue N, MSP430ISelAddressMode &AM) {
DEBUG(errs() << "MatchAddress: "; AM.dump());
switch (N.getOpcode()) {
default: break;
case ISD::Constant: {
uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
AM.Disp += Val;
return false;
}
case MSP430ISD::Wrapper:
if (!MatchWrapper(N, AM))
return false;
break;
case ISD::FrameIndex:
if (AM.BaseType == MSP430ISelAddressMode::RegBase
&& AM.Base.Reg.getNode() == 0) {
AM.BaseType = MSP430ISelAddressMode::FrameIndexBase;
AM.Base.FrameIndex = cast<FrameIndexSDNode>(N)->getIndex();
return false;
}
break;
case ISD::ADD: {
MSP430ISelAddressMode Backup = AM;
if (!MatchAddress(N.getNode()->getOperand(0), AM) &&
!MatchAddress(N.getNode()->getOperand(1), AM))
return false;
AM = Backup;
if (!MatchAddress(N.getNode()->getOperand(1), AM) &&
!MatchAddress(N.getNode()->getOperand(0), AM))
return false;
AM = Backup;
break;
}
case ISD::OR:
// Handle "X | C" as "X + C" iff X is known to have C bits clear.
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
MSP430ISelAddressMode Backup = AM;
uint64_t Offset = CN->getSExtValue();
// Start with the LHS as an addr mode.
if (!MatchAddress(N.getOperand(0), AM) &&
// Address could not have picked a GV address for the displacement.
AM.GV == NULL &&
// Check to see if the LHS & C is zero.
CurDAG->MaskedValueIsZero(N.getOperand(0), CN->getAPIntValue())) {
AM.Disp += Offset;
return false;
}
AM = Backup;
}
break;
}
return MatchAddressBase(N, AM);
}
/// SelectAddr - returns true if it is able pattern match an addressing mode.
/// It returns the operands which make up the maximal addressing mode it can
/// match by reference.
bool MSP430DAGToDAGISel::SelectAddr(SDValue N,
SDValue &Base, SDValue &Disp) {
MSP430ISelAddressMode AM;
if (MatchAddress(N, AM))
return false;
EVT VT = N.getValueType();
if (AM.BaseType == MSP430ISelAddressMode::RegBase) {
if (!AM.Base.Reg.getNode())
AM.Base.Reg = CurDAG->getRegister(0, VT);
}
Base = (AM.BaseType == MSP430ISelAddressMode::FrameIndexBase) ?
CurDAG->getTargetFrameIndex(AM.Base.FrameIndex,
getTargetLowering()->getPointerTy()) :
AM.Base.Reg;
if (AM.GV)
Disp = CurDAG->getTargetGlobalAddress(AM.GV, SDLoc(N),
MVT::i16, AM.Disp,
0/*AM.SymbolFlags*/);
else if (AM.CP)
Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i16,
AM.Align, AM.Disp, 0/*AM.SymbolFlags*/);
else if (AM.ES)
Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i16, 0/*AM.SymbolFlags*/);
else if (AM.JT != -1)
Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i16, 0/*AM.SymbolFlags*/);
else if (AM.BlockAddr)
Disp = CurDAG->getTargetBlockAddress(AM.BlockAddr, MVT::i32, 0,
0/*AM.SymbolFlags*/);
else
Disp = CurDAG->getTargetConstant(AM.Disp, MVT::i16);
return true;
}
bool MSP430DAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
std::vector<SDValue> &OutOps) {
SDValue Op0, Op1;
switch (ConstraintCode) {
default: return true;
case 'm': // memory
if (!SelectAddr(Op, Op0, Op1))
return true;
break;
}
OutOps.push_back(Op0);
OutOps.push_back(Op1);
return false;
}
static bool isValidIndexedLoad(const LoadSDNode *LD) {
ISD::MemIndexedMode AM = LD->getAddressingMode();
if (AM != ISD::POST_INC || LD->getExtensionType() != ISD::NON_EXTLOAD)
return false;
EVT VT = LD->getMemoryVT();
switch (VT.getSimpleVT().SimpleTy) {
case MVT::i8:
// Sanity check
if (cast<ConstantSDNode>(LD->getOffset())->getZExtValue() != 1)
return false;
break;
case MVT::i16:
// Sanity check
if (cast<ConstantSDNode>(LD->getOffset())->getZExtValue() != 2)
return false;
break;
default:
return false;
}
return true;
}
SDNode *MSP430DAGToDAGISel::SelectIndexedLoad(SDNode *N) {
LoadSDNode *LD = cast<LoadSDNode>(N);
if (!isValidIndexedLoad(LD))
return NULL;
MVT VT = LD->getMemoryVT().getSimpleVT();
unsigned Opcode = 0;
switch (VT.SimpleTy) {
case MVT::i8:
Opcode = MSP430::MOV8rm_POST;
break;
case MVT::i16:
Opcode = MSP430::MOV16rm_POST;
break;
default:
return NULL;
}
return CurDAG->getMachineNode(Opcode, SDLoc(N),
VT, MVT::i16, MVT::Other,
LD->getBasePtr(), LD->getChain());
}
SDNode *MSP430DAGToDAGISel::SelectIndexedBinOp(SDNode *Op,
SDValue N1, SDValue N2,
unsigned Opc8, unsigned Opc16) {
if (N1.getOpcode() == ISD::LOAD &&
N1.hasOneUse() &&
IsLegalToFold(N1, Op, Op, OptLevel)) {
LoadSDNode *LD = cast<LoadSDNode>(N1);
if (!isValidIndexedLoad(LD))
return NULL;
MVT VT = LD->getMemoryVT().getSimpleVT();
unsigned Opc = (VT == MVT::i16 ? Opc16 : Opc8);
MachineSDNode::mmo_iterator MemRefs0 = MF->allocateMemRefsArray(1);
MemRefs0[0] = cast<MemSDNode>(N1)->getMemOperand();
SDValue Ops0[] = { N2, LD->getBasePtr(), LD->getChain() };
SDNode *ResNode =
CurDAG->SelectNodeTo(Op, Opc,
VT, MVT::i16, MVT::Other,
Ops0, 3);
cast<MachineSDNode>(ResNode)->setMemRefs(MemRefs0, MemRefs0 + 1);
// Transfer chain.
ReplaceUses(SDValue(N1.getNode(), 2), SDValue(ResNode, 2));
// Transfer writeback.
ReplaceUses(SDValue(N1.getNode(), 1), SDValue(ResNode, 1));
return ResNode;
}
return NULL;
}
SDNode *MSP430DAGToDAGISel::Select(SDNode *Node) {
SDLoc dl(Node);
// Dump information about the Node being selected
DEBUG(errs() << "Selecting: ");
DEBUG(Node->dump(CurDAG));
DEBUG(errs() << "\n");
// If we have a custom node, we already have selected!
if (Node->isMachineOpcode()) {
DEBUG(errs() << "== ";
Node->dump(CurDAG);
errs() << "\n");
Node->setNodeId(-1);
return NULL;
}
// Few custom selection stuff.
switch (Node->getOpcode()) {
default: break;
case ISD::FrameIndex: {
assert(Node->getValueType(0) == MVT::i16);
int FI = cast<FrameIndexSDNode>(Node)->getIndex();
SDValue TFI = CurDAG->getTargetFrameIndex(FI, MVT::i16);
if (Node->hasOneUse())
return CurDAG->SelectNodeTo(Node, MSP430::ADD16ri, MVT::i16,
TFI, CurDAG->getTargetConstant(0, MVT::i16));
return CurDAG->getMachineNode(MSP430::ADD16ri, dl, MVT::i16,
TFI, CurDAG->getTargetConstant(0, MVT::i16));
}
case ISD::LOAD:
if (SDNode *ResNode = SelectIndexedLoad(Node))
return ResNode;
// Other cases are autogenerated.
break;
case ISD::ADD:
if (SDNode *ResNode =
SelectIndexedBinOp(Node,
Node->getOperand(0), Node->getOperand(1),
MSP430::ADD8rm_POST, MSP430::ADD16rm_POST))
return ResNode;
else if (SDNode *ResNode =
SelectIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
MSP430::ADD8rm_POST, MSP430::ADD16rm_POST))
return ResNode;
// Other cases are autogenerated.
break;
case ISD::SUB:
if (SDNode *ResNode =
SelectIndexedBinOp(Node,
Node->getOperand(0), Node->getOperand(1),
MSP430::SUB8rm_POST, MSP430::SUB16rm_POST))
return ResNode;
// Other cases are autogenerated.
break;
case ISD::AND:
if (SDNode *ResNode =
SelectIndexedBinOp(Node,
Node->getOperand(0), Node->getOperand(1),
MSP430::AND8rm_POST, MSP430::AND16rm_POST))
return ResNode;
else if (SDNode *ResNode =
SelectIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
MSP430::AND8rm_POST, MSP430::AND16rm_POST))
return ResNode;
// Other cases are autogenerated.
break;
case ISD::OR:
if (SDNode *ResNode =
SelectIndexedBinOp(Node,
Node->getOperand(0), Node->getOperand(1),
MSP430::OR8rm_POST, MSP430::OR16rm_POST))
return ResNode;
else if (SDNode *ResNode =
SelectIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
MSP430::OR8rm_POST, MSP430::OR16rm_POST))
return ResNode;
// Other cases are autogenerated.
break;
case ISD::XOR:
if (SDNode *ResNode =
SelectIndexedBinOp(Node,
Node->getOperand(0), Node->getOperand(1),
MSP430::XOR8rm_POST, MSP430::XOR16rm_POST))
return ResNode;
else if (SDNode *ResNode =
SelectIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
MSP430::XOR8rm_POST, MSP430::XOR16rm_POST))
return ResNode;
// Other cases are autogenerated.
break;
}
// Select the default instruction
SDNode *ResNode = SelectCode(Node);
DEBUG(errs() << "=> ");
if (ResNode == NULL || ResNode == Node)
DEBUG(Node->dump(CurDAG));
else
DEBUG(ResNode->dump(CurDAG));
DEBUG(errs() << "\n");
return ResNode;
}