llvm-6502/lib/Target/Blackfin/BlackfinISelDAGToDAG.cpp

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//===- BlackfinISelDAGToDAG.cpp - A dag to dag inst selector for Blackfin -===//
//
// 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 Blackfin target.
//
//===----------------------------------------------------------------------===//
#include "Blackfin.h"
#include "BlackfinISelLowering.h"
#include "BlackfinTargetMachine.h"
#include "BlackfinRegisterInfo.h"
#include "llvm/Intrinsics.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// Instruction Selector Implementation
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
/// BlackfinDAGToDAGISel - Blackfin specific code to select blackfin machine
/// instructions for SelectionDAG operations.
namespace {
class BlackfinDAGToDAGISel : public SelectionDAGISel {
/// Subtarget - Keep a pointer to the Blackfin Subtarget around so that we
/// can make the right decision when generating code for different targets.
//const BlackfinSubtarget &Subtarget;
public:
BlackfinDAGToDAGISel(BlackfinTargetMachine &TM, CodeGenOpt::Level OptLevel)
: SelectionDAGISel(TM, OptLevel) {}
virtual void InstructionSelect();
virtual const char *getPassName() const {
return "Blackfin DAG->DAG Pattern Instruction Selection";
}
// Include the pieces autogenerated from the target description.
#include "BlackfinGenDAGISel.inc"
private:
SDNode *Select(SDValue Op);
bool SelectADDRspii(SDValue Op, SDValue Addr,
SDValue &Base, SDValue &Offset);
// Walk the DAG after instruction selection, fixing register class issues.
void FixRegisterClasses(SelectionDAG &DAG);
const BlackfinInstrInfo &getInstrInfo() {
return *static_cast<const BlackfinTargetMachine&>(TM).getInstrInfo();
}
const BlackfinRegisterInfo *getRegisterInfo() {
return static_cast<const BlackfinTargetMachine&>(TM).getRegisterInfo();
}
};
} // end anonymous namespace
FunctionPass *llvm::createBlackfinISelDag(BlackfinTargetMachine &TM,
CodeGenOpt::Level OptLevel) {
return new BlackfinDAGToDAGISel(TM, OptLevel);
}
/// InstructionSelect - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
void BlackfinDAGToDAGISel::InstructionSelect() {
// Select target instructions for the DAG.
SelectRoot(*CurDAG);
DEBUG(errs() << "Selected selection DAG before regclass fixup:\n");
DEBUG(CurDAG->dump());
FixRegisterClasses(*CurDAG);
}
SDNode *BlackfinDAGToDAGISel::Select(SDValue Op) {
SDNode *N = Op.getNode();
if (N->isMachineOpcode())
return NULL; // Already selected.
switch (N->getOpcode()) {
default: break;
case ISD::FrameIndex: {
// Selects to ADDpp FI, 0 which in turn will become ADDimm7 SP, imm or ADDpp
// SP, Px
int FI = cast<FrameIndexSDNode>(N)->getIndex();
SDValue TFI = CurDAG->getTargetFrameIndex(FI, MVT::i32);
return CurDAG->SelectNodeTo(N, BF::ADDpp, MVT::i32, TFI,
CurDAG->getTargetConstant(0, MVT::i32));
}
}
return SelectCode(Op);
}
bool BlackfinDAGToDAGISel::SelectADDRspii(SDValue Op,
SDValue Addr,
SDValue &Base,
SDValue &Offset) {
FrameIndexSDNode *FIN = 0;
if ((FIN = dyn_cast<FrameIndexSDNode>(Addr))) {
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
Offset = CurDAG->getTargetConstant(0, MVT::i32);
return true;
}
if (Addr.getOpcode() == ISD::ADD) {
ConstantSDNode *CN = 0;
if ((FIN = dyn_cast<FrameIndexSDNode>(Addr.getOperand(0))) &&
(CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) &&
(CN->getSExtValue() % 4 == 0 && CN->getSExtValue() >= 0)) {
// Constant positive word offset from frame index
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
Offset = CurDAG->getTargetConstant(CN->getSExtValue(), MVT::i32);
return true;
}
}
return false;
}
static inline bool isCC(const TargetRegisterClass *RC) {
return RC == &BF::AnyCCRegClass || BF::AnyCCRegClass.hasSubClass(RC);
}
static inline bool isDCC(const TargetRegisterClass *RC) {
return RC == &BF::DRegClass || BF::DRegClass.hasSubClass(RC) || isCC(RC);
}
static void UpdateNodeOperand(SelectionDAG &DAG,
SDNode *N,
unsigned Num,
SDValue Val) {
SmallVector<SDValue, 8> ops(N->op_begin(), N->op_end());
ops[Num] = Val;
SDValue New = DAG.UpdateNodeOperands(SDValue(N, 0), ops.data(), ops.size());
DAG.ReplaceAllUsesWith(N, New.getNode());
}
// After instruction selection, insert COPY_TO_REGCLASS nodes to help in
// choosing the proper register classes.
void BlackfinDAGToDAGISel::FixRegisterClasses(SelectionDAG &DAG) {
const BlackfinInstrInfo &TII = getInstrInfo();
const BlackfinRegisterInfo *TRI = getRegisterInfo();
DAG.AssignTopologicalOrder();
HandleSDNode Dummy(DAG.getRoot());
for (SelectionDAG::allnodes_iterator NI = DAG.allnodes_begin();
NI != DAG.allnodes_end(); ++NI) {
if (NI->use_empty() || !NI->isMachineOpcode())
continue;
const TargetInstrDesc &DefTID = TII.get(NI->getMachineOpcode());
for (SDNode::use_iterator UI = NI->use_begin(); !UI.atEnd(); ++UI) {
if (!UI->isMachineOpcode())
continue;
if (UI.getUse().getResNo() >= DefTID.getNumDefs())
continue;
const TargetRegisterClass *DefRC =
DefTID.OpInfo[UI.getUse().getResNo()].getRegClass(TRI);
const TargetInstrDesc &UseTID = TII.get(UI->getMachineOpcode());
if (UseTID.getNumDefs()+UI.getOperandNo() >= UseTID.getNumOperands())
continue;
const TargetRegisterClass *UseRC =
UseTID.OpInfo[UseTID.getNumDefs()+UI.getOperandNo()].getRegClass(TRI);
if (!DefRC || !UseRC)
continue;
// We cannot copy CC <-> !(CC/D)
if ((isCC(DefRC) && !isDCC(UseRC)) || (isCC(UseRC) && !isDCC(DefRC))) {
SDNode *Copy =
DAG.getMachineNode(TargetInstrInfo::COPY_TO_REGCLASS,
NI->getDebugLoc(),
MVT::i32,
UI.getUse().get(),
DAG.getTargetConstant(BF::DRegClassID, MVT::i32));
UpdateNodeOperand(DAG, *UI, UI.getOperandNo(), SDValue(Copy, 0));
}
}
}
DAG.setRoot(Dummy.getValue());
}