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llvm-project/llvm/lib/Target/Mips/MipsISelDAGToDAG.cpp

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//===-- MipsISelDAGToDAG.cpp - A Dag to Dag Inst Selector for Mips --------===//
//
// 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 MIPS target.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mips-isel"
#include "Mips.h"
#include "MipsAnalyzeImmediate.h"
#include "MipsMachineFunction.h"
#include "MipsRegisterInfo.h"
#include "MipsSubtarget.h"
#include "MipsTargetMachine.h"
#include "llvm/GlobalValue.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Support/CFG.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// Instruction Selector Implementation
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// MipsDAGToDAGISel - MIPS specific code to select MIPS machine
// instructions for SelectionDAG operations.
//===----------------------------------------------------------------------===//
namespace {
class MipsDAGToDAGISel : public SelectionDAGISel {
/// TM - Keep a reference to MipsTargetMachine.
MipsTargetMachine &TM;
/// Subtarget - Keep a pointer to the MipsSubtarget around so that we can
/// make the right decision when generating code for different targets.
const MipsSubtarget &Subtarget;
public:
explicit MipsDAGToDAGISel(MipsTargetMachine &tm) :
SelectionDAGISel(tm),
TM(tm), Subtarget(tm.getSubtarget<MipsSubtarget>()) {}
// Pass Name
virtual const char *getPassName() const {
return "MIPS DAG->DAG Pattern Instruction Selection";
}
private:
// Include the pieces autogenerated from the target description.
#include "MipsGenDAGISel.inc"
/// getTargetMachine - Return a reference to the TargetMachine, casted
/// to the target-specific type.
const MipsTargetMachine &getTargetMachine() {
return static_cast<const MipsTargetMachine &>(TM);
}
/// getInstrInfo - Return a reference to the TargetInstrInfo, casted
/// to the target-specific type.
const MipsInstrInfo *getInstrInfo() {
return getTargetMachine().getInstrInfo();
}
SDNode *getGlobalBaseReg();
std::pair<SDNode*, SDNode*> SelectMULT(SDNode *N, unsigned Opc, DebugLoc dl,
EVT Ty, bool HasLo, bool HasHi);
SDNode *Select(SDNode *N);
// Complex Pattern.
bool SelectAddr(SDValue N, SDValue &Base, SDValue &Offset);
// getImm - Return a target constant with the specified value.
inline SDValue getImm(const SDNode *Node, unsigned Imm) {
return CurDAG->getTargetConstant(Imm, Node->getValueType(0));
}
virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
char ConstraintCode,
std::vector<SDValue> &OutOps);
};
}
/// getGlobalBaseReg - Output the instructions required to put the
/// GOT address into a register.
SDNode *MipsDAGToDAGISel::getGlobalBaseReg() {
unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
}
/// ComplexPattern used on MipsInstrInfo
/// Used on Mips Load/Store instructions
bool MipsDAGToDAGISel::
SelectAddr(SDValue Addr, SDValue &Base, SDValue &Offset) {
EVT ValTy = Addr.getValueType();
unsigned GPReg = ValTy == MVT::i32 ? Mips::GP : Mips::GP_64;
// if Address is FI, get the TargetFrameIndex.
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
Offset = CurDAG->getTargetConstant(0, ValTy);
return true;
}
// on PIC code Load GA
if (Addr.getOpcode() == MipsISD::Wrapper) {
Base = CurDAG->getRegister(GPReg, ValTy);
Offset = Addr.getOperand(0);
return true;
}
if (TM.getRelocationModel() != Reloc::PIC_) {
if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
Addr.getOpcode() == ISD::TargetGlobalAddress))
return false;
}
// Addresses of the form FI+const or FI|const
if (CurDAG->isBaseWithConstantOffset(Addr)) {
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1));
if (isInt<16>(CN->getSExtValue())) {
// If the first operand is a FI, get the TargetFI Node
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>
(Addr.getOperand(0)))
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
else
Base = Addr.getOperand(0);
Offset = CurDAG->getTargetConstant(CN->getZExtValue(), ValTy);
return true;
}
}
// Operand is a result from an ADD.
if (Addr.getOpcode() == ISD::ADD) {
// When loading from constant pools, load the lower address part in
// the instruction itself. Example, instead of:
// lui $2, %hi($CPI1_0)
// addiu $2, $2, %lo($CPI1_0)
// lwc1 $f0, 0($2)
// Generate:
// lui $2, %hi($CPI1_0)
// lwc1 $f0, %lo($CPI1_0)($2)
if (Addr.getOperand(1).getOpcode() == MipsISD::Lo) {
SDValue LoVal = Addr.getOperand(1);
if (isa<ConstantPoolSDNode>(LoVal.getOperand(0)) ||
isa<GlobalAddressSDNode>(LoVal.getOperand(0))) {
Base = Addr.getOperand(0);
Offset = LoVal.getOperand(0);
return true;
}
}
}
Base = Addr;
Offset = CurDAG->getTargetConstant(0, ValTy);
return true;
}
/// Select multiply instructions.
std::pair<SDNode*, SDNode*>
MipsDAGToDAGISel::SelectMULT(SDNode *N, unsigned Opc, DebugLoc dl, EVT Ty,
bool HasLo, bool HasHi) {
SDNode *Lo = 0, *Hi = 0;
SDNode *Mul = CurDAG->getMachineNode(Opc, dl, MVT::Glue, N->getOperand(0),
N->getOperand(1));
SDValue InFlag = SDValue(Mul, 0);
if (HasLo) {
Lo = CurDAG->getMachineNode(Ty == MVT::i32 ? Mips::MFLO : Mips::MFLO64, dl,
Ty, MVT::Glue, InFlag);
InFlag = SDValue(Lo, 1);
}
if (HasHi)
Hi = CurDAG->getMachineNode(Ty == MVT::i32 ? Mips::MFHI : Mips::MFHI64, dl,
Ty, InFlag);
return std::make_pair(Lo, Hi);
}
/// Select instructions not customized! Used for
/// expanded, promoted and normal instructions
SDNode* MipsDAGToDAGISel::Select(SDNode *Node) {
unsigned Opcode = Node->getOpcode();
DebugLoc dl = Node->getDebugLoc();
// Dump information about the Node being selected
DEBUG(errs() << "Selecting: "; Node->dump(CurDAG); errs() << "\n");
// If we have a custom node, we already have selected!
if (Node->isMachineOpcode()) {
DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
return NULL;
}
///
// Instruction Selection not handled by the auto-generated
// tablegen selection should be handled here.
///
EVT NodeTy = Node->getValueType(0);
unsigned MultOpc;
switch(Opcode) {
default: break;
case ISD::SUBE:
case ISD::ADDE: {
SDValue InFlag = Node->getOperand(2), CmpLHS;
unsigned Opc = InFlag.getOpcode(); (void)Opc;
assert(((Opc == ISD::ADDC || Opc == ISD::ADDE) ||
(Opc == ISD::SUBC || Opc == ISD::SUBE)) &&
"(ADD|SUB)E flag operand must come from (ADD|SUB)C/E insn");
unsigned MOp;
if (Opcode == ISD::ADDE) {
CmpLHS = InFlag.getValue(0);
MOp = Mips::ADDu;
} else {
CmpLHS = InFlag.getOperand(0);
MOp = Mips::SUBu;
}
SDValue Ops[] = { CmpLHS, InFlag.getOperand(1) };
SDValue LHS = Node->getOperand(0);
SDValue RHS = Node->getOperand(1);
EVT VT = LHS.getValueType();
SDNode *Carry = CurDAG->getMachineNode(Mips::SLTu, dl, VT, Ops, 2);
SDNode *AddCarry = CurDAG->getMachineNode(Mips::ADDu, dl, VT,
SDValue(Carry,0), RHS);
return CurDAG->SelectNodeTo(Node, MOp, VT, MVT::Glue,
LHS, SDValue(AddCarry,0));
}
/// Mul with two results
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI: {
if (NodeTy == MVT::i32)
MultOpc = (Opcode == ISD::UMUL_LOHI ? Mips::MULTu : Mips::MULT);
else
MultOpc = (Opcode == ISD::UMUL_LOHI ? Mips::DMULTu : Mips::DMULT);
std::pair<SDNode*, SDNode*> LoHi = SelectMULT(Node, MultOpc, dl, NodeTy,
true, true);
if (!SDValue(Node, 0).use_empty())
ReplaceUses(SDValue(Node, 0), SDValue(LoHi.first, 0));
if (!SDValue(Node, 1).use_empty())
ReplaceUses(SDValue(Node, 1), SDValue(LoHi.second, 0));
return NULL;
}
/// Special Muls
case ISD::MUL: {
// Mips32 has a 32-bit three operand mul instruction.
if (Subtarget.hasMips32() && NodeTy == MVT::i32)
break;
return SelectMULT(Node, NodeTy == MVT::i32 ? Mips::MULT : Mips::DMULT,
dl, NodeTy, true, false).first;
}
case ISD::MULHS:
case ISD::MULHU: {
if (NodeTy == MVT::i32)
MultOpc = (Opcode == ISD::MULHU ? Mips::MULTu : Mips::MULT);
else
MultOpc = (Opcode == ISD::MULHU ? Mips::DMULTu : Mips::DMULT);
return SelectMULT(Node, MultOpc, dl, NodeTy, false, true).second;
}
// Get target GOT address.
case ISD::GLOBAL_OFFSET_TABLE:
return getGlobalBaseReg();
case ISD::ConstantFP: {
ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(Node);
if (Node->getValueType(0) == MVT::f64 && CN->isExactlyValue(+0.0)) {
if (Subtarget.hasMips64()) {
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
Mips::ZERO_64, MVT::i64);
return CurDAG->getMachineNode(Mips::DMTC1, dl, MVT::f64, Zero);
}
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
Mips::ZERO, MVT::i32);
return CurDAG->getMachineNode(Mips::BuildPairF64, dl, MVT::f64, Zero,
Zero);
}
break;
}
case ISD::Constant: {
const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Node);
unsigned Size = CN->getValueSizeInBits(0);
if (Size == 32)
break;
MipsAnalyzeImmediate AnalyzeImm;
int64_t Imm = CN->getSExtValue();
const MipsAnalyzeImmediate::InstSeq &Seq =
AnalyzeImm.Analyze(Imm, Size, false);
MipsAnalyzeImmediate::InstSeq::const_iterator Inst = Seq.begin();
DebugLoc DL = CN->getDebugLoc();
SDNode *RegOpnd;
SDValue ImmOpnd = CurDAG->getTargetConstant(SignExtend64<16>(Inst->ImmOpnd),
MVT::i64);
// The first instruction can be a LUi which is different from other
// instructions (ADDiu, ORI and SLL) in that it does not have a register
// operand.
if (Inst->Opc == Mips::LUi64)
RegOpnd = CurDAG->getMachineNode(Inst->Opc, DL, MVT::i64, ImmOpnd);
else
RegOpnd =
CurDAG->getMachineNode(Inst->Opc, DL, MVT::i64,
CurDAG->getRegister(Mips::ZERO_64, MVT::i64),
ImmOpnd);
// The remaining instructions in the sequence are handled here.
for (++Inst; Inst != Seq.end(); ++Inst) {
ImmOpnd = CurDAG->getTargetConstant(SignExtend64<16>(Inst->ImmOpnd),
MVT::i64);
RegOpnd = CurDAG->getMachineNode(Inst->Opc, DL, MVT::i64,
SDValue(RegOpnd, 0), ImmOpnd);
}
return RegOpnd;
}
case MipsISD::ThreadPointer: {
EVT PtrVT = TLI.getPointerTy();
unsigned RdhwrOpc, SrcReg, DestReg;
if (PtrVT == MVT::i32) {
RdhwrOpc = Mips::RDHWR;
SrcReg = Mips::HWR29;
DestReg = Mips::V1;
} else {
RdhwrOpc = Mips::RDHWR64;
SrcReg = Mips::HWR29_64;
DestReg = Mips::V1_64;
}
SDNode *Rdhwr =
CurDAG->getMachineNode(RdhwrOpc, Node->getDebugLoc(),
Node->getValueType(0),
CurDAG->getRegister(SrcReg, PtrVT));
SDValue Chain = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, DestReg,
SDValue(Rdhwr, 0));
SDValue ResNode = CurDAG->getCopyFromReg(Chain, dl, DestReg, PtrVT);
ReplaceUses(SDValue(Node, 0), ResNode);
return ResNode.getNode();
}
}
// 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;
}
bool MipsDAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
std::vector<SDValue> &OutOps) {
assert(ConstraintCode == 'm' && "unexpected asm memory constraint");
OutOps.push_back(Op);
return false;
}
/// createMipsISelDag - This pass converts a legalized DAG into a
/// MIPS-specific DAG, ready for instruction scheduling.
FunctionPass *llvm::createMipsISelDag(MipsTargetMachine &TM) {
return new MipsDAGToDAGISel(TM);
}
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