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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 "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();
SDNode *Select(SDNode *N);
// Complex Pattern.
bool SelectAddr(SDValue N, SDValue &Base, SDValue &Offset);
SDNode *SelectLoadFp64(SDNode *N);
SDNode *SelectStoreFp64(SDNode *N);
// getI32Imm - Return a target constant with the specified
// value, of type i32.
inline SDValue getI32Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i32);
}
};
}
/// 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 &Offset, SDValue &Base) {
// if Address is FI, get the TargetFrameIndex.
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
Offset = CurDAG->getTargetConstant(0, MVT::i32);
return true;
}
// on PIC code Load GA
if (TM.getRelocationModel() == Reloc::PIC_) {
if ((Addr.getOpcode() == ISD::TargetGlobalAddress) ||
(Addr.getOpcode() == ISD::TargetConstantPool) ||
(Addr.getOpcode() == ISD::TargetJumpTable)){
Base = CurDAG->getRegister(Mips::GP, MVT::i32);
Offset = Addr;
return true;
}
} else {
if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
Addr.getOpcode() == ISD::TargetGlobalAddress))
return false;
}
// Operand is a result from an ADD.
if (Addr.getOpcode() == ISD::ADD) {
if (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(), MVT::i32);
} else {
Base = Addr.getOperand(0);
}
Offset = CurDAG->getTargetConstant(CN->getZExtValue(), MVT::i32);
return true;
}
}
// 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(0).getOpcode() == MipsISD::Hi ||
Addr.getOperand(0).getOpcode() == ISD::LOAD) &&
Addr.getOperand(1).getOpcode() == MipsISD::Lo) {
SDValue LoVal = Addr.getOperand(1);
if (dyn_cast<ConstantPoolSDNode>(LoVal.getOperand(0))) {
Base = Addr.getOperand(0);
Offset = LoVal.getOperand(0);
return true;
}
}
}
Base = Addr;
Offset = CurDAG->getTargetConstant(0, MVT::i32);
return true;
}
SDNode *MipsDAGToDAGISel::SelectLoadFp64(SDNode *N) {
MVT::SimpleValueType NVT =
N->getValueType(0).getSimpleVT().SimpleTy;
if (!Subtarget.isMips1() || NVT != MVT::f64)
return NULL;
LoadSDNode *LN = cast<LoadSDNode>(N);
if (LN->getExtensionType() != ISD::NON_EXTLOAD ||
LN->getAddressingMode() != ISD::UNINDEXED)
return NULL;
SDValue Chain = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue Offset0, Offset1, Base;
if (!SelectAddr(N1, Offset0, Base) ||
N1.getValueType() != MVT::i32)
return NULL;
MachineSDNode::mmo_iterator MemRefs0 = MF->allocateMemRefsArray(1);
MemRefs0[0] = cast<MemSDNode>(N)->getMemOperand();
DebugLoc dl = N->getDebugLoc();
// The second load should start after for 4 bytes.
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Offset0))
Offset1 = CurDAG->getTargetConstant(C->getSExtValue()+4, MVT::i32);
else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Offset0))
Offset1 = CurDAG->getTargetConstantPool(CP->getConstVal(),
MVT::i32,
CP->getAlignment(),
CP->getOffset()+4,
CP->getTargetFlags());
else
return NULL;
// Choose the offsets depending on the endianess
if (TM.getTargetData()->isBigEndian())
std::swap(Offset0, Offset1);
// Instead of:
// ldc $f0, X($3)
// Generate:
// lwc $f0, X($3)
// lwc $f1, X+4($3)
SDNode *LD0 = CurDAG->getMachineNode(Mips::LWC1, dl, MVT::f32,
MVT::Other, Offset0, Base, Chain);
SDValue Undef = SDValue(CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF,
dl, NVT), 0);
SDValue I0 = CurDAG->getTargetInsertSubreg(Mips::sub_fpeven, dl,
MVT::f64, Undef, SDValue(LD0, 0));
SDNode *LD1 = CurDAG->getMachineNode(Mips::LWC1, dl, MVT::f32,
MVT::Other, Offset1, Base, SDValue(LD0, 1));
SDValue I1 = CurDAG->getTargetInsertSubreg(Mips::sub_fpodd, dl,
MVT::f64, I0, SDValue(LD1, 0));
ReplaceUses(SDValue(N, 0), I1);
ReplaceUses(SDValue(N, 1), Chain);
cast<MachineSDNode>(LD0)->setMemRefs(MemRefs0, MemRefs0 + 1);
cast<MachineSDNode>(LD1)->setMemRefs(MemRefs0, MemRefs0 + 1);
return I1.getNode();
}
SDNode *MipsDAGToDAGISel::SelectStoreFp64(SDNode *N) {
if (!Subtarget.isMips1() ||
N->getOperand(1).getValueType() != MVT::f64)
return NULL;
SDValue Chain = N->getOperand(0);
StoreSDNode *SN = cast<StoreSDNode>(N);
if (SN->isTruncatingStore() || SN->getAddressingMode() != ISD::UNINDEXED)
return NULL;
SDValue N1 = N->getOperand(1);
SDValue N2 = N->getOperand(2);
SDValue Offset0, Offset1, Base;
if (!SelectAddr(N2, Offset0, Base) ||
N1.getValueType() != MVT::f64 ||
N2.getValueType() != MVT::i32)
return NULL;
MachineSDNode::mmo_iterator MemRefs0 = MF->allocateMemRefsArray(1);
MemRefs0[0] = cast<MemSDNode>(N)->getMemOperand();
DebugLoc dl = N->getDebugLoc();
// Get the even and odd part from the f64 register
SDValue FPOdd = CurDAG->getTargetExtractSubreg(Mips::sub_fpodd,
dl, MVT::f32, N1);
SDValue FPEven = CurDAG->getTargetExtractSubreg(Mips::sub_fpeven,
dl, MVT::f32, N1);
// The second store should start after for 4 bytes.
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Offset0))
Offset1 = CurDAG->getTargetConstant(C->getSExtValue()+4, MVT::i32);
else
return NULL;
// Choose the offsets depending on the endianess
if (TM.getTargetData()->isBigEndian())
std::swap(Offset0, Offset1);
// Instead of:
// sdc $f0, X($3)
// Generate:
// swc $f0, X($3)
// swc $f1, X+4($3)
SDValue Ops0[] = { FPEven, Offset0, Base, Chain };
Chain = SDValue(CurDAG->getMachineNode(Mips::SWC1, dl,
MVT::Other, Ops0, 4), 0);
cast<MachineSDNode>(Chain.getNode())->setMemRefs(MemRefs0, MemRefs0 + 1);
SDValue Ops1[] = { FPOdd, Offset1, Base, Chain };
Chain = SDValue(CurDAG->getMachineNode(Mips::SWC1, dl,
MVT::Other, Ops1, 4), 0);
cast<MachineSDNode>(Chain.getNode())->setMemRefs(MemRefs0, MemRefs0 + 1);
ReplaceUses(SDValue(N, 0), Chain);
return Chain.getNode();
}
/// 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.
///
switch(Opcode) {
default: break;
case ISD::SUBE:
case ISD::ADDE: {
SDValue InFlag = Node->getOperand(2), CmpLHS;
unsigned Opc = InFlag.getOpcode(); Opc=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::Flag,
LHS, SDValue(AddCarry,0));
}
/// Mul/Div with two results
case ISD::SDIVREM:
case ISD::UDIVREM:
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI: {
SDValue Op1 = Node->getOperand(0);
SDValue Op2 = Node->getOperand(1);
unsigned Op;
if (Opcode == ISD::UMUL_LOHI || Opcode == ISD::SMUL_LOHI)
Op = (Opcode == ISD::UMUL_LOHI ? Mips::MULTu : Mips::MULT);
else
Op = (Opcode == ISD::UDIVREM ? Mips::DIVu : Mips::DIV);
SDNode *MulDiv = CurDAG->getMachineNode(Op, dl, MVT::Flag, Op1, Op2);
SDValue InFlag = SDValue(MulDiv, 0);
SDNode *Lo = CurDAG->getMachineNode(Mips::MFLO, dl, MVT::i32,
MVT::Flag, InFlag);
InFlag = SDValue(Lo,1);
SDNode *Hi = CurDAG->getMachineNode(Mips::MFHI, dl, MVT::i32, InFlag);
if (!SDValue(Node, 0).use_empty())
ReplaceUses(SDValue(Node, 0), SDValue(Lo,0));
if (!SDValue(Node, 1).use_empty())
ReplaceUses(SDValue(Node, 1), SDValue(Hi,0));
return NULL;
}
/// Special Muls
case ISD::MUL:
case ISD::MULHS:
case ISD::MULHU: {
SDValue MulOp1 = Node->getOperand(0);
SDValue MulOp2 = Node->getOperand(1);
unsigned MulOp = (Opcode == ISD::MULHU ? Mips::MULTu : Mips::MULT);
SDNode *MulNode = CurDAG->getMachineNode(MulOp, dl,
MVT::Flag, MulOp1, MulOp2);
SDValue InFlag = SDValue(MulNode, 0);
if (Opcode == ISD::MUL)
return CurDAG->getMachineNode(Mips::MFLO, dl, MVT::i32, InFlag);
else
return CurDAG->getMachineNode(Mips::MFHI, dl, MVT::i32, InFlag);
}
/// Div/Rem operations
case ISD::SREM:
case ISD::UREM:
case ISD::SDIV:
case ISD::UDIV: {
SDValue Op1 = Node->getOperand(0);
SDValue Op2 = Node->getOperand(1);
unsigned Op, MOp;
if (Opcode == ISD::SDIV || Opcode == ISD::UDIV) {
Op = (Opcode == ISD::SDIV ? Mips::DIV : Mips::DIVu);
MOp = Mips::MFLO;
} else {
Op = (Opcode == ISD::SREM ? Mips::DIV : Mips::DIVu);
MOp = Mips::MFHI;
}
SDNode *Node = CurDAG->getMachineNode(Op, dl, MVT::Flag, Op1, Op2);
SDValue InFlag = SDValue(Node, 0);
return CurDAG->getMachineNode(MOp, dl, MVT::i32, InFlag);
}
// 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)) {
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
Mips::ZERO, MVT::i32);
SDValue Undef = SDValue(
CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF, dl, MVT::f64), 0);
SDNode *MTC = CurDAG->getMachineNode(Mips::MTC1, dl, MVT::f32, Zero);
SDValue I0 = CurDAG->getTargetInsertSubreg(Mips::sub_fpeven, dl,
MVT::f64, Undef, SDValue(MTC, 0));
SDValue I1 = CurDAG->getTargetInsertSubreg(Mips::sub_fpodd, dl,
MVT::f64, I0, SDValue(MTC, 0));
ReplaceUses(SDValue(Node, 0), I1);
return I1.getNode();
}
break;
}
case ISD::LOAD:
if (SDNode *ResNode = SelectLoadFp64(Node))
return ResNode;
// Other cases are autogenerated.
break;
case ISD::STORE:
if (SDNode *ResNode = SelectStoreFp64(Node))
return ResNode;
// Other cases are autogenerated.
break;
/// Handle direct and indirect calls when using PIC. On PIC, when
/// GOT is smaller than about 64k (small code) the GA target is
/// loaded with only one instruction. Otherwise GA's target must
/// be loaded with 3 instructions.
case MipsISD::JmpLink: {
if (TM.getRelocationModel() == Reloc::PIC_) {
unsigned LastOpNum = Node->getNumOperands()-1;
SDValue Chain = Node->getOperand(0);
SDValue Callee = Node->getOperand(1);
SDValue InFlag;
// Skip the incomming flag if present
if (Node->getOperand(LastOpNum).getValueType() == MVT::Flag)
LastOpNum--;
if ( (isa<GlobalAddressSDNode>(Callee)) ||
(isa<ExternalSymbolSDNode>(Callee)) )
{
/// Direct call for global addresses and external symbols
SDValue GPReg = CurDAG->getRegister(Mips::GP, MVT::i32);
// Use load to get GOT target
SDValue Ops[] = { Callee, GPReg, Chain };
SDValue Load = SDValue(CurDAG->getMachineNode(Mips::LW, dl, MVT::i32,
MVT::Other, Ops, 3), 0);
Chain = Load.getValue(1);
// Call target must be on T9
Chain = CurDAG->getCopyToReg(Chain, dl, Mips::T9, Load, InFlag);
} else
/// Indirect call
Chain = CurDAG->getCopyToReg(Chain, dl, Mips::T9, Callee, InFlag);
// Map the JmpLink operands to JALR
SDVTList NodeTys = CurDAG->getVTList(MVT::Other, MVT::Flag);
SmallVector<SDValue, 8> Ops;
Ops.push_back(CurDAG->getRegister(Mips::T9, MVT::i32));
for (unsigned i = 2, e = LastOpNum+1; i != e; ++i)
Ops.push_back(Node->getOperand(i));
Ops.push_back(Chain);
Ops.push_back(Chain.getValue(1));
// Emit Jump and Link Register
SDNode *ResNode = CurDAG->getMachineNode(Mips::JALR, dl, NodeTys,
&Ops[0], Ops.size());
// Replace Chain and InFlag
ReplaceUses(SDValue(Node, 0), SDValue(ResNode, 0));
ReplaceUses(SDValue(Node, 1), SDValue(ResNode, 1));
return ResNode;
}
}
}
// 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;
}
/// 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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