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

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//===-- MipsSEISelDAGToDAG.cpp - A Dag to Dag Inst Selector for MipsSE ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Subclass of MipsDAGToDAGISel specialized for mips32/64.
//
//===----------------------------------------------------------------------===//
#include "MipsSEISelDAGToDAG.h"
#include "MCTargetDesc/MipsBaseInfo.h"
#include "Mips.h"
#include "MipsAnalyzeImmediate.h"
#include "MipsMachineFunction.h"
#include "MipsRegisterInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
#define DEBUG_TYPE "mips-isel"
bool MipsSEDAGToDAGISel::runOnMachineFunction(MachineFunction &MF) {
Subtarget = &static_cast<const MipsSubtarget &>(MF.getSubtarget());
if (Subtarget->inMips16Mode())
return false;
return MipsDAGToDAGISel::runOnMachineFunction(MF);
}
void MipsSEDAGToDAGISel::addDSPCtrlRegOperands(bool IsDef, MachineInstr &MI,
MachineFunction &MF) {
MachineInstrBuilder MIB(MF, &MI);
unsigned Mask = MI.getOperand(1).getImm();
unsigned Flag = IsDef ? RegState::ImplicitDefine : RegState::Implicit;
if (Mask & 1)
MIB.addReg(Mips::DSPPos, Flag);
if (Mask & 2)
MIB.addReg(Mips::DSPSCount, Flag);
if (Mask & 4)
MIB.addReg(Mips::DSPCarry, Flag);
if (Mask & 8)
MIB.addReg(Mips::DSPOutFlag, Flag);
if (Mask & 16)
MIB.addReg(Mips::DSPCCond, Flag);
if (Mask & 32)
MIB.addReg(Mips::DSPEFI, Flag);
}
unsigned MipsSEDAGToDAGISel::getMSACtrlReg(const SDValue RegIdx) const {
switch (cast<ConstantSDNode>(RegIdx)->getZExtValue()) {
default:
llvm_unreachable("Could not map int to register");
case 0: return Mips::MSAIR;
case 1: return Mips::MSACSR;
case 2: return Mips::MSAAccess;
case 3: return Mips::MSASave;
case 4: return Mips::MSAModify;
case 5: return Mips::MSARequest;
case 6: return Mips::MSAMap;
case 7: return Mips::MSAUnmap;
}
}
bool MipsSEDAGToDAGISel::replaceUsesWithZeroReg(MachineRegisterInfo *MRI,
const MachineInstr& MI) {
unsigned DstReg = 0, ZeroReg = 0;
// Check if MI is "addiu $dst, $zero, 0" or "daddiu $dst, $zero, 0".
if ((MI.getOpcode() == Mips::ADDiu) &&
(MI.getOperand(1).getReg() == Mips::ZERO) &&
(MI.getOperand(2).getImm() == 0)) {
DstReg = MI.getOperand(0).getReg();
ZeroReg = Mips::ZERO;
} else if ((MI.getOpcode() == Mips::DADDiu) &&
(MI.getOperand(1).getReg() == Mips::ZERO_64) &&
(MI.getOperand(2).getImm() == 0)) {
DstReg = MI.getOperand(0).getReg();
ZeroReg = Mips::ZERO_64;
}
if (!DstReg)
return false;
// Replace uses with ZeroReg.
for (MachineRegisterInfo::use_iterator U = MRI->use_begin(DstReg),
E = MRI->use_end(); U != E;) {
MachineOperand &MO = *U;
unsigned OpNo = U.getOperandNo();
MachineInstr *MI = MO.getParent();
++U;
// Do not replace if it is a phi's operand or is tied to def operand.
if (MI->isPHI() || MI->isRegTiedToDefOperand(OpNo) || MI->isPseudo())
continue;
// Also, we have to check that the register class of the operand
// contains the zero register.
if (!MRI->getRegClass(MO.getReg())->contains(ZeroReg))
continue;
MO.setReg(ZeroReg);
}
return true;
}
void MipsSEDAGToDAGISel::initGlobalBaseReg(MachineFunction &MF) {
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
if (!MipsFI->globalBaseRegSet())
return;
MachineBasicBlock &MBB = MF.front();
MachineBasicBlock::iterator I = MBB.begin();
MachineRegisterInfo &RegInfo = MF.getRegInfo();
const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
DebugLoc DL;
unsigned V0, V1, GlobalBaseReg = MipsFI->getGlobalBaseReg();
const TargetRegisterClass *RC;
const MipsABIInfo &ABI = static_cast<const MipsTargetMachine &>(TM).getABI();
RC = (ABI.IsN64()) ? &Mips::GPR64RegClass : &Mips::GPR32RegClass;
V0 = RegInfo.createVirtualRegister(RC);
V1 = RegInfo.createVirtualRegister(RC);
if (ABI.IsN64()) {
MF.getRegInfo().addLiveIn(Mips::T9_64);
MBB.addLiveIn(Mips::T9_64);
// lui $v0, %hi(%neg(%gp_rel(fname)))
// daddu $v1, $v0, $t9
// daddiu $globalbasereg, $v1, %lo(%neg(%gp_rel(fname)))
const GlobalValue *FName = MF.getFunction();
BuildMI(MBB, I, DL, TII.get(Mips::LUi64), V0)
.addGlobalAddress(FName, 0, MipsII::MO_GPOFF_HI);
BuildMI(MBB, I, DL, TII.get(Mips::DADDu), V1).addReg(V0)
.addReg(Mips::T9_64);
BuildMI(MBB, I, DL, TII.get(Mips::DADDiu), GlobalBaseReg).addReg(V1)
.addGlobalAddress(FName, 0, MipsII::MO_GPOFF_LO);
return;
}
if (MF.getTarget().getRelocationModel() == Reloc::Static) {
// Set global register to __gnu_local_gp.
//
// lui $v0, %hi(__gnu_local_gp)
// addiu $globalbasereg, $v0, %lo(__gnu_local_gp)
BuildMI(MBB, I, DL, TII.get(Mips::LUi), V0)
.addExternalSymbol("__gnu_local_gp", MipsII::MO_ABS_HI);
BuildMI(MBB, I, DL, TII.get(Mips::ADDiu), GlobalBaseReg).addReg(V0)
.addExternalSymbol("__gnu_local_gp", MipsII::MO_ABS_LO);
return;
}
MF.getRegInfo().addLiveIn(Mips::T9);
MBB.addLiveIn(Mips::T9);
if (ABI.IsN32()) {
// lui $v0, %hi(%neg(%gp_rel(fname)))
// addu $v1, $v0, $t9
// addiu $globalbasereg, $v1, %lo(%neg(%gp_rel(fname)))
const GlobalValue *FName = MF.getFunction();
BuildMI(MBB, I, DL, TII.get(Mips::LUi), V0)
.addGlobalAddress(FName, 0, MipsII::MO_GPOFF_HI);
BuildMI(MBB, I, DL, TII.get(Mips::ADDu), V1).addReg(V0).addReg(Mips::T9);
BuildMI(MBB, I, DL, TII.get(Mips::ADDiu), GlobalBaseReg).addReg(V1)
.addGlobalAddress(FName, 0, MipsII::MO_GPOFF_LO);
return;
}
assert(ABI.IsO32());
// For O32 ABI, the following instruction sequence is emitted to initialize
// the global base register:
//
// 0. lui $2, %hi(_gp_disp)
// 1. addiu $2, $2, %lo(_gp_disp)
// 2. addu $globalbasereg, $2, $t9
//
// We emit only the last instruction here.
//
// GNU linker requires that the first two instructions appear at the beginning
// of a function and no instructions be inserted before or between them.
// The two instructions are emitted during lowering to MC layer in order to
// avoid any reordering.
//
// Register $2 (Mips::V0) is added to the list of live-in registers to ensure
// the value instruction 1 (addiu) defines is valid when instruction 2 (addu)
// reads it.
MF.getRegInfo().addLiveIn(Mips::V0);
MBB.addLiveIn(Mips::V0);
BuildMI(MBB, I, DL, TII.get(Mips::ADDu), GlobalBaseReg)
.addReg(Mips::V0).addReg(Mips::T9);
}
void MipsSEDAGToDAGISel::processFunctionAfterISel(MachineFunction &MF) {
initGlobalBaseReg(MF);
MachineRegisterInfo *MRI = &MF.getRegInfo();
for (MachineFunction::iterator MFI = MF.begin(), MFE = MF.end(); MFI != MFE;
++MFI)
for (MachineBasicBlock::iterator I = MFI->begin(); I != MFI->end(); ++I) {
if (I->getOpcode() == Mips::RDDSP)
addDSPCtrlRegOperands(false, *I, MF);
else if (I->getOpcode() == Mips::WRDSP)
addDSPCtrlRegOperands(true, *I, MF);
else
replaceUsesWithZeroReg(MRI, *I);
}
}
SDNode *MipsSEDAGToDAGISel::selectAddESubE(unsigned MOp, SDValue InFlag,
SDValue CmpLHS, SDLoc DL,
SDNode *Node) const {
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 SLTuOp = Mips::SLTu, ADDuOp = Mips::ADDu;
if (Subtarget->isGP64bit()) {
SLTuOp = Mips::SLTu64;
ADDuOp = Mips::DADDu;
}
SDValue Ops[] = { CmpLHS, InFlag.getOperand(1) };
SDValue LHS = Node->getOperand(0), RHS = Node->getOperand(1);
EVT VT = LHS.getValueType();
SDNode *Carry = CurDAG->getMachineNode(SLTuOp, DL, VT, Ops);
if (Subtarget->isGP64bit()) {
// On 64-bit targets, sltu produces an i64 but our backend currently says
// that SLTu64 produces an i32. We need to fix this in the long run but for
// now, just make the DAG type-correct by asserting the upper bits are zero.
Carry = CurDAG->getMachineNode(Mips::SUBREG_TO_REG, DL, VT,
CurDAG->getTargetConstant(0, DL, VT),
SDValue(Carry, 0),
CurDAG->getTargetConstant(Mips::sub_32, DL,
VT));
}
// Generate a second addition only if we know that RHS is not a
// constant-zero node.
SDNode *AddCarry = Carry;
ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS);
if (!C || C->getZExtValue())
AddCarry = CurDAG->getMachineNode(ADDuOp, DL, VT, SDValue(Carry, 0), RHS);
return CurDAG->SelectNodeTo(Node, MOp, VT, MVT::Glue, LHS,
SDValue(AddCarry, 0));
}
/// Match frameindex
bool MipsSEDAGToDAGISel::selectAddrFrameIndex(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
EVT ValTy = Addr.getValueType();
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), ValTy);
return true;
}
return false;
}
/// Match frameindex+offset and frameindex|offset
bool MipsSEDAGToDAGISel::selectAddrFrameIndexOffset(SDValue Addr, SDValue &Base,
SDValue &Offset,
unsigned OffsetBits) const {
if (CurDAG->isBaseWithConstantOffset(Addr)) {
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1));
if (isIntN(OffsetBits, CN->getSExtValue())) {
EVT ValTy = Addr.getValueType();
// 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(), SDLoc(Addr),
ValTy);
return true;
}
}
return false;
}
/// ComplexPattern used on MipsInstrInfo
/// Used on Mips Load/Store instructions
bool MipsSEDAGToDAGISel::selectAddrRegImm(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
// if Address is FI, get the TargetFrameIndex.
if (selectAddrFrameIndex(Addr, Base, Offset))
return true;
// on PIC code Load GA
if (Addr.getOpcode() == MipsISD::Wrapper) {
Base = Addr.getOperand(0);
Offset = Addr.getOperand(1);
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 (selectAddrFrameIndexOffset(Addr, Base, Offset, 16))
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 ||
Addr.getOperand(1).getOpcode() == MipsISD::GPRel) {
SDValue Opnd0 = Addr.getOperand(1).getOperand(0);
if (isa<ConstantPoolSDNode>(Opnd0) || isa<GlobalAddressSDNode>(Opnd0) ||
isa<JumpTableSDNode>(Opnd0)) {
Base = Addr.getOperand(0);
Offset = Opnd0;
return true;
}
}
}
return false;
}
/// ComplexPattern used on MipsInstrInfo
/// Used on Mips Load/Store instructions
bool MipsSEDAGToDAGISel::selectAddrRegReg(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
// Operand is a result from an ADD.
if (Addr.getOpcode() == ISD::ADD) {
Base = Addr.getOperand(0);
Offset = Addr.getOperand(1);
return true;
}
return false;
}
bool MipsSEDAGToDAGISel::selectAddrDefault(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
Base = Addr;
Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), Addr.getValueType());
return true;
}
bool MipsSEDAGToDAGISel::selectIntAddr(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
return selectAddrRegImm(Addr, Base, Offset) ||
selectAddrDefault(Addr, Base, Offset);
}
bool MipsSEDAGToDAGISel::selectAddrRegImm9(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
if (selectAddrFrameIndex(Addr, Base, Offset))
return true;
if (selectAddrFrameIndexOffset(Addr, Base, Offset, 9))
return true;
return false;
}
bool MipsSEDAGToDAGISel::selectAddrRegImm10(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
if (selectAddrFrameIndex(Addr, Base, Offset))
return true;
if (selectAddrFrameIndexOffset(Addr, Base, Offset, 10))
return true;
return false;
}
/// Used on microMIPS Load/Store unaligned instructions (12-bit offset)
bool MipsSEDAGToDAGISel::selectAddrRegImm12(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
if (selectAddrFrameIndex(Addr, Base, Offset))
return true;
if (selectAddrFrameIndexOffset(Addr, Base, Offset, 12))
return true;
return false;
}
bool MipsSEDAGToDAGISel::selectAddrRegImm16(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
if (selectAddrFrameIndex(Addr, Base, Offset))
return true;
if (selectAddrFrameIndexOffset(Addr, Base, Offset, 16))
return true;
return false;
}
bool MipsSEDAGToDAGISel::selectIntAddrMM(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
return selectAddrRegImm12(Addr, Base, Offset) ||
selectAddrDefault(Addr, Base, Offset);
}
bool MipsSEDAGToDAGISel::selectIntAddrLSL2MM(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
if (selectAddrFrameIndexOffset(Addr, Base, Offset, 7)) {
if (isa<FrameIndexSDNode>(Base))
return false;
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Offset)) {
unsigned CnstOff = CN->getZExtValue();
return (CnstOff == (CnstOff & 0x3c));
}
return false;
}
// For all other cases where "lw" would be selected, don't select "lw16"
// because it would result in additional instructions to prepare operands.
if (selectAddrRegImm(Addr, Base, Offset))
return false;
return selectAddrDefault(Addr, Base, Offset);
}
bool MipsSEDAGToDAGISel::selectIntAddrMSA(SDValue Addr, SDValue &Base,
SDValue &Offset) const {
if (selectAddrRegImm10(Addr, Base, Offset))
return true;
if (selectAddrDefault(Addr, Base, Offset))
return true;
return false;
}
// Select constant vector splats.
//
// Returns true and sets Imm if:
// * MSA is enabled
// * N is a ISD::BUILD_VECTOR representing a constant splat
bool MipsSEDAGToDAGISel::selectVSplat(SDNode *N, APInt &Imm,
unsigned MinSizeInBits) const {
if (!Subtarget->hasMSA())
return false;
BuildVectorSDNode *Node = dyn_cast<BuildVectorSDNode>(N);
if (!Node)
return false;
APInt SplatValue, SplatUndef;
unsigned SplatBitSize;
bool HasAnyUndefs;
if (!Node->isConstantSplat(SplatValue, SplatUndef, SplatBitSize, HasAnyUndefs,
MinSizeInBits, !Subtarget->isLittle()))
return false;
Imm = SplatValue;
return true;
}
// Select constant vector splats.
//
// In addition to the requirements of selectVSplat(), this function returns
// true and sets Imm if:
// * The splat value is the same width as the elements of the vector
// * The splat value fits in an integer with the specified signed-ness and
// width.
//
// This function looks through ISD::BITCAST nodes.
// TODO: This might not be appropriate for big-endian MSA since BITCAST is
// sometimes a shuffle in big-endian mode.
//
// It's worth noting that this function is not used as part of the selection
// of ldi.[bhwd] since it does not permit using the wrong-typed ldi.[bhwd]
// instruction to achieve the desired bit pattern. ldi.[bhwd] is selected in
// MipsSEDAGToDAGISel::selectNode.
bool MipsSEDAGToDAGISel::
selectVSplatCommon(SDValue N, SDValue &Imm, bool Signed,
unsigned ImmBitSize) const {
APInt ImmValue;
EVT EltTy = N->getValueType(0).getVectorElementType();
if (N->getOpcode() == ISD::BITCAST)
N = N->getOperand(0);
if (selectVSplat(N.getNode(), ImmValue, EltTy.getSizeInBits()) &&
ImmValue.getBitWidth() == EltTy.getSizeInBits()) {
if (( Signed && ImmValue.isSignedIntN(ImmBitSize)) ||
(!Signed && ImmValue.isIntN(ImmBitSize))) {
Imm = CurDAG->getTargetConstant(ImmValue, SDLoc(N), EltTy);
return true;
}
}
return false;
}
// Select constant vector splats.
bool MipsSEDAGToDAGISel::
selectVSplatUimm1(SDValue N, SDValue &Imm) const {
return selectVSplatCommon(N, Imm, false, 1);
}
bool MipsSEDAGToDAGISel::
selectVSplatUimm2(SDValue N, SDValue &Imm) const {
return selectVSplatCommon(N, Imm, false, 2);
}
bool MipsSEDAGToDAGISel::
selectVSplatUimm3(SDValue N, SDValue &Imm) const {
return selectVSplatCommon(N, Imm, false, 3);
}
// Select constant vector splats.
bool MipsSEDAGToDAGISel::
selectVSplatUimm4(SDValue N, SDValue &Imm) const {
return selectVSplatCommon(N, Imm, false, 4);
}
// Select constant vector splats.
bool MipsSEDAGToDAGISel::
selectVSplatUimm5(SDValue N, SDValue &Imm) const {
return selectVSplatCommon(N, Imm, false, 5);
}
// Select constant vector splats.
bool MipsSEDAGToDAGISel::
selectVSplatUimm6(SDValue N, SDValue &Imm) const {
return selectVSplatCommon(N, Imm, false, 6);
}
// Select constant vector splats.
bool MipsSEDAGToDAGISel::
selectVSplatUimm8(SDValue N, SDValue &Imm) const {
return selectVSplatCommon(N, Imm, false, 8);
}
// Select constant vector splats.
bool MipsSEDAGToDAGISel::
selectVSplatSimm5(SDValue N, SDValue &Imm) const {
return selectVSplatCommon(N, Imm, true, 5);
}
// Select constant vector splats whose value is a power of 2.
//
// In addition to the requirements of selectVSplat(), this function returns
// true and sets Imm if:
// * The splat value is the same width as the elements of the vector
// * The splat value is a power of two.
//
// This function looks through ISD::BITCAST nodes.
// TODO: This might not be appropriate for big-endian MSA since BITCAST is
// sometimes a shuffle in big-endian mode.
bool MipsSEDAGToDAGISel::selectVSplatUimmPow2(SDValue N, SDValue &Imm) const {
APInt ImmValue;
EVT EltTy = N->getValueType(0).getVectorElementType();
if (N->getOpcode() == ISD::BITCAST)
N = N->getOperand(0);
if (selectVSplat(N.getNode(), ImmValue, EltTy.getSizeInBits()) &&
ImmValue.getBitWidth() == EltTy.getSizeInBits()) {
int32_t Log2 = ImmValue.exactLogBase2();
if (Log2 != -1) {
Imm = CurDAG->getTargetConstant(Log2, SDLoc(N), EltTy);
return true;
}
}
return false;
}
// Select constant vector splats whose value only has a consecutive sequence
// of left-most bits set (e.g. 0b11...1100...00).
//
// In addition to the requirements of selectVSplat(), this function returns
// true and sets Imm if:
// * The splat value is the same width as the elements of the vector
// * The splat value is a consecutive sequence of left-most bits.
//
// This function looks through ISD::BITCAST nodes.
// TODO: This might not be appropriate for big-endian MSA since BITCAST is
// sometimes a shuffle in big-endian mode.
bool MipsSEDAGToDAGISel::selectVSplatMaskL(SDValue N, SDValue &Imm) const {
APInt ImmValue;
EVT EltTy = N->getValueType(0).getVectorElementType();
if (N->getOpcode() == ISD::BITCAST)
N = N->getOperand(0);
if (selectVSplat(N.getNode(), ImmValue, EltTy.getSizeInBits()) &&
ImmValue.getBitWidth() == EltTy.getSizeInBits()) {
// Extract the run of set bits starting with bit zero from the bitwise
// inverse of ImmValue, and test that the inverse of this is the same
// as the original value.
if (ImmValue == ~(~ImmValue & ~(~ImmValue + 1))) {
Imm = CurDAG->getTargetConstant(ImmValue.countPopulation(), SDLoc(N),
EltTy);
return true;
}
}
return false;
}
// Select constant vector splats whose value only has a consecutive sequence
// of right-most bits set (e.g. 0b00...0011...11).
//
// In addition to the requirements of selectVSplat(), this function returns
// true and sets Imm if:
// * The splat value is the same width as the elements of the vector
// * The splat value is a consecutive sequence of right-most bits.
//
// This function looks through ISD::BITCAST nodes.
// TODO: This might not be appropriate for big-endian MSA since BITCAST is
// sometimes a shuffle in big-endian mode.
bool MipsSEDAGToDAGISel::selectVSplatMaskR(SDValue N, SDValue &Imm) const {
APInt ImmValue;
EVT EltTy = N->getValueType(0).getVectorElementType();
if (N->getOpcode() == ISD::BITCAST)
N = N->getOperand(0);
if (selectVSplat(N.getNode(), ImmValue, EltTy.getSizeInBits()) &&
ImmValue.getBitWidth() == EltTy.getSizeInBits()) {
// Extract the run of set bits starting with bit zero, and test that the
// result is the same as the original value
if (ImmValue == (ImmValue & ~(ImmValue + 1))) {
Imm = CurDAG->getTargetConstant(ImmValue.countPopulation(), SDLoc(N),
EltTy);
return true;
}
}
return false;
}
bool MipsSEDAGToDAGISel::selectVSplatUimmInvPow2(SDValue N,
SDValue &Imm) const {
APInt ImmValue;
EVT EltTy = N->getValueType(0).getVectorElementType();
if (N->getOpcode() == ISD::BITCAST)
N = N->getOperand(0);
if (selectVSplat(N.getNode(), ImmValue, EltTy.getSizeInBits()) &&
ImmValue.getBitWidth() == EltTy.getSizeInBits()) {
int32_t Log2 = (~ImmValue).exactLogBase2();
if (Log2 != -1) {
Imm = CurDAG->getTargetConstant(Log2, SDLoc(N), EltTy);
return true;
}
}
return false;
}
std::pair<bool, SDNode*> MipsSEDAGToDAGISel::selectNode(SDNode *Node) {
unsigned Opcode = Node->getOpcode();
SDLoc DL(Node);
///
// Instruction Selection not handled by the auto-generated
// tablegen selection should be handled here.
///
SDNode *Result;
switch(Opcode) {
default: break;
case ISD::SUBE: {
SDValue InFlag = Node->getOperand(2);
unsigned Opc = Subtarget->isGP64bit() ? Mips::DSUBu : Mips::SUBu;
Result = selectAddESubE(Opc, InFlag, InFlag.getOperand(0), DL, Node);
return std::make_pair(true, Result);
}
case ISD::ADDE: {
if (Subtarget->hasDSP()) // Select DSP instructions, ADDSC and ADDWC.
break;
SDValue InFlag = Node->getOperand(2);
unsigned Opc = Subtarget->isGP64bit() ? Mips::DADDu : Mips::ADDu;
Result = selectAddESubE(Opc, InFlag, InFlag.getValue(0), DL, Node);
return std::make_pair(true, Result);
}
case ISD::ConstantFP: {
ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(Node);
if (Node->getValueType(0) == MVT::f64 && CN->isExactlyValue(+0.0)) {
if (Subtarget->isGP64bit()) {
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), DL,
Mips::ZERO_64, MVT::i64);
Result = CurDAG->getMachineNode(Mips::DMTC1, DL, MVT::f64, Zero);
} else if (Subtarget->isFP64bit()) {
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), DL,
Mips::ZERO, MVT::i32);
Result = CurDAG->getMachineNode(Mips::BuildPairF64_64, DL, MVT::f64,
Zero, Zero);
} else {
SDValue Zero = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), DL,
Mips::ZERO, MVT::i32);
Result = CurDAG->getMachineNode(Mips::BuildPairF64, DL, MVT::f64, Zero,
Zero);
}
return std::make_pair(true, Result);
}
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();
SDLoc DL(CN);
SDNode *RegOpnd;
SDValue ImmOpnd = CurDAG->getTargetConstant(SignExtend64<16>(Inst->ImmOpnd),
DL, 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), DL,
MVT::i64);
RegOpnd = CurDAG->getMachineNode(Inst->Opc, DL, MVT::i64,
SDValue(RegOpnd, 0), ImmOpnd);
}
return std::make_pair(true, RegOpnd);
}
case ISD::INTRINSIC_W_CHAIN: {
switch (cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue()) {
default:
break;
case Intrinsic::mips_cfcmsa: {
SDValue ChainIn = Node->getOperand(0);
SDValue RegIdx = Node->getOperand(2);
SDValue Reg = CurDAG->getCopyFromReg(ChainIn, DL,
getMSACtrlReg(RegIdx), MVT::i32);
return std::make_pair(true, Reg.getNode());
}
}
break;
}
case ISD::INTRINSIC_WO_CHAIN: {
switch (cast<ConstantSDNode>(Node->getOperand(0))->getZExtValue()) {
default:
break;
case Intrinsic::mips_move_v:
// Like an assignment but will always produce a move.v even if
// unnecessary.
return std::make_pair(true,
CurDAG->getMachineNode(Mips::MOVE_V, DL,
Node->getValueType(0),
Node->getOperand(1)));
}
break;
}
case ISD::INTRINSIC_VOID: {
switch (cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue()) {
default:
break;
case Intrinsic::mips_ctcmsa: {
SDValue ChainIn = Node->getOperand(0);
SDValue RegIdx = Node->getOperand(2);
SDValue Value = Node->getOperand(3);
SDValue ChainOut = CurDAG->getCopyToReg(ChainIn, DL,
getMSACtrlReg(RegIdx), Value);
return std::make_pair(true, ChainOut.getNode());
}
}
break;
}
case MipsISD::ThreadPointer: {
EVT PtrVT = getTargetLowering()->getPointerTy(CurDAG->getDataLayout());
unsigned RdhwrOpc, DestReg;
if (PtrVT == MVT::i32) {
RdhwrOpc = Mips::RDHWR;
DestReg = Mips::V1;
} else {
RdhwrOpc = Mips::RDHWR64;
DestReg = Mips::V1_64;
}
SDNode *Rdhwr =
CurDAG->getMachineNode(RdhwrOpc, DL,
Node->getValueType(0),
CurDAG->getRegister(Mips::HWR29, MVT::i32));
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 std::make_pair(true, ResNode.getNode());
}
case ISD::BUILD_VECTOR: {
// Select appropriate ldi.[bhwd] instructions for constant splats of
// 128-bit when MSA is enabled. Fixup any register class mismatches that
// occur as a result.
//
// This allows the compiler to use a wider range of immediates than would
// otherwise be allowed. If, for example, v4i32 could only use ldi.h then
// it would not be possible to load { 0x01010101, 0x01010101, 0x01010101,
// 0x01010101 } without using a constant pool. This would be sub-optimal
// when // 'ldi.b wd, 1' is capable of producing that bit-pattern in the
// same set/ of registers. Similarly, ldi.h isn't capable of producing {
// 0x00000000, 0x00000001, 0x00000000, 0x00000001 } but 'ldi.d wd, 1' can.
BuildVectorSDNode *BVN = cast<BuildVectorSDNode>(Node);
APInt SplatValue, SplatUndef;
unsigned SplatBitSize;
bool HasAnyUndefs;
unsigned LdiOp;
EVT ResVecTy = BVN->getValueType(0);
EVT ViaVecTy;
if (!Subtarget->hasMSA() || !BVN->getValueType(0).is128BitVector())
return std::make_pair(false, nullptr);
if (!BVN->isConstantSplat(SplatValue, SplatUndef, SplatBitSize,
HasAnyUndefs, 8,
!Subtarget->isLittle()))
return std::make_pair(false, nullptr);
switch (SplatBitSize) {
default:
return std::make_pair(false, nullptr);
case 8:
LdiOp = Mips::LDI_B;
ViaVecTy = MVT::v16i8;
break;
case 16:
LdiOp = Mips::LDI_H;
ViaVecTy = MVT::v8i16;
break;
case 32:
LdiOp = Mips::LDI_W;
ViaVecTy = MVT::v4i32;
break;
case 64:
LdiOp = Mips::LDI_D;
ViaVecTy = MVT::v2i64;
break;
}
if (!SplatValue.isSignedIntN(10))
return std::make_pair(false, nullptr);
SDValue Imm = CurDAG->getTargetConstant(SplatValue, DL,
ViaVecTy.getVectorElementType());
SDNode *Res = CurDAG->getMachineNode(LdiOp, DL, ViaVecTy, Imm);
if (ResVecTy != ViaVecTy) {
// If LdiOp is writing to a different register class to ResVecTy, then
// fix it up here. This COPY_TO_REGCLASS should never cause a move.v
// since the source and destination register sets contain the same
// registers.
const TargetLowering *TLI = getTargetLowering();
MVT ResVecTySimple = ResVecTy.getSimpleVT();
const TargetRegisterClass *RC = TLI->getRegClassFor(ResVecTySimple);
Res = CurDAG->getMachineNode(Mips::COPY_TO_REGCLASS, DL,
ResVecTy, SDValue(Res, 0),
CurDAG->getTargetConstant(RC->getID(), DL,
MVT::i32));
}
return std::make_pair(true, Res);
}
}
return std::make_pair(false, nullptr);
}
bool MipsSEDAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
std::vector<SDValue> &OutOps) {
SDValue Base, Offset;
switch(ConstraintID) {
default:
llvm_unreachable("Unexpected asm memory constraint");
// All memory constraints can at least accept raw pointers.
case InlineAsm::Constraint_i:
OutOps.push_back(Op);
OutOps.push_back(CurDAG->getTargetConstant(0, SDLoc(Op), MVT::i32));
return false;
case InlineAsm::Constraint_m:
if (selectAddrRegImm16(Op, Base, Offset)) {
OutOps.push_back(Base);
OutOps.push_back(Offset);
return false;
}
OutOps.push_back(Op);
OutOps.push_back(CurDAG->getTargetConstant(0, SDLoc(Op), MVT::i32));
return false;
case InlineAsm::Constraint_R:
// The 'R' constraint is supposed to be much more complicated than this.
// However, it's becoming less useful due to architectural changes and
// ought to be replaced by other constraints such as 'ZC'.
// For now, support 9-bit signed offsets which is supportable by all
// subtargets for all instructions.
if (selectAddrRegImm9(Op, Base, Offset)) {
OutOps.push_back(Base);
OutOps.push_back(Offset);
return false;
}
OutOps.push_back(Op);
OutOps.push_back(CurDAG->getTargetConstant(0, SDLoc(Op), MVT::i32));
return false;
case InlineAsm::Constraint_ZC:
// ZC matches whatever the pref, ll, and sc instructions can handle for the
// given subtarget.
if (Subtarget->inMicroMipsMode()) {
// On microMIPS, they can handle 12-bit offsets.
if (selectAddrRegImm12(Op, Base, Offset)) {
OutOps.push_back(Base);
OutOps.push_back(Offset);
return false;
}
} else if (Subtarget->hasMips32r6()) {
// On MIPS32r6/MIPS64r6, they can only handle 9-bit offsets.
if (selectAddrRegImm9(Op, Base, Offset)) {
OutOps.push_back(Base);
OutOps.push_back(Offset);
return false;
}
} else if (selectAddrRegImm16(Op, Base, Offset)) {
// Prior to MIPS32r6/MIPS64r6, they can handle 16-bit offsets.
OutOps.push_back(Base);
OutOps.push_back(Offset);
return false;
}
// In all cases, 0-bit offsets are acceptable.
OutOps.push_back(Op);
OutOps.push_back(CurDAG->getTargetConstant(0, SDLoc(Op), MVT::i32));
return false;
}
return true;
}
FunctionPass *llvm::createMipsSEISelDag(MipsTargetMachine &TM) {
return new MipsSEDAGToDAGISel(TM);
}
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