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llvm-6502/lib/Target/Mips/MipsSEISelDAGToDAG.cpp
Daniel Sanders dfce63b1ba [mips] Correct and improve special-case shuffle instructions. 
Summary:
The documentation writes vectors highest-index first whereas LLVM-IR writes
them lowest-index first. As a result, instructions defined in terms of
left_half() and right_half() had the halves reversed.

In addition to correcting them, they have been improved to allow shuffles
that use the same operand twice or in reverse order. For example, ilvev
used to accept masks of the form:
  <0, n, 2, n+2, 4, n+4, ...>
but now accepts:
  <0, 0, 2, 2, 4, 4, ...>
  <n, n, n+2, n+2, n+4, n+4, ...>
  <0, n, 2, n+2, 4, n+4, ...>
  <n, 0, n+2, 2, n+4, 4, ...>

One further improvement is that splati.[bhwd] is now the preferred instruction
for splat-like operations. The other special shuffles are no longer used
for splats. This lead to the discovery that <0, 0, ...> would not cause
splati.[hwd] to be selected and this has also been fixed.

This fixes the enc-3des test from the test-suite on Mips64r6 with MSA.

Reviewers: vkalintiris

Reviewed By: vkalintiris

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9660

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237689 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-19 12:24:52 +00:00

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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;
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 = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
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();
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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