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swiftshader / SwiftShader / 9c9608fa94a9209f2635c1d821c3652c3fd2a5e8 / . / third_party / llvm-16.0 / llvm / lib / Target / AVR / AVRISelLowering.cpp
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//===-- AVRISelLowering.cpp - AVR DAG Lowering Implementation -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the interfaces that AVR uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//
#include "AVRISelLowering.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/ErrorHandling.h"
#include "AVR.h"
#include "AVRMachineFunctionInfo.h"
#include "AVRSubtarget.h"
#include "AVRTargetMachine.h"
#include "MCTargetDesc/AVRMCTargetDesc.h"
namespace llvm {
AVRTargetLowering::AVRTargetLowering(const AVRTargetMachine &TM,
const AVRSubtarget &STI)
: TargetLowering(TM), Subtarget(STI) {
// Set up the register classes.
addRegisterClass(MVT::i8, &AVR::GPR8RegClass);
addRegisterClass(MVT::i16, &AVR::DREGSRegClass);
// Compute derived properties from the register classes.
computeRegisterProperties(Subtarget.getRegisterInfo());
setBooleanContents(ZeroOrOneBooleanContent);
setBooleanVectorContents(ZeroOrOneBooleanContent);
setSchedulingPreference(Sched::RegPressure);
setStackPointerRegisterToSaveRestore(AVR::SP);
setSupportsUnalignedAtomics(true);
setOperationAction(ISD::GlobalAddress, MVT::i16, Custom);
setOperationAction(ISD::BlockAddress, MVT::i16, Custom);
setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i8, Expand);
setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i16, Expand);
setOperationAction(ISD::INLINEASM, MVT::Other, Custom);
for (MVT VT : MVT::integer_valuetypes()) {
for (auto N : {ISD::EXTLOAD, ISD::SEXTLOAD, ISD::ZEXTLOAD}) {
setLoadExtAction(N, VT, MVT::i1, Promote);
setLoadExtAction(N, VT, MVT::i8, Expand);
}
}
setTruncStoreAction(MVT::i16, MVT::i8, Expand);
for (MVT VT : MVT::integer_valuetypes()) {
setOperationAction(ISD::ADDC, VT, Legal);
setOperationAction(ISD::SUBC, VT, Legal);
setOperationAction(ISD::ADDE, VT, Legal);
setOperationAction(ISD::SUBE, VT, Legal);
}
// sub (x, imm) gets canonicalized to add (x, -imm), so for illegal types
// revert into a sub since we don't have an add with immediate instruction.
setOperationAction(ISD::ADD, MVT::i32, Custom);
setOperationAction(ISD::ADD, MVT::i64, Custom);
// our shift instructions are only able to shift 1 bit at a time, so handle
// this in a custom way.
setOperationAction(ISD::SRA, MVT::i8, Custom);
setOperationAction(ISD::SHL, MVT::i8, Custom);
setOperationAction(ISD::SRL, MVT::i8, Custom);
setOperationAction(ISD::SRA, MVT::i16, Custom);
setOperationAction(ISD::SHL, MVT::i16, Custom);
setOperationAction(ISD::SRL, MVT::i16, Custom);
setOperationAction(ISD::SRA, MVT::i32, Custom);
setOperationAction(ISD::SHL, MVT::i32, Custom);
setOperationAction(ISD::SRL, MVT::i32, Custom);
setOperationAction(ISD::SHL_PARTS, MVT::i16, Expand);
setOperationAction(ISD::SRA_PARTS, MVT::i16, Expand);
setOperationAction(ISD::SRL_PARTS, MVT::i16, Expand);
setOperationAction(ISD::ROTL, MVT::i8, Custom);
setOperationAction(ISD::ROTL, MVT::i16, Expand);
setOperationAction(ISD::ROTR, MVT::i8, Custom);
setOperationAction(ISD::ROTR, MVT::i16, Expand);
setOperationAction(ISD::BR_CC, MVT::i8, Custom);
setOperationAction(ISD::BR_CC, MVT::i16, Custom);
setOperationAction(ISD::BR_CC, MVT::i32, Custom);
setOperationAction(ISD::BR_CC, MVT::i64, Custom);
setOperationAction(ISD::BRCOND, MVT::Other, Expand);
setOperationAction(ISD::SELECT_CC, MVT::i8, Custom);
setOperationAction(ISD::SELECT_CC, MVT::i16, Custom);
setOperationAction(ISD::SELECT_CC, MVT::i32, Expand);
setOperationAction(ISD::SELECT_CC, MVT::i64, Expand);
setOperationAction(ISD::SETCC, MVT::i8, Custom);
setOperationAction(ISD::SETCC, MVT::i16, Custom);
setOperationAction(ISD::SETCC, MVT::i32, Custom);
setOperationAction(ISD::SETCC, MVT::i64, Custom);
setOperationAction(ISD::SELECT, MVT::i8, Expand);
setOperationAction(ISD::SELECT, MVT::i16, Expand);
setOperationAction(ISD::BSWAP, MVT::i16, Expand);
// Add support for postincrement and predecrement load/stores.
setIndexedLoadAction(ISD::POST_INC, MVT::i8, Legal);
setIndexedLoadAction(ISD::POST_INC, MVT::i16, Legal);
setIndexedLoadAction(ISD::PRE_DEC, MVT::i8, Legal);
setIndexedLoadAction(ISD::PRE_DEC, MVT::i16, Legal);
setIndexedStoreAction(ISD::POST_INC, MVT::i8, Legal);
setIndexedStoreAction(ISD::POST_INC, MVT::i16, Legal);
setIndexedStoreAction(ISD::PRE_DEC, MVT::i8, Legal);
setIndexedStoreAction(ISD::PRE_DEC, MVT::i16, Legal);
setOperationAction(ISD::BR_JT, MVT::Other, Expand);
setOperationAction(ISD::VASTART, MVT::Other, Custom);
setOperationAction(ISD::VAEND, MVT::Other, Expand);
setOperationAction(ISD::VAARG, MVT::Other, Expand);
setOperationAction(ISD::VACOPY, MVT::Other, Expand);
// Atomic operations which must be lowered to rtlib calls
for (MVT VT : MVT::integer_valuetypes()) {
setOperationAction(ISD::ATOMIC_SWAP, VT, Expand);
setOperationAction(ISD::ATOMIC_CMP_SWAP, VT, Expand);
setOperationAction(ISD::ATOMIC_LOAD_NAND, VT, Expand);
setOperationAction(ISD::ATOMIC_LOAD_MAX, VT, Expand);
setOperationAction(ISD::ATOMIC_LOAD_MIN, VT, Expand);
setOperationAction(ISD::ATOMIC_LOAD_UMAX, VT, Expand);
setOperationAction(ISD::ATOMIC_LOAD_UMIN, VT, Expand);
}
// Division/remainder
setOperationAction(ISD::UDIV, MVT::i8, Expand);
setOperationAction(ISD::UDIV, MVT::i16, Expand);
setOperationAction(ISD::UREM, MVT::i8, Expand);
setOperationAction(ISD::UREM, MVT::i16, Expand);
setOperationAction(ISD::SDIV, MVT::i8, Expand);
setOperationAction(ISD::SDIV, MVT::i16, Expand);
setOperationAction(ISD::SREM, MVT::i8, Expand);
setOperationAction(ISD::SREM, MVT::i16, Expand);
// Make division and modulus custom
setOperationAction(ISD::UDIVREM, MVT::i8, Custom);
setOperationAction(ISD::UDIVREM, MVT::i16, Custom);
setOperationAction(ISD::UDIVREM, MVT::i32, Custom);
setOperationAction(ISD::SDIVREM, MVT::i8, Custom);
setOperationAction(ISD::SDIVREM, MVT::i16, Custom);
setOperationAction(ISD::SDIVREM, MVT::i32, Custom);
// Do not use MUL. The AVR instructions are closer to SMUL_LOHI &co.
setOperationAction(ISD::MUL, MVT::i8, Expand);
setOperationAction(ISD::MUL, MVT::i16, Expand);
// Expand 16 bit multiplications.
setOperationAction(ISD::SMUL_LOHI, MVT::i16, Expand);
setOperationAction(ISD::UMUL_LOHI, MVT::i16, Expand);
// Expand multiplications to libcalls when there is
// no hardware MUL.
if (!Subtarget.supportsMultiplication()) {
setOperationAction(ISD::SMUL_LOHI, MVT::i8, Expand);
setOperationAction(ISD::UMUL_LOHI, MVT::i8, Expand);
}
for (MVT VT : MVT::integer_valuetypes()) {
setOperationAction(ISD::MULHS, VT, Expand);
setOperationAction(ISD::MULHU, VT, Expand);
}
for (MVT VT : MVT::integer_valuetypes()) {
setOperationAction(ISD::CTPOP, VT, Expand);
setOperationAction(ISD::CTLZ, VT, Expand);
setOperationAction(ISD::CTTZ, VT, Expand);
}
for (MVT VT : MVT::integer_valuetypes()) {
setOperationAction(ISD::SIGN_EXTEND_INREG, VT, Expand);
// TODO: The generated code is pretty poor. Investigate using the
// same "shift and subtract with carry" trick that we do for
// extending 8-bit to 16-bit. This may require infrastructure
// improvements in how we treat 16-bit "registers" to be feasible.
}
// Division rtlib functions (not supported), use divmod functions instead
setLibcallName(RTLIB::SDIV_I8, nullptr);
setLibcallName(RTLIB::SDIV_I16, nullptr);
setLibcallName(RTLIB::SDIV_I32, nullptr);
setLibcallName(RTLIB::UDIV_I8, nullptr);
setLibcallName(RTLIB::UDIV_I16, nullptr);
setLibcallName(RTLIB::UDIV_I32, nullptr);
// Modulus rtlib functions (not supported), use divmod functions instead
setLibcallName(RTLIB::SREM_I8, nullptr);
setLibcallName(RTLIB::SREM_I16, nullptr);
setLibcallName(RTLIB::SREM_I32, nullptr);
setLibcallName(RTLIB::UREM_I8, nullptr);
setLibcallName(RTLIB::UREM_I16, nullptr);
setLibcallName(RTLIB::UREM_I32, nullptr);
// Division and modulus rtlib functions
setLibcallName(RTLIB::SDIVREM_I8, "__divmodqi4");
setLibcallName(RTLIB::SDIVREM_I16, "__divmodhi4");
setLibcallName(RTLIB::SDIVREM_I32, "__divmodsi4");
setLibcallName(RTLIB::UDIVREM_I8, "__udivmodqi4");
setLibcallName(RTLIB::UDIVREM_I16, "__udivmodhi4");
setLibcallName(RTLIB::UDIVREM_I32, "__udivmodsi4");
// Several of the runtime library functions use a special calling conv
setLibcallCallingConv(RTLIB::SDIVREM_I8, CallingConv::AVR_BUILTIN);
setLibcallCallingConv(RTLIB::SDIVREM_I16, CallingConv::AVR_BUILTIN);
setLibcallCallingConv(RTLIB::UDIVREM_I8, CallingConv::AVR_BUILTIN);
setLibcallCallingConv(RTLIB::UDIVREM_I16, CallingConv::AVR_BUILTIN);
// Trigonometric rtlib functions
setLibcallName(RTLIB::SIN_F32, "sin");
setLibcallName(RTLIB::COS_F32, "cos");
setMinFunctionAlignment(Align(2));
setMinimumJumpTableEntries(UINT_MAX);
}
const char *AVRTargetLowering::getTargetNodeName(unsigned Opcode) const {
#define NODE(name) \
case AVRISD::name: \
return #name
switch (Opcode) {
default:
return nullptr;
NODE(RET_FLAG);
NODE(RETI_FLAG);
NODE(CALL);
NODE(WRAPPER);
NODE(LSL);
NODE(LSLW);
NODE(LSR);
NODE(LSRW);
NODE(ROL);
NODE(ROR);
NODE(ASR);
NODE(ASRW);
NODE(LSLLOOP);
NODE(LSRLOOP);
NODE(ROLLOOP);
NODE(RORLOOP);
NODE(ASRLOOP);
NODE(BRCOND);
NODE(CMP);
NODE(CMPC);
NODE(TST);
NODE(SELECT_CC);
#undef NODE
}
}
EVT AVRTargetLowering::getSetCCResultType(const DataLayout &DL, LLVMContext &,
EVT VT) const {
assert(!VT.isVector() && "No AVR SetCC type for vectors!");
return MVT::i8;
}
SDValue AVRTargetLowering::LowerShifts(SDValue Op, SelectionDAG &DAG) const {
unsigned Opc8;
const SDNode *N = Op.getNode();
EVT VT = Op.getValueType();
SDLoc dl(N);
assert(isPowerOf2_32(VT.getSizeInBits()) &&
"Expected power-of-2 shift amount");
if (VT.getSizeInBits() == 32) {
if (!isa<ConstantSDNode>(N->getOperand(1))) {
// 32-bit shifts are converted to a loop in IR.
// This should be unreachable.
report_fatal_error("Expected a constant shift amount!");
}
SDVTList ResTys = DAG.getVTList(MVT::i16, MVT::i16);
SDValue SrcLo =
DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i16, Op.getOperand(0),
DAG.getConstant(0, dl, MVT::i16));
SDValue SrcHi =
DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i16, Op.getOperand(0),
DAG.getConstant(1, dl, MVT::i16));
uint64_t ShiftAmount =
cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
if (ShiftAmount == 16) {
// Special case these two operations because they appear to be used by the
// generic codegen parts to lower 32-bit numbers.
// TODO: perhaps we can lower shift amounts bigger than 16 to a 16-bit
// shift of a part of the 32-bit value?
switch (Op.getOpcode()) {
case ISD::SHL: {
SDValue Zero = DAG.getConstant(0, dl, MVT::i16);
return DAG.getNode(ISD::BUILD_PAIR, dl, MVT::i32, Zero, SrcLo);
}
case ISD::SRL: {
SDValue Zero = DAG.getConstant(0, dl, MVT::i16);
return DAG.getNode(ISD::BUILD_PAIR, dl, MVT::i32, SrcHi, Zero);
}
}
}
SDValue Cnt = DAG.getTargetConstant(ShiftAmount, dl, MVT::i8);
unsigned Opc;
switch (Op.getOpcode()) {
default:
llvm_unreachable("Invalid 32-bit shift opcode!");
case ISD::SHL:
Opc = AVRISD::LSLW;
break;
case ISD::SRL:
Opc = AVRISD::LSRW;
break;
case ISD::SRA:
Opc = AVRISD::ASRW;
break;
}
SDValue Result = DAG.getNode(Opc, dl, ResTys, SrcLo, SrcHi, Cnt);
return DAG.getNode(ISD::BUILD_PAIR, dl, MVT::i32, Result.getValue(0),
Result.getValue(1));
}
// Expand non-constant shifts to loops.
if (!isa<ConstantSDNode>(N->getOperand(1))) {
switch (Op.getOpcode()) {
default:
llvm_unreachable("Invalid shift opcode!");
case ISD::SHL:
return DAG.getNode(AVRISD::LSLLOOP, dl, VT, N->getOperand(0),
N->getOperand(1));
case ISD::SRL:
return DAG.getNode(AVRISD::LSRLOOP, dl, VT, N->getOperand(0),
N->getOperand(1));
case ISD::ROTL: {
SDValue Amt = N->getOperand(1);
EVT AmtVT = Amt.getValueType();
Amt = DAG.getNode(ISD::AND, dl, AmtVT, Amt,
DAG.getConstant(VT.getSizeInBits() - 1, dl, AmtVT));
return DAG.getNode(AVRISD::ROLLOOP, dl, VT, N->getOperand(0), Amt);
}
case ISD::ROTR: {
SDValue Amt = N->getOperand(1);
EVT AmtVT = Amt.getValueType();
Amt = DAG.getNode(ISD::AND, dl, AmtVT, Amt,
DAG.getConstant(VT.getSizeInBits() - 1, dl, AmtVT));
return DAG.getNode(AVRISD::RORLOOP, dl, VT, N->getOperand(0), Amt);
}
case ISD::SRA:
return DAG.getNode(AVRISD::ASRLOOP, dl, VT, N->getOperand(0),
N->getOperand(1));
}
}
uint64_t ShiftAmount = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
SDValue Victim = N->getOperand(0);
switch (Op.getOpcode()) {
case ISD::SRA:
Opc8 = AVRISD::ASR;
break;
case ISD::ROTL:
Opc8 = AVRISD::ROL;
ShiftAmount = ShiftAmount % VT.getSizeInBits();
break;
case ISD::ROTR:
Opc8 = AVRISD::ROR;
ShiftAmount = ShiftAmount % VT.getSizeInBits();
break;
case ISD::SRL:
Opc8 = AVRISD::LSR;
break;
case ISD::SHL:
Opc8 = AVRISD::LSL;
break;
default:
llvm_unreachable("Invalid shift opcode");
}
// Optimize int8/int16 shifts.
if (VT.getSizeInBits() == 8) {
if (Op.getOpcode() == ISD::SHL && 4 <= ShiftAmount && ShiftAmount < 7) {
// Optimize LSL when 4 <= ShiftAmount <= 6.
Victim = DAG.getNode(AVRISD::SWAP, dl, VT, Victim);
Victim =
DAG.getNode(ISD::AND, dl, VT, Victim, DAG.getConstant(0xf0, dl, VT));
ShiftAmount -= 4;
} else if (Op.getOpcode() == ISD::SRL && 4 <= ShiftAmount &&
ShiftAmount < 7) {
// Optimize LSR when 4 <= ShiftAmount <= 6.
Victim = DAG.getNode(AVRISD::SWAP, dl, VT, Victim);
Victim =
DAG.getNode(ISD::AND, dl, VT, Victim, DAG.getConstant(0x0f, dl, VT));
ShiftAmount -= 4;
} else if (Op.getOpcode() == ISD::SHL && ShiftAmount == 7) {
// Optimize LSL when ShiftAmount == 7.
Victim = DAG.getNode(AVRISD::LSLBN, dl, VT, Victim,
DAG.getConstant(7, dl, VT));
ShiftAmount = 0;
} else if (Op.getOpcode() == ISD::SRL && ShiftAmount == 7) {
// Optimize LSR when ShiftAmount == 7.
Victim = DAG.getNode(AVRISD::LSRBN, dl, VT, Victim,
DAG.getConstant(7, dl, VT));
ShiftAmount = 0;
} else if (Op.getOpcode() == ISD::SRA && ShiftAmount == 6) {
// Optimize ASR when ShiftAmount == 6.
Victim = DAG.getNode(AVRISD::ASRBN, dl, VT, Victim,
DAG.getConstant(6, dl, VT));
ShiftAmount = 0;
} else if (Op.getOpcode() == ISD::SRA && ShiftAmount == 7) {
// Optimize ASR when ShiftAmount == 7.
Victim = DAG.getNode(AVRISD::ASRBN, dl, VT, Victim,
DAG.getConstant(7, dl, VT));
ShiftAmount = 0;
}
} else if (VT.getSizeInBits() == 16) {
if (Op.getOpcode() == ISD::SRA)
// Special optimization for int16 arithmetic right shift.
switch (ShiftAmount) {
case 15:
Victim = DAG.getNode(AVRISD::ASRWN, dl, VT, Victim,
DAG.getConstant(15, dl, VT));
ShiftAmount = 0;
break;
case 14:
Victim = DAG.getNode(AVRISD::ASRWN, dl, VT, Victim,
DAG.getConstant(14, dl, VT));
ShiftAmount = 0;
break;
case 7:
Victim = DAG.getNode(AVRISD::ASRWN, dl, VT, Victim,
DAG.getConstant(7, dl, VT));
ShiftAmount = 0;
break;
default:
break;
}
if (4 <= ShiftAmount && ShiftAmount < 8)
switch (Op.getOpcode()) {
case ISD::SHL:
Victim = DAG.getNode(AVRISD::LSLWN, dl, VT, Victim,
DAG.getConstant(4, dl, VT));
ShiftAmount -= 4;
break;
case ISD::SRL:
Victim = DAG.getNode(AVRISD::LSRWN, dl, VT, Victim,
DAG.getConstant(4, dl, VT));
ShiftAmount -= 4;
break;
default:
break;
}
else if (8 <= ShiftAmount && ShiftAmount < 12)
switch (Op.getOpcode()) {
case ISD::SHL:
Victim = DAG.getNode(AVRISD::LSLWN, dl, VT, Victim,
DAG.getConstant(8, dl, VT));
ShiftAmount -= 8;
// Only operate on the higher byte for remaining shift bits.
Opc8 = AVRISD::LSLHI;
break;
case ISD::SRL:
Victim = DAG.getNode(AVRISD::LSRWN, dl, VT, Victim,
DAG.getConstant(8, dl, VT));
ShiftAmount -= 8;
// Only operate on the lower byte for remaining shift bits.
Opc8 = AVRISD::LSRLO;
break;
case ISD::SRA:
Victim = DAG.getNode(AVRISD::ASRWN, dl, VT, Victim,
DAG.getConstant(8, dl, VT));
ShiftAmount -= 8;
// Only operate on the lower byte for remaining shift bits.
Opc8 = AVRISD::ASRLO;
break;
default:
break;
}
else if (12 <= ShiftAmount)
switch (Op.getOpcode()) {
case ISD::SHL:
Victim = DAG.getNode(AVRISD::LSLWN, dl, VT, Victim,
DAG.getConstant(12, dl, VT));
ShiftAmount -= 12;
// Only operate on the higher byte for remaining shift bits.
Opc8 = AVRISD::LSLHI;
break;
case ISD::SRL:
Victim = DAG.getNode(AVRISD::LSRWN, dl, VT, Victim,
DAG.getConstant(12, dl, VT));
ShiftAmount -= 12;
// Only operate on the lower byte for remaining shift bits.
Opc8 = AVRISD::LSRLO;
break;
case ISD::SRA:
Victim = DAG.getNode(AVRISD::ASRWN, dl, VT, Victim,
DAG.getConstant(8, dl, VT));
ShiftAmount -= 8;
// Only operate on the lower byte for remaining shift bits.
Opc8 = AVRISD::ASRLO;
break;
default:
break;
}
}
while (ShiftAmount--) {
Victim = DAG.getNode(Opc8, dl, VT, Victim);
}
return Victim;
}
SDValue AVRTargetLowering::LowerDivRem(SDValue Op, SelectionDAG &DAG) const {
unsigned Opcode = Op->getOpcode();
assert((Opcode == ISD::SDIVREM || Opcode == ISD::UDIVREM) &&
"Invalid opcode for Div/Rem lowering");
bool IsSigned = (Opcode == ISD::SDIVREM);
EVT VT = Op->getValueType(0);
Type *Ty = VT.getTypeForEVT(*DAG.getContext());
RTLIB::Libcall LC;
switch (VT.getSimpleVT().SimpleTy) {
default:
llvm_unreachable("Unexpected request for libcall!");
case MVT::i8:
LC = IsSigned ? RTLIB::SDIVREM_I8 : RTLIB::UDIVREM_I8;
break;
case MVT::i16:
LC = IsSigned ? RTLIB::SDIVREM_I16 : RTLIB::UDIVREM_I16;
break;
case MVT::i32:
LC = IsSigned ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32;
break;
}
SDValue InChain = DAG.getEntryNode();
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
for (SDValue const &Value : Op->op_values()) {
Entry.Node = Value;
Entry.Ty = Value.getValueType().getTypeForEVT(*DAG.getContext());
Entry.IsSExt = IsSigned;
Entry.IsZExt = !IsSigned;
Args.push_back(Entry);
}
SDValue Callee = DAG.getExternalSymbol(getLibcallName(LC),
getPointerTy(DAG.getDataLayout()));
Type *RetTy = (Type *)StructType::get(Ty, Ty);
SDLoc dl(Op);
TargetLowering::CallLoweringInfo CLI(DAG);
CLI.setDebugLoc(dl)
.setChain(InChain)
.setLibCallee(getLibcallCallingConv(LC), RetTy, Callee, std::move(Args))
.setInRegister()
.setSExtResult(IsSigned)
.setZExtResult(!IsSigned);
std::pair<SDValue, SDValue> CallInfo = LowerCallTo(CLI);
return CallInfo.first;
}
SDValue AVRTargetLowering::LowerGlobalAddress(SDValue Op,
SelectionDAG &DAG) const {
auto DL = DAG.getDataLayout();
const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
// Create the TargetGlobalAddress node, folding in the constant offset.
SDValue Result =
DAG.getTargetGlobalAddress(GV, SDLoc(Op), getPointerTy(DL), Offset);
return DAG.getNode(AVRISD::WRAPPER, SDLoc(Op), getPointerTy(DL), Result);
}
SDValue AVRTargetLowering::LowerBlockAddress(SDValue Op,
SelectionDAG &DAG) const {
auto DL = DAG.getDataLayout();
const BlockAddress *BA = cast<BlockAddressSDNode>(Op)->getBlockAddress();
SDValue Result = DAG.getTargetBlockAddress(BA, getPointerTy(DL));
return DAG.getNode(AVRISD::WRAPPER, SDLoc(Op), getPointerTy(DL), Result);
}
/// IntCCToAVRCC - Convert a DAG integer condition code to an AVR CC.
static AVRCC::CondCodes intCCToAVRCC(ISD::CondCode CC) {
switch (CC) {
default:
llvm_unreachable("Unknown condition code!");
case ISD::SETEQ:
return AVRCC::COND_EQ;
case ISD::SETNE:
return AVRCC::COND_NE;
case ISD::SETGE:
return AVRCC::COND_GE;
case ISD::SETLT:
return AVRCC::COND_LT;
case ISD::SETUGE:
return AVRCC::COND_SH;
case ISD::SETULT:
return AVRCC::COND_LO;
}
}
/// Returns appropriate CP/CPI/CPC nodes code for the given 8/16-bit operands.
SDValue AVRTargetLowering::getAVRCmp(SDValue LHS, SDValue RHS,
SelectionDAG &DAG, SDLoc DL) const {
assert((LHS.getSimpleValueType() == RHS.getSimpleValueType()) &&
"LHS and RHS have different types");
assert(((LHS.getSimpleValueType() == MVT::i16) ||
(LHS.getSimpleValueType() == MVT::i8)) &&
"invalid comparison type");
SDValue Cmp;
if (LHS.getSimpleValueType() == MVT::i16 && isa<ConstantSDNode>(RHS)) {
// Generate a CPI/CPC pair if RHS is a 16-bit constant.
SDValue LHSlo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i8, LHS,
DAG.getIntPtrConstant(0, DL));
SDValue LHShi = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i8, LHS,
DAG.getIntPtrConstant(1, DL));
SDValue RHSlo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i8, RHS,
DAG.getIntPtrConstant(0, DL));
SDValue RHShi = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i8, RHS,
DAG.getIntPtrConstant(1, DL));
Cmp = DAG.getNode(AVRISD::CMP, DL, MVT::Glue, LHSlo, RHSlo);
Cmp = DAG.getNode(AVRISD::CMPC, DL, MVT::Glue, LHShi, RHShi, Cmp);
} else {
// Generate ordinary 16-bit comparison.
Cmp = DAG.getNode(AVRISD::CMP, DL, MVT::Glue, LHS, RHS);
}
return Cmp;
}
/// Returns appropriate AVR CMP/CMPC nodes and corresponding condition code for
/// the given operands.
SDValue AVRTargetLowering::getAVRCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
SDValue &AVRcc, SelectionDAG &DAG,
SDLoc DL) const {
SDValue Cmp;
EVT VT = LHS.getValueType();
bool UseTest = false;
switch (CC) {
default:
break;
case ISD::SETLE: {
// Swap operands and reverse the branching condition.
std::swap(LHS, RHS);
CC = ISD::SETGE;
break;
}
case ISD::SETGT: {
if (const ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS)) {
switch (C->getSExtValue()) {
case -1: {
// When doing lhs > -1 use a tst instruction on the top part of lhs
// and use brpl instead of using a chain of cp/cpc.
UseTest = true;
AVRcc = DAG.getConstant(AVRCC::COND_PL, DL, MVT::i8);
break;
}
case 0: {
// Turn lhs > 0 into 0 < lhs since 0 can be materialized with
// __zero_reg__ in lhs.
RHS = LHS;
LHS = DAG.getConstant(0, DL, VT);
CC = ISD::SETLT;
break;
}
default: {
// Turn lhs < rhs with lhs constant into rhs >= lhs+1, this allows
// us to fold the constant into the cmp instruction.
RHS = DAG.getConstant(C->getSExtValue() + 1, DL, VT);
CC = ISD::SETGE;
break;
}
}
break;
}
// Swap operands and reverse the branching condition.
std::swap(LHS, RHS);
CC = ISD::SETLT;
break;
}
case ISD::SETLT: {
if (const ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS)) {
switch (C->getSExtValue()) {
case 1: {
// Turn lhs < 1 into 0 >= lhs since 0 can be materialized with
// __zero_reg__ in lhs.
RHS = LHS;
LHS = DAG.getConstant(0, DL, VT);
CC = ISD::SETGE;
break;
}
case 0: {
// When doing lhs < 0 use a tst instruction on the top part of lhs
// and use brmi instead of using a chain of cp/cpc.
UseTest = true;
AVRcc = DAG.getConstant(AVRCC::COND_MI, DL, MVT::i8);
break;
}
}
}
break;
}
case ISD::SETULE: {
// Swap operands and reverse the branching condition.
std::swap(LHS, RHS);
CC = ISD::SETUGE;
break;
}
case ISD::SETUGT: {
// Turn lhs < rhs with lhs constant into rhs >= lhs+1, this allows us to
// fold the constant into the cmp instruction.
if (const ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS)) {
RHS = DAG.getConstant(C->getSExtValue() + 1, DL, VT);
CC = ISD::SETUGE;
break;
}
// Swap operands and reverse the branching condition.
std::swap(LHS, RHS);
CC = ISD::SETULT;
break;
}
}
// Expand 32 and 64 bit comparisons with custom CMP and CMPC nodes instead of
// using the default and/or/xor expansion code which is much longer.
if (VT == MVT::i32) {
SDValue LHSlo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, LHS,
DAG.getIntPtrConstant(0, DL));
SDValue LHShi = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, LHS,
DAG.getIntPtrConstant(1, DL));
SDValue RHSlo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, RHS,
DAG.getIntPtrConstant(0, DL));
SDValue RHShi = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, RHS,
DAG.getIntPtrConstant(1, DL));
if (UseTest) {
// When using tst we only care about the highest part.
SDValue Top = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i8, LHShi,
DAG.getIntPtrConstant(1, DL));
Cmp = DAG.getNode(AVRISD::TST, DL, MVT::Glue, Top);
} else {
Cmp = getAVRCmp(LHSlo, RHSlo, DAG, DL);
Cmp = DAG.getNode(AVRISD::CMPC, DL, MVT::Glue, LHShi, RHShi, Cmp);
}
} else if (VT == MVT::i64) {
SDValue LHS_0 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i32, LHS,
DAG.getIntPtrConstant(0, DL));
SDValue LHS_1 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i32, LHS,
DAG.getIntPtrConstant(1, DL));
SDValue LHS0 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, LHS_0,
DAG.getIntPtrConstant(0, DL));
SDValue LHS1 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, LHS_0,
DAG.getIntPtrConstant(1, DL));
SDValue LHS2 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, LHS_1,
DAG.getIntPtrConstant(0, DL));
SDValue LHS3 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, LHS_1,
DAG.getIntPtrConstant(1, DL));
SDValue RHS_0 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i32, RHS,
DAG.getIntPtrConstant(0, DL));
SDValue RHS_1 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i32, RHS,
DAG.getIntPtrConstant(1, DL));
SDValue RHS0 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, RHS_0,
DAG.getIntPtrConstant(0, DL));
SDValue RHS1 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, RHS_0,
DAG.getIntPtrConstant(1, DL));
SDValue RHS2 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, RHS_1,
DAG.getIntPtrConstant(0, DL));
SDValue RHS3 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i16, RHS_1,
DAG.getIntPtrConstant(1, DL));
if (UseTest) {
// When using tst we only care about the highest part.
SDValue Top = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i8, LHS3,
DAG.getIntPtrConstant(1, DL));
Cmp = DAG.getNode(AVRISD::TST, DL, MVT::Glue, Top);
} else {
Cmp = getAVRCmp(LHS0, RHS0, DAG, DL);
Cmp = DAG.getNode(AVRISD::CMPC, DL, MVT::Glue, LHS1, RHS1, Cmp);
Cmp = DAG.getNode(AVRISD::CMPC, DL, MVT::Glue, LHS2, RHS2, Cmp);
Cmp = DAG.getNode(AVRISD::CMPC, DL, MVT::Glue, LHS3, RHS3, Cmp);
}
} else if (VT == MVT::i8 || VT == MVT::i16) {
if (UseTest) {
// When using tst we only care about the highest part.
Cmp = DAG.getNode(AVRISD::TST, DL, MVT::Glue,
(VT == MVT::i8)
? LHS
: DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i8,
LHS, DAG.getIntPtrConstant(1, DL)));
} else {
Cmp = getAVRCmp(LHS, RHS, DAG, DL);
}
} else {
llvm_unreachable("Invalid comparison size");
}
// When using a test instruction AVRcc is already set.
if (!UseTest) {
AVRcc = DAG.getConstant(intCCToAVRCC(CC), DL, MVT::i8);
}
return Cmp;
}
SDValue AVRTargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) const {
SDValue Chain = Op.getOperand(0);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(1))->get();
SDValue LHS = Op.getOperand(2);
SDValue RHS = Op.getOperand(3);
SDValue Dest = Op.getOperand(4);
SDLoc dl(Op);
SDValue TargetCC;
SDValue Cmp = getAVRCmp(LHS, RHS, CC, TargetCC, DAG, dl);
return DAG.getNode(AVRISD::BRCOND, dl, MVT::Other, Chain, Dest, TargetCC,
Cmp);
}
SDValue AVRTargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const {
SDValue LHS = Op.getOperand(0);
SDValue RHS = Op.getOperand(1);
SDValue TrueV = Op.getOperand(2);
SDValue FalseV = Op.getOperand(3);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(4))->get();
SDLoc dl(Op);
SDValue TargetCC;
SDValue Cmp = getAVRCmp(LHS, RHS, CC, TargetCC, DAG, dl);
SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
SDValue Ops[] = {TrueV, FalseV, TargetCC, Cmp};
return DAG.getNode(AVRISD::SELECT_CC, dl, VTs, Ops);
}
SDValue AVRTargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) const {
SDValue LHS = Op.getOperand(0);
SDValue RHS = Op.getOperand(1);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
SDLoc DL(Op);
SDValue TargetCC;
SDValue Cmp = getAVRCmp(LHS, RHS, CC, TargetCC, DAG, DL);
SDValue TrueV = DAG.getConstant(1, DL, Op.getValueType());
SDValue FalseV = DAG.getConstant(0, DL, Op.getValueType());
SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
SDValue Ops[] = {TrueV, FalseV, TargetCC, Cmp};
return DAG.getNode(AVRISD::SELECT_CC, DL, VTs, Ops);
}
SDValue AVRTargetLowering::LowerVASTART(SDValue Op, SelectionDAG &DAG) const {
const MachineFunction &MF = DAG.getMachineFunction();
const AVRMachineFunctionInfo *AFI = MF.getInfo<AVRMachineFunctionInfo>();
const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
auto DL = DAG.getDataLayout();
SDLoc dl(Op);
// Vastart just stores the address of the VarArgsFrameIndex slot into the
// memory location argument.
SDValue FI = DAG.getFrameIndex(AFI->getVarArgsFrameIndex(), getPointerTy(DL));
return DAG.getStore(Op.getOperand(0), dl, FI, Op.getOperand(1),
MachinePointerInfo(SV));
}
// Modify the existing ISD::INLINEASM node to add the implicit zero register.
SDValue AVRTargetLowering::LowerINLINEASM(SDValue Op, SelectionDAG &DAG) const {
SDValue ZeroReg = DAG.getRegister(Subtarget.getZeroRegister(), MVT::i8);
if (Op.getOperand(Op.getNumOperands() - 1) == ZeroReg ||
Op.getOperand(Op.getNumOperands() - 2) == ZeroReg) {
// Zero register has already been added. Don't add it again.
// If this isn't handled, we get called over and over again.
return Op;
}
// Get a list of operands to the new INLINEASM node. This is mostly a copy,
// with some edits.
// Add the following operands at the end (but before the glue node, if it's
// there):
// - The flags of the implicit zero register operand.
// - The implicit zero register operand itself.
SDLoc dl(Op);
SmallVector<SDValue, 8> Ops;
SDNode *N = Op.getNode();
SDValue Glue;
for (unsigned I = 0; I < N->getNumOperands(); I++) {
SDValue Operand = N->getOperand(I);
if (Operand.getValueType() == MVT::Glue) {
// The glue operand always needs to be at the end, so we need to treat it
// specially.
Glue = Operand;
} else {
Ops.push_back(Operand);
}
}
unsigned Flags = InlineAsm::getFlagWord(InlineAsm::Kind_RegUse, 1);
Ops.push_back(DAG.getTargetConstant(Flags, dl, MVT::i32));
Ops.push_back(ZeroReg);
if (Glue) {
Ops.push_back(Glue);
}
// Replace the current INLINEASM node with a new one that has the zero
// register as implicit parameter.
SDValue New = DAG.getNode(N->getOpcode(), dl, N->getVTList(), Ops);
DAG.ReplaceAllUsesOfValueWith(Op, New);
DAG.ReplaceAllUsesOfValueWith(Op.getValue(1), New.getValue(1));
return New;
}
SDValue AVRTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
switch (Op.getOpcode()) {
default:
llvm_unreachable("Don't know how to custom lower this!");
case ISD::SHL:
case ISD::SRA:
case ISD::SRL:
case ISD::ROTL:
case ISD::ROTR:
return LowerShifts(Op, DAG);
case ISD::GlobalAddress:
return LowerGlobalAddress(Op, DAG);
case ISD::BlockAddress:
return LowerBlockAddress(Op, DAG);
case ISD::BR_CC:
return LowerBR_CC(Op, DAG);
case ISD::SELECT_CC:
return LowerSELECT_CC(Op, DAG);
case ISD::SETCC:
return LowerSETCC(Op, DAG);
case ISD::VASTART:
return LowerVASTART(Op, DAG);
case ISD::SDIVREM:
case ISD::UDIVREM:
return LowerDivRem(Op, DAG);
case ISD::INLINEASM:
return LowerINLINEASM(Op, DAG);
}
return SDValue();
}
/// Replace a node with an illegal result type
/// with a new node built out of custom code.
void AVRTargetLowering::ReplaceNodeResults(SDNode *N,
SmallVectorImpl<SDValue> &Results,
SelectionDAG &DAG) const {
SDLoc DL(N);
switch (N->getOpcode()) {
case ISD::ADD: {
// Convert add (x, imm) into sub (x, -imm).
if (const ConstantSDNode *C = dyn_cast<ConstantSDNode>(N->getOperand(1))) {
SDValue Sub = DAG.getNode(
ISD::SUB, DL, N->getValueType(0), N->getOperand(0),
DAG.getConstant(-C->getAPIntValue(), DL, C->getValueType(0)));
Results.push_back(Sub);
}
break;
}
default: {
SDValue Res = LowerOperation(SDValue(N, 0), DAG);
for (unsigned I = 0, E = Res->getNumValues(); I != E; ++I)
Results.push_back(Res.getValue(I));
break;
}
}
}
/// Return true if the addressing mode represented
/// by AM is legal for this target, for a load/store of the specified type.
bool AVRTargetLowering::isLegalAddressingMode(const DataLayout &DL,
const AddrMode &AM, Type *Ty,
unsigned AS,
Instruction *I) const {
int64_t Offs = AM.BaseOffs;
// Allow absolute addresses.
if (AM.BaseGV && !AM.HasBaseReg && AM.Scale == 0 && Offs == 0) {
return true;
}
// Flash memory instructions only allow zero offsets.
if (isa<PointerType>(Ty) && AS == AVR::ProgramMemory) {
return false;
}
// Allow reg+<6bit> offset.
if (Offs < 0)
Offs = -Offs;
if (AM.BaseGV == nullptr && AM.HasBaseReg && AM.Scale == 0 &&
isUInt<6>(Offs)) {
return true;
}
return false;
}
/// Returns true by value, base pointer and
/// offset pointer and addressing mode by reference if the node's address
/// can be legally represented as pre-indexed load / store address.
bool AVRTargetLowering::getPreIndexedAddressParts(SDNode *N, SDValue &Base,
SDValue &Offset,
ISD::MemIndexedMode &AM,
SelectionDAG &DAG) const {
EVT VT;
const SDNode *Op;
SDLoc DL(N);
if (const LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
VT = LD->getMemoryVT();
Op = LD->getBasePtr().getNode();
if (LD->getExtensionType() != ISD::NON_EXTLOAD)
return false;
if (AVR::isProgramMemoryAccess(LD)) {
return false;
}
} else if (const StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
VT = ST->getMemoryVT();
Op = ST->getBasePtr().getNode();
if (AVR::isProgramMemoryAccess(ST)) {
return false;
}
} else {
return false;
}
if (VT != MVT::i8 && VT != MVT::i16) {
return false;
}
if (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB) {
return false;
}
if (const ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Op->getOperand(1))) {
int RHSC = RHS->getSExtValue();
if (Op->getOpcode() == ISD::SUB)
RHSC = -RHSC;
if ((VT == MVT::i16 && RHSC != -2) || (VT == MVT::i8 && RHSC != -1)) {
return false;
}
Base = Op->getOperand(0);
Offset = DAG.getConstant(RHSC, DL, MVT::i8);
AM = ISD::PRE_DEC;
return true;
}
return false;
}
/// Returns true by value, base pointer and
/// offset pointer and addressing mode by reference if this node can be
/// combined with a load / store to form a post-indexed load / store.
bool AVRTargetLowering::getPostIndexedAddressParts(SDNode *N, SDNode *Op,
SDValue &Base,
SDValue &Offset,
ISD::MemIndexedMode &AM,
SelectionDAG &DAG) const {
EVT VT;
SDLoc DL(N);
if (const LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
VT = LD->getMemoryVT();
if (LD->getExtensionType() != ISD::NON_EXTLOAD)
return false;
} else if (const StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
VT = ST->getMemoryVT();
if (AVR::isProgramMemoryAccess(ST)) {
return false;
}
} else {
return false;
}
if (VT != MVT::i8 && VT != MVT::i16) {
return false;
}
if (Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB) {
return false;
}
if (const ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Op->getOperand(1))) {
int RHSC = RHS->getSExtValue();
if (Op->getOpcode() == ISD::SUB)
RHSC = -RHSC;
if ((VT == MVT::i16 && RHSC != 2) || (VT == MVT::i8 && RHSC != 1)) {
return false;
}
Base = Op->getOperand(0);
Offset = DAG.getConstant(RHSC, DL, MVT::i8);
AM = ISD::POST_INC;
return true;
}
return false;
}
bool AVRTargetLowering::isOffsetFoldingLegal(
const GlobalAddressSDNode *GA) const {
return true;
}
//===----------------------------------------------------------------------===//
// Formal Arguments Calling Convention Implementation
//===----------------------------------------------------------------------===//
#include "AVRGenCallingConv.inc"
/// Registers for calling conventions, ordered in reverse as required by ABI.
/// Both arrays must be of the same length.
static const MCPhysReg RegList8AVR[] = {
AVR::R25, AVR::R24, AVR::R23, AVR::R22, AVR::R21, AVR::R20,
AVR::R19, AVR::R18, AVR::R17, AVR::R16, AVR::R15, AVR::R14,
AVR::R13, AVR::R12, AVR::R11, AVR::R10, AVR::R9, AVR::R8};
static const MCPhysReg RegList8Tiny[] = {AVR::R25, AVR::R24, AVR::R23,
AVR::R22, AVR::R21, AVR::R20};
static const MCPhysReg RegList16AVR[] = {
AVR::R26R25, AVR::R25R24, AVR::R24R23, AVR::R23R22, AVR::R22R21,
AVR::R21R20, AVR::R20R19, AVR::R19R18, AVR::R18R17, AVR::R17R16,
AVR::R16R15, AVR::R15R14, AVR::R14R13, AVR::R13R12, AVR::R12R11,
AVR::R11R10, AVR::R10R9, AVR::R9R8};
static const MCPhysReg RegList16Tiny[] = {AVR::R26R25, AVR::R25R24,
AVR::R24R23, AVR::R23R22,
AVR::R22R21, AVR::R21R20};
static_assert(std::size(RegList8AVR) == std::size(RegList16AVR),
"8-bit and 16-bit register arrays must be of equal length");
static_assert(std::size(RegList8Tiny) == std::size(RegList16Tiny),
"8-bit and 16-bit register arrays must be of equal length");
/// Analyze incoming and outgoing function arguments. We need custom C++ code
/// to handle special constraints in the ABI.
/// In addition, all pieces of a certain argument have to be passed either
/// using registers or the stack but never mixing both.
template <typename ArgT>
static void analyzeArguments(TargetLowering::CallLoweringInfo *CLI,
const Function *F, const DataLayout *TD,
const SmallVectorImpl<ArgT> &Args,
SmallVectorImpl<CCValAssign> &ArgLocs,
CCState &CCInfo, bool Tiny) {
// Choose the proper register list for argument passing according to the ABI.
ArrayRef<MCPhysReg> RegList8;
ArrayRef<MCPhysReg> RegList16;
if (Tiny) {
RegList8 = ArrayRef(RegList8Tiny, std::size(RegList8Tiny));
RegList16 = ArrayRef(RegList16Tiny, std::size(RegList16Tiny));
} else {
RegList8 = ArrayRef(RegList8AVR, std::size(RegList8AVR));
RegList16 = ArrayRef(RegList16AVR, std::size(RegList16AVR));
}
unsigned NumArgs = Args.size();
// This is the index of the last used register, in RegList*.
// -1 means R26 (R26 is never actually used in CC).
int RegLastIdx = -1;
// Once a value is passed to the stack it will always be used
bool UseStack = false;
for (unsigned i = 0; i != NumArgs;) {
MVT VT = Args[i].VT;
// We have to count the number of bytes for each function argument, that is
// those Args with the same OrigArgIndex. This is important in case the
// function takes an aggregate type.
// Current argument will be between [i..j).
unsigned ArgIndex = Args[i].OrigArgIndex;
unsigned TotalBytes = VT.getStoreSize();
unsigned j = i + 1;
for (; j != NumArgs; ++j) {
if (Args[j].OrigArgIndex != ArgIndex)
break;
TotalBytes += Args[j].VT.getStoreSize();
}
// Round up to even number of bytes.
TotalBytes = alignTo(TotalBytes, 2);
// Skip zero sized arguments
if (TotalBytes == 0)
continue;
// The index of the first register to be used
unsigned RegIdx = RegLastIdx + TotalBytes;
RegLastIdx = RegIdx;
// If there are not enough registers, use the stack
if (RegIdx >= RegList8.size()) {
UseStack = true;
}
for (; i != j; ++i) {
MVT VT = Args[i].VT;
if (UseStack) {
auto evt = EVT(VT).getTypeForEVT(CCInfo.getContext());
unsigned Offset = CCInfo.AllocateStack(TD->getTypeAllocSize(evt),
TD->getABITypeAlign(evt));
CCInfo.addLoc(
CCValAssign::getMem(i, VT, Offset, VT, CCValAssign::Full));
} else {
unsigned Reg;
if (VT == MVT::i8) {
Reg = CCInfo.AllocateReg(RegList8[RegIdx]);
} else if (VT == MVT::i16) {
Reg = CCInfo.AllocateReg(RegList16[RegIdx]);
} else {
llvm_unreachable(
"calling convention can only manage i8 and i16 types");
}
assert(Reg && "register not available in calling convention");
CCInfo.addLoc(CCValAssign::getReg(i, VT, Reg, VT, CCValAssign::Full));
// Registers inside a particular argument are sorted in increasing order
// (remember the array is reversed).
RegIdx -= VT.getStoreSize();
}
}
}
}
/// Count the total number of bytes needed to pass or return these arguments.
template <typename ArgT>
static unsigned
getTotalArgumentsSizeInBytes(const SmallVectorImpl<ArgT> &Args) {
unsigned TotalBytes = 0;
for (const ArgT &Arg : Args) {
TotalBytes += Arg.VT.getStoreSize();
}
return TotalBytes;
}
/// Analyze incoming and outgoing value of returning from a function.
/// The algorithm is similar to analyzeArguments, but there can only be
/// one value, possibly an aggregate, and it is limited to 8 bytes.
template <typename ArgT>
static void analyzeReturnValues(const SmallVectorImpl<ArgT> &Args,
CCState &CCInfo, bool Tiny) {
unsigned NumArgs = Args.size();
unsigned TotalBytes = getTotalArgumentsSizeInBytes(Args);
// CanLowerReturn() guarantees this assertion.
if (Tiny)
assert(TotalBytes <= 4 &&
"return values greater than 4 bytes cannot be lowered on AVRTiny");
else
assert(TotalBytes <= 8 &&
"return values greater than 8 bytes cannot be lowered on AVR");
// Choose the proper register list for argument passing according to the ABI.
ArrayRef<MCPhysReg> RegList8;
ArrayRef<MCPhysReg> RegList16;
if (Tiny) {
RegList8 = ArrayRef(RegList8Tiny, std::size(RegList8Tiny));
RegList16 = ArrayRef(RegList16Tiny, std::size(RegList16Tiny));
} else {
RegList8 = ArrayRef(RegList8AVR, std::size(RegList8AVR));
RegList16 = ArrayRef(RegList16AVR, std::size(RegList16AVR));
}
// GCC-ABI says that the size is rounded up to the next even number,
// but actually once it is more than 4 it will always round up to 8.
if (TotalBytes > 4) {
TotalBytes = 8;
} else {
TotalBytes = alignTo(TotalBytes, 2);
}
// The index of the first register to use.
int RegIdx = TotalBytes - 1;
for (unsigned i = 0; i != NumArgs; ++i) {
MVT VT = Args[i].VT;
unsigned Reg;
if (VT == MVT::i8) {
Reg = CCInfo.AllocateReg(RegList8[RegIdx]);
} else if (VT == MVT::i16) {
Reg = CCInfo.AllocateReg(RegList16[RegIdx]);
} else {
llvm_unreachable("calling convention can only manage i8 and i16 types");
}
assert(Reg && "register not available in calling convention");
CCInfo.addLoc(CCValAssign::getReg(i, VT, Reg, VT, CCValAssign::Full));
// Registers sort in increasing order
RegIdx -= VT.getStoreSize();
}
}
SDValue AVRTargetLowering::LowerFormalArguments(
SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo &MFI = MF.getFrameInfo();
auto DL = DAG.getDataLayout();
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), ArgLocs,
*DAG.getContext());
// Variadic functions do not need all the analysis below.
if (isVarArg) {
CCInfo.AnalyzeFormalArguments(Ins, ArgCC_AVR_Vararg);
} else {
analyzeArguments(nullptr, &MF.getFunction(), &DL, Ins, ArgLocs, CCInfo,
Subtarget.hasTinyEncoding());
}
SDValue ArgValue;
for (CCValAssign &VA : ArgLocs) {
// Arguments stored on registers.
if (VA.isRegLoc()) {
EVT RegVT = VA.getLocVT();
const TargetRegisterClass *RC;
if (RegVT == MVT::i8) {
RC = &AVR::GPR8RegClass;
} else if (RegVT == MVT::i16) {
RC = &AVR::DREGSRegClass;
} else {
llvm_unreachable("Unknown argument type!");
}
Register Reg = MF.addLiveIn(VA.getLocReg(), RC);
ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, RegVT);
// :NOTE: Clang should not promote any i8 into i16 but for safety the
// following code will handle zexts or sexts generated by other
// front ends. Otherwise:
// If this is an 8 bit value, it is really passed promoted
// to 16 bits. Insert an assert[sz]ext to capture this, then
// truncate to the right size.
switch (VA.getLocInfo()) {
default:
llvm_unreachable("Unknown loc info!");
case CCValAssign::Full:
break;
case CCValAssign::BCvt:
ArgValue = DAG.getNode(ISD::BITCAST, dl, VA.getValVT(), ArgValue);
break;
case CCValAssign::SExt:
ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
break;
case CCValAssign::ZExt:
ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
break;
}
InVals.push_back(ArgValue);
} else {
// Only arguments passed on the stack should make it here.
assert(VA.isMemLoc());
EVT LocVT = VA.getLocVT();
// Create the frame index object for this incoming parameter.
int FI = MFI.CreateFixedObject(LocVT.getSizeInBits() / 8,
VA.getLocMemOffset(), true);
// Create the SelectionDAG nodes corresponding to a load
// from this parameter.
SDValue FIN = DAG.getFrameIndex(FI, getPointerTy(DL));
InVals.push_back(DAG.getLoad(LocVT, dl, Chain, FIN,
MachinePointerInfo::getFixedStack(MF, FI)));
}
}
// If the function takes variable number of arguments, make a frame index for
// the start of the first vararg value... for expansion of llvm.va_start.
if (isVarArg) {
unsigned StackSize = CCInfo.getNextStackOffset();
AVRMachineFunctionInfo *AFI = MF.getInfo<AVRMachineFunctionInfo>();
AFI->setVarArgsFrameIndex(MFI.CreateFixedObject(2, StackSize, true));
}
return Chain;
}
//===----------------------------------------------------------------------===//
// Call Calling Convention Implementation
//===----------------------------------------------------------------------===//
SDValue AVRTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
SmallVectorImpl<SDValue> &InVals) const {
SelectionDAG &DAG = CLI.DAG;
SDLoc &DL = CLI.DL;
SmallVectorImpl<ISD::OutputArg> &Outs = CLI.Outs;
SmallVectorImpl<SDValue> &OutVals = CLI.OutVals;
SmallVectorImpl<ISD::InputArg> &Ins = CLI.Ins;
SDValue Chain = CLI.Chain;
SDValue Callee = CLI.Callee;
bool &isTailCall = CLI.IsTailCall;
CallingConv::ID CallConv = CLI.CallConv;
bool isVarArg = CLI.IsVarArg;
MachineFunction &MF = DAG.getMachineFunction();
// AVR does not yet support tail call optimization.
isTailCall = false;
// Analyze operands of the call, assigning locations to each operand.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), ArgLocs,
*DAG.getContext());
// If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
// direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
// node so that legalize doesn't hack it.
const Function *F = nullptr;
if (const GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
const GlobalValue *GV = G->getGlobal();
if (isa<Function>(GV))
F = cast<Function>(GV);
Callee =
DAG.getTargetGlobalAddress(GV, DL, getPointerTy(DAG.getDataLayout()));
} else if (const ExternalSymbolSDNode *ES =
dyn_cast<ExternalSymbolSDNode>(Callee)) {
Callee = DAG.getTargetExternalSymbol(ES->getSymbol(),
getPointerTy(DAG.getDataLayout()));
}
// Variadic functions do not need all the analysis below.
if (isVarArg) {
CCInfo.AnalyzeCallOperands(Outs, ArgCC_AVR_Vararg);
} else {
analyzeArguments(&CLI, F, &DAG.getDataLayout(), Outs, ArgLocs, CCInfo,
Subtarget.hasTinyEncoding());
}
// Get a count of how many bytes are to be pushed on the stack.
unsigned NumBytes = CCInfo.getNextStackOffset();
Chain = DAG.getCALLSEQ_START(Chain, NumBytes, 0, DL);
SmallVector<std::pair<unsigned, SDValue>, 8> RegsToPass;
// First, walk the register assignments, inserting copies.
unsigned AI, AE;
bool HasStackArgs = false;
for (AI = 0, AE = ArgLocs.size(); AI != AE; ++AI) {
CCValAssign &VA = ArgLocs[AI];
EVT RegVT = VA.getLocVT();
SDValue Arg = OutVals[AI];
// Promote the value if needed. With Clang this should not happen.
switch (VA.getLocInfo()) {
default:
llvm_unreachable("Unknown loc info!");
case CCValAssign::Full:
break;
case CCValAssign::SExt:
Arg = DAG.getNode(ISD::SIGN_EXTEND, DL, RegVT, Arg);
break;
case CCValAssign::ZExt:
Arg = DAG.getNode(ISD::ZERO_EXTEND, DL, RegVT, Arg);
break;
case CCValAssign::AExt:
Arg = DAG.getNode(ISD::ANY_EXTEND, DL, RegVT, Arg);
break;
case CCValAssign::BCvt:
Arg = DAG.getNode(ISD::BITCAST, DL, RegVT, Arg);
break;
}
// Stop when we encounter a stack argument, we need to process them
// in reverse order in the loop below.
if (VA.isMemLoc()) {
HasStackArgs = true;
break;
}
// Arguments that can be passed on registers must be kept in the RegsToPass
// vector.
RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
}
// Second, stack arguments have to walked.
// Previously this code created chained stores but those chained stores appear
// to be unchained in the legalization phase. Therefore, do not attempt to
// chain them here. In fact, chaining them here somehow causes the first and
// second store to be reversed which is the exact opposite of the intended
// effect.
if (HasStackArgs) {
SmallVector<SDValue, 8> MemOpChains;
for (; AI != AE; AI++) {
CCValAssign &VA = ArgLocs[AI];
SDValue Arg = OutVals[AI];
assert(VA.isMemLoc());
// SP points to one stack slot further so add one to adjust it.
SDValue PtrOff = DAG.getNode(
ISD::ADD, DL, getPointerTy(DAG.getDataLayout()),
DAG.getRegister(AVR::SP, getPointerTy(DAG.getDataLayout())),
DAG.getIntPtrConstant(VA.getLocMemOffset() + 1, DL));
MemOpChains.push_back(
DAG.getStore(Chain, DL, Arg, PtrOff,
MachinePointerInfo::getStack(MF, VA.getLocMemOffset())));
}
if (!MemOpChains.empty())
Chain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, MemOpChains);
}
// Build a sequence of copy-to-reg nodes chained together with token chain and
// flag operands which copy the outgoing args into registers. The InFlag in
// necessary since all emited instructions must be stuck together.
SDValue InFlag;
for (auto Reg : RegsToPass) {
Chain = DAG.getCopyToReg(Chain, DL, Reg.first, Reg.second, InFlag);
InFlag = Chain.getValue(1);
}
// Returns a chain & a flag for retval copy to use.
SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
SmallVector<SDValue, 8> Ops;
Ops.push_back(Chain);
Ops.push_back(Callee);
// Add argument registers to the end of the list so that they are known live
// into the call.
for (auto Reg : RegsToPass) {
Ops.push_back(DAG.getRegister(Reg.first, Reg.second.getValueType()));
}
// The zero register (usually R1) must be passed as an implicit register so
// that this register is correctly zeroed in interrupts.
Ops.push_back(DAG.getRegister(Subtarget.getZeroRegister(), MVT::i8));
// Add a register mask operand representing the call-preserved registers.
const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
const uint32_t *Mask =
TRI->getCallPreservedMask(DAG.getMachineFunction(), CallConv);
assert(Mask && "Missing call preserved mask for calling convention");
Ops.push_back(DAG.getRegisterMask(Mask));
if (InFlag.getNode()) {
Ops.push_back(InFlag);
}
Chain = DAG.getNode(AVRISD::CALL, DL, NodeTys, Ops);
InFlag = Chain.getValue(1);
// Create the CALLSEQ_END node.
Chain = DAG.getCALLSEQ_END(Chain, NumBytes, 0, InFlag, DL);
if (!Ins.empty()) {
InFlag = Chain.getValue(1);
}
// Handle result values, copying them out of physregs into vregs that we
// return.
return LowerCallResult(Chain, InFlag, CallConv, isVarArg, Ins, DL, DAG,
InVals);
}
/// Lower the result values of a call into the
/// appropriate copies out of appropriate physical registers.
///
SDValue AVRTargetLowering::LowerCallResult(
SDValue Chain, SDValue InFlag, CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &dl,
SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
// Assign locations to each value returned by this call.
SmallVector<CCValAssign, 16> RVLocs;
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), RVLocs,
*DAG.getContext());
// Handle runtime calling convs.
if (CallConv == CallingConv::AVR_BUILTIN) {
CCInfo.AnalyzeCallResult(Ins, RetCC_AVR_BUILTIN);
} else {
analyzeReturnValues(Ins, CCInfo, Subtarget.hasTinyEncoding());
}
// Copy all of the result registers out of their specified physreg.
for (CCValAssign const &RVLoc : RVLocs) {
Chain = DAG.getCopyFromReg(Chain, dl, RVLoc.getLocReg(), RVLoc.getValVT(),
InFlag)
.getValue(1);
InFlag = Chain.getValue(2);
InVals.push_back(Chain.getValue(0));
}
return Chain;
}
//===----------------------------------------------------------------------===//
// Return Value Calling Convention Implementation
//===----------------------------------------------------------------------===//
bool AVRTargetLowering::CanLowerReturn(
CallingConv::ID CallConv, MachineFunction &MF, bool isVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs, LLVMContext &Context) const {
if (CallConv == CallingConv::AVR_BUILTIN) {
SmallVector<CCValAssign, 16> RVLocs;
CCState CCInfo(CallConv, isVarArg, MF, RVLocs, Context);
return CCInfo.CheckReturn(Outs, RetCC_AVR_BUILTIN);
}
unsigned TotalBytes = getTotalArgumentsSizeInBytes(Outs);
return TotalBytes <= (unsigned)(Subtarget.hasTinyEncoding() ? 4 : 8);
}
SDValue
AVRTargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
bool isVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals,
const SDLoc &dl, SelectionDAG &DAG) const {
// CCValAssign - represent the assignment of the return value to locations.
SmallVector<CCValAssign, 16> RVLocs;
// CCState - Info about the registers and stack slot.
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(), RVLocs,
*DAG.getContext());
MachineFunction &MF = DAG.getMachineFunction();
// Analyze return values.
if (CallConv == CallingConv::AVR_BUILTIN) {
CCInfo.AnalyzeReturn(Outs, RetCC_AVR_BUILTIN);
} else {
analyzeReturnValues(Outs, CCInfo, Subtarget.hasTinyEncoding());
}
SDValue Flag;
SmallVector<SDValue, 4> RetOps(1, Chain);
// Copy the result values into the output registers.
for (unsigned i = 0, e = RVLocs.size(); i != e; ++i) {
CCValAssign &VA = RVLocs[i];
assert(VA.isRegLoc() && "Can only return in registers!");
Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(), OutVals[i], Flag);
// Guarantee that all emitted copies are stuck together with flags.
Flag = Chain.getValue(1);
RetOps.push_back(DAG.getRegister(VA.getLocReg(), VA.getLocVT()));
}
// Don't emit the ret/reti instruction when the naked attribute is present in
// the function being compiled.
if (MF.getFunction().getAttributes().hasFnAttr(Attribute::Naked)) {
return Chain;
}
const AVRMachineFunctionInfo *AFI = MF.getInfo<AVRMachineFunctionInfo>();
if (!AFI->isInterruptOrSignalHandler()) {
// The return instruction has an implicit zero register operand: it must
// contain zero on return.
// This is not needed in interrupts however, where the zero register is
// handled specially (only pushed/popped when needed).
RetOps.push_back(DAG.getRegister(Subtarget.getZeroRegister(), MVT::i8));
}
unsigned RetOpc =
AFI->isInterruptOrSignalHandler() ? AVRISD::RETI_FLAG : AVRISD::RET_FLAG;
RetOps[0] = Chain; // Update chain.
if (Flag.getNode()) {
RetOps.push_back(Flag);
}
return DAG.getNode(RetOpc, dl, MVT::Other, RetOps);
}
//===----------------------------------------------------------------------===//
// Custom Inserters
//===----------------------------------------------------------------------===//
MachineBasicBlock *AVRTargetLowering::insertShift(MachineInstr &MI,
MachineBasicBlock *BB) const {
unsigned Opc;
const TargetRegisterClass *RC;
bool HasRepeatedOperand = false;
bool HasZeroOperand = false;
MachineFunction *F = BB->getParent();
MachineRegisterInfo &RI = F->getRegInfo();
const TargetInstrInfo &TII = *Subtarget.getInstrInfo();
DebugLoc dl = MI.getDebugLoc();
switch (MI.getOpcode()) {
default:
llvm_unreachable("Invalid shift opcode!");
case AVR::Lsl8:
Opc = AVR::ADDRdRr; // LSL is an alias of ADD Rd, Rd
RC = &AVR::GPR8RegClass;
HasRepeatedOperand = true;
break;
case AVR::Lsl16:
Opc = AVR::LSLWRd;
RC = &AVR::DREGSRegClass;
break;
case AVR::Asr8:
Opc = AVR::ASRRd;
RC = &AVR::GPR8RegClass;
break;
case AVR::Asr16:
Opc = AVR::ASRWRd;
RC = &AVR::DREGSRegClass;
break;
case AVR::Lsr8:
Opc = AVR::LSRRd;
RC = &AVR::GPR8RegClass;
break;
case AVR::Lsr16:
Opc = AVR::LSRWRd;
RC = &AVR::DREGSRegClass;
break;
case AVR::Rol8:
Opc = AVR::ROLBRd;
RC = &AVR::GPR8RegClass;
HasZeroOperand = true;
break;
case AVR::Rol16:
Opc = AVR::ROLWRd;
RC = &AVR::DREGSRegClass;
break;
case AVR::Ror8:
Opc = AVR::RORBRd;
RC = &AVR::GPR8RegClass;
break;
case AVR::Ror16:
Opc = AVR::RORWRd;
RC = &AVR::DREGSRegClass;
break;
}
const BasicBlock *LLVM_BB = BB->getBasicBlock();
MachineFunction::iterator I;
for (I = BB->getIterator(); I != F->end() && &(*I) != BB; ++I)
;
if (I != F->end())
++I;
// Create loop block.
MachineBasicBlock *LoopBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *CheckBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *RemBB = F->CreateMachineBasicBlock(LLVM_BB);
F->insert(I, LoopBB);
F->insert(I, CheckBB);
F->insert(I, RemBB);
// Update machine-CFG edges by transferring all successors of the current
// block to the block containing instructions after shift.
RemBB->splice(RemBB->begin(), BB, std::next(MachineBasicBlock::iterator(MI)),
BB->end());
RemBB->transferSuccessorsAndUpdatePHIs(BB);
// Add edges BB => LoopBB => CheckBB => RemBB, CheckBB => LoopBB.
BB->addSuccessor(CheckBB);
LoopBB->addSuccessor(CheckBB);
CheckBB->addSuccessor(LoopBB);
CheckBB->addSuccessor(RemBB);
Register ShiftAmtReg = RI.createVirtualRegister(&AVR::GPR8RegClass);
Register ShiftAmtReg2 = RI.createVirtualRegister(&AVR::GPR8RegClass);
Register ShiftReg = RI.createVirtualRegister(RC);
Register ShiftReg2 = RI.createVirtualRegister(RC);
Register ShiftAmtSrcReg = MI.getOperand(2).getReg();
Register SrcReg = MI.getOperand(1).getReg();
Register DstReg = MI.getOperand(0).getReg();
// BB:
// rjmp CheckBB
BuildMI(BB, dl, TII.get(AVR::RJMPk)).addMBB(CheckBB);
// LoopBB:
// ShiftReg2 = shift ShiftReg
auto ShiftMI = BuildMI(LoopBB, dl, TII.get(Opc), ShiftReg2).addReg(ShiftReg);
if (HasRepeatedOperand)
ShiftMI.addReg(ShiftReg);
if (HasZeroOperand)
ShiftMI.addReg(Subtarget.getZeroRegister());
// CheckBB:
// ShiftReg = phi [%SrcReg, BB], [%ShiftReg2, LoopBB]
// ShiftAmt = phi [%N, BB], [%ShiftAmt2, LoopBB]
// DestReg = phi [%SrcReg, BB], [%ShiftReg, LoopBB]
// ShiftAmt2 = ShiftAmt - 1;
// if (ShiftAmt2 >= 0) goto LoopBB;
BuildMI(CheckBB, dl, TII.get(AVR::PHI), ShiftReg)
.addReg(SrcReg)
.addMBB(BB)
.addReg(ShiftReg2)
.addMBB(LoopBB);
BuildMI(CheckBB, dl, TII.get(AVR::PHI), ShiftAmtReg)
.addReg(ShiftAmtSrcReg)
.addMBB(BB)
.addReg(ShiftAmtReg2)
.addMBB(LoopBB);
BuildMI(CheckBB, dl, TII.get(AVR::PHI), DstReg)
.addReg(SrcReg)
.addMBB(BB)
.addReg(ShiftReg2)
.addMBB(LoopBB);
BuildMI(CheckBB, dl, TII.get(AVR::DECRd), ShiftAmtReg2).addReg(ShiftAmtReg);
BuildMI(CheckBB, dl, TII.get(AVR::BRPLk)).addMBB(LoopBB);
MI.eraseFromParent(); // The pseudo instruction is gone now.
return RemBB;
}
// Do a multibyte AVR shift. Insert shift instructions and put the output
// registers in the Regs array.
// Because AVR does not have a normal shift instruction (only a single bit shift
// instruction), we have to emulate this behavior with other instructions.
// It first tries large steps (moving registers around) and then smaller steps
// like single bit shifts.
// Large shifts actually reduce the number of shifted registers, so the below
// algorithms have to work independently of the number of registers that are
// shifted.
// For more information and background, see this blogpost:
// https://aykevl.nl/2021/02/avr-bitshift
static void insertMultibyteShift(MachineInstr &MI, MachineBasicBlock *BB,
MutableArrayRef<std::pair<Register, int>> Regs,
ISD::NodeType Opc, int64_t ShiftAmt) {
const TargetInstrInfo &TII = *BB->getParent()->getSubtarget().getInstrInfo();
const AVRSubtarget &STI = BB->getParent()->getSubtarget<AVRSubtarget>();
MachineRegisterInfo &MRI = BB->getParent()->getRegInfo();
const DebugLoc &dl = MI.getDebugLoc();
const bool ShiftLeft = Opc == ISD::SHL;
const bool ArithmeticShift = Opc == ISD::SRA;
// Zero a register, for use in later operations.
Register ZeroReg = MRI.createVirtualRegister(&AVR::GPR8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::COPY), ZeroReg)
.addReg(STI.getZeroRegister());
// Do a shift modulo 6 or 7. This is a bit more complicated than most shifts
// and is hard to compose with the rest, so these are special cased.
// The basic idea is to shift one or two bits in the opposite direction and
// then move registers around to get the correct end result.
if (ShiftLeft && (ShiftAmt % 8) >= 6) {
// Left shift modulo 6 or 7.
// Create a slice of the registers we're going to modify, to ease working
// with them.
size_t ShiftRegsOffset = ShiftAmt / 8;
size_t ShiftRegsSize = Regs.size() - ShiftRegsOffset;
MutableArrayRef<std::pair<Register, int>> ShiftRegs =
Regs.slice(ShiftRegsOffset, ShiftRegsSize);
// Shift one to the right, keeping the least significant bit as the carry
// bit.
insertMultibyteShift(MI, BB, ShiftRegs, ISD::SRL, 1);
// Rotate the least significant bit from the carry bit into a new register
// (that starts out zero).
Register LowByte = MRI.createVirtualRegister(&AVR::GPR8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::RORRd), LowByte).addReg(ZeroReg);
// Shift one more to the right if this is a modulo-6 shift.
if (ShiftAmt % 8 == 6) {
insertMultibyteShift(MI, BB, ShiftRegs, ISD::SRL, 1);
Register NewLowByte = MRI.createVirtualRegister(&AVR::GPR8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::RORRd), NewLowByte).addReg(LowByte);
LowByte = NewLowByte;
}
// Move all registers to the left, zeroing the bottom registers as needed.
for (size_t I = 0; I < Regs.size(); I++) {
int ShiftRegsIdx = I + 1;
if (ShiftRegsIdx < (int)ShiftRegs.size()) {
Regs[I] = ShiftRegs[ShiftRegsIdx];
} else if (ShiftRegsIdx == (int)ShiftRegs.size()) {
Regs[I] = std::pair(LowByte, 0);
} else {
Regs[I] = std::pair(ZeroReg, 0);
}
}
return;
}
// Right shift modulo 6 or 7.
if (!ShiftLeft && (ShiftAmt % 8) >= 6) {
// Create a view on the registers we're going to modify, to ease working
// with them.
size_t ShiftRegsSize = Regs.size() - (ShiftAmt / 8);
MutableArrayRef<std::pair<Register, int>> ShiftRegs =
Regs.slice(0, ShiftRegsSize);
// Shift one to the left.
insertMultibyteShift(MI, BB, ShiftRegs, ISD::SHL, 1);
// Sign or zero extend the most significant register into a new register.
// The HighByte is the byte that still has one (or two) bits from the
// original value. The ExtByte is purely a zero/sign extend byte (all bits
// are either 0 or 1).
Register HighByte = MRI.createVirtualRegister(&AVR::GPR8RegClass);
Register ExtByte = 0;
if (ArithmeticShift) {
// Sign-extend bit that was shifted out last.
BuildMI(*BB, MI, dl, TII.get(AVR::SBCRdRr), HighByte)
.addReg(HighByte, RegState::Undef)
.addReg(HighByte, RegState::Undef);
ExtByte = HighByte;
// The highest bit of the original value is the same as the zero-extend
// byte, so HighByte and ExtByte are the same.
} else {
// Use the zero register for zero extending.
ExtByte = ZeroReg;
// Rotate most significant bit into a new register (that starts out zero).
BuildMI(*BB, MI, dl, TII.get(AVR::ADCRdRr), HighByte)
.addReg(ExtByte)
.addReg(ExtByte);
}
// Shift one more to the left for modulo 6 shifts.
if (ShiftAmt % 8 == 6) {
insertMultibyteShift(MI, BB, ShiftRegs, ISD::SHL, 1);
// Shift the topmost bit into the HighByte.
Register NewExt = MRI.createVirtualRegister(&AVR::GPR8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::ADCRdRr), NewExt)
.addReg(HighByte)
.addReg(HighByte);
HighByte = NewExt;
}
// Move all to the right, while sign or zero extending.
for (int I = Regs.size() - 1; I >= 0; I--) {
int ShiftRegsIdx = I - (Regs.size() - ShiftRegs.size()) - 1;
if (ShiftRegsIdx >= 0) {
Regs[I] = ShiftRegs[ShiftRegsIdx];
} else if (ShiftRegsIdx == -1) {
Regs[I] = std::pair(HighByte, 0);
} else {
Regs[I] = std::pair(ExtByte, 0);
}
}
return;
}
// For shift amounts of at least one register, simply rename the registers and
// zero the bottom registers.
while (ShiftLeft && ShiftAmt >= 8) {
// Move all registers one to the left.
for (size_t I = 0; I < Regs.size() - 1; I++) {
Regs[I] = Regs[I + 1];
}
// Zero the least significant register.
Regs[Regs.size() - 1] = std::pair(ZeroReg, 0);
// Continue shifts with the leftover registers.
Regs = Regs.drop_back(1);
ShiftAmt -= 8;
}
// And again, the same for right shifts.
Register ShrExtendReg = 0;
if (!ShiftLeft && ShiftAmt >= 8) {
if (ArithmeticShift) {
// Sign extend the most significant register into ShrExtendReg.
ShrExtendReg = MRI.createVirtualRegister(&AVR::GPR8RegClass);
Register Tmp = MRI.createVirtualRegister(&AVR::GPR8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::ADDRdRr), Tmp)
.addReg(Regs[0].first, 0, Regs[0].second)
.addReg(Regs[0].first, 0, Regs[0].second);
BuildMI(*BB, MI, dl, TII.get(AVR::SBCRdRr), ShrExtendReg)
.addReg(Tmp)
.addReg(Tmp);
} else {
ShrExtendReg = ZeroReg;
}
for (; ShiftAmt >= 8; ShiftAmt -= 8) {
// Move all registers one to the right.
for (size_t I = Regs.size() - 1; I != 0; I--) {
Regs[I] = Regs[I - 1];
}
// Zero or sign extend the most significant register.
Regs[0] = std::pair(ShrExtendReg, 0);
// Continue shifts with the leftover registers.
Regs = Regs.drop_front(1);
}
}
// The bigger shifts are already handled above.
assert((ShiftAmt < 8) && "Unexpect shift amount");
// Shift by four bits, using a complicated swap/eor/andi/eor sequence.
// It only works for logical shifts because the bits shifted in are all
// zeroes.
// To shift a single byte right, it produces code like this:
// swap r0
// andi r0, 0x0f
// For a two-byte (16-bit) shift, it adds the following instructions to shift
// the upper byte into the lower byte:
// swap r1
// eor r0, r1
// andi r1, 0x0f
// eor r0, r1
// For bigger shifts, it repeats the above sequence. For example, for a 3-byte
// (24-bit) shift it adds:
// swap r2
// eor r1, r2
// andi r2, 0x0f
// eor r1, r2
if (!ArithmeticShift && ShiftAmt >= 4) {
Register Prev = 0;
for (size_t I = 0; I < Regs.size(); I++) {
size_t Idx = ShiftLeft ? I : Regs.size() - I - 1;
Register SwapReg = MRI.createVirtualRegister(&AVR::LD8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::SWAPRd), SwapReg)
.addReg(Regs[Idx].first, 0, Regs[Idx].second);
if (I != 0) {
Register R = MRI.createVirtualRegister(&AVR::GPR8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::EORRdRr), R)
.addReg(Prev)
.addReg(SwapReg);
Prev = R;
}
Register AndReg = MRI.createVirtualRegister(&AVR::LD8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::ANDIRdK), AndReg)
.addReg(SwapReg)
.addImm(ShiftLeft ? 0xf0 : 0x0f);
if (I != 0) {
Register R = MRI.createVirtualRegister(&AVR::GPR8RegClass);
BuildMI(*BB, MI, dl, TII.get(AVR::EORRdRr), R)
.addReg(Prev)
.addReg(AndReg);
size_t PrevIdx = ShiftLeft ? Idx - 1 : Idx + 1;
Regs[PrevIdx] = std::pair(R, 0);
}
Prev = AndReg;
Regs[Idx] = std::pair(AndReg, 0);
}
ShiftAmt -= 4;
}
// Shift by one. This is the fallback that always works, and the shift
// operation that is used for 1, 2, and 3 bit shifts.
while (ShiftLeft && ShiftAmt) {
// Shift one to the left.
for (ssize_t I = Regs.size() - 1; I >= 0; I--) {
Register Out = MRI.createVirtualRegister(&AVR::GPR8RegClass);
Register In = Regs[I].first;
Register InSubreg = Regs[I].second;
if (I == (ssize_t)Regs.size() - 1) { // first iteration
BuildMI(*BB, MI, dl, TII.get(AVR::ADDRdRr), Out)
.addReg(In, 0, InSubreg)
.addReg(In, 0, InSubreg);
} else {
BuildMI(*BB, MI, dl, TII.get(AVR::ADCRdRr), Out)
.addReg(In, 0, InSubreg)
.addReg(In, 0, InSubreg);
}
Regs[I] = std::pair(Out, 0);
}
ShiftAmt--;
}
while (!ShiftLeft && ShiftAmt) {
// Shift one to the right.
for (size_t I = 0; I < Regs.size(); I++) {
Register Out = MRI.createVirtualRegister(&AVR::GPR8RegClass);
Register In = Regs[I].first;
Register InSubreg = Regs[I].second;
if (I == 0) {
unsigned Opc = ArithmeticShift ? AVR::ASRRd : AVR::LSRRd;
BuildMI(*BB, MI, dl, TII.get(Opc), Out).addReg(In, 0, InSubreg);
} else {
BuildMI(*BB, MI, dl, TII.get(AVR::RORRd), Out).addReg(In, 0, InSubreg);
}
Regs[I] = std::pair(Out, 0);
}
ShiftAmt--;
}
if (ShiftAmt != 0) {
llvm_unreachable("don't know how to shift!"); // sanity check
}
}
// Do a wide (32-bit) shift.
MachineBasicBlock *
AVRTargetLowering::insertWideShift(MachineInstr &MI,
MachineBasicBlock *BB) const {
const TargetInstrInfo &TII = *Subtarget.getInstrInfo();
const DebugLoc &dl = MI.getDebugLoc();
// How much to shift to the right (meaning: a negative number indicates a left
// shift).
int64_t ShiftAmt = MI.getOperand(4).getImm();
ISD::NodeType Opc;
switch (MI.getOpcode()) {
case AVR::Lsl32:
Opc = ISD::SHL;
break;
case AVR::Lsr32:
Opc = ISD::SRL;
break;
case AVR::Asr32:
Opc = ISD::SRA;
break;
}
// Read the input registers, with the most significant register at index 0.
std::array<std::pair<Register, int>, 4> Registers = {
std::pair(MI.getOperand(3).getReg(), AVR::sub_hi),
std::pair(MI.getOperand(3).getReg(), AVR::sub_lo),
std::pair(MI.getOperand(2).getReg(), AVR::sub_hi),
std::pair(MI.getOperand(2).getReg(), AVR::sub_lo),
};
// Do the shift. The registers are modified in-place.
insertMultibyteShift(MI, BB, Registers, Opc, ShiftAmt);
// Combine the 8-bit registers into 16-bit register pairs.
// This done either from LSB to MSB or from MSB to LSB, depending on the
// shift. It's an optimization so that the register allocator will use the
// fewest movs possible (which order we use isn't a correctness issue, just an
// optimization issue).
// - lsl prefers starting from the most significant byte (2nd case).
// - lshr prefers starting from the least significant byte (1st case).
// - for ashr it depends on the number of shifted bytes.
// Some shift operations still don't get the most optimal mov sequences even
// with this distinction. TODO: figure out why and try to fix it (but we're
// already equal to or faster than avr-gcc in all cases except ashr 8).
if (Opc != ISD::SHL &&
(Opc != ISD::SRA || (ShiftAmt < 16 || ShiftAmt >= 22))) {
// Use the resulting registers starting with the least significant byte.
BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(0).getReg())
.addReg(Registers[3].first, 0, Registers[3].second)
.addImm(AVR::sub_lo)
.addReg(Registers[2].first, 0, Registers[2].second)
.addImm(AVR::sub_hi);
BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(1).getReg())
.addReg(Registers[1].first, 0, Registers[1].second)
.addImm(AVR::sub_lo)
.addReg(Registers[0].first, 0, Registers[0].second)
.addImm(AVR::sub_hi);
} else {
// Use the resulting registers starting with the most significant byte.
BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(1).getReg())
.addReg(Registers[0].first, 0, Registers[0].second)
.addImm(AVR::sub_hi)
.addReg(Registers[1].first, 0, Registers[1].second)
.addImm(AVR::sub_lo);
BuildMI(*BB, MI, dl, TII.get(AVR::REG_SEQUENCE), MI.getOperand(0).getReg())
.addReg(Registers[2].first, 0, Registers[2].second)
.addImm(AVR::sub_hi)
.addReg(Registers[3].first, 0, Registers[3].second)
.addImm(AVR::sub_lo);
}
// Remove the pseudo instruction.
MI.eraseFromParent();
return BB;
}
static bool isCopyMulResult(MachineBasicBlock::iterator const &I) {
if (I->getOpcode() == AVR::COPY) {
Register SrcReg = I->getOperand(1).getReg();
return (SrcReg == AVR::R0 || SrcReg == AVR::R1);
}
return false;
}
// The mul instructions wreak havock on our zero_reg R1. We need to clear it
// after the result has been evacuated. This is probably not the best way to do
// it, but it works for now.
MachineBasicBlock *AVRTargetLowering::insertMul(MachineInstr &MI,
MachineBasicBlock *BB) const {
const TargetInstrInfo &TII = *Subtarget.getInstrInfo();
MachineBasicBlock::iterator I(MI);
++I; // in any case insert *after* the mul instruction
if (isCopyMulResult(I))
++I;
if (isCopyMulResult(I))
++I;
BuildMI(*BB, I, MI.getDebugLoc(), TII.get(AVR::EORRdRr), AVR::R1)
.addReg(AVR::R1)
.addReg(AVR::R1);
return BB;
}
// Insert a read from the zero register.
MachineBasicBlock *
AVRTargetLowering::insertCopyZero(MachineInstr &MI,
MachineBasicBlock *BB) const {
const TargetInstrInfo &TII = *Subtarget.getInstrInfo();
MachineBasicBlock::iterator I(MI);
BuildMI(*BB, I, MI.getDebugLoc(), TII.get(AVR::COPY))
.add(MI.getOperand(0))
.addReg(Subtarget.getZeroRegister());
MI.eraseFromParent();
return BB;
}
// Lower atomicrmw operation to disable interrupts, do operation, and restore
// interrupts. This works because all AVR microcontrollers are single core.
MachineBasicBlock *AVRTargetLowering::insertAtomicArithmeticOp(
MachineInstr &MI, MachineBasicBlock *BB, unsigned Opcode, int Width) const {
MachineRegisterInfo &MRI = BB->getParent()->getRegInfo();
const TargetInstrInfo &TII = *Subtarget.getInstrInfo();
MachineBasicBlock::iterator I(MI);
DebugLoc dl = MI.getDebugLoc();
// Example instruction sequence, for an atomic 8-bit add:
// ldi r25, 5
// in r0, SREG
// cli
// ld r24, X
// add r25, r24
// st X, r25
// out SREG, r0
const TargetRegisterClass *RC =
(Width == 8) ? &AVR::GPR8RegClass : &AVR::DREGSRegClass;
unsigned LoadOpcode = (Width == 8) ? AVR::LDRdPtr : AVR::LDWRdPtr;
unsigned StoreOpcode = (Width == 8) ? AVR::STPtrRr : AVR::STWPtrRr;
// Disable interrupts.
BuildMI(*BB, I, dl, TII.get(AVR::INRdA), Subtarget.getTmpRegister())
.addImm(Subtarget.getIORegSREG());
BuildMI(*BB, I, dl, TII.get(AVR::BCLRs)).addImm(7);
// Load the original value.
BuildMI(*BB, I, dl, TII.get(LoadOpcode), MI.getOperand(0).getReg())
.add(MI.getOperand(1));
// Do the arithmetic operation.
Register Result = MRI.createVirtualRegister(RC);
BuildMI(*BB, I, dl, TII.get(Opcode), Result)
.addReg(MI.getOperand(0).getReg())
.add(MI.getOperand(2));
// Store the result.
BuildMI(*BB, I, dl, TII.get(StoreOpcode))
.add(MI.getOperand(1))
.addReg(Result);
// Restore interrupts.
BuildMI(*BB, I, dl, TII.get(AVR::OUTARr))
.addImm(Subtarget.getIORegSREG())
.addReg(Subtarget.getTmpRegister());
// Remove the pseudo instruction.
MI.eraseFromParent();
return BB;
}
MachineBasicBlock *
AVRTargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
MachineBasicBlock *MBB) const {
int Opc = MI.getOpcode();
// Pseudo shift instructions with a non constant shift amount are expanded
// into a loop.
switch (Opc) {
case AVR::Lsl8:
case AVR::Lsl16:
case AVR::Lsr8:
case AVR::Lsr16:
case AVR::Rol8:
case AVR::Rol16:
case AVR::Ror8:
case AVR::Ror16:
case AVR::Asr8:
case AVR::Asr16:
return insertShift(MI, MBB);
case AVR::Lsl32:
case AVR::Lsr32:
case AVR::Asr32:
return insertWideShift(MI, MBB);
case AVR::MULRdRr:
case AVR::MULSRdRr:
return insertMul(MI, MBB);
case AVR::CopyZero:
return insertCopyZero(MI, MBB);
case AVR::AtomicLoadAdd8:
return insertAtomicArithmeticOp(MI, MBB, AVR::ADDRdRr, 8);
case AVR::AtomicLoadAdd16:
return insertAtomicArithmeticOp(MI, MBB, AVR::ADDWRdRr, 16);
case AVR::AtomicLoadSub8:
return insertAtomicArithmeticOp(MI, MBB, AVR::SUBRdRr, 8);
case AVR::AtomicLoadSub16:
return insertAtomicArithmeticOp(MI, MBB, AVR::SUBWRdRr, 16);
case AVR::AtomicLoadAnd8:
return insertAtomicArithmeticOp(MI, MBB, AVR::ANDRdRr, 8);
case AVR::AtomicLoadAnd16:
return insertAtomicArithmeticOp(MI, MBB, AVR::ANDWRdRr, 16);
case AVR::AtomicLoadOr8:
return insertAtomicArithmeticOp(MI, MBB, AVR::ORRdRr, 8);
case AVR::AtomicLoadOr16:
return insertAtomicArithmeticOp(MI, MBB, AVR::ORWRdRr, 16);
case AVR::AtomicLoadXor8:
return insertAtomicArithmeticOp(MI, MBB, AVR::EORRdRr, 8);
case AVR::AtomicLoadXor16:
return insertAtomicArithmeticOp(MI, MBB, AVR::EORWRdRr, 16);
}
assert((Opc == AVR::Select16 || Opc == AVR::Select8) &&
"Unexpected instr type to insert");
const AVRInstrInfo &TII = (const AVRInstrInfo &)*MI.getParent()
->getParent()
->getSubtarget()
.getInstrInfo();
DebugLoc dl = MI.getDebugLoc();
// To "insert" a SELECT instruction, we insert the diamond
// control-flow pattern. The incoming instruction knows the
// destination vreg to set, the condition code register to branch
// on, the true/false values to select between, and a branch opcode
// to use.
MachineFunction *MF = MBB->getParent();
const BasicBlock *LLVM_BB = MBB->getBasicBlock();
MachineBasicBlock *FallThrough = MBB->getFallThrough();
// If the current basic block falls through to another basic block,
// we must insert an unconditional branch to the fallthrough destination
// if we are to insert basic blocks at the prior fallthrough point.
if (FallThrough != nullptr) {
BuildMI(MBB, dl, TII.get(AVR::RJMPk)).addMBB(FallThrough);
}
MachineBasicBlock *trueMBB = MF->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *falseMBB = MF->CreateMachineBasicBlock(LLVM_BB);
MachineFunction::iterator I;
for (I = MF->begin(); I != MF->end() && &(*I) != MBB; ++I)
;
if (I != MF->end())
++I;
MF->insert(I, trueMBB);
MF->insert(I, falseMBB);
// Transfer remaining instructions and all successors of the current
// block to the block which will contain the Phi node for the
// select.
trueMBB->splice(trueMBB->begin(), MBB,
std::next(MachineBasicBlock::iterator(MI)), MBB->end());
trueMBB->transferSuccessorsAndUpdatePHIs(MBB);
AVRCC::CondCodes CC = (AVRCC::CondCodes)MI.getOperand(3).getImm();
BuildMI(MBB, dl, TII.getBrCond(CC)).addMBB(trueMBB);
BuildMI(MBB, dl, TII.get(AVR::RJMPk)).addMBB(falseMBB);
MBB->addSuccessor(falseMBB);
MBB->addSuccessor(trueMBB);
// Unconditionally flow back to the true block
BuildMI(falseMBB, dl, TII.get(AVR::RJMPk)).addMBB(trueMBB);
falseMBB->addSuccessor(trueMBB);
// Set up the Phi node to determine where we came from
BuildMI(*trueMBB, trueMBB->begin(), dl, TII.get(AVR::PHI),
MI.getOperand(0).getReg())
.addReg(MI.getOperand(1).getReg())
.addMBB(MBB)
.addReg(MI.getOperand(2).getReg())
.addMBB(falseMBB);
MI.eraseFromParent(); // The pseudo instruction is gone now.
return trueMBB;
}
//===----------------------------------------------------------------------===//
// Inline Asm Support
//===----------------------------------------------------------------------===//
AVRTargetLowering::ConstraintType
AVRTargetLowering::getConstraintType(StringRef Constraint) const {
if (Constraint.size() == 1) {
// See http://www.nongnu.org/avr-libc/user-manual/inline_asm.html
switch (Constraint[0]) {
default:
break;
case 'a': // Simple upper registers
case 'b': // Base pointer registers pairs
case 'd': // Upper register
case 'l': // Lower registers
case 'e': // Pointer register pairs
case 'q': // Stack pointer register
case 'r': // Any register
case 'w': // Special upper register pairs
return C_RegisterClass;
case 't': // Temporary register
case 'x':
case 'X': // Pointer register pair X
case 'y':
case 'Y': // Pointer register pair Y
case 'z':
case 'Z': // Pointer register pair Z
return C_Register;
case 'Q': // A memory address based on Y or Z pointer with displacement.
return C_Memory;
case 'G': // Floating point constant
case 'I': // 6-bit positive integer constant
case 'J': // 6-bit negative integer constant
case 'K': // Integer constant (Range: 2)
case 'L': // Integer constant (Range: 0)
case 'M': // 8-bit integer constant
case 'N': // Integer constant (Range: -1)
case 'O': // Integer constant (Range: 8, 16, 24)
case 'P': // Integer constant (Range: 1)
case 'R': // Integer constant (Range: -6 to 5)x
return C_Immediate;
}
}
return TargetLowering::getConstraintType(Constraint);
}
unsigned
AVRTargetLowering::getInlineAsmMemConstraint(StringRef ConstraintCode) const {
// Not sure if this is actually the right thing to do, but we got to do
// *something* [agnat]
switch (ConstraintCode[0]) {
case 'Q':
return InlineAsm::Constraint_Q;
}
return TargetLowering::getInlineAsmMemConstraint(ConstraintCode);
}
AVRTargetLowering::ConstraintWeight
AVRTargetLowering::getSingleConstraintMatchWeight(
AsmOperandInfo &info, const char *constraint) const {
ConstraintWeight weight = CW_Invalid;
Value *CallOperandVal = info.CallOperandVal;
// If we don't have a value, we can't do a match,
// but allow it at the lowest weight.
// (this behaviour has been copied from the ARM backend)
if (!CallOperandVal) {
return CW_Default;
}
// Look at the constraint type.
switch (*constraint) {
default:
weight = TargetLowering::getSingleConstraintMatchWeight(info, constraint);
break;
case 'd':
case 'r':
case 'l':
weight = CW_Register;
break;
case 'a':
case 'b':
case 'e':
case 'q':
case 't':
case 'w':
case 'x':
case 'X':
case 'y':
case 'Y':
case 'z':
case 'Z':
weight = CW_SpecificReg;
break;
case 'G':
if (const ConstantFP *C = dyn_cast<ConstantFP>(CallOperandVal)) {
if (C->isZero()) {
weight = CW_Constant;
}
}
break;
case 'I':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if (isUInt<6>(C->getZExtValue())) {
weight = CW_Constant;
}
}
break;
case 'J':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if ((C->getSExtValue() >= -63) && (C->getSExtValue() <= 0)) {
weight = CW_Constant;
}
}
break;
case 'K':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if (C->getZExtValue() == 2) {
weight = CW_Constant;
}
}
break;
case 'L':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if (C->getZExtValue() == 0) {
weight = CW_Constant;
}
}
break;
case 'M':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if (isUInt<8>(C->getZExtValue())) {
weight = CW_Constant;
}
}
break;
case 'N':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if (C->getSExtValue() == -1) {
weight = CW_Constant;
}
}
break;
case 'O':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if ((C->getZExtValue() == 8) || (C->getZExtValue() == 16) ||
(C->getZExtValue() == 24)) {
weight = CW_Constant;
}
}
break;
case 'P':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if (C->getZExtValue() == 1) {
weight = CW_Constant;
}
}
break;
case 'R':
if (const ConstantInt *C = dyn_cast<ConstantInt>(CallOperandVal)) {
if ((C->getSExtValue() >= -6) && (C->getSExtValue() <= 5)) {
weight = CW_Constant;
}
}
break;
case 'Q':
weight = CW_Memory;
break;
}
return weight;
}
std::pair<unsigned, const TargetRegisterClass *>
AVRTargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
StringRef Constraint,
MVT VT) const {
if (Constraint.size() == 1) {
switch (Constraint[0]) {
case 'a': // Simple upper registers r16..r23.
if (VT == MVT::i8)
return std::make_pair(0U, &AVR::LD8loRegClass);
else if (VT == MVT::i16)
return std::make_pair(0U, &AVR::DREGSLD8loRegClass);
break;
case 'b': // Base pointer registers: y, z.
if (VT == MVT::i8 || VT == MVT::i16)
return std::make_pair(0U, &AVR::PTRDISPREGSRegClass);
break;
case 'd': // Upper registers r16..r31.
if (VT == MVT::i8)
return std::make_pair(0U, &AVR::LD8RegClass);
else if (VT == MVT::i16)
return std::make_pair(0U, &AVR::DLDREGSRegClass);
break;
case 'l': // Lower registers r0..r15.
if (VT == MVT::i8)
return std::make_pair(0U, &AVR::GPR8loRegClass);
else if (VT == MVT::i16)
return std::make_pair(0U, &AVR::DREGSloRegClass);
break;
case 'e': // Pointer register pairs: x, y, z.
if (VT == MVT::i8 || VT == MVT::i16)
return std::make_pair(0U, &AVR::PTRREGSRegClass);
break;
case 'q': // Stack pointer register: SPH:SPL.
return std::make_pair(0U, &AVR::GPRSPRegClass);
case 'r': // Any register: r0..r31.
if (VT == MVT::i8)
return std::make_pair(0U, &AVR::GPR8RegClass);
else if (VT == MVT::i16)
return std::make_pair(0U, &AVR::DREGSRegClass);
break;
case 't': // Temporary register: r0.
if (VT == MVT::i8)
return std::make_pair(unsigned(Subtarget.getTmpRegister()),
&AVR::GPR8RegClass);
break;
case 'w': // Special upper register pairs: r24, r26, r28, r30.
if (VT == MVT::i8 || VT == MVT::i16)
return std::make_pair(0U, &AVR::IWREGSRegClass);
break;
case 'x': // Pointer register pair X: r27:r26.
case 'X':
if (VT == MVT::i8 || VT == MVT::i16)
return std::make_pair(unsigned(AVR::R27R26), &AVR::PTRREGSRegClass);
break;
case 'y': // Pointer register pair Y: r29:r28.
case 'Y':
if (VT == MVT::i8 || VT == MVT::i16)
return std::make_pair(unsigned(AVR::R29R28), &AVR::PTRREGSRegClass);
break;
case 'z': // Pointer register pair Z: r31:r30.
case 'Z':
if (VT == MVT::i8 || VT == MVT::i16)
return std::make_pair(unsigned(AVR::R31R30), &AVR::PTRREGSRegClass);
break;
default:
break;
}
}
return TargetLowering::getRegForInlineAsmConstraint(
Subtarget.getRegisterInfo(), Constraint, VT);
}
void AVRTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
std::string &Constraint,
std::vector<SDValue> &Ops,
SelectionDAG &DAG) const {
SDValue Result;
SDLoc DL(Op);
EVT Ty = Op.getValueType();
// Currently only support length 1 constraints.
if (Constraint.length() != 1) {
return;
}
char ConstraintLetter = Constraint[0];
switch (ConstraintLetter) {
default:
break;
// Deal with integers first:
case 'I':
case 'J':
case 'K':
case 'L':
case 'M':
case 'N':
case 'O':
case 'P':
case 'R': {
const ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op);
if (!C) {
return;
}
int64_t CVal64 = C->getSExtValue();
uint64_t CUVal64 = C->getZExtValue();
switch (ConstraintLetter) {
case 'I': // 0..63
if (!isUInt<6>(CUVal64))
return;
Result = DAG.getTargetConstant(CUVal64, DL, Ty);
break;
case 'J': // -63..0
if (CVal64 < -63 || CVal64 > 0)
return;
Result = DAG.getTargetConstant(CVal64, DL, Ty);
break;
case 'K': // 2
if (CUVal64 != 2)
return;
Result = DAG.getTargetConstant(CUVal64, DL, Ty);
break;
case 'L': // 0
if (CUVal64 != 0)
return;
Result = DAG.getTargetConstant(CUVal64, DL, Ty);
break;
case 'M': // 0..255
if (!isUInt<8>(CUVal64))
return;
// i8 type may be printed as a negative number,
// e.g. 254 would be printed as -2,
// so we force it to i16 at least.
if (Ty.getSimpleVT() == MVT::i8) {
Ty = MVT::i16;
}
Result = DAG.getTargetConstant(CUVal64, DL, Ty);
break;
case 'N': // -1
if (CVal64 != -1)
return;
Result = DAG.getTargetConstant(CVal64, DL, Ty);
break;
case 'O': // 8, 16, 24
if (CUVal64 != 8 && CUVal64 != 16 && CUVal64 != 24)
return;
Result = DAG.getTargetConstant(CUVal64, DL, Ty);
break;
case 'P': // 1
if (CUVal64 != 1)
return;
Result = DAG.getTargetConstant(CUVal64, DL, Ty);
break;
case 'R': // -6..5
if (CVal64 < -6 || CVal64 > 5)
return;
Result = DAG.getTargetConstant(CVal64, DL, Ty);
break;
}
break;
}
case 'G':
const ConstantFPSDNode *FC = dyn_cast<ConstantFPSDNode>(Op);
if (!FC || !FC->isZero())
return;
// Soften float to i8 0
Result = DAG.getTargetConstant(0, DL, MVT::i8);
break;
}
if (Result.getNode()) {
Ops.push_back(Result);
return;
}
return TargetLowering::LowerAsmOperandForConstraint(Op, Constraint, Ops, DAG);
}
Register AVRTargetLowering::getRegisterByName(const char *RegName, LLT VT,
const MachineFunction &MF) const {
Register Reg;
if (VT == LLT::scalar(8)) {
Reg = StringSwitch<unsigned>(RegName)
.Case("r0", AVR::R0)
.Case("r1", AVR::R1)
.Default(0);
} else {
Reg = StringSwitch<unsigned>(RegName)
.Case("r0", AVR::R1R0)
.Case("sp", AVR::SP)
.Default(0);
}
if (Reg)
return Reg;
report_fatal_error(
Twine("Invalid register name \"" + StringRef(RegName) + "\"."));
}
} // end of namespace llvm