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llvm-for-llvmta/lib/Target/Lanai/LanaiISelLowering.cpp

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//===-- LanaiISelLowering.cpp - Lanai 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 implements the LanaiTargetLowering class.
//
//===----------------------------------------------------------------------===//
#include "LanaiISelLowering.h"
#include "Lanai.h"
#include "LanaiCondCode.h"
#include "LanaiMachineFunctionInfo.h"
#include "LanaiSubtarget.h"
#include "LanaiTargetObjectFile.h"
#include "MCTargetDesc/LanaiBaseInfo.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RuntimeLibcalls.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/TargetCallingConv.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MachineValueType.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdlib>
#include <utility>
#define DEBUG_TYPE "lanai-lower"
using namespace llvm;
// Limit on number of instructions the lowered multiplication may have before a
// call to the library function should be generated instead. The threshold is
// currently set to 14 as this was the smallest threshold that resulted in all
// constant multiplications being lowered. A threshold of 5 covered all cases
// except for one multiplication which required 14. mulsi3 requires 16
// instructions (including the prologue and epilogue but excluding instructions
// at call site). Until we can inline mulsi3, generating at most 14 instructions
// will be faster than invoking mulsi3.
static cl::opt<int> LanaiLowerConstantMulThreshold(
"lanai-constant-mul-threshold", cl::Hidden,
cl::desc("Maximum number of instruction to generate when lowering constant "
"multiplication instead of calling library function [default=14]"),
cl::init(14));
LanaiTargetLowering::LanaiTargetLowering(const TargetMachine &TM,
const LanaiSubtarget &STI)
: TargetLowering(TM) {
// Set up the register classes.
addRegisterClass(MVT::i32, &Lanai::GPRRegClass);
// Compute derived properties from the register classes
TRI = STI.getRegisterInfo();
computeRegisterProperties(TRI);
setStackPointerRegisterToSaveRestore(Lanai::SP);
setOperationAction(ISD::BR_CC, MVT::i32, Custom);
setOperationAction(ISD::BR_JT, MVT::Other, Expand);
setOperationAction(ISD::BRCOND, MVT::Other, Expand);
setOperationAction(ISD::SETCC, MVT::i32, Custom);
setOperationAction(ISD::SELECT, MVT::i32, Expand);
setOperationAction(ISD::SELECT_CC, MVT::i32, Custom);
setOperationAction(ISD::GlobalAddress, MVT::i32, Custom);
setOperationAction(ISD::BlockAddress, MVT::i32, Custom);
setOperationAction(ISD::JumpTable, MVT::i32, Custom);
setOperationAction(ISD::ConstantPool, MVT::i32, Custom);
setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Custom);
setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
setOperationAction(ISD::VASTART, MVT::Other, Custom);
setOperationAction(ISD::VAARG, MVT::Other, Expand);
setOperationAction(ISD::VACOPY, MVT::Other, Expand);
setOperationAction(ISD::VAEND, MVT::Other, Expand);
setOperationAction(ISD::SDIV, MVT::i32, Expand);
setOperationAction(ISD::UDIV, MVT::i32, Expand);
setOperationAction(ISD::SDIVREM, MVT::i32, Expand);
setOperationAction(ISD::UDIVREM, MVT::i32, Expand);
setOperationAction(ISD::SREM, MVT::i32, Expand);
setOperationAction(ISD::UREM, MVT::i32, Expand);
setOperationAction(ISD::MUL, MVT::i32, Custom);
setOperationAction(ISD::MULHU, MVT::i32, Expand);
setOperationAction(ISD::MULHS, MVT::i32, Expand);
setOperationAction(ISD::UMUL_LOHI, MVT::i32, Expand);
setOperationAction(ISD::SMUL_LOHI, MVT::i32, Expand);
setOperationAction(ISD::ROTR, MVT::i32, Expand);
setOperationAction(ISD::ROTL, MVT::i32, Expand);
setOperationAction(ISD::SHL_PARTS, MVT::i32, Custom);
setOperationAction(ISD::SRL_PARTS, MVT::i32, Custom);
setOperationAction(ISD::SRA_PARTS, MVT::i32, Expand);
setOperationAction(ISD::BSWAP, MVT::i32, Expand);
setOperationAction(ISD::CTPOP, MVT::i32, Legal);
setOperationAction(ISD::CTLZ, MVT::i32, Legal);
setOperationAction(ISD::CTTZ, MVT::i32, Legal);
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand);
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i8, Expand);
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i16, Expand);
// Extended load operations for i1 types must be promoted
for (MVT VT : MVT::integer_valuetypes()) {
setLoadExtAction(ISD::EXTLOAD, VT, MVT::i1, Promote);
setLoadExtAction(ISD::ZEXTLOAD, VT, MVT::i1, Promote);
setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i1, Promote);
}
setTargetDAGCombine(ISD::ADD);
setTargetDAGCombine(ISD::SUB);
setTargetDAGCombine(ISD::AND);
setTargetDAGCombine(ISD::OR);
setTargetDAGCombine(ISD::XOR);
// Function alignments
setMinFunctionAlignment(Align(4));
setPrefFunctionAlignment(Align(4));
setJumpIsExpensive(true);
// TODO: Setting the minimum jump table entries needed before a
// switch is transformed to a jump table to 100 to avoid creating jump tables
// as this was causing bad performance compared to a large group of if
// statements. Re-evaluate this on new benchmarks.
setMinimumJumpTableEntries(100);
// Use fast calling convention for library functions.
for (int I = 0; I < RTLIB::UNKNOWN_LIBCALL; ++I) {
setLibcallCallingConv(static_cast<RTLIB::Libcall>(I), CallingConv::Fast);
}
MaxStoresPerMemset = 16; // For @llvm.memset -> sequence of stores
MaxStoresPerMemsetOptSize = 8;
MaxStoresPerMemcpy = 16; // For @llvm.memcpy -> sequence of stores
MaxStoresPerMemcpyOptSize = 8;
MaxStoresPerMemmove = 16; // For @llvm.memmove -> sequence of stores
MaxStoresPerMemmoveOptSize = 8;
// Booleans always contain 0 or 1.
setBooleanContents(ZeroOrOneBooleanContent);
}
SDValue LanaiTargetLowering::LowerOperation(SDValue Op,
SelectionDAG &DAG) const {
switch (Op.getOpcode()) {
case ISD::MUL:
return LowerMUL(Op, DAG);
case ISD::BR_CC:
return LowerBR_CC(Op, DAG);
case ISD::ConstantPool:
return LowerConstantPool(Op, DAG);
case ISD::GlobalAddress:
return LowerGlobalAddress(Op, DAG);
case ISD::BlockAddress:
return LowerBlockAddress(Op, DAG);
case ISD::JumpTable:
return LowerJumpTable(Op, DAG);
case ISD::SELECT_CC:
return LowerSELECT_CC(Op, DAG);
case ISD::SETCC:
return LowerSETCC(Op, DAG);
case ISD::SHL_PARTS:
return LowerSHL_PARTS(Op, DAG);
case ISD::SRL_PARTS:
return LowerSRL_PARTS(Op, DAG);
case ISD::VASTART:
return LowerVASTART(Op, DAG);
case ISD::DYNAMIC_STACKALLOC:
return LowerDYNAMIC_STACKALLOC(Op, DAG);
case ISD::RETURNADDR:
return LowerRETURNADDR(Op, DAG);
case ISD::FRAMEADDR:
return LowerFRAMEADDR(Op, DAG);
default:
llvm_unreachable("unimplemented operand");
}
}
//===----------------------------------------------------------------------===//
// Lanai Inline Assembly Support
//===----------------------------------------------------------------------===//
Register LanaiTargetLowering::getRegisterByName(
const char *RegName, LLT /*VT*/,
const MachineFunction & /*MF*/) const {
// Only unallocatable registers should be matched here.
Register Reg = StringSwitch<unsigned>(RegName)
.Case("pc", Lanai::PC)
.Case("sp", Lanai::SP)
.Case("fp", Lanai::FP)
.Case("rr1", Lanai::RR1)
.Case("r10", Lanai::R10)
.Case("rr2", Lanai::RR2)
.Case("r11", Lanai::R11)
.Case("rca", Lanai::RCA)
.Default(0);
if (Reg)
return Reg;
report_fatal_error("Invalid register name global variable");
}
std::pair<unsigned, const TargetRegisterClass *>
LanaiTargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
StringRef Constraint,
MVT VT) const {
if (Constraint.size() == 1)
// GCC Constraint Letters
switch (Constraint[0]) {
case 'r': // GENERAL_REGS
return std::make_pair(0U, &Lanai::GPRRegClass);
default:
break;
}
return TargetLowering::getRegForInlineAsmConstraint(TRI, Constraint, VT);
}
// Examine constraint type and operand type and determine a weight value.
// This object must already have been set up with the operand type
// and the current alternative constraint selected.
TargetLowering::ConstraintWeight
LanaiTargetLowering::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.
if (CallOperandVal == nullptr)
return CW_Default;
// Look at the constraint type.
switch (*Constraint) {
case 'I': // signed 16 bit immediate
case 'J': // integer zero
case 'K': // unsigned 16 bit immediate
case 'L': // immediate in the range 0 to 31
case 'M': // signed 32 bit immediate where lower 16 bits are 0
case 'N': // signed 26 bit immediate
case 'O': // integer zero
if (isa<ConstantInt>(CallOperandVal))
Weight = CW_Constant;
break;
default:
Weight = TargetLowering::getSingleConstraintMatchWeight(Info, Constraint);
break;
}
return Weight;
}
// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
// vector. If it is invalid, don't add anything to Ops.
void LanaiTargetLowering::LowerAsmOperandForConstraint(
SDValue Op, std::string &Constraint, std::vector<SDValue> &Ops,
SelectionDAG &DAG) const {
SDValue Result(nullptr, 0);
// Only support length 1 constraints for now.
if (Constraint.length() > 1)
return;
char ConstraintLetter = Constraint[0];
switch (ConstraintLetter) {
case 'I': // Signed 16 bit constant
// If this fails, the parent routine will give an error
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
if (isInt<16>(C->getSExtValue())) {
Result = DAG.getTargetConstant(C->getSExtValue(), SDLoc(C),
Op.getValueType());
break;
}
}
return;
case 'J': // integer zero
case 'O':
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
if (C->getZExtValue() == 0) {
Result = DAG.getTargetConstant(0, SDLoc(C), Op.getValueType());
break;
}
}
return;
case 'K': // unsigned 16 bit immediate
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
if (isUInt<16>(C->getZExtValue())) {
Result = DAG.getTargetConstant(C->getSExtValue(), SDLoc(C),
Op.getValueType());
break;
}
}
return;
case 'L': // immediate in the range 0 to 31
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
if (C->getZExtValue() <= 31) {
Result = DAG.getTargetConstant(C->getZExtValue(), SDLoc(C),
Op.getValueType());
break;
}
}
return;
case 'M': // signed 32 bit immediate where lower 16 bits are 0
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
int64_t Val = C->getSExtValue();
if ((isInt<32>(Val)) && ((Val & 0xffff) == 0)) {
Result = DAG.getTargetConstant(Val, SDLoc(C), Op.getValueType());
break;
}
}
return;
case 'N': // signed 26 bit immediate
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
int64_t Val = C->getSExtValue();
if ((Val >= -33554432) && (Val <= 33554431)) {
Result = DAG.getTargetConstant(Val, SDLoc(C), Op.getValueType());
break;
}
}
return;
default:
break; // This will fall through to the generic implementation
}
if (Result.getNode()) {
Ops.push_back(Result);
return;
}
TargetLowering::LowerAsmOperandForConstraint(Op, Constraint, Ops, DAG);
}
//===----------------------------------------------------------------------===//
// Calling Convention Implementation
//===----------------------------------------------------------------------===//
#include "LanaiGenCallingConv.inc"
static unsigned NumFixedArgs;
static bool CC_Lanai32_VarArg(unsigned ValNo, MVT ValVT, MVT LocVT,
CCValAssign::LocInfo LocInfo,
ISD::ArgFlagsTy ArgFlags, CCState &State) {
// Handle fixed arguments with default CC.
// Note: Both the default and fast CC handle VarArg the same and hence the
// calling convention of the function is not considered here.
if (ValNo < NumFixedArgs) {
return CC_Lanai32(ValNo, ValVT, LocVT, LocInfo, ArgFlags, State);
}
// Promote i8/i16 args to i32
if (LocVT == MVT::i8 || LocVT == MVT::i16) {
LocVT = MVT::i32;
if (ArgFlags.isSExt())
LocInfo = CCValAssign::SExt;
else if (ArgFlags.isZExt())
LocInfo = CCValAssign::ZExt;
else
LocInfo = CCValAssign::AExt;
}
// VarArgs get passed on stack
unsigned Offset = State.AllocateStack(4, Align(4));
State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo));
return false;
}
SDValue LanaiTargetLowering::LowerFormalArguments(
SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &DL,
SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
switch (CallConv) {
case CallingConv::C:
case CallingConv::Fast:
return LowerCCCArguments(Chain, CallConv, IsVarArg, Ins, DL, DAG, InVals);
default:
report_fatal_error("Unsupported calling convention");
}
}
SDValue LanaiTargetLowering::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;
// Lanai target does not yet support tail call optimization.
IsTailCall = false;
switch (CallConv) {
case CallingConv::Fast:
case CallingConv::C:
return LowerCCCCallTo(Chain, Callee, CallConv, IsVarArg, IsTailCall, Outs,
OutVals, Ins, DL, DAG, InVals);
default:
report_fatal_error("Unsupported calling convention");
}
}
// LowerCCCArguments - transform physical registers into virtual registers and
// generate load operations for arguments places on the stack.
SDValue LanaiTargetLowering::LowerCCCArguments(
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();
MachineRegisterInfo &RegInfo = MF.getRegInfo();
LanaiMachineFunctionInfo *LanaiMFI = MF.getInfo<LanaiMachineFunctionInfo>();
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), ArgLocs,
*DAG.getContext());
if (CallConv == CallingConv::Fast) {
CCInfo.AnalyzeFormalArguments(Ins, CC_Lanai32_Fast);
} else {
CCInfo.AnalyzeFormalArguments(Ins, CC_Lanai32);
}
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
if (VA.isRegLoc()) {
// Arguments passed in registers
EVT RegVT = VA.getLocVT();
switch (RegVT.getSimpleVT().SimpleTy) {
case MVT::i32: {
Register VReg = RegInfo.createVirtualRegister(&Lanai::GPRRegClass);
RegInfo.addLiveIn(VA.getLocReg(), VReg);
SDValue ArgValue = DAG.getCopyFromReg(Chain, DL, VReg, RegVT);
// If this is an 8/16-bit value, it is really passed promoted to 32
// bits. Insert an assert[sz]ext to capture this, then truncate to the
// right size.
if (VA.getLocInfo() == CCValAssign::SExt)
ArgValue = DAG.getNode(ISD::AssertSext, DL, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
else if (VA.getLocInfo() == CCValAssign::ZExt)
ArgValue = DAG.getNode(ISD::AssertZext, DL, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
if (VA.getLocInfo() != CCValAssign::Full)
ArgValue = DAG.getNode(ISD::TRUNCATE, DL, VA.getValVT(), ArgValue);
InVals.push_back(ArgValue);
break;
}
default:
LLVM_DEBUG(dbgs() << "LowerFormalArguments Unhandled argument type: "
<< RegVT.getEVTString() << "\n");
llvm_unreachable("unhandled argument type");
}
} else {
// Sanity check
assert(VA.isMemLoc());
// Load the argument to a virtual register
unsigned ObjSize = VA.getLocVT().getSizeInBits() / 8;
// Check that the argument fits in stack slot
if (ObjSize > 4) {
errs() << "LowerFormalArguments Unhandled argument type: "
<< EVT(VA.getLocVT()).getEVTString() << "\n";
}
// Create the frame index object for this incoming parameter...
int FI = MFI.CreateFixedObject(ObjSize, VA.getLocMemOffset(), true);
// Create the SelectionDAG nodes corresponding to a load
// from this parameter
SDValue FIN = DAG.getFrameIndex(FI, MVT::i32);
InVals.push_back(DAG.getLoad(
VA.getLocVT(), DL, Chain, FIN,
MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), FI)));
}
}
// The Lanai ABI for returning structs by value requires that we copy
// the sret argument into rv for the return. Save the argument into
// a virtual register so that we can access it from the return points.
if (MF.getFunction().hasStructRetAttr()) {
unsigned Reg = LanaiMFI->getSRetReturnReg();
if (!Reg) {
Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i32));
LanaiMFI->setSRetReturnReg(Reg);
}
SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), DL, Reg, InVals[0]);
Chain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Copy, Chain);
}
if (IsVarArg) {
// Record the frame index of the first variable argument
// which is a value necessary to VASTART.
int FI = MFI.CreateFixedObject(4, CCInfo.getNextStackOffset(), true);
LanaiMFI->setVarArgsFrameIndex(FI);
}
return Chain;
}
SDValue
LanaiTargetLowering::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 a location
SmallVector<CCValAssign, 16> RVLocs;
// CCState - Info about the registers and stack slot.
CCState CCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), RVLocs,
*DAG.getContext());
// Analize return values.
CCInfo.AnalyzeReturn(Outs, RetCC_Lanai32);
SDValue Flag;
SmallVector<SDValue, 4> RetOps(1, Chain);
// Copy the result values into the output registers.
for (unsigned i = 0; i != RVLocs.size(); ++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()));
}
// The Lanai ABI for returning structs by value requires that we copy
// the sret argument into rv for the return. We saved the argument into
// a virtual register in the entry block, so now we copy the value out
// and into rv.
if (DAG.getMachineFunction().getFunction().hasStructRetAttr()) {
MachineFunction &MF = DAG.getMachineFunction();
LanaiMachineFunctionInfo *LanaiMFI = MF.getInfo<LanaiMachineFunctionInfo>();
unsigned Reg = LanaiMFI->getSRetReturnReg();
assert(Reg &&
"SRetReturnReg should have been set in LowerFormalArguments().");
SDValue Val =
DAG.getCopyFromReg(Chain, DL, Reg, getPointerTy(DAG.getDataLayout()));
Chain = DAG.getCopyToReg(Chain, DL, Lanai::RV, Val, Flag);
Flag = Chain.getValue(1);
RetOps.push_back(
DAG.getRegister(Lanai::RV, getPointerTy(DAG.getDataLayout())));
}
RetOps[0] = Chain; // Update chain
unsigned Opc = LanaiISD::RET_FLAG;
if (Flag.getNode())
RetOps.push_back(Flag);
// Return Void
return DAG.getNode(Opc, DL, MVT::Other,
ArrayRef<SDValue>(&RetOps[0], RetOps.size()));
}
// LowerCCCCallTo - functions arguments are copied from virtual regs to
// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
SDValue LanaiTargetLowering::LowerCCCCallTo(
SDValue Chain, SDValue Callee, CallingConv::ID CallConv, bool IsVarArg,
bool /*IsTailCall*/, const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals,
const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &DL,
SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
// Analyze operands of the call, assigning locations to each operand.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), ArgLocs,
*DAG.getContext());
GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee);
MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
NumFixedArgs = 0;
if (IsVarArg && G) {
const Function *CalleeFn = dyn_cast<Function>(G->getGlobal());
if (CalleeFn)
NumFixedArgs = CalleeFn->getFunctionType()->getNumParams();
}
if (NumFixedArgs)
CCInfo.AnalyzeCallOperands(Outs, CC_Lanai32_VarArg);
else {
if (CallConv == CallingConv::Fast)
CCInfo.AnalyzeCallOperands(Outs, CC_Lanai32_Fast);
else
CCInfo.AnalyzeCallOperands(Outs, CC_Lanai32);
}
// Get a count of how many bytes are to be pushed on the stack.
unsigned NumBytes = CCInfo.getNextStackOffset();
// Create local copies for byval args.
SmallVector<SDValue, 8> ByValArgs;
for (unsigned I = 0, E = Outs.size(); I != E; ++I) {
ISD::ArgFlagsTy Flags = Outs[I].Flags;
if (!Flags.isByVal())
continue;
SDValue Arg = OutVals[I];
unsigned Size = Flags.getByValSize();
Align Alignment = Flags.getNonZeroByValAlign();
int FI = MFI.CreateStackObject(Size, Alignment, false);
SDValue FIPtr = DAG.getFrameIndex(FI, getPointerTy(DAG.getDataLayout()));
SDValue SizeNode = DAG.getConstant(Size, DL, MVT::i32);
Chain = DAG.getMemcpy(Chain, DL, FIPtr, Arg, SizeNode, Alignment,
/*IsVolatile=*/false,
/*AlwaysInline=*/false,
/*isTailCall=*/false, MachinePointerInfo(),
MachinePointerInfo());
ByValArgs.push_back(FIPtr);
}
Chain = DAG.getCALLSEQ_START(Chain, NumBytes, 0, DL);
SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
SmallVector<SDValue, 12> MemOpChains;
SDValue StackPtr;
// Walk the register/memloc assignments, inserting copies/loads.
for (unsigned I = 0, J = 0, E = ArgLocs.size(); I != E; ++I) {
CCValAssign &VA = ArgLocs[I];
SDValue Arg = OutVals[I];
ISD::ArgFlagsTy Flags = Outs[I].Flags;
// Promote the value if needed.
switch (VA.getLocInfo()) {
case CCValAssign::Full:
break;
case CCValAssign::SExt:
Arg = DAG.getNode(ISD::SIGN_EXTEND, DL, VA.getLocVT(), Arg);
break;
case CCValAssign::ZExt:
Arg = DAG.getNode(ISD::ZERO_EXTEND, DL, VA.getLocVT(), Arg);
break;
case CCValAssign::AExt:
Arg = DAG.getNode(ISD::ANY_EXTEND, DL, VA.getLocVT(), Arg);
break;
default:
llvm_unreachable("Unknown loc info!");
}
// Use local copy if it is a byval arg.
if (Flags.isByVal())
Arg = ByValArgs[J++];
// Arguments that can be passed on register must be kept at RegsToPass
// vector
if (VA.isRegLoc()) {
RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
} else {
assert(VA.isMemLoc());
if (StackPtr.getNode() == nullptr)
StackPtr = DAG.getCopyFromReg(Chain, DL, Lanai::SP,
getPointerTy(DAG.getDataLayout()));
SDValue PtrOff =
DAG.getNode(ISD::ADD, DL, getPointerTy(DAG.getDataLayout()), StackPtr,
DAG.getIntPtrConstant(VA.getLocMemOffset(), DL));
MemOpChains.push_back(
DAG.getStore(Chain, DL, Arg, PtrOff, MachinePointerInfo()));
}
}
// Transform all store nodes into one single node because all store nodes are
// independent of each other.
if (!MemOpChains.empty())
Chain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other,
ArrayRef<SDValue>(&MemOpChains[0], MemOpChains.size()));
SDValue InFlag;
// 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 emitted instructions must be stuck together.
for (unsigned I = 0, E = RegsToPass.size(); I != E; ++I) {
Chain = DAG.getCopyToReg(Chain, DL, RegsToPass[I].first,
RegsToPass[I].second, InFlag);
InFlag = Chain.getValue(1);
}
// If the callee is a GlobalAddress node (quite common, every direct call is)
// turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
// Likewise ExternalSymbol -> TargetExternalSymbol.
uint8_t OpFlag = LanaiII::MO_NO_FLAG;
if (G) {
Callee = DAG.getTargetGlobalAddress(
G->getGlobal(), DL, getPointerTy(DAG.getDataLayout()), 0, OpFlag);
} else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee)) {
Callee = DAG.getTargetExternalSymbol(
E->getSymbol(), getPointerTy(DAG.getDataLayout()), OpFlag);
}
// 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 a register mask operand representing the call-preserved registers.
// TODO: Should return-twice functions be handled?
const uint32_t *Mask =
TRI->getCallPreservedMask(DAG.getMachineFunction(), CallConv);
assert(Mask && "Missing call preserved mask for calling convention");
Ops.push_back(DAG.getRegisterMask(Mask));
// Add argument registers to the end of the list so that they are
// known live into the call.
for (unsigned I = 0, E = RegsToPass.size(); I != E; ++I)
Ops.push_back(DAG.getRegister(RegsToPass[I].first,
RegsToPass[I].second.getValueType()));
if (InFlag.getNode())
Ops.push_back(InFlag);
Chain = DAG.getNode(LanaiISD::CALL, DL, NodeTys,
ArrayRef<SDValue>(&Ops[0], Ops.size()));
InFlag = Chain.getValue(1);
// Create the CALLSEQ_END node.
Chain = DAG.getCALLSEQ_END(
Chain,
DAG.getConstant(NumBytes, DL, getPointerTy(DAG.getDataLayout()), true),
DAG.getConstant(0, DL, getPointerTy(DAG.getDataLayout()), true), InFlag,
DL);
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);
}
// LowerCallResult - Lower the result values of a call into the
// appropriate copies out of appropriate physical registers.
SDValue LanaiTargetLowering::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());
CCInfo.AnalyzeCallResult(Ins, RetCC_Lanai32);
// Copy all of the result registers out of their specified physreg.
for (unsigned I = 0; I != RVLocs.size(); ++I) {
Chain = DAG.getCopyFromReg(Chain, DL, RVLocs[I].getLocReg(),
RVLocs[I].getValVT(), InFlag)
.getValue(1);
InFlag = Chain.getValue(2);
InVals.push_back(Chain.getValue(0));
}
return Chain;
}
//===----------------------------------------------------------------------===//
// Custom Lowerings
//===----------------------------------------------------------------------===//
static LPCC::CondCode IntCondCCodeToICC(SDValue CC, const SDLoc &DL,
SDValue &RHS, SelectionDAG &DAG) {
ISD::CondCode SetCCOpcode = cast<CondCodeSDNode>(CC)->get();
// For integer, only the SETEQ, SETNE, SETLT, SETLE, SETGT, SETGE, SETULT,
// SETULE, SETUGT, and SETUGE opcodes are used (see CodeGen/ISDOpcodes.h)
// and Lanai only supports integer comparisons, so only provide definitions
// for them.
switch (SetCCOpcode) {
case ISD::SETEQ:
return LPCC::ICC_EQ;
case ISD::SETGT:
if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS))
if (RHSC->getZExtValue() == 0xFFFFFFFF) {
// X > -1 -> X >= 0 -> is_plus(X)
RHS = DAG.getConstant(0, DL, RHS.getValueType());
return LPCC::ICC_PL;
}
return LPCC::ICC_GT;
case ISD::SETUGT:
return LPCC::ICC_UGT;
case ISD::SETLT:
if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS))
if (RHSC->getZExtValue() == 0)
// X < 0 -> is_minus(X)
return LPCC::ICC_MI;
return LPCC::ICC_LT;
case ISD::SETULT:
return LPCC::ICC_ULT;
case ISD::SETLE:
if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS))
if (RHSC->getZExtValue() == 0xFFFFFFFF) {
// X <= -1 -> X < 0 -> is_minus(X)
RHS = DAG.getConstant(0, DL, RHS.getValueType());
return LPCC::ICC_MI;
}
return LPCC::ICC_LE;
case ISD::SETULE:
return LPCC::ICC_ULE;
case ISD::SETGE:
if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(RHS))
if (RHSC->getZExtValue() == 0)
// X >= 0 -> is_plus(X)
return LPCC::ICC_PL;
return LPCC::ICC_GE;
case ISD::SETUGE:
return LPCC::ICC_UGE;
case ISD::SETNE:
return LPCC::ICC_NE;
case ISD::SETONE:
case ISD::SETUNE:
case ISD::SETOGE:
case ISD::SETOLE:
case ISD::SETOLT:
case ISD::SETOGT:
case ISD::SETOEQ:
case ISD::SETUEQ:
case ISD::SETO:
case ISD::SETUO:
llvm_unreachable("Unsupported comparison.");
default:
llvm_unreachable("Unknown integer condition code!");
}
}
SDValue LanaiTargetLowering::LowerBR_CC(SDValue Op, SelectionDAG &DAG) const {
SDValue Chain = Op.getOperand(0);
SDValue Cond = Op.getOperand(1);
SDValue LHS = Op.getOperand(2);
SDValue RHS = Op.getOperand(3);
SDValue Dest = Op.getOperand(4);
SDLoc DL(Op);
LPCC::CondCode CC = IntCondCCodeToICC(Cond, DL, RHS, DAG);
SDValue TargetCC = DAG.getConstant(CC, DL, MVT::i32);
SDValue Flag =
DAG.getNode(LanaiISD::SET_FLAG, DL, MVT::Glue, LHS, RHS, TargetCC);
return DAG.getNode(LanaiISD::BR_CC, DL, Op.getValueType(), Chain, Dest,
TargetCC, Flag);
}
SDValue LanaiTargetLowering::LowerMUL(SDValue Op, SelectionDAG &DAG) const {
EVT VT = Op->getValueType(0);
if (VT != MVT::i32)
return SDValue();
ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op->getOperand(1));
if (!C)
return SDValue();
int64_t MulAmt = C->getSExtValue();
int32_t HighestOne = -1;
uint32_t NonzeroEntries = 0;
int SignedDigit[32] = {0};
// Convert to non-adjacent form (NAF) signed-digit representation.
// NAF is a signed-digit form where no adjacent digits are non-zero. It is the
// minimal Hamming weight representation of a number (on average 1/3 of the
// digits will be non-zero vs 1/2 for regular binary representation). And as
// the non-zero digits will be the only digits contributing to the instruction
// count, this is desirable. The next loop converts it to NAF (following the
// approach in 'Guide to Elliptic Curve Cryptography' [ISBN: 038795273X]) by
// choosing the non-zero coefficients such that the resulting quotient is
// divisible by 2 which will cause the next coefficient to be zero.
int64_t E = std::abs(MulAmt);
int S = (MulAmt < 0 ? -1 : 1);
int I = 0;
while (E > 0) {
int ZI = 0;
if (E % 2 == 1) {
ZI = 2 - (E % 4);
if (ZI != 0)
++NonzeroEntries;
}
SignedDigit[I] = S * ZI;
if (SignedDigit[I] == 1)
HighestOne = I;
E = (E - ZI) / 2;
++I;
}
// Compute number of instructions required. Due to differences in lowering
// between the different processors this count is not exact.
// Start by assuming a shift and a add/sub for every non-zero entry (hence
// every non-zero entry requires 1 shift and 1 add/sub except for the first
// entry).
int32_t InstrRequired = 2 * NonzeroEntries - 1;
// Correct possible over-adding due to shift by 0 (which is not emitted).
if (std::abs(MulAmt) % 2 == 1)
--InstrRequired;
// Return if the form generated would exceed the instruction threshold.
if (InstrRequired > LanaiLowerConstantMulThreshold)
return SDValue();
SDValue Res;
SDLoc DL(Op);
SDValue V = Op->getOperand(0);
// Initialize the running sum. Set the running sum to the maximal shifted
// positive value (i.e., largest i such that zi == 1 and MulAmt has V<<i as a
// term NAF).
if (HighestOne == -1)
Res = DAG.getConstant(0, DL, MVT::i32);
else {
Res = DAG.getNode(ISD::SHL, DL, VT, V,
DAG.getConstant(HighestOne, DL, MVT::i32));
SignedDigit[HighestOne] = 0;
}
// Assemble multiplication from shift, add, sub using NAF form and running
// sum.
for (unsigned int I = 0; I < sizeof(SignedDigit) / sizeof(SignedDigit[0]);
++I) {
if (SignedDigit[I] == 0)
continue;
// Shifted multiplicand (v<<i).
SDValue Op =
DAG.getNode(ISD::SHL, DL, VT, V, DAG.getConstant(I, DL, MVT::i32));
if (SignedDigit[I] == 1)
Res = DAG.getNode(ISD::ADD, DL, VT, Res, Op);
else if (SignedDigit[I] == -1)
Res = DAG.getNode(ISD::SUB, DL, VT, Res, Op);
}
return Res;
}
SDValue LanaiTargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) const {
SDValue LHS = Op.getOperand(0);
SDValue RHS = Op.getOperand(1);
SDValue Cond = Op.getOperand(2);
SDLoc DL(Op);
LPCC::CondCode CC = IntCondCCodeToICC(Cond, DL, RHS, DAG);
SDValue TargetCC = DAG.getConstant(CC, DL, MVT::i32);
SDValue Flag =
DAG.getNode(LanaiISD::SET_FLAG, DL, MVT::Glue, LHS, RHS, TargetCC);
return DAG.getNode(LanaiISD::SETCC, DL, Op.getValueType(), TargetCC, Flag);
}
SDValue LanaiTargetLowering::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);
SDValue Cond = Op.getOperand(4);
SDLoc DL(Op);
LPCC::CondCode CC = IntCondCCodeToICC(Cond, DL, RHS, DAG);
SDValue TargetCC = DAG.getConstant(CC, DL, MVT::i32);
SDValue Flag =
DAG.getNode(LanaiISD::SET_FLAG, DL, MVT::Glue, LHS, RHS, TargetCC);
SDVTList VTs = DAG.getVTList(Op.getValueType(), MVT::Glue);
return DAG.getNode(LanaiISD::SELECT_CC, DL, VTs, TrueV, FalseV, TargetCC,
Flag);
}
SDValue LanaiTargetLowering::LowerVASTART(SDValue Op, SelectionDAG &DAG) const {
MachineFunction &MF = DAG.getMachineFunction();
LanaiMachineFunctionInfo *FuncInfo = MF.getInfo<LanaiMachineFunctionInfo>();
SDLoc DL(Op);
SDValue FI = DAG.getFrameIndex(FuncInfo->getVarArgsFrameIndex(),
getPointerTy(DAG.getDataLayout()));
// vastart just stores the address of the VarArgsFrameIndex slot into the
// memory location argument.
const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
return DAG.getStore(Op.getOperand(0), DL, FI, Op.getOperand(1),
MachinePointerInfo(SV));
}
SDValue LanaiTargetLowering::LowerDYNAMIC_STACKALLOC(SDValue Op,
SelectionDAG &DAG) const {
SDValue Chain = Op.getOperand(0);
SDValue Size = Op.getOperand(1);
SDLoc DL(Op);
Register SPReg = getStackPointerRegisterToSaveRestore();
// Get a reference to the stack pointer.
SDValue StackPointer = DAG.getCopyFromReg(Chain, DL, SPReg, MVT::i32);
// Subtract the dynamic size from the actual stack size to
// obtain the new stack size.
SDValue Sub = DAG.getNode(ISD::SUB, DL, MVT::i32, StackPointer, Size);
// For Lanai, the outgoing memory arguments area should be on top of the
// alloca area on the stack i.e., the outgoing memory arguments should be
// at a lower address than the alloca area. Move the alloca area down the
// stack by adding back the space reserved for outgoing arguments to SP
// here.
//
// We do not know what the size of the outgoing args is at this point.
// So, we add a pseudo instruction ADJDYNALLOC that will adjust the
// stack pointer. We replace this instruction with on that has the correct,
// known offset in emitPrologue().
SDValue ArgAdjust = DAG.getNode(LanaiISD::ADJDYNALLOC, DL, MVT::i32, Sub);
// The Sub result contains the new stack start address, so it
// must be placed in the stack pointer register.
SDValue CopyChain = DAG.getCopyToReg(Chain, DL, SPReg, Sub);
SDValue Ops[2] = {ArgAdjust, CopyChain};
return DAG.getMergeValues(Ops, DL);
}
SDValue LanaiTargetLowering::LowerRETURNADDR(SDValue Op,
SelectionDAG &DAG) const {
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo &MFI = MF.getFrameInfo();
MFI.setReturnAddressIsTaken(true);
EVT VT = Op.getValueType();
SDLoc DL(Op);
unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
if (Depth) {
SDValue FrameAddr = LowerFRAMEADDR(Op, DAG);
const unsigned Offset = -4;
SDValue Ptr = DAG.getNode(ISD::ADD, DL, VT, FrameAddr,
DAG.getIntPtrConstant(Offset, DL));
return DAG.getLoad(VT, DL, DAG.getEntryNode(), Ptr, MachinePointerInfo());
}
// Return the link register, which contains the return address.
// Mark it an implicit live-in.
unsigned Reg = MF.addLiveIn(TRI->getRARegister(), getRegClassFor(MVT::i32));
return DAG.getCopyFromReg(DAG.getEntryNode(), DL, Reg, VT);
}
SDValue LanaiTargetLowering::LowerFRAMEADDR(SDValue Op,
SelectionDAG &DAG) const {
MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
MFI.setFrameAddressIsTaken(true);
EVT VT = Op.getValueType();
SDLoc DL(Op);
SDValue FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), DL, Lanai::FP, VT);
unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
while (Depth--) {
const unsigned Offset = -8;
SDValue Ptr = DAG.getNode(ISD::ADD, DL, VT, FrameAddr,
DAG.getIntPtrConstant(Offset, DL));
FrameAddr =
DAG.getLoad(VT, DL, DAG.getEntryNode(), Ptr, MachinePointerInfo());
}
return FrameAddr;
}
const char *LanaiTargetLowering::getTargetNodeName(unsigned Opcode) const {
switch (Opcode) {
case LanaiISD::ADJDYNALLOC:
return "LanaiISD::ADJDYNALLOC";
case LanaiISD::RET_FLAG:
return "LanaiISD::RET_FLAG";
case LanaiISD::CALL:
return "LanaiISD::CALL";
case LanaiISD::SELECT_CC:
return "LanaiISD::SELECT_CC";
case LanaiISD::SETCC:
return "LanaiISD::SETCC";
case LanaiISD::SUBBF:
return "LanaiISD::SUBBF";
case LanaiISD::SET_FLAG:
return "LanaiISD::SET_FLAG";
case LanaiISD::BR_CC:
return "LanaiISD::BR_CC";
case LanaiISD::Wrapper:
return "LanaiISD::Wrapper";
case LanaiISD::HI:
return "LanaiISD::HI";
case LanaiISD::LO:
return "LanaiISD::LO";
case LanaiISD::SMALL:
return "LanaiISD::SMALL";
default:
return nullptr;
}
}
SDValue LanaiTargetLowering::LowerConstantPool(SDValue Op,
SelectionDAG &DAG) const {
SDLoc DL(Op);
ConstantPoolSDNode *N = cast<ConstantPoolSDNode>(Op);
const Constant *C = N->getConstVal();
const LanaiTargetObjectFile *TLOF =
static_cast<const LanaiTargetObjectFile *>(
getTargetMachine().getObjFileLowering());
// If the code model is small or constant will be placed in the small section,
// then assume address will fit in 21-bits.
if (getTargetMachine().getCodeModel() == CodeModel::Small ||
TLOF->isConstantInSmallSection(DAG.getDataLayout(), C)) {
SDValue Small = DAG.getTargetConstantPool(
C, MVT::i32, N->getAlign(), N->getOffset(), LanaiII::MO_NO_FLAG);
return DAG.getNode(ISD::OR, DL, MVT::i32,
DAG.getRegister(Lanai::R0, MVT::i32),
DAG.getNode(LanaiISD::SMALL, DL, MVT::i32, Small));
} else {
uint8_t OpFlagHi = LanaiII::MO_ABS_HI;
uint8_t OpFlagLo = LanaiII::MO_ABS_LO;
SDValue Hi = DAG.getTargetConstantPool(C, MVT::i32, N->getAlign(),
N->getOffset(), OpFlagHi);
SDValue Lo = DAG.getTargetConstantPool(C, MVT::i32, N->getAlign(),
N->getOffset(), OpFlagLo);
Hi = DAG.getNode(LanaiISD::HI, DL, MVT::i32, Hi);
Lo = DAG.getNode(LanaiISD::LO, DL, MVT::i32, Lo);
SDValue Result = DAG.getNode(ISD::OR, DL, MVT::i32, Hi, Lo);
return Result;
}
}
SDValue LanaiTargetLowering::LowerGlobalAddress(SDValue Op,
SelectionDAG &DAG) const {
SDLoc DL(Op);
const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
int64_t Offset = cast<GlobalAddressSDNode>(Op)->getOffset();
const LanaiTargetObjectFile *TLOF =
static_cast<const LanaiTargetObjectFile *>(
getTargetMachine().getObjFileLowering());
// If the code model is small or global variable will be placed in the small
// section, then assume address will fit in 21-bits.
const GlobalObject *GO = GV->getBaseObject();
if (TLOF->isGlobalInSmallSection(GO, getTargetMachine())) {
SDValue Small = DAG.getTargetGlobalAddress(
GV, DL, getPointerTy(DAG.getDataLayout()), Offset, LanaiII::MO_NO_FLAG);
return DAG.getNode(ISD::OR, DL, MVT::i32,
DAG.getRegister(Lanai::R0, MVT::i32),
DAG.getNode(LanaiISD::SMALL, DL, MVT::i32, Small));
} else {
uint8_t OpFlagHi = LanaiII::MO_ABS_HI;
uint8_t OpFlagLo = LanaiII::MO_ABS_LO;
// Create the TargetGlobalAddress node, folding in the constant offset.
SDValue Hi = DAG.getTargetGlobalAddress(
GV, DL, getPointerTy(DAG.getDataLayout()), Offset, OpFlagHi);
SDValue Lo = DAG.getTargetGlobalAddress(
GV, DL, getPointerTy(DAG.getDataLayout()), Offset, OpFlagLo);
Hi = DAG.getNode(LanaiISD::HI, DL, MVT::i32, Hi);
Lo = DAG.getNode(LanaiISD::LO, DL, MVT::i32, Lo);
return DAG.getNode(ISD::OR, DL, MVT::i32, Hi, Lo);
}
}
SDValue LanaiTargetLowering::LowerBlockAddress(SDValue Op,
SelectionDAG &DAG) const {
SDLoc DL(Op);
const BlockAddress *BA = cast<BlockAddressSDNode>(Op)->getBlockAddress();
uint8_t OpFlagHi = LanaiII::MO_ABS_HI;
uint8_t OpFlagLo = LanaiII::MO_ABS_LO;
SDValue Hi = DAG.getBlockAddress(BA, MVT::i32, true, OpFlagHi);
SDValue Lo = DAG.getBlockAddress(BA, MVT::i32, true, OpFlagLo);
Hi = DAG.getNode(LanaiISD::HI, DL, MVT::i32, Hi);
Lo = DAG.getNode(LanaiISD::LO, DL, MVT::i32, Lo);
SDValue Result = DAG.getNode(ISD::OR, DL, MVT::i32, Hi, Lo);
return Result;
}
SDValue LanaiTargetLowering::LowerJumpTable(SDValue Op,
SelectionDAG &DAG) const {
SDLoc DL(Op);
JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
// If the code model is small assume address will fit in 21-bits.
if (getTargetMachine().getCodeModel() == CodeModel::Small) {
SDValue Small = DAG.getTargetJumpTable(
JT->getIndex(), getPointerTy(DAG.getDataLayout()), LanaiII::MO_NO_FLAG);
return DAG.getNode(ISD::OR, DL, MVT::i32,
DAG.getRegister(Lanai::R0, MVT::i32),
DAG.getNode(LanaiISD::SMALL, DL, MVT::i32, Small));
} else {
uint8_t OpFlagHi = LanaiII::MO_ABS_HI;
uint8_t OpFlagLo = LanaiII::MO_ABS_LO;
SDValue Hi = DAG.getTargetJumpTable(
JT->getIndex(), getPointerTy(DAG.getDataLayout()), OpFlagHi);
SDValue Lo = DAG.getTargetJumpTable(
JT->getIndex(), getPointerTy(DAG.getDataLayout()), OpFlagLo);
Hi = DAG.getNode(LanaiISD::HI, DL, MVT::i32, Hi);
Lo = DAG.getNode(LanaiISD::LO, DL, MVT::i32, Lo);
SDValue Result = DAG.getNode(ISD::OR, DL, MVT::i32, Hi, Lo);
return Result;
}
}
SDValue LanaiTargetLowering::LowerSHL_PARTS(SDValue Op,
SelectionDAG &DAG) const {
EVT VT = Op.getValueType();
unsigned VTBits = VT.getSizeInBits();
SDLoc dl(Op);
assert(Op.getNumOperands() == 3 && "Unexpected SHL!");
SDValue ShOpLo = Op.getOperand(0);
SDValue ShOpHi = Op.getOperand(1);
SDValue ShAmt = Op.getOperand(2);
// Performs the following for (ShOpLo + (ShOpHi << 32)) << ShAmt:
// LoBitsForHi = (ShAmt == 0) ? 0 : (ShOpLo >> (32-ShAmt))
// HiBitsForHi = ShOpHi << ShAmt
// Hi = (ShAmt >= 32) ? (ShOpLo << (ShAmt-32)) : (LoBitsForHi | HiBitsForHi)
// Lo = (ShAmt >= 32) ? 0 : (ShOpLo << ShAmt)
// return (Hi << 32) | Lo;
SDValue RevShAmt = DAG.getNode(ISD::SUB, dl, MVT::i32,
DAG.getConstant(VTBits, dl, MVT::i32), ShAmt);
SDValue LoBitsForHi = DAG.getNode(ISD::SRL, dl, VT, ShOpLo, RevShAmt);
// If ShAmt == 0, we just calculated "(SRL ShOpLo, 32)" which is "undef". We
// wanted 0, so CSEL it directly.
SDValue Zero = DAG.getConstant(0, dl, MVT::i32);
SDValue SetCC = DAG.getSetCC(dl, MVT::i32, ShAmt, Zero, ISD::SETEQ);
LoBitsForHi = DAG.getSelect(dl, MVT::i32, SetCC, Zero, LoBitsForHi);
SDValue ExtraShAmt = DAG.getNode(ISD::SUB, dl, MVT::i32, ShAmt,
DAG.getConstant(VTBits, dl, MVT::i32));
SDValue HiBitsForHi = DAG.getNode(ISD::SHL, dl, VT, ShOpHi, ShAmt);
SDValue HiForNormalShift =
DAG.getNode(ISD::OR, dl, VT, LoBitsForHi, HiBitsForHi);
SDValue HiForBigShift = DAG.getNode(ISD::SHL, dl, VT, ShOpLo, ExtraShAmt);
SetCC = DAG.getSetCC(dl, MVT::i32, ExtraShAmt, Zero, ISD::SETGE);
SDValue Hi =
DAG.getSelect(dl, MVT::i32, SetCC, HiForBigShift, HiForNormalShift);
// Lanai shifts of larger than register sizes are wrapped rather than
// clamped, so we can't just emit "lo << b" if b is too big.
SDValue LoForNormalShift = DAG.getNode(ISD::SHL, dl, VT, ShOpLo, ShAmt);
SDValue Lo = DAG.getSelect(
dl, MVT::i32, SetCC, DAG.getConstant(0, dl, MVT::i32), LoForNormalShift);
SDValue Ops[2] = {Lo, Hi};
return DAG.getMergeValues(Ops, dl);
}
SDValue LanaiTargetLowering::LowerSRL_PARTS(SDValue Op,
SelectionDAG &DAG) const {
MVT VT = Op.getSimpleValueType();
unsigned VTBits = VT.getSizeInBits();
SDLoc dl(Op);
SDValue ShOpLo = Op.getOperand(0);
SDValue ShOpHi = Op.getOperand(1);
SDValue ShAmt = Op.getOperand(2);
// Performs the following for a >> b:
// unsigned r_high = a_high >> b;
// r_high = (32 - b <= 0) ? 0 : r_high;
//
// unsigned r_low = a_low >> b;
// r_low = (32 - b <= 0) ? r_high : r_low;
// r_low = (b == 0) ? r_low : r_low | (a_high << (32 - b));
// return (unsigned long long)r_high << 32 | r_low;
// Note: This takes advantage of Lanai's shift behavior to avoid needing to
// mask the shift amount.
SDValue Zero = DAG.getConstant(0, dl, MVT::i32);
SDValue NegatedPlus32 = DAG.getNode(
ISD::SUB, dl, MVT::i32, DAG.getConstant(VTBits, dl, MVT::i32), ShAmt);
SDValue SetCC = DAG.getSetCC(dl, MVT::i32, NegatedPlus32, Zero, ISD::SETLE);
SDValue Hi = DAG.getNode(ISD::SRL, dl, MVT::i32, ShOpHi, ShAmt);
Hi = DAG.getSelect(dl, MVT::i32, SetCC, Zero, Hi);
SDValue Lo = DAG.getNode(ISD::SRL, dl, MVT::i32, ShOpLo, ShAmt);
Lo = DAG.getSelect(dl, MVT::i32, SetCC, Hi, Lo);
SDValue CarryBits =
DAG.getNode(ISD::SHL, dl, MVT::i32, ShOpHi, NegatedPlus32);
SDValue ShiftIsZero = DAG.getSetCC(dl, MVT::i32, ShAmt, Zero, ISD::SETEQ);
Lo = DAG.getSelect(dl, MVT::i32, ShiftIsZero, Lo,
DAG.getNode(ISD::OR, dl, MVT::i32, Lo, CarryBits));
SDValue Ops[2] = {Lo, Hi};
return DAG.getMergeValues(Ops, dl);
}
// Helper function that checks if N is a null or all ones constant.
static inline bool isZeroOrAllOnes(SDValue N, bool AllOnes) {
return AllOnes ? isAllOnesConstant(N) : isNullConstant(N);
}
// Return true if N is conditionally 0 or all ones.
// Detects these expressions where cc is an i1 value:
//
// (select cc 0, y) [AllOnes=0]
// (select cc y, 0) [AllOnes=0]
// (zext cc) [AllOnes=0]
// (sext cc) [AllOnes=0/1]
// (select cc -1, y) [AllOnes=1]
// (select cc y, -1) [AllOnes=1]
//
// * AllOnes determines whether to check for an all zero (AllOnes false) or an
// all ones operand (AllOnes true).
// * Invert is set when N is the all zero/ones constant when CC is false.
// * OtherOp is set to the alternative value of N.
//
// For example, for (select cc X, Y) and AllOnes = 0 if:
// * X = 0, Invert = False and OtherOp = Y
// * Y = 0, Invert = True and OtherOp = X
static bool isConditionalZeroOrAllOnes(SDNode *N, bool AllOnes, SDValue &CC,
bool &Invert, SDValue &OtherOp,
SelectionDAG &DAG) {
switch (N->getOpcode()) {
default:
return false;
case ISD::SELECT: {
CC = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue N2 = N->getOperand(2);
if (isZeroOrAllOnes(N1, AllOnes)) {
Invert = false;
OtherOp = N2;
return true;
}
if (isZeroOrAllOnes(N2, AllOnes)) {
Invert = true;
OtherOp = N1;
return true;
}
return false;
}
case ISD::ZERO_EXTEND: {
// (zext cc) can never be the all ones value.
if (AllOnes)
return false;
CC = N->getOperand(0);
if (CC.getValueType() != MVT::i1)
return false;
SDLoc dl(N);
EVT VT = N->getValueType(0);
OtherOp = DAG.getConstant(1, dl, VT);
Invert = true;
return true;
}
case ISD::SIGN_EXTEND: {
CC = N->getOperand(0);
if (CC.getValueType() != MVT::i1)
return false;
SDLoc dl(N);
EVT VT = N->getValueType(0);
Invert = !AllOnes;
if (AllOnes)
// When looking for an AllOnes constant, N is an sext, and the 'other'
// value is 0.
OtherOp = DAG.getConstant(0, dl, VT);
else
OtherOp =
DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), dl, VT);
return true;
}
}
}
// Combine a constant select operand into its use:
//
// (add (select cc, 0, c), x) -> (select cc, x, (add, x, c))
// (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c))
// (and (select cc, -1, c), x) -> (select cc, x, (and, x, c)) [AllOnes=1]
// (or (select cc, 0, c), x) -> (select cc, x, (or, x, c))
// (xor (select cc, 0, c), x) -> (select cc, x, (xor, x, c))
//
// The transform is rejected if the select doesn't have a constant operand that
// is null, or all ones when AllOnes is set.
//
// Also recognize sext/zext from i1:
//
// (add (zext cc), x) -> (select cc (add x, 1), x)
// (add (sext cc), x) -> (select cc (add x, -1), x)
//
// These transformations eventually create predicated instructions.
static SDValue combineSelectAndUse(SDNode *N, SDValue Slct, SDValue OtherOp,
TargetLowering::DAGCombinerInfo &DCI,
bool AllOnes) {
SelectionDAG &DAG = DCI.DAG;
EVT VT = N->getValueType(0);
SDValue NonConstantVal;
SDValue CCOp;
bool SwapSelectOps;
if (!isConditionalZeroOrAllOnes(Slct.getNode(), AllOnes, CCOp, SwapSelectOps,
NonConstantVal, DAG))
return SDValue();
// Slct is now know to be the desired identity constant when CC is true.
SDValue TrueVal = OtherOp;
SDValue FalseVal =
DAG.getNode(N->getOpcode(), SDLoc(N), VT, OtherOp, NonConstantVal);
// Unless SwapSelectOps says CC should be false.
if (SwapSelectOps)
std::swap(TrueVal, FalseVal);
return DAG.getNode(ISD::SELECT, SDLoc(N), VT, CCOp, TrueVal, FalseVal);
}
// Attempt combineSelectAndUse on each operand of a commutative operator N.
static SDValue
combineSelectAndUseCommutative(SDNode *N, TargetLowering::DAGCombinerInfo &DCI,
bool AllOnes) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
if (N0.getNode()->hasOneUse())
if (SDValue Result = combineSelectAndUse(N, N0, N1, DCI, AllOnes))
return Result;
if (N1.getNode()->hasOneUse())
if (SDValue Result = combineSelectAndUse(N, N1, N0, DCI, AllOnes))
return Result;
return SDValue();
}
// PerformSUBCombine - Target-specific dag combine xforms for ISD::SUB.
static SDValue PerformSUBCombine(SDNode *N,
TargetLowering::DAGCombinerInfo &DCI) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
// fold (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c))
if (N1.getNode()->hasOneUse())
if (SDValue Result = combineSelectAndUse(N, N1, N0, DCI, /*AllOnes=*/false))
return Result;
return SDValue();
}
SDValue LanaiTargetLowering::PerformDAGCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
switch (N->getOpcode()) {
default:
break;
case ISD::ADD:
case ISD::OR:
case ISD::XOR:
return combineSelectAndUseCommutative(N, DCI, /*AllOnes=*/false);
case ISD::AND:
return combineSelectAndUseCommutative(N, DCI, /*AllOnes=*/true);
case ISD::SUB:
return PerformSUBCombine(N, DCI);
}
return SDValue();
}
void LanaiTargetLowering::computeKnownBitsForTargetNode(
const SDValue Op, KnownBits &Known, const APInt &DemandedElts,
const SelectionDAG &DAG, unsigned Depth) const {
unsigned BitWidth = Known.getBitWidth();
switch (Op.getOpcode()) {
default:
break;
case LanaiISD::SETCC:
Known = KnownBits(BitWidth);
Known.Zero.setBits(1, BitWidth);
break;
case LanaiISD::SELECT_CC:
KnownBits Known2;
Known = DAG.computeKnownBits(Op->getOperand(0), Depth + 1);
Known2 = DAG.computeKnownBits(Op->getOperand(1), Depth + 1);
Known = KnownBits::commonBits(Known, Known2);
break;
}
}
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