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llvm-project/llvm/lib/Target/R600/SIISelLowering.cpp

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//===-- SIISelLowering.cpp - SI DAG Lowering Implementation ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// \brief Custom DAG lowering for SI
//
//===----------------------------------------------------------------------===//
#include "SIISelLowering.h"
#include "AMDIL.h"
#include "AMDGPU.h"
#include "AMDILIntrinsicInfo.h"
#include "SIInstrInfo.h"
#include "SIMachineFunctionInfo.h"
#include "SIRegisterInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
using namespace llvm;
SITargetLowering::SITargetLowering(TargetMachine &TM) :
AMDGPUTargetLowering(TM),
TII(static_cast<const SIInstrInfo*>(TM.getInstrInfo())),
TRI(TM.getRegisterInfo()) {
addRegisterClass(MVT::i1, &AMDGPU::SReg_64RegClass);
addRegisterClass(MVT::i64, &AMDGPU::SReg_64RegClass);
addRegisterClass(MVT::v16i8, &AMDGPU::SReg_128RegClass);
addRegisterClass(MVT::v32i8, &AMDGPU::SReg_256RegClass);
addRegisterClass(MVT::v64i8, &AMDGPU::SReg_512RegClass);
addRegisterClass(MVT::i32, &AMDGPU::VReg_32RegClass);
addRegisterClass(MVT::f32, &AMDGPU::VReg_32RegClass);
addRegisterClass(MVT::v1i32, &AMDGPU::VReg_32RegClass);
addRegisterClass(MVT::v2i32, &AMDGPU::VReg_64RegClass);
addRegisterClass(MVT::v2f32, &AMDGPU::VReg_64RegClass);
addRegisterClass(MVT::v4i32, &AMDGPU::VReg_128RegClass);
addRegisterClass(MVT::v4f32, &AMDGPU::VReg_128RegClass);
addRegisterClass(MVT::i128, &AMDGPU::SReg_128RegClass);
addRegisterClass(MVT::v8i32, &AMDGPU::VReg_256RegClass);
addRegisterClass(MVT::v8f32, &AMDGPU::VReg_256RegClass);
addRegisterClass(MVT::v16i32, &AMDGPU::VReg_512RegClass);
addRegisterClass(MVT::v16f32, &AMDGPU::VReg_512RegClass);
computeRegisterProperties();
setOperationAction(ISD::VECTOR_SHUFFLE, MVT::v8i32, Expand);
setOperationAction(ISD::VECTOR_SHUFFLE, MVT::v8f32, Expand);
setOperationAction(ISD::VECTOR_SHUFFLE, MVT::v16i32, Expand);
setOperationAction(ISD::VECTOR_SHUFFLE, MVT::v16f32, Expand);
setOperationAction(ISD::ADD, MVT::i64, Legal);
setOperationAction(ISD::ADD, MVT::i32, Legal);
setOperationAction(ISD::SELECT_CC, MVT::f32, Custom);
setOperationAction(ISD::SELECT_CC, MVT::i32, Custom);
setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);
setOperationAction(ISD::STORE, MVT::i32, Custom);
setOperationAction(ISD::STORE, MVT::i64, Custom);
setTargetDAGCombine(ISD::SELECT_CC);
setTargetDAGCombine(ISD::SETCC);
setSchedulingPreference(Sched::RegPressure);
}
SDValue SITargetLowering::LowerFormalArguments(
SDValue Chain,
CallingConv::ID CallConv,
bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
DebugLoc DL, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const {
const TargetRegisterInfo *TRI = getTargetMachine().getRegisterInfo();
MachineFunction &MF = DAG.getMachineFunction();
FunctionType *FType = MF.getFunction()->getFunctionType();
SIMachineFunctionInfo *Info = MF.getInfo<SIMachineFunctionInfo>();
assert(CallConv == CallingConv::C);
SmallVector<ISD::InputArg, 16> Splits;
uint32_t Skipped = 0;
for (unsigned i = 0, e = Ins.size(), PSInputNum = 0; i != e; ++i) {
const ISD::InputArg &Arg = Ins[i];
// First check if it's a PS input addr
if (Info->ShaderType == ShaderType::PIXEL && !Arg.Flags.isInReg()) {
assert((PSInputNum <= 15) && "Too many PS inputs!");
if (!Arg.Used) {
// We can savely skip PS inputs
Skipped |= 1 << i;
++PSInputNum;
continue;
}
Info->PSInputAddr |= 1 << PSInputNum++;
}
// Second split vertices into their elements
if (Arg.VT.isVector()) {
ISD::InputArg NewArg = Arg;
NewArg.Flags.setSplit();
NewArg.VT = Arg.VT.getVectorElementType();
// We REALLY want the ORIGINAL number of vertex elements here, e.g. a
// three or five element vertex only needs three or five registers,
// NOT four or eigth.
Type *ParamType = FType->getParamType(Arg.OrigArgIndex);
unsigned NumElements = ParamType->getVectorNumElements();
for (unsigned j = 0; j != NumElements; ++j) {
Splits.push_back(NewArg);
NewArg.PartOffset += NewArg.VT.getStoreSize();
}
} else {
Splits.push_back(Arg);
}
}
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
getTargetMachine(), ArgLocs, *DAG.getContext());
// At least one interpolation mode must be enabled or else the GPU will hang.
if (Info->ShaderType == ShaderType::PIXEL && (Info->PSInputAddr & 0x7F) == 0) {
Info->PSInputAddr |= 1;
CCInfo.AllocateReg(AMDGPU::VGPR0);
CCInfo.AllocateReg(AMDGPU::VGPR1);
}
AnalyzeFormalArguments(CCInfo, Splits);
for (unsigned i = 0, e = Ins.size(), ArgIdx = 0; i != e; ++i) {
if (Skipped & (1 << i)) {
InVals.push_back(SDValue());
continue;
}
CCValAssign &VA = ArgLocs[ArgIdx++];
assert(VA.isRegLoc() && "Parameter must be in a register!");
unsigned Reg = VA.getLocReg();
MVT VT = VA.getLocVT();
if (VT == MVT::i64) {
// For now assume it is a pointer
Reg = TRI->getMatchingSuperReg(Reg, AMDGPU::sub0,
&AMDGPU::SReg_64RegClass);
Reg = MF.addLiveIn(Reg, &AMDGPU::SReg_64RegClass);
InVals.push_back(DAG.getCopyFromReg(Chain, DL, Reg, VT));
continue;
}
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg, VT);
Reg = MF.addLiveIn(Reg, RC);
SDValue Val = DAG.getCopyFromReg(Chain, DL, Reg, VT);
const ISD::InputArg &Arg = Ins[i];
if (Arg.VT.isVector()) {
// Build a vector from the registers
Type *ParamType = FType->getParamType(Arg.OrigArgIndex);
unsigned NumElements = ParamType->getVectorNumElements();
SmallVector<SDValue, 4> Regs;
Regs.push_back(Val);
for (unsigned j = 1; j != NumElements; ++j) {
Reg = ArgLocs[ArgIdx++].getLocReg();
Reg = MF.addLiveIn(Reg, RC);
Regs.push_back(DAG.getCopyFromReg(Chain, DL, Reg, VT));
}
// Fill up the missing vector elements
NumElements = Arg.VT.getVectorNumElements() - NumElements;
for (unsigned j = 0; j != NumElements; ++j)
Regs.push_back(DAG.getUNDEF(VT));
InVals.push_back(DAG.getNode(ISD::BUILD_VECTOR, DL, Arg.VT,
Regs.data(), Regs.size()));
continue;
}
InVals.push_back(Val);
}
return Chain;
}
MachineBasicBlock * SITargetLowering::EmitInstrWithCustomInserter(
MachineInstr * MI, MachineBasicBlock * BB) const {
switch (MI->getOpcode()) {
default:
return AMDGPUTargetLowering::EmitInstrWithCustomInserter(MI, BB);
case AMDGPU::BRANCH: return BB;
}
return BB;
}
EVT SITargetLowering::getSetCCResultType(EVT VT) const {
return MVT::i1;
}
MVT SITargetLowering::getScalarShiftAmountTy(EVT VT) const {
return MVT::i32;
}
//===----------------------------------------------------------------------===//
// Custom DAG Lowering Operations
//===----------------------------------------------------------------------===//
SDValue SITargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
switch (Op.getOpcode()) {
default: return AMDGPUTargetLowering::LowerOperation(Op, DAG);
case ISD::BRCOND: return LowerBRCOND(Op, DAG);
case ISD::SELECT_CC: return LowerSELECT_CC(Op, DAG);
case ISD::STORE: return LowerSTORE(Op, DAG);
}
return SDValue();
}
/// \brief Helper function for LowerBRCOND
static SDNode *findUser(SDValue Value, unsigned Opcode) {
SDNode *Parent = Value.getNode();
for (SDNode::use_iterator I = Parent->use_begin(), E = Parent->use_end();
I != E; ++I) {
if (I.getUse().get() != Value)
continue;
if (I->getOpcode() == Opcode)
return *I;
}
return 0;
}
/// This transforms the control flow intrinsics to get the branch destination as
/// last parameter, also switches branch target with BR if the need arise
SDValue SITargetLowering::LowerBRCOND(SDValue BRCOND,
SelectionDAG &DAG) const {
DebugLoc DL = BRCOND.getDebugLoc();
SDNode *Intr = BRCOND.getOperand(1).getNode();
SDValue Target = BRCOND.getOperand(2);
SDNode *BR = 0;
if (Intr->getOpcode() == ISD::SETCC) {
// As long as we negate the condition everything is fine
SDNode *SetCC = Intr;
assert(SetCC->getConstantOperandVal(1) == 1);
assert(cast<CondCodeSDNode>(SetCC->getOperand(2).getNode())->get() ==
ISD::SETNE);
Intr = SetCC->getOperand(0).getNode();
} else {
// Get the target from BR if we don't negate the condition
BR = findUser(BRCOND, ISD::BR);
Target = BR->getOperand(1);
}
assert(Intr->getOpcode() == ISD::INTRINSIC_W_CHAIN);
// Build the result and
SmallVector<EVT, 4> Res;
for (unsigned i = 1, e = Intr->getNumValues(); i != e; ++i)
Res.push_back(Intr->getValueType(i));
// operands of the new intrinsic call
SmallVector<SDValue, 4> Ops;
Ops.push_back(BRCOND.getOperand(0));
for (unsigned i = 1, e = Intr->getNumOperands(); i != e; ++i)
Ops.push_back(Intr->getOperand(i));
Ops.push_back(Target);
// build the new intrinsic call
SDNode *Result = DAG.getNode(
Res.size() > 1 ? ISD::INTRINSIC_W_CHAIN : ISD::INTRINSIC_VOID, DL,
DAG.getVTList(Res.data(), Res.size()), Ops.data(), Ops.size()).getNode();
if (BR) {
// Give the branch instruction our target
SDValue Ops[] = {
BR->getOperand(0),
BRCOND.getOperand(2)
};
DAG.MorphNodeTo(BR, ISD::BR, BR->getVTList(), Ops, 2);
}
SDValue Chain = SDValue(Result, Result->getNumValues() - 1);
// Copy the intrinsic results to registers
for (unsigned i = 1, e = Intr->getNumValues() - 1; i != e; ++i) {
SDNode *CopyToReg = findUser(SDValue(Intr, i), ISD::CopyToReg);
if (!CopyToReg)
continue;
Chain = DAG.getCopyToReg(
Chain, DL,
CopyToReg->getOperand(1),
SDValue(Result, i - 1),
SDValue());
DAG.ReplaceAllUsesWith(SDValue(CopyToReg, 0), CopyToReg->getOperand(0));
}
// Remove the old intrinsic from the chain
DAG.ReplaceAllUsesOfValueWith(
SDValue(Intr, Intr->getNumValues() - 1),
Intr->getOperand(0));
return Chain;
}
#define RSRC_DATA_FORMAT 0xf00000000000
SDValue SITargetLowering::LowerSTORE(SDValue Op, SelectionDAG &DAG) const {
StoreSDNode *StoreNode = cast<StoreSDNode>(Op);
SDValue Chain = Op.getOperand(0);
SDValue Value = Op.getOperand(1);
SDValue VirtualAddress = Op.getOperand(2);
DebugLoc DL = Op.getDebugLoc();
if (StoreNode->getAddressSpace() != AMDGPUAS::GLOBAL_ADDRESS) {
return SDValue();
}
SDValue SrcSrc = DAG.getNode(ISD::BUILD_PAIR, DL, MVT::i128,
DAG.getConstant(0, MVT::i64),
DAG.getConstant(RSRC_DATA_FORMAT, MVT::i64));
SDValue Ops[2];
Ops[0] = DAG.getNode(AMDGPUISD::BUFFER_STORE, DL, MVT::Other, Chain,
Value, SrcSrc, VirtualAddress);
Ops[1] = Chain;
return DAG.getMergeValues(Ops, 2, DL);
}
SDValue SITargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const {
SDValue LHS = Op.getOperand(0);
SDValue RHS = Op.getOperand(1);
SDValue True = Op.getOperand(2);
SDValue False = Op.getOperand(3);
SDValue CC = Op.getOperand(4);
EVT VT = Op.getValueType();
DebugLoc DL = Op.getDebugLoc();
// Possible Min/Max pattern
SDValue MinMax = LowerMinMax(Op, DAG);
if (MinMax.getNode()) {
return MinMax;
}
SDValue Cond = DAG.getNode(ISD::SETCC, DL, MVT::i1, LHS, RHS, CC);
return DAG.getNode(ISD::SELECT, DL, VT, Cond, True, False);
}
//===----------------------------------------------------------------------===//
// Custom DAG optimizations
//===----------------------------------------------------------------------===//
SDValue SITargetLowering::PerformDAGCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
SelectionDAG &DAG = DCI.DAG;
DebugLoc DL = N->getDebugLoc();
EVT VT = N->getValueType(0);
switch (N->getOpcode()) {
default: break;
case ISD::SELECT_CC: {
N->dump();
ConstantSDNode *True, *False;
// i1 selectcc(l, r, -1, 0, cc) -> i1 setcc(l, r, cc)
if ((True = dyn_cast<ConstantSDNode>(N->getOperand(2)))
&& (False = dyn_cast<ConstantSDNode>(N->getOperand(3)))
&& True->isAllOnesValue()
&& False->isNullValue()
&& VT == MVT::i1) {
return DAG.getNode(ISD::SETCC, DL, VT, N->getOperand(0),
N->getOperand(1), N->getOperand(4));
}
break;
}
case ISD::SETCC: {
SDValue Arg0 = N->getOperand(0);
SDValue Arg1 = N->getOperand(1);
SDValue CC = N->getOperand(2);
ConstantSDNode * C = NULL;
ISD::CondCode CCOp = dyn_cast<CondCodeSDNode>(CC)->get();
// i1 setcc (sext(i1), 0, setne) -> i1 setcc(i1, 0, setne)
if (VT == MVT::i1
&& Arg0.getOpcode() == ISD::SIGN_EXTEND
&& Arg0.getOperand(0).getValueType() == MVT::i1
&& (C = dyn_cast<ConstantSDNode>(Arg1))
&& C->isNullValue()
&& CCOp == ISD::SETNE) {
return SimplifySetCC(VT, Arg0.getOperand(0),
DAG.getConstant(0, MVT::i1), CCOp, true, DCI, DL);
}
break;
}
}
return SDValue();
}
/// \brief Test if RegClass is one of the VSrc classes
static bool isVSrc(unsigned RegClass) {
return AMDGPU::VSrc_32RegClassID == RegClass ||
AMDGPU::VSrc_64RegClassID == RegClass;
}
/// \brief Test if RegClass is one of the SSrc classes
static bool isSSrc(unsigned RegClass) {
return AMDGPU::SSrc_32RegClassID == RegClass ||
AMDGPU::SSrc_64RegClassID == RegClass;
}
/// \brief Analyze the possible immediate value Op
///
/// Returns -1 if it isn't an immediate, 0 if it's and inline immediate
/// and the immediate value if it's a literal immediate
int32_t SITargetLowering::analyzeImmediate(const SDNode *N) const {
union {
int32_t I;
float F;
} Imm;
if (const ConstantSDNode *Node = dyn_cast<ConstantSDNode>(N)) {
if (Node->getZExtValue() >> 32) {
return -1;
}
Imm.I = Node->getSExtValue();
} else if (const ConstantFPSDNode *Node = dyn_cast<ConstantFPSDNode>(N))
Imm.F = Node->getValueAPF().convertToFloat();
else
return -1; // It isn't an immediate
if ((Imm.I >= -16 && Imm.I <= 64) ||
Imm.F == 0.5f || Imm.F == -0.5f ||
Imm.F == 1.0f || Imm.F == -1.0f ||
Imm.F == 2.0f || Imm.F == -2.0f ||
Imm.F == 4.0f || Imm.F == -4.0f)
return 0; // It's an inline immediate
return Imm.I; // It's a literal immediate
}
/// \brief Try to fold an immediate directly into an instruction
bool SITargetLowering::foldImm(SDValue &Operand, int32_t &Immediate,
bool &ScalarSlotUsed) const {
MachineSDNode *Mov = dyn_cast<MachineSDNode>(Operand);
if (Mov == 0 || !TII->isMov(Mov->getMachineOpcode()))
return false;
const SDValue &Op = Mov->getOperand(0);
int32_t Value = analyzeImmediate(Op.getNode());
if (Value == -1) {
// Not an immediate at all
return false;
} else if (Value == 0) {
// Inline immediates can always be fold
Operand = Op;
return true;
} else if (Value == Immediate) {
// Already fold literal immediate
Operand = Op;
return true;
} else if (!ScalarSlotUsed && !Immediate) {
// Fold this literal immediate
ScalarSlotUsed = true;
Immediate = Value;
Operand = Op;
return true;
}
return false;
}
/// \brief Does "Op" fit into register class "RegClass" ?
bool SITargetLowering::fitsRegClass(SelectionDAG &DAG, SDValue &Op,
unsigned RegClass) const {
MachineRegisterInfo &MRI = DAG.getMachineFunction().getRegInfo();
SDNode *Node = Op.getNode();
const TargetRegisterClass *OpClass;
if (MachineSDNode *MN = dyn_cast<MachineSDNode>(Node)) {
const MCInstrDesc &Desc = TII->get(MN->getMachineOpcode());
int OpClassID = Desc.OpInfo[Op.getResNo()].RegClass;
if (OpClassID == -1)
OpClass = getRegClassFor(Op.getSimpleValueType());
else
OpClass = TRI->getRegClass(OpClassID);
} else if (Node->getOpcode() == ISD::CopyFromReg) {
RegisterSDNode *Reg = cast<RegisterSDNode>(Node->getOperand(1).getNode());
OpClass = MRI.getRegClass(Reg->getReg());
} else
return false;
return TRI->getRegClass(RegClass)->hasSubClassEq(OpClass);
}
/// \brief Make sure that we don't exeed the number of allowed scalars
void SITargetLowering::ensureSRegLimit(SelectionDAG &DAG, SDValue &Operand,
unsigned RegClass,
bool &ScalarSlotUsed) const {
// First map the operands register class to a destination class
if (RegClass == AMDGPU::VSrc_32RegClassID)
RegClass = AMDGPU::VReg_32RegClassID;
else if (RegClass == AMDGPU::VSrc_64RegClassID)
RegClass = AMDGPU::VReg_64RegClassID;
else
return;
// Nothing todo if they fit naturaly
if (fitsRegClass(DAG, Operand, RegClass))
return;
// If the scalar slot isn't used yet use it now
if (!ScalarSlotUsed) {
ScalarSlotUsed = true;
return;
}
// This is a conservative aproach, it is possible that we can't determine
// the correct register class and copy too often, but better save than sorry.
SDValue RC = DAG.getTargetConstant(RegClass, MVT::i32);
SDNode *Node = DAG.getMachineNode(TargetOpcode::COPY_TO_REGCLASS, DebugLoc(),
Operand.getValueType(), Operand, RC);
Operand = SDValue(Node, 0);
}
/// \brief Try to fold the Nodes operands into the Node
SDNode *SITargetLowering::foldOperands(MachineSDNode *Node,
SelectionDAG &DAG) const {
// Original encoding (either e32 or e64)
int Opcode = Node->getMachineOpcode();
const MCInstrDesc *Desc = &TII->get(Opcode);
unsigned NumDefs = Desc->getNumDefs();
unsigned NumOps = Desc->getNumOperands();
// Commuted opcode if available
int OpcodeRev = Desc->isCommutable() ? TII->commuteOpcode(Opcode) : -1;
const MCInstrDesc *DescRev = OpcodeRev == -1 ? 0 : &TII->get(OpcodeRev);
assert(!DescRev || DescRev->getNumDefs() == NumDefs);
assert(!DescRev || DescRev->getNumOperands() == NumOps);
// e64 version if available, -1 otherwise
int OpcodeE64 = AMDGPU::getVOPe64(Opcode);
const MCInstrDesc *DescE64 = OpcodeE64 == -1 ? 0 : &TII->get(OpcodeE64);
assert(!DescE64 || DescE64->getNumDefs() == NumDefs);
assert(!DescE64 || DescE64->getNumOperands() == (NumOps + 4));
int32_t Immediate = Desc->getSize() == 4 ? 0 : -1;
bool HaveVSrc = false, HaveSSrc = false;
// First figure out what we alread have in this instruction
for (unsigned i = 0, e = Node->getNumOperands(), Op = NumDefs;
i != e && Op < NumOps; ++i, ++Op) {
unsigned RegClass = Desc->OpInfo[Op].RegClass;
if (isVSrc(RegClass))
HaveVSrc = true;
else if (isSSrc(RegClass))
HaveSSrc = true;
else
continue;
int32_t Imm = analyzeImmediate(Node->getOperand(i).getNode());
if (Imm != -1 && Imm != 0) {
// Literal immediate
Immediate = Imm;
}
}
// If we neither have VSrc nor SSrc it makes no sense to continue
if (!HaveVSrc && !HaveSSrc)
return Node;
// No scalar allowed when we have both VSrc and SSrc
bool ScalarSlotUsed = HaveVSrc && HaveSSrc;
// Second go over the operands and try to fold them
std::vector<SDValue> Ops;
bool Promote2e64 = false;
for (unsigned i = 0, e = Node->getNumOperands(), Op = NumDefs;
i != e && Op < NumOps; ++i, ++Op) {
const SDValue &Operand = Node->getOperand(i);
Ops.push_back(Operand);
// Already folded immediate ?
if (isa<ConstantSDNode>(Operand.getNode()) ||
isa<ConstantFPSDNode>(Operand.getNode()))
continue;
// Is this a VSrc or SSrc operand ?
unsigned RegClass = Desc->OpInfo[Op].RegClass;
if (isVSrc(RegClass) || isSSrc(RegClass)) {
// Try to fold the immediates
if (!foldImm(Ops[i], Immediate, ScalarSlotUsed)) {
// Folding didn't worked, make sure we don't hit the SReg limit
ensureSRegLimit(DAG, Ops[i], RegClass, ScalarSlotUsed);
}
continue;
}
if (i == 1 && DescRev && fitsRegClass(DAG, Ops[0], RegClass)) {
unsigned OtherRegClass = Desc->OpInfo[NumDefs].RegClass;
assert(isVSrc(OtherRegClass) || isSSrc(OtherRegClass));
// Test if it makes sense to swap operands
if (foldImm(Ops[1], Immediate, ScalarSlotUsed) ||
(!fitsRegClass(DAG, Ops[1], RegClass) &&
fitsRegClass(DAG, Ops[1], OtherRegClass))) {
// Swap commutable operands
SDValue Tmp = Ops[1];
Ops[1] = Ops[0];
Ops[0] = Tmp;
Desc = DescRev;
DescRev = 0;
continue;
}
}
if (DescE64 && !Immediate) {
// Test if it makes sense to switch to e64 encoding
unsigned OtherRegClass = DescE64->OpInfo[Op].RegClass;
if (!isVSrc(OtherRegClass) && !isSSrc(OtherRegClass))
continue;
int32_t TmpImm = -1;
if (foldImm(Ops[i], TmpImm, ScalarSlotUsed) ||
(!fitsRegClass(DAG, Ops[i], RegClass) &&
fitsRegClass(DAG, Ops[1], OtherRegClass))) {
// Switch to e64 encoding
Immediate = -1;
Promote2e64 = true;
Desc = DescE64;
DescE64 = 0;
}
}
}
if (Promote2e64) {
// Add the modifier flags while promoting
for (unsigned i = 0; i < 4; ++i)
Ops.push_back(DAG.getTargetConstant(0, MVT::i32));
}
// Add optional chain and glue
for (unsigned i = NumOps - NumDefs, e = Node->getNumOperands(); i < e; ++i)
Ops.push_back(Node->getOperand(i));
// Create a complete new instruction
return DAG.getMachineNode(Desc->Opcode, Node->getDebugLoc(),
Node->getVTList(), Ops);
}
/// \brief Helper function for adjustWritemask
unsigned SubIdx2Lane(unsigned Idx) {
switch (Idx) {
default: return 0;
case AMDGPU::sub0: return 0;
case AMDGPU::sub1: return 1;
case AMDGPU::sub2: return 2;
case AMDGPU::sub3: return 3;
}
}
/// \brief Adjust the writemask of MIMG instructions
void SITargetLowering::adjustWritemask(MachineSDNode *&Node,
SelectionDAG &DAG) const {
SDNode *Users[4] = { };
unsigned Writemask = 0, Lane = 0;
// Try to figure out the used register components
for (SDNode::use_iterator I = Node->use_begin(), E = Node->use_end();
I != E; ++I) {
// Abort if we can't understand the usage
if (!I->isMachineOpcode() ||
I->getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG)
return;
Lane = SubIdx2Lane(I->getConstantOperandVal(1));
// Abort if we have more than one user per component
if (Users[Lane])
return;
Users[Lane] = *I;
Writemask |= 1 << Lane;
}
// Abort if all components are used
if (Writemask == 0xf)
return;
// Adjust the writemask in the node
std::vector<SDValue> Ops;
Ops.push_back(DAG.getTargetConstant(Writemask, MVT::i32));
for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i)
Ops.push_back(Node->getOperand(i));
Node = (MachineSDNode*)DAG.UpdateNodeOperands(Node, Ops.data(), Ops.size());
// If we only got one lane, replace it with a copy
if (Writemask == (1U << Lane)) {
SDValue RC = DAG.getTargetConstant(AMDGPU::VReg_32RegClassID, MVT::i32);
SDNode *Copy = DAG.getMachineNode(TargetOpcode::COPY_TO_REGCLASS,
DebugLoc(), MVT::f32,
SDValue(Node, 0), RC);
DAG.ReplaceAllUsesWith(Users[Lane], Copy);
return;
}
// Update the users of the node with the new indices
for (unsigned i = 0, Idx = AMDGPU::sub0; i < 4; ++i) {
SDNode *User = Users[i];
if (!User)
continue;
SDValue Op = DAG.getTargetConstant(Idx, MVT::i32);
DAG.UpdateNodeOperands(User, User->getOperand(0), Op);
switch (Idx) {
default: break;
case AMDGPU::sub0: Idx = AMDGPU::sub1; break;
case AMDGPU::sub1: Idx = AMDGPU::sub2; break;
case AMDGPU::sub2: Idx = AMDGPU::sub3; break;
}
}
}
/// \brief Fold the instructions after slecting them
SDNode *SITargetLowering::PostISelFolding(MachineSDNode *Node,
SelectionDAG &DAG) const {
if (AMDGPU::isMIMG(Node->getMachineOpcode()) != -1)
adjustWritemask(Node, DAG);
return foldOperands(Node, DAG);
}
/// \brief Assign the register class depending on the number of
/// bits set in the writemask
void SITargetLowering::AdjustInstrPostInstrSelection(MachineInstr *MI,
SDNode *Node) const {
if (AMDGPU::isMIMG(MI->getOpcode()) == -1)
return;
unsigned VReg = MI->getOperand(0).getReg();
unsigned Writemask = MI->getOperand(1).getImm();
unsigned BitsSet = 0;
for (unsigned i = 0; i < 4; ++i)
BitsSet += Writemask & (1 << i) ? 1 : 0;
const TargetRegisterClass *RC;
switch (BitsSet) {
default: return;
case 1: RC = &AMDGPU::VReg_32RegClass; break;
case 2: RC = &AMDGPU::VReg_64RegClass; break;
case 3: RC = &AMDGPU::VReg_96RegClass; break;
}
MachineRegisterInfo &MRI = MI->getParent()->getParent()->getRegInfo();
MRI.setRegClass(VReg, RC);
}
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