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//===-- R600ISelDAGToDAG.cpp - A dag to dag inst selector for R600 --------===//
//
// 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
//
//==-----------------------------------------------------------------------===//
//
/// \file
/// Defines an instruction selector for the R600 subtarget.
//
//===----------------------------------------------------------------------===//
#include "AMDGPU.h"
#include "AMDGPUISelDAGToDAG.h"
#include "MCTargetDesc/R600MCTargetDesc.h"
#include "R600.h"
#include "R600Subtarget.h"
#include "llvm/Analysis/ValueTracking.h"
class R600DAGToDAGISel : public AMDGPUDAGToDAGISel {
const R600Subtarget *Subtarget;
bool isConstantLoad(const MemSDNode *N, int cbID) const;
bool SelectGlobalValueConstantOffset(SDValue Addr, SDValue &IntPtr);
bool SelectGlobalValueVariableOffset(SDValue Addr, SDValue &BaseReg,
SDValue &Offset);
public:
explicit R600DAGToDAGISel(TargetMachine *TM, CodeGenOpt::Level OptLevel)
: AMDGPUDAGToDAGISel(TM, OptLevel) {}
void Select(SDNode *N) override;
bool SelectADDRIndirect(SDValue Addr, SDValue &Base,
SDValue &Offset) override;
bool SelectADDRVTX_READ(SDValue Addr, SDValue &Base,
SDValue &Offset) override;
bool runOnMachineFunction(MachineFunction &MF) override;
void PreprocessISelDAG() override {}
protected:
// Include the pieces autogenerated from the target description.
#include "R600GenDAGISel.inc"
};
bool R600DAGToDAGISel::runOnMachineFunction(MachineFunction &MF) {
Subtarget = &MF.getSubtarget<R600Subtarget>();
return SelectionDAGISel::runOnMachineFunction(MF);
}
bool R600DAGToDAGISel::isConstantLoad(const MemSDNode *N, int CbId) const {
if (!N->readMem())
return false;
if (CbId == -1)
return N->getAddressSpace() == AMDGPUAS::CONSTANT_ADDRESS ||
N->getAddressSpace() == AMDGPUAS::CONSTANT_ADDRESS_32BIT;
return N->getAddressSpace() == AMDGPUAS::CONSTANT_BUFFER_0 + CbId;
}
bool R600DAGToDAGISel::SelectGlobalValueConstantOffset(SDValue Addr,
SDValue &IntPtr) {
if (ConstantSDNode *Cst = dyn_cast<ConstantSDNode>(Addr)) {
IntPtr =
CurDAG->getIntPtrConstant(Cst->getZExtValue() / 4, SDLoc(Addr), true);
return true;
}
return false;
}
bool R600DAGToDAGISel::SelectGlobalValueVariableOffset(SDValue Addr,
SDValue &BaseReg,
SDValue &Offset) {
if (!isa<ConstantSDNode>(Addr)) {
BaseReg = Addr;
Offset = CurDAG->getIntPtrConstant(0, SDLoc(Addr), true);
return true;
}
return false;
}
void R600DAGToDAGISel::Select(SDNode *N) {
unsigned int Opc = N->getOpcode();
if (N->isMachineOpcode()) {
N->setNodeId(-1);
return; // Already selected.
}
switch (Opc) {
default:
break;
case AMDGPUISD::BUILD_VERTICAL_VECTOR:
case ISD::SCALAR_TO_VECTOR:
case ISD::BUILD_VECTOR: {
EVT VT = N->getValueType(0);
unsigned NumVectorElts = VT.getVectorNumElements();
unsigned RegClassID;
// BUILD_VECTOR was lowered into an IMPLICIT_DEF + 4 INSERT_SUBREG
// that adds a 128 bits reg copy when going through TwoAddressInstructions
// pass. We want to avoid 128 bits copies as much as possible because they
// can't be bundled by our scheduler.
switch (NumVectorElts) {
case 2:
RegClassID = R600::R600_Reg64RegClassID;
break;
case 4:
if (Opc == AMDGPUISD::BUILD_VERTICAL_VECTOR)
RegClassID = R600::R600_Reg128VerticalRegClassID;
else
RegClassID = R600::R600_Reg128RegClassID;
break;
default:
llvm_unreachable("Do not know how to lower this BUILD_VECTOR");
}
SelectBuildVector(N, RegClassID);
return;
}
}
SelectCode(N);
}
bool R600DAGToDAGISel::SelectADDRIndirect(SDValue Addr, SDValue &Base,
SDValue &Offset) {
ConstantSDNode *C;
SDLoc DL(Addr);
if ((C = dyn_cast<ConstantSDNode>(Addr))) {
Base = CurDAG->getRegister(R600::INDIRECT_BASE_ADDR, MVT::i32);
Offset = CurDAG->getTargetConstant(C->getZExtValue(), DL, MVT::i32);
} else if ((Addr.getOpcode() == AMDGPUISD::DWORDADDR) &&
(C = dyn_cast<ConstantSDNode>(Addr.getOperand(0)))) {
Base = CurDAG->getRegister(R600::INDIRECT_BASE_ADDR, MVT::i32);
Offset = CurDAG->getTargetConstant(C->getZExtValue(), DL, MVT::i32);
} else if ((Addr.getOpcode() == ISD::ADD || Addr.getOpcode() == ISD::OR) &&
(C = dyn_cast<ConstantSDNode>(Addr.getOperand(1)))) {
Base = Addr.getOperand(0);
Offset = CurDAG->getTargetConstant(C->getZExtValue(), DL, MVT::i32);
} else {
Base = Addr;
Offset = CurDAG->getTargetConstant(0, DL, MVT::i32);
}
return true;
}
bool R600DAGToDAGISel::SelectADDRVTX_READ(SDValue Addr, SDValue &Base,
SDValue &Offset) {
ConstantSDNode *IMMOffset;
if (Addr.getOpcode() == ISD::ADD &&
(IMMOffset = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) &&
isInt<16>(IMMOffset->getZExtValue())) {
Base = Addr.getOperand(0);
Offset = CurDAG->getTargetConstant(IMMOffset->getZExtValue(), SDLoc(Addr),
MVT::i32);
return true;
// If the pointer address is constant, we can move it to the offset field.
} else if ((IMMOffset = dyn_cast<ConstantSDNode>(Addr)) &&
isInt<16>(IMMOffset->getZExtValue())) {
Base = CurDAG->getCopyFromReg(CurDAG->getEntryNode(),
SDLoc(CurDAG->getEntryNode()), R600::ZERO,
MVT::i32);
Offset = CurDAG->getTargetConstant(IMMOffset->getZExtValue(), SDLoc(Addr),
MVT::i32);
return true;
}
// Default case, no offset
Base = Addr;
Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), MVT::i32);
return true;
}
/// This pass converts a legalized DAG into a R600-specific
// DAG, ready for instruction scheduling.
FunctionPass *llvm::createR600ISelDag(TargetMachine *TM,
CodeGenOpt::Level OptLevel) {
return new R600DAGToDAGISel(TM, OptLevel);
}