InstructionSelector.cpp
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//===- llvm/CodeGen/GlobalISel/InstructionSelector.cpp --------------------===//
//
// 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
/// This file implements the InstructionSelector class.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#define DEBUG_TYPE "instructionselector"
using namespace llvm;
InstructionSelector::MatcherState::MatcherState(unsigned MaxRenderers)
: Renderers(MaxRenderers), MIs() {}
InstructionSelector::InstructionSelector() = default;
bool InstructionSelector::constrainOperandRegToRegClass(
MachineInstr &I, unsigned OpIdx, const TargetRegisterClass &RC,
const TargetInstrInfo &TII, const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) const {
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
return constrainOperandRegClass(MF, TRI, MRI, TII, RBI, I, RC,
I.getOperand(OpIdx));
}
bool InstructionSelector::isOperandImmEqual(
const MachineOperand &MO, int64_t Value,
const MachineRegisterInfo &MRI) const {
if (MO.isReg() && MO.getReg())
if (auto VRegVal = getConstantVRegValWithLookThrough(MO.getReg(), MRI))
return VRegVal->Value == Value;
return false;
}
bool InstructionSelector::isBaseWithConstantOffset(
const MachineOperand &Root, const MachineRegisterInfo &MRI) const {
if (!Root.isReg())
return false;
MachineInstr *RootI = MRI.getVRegDef(Root.getReg());
if (RootI->getOpcode() != TargetOpcode::G_PTR_ADD)
return false;
MachineOperand &RHS = RootI->getOperand(2);
MachineInstr *RHSI = MRI.getVRegDef(RHS.getReg());
if (RHSI->getOpcode() != TargetOpcode::G_CONSTANT)
return false;
return true;
}
bool InstructionSelector::isObviouslySafeToFold(MachineInstr &MI,
MachineInstr &IntoMI) const {
// Immediate neighbours are already folded.
if (MI.getParent() == IntoMI.getParent() &&
std::next(MI.getIterator()) == IntoMI.getIterator())
return true;
return !MI.mayLoadOrStore() && !MI.mayRaiseFPException() &&
!MI.hasUnmodeledSideEffects() && MI.implicit_operands().empty();
}