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//===- llvm/CodeGen/GlobalISel/GIMatchTableExecutor.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 GIMatchTableExecutor class.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GlobalISel/GIMatchTableExecutor.h"
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#define DEBUG_TYPE "gi-match-table-executor"
using namespace llvm;
GIMatchTableExecutor::MatcherState::MatcherState(unsigned MaxRenderers)
: Renderers(MaxRenderers) {}
GIMatchTableExecutor::GIMatchTableExecutor() = default;
bool GIMatchTableExecutor::isOperandImmEqual(const MachineOperand &MO,
int64_t Value,
const MachineRegisterInfo &MRI,
bool Splat) const {
if (MO.isReg() && MO.getReg()) {
if (auto VRegVal = getIConstantVRegValWithLookThrough(MO.getReg(), MRI))
return VRegVal->Value.getSExtValue() == Value;
if (Splat) {
if (auto VRegVal = getIConstantSplatVal(MO.getReg(), MRI))
return VRegVal->getSExtValue() == Value;
}
}
return false;
}
bool GIMatchTableExecutor::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 GIMatchTableExecutor::isObviouslySafeToFold(MachineInstr &MI,
MachineInstr &IntoMI) const {
auto IntoMIIter = IntoMI.getIterator();
// Immediate neighbours are already folded.
if (MI.getParent() == IntoMI.getParent() &&
std::next(MI.getIterator()) == IntoMIIter)
return true;
// Convergent instructions cannot be moved in the CFG.
if (MI.isConvergent() && MI.getParent() != IntoMI.getParent())
return false;
if (MI.isLoadFoldBarrier())
return false;
// If the load is simple, check instructions between MI and IntoMI
if (MI.mayLoad() && MI.getParent() == IntoMI.getParent()) {
if (MI.memoperands_empty())
return false;
auto &MMO = **(MI.memoperands_begin());
if (MMO.isAtomic() || MMO.isVolatile())
return false;
// Ensure instructions between MI and IntoMI are not affected when combined
unsigned Iter = 0;
const unsigned MaxIter = 20;
for (auto &CurrMI :
instructionsWithoutDebug(MI.getIterator(), IntoMI.getIterator())) {
if (CurrMI.isLoadFoldBarrier())
return false;
if (Iter++ == MaxIter)
return false;
}
return true;
}
return !MI.mayLoad();
}
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