103 lines · cpp
1//===- llvm/CodeGen/GlobalISel/GIMatchTableExecutor.cpp -------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9/// \file10/// This file implements the GIMatchTableExecutor class.11//12//===----------------------------------------------------------------------===//13 14#include "llvm/CodeGen/GlobalISel/GIMatchTableExecutor.h"15#include "llvm/CodeGen/GlobalISel/Utils.h"16#include "llvm/CodeGen/MachineInstr.h"17#include "llvm/CodeGen/MachineOperand.h"18#include "llvm/CodeGen/MachineRegisterInfo.h"19 20#define DEBUG_TYPE "gi-match-table-executor"21 22using namespace llvm;23 24GIMatchTableExecutor::MatcherState::MatcherState(unsigned MaxRenderers)25 : Renderers(MaxRenderers) {}26 27GIMatchTableExecutor::GIMatchTableExecutor() = default;28 29bool GIMatchTableExecutor::isOperandImmEqual(const MachineOperand &MO,30 int64_t Value,31 const MachineRegisterInfo &MRI,32 bool Splat) const {33 if (MO.isReg() && MO.getReg()) {34 if (auto VRegVal = getIConstantVRegValWithLookThrough(MO.getReg(), MRI))35 return VRegVal->Value.getSExtValue() == Value;36 37 if (Splat) {38 if (auto VRegVal = getIConstantSplatVal(MO.getReg(), MRI))39 return VRegVal->getSExtValue() == Value;40 }41 }42 return false;43}44 45bool GIMatchTableExecutor::isBaseWithConstantOffset(46 const MachineOperand &Root, const MachineRegisterInfo &MRI) const {47 if (!Root.isReg())48 return false;49 50 MachineInstr *RootI = MRI.getVRegDef(Root.getReg());51 if (RootI->getOpcode() != TargetOpcode::G_PTR_ADD)52 return false;53 54 MachineOperand &RHS = RootI->getOperand(2);55 MachineInstr *RHSI = MRI.getVRegDef(RHS.getReg());56 if (RHSI->getOpcode() != TargetOpcode::G_CONSTANT)57 return false;58 59 return true;60}61 62bool GIMatchTableExecutor::isObviouslySafeToFold(MachineInstr &MI,63 MachineInstr &IntoMI) const {64 auto IntoMIIter = IntoMI.getIterator();65 66 // Immediate neighbours are already folded.67 if (MI.getParent() == IntoMI.getParent() &&68 std::next(MI.getIterator()) == IntoMIIter)69 return true;70 71 // Convergent instructions cannot be moved in the CFG.72 if (MI.isConvergent() && MI.getParent() != IntoMI.getParent())73 return false;74 75 if (MI.isLoadFoldBarrier())76 return false;77 78 // If the load is simple, check instructions between MI and IntoMI79 if (MI.mayLoad() && MI.getParent() == IntoMI.getParent()) {80 if (MI.memoperands_empty())81 return false;82 auto &MMO = **(MI.memoperands_begin());83 if (MMO.isAtomic() || MMO.isVolatile())84 return false;85 86 // Ensure instructions between MI and IntoMI are not affected when combined87 unsigned Iter = 0;88 const unsigned MaxIter = 20;89 for (auto &CurrMI :90 instructionsWithoutDebug(MI.getIterator(), IntoMI.getIterator())) {91 if (CurrMI.isLoadFoldBarrier())92 return false;93 94 if (Iter++ == MaxIter)95 return false;96 }97 98 return true;99 }100 101 return !MI.mayLoad();102}103