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f4145ddf5b
Before merging two instructions together, GISel does some sanity checks that the folding is legal. However that check was missing that the source of the pattern may be convergent. When the destination location is in a different basic block, the folding is invalid. Differential Revision: https://reviews.llvm.org/D128539
69 lines
2.3 KiB
C++
69 lines
2.3 KiB
C++
//===- llvm/CodeGen/GlobalISel/InstructionSelector.cpp --------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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/// \file
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/// This file implements the InstructionSelector class.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
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#include "llvm/CodeGen/GlobalISel/Utils.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineOperand.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#define DEBUG_TYPE "instructionselector"
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using namespace llvm;
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InstructionSelector::MatcherState::MatcherState(unsigned MaxRenderers)
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: Renderers(MaxRenderers) {}
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InstructionSelector::InstructionSelector() = default;
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bool InstructionSelector::isOperandImmEqual(
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const MachineOperand &MO, int64_t Value,
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const MachineRegisterInfo &MRI) const {
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if (MO.isReg() && MO.getReg())
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if (auto VRegVal = getIConstantVRegValWithLookThrough(MO.getReg(), MRI))
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return VRegVal->Value.getSExtValue() == Value;
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return false;
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}
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bool InstructionSelector::isBaseWithConstantOffset(
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const MachineOperand &Root, const MachineRegisterInfo &MRI) const {
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if (!Root.isReg())
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return false;
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MachineInstr *RootI = MRI.getVRegDef(Root.getReg());
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if (RootI->getOpcode() != TargetOpcode::G_PTR_ADD)
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return false;
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MachineOperand &RHS = RootI->getOperand(2);
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MachineInstr *RHSI = MRI.getVRegDef(RHS.getReg());
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if (RHSI->getOpcode() != TargetOpcode::G_CONSTANT)
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return false;
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return true;
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}
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bool InstructionSelector::isObviouslySafeToFold(MachineInstr &MI,
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MachineInstr &IntoMI) const {
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// Immediate neighbours are already folded.
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if (MI.getParent() == IntoMI.getParent() &&
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std::next(MI.getIterator()) == IntoMI.getIterator())
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return true;
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// Convergent instructions cannot be moved in the CFG.
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if (MI.isConvergent() && MI.getParent() != IntoMI.getParent())
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return false;
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return !MI.mayLoadOrStore() && !MI.mayRaiseFPException() &&
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!MI.hasUnmodeledSideEffects() && MI.implicit_operands().empty();
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}
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