1 //===- llvm/CodeGen/GlobalISel/InstructionSelector.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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 /// \file 10 /// This file implements the InstructionSelector class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/CodeGen/GlobalISel/InstructionSelector.h" 15 #include "llvm/CodeGen/GlobalISel/Utils.h" 16 #include "llvm/CodeGen/MachineBasicBlock.h" 17 #include "llvm/CodeGen/MachineFunction.h" 18 #include "llvm/CodeGen/MachineInstr.h" 19 #include "llvm/CodeGen/MachineOperand.h" 20 #include "llvm/CodeGen/MachineRegisterInfo.h" 21 #include "llvm/CodeGen/TargetRegisterInfo.h" 22 #include "llvm/MC/MCInstrDesc.h" 23 #include "llvm/Support/Debug.h" 24 #include "llvm/Support/raw_ostream.h" 25 #include <cassert> 26 27 #define DEBUG_TYPE "instructionselector" 28 29 using namespace llvm; 30 31 InstructionSelector::MatcherState::MatcherState(unsigned MaxRenderers) 32 : Renderers(MaxRenderers), MIs() {} 33 34 InstructionSelector::InstructionSelector() = default; 35 36 bool InstructionSelector::isOperandImmEqual( 37 const MachineOperand &MO, int64_t Value, 38 const MachineRegisterInfo &MRI) const { 39 if (MO.isReg() && MO.getReg()) 40 if (auto VRegVal = getConstantVRegValWithLookThrough(MO.getReg(), MRI)) 41 return VRegVal->Value.getSExtValue() == Value; 42 return false; 43 } 44 45 bool InstructionSelector::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 62 bool InstructionSelector::isObviouslySafeToFold(MachineInstr &MI, 63 MachineInstr &IntoMI) const { 64 // Immediate neighbours are already folded. 65 if (MI.getParent() == IntoMI.getParent() && 66 std::next(MI.getIterator()) == IntoMI.getIterator()) 67 return true; 68 69 return !MI.mayLoadOrStore() && !MI.mayRaiseFPException() && 70 !MI.hasUnmodeledSideEffects() && MI.implicit_operands().empty(); 71 } 72