1 //===- llvm/CodeGen/GlobalISel/InstructionSelector.cpp -----------*- C++ -*-==// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 /// \file 10 /// This file implements the InstructionSelector class. 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/CodeGen/GlobalISel/InstructionSelector.h" 14 #include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h" 15 #include "llvm/CodeGen/MachineInstr.h" 16 #include "llvm/Target/TargetInstrInfo.h" 17 #include "llvm/Target/TargetRegisterInfo.h" 18 19 #define DEBUG_TYPE "instructionselector" 20 21 using namespace llvm; 22 23 InstructionSelector::InstructionSelector() {} 24 25 bool InstructionSelector::constrainSelectedInstRegOperands( 26 MachineInstr &I, const TargetInstrInfo &TII, const TargetRegisterInfo &TRI, 27 const RegisterBankInfo &RBI) const { 28 MachineBasicBlock &MBB = *I.getParent(); 29 MachineFunction &MF = *MBB.getParent(); 30 MachineRegisterInfo &MRI = MF.getRegInfo(); 31 32 for (unsigned OpI = 0, OpE = I.getNumExplicitOperands(); OpI != OpE; ++OpI) { 33 MachineOperand &MO = I.getOperand(OpI); 34 35 // There's nothing to be done on non-register operands. 36 if (!MO.isReg()) 37 continue; 38 39 DEBUG(dbgs() << "Converting operand: " << MO << '\n'); 40 assert(MO.isReg() && "Unsupported non-reg operand"); 41 42 // Physical registers don't need to be constrained. 43 if (TRI.isPhysicalRegister(MO.getReg())) 44 continue; 45 46 const TargetRegisterClass *RC = TII.getRegClass(I.getDesc(), OpI, &TRI, MF); 47 assert(RC && "Selected inst should have regclass operand"); 48 49 // If the operand is a vreg, we should constrain its regclass, and only 50 // insert COPYs if that's impossible. 51 // If the operand is a physreg, we only insert COPYs if the register class 52 // doesn't contain the register. 53 if (RBI.constrainGenericRegister(MO.getReg(), *RC, MRI)) 54 continue; 55 56 DEBUG(dbgs() << "Constraining with COPYs isn't implemented yet"); 57 return false; 58 } 59 return true; 60 } 61