path: root/lib/Target/MSP430/MSP430ISelLowering.cpp

//===-- MSP430ISelLowering.cpp - MSP430 DAG Lowering Implementation  ------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the MSP430TargetLowering class.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "msp430-lower"

#include "MSP430ISelLowering.h"
#include "MSP430.h"
#include "MSP430MachineFunctionInfo.h"
#include "MSP430Subtarget.h"
#include "MSP430TargetMachine.h"
#include "llvm/CallingConv.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalAlias.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Intrinsics.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;

typedef enum {
  NoHWMult,
  HWMultIntr,
  HWMultNoIntr
} HWMultUseMode;

static cl::opt<HWMultUseMode>
HWMultMode("msp430-hwmult-mode",
           cl::desc("Hardware multiplier use mode"),
           cl::init(HWMultNoIntr),
           cl::values(
             clEnumValN(NoHWMult, "no",
                "Do not use hardware multiplier"),
             clEnumValN(HWMultIntr, "interrupts",
                "Assume hardware multiplier can be used inside interrupts"),
             clEnumValN(HWMultNoIntr, "use",
                "Assume hardware multiplier cannot be used inside interrupts"),
             clEnumValEnd));

MSP430TargetLowering::MSP430TargetLowering(MSP430TargetMachine &tm) :
  TargetLowering(tm, new TargetLoweringObjectFileELF()),
  Subtarget(*tm.getSubtargetImpl()) {

  TD = getDataLayout();

  // Set up the register classes.
  addRegisterClass(MVT::i8,  &MSP430::GR8RegClass);
  addRegisterClass(MVT::i16, &MSP430::GR16RegClass);

  // Compute derived properties from the register classes
  computeRegisterProperties();

  // Provide all sorts of operation actions

  // Division is expensive
  setIntDivIsCheap(false);

  setStackPointerRegisterToSaveRestore(MSP430::SPW);
  setBooleanContents(ZeroOrOneBooleanContent);
  setBooleanVectorContents(ZeroOrOneBooleanContent); // FIXME: Is this correct?

  // We have post-incremented loads / stores.
  setIndexedLoadAction(ISD::POST_INC, MVT::i8, Legal);
  setIndexedLoadAction(ISD::POST_INC, MVT::i16, Legal);

  setLoadExtAction(ISD::EXTLOAD,  MVT::i1,  Promote);
  setLoadExtAction(ISD::SEXTLOAD, MVT::i1,  Promote);
  setLoadExtAction(ISD::ZEXTLOAD, MVT::i1,  Promote);
  setLoadExtAction(ISD::SEXTLOAD, MVT::i8,  Expand);
  setLoadExtAction(ISD::SEXTLOAD, MVT::i16, Expand);

  // We don't have any truncstores
  setTruncStoreAction(MVT::i16, MVT::i8, Expand);

  setOperationAction(ISD::SRA,              MVT::i8,    Custom);
  setOperationAction(ISD::SHL,              MVT::i8,    Custom);
  setOperationAction(ISD