path: root/lib/Target/PowerPC/PPCISelDAGToDAG.cpp

//===-- PPCISelDAGToDAG.cpp - PPC --pattern matching inst selector --------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a pattern matching instruction selector for PowerPC,
// converting from a legalized dag to a PPC dag.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "ppc-codegen"
#include "PPC.h"
#include "PPCPredicates.h"
#include "PPCTargetMachine.h"
#include "PPCISelLowering.h"
#include "PPCHazardRecognizers.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Constants.h"
#include "llvm/GlobalValue.h"
#include "llvm/Intrinsics.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Compiler.h"
#include <queue>
#include <set>
using namespace llvm;

namespace {
  //===--------------------------------------------------------------------===//
  /// PPCDAGToDAGISel - PPC specific code to select PPC machine
  /// instructions for SelectionDAG operations.
  ///
  class VISIBILITY_HIDDEN PPCDAGToDAGISel : public SelectionDAGISel {
    PPCTargetMachine &TM;
    PPCTargetLowering PPCLowering;
    const PPCSubtarget &PPCSubTarget;
    unsigned GlobalBaseReg;
  public:
    PPCDAGToDAGISel(PPCTargetMachine &tm)
      : SelectionDAGISel(PPCLowering), TM(tm),
        PPCLowering(*TM.getTargetLowering()),
        PPCSubTarget(*TM.getSubtargetImpl()) {}
    
    virtual bool runOnFunction(Function &Fn) {
      // Make sure we re-emit a set of the global base reg if necessary
      GlobalBaseReg = 0;
      SelectionDAGISel::runOnFunction(Fn);
      
      InsertVRSaveCode(Fn);
      return true;
    }
   
    /// getI32Imm - Return a target constant with the specified value, of type
    /// i32.
    inline SDOperand getI32Imm(unsigned Imm) {
      return CurDAG->getTargetConstant(Imm, MVT::i32);
    }

    /// getI64Imm - Return a target constant with the specified value, of type
    /// i64.
    inline SDOperand getI64Imm(uint64_t Imm) {
      return CurDAG->getTargetConstant(Imm, MVT::i64);
    }
    
    /// getSmallIPtrImm - Return a target constant of pointer type.
    inline SDOperand getSmallIPtrImm(unsigned Imm) {
      return CurDAG->getTargetConstant(Imm, PPCLowering.getPointerTy());
    }
    
    /// isRunOfOnes - Returns true iff Val consists of one contiguous run of 1s 
    /// with any number of 0s on either side.  The 1s are allowed to wrap from
    /// LSB to MSB, so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs.
    /// 0x0F0F0000 is not, since all 1s are not contiguous.
    static bool isRunOfOnes(unsigned Val, unsigned &MB, unsigned &ME);


    /// isRotateAndMask - Returns true if Mask and Shift can be folded into a
    /// rotate and mask opcode and mask operation.
    static bool isRotateAndMask(SDNode *N, unsigned Mask, bool IsShiftMask,
                                unsigned &SH, unsigned &MB, unsigned &ME);
    
    /// getGlobalBaseReg - insert code into the entry mbb to materialize the PIC
    /// base register.  Return the virtual register that holds this value.
    SDNode *getGlobalBaseReg();
    
    // Select - Convert the specified operand from a target-independent to a
    // target-specific node if it hasn't already been changed.
    SDNode *Select(SDOperand Op);
    
    SDNode *SelectBitfieldInsert(SDNode *N);

    /// SelectCC - Select a comparison of the specified values with the
    /// specified condition code, returning the CR# of the expression.
    SDOperand SelectCC(SDOperand LHS, SDOperand RHS, ISD::CondCode CC);

    /// SelectAddrImm - Returns true if the address N can be represented by
    /// a base register plus a signed 16-bit displacement [r+imm].
    bool SelectAddrImm(SDOperand Op, SDOperand N, SDOperand &Disp,
                       SDOperand &Base) {
      return PPCLowering.SelectAddressRegImm(N, Disp, Base, *CurDAG);
    }
    
    /// SelectAddrImmOffs - Return true if the operand is valid f