path: root/lib/VMCore/ConstantFold.cpp

//===- ConstantFolding.cpp - LLVM constant folder -------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements folding of constants for LLVM.  This implements the
// (internal) ConstantFolding.h interface, which is used by the
// ConstantExpr::get* methods to automatically fold constants when possible.
//
// The current constant folding implementation is implemented in two pieces: the
// template-based folder for simple primitive constants like ConstantInt, and
// the special case hackery that we use to symbolically evaluate expressions
// that use ConstantExprs.
//
//===----------------------------------------------------------------------===//

#include "ConstantFolding.h"
#include "llvm/Constants.h"
#include "llvm/Instructions.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include <limits>
#include <cmath>
using namespace llvm;

namespace {
  struct ConstRules {
    ConstRules() {}
    virtual ~ConstRules() {}

    // Binary Operators...
    virtual Constant *add(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *sub(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *mul(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *div(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *rem(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *op_and(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *op_or (const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *op_xor(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *shl(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *shr(const Constant *V1, const Constant *V2) const = 0;
    virtual Constant *lessthan(const Constant *V1, const Constant *V2) const =0;
    virtual Constant *equalto(const Constant *V1, const Constant *V2) const = 0;

    // Casting operators.
    virtual Constant *castToBool  (const Constant *V) const = 0;
    virtual Constant *castToSByte (const Constant *V) const = 0;
    virtual Constant *castToUByte (const Constant *V) const = 0;
    virtual Constant *castToShort (const Constant *V) const = 0;
    virtual Constant *castToUShort(const Constant *V) const = 0;
    virtual Constant *castToInt   (const Constant *V) const