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remove a dead file 

llvm-svn: 24085
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Chris Lattner 2005-10-29 04:43:38 +00:00
parent 29b04e1021
commit 21193ac3c0
1 changed files with 0 additions and 355 deletions
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llvm/lib/Analysis/Expressions.cpp
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//===- Expressions.cpp - Expression Analysis Utilities --------------------===//
//
// 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 defines a package of expression analysis utilties:
//
// ClassifyExpression: Analyze an expression to determine the complexity of the
// expression, and which other variables it depends on.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/Expressions.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Type.h"
#include <iostream>
using namespace llvm;
ExprType::ExprType(Value *Val) {
if (Val)
if (ConstantInt *CPI = dyn_cast<ConstantInt>(Val)) {
Offset = CPI;
Var = 0;
ExprTy = Constant;
Scale = 0;
return;
}
Var = Val; Offset = 0;
ExprTy = Var ? Linear : Constant;
Scale = 0;
}
ExprType::ExprType(const ConstantInt *scale, Value *var,
const ConstantInt *offset) {
Scale = var ? scale : 0; Var = var; Offset = offset;
ExprTy = Scale ? ScaledLinear : (Var ? Linear : Constant);
if (Scale && Scale->isNullValue()) { // Simplify 0*Var + const
Scale = 0; Var = 0;
ExprTy = Constant;
}
}
const Type *ExprType::getExprType(const Type *Default) const {
if (Offset) return Offset->getType();
if (Scale) return Scale->getType();
return Var ? Var->getType() : Default;
}
namespace {
class DefVal {
const ConstantInt * const Val;
const Type * const Ty;
protected:
inline DefVal(const ConstantInt *val, const Type *ty) : Val(val), Ty(ty) {}
public:
inline const Type *getType() const { return Ty; }
inline const ConstantInt *getVal() const { return Val; }
inline operator const ConstantInt * () const { return Val; }
inline const ConstantInt *operator->() const { return Val; }
};
struct DefZero : public DefVal {
inline DefZero(const ConstantInt *val, const Type *ty) : DefVal(val, ty) {}
inline DefZero(const ConstantInt *val) : DefVal(val, val->getType()) {}
};
struct DefOne : public DefVal {
inline DefOne(const ConstantInt *val, const Type *ty) : DefVal(val, ty) {}
};
}
// getUnsignedConstant - Return a constant value of the specified type. If the
// constant value is not valid for the specified type, return null. This cannot
// happen for values in the range of 0 to 127.
//
static ConstantInt *getUnsignedConstant(uint64_t V, const Type *Ty) {
if (isa<PointerType>(Ty)) Ty = Type::ULongTy;
if (Ty->isSigned()) {
// If this value is not a valid unsigned value for this type, return null!
if (V > 127 && ((int64_t)V < 0 ||
!ConstantSInt::isValueValidForType(Ty, (int64_t)V)))
return 0;
return ConstantSInt::get(Ty, V);
} else {
// If this value is not a valid unsigned value for this type, return null!
if (V > 255 && !ConstantUInt::isValueValidForType(Ty, V))
return 0;
return ConstantUInt::get(Ty, V);
}
}
// Add - Helper function to make later code simpler. Basically it just adds
// the two constants together, inserts the result into the constant pool, and
// returns it. Of course life is not simple, and this is no exception. Factors
// that complicate matters:
// 1. Either argument may be null. If this is the case, the null argument is
// treated as either 0 (if DefOne = false) or 1 (if DefOne = true)
// 2. Types get in the way. We want to do arithmetic operations without
// regard for the underlying types. It is assumed that the constants are
// integral constants. The new value takes the type of the left argument.
// 3. If DefOne is true, a null return value indicates a value of 1, if DefOne
// is false, a null return value indicates a value of 0.
//
static const ConstantInt *Add(const ConstantInt *Arg1,
const ConstantInt *Arg2, bool DefOne) {
assert(Arg1 && Arg2 && "No null arguments should exist now!");
assert(Arg1->getType() == Arg2->getType() && "Types must be compatible!");
// Actually perform the computation now!
Constant *Result = ConstantExpr::get(Instruction::Add, (Constant*)Arg1,
(Constant*)Arg2);
ConstantInt *ResultI = cast<ConstantInt>(Result);
// Check to see if the result is one of the special cases that we want to
// recognize...
if (ResultI->equalsInt(DefOne ? 1 : 0))
return 0; // Yes it is, simply return null.
return ResultI;
}
static inline const ConstantInt *operator+(const DefZero &L, const DefZero &R) {
if (L == 0) return R;
if (R == 0) return L;
return Add(L, R, false);
}
static inline const ConstantInt *operator+(const DefOne &L, const DefOne &R) {
if (L == 0) {
if (R == 0)
return getUnsignedConstant(2, L.getType());
else
return Add(getUnsignedConstant(1, L.getType()), R, true);
} else if (R == 0) {
return Add(L, getUnsignedConstant(1, L.getType()), true);
}
return Add(L, R, true);
}
// Mul - Helper function to make later code simpler. Basically it just
// multiplies the two constants together, inserts the result into the constant
// pool, and returns it. Of course life is not simple, and this is no
// exception. Factors that complicate matters:
// 1. Either argument may be null. If this is the case, the null argument is
// treated as either 0 (if DefOne = false) or 1 (if DefOne = true)
// 2. Types get in the way. We want to do arithmetic operations without
// regard for the underlying types. It is assumed that the constants are
// integral constants.
// 3. If DefOne is true, a null return value indicates a value of 1, if DefOne
// is false, a null return value indicates a value of 0.
//
static inline const ConstantInt *Mul(const ConstantInt *Arg1,
const ConstantInt *Arg2, bool DefOne) {
assert(Arg1 && Arg2 && "No null arguments should exist now!");
assert(Arg1->getType() == Arg2->getType() && "Types must be compatible!");
// Actually perform the computation now!
Constant *Result = ConstantExpr::get(Instruction::Mul, (Constant*)Arg1,
(Constant*)Arg2);
assert(Result && Result->getType() == Arg1->getType() &&
"Couldn't perform multiplication!");
ConstantInt *ResultI = cast<ConstantInt>(Result);
// Check to see if the result is one of the special cases that we want to
// recognize...
if (ResultI->equalsInt(DefOne ? 1 : 0))
return 0; // Yes it is, simply return null.
return ResultI;
}
namespace {
inline const ConstantInt *operator*(const DefZero &L, const DefZero &R) {
if (L == 0 || R == 0) return 0;
return Mul(L, R, false);
}
inline const ConstantInt *operator*(const DefOne &L, const DefZero &R) {
if (R == 0) return getUnsignedConstant(0, L.getType());
if (L == 0) return R->equalsInt(1) ? 0 : R.getVal();
return Mul(L, R, true);
}
inline const ConstantInt *operator*(const DefZero &L, const DefOne &R) {
if (L == 0 || R == 0) return L.getVal();
return Mul(R, L, false);
}
}
// handleAddition - Add two expressions together, creating a new expression that
// represents the composite of the two...
//
static ExprType handleAddition(ExprType Left, ExprType Right, Value *V) {
const Type *Ty = V->getType();
if (Left.ExprTy > Right.ExprTy)
std::swap(Left, Right); // Make left be simpler than right
switch (Left.ExprTy) {
case ExprType::Constant:
return ExprType(Right.Scale, Right.Var,
DefZero(Right.Offset, Ty) + DefZero(Left.Offset, Ty));
case ExprType::Linear: // RHS side must be linear or scaled
case ExprType::ScaledLinear: // RHS must be scaled
if (Left.Var != Right.Var) // Are they the same variables?
return V; // if not, we don't know anything!
return ExprType(DefOne(Left.Scale , Ty) + DefOne(Right.Scale , Ty),
Right.Var,
DefZero(Left.Offset, Ty) + DefZero(Right.Offset, Ty));
default:
assert(0 && "Dont' know how to handle this case!");
return ExprType();
}
}
// negate - Negate the value of the specified expression...
//
static inline ExprType negate(const ExprType &E, Value *V) {
const Type *Ty = V->getType();
ConstantInt *Zero = getUnsignedConstant(0, Ty);
ConstantInt *One = getUnsignedConstant(1, Ty);
ConstantInt *NegOne = cast<ConstantInt>(ConstantExpr::get(Instruction::Sub,
Zero, One));
if (NegOne == 0) return V; // Couldn't subtract values...
return ExprType(DefOne (E.Scale , Ty) * NegOne, E.Var,
DefZero(E.Offset, Ty) * NegOne);
}
// ClassifyExpr: Analyze an expression to determine the complexity of the
// expression, and which other values it depends on.
//
// Note that this analysis cannot get into infinite loops because it treats PHI
// nodes as being an unknown linear expression.
//
ExprType llvm::ClassifyExpr(Value *Expr) {
assert(Expr != 0 && "Can't classify a null expression!");
if (Expr->getType()->isFloatingPoint())
return Expr; // FIXME: Can't handle FP expressions
if (Constant *C = dyn_cast<Constant>(Expr)) {
if (ConstantInt *CPI = dyn_cast<ConstantInt>(cast<Constant>(Expr)))
// It's an integral constant!
return ExprType(CPI->isNullValue() ? 0 : CPI);
return Expr;
} else if (!isa<Instruction>(Expr)) {
return Expr;
}
Instruction *I = cast<Instruction>(Expr);
const Type *Ty = I->getType();
switch (I->getOpcode()) { // Handle each instruction type separately
case Instruction::Add: {
ExprType Left (ClassifyExpr(I->getOperand(0)));
ExprType Right(ClassifyExpr(I->getOperand(1)));
return handleAddition(Left, Right, I);
} // end case Instruction::Add
case Instruction::Sub: {
ExprType Left (ClassifyExpr(I->getOperand(0)));
ExprType Right(ClassifyExpr(I->getOperand(1)));
ExprType RightNeg = negate(Right, I);
if (RightNeg.Var == I && !RightNeg.Offset && !RightNeg.Scale)
return I; // Could not negate value...
return handleAddition(Left, RightNeg, I);
} // end case Instruction::Sub
case Instruction::Shl: {
ExprType Right(ClassifyExpr(I->getOperand(1)));
if (Right.ExprTy != ExprType::Constant) break;
ExprType Left(ClassifyExpr(I->getOperand(0)));
if (Right.Offset == 0) return Left; // shl x, 0 = x
assert(Right.Offset->getType() == Type::UByteTy &&
"Shift amount must always be a unsigned byte!");
uint64_t ShiftAmount = cast<ConstantUInt>(Right.Offset)->getValue();
ConstantInt *Multiplier = getUnsignedConstant(1ULL << ShiftAmount, Ty);
// We don't know how to classify it if they are shifting by more than what
// is reasonable. In most cases, the result will be zero, but there is one
// class of cases where it is not, so we cannot optimize without checking
// for it. The case is when you are shifting a signed value by 1 less than
// the number of bits in the value. For example:
// %X = shl sbyte %Y, ubyte 7
// will try to form an sbyte multiplier of 128, which will give a null
// multiplier, even though the result is not 0. Until we can check for this
// case, be conservative. TODO.
//
if (Multiplier == 0)
return Expr;
return ExprType(DefOne(Left.Scale, Ty) * Multiplier, Left.Var,
DefZero(Left.Offset, Ty) * Multiplier);
} // end case Instruction::Shl
case Instruction::Mul: {
ExprType Left (ClassifyExpr(I->getOperand(0)));
ExprType Right(ClassifyExpr(I->getOperand(1)));
if (Left.ExprTy > Right.ExprTy)
std::swap(Left, Right); // Make left be simpler than right
if (Left.ExprTy != ExprType::Constant) // RHS must be > constant
return I; // Quadratic eqn! :(
const ConstantInt *Offs = Left.Offset;
if (Offs == 0) return ExprType();
return ExprType( DefOne(Right.Scale , Ty) * Offs, Right.Var,
DefZero(Right.Offset, Ty) * Offs);
} // end case Instruction::Mul
case Instruction::Cast: {
ExprType Src(ClassifyExpr(I->getOperand(0)));
const Type *DestTy = I->getType();
if (isa<PointerType>(DestTy))
DestTy = Type::ULongTy; // Pointer types are represented as ulong
const Type *SrcValTy = Src.getExprType(0);
if (!SrcValTy) return I;
if (!SrcValTy->isLosslesslyConvertibleTo(DestTy)) {
if (Src.ExprTy != ExprType::Constant)
return I; // Converting cast, and not a constant value...
}
const ConstantInt *Offset = Src.Offset;
const ConstantInt *Scale = Src.Scale;
if (Offset) {
const Constant *CPV = ConstantExpr::getCast((Constant*)Offset, DestTy);
if (!isa<ConstantInt>(CPV)) return I;
Offset = cast<ConstantInt>(CPV);
}
if (Scale) {
const Constant *CPV = ConstantExpr::getCast((Constant*)Scale, DestTy);
if (!CPV) return I;
Scale = cast<ConstantInt>(CPV);
}
return ExprType(Scale, Src.Var, Offset);
} // end case Instruction::Cast
// TODO: Handle SUB, SHR?
} // end switch
// Otherwise, I don't know anything about this value!
return I;
}