X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FExpressions.cpp;h=bfab20c42c8f49feee9ee64c444956ba50664cef;hb=c53544af06acf3fba1788613a364f1f40317869e;hp=2194d1f1ee869f599c96b808ceaf48daf2d5e414;hpb=8e195e02fee65e2c9ca23111c37abd14890c7c9e;p=oota-llvm.git diff --git a/lib/Analysis/Expressions.cpp b/lib/Analysis/Expressions.cpp index 2194d1f1ee8..bfab20c42c8 100644 --- a/lib/Analysis/Expressions.cpp +++ b/lib/Analysis/Expressions.cpp @@ -8,48 +8,83 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/Expressions.h" -#include "llvm/Optimizations/ConstantHandling.h" -#include "llvm/Method.h" -#include "llvm/BasicBlock.h" +#include "llvm/ConstantHandling.h" +#include "llvm/Function.h" + +ExprType::ExprType(Value *Val) { + if (Val) + if (ConstantInt *CPI = dyn_cast(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; +} + -using namespace opt; // Get all the constant handling stuff -using namespace analysis; class DefVal { - const ConstPoolInt * const Val; + const ConstantInt * const Val; const Type * const Ty; protected: - inline DefVal(const ConstPoolInt *val, const Type *ty) : Val(val), Ty(ty) {} + inline DefVal(const ConstantInt *val, const Type *ty) : Val(val), Ty(ty) {} public: inline const Type *getType() const { return Ty; } - inline const ConstPoolInt *getVal() const { return Val; } - inline operator const ConstPoolInt * () const { return Val; } - inline const ConstPoolInt *operator->() const { return Val; } + 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 ConstPoolInt *val, const Type *ty) : DefVal(val, ty) {} - inline DefZero(const ConstPoolInt *val) : DefVal(val, val->getType()) {} + 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 ConstPoolInt *val, const Type *ty) : DefVal(val, ty) {} + inline DefOne(const ConstantInt *val, const Type *ty) : DefVal(val, ty) {} }; -// getIntegralConstant - Wrapper around the ConstPoolInt member of the same -// name. This method first checks to see if the desired constant is already in -// the constant pool. If it is, it is quickly recycled, otherwise a new one -// is allocated and added to the constant pool. +// 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 ConstPoolInt *getIntegralConstant(unsigned char V, const Type *Ty) { - return ConstPoolInt::get(Ty, V); -} - -static ConstPoolInt *getUnsignedConstant(uint64_t V, const Type *Ty) { - if (Ty->isPointerType()) Ty = Type::ULongTy; - - return Ty->isSigned() ? ConstPoolSInt::get(Ty, V) : ConstPoolUInt::get(Ty, V); +static ConstantInt *getUnsignedConstant(uint64_t V, const Type *Ty) { + if (isa(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 @@ -64,42 +99,39 @@ static ConstPoolInt *getUnsignedConstant(uint64_t V, const Type *Ty) { // 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 ConstPoolInt *Add(const ConstPoolInt *Arg1, - const ConstPoolInt *Arg2, bool DefOne) { +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! - ConstPoolVal *Result = *Arg1 + *Arg2; + Constant *Result = *Arg1 + *Arg2; assert(Result && Result->getType() == Arg1->getType() && "Couldn't perform addition!"); - ConstPoolInt *ResultI = (ConstPoolInt*)Result; + ConstantInt *ResultI = cast(Result); // Check to see if the result is one of the special cases that we want to // recognize... - if (ResultI->equalsInt(DefOne ? 1 : 0)) { - // Yes it is, simply delete the constant and return null. - delete ResultI; - return 0; - } + if (ResultI->equalsInt(DefOne ? 1 : 0)) + return 0; // Yes it is, simply return null. return ResultI; } -inline const ConstPoolInt *operator+(const DefZero &L, const DefZero &R) { +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); } -inline const ConstPoolInt *operator+(const DefOne &L, const DefOne &R) { +inline const ConstantInt *operator+(const DefOne &L, const DefOne &R) { if (L == 0) { if (R == 0) - return getIntegralConstant(2, L.getType()); + return getUnsignedConstant(2, L.getType()); else - return Add(getIntegralConstant(1, L.getType()), R, true); + return Add(getUnsignedConstant(1, L.getType()), R, true); } else if (R == 0) { - return Add(L, getIntegralConstant(1, L.getType()), true); + return Add(L, getUnsignedConstant(1, L.getType()), true); } return Add(L, R, true); } @@ -117,41 +149,77 @@ inline const ConstPoolInt *operator+(const DefOne &L, const DefOne &R) { // 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. // -inline const ConstPoolInt *Mul(const ConstPoolInt *Arg1, - const ConstPoolInt *Arg2, bool DefOne = false) { +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! - ConstPoolVal *Result = *Arg1 * *Arg2; + Constant *Result = *Arg1 * *Arg2; assert(Result && Result->getType() == Arg1->getType() && - "Couldn't perform mult!"); - ConstPoolInt *ResultI = (ConstPoolInt*)Result; + "Couldn't perform multiplication!"); + ConstantInt *ResultI = cast(Result); // Check to see if the result is one of the special cases that we want to // recognize... - if (ResultI->equalsInt(DefOne ? 1 : 0)) { - // Yes it is, simply delete the constant and return null. - delete ResultI; - return 0; - } + if (ResultI->equalsInt(DefOne ? 1 : 0)) + return 0; // Yes it is, simply return null. return ResultI; } -inline const ConstPoolInt *operator*(const DefZero &L, const DefZero &R) { +inline const ConstantInt *operator*(const DefZero &L, const DefZero &R) { if (L == 0 || R == 0) return 0; return Mul(L, R, false); } -inline const ConstPoolInt *operator*(const DefOne &L, const DefZero &R) { - if (R == 0) return getIntegralConstant(0, L.getType()); +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, false); + return Mul(L, R, true); } -inline const ConstPoolInt *operator*(const DefZero &L, const DefOne &R) { - return R*L; +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(*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); +} // ClassifyExpression: Analyze an expression to determine the complexity of the @@ -160,49 +228,47 @@ inline const ConstPoolInt *operator*(const DefZero &L, const DefOne &R) { // Note that this analysis cannot get into infinite loops because it treats PHI // nodes as being an unknown linear expression. // -ExprType analysis::ClassifyExpression(Value *Expr) { +ExprType ClassifyExpression(Value *Expr) { assert(Expr != 0 && "Can't classify a null expression!"); + if (Expr->getType() == Type::FloatTy || Expr->getType() == Type::DoubleTy) + return Expr; // FIXME: Can't handle FP expressions + switch (Expr->getValueType()) { case Value::InstructionVal: break; // Instruction... hmmm... investigate. case Value::TypeVal: case Value::BasicBlockVal: - case Value::MethodVal: case Value::ModuleVal: - assert(0 && "Unexpected expression type to classify!"); - case Value::MethodArgumentVal: // Method arg: nothing known, return var + case Value::FunctionVal: default: + //assert(0 && "Unexpected expression type to classify!"); + std::cerr << "Bizarre thing to expr classify: " << Expr << "\n"; + return Expr; + case Value::GlobalVariableVal: // Global Variable & Function argument: + case Value::ArgumentVal: // nothing known, return variable itself return Expr; case Value::ConstantVal: // Constant value, just return constant - ConstPoolVal *CPV = Expr->castConstantAsserting(); - if (CPV->getType()->isIntegral()) { // It's an integral constant! - ConstPoolInt *CPI = (ConstPoolInt*)Expr; - return ExprType(CPI->equalsInt(0) ? 0 : (ConstPoolInt*)Expr); - } + if (ConstantInt *CPI = dyn_cast(cast(Expr))) + // It's an integral constant! + return ExprType(CPI->isNullValue() ? 0 : CPI); return Expr; } - Instruction *I = Expr->castInstructionAsserting(); + Instruction *I = cast(Expr); const Type *Ty = I->getType(); switch (I->getOpcode()) { // Handle each instruction type seperately case Instruction::Add: { ExprType Left (ClassifyExpression(I->getOperand(0))); ExprType Right(ClassifyExpression(I->getOperand(1))); - if (Left.ExprTy > Right.ExprTy) - 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 ExprType(I); // if not, we don't know anything! - - return ExprType( DefOne(Left.Scale , Ty) + DefOne(Right.Scale , Ty), - Left.Var, - DefZero(Left.Offset, Ty) + DefZero(Right.Offset, Ty)); - } + return handleAddition(Left, Right, I); } // end case Instruction::Add + case Instruction::Sub: { + ExprType Left (ClassifyExpression(I->getOperand(0))); + ExprType Right(ClassifyExpression(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(ClassifyExpression(I->getOperand(1))); if (Right.ExprTy != ExprType::Constant) break; @@ -210,9 +276,22 @@ ExprType analysis::ClassifyExpression(Value *Expr) { 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 = ((ConstPoolUInt*)Right.Offset)->getValue(); - ConstPoolInt *Multiplier = getUnsignedConstant(1ULL << ShiftAmount, Ty); - + uint64_t ShiftAmount = ((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 @@ -221,12 +300,12 @@ ExprType analysis::ClassifyExpression(Value *Expr) { ExprType Left (ClassifyExpression(I->getOperand(0))); ExprType Right(ClassifyExpression(I->getOperand(1))); if (Left.ExprTy > Right.ExprTy) - swap(Left, Right); // Make left be simpler than right + std::swap(Left, Right); // Make left be simpler than right if (Left.ExprTy != ExprType::Constant) // RHS must be > constant return I; // Quadratic eqn! :( - const ConstPoolInt *Offs = Left.Offset; + const ConstantInt *Offs = Left.Offset; if (Offs == 0) return ExprType(); return ExprType( DefOne(Right.Scale , Ty) * Offs, Right.Var, DefZero(Right.Offset, Ty) * Offs); @@ -234,20 +313,30 @@ ExprType analysis::ClassifyExpression(Value *Expr) { case Instruction::Cast: { ExprType Src(ClassifyExpression(I->getOperand(0))); - if (Src.ExprTy != ExprType::Constant) - return I; - const ConstPoolInt *Offs = Src.Offset; - if (Offs == 0) return ExprType(); - - if (I->getType()->isPointerType()) - return Offs; // Pointer types do not lose precision - - assert(I->getType()->isIntegral() && "Can only handle integral types!"); - - const ConstPoolVal *CPV =ConstRules::get(*Offs)->castTo(Offs, I->getType()); - if (!CPV) return I; - assert(CPV->getType()->isIntegral() && "Must have an integral type!"); - return (ConstPoolInt*)CPV; + const Type *DestTy = I->getType(); + if (isa(DestTy)) + DestTy = Type::ULongTy; // Pointer types are represented as ulong + + /* + if (!Src.getExprType(0)->isLosslesslyConvertableTo(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 = ConstantFoldCastInstruction(Offset, DestTy); + if (!CPV) return I; + Offset = cast(CPV); + } + if (Scale) { + const Constant *CPV = ConstantFoldCastInstruction(Scale, DestTy); + if (!CPV) return I; + Scale = cast(CPV); + } + return ExprType(Scale, Src.Var, Offset); } // end case Instruction::Cast // TODO: Handle SUB, SHR?