From e6794490ec188b39c4378c81d6a3116fa6fc5692 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 12 Aug 2002 21:17:25 +0000 Subject: [PATCH] * Factor a bunch of code by using ReplaceInstUsesWith * Move isMaxValue, isMinValue, isAllOnesValue to Constants.h llvm-svn: 3290 --- .../Scalar/InstructionCombining.cpp | 214 +++++------------- 1 file changed, 51 insertions(+), 163 deletions(-) diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index ba97be630349..20c7dbe8d3fc 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -1,4 +1,4 @@ -//===- InstructionCombining.cpp - Combine multiple instructions -------------=// +//===- InstructionCombining.cpp - Combine multiple instructions -----------===// // // InstructionCombining - Combine instructions to form fewer, simple // instructions. This pass does not modify the CFG, and has a tendancy to @@ -57,7 +57,7 @@ namespace { // instruction types. The semantics are as follows: // Return Value: // null - No change was made - // I - Change was made, I is still valid + // I - Change was made, I is still valid, I may be dead though // otherwise - Change was made, replace I with returned instruction // Instruction *visitNot(UnaryOperator &I); @@ -107,11 +107,8 @@ namespace { Instruction *InstCombiner::visitNot(UnaryOperator &I) { // not (not X) = X if (Instruction *Op = dyn_cast(I.getOperand(0))) - if (Op->getOpcode() == Instruction::Not) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op->getOperand(0)); - return &I; - } + if (Op->getOpcode() == Instruction::Not) + return ReplaceInstUsesWith(I, Op->getOperand(0)); return 0; } @@ -142,11 +139,8 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) { Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); // Eliminate 'add int %X, 0' - if (RHS == Constant::getNullValue(I.getType())) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(LHS); - return &I; - } + if (RHS == Constant::getNullValue(I.getType())) + return ReplaceInstUsesWith(I, LHS); // -A + B --> B - A if (Value *V = dyn_castNegInst(LHS)) @@ -182,11 +176,8 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) { Instruction *InstCombiner::visitSub(BinaryOperator &I) { Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - if (Op0 == Op1) { // sub X, X -> 0 - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Constant::getNullValue(I.getType())); - return &I; - } + if (Op0 == Op1) // sub X, X -> 0 + return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); // If this is a subtract instruction with a constant RHS, convert it to an add // instruction of a negative constant @@ -195,7 +186,7 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) { if (Constant *RHS = *Constant::getNullValue(I.getType()) - *Op2) // 0 - RHS return BinaryOperator::create(Instruction::Add, Op0, RHS, I.getName()); - // If this is a 'C = x-B', check to see if 'B = -A', so that C = x+A... + // If this is a 'B = x-(-A)', change to B = x+A... if (Value *V = dyn_castNegInst(Op1)) return BinaryOperator::create(Instruction::Add, Op0, V); @@ -219,25 +210,17 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) { bool Changed = SimplifyBinOp(I); Value *Op1 = I.getOperand(0); - // Simplify add instructions with a constant RHS... + // Simplify mul instructions with a constant RHS... if (Constant *Op2 = dyn_cast(I.getOperand(1))) { - if (I.getType()->isIntegral() && cast(Op2)->equalsInt(1)){ - // Eliminate 'mul int %X, 1' - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op1); - return &I; + if (I.getType()->isIntegral() && cast(Op2)->equalsInt(1)) + return ReplaceInstUsesWith(I, Op1); // Eliminate 'mul int %X, 1' - } else if (I.getType()->isIntegral() && - cast(Op2)->equalsInt(2)) { + if (I.getType()->isIntegral() && cast(Op2)->equalsInt(2)) // Convert 'mul int %X, 2' to 'add int %X, %X' return BinaryOperator::create(Instruction::Add, Op1, Op1, I.getName()); - } else if (Op2->isNullValue()) { - // Eliminate 'mul int %X, 0' - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op2); // Set this value to zero directly - return &I; - } + if (Op2->isNullValue()) + return ReplaceInstUsesWith(I, Op2); // Eliminate 'mul int %X, 0' } return Changed ? &I : 0; @@ -247,11 +230,8 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) { Instruction *InstCombiner::visitDiv(BinaryOperator &I) { // div X, 1 == X if (ConstantInt *RHS = dyn_cast(I.getOperand(1))) - if (RHS->equalsInt(1)) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(I.getOperand(0)); - return &I; - } + if (RHS->equalsInt(1)) + return ReplaceInstUsesWith(I, I.getOperand(0)); return 0; } @@ -259,70 +239,14 @@ Instruction *InstCombiner::visitDiv(BinaryOperator &I) { Instruction *InstCombiner::visitRem(BinaryOperator &I) { // rem X, 1 == 0 if (ConstantInt *RHS = dyn_cast(I.getOperand(1))) - if (RHS->equalsInt(1)) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Constant::getNullValue(I.getType())); - return &I; - } + if (RHS->equalsInt(1)) + return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); + return 0; } -// FIXME: These should be moved to Constants.h - -// isAllOnesValue - Return true if integral or boolean value is all ones. -static bool isAllOnesValue(const Constant *C) { - if (const ConstantBool *CB = dyn_cast(C)) - return CB == ConstantBool::True; - else if (const ConstantSInt *CS = dyn_cast(C)) - return CS->getValue() == -1; - else if (const ConstantUInt *CU = dyn_cast(C)) { - // Calculate -1 casted to the right type... - unsigned TypeBits = C->getType()->getPrimitiveSize()*8; - uint64_t Val = ~0ULL; // All ones - Val >>= 64-TypeBits; // Shift out unwanted 1 bits... - return CU->getValue() == Val; - } - - return false; -} - -// isMaxValue - Return true if this is the maximum value for this type. -static bool isMaxValue(const Constant *C) { - if (const ConstantBool *CB = dyn_cast(C)) - return CB == ConstantBool::True; - else if (const ConstantUInt *CU = dyn_cast(C)) - return isAllOnesValue(C); - else if (const ConstantSInt *CS = dyn_cast(C)) { - // Calculate 011111111111111... - unsigned TypeBits = C->getType()->getPrimitiveSize()*8; - int64_t Val = INT64_MAX; // All ones - Val >>= 64-TypeBits; // Shift out unwanted 1 bits... - return CS->getValue() == Val; - } - - return false; -} - -// isMinValue - Return true if this is the minimum value for this type. -static bool isMinValue(const Constant *C) { - if (const ConstantBool *CB = dyn_cast(C)) - return CB == ConstantBool::False; - else if (const ConstantUInt *CU = dyn_cast(C)) - return CU->getValue() == 0; - else if (const ConstantSInt *CS = dyn_cast(C)) { - // Calculate 1111111111000000000000 - unsigned TypeBits = C->getType()->getPrimitiveSize()*8; - int64_t Val = -1; // All ones - Val <<= TypeBits-1; // Shift over to the right spot - return CS->getValue() == Val; - } - return false; -} - // isMaxValueMinusOne - return true if this is Max-1 -static bool isMaxValueMinusOne(const Constant *C) { - if (!isa(C)) return false; - +static bool isMaxValueMinusOne(const ConstantInt *C) { if (const ConstantUInt *CU = dyn_cast(C)) { // Calculate -1 casted to the right type... unsigned TypeBits = C->getType()->getPrimitiveSize()*8; @@ -341,9 +265,7 @@ static bool isMaxValueMinusOne(const Constant *C) { } // isMinValuePlusOne - return true if this is Min+1 -static bool isMinValuePlusOne(const Constant *C) { - if (!isa(C)) return false; - +static bool isMinValuePlusOne(const ConstantInt *C) { if (const ConstantUInt *CU = dyn_cast(C)) return CU->getValue() == 1; @@ -357,25 +279,18 @@ static bool isMinValuePlusOne(const Constant *C) { } - Instruction *InstCombiner::visitAnd(BinaryOperator &I) { bool Changed = SimplifyBinOp(I); Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); // and X, X = X and X, 0 == 0 - if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType())) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op1); - return &I; - } + if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType())) + return ReplaceInstUsesWith(I, Op1); // and X, -1 == X - if (Constant *RHS = dyn_cast(Op1)) - if (isAllOnesValue(RHS)) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op0); - return &I; - } + if (ConstantGenericIntegral *RHS = dyn_cast(Op1)) + if (RHS->isAllOnesValue()) + return ReplaceInstUsesWith(I, Op0); return Changed ? &I : 0; } @@ -387,19 +302,13 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) { Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); // or X, X = X or X, 0 == X - if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType())) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op0); - return &I; - } + if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType())) + return ReplaceInstUsesWith(I, Op0); // or X, -1 == -1 - if (Constant *RHS = dyn_cast(Op1)) - if (isAllOnesValue(RHS)) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op1); - return &I; - } + if (ConstantGenericIntegral *RHS = dyn_cast(Op1)) + if (RHS->isAllOnesValue()) + return ReplaceInstUsesWith(I, Op1); return Changed ? &I : 0; } @@ -411,22 +320,16 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) { Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); // xor X, X = 0 - if (Op0 == Op1) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Constant::getNullValue(I.getType())); - return &I; - } + if (Op0 == Op1) + return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); - if (Constant *Op1C = dyn_cast(Op1)) { + if (ConstantGenericIntegral *Op1C = dyn_cast(Op1)) { // xor X, 0 == X - if (Op1C->isNullValue()) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op0); - return &I; - } + if (Op1C->isNullValue()) + return ReplaceInstUsesWith(I, Op0); // xor X, -1 = not X - if (isAllOnesValue(Op1C)) + if (Op1C->isAllOnesValue()) return UnaryOperator::create(Instruction::Not, Op0, I.getName()); } @@ -506,7 +409,7 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { // if (ConstantInt *CI = dyn_cast(Op1)) { // Check to see if we are comparing against the minimum or maximum value... - if (isMinValue(CI)) { + if (CI->isMinValue()) { if (I.getOpcode() == Instruction::SetLT) // A < MIN -> FALSE return ReplaceInstUsesWith(I, ConstantBool::False); if (I.getOpcode() == Instruction::SetGE) // A >= MIN -> TRUE @@ -516,7 +419,7 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { if (I.getOpcode() == Instruction::SetGT) // A > MIN -> A != MIN return BinaryOperator::create(Instruction::SetNE, Op0,Op1, I.getName()); - } else if (isMaxValue(CI)) { + } else if (CI->isMaxValue()) { if (I.getOpcode() == Instruction::SetGT) // A > MAX -> FALSE return ReplaceInstUsesWith(I, ConstantBool::False); if (I.getOpcode() == Instruction::SetLE) // A <= MAX -> TRUE @@ -557,23 +460,17 @@ Instruction *InstCombiner::visitShiftInst(Instruction &I) { // shl X, 0 == X and shr X, 0 == X // shl 0, X == 0 and shr 0, X == 0 if (Op1 == Constant::getNullValue(Type::UByteTy) || - Op0 == Constant::getNullValue(Op0->getType())) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Op0); - return &I; - } + Op0 == Constant::getNullValue(Op0->getType())) + return ReplaceInstUsesWith(I, Op0); - // shl int X, 32 = 0 and shr sbyte Y, 9 = 0, ... just don't eliminate shr of + // shl uint X, 32 = 0 and shr ubyte Y, 9 = 0, ... just don't eliminate shr of // a signed value. // if (ConstantUInt *CUI = dyn_cast(Op1)) { unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8; if (CUI->getValue() >= TypeBits && - !(Op0->getType()->isSigned() && I.getOpcode() == Instruction::Shr)) { - AddUsesToWorkList(I); // Add all modified instrs to worklist - I.replaceAllUsesWith(Constant::getNullValue(Op0->getType())); - return &I; - } + !(Op0->getType()->isSigned() && I.getOpcode() == Instruction::Shr)) + return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType())); } return 0; } @@ -626,11 +523,8 @@ static inline bool isEliminableCastOfCast(const CastInst &CI, Instruction *InstCombiner::visitCastInst(CastInst &CI) { // If the user is casting a value to the same type, eliminate this cast // instruction... - if (CI.getType() == CI.getOperand(0)->getType()) { - AddUsesToWorkList(CI); // Add all modified instrs to worklist - CI.replaceAllUsesWith(CI.getOperand(0)); - return &CI; - } + if (CI.getType() == CI.getOperand(0)->getType()) + return ReplaceInstUsesWith(CI, CI.getOperand(0)); // If casting the result of another cast instruction, try to eliminate this // one! @@ -667,11 +561,8 @@ Instruction *InstCombiner::visitCastInst(CastInst &CI) { // Instruction *InstCombiner::visitPHINode(PHINode &PN) { // If the PHI node only has one incoming value, eliminate the PHI node... - if (PN.getNumIncomingValues() == 1) { - AddUsesToWorkList(PN); // Add all modified instrs to worklist - PN.replaceAllUsesWith(PN.getIncomingValue(0)); - return &PN; - } + if (PN.getNumIncomingValues() == 1) + return ReplaceInstUsesWith(PN, PN.getIncomingValue(0)); return 0; } @@ -682,11 +573,8 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { // If so, eliminate the noop. if ((GEP.getNumOperands() == 2 && GEP.getOperand(1) == Constant::getNullValue(Type::UIntTy)) || - GEP.getNumOperands() == 1) { - AddUsesToWorkList(GEP); // Add all modified instrs to worklist - GEP.replaceAllUsesWith(GEP.getOperand(0)); - return &GEP; - } + GEP.getNumOperands() == 1) + return ReplaceInstUsesWith(GEP, GEP.getOperand(0)); // Combine Indices - If the source pointer to this getelementptr instruction // is a getelementptr instruction, combine the indices of the two