X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FConstantFolding.cpp;h=68a55b6b94d50b80b682522c29f8ec6c9b3b5ce2;hb=48f17ba2a611d197082d4de730b646a4ecf68df4;hp=f2e89a773e7dc945f180a9e4aa90ad22f5214ea4;hpb=c0362d5c6e0066c741bce056a65d8b4c026de19f;p=oota-llvm.git diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp index f2e89a773e7..68a55b6b94d 100644 --- a/lib/Analysis/ConstantFolding.cpp +++ b/lib/Analysis/ConstantFolding.cpp @@ -30,7 +30,7 @@ #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/GetElementPtrTypeIterator.h" #include "llvm/Support/MathExtras.h" -#include "llvm/System/FEnv.h" +#include "llvm/Support/FEnv.h" #include #include using namespace llvm; @@ -538,7 +538,7 @@ static Constant *CastGEPIndices(Constant *const *Ops, unsigned NumOps, for (unsigned i = 1; i != NumOps; ++i) { if ((i == 1 || !isa(GetElementPtrInst::getIndexedType(Ops[0]->getType(), - reinterpret_cast(Ops+1), + reinterpret_cast(Ops+1), i-1))) && Ops[i]->getType() != IntPtrTy) { Any = true; @@ -610,10 +610,8 @@ static Constant *SymbolicallyEvaluateGEP(Constant *const *Ops, unsigned NumOps, APInt BasePtr(BitWidth, 0); if (ConstantExpr *CE = dyn_cast(Ptr)) if (CE->getOpcode() == Instruction::IntToPtr) - if (ConstantInt *Base = dyn_cast(CE->getOperand(0))) { - BasePtr = Base->getValue(); - BasePtr.zextOrTrunc(BitWidth); - } + if (ConstantInt *Base = dyn_cast(CE->getOperand(0))) + BasePtr = Base->getValue().zextOrTrunc(BitWidth); if (Ptr->isNullValue() || BasePtr != 0) { Constant *C = ConstantInt::get(Ptr->getContext(), Offset+BasePtr); return ConstantExpr::getIntToPtr(C, ResultTy); @@ -639,12 +637,19 @@ static Constant *SymbolicallyEvaluateGEP(Constant *const *Ops, unsigned NumOps, // Determine which element of the array the offset points into. APInt ElemSize(BitWidth, TD->getTypeAllocSize(ATy->getElementType())); + const IntegerType *IntPtrTy = TD->getIntPtrType(Ty->getContext()); if (ElemSize == 0) - return 0; - APInt NewIdx = Offset.udiv(ElemSize); - Offset -= NewIdx * ElemSize; - NewIdxs.push_back(ConstantInt::get(TD->getIntPtrType(Ty->getContext()), - NewIdx)); + // The element size is 0. This may be [0 x Ty]*, so just use a zero + // index for this level and proceed to the next level to see if it can + // accommodate the offset. + NewIdxs.push_back(ConstantInt::get(IntPtrTy, 0)); + else { + // The element size is non-zero divide the offset by the element + // size (rounding down), to compute the index at this level. + APInt NewIdx = Offset.udiv(ElemSize); + Offset -= NewIdx * ElemSize; + NewIdxs.push_back(ConstantInt::get(IntPtrTy, NewIdx)); + } Ty = ATy->getElementType(); } else if (const StructType *STy = dyn_cast(Ty)) { // Determine which field of the struct the offset points into. The @@ -688,22 +693,23 @@ static Constant *SymbolicallyEvaluateGEP(Constant *const *Ops, unsigned NumOps, // Constant Folding public APIs //===----------------------------------------------------------------------===// - -/// ConstantFoldInstruction - Attempt to constant fold the specified -/// instruction. If successful, the constant result is returned, if not, null -/// is returned. Note that this function can only fail when attempting to fold -/// instructions like loads and stores, which have no constant expression form. -/// +/// ConstantFoldInstruction - Try to constant fold the specified instruction. +/// If successful, the constant result is returned, if not, null is returned. +/// Note that this fails if not all of the operands are constant. Otherwise, +/// this function can only fail when attempting to fold instructions like loads +/// and stores, which have no constant expression form. Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) { - // Handle PHI nodes specially here... + // Handle PHI nodes quickly here... if (PHINode *PN = dyn_cast(I)) { Constant *CommonValue = 0; for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { Value *Incoming = PN->getIncomingValue(i); - // If the incoming value is equal to the phi node itself or is undef then - // skip it. - if (Incoming == PN || isa(Incoming)) + // If the incoming value is undef then skip it. Note that while we could + // skip the value if it is equal to the phi node itself we choose not to + // because that would break the rule that constant folding only applies if + // all operands are constants. + if (isa(Incoming)) continue; // If the incoming value is not a constant, or is a different constant to // the one we saw previously, then give up. @@ -732,7 +738,18 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) { if (const LoadInst *LI = dyn_cast(I)) return ConstantFoldLoadInst(LI, TD); - + + if (InsertValueInst *IVI = dyn_cast(I)) + return ConstantExpr::getInsertValue( + cast(IVI->getAggregateOperand()), + cast(IVI->getInsertedValueOperand()), + IVI->idx_begin(), IVI->getNumIndices()); + + if (ExtractValueInst *EVI = dyn_cast(I)) + return ConstantExpr::getExtractValue( + cast(EVI->getAggregateOperand()), + EVI->idx_begin(), EVI->getNumIndices()); + return ConstantFoldInstOperands(I->getOpcode(), I->getType(), Ops.data(), Ops.size(), TD); } @@ -743,7 +760,8 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const TargetData *TD) { Constant *llvm::ConstantFoldConstantExpression(const ConstantExpr *CE, const TargetData *TD) { SmallVector Ops; - for (User::const_op_iterator i = CE->op_begin(), e = CE->op_end(); i != e; ++i) { + for (User::const_op_iterator i = CE->op_begin(), e = CE->op_end(); + i != e; ++i) { Constant *NewC = cast(*i); // Recursively fold the ConstantExpr's operands. if (ConstantExpr *NewCE = dyn_cast(NewC))