diff options
| -rw-r--r-- | lib/VMCore/ConstantFold.cpp | 48 |
1 files changed, 33 insertions, 15 deletions
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index b8001506f3..7eb7d4d8f8 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -828,10 +828,6 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V, const Type *DestTy) { const Type *SrcTy = V->getType(); - // Handle some simple cases - if (SrcTy == DestTy) - return (Constant*)V; // no-op cast - if (isa<UndefValue>(V)) return UndefValue::get(DestTy); @@ -901,6 +897,8 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V, return ConstantIntegral::get(DestTy, CI->getZExtValue()); return 0; case Instruction::BitCast: + if (SrcTy == DestTy) return (Constant*)V; // no-op cast + // Check to see if we are casting a pointer to an aggregate to a pointer to // the first element. If so, return the appropriate GEP instruction. if (const PointerType *PTy = dyn_cast<PointerType>(V->getType())) @@ -960,18 +958,38 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V, } } - // Handle sign conversion for integer no-op casts. We need to cast the - // value to the correct signedness before we try to cast it to the - // destination type. Be careful to do this only for integer types. - if (isa<ConstantIntegral>(V) && SrcTy->isInteger()) { - if (SrcTy->isSigned()) - V = ConstantInt::get(SrcTy->getUnsignedVersion(), - cast<ConstantIntegral>(V)->getZExtValue()); - else - V = ConstantInt::get(SrcTy->getSignedVersion(), - cast<ConstantIntegral>(V)->getSExtValue()); + // Finally, implement bitcast folding now. The code below doesn't handle + // bitcast right. + if (isa<ConstantPointerNull>(V)) // ptr->ptr cast. + return ConstantPointerNull::get(cast<PointerType>(DestTy)); + + // Handle integral constant input. + if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) { + // Integral -> Integral, must be changing sign. + if (DestTy->isIntegral()) + return ConstantInt::get(DestTy, CI->getZExtValue()); + + if (DestTy->isFloatingPoint()) { + if (DestTy == Type::FloatTy) + return ConstantFP::get(DestTy, BitsToFloat(CI->getZExtValue())); + assert(DestTy == Type::DoubleTy && "Unknown FP type!"); + return ConstantFP::get(DestTy, BitsToDouble(CI->getZExtValue())); + } + // Otherwise, can't fold this (packed?) + return 0; } - break; + + // Handle ConstantFP input. + if (const ConstantFP *FP = dyn_cast<ConstantFP>(V)) { + // FP -> Integral. + if (DestTy->isIntegral()) { + if (DestTy == Type::FloatTy) + return ConstantInt::get(DestTy, FloatToBits(FP->getValue())); + assert(DestTy == Type::DoubleTy && "Unknown FP type!"); + return ConstantInt::get(DestTy, DoubleToBits(FP->getValue())); + } + } + return 0; default: assert(!"Invalid CE CastInst opcode"); break; |