diff options
Diffstat (limited to 'llvm/lib/VMCore/Constants.cpp')
| -rw-r--r-- | llvm/lib/VMCore/Constants.cpp | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/llvm/lib/VMCore/Constants.cpp b/llvm/lib/VMCore/Constants.cpp index 6dbc1449f24..17bad97e6f8 100644 --- a/llvm/lib/VMCore/Constants.cpp +++ b/llvm/lib/VMCore/Constants.cpp @@ -2007,6 +2007,26 @@ Constant *ConstantExpr::getAShr(Constant *C1, Constant *C2, bool isExact) { isExact ? PossiblyExactOperator::IsExact : 0); } +/// getBinOpIdentity - Return the identity for the given binary operation, +/// i.e. a constant C such that X op C = X and C op X = X for every X. It +/// is an error to call this for an operation that doesn't have an identity. +Constant *ConstantExpr::getBinOpIdentity(unsigned Opcode, Type *Ty) { + switch (Opcode) { + default: + llvm_unreachable("Not a binary operation with identity"); + case Instruction::Add: + case Instruction::Or: + case Instruction::Xor: + return Constant::getNullValue(Ty); + + case Instruction::Mul: + return ConstantInt::get(Ty, 1); + + case Instruction::And: + return Constant::getAllOnesValue(Ty); + } +} + // destroyConstant - Remove the constant from the constant table... // void ConstantExpr::destroyConstant() { |
