return 0;
}
-/// IsOneHotValue - Returns true for "one-hot" values (values where at most
-/// one bit can be set).
-static bool IsOneHotValue(Value *V) {
- // Match 1<<K.
- if (BinaryOperator *BO = dyn_cast<BinaryOperator>(V))
- if (BO->getOpcode() == Instruction::Shl) {
- ConstantInt *One = dyn_cast<ConstantInt>(BO->getOperand(0));
- return One && One->isOne();
- }
-
- // Check for power of two integer constants.
- if (ConstantInt *K = dyn_cast<ConstantInt>(V))
- return K->getValue().isPowerOf2();
-
- return false;
-}
-
/// FoldOrOfICmps - Fold (icmp)|(icmp) if possible.
Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
Value *Mask = 0;
Value *Masked = 0;
if (LAnd->getOperand(0) == RAnd->getOperand(0) &&
- IsOneHotValue(LAnd->getOperand(1)) &&
- IsOneHotValue(RAnd->getOperand(1))) {
+ isKnownToBeAPowerOfTwo(LAnd->getOperand(1)) &&
+ isKnownToBeAPowerOfTwo(RAnd->getOperand(1))) {
Mask = Builder->CreateOr(LAnd->getOperand(1), RAnd->getOperand(1));
Masked = Builder->CreateAnd(LAnd->getOperand(0), Mask);
} else if (LAnd->getOperand(1) == RAnd->getOperand(1) &&
- IsOneHotValue(LAnd->getOperand(0)) &&
- IsOneHotValue(RAnd->getOperand(0))) {
+ isKnownToBeAPowerOfTwo(LAnd->getOperand(0)) &&
+ isKnownToBeAPowerOfTwo(RAnd->getOperand(0))) {
Mask = Builder->CreateOr(LAnd->getOperand(0), RAnd->getOperand(0));
Masked = Builder->CreateAnd(LAnd->getOperand(1), Mask);
}