- // If vector val is undef, replace extract with scalar undef.
- if (isa<UndefValue>(EI.getOperand(0)))
- return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
-
- // If vector val is constant 0, replace extract with scalar 0.
- if (isa<ConstantAggregateZero>(EI.getOperand(0)))
- return ReplaceInstUsesWith(EI, Constant::getNullValue(EI.getType()));
-
- if (ConstantVector *C = dyn_cast<ConstantVector>(EI.getOperand(0))) {
- // If vector val is constant with all elements the same, replace EI with
- // that element. When the elements are not identical, we cannot replace yet
- // (we do that below, but only when the index is constant).
- Constant *op0 = C->getOperand(0);
- for (unsigned i = 1; i != C->getNumOperands(); ++i)
- if (C->getOperand(i) != op0) {
- op0 = 0;
- break;
- }
- if (op0)
- return ReplaceInstUsesWith(EI, op0);
- }
+ // If vector val is constant with all elements the same, replace EI with
+ // that element. We handle a known element # below.
+ if (Constant *C = dyn_cast<Constant>(EI.getOperand(0)))
+ if (CheapToScalarize(C, false))
+ return ReplaceInstUsesWith(EI, C->getAggregateElement(0U));