Clarify a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52212 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Matthijs Kooijman 2008-06-11 09:00:12 +00:00
parent f7ea3638e0
commit b4d6a5a76c

View File

@ -10613,7 +10613,6 @@ static Value *FindScalarElement(Value *V, unsigned EltNo) {
}
Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
// If vector val is undef, replace extract with scalar undef.
if (isa<UndefValue>(EI.getOperand(0)))
return ReplaceInstUsesWith(EI, UndefValue::get(EI.getType()));
@ -10623,8 +10622,9 @@ Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
return ReplaceInstUsesWith(EI, Constant::getNullValue(EI.getType()));
if (ConstantVector *C = dyn_cast<ConstantVector>(EI.getOperand(0))) {
// If vector val is constant with uniform operands, replace EI
// with that operand
// 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) {