Add a comment which should hopefully make the purpose of this method a

bit clearer.

llvm-svn: 72374
This commit is contained in:
Eli Friedman 2009-05-24 20:32:10 +00:00
parent fd8b335ca4
commit ac149ee60a
1 changed files with 3 additions and 0 deletions
llvm/lib/CodeGen/SelectionDAG

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@ -224,6 +224,9 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
}
SDValue VectorLegalizer::PromoteVectorOp(SDValue Op) {
// Vector "promotion" is basically just bitcasting and doing the operation
// in a different type. For example, x86 promotes ISD::AND on v2i32 to
// v1i64.
MVT VT = Op.getValueType();
assert(Op.getNode()->getNumValues() == 1 &&
"Can't promote a vector with multiple results!");