[SDAG] At the suggestion of Hal, switch to an output parameter that
tracks which elements of the build vector are in fact undef.
This should make actually inpsecting them (likely in my next patch)
reasonably pretty. Also makes the output parameter optional as it is
clear now that *most* users are happy with undefs in their splats.
llvm-svn: 212581
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index d58824a..7497feb 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -655,13 +655,13 @@
return CN;
if (BuildVectorSDNode *BV = dyn_cast<BuildVectorSDNode>(N)) {
- bool HasUndefElements;
- ConstantSDNode *CN = BV->getConstantSplatNode(HasUndefElements);
+ BitVector UndefElements;
+ ConstantSDNode *CN = BV->getConstantSplatNode(&UndefElements);
// BuildVectors can truncate their operands. Ignore that case here.
// FIXME: We blindly ignore splats which include undef which is overly
// pessimistic.
- if (CN && !HasUndefElements &&
+ if (CN && UndefElements.none() &&
CN->getValueType(0) == N.getValueType().getScalarType())
return CN;
}