When optimizing certain BUILD_VECTOR nodes into other BUILD_VECTOR nodes, add the new node into the work list because there is a potential for further optimizations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152784 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 8337d76..32b9fa4 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -7422,6 +7422,8 @@
// will be type-legalized to complex code sequences.
// We perform this optimization only before the operation legalizer because we
// may introduce illegal operations.
+ // Create a new simpler BUILD_VECTOR sequence which other optimizations can
+ // turn into a single shuffle instruction.
if ((Level == AfterLegalizeVectorOps || Level == AfterLegalizeTypes) &&
ValidTypes) {
bool isLE = TLI.isLittleEndian();
@@ -7462,6 +7464,8 @@
SDValue BV = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
VecVT, &Ops[0], Ops.size());
+ // The new BUILD_VECTOR node has the potential to be further optimized.
+ AddToWorkList(BV.getNode());
// Bitcast to the desired type.
return DAG.getNode(ISD::BITCAST, dl, N->getValueType(0), BV);
}