Fix merges of non-zero vector stores

Now actually stores the non-zero constant instead of 0.
I somehow forgot to include this part of r238108.

The test change was just an independent instruction order swap,
so just add another check line to satisfy CHECK-NEXT.

llvm-svn: 239539

1 files changed, 19 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index a71c6761c75..4ffb4099e7f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -387,6 +387,13 @@ namespace {
       unsigned SequenceNum;
     };
 
+    /// This is a helper function for MergeStoresOfConstantsOrVecElts. Returns a
+    /// constant build_vector of the stored constant values in Stores.
+    SDValue getMergedConstantVectorStore(SelectionDAG &DAG,
+                                         SDLoc SL,
+                                         ArrayRef<MemOpLink> Stores,
+                                         EVT Ty) const;
+
     /// This is a helper function for MergeConsecutiveStores. When the source
     /// elements of the consecutive stores are all constants or all extracted
     /// vector elements, try to merge them into one larger store.
@@ -10576,6 +10583,17 @@ struct BaseIndexOffset {
 };
 } // namespace
 
+SDValue DAGCombiner::getMergedConstantVectorStore(SelectionDAG &DAG,
+                                                  SDLoc SL,
+                                                  ArrayRef<MemOpLink> Stores,
+                                                  EVT Ty) const {
+  SmallVector<SDValue, 8> BuildVector;
+
+  for (const MemOpLink &Store : Stores)
+    BuildVector.push_back(cast<StoreSDNode>(Store.MemNode)->getValue());
+  return DAG.getNode(ISD::BUILD_VECTOR, SL, Ty, BuildVector);
+}
+
 bool DAGCombiner::MergeStoresOfConstantsOrVecElts(
                   SmallVectorImpl<MemOpLink> &StoreNodes, EVT MemVT,
                   unsigned NumElem, bool IsConstantSrc, bool UseVector) {
@@ -10606,12 +10624,7 @@ bool DAGCombiner::MergeStoresOfConstantsOrVecElts(
     EVT Ty = EVT::getVectorVT(*DAG.getContext(), MemVT, NumElem);
     assert(TLI.isTypeLegal(Ty) && "Illegal vector store");
     if (IsConstantSrc) {
-      // A vector store with a constant source implies that the constant is
-      // zero; we only handle merging stores of constant zeros because the zero
-      // can be materialized without a load.
-      // It may be beneficial to loosen this restriction to allow non-zero
-      // store merging.
-      StoredVal = DAG.getConstant(0, DL, Ty);
+      StoredVal = getMergedConstantVectorStore(DAG, DL, StoreNodes, Ty);
     } else {
       SmallVector<SDValue, 8> Ops;
       for (unsigned i = 0; i < NumElem ; ++i) {