[DAG] Allow base element type of store merge type to also be a vector.

Correctly calculate merged vector size if MemVT is already a vector.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308312 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index b733ce7..d526dfd 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -12763,7 +12763,12 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode *St) {
              TLI.storeOfVectorConstantIsCheap(MemVT, i + 1, FirstStoreAS)) &&
             !NoVectors) {
           // Find a legal type for the vector store.
-          EVT Ty = EVT::getVectorVT(Context, MemVT, i + 1);
+          unsigned Elts = i + 1;
+          if (MemVT.isVector()) {
+            // When merging vector stores, get the total number of elements.
+            Elts *= MemVT.getVectorNumElements();
+          }
+          EVT Ty = EVT::getVectorVT(Context, MemVT.getScalarType(), Elts);
           if (TLI.isTypeLegal(Ty) &&
               TLI.canMergeStoresTo(FirstStoreAS, Ty, DAG) &&
               TLI.allowsMemoryAccess(Context, DL, Ty, FirstStoreAS,