[DAG] Allow truncated and extend memory operations in Store Merge. NFCI.

As all store merges checks are based on the memory operation
performed, allow use of truncated stores and extended loads as valid
input candidates for merging.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305468 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index b5e1b492e96cfd2368dc9a9c9644503ffb75ff1e..3a9c17045c1b769418c1364baa2f0ddda695a384 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -12874,9 +12874,6 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode *St) {
       if (Ld->isVolatile() || Ld->isIndexed())
         break;
 
-      // We do not accept ext loads.
-      if (Ld->getExtensionType() != ISD::NON_EXTLOAD)
-        break;
 
       // The stored memory type must be the same.
       if (Ld->getMemoryVT() != MemVT)
@@ -13014,17 +13011,31 @@ bool DAGCombiner::MergeConsecutiveStores(StoreSDNode *St) {
 
     // The merged loads are required to have the same incoming chain, so
     // using the first's chain is acceptable.
-    SDValue NewLoad = DAG.getLoad(JointMemOpVT, LoadDL, FirstLoad->getChain(),
-                                  FirstLoad->getBasePtr(),
-                                  FirstLoad->getPointerInfo(), FirstLoadAlign);
 
     SDValue NewStoreChain = getMergeStoreChains(StoreNodes, NumElem);
-
     AddToWorklist(NewStoreChain.getNode());
 
-    SDValue NewStore = DAG.getStore(
-        NewStoreChain, StoreDL, NewLoad, FirstInChain->getBasePtr(),
-        FirstInChain->getPointerInfo(), FirstStoreAlign);
+    SDValue NewLoad, NewStore;
+    if (TLI.isTypeLegal(JointMemOpVT)) {
+      NewLoad = DAG.getLoad(JointMemOpVT, LoadDL, FirstLoad->getChain(),
+                            FirstLoad->getBasePtr(),
+                            FirstLoad->getPointerInfo(), FirstLoadAlign);
+      NewStore = DAG.getStore(NewStoreChain, StoreDL, NewLoad,
+                              FirstInChain->getBasePtr(),
+                              FirstInChain->getPointerInfo(), FirstStoreAlign);
+    } else { // This must be the truncstore/extload case
+      EVT ExtendedTy =
+          TLI.getTypeToTransformTo(*DAG.getContext(), JointMemOpVT);
+      NewLoad = DAG.getExtLoad(ISD::EXTLOAD, LoadDL, ExtendedTy,
+                               FirstLoad->getChain(), FirstLoad->getBasePtr(),
+                               FirstLoad->getPointerInfo(), JointMemOpVT,
+                               FirstLoadAlign);
+      NewStore = DAG.getTruncStore(NewStoreChain, StoreDL, NewLoad,
+                                   FirstInChain->getBasePtr(),
+                                   FirstInChain->getPointerInfo(), JointMemOpVT,
+                                   FirstInChain->getAlignment(),
+                                   FirstInChain->getMemOperand()->getFlags());
+    }
 
     // Transfer chain users from old loads to the new load.
     for (unsigned i = 0; i < NumElem; ++i) {