[llvm] r305468 - [DAG] Allow truncated and extend memory operations in Store Merge. NFCI.

[Nirav Dave via llvm-commits]

Author: niravd
Date: Thu Jun 15 09:04:07 2017
New Revision: 305468

URL: http://llvm.org/viewvc/llvm-project?rev=305468&view=rev
Log:
[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.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=305468&r1=305467&r2=305468&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Thu Jun 15 09:04:07 2017
@@ -12874,9 +12874,6 @@ bool DAGCombiner::MergeConsecutiveStores
       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
 
     // 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) {