Don't swap the operands of a subtraction when trying to create a
post-decrement load/store.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81464 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 58f9312..8236ca4 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4715,7 +4715,7 @@
     SDValue Offset;
     ISD::MemIndexedMode AM = ISD::UNINDEXED;
     if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) {
-      if (Ptr == Offset)
+      if (Ptr == Offset && Op->getOpcode() == ISD::ADD)
         std::swap(BasePtr, Offset);
       if (Ptr != BasePtr)
         continue;