diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 58f931234e1..8236ca404df 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4715,7 +4715,7 @@ bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) {
     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;
diff --git a/test/CodeGen/ARM/2009-09-10-postdec.ll b/test/CodeGen/ARM/2009-09-10-postdec.ll
new file mode 100644
index 00000000000..10653b51c14
--- /dev/null
+++ b/test/CodeGen/ARM/2009-09-10-postdec.ll
@@ -0,0 +1,11 @@
+; RUN: llc -march=arm < %s | FileCheck %s
+; Radar 7213850
+
+define i32 @test(i8* %d, i32 %x, i32 %y) nounwind {
+  %1 = ptrtoint i8* %d to i32
+;CHECK: sub
+  %2 = sub i32 %x, %1
+  %3 = add nsw i32 %2, %y
+  store i8 0, i8* %d, align 1
+  ret i32 %3
+}