Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -786,9 +786,9 @@
         return SDValue();
       }
       if (N1.hasOneUse()) {
-        // reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one
+        // reassoc. (op x, (op y, c1)) -> (op (op x, y), c1) iff x+c1 has one
         // use
-        SDValue OpNode = DAG.getNode(Opc, SDLoc(N0), VT, N1.getOperand(0), N0);
+        SDValue OpNode = DAG.getNode(Opc, SDLoc(N0), VT, N0, N1.getOperand(0));
         if (!OpNode.getNode())
           return SDValue();
         AddToWorklist(OpNode.getNode());
Index: test/CodeGen/R600/dagcombine-reassociate-bug.ll
===================================================================
--- /dev/null
+++ test/CodeGen/R600/dagcombine-reassociate-bug.ll
@@ -0,0 +1,33 @@
+; RUN: llc -march=amdgcn -mcpu=SI -verify-machineinstrs < %s | FileCheck %s
+
+; Test for a bug where DAGCombiner::ReassociateOps() was creating adds
+; with offset in the first operand and base pointers in the second.
+
+; CHECK-LABEL: {{^}}store_same_base_ptr:
+; CHECK: buffer_store_dword v{{[0-9]+}}, [[VADDR:v\[[0-9]+:[0-9]+\]]], [[SADDR:s\[[0-9]+:[0-9]+\]]]
+; CHECK: buffer_store_dword v{{[0-9]+}}, [[VADDR]], [[SADDR]]
+; CHECK: buffer_store_dword v{{[0-9]+}}, [[VADDR]], [[SADDR]]
+; CHECK: buffer_store_dword v{{[0-9]+}}, [[VADDR]], [[SADDR]]
+
+define void @store_same_base_ptr(i32 addrspace(1)* %out) {
+entry:
+  %id = call i32 @llvm.r600.read.tidig.x() #0
+  %offset = sext i32 %id to i64
+  %offset0 = add i64 %offset, 1027
+  %ptr0 = getelementptr i32 addrspace(1)* %out, i64 %offset0
+  store i32 3, i32 addrspace(1)* %ptr0
+  %offset1 = add i64 %offset, 1026
+  %ptr1 = getelementptr i32 addrspace(1)* %out, i64 %offset1
+  store i32 2, i32 addrspace(1)* %ptr1
+  %offset2 = add i64 %offset, 1025
+  %ptr2 = getelementptr i32 addrspace(1)* %out, i64 %offset2
+  store i32 1, i32 addrspace(1)* %ptr2
+  %offset3 = add i64 %offset, 1024
+  %ptr3 = getelementptr i32 addrspace(1)* %out, i64 %offset3
+  store i32 0, i32 addrspace(1)* %ptr3
+  ret void
+}
+
+declare i32 @llvm.r600.read.tidig.x() #0
+
+attributes #0 = { readnone }