diff --git a/llvm/lib/Transforms/IPO/PartialInlining.cpp b/llvm/lib/Transforms/IPO/PartialInlining.cpp
--- a/llvm/lib/Transforms/IPO/PartialInlining.cpp
+++ b/llvm/lib/Transforms/IPO/PartialInlining.cpp
@@ -181,7 +181,7 @@
 
   // Container for outline regions
   struct OutlineRegionInfo {
-    OutlineRegionInfo(SmallVector<BasicBlock *, 8> Region,
+    OutlineRegionInfo(const SmallVector<BasicBlock *, 8> &Region,
                       BasicBlock *EntryBlock, BasicBlock *ExitBlock,
                       BasicBlock *ReturnBlock)
         : Region(Region), EntryBlock(EntryBlock), ExitBlock(ExitBlock),