diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index 191b615..6f78ee1 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -160,8 +160,12 @@
   ContentCache *&Entry = FileInfos[FileEnt];
   if (Entry) return Entry;
   
-  // Nope, create a new Cache entry.
-  Entry = ContentCacheAlloc.Allocate<ContentCache>();
+  // Nope, create a new Cache entry.  Make sure it is at least 8-byte aligned
+  // so that FileInfo can use the low 3 bits of the pointer for its own
+  // nefarious purposes.
+  unsigned EntryAlign = llvm::AlignOf<ContentCache>::Alignment;
+  EntryAlign = std::max(8U, EntryAlign);
+  Entry = ContentCacheAlloc.Allocate<ContentCache>(1, EntryAlign);
   new (Entry) ContentCache(FileEnt);
   return Entry;
 }
@@ -171,11 +175,12 @@
 ///  memory buffer.  This does no caching.
 const ContentCache*
 SourceManager::createMemBufferContentCache(const MemoryBuffer *Buffer) {
-  // Add a new ContentCache to the MemBufferInfos list and return it.  We
-  // must default construct the object first that the instance actually
-  // stored within MemBufferInfos actually owns the Buffer, and not any
-  // temporary we would use in the call to "push_back".
-  ContentCache *Entry = ContentCacheAlloc.Allocate<ContentCache>();
+  // Add a new ContentCache to the MemBufferInfos list and return it.  Make sure
+  // it is at least 8-byte aligned so that FileInfo can use the low 3 bits of
+  // the pointer for its own nefarious purposes.
+  unsigned EntryAlign = llvm::AlignOf<ContentCache>::Alignment;
+  EntryAlign = std::max(8U, EntryAlign);
+  ContentCache *Entry = ContentCacheAlloc.Allocate<ContentCache>(1, EntryAlign);
   new (Entry) ContentCache();
   MemBufferInfos.push_back(Entry);
   Entry->setBuffer(Buffer);