diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h
index 9fc7587..4336982 100644
--- a/include/clang/Basic/SourceManager.h
+++ b/include/clang/Basic/SourceManager.h
@@ -659,6 +659,10 @@
                               unsigned NumSLocEntries,
                               unsigned NextOffset);
 
+  /// \brief Clear out any preallocated source location entries that
+  /// haven't already been loaded.
+  void ClearPreallocatedSLocEntries();
+
 private:
   /// isOffsetInFileID - Return true if the specified FileID contains the
   /// specified SourceLocation offset.  This is a very hot method.
diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index 5057663..9ca00f5 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -318,6 +318,22 @@
   SLocEntryTable.resize(SLocEntryTable.size() + NumSLocEntries);
 }
 
+void SourceManager::ClearPreallocatedSLocEntries() {
+  unsigned I = 0;
+  for (unsigned N = SLocEntryLoaded.size(); I != N; ++I)
+    if (!SLocEntryLoaded[I])
+      break;
+
+  // We've already loaded all preallocated source location entries.
+  if (I == SLocEntryLoaded.size())
+    return;
+
+  // Remove everything from location I onward.
+  SLocEntryTable.resize(I);
+  SLocEntryLoaded.clear();
+  ExternalSLocEntries = 0;
+}
+
 
 //===----------------------------------------------------------------------===//
 // Methods to create new FileID's and instantiations.
diff --git a/lib/Frontend/PCHReader.cpp b/lib/Frontend/PCHReader.cpp
index d044fee..d36d836 100644
--- a/lib/Frontend/PCHReader.cpp
+++ b/lib/Frontend/PCHReader.cpp
@@ -1116,6 +1116,14 @@
         // FIXME: We could consider reading through to the end of this
         // PCH block, skipping subblocks, to see if there are other
         // PCH blocks elsewhere.
+
+        // Clear out any preallocated source location entries, so that
+        // the source manager does not try to resolve them later.
+        PP.getSourceManager().ClearPreallocatedSLocEntries();
+
+        // Remove the stat cache.
+        PP.getFileManager().setStatCache(0);
+
         return IgnorePCH;
       }
       break;