diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index d67a665..a035cd8 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -789,7 +789,8 @@
   CI->getPreprocessorOpts().RetainRemappedFileBuffers = true;
   
   llvm::MemoryBuffer *OverrideMainBuffer = 0;
-  if (PrecompilePreamble)
+  // FIXME: When C++ PCH is ready, allow use of it for a precompiled preamble.
+  if (PrecompilePreamble && !CI->getLangOpts().CPlusPlus)
     OverrideMainBuffer = AST->BuildPrecompiledPreamble();
   
   if (!AST->Parse(OverrideMainBuffer))