Index: clang/lib/Serialization/ASTReader.cpp
===================================================================
--- clang/lib/Serialization/ASTReader.cpp
+++ clang/lib/Serialization/ASTReader.cpp
@@ -3632,7 +3632,8 @@
 
     // Check the primary module map file.
     const FileEntry *StoredModMap = FileMgr.getFile(F.ModuleMapPath);
-    if (StoredModMap == nullptr || StoredModMap != ModMap) {
+    if (!PP.getPreprocessorOpts().DisablePCHValidation &&
+        (StoredModMap == nullptr || StoredModMap != ModMap)) {
       assert(ModMap && "found module is missing module map file");
       assert(ImportedBy && "top-level import should be verified");
       if ((ClientLoadCapabilities & ARR_OutOfDate) == 0)