diff --git a/lld/COFF/Options.td b/lld/COFF/Options.td
--- a/lld/COFF/Options.td
+++ b/lld/COFF/Options.td
@@ -245,8 +245,8 @@
     "Context sensitive profile file path">;
 defm lto_cspgo_warn_mismatch: B<
      "lto-cspgo-warn-mismatch",
-     "turn on warnings about profile mismatch (default)>",
-     "turn off warnings about profile mismatch">;
+     "turn on warnings about profile cfg mismatch (default)>",
+     "turn off warnings about profile cfg mismatch">;
 def dash_dash_version : Flag<["--"], "version">,
   HelpText<"Display the version number and exit">;
 def threads
diff --git a/llvm/include/llvm/LTO/Config.h b/llvm/include/llvm/LTO/Config.h
--- a/llvm/include/llvm/LTO/Config.h
+++ b/llvm/include/llvm/LTO/Config.h
@@ -70,8 +70,9 @@
   /// Run PGO context sensitive IR instrumentation.
   bool RunCSIRInstr = false;
 
-  /// Turn on/off warnings about PGO context sensitive profile mismatch.
-  bool CSPGOWarnMismatch = false;
+  /// Turn on/off the warning about a hash mismatch in the context sensitive
+  /// PGO profile data.
+  bool CSPGOWarnMismatch = true;
 
   /// Asserts whether we can assume whole program visibility during the LTO
   /// link.