diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index cecae0e..7f5909b 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -1471,7 +1471,7 @@
     return;
   }
 
-  if (NumParams.getLimitedValue(4) > S.Context.Target.getRegParmMax()) {
+  if (NumParams.getLimitedValue(255) > S.Context.Target.getRegParmMax()) {
     S.Diag(Attr.getLoc(), diag::err_attribute_regparm_invalid_number)
       << S.Context.Target.getRegParmMax() << NumParamsExpr->getSourceRange();
     return;