diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1851,12 +1851,7 @@
           << A->getSpelling() << T.str();
 
     const Option &O = A->getOption();
-    if (O.matches(OPT_mabi_EQ_vec_extabi))
-      Opts.EnableAIXExtendedAltivecABI = 1;
-    else if (O.matches(OPT_mabi_EQ_vec_default))
-      Opts.EnableAIXExtendedAltivecABI = 0;
-    else
-      Opts.EnableAIXExtendedAltivecABI = 0;
+    Opts.EnableAIXExtendedAltivecABI = O.matches(OPT_mabi_EQ_vec_extabi);
   }
 
   bool NeedLocTracking = false;