diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index c4082db009073..87190093767b0 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -615,7 +615,7 @@ static unsigned getOptimizationLevelSize(ArgList &Args) {
 static void GenerateArg(ArgumentConsumer Consumer,
                         llvm::opt::OptSpecifier OptSpecifier) {
   Option Opt = getDriverOptTable().getOption(OptSpecifier);
-  denormalizeSimpleFlag(Consumer, Opt.getPrefix() + Opt.getName(),
+  denormalizeSimpleFlag(Consumer, Opt.getPrefixedName(),
                         Option::OptionClass::FlagClass, 0);
 }
 
@@ -623,8 +623,7 @@ static void GenerateArg(ArgumentConsumer Consumer,
                         llvm::opt::OptSpecifier OptSpecifier,
                         const Twine &Value) {
   Option Opt = getDriverOptTable().getOption(OptSpecifier);
-  denormalizeString(Consumer, Opt.getPrefix() + Opt.getName(), Opt.getKind(), 0,
-                    Value);
+  denormalizeString(Consumer, Opt.getPrefixedName(), Opt.getKind(), 0, Value);
 }
 
 // Parse command line arguments into CompilerInvocation.