diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index f1b6f2bb7de4f4942e6880d8f7c310e9e5a32b93..d7a551cb49f9c3fff64459a1e243ee988ef60bc0 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -148,7 +148,7 @@ cl::opt<bool> EnableConstraintElimination(
         "Enable pass to eliminate conditions based on linear constraints."));
 
 cl::opt<bool> EnableFunctionSpecialization(
-    "enable-function-specialization", cl::init(false), cl::Hidden,
+    "enable-function-specialization", cl::init(true), cl::Hidden,
     cl::desc("Enable Function Specialization pass"));
 
 cl::opt<AttributorRunOption> AttributorRun(