diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -36,6 +36,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/Analysis/CallGraphSCCPass.h"
 #include "llvm/Analysis/InlineAdvisor.h"
@@ -1804,6 +1805,10 @@
     if (!CallsitePrioritizedInline.getNumOccurrences())
       CallsitePrioritizedInline = true;
 
+    // Enable iterative-BFI by default for CSSPGO.
+    if (!UseIterativeBFIInference.getNumOccurrences())
+      UseIterativeBFIInference = true;
+
     // Tracker for profiles under different context
     ContextTracker =
         std::make_unique<SampleContextTracker>(Reader->getProfiles());