Index: include/llvm/ProfileData/InstrProf.h
===================================================================
--- include/llvm/ProfileData/InstrProf.h
+++ include/llvm/ProfileData/InstrProf.h
@@ -859,7 +859,9 @@
   // In this version, profile summary data \c IndexedInstrProf::Summary is
   // stored after the profile header.
   Version4 = 4,
-  // The current version is 4.
+  // In this version, the frontend PGO stable hash algorithm defaults to V2.
+  Version5 = 5,
+  // The current version is 5.
   CurrentVersion = INSTR_PROF_INDEX_VERSION
 };
 const uint64_t Version = ProfVersion::CurrentVersion;
Index: include/llvm/ProfileData/InstrProfData.inc
===================================================================
--- include/llvm/ProfileData/InstrProfData.inc
+++ include/llvm/ProfileData/InstrProfData.inc
@@ -628,7 +628,7 @@
 /* Raw profile format version (start from 1). */
 #define INSTR_PROF_RAW_VERSION 4
 /* Indexed profile format version (start from 1). */
-#define INSTR_PROF_INDEX_VERSION 4
+#define INSTR_PROF_INDEX_VERSION 5
 /* Coverage mapping format vresion (start from 0). */
 #define INSTR_PROF_COVMAP_VERSION 2