Index: llvm/lib/Transforms/IPO/HotColdSplitting.cpp
===================================================================
--- llvm/lib/Transforms/IPO/HotColdSplitting.cpp
+++ llvm/lib/Transforms/IPO/HotColdSplitting.cpp
@@ -164,6 +164,7 @@
     Changed = true;
   }
 
+  F.setSectionPrefix(".unlikely");
   return Changed;
 }
 
Index: llvm/test/Transforms/HotColdSplit/coldentrycount.ll
===================================================================
--- llvm/test/Transforms/HotColdSplit/coldentrycount.ll
+++ llvm/test/Transforms/HotColdSplit/coldentrycount.ll
@@ -41,3 +41,5 @@
 !12 = !{i32 999000, i64 100, i32 1}
 !13 = !{i32 999999, i64 1, i32 2}
 !14 = !{!"function_entry_count", i64 100}
+!15 = !{!"function_entry_count", i64 0}
+!16 = !{!"function_section_prefix", !".unlikely"}