-fprof-auto-top adds SCCs to INLINE instance methods

Summary

According to the User's Guide, the GHC flag -fprof-auto-top automatically adds SCC annotations "for all top-level bindings not marked INLINE", but it actually adds SCCs to INLINE instance methods.

Steps to reproduce

Here is a small example that reproduces the behavior: fprof-auto-top.hs

module Main where

data D = D

class C a where
  shouldn'tSCC :: a -> ()

instance C D where
  shouldn'tSCC D = ()
  {-# INLINE shouldn'tSCC #-}

hasSCC :: D -> ()
hasSCC D = ()

hasn'tSCC :: D -> ()
hasn'tSCC D = ()
{-# INLINE hasn'tSCC #-}

main :: IO ()
main = do
  print (hasSCC D)
  print (hasn'tSCC D)
  print (shouldn'tSCC D)

Compile and run the program with profiling:

ghc --make -prof -fprof-auto-top fprof-auto-top.hs
./fprof-auto-top +RTS -p

The profile fprof-auto-top.prof contains entries for hasSCC (expected) and shouldn'tSCC (unexpected); there is (correctly) no entry for hasn'tSCC.

I also compiled with -ddump-simpl to see that shouldn'tSCC unexpectedly has an scctick: fprof-auto-top.dump-simpl

Expected behavior

I expect that only hasSCC defined above will have an automatic SCC annotation. As it stands, there is apparently no way to inhibit instance methods from getting SCC annotations when using -fprof-auto-top.

Environment

• GHC version used: The Glorious Glasgow Haskell Compilation System, version 8.6.5

Optional:

• Operating System: NixOS 19.09, Linux 4.14.157
• System Architecture: x86_64-linux