Heap profiling with ghc and hp2ps and strict function application ($!) gives samples out of sequence (regression)

The following program generates an invalid .hp file when compiled with ghc 8.2.1 but it does not when using ghc 8.0.2.

{-# LANGUAGE ScopedTypeVariables #-}
module Main where

  eval :: forall a b. (a -> b -> b) -> b -> [a] -> b
  eval f b xs = load xs []
    where
      load :: [a] -> [a] -> b
      load [] stk          = unload b stk
      load (x:xs) stk      = load xs (x : stk)

      unload :: b -> [a] -> b
      unload  v []         = v
      unload  v (x  : stk) = unload ((f $! x) $! v) stk

  main :: IO ()
  main = print (eval (||) False (True : replicate 10000000 False))

If strict application (!) is substituted for normal application () or removed then the .hp generated file is correct.

For reproducing the error:

ghc -O2 --make -prof -fprof-auto Example.hs -fforce-recomp
./Example +RTS -hc
hp2ps -e8in -c Example.hp

It outputs:

hp2ps: Example.hp, line 43, samples out of sequence

Trac metadata

Trac field	Value
Version	8.2.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Runtime System
Test case
Differential revisions
BlockedBy
Related	#14006 (closed)
Blocking
CC
Operating system
Architecture