[GHC] #14901: dsrun004 fails with most ways

[GHC]

#14901: dsrun004 fails with most ways
-------------------------------------+-------------------------------------
           Reporter:  alpmestan      |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.5
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Incorrect result
  Unknown/Multiple                   |  at runtime
          Test Case:  dsrun004       |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 The `dsrun004` test doesn't seem to pass for a whole bunch of ways, as a
 recent `./validate --slow` (against yesterday's master) revealed.

 {{{#!py
 # the test options
 test('dsrun014', normal, compile_and_run, ['-fobject-code'])
 }}}

 {{{#!hs
 -- the haskell program we build & run
 {-# LANGUAGE UnboxedTuples #-}

 module Main where

 import Debug.Trace

 {-# NOINLINE f #-}
 f :: a -> b -> (# a,b #)
 f x y = x `seq` y `seq` (# x,y #)

 g :: Int -> Int -> Int
 g v w = case f v w of
           (# a,b #) -> a+b

 main = print (g (trace "one" 1) (trace "two" 2))
 -- The args should be evaluated in the right order!
 }}}

 {{{
 # the failing ways
 /tmp/ghctest-n4fi8zlk/test   spaces/./deSugar/should_run/dsrun014.run
 dsrun014 [bad stderr] (hpc)
 /tmp/ghctest-n4fi8zlk/test   spaces/./deSugar/should_run/dsrun014.run
 dsrun014 [bad stderr] (optasm)
 /tmp/ghctest-n4fi8zlk/test   spaces/./deSugar/should_run/dsrun014.run
 dsrun014 [bad stderr] (threaded2)
 /tmp/ghctest-n4fi8zlk/test   spaces/./deSugar/should_run/dsrun014.run
 dsrun014 [bad stderr] (dyn)
 /tmp/ghctest-n4fi8zlk/test   spaces/./deSugar/should_run/dsrun014.run
 dsrun014 [bad stderr] (optllvm)
 }}}

 With those 5 ways, the program's trace is `two` then `one` while with some
 other ways (like ghci or normal) we get (as expected by the testsuite)
 `one` first and `two` afterwards.

 I'm not sure whether the expectation is too strong or whether there's
 something fishy going on with those 5 ways.

 Simon, could you perhaps comment on this? Is this a "proper" bug?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14901>
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