[GHC] #10712: Regression: make TEST=exceptionsrun001 WAY=optasm is failing

[GHC]

#10712: Regression: make TEST=exceptionsrun001 WAY=optasm is failing
-------------------------------------+-------------------------------------
              Reporter:  thomie      |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  high        |         Milestone:  7.12.1
             Component:  Compiler    |           Version:  7.11
              Keywords:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
             Test Case:              |        Blocked By:
  base/tests/exceptionsrun001        |
              Blocking:              |   Related Tickets:
Differential Revisions:              |
-------------------------------------+-------------------------------------
 The following program, extracted from the test exceptionsrun001, should
 exit with exitcode 100. Instead, when compiled with `-O1`, it never gets
 past the ioTest and somehow manages to exit with exitcode 0.

 {{{
 {-# LANGUAGE ScopedTypeVariables #-}
 module Main where

 import Control.Exception
 import System.IO.Error
 import System.Exit

 main = do
   ioTest
   exitWith (ExitFailure 100)

 ioTest :: IO ()
 ioTest = (catch (ioError (userError "wibble"))
                 (\(e::IOException) -> return ())
 }}}

 I think this will require a git bisect:
 * last known good commit: 34bb4605d4ec5b131df57ca4c91d6840b7539194
 * first known bad commit: f83aab95f59ae9b29f22fc7924e050512229cb9c.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10712>
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