[GHC] #13380: raiseIO# result looks wrong

[GHC]

#13380: raiseIO# result looks wrong
-------------------------------------+-------------------------------------
        Reporter:  dfeuer            |                Owner:  dfeuer
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:  Exceptions
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dfeuer):

 Oh, it seems I pasted the link above wrong. I meant to paste
 [https://perf.haskell.org/ghc/#revision/7b087aeba45a7a70a5553ef4c116ee67660423e8
 a link to the perf dashboard for that commit]. There were two significant
 changes in nofib runtimes.

 {{{
 test                    old     change  new
 nofib/time/k-nucleotide 5.338   + 4.95% 5.602 seconds
 nofib/time/lambda       1.095   - 3.2%  1.06  seconds
 }}}

 There was also an unfortunate increase in nofib sizes that I didn't notice
 before (gipeda did not flag it for some reason). The sizes went up by a
 little over 1% across the board. Ouch. I'm guessing this is because we
 lost the dead code elimination we previously had for

 {{{#!hs
 case raiseIO# e s of ...
 }}}

 Could we recover that by using some sort of special rule somewhere that
 rewrites

 {{{#!hs
 case raiseIO# e s of
   p -> ...
 }}}

 to `raiseIO# e s`? I could give it a shot if someone tells me where to put
 it.

 There were a few test suite allocation regressions, the largest of which
 were

 {{{
 tests/alloc/T10547   33561264  + 1.36%  34019072   bytes
 tests/alloc/T5837    51419384  + 1.27%  52074608   bytes
 tests/alloc/T12425   134735944 + 0.52%  135441336  bytes
 tests/alloc/T10858   267909584 + 0.49%  269215800  bytes
 tests/alloc/T13035   93847840  + 0.44%  94264440   bytes
 tests/alloc/T6048    109461504 + 0.38%  109873560  bytes
 tests/alloc/T13056   420744984 + 0.37%  422320424  bytes
 }}}

 I believe the right way to fix these is to go through any code in `base`
 that uses `throwIO` and make sure we manually force everything we want to.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13380#comment:13>
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