[GHC] #9315: Weird change in allocation numbers of T9203

[GHC]

#9315: Weird change in allocation numbers of T9203
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              Reporter:  nomeata     |             Owner:  simonmar
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Runtime     |           Version:  7.9
  System                             |          Keywords:
            Resolution:              |  Operating System:  Unknown/Multiple
Differential Revisions:              |   Type of failure:  None/Unknown
          Architecture:              |         Test Case:
  Unknown/Multiple                   |          Blocking:
            Difficulty:  Unknown     |
            Blocked By:              |
       Related Tickets:              |
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Comment (by nomeata):

 Sigh. Both `Foreign.Storable` and `GHC.Fingerprint` have (with
 `-dsuppress-unique`) identical core. Also `Data.Typeable.Internal` where
 the ticky diffs show the same number of calls to
 `base:Data.Typeable.Internal.$fTypeableks_$ctypeRep#`, but a different
 allocation count.... hah! but only when I copy the ghc invocation from one
 host to the other, not if if I run `make` there, which for some reason
 passes `-O2` when compiling `Data.Typeable.Internal`....

 So the problem is as follows: Invocation of `validate` and the usual
 `devel2` settings in `mk/build.mk` have `GhcLibHcOpts    += -O -dcore-
 lint`, while the default in the absence of everything is `-O2` (in `in
 GhcLibHcOpts=-O2`). And sometime that makes a difference...

 Clearly, this needs to be consolidated. What are the settings used to
 actually build the releases? `-O` or `-O2`? The appropriate one needs to
 be used in `validate`, otherwise these tests are not very useful. And then
 people will have to use the same flags in their `mk/build.mk` or learn to
 ignore benchmark results from such a tree.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9315#comment:5>
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