[GHC] #13604: ghci no longer loads dynamic .o files by default if they were built with -O

[GHC]

#13604: ghci no longer loads dynamic .o files by default if they were built with -O
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        Reporter:  George            |                Owner:  dfeuer
            Type:  bug               |               Status:  patch
        Priority:  highest           |            Milestone:  8.2.2
       Component:  Compiler          |              Version:  8.2.1-rc1
      Resolution:                    |             Keywords:
                                     |  RecompilationCheck
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D4123
       Wiki Page:                    |
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Comment (by elaforge):

 It feels like an odd approach.  The situation implied by -fignore-optim-
 changes is that I'm not passing the same flags, but I want to load '.o's
 anyway.  But from my point of view, I *am* passing the same flags, the
 problem is that ghci is filtering them out.  So with that new flag, it
 becomes: pass the same flags, ghci filters out some making them not the
 same, pass another flag that says ignore when some flags are not the same.
 We'll need another flag that does the same thing for -fhpc (as you
 mention) and then possibly in the future some more to ignore any other
 symptoms of ghci filtering out flags.  Doesn't it seem a bit convoluted?
 If I weren't following this thread, and ran into this problem, I'm not
 sure I'd be able to find all proper flags to get it to work.

 Compare that to making ghci no longer change the flags you pass, even if
 it can't implement them: it just works, no flags needed.  You could add
 one to suppress the warning about "ignoring some of your flags" but we
 have some general verbosity level stuff already.

 That said, I am following this thread, so I will know about the flags, so
 they (once you put in one for -fhpc of course) will fix my problem.  So
 aside from my worry that it seems overcomplicated, I'm in favor.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13604#comment:40>
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