[GHC] #15114: ghc 8.4.1 optimizes True to False
GHC
ghc-devs at haskell.org
Wed May 2 19:33:35 UTC 2018
#15114: ghc 8.4.1 optimizes True to False
-------------------------------------+-------------------------------------
Reporter: elaforge | Owner: (none)
Type: bug | Status: new
Priority: normal | Milestone: 8.6.1
Component: Compiler | Version: 8.4.1
Keywords: | Operating System: Unknown/Multiple
Architecture: | Type of failure: None/Unknown
Unknown/Multiple |
Test Case: | Blocked By:
Blocking: | Related Tickets:
Differential Rev(s): | Wiki Page:
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Ok, here's a short module:
{{{#!hs
import qualified Control.Exception as Exception
main :: IO ()
main = do
unserialize
putStrLn "all is well"
unserialize :: IO Char
unserialize =
if definitelyTrue
then do
return 'a'
else do
Exception.evaluate (error "wrong place")
{-# NOINLINE definitelyTrue #-}
definitelyTrue :: Bool
definitelyTrue = True
}}}
When compiled with -O on 8.4.1, this should print "wrong place".
Without -O, or with 8.4.2, or if True can be inlined, or without
evaluate, all is well. I can reproduce this on OS X 10.13.4.
This could be related to a known bug with Exception.evaluate in 8.4.1:
#3930
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15114>
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