Optimizations change result of div for Word

Here is test case

import Data.Word

main :: IO ()
main = do
  print $ (maxBound :: Word) `div` 101

And result of execution

$ ghc -fforce-recomp -O2 --make reduce.hs && ./reduce
[1 of 1] Compiling Main             ( reduce.hs, reduce.o )
Linking reduce ...
2891661149
@{debian:0}~/qqq/mwc $ ghc -fforce-recomp --make reduce.hs && ./reduce
[1 of 1] Compiling Main             ( reduce.hs, reduce.o )
Linking reduce ...
42524428

Bug is only present on 32-bit systems. It goes away if rewrite rules are disable with -fno-enable-rewrite-rules or anything but maxBound is used as first argument or second argument is forced to be a funcion argument. So it could be bug in constant folding.

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
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