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Impossible compilation with primitive operations (possibly unsafeCoerce#)

On the following code :

ulp#::Double#->Double# ulp# d=

let w=unsafeCoerce\# d Word64\#
e=(unsafeCoerce\# (uncheckedShiftRL64\# w 52\#)) `and#` 0x7ff\#\#
in
if e `gtWord#` 0x034\#\# then
unsafeCoerce\# (unsafeCoerce\# (e `minusWord#` (0x034\#\#)) `uncheckedShiftL64#` 52\#)
else
unsafeCoerce\# (1\#\# `uncheckedShiftL#` ((unsafeCoerce\# e) -\# 1\#))

GHC 6.12.1 returns :

ghc: panic! (the 'impossible' happened)

(GHC version 6.12.1 for i386-apple-darwin):

getRegister(x86) I64[BaseReg + 72]

Trac metadata
Trac field Value
Version 6.12.1
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture
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