A working program reports <<loop>> when compiled with -O

If the attached module Trampoline.hs is compiled with no optimizations it works:

$ ghc --make Trampoline.hs   
[1 of 1] Compiling Main             ( Trampoline.hs, Trampoline.o )
Linking Trampoline ...
$ ./Trampoline 
...
((5,2),(1,2,6))
$ 

With optimizations on, it hangs:

$ ghc --make Trampoline.hs -O
[1 of 1] Compiling Main             ( Trampoline.hs, Trampoline.o )
Linking Trampoline ...
$ ./Trampoline 
bounce start
bounce end
liftOut
inject suspend
Trampoline: <<loop>>

That doesn't seem right. Oh, GHCi runs it with no problem as well.

Trac metadata

Trac field	Value
Version	6.10.4
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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