(declare (type (integer -2 14) b))
(declare (ignorable b))
(ash (imagpart b) 57))
on PPC (and possibly on other platforms, but not on x86 at least) gives an error
during the emission of FAST-ASH-LEFT/FIXNUM=>FIXNUM as the assembler
attempts to stuff a too-large constant into the immediate field of a PPC instruction.
Either the VOP should be fixed or the compiler should be taught how to transform
this case away, paying particular attention to side-effects that might occur in the
arguments to ASH.
Confirmed for 1.0.22.