------- Comment #7 from steven at gcc dot gnu dot org 2008-04-16 08:59 ------- I agree with Paolo in comment #6. One purpose of the lower-subreg path was to allow backends to *not* define insns that it doesn't have. The expanders will generate inline code for such patterns at expand time, with sets to subregs. Before GCC had lower-subreg, this would lead to awful code, but now that we split the subregs out to pseudos it ought to work just fine.
Sadly, even i386 still hasn't been modified to benefit from this work... -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35860
