[Bug c/47977] powerpc (-mcpu=8548) Wrong code for double operations in little endian mode

[froydnj at codesourcery dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47977

--- Comment #2 from froydnj at codesourcery dot com <froydnj at codesourcery dot com> 2011-03-03 16:51:18 UTC ---
On Thu, Mar 03, 2011 at 04:08:53PM +0000, m.lazzarotto at robox dot it wrote:
>         lwz 9,8(1)                      # What's the purpose ?
>         lwz 10,12(1)                    # What's the purpose ?
>         stw 9,8(1)                      # What's the purpose ?
>         stw 10,12(1)                    # What's the purpose ?

These are an artifact of the lower-subreg pass; the E500 bits contain
some logic to clean up spurious moves introduced by using E500
floating-point, but the lower-subreg pass stymies those bits of logic.

A separate bug for a (sub-)target-specific pass to clean those artifacts
up would be appropriate, but I don't think it's going to happen any time
soon.