Continued work on 64-bit neon operations. The negdi2 seems to be more difficult than previously thought - vneg won't do it, and there's no way to encode either "0-reg" or "not(reg)+1", so I'm shelving that idea for the moment, and moving on to one_compldi2_neon, which ought to be straight forward.

Did the entire Linaro GCC release process, in the absence of Michael Hope, from source to announcement. The process didn't go as smoothly as I'd have liked, but I got through it, mostly. Hopefully Michael won't be travelling next time ...

Tried to figure out how to do 64-bit shifts using a QImode shift amount. This promised to eliminate the unnecessary zero-extends, but it doesn't work because neither iwmmxt or neon registers are permitted to hold QImode values (presumably changing this would have consequences elsewhere?). Annoyingly, it's also not possible to put SImode values in (most) neon registers, so I'm not sure quite how to optimize the values. More investigation required.