[i386] Scalar DImode instructions on XMM registers

[Marc Glisse]

On Fri, 24 Apr 2015, Uros Bizjak wrote:

> Please try to generate paradoxical subreg (V2DImode subreg of V1DImode
> pseudo). IIRC, there is some functionality in the compiler that is
> able to tell if the highpart of the paradoxical register is zeroed.

Those are not currently legal (I tried to change that)
https://gcc.gnu.org/ml/gcc-patches/2013-03/msg00745.html
https://gcc.gnu.org/ml/gcc-patches/2014-06/msg00769.html

In this case, a subreg:V2DI of DImode should work.

-- 
Marc Glisse