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Re: [i386] Scalar DImode instructions on XMM registers


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


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