[Bug target/85572] faster code for absolute value of __v2di

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85572

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 44042
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44042&action=edit
gcc8-pr85572.patch

Untested fix.