[Bug target/82580] Optimize comparisons for __int128 on x86-64

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82580

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
BTW, perhaps powerpc64, aarch64 or other targets could benefit from similar
approach.  Shall we clone this PR for those?