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

[ubizjak at gmail dot com]

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

--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
Created attachment 42393
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42393&action=edit
Prototype patch

Attached patch generates:

foobar:
        cmpq    %rdx, %rdi
        sbbq    %rcx, %rsi
        setb    %al
        ret