[Bug target/122390] sbcs should be used instead of sbc/cmp

[ubizjak at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122390

--- Comment #5 from Uroš Bizjak <ubizjak at gmail dot com> ---
Created attachment 62711
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62711&action=edit
Additional x86 target patch

This patch compiles (gcc -O2) the testacse from Comment #4 to:

000000000000000 <g>:
   0:   39 d7                   cmp    %edx,%edi
   2:   19 ce                   sbb    %ecx,%esi
   4:   0f 92 c0                setb   %al
   7:   c3                      ret

instead of:

0000000000000000 <g>:
   0:   39 d7                   cmp    %edx,%edi
   2:   89 f0                   mov    %esi,%eax
   4:   19 c8                   sbb    %ecx,%eax
   6:   39 c6                   cmp    %eax,%esi
   8:   0f 92 c0                setb   %al
   b:   c3                      ret