[Bug target/117864] uadd_with_carry could be improved for aarch64

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117864

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |easyhack

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note x86_64 produces:
```
uadd_with_carry:
        addb    $-1, %dl
        adcl    %esi, %edi
        movl    %edi, (%rcx)
        setc    %al
        ret
```

That is because x86_64 implements the uaddc5/usubc5 optabs and GCC produces:
```
  _15 = (unsigned int) c_8(D);
  _16 = .UADDC (a_5(D), b_6(D), _15);
  _3 = REALPART_EXPR <_16>;
  *out_12(D) = _3;
  _10 = IMAGPART_EXPR <_16>;
  _14 = (_Bool) _10;
```

So this should be an easy change for some one new that wants to work on aarch64
backend to do.