[Bug rtl-optimization/95405] Unnecessary stores with std::optional

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95405

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-03-07
          Component|tree-optimization           |rtl-optimization
             Target|                            |x86_64-linux-gnu
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
On aarch64 we do the correct thing:
_Z3barv:
        stp     x29, x30, [sp, -32]!
        mov     x29, sp
        bl      _Z3foov
        tst     w1, 255
        csel    x0, x0, xzr, ne
        ldp     x29, x30, [sp], 32
        ret

So this is most likely an issue with how x86_64 implements stuff.

Confirmed for x86_64 though.