[Bug rtl-optimization/118755] [15 Regression] ccmp_3.c fails on aarch64

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118755

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> I think the first thing we could do is (from fwprop1):
> ```
> propagating insn 13 into insn 14, replacing:
> (set (reg:SI 103 [ _3 ])
>     (reg/v:SI 104 [ <retval> ]))
> successfully matched this instruction to *zero_extendqisi2_aarch64:
> (set (reg:SI 103 [ _3 ])
>     (zero_extend:SI (subreg:QI (reg:SI 108) 0)))
> original cost = 4 (weighted: 4.000000), replacement cost = 4 (weighted:
> 4.000000); rejecting replacement
> change not profitable
> propagating insn 13 into insn 15, replacing:
> (set (reg:SI 109)
>     (and:SI (reg/v:SI 104 [ <retval> ])
>         (const_int 1 [0x1])))
> failed to match this instruction:
> (set (reg:SI 109)
>     (zero_extend:SI (and:QI (subreg:QI (reg:SI 108) 0)
>             (const_int 1 [0x1]))))
> ```
> That should just be simplified to:
> (set (reg:SI 109) (and:SI (reg:SI 108) (const_int 1 [0x1])))
> 
> Though I am not sure this will fix everything.

It does not fix it but it is still a good thing to do.