[Bug target/107172] [13 Regression] wrong code with "-O1 -ftree-vrp" on x86_64-linux-gnu since r13-1268-g8c99e307b20c502e

[hjl.tools at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107172

--- Comment #13 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Segher Boessenkool from comment #12)
> 
> To determine the semantics of this piece of RTL you need to see the setter(s)
> of reg 17 feeding this use.  In this case, the setter was
>   (set (reg:CCC 17)
>        (ne:CCC (reg:SI 82)
>                (const_int 0 [0])))
> which has no meaning for a use that uses "ltu".

What should a valid setter look like?  It should set reg 17 in CCC mode if
reg 82 in SI mode isn't 0.