[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 #48 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Roger Sayle from comment #47)
> I really don't believe that using UNSPEC here is the correct way to go, but
> it appears to be the (only?) approach that Segher is prepared to approve. 
> Hohum.

I wish we could avoid UNSPEC.