[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 #39 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Segher Boessenkool from comment #38)
> You cannot put a const_int in a MODE_CC.  It is meaningless.

Reg 17 in

(insn 49 10 50 2 (parallel [
            (set (reg:CCC 17 flags)
                (ne:CCC (reg:SI 82 [ a.1_2 ])
                    (const_int 0 [0])))
            (set (reg:SI 92)
                (neg:SI (reg:SI 82 [ a.1_2 ])))
        ]) "107172.c":4:10 680 {*negsi_ccc_1}

becomes const_int 1 since a.1_2 is known non-zero.  Roger's patch simplifies
const_int in a MODE_CC properly.