[Bug tree-optimization/110949] ((cast)cmp) - 1 should be tranformed into -(cast)cmp` where cmp` is the inverse of cmp

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110949

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-08-21
           Severity|normal                      |enhancement
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot 
gnu.org

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note the RTL level does this optimization:
Trying 8 -> 9:
    8: r99:SI=cc:CC==0
      REG_DEAD cc:CC
    9: r97:SI=r99:SI-0x1
      REG_DEAD r99:SI
Successfully matched this instruction:
(set (reg:SI 97 [ _8D.4420 ])
    (neg:SI (ne:SI (reg:CC 66 cc)
            (const_int 0 [0]))))