[Bug tree-optimization/128306] `a - a` for real types where a is not a NaN can be assumed to have a range of `[0, +INF] +-NaN`

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128306

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
            Summary|`a - a` for real types      |`a - a` for real types
                   |where a is not a NaN can be |where a is not a NaN can be
                   |assumed to be >= 0          |assumed to have a range of
                   |                            |`[0, +INF] +-NaN`
   Last reconfirmed|                            |2026-10-30
     Ever confirmed|0                           |1

--- Comment #5 from Drea Pinski <pinskia at gcc dot gnu.org> ---
So that makes sense.  Now removing the subtraction is a generic trapping math
issue.  But the range can be done as `[-0.0, +INF] +-NaN` then and things will
just work.  This is easy to add I think.