[Bug tree-optimization/109901] Optimization opportunity: ((((a) > (b)) - ((a) < (b))) < 0) -> ((a) < (b))

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109901

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=101807,
                   |                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=101703

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.

Basically the rule is
bool0 - bool1 < 0 -> !bool0 & bool1 -> bool1 < bool0
bool0 - bool1 == -1 -> !bool0 & bool1 -> bool1 < bool0
bool0 - bool1 == 0 -> !bool0 & !bool1 -> !(bool0 | bool1)
bool0 - bool1 == 1 -> bool0 & !bool1 -> bool0 < bool1
bool0 - bool1 > 0 -> bool0 & !bool1 -> bool0 < bool1
and see if that reduces.

Note 
!bool0 & bool1 -> bool1 < bool0 (see PR 101807 for the opposite there)