https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110503
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
>
> Oh and had:
> # RANGE [irange] int [-128, 127]
> _10 = (intD.6) _9;
> # RANGE [irange] int [0, 1] NONZERO 0x1
> _11 = 1 % _10;
>
> I wonder if we could optimize `1 % b` into just `b != 1` (since 1 % 0 is
> undefined) which will further reduce things here.
That does not change the size of the loop though and we are still left with:
size: 1 _10 = _9 == 1;
size: 0 _11 = (unsigned int) _10;
size: 1 _12 = -_11;
size: 2 if (_12 > 2)
But at least now we just need to optimize the above to just `if (_9 == 1)`
Something like:
(simplify
(gt (negative zero_one_value@0) INTEGER_CST@1)
(if (wi::to_wide (@1) >= 1 && TYPE_UNSIGNED (TREE_TYPE (@1)))
(ne @0 { build_zero_cst (TREE_TYPE (@1)); } )
(if (wi::to_wide (@1) >= 0 && !TYPE_UNSIGNED (TREE_TYPE (@1)))
(eq @0 { build_zero_cst (TREE_TYPE (@1)); } )
)
)
)
But I get the feeling this should be done in VRP instead of match ...
