[Bug tree-optimization/117776] [12/13/14/15 Regression] Missed optimization/vectorization opportunity (adding a even/odd check to an accumulator)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117776

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I have a patch but I need to write up a few testcases.

Basically I modified case for `(convert (convert` where the inner and outer
types were nop conversion to allow for the outer conversion to be greater than
the inner one. and then we canonicalize like I mentioned in comment #3.