[Bug tree-optimization/104116] Optimize {FLOOR,CEIL,ROUND}_{DIV,MOD}_EXPR in tree-vect-patterns.cc

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104116

--- Comment #5 from Avinash Jayakar <avinashd at gcc dot gnu.org> ---
Created attachment 62265
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62265&action=edit
Proposed patch for vectorized floor mod implementation

Currently implemented only the floor mod operator using the following logic
input: x %[fl] y

output: 
...
vec_r = x % y (using the existing logic)
vec_cond = (x ^ y) & ( vec_r < 0)
vec_add_for_signed = vec_cond ? (y) : 0
result = vec_r + vec_add_for_signed

I tested with the same test case for fortran,
function arr_modulo(a)
  integer(kind=4) :: a(1024)
  a(:) = modulo (a(:), 39)
end function

With different values, it works properly. I will test a few more cases.

But I wanted to know if heading in the right direction.