[Bug tree-optimization/127452] [17 Regression] forwprop generates 128bit multiplication even if not supported by the target

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127452

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 65617
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=65617&action=edit
testcase

Testcase, the modulo_poly_coeffs_loop / multiply_poly_scalar_coeffmod_loop
inlined into main() are the interesting loops to be vectorized, the
multiply_uint64_hw64 worker shows the early forwprop transform.