[Bug tree-optimization/57503] [6/7/8 Regression] Wrong extension of multiply operand

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57503

--- Comment #19 from Marc Glisse <glisse at gcc dot gnu.org> ---
Looking at the very first testcase in this PR, assuming 16-bit int, 129*255
overflows and is thus undefined behavior. Multiply by 255u if you want the
multiplication to happen safely in an unsigned type.