[Bug middle-end/120434] GCC uses signed extend (movsxd) for known positive variables rather than zero extend 'mov'

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120434

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Interesting clang/LLVM only does this for -Os and only on x86_64. I am agreeing
it should be done at -O2 because it is almost always better to zero extend
rather than sign extend on MOST if not all targets.