[Bug rtl-optimization/32629] missing CSE for constant in registers / inefficient memset

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=32629

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
We could also make $0 a not legitimate constant on x86... (and undo that late
with a peephole2)