opt: add test for loop
opt: add test for loop

dinfuehr/dora,dinfuehr/dora,riginding/dora,dinfuehr/dora,riginding/dora,dinfuehr/dora,riginding/dora,dinfuehr/dora,riginding/dora,dinfuehr/dora,riginding/dora,riginding/dora,riginding/dora