What should I do to see this block as register?

Hi,

I want to know timing of specific path between registers to implement asynchronous circuit.

Following block is seen as register, so that it is exist in matches list in Name Finder in Timing Analyzer. So, I can know the timing information between this register and another register.

lut_input lut_in1 (a, wa);
lut_input lut_in2 (b, wb);
lut_input lut_in3 (y, wy);
lut_input lut_in4 (l, wl);
 
lut_output lut_o ((~wl & wy) | (wl & (wa | wb)), y);

However, following block is not seen as register. What should I do to see this block as register?

lut_input lut_in1 (l, wl);
lut_input lut_in2 (q, wq);
lut_input lut_in3 (s, ws);
lut_input lut_in4 (r, wr);
lut_input lut_in5 (mr, wmr);
 
lut_output lut_o ((~wl & wq) | (wl & ((~ws & wr & wmr) | (wq & ws) | (wq & ws & wr & wmr))), q);

I’m using Cyclone V GT.