TimeQuest Constraints Automation

Hi Josy,

Thanks to your response I realized what I was missing!

If I add a synthesis keep constraint inside the mux_2to1.vhd component to the combinatorial inputs, i.e.,

attribute keep : boolean;
attribute keep of sel : signal is true;
attribute keep of d   : signal is true;

Then the SDC netlist preserves these nodes, and get_pins will return matches to the sel, d[0], and d[1] combinatorial input signals, eg.,

tcl> set col * *d*}]
tcl> query_collection -report -all $col
u1|sel~buf0|combout
u1|d~buf0|combout
u1|d~buf0|combout
u1|sel~buf0|datad
pin_sel~input|o
u1|d~buf0|datad
pin_d~input|o
u1|d~buf0|datac
pin_d~input|o
pin_sel~input|i
pin_d~input|i
pin_d~input|i
\g1:u2|d~buf0|combout
\g1:u2|d~buf0|combout
\g1:u2|sel~buf0|combout
\g1:u2|d~buf0|datac
\g1:u2|d~buf0|datad
\g1:u2|sel~buf0|datac
u3|u1|d~buf0|combout
u3|u1|d~buf0|combout
u3|u1|sel~buf0|combout
u3|u1|d~buf0|datad
u3|u1|d~buf0|datad
u3|u1|sel~buf0|datac
u3|u2|sel~buf0|combout
u3|u2|d~buf0|combout
u3|u2|d~buf0|combout
u3|u2|sel~buf0|datac
u3|u2|d~buf0|datad
u3|u2|d~buf0|datac
u4|\g1:0:u1|sel~buf0|combout
u4|\g1:0:u1|d~buf0|combout
u4|\g1:0:u1|d~buf0|combout
u4|\g1:0:u1|sel~buf0|datad
u4|\g1:0:u1|d~buf0|datad
u4|\g1:0:u1|d~buf0|datac
u4|\g1:1:u1|sel~buf0|combout
u4|\g1:1:u1|d~buf0|combout
u4|\g1:1:u1|d~buf0|combout
u4|\g1:1:u1|sel~buf0|datad
u4|\g1:1:u1|d~buf0|datad
u4|\g1:1:u1|d~buf0|datad
u4|\g1:2:u1|d~buf0|combout
u4|\g1:2:u1|d~buf0|combout
u4|\g1:2:u1|sel~buf0|combout
u4|\g1:2:u1|d~buf0|datad
u4|\g1:2:u1|d~buf0|datad
u4|\g1:2:u1|sel~buf0|datad
u4|\g1:3:u1|sel~buf0|combout
u4|\g1:3:u1|d~buf0|combout
u4|\g1:3:u1|d~buf0|combout
u4|\g1:3:u1|sel~buf0|datac
u4|\g1:3:u1|d~buf0|datac
u4|\g1:3:u1|d~buf0|datac

and now a get_fanins call can be used on sel, d[0], or d[1] to find the input mapping, eg.,

tcl> tmq_find_comb_input sel
u1|sel~buf0|combout                      connects to pin_sel
u1|sel~buf0|datad                        connects to pin_sel
\g1:u2|sel~buf0|combout                  connects to pin_sel
\g1:u2|sel~buf0|datac                    connects to pin_sel
 
u3|u1|sel~buf0|combout                   connects to pin_sel
u3|u1|sel~buf0|datac                     connects to pin_sel
  
u3|u2|sel~buf0|combout                   connects to pin_sel
u3|u2|sel~buf0|datac                     connects to pin_sel
  
u4|\g1:0:u1|sel~buf0|combout             connects to pin_sel
u4|\g1:0:u1|sel~buf0|datad               connects to pin_sel
u4|\g1:1:u1|sel~buf0|combout             connects to pin_sel
u4|\g1:1:u1|sel~buf0|datad               connects to pin_sel
  
u4|\g1:2:u1|sel~buf0|combout             connects to pin_sel
u4|\g1:2:u1|sel~buf0|datad               connects to pin_sel
  
u4|\g1:3:u1|sel~buf0|combout             connects to pin_sel
u4|\g1:3:u1|sel~buf0|datac               connects to pin_sel
  
tcl> tmq_find_comb_input d
u1|d~buf0|combout                     connects to pin_d
u1|d~buf0|datac                       connects to pin_d
 
\g1:u2|d~buf0|combout                 connects to pin_d
\g1:u2|d~buf0|datac                   connects to pin_d
  
u3|u1|d~buf0|combout                  connects to pin_d
u3|u1|d~buf0|datad                    connects to pin_d
  
u3|u2|d~buf0|combout                  connects to pin_d
u3|u2|d~buf0|datad                    connects to pin_d
 
u4|\g1:0:u1|d~buf0|combout            connects to pin_d
u4|\g1:0:u1|d~buf0|datac              connects to pin_d
  
u4|\g1:1:u1|d~buf0|combout            connects to pin_d
u4|\g1:1:u1|d~buf0|datad              connects to pin_d
  
u4|\g1:2:u1|d~buf0|combout            connects to pin_d
u4|\g1:2:u1|d~buf0|datad              connects to pin_d
  
u4|\g1:3:u1|d~buf0|combout            connects to pin_d
u4|\g1:3:u1|d~buf0|datac              connects to pin_d
tcl> tmq_find_comb_input d
u1|d~buf0|combout                     connects to pin_d
u1|d~buf0|datad                       connects to pin_d
 
\g1:u2|d~buf0|combout                 connects to pin_d
\g1:u2|d~buf0|datad                   connects to pin_d
 
u3|u1|d~buf0|combout                  connects to pin_d
u3|u1|d~buf0|datad                    connects to pin_d
 
u3|u2|d~buf0|combout                  connects to pin_d
u3|u2|d~buf0|datac                    connects to pin_d
  
u4|\g1:0:u1|d~buf0|combout            connects to pin_d
u4|\g1:0:u1|d~buf0|datad              connects to pin_d
  
u4|\g1:1:u1|d~buf0|combout            connects to pin_d
u4|\g1:1:u1|d~buf0|datad              connects to pin_d
  
u4|\g1:2:u1|d~buf0|combout            connects to pin_d
u4|\g1:2:u1|d~buf0|datad              connects to pin_d
  
u4|\g1:3:u1|d~buf0|combout            connects to pin_d
u4|\g1:3:u1|d~buf0|datac              connects to pin_d

where here I've called get_fanins on both of the nodes matched by get_pins, just to check that both paths map back to a common input, and to show that the dataa/datab/datac/datad mapping to each instance differs.

Cheers,

Dave

NOTE: I updated the zip file above with the latest version.