Gate micro-timers behind verbose flag

[calewis]

Avoids clock calls in hot loops when not in verbose mode. Compile with -DABC_NO_TIMERS to turn off inner-loop timers entirely.

On i10.aig (b; rs -K 6 -N 2; rf; rw; rs -K 8 -N 2; rf -z; rw -z): verbose 0.103s, default 0.100s (-3.3%), -DABC_NO_TIMERS 0.099s (-3.8%).

[wjrforcyber]

Maybe a single choke point inside Abc_Clock() itself would avoid lots of repeated changes in the future? Since currently the changes only affect those mentioned optimisers. 🤔

[calewis]

Abc_Clock is also used in places that have timeouts so we can't just have a define that makes Abc_Clock return 0. Also having a way to avoid calling Abc_Clock when verbose mode is disabled saves a decent amount of time. Clock calls aren't free and the verbosity check helps a good bit to fix that.

[wjrforcyber]

Abc_Clock is also used in places that have timeouts so we can't just have a define that makes Abc_Clock return 0.

Yes, they are used in comparison and branches. Maybe it's just I see only a few of "comparison/branches" but a great amount of "measurement", so even manually do it I'll prefer modifying the former instead of the latter.

Also having a way to avoid calling Abc_Clock when verbose mode is disabled saves a decent amount of time. Clock calls aren't free and the verbosity check helps a good bit to fix that.

Fair point.