read_liberty latch inference disabled by default

Signed-off-by: James Cherry <cherry@parallaxsw.com>

doc/ChangeLog.txt

@@ -17,6 +17,10 @@ pin activities for power analysis.
 
 The report_cell command has been removed; use report_instance.
 
+The read_liberty command latch inference (see OpenSTA.pdf) is now disabled by default.
+The -no_latch_infer flag is deprecated.
+To enable latch inference, use the -infer_latches flag.
+
 Release 2.3.3 2022/09/24
 -------------------------
 

liberty/Liberty.cc

@@ -1301,8 +1301,7 @@ LibertyCell::finish(bool infer_latches,
   makeTimingArcPortMaps();
   findDefaultCondArcs();
   makeLatchEnables(report, debug);
-  if (infer_latches
-      && !interface_timing_)
+  if (infer_latches)
     inferLatchRoles(debug);
 }
 

tcl/Liberty.tcl

@@ -23,13 +23,16 @@ define_cmd_args "read_liberty" \
 
 proc_redirect read_liberty {
   parse_key_args "read_liberty" args keys {-corner} \
-    flags {-min -max -no_latch_infer}
+    flags {-min -max -no_latch_infer -infer_latches}
   check_argc_eq1 "read_liberty" $args
 
   set filename [file nativename [lindex $args 0]]
   set corner [parse_corner keys]
   set min_max [parse_min_max_all_flags flags]
-  set infer_latches [expr ![info exists flags(-no_latch_infer)]]
+  if { [info exists flags(-no_latch_infer)] } {
+    sta_warn 625 "-no_latch_infer is deprecated."
+  }
+  set infer_latches [info exists flags(-infer_latches)]
   read_liberty_cmd $filename $corner $min_max $infer_latches
 }