tests: fix dfflibmap test - false negative conflict multiple -liberty…

… vs enable inference

tests/techmap/dfflibmap.ys

@@ -64,14 +64,15 @@ select -assert-count 1 t:dffe
 select -assert-none t:dffn t:dffsr t:dffe t:$_NOT_ %% %n t:* %i
 
 design -load orig
-dfflibmap -prepare -liberty dfflibmap_dffn.lib -liberty dfflibmap_dffsr.lib
-dfflibmap -map-only -liberty dfflibmap_dffn.lib -liberty dfflibmap_dffsr.lib
+dfflibmap -prepare -liberty dfflibmap_dffn_dffe.lib -liberty dfflibmap_dffsr.lib
+dfflibmap -map-only -liberty dfflibmap_dffn_dffe.lib -liberty dfflibmap_dffsr.lib
 clean
 
-select -assert-count 4 t:$_NOT_
+select -assert-count 5 t:$_NOT_
 select -assert-count 1 t:dffn
+select -assert-count 1 t:dffe
 select -assert-count 4 t:dffsr
-select -assert-none t:dffn t:dffsr t:$_NOT_ %% %n t:* %i
+select -assert-none t:dffn t:dffsr t:dffe t:$_NOT_ %% %n t:* %i
 
 design -load orig
 dfflibmap -liberty dfflibmap.lib -dont_use *ffn

tests/techmap/dfflibmap_dffn_dffe.lib

@@ -0,0 +1,47 @@
+library(test) {
+  cell (dffn) {
+    area : 6;
+    ff("IQ", "IQN") {
+      next_state : "D";
+      clocked_on : "!CLK";
+    } 
+    pin(D) {
+      direction : input;
+    }
+    pin(CLK) {
+      direction : input;
+    }
+    pin(Q) {
+      direction: output;
+      function : "IQ";
+    }
+    pin(QN) {
+      direction: output;
+      function : "IQN";
+    } 
+  }
+  cell (dffe) {
+    area : 6;
+    ff("IQ", "IQN") {
+      next_state : "(D&EN) | (IQ&!EN)";
+      clocked_on : "!CLK";
+    }
+    pin(D) {
+      direction : input;
+    }
+    pin(EN) {
+      direction : input;
+    }
+    pin(CLK) {
+      direction : input;
+    }
+    pin(Q) {
+      direction: output;
+      function : "IQ";
+    }
+    pin(QN) {
+      direction: output;
+      function : "IQN";
+    }
+  }
+}