Optimize inlining small C functions and add -inline-cfuncs (#6815)

src/Verilator.cpp

@@ -63,6 +63,7 @@
 #include "V3Graph.h"
 #include "V3HierBlock.h"
 #include "V3Inline.h"
+#include "V3InlineCFuncs.h"
 #include "V3Inst.h"
 #include "V3Interface.h"
 #include "V3LibMap.h"
@@ -565,6 +566,11 @@ static void process() {
                 V3Reloop::reloopAll(v3Global.rootp());
             }
 
+            if (v3Global.opt.inlineCFuncs()) {
+                // Inline small CFuncs to reduce function call overhead
+                V3InlineCFuncs::inlineAll(v3Global.rootp());
+            }
+
             // Fix very deep expressions
             // Mark evaluation functions as member functions, if needed.
             V3Depth::depthAll(v3Global.rootp());