+.It Fl f Ns Cm expressions-for-builtins
+Usually builtin-numbers are just immediate constants. With this flag
+expressions can be used, as long as they are compile-time constant.
+.Pp
+Example:
+.Bd -literal -offset indent
+void printA() = #1; // the usual way
+void printB() = #2-1; // with a constant expression
+.Ed
+.It Fl f Ns Cm return-assignments
+Enabiling this option will allow assigning values or expressions to the
+return keyword as if it were a local variable of the same type as the
+function's signature's return type.
+.Pp
+Example:
+.Bd -literal -offset indent
+float bar() { return 1024; }
+float fun() {
+ return = bar();
+ return; // returns value of bar
+}
+.Ed
+.It Fl f Ns Cm unsafe-varargs
+When passing on varargs to a different functions, this turns some
+static error cases into warnings. Like when the caller's varargs are
+restricted to a different type than the callee's parameter. Or a list
+of unrestricted varargs is passed into restricted varargs.
+.It Fl f Ns Cm typeless-stores
+Always use STORE_F, LOAD_F, STOREP_F when accessing scalar variables.
+This is somewhat incorrect assembly instruction use, but in all engines
+they do exactly the same. This makes disassembly output harder to read,
+breaks decompilers, but causes the output file to be better compressible.
+.It Fl f Ns Cm sort-operands
+In commutative instructions, always put the lower-numbered operand first.
+This shaves off 1 byte of entropy from all these instructions, reducing
+compressed size of the output file.
+.It Fl f Ns Cm emulate-state
+Emulate OP_STATE operations in code rather than using the instruction.
+The desired fps can be set via -state-fps=NUM, defaults to 10.
+Specifying \-state-fps implicitly sets this flag. Defaults to off in all
+standards.
+.It Fl f Ns Cm arithmetic-exceptions
+Turn on arithmetic exception tests in the compiler. In constant expressions
+which trigger exceptions like division by zero, overflow, underflow, etc,
+the following flag will produce diagnostics for what triggered that
+exception.