pattern shiftmul

state <SigSpec> shamt

match shift
	select shift->type.in($shift, $shiftx, $shr)
endmatch

code shamt
	shamt = port(shift, \B);
	if (shamt[GetSize(shamt)-1] == State::S0) {
		do {
			shamt.remove(GetSize(shamt)-1);
		} while (shamt[GetSize(shamt)-1] == State::S0);
	} else
	if (param(shift, \B_SIGNED).as_bool()) {
		reject;
	}
endcode

match mul
	select mul->type.in($mul)
	select port(mul, \A).is_fully_const() || port(mul, \B).is_fully_const()
	index <SigSpec> port(mul, \Y) === shamt
endmatch

code
	IdString const_factor_port = port(mul, \A).is_fully_const() ? \A : \B;
	int const_factor = port(mul, const_factor_port).as_int();
	if (GetSize(port(shift, \Y)) > const_factor)
		reject;
	log_dump(shift, shamt, mul, const_factor);
	reject;
endcode