Is it really true that "Jump threading, though, can- not be implemented in standard C."? Surely, each computed goto: goto *labels[*vpc++]; can be replaced

Is it really true that "Jump threading, though, can- not be implemented in standard C."? Surely, each computed goto: goto *labels[*vpc++]; can be replaced with a full copy of the switch: switch (*vpc++) { case OP_ADD: goto ADD; case OP_SUB: goto SUB; } ..and hopefully the compiler will replace the entries for the cases in the switch's jump table with the goto targets.