If non-null INS is the insn table entry.
Otherwise INSN_VALUE is examined to compute it.
LENGTH is the number of bits in INSN_VALUE if known, otherwise 0.
- INDICES is a pointer to a buffer of MAX_OPERANDS ints to be filled in.
+ INDICES is a pointer to a buffer of MAX_OPERAND_INSTANCES ints to be filled
+ in.
The result a pointer to the insn table entry, or NULL if the instruction
wasn't recognized. */