Return the FPTOSINT_* value for the given types, or UNKNOWN_LIBCALL if there is none.
The FPTOSINT_* libcall for OpVT and RetVT, or UNKNOWN_LIBCALL if none exists.
| Name | Description |
|---|---|
| OpVT | Source floating-point value type. |
| RetVT | Destination signed-integer value type. |