9.1. Avoid Implicit Data Type Conversions
Using this option helps you avoid inadvertently having conversions between double-precision and single-precision values when double-precision variables are not needed. In FPGAs, using double-precision variables can negatively affect the data transfer rate, the latency, and resource utilization of your component.
Additionally, constants are treated as signed int or signed double. If you want efficient operations with narrower constants, cast constants to other, narrower data types like ac_int<> or float.
If you use the Algorithmic C (AC) arbitrary precision datatypes, pay attention to the type propagation rules.