Intel® C++ Compiler 16.0 User and Reference Guide
In cases where more than one data type can be used for a variable, consider selecting the data types based on the following hierarchy, listed from most to least efficient:
char
short
int
long
long long
float
double
long double
In an arithmetic expression, you should avoid mixing integer and floating-point data.
You can use integer data types (int, int long, etc.) in loops to improve floating point performance. Convert the data type to integer data types, process the data, then convert the data to the old type.