> There's a usecase for lower-bounded types such as int_least32_t, where the compiler may choose a larger type if it offers better performance.
If you're looking for the best performances you shouldn't use leastX types, you should use fastX types (e.g. int_fast32_t for the "fastest integer type available in the implementation, that has at least 32 bits").
The difference between "leastX" and "fastX" is that "leastX" is the smallest type in the implementation which has at least X bits. So if the implementation has 16, 32 and 64b ints and is a 32b architecture, least8 would give you a 16b int but fast8 might give you a 32b one.
If you're looking for the best performances you shouldn't use leastX types, you should use fastX types (e.g. int_fast32_t for the "fastest integer type available in the implementation, that has at least 32 bits").
The difference between "leastX" and "fastX" is that "leastX" is the smallest type in the implementation which has at least X bits. So if the implementation has 16, 32 and 64b ints and is a 32b architecture, least8 would give you a 16b int but fast8 might give you a 32b one.