> I thought it was the other way round - that after Bernd's fixes (July > 2011) towards support for 40-bit integers, FRACTIONAL_INT_MODE worked > better than PARTIAL_INT_MODE.
Probably most accurate to say that both ways are not well supported. In general, I always have a hard time with anything that isn't a power-of-two size in gcc, because most maintainers have no reason to even consider such cases. There are even some fundamantal problems I've run into, for example... SIZE_TYPE is compared - with individual strcmp's! - against a fixed set of C types, instead of using some sort of table lookup to support non-power-of-two types. P*type modes are not stored in the modes table with *type modes, but the functions to get the "next bigger mode" blindly assumes that mode[N+1] is the next mode, which ignores partial int modes completely. Operations with 3-byte PSImode end up using BLKmode sometimes.
