https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118329
--- Comment #8 from Georg-Johann Lay <gjl at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #0) > avr uses FRACTIONAL_INT_MODE while e.g. msp430 uses PARTIAL_INT_MODE, > don't remember the difference The comments in machmode.def propose that PARTIAL_INT_MODE defines a mode with the same size but a lower precision, whereas FRACTIONAL_INT_MODE defines a new mode with a smaller size (dunno if that implies that the new precision must be a multiple or 8?). One more difference is that PARTIAL_INT_MODE's new mode is in class PARTIAL_INT, whereas FRACTIONAL_INT_MODE's is in class INT. Though that's mostly guessing as the documentation is poor and incomplete.
