On Tue, 5 Sep 2017, Richard Biener wrote: > don't have any BITS_PER_UNIT != 8 port (we had c4x). I'm not > sure what constraints we have on CHAR_TYPE_SIZE vs. BITS_PER_UNIT, > or for what port it would make sense to have differing values.
BITS_PER_UNIT = size of QImode = unit that target hardware addresses count in. CHAR_TYPE_SIZE = size of target char in the C ABI. sizeof (char) is always 1 by definition, but in principle you could have an architecture where the addressable unit at the hardware level is smaller than C char. CHAR_TYPE_SIZE must always be a multiple of BITS_PER_UNIT, and CHAR_TYPE_SIZE != BITS_PER_UNIT is probably even more bitrotten (I don't know if we've ever had such a port) than BITS_PER_UNIT != 8. -- Joseph S. Myers jos...@codesourcery.com
