Kenneth Zadeck <zad...@naturalbridge.com> writes: > Would those that know, (or even those that are just generally vocal) be > willing to support a change rtl.texi for sign_extract (and by > implication, zero_extract) from > > If @var{loc} is in memory, its mode must be a single-byte integer mode. > If @var{loc} is in a register, the mode to use is specified by the > operand of the @code{insv} or @code{extv} pattern > (@pxref{Standard Names}) and is usually a full-word integer mode, > which is the default if none is specified. > > to a version that explicitly prohibits the use of a mode longer than a word? > > The back ends do not appear to support this anyway.
I guess the obvious counterexample would be a processor which supported vector registers and supported bitfield operations on such registers. I don't know of any such processors. The restriction would probably be fine in practice, but why do you want to make it? Ian