Constrain valid arguments to BIT_FIELD_REF

[Alexandre Oliva]

On Mar  9, 2008, Eric Botcazou <ebotcazou@adacore.com> wrote:

>> I meant Ada can have non-integral members that are do not occupy an
>> integral number of bytes.

> Right, but the middle-end shouldn't need to touch them globally, the
> front-end is supposed to break up the accesses.

My point is that the front-end could just generate BIT_FIELD_REF,
without having to extract integral-typed words from the struct-typed
object to then be able to apply BIT_FIELD_REF on them, and then go
back to put the modified value back in place.

-- 
Alexandre Oliva         http://www.lsd.ic.unicamp.br/~oliva/
FSF Latin America Board Member         http://www.fsfla.org/
Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}