On 3/4/08, Richard Guenther <[EMAIL PROTECTED]> wrote: > I suggest to make sure that bit position and size are constants, the > object referenced is of integral type (BIT_FIELD_REF should not be > used as a way to circumvent aliasing) and the result type is of the > same type as the operand zero type (and not a bitfield type of the > referenced size -- in which case the BIT_FIELD_REF_UNSIGNED would > be useless). The result would then be properly extended according > to BIT_FIELD_REF_UNSIGNED.
I tried non constant bit position with BIT_FIELD_REF of vector types and it crashed in expand so I think this is the correct thing to do. Though it would be nice if we have a VEC_EXTRACT tree instead of overloading BIT_FIELD_REF for it that takes a non constant position so we can do better optimization there in some cases (yes people write code that extracts parts of vectors, trust me). -- Pinski
