> I see. Though the code does not affect layout but only access "layout"
> for bitfields. I'm fine with fixing the issues we run into elsewhere,
> just the langhook is a possibility I had in mind from the start, in
> case frontends differ in their memory model for bitfields.
Understood. According to our internal testing, the issue we're discussing was
the last problem introduced by the bitfield change, and I think that using the
C/C++ model for C/C++-compatible bit fields is fine for GNAT.
May I apply the patch I posted? It boostrapped/regtested fine on x86-64/Linux.