http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58970
--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Bernd Edlinger from comment #10)
> but this should'nt be neccessary then?
>
> if (bitoffset > *bitpos)
> {
> HOST_WIDE_INT adjust = bitoffset - *bitpos;
> -
> gcc_assert ((adjust % BITS_PER_UNIT) == 0);
> - gcc_assert (*offset != NULL_TREE);
>
> *bitpos += adjust;
> - *offset
> - = size_binop (MINUS_EXPR, *offset, size_int (adjust / BITS_PER_UNIT));
> + if (*offset == NULL_TREE)
> + *offset = size_int (-adjust / BITS_PER_UNIT);
> + else
> + *offset
> + = size_binop (MINUS_EXPR, *offset, size_int (adjust / BITS_PER_UNIT));
> *bitstart = 0;
> }
Can you prove it isn't necessary? I mean, *bitpos could still be smaller than
bitoffset, even when not negative, say with some packed+aligned structures
containing bitfields or similar. NULL_TREE *offset is the same thing as zero
at that spot, just perhaps less efficient in that case, so I think if we can't
prove it will not be hit, it is easy to handle it.
