> Hmm, yeah. Or something like
>
> Index: expr.c
> ===================================================================
> --- expr.c (revision 186082)
> +++ expr.c (working copy)
> @@ -4490,8 +4490,8 @@ get_bit_range (unsigned HOST_WIDE_INT *b
> bitoffset += (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
> - tree_low_cst (DECL_FIELD_BIT_OFFSET (repr), 1));
>
> - *bitstart = bitpos - bitoffset;
> - *bitend = *bitstart + tree_low_cst (DECL_SIZE (repr), 1) - 1;
> + *bitstart = bitpos < (HOST_WIDE_INT) bitoffset ? 0 : bitpos -
> bitoffset;
> + *bitend = bitpos + tree_low_cst (DECL_SIZE (repr), 1) - bitoffset - 1;
> }
>
> /* Returns true if the MEM_REF REF refers to an object that does not
>
> which conservatively truncates the bitrange.
What do you think about allowing get_bit_range to adjust offset and bitpos?
tem = get_inner_reference (to, &bitsize, &bitpos, &offset, &mode1,
&unsignedp, &volatilep, true);
if (TREE_CODE (to) == COMPONENT_REF
&& DECL_BIT_FIELD_TYPE (TREE_OPERAND (to, 1)))
get_bit_range (&bitregion_start, &bitregion_end, &offset, &bitpos, to);
so as to have a really non-negative bitregion_start/bitregion_end? It would
assert that offset is already non-null in that case.
--
Eric Botcazou
