On Wed, Nov 10, 2021 at 12:36:04PM +0100, Richard Biener wrote:
> > I'm afraid I forgot the DECL_FIELD_OFFSET vs. DECL_FIELD_BIT_OFFSET stuff
> > enough that I'm not sure what is the right fix for that case, maybe it would
> > work if we dropped the && TREE_CODE (DECL_FIELD_OFFSET (decl)) ==
> > INTEGER_CST
> > check and instead used:
> > - bitpos_int = wi::to_offset (DECL_FIELD_BIT_OFFSET (decl));
> > + if (TREE_CODE (DECL_FIELD_OFFSET (decl)) == INTEGER_CST)
> > + bitpos_int = wi::to_offset (bit_position (decl));
> > + else
> > + bitpos_int = wi::to_offset (DECL_FIELD_BIT_OFFSET (decl));
> > at the start and
> > - if (ctx->variant_part_offset == NULL_TREE)
> > + if (ctx->variant_part_offset == NULL_TREE
> > + && TREE_CODE (DECL_FIELD_OFFSET (decl)) == INTEGER_CST)
> > {
> > *cst_offset = object_offset_in_bytes.to_shwi ();
> > return NULL;
> > }
> > tree_result = wide_int_to_tree (sizetype, object_offset_in_bytes);
> > + if (TREE_CODE (DECL_FIELD_OFFSET (decl)) == INTEGER_CST)
> > + tree_result = size_binop (PLUS_EXPR, DECL_FIELD_OFFSET (decl),
> > + tree_result);
>
> that needs multiplication by BITS_PER_UNIT.
I don't think so.
>From bit_from_pos and byte_from_pos functions it is clear that
DECL_FIELD_OFFSET is in bytes and DECL_FIELD_BIT_OFFSET in bits.
And object_offset_in_bytes is in bytes too.
>
> > or so.
>
> Not sure if it's worth special-casing constant DECL_FIELD_OFFSET
> though, or whether the code can just work with DECL_FIELD_BIT_OFFSET
> and DECL_FIELD_OFFSET be always added.
It has certainly the advantage that it doesn't change anything for the
most common case (where DECL_FIELD_OFFSET is INTEGER_CST).
Jakub
