On Thu, 26 Nov 2020, Jakub Jelinek wrote:
> Hi!
>
> On Wed, Nov 25, 2020 at 12:26:17PM -0500, Jason Merrill wrote:
> > I think you want to check DECL_PADDING_P here; the C and C++ front ends set
> > it on unnamed bit-fields, and that's what is_empty_type looks at.
>
> While the above has been written in the context of __builtin_bit_cast patch,
> I think it applies to __builtin_clear_padding too.
>
> So this patch implements that. The C FE sets DECL_PADDING_P solely on the
> DECL_BIT_FIELD !DECL_NAME FIELD_DECLs, the C++ FE sets it on those and in
> another spot I haven't really figured out what it is about.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Richard.
> 2020-11-26 Jakub Jelinek <ja...@redhat.com>
>
> * gimple-fold.c (clear_padding_union): Ignore DECL_PADDING_P
> fields.
> (clear_padding_type): Ignore DECL_PADDING_P fields, rather than
> DECL_BIT_FIELD with NULL DECL_NAME.
>
> --- gcc/gimple-fold.c.jj 2020-11-25 10:37:44.997297061 +0100
> +++ gcc/gimple-fold.c 2020-11-25 18:45:04.380442914 +0100
> @@ -4327,7 +4327,7 @@ clear_padding_union (clear_padding_struc
> }
>
> for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
> - if (TREE_CODE (field) == FIELD_DECL)
> + if (TREE_CODE (field) == FIELD_DECL && !DECL_PADDING_P (field))
> {
> if (DECL_SIZE_UNIT (field) == NULL_TREE)
> {
> @@ -4455,13 +4455,11 @@ clear_padding_type (clear_padding_struct
> HOST_WIDE_INT cur_pos;
> cur_pos = 0;
> for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN
> (field))
> - if (TREE_CODE (field) == FIELD_DECL)
> + if (TREE_CODE (field) == FIELD_DECL && !DECL_PADDING_P (field))
> {
> tree ftype = TREE_TYPE (field);
> if (DECL_BIT_FIELD (field))
> {
> - if (DECL_NAME (field) == NULL_TREE)
> - continue;
> HOST_WIDE_INT fldsz = TYPE_PRECISION (ftype);
> if (fldsz == 0)
> continue;
>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imend
