On Tue, Aug 16, 2022 at 2:16 PM Nathan Sidwell <nat...@acm.org> wrote: > > On 8/15/22 10:03, Richard Biener wrote: > > On Mon, Aug 15, 2022 at 3:29 PM Nathan Sidwell via Gcc-patches > > <gcc-patches@gcc.gnu.org> wrote: > >> > >> On 8/2/22 10:44, Qing Zhao wrote: > >>> Hi, Nathan, > >>> > >>> I am adding a new bitfield “decl_not_flexarray” in “tree_decl_common” > >>> (gcc/tree-core.h) for the new gcc feature -fstrict-flex-arrays. > >>> > >>> ==== > >>> diff --git a/gcc/tree-core.h b/gcc/tree-core.h > >>> index ea9f281f1cc..458c6e6ceea 100644 > >>> --- a/gcc/tree-core.h > >>> +++ b/gcc/tree-core.h > >>> @@ -1813,7 +1813,10 @@ struct GTY(()) tree_decl_common { > >>> TYPE_WARN_IF_NOT_ALIGN. */ > >>> unsigned int warn_if_not_align : 6; > >>> > >>> - /* 14 bits unused. */ > >>> + /* In FIELD_DECL, this is DECL_NOT_FLEXARRAY. */ > >>> + unsigned int decl_not_flexarray : 1; > >> > >> Is it possible to invert the meaning here -- set the flag if it /IS/ a > >> flexible array? negated flags can be confusing, and I see your patch > >> sets it to '!is_flexible_array (...)' anyway? > > > > The issue is it's consumed by the middle-end but set by a single (or two) > > frontends and the conservative setting is having the bit not set. That > > works > > nicely together with touching just the frontends that want stricter behavior > > than currently ... > > Makes sense, but is the comment incomplete? I'm guessing this flag is > for FIELD_DECLs /of array type/, and not just any old FIELD_DECL? After > all a field of type int is not a flexible array, but presumably doesn't > need this flag setting?
Yes, the docs should be more complete in tree.h on the actual DECL_NOT_FLEXARRAY definition. Richard. > nathan > > -- > Nathan Sidwell