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From: "foom at fuhm dot net" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/101836] __builtin_object_size(P->M, 1) where M is an
 array and the last member of a struct fails
Date: Wed, 06 Jul 2022 16:16:56 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101836

--- Comment #33 from James Y Knight <foom at fuhm dot net> ---
(In reply to qinzhao from comment #32)
> there is a Bugzilla that has been filed for GCC to request the same warni=
ng
> for GCC:
> https://gcc.gnu.org/bugzilla//show_bug.cgi?id=3D94428
>=20
> -Wzero-length-array

Great. Adding that flag, and eliminating the -fstrict-flex-arrays=3D3 optio=
n from
this proposal would be good.

> As suggested by Siddhesh in comment#23, -Wstrict-flex-arrays might be
> necessary to be added too, and=20
> -Wzero-length-array will be an alias to=20
> -Wstrict-flex-arrays=3D3

I don't understand what the -Wstrict-flex-arrays warning and its multiple
levels is proposed to actually do.

Is it supposed to warn on the structs that change behavior in the correspon=
ding
-fstrict-flex-array=3DLEVEL? But that would mean -Wstrict-flex-arrays=3D1 w=
ould
warn on any array at the end of a struct which has a size other than 0 or 1.
That's clearly not going to be actually practical...so perhaps you had
something else in mind?=