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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c/98503] [11 regression] -Warray-bounds false positive with
 global variables at -O2 since r11-3306-g3f9a497d1b0dd9da
Date: Tue, 05 Jan 2021 17:31:24 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98503

--- Comment #10 from Martin Sebor <msebor at gcc dot gnu.org> ---
The main purpose of the "partly outside" warning is to detect reads/writes =
that
cross the trailing array boundary.  Those typically come up when a "typeles=
s"
buffer (either char array or one allocated by a function like malloc) is us=
ed
to store a sequence of heterogeneous elements.  Besides these bugs the warn=
ing
also detects other kinds of invalid accesses that span the boundary, like in
comment #0.  The access there in invalid for a different reason than the us=
ual
-Warray-bounds, so issuing a warning that's controlled by a different option
would be appropriate (-Wstrict-aliasing seems like a good fit).  It's somet=
hing
we have discussed doing but it's not at the top my to do list.  Making it
conditional on -fstrict-aliasing might be worth considering as well.=