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From: "tlange at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug analyzer/107882] [13 Regression] ICE in get_last_bit_offset, at analyzer/store.h:255 since 13-2582-g0ea5e3f4542832b8
Date: Mon, 28 Nov 2022 19:47:09 +0000	[thread overview]
Message-ID: <bug-107882-4-vXK0XkP7Q0@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-107882-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107882

--- Comment #2 from Tim Lange <tlange at gcc dot gnu.org> ---
Created attachment 53979
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53979&action=edit
patch for pr107882

I think the assertion here uncovered a bug. Currently, if the OTHER parameter
of bit_range::contains_p is empty (i.e. of size zero), contains_p calls
get_last_bit_offset, which result is only defined for non-empty ranges. Before
r13-2582-g0ea5e3f4542832b8, the contains_p check was inconsistent, e.g. for
(offset 1, size 1) and (offset 1, size 0), but true for (offset 0, size 2) and
(offset 1, size 0).

Not sure what the "right" fix is, as empty ranges sorta feel unnatural.
Treating [i, 0] as a subset of (k, n) if k <= i <= k+n seems somewhat
reasonable.

  parent reply	other threads:[~2022-11-28 19:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-26 19:36 [Bug analyzer/107882] New: [13 Regression] ICE in get_last_bit_offset, at analyzer/store.h:255 asolokha at gmx dot com
2022-11-28  6:49 ` [Bug analyzer/107882] " marxin at gcc dot gnu.org
2022-11-28  7:38 ` [Bug analyzer/107882] [13 Regression] ICE in get_last_bit_offset, at analyzer/store.h:255 since 13-2582-g0ea5e3f4542832b8 rguenth at gcc dot gnu.org
2022-11-28 19:47 ` tlange at gcc dot gnu.org [this message]
2022-12-06 20:53 ` dmalcolm at gcc dot gnu.org
2022-12-06 23:25 ` cvs-commit at gcc dot gnu.org
2022-12-06 23:33 ` dmalcolm at gcc dot gnu.org

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