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From: "xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/110617] New: RFE: Add a diagnostic-only variant of
 nonnull attribute
Date: Mon, 10 Jul 2023 18:25:49 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Version: 14.0
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X-Bugzilla-Severity: enhancement
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110617

            Bug ID: 110617
           Summary: RFE: Add a diagnostic-only variant of nonnull
                    attribute
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: xry111 at gcc dot gnu.org
  Target Milestone: ---

Currently nonnull serves as both a diagnostic attribute and an optimization
attribute.  But sometimes we want only the effect for diagnostic, but not t=
he
effect for code generation.

For example, Glibc developers implements many functions as "crash the progr=
am
immediately if an unexpected NULL pointer is passed" [1].  So it would be
useful to make the potential crash detectable via -Wnonnull and/or
-Wanalyzer-null-argument.  However they don't like the nonnull attribute on=
 the
function prototype, because the nonnull attribute may cause the optimizer to
break their "immediately crash" design [2].

I'm not sure how to name this variant of nonnull precisely. (Maybe "hate_nu=
ll
or something?)=