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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/103483] context-sensitive ranges change triggers
 stringop-overread
Date: Tue, 30 Nov 2021 12:11:38 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103483

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=3D103332
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-11-30

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> I think the warning is correct really.

It's wrong.

> as if
> d is a+1000 it is undefined. Without inlining there is no way to know if d
> is any value.

It's able to inline the size of the buffer all the way down to the
char_traits::copy call, but isn't able to inline the length argument as wel=
l.

If it can't use the compile-time constant length that is present in the cod=
e,
it shouldn't bother doing these checks. The middle-end should not assume all
code is wrong by default. These bogus stringop warnings in std::string are
getting out of hand.

See also PR103332 and others.=