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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/105329] [12/13 Regression] Bogus restrict
 warning when assigning 1-char string literal to std::string since
 r12-3347-g8af8abfbbace49e6
Date: Mon, 02 May 2022 12:57:39 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105329

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #10)
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D104336#c1 contains a worka=
round
> for libstdc++

Maybe

      _GLIBCXX20_CONSTEXPR
      basic_string&
      assign(const _CharT* __s)
      {
        __glibcxx_requires_string(__s);
        return _M_replace(size_type(0), this->size(), __s,
                          traits_type::length(__s));
      }

isn't the most efficient way to assign a string (constant) looking at
the complexity of _M_replace and its overlap checks (that we all expect
to be optimized away but which are not).  In fact the _M_disjunct check
isn't optimized because we cannot tell if the std::string storage
overlaps the constant pool ...=