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From: "boris at kolpackov dot net" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug middle-end/98753] -Wfree-nonheap-object on unreachable code
 with -O0
Date: Fri, 29 Jan 2021 11:29:21 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98753

Boris Kolpackov <boris at kolpackov dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |boris at kolpackov dot net

--- Comment #11 from Boris Kolpackov <boris at kolpackov dot net> ---
I believe I am encountering a similar false positive so I will attach the t=
est
cases to this bug (but let me know if I should instead attach them to 54202=
 or
create a new bug). The attached test.cxx is a cleaned-up original code while
test-simplified.cxx is its further simplified version (thanks to Matthew
Krupcale for coming up with both):

g++ -O1 -c test.cxx=20

In member function =E2=80=98void small_allocator<T, N, B>::deallocate(void*,
std::size_t) [with T =3D f()::expr; long unsigned int N =3D 1; B =3D
small_allocator_buffer<f()::expr, 1>]=E2=80=99,
    inlined from =E2=80=98std::vector<_Tp, _Alloc>::pointer std::vector<_Tp,
_Alloc>::_M_allocate_and_copy(std::vector<_Tp, _Alloc>::size_type,
_ForwardIterator, _ForwardIterator) [with _ForwardIterator =3D const f()::e=
xpr*;
_Tp =3D f()::expr; _Alloc =3D small_allocator<f()::expr, 1,
small_allocator_buffer<f()::expr, 1> >]=E2=80=99 at
/home/boris/work/build2/tests/modules/gcc2/gcc-install/include/c++/11.0.0/b=
its/alloc_traits.h:341:23,
    inlined from =E2=80=98void std::vector<_Tp, _Alloc>::reserve(std::vecto=
r<_Tp,
_Alloc>::size_type) [with _Tp =3D f()::expr; _Alloc =3D small_allocator<f()=
::expr,
1, small_allocator_buffer<f()::expr, 1> >]=E2=80=99 at
/home/boris/work/build2/tests/modules/gcc2/gcc-install/include/c++/11.0.0/b=
its/vector.tcc:85:36,
    inlined from =E2=80=98void small_vector<T, N>::reserve(std::size_t) [wi=
th T =3D
f()::expr; long unsigned int N =3D 1]=E2=80=99 at test.cxx:234:26,
    inlined from =E2=80=98small_vector<T, N>::small_vector() [with T =3D f(=
)::expr; long
unsigned int N =3D 1]=E2=80=99 at test.cxx:163:15,
    inlined from =E2=80=98void f()=E2=80=99 at test.cxx:1472:27:
test.cxx:121:27: warning: =E2=80=98void operator delete(void*)=E2=80=99 cal=
led on unallocated
object =E2=80=98exprs=E2=80=99 [-Wfree-nonheap-object]=