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From: "subscriptions-gnu at vsbe dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/90844] New: Another case of missing use of uninitialized variable warning
Date: Tue, 11 Jun 2019 21:03:00 -0000 [thread overview]
Message-ID: <bug-90844-4@http.gcc.gnu.org/bugzilla/> (raw)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90844
Bug ID: 90844
Summary: Another case of missing use of uninitialized variable
warning
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: subscriptions-gnu at vsbe dot com
Target Milestone: ---
this is somewhat similar to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18501,
but a bit different. Here is the code to trigger the problem:
vvvvvvvvvvv try.c vvvvvvvvvvvvvvvvvvvvvvvvvvv
static int func1(int x) { return 1; }
static int func2(void)
{
int number;
if (func2() == 0) number += func1(0);
return number;
}
int main(int argc, char **argv)
{
int counter;
counter += func2();
return counter;
}
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Running on 4.19.28-2 x86_64 GNU/Linux, using compiler version
vvvvvvvvvvvvvvvvvvvvvvvvvvvv
arm-eabi-gcc -v
Using built-in specs.
COLLECT_GCC=/usr/local/google/home/vbendeb/new_projects/1grepo/chroot/opt/coreboot-sdk/bin/arm-eabi-gcc
COLLECT_LTO_WRAPPER=/usr/local/google/home/vbendeb/new_projects/1grepo/chroot/opt/coreboot-sdk/bin/../lib/gcc/arm-eabi/8.3.0/lto-wrapper
Target: arm-eabi
Configured with: ../gcc-8.3.0/configure --prefix=/opt/coreboot-sdk
--libexecdir=/opt/coreboot-sdk/lib --target=arm-eabi --disable-werror
--disable-shared --enable-lto --enable-plugins --enable-gold
--enable-ld=default --disable-libssp --disable-bootstrap --disable-nls
--disable-libquadmath --without-headers --disable-threads --enable-interwork
--enable-multilib --enable-targets=all --disable-libatomic --disable-libcc1
--disable-decimal-float --enable-languages=c,ada --with-system-zlib
--with-gmp=/var/tmp/portage/dev-embedded/coreboot-sdk-0.0.1-r74/work/coreboot-sdk-0.0.1/out/opt/coreboot-sdk
--with-mpfr=/var/tmp/portage/dev-embedded/coreboot-sdk-0.0.1-r74/work/coreboot-sdk-0.0.1/out/opt/coreboot-sdk
--with-mpc=/var/tmp/portage/dev-embedded/coreboot-sdk-0.0.1-r74/work/coreboot-sdk-0.0.1/out/opt/coreboot-sdk
--with-gnu-as --with-gnu-ld --with-pkgversion='coreboot toolchain v '
Thread model: single
gcc version 8.3.0 (coreboot toolchain v )
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The below invocation properly highlights two instance of the uninitialized
variable assignment:
$ arm-eabi-gcc -Wall -o try.o -c try.c
try.c: In function 'func2':
try.c:7:34: warning: 'number' may be used uninitialized in this function
[-Wmaybe-uninitialized]
if (func2() == 0) number += func1(0);
^~
try.c: In function 'main':
try.c:14:17: warning: 'counter' is used uninitialized in this function
[-Wuninitialized]
counter += func2();
^~
$
The following invocation triggers only one warning:
$ arm-eabi-gcc -Wall -Os -flto -o try.o -c try.c
try.c: In function 'main':
try.c:14:17: warning: 'counter' is used uninitialized in this function
[-Wuninitialized]
counter += func2();
^~
$
>From gcc-bugs-return-646368-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Jun 11 21:57:06 2019
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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/90397] Incompatibility with clang-tidy on std::variant
Date: Tue, 11 Jun 2019 21:57:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90397
--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
G++ allowed it because the mismatch was in a system header. If you use
-Wsystem-headers then GCC 9.1 gives a warning about it:
/xhome/jwakely/gcc/9.1.0/include/c++/9.1.0/variant: In instantiation of 'class
std::variant<A, B>':
var.cc:14:44: required from here
/xhome/jwakely/gcc/9.1.0/include/c++/9.1.0/variant:1559:34: warning:
declaration of 'template<long unsigned int _Np, class _Vp> constexpr
decltype(auto) std::__detail::__variant::__get(_Vp&&)' has a different
exception specifier [-Wsystem-headers]
1559 | friend constexpr decltype(auto) __detail::__variant::__get(_Vp&& __v);
| ^~~~~~~~
/xhome/jwakely/gcc/9.1.0/include/c++/9.1.0/variant:263:5: note: from previous
declaration 'template<long unsigned int _Np, class _Variant> constexpr
decltype(auto) std::__detail::__variant::__get(_Variant&&) noexcept'
263 | __get(_Variant&& __v) noexcept
| ^~~~~
If you use -pedantic-errors then you get an error.
>From gcc-bugs-return-646369-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Jun 11 22:04:46 2019
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From: "tkoenig at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/90744] [7/8/9/10 Regression] Bogus length for character temporaries passed to external procedures since r268992
Date: Tue, 11 Jun 2019 22:04:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90744
--- Comment #8 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
Author: tkoenig
Date: Tue Jun 11 22:04:10 2019
New Revision: 272173
URL: https://gcc.gnu.org/viewcvs?rev=272173&root=gcc&view=rev
Log:
2019-06-11 Thomas Koenig <tkoenig@gcc.gnu.org>
Tomáš Trnka <trnka@scm.com>
Backport from trunk
PR fortran/90744
* trans-types.c (get_formal_from_actual_arglist): Unset typespec
flags which make no sense for procedures without explicit
interface.
2019-06-11 Thomas Koenig <tkoenig@gcc.gnu.org>
Tomáš Trnka <trnka@scm.com>
Backport from trunk
PR fortran/90744
* gfortran.dg/deferred_character_33.f90: New test.
* gfortran.dg/deferred_character_33a.f90: New test.
Added:
branches/gcc-9-branch/gcc/testsuite/gfortran.dg/deferred_character_33.f90
branches/gcc-9-branch/gcc/testsuite/gfortran.dg/deferred_character_33a.f90
Modified:
branches/gcc-9-branch/gcc/fortran/ChangeLog
branches/gcc-9-branch/gcc/fortran/trans-types.c
branches/gcc-9-branch/gcc/testsuite/ChangeLog
>From gcc-bugs-return-646370-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Jun 11 22:26:51 2019
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From: "segher at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/90513] asm thunks do not work on PowerPC64/VxWorks (kernel mode)
Date: Tue, 11 Jun 2019 22:26:00 -0000
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--- Comment #19 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Also, please post proper patches, to the gcc-patches mailing list, as
detailed in <https://gcc.gnu.org/contribute.html>, if you want those
patches to be approved.
>From gcc-bugs-return-646371-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Jun 11 22:31:48 2019
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On Tue, Jun 11, 2019 at 10:25:58PM +0530, Umesh Kalappa wrote:
> We would like to know comments on the below proposed change ?
As I said in the PR, this is not a proper patch. Also, like Eric says
there, it does not do the right thing for many configurations.
Fix the loader, instead?
Segher
next reply other threads:[~2019-06-11 21:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 21:03 subscriptions-gnu at vsbe dot com [this message]
2021-04-15 22:55 ` [Bug middle-end/90844] missing -Wmaybe-uninitialized with -flto and optimization msebor at gcc dot gnu.org
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