[Bug c++/96117] New: Cannot mix c++11-style and GCC-style attributes
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96117
Bug ID: 96117
Summary: Cannot mix c++11-style and GCC-style attributes
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
```
struct __attribute__((visibility("default"))) [[deprecated("a message")]] A1
{
};
struct __attribute__((__deprecated__("a message")))
__attribute__((visibility("default"))) A2
{
};
```
A EXPORT macro containing a GCC-style visibility attribute (generated by CMake)
and another macro containing a c++11-style macro can not be used to decorate a
class.
https://godbolt.org/z/qHxr6s
[Bug c++/92914] New: Hidden visibility incompatible with extern'd specialized explicit template instantiations
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92914
Bug ID: 92914
Summary: Hidden visibility incompatible with extern'd
specialized explicit template instantiations
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
I'm trying to use hidden visibility with a library which is already used with
MSVC. It uses exported explicit template specializations.
mylib.h:-
#pragma once
#if _MSC_VER
# ifdef mylib_EXPORTS
#define MYLIB_EXPORT __declspec(dllexport)
# else
#define MYLIB_EXPORT __declspec(dllimport)
# endif
#else
# ifdef mylib_EXPORTS
#define MYLIB_EXPORT __attribute__((visibility("default")))
# else
#define MYLIB_EXPORT
# endif
#endif
template
class Templ
{
public:
T getNum() const;
T getAnotherNum() const;
};
#ifdef SPECIALIZE_INT
template<> MYLIB_EXPORT int Templ::getNum() const;
#endif
#ifndef mylib_EXPORTS
extern template class Templ;
extern template class Templ;
#endif
-
mylib.cpp-
#include "mylib.h"
template
T Templ::getNum() const
{
return 7;
}
template
T Templ::getAnotherNum() const
{
return 5;
}
#ifdef SPECIALIZE_INT
template<>
int Templ::getNum() const
{
return 42;
}
#endif
template class MYLIB_EXPORT Templ;
template class MYLIB_EXPORT Templ;
-
main.cpp--
#include "mylib.h"
#include
int main()
{
Templ ti;
Templ tf;
std::cout
<< ti.getNum() << " -- " << ti.getAnotherNum()
<< tf.getNum() << " -- " << tf.getAnotherNum() << std::endl;
return 0;
}
-
build.sh--
#!/bin/sh
set -x
COMPILE_DRIVER=g++
COMPILE_DRIVER=clang++
$COMPILE_DRIVER -Dmylib_EXPORTS -fPIC -fvisibility=hidden
-fvisibility-inlines-hidden -o mylib.$COMPILE_DRIVER.o -c ../mylib.cpp
$COMPILE_DRIVER -fPIC -Wl,--no-undefined -shared -o libmylib.so
mylib.$COMPILE_DRIVER.o
$COMPILE_DRIVER -fvisibility=hidden -fvisibility-inlines-hidden -o
main.$COMPILE_DRIVER.o -c ../main.cpp
$COMPILE_DRIVER main.$COMPILE_DRIVER.o -o myexe -Wl,-rpath,$PWD libmylib.so
# Compile with SPECIALIZE_INT defined:
$COMPILE_DRIVER -DSPECIALIZE_INT -Dmylib_EXPORTS -fPIC -fvisibility=hidden
-fvisibility-inlines-hidden -o mylib.$COMPILE_DRIVER.o -c ../mylib.cpp
$COMPILE_DRIVER -fPIC -Wl,--no-undefined -shared -o libmylib.so
mylib.$COMPILE_DRIVER.o
$COMPILE_DRIVER -DSPECIALIZE_INT -fvisibility=hidden
-fvisibility-inlines-hidden -o main.$COMPILE_DRIVER.o -c ../main.cpp
$COMPILE_DRIVER main.$COMPILE_DRIVER.o -o myexe -Wl,-rpath,$PWD libmylib.so
---
clang ---
+ clang++ -Dmylib_EXPORTS -fPIC -fvisibility=hidden -fvisibility-inlines-hidden
-o mylib.clang++.o -c ../mylib.cpp
+ clang++ -fPIC -Wl,--no-undefined -shared -o libmylib.so mylib.clang++.o
+ clang++ -fvisibility=hidden -fvisibility-inlines-hidden -o main.clang++.o -c
../main.cpp
+ clang++ main.clang++.o -o myexe
-Wl,-rpath,/home/stephen/dev/src/playground/cpp/build libmylib.so
+ clang++ -DSPECIALIZE_INT -Dmylib_EXPORTS -fPIC -fvisibility=hidden
-fvisibility-inlines-hidden -o mylib.clang++.o -c ../mylib.cpp
+ clang++ -fPIC -Wl,--no-undefined -shared -o libmylib.so mylib.clang++.o
+ clang++ -DSPECIALIZE_INT -fvisibility=hidden -fvisibility-inlines-hidden -o
main.clang++.o -c ../main.cpp
+ clang++ main.clang++.o -o myexe
-Wl,-rpath,/home/stephen/dev/src/playground/cpp/build libmylib.so
---
While this works with clang above, it does not work with GCC:
gcc ---
+ g++ -Dmylib_EXPORTS -fPIC -fvisibility=hidden -fvisibility-inlines-hidden -o
mylib.g++.o -c ../mylib.cpp
+ g++ -fPIC -Wl,--no-undefined -shared -o libmylib.so mylib.g++.o
+ g++ -fvisibility=hidden -fvisibility-inlines-hidden -o main.g++.o -c
../main.cpp
+ g++ main.g++.o -o myexe -Wl,-rpath,/home/stephen/dev/src/playground/cpp/build
libmylib.so
+ g++ -DSPECIALIZE_INT -Dmylib_EXPORTS -fPIC -fvisibility=hidden
-fvisibility-inlines-hidden -o mylib.g++.o -c ../mylib.cpp
../mylib.cpp:24:29: warning: type attributes ignored after type is already
defined [-Wattributes]
template class MYLIB_EXPORT Templ;
^~
+ g++ -fPIC -Wl,--no-undefined -shared -o libmylib.so mylib.g++.o
+ g++ -DSPECIALIZE_INT -fvisibility=hidden -fvisibility-inlines-hidden -o
main.g++.o -c ../main.cpp
+ g++ main.g++.o -o myexe -Wl,-rpath,/home/stephen/dev/src/playground/cpp/build
libmylib.so
main.g++.o: In function `main':
main.cpp:(.text+0x4c): undefined reference to `Templ::getAnotherNum()
const'
collect2: error: ld returned 1 exit status
---
[Bug c++/92914] Hidden visibility incompatible with extern'd specialized explicit template instantiations
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92914 --- Comment #1 from Stephen --- www.open-std.org/jtc1/sc22AC/wg21/docs/papers/2017/p0537r0.html may be related to this too.
[Bug c++/92914] Hidden visibility incompatible with extern'd specialized explicit template instantiations
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92914 --- Comment #2 from Stephen --- Also: stephen@j5:~/dev/src/playground/cpp/build$ nm mylib.g++.o | c++filt W Templ::getAnotherNum() const W Templ::getNum() const W Templ::getAnotherNum() const T Templ::getNum() const stephen@j5:~/dev/src/playground/cpp/build$ nm mylib.clang++.o | c++filt r .LCPI2_0 0004 r .LCPI3_0 W Templ::getAnotherNum() const W Templ::getNum() const W Templ::getAnotherNum() const T Templ::getNum() const
[Bug c++/92914] Hidden visibility incompatible with extern'd specialized explicit template instantiations
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92914 --- Comment #3 from Stephen --- Also, I tried to follow what I think was indicated in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56328 in that I forward declared the specialization in the header.
[Bug c++/92914] Hidden visibility incompatible with extern'd specialized explicit template instantiations
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92914 --- Comment #4 from Stephen --- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55347 is also related.
[Bug c++/55183] New: GCC 4.8 constexpr is too permissive
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55183 Bug #: 55183 Summary: GCC 4.8 constexpr is too permissive Classification: Unclassified Product: gcc Version: 4.8.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassig...@gcc.gnu.org ReportedBy: steve...@gmail.com In the second patch set here uploaded by my colleague: https://codereview.qt-project.org/#change,33290 GCC 4.8 was too permissive in its handling of constexpr compared to GCC 4.6 and clang. I don't know how to create a minimal testcase for this issue, but wanted to file it in case it can be fixed before 4.8 is released.
[Bug c++/55183] GCC 4.8 constexpr is too permissive
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55183 --- Comment #5 from Stephen 2012-11-03 10:48:02 UTC --- Thanks for the information. The issue is indeed about use of reinterpret_cast in a constexpr method. The consensus, according to bug 55039, is that this should not be supported. There is also a lot of mention of 'the other PR'. Am I missing something, or is GCC being non-strict by still supporting this? Is there a stricter mode where this and other extensions are not available (for writing portable code)?
[Bug c++/54086] New: GCC should allow constexpr and const together
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54086
Bug #: 54086
Summary: GCC should allow constexpr and const together
Classification: Unclassified
Product: gcc
Version: 4.6.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: steve...@gmail.com
GCC and Clang differ in how they handle this code. Clang compiles it, but GCC
does not:
#include
static constexpr const char Data[] = {
'D', 'A', 'T', 'A',
};
static constexpr const char *data_func() { return Data; }
int main(int argc, char **argv)
{
char c = 'T';
switch(c)
{
case *data_func():
std::cout << "GOT A D" << std::endl;
break;
case *(data_func() + 2):
std::cout << "GOT A T" << std::endl;
}
}
$ clang++ --version
clang version 3.2
Target: x86_64-unknown-linux-gnu
Thread model: posix
$ g++ -dumpversion
4.6.1
$ g++ main.cpp -std=c++0x
main.cpp:163:48: error: both ‘const’ and ‘constexpr’ cannot be used here
http://thread.gmane.org/gmane.comp.compilers.clang.devel/22984
Thanks,
[Bug c++/56071] New: noexcept with template and private ctor fails
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56071
Bug #: 56071
Summary: noexcept with template and private ctor fails
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: steve...@gmail.com
$ g++ --version
g++ (Ubuntu/Linaro 4.7.2-2ubuntu1) 4.7.2
The following code is accepted by clang++, but not g++:
class B
{
template friend struct A;
private:
B() {}
~B() {}
};
template
struct A
{
T t;
B b;
A() noexcept(noexcept(B())) {}
};
#define BREAK
struct C {
A delegate;
C()
#ifdef BREAK
noexcept(noexcept(A()))
#endif
{ }
};
int main() {return 0;}
If the #define BREAK is commented out, it is accepted by g++ too. Making A not
a template type also makes g++ accept it.
[Bug c++/56071] friend class template cannot access private constructor in exception-specification
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56071
--- Comment #2 from Stephen 2013-01-22 01:44:19 UTC
---
Interestingly, add variadic templates to the mix and it compiles:
class B
{
template friend struct A;
private:
B(int, char) {}
~B() {}
};
template
struct A
{
T t;
template
A(Args&&... args) noexcept(noexcept(T(std::forward(args)...)))
: t(std::forward(args)...)
{}
};
struct C {
A delegate;
template
C(Args&&... args)
noexcept(noexcept(A(std::forward(args)...)))
: delegate(std::forward(args)...)
{ }
};
[Bug c++/56071] friend class template cannot access private constructor in exception-specification
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56071 --- Comment #3 from Stephen 2013-01-22 08:41:02 UTC --- clang has other issues relating to this. Something to maybe add unit tests for if they don't exist already: http://thread.gmane.org/gmane.comp.compilers.clang.devel/27226
[Bug c++/56071] friend class template cannot access private constructor in exception-specification
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56071 --- Comment #7 from Stephen 2013-01-22 17:28:14 UTC --- Thank you!
[Bug c++/70636] New: Link failure when C++ brace initialization is used
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70636
Bug ID: 70636
Summary: Link failure when C++ brace initialization is used
Product: gcc
Version: 5.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
$ g++ --version
g++ (Ubuntu 5.2.1-22ubuntu2) 5.2.1 20151010
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ cat brace-init.cpp
#include
#include
class Expression
{
public:
std::vector args;
};
Expression getExpr(const Expression& def = {})
{
return def;
}
int main()
{
auto a = getExpr();
// auto a = getExpr({});
}
$ g++ brace-init.cpp -std=c++11 -v
Using built-in specs.
COLLECT_GCC=/usr/bin/g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/5/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 5.2.1-22ubuntu2'
--with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-5 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib
--with-tune=generic --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 5.2.1 20151010 (Ubuntu 5.2.1-22ubuntu2)
COLLECT_GCC_OPTIONS='-std=c++11' '-v' '-shared-libgcc' '-mtune=generic'
'-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/5/cc1plus -quiet -v -imultiarch x86_64-linux-gnu
-D_GNU_SOURCE brace-init.cpp -quiet -dumpbase brace-init.cpp -mtune=generic
-march=x86-64 -auxbase brace-init -std=c++11 -version -fstack-protector-strong
-Wformat -Wformat-security -o /tmp/ccsM0fgs.s
GNU C++11 (Ubuntu 5.2.1-22ubuntu2) version 5.2.1 20151010 (x86_64-linux-gnu)
compiled by GNU C version 5.2.1 20151010, GMP version 6.0.0, MPFR
version 3.1.3, MPC version 1.0.3
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/5"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/5
/usr/include/x86_64-linux-gnu/c++/5
/usr/include/c++/5/backward
/usr/lib/gcc/x86_64-linux-gnu/5/include
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/5/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
GNU C++11 (Ubuntu 5.2.1-22ubuntu2) version 5.2.1 20151010 (x86_64-linux-gnu)
compiled by GNU C version 5.2.1 20151010, GMP version 6.0.0, MPFR
version 3.1.3, MPC version 1.0.3
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 5ed623d6fe11f4bcc1afee70f77e33b0
COLLECT_GCC_OPTIONS='-std=c++11' '-v' '-shared-libgcc' '-mtune=generic'
'-march=x86-64'
as -v --64 -o /tmp/cc7GSdPa.o /tmp/ccsM0fgs.s
GNU assembler version 2.25.1 (x86_64-linux-gnu) using BFD version (GNU Binutils
for Ubuntu) 2.25.1
COMPILER_PATH=/usr/lib/gcc/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/x86_64-linux-gnu/5/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../../lib/:/lib/x86_64-linux-gnu/:/lib/../lib/:/usr/lib/x86_64-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-linux-gnu/5/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-std=c++11' '-v' '-shared-libgcc' '-mtune=generic'
'-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/5/collect2 -plugin
/usr/lib/gcc/x86_64-linux-gnu/5/liblto_plugin.so
-plugin-opt=/usr/lib/gcc/x
[Bug c++/70637] New: Ambiguity error invoking a constructor with double brace initialization
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70637
Bug ID: 70637
Summary: Ambiguity error invoking a constructor with double
brace initialization
Product: gcc
Version: 5.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
$ g++ --version
g++ (Ubuntu 5.2.1-22ubuntu2) 5.2.1 20151010
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ g++ double-braces.cpp -std=c++11
double-braces.cpp: In function ‘int main()’:
double-braces.cpp:16:20: error: call of overloaded ‘SomeClass()’ is ambiguous
SomeClass sc({{}});
^
double-braces.cpp:7:12: note: candidate:
SomeClass::SomeClass(std::vector >)
explicit SomeClass(std::vector> samples)
^
double-braces.cpp:4:7: note: candidate: SomeClass::SomeClass(const SomeClass&)
class SomeClass
^
double-braces.cpp:4:7: note: candidate: SomeClass::SomeClass(SomeClass&&)
$ cat double-braces.cpp
#include
class SomeClass
{
public:
explicit SomeClass(std::vector> samples)
: mSamples(std::move(samples))
{
}
std::vector> mSamples;
};
int main()
{
SomeClass sc({{}});
}
[Bug libstdc++/65085] New: Move-assigned empty string corrupt with -D_GLIBCXX_USE_CXX11_ABI=1
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65085
Bug ID: 65085
Summary: Move-assigned empty string corrupt with
-D_GLIBCXX_USE_CXX11_ABI=1
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
GCC 5.0 generates corrupt CMake binaries currently:
http://thread.gmane.org/gmane.comp.programming.tools.cmake.devel/12392/focus=12420
The cause seems to be between the new ABI and moving an empty std::string:
stephen@hal:~/dev/src/playground/cpp{master}$
/home/stephen/dev/prefix/bin/g++-5.0 -v -std=gnu++11 membug.cpp
-D_GLIBCXX_USE_CXX11_ABI=1 -g
Using built-in specs.
COLLECT_GCC=/home/stephen/dev/prefix/bin/g++-5.0
COLLECT_LTO_WRAPPER=/home/stephen/dev/prefix/libexec/gcc/x86_64-unknown-linux-gnu/5.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../../../src/gcc/configure --prefix=/home/stephen/dev/prefix
--enable-languages=c,c++ --program-suffix=-5.0 --enable-checking=release
--with-system-zlib
Thread model: posix
gcc version 5.0.0 20150130 (experimental) (GCC)
COLLECT_GCC_OPTIONS='-v' '-std=gnu++11' '-D' '_GLIBCXX_USE_CXX11_ABI=1' '-g'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
/home/stephen/dev/prefix/libexec/gcc/x86_64-unknown-linux-gnu/5.0.0/cc1plus
-quiet -v -imultiarch x86_64-linux-gnu -D_GNU_SOURCE -D
_GLIBCXX_USE_CXX11_ABI=1 membug.cpp -quiet -dumpbase membug.cpp -mtune=generic
-march=x86-64 -auxbase membug -g -std=gnu++11 -version -o /tmp/ccruY1vz.s
GNU C++11 (GCC) version 5.0.0 20150130 (experimental)
(x86_64-unknown-linux-gnu)
compiled by GNU C version 5.0.0 20150130 (experimental), GMP version
6.0.0, MPFR version 3.1.2-p3, MPC version 1.0.2
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/home/stephen/dev/prefix/lib/gcc/x86_64-unknown-linux-gnu/5.0.0/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/home/stephen/dev/prefix/lib/gcc/x86_64-unknown-linux-gnu/5.0.0/../../include/c++/5.0.0
/home/stephen/dev/prefix/lib/gcc/x86_64-unknown-linux-gnu/5.0.0/../../include/c++/5.0.0/x86_64-unknown-linux-gnu
/home/stephen/dev/prefix/lib/gcc/x86_64-unknown-linux-gnu/5.0.0/../../include/c++/5.0.0/backward
/home/stephen/dev/prefix/lib/gcc/x86_64-unknown-linux-gnu/5.0.0/include
/usr/local/include
/home/stephen/dev/prefix/include
/home/stephen/dev/prefix/lib/gcc/x86_64-unknown-linux-gnu/5.0.0/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
GNU C++11 (GCC) version 5.0.0 20150130 (experimental)
(x86_64-unknown-linux-gnu)
compiled by GNU C version 5.0.0 20150130 (experimental), GMP version
6.0.0, MPFR version 3.1.2-p3, MPC version 1.0.2
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 017a5c35f0da909f1ce909a8ebb21479
COLLECT_GCC_OPTIONS='-v' '-std=gnu++11' '-D' '_GLIBCXX_USE_CXX11_ABI=1' '-g'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
as -v --64 -o /tmp/ccA64A8Z.o /tmp/ccruY1vz.s
GNU assembler version 2.24.51 (x86_64-linux-gnu) using BFD version (GNU
Binutils for Ubuntu) 2.24.90.20141014
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[Bug c++/108385] New: false positive -Wfree-nonheap-object
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108385
Bug ID: 108385
Summary: false positive -Wfree-nonheap-object
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
Sorry I was not able to reduce this further. Changing almost anything makes the
bug no-longer reproduce:
```
#include
#include
#include
class DataType {
public:
DataType() {
}
DataType get() const;
private:
double v = 0.0;
char values[41];
};
class ptrType {
public:
DataType someMethod() const {
DataType t;
t = t.get();
return t;
}
};
class AnotherDataType {
public:
typedef uint32_t size_type;
AnotherDataType() : _size(0), _data(new double[0]) {}
explicit AnotherDataType(size_type size) : _size(size), _data(new
double[size]) {}
virtual ~AnotherDataType() { delete[] _data; }
uint32_t size() const { return _size; }
double& operator()(size_type i) { return _data[i]; }
AnotherDataType get(const AnotherDataType& b) const
{
AnotherDataType c(size());
auto aItr = _data;
auto cItr = c.begin();
auto endp = _data + _size;
for (; aItr != endp; ++aItr, ++cItr) {
(*cItr) = (*aItr);
}
return c;
}
double sum() const {
double sum = *_data;
auto aItr = _data;
for (; aItr != _data + _size; ++aItr) {
sum = (*aItr);
}
return sum;
}
double* begin() { return _data; }
private:
size_type _size;
double* _data;
};
AnotherDataType anotherMethod(const ptrType* ptrType1) {
ptrType1->someMethod();
return {};
}
struct otherStruct {
const ptrType* ptrType1;
std::vector q1;
};
static double minF(otherStruct* params) {
auto err = anotherMethod(params->ptrType1);
return (err.get(err)).sum();
}
struct someStruct {
double (*f)(otherStruct* params);
otherStruct* params;
};
void foo(someStruct function) {
std::vector v;
minF(function.params);
}
void why() {
someStruct func;
func.f = &minF;
foo(func);
}
```
Godbolt link: https://godbolt.org/z/nqvsezj49
[Bug c++/108416] New: False positive -Wdangling-pointer
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108416
Bug ID: 108416
Summary: False positive -Wdangling-pointer
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
```
#include
class HoldsNonOwning {
public:
void reset(int* nonOwning) {
mNonOwning = nonOwning;
}
int compute(int input)
{
if (!mNonOwning)
{
return -1;
}
return input * *mNonOwning;
}
int* mNonOwning;
};
class HolderTest {
public:
HoldsNonOwning holder;
int compute();
};
int HolderTest::compute() {
int nonOwning = 2;
holder.reset(&nonOwning);
int i = holder.compute(42);
// If we uncomment this we don't get the warning
// std::cout << i << "\n";
return i;
}
int main(int, char**)
{
HolderTest ht;
int i = ht.compute();
std::cout << i << "\n";
return 0;
}
```
The -Wdangling-pointer gets triggered on this reasonable code. The pointer is
non-owning.
[Bug c++/108499] New: False positive -Warray-bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108499
Bug ID: 108499
Summary: False positive -Warray-bounds
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
```
#include
class MyStruct
{
public:
std::vector const& refAccessor();
std::size_t getSize();
};
void emitsWarning()
{
MyStruct params;
auto unusedThing = params.refAccessor();
(void)unusedThing;
auto const theSize = params.getSize();
std::vector initialVelocities(theSize, 0.0);
initialVelocities.back() = 6;
std::vector initialJoints(theSize, 0.0);
initialJoints.back() = 5;
}
```
-Werror=array-bounds -O2
```
: In function 'void emitsWarning()':
:20:27: error: array subscript -1 is outside array bounds of 'double
[1152921504606846975]' [-Werror=array-bounds]
20 | initialVelocities.back() = 6;
| ~~^~
cc1plus: some warnings being treated as errors
Compiler returned: 1
```
https://gcc.godbolt.org/z/sYrK6o54a
[Bug tree-optimization/108499] False positive -Warray-bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108499 --- Comment #2 from Stephen --- > There is no way to figure out for the compiler that theSize is not zero > either. There is no way for the compiler to figure out that theSize *is* zero. We have warnings -Wmaybe-uninitialized and -Wuninitialized. This warning is -Warray-bounds, not -Wmaybe-array-bounds. This warning should not be emitted.
[Bug tree-optimization/108499] False positive -Warray-bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108499 --- Comment #3 from Stephen --- False positives with this will just lead to proliferation of -Wno-array-bounds, which doesn't help.
[Bug c++/108197] New: -Wstringop-overread emitted on simple boost small_vector code
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108197
Bug ID: 108197
Summary: -Wstringop-overread emitted on simple boost
small_vector code
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
```
#include
struct MyThing
{
int d0 = {};
};
void modify(boost::container::small_vector &pp)
{
pp.resize(1);
pp[0].d0 = 3;
}
void foo()
{
boost::container::small_vector pp2;
boost::container::small_vector pp;
pp.resize(1);
pp[0].d0 = 2;
pp2 = std::move(pp);
}
```
gives
```
/opt/compiler-explorer/libs/boost_1_80_0/boost/container/detail/copy_move_algo.hpp:184:19:
warning: 'void* __builtin_memcpy(void*, const void*, long unsigned int)'
reading between 41 and 9223372036854775804 bytes from a region of size 40
[-Wstringop-overread]
184 | std::memmove(dest_raw, beg_raw, sizeof(value_type)*n);
```
https://godbolt.org/z/rs3oj3YoE
Even though modify is never called, it must be in the code to reproduce the
bug.
[Bug tree-optimization/108197] [12/13 Regression] -Wstringop-overread emitted on simple boost small_vector code
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108197 --- Comment #2 from Stephen --- Richard, are you saying this a bug in the boost code? It's not quite clear to me from your message. Can you be more specific about what the bug is in that case?
[Bug c++/105968] New: GCC vectorizes but reports that it did not vectorize
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105968
Bug ID: 105968
Summary: GCC vectorizes but reports that it did not vectorize
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: steveire at gmail dot com
Target Milestone: ---
I'm looking for a way to know if GCC autovectorizes some code.
Starting with this testcase which I picked up somewhere:
```
#define N 1
#define NTIMES 10
double a[N] __attribute__ ((aligned (16)));
double b[N] __attribute__ ((aligned (16)));
double c[N] __attribute__ ((aligned (16)));
double r[N] __attribute__ ((aligned (16)));
int muladd (void) {
int i, times;
for (times = 0; times < NTIMES; times++) {
#if 1
// count up
for (i = 0; i < N; ++i)
r[i] = (a[i] + b[i]) * c[i];
#else
// count down (old gcc won't auto-vectorize)
for (i = N-1; i >= 0; --i)
r[i] = (a[i] + b[i]) * c[i];
#endif
}
return 0;
}
```
the command
```
g++ -O2 -ftree-vectorize -fno-verbose-asm -mavx2 -fopt-info-vec-all -c test.cpp
```
reports
```
test.cpp:9:5: note: vectorized 1 loops in function.
```
However, with -O3, GCC reports that it did not vectorize:
```
g++ -O3 -ftree-vectorize -fno-verbose-asm -mavx2 -fopt-info-vec-all -c test.cpp
```
output:
```
test.cpp:9:5: note: vectorized 0 loops in function.
```
even though vector instructions are generated.
Demo https://godbolt.org/z/3o41r7jWc
[Bug c++/96117] Cannot mix c++11-style and GCC-style attributes on struct in one specific location
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96117 Stephen changed: What|Removed |Added Resolution|--- |FIXED Status|NEW |RESOLVED --- Comment #3 from Stephen --- This seems to be fixed in the latest release https://godbolt.org/z/Kdsrs76PT https://developers.redhat.com/articles/2023/06/21/new-c-features-gcc-13#additional_updates
