[Bug c++/57178] bogus warning with -O3 using boost::optional

[Bug c++/57178] bogus warning with -O3 using boost::optional

[eda-qa at disemia dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57178

--- Comment #1 from eda-qa at disemia dot com 2013-05-05 14:56:35 UTC ---
Created attachment 30034
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30034
example

[Bug c++/57178] New: bogus warning with -O3 using boost::optional

[eda-qa at disemia dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57178

             Bug #: 57178
           Summary: bogus warning with -O3 using boost::optional
    Classification: Unclassified
           Product: gcc
           Version: 4.6.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: eda-qa@disemia.com


GCC appears to be producing a bogus warning about an unitialized value. This
happens at optimization levels -O1 and higher. It uses a boost optional as I
was unable to reduce it to something more fundamental.

Command line:

g++ -c uninit_warn.cpp --std=c++0x -Wuninitialized -O1

Warning:
uninit_warn.cpp: In function ‘void test(boost::optional<int>)’:
uninit_warn.cpp:17:12: warning: ‘*((void*)& q +4)’ may be used uninitialised in
this function [-Wuninitialized]
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From: "cartonmartin+gcc_bugzilla at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/57179] New: ICE on non-valid code with emplace_back
Date: Sun, 05 May 2013 15:19:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57179

             Bug #: 57179
           Summary: ICE on non-valid code with emplace_back
    Classification: Unclassified
           Product: gcc
           Version: 4.7.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: cartonmartin+gcc_bugzilla@gmail.com


Created attachment 30035
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30035
Preprocessed file g++ is asking me to give

The following code produces an internal compiler error.
The code is so simple that I am surprised I did not find a bug report for it.

====== Code ======
#include <vector>

struct Sums {
    int pos;
};

int main() {
    std::vector<Sums> sums;
    sums.emplace_back(1);
}

====== g++ output ======
$ g++ -std=c++11 -v 345.cpp  
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.7.3-1ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.7 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.7 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin
--with-system-zlib --enable-objc-gc --with-cloog --enable-cloog-backend=ppl
--disable-cloog-version-check --disable-ppl-version-check --enable-multiarch
--disable-werror --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --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 4.7.3 (Ubuntu/Linaro 4.7.3-1ubuntu1) 
COLLECT_GCC_OPTIONS='-std=c++11' '-v' '-shared-libgcc' '-mtune=generic'
'-march=x86-64'
 /usr/lib/gcc/x86_64-linux-gnu/4.7/cc1plus -quiet -v -imultilib . -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE 345.cpp -quiet -dumpbase 345.cpp -mtune=generic
-march=x86-64 -auxbase 345 -std=c++11 -version -fstack-protector -o
/tmp/ccBHCW6S.s
GNU C++ (Ubuntu/Linaro 4.7.3-1ubuntu1) version 4.7.3 (x86_64-linux-gnu)
    compiled by GNU C version 4.7.3, GMP version 5.0.5, MPFR version 3.1.1-p2,
MPC version 0.9
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/4.7"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/include/c++/4.7
 /usr/include/x86_64-linux-gnu/c++/4.7/.
 /usr/include/c++/4.7/backward
 /usr/lib/gcc/x86_64-linux-gnu/4.7/include
 /usr/local/include
 /usr/lib/gcc/x86_64-linux-gnu/4.7/include-fixed
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
GNU C++ (Ubuntu/Linaro 4.7.3-1ubuntu1) version 4.7.3 (x86_64-linux-gnu)
    compiled by GNU C version 4.7.3, GMP version 5.0.5, MPFR version 3.1.1-p2,
MPC version 0.9
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 7c3b96402a8920876e03e4e0d436665c
‘
Internal compiler error: Error reporting routines re-entered.
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-4.7/README.Bugs> for instructions.
Preprocessed source stored into /tmp/cca4SK6X.out file, please attach this to
your bugreport.
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Subject: [Bug libstdc++/57173] Regex match group contain extraneous character...
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idW173

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-05-05 15:49:54 UTC ---
std::regex is unimplemented, it's not expected to work.

*** This bug has been marked as a duplicate of bug 53631 ***

[Bug c++/57178] bogus warning with -O3 using boost::optional

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57178

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
      Known to work|                            |4.8.0, 4.9.0
         Resolution|                            |FIXED

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-05-05 23:25:44 UTC ---
This is fixed in 4.8.0.