[Bug c++/87437] New: g++ ICE Segfault initializing implicitly sized array in template with enum index

james at albanarts dot com gcc-bugzilla@gcc.gnu.org
Tue Sep 25 23:16:00 GMT 2018


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87437

            Bug ID: 87437
           Summary: g++ ICE Segfault initializing implicitly sized array
                    in template with enum index
           Product: gcc
           Version: 7.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: james at albanarts dot com
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu
             Build: x86_64-pc-linux-gnu

Created attachment 44751
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44751&action=edit
segfault.cpp - Really simple test case

I hit an internal compiler error in g++. Reduced test case attached and pasted
here:
enum E { ENUM };

template <typename T>
void foo()
{
        int arr[] = { [ENUM] = 0 };
}

Compiled like this on Gentoo (sys-devel/gcc-7.3.0-r3):

$ g++ -c -o segfault.o segfault.cpp 
segfault.cpp: In function ‘void foo()’:
segfault.cpp:6:27: internal compiler error: Segmentation fault
  int arr[] = { [ENUM] = 0 };
                           ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.gentoo.org/> for instructions.


It works if the template line is removed.
It works if ENUM is replaced with integer literal (i.e. "[0] = 0").
It works if an explicit size is given (i.e. "int arr[1]").


I'm not able to test on a newer version right now, but its a trivial test case,
maybe somebody else can check if its already fixed?

$ g++ -v
Using built-in specs.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/7.3.0/g++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/7.3.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-7.3.0-r3/work/gcc-7.3.0/configure
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/7.3.0
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.0/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/7.3.0
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/7.3.0/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/7.3.0/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/7.3.0/include/g++-v7
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/7.3.0/python
--enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt
--disable-werror --with-system-zlib --enable-nls --without-included-gettext
--enable-checking=release --with-bugurl=https://bugs.gentoo.org/
--with-pkgversion='Gentoo 7.3.0-r3 p1.4' --disable-esp --enable-libstdcxx-time
--enable-shared --enable-threads=posix --enable-__cxa_atexit
--enable-clocale=gnu --enable-multilib --with-multilib-list=m32,m64
--disable-altivec --disable-fixed-point --enable-targets=all --disable-libgcj
--enable-libgomp --disable-libmudflap --disable-libssp --disable-libcilkrts
--disable-libmpx --enable-vtable-verify --enable-libvtv --enable-lto
--without-isl --enable-libsanitizer --enable-default-pie --enable-default-ssp
Thread model: posix
gcc version 7.3.0 (Gentoo 7.3.0-r3 p1.4)


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