[Bug c/99736] New: Statement expression (gcc extension) cannot return struct with variable length array

[Bug c/99736] New: Statement expression (gcc extension) cannot return struct with variable length array

[tunagul29 at icloud dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99736

            Bug ID: 99736
           Summary: Statement expression (gcc extension) cannot return
                    struct with variable length array
           Product: gcc
           Version: 9.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tunagul29 at icloud dot com
  Target Milestone: ---

Created attachment 50463
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50463&action=edit
C file which contains the bug

Statement Expressions cannot return an anonymous struct with variable length
array object. I attached the file but here is the bug:

"""
int main() {
        ({
                unsigned int length = 10;
                struct {
                        int array[length];
                } new_object;
                new_object;
        });
}
"""

I conpiled it with mingcw and gcc 9.3 on wsl, both failed.

I am using gcc 9.3.0 wich gives the output: 
"""
test2.c: In function ‘main’:
test2.c:7:3: internal compiler error: in gimplify_var_or_parm_decl, at
gimplify.c:2755
    7 |  ({
      |  ~^
    8 |   unsigned int length = foo();
      |   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    9 |   struct {
      |   ~~~~~~~~
   10 |    int array[length];
      |    ~~~~~~~~~~~~~~~~~~
   11 |   } new_object;
      |   ~~~~~~~~~~~~~
   12 |   new_object;
      |   ~~~~~~~~~~~
   13 |  });
      |  ~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-9/README.Bugs> for instructions.
"""
with -Wall and -Wextra flags.

gcc -v output:

"""
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
9.3.0-17ubuntu1~20.04' --with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-9
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-gnu-unique-object --disable-vtable-verify --enable-plugin
--enable-default-pie --with-system-zlib --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib
--with-tune=generic
--enable-offload-targets=nvptx-none=/build/gcc-9-HskZEa/gcc-9-9.3.0/debian/tmp-nvptx/usr,hsa
--without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)
"""

[Bug c/99736] Statement expression (gcc extension) cannot return struct (with variable length array) object

[tunagul29 at icloud dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99736

--- Comment #1 from Tuna Gül <tunagul29 at icloud dot com> ---
Sorry for wrong compiler output
This should be the compiler output
(I dont know how to edit the original description)
"""
test.c: In function ‘main’:
test.c:2:3: internal compiler error: in gimplify_var_or_parm_decl, at
gimplify.c:2755
    2 |  ({
      |  ~^
    3 |   unsigned int length = 10;
      |   ~~~~~~~~~~~~~~~~~~~~~~~~~
    4 |   struct {
      |   ~~~~~~~~
    5 |    int array[length];
      |    ~~~~~~~~~~~~~~~~~~
    6 |   } new_object;
      |   ~~~~~~~~~~~~~
    7 |   new_object;
      |   ~~~~~~~~~~~
    8 |  });
      |  ~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-9/README.Bugs> for instructions.
"""

[Bug middle-end/99736] Statement expression (gcc extension) cannot return struct with variable length array

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99736

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |DUPLICATE
            Summary|Statement expression (gcc   |Statement expression (gcc
                   |extension) cannot return    |extension) cannot return
                   |struct (with variable       |struct with variable length
                   |length array) object        |array
           Keywords|                            |ice-on-valid-code
          Component|c                           |middle-end

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Dup of bug 29970.

*** This bug has been marked as a duplicate of bug 29970 ***