[Bug c/97882] New: Segmentation Fault on improper redeclaration of function

["jarod.keene at trojans dot dsu.edu" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97882

            Bug ID: 97882
           Summary: Segmentation Fault on improper redeclaration of
                    function
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jarod.keene at trojans dot dsu.edu
  Target Milestone: ---

Created attachment 49579
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49579&action=edit
Save Temps output from code compilation

After fuzzing GCC version 10.2.0 for grammar-based errors we discovered a
segmentation fault flaw within the compiler. This flaw is also none to be
present in GCC versions 7.5.0, 8.3.0, and 9.3.0. Attached is the output from
-save-temps.

GCC Compilation and system options:
Debian 5.8.0
Configured with: ../src/configure -v --with-pkgversion='Debian 10.2.0-16'
--with-bugurl=file:///usr/share/doc/gcc-10/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,m2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-10
--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 --enable-libphobos-checking=release
--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-10-YRn5ue/gcc-10-10.2.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-10-YRn5ue/gcc-10-10.2.0/debian/tmp-gcn/usr,hsa
--without-cuda-driver --enable-checking=yes,extra,rtl --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu

Compilation Command Line: gcc bug.c

Compilation Error Message:
bug.c: In function ‘x’:
bug.c:4:2: internal compiler error: Segmentation fault
    4 |  const unsigned x() {};
      |  ^~~~~
0xfe8a6f crash_signal
    ../../src/gcc/toplev.c:328
0x7f65d0b7ce2f ???
    ./signal/../sysdeps/unix/sysv/linux/x86_64/sigaction.c:0
0xb01de6 must_pass_in_stack_var_size_or_pad(function_arg_info const&)
    ../../src/gcc/calls.c:6216
0x130b3e8 ix86_must_pass_in_stack
    ../../src/gcc/config/i386/i386.c:1458
0x1337b4a classify_argument
    ../../src/gcc/config/i386/i386.c:2065
0x13383ca examine_argument
    ../../src/gcc/config/i386/i386.c:2459
0x1338d31 ix86_return_in_memory
    ../../src/gcc/config/i386/i386.c:3826
0xca98fe aggregate_value_p(tree_node const*, tree_node const*)
    ../../src/gcc/function.c:2111
0xcae74c allocate_struct_function(tree_node*, bool)
    ../../src/gcc/function.c:4814
0x9e9774 store_parm_decls()
    ../../src/gcc/c/c-decl.c:9781
0xa42092 c_parser_declaration_or_fndef
    ../../src/gcc/c/c-parser.c:2466
0xa21fff c_parser_compound_statement_nostart
    ../../src/gcc/c/c-parser.c:5718
0xa40764 c_parser_compound_statement
    ../../src/gcc/c/c-parser.c:5617
0xa42221 c_parser_declaration_or_fndef
    ../../src/gcc/c/c-parser.c:2505
0xa4a393 c_parser_external_declaration
    ../../src/gcc/c/c-parser.c:1745
0xa4ae91 c_parser_translation_unit
    ../../src/gcc/c/c-parser.c:1618
0xa4ae91 c_parse_file()
    ../../src/gcc/c/c-parser.c:21752
0xaa219b c_common_parse_file()
    ../../src/gcc/c-family/c-opts.c:1190