[Bug c++/108099] New: ICE when parsing signed __int128_t typedef

["moritz.klammler at cetitec dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108099

            Bug ID: 108099
           Summary: ICE when parsing signed __int128_t typedef
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: moritz.klammler at cetitec dot com
  Target Milestone: ---

There seems to be a problem in the parser regarding typedefs involving
__int128_t prefixed with the signed keyword.

$ cat test.ii
using i128 = signed __int128_t;

$ g++ -v -c test.ii
Using built-in specs.
COLLECT_GCC=g++
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --enable-bootstrap
--prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/
--with-build-config=bootstrap-lto --with-linker-hash-style=gnu
--with-system-zlib --enable-__cxa_atexit --enable-cet=auto
--enable-checking=release --enable-clocale=gnu --enable-default-pie
--enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object
--enable-libstdcxx-backtrace --enable-link-serialization=1
--enable-linker-build-id --enable-lto --enable-multilib --enable-plugin
--enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch
--disable-werror
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.2.0 (GCC) 
COLLECT_GCC_OPTIONS='-v' '-c' '-shared-libgcc' '-mtune=generic' '-march=x86-64'
 /usr/lib/gcc/x86_64-pc-linux-gnu/12.2.0/cc1plus -fpreprocessed test.ii -quiet
-dumpbase test.ii -dumpbase-ext .ii -mtune=generic -march=x86-64 -version -o
/tmp/ccn4pU5h.s
GNU C++17 (GCC) version 12.2.0 (x86_64-pc-linux-gnu)
        compiled by GNU C version 12.2.0, GMP version 6.2.1, MPFR version
4.1.0-p13, MPC version 1.2.1, isl version isl-0.25-GMP

warning: MPFR header version 4.1.0-p13 differs from library version 4.1.1-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++17 (GCC) version 12.2.0 (x86_64-pc-linux-gnu)
        compiled by GNU C version 12.2.0, GMP version 6.2.1, MPFR version
4.1.0-p13, MPC version 1.2.1, isl version isl-0.25-GMP

warning: MPFR header version 4.1.0-p13 differs from library version 4.1.1-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 402ce889a414e2a3abbbe3146fa0a6cb
test.ii:1:21: internal compiler error: Segmentation fault
    1 | using i128 = signed __int128_t;
      |                     ^~~~~~~~~~
0x19eab38 internal_error(char const*, ...)
        ???:0
0x6f5f81 grokdeclarator(cp_declarator const*, cp_decl_specifier_seq*,
decl_context, int, tree_node**)
        ???:0
0x6fc532 groktypename(cp_decl_specifier_seq*, cp_declarator const*, bool)
        ???:0
0x7c7a9c c_parse_file()
        ???:0
0x8dcedd c_common_parse_file()
        ???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://bugs.archlinux.org/> for instructions.

Interestingly, std::make_signed_t<__int128_t> is compiled fine.

I have also tried a few variations in C and while a similar issue seems to
exist, no segfault happened.

$ cat test.i
typedef unsigned __int128_t number;
typedef   signed __int128_t number;

$ gcc -v -c test.i
Using built-in specs.
COLLECT_GCC=gcc
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --enable-bootstrap
--prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/
--with-build-config=bootstrap-lto --with-linker-hash-style=gnu
--with-system-zlib --enable-__cxa_atexit --enable-cet=auto
--enable-checking=release --enable-clocale=gnu --enable-default-pie
--enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object
--enable-libstdcxx-backtrace --enable-link-serialization=1
--enable-linker-build-id --enable-lto --enable-multilib --enable-plugin
--enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch
--disable-werror
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.2.0 (GCC) 
COLLECT_GCC_OPTIONS='-v' '-c' '-mtune=generic' '-march=x86-64'
 /usr/lib/gcc/x86_64-pc-linux-gnu/12.2.0/cc1 -fpreprocessed test.i -quiet
-dumpbase test.i -dumpbase-ext .i -mtune=generic -march=x86-64 -version -o
/tmp/ccdh1Nyr.s
GNU C17 (GCC) version 12.2.0 (x86_64-pc-linux-gnu)
        compiled by GNU C version 12.2.0, GMP version 6.2.1, MPFR version
4.1.0-p13, MPC version 1.2.1, isl version isl-0.25-GMP

warning: MPFR header version 4.1.0-p13 differs from library version 4.1.1-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C17 (GCC) version 12.2.0 (x86_64-pc-linux-gnu)
        compiled by GNU C version 12.2.0, GMP version 6.2.1, MPFR version
4.1.0-p13, MPC version 1.2.1, isl version isl-0.25-GMP

warning: MPFR header version 4.1.0-p13 differs from library version 4.1.1-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 4b798a352742e8322eaa4a166b8f6299
test.i:1:29: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before
‘number’
    1 | typedef unsigned __int128_t number;
      |                             ^~~~~~
test.i:2:29: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before
‘number’
    2 | typedef   signed __int128_t number;
      |                             ^~~~~~

I'm using GCC 12.2.0 as distributed with Archlinux on x86_64 GNU/Linux.