[Bug c++/70449] New: ICE with -Wall on valid code on x86_64-linux-gnu in pp_string, at pretty-print.c:928

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70449

            Bug ID: 70449
           Summary: ICE with -Wall on valid code on x86_64-linux-gnu in
                    pp_string, at pretty-print.c:928
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

The following code causes an ICE when compiled with the current GCC trunk with
-Wall on x86_64-linux-gnu in both 32-bit and 64-bit modes.  

This is a regression from 5.3.x.


$ g++-trunk -v
Using built-in specs.
COLLECT_GCC=g++-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/usr/local/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 6.0.0 20160329 (experimental) [trunk revision 234516] (GCC) 
$ 
$ g++-trunk -c small.cpp
$ g++-5.3 -c -Wall -std=c++14 small.cpp
: In instantiation of ‘constexpr int f() [with int I = 0]’:
small.cpp:4:22:   required from here
cc1plus: warning: no return statement in function returning non-void
[-Wreturn-type]
$ 
$ g++-trunk -c -Wall small.cpp

in pp_string, at pretty-print.c:928
0x15173f6 pp_string(pretty_printer*, char const*)
        ../../gcc-source-trunk/gcc/pretty-print.c:928
0x1517d22 pp_format(pretty_printer*, text_info*)
        ../../gcc-source-trunk/gcc/pretty-print.c:570
0x1518870 pp_format_verbatim(pretty_printer*, text_info*)
        ../../gcc-source-trunk/gcc/pretty-print.c:692
0x1518944 pp_verbatim(pretty_printer*, char const*, ...)
        ../../gcc-source-trunk/gcc/pretty-print.c:893
0x70cd08 print_instantiation_full_context
        ../../gcc-source-trunk/gcc/cp/error.c:3320
0x70cd08 maybe_print_instantiation_context
        ../../gcc-source-trunk/gcc/cp/error.c:3463
0x71734f cp_diagnostic_starter
        ../../gcc-source-trunk/gcc/cp/error.c:3156
0x151344c diagnostic_report_diagnostic(diagnostic_context*, diagnostic_info*)
        ../../gcc-source-trunk/gcc/diagnostic.c:826
0x1513b44 warning(int, char const*, ...)
        ../../gcc-source-trunk/gcc/diagnostic.c:1006
0x657e2e finish_function(int)
        ../../gcc-source-trunk/gcc/cp/decl.c:14755
0x67b6b2 instantiate_decl(tree_node*, int, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:22035
0x84bd62 cxx_eval_call_expression
        ../../gcc-source-trunk/gcc/cp/constexpr.c:1297
0x84dadf cxx_eval_constant_expression
        ../../gcc-source-trunk/gcc/cp/constexpr.c:3423
0x853c19 cxx_eval_outermost_constant_expr
        ../../gcc-source-trunk/gcc/cp/constexpr.c:3988
0x856bb5 fold_non_dependent_expr(tree_node*)
        ../../gcc-source-trunk/gcc/cp/constexpr.c:4251
0x649d97 build_enumerator(tree_node*, tree_node*, tree_node*, tree_node*,
unsigned int)
        ../../gcc-source-trunk/gcc/cp/decl.c:13484
0x746062 cp_parser_enumerator_definition
        ../../gcc-source-trunk/gcc/cp/parser.c:17414
0x746062 cp_parser_enumerator_list
        ../../gcc-source-trunk/gcc/cp/parser.c:17343
0x746062 cp_parser_enum_specifier
        ../../gcc-source-trunk/gcc/cp/parser.c:17270
0x72f4b9 cp_parser_type_specifier
        ../../gcc-source-trunk/gcc/cp/parser.c:15806
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ 


---------------------------


template <int I> 
constexpr int f ()
{
  enum E { a = f<0> () };
  return 0; 
}