[Bug c++/83046] New: ICE in nvptx offloading, C++ compilation of libgomp.oacc-c-c++-common/gang-static-2.c

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83046

            Bug ID: 83046
           Summary: ICE in nvptx offloading, C++ compilation of
                    libgomp.oacc-c-c++-common/gang-static-2.c
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Keywords: openacc
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

... starting with r254437 "Instrument function exit with __builtin_unreachable
in C++".

    Program received signal SIGSEGV, Segmentation fault.
    input_offload_tables (do_force_output=true) at
[...]/source-gcc/gcc/lto-cgraph.c:1942
    1942                    varpool_node::get (var_decl)->force_output = 1;
    (gdb) bt
    #0  input_offload_tables (do_force_output=true) at
[...]/source-gcc/gcc/lto-cgraph.c:1942
    #1  0x00000000005a0927 in read_cgraph_and_symbols (fnames=<optimized out>,
nfiles=<optimized out>) at [...]/source-gcc/gcc/lto/lto.c:2863
    #2  lto_main () at [...]/source-gcc/gcc/lto/lto.c:3314
    #3  0x0000000000a7f63f in compile_file () at
[...]/source-gcc/gcc/toplev.c:455
    #4  0x000000000056ef20 in do_compile () at
[...]/source-gcc/gcc/toplev.c:2059
    #5  toplev::main (this=this@entry=0x7fffffffcfb0, argc=argc@entry=15,
argv=0x17908e0, argv@entry=0x7fffffffd0b8) at
[...]/source-gcc/gcc/toplev.c:2194
    #6  0x0000000000571457 in main (argc=15, argv=0x7fffffffd0b8) at
[...]/source-gcc/gcc/main.c:39

Obviously, that test case has a "-Wreturn-type mismatch" (which is not
diagnosed for C++; see reduced PR83045), and fixing that cures this nvptx
offloading ICE.