[Bug c/79494] New: ICE in maybe_record_trace_start, at dwarf2cfi.c:2330

["gerhard dot steinmetz dot fortran at t-online dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79494

            Bug ID: 79494
           Summary: ICE in maybe_record_trace_start, at dwarf2cfi.c:2330
           Product: gcc
           Version: 7.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gerhard.steinmetz.fortran@t-online.de
  Target Milestone: ---

Option -fsplit-stack gives this ICE for roughly two dozen files
from gcc/testsuite, for example (down to 4.9) :


$ cat pr49994-1.c
void x (int a)
{
  __label__ xlab;
  void y (int b)
  {
    switch (b)
      {
      case 1:
        goto xlab;
      case 2:
        goto xlab;
      }
  }
  y (a);
xlab:;
}


$ gcc-7-20170212 -fsplit-stack -c pr49994-1.c
pr49994-1.c: In function 'x':
pr49994-1.c:16:1: internal compiler error: in maybe_record_trace_start, at
dwarf2cfi.c:2330
 }
 ^
0x83e7eb maybe_record_trace_start
        ../../gcc/dwarf2cfi.c:2330
0x83eaf7 create_trace_edges
        ../../gcc/dwarf2cfi.c:2440
0x840cca scan_trace
        ../../gcc/dwarf2cfi.c:2640
0x84185a create_cfi_notes
        ../../gcc/dwarf2cfi.c:2666
0x84185a execute_dwarf2_frame
        ../../gcc/dwarf2cfi.c:3024
0x84185a execute
        ../../gcc/dwarf2cfi.c:3504