[Bug tree-optimization/104679] New: [12 Regression] ICE in connect_traces, at dwarf2cfi.c:3071 since r12-6637-g463d9108766dcbb6

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104679

            Bug ID: 104679
           Summary: [12 Regression] ICE in connect_traces, at
                    dwarf2cfi.c:3071 since r12-6637-g463d9108766dcbb6
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: jakub at redhat dot com
  Target Milestone: ---

Reduced from libreoffice:

$ cat ice.ii
namespace rtl {
struct OStringBuffer {
  ~OStringBuffer();
};
} // namespace rtl
using rtl::OStringBuffer;
void lclSplitBlock(double, long);
void lclAppendBlock();
double ScInterpreterScBahtText_fBaht;
long ScInterpreterScBahtText_nSatang;
void ScInterpreterScBahtText() {
  lclSplitBlock(ScInterpreterScBahtText_fBaht,
ScInterpreterScBahtText_nSatang);
  if (ScInterpreterScBahtText_fBaht == 0.0)
    ;
  else
    while (ScInterpreterScBahtText_fBaht > 0.0) {
      OStringBuffer aBlock;
      lclAppendBlock();
    }
}

$ g++ ice.ii -O2 -m32 -c
during RTL pass: dwarf2
ice.ii: In function ‘void ScInterpreterScBahtText()’:
ice.ii:20:1: internal compiler error: in connect_traces, at dwarf2cfi.cc:3071
   20 | }
      | ^
0x7d36b1 connect_traces
        /home/marxin/Programming/gcc/gcc/dwarf2cfi.cc:3071
0x7d36b1 execute_dwarf2_frame
        /home/marxin/Programming/gcc/gcc/dwarf2cfi.cc:3302
0x7d36b1 execute
        /home/marxin/Programming/gcc/gcc/dwarf2cfi.cc:3789
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.