[Bug rtl-optimization/61220] New: ICE on valid code at -O2 on x86_64-linux-gnu in maybe_record_trace_start, at dwarf2cfi.c:2239

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61220

            Bug ID: 61220
           Summary: ICE on valid code at -O2 on x86_64-linux-gnu in
                    maybe_record_trace_start, at dwarf2cfi.c:2239
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu

The following code causes an ICE when compiled with the current gcc trunk at
-O2 on x86_64-linux-gnu in 64-bit mode (but not in 32-bit mode). 

It is a regression from 4.9.x.

$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/4.10.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 4.10.0 20140518 (experimental) [trunk revision 210581] (GCC) 
$ 
$ gcc-trunk -Os small.c; a.out
$ gcc-4.9.0 -O2 small.c; a.out
$ 
$ gcc-trunk -O2 small.c
small.c: In function ‘main’:
small.c:36:1: internal compiler error: in maybe_record_trace_start, at
dwarf2cfi.c:2239
 }
 ^
0x68d049 maybe_record_trace_start
    ../../gcc-trunk/gcc/dwarf2cfi.c:2239
0x68d7b6 scan_trace
    ../../gcc-trunk/gcc/dwarf2cfi.c:2416
0x68df5a create_cfi_notes
    ../../gcc-trunk/gcc/dwarf2cfi.c:2570
0x68df5a execute_dwarf2_frame
    ../../gcc-trunk/gcc/dwarf2cfi.c:2925
0x68df5a execute
    ../../gcc-trunk/gcc/dwarf2cfi.c:3405
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.
$  

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

int a, c, d, e, f, g, h, i, j, k;

struct S0
{
  int f0;
  int f1;
  int f2;
};

struct S1
{
  int f0;
  int f1;
  struct S0 f2;
} b; 

void
fn1 (struct S1 p)
{
  for (; k; k++)
    h = j ? a : a - 1;
  d &= i;
}

int
main ()
{
  int l[5] = { 0 };
  fn1 (b);
  for (c = 0; c < 3; c++)
    for (g = 0; g < 3; g++)
      l[c * 2] = e = l[c];
  if (f)
    fn1 (b);
  return 0;
}