[Bug tree-optimization/61438] New: ICE on valid code at -O3 on x86_64-linux-gnu in in loop_preheader_edge, at cfgloop.c:1668

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61438

            Bug ID: 61438
           Summary: ICE on valid code at -O3 on x86_64-linux-gnu in in
                    loop_preheader_edge, at cfgloop.c:1668
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-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
-O3 on x86_64-linux-gnu in both 32-bit and 64-bit modes.

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 20140606 (experimental) [trunk revision 211322] (GCC) 
$ 
$ gcc-trunk -O2 small.c; a.out
$ gcc-4.9.0 -O3 small.c; a.out
$ 
$ gcc-trunk -O3 small.c
small.c: In function ‘foo’:
small.c:12:1: internal compiler error: in loop_preheader_edge, at
cfgloop.c:1668
 foo ()
 ^
0x62e9ce loop_preheader_edge(loop const*)
    ../../gcc-trunk/gcc/cfgloop.c:1668
0xa3a6e0 block_before_loop
    ../../gcc-trunk/gcc/tree-scalar-evolution.h:48
0xa3a6e0 analyze_scalar_evolution(loop*, tree_node*)
    ../../gcc-trunk/gcc/tree-scalar-evolution.c:2042
0xa3b9ea analyze_scalar_evolution_in_loop
    ../../gcc-trunk/gcc/tree-scalar-evolution.c:2139
0xa3bb4f simple_iv(loop*, loop*, tree_node*, affine_iv*, bool)
    ../../gcc-trunk/gcc/tree-scalar-evolution.c:3244
0xae08a9 eliminate_dom_walker::before_dom_children(basic_block_def*)
    ../../gcc-trunk/gcc/tree-ssa-pre.c:4217
0xe94927 dom_walker::walk(basic_block_def*)
    ../../gcc-trunk/gcc/domwalk.c:177
0xadd372 eliminate
    ../../gcc-trunk/gcc/tree-ssa-pre.c:4451
0xadd7c3 execute
    ../../gcc-trunk/gcc/tree-ssa-pre.c:4867
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.
$ 


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


#include <assert.h>

int a, c, **d, e, g;
static int b = 1;

struct
{
  int f0;
} f;

void
foo ()
{
  int h, *i = &a;
  for (; e;)
    {
      for (c = 0; c < 1; c++)
    for (; b;)
      ;
      for (;;)
    {
      if (a)
        {
          for (; f.f0; f.f0++)
        ;
          if (g)
        break;
        }
      for (h = 0; h < 2; h++)
        {
          i = *d;
          assert (i);
        }
    }
    }
  assert (i);
}

int
main ()
{
  foo (); 
  return 0;
}