[Bug rtl-optimization/64087] New: ICE on valid code at -O3 on x86_64-linux-gnu in in lra_create_live_ranges, at lra-lives.c:1330

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64087

            Bug ID: 64087
           Summary: ICE on valid code at -O3 on x86_64-linux-gnu in in
                    lra_create_live_ranges, at lra-lives.c:1330
           Product: gcc
           Version: 5.0
            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
-O3 on x86_64-linux-gnu in 64-bit mode (but not 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/5.0.0/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 5.0.0 20141126 (experimental) [trunk revision 218072] (GCC) 

$    
$ gcc-trunk -m64 -O2 small.c; a.out
$ gcc-trunk -m32 -O3 small.c; a.out
$ gcc-4.9 -m64 -O3 small.c; a.out
$ 
$ gcc-trunk -m64 -O3 small.c
small.c: In function ‘main’:
small.c:31:1: internal compiler error: in lra_create_live_ranges, at
lra-lives.c:1330
 }
 ^
0x943b37 lra_create_live_ranges(bool, bool)
    ../../gcc-trunk/gcc/lra-lives.c:1330
0x92af7c lra(_IO_FILE*)
    ../../gcc-trunk/gcc/lra.c:2299
0x8e96e9 do_reload
    ../../gcc-trunk/gcc/ira.c:5391
0x8e96e9 execute
    ../../gcc-trunk/gcc/ira.c:5561
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 printf (const char *, ...);

int a[72], b, c, d, e;

int
main ()
{
  int h;
  for (b = 0; b < 72; b++)
    {
      h = 1;
      if (b)
    h >>= 1;
      a[b] = h;
    }
  for (; e; e++)
    for (c = 0; c < 1;)
      for (; d;)
    {
      printf ("0");
      int g;
      for (b = 0; b < 72; b++)
        {
          g = 1;
          if (b)
        g >>= 1;
          a[b] = g;
        }
    }
  return 0;
}