[Bug tree-optimization/61385] New: ICE on valid code at -O2 and -O3 on x86_64-linux-gnu

[Bug tree-optimization/61385] New: ICE on valid code at -O2 and -O3 on x86_64-linux-gnu

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61385

            Bug ID: 61385
           Summary: ICE on valid code at -O2 and -O3 on x86_64-linux-gnu
           Product: gcc
           Version: unknown
            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
-O2 and -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 20140601 (experimental) [trunk revision 211115] (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 ‘fn1’:
small.c:6:1: internal compiler error: Segmentation fault
 fn1 ()
 ^
0x98642f crash_signal
    ../../gcc-trunk/gcc/toplev.c:337
0x7a0c09 is_gimple_val(tree_node*)
    ../../gcc-trunk/gcc/gimple-expr.c:814
0x9aa66d verify_gimple_assign_binary
    ../../gcc-trunk/gcc/tree-cfg.c:3582
0x9b5aff verify_gimple_in_cfg(function*, bool)
    ../../gcc-trunk/gcc/tree-cfg.c:4889
0x8cdc5e execute_function_todo
    ../../gcc-trunk/gcc/passes.c:1777
0x8ce4a3 execute_todo
    ../../gcc-trunk/gcc/passes.c:1834
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, b, c, d, e, f, g;

int
fn1 ()
{
  int *h = &c;
  for (; c < 1; c++)
    {
      int *i = &a, *k = &a;
      f = 0;
      if (b)
    return 0;
      if (*h)
    {
      int **j = &i;
      *j = 0;
      d = 0;
    }
      else
    g = e = 0;
      if (*h)
    {
      int **l = &k;
      *l = &g;
    }
      d &= *h;
      assert (k == &a || k);
      assert (i);
    }
  return 0;
}

int
main ()
{
  fn1 (); 
  return 0;
}
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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/61378] Obvious bug in vn_reference_lookup_3
Date: Mon, 02 Jun 2014 07:45:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ida378

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Mon Jun  2 07:45:15 2014
New Revision: 211126

URL: http://gcc.gnu.org/viewcvs?rev!1126&root=gcc&view=rev
Log:
2014-06-02  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/61378
    * tree-ssa-sccvn.c (vn_reference_lookup_3): Initialize
    valueized_anything.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-sccvn.c

[Bug tree-optimization/61385] [4.10 Regression] ICE on valid code at -O2 and -O3 on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61385

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-06-02
                 CC|                            |glisse at gcc dot gnu.org
            Version|unknown                     |4.10.0
   Target Milestone|---                         |4.10.0
            Summary|ICE on valid code at -O2    |[4.10 Regression] ICE on
                   |and -O3 on x86_64-linux-gnu |valid code at -O2 and -O3
                   |                            |on x86_64-linux-gnu
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
phiopt leaves a STMT around that references a released SSA name.

Confirmed.  Suspect CCed.

[Bug tree-optimization/61385] [4.10 Regression] ICE on valid code at -O2 and -O3 on x86_64-linux-gnu

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61385

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r210212.

[Bug tree-optimization/61385] [4.10 Regression] ICE on valid code at -O2 and -O3 on x86_64-linux-gnu

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61385

--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> ---
Ah, right, I use last_and_only_stmt (middle_bb) but that doesn't prove there
are no PHI nodes there. Easiest fix, something like:

if (!gimple_seq_empty_p (phi_nodes (middle_bb)))
  return 0;

A better fix would be to move the PHI nodes from middle_bb to the same block as
we are moving the assignment. I am just not completely sure how safe that is
(or how to do that, but I'll probably find examples nearby).