[Bug tree-optimization/57592] New: ICE in tree_unroll_loops_completely at -O3

[Bug tree-optimization/57592] New: ICE in tree_unroll_loops_completely at -O3

[dhazeghi at yahoo dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57592

            Bug ID: 57592
           Summary: ICE in tree_unroll_loops_completely at -O3
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dhazeghi at yahoo dot com

With current gcc trunk on x86_64-linux, the following code causes an ICE when
compiled at -O3.  This is a regression from 4.8.x.

$ gcc-trunk -v
gcc version 4.9.0 20130611 (experimental) [trunk revision 199947] (GCC) 
$ gcc-trunk -m32 -O2 -c ice.c 
$ gcc-4.8 -m32 -O3 -c ice.c 
$ gcc-trunk -m32 -O3 -c ice.c 
ice.c: In function ‘f’:
ice.c:4:1: internal compiler error: Segmentation fault
 f ()
 ^
0x7d419f crash_signal
    ../../gcc-trunk/gcc/toplev.c:333
0x7fc29b ssa_default_def(function*, tree_node*)
    ../../gcc-trunk/gcc/tree-dfa.c:314
0x7fc560 get_or_create_ssa_default_def(function*, tree_node*)
    ../../gcc-trunk/gcc/tree-dfa.c:362
0x81585a get_reaching_def
    ../../gcc-trunk/gcc/tree-into-ssa.c:1184
0x81b9db maybe_replace_use
    ../../gcc-trunk/gcc/tree-into-ssa.c:1784
0x81b9db rewrite_update_stmt
    ../../gcc-trunk/gcc/tree-into-ssa.c:1967
0x81b9db rewrite_update_enter_block
    ../../gcc-trunk/gcc/tree-into-ssa.c:2136
0xb3561a walk_dominator_tree(dom_walk_data*, basic_block_def*)
    ../../gcc-trunk/gcc/domwalk.c:210
0x814563 rewrite_blocks
    ../../gcc-trunk/gcc/tree-into-ssa.c:2216
0x81ac8e update_ssa(unsigned int)
    ../../gcc-trunk/gcc/tree-into-ssa.c:3303
0xb99fe4 tree_unroll_loops_completely(bool, bool)
    ../../gcc-trunk/gcc/tree-ssa-loop-ivcanon.c:1207
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, b, c;

void
f ()
{
  int d, e;
  a = 0;
  for (; a <= 1; a++)
    {
      e = 4;
      for (; e; e--)
    {
      d |= c < b++;
      c = 0;
    }
    }
  g (d);
}
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From: "potswa at mac dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/57593] New: Friendship not extended into friend member-declaration
Date: Wed, 12 Jun 2013 06:19:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idW593

            Bug ID: 57593
           Summary: Friendship not extended into friend member-declaration
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: potswa at mac dot com

The access granted by friendship extends into the "member declarations of the
befriended class" (11.3/2). Friend declarations are member-declarations but not
member declarations per se, so the standard is ambiguous. But GCC is
inconsistent.

class c {
    class n {};
    friend struct s;
};

struct s {
    friend class c::n; // OK
    friend c::n g(); // OK
    friend void f() { c::n(); } // Error
};

All three should go the same way, if access is granted per declaration. If the
first two were invalid, private nested classes and related functions would be
impossible to befriend.

Rejection of the third case impedes use of a friend as part of a class
implementation, akin to members, such as the common case of operator <<. Clang
does accept it.

A defect report has been submitted.

[Bug tree-optimization/57592] [4.9 Regression] ICE in tree_unroll_loops_completely at -O3

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57592

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-06-12
                 CC|                            |eraman at gcc dot gnu.org,
                   |                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |4.9.0
            Summary|ICE in                      |[4.9 Regression] ICE in
                   |tree_unroll_loops_completel |tree_unroll_loops_completel
                   |y at -O3                    |y at -O3
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r199048.

[Bug tree-optimization/57592] [4.9 Regression] ICE in tree_unroll_loops_completely at -O3

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57592

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
t.c: In function 'f':
t.c:4:1: error: definition in block 3 follows the use
 f ()
 ^
for SSA_NAME: _27 in statement:
d_55 = _27 | _30;
t.c:4:1: internal compiler error: verify_ssa failed

after reassoc

*** This bug has been marked as a duplicate of bug 57393 ***