[Bug tree-optimization/55008] New: Internal compiler error : verify_ssa failed

[Bug tree-optimization/55008] New: Internal compiler error : verify_ssa failed

[merkil at savhon dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55008

             Bug #: 55008
           Summary: Internal compiler error : verify_ssa failed
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: merkil@savhon.org


Hello !
The following testcase makes GCC 4.8.0 20121021 crash on my x86_64 machine (at
-O2 and higher) :

$ cat verify_ssa.c
#include <stdint.h>

void f(void)
{
    int a, *p;

    uint64_t b = 6309343725;

    if(*p ? (b = 1) : 0)
        if(b - (a = b /= 0) ? : (a + b))
            while(1);
}

$ xgcc -w -O2 verify_ssa.c
verify_ssa.c: In function ‘f’:
verify_ssa.c:3:6: error: definition in block 3 follows the use
 void f(void)
      ^
for SSA_NAME: _12 in statement:
_12 = _12;
verify_ssa.c:3:6: internal compiler error: verify_ssa failed
linux-vdso.so.1: No such file or directory
0xa2cc93 verify_ssa(bool)
    ../../srcdir/gcc/tree-ssa.c:1052
0x82f7a2 execute_function_todo
    ../../srcdir/gcc/passes.c:1957
0x8304cd execute_todo
    ../../srcdir/gcc/passes.c:1989
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.

[Bug tree-optimization/55008] Internal compiler error : verify_ssa failed

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55008

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-10-21
                 CC|                            |mpolacek at gcc dot
                   |                            |gnu.org, wschmidt at gcc
                   |                            |dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-10-21 20:00:32 UTC ---
Started with http://gcc.gnu.org/viewcvs?view=revision&revision=190220

[Bug tree-optimization/55008] [4.8 Regression] Internal compiler error : verify_ssa failed

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55008

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.8.0
            Summary|Internal compiler error :   |[4.8 Regression] Internal
                   |verify_ssa failed           |compiler error : verify_ssa
                   |                            |failed

[Bug tree-optimization/55008] [4.8 Regression] Internal compiler error : verify_ssa failed

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55008

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> 2012-10-22 09:55:21 UTC ---
The typedef there is essential, without stdint.h can be reproduced e.g. on
typedef unsigned long int T;

void
foo (int a, int *p)
{
  T b = 6309343725;
  if (*p ? (b = 1) : 0)
    if (b - (a = b /= 0) ? : (a + b))
      while (1)
        ;
}

but not when b is unsigned long long int directly.  slsr decides to change _12
= _9 + b_7; stmt to _12 = _12;, which is of course wrong.

[Bug tree-optimization/55008] [4.8 Regression] Internal compiler error : verify_ssa failed

[wschmidt at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55008

William J. Schmidt <wschmidt at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |wschmidt at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #3 from William J. Schmidt <wschmidt at gcc dot gnu.org> 2012-10-22 13:48:26 UTC ---
Mine.  Just unburying myself after vacation, but will take a look as soon as I
can.

[Bug tree-optimization/55008] [4.8 Regression] Internal compiler error : verify_ssa failed

[wschmidt at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55008

--- Comment #4 from William J. Schmidt <wschmidt at gcc dot gnu.org> 2012-10-22 15:41:41 UTC ---
Simple enough.  The statement has two interpretations and one looks like a
basis for the other.  Surprised this never came up before.  Adding a check to
avoid letting a statement treat itself as a basis should take care of this.

[Bug tree-optimization/55008] [4.8 Regression] Internal compiler error : verify_ssa failed

[wschmidt at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55008

--- Comment #5 from William J. Schmidt <wschmidt at gcc dot gnu.org> 2012-10-22 22:09:29 UTC ---
Author: wschmidt
Date: Mon Oct 22 22:09:22 2012
New Revision: 192696

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192696
Log:
gcc:

2012-10-22  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

    PR tree-optimization/55008
    * gimple-ssa-strength-reduction.c (find_basis_for_candidate): Don't
    allow a candidate to be a basis for itself under another interpretation.

gcc/testsuite:

2012-10-22  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

    PR tree-optimization/55008
    * gcc.dg/tree-ssa/pr55008.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr55008.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-ssa-strength-reduction.c
    trunk/gcc/testsuite/ChangeLog

[Bug tree-optimization/55008] [4.8 Regression] Internal compiler error : verify_ssa failed

[wschmidt at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55008

William J. Schmidt <wschmidt at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #6 from William J. Schmidt <wschmidt at gcc dot gnu.org> 2012-10-22 22:19:06 UTC ---
Fixed.