[Bug tree-optimization/61197] New: wrong code at -O3 on x86_64-linux (in both 32-bit and 64-bit modes)

[Bug tree-optimization/61197] New: wrong code at -O3 on x86_64-linux (in both 32-bit and 64-bit modes)

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61197

            Bug ID: 61197
           Summary: wrong code at -O3 on x86_64-linux (in both 32-bit and
                    64-bit modes)
           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 current gcc trunk miscompiles the following code on x86_64-linux at -O3 in
both 32-bit and 64-bit modes.  

This is a regression from 4.9.x. 

It seems different from PR 61140 and PR 61150 as -fno-tree-dce makes both
disappear, but not this one. 

$ 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 20140515 (experimental) [trunk revision 210458] (GCC) 
$ 
$ gcc-trunk -O2 small.c; a.out
$ gcc-4.9.0 -O3 small.c; a.out
$ 
$ gcc-trunk -O3 small.c; a.out
Aborted (core dumped)
$


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


int a, b = 1, *c = &a; 

int
foo ()
{
  if (b)
    b |= 1;
  else
    {
      b = 1;
      return 0;
    }
  return 1;
}

int
main ()
{
  *c = foo ();
  if (a != 1) 
    __builtin_abort (); 
  return 0;
}

[Bug tree-optimization/61197] [4.10 Regression] wrong code at -O3 on x86_64-linux (in both 32-bit and 64-bit modes)

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61197

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-05-16
                 CC|                            |glisse at gcc dot gnu.org,
                   |                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |4.10.0
            Summary|wrong code at -O3 on        |[4.10 Regression] wrong
                   |x86_64-linux (in both       |code at -O3 on x86_64-linux
                   |32-bit and 64-bit modes)    |(in both 32-bit and 64-bit
                   |                            |modes)
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r210212.

[Bug tree-optimization/61197] [4.10 Regression] wrong code at -O3 on x86_64-linux (in both 32-bit and 64-bit modes)

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61197

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Zhendong Su from comment #0)
> It seems different from PR 61140 and PR 61150 as -fno-tree-dce makes both
> disappear, but not this one. 

Still the same bug (fixed by the same patch). I am sorry it is taking me so
long to commit it, it has been approved but I am traveling this week. Maybe
tomorrow.

[Bug tree-optimization/61197] [4.10 Regression] wrong code at -O3 on x86_64-linux (in both 32-bit and 64-bit modes)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61197

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Make sure to add all the various testcases.

[Bug tree-optimization/61197] [4.10 Regression] wrong code at -O3 on x86_64-linux (in both 32-bit and 64-bit modes)

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61197

--- Comment #4 from Marc Glisse <glisse at gcc dot gnu.org> ---
Author: glisse
Date: Sat May 17 12:37:58 2014
New Revision: 210554

URL: http://gcc.gnu.org/viewcvs?rev=210554&root=gcc&view=rev
Log:
2014-05-17  Marc Glisse  <marc.glisse@inria.fr>

    PR tree-optimization/61140
    PR tree-optimization/61150
    PR tree-optimization/61197
gcc/
    * tree-ssa-phiopt.c (value_replacement): Punt on multiple phis.
gcc/testsuite/
    * gcc.dg/tree-ssa/pr61140.c: New file.
    * gcc.dg/tree-ssa/pr61150.c: New file.
    * gcc.dg/tree-ssa/pr61197.c: New file.


Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr61140.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr61150.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr61197.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-phiopt.c

[Bug tree-optimization/61197] [4.10 Regression] wrong code at -O3 on x86_64-linux (in both 32-bit and 64-bit modes)

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61197

Marc Glisse <glisse at gcc dot gnu.org> changed:

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

--- Comment #5 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #3)
> Make sure to add all the various testcases.

Done.