[Bug tree-optimization/59374] New: -ftree-slp-vectorize breaks unique_ptr's move constructor

[Bug tree-optimization/59374] New: -ftree-slp-vectorize breaks unique_ptr's move constructor

[niteria at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

            Bug ID: 59374
           Summary: -ftree-slp-vectorize breaks unique_ptr's move
                    constructor
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: niteria at gmail dot com

Created attachment 31358
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31358&action=edit
result of -save-temps

Test file (SmallCore.cpp):

#include <memory>
#include <iostream>

using namespace std;

class Foo {};
class Bar : public Foo {};

struct StlAllocator {
  StlAllocator() : alloc_(nullptr) {}
  explicit StlAllocator(void* p) : alloc_(p) {}
  void* alloc_;
};

struct BarDelete : public StlAllocator {
  void operator()(void*) const {}
};

struct FooDelete : public StlAllocator {
  FooDelete() = default;
  /* implicit */ FooDelete(const BarDelete& other) : StlAllocator(other.alloc_)
    {}
  void operator()(void*) const {}
};

unique_ptr<Bar, BarDelete> myalloc() {
  return unique_ptr<Bar, BarDelete>(new Bar);
}

void fun(const unique_ptr<Foo, FooDelete>& foo) {
  cout << "fun " << foo.get() << endl;
}

int main(int, char **) {
  std::unique_ptr<Foo, FooDelete> foo;
  std::unique_ptr<Bar, BarDelete> bar = myalloc();
  foo = std::move(bar);

  auto p = foo.get();
  cout << "p " << p << endl;
  if (p != foo.get()) {
    cout << "wtf" << endl;
    abort();
  }

  fun(foo);
  return 0;
}

Compiled with: g++ -std=c++11 -O -ftree-slp-vectorize SmallCore.cpp

Produces: 
$ ./a.out
p 0x602010
wtf
Aborted

Expected result (up to pointer address):
$ ./a.out
p 0x602010
fun 0x602010

Gcc versions:
Target: x86_64-unknown-linux-gnu
Configured with: ./configure --prefix=/data/users/bnitka/prefix/ --with-ppl
--with-cloog --enable-bootstrap --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-languages=c,c++
--disable-gnu-unique-object --enable-linker-build-id --with-gnu-as
--with-gnu-ld --disable-multilib --enable-libstdcxx-time
Thread model: posix
gcc version 4.8.1 (GCC)

Target: x86_64-unknown-linux-gnu
Configured with: ./configure --prefix=/data/users/bnitka/prefix/ --with-ppl
--with-cloog --enable-bootstrap --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-languages=c,c++
--disable-gnu-unique-object --enable-linker-build-id --with-gnu-as
--with-gnu-ld --disable-multilib --enable-libstdcxx-time
Thread model: posix
gcc version 4.9.0 20131202 (experimental) (GCC)

Works on:
gcc-4.7.1

[Bug tree-optimization/59374] [4.8/4.9 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |x86_64-*-*
             Status|UNCONFIRMED                 |ASSIGNED
      Known to work|                            |4.7.3
           Keywords|                            |wrong-code
   Last reconfirmed|                            |2013-12-03
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1
            Summary|-ftree-slp-vectorize breaks |[4.8/4.9 Regression]
                   |unique_ptr's move           |-ftree-slp-vectorize breaks
                   |constructor                 |unique_ptr's move
                   |                            |constructor
   Target Milestone|---                         |4.8.3
      Known to fail|                            |4.8.0, 4.8.2, 4.9.0

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  I will have a look.

[Bug tree-optimization/59374] [4.8/4.9 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
  bar = myalloc (); [return slot optimization]

  <bb 3>:
  _22 = MEM[(struct Bar * const &)&bar + 8];
  MEM[(struct Bar * &)&bar + 8] = 0B;
  MEM[(struct Foo * &)&foo + 8] = _22;
  _23 = MEM[(const struct BarDelete *)&bar].D.39226.alloc_;
  MEM[(struct deleter_type *)&foo] = _23;
  _7 = std::operator<< <std::char_traits<char> > (&cout, "p ");

is vectorized to

  bar = myalloc (); [return slot optimization]

  <bb 3>:
  _22 = MEM[(struct Bar * const &)&bar + 8];
  MEM[(struct Bar * &)&bar + 8] = 0B;
  vectp.87_1 = &MEM[(const struct BarDelete *)&bar].D.39226.alloc_;
  vect__23.88_36 = MEM[(const struct BarDelete *)vectp.87_1];
  _23 = MEM[(const struct BarDelete *)&bar].D.39226.alloc_;
  vectp.90_37 = &foo;
  MEM[(struct deleter_type *)vectp.90_37] = vect__23.88_36;
  _7 = std::operator<< <std::char_traits<char> > (&cout, "p ");

obvious violating a WAR dependency.  I'm sure it was me who broke this.

[Bug tree-optimization/59374] [4.8/4.9 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Testcase:


extern void abort (void);

static struct X { void *a; void *b; } a, b;

void __attribute__((noinline)) foo (void)
{
  void *tem = a.b;
  a.b = (void *)0;
  b.b = tem;
  b.a = a.a;
}

int main()
{
  a.b = &a;
  foo ();
  if (b.b != &a)
    abort ();
  return 0;
}

[Bug tree-optimization/59374] [4.8/4.9 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 31362
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31362&action=edit
patch

Patch I am testing.

[Bug tree-optimization/59374] [4.8/4.9 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Thu Dec  5 09:12:29 2013
New Revision: 205694

URL: http://gcc.gnu.org/viewcvs?rev=205694&root=gcc&view=rev
Log:
2013-12-05  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/59374
    * tree-vect-data-refs.c (vect_slp_analyze_data_ref_dependence):
    Commonize known and unknown dependence case fixing the allowed
    read-write dependence case and dropping code that should not
    matter.

    * gcc.dg/torture/pr59374-1.c: New testcase.
    * gcc.dg/torture/pr59374-2.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr59374-1.c
    trunk/gcc/testsuite/gcc.dg/torture/pr59374-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vect-data-refs.c

[Bug tree-optimization/59374] [4.8 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.9.0
            Summary|[4.8/4.9 Regression]        |[4.8 Regression]
                   |-ftree-slp-vectorize breaks |-ftree-slp-vectorize breaks
                   |unique_ptr's move           |unique_ptr's move
                   |constructor                 |constructor
      Known to fail|4.9.0                       |

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar.

[Bug tree-optimization/59374] [4.7/4.8/4.9 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|4.7.3, 4.9.0                |4.3.6, 4.4.7
            Summary|[4.8 Regression]            |[4.7/4.8/4.9 Regression]
                   |-ftree-slp-vectorize breaks |-ftree-slp-vectorize breaks
                   |unique_ptr's move           |unique_ptr's move
                   |constructor                 |constructor
      Known to fail|                            |4.6.4, 4.7.3, 4.9.0

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Backporting this fix is hard as it depends on some of the re-org done on trunk,
in particular doing dataref group analysis before dependence analysis, and then
especially marking those stmts as not vectorizable that do not participate in
a group.  Also looking closer this isn't fixed on trunk fully either because
if you trick group analysis to succeed but in the end vectorization not
because you let SLP build fail then we still miscompile it:

extern void abort (void);

static struct X { void *a; void *b; } a, b;

void __attribute__((noinline)) foo (void)
{
  void *tem = a.b;
  a.b = (void *)0;
  b.b = tem;
  b.a = a.a;
  a.a = tem;
}

int main()
{
  a.b = &a;
  foo ();
  if (b.b != &a)
    abort ();
  return 0;
}


t.c:7:9: note: === vect_analyze_slp ===
t.c:7:9: note: Build SLP for a.a = tem_2;

t.c:7:9: note: Build SLP for a.b = 0B;

t.c:7:9: note: Build SLP failed: different operation in stmt a.b = 0B;

in this case a missed optimization, of course.


Btw, 4.7.3 and 4.6.4 don't work for me for either testcase (they may work
for the original C++ testcase).  Wasn't able to check 4.5 right now
(but it has SLP vectorization, too).

[Bug tree-optimization/59374] [4.7/4.8/4.9 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.5.4

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Jakub bisected the regression for the testcase in comment #3 to r163757. 
Meanwhile verified that 4.5.4 works.

[Bug tree-optimization/59374] [4.7/4.8 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.9.0
            Summary|[4.7/4.8/4.9 Regression]    |[4.7/4.8 Regression]
                   |-ftree-slp-vectorize breaks |-ftree-slp-vectorize breaks
                   |unique_ptr's move           |unique_ptr's move
                   |constructor                 |constructor
      Known to fail|4.9.0                       |

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Now hopefully really fixed on trunk ;)

[Bug tree-optimization/59374] [4.7/4.8/4.9 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Jan 10 13:07:42 2014
New Revision: 206523

URL: http://gcc.gnu.org/viewcvs?rev=206523&root=gcc&view=rev
Log:
2014-01-10  Richard Biener  <rguenther@suse.de>

    PR tree-optimization/59374
    * tree-vect-slp.c (vect_slp_analyze_bb_1): Move dependence
    checking after SLP discovery.  Mark stmts not participating
    in any SLP instance properly.

    * gcc.dg/torture/pr59374-3.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr59374-3.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vect-slp.c

[Bug tree-optimization/59374] [4.7/4.8 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.3                       |4.8.4

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 4.8.3 is being released, adjusting target milestone.

[Bug tree-optimization/59374] [4.8 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mehta at roguewave dot com

--- Comment #12 from Paolo Carlini <paolo.carlini at oracle dot com> ---
*** Bug 61863 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/59374] [4.8 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug tree-optimization/59374] [4.8 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.4                       |4.8.5

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.8.4 has been released.

[Bug tree-optimization/59374] [4.8 Regression] -ftree-slp-vectorize breaks unique_ptr's move constructor

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59374

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|4.8.5                       |4.9.0
      Known to fail|                            |4.8.5

--- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed for 4.9.0.