[Bug c++/65017] New: valgrind error in get_constraint_for_address_of

[Bug c++/65017] New: valgrind error in get_constraint_for_address_of

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65017

            Bug ID: 65017
           Summary: valgrind error in  get_constraint_for_address_of
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com

Created attachment 34722
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34722&action=edit
C++ source code

Given the C++ source code from bug # 47903, compiled
by trunk of 20150211 with flag -O2, then valgrind
says

==22708== Conditional jump or move depends on uninitialised value(s)
==22708==    at 0xD708FD: get_constraint_for_address_of
(tree-ssa-structalias.c:
3370)
==22708==    by 0xD708FD: get_constraint_for_1(tree_node*, vec<constraint_expr, 
va_heap, vl_ptr>*, bool, bool) (tree-ssa-structalias.c:3434)
==22708==    by 0xD743C9: get_constraint_for_rhs (tree-ssa-structalias.c:3580)
==22708==    by 0xD743C9: make_constraint_to(unsigned int, tree_node*)
(tree-ssa
-structalias.c:3703)

tree-ssa-structalias.c:3370 is

      if (c->type == DEREF)

[Bug c++/65017] valgrind error in get_constraint_for_address_of

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65017

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2015-02-11
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mine.

[Bug c++/65017] valgrind error in get_constraint_for_address_of

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65017

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
I can't reproduce this - how did you compile/configure GCC?  Just tried both
--enable-checking and --enable-checking=release builds.

[Bug c++/65017] valgrind error in get_constraint_for_address_of

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65017

--- Comment #3 from David Binderman <dcb314 at hotmail dot com> ---
(In reply to Richard Biener from comment #2)
> I can't reproduce this - how did you compile/configure GCC?  Just tried both
> --enable-checking and --enable-checking=release builds.

../src/trunk/configure --prefix=/home/dcb/gcc/results \
    --disable-bootstrap \
    --disable-werror \
    --enable-checking=yes \
    --enable-languages=c,c++,fortran \
    CC="clang -fheinous-gnu-extensions" \
    CXX="clang++ -fheinous-gnu-extensions"

on AMD Phenom.

[Bug c++/65017] valgrind error in get_constraint_for_address_of

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65017

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |WAITING

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #4)
> On Wed, 11 Feb 2015, dcb314 at hotmail dot com wrote:
> 
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65017
> > 
> > --- Comment #3 from David Binderman <dcb314 at hotmail dot com> ---
> > (In reply to Richard Biener from comment #2)
> > > I can't reproduce this - how did you compile/configure GCC?  Just tried both
> > > --enable-checking and --enable-checking=release builds.
> > 
> > ../src/trunk/configure --prefix=/home/dcb/gcc/results \
> >     --disable-bootstrap \
> >     --disable-werror \
> >     --enable-checking=yes \
> >     --enable-languages=c,c++,fortran \
> >     CC="clang -fheinous-gnu-extensions" \
> >     CXX="clang++ -fheinous-gnu-extensions"
> > 
> > on AMD Phenom.
> 
> Uh, so it might be very well clang miscompiling it.  I don't have
> clang to reproduce, so can you get me some more information,
> like
> 
> (gdb) p debug_tree (t)
> 
> at the point it barfs?  Can you disable optimization of clang?
> Thus build with CFLAGS="-g -O0" CXXFLAGS="-g -O0"?

Can't reproduce when building GCC with clang 3.3 like you specified above.

[Bug c++/65017] valgrind error in get_constraint_for_address_of

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65017

--- Comment #6 from David Binderman <dcb314 at hotmail dot com> ---
(In reply to Richard Biener from comment #5)
> Can't reproduce when building GCC with clang 3.3 like you specified above.

I removed clang from the configure of gcc, rebuilt gcc, tried again
and the problem went away !

A version of clang > 3.3 but <= 3.5 looks to be the culprit.

[Bug c++/65017] valgrind error in get_constraint_for_address_of

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65017

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|---                         |INVALID

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Thans for checking.