[Bug c++/55418] New: Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[Bug c++/55418] New: Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[markus at trippelsdorf dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55418

             Bug #: 55418
           Summary: Valgrind: Conditional jump or move depends on
                    uninitialised value(s) in implicitly_declare_fn()
                    method.c:1623
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: markus@trippelsdorf.de


Just saw this during a -enable-checking=yes,valgrind build:

 % /var/tmp/gcc_valgrind/usr/local/bin/g++ -std=gnu++11 -c
/home/markus/gcc/libstdc++-v3/src/c++11/functexcept.cc
==1267== Conditional jump or move depends on uninitialised value(s)
==1267==    at 0x637C0F: implicitly_declare_fn(special_function_kind,
tree_node*, bool, tree_node*, tree_node*) (method.c:1623)
==1267==    by 0x6392DF: lazily_declare_fn(special_function_kind, tree_node*)
(method.c:1894)
==1267==    by 0x63FB74: lookup_fnfields_1(tree_node*, tree_node*)
(search.c:1441)
==1267==    by 0x63FD3B: lookup_fnfields_slot(tree_node*, tree_node*)
(search.c:1471)
==1267==    by 0x64367B: lookup_field_r(tree_node*, void*) (search.c:1031)
==1267==    by 0x6400CE: dfs_walk_all(tree_node*, tree_node* (*)(tree_node*,
void*), tree_node* (*)(tree_node*, void*), void*) (search.c:1572)
==1267==    by 0x6402E7: lookup_member(tree_node*, tree_node*, int, bool, int)
(search.c:1204)
==1267==    by 0x640640: lookup_fnfields(tree_node*, tree_node*, int)
(search.c:1295)
==1267==    by 0x4DF3B0: build_special_member_call(tree_node*, tree_node*,
vec<tree_node*, va_gc, vl_embed>**, tree_node*, int, int) (call.c:7282)
==1267==    by 0x4E0693: convert_like_real(conversion*, tree_node*, tree_node*,
int, int, bool, bool, int) (call.c:5718)
==1267==    by 0x4E1D91: build_over_call(z_candidate*, int, int) (call.c:6867)
==1267==    by 0x4DE229: build_new_method_call(tree_node*, tree_node*,
vec<tree_node*, va_gc, vl_embed>**, tree_node*, int, tree_node**, int)
(call.c:7668)
==1267== 

Looks like some booleans in implicitly_declare_fn should be initialised.

[Bug c++/55418] Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[markus at trippelsdorf dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55418

--- Comment #1 from Markus Trippelsdorf <markus at trippelsdorf dot de> 2012-11-21 14:08:12 UTC ---
The following trivial patch fixes the issue:

diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 6dcb63a..3cb4ace 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -1518,7 +1518,7 @@ implicitly_declare_fn (special_function_kind kind, tree
type,
   tree name;
   HOST_WIDE_INT saved_processing_template_decl;
   bool deleted_p;
-  bool trivial_p;
+  bool trivial_p = false;
   bool constexpr_p;

   /* Because we create declarations for implicitly declared functions

[Bug c++/55418] Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[hp at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55418

Hans-Peter Nilsson <hp at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hp at gcc dot gnu.org

--- Comment #2 from Hans-Peter Nilsson <hp at gcc dot gnu.org> 2012-11-21 15:51:08 UTC ---
I haven't (In reply to comment #1)
> The following trivial patch fixes the issue:

I haven't looked at the context so I feel free to say it looks a bit obvious...

[Bug c++/55418] Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55418

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-22 10:46:31 UTC ---
The issue seems indeed trivial, but note that we are already assigning false to
trivial_p in the conditional, thus I guess we should remove the latter. Maybe
also move the declaration itself right before the conditional, in my opinion it
adds clarity. Please send a patch to the mailing list.

[Bug c++/55418] Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[paolo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55418

--- Comment #4 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2012-11-23 15:34:51 UTC ---
Author: paolo
Date: Fri Nov 23 15:34:45 2012
New Revision: 193758

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193758
Log:
2012-11-23  Markus Trippelsdorf  <markus@trippelsdorf.de>

    PR c++/55418
    * method.c (implicitly_declare_fn): Properly initialize trivial_p.

Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/method.c

[Bug c++/55418] Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55418

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.8.0

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-23 15:35:55 UTC ---
Fixed.

[Bug c++/55418] Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55418

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dcb314 at hotmail dot com

--- Comment #6 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-12-05 11:42:05 UTC ---
*** Bug 52311 has been marked as a duplicate of this bug. ***

[Bug c++/55418] Valgrind: Conditional jump or move depends on uninitialised value(s) in implicitly_declare_fn() method.c:1623

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55418

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl.tools at gmail dot com

--- Comment #7 from Paolo Carlini <paolo.carlini at oracle dot com> ---
*** Bug 53224 has been marked as a duplicate of this bug. ***