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[Bug libstdc++/83906] [8 Regression] Random FAIL: libstdc++-prettyprinters/80276.cc whatis p4
- From: "palves at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 23 Jan 2018 17:15:44 +0000
- Subject: [Bug libstdc++/83906] [8 Regression] Random FAIL: libstdc++-prettyprinters/80276.cc whatis p4
- Auto-submitted: auto-generated
- References: <bug-83906-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83906
--- Comment #11 from Pedro Alves <palves at redhat dot com> ---
Running the testcase under valgrind and current gdb master I see:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
==6118== Conditional jump or move depends on uninitialised value(s)
==6118== at 0x4C35CB0: bcmp (vg_replace_strmem.c:1100)
==6118== by 0x6F773A: check_types_equal(type*, type*,
VEC_type_equality_entry_d**) (gdbtypes.c:3515)
==6118== by 0x6F7B00: check_types_worklist(VEC_type_equality_entry_d**,
bcache*) (gdbtypes.c:3618)
==6118== by 0x6F7C03: types_deeply_equal(type*, type*) (gdbtypes.c:3655)
==6118== by 0x4D5B06: typy_richcompare(_object*, _object*, int)
(py-type.c:1007)
==6118== by 0x63D7E6C: PyObject_RichCompare (object.c:961)
==6118== by 0x646EAEC: PyEval_EvalFrameEx (ceval.c:4960)
==6118== by 0x646DC08: PyEval_EvalFrameEx (ceval.c:4519)
==6118== by 0x646DC08: PyEval_EvalFrameEx (ceval.c:4519)
==6118== by 0x646DC08: PyEval_EvalFrameEx (ceval.c:4519)
==6118== by 0x646DC08: PyEval_EvalFrameEx (ceval.c:4519)
==6118== by 0x646DC08: PyEval_EvalFrameEx (ceval.c:4519)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
AFAICT so far, looks like gdb is memcmp'ing two objects that only differ in
padding. Looks like objects of this type range_bounds are always memset when
allocated, so I'm not sure that is going on. (The type is trivial.)