[Bug libstdc++/64632] New: runtime error: member call on address 0x0000004318a8 which does not point to an object of type 'ios_base'

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64632

            Bug ID: 64632
           Summary: runtime error: member call on address 0x0000004318a8
                    which does not point to an object of type 'ios_base'
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org

Created attachment 34465
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34465&action=edit
testcase

markus@x4 ~ % g++ -fsanitize=undefined -O2 bench.cpp
markus@x4 ~ % ./a.out
size            array   vector_point    vector_iters            deque          
list            set             multiset
/usr/lib/gcc/x86_64-pc-linux-gnu/5.0.0/include/g++-v5/bits/ios_base.h:1037:16:
runtime error: member call on address 0x0000004318a8 which does not point to an
object of type 'ios_base'
0x0000004318a0: note: object is base class subobject at offset 8 within object
of type 'std::ostream'
 00 00 00 00  a8 17 ce 25 ca 7f 00 00  d0 17 ce 25 ca 7f 00 00  06 00 00 00 00
00 00 00  00 00 00 00
              ^                        ~~~~~~~~~~~~~~~~~~~~~~~
                                       vptr for '<unknown>' base class of
'std::ostream'
/usr/lib/gcc/x86_64-pc-linux-gnu/5.0.0/include/g++-v5/iomanip:210:7: runtime
error: member call on address 0x0000004318a8 which does not point to an object
of type 'ios_base'
0x0000004318a0: note: object is base class subobject at offset 8 within object
of type 'std::ostream'
 00 00 00 00  a8 17 ce 25 ca 7f 00 00  d0 17 ce 25 ca 7f 00 00  06 00 00 00 00
00 00 00  00 00 00 00
              ^                        ~~~~~~~~~~~~~~~~~~~~~~~
                                       vptr for '<unknown>' base class of
'std::ostream'
10              0.23            0.23            0.41            0.77           
1.57            0.97            1.44
^C


markus@x4 ~ % clang++ -fsanitize=undefined -O2 bench.cpp
markus@x4 ~ % ./a.out
size            array   vector_point    vector_iters            deque          
list            set             multiset
/usr/lib64/gcc/x86_64-pc-linux-gnu/5.0.0/include/g++-v5/bits/ios_base.h:102:24:
runtime error: load of value 4294967035, which is not a valid value for type
'std::_Ios_Fmtflags'
/usr/lib64/gcc/x86_64-pc-linux-gnu/5.0.0/include/g++-v5/bits/ios_base.h:82:67:
runtime error: load of value 4294967035, which is not a valid value for type
'std::_Ios_Fmtflags'
10              0.26            0.28            0.51            2.13           
3.81            1.26            2.04
^C