https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97273
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
Known to work| |7.5.0
Target Milestone|--- |8.5
Last reconfirmed| |2020-10-02
Known to fail| |10.2.1, 11.0, 8.4.1, 9.3.1
Status|UNCONFIRMED |NEW
Summary|Strange behaviour of |[8/9/10/11 Regression]
|unordered_set when vector |Strange behaviour of
|is included (i686) |unordered_set when vector
| |is included (i686)
Ever confirmed|0 |1
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I've been trying to reduce this a bit. So far I've cut it down to:
#include <bits/stl_algobase.h>
#include <bits/allocator.h>
#include <bits/stl_construct.h>
#include <bits/stl_uninitialized.h>
#include <bits/stl_vector.h>
#include <unordered_set>
#include <cstdint>
uint64_t getBegin(const std::unordered_set<uint64_t> & set) {
return *set.begin();
}
which is less than everything in <vector> and still generates the bad code:
_3 = MEM[(const long long unsigned int &)_4 + 4];
The problem appeared between gcc 7 and gcc 8, apparently due to something added
in the libstdc++ headers. But I'm not sure yet if the actual bug is in the
compiler or library.
