https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101210
Bug ID: 101210
Summary: [7/8/9/10/11/12 regression] spurious "reference
binding to misaligned address" ubsan error for integer
comparison
Product: gcc
Version: 11.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jlegg at feralinteractive dot com
Target Milestone: ---
With -fsanitize=undefined, this C++ code:
int main()
{
int x;
int & y {x};
return reinterpret_cast<long int>(&y) == 1;
}
Produces this error at runtime:
test.cc:5:40: runtime error: reference binding to misaligned address
0x000000000001 for type 'int', which requires 4 byte alignment
0x000000000001: note: pointer points here
<memory cannot be printed>
However, address 1 is never bound to a reference to an int. It is an integer
which is compared to another integer (which happens to be pointer sized and
derived from an address taken from a reference).
Checking various versions with compiler explorer, GCC 6 did not have this
issue, but later releases did.
