[Bug middle-end/64922] [5 Regression] runtime error: member call on misaligned address for type 'struct _Rep'

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64922

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, with the patch you've posted I get:
$ /usr/src/gcc/obj/gcc/g++ -B /usr/src/gcc/obj/gcc/
`/usr/src/gcc/obj/x86_*/libstdc++-v3/scripts/testsuite_flags --build-includes`
-E -o x.ii x.cc -O2 -D_GLIBCXX_USE_CXX11_ABI=0
$ /usr/src/gcc/obj/gcc/cc1plus -fsanitize=alignment,bool,enum,unreachable -O2
x.ii  -quiet
$ gcc -o x x.s
/usr/src/gcc/obj/x86_64-unknown-linux-gnu/libsanitizer/ubsan/.libs/libubsan.a
-lpthread -ldl
/usr/src/gcc/obj/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so
-Wl,-rpath,/usr/src/gcc/obj/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs/
$ ./pol6 a
x.cc:39:3: runtime error: execution reached a __builtin_unreachable() call

And the unreachable calls in there are IMHO wrong.