[Bug sanitizer/104934] New: -fsanitize=undefined codegen err

["dimhen at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104934

            Bug ID: 104934
           Summary: -fsanitize=undefined codegen err
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dimhen at gmail dot com
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at gcc dot gnu.org
  Target Milestone: ---

r12-7608 FAIL

Probably FAIL long ago: gcc-8 FAIL
gcc version 8.0.1 20180125 (experimental) [trunk revision 257061] (GCC)


$ g++ -fsanitize=undefined -c -o x.o x.ii && nm -u --reverse-sort x.o
                 U _ZTI1S
$ g++ -c -o x.o x.ii && nm -u --reverse-sort x.o

$ cat x.ii
struct a {};
struct b {
  a c;
};
struct S : a {
  virtual int d();
};
struct e : b {
  unsigned f();
};
unsigned e::f() { static_cast<S *>(&c); return 0; }

$ ~/arch-gcc/gcc_current/bin/g++ -v
Using built-in specs.
COLLECT_GCC=/home/dimhen/arch-gcc/gcc_current/bin/g++
COLLECT_LTO_WRAPPER=/home/dimhen/arch-gcc/gcc_current/libexec/gcc/x86_64-pc-linux-gnu/12.0.1/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
Target: x86_64-pc-linux-gnu
Configured with: /home/dimhen/src/gcc_current/configure
--prefix=/home/dimhen/arch-gcc/gcc_current
--enable-checking=yes,df,fold,rtl,extra --enable-languages=c,c++,lto
--disable-multilib --enable-shared --enable-threads=posix --enable-__cxa_atexit
--enable-gnu-unique-object --enable-linker-build-id
--with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl
--enable-offload-targets=nvptx-none --without-cuda-driver
--enable-gnu-indirect-function --enable-cet --with-tune=native
--enable-libstdcxx-debug
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.1 20220311 (experimental) [master r12-7608-g5e28be89665] (GCC)