ancient@nickolaypc ~ % valgrind ./a.out
==9016== Memcheck, a memory error detector
==9016== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==9016== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==9016== Command: ./a.out
==9016== 
vex x86->IR: unhandled instruction bytes: 0x67 0xE8 0x7B 0x68
==9016== valgrind: Unrecognised instruction at address 0x400301f.
==9016==    at 0x400301F: dl_main (in /usr/lib/ld-2.25.so)
==9016==    by 0x4016A25: _dl_sysdep_start (in /usr/lib/ld-2.25.so)
==9016==    by 0x4001861: _dl_start (in /usr/lib/ld-2.25.so)
==9016==    by 0x4000AF6: ??? (in /usr/lib/ld-2.25.so)
==9016== Your program just tried to execute an instruction that Valgrind
==9016== did not recognise.  There are two possible reasons for this.
==9016== 1. Your program has a bug and erroneously jumped to a non-code
==9016==    location.  If you are running Memcheck and you just saw a
==9016==    warning about a bad jump, it's probably your program's fault.
==9016== 2. The instruction is legitimate but Valgrind doesn't handle it,
==9016==    i.e. it's Valgrind's fault.  If you think this is the case or
==9016==    you are not sure, please let us know and we'll try to fix it.
==9016== Either way, Valgrind will now raise a SIGILL signal which will
==9016== probably kill your program.
==9016== 
==9016== Process terminating with default action of signal 4 (SIGILL): dumping core
==9016==  Illegal opcode at address 0x400301F
==9016==    at 0x400301F: dl_main (in /usr/lib/ld-2.25.so)
==9016==    by 0x4016A25: _dl_sysdep_start (in /usr/lib/ld-2.25.so)
==9016==    by 0x4001861: _dl_start (in /usr/lib/ld-2.25.so)
==9016==    by 0x4000AF6: ??? (in /usr/lib/ld-2.25.so)
==9016== 
==9016== HEAP SUMMARY:
==9016==     in use at exit: 0 bytes in 0 blocks
==9016==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==9016== 
==9016== All heap blocks were freed -- no leaks are possible
==9016== 
==9016== For counts of detected and suppressed errors, rerun with: -v
==9016== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
[1]    9016 illegal hardware instruction (core dumped)  valgrind ./a.out