https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78487
--- Comment #5 from Stephan Beyer <s-beyer at gmx dot net> --- It crashes on run-time. I have absolutely no experience using extended asm syntax but I guess g++ relies on the constraints for its optimization, so I guess the constraints are wrong. I will port the code to use the macro from cpuid.h and close the issue if there are no more crashes. Thank you.