[Bug libstdc++/82558] [8 Regression] V8 JavaScript engine segfaults since r249235

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82558

--- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
Created attachment 42371
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42371&action=edit
-fsanitize=undefined output

I have attached the -fsanitize=undefined output prior to the crash.
As you can see V8 wallows in UB. 
So I'm not sure if this is a libstdc++ bug or not.