I believe the exception ban at Google these days is justified more on the grounds that integrating with existing code would be problematic, rather than on performance grounds. I seem to remember reading something to that effect.
That may be the explanation they've settled on but there are build artifacts at that company which would be impossible to link without -fno-exceptions, so there are also practical problems.
This is correct. Google have many, many million lines of casually exception-unsafe code they cannot afford to fix, so any rationalization is only that. The choice is off the table.
