* Josh Poimboeuf <[email protected]> wrote:
> > > > Well, technically an invalid opcode is shorter code than generating an
> > > > (integer) division by zero exception, right?
> > >
> > > What does that matter if it's the wrong behavior?
> >
> > Well, both terminate the program, and it's obvious if you look at it with a
> > debugger what happened, right?
>
> If it were obvious, we wouldn't be having this discussion :-)
Touche ;-)
> The only thing obvious to me was that gcc mysteriously removed a bunch of
> code
> and replaced it with a 'ud2' instruction in the middle of the function for no
> apparent reason.
I don't know what their motivation was, but if it's not a bug, if it was done
intentionally, then I'd guess it's roughly the argument I made: in simple
testcases it can be argued to be a code size improvement, plus it's probably
allowed by the letter of the compiler standards (program termination behavior
is
notoriously platform dependent and thus vaguely specified) - but for real-life
code I very much agree that it's a step backward in generated code quality...
Thanks,
Ingo
