Messages in this thread | | | Subject | Re: [PATCH] C undefined behavior fix | From | Alexandre Oliva <> | Date | 03 Jan 2002 16:44:14 -0200 |
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On Jan 2, 2002, David Woodhouse <dwmw2@infradead.org> wrote:
> VANDROVE@vc.cvut.cz said: >> (and for CONSTANT < 5 it of course generated correct code to fill dst >> with string contents; and yes, I know that code will sigsegv on run >> because of dst is not initialized - but it should die at runtime, not >> at compile time).
> An ICE, while it's not quite what was expected and it'll probably get fixed, > is nonetheless a perfectly valid implementation of 'undefined behaviour'.
Not really. Think of code whose execution is guarded by a test that guarantees it won't invoke undefined behavior, but whose test is in a separate translation unit. Or even of code that is never executed. The compiler has no business telling whether the code may potentially invoke undefined behavior, or whether it's going to be executed at all, it has to compile it to something that does whatever it wishes *if* it's executed. So, it should indeed die at runtime, not at compile time.
-- Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/ Red Hat GCC Developer aoliva@{cygnus.com, redhat.com} CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org} Free Software Evangelist *Please* write to mailing lists, not to me - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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