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Re: __assert_fail should not be __attribute__((__noreturn__))
On Montag, 5. April 2004 19:30, Richard Henderson wrote:
> On Sun, Apr 04, 2004 at 10:46:09PM -0400, Daniel Jacobowitz wrote:
> > You might want to look at what GCC can use the noreturn marker for.
> > Branch prediction and block reordering, for instance.
>
> Actually, the most important thing is that GCC can prove that the
> assert condition is false after the assertion. This knowledge gets
> propagated into following statements.
These optimization opportunities are only available if assert() is used, but
NDEBUG is _not_ used. That is, the optimzed code is payed with the runtime
needed to evaluate the condition.
This makes no sense to me. I still think that if performance is needed,
-DNDEBUG is the best optimization.
Is there so much software that benefits from unelided assert() expressions
that removing noreturn is not an option?
-- Hannes