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Is this an useful optimization ??Is this an useful optimization ??Posted Apr 18, 2008 21:22 UTC (Fri) by mikov (subscriber, #33179)In reply to: Is this an useful optimization ?? by ibukanov Parent article: GCC and pointer overflows
Exactly my point. It is not easy to imagine a case where this is a _desirable_ optimization.
It is either a bug, which should be warned, or it is deliberate. Either way the compiler
should not remove the code!
I imagine however that the general assumption "int + positive_value is always greater than
int" may be useful for complex loop optimizations and the like. It probably allows to
completely ignore integer overflow in cases like this "for (int i = 0; i < x; ++i ) {...}".
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Is this an useful optimization ?? Posted Apr 18, 2008 22:29 UTC (Fri) by nix (subscriber, #2304) [Link] That's equally useful for pointer arithmetic. Think arrays, strings, pointer walks, even things like Floyd's algorithm (smart optimizers can even spot the relationship between the tortoise and the hare: allowing for the hare to wrap around would ruin that).
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