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On Sat, Feb 10, 2007 at 03:09:41PM +0200, Robert Dewar wrote:
> Ian Lance Taylor wrote:
> > "Jie Zhang" <[EMAIL PROTECTED]> writes:
> >> But now gcc seems to optimize it away. For the following function:
> >>
> >> $ cat t.c
> >> #include <limits.h>
> >> void foo (int rc)
> >> {
> >> int x = rc / INT_MAX;
> >> x = 4 / x;
> >> }
> >
> > I believe we still keep division by zero in general. In your example
> > it gets optimized away because it is dead code. Nothing uses x.
Right. Sometimes it's tricky to remember that NOT reciting Hamlet's
soliloquy also qualifies as "undefined behaviour"! :)
> And it is certainly reasonable to do this optimization given that
> the result of the division is undefined in C.
There's nothing wrong with foo(INT_MAX). Or variants involving INT_MIN.
- --
A PC without Windows is like ice cream without ketchup.
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