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> Chapter 14 is twenty-four carat gold Maybe, but the bounds-checking optimisation [14.2] just looks dangerous. If you end up with an erroneous 'int' index of
by nly 11y ago
> Chapter 14 is twenty-four carat gold
Maybe, but the bounds-checking optimisation [14.2] just looks dangerous. If you end up with an erroneous 'int' index of -1 then the original code will error out, whereas the new code will interpret it as 2^32 - 1. This is a perfectly valid index in an array of 2^32 values. This optimisation just isn't equivalent if INT_MAX < size <= UINT_MAX.
Am I missing something?
- deleted 11y ago[deleted]
- VodkaInferno 11y agosize is a const int that holds a positive value so you won't ever have INT_MAX < size.
- nly 11y agoYes, and the compiler knows that as well. GCC even merges the two versions because they're equivalent[0] My point is, if size is dynamic, this is a dangerous optimisation. [0] http://goo.gl/4Ev8as http://goo.gl/4Ev8as