On 2014-04-10 11:48:44 +0000, Thorsten Glaser wrote: > Ian Jackson dixit: > > >> If the architecture uses two's complement, however, then the code is > >> correct. > > > >Unfortunately adversarial optimisation by modern compilers means that > >this kind of reasoning is no longer valid. > > > >The compiler might easily see that your code unconditionally performs > >a computation with undefined behaviour, and delete it. > > And GCC is a repeat offender which actually does do that.
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