On 19/09/14 00:56, Ian Lance Taylor wrote: > On Thu, Sep 18, 2014 at 2:15 AM, Ali Abdul Ghani <blade.vp2020@xxxxxxxxx> wrote: >> >> I have a question >> I read about register variables >> gcc Support register variables?? >> >> or treat him like any other variable?? > > In GCC the only meanings of the register qualifier are that you can't > the address of a register variable, and as a GCC extension you can > declare the specific register that the variable should go into. > I believe the register qualifier is used as a hint when you compile without optimisation, and will encourage the compiler to put the variable in a register rather than on the stack. The hint is ignored when optimising - they are treated as any other variable (other than making it illegal to take an address), as the compiler will do a better job of allocating variables to registers than a human would. David
