On 9/10/2010 2:17 AM, Dave Martin wrote: > (int)((unsigned)c << 28) >> 28 > > is invalid C, because the result of the unsigned->signed cast (needed > to get arithmetic right shift) is undefined if the argument is > > INT_MAX.
True, but undefined-ness (or, in this case, implementation-defined-ness, IIRC) helps the compiler; it's free to do as it wants. So, this is no excuse for the compiler generating slow code. (In particular, the compiler needn't generate a test to see whether the argument is greater than INT_MAX.) -- Mark Mitchell CodeSourcery m...@codesourcery.com (650) 331-3385 x713 _______________________________________________ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
