Re: Improved Swapping Method In sort.c

Jan Engelhardt
2008-04-30T17:30:57Z

On Wednesday 2008-04-30 19:09, Soumyadip Das Mahapatra wrote:

>Hello everybody, The swapping method (in function void u32_swap() line no.. 14
>to 16) in lib/sort.c can be improved by using the following code *(u32 *)b ^=
>*(u32 *)a ^= *(u32 *)b ^= *(u32 *)a instead of the code given.

GCC is smart enough to optimize the current instructions into a
bswap instruction or similar. While with xor, some are said to fail -
and three xor operations are surely slower than a swap if there is
a swap instruction.

Never heard of that?