This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: An unusual Performance approach using Synthetic registers
On Monday 06 January 2003 01:47 am, Andy Walker wrote:
>
> The list of instructions that might operate on a Synthetic register is
> short: mov, add, sub, neg, and, or, xor, ror, rol, ashl, ashr, and lshr
> (sp?). In addition, a synthetic register may be a source for a mul or
> divmod. For this short list of instructions, a Synthetic register can be a
> source or destination, in conjunction with a register, or it may be a
> destination in conjunction with an immediate value.
>
Andy,
Is it possible to define a two-ouput instruction?
If so, add XCHG to your list, short, fast, works in any pipeline, and
can substitute for a pair of moves. (Three, if you have to supply
your own temporary.)
Mike