On Tue, Oct 09, 2012 at 08:31:47AM -0700, Richard Henderson wrote:
> On 10/09/2012 08:16 AM, Aurelien Jarno wrote:
> >> > +static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
> >> > +{
> >> > + int sum = 0;
> >> > + sum += temps[p1[0]].state == TCG_TEMP_CONST;
> >> > + sum += temps[p1[1]].state == TCG_TEMP_CONST;
> >> > + sum -= temps[p2[0]].state == TCG_TEMP_CONST;
> >> > + sum -= temps[p2[1]].state == TCG_TEMP_CONST;
> >> > + if (sum > 0) {
> ...
> > Same comment are for the swap_commutative() patch, otherwise:
>
> While I don't have an explicit test case for swap_commutative2 like
> I do for swap_commutative, think about how many conditionals you'd
> have to use to write this without using SUM:
>
> if (((temps[p1[0]].state == TCG_TEMP_CONST // if both p1 are
> const
> && temps[p1[1]].state == TCG_TEMP_CONST
> && !(temps[p2[0]].state == TCG_TEMP_CONST // ... and not both
> p2 are const
> && temps[p2[1]].state == TCG_TEMP_CONST))
> || ((temps[p1[0]].state == TCG_TEMP_CONST // if either p1 are
> const
> || temps[p1[1]].state == TCG_TEMP_CONST)
> && !temps[p2[0]].state == TCG_TEMP_CONST // ... and neither p2
> are const
> && !temps[p2[1]].state == TCG_TEMP_CONST))
>
> I don't see how that can possibly be easier to understand.
>
>
For that one I agree.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
[email protected] http://www.aurel32.net
