SIMD support...

[Martin Nowak]

On Sun, 08 Jan 2012 18:56:04 +0100, Peter Alexander  
<peter.alexander.au at gmail.com> wrote:

> On 8/01/12 5:02 PM, Martin Nowak wrote:
>> simdop will need more overloads, e.g. some
>> instructions need immediate bytes.
>> z = simdop(SHUFPS, x, y, 0);
>>
>> How about this:
>> __v128 simdop(T...)(SIMD op, T args);
>
> These don't make a lot of sense to return as value, e.g.
>
> __v128 a, b;
> a = simdop(movhlps, b); // ???
>
> movhlps moves the top 64-bits of b into the bottom 64-bits of a. Can't  
> be done as an expression like this.
>
> Would make more sense to just write the instructions like they appear in  
> asm:
>
> simdop(movhlps, a, b);
> simdop(addps, a, b);
> etc.
>
Yeah, also thought of this. Having a copy as default would
require to eliminate them again.

> The difference between this and inline asm would be:
>

> 1. Registers are automatically allocated.
See asm pseudo-registers.

> 2. Loads/stores are inserted when we spill to stack.
There are sequencing point before and after asm blocks.

> 3. Instructions can be scheduled and optimised by the compiler.
Optimization can be done on IR level.
Scheduling is done after all code is emitted.