[LLVMdev] LLVMdev Digest, Vol 77, Issue 41

[Chris Lattner]

On Nov 27, 2010, at 2:14 AM, Morten Ofstad wrote:

>> On Friday, November 26, 2010 4:32 PM
>> Jonas Paulsson <jnspaulsson at hotmail.com> wrote:
>> 
>> Well, the reason DSP compilers would benefit from the new type, is that 
>> fixed point numbers must not be optimized
>> as integers - eg if two saturated fixed point constants would overflow in 
>> an addition operation, the result should as
>> well be saturated. Doing this in a series of steps with intrinsics would 
>> be quite ridiculous as far as performance goes,
>> because this is _supported by the DSP in hardware_ in a single instruction 
>> :-)
> 
> Isn't it better to add instructions for saturated and/or fixed point 
> arithmetic? ... 

Yep. :)

-Chris