[More Info] Increasing speed of D applications to Intel C compiled applicaitons' standards

[Dave]

Dave wrote:
> Sean Kelly wrote:
>> Dave wrote:
>>>
>>> Could it be that Intel is doing whole program optimization to inline 
>>> things like memcpy and memset, during linkage (Are you using WPO? -- 
>>> it may be the default, I can't remember)? I've found that for time 
>>> critical code I can code my own (e.g.: memset) in D so the compiler 
>>> can inline it and it will be faster. Perhaps those should be in 
>>> Phobos instead of the C lib.?
>>
>> I've been thinking about this as well.  These functions are possibly a 
>> bit much for intrinsics, but it would be fairly trivial to write them 
>> in native D or even assembler--would have to inspect the resulting 
>> compiled code to see which was better.  The only problem offhand is 
>> that DMD does not inline functions containing loops, nor does it 
>> inline functions containing ASM blocks, so we'd probably be stuck with 
>> a function call even with native D code.
>>
> 
> Good points - I'd forgotten about not inlining loops.. The way I've 
> "inlined" things like memset() is to just write a foreach if needed.
> 

BTW - Since performance has come up a lot lately.. The reason one has to write the loop to get the 
most out of a simple memset type operation is because things like arr[100..200] = 0; are replaced by 
a call to memset anyhow. This is something that the compiler really should treat like an intrinsic IMO.

>> Sean