Friendly-C

deadalnix via Digitalmars-d digitalmars-d at puremagic.com
Fri Aug 29 10:34:41 PDT 2014


On Friday, 29 August 2014 at 17:33:14 UTC, Ola Fosheim Grøstad
wrote:
> On Friday, 29 August 2014 at 17:29:49 UTC, deadalnix wrote:
>> Indeed, undefined behavior can be anything, by definition, and 
>> this cannot. Still, removing undefined behavior and replace it 
>> by undefined values cause the optimizer to have to prove that 
>> load/store won't fault, which is going to kill any expectation 
>> of performance.
>
> I still don't understand what kind of fault your are talking 
> about.
>
> Granted if you store in more than one location you have to make 
> at least one move, but if you only store in one location you 
> have the same situation as if you are optimizing:
>
> a=a;
>
> Clearly you can remove this without doing any loads or stores?

No, as the load or the store involved can fault/trap.


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