[LLVMdev] Is infinite empty loop dead code?

[Shuxin Yang]

I do some google, I cannot find the answer...
I check C std, I cannot find answer either.

Delete infinite empty loop is boring, but if C/C++ lawyers could tell it 
is safe to to so,
it would obviate the need to prove a non-countable loop infinite or not 
before
DCE can delete it.

That is the answer I'm waiting for to delete a disgusting dead 
non-countable loop in my way.

On 11/14/2012 12:14 AM, Duncan Sands wrote:
> Hi Shuxin,
>
>>      Is it legal to delete empty infinite loop like this : "while(1) 
>> {}"?
>> It is interesting that both llvm and gcc keep the loop, however 
>> Open64 delete it.
>
> this is an endless source of discussion.  I suggest you read the GCC 
> and LLVM
> mailing list archives if you want to find out more about it.
>
> Ciao, Duncan.
>
>>     If it is safe to delete this loop, it would be lot easier to 
>> delete non-obvious
>> dead loop like following as compiler doesn't need to prove if the 
>> loop in question
>> is infinite or not. Currently llvm is not able to delete such dead loop.
>>
>>     while (a) { a = whatever } ; // no use of <a> after this point.
>>
>> Thanks
>>
>> Shuxin
>>
>>
>>
>>
>>
>>
>>
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