[llvm-commits] Source register same as write-back base

[Jakob Stoklund Olesen]

On Apr 12, 2011, at 1:02 PM, Joe Abbey wrote:

> 
>> What kind of code is producing this instruction? It seems odd to store
> a pointer to itself:
>> *p++ = p;
> 
> STL:
> 
> #include <vector>
> #include <list>
> 
> using namespace std;
> 
> int main(void)
> {
>    list<int> intList;
> 	vector<list<int> > vectorOfLists;
> 	vectorOfLists.push_back(intList);
> 	
> 	return 0;
> }

Ah, that makes sense, std::list is probably implemented as a circular list.

It seems that fast-isel doesn't generate the *_POST variants of stores, so there is no harm in adding @earlyclobber constraints to those instructions.

Do you know exactly which instructions have this constraint?

/jakob