[LLVMdev] Should repetitive basic blocks be removed in the results of LoopBase::getExitBlocks()?

[Hongbin Zheng]

hi,


> Users generally expect a unique set of exit blocks, but don't make any
> strong assumption. The worst that can happen is missed optimization or
> redundant analysis. In most cases, the loop is in LoopSimplifyForm, so it's
> probably not a problem in practice.
>
>
> Another thing I should mention. The iteration order of ExitBlocks is
> important. In llvm, generating unique sets is a pain because values are not
> numbered and iteration order needs to be reproducible. We would need to keep
> a SmallPtrSet for membership checking while populating the result vector.
What about use the SetVector[1] as container? As its comment say:

This adapter class provides a way to keep a set of things that also
has the property of a deterministic iteration order. The order of
iteration is the order of insertion.

best regards
ether
[1]http://www.llvm.org/doxygen/classllvm_1_1SetVector.html
>
> -Andy
>
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