[llvm-commits] [llvm] r84038 - in /llvm/trunk: lib/Analysis/BasicAliasAnalysis.cpp test/Analysis/BasicAA/phi-aa.ll

Nick Lewycky nicholas at mxc.ca
Wed Oct 14 11:57:36 PDT 2009

Evan Cheng wrote:
> On Oct 13, 2009, at 3:47 PM, Nick Lewycky wrote:
>> Evan, please put a recursion depth limit on the number of PHIs this code is willing to walk backwards through, otherwise pathological code will show n^2 behaviour.
> It stops when it sees a PHI source which is itself PHI. That should be sufficient, no?

I misread the patch and missed that part. I thought it was only stopping 
on cycles of the same PHI, but there's clearly code early on to prevent 
visiting phi-of-phi.


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