[llvm-dev] Heap Exhaustion during 'DAGCombiner::Run'

Martin J. O'Riordan via llvm-dev llvm-dev at lists.llvm.org
Sun Feb 25 06:36:25 PST 2018

Hi LLVM-Devs,

I am in the process of updating our out-of-tree implementation from v5.0 to
v6.0 RC3, and while it builds and mostly runs, I am having trouble with a
small number of tests where the 'WorklistMap' in 'DAGCombiner::Run' never
becomes empty.  This is resulting in a runaway state of continuous heap
allocation until the process exhausts all system memory.

But I can't get a handle on why it is doing this, and it is not obvious to
me that the changes between v5.0 and v6.0 RC3 invalidate our implementation
in a way that might cause this.  The only time I see our code entered is
when lowering is called for vector element insert by 'LegalizeOp'.  Does
anybody have an advice on how I should approach debugging this?



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