[PATCH] D37353: [SparsePropagation] Enable interprocedural analysis

[Matthew Simpson via Phabricator via llvm-commits]

mssimpso updated this revision to Diff 118830.
mssimpso added a comment.

Implement the previously discussed approach using generic LatticeKeys. A few things to note about this version of the patch:

First, there's a requirement that LatticeKeys are able to be the key_type of whatever mapping structure the generic solver uses internally (i.e., DenseMap). If a client uses a non-trivial type for LatticeKey, it will have to provide a specialization of DenseMapInfo. But we already have specializations for pointers and PointerIntPairs, which I think probably covers most potential clients. I've added a comment at the top of AbstractLatticeFunction mentioning this.

Second, there are cases when the generic solver needs to translate between LatticeKeys and their corresponding LLVM Values. One case is when it needs to add LLVM Values to the work list after the state of a LatticeKey changes. Another case is when the solver tries to determine the executable blocks, and needs to get the state of an LLVM Value (e.g., a branch or switch condition or phi node). It needs to know the LatticeKey of a Value before it can get its associated state. I originally thought about adding two virtual functions to AbstractLatticeFunction that would let the client define the conversions between LatticeKeys and LLVM Values. But I thought the overhead of the calls might be too large, especially for simple cases, like when the LatticeKey is just an LLVM Value. I instead went with a LatticeKeyInfo template that clients can specialize for their chosen LatticeKey type.

The test cases show how this works for simple ipa-cp-like problems. If the approach looks good, I'll update the summary and the CalledValuePropagation pass (https://reviews.llvm.org/D37355).


https://reviews.llvm.org/D37353

Files:
  include/llvm/Analysis/SparsePropagation.h
  unittests/Analysis/CMakeLists.txt
  unittests/Analysis/SparsePropagation.cpp

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