[PATCH] D72148: [DSE] Support traversing MemoryPhis.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: dmgreen, rnk, efriedma, bryant, asbirlea.
Herald added subscribers: george.burgess.iv, hiraditya.
Herald added a project: LLVM.

For MemoryPhis, we have to avoid that the MemoryPhi may be executed
before before the access we are currently looking at.

To do this we do a post-order numbering of the basic blocks in the
function and bail out once we reach a MemoryPhi with a larger (or equal)
post-order block number than the current MemoryAccess.

This changes the order in which we visit stores for elimination.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D72148

Files:
  llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
  llvm/test/Transforms/DeadStoreElimination/MSSA/memoryssa-debugcounter.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-loops.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-memoryphis.ll

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