[PATCH] D72700: [DSE] Add first version of MemorySSA-backed DSE (Bottom up walk).

[Florian Hahn via Phabricator via llvm-commits]

fhahn updated this revision to Diff 242423.
fhahn marked 4 inline comments as done.
fhahn added a comment.

Addressed latest comments, thanks!

In D72700#1857699 <https://reviews.llvm.org/D72700#1857699>, @xbolva00 wrote:

> Just curious..
>
> Can you compare this solution vs. GCC's solution vs. PDSE (https://reviews.llvm.org/D29866)?


I unfortunately do not have in-depth knowledge of either, but I think GCC uses a similar approach (I think GCC's virtual operands are similar to MemorySSA).

IIUC PDSE tries to remove partially redundant stores, by inserting/moving stores to split points. I think that is mostly orthogonal to the MemorySSA-backed DSE in this patch, although there might be some overlap in the handled cases.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D72700/new/

https://reviews.llvm.org/D72700

Files:
  llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
  llvm/test/Transforms/DeadStoreElimination/MSSA/debuginfo.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/fence-todo.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/fence.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/memoryssa-scan-limit.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/memset-and-memcpy.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-captures.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-exceptions.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-loops.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-memoryphis.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-partial.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/multiblock-simple.ll
  llvm/test/Transforms/DeadStoreElimination/MSSA/simple.ll

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