[PATCH] D80844: [TRE] Allow accumulator elimination when base case returns non-constant

[Layton Kifer via Phabricator via llvm-commits]

laytonio updated this revision to Diff 268004.
laytonio added a comment.

I added your example as a test case. It is worth noting that even at -O1 clang hoists and merges the recursive calls and then branches to the correct accumulator, which would prevent either from getting removed. Also, the multiply by 2 gets converted to a shift, which would also prevent that path from getting removed. I'm going to take a look at creating another patch after this to convert shifts back to multiplies if it would enable an elimination.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80844/new/

https://reviews.llvm.org/D80844

Files:
  llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
  llvm/test/Transforms/TailCallElim/accum_recursion.ll

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