[PATCH] D153744: [LoopUnroll] adjust for new `convergent` semantics

[Sameer Sahasrabuddhe via Phabricator via llvm-commits]

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Adjust the unrolling check for the new semantics:

- There is no restriction on loops with convergent operations that are controlled inside the loop -- their behavior with respect to cross-thread communication is (partially) implementation-defined, and the loop unrolling is part of the implementation, so...

- Fix unrolling with loop heart intrinsics: in a typical loop with a loop heart in the header that uses a token from outside the loop, duplicating the intrinsic would introduce multiple static uses of a convergence control token in a cycle that does not contain its definition.

Spell out the setup of UnrollLoopOptions to reduce the potential for
confusion caused by very long struct initializers.

Original implementation [D85605 <https://reviews.llvm.org/D85605>] by Nicolai Haehnle <nicolai.haehnle at amd.com>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D153744

Files:
  llvm/include/llvm/Analysis/CodeMetrics.h
  llvm/include/llvm/Transforms/Utils/UnrollLoop.h
  llvm/lib/Analysis/CodeMetrics.cpp
  llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
  llvm/lib/Transforms/Scalar/LoopUnrollAndJamPass.cpp
  llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
  llvm/lib/Transforms/Utils/LoopUnroll.cpp
  llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
  llvm/test/Transforms/LoopUnroll/convergent.controlled.ll

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