[PATCH] D105510: [ScalarEvolution] Strictly enforce pointer/int type rules.

[Eli Friedman via Phabricator via llvm-commits]

efriedma created this revision.
efriedma added reviewers: reames, mkazantsev, nikic, lebedev.ri.
Herald added subscribers: javed.absar, hiraditya.
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Rules:

1. SCEVUnknown is a pointer if and only if the LLVM IR value is a pointer.
2. SCEVPtrToInt is never a pointer.
3. If any other SCEV expression has no pointer operands, the result is an integer.
4. If a SCEVAddExpr has exactly one pointer operand, the result is a pointer.
5. If a SCEVAddRecExpr's first operand is a pointer, and it has no other pointer operands, the result is a pointer.
6. If a SCEVMinMaxExpr has all pointer operands, the result is a pointer.
7. Otherwise, the SCEV expression is invalid.

I'm not sure how useful rule 6 is in practice.  If we exclude it, we can guarantee that ScalarEvolution::getPointerBase always returns a SCEVUnknown, which might be a helpful property. Anyway, I'll leave that for a followup.

This is basically mop-up at this point; all the changes with significant functional effects have landed.  Some of the remaining changes could be split off, but I don't see much point.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D105510

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
  llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
  llvm/unittests/Analysis/ScalarEvolutionTest.cpp

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