[PATCH] D105398: [SCEVExpander] Support opaque pointers

[Nikita Popov via Phabricator via llvm-commits]

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This adds support for opaque pointers to `expandAddToGEP()` by always generating an i8 GEP for opaque pointers. After looking at some other cases (constexpr GEP folding, SROA GEP generation), I've come around to the idea that we should use i8 GEPs for opaque pointers, because the alternative would be to guess a GEP type from surrounding code, which will not be reliable. Ultimately, i8 GEPs is where we want to end up anyway, and opaque pointers just make that the natural choice.

(There are a couple of other places in SCEVExpander that check pointer element types, I plan to update those when I run across usable test coverage that doesn't assert elsewhere.)


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D105398

Files:
  llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
  llvm/test/Transforms/LoopStrengthReduce/opaque-ptr.ll

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