[PATCH] D81938: [SROA] Teach SROA to perform no-op pointer conversion.[InferAddressSpaces] Handle the pair of `ptrtoint`/`inttoptr`.

[Michael Liao via Phabricator via llvm-commits]

hliao created this revision.
hliao added reviewers: arsenm, chandlerc.
Herald added subscribers: llvm-commits, cfe-commits, kerbowa, hiraditya, nhaehnle, wdng, jvesely.
Herald added projects: clang, LLVM.

- When promoting a pointer from memory to register, SROA skips pointers from different address spaces. However, as `ptrtoint` and `inttoptr` are defined as no-op casts if that integer type has the same as the pointer value, generate the pair of `ptrtoint`/`inttoptr` (no-op cast) sequence to convert pointers from different address spaces if they have the same size.

- `ptrtoint` and `inttoptr` are defined as no-op casts if the integer value as the same size as the pointer value. The pair of `ptrtoint`/`inttoptr` is in fact a no-op cast sequence between different address spaces. Teach `infer-address-spaces` to handle them like a `bitcast`.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D81938

Files:
  clang/test/CodeGenCUDA/amdgpu-kernel-arg-pointer-type.cu
  llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
  llvm/lib/Transforms/Scalar/SROA.cpp
  llvm/test/Transforms/InferAddressSpaces/noop-ptrint-pair.ll
  llvm/test/Transforms/SROA/address-spaces.ll
  llvm/test/Transforms/SROA/alloca-address-space.ll

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