[PATCH] D125292: [Coroutines] Introduce "coro_readnone" operand bundles (2/3)

[Chuanqi Xu via Phabricator via llvm-commits]

ChuanqiXu created this revision.
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This belongs to a series of patches which try to solve the thread identification problem in coroutines. See https://discourse.llvm.org/t/address-thread-identification-problems-with-coroutine/62015 for a full background.

This patch tries to solve the `readnone` problem by removing the `readnone` attributes for calls in a coroutine in CoroEarly pass. And we would add the `readnone` attribute back after the coroutine get split in CoroCleanup pass. To record the calls we removed the attribute and block unexpect optimizations, we introduced "coro_readnone" operand bundles.

Why operand bundles instead of another attribute on the callsite?

Since when the compiler query whether a call is `readnone`, it would try to lookup to the callee declaration of the call if it failed to find the attribute at the callsite. See https://github.com/llvm/llvm-project/blob/3b762b3ab8d205cd6a7d42c96d39d5f4f701f2ab/llvm/include/llvm/IR/InstrTypes.h#L2315-L2325


https://reviews.llvm.org/D125292

Files:
  llvm/docs/LangRef.rst
  llvm/include/llvm/IR/LLVMContext.h
  llvm/lib/IR/LLVMContext.cpp
  llvm/lib/Transforms/Coroutines/CoroCleanup.cpp
  llvm/lib/Transforms/Coroutines/CoroEarly.cpp
  llvm/lib/Transforms/Utils/InlineFunction.cpp
  llvm/test/Bitcode/operand-bundles-bc-analyzer.ll
  llvm/test/Transforms/Coroutines/coro-readnone-01.ll
  llvm/test/Transforms/Coroutines/coro-readnone-02.ll
  llvm/test/Transforms/Coroutines/coro-readnone-03.ll
  llvm/test/Transforms/Coroutines/coro-readnone-04.ll
  llvm/test/Transforms/Coroutines/coro-readnone-05.ll

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