[PATCH] D126089: [WPD] Make sure type test is eliminated

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added inline comments.


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Comment at: llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp:1929
+      if (!CI->use_empty())
+        CI->replaceAllUsesWith(ConstantInt::getTrue(M.getContext()));
       // We can't use RecursivelyDeleteTriviallyDeadInstructions here because we
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tejohnson wrote:
> The equivalent code in LowerTypeTests::lower() asserts that the users are all phi nodes in this case. Can you add the same check here?
that asserts on [1]. I'm not sure why the assert in LTT never triggers since it does seem like you could potentially do arbitrary things with the result of type tests. if we really wanted to make sure that type tests were only used by assumes, perhaps indirectly through phis, I think that would be more of a verifier check

[1] https://github.com/llvm/llvm-project/blob/8801a5d185fafcb8c03f71ceb717b84c2f08b220/llvm/test/ThinLTO/X86/cache-typeid-resolutions.ll#L32


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D126089/new/

https://reviews.llvm.org/D126089