[PATCH] D124571: Avoid strict aliasing violation on type punning inside llvm::PointerIntPair

[Breno Rodrigues Guimaraes via Phabricator via llvm-commits]

brenoguim updated this revision to Diff 429495.
brenoguim added a comment.

Since `PointerIntPair` may hold non-trivially-constructible types (like another `PointerIntPair`), I added a placement new of the inner type to make sure we comply with the standard by explicitly starting the lifetime of the `Ptr` object in the storage. This allows me to `reinterpret_cast` this storage as `Ptr` in `getPointerAddress`.

I also added static asserts that the inner type is trivially copy constructible, move constructible and destructible, that gives me guarantees that the compiler generated the destructor and copy/move constructors of `PunnedPointer` are correct.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124571/new/

https://reviews.llvm.org/D124571

Files:
  llvm/include/llvm/ADT/PointerIntPair.h
  llvm/unittests/ADT/PointerIntPairTest.cpp

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