[PATCH] D81678: Introduce noundef attribute at call sites for stricter poison analysis

[Gui Andrade via Phabricator via cfe-commits]

guiand updated this revision to Diff 279949.
guiand added a comment.

Adds additional constraints on `noundef`: Not a `nullptr_t`, not a member pointer, and not coerced to a type of larger size. Disabled emitting in return position for non-C++ languages (or inside extern "C").

@rsmith, I just didn't address your comment about being conservative with black-holeing C++ functions returning undef. At least for msan purposes this shouldn't be a *too* much of a problem, but of course this attribute is for general use by LLVM passes. I'm just wondering what kind of tradeoff we want to make here, I suppose.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D81678/new/

https://reviews.llvm.org/D81678

Files:
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Driver/Options.td
  clang/lib/CodeGen/CGCall.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGen/indirect-noundef.cpp

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