[PATCH] D101103: [InstSimplify] Treat invariant group insts as bitcasts for load operands

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added a comment.

looks like the strip is coming from `CodeGenFunction::EmitLValueForField()`:

  if (auto *ClassDef = dyn_cast<CXXRecordDecl>(rec)) {
    if (CGM.getCodeGenOpts().StrictVTablePointers &&
        ClassDef->isDynamicClass()) {
      // Getting to any field of dynamic object requires stripping dynamic
      // information provided by invariant.group.  This is because accessing
      // fields may leak the real address of dynamic object, which could result
      // in miscompilation when leaked pointer would be compared.
      auto *stripped = Builder.CreateStripInvariantGroup(addr.getPointer());
      addr = Address(stripped, addr.getAlignment());
    }
  }

is this actually true?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D101103/new/

https://reviews.llvm.org/D101103