[PATCH] D47103: Implement strip.invariant.group

[John McCall via Phabricator via cfe-commits]

rjmccall added inline comments.


================
Comment at: clang/lib/CodeGen/CGExpr.cpp:3858
+    }
+  }
+
----------------
Prazek wrote:
> rjmccall wrote:
> > Please add a comment explaining why this is necessary.  (I'm actually not sure why it is, because surely the invariant groups we generate don't contain assumptions about memory from fields, right?)
> Short answer: you can only make virtual calls on a dynamic pointer that carries invariant.group and you can't do anything other because it could leak the information about this pointer (which when used with comparison could break devirtualization). 
Alright, sure.


Repository:
  rL LLVM

https://reviews.llvm.org/D47103