[clang] [KeyInstr][Clang] Copy ctor/assignment operator source atoms (PR #144346)

[Jeremy Morse via cfe-commits]

https://github.com/jmorse commented:

>From the context, it feels like clang is going to try turning groups of initializers into memcpys, is that right? If so, does that affect the desired stepping behaviour, i.e. would multiple assignments be grouped into one memcpy? I suppose it's not majorly important (but worth having test coverage)

... ah that's what you've done, right. Leaving my comment for posterity. LGTM.

https://github.com/llvm/llvm-project/pull/144346