[PATCH RFA] cgraph: flatten and same_body aliases [PR96078]

[Jeff Law]

On 2/11/21 10:18 PM, Jason Merrill via Gcc-patches wrote:
> The patch for PR92372 made us start warning about a flatten attribute on an
> alias.  But in the case of C++ 'tor base/complete variants, the user didn't
> create the alias, so we shouldn't warn.
>
> I could also remove the attribute in maybe_clone_body, but here seems a bit
> better.
>
> Tested x86_64-pc-linux-gnu.  OK for trunk?
>
> gcc/ChangeLog:
>
> 	PR c++/96078
> 	* cgraph.c (cgraph_node::create_same_body_alias): Remove flatten
> 	attribute from alias.
>
> gcc/testsuite/ChangeLog:
>
> 	PR c++/96078
> 	* g++.dg/ext/attr-flatten1.C: New test.
But shouldn't we validate that we've got a C++ ctor/dtor rather than
blindly removing the attribute from all aliases?  ISTM like the patch
as-is would always suppress warnings when we create a same-body alias
regardless of why we created a same-body alias.

jeff