C++ PATCH: fix PR 10891

[Eric Botcazou]

> I also almost always add PR references when I fix optimizer bugs.  But
> what I do is first explain (in usually pretty lengthy comments) what the
> old code was not doing right and what the fix was, and _then_ refer to
> the PR for further details and an example of what went wrong.

The PR is alreay supposed to be referenced in the ChangeLog entry though.

-- 
Eric Botcazou