r360559 - [c++20] P1064R0: Allow virtual function calls in constant expression

[Hans Wennborg via cfe-commits]

This caused asserts in Chromium, so I've reverted in r360580. There's
a repro at https://bugs.chromium.org/p/chromium/issues/detail?id=962458#c1,
and I'm working on a reduced version.

From: Richard Smith via cfe-commits <cfe-commits at lists.llvm.org>
Date: Mon, May 13, 2019 at 9:39 AM
To: <cfe-commits at lists.llvm.org>

> Author: rsmith
> Date: Mon May 13 00:42:10 2019
> New Revision: 360559
>
> URL: http://llvm.org/viewvc/llvm-project?rev=360559&view=rev
> Log:
> [c++20] P1064R0: Allow virtual function calls in constant expression
> evaluation.
>
> Modified:
>     cfe/trunk/include/clang/AST/DeclCXX.h
>     cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
>     cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>     cfe/trunk/include/clang/Sema/Sema.h
>     cfe/trunk/lib/AST/DeclCXX.cpp
>     cfe/trunk/lib/AST/ExprConstant.cpp
>     cfe/trunk/lib/Sema/SemaDeclCXX.cpp
>     cfe/trunk/lib/Sema/SemaTemplateInstantiate.cpp
>     cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp
>     cfe/trunk/test/CXX/drs/dr18xx.cpp
>     cfe/trunk/test/CXX/drs/dr6xx.cpp
>     cfe/trunk/test/SemaCXX/constant-expression-cxx2a.cpp
>     cfe/trunk/test/SemaCXX/cxx17-compat.cpp
>     cfe/trunk/www/cxx_status.html