Revert r360559 "[c++20] P1064R0: Allow virtual function calls in constant expression evaluation."

This caused Chromium builds to hit the new "can't handle virtual calls with
virtual bases" assert. Reduced repro coming up.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@360580 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 10 insertions, 41 deletions

diff --git a/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp b/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp
index cc3917093e..ffc408cddb 100644
--- a/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp
+++ b/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p3.cpp
@@ -20,10 +20,7 @@ struct Literal {
 };
 
 struct S {
-  virtual int ImplicitlyVirtual() const = 0;
-#if __cplusplus <= 201703L
-  // expected-note@-2 {{overridden virtual function}}
-#endif
+  virtual int ImplicitlyVirtual() const = 0; // expected-note {{overridden virtual function}}
 };
 struct SS : S {
   int ImplicitlyVirtual() const;
@@ -35,21 +32,12 @@ struct T : SS, NonLiteral {
   constexpr T();
   constexpr int f() const;
 
-  //  - it shall not be virtual; [until C++20]
-  virtual constexpr int ExplicitlyVirtual() const { return 0; }
-#if __cplusplus <= 201703L
-  // expected-error@-2 {{virtual function cannot be constexpr}}
-#endif
+  //  - it shall not be virtual;
+  virtual constexpr int ExplicitlyVirtual() const { return 0; } // expected-error {{virtual function cannot be constexpr}}
 
-  constexpr int ImplicitlyVirtual() const { return 0; }
-#if __cplusplus <= 201703L
-  // expected-error@-2 {{virtual function cannot be constexpr}}
-#endif
+  constexpr int ImplicitlyVirtual() const { return 0; } // expected-error {{virtual function cannot be constexpr}}
 
-  virtual constexpr int OutOfLineVirtual() const;
-#if __cplusplus <= 201703L
-  // expected-error@-2 {{virtual function cannot be constexpr}}
-#endif
+  virtual constexpr int OutOfLineVirtual() const; // expected-error {{virtual function cannot be constexpr}}
 
   //  - its return type shall be a literal type;
   constexpr NonLiteral NonLiteralReturn() const { return {}; } // expected-error {{constexpr function's return type 'NonLiteral' is not a literal type}}
diff --git a/test/CXX/drs/dr18xx.cpp b/test/CXX/drs/dr18xx.cpp
index 33c0452b6c..5df132c368 100644
--- a/test/CXX/drs/dr18xx.cpp
+++ b/test/CXX/drs/dr18xx.cpp
@@ -52,19 +52,9 @@ namespace dr1872 { // dr1872: 9
   struct Z : virtual X {};
 
   constexpr int x = A<X>().f();
-  constexpr int y = A<Y>().f();
-#if __cplusplus <= 201703L
-  // expected-error@-2 {{constant expression}} expected-note@-2 {{call to virtual function}}
-#else
-  static_assert(y == 0);
-#endif
+  constexpr int y = A<Y>().f(); // expected-error {{constant expression}} expected-note {{call to virtual function}}
   // Note, this is invalid even though it would not use virtual dispatch.
-  constexpr int y2 = A<Y>().A<Y>::f();
-#if __cplusplus <= 201703L
-  // expected-error@-2 {{constant expression}} expected-note@-2 {{call to virtual function}}
-#else
-  static_assert(y == 0);
-#endif
+  constexpr int y2 = A<Y>().A<Y>::f(); // expected-error {{constant expression}} expected-note {{call to virtual function}}
   constexpr int z = A<Z>().f(); // expected-error {{constant expression}} expected-note {{non-literal type}}
 #endif
 }
diff --git a/test/CXX/drs/dr6xx.cpp b/test/CXX/drs/dr6xx.cpp
index 31642dfbb0..318096c299 100644
--- a/test/CXX/drs/dr6xx.cpp
+++ b/test/CXX/drs/dr6xx.cpp
@@ -479,21 +479,12 @@ namespace dr647 { // dr647: yes
   // This is partially superseded by dr1358.
   struct A {
     constexpr virtual void f() const;
-    constexpr virtual void g() const {}
-#if __cplusplus <= 201703L
-    // expected-error@-2 {{virtual function cannot be constexpr}}
-#endif
+    constexpr virtual void g() const {} // expected-error {{virtual function cannot be constexpr}}
   };
 
-  struct X { virtual void f() const; };
-#if __cplusplus <= 201703L
-  // expected-note@-2 {{overridden}}
-#endif
+  struct X { virtual void f() const; }; // expected-note {{overridden}}
   struct B : X {
-    constexpr void f() const {}
-#if __cplusplus <= 201703L
-    // expected-error@-2 {{virtual function cannot be constexpr}}
-#endif
+    constexpr void f() const {} // expected-error {{virtual function cannot be constexpr}}
   };
 
   struct NonLiteral { NonLiteral() {} }; // expected-note {{not an aggregate and has no constexpr constructors}}