[clang] [C2y] Implement WG14 N3369 and N3469 (_Countof) (PR #133125)

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git-clang-format --diff 15f5a7a3ec71c624cea0cbdf02e3c5205ba81d9d 75ef42d644da9136fb07014ade18b6be137426a1 --extensions c,cpp -- clang/test/C/C2y/n3369.c clang/test/C/C2y/n3369_1.c clang/test/C/C2y/n3369_2.c clang/test/C/C2y/n3469.c clang/lib/AST/ExprConstant.cpp clang/lib/AST/ItaniumMangle.cpp clang/lib/CodeGen/CGExprScalar.cpp clang/lib/Parse/ParseExpr.cpp clang/lib/Sema/SemaExpr.cpp
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View the diff from clang-format here.
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diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 92b1f41bf2..31589ec553 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -17442,7 +17442,7 @@ static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
   }
   case Expr::UnaryExprOrTypeTraitExprClass: {
     const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E);
-    if ((Exp->getKind() ==  UETT_SizeOf || Exp->getKind() == UETT_CountOf) &&
+    if ((Exp->getKind() == UETT_SizeOf || Exp->getKind() == UETT_CountOf) &&
         Exp->getTypeOfArgument()->isVariableArrayType())
       return ICEDiag(IK_NotICE, E->getBeginLoc());
     return NoDiag();
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 0a22f7372a..14c9b59926 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -953,20 +953,18 @@ ExprResult Parser::ParseBuiltinPtrauthTypeDiscriminator() {
 /// [OBJC]  '\@encode' '(' type-name ')'
 /// [OBJC]  objc-string-literal
 /// [C++]   simple-type-specifier '(' expression-list[opt] ')'      [C++ 5.2.3]
-/// [C++11] simple-type-specifier braced-init-list                  [C++11 5.2.3]
-/// [C++]   typename-specifier '(' expression-list[opt] ')'         [C++ 5.2.3]
-/// [C++11] typename-specifier braced-init-list                     [C++11 5.2.3]
-/// [C++]   'const_cast' '<' type-name '>' '(' expression ')'       [C++ 5.2p1]
-/// [C++]   'dynamic_cast' '<' type-name '>' '(' expression ')'     [C++ 5.2p1]
-/// [C++]   'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
-/// [C++]   'static_cast' '<' type-name '>' '(' expression ')'      [C++ 5.2p1]
-/// [C++]   'typeid' '(' expression ')'                             [C++ 5.2p1]
-/// [C++]   'typeid' '(' type-id ')'                                [C++ 5.2p1]
-/// [C++]   'this'          [C++ 9.3.2]
-/// [G++]   unary-type-trait '(' type-id ')'
-/// [G++]   binary-type-trait '(' type-id ',' type-id ')'           [TODO]
-/// [EMBT]  array-type-trait '(' type-id ',' integer ')'
-/// [clang] '^' block-literal
+/// [C++11] simple-type-specifier braced-init-list [C++11 5.2.3] [C++]
+/// typename-specifier '(' expression-list[opt] ')'         [C++ 5.2.3] [C++11]
+/// typename-specifier braced-init-list                     [C++11 5.2.3] [C++]
+/// 'const_cast' '<' type-name '>' '(' expression ')'       [C++ 5.2p1] [C++]
+/// 'dynamic_cast' '<' type-name '>' '(' expression ')'     [C++ 5.2p1] [C++]
+/// 'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1] [C++]
+/// 'static_cast' '<' type-name '>' '(' expression ')'      [C++ 5.2p1] [C++]
+/// 'typeid' '(' expression ')'                             [C++ 5.2p1] [C++]
+/// 'typeid' '(' type-id ')'                                [C++ 5.2p1] [C++]
+/// 'this'          [C++ 9.3.2] [G++]   unary-type-trait '(' type-id ')' [G++]
+/// binary-type-trait '(' type-id ',' type-id ')'           [TODO] [EMBT]
+/// array-type-trait '(' type-id ',' integer ')' [clang] '^' block-literal
 ///
 ///       constant: [C99 6.4.4]
 ///         integer-constant

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https://github.com/llvm/llvm-project/pull/133125