From c96d4963eb2eb99f9fac36687194489ecfac7b9c Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Sat, 15 Aug 2009 21:55:26 +0000
Subject: Implement __is_empty.  Patch by Sean Hunt.

llvm-svn: 79143
---
 clang/lib/AST/ExprCXX.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'clang/lib/AST/ExprCXX.cpp')

diff --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index 454dc14b6c8..006f69890ab 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -223,6 +223,12 @@ bool UnaryTypeTraitExpr::EvaluateTrait(ASTContext& C) const {
     if (const RecordType *RT = QueriedType->getAs<RecordType>())
       return cast<CXXRecordDecl>(RT->getDecl())->isAbstract();
     return false;
+  case UTT_IsEmpty:
+    if (const RecordType *Record = QueriedType->getAs<RecordType>()) {
+      return !Record->getDecl()->isUnion()
+          && cast<CXXRecordDecl>(Record->getDecl())->isEmpty();
+    }
+    return false;
   case UTT_HasTrivialConstructor:
     // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
     //   If __is_pod (type) is true then the trait is true, else if type is
-- 
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