DR1213: element access on an array xvalue or prvalue produces an xvalue. In the

latter case, a temporary array object is materialized, and can be
lifetime-extended by binding a reference to the member access. Likewise, in an
array-to-pointer decay, an rvalue array is materialized before being converted
into a pointer.

This caused IR generation to stop treating file-scope array compound literals
as having static storage duration in some cases in C++; that has been rectified
by modeling such a compound literal as an lvalue. This also improves clang's
compatibility with GCC for those cases.

llvm-svn: 288654

1 files changed, 3 insertions, 3 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index e212928..14214bd 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -2907,7 +2907,6 @@ static bool handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv,
       // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the
       // initializer until now for such expressions. Such an expression can't be
       // an ICE in C, so this only matters for fold.
-      assert(!Info.getLangOpts().CPlusPlus && "lvalue compound literal in c++?");
       if (Type.isVolatileQualified()) {
         Info.FFDiag(Conv);
         return false;
@@ -4711,7 +4710,7 @@ public:
 //  * VarDecl
 //  * FunctionDecl
 // - Literals
-//  * CompoundLiteralExpr in C
+//  * CompoundLiteralExpr in C (and in global scope in C++)
 //  * StringLiteral
 //  * CXXTypeidExpr
 //  * PredefinedExpr
@@ -4906,7 +4905,8 @@ bool LValueExprEvaluator::VisitMaterializeTemporaryExpr(
 
 bool
 LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
-  assert(!Info.getLangOpts().CPlusPlus && "lvalue compound literal in c++?");
+  assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) &&
+         "lvalue compound literal in c++?");
   // Defer visiting the literal until the lvalue-to-rvalue conversion. We can
   // only see this when folding in C, so there's no standard to follow here.
   return Success(E);