[c++17] P0135R1: Guaranteed copy elision.

When an object of class type is initialized from a prvalue of the same type
(ignoring cv qualifications), use the prvalue to initialize the object directly
instead of inserting a redundant elidable call to a copy constructor.

llvm-svn: 288866

1 files changed, 6 insertions, 1 deletions

diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index 763a0679562..895ac2b60ca 100644
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -3786,7 +3786,7 @@ public:
 
   /// \brief Build an empty initializer list.
   explicit InitListExpr(EmptyShell Empty)
-    : Expr(InitListExprClass, Empty) { }
+    : Expr(InitListExprClass, Empty), AltForm(nullptr, true) { }
 
   unsigned getNumInits() const { return InitExprs.size(); }
 
@@ -3894,6 +3894,11 @@ public:
   // literal or an @encode?
   bool isStringLiteralInit() const;
 
+  /// Is this a transparent initializer list (that is, an InitListExpr that is
+  /// purely syntactic, and whose semantics are that of the sole contained
+  /// initializer)?
+  bool isTransparent() const;
+
   SourceLocation getLBraceLoc() const { return LBraceLoc; }
   void setLBraceLoc(SourceLocation Loc) { LBraceLoc = Loc; }
   SourceLocation getRBraceLoc() const { return RBraceLoc; }