Recognize when the named return value optimization applies in a

"return" statement and mark the corresponding CXXConstructExpr as
elidable. Teach CodeGen that eliding a temporary is different from
eliding an object construction.

This is just a baby step toward NRVO.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@103849 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 15c21008be..48daf84d6b 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -441,8 +441,10 @@ bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *&E) {
 
   // Initialize the exception result.  This implicitly weeds out
   // abstract types or types with inaccessible copy constructors.
+  // FIXME: Determine whether we can elide this copy per C++0x [class.copy]p34.
   InitializedEntity Entity =
-    InitializedEntity::InitializeException(ThrowLoc, E->getType());
+    InitializedEntity::InitializeException(ThrowLoc, E->getType(),
+                                           /*NRVO=*/false);
   OwningExprResult Res = PerformCopyInitialization(Entity,
                                                    SourceLocation(),
                                                    Owned(E));