Fix a bug with binding l-values to elided temporaries, and leave a couple

helpful asserts behind.

llvm-svn: 114250

2 files changed, 12 insertions, 6 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 9c1a3cf249a..924ca3ec4bb 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -1964,6 +1964,8 @@ LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
 }
 
 LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
+  assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
+         && "binding l-value to type which needs a temporary");
   AggValueSlot Slot = CreateAggTemp(E->getType(), "tmp");
   EmitCXXConstructExpr(E, Slot);
   return MakeAddrLValue(Slot.getAddr(), E->getType());
@@ -1976,9 +1978,11 @@ CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
 
 LValue
 CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
-  LValue LV = EmitLValue(E->getSubExpr());
-  EmitCXXTemporary(E->getTemporary(), LV.getAddress());
-  return LV;
+  AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
+  Slot.setLifetimeExternallyManaged();
+  EmitAggExpr(E->getSubExpr(), Slot);
+  EmitCXXTemporary(E->getTemporary(), Slot.getAddr());
+  return MakeAddrLValue(Slot.getAddr(), E->getType());
 }
 
 LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 4dbfa7ee4fa..aadceff8be5 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -280,10 +280,12 @@ CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
   if (CD->isTrivial() && CD->isDefaultConstructor())
     return;
   
-  // Code gen optimization to eliminate copy constructor and return
-  // its first argument instead, if in fact that argument is a temporary 
-  // object.
+  // Elide the constructor if we're constructing from a temporary.
+  // The temporary check is required because Sema sets this on NRVO
+  // returns.
   if (getContext().getLangOptions().ElideConstructors && E->isElidable()) {
+    assert(getContext().hasSameUnqualifiedType(E->getType(),
+                                               E->getArg(0)->getType()));
     if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) {
       EmitAggExpr(E->getArg(0), Dest);
       return;