From f8b3015060096a946d91578d0f3b65d3097a4ebb Mon Sep 17 00:00:00 2001
From: Anders Carlsson <andersca@mac.com>
Date: Sun, 28 Nov 2010 16:40:49 +0000
Subject: [PATCH] Look through parentheses when deciding whether an expr is a
 temporary object. Fixes PR8683.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@120247 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/AST/Expr.cpp                            |  8 ++++----
 test/CodeGenCXX/copy-constructor-elim-2.cpp | 22 +++++++++++++++++++++
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 3e3792e21f..3a112a7e07 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1804,7 +1804,7 @@ bool Expr::isDefaultArgument() const {
 
 /// \brief Skip over any no-op casts and any temporary-binding
 /// expressions.
-static const Expr *skipTemporaryBindingsAndNoOpCasts(const Expr *E) {
+static const Expr *skipTemporaryBindingsNoOpCastsAndParens(const Expr *E) {
   while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
     if (ICE->getCastKind() == CK_NoOp)
       E = ICE->getSubExpr();
@@ -1821,8 +1821,8 @@ static const Expr *skipTemporaryBindingsAndNoOpCasts(const Expr *E) {
     else
       break;
   }
-  
-  return E;
+
+  return E->IgnoreParens();
 }
 
 /// isTemporaryObject - Determines if this expression produces a
@@ -1831,7 +1831,7 @@ bool Expr::isTemporaryObject(ASTContext &C, const CXXRecordDecl *TempTy) const {
   if (!C.hasSameUnqualifiedType(getType(), C.getTypeDeclType(TempTy)))
     return false;
 
-  const Expr *E = skipTemporaryBindingsAndNoOpCasts(this);
+  const Expr *E = skipTemporaryBindingsNoOpCastsAndParens(this);
 
   // Temporaries are by definition pr-values of class type.
   if (!E->Classify(C).isPRValue()) {
diff --git a/test/CodeGenCXX/copy-constructor-elim-2.cpp b/test/CodeGenCXX/copy-constructor-elim-2.cpp
index 73e9b94bcd..563676f6e3 100644
--- a/test/CodeGenCXX/copy-constructor-elim-2.cpp
+++ b/test/CodeGenCXX/copy-constructor-elim-2.cpp
@@ -31,3 +31,25 @@ namespace no_elide_base {
     // CHECK: ret void
   }
 }
+
+// PR8683.
+
+namespace PR8683 {
+
+struct A {
+  A();
+  A(const A&);
+  A& operator=(const A&);
+};
+
+struct B {
+  A a;
+};
+
+void f() {
+  // Verify that we don't mark the copy constructor in this expression as elidable.
+  // CHECK: call void @_ZN6PR86831AC1ERKS0_
+  A a = (B().a);
+}
+
+}
-- 
2.40.0