From 4020f8703a8822fe0d4efe4a0dc74f0b8040bd9f Mon Sep 17 00:00:00 2001
From: Fariborz Jahanian <fjahanian@apple.com>
Date: Tue, 24 Aug 2010 22:21:48 +0000
Subject: [PATCH] It is not error in c++ to take address of register variable
 (c++03 7.1.1P3). radar 8108252.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@111977 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaExpr.cpp                    | 5 ++++-
 test/SemaCXX/address-of-register-var.cpp | 9 +++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 test/SemaCXX/address-of-register-var.cpp

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index bd76b9ff12..6acef58f2c 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -6278,7 +6278,10 @@ QualType Sema::CheckAddressOfOperand(Expr *op, SourceLocation OpLoc) {
     // We have an lvalue with a decl. Make sure the decl is not declared
     // with the register storage-class specifier.
     if (const VarDecl *vd = dyn_cast<VarDecl>(dcl)) {
-      if (vd->getStorageClass() == VarDecl::Register) {
+      // in C++ it is not error to take address of a register
+      // variable (c++03 7.1.1P3)
+      if (vd->getStorageClass() == VarDecl::Register &&
+          !getLangOptions().CPlusPlus) {
         Diag(OpLoc, diag::err_typecheck_address_of)
           << "register variable" << op->getSourceRange();
         return QualType();
diff --git a/test/SemaCXX/address-of-register-var.cpp b/test/SemaCXX/address-of-register-var.cpp
new file mode 100644
index 0000000000..5d391c5a35
--- /dev/null
+++ b/test/SemaCXX/address-of-register-var.cpp
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// rdar // 8018252
+
+void f0() {
+  extern void f0_1(int*);
+  register int x;
+  f0_1(&x);
+}
+
-- 
2.50.1