From 0171c6b348815df326a063c7e78eb81b7347fa25 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Fri, 8 Nov 2013 22:59:46 +0000
Subject: [PATCH] If a linkonce_odr dtor/ctor is identical to another one, just
 rauw.

Unlike an alias a rauw is always safe, so we don't need to avoid this
optimization when the replacement is not know to be available in every TU.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194288 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGCXX.cpp               | 13 +++++++------
 test/CodeGenCXX/ctor-dtor-alias.cpp |  5 +++--
 test/CodeGenCXX/destructors.cpp     |  2 +-
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
index eeedaf1064..8c7a089460 100644
--- a/lib/CodeGen/CGCXX.cpp
+++ b/lib/CodeGen/CGCXX.cpp
@@ -139,6 +139,13 @@ bool CodeGenModule::TryEmitDefinitionAsAlias(GlobalDecl AliasDecl,
   if (Ref->getType() != AliasType)
     Aliasee = llvm::ConstantExpr::getBitCast(Ref, AliasType);
 
+  // Instead of creating as alias to a linkonce_odr, replace all of the uses
+  // of the aliassee.
+  if (Linkage == llvm::GlobalValue::LinkOnceODRLinkage) {
+    Replacements[MangledName] = Aliasee;
+    return false;
+  }
+
   // Don't create an alias to a linker weak symbol unless we know we can do
   // that in every TU. This avoids producing different COMDATs in different
   // TUs.
@@ -146,12 +153,6 @@ bool CodeGenModule::TryEmitDefinitionAsAlias(GlobalDecl AliasDecl,
     if (!InEveryTU)
       return true;
 
-    // Instead of creating as alias to a linkonce_odr, replace all of the uses
-    // of the aliassee.
-    if (Linkage == llvm::GlobalValue::LinkOnceODRLinkage) {
-      Replacements[MangledName] = Aliasee;
-      return false;
-    }
     assert(Linkage == TargetLinkage);
   }
 
diff --git a/test/CodeGenCXX/ctor-dtor-alias.cpp b/test/CodeGenCXX/ctor-dtor-alias.cpp
index ff9bd7c5c5..fdd378bab3 100644
--- a/test/CodeGenCXX/ctor-dtor-alias.cpp
+++ b/test/CodeGenCXX/ctor-dtor-alias.cpp
@@ -45,10 +45,11 @@ B x;
 
 namespace test4 {
   // Test that we don't produce aliases from B to A. We cannot because we cannot
-  // guarantee that they will be present in every TU.
+  // guarantee that they will be present in every TU. Instead, we just call
+  // A's destructor directly.
 
-  // CHECK-DAG: define linkonce_odr void @_ZN5test41BD2Ev(
   // CHECK-DAG: define linkonce_odr void @_ZN5test41AD2Ev(
+  // CHECK-DAG: call i32 @__cxa_atexit{{.*}}_ZN5test41AD2Ev
   struct A {
     virtual ~A() {}
   };
diff --git a/test/CodeGenCXX/destructors.cpp b/test/CodeGenCXX/destructors.cpp
index 887b73fcc5..b98c5c7e62 100644
--- a/test/CodeGenCXX/destructors.cpp
+++ b/test/CodeGenCXX/destructors.cpp
@@ -45,7 +45,7 @@ namespace PR7526 {
   allocator::~allocator() throw() { foo(); }
 
   // CHECK-LABEL: define void @_ZN6PR75263fooEv()
-  // CHECK: call void @_ZN6PR752617allocator_derivedD2Ev
+  // CHECK: call void {{.*}} @_ZN6PR75269allocatorD2Ev
 
   void foo() {
     allocator_derived ad;
-- 
2.40.0