diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 3e45cd8cbb0..82c186e1c3f 100644
--- a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -479,18 +479,10 @@ void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
   IsFunctionEHFrameSymbolPrivate = false;
   SupportsWeakOmittedEHFrame = false;
 
+  // .comm doesn't support alignment before Leopard.
   Triple T(((LLVMTargetMachine&)TM).getTargetTriple());
-  if (T.getOS() == Triple::Darwin) {
-    switch (T.getDarwinMajorNumber()) {
-    case 7:  // 10.3 Panther.
-    case 8:  // 10.4 Tiger.
-      CommDirectiveSupportsAlignment = false;
-      break;
-    case 9:   // 10.5 Leopard.
-    case 10:  // 10.6 SnowLeopard.
-      break;
-    }
-  }
+  if (T.isOSX() && T.isOSXVersionLT(10, 5))
+    CommDirectiveSupportsAlignment = false;
 
   TargetLoweringObjectFile::Initialize(Ctx, TM);
 
diff --git a/test/CodeGen/ARM/align.ll b/test/CodeGen/ARM/align.ll
index d57c159b85c..9589e72df2f 100644
--- a/test/CodeGen/ARM/align.ll
+++ b/test/CodeGen/ARM/align.ll
@@ -1,5 +1,5 @@
 ; RUN: llc < %s -mtriple=arm-linux-gnueabi | FileCheck %s -check-prefix=ELF
-; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s -check-prefix=DARWIN
+; RUN: llc < %s -mtriple=arm-apple-darwin10 | FileCheck %s -check-prefix=DARWIN
 
 @a = global i1 true
 ; no alignment