If a global variable has a specified alignment that is less than the preferred
alignment for its type, use the minimum of the specified alignment and the ABI
alignment. This fixes <rdar://problem/9275290>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129428 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index c628df0..d15855c 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -617,8 +617,12 @@
 unsigned TargetData::getPreferredAlignment(const GlobalVariable *GV) const {
   const Type *ElemType = GV->getType()->getElementType();
   unsigned Alignment = getPrefTypeAlignment(ElemType);
-  if (GV->getAlignment() > Alignment)
-    Alignment = GV->getAlignment();
+  unsigned GVAlignment = GV->getAlignment();
+  if (GVAlignment >= Alignment) {
+    Alignment = GVAlignment;
+  } else if (GVAlignment != 0) {
+    Alignment = std::min(GVAlignment, getABITypeAlignment(ElemType));
+  }
 
   if (GV->hasInitializer()) {
     if (Alignment < 16) {