[Alignment][NFC] Remove dependency on GlobalObject::setAlignment(unsigned)

Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: arsenm, mehdi_amini, jvesely, nhaehnle, hiraditya, steven_wu, dexonsmith, dang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68944

llvm-svn: 374880
diff --git a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
index 4055fe0..e1578cc 100644
--- a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
+++ b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
@@ -1516,10 +1516,11 @@
 
   // Align the before byte array to the global's minimum alignment so that we
   // don't break any alignment requirements on the global.
-  unsigned Align = B.GV->getAlignment();
-  if (Align == 0)
-    Align = M.getDataLayout().getABITypeAlignment(B.GV->getValueType());
-  B.Before.Bytes.resize(alignTo(B.Before.Bytes.size(), Align));
+  MaybeAlign Alignment(B.GV->getAlignment());
+  if (!Alignment)
+    Alignment =
+        Align(M.getDataLayout().getABITypeAlignment(B.GV->getValueType()));
+  B.Before.Bytes.resize(alignTo(B.Before.Bytes.size(), Alignment));
 
   // Before was stored in reverse order; flip it now.
   for (size_t I = 0, Size = B.Before.Bytes.size(); I != Size / 2; ++I)
@@ -1536,7 +1537,7 @@
                          GlobalVariable::PrivateLinkage, NewInit, "", B.GV);
   NewGV->setSection(B.GV->getSection());
   NewGV->setComdat(B.GV->getComdat());
-  NewGV->setAlignment(B.GV->getAlignment());
+  NewGV->setAlignment(MaybeAlign(B.GV->getAlignment()));
 
   // Copy the original vtable's metadata to the anonymous global, adjusting
   // offsets as required.