diff --git a/lib/CodeGen/CGBlocks.cpp b/lib/CodeGen/CGBlocks.cpp
index 15347a4..2c32c42 100644
--- a/lib/CodeGen/CGBlocks.cpp
+++ b/lib/CodeGen/CGBlocks.cpp
@@ -176,7 +176,7 @@
     // block literal.
     // __invoke
     CharUnits subBlockSize; 
-    uint64_t subBlockAlign;
+    CharUnits subBlockAlign;
     llvm::SmallVector<const Expr *, 8> subBlockDeclRefDecls;
     bool subBlockHasCopyDispose = false;
     llvm::Function *Fn
@@ -249,7 +249,7 @@
     llvm::StructType *Ty = llvm::StructType::get(VMContext, Types, true);
 
     llvm::AllocaInst *A = CreateTempAlloca(Ty);
-    A->setAlignment(subBlockAlign);
+    A->setAlignment(subBlockAlign.getQuantity());
     V = A;
 
     std::vector<HelperInfo> NoteForHelper(subBlockDeclRefDecls.size());
@@ -615,7 +615,7 @@
 
   CodeGenFunction::BlockInfo Info(0, n);
   CharUnits subBlockSize; 
-  uint64_t subBlockAlign;
+  CharUnits subBlockAlign;
   llvm::SmallVector<const Expr *, 8> subBlockDeclRefDecls;
   bool subBlockHasCopyDispose = false;
   llvm::DenseMap<const Decl*, llvm::Value*> LocalDeclMap;
@@ -678,7 +678,7 @@
                                        const Decl *OuterFuncDecl,
                                   llvm::DenseMap<const Decl*, llvm::Value*> ldm,
                                        CharUnits &Size,
-                                       uint64_t &Align,
+                                       CharUnits &Align,
                        llvm::SmallVector<const Expr *, 8> &subBlockDeclRefDecls,
                                        bool &subBlockHasCopyDispose) {
 
@@ -700,7 +700,7 @@
 
   BlockOffset = 
       CGM.GetTargetTypeStoreSize(CGM.getGenericBlockLiteralType());
-  BlockAlign = getContext().getTypeAlign(getContext().VoidPtrTy) / 8;
+  BlockAlign = getContext().getTypeAlignInChars(getContext().VoidPtrTy);
 
   const FunctionType *BlockFunctionType = BExpr->getFunctionType();
   QualType ResultType;
@@ -796,9 +796,10 @@
   FinishFunction(cast<CompoundStmt>(BExpr->getBody())->getRBracLoc());
 
   // The runtime needs a minimum alignment of a void *.
-  uint64_t MinAlign = getContext().getTypeAlign(getContext().VoidPtrTy) / 8;
+  CharUnits MinAlign = getContext().getTypeAlignInChars(getContext().VoidPtrTy);
   BlockOffset = CharUnits::fromQuantity(
-      llvm::RoundUpToAlignment(BlockOffset.getQuantity(), MinAlign));
+      llvm::RoundUpToAlignment(BlockOffset.getQuantity(), 
+                               MinAlign.getQuantity()));
 
   Size = BlockOffset;
   Align = BlockAlign;
@@ -811,20 +812,21 @@
   const ValueDecl *D = dyn_cast<ValueDecl>(BDRE->getDecl());
 
   CharUnits Size = getContext().getTypeSizeInChars(D->getType());
-  uint64_t Align = getContext().getDeclAlignInBytes(D);
+  CharUnits Align = 
+    CharUnits::fromQuantity(getContext().getDeclAlignInBytes(D));
 
   if (BDRE->isByRef()) {
     Size = getContext().getTypeSizeInChars(getContext().VoidPtrTy);
-    Align = getContext().getTypeAlign(getContext().VoidPtrTy) / 8;
+    Align = getContext().getTypeAlignInChars(getContext().VoidPtrTy);
   }
 
-  assert ((Align > 0) && "alignment must be 1 byte or more");
+  assert ((Align.isPositive()) && "alignment must be 1 byte or more");
 
   CharUnits OldOffset = BlockOffset;
 
   // Ensure proper alignment, even if it means we have to have a gap
   BlockOffset = CharUnits::fromQuantity(
-      llvm::RoundUpToAlignment(BlockOffset.getQuantity(), Align));
+      llvm::RoundUpToAlignment(BlockOffset.getQuantity(), Align.getQuantity()));
   BlockAlign = std::max(Align, BlockAlign);
 
   CharUnits Pad = BlockOffset - OldOffset;
diff --git a/lib/CodeGen/CGBlocks.h b/lib/CodeGen/CGBlocks.h
index f42244c..a9f5ae0 100644
--- a/lib/CodeGen/CGBlocks.h
+++ b/lib/CodeGen/CGBlocks.h
@@ -177,8 +177,9 @@
   /// BlockOffset - The offset in bytes for the next allocation of an
   /// imported block variable.
   CharUnits BlockOffset;
-  /// BlockAlign - Maximal alignment needed for the Block expressed in bytes.
-  uint64_t BlockAlign;
+  /// BlockAlign - Maximal alignment needed for the Block expressed in 
+  /// characters.
+  CharUnits BlockAlign;
 
   /// getBlockOffset - Allocate an offset for the ValueDecl from a
   /// BlockDeclRefExpr in a block literal (BlockExpr).
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 684d1ce..f1b213d 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -475,7 +475,7 @@
                                         const BlockInfo& Info,
                                         const Decl *OuterFuncDecl,
                                   llvm::DenseMap<const Decl*, llvm::Value*> ldm,
-                                        CharUnits &Size, uint64_t &Align,
+                                        CharUnits &Size, CharUnits &Align,
                       llvm::SmallVector<const Expr *, 8> &subBlockDeclRefDecls,
                                         bool &subBlockHasCopyDispose);