diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index feed2b48afc2..64259b3e9935 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2626,6 +2626,7 @@ llvm::DIType CGDebugInfo::EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
   llvm::DIType FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
   FieldSize = CGM.getContext().getTypeSize(FType);
   FieldAlign = CGM.getContext().toBits(Align);
+  FieldOffset += FieldOffset % FieldAlign;
 
   *XOffset = FieldOffset;
   FieldTy = DBuilder.createMemberType(Unit, VD->getName(), Unit,
diff --git a/clang/test/CodeGenObjC/block-byref-debuginfo.m b/clang/test/CodeGenObjC/block-byref-debuginfo.m
new file mode 100644
index 000000000000..f918d32a988a
--- /dev/null
+++ b/clang/test/CodeGenObjC/block-byref-debuginfo.m
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -fblocks -fobjc-arc -fobjc-runtime-has-weak -g -triple x86_64-apple-darwin -O0 -emit-llvm %s -o - | FileCheck %s
+
+// Test that the foo is aligned at an 8 byte boundary in the DWARF
+// expression (256) that locates it inside of the byref descriptor:
+// CHECK: metadata !"foo", i32 0, i64 {{[0-9]+}}, i64 64, i64 256, i32 0, metadata
+
+typedef unsigned char uint8_t;
+@protocol NSObject
+@end
+@interface NSObject <NSObject> {
+}
+@end
+typedef void (^dispatch_block_t)(void);
+typedef long dispatch_once_t;
+static __inline__ __attribute__((__always_inline__)) __attribute__((__nonnull__)) __attribute__((__nothrow__))
+void
+_dispatch_once(dispatch_once_t *predicate, dispatch_block_t block)
+{
+};
+typedef struct Buffer *BufferRef;
+typedef struct Foo_s {
+    uint8_t *data;
+} Foo;
+@protocol DelegateProtocol <NSObject>
+@end
+@interface FileReader : NSObject <DelegateProtocol>
+{
+ dispatch_once_t offset;
+}
+@end
+@implementation FileReader
+- (BufferRef) bar:(int *)index
+{
+  __attribute__((__blocks__(byref))) Foo foo;
+  _dispatch_once(&offset, ^{});
+  return 0;
+}
+@end