Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -1799,6 +1799,29 @@
         D->getType().isConstant(Context) &&
         isExternallyVisible(D->getLinkageAndVisibility().getLinkage()))
       GV->setSection(".cp.rodata");
+
+    // The ARM/AArch64 ABI expects structs with bitfields to respect the proper
+    // container alignment, hence we have to enfore this in the IR so as to
+    // work around clang combining bitfields into one large type.
+    llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch();
+    if (   Arch == llvm::Triple::arm
+        || Arch == llvm::Triple::armeb
+        || Arch == llvm::Triple::thumb
+        || Arch == llvm::Triple::thumbeb
+        || Arch == llvm::Triple::aarch64
+        || Arch == llvm::Triple::aarch64_be) {
+      if (const auto *RT = D->getType()->getAs<RecordType>()) {
+        const RecordDecl *RD = RT->getDecl();
+
+        for (auto I = RD->field_begin(), End = RD->field_end(); I != End; ++I) {
+          if ((*I)->isBitField()) {
+            const ASTRecordLayout &Info = getContext().getASTRecordLayout(RD);
+            GV->setAlignment(Info.getAlignment().getQuantity());
+            break;
+          }
+        }
+      }
+    }
   }
 
   if (AddrSpace != Ty->getAddressSpace())