Index: lib/AST/ASTContext.cpp
===================================================================
--- lib/AST/ASTContext.cpp
+++ lib/AST/ASTContext.cpp
@@ -1600,8 +1600,25 @@
       if (BaseT.getQualifiers().hasUnaligned())
         Align = Target->getCharWidth();
       if (const auto *VD = dyn_cast<VarDecl>(D)) {
-        if (VD->hasGlobalStorage() && !ForAlignof)
+        if (VD->hasGlobalStorage() && !ForAlignof) {
           Align = std::max(Align, getTargetInfo().getMinGlobalAlign());
+
+          // MSVC does size based alignment for arm64 based on alignment section
+          // in below document, replicate that to keep alignment consistent with
+          // object files compiled by MSVC.
+          // https://docs.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions
+          if (getTargetInfo().getTriple().getArch() == llvm::Triple::aarch64 &&
+              getTargetInfo().getTriple().getEnvironment() == llvm::Triple::MSVC) {
+            uint64_t TypeSize = getTypeSize(T.getTypePtr());
+            if (TypeSize >= 512) {              // TypeSize >= 64 bytes
+              Align = std::max(Align, 128u);    // align type at least 16 bytes
+            } else if (TypeSize >= 64) {        // TypeSize >= 8 bytes
+              Align = std::max(Align, 64u);     // align type at least 8 butes
+            } else if (TypeSize >= 16) {        // TypeSize >= 2 bytes
+              Align = std::max(Align, 32u);     // align type at least 4 bytes
+            }
+          }
+        }
       }
     }