diff --git a/clang/lib/Basic/Targets/AArch64.cpp b/clang/lib/Basic/Targets/AArch64.cpp
index 0de8727a1a37..2a85c89cbb38 100644
--- a/clang/lib/Basic/Targets/AArch64.cpp
+++ b/clang/lib/Basic/Targets/AArch64.cpp
@@ -452,6 +452,8 @@ WindowsARM64TargetInfo::checkCallingConvention(CallingConv CC) const {
     return CCCR_Ignore;
   case CC_C:
   case CC_OpenCLKernel:
+  case CC_PreserveMost:
+  case CC_PreserveAll:
   case CC_Win64:
     return CCCR_OK;
   default:
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index a08eeec59dcb..27732dbe3bcd 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -916,6 +916,8 @@ public:
     case CC_C:
     case CC_X86VectorCall:
     case CC_IntelOclBicc:
+    case CC_PreserveMost:
+    case CC_PreserveAll:
     case CC_X86_64SysV:
     case CC_Swift:
     case CC_X86RegCall:
diff --git a/clang/test/CodeGen/preserve-call-conv.c b/clang/test/CodeGen/preserve-call-conv.c
index 6e91a8489b40..b67e29f392a4 100644
--- a/clang/test/CodeGen/preserve-call-conv.c
+++ b/clang/test/CodeGen/preserve-call-conv.c
@@ -1,6 +1,9 @@
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm < %s | FileCheck %s
 // RUN: %clang_cc1 -triple arm64-unknown-unknown -emit-llvm < %s | FileCheck %s
 
+// RUN: %clang_cc1 -triple x86_64-unknown-windows-msvc -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple aarch64-unknown-windows-msvc -emit-llvm %s -o - | FileCheck %s
+
 // Check that the preserve_most calling convention attribute at the source level
 // is lowered to the corresponding calling convention attrribute at the LLVM IR
 // level.
diff --git a/clang/test/Sema/preserve-call-conv.c b/clang/test/Sema/preserve-call-conv.c
index f258f45ac582..6bd049ffdca2 100644
--- a/clang/test/Sema/preserve-call-conv.c
+++ b/clang/test/Sema/preserve-call-conv.c
@@ -1,5 +1,8 @@
 // RUN: %clang_cc1 %s -fsyntax-only -triple x86_64-unknown-unknown -verify
 // RUN: %clang_cc1 %s -fsyntax-only -triple arm64-unknown-unknown -verify
+// RUN: %clang_cc1 %s -fsyntax-only -triple x86_64-unknown-windows-msvc -verify
+// RUN: %clang_cc1 %s -fsyntax-only -triple aarch64-unknown-windows-msvc -verify
+
 typedef void typedef_fun_t(int);
 
 void __attribute__((preserve_most)) foo(void *ptr) {