diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index a97182cad5d513..a4c5a76b59cb1b 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -8837,6 +8837,12 @@ def err_cuda_ovl_target : Error<
   "cannot overload %select{__device__|__global__|__host__|__host__ __device__}2 function %3">;
 def note_cuda_ovl_candidate_target_mismatch : Note<
     "candidate template ignored: target attributes do not match">;
+def warn_offload_incompatible_redeclare : Warning<
+  "incompatible host/device attribute with redeclaration: "
+  "new declaration is %select{__device__|__global__|__host__|__host__ __device__}0 function, "
+  "old declaration is %select{__device__|__global__|__host__|__host__ __device__}1 function. "
+  "It will cause warning with nvcc">,
+  InGroup<DiagGroup<"offload-incompatible-redeclare">>, DefaultIgnore;
 
 def err_cuda_device_builtin_surftex_cls_template : Error<
     "illegal device builtin %select{surface|texture}0 reference "
diff --git a/clang/lib/Sema/SemaCUDA.cpp b/clang/lib/Sema/SemaCUDA.cpp
index 6a66ecf6f94c17..27da1775d4751d 100644
--- a/clang/lib/Sema/SemaCUDA.cpp
+++ b/clang/lib/Sema/SemaCUDA.cpp
@@ -992,22 +992,29 @@ void Sema::checkCUDATargetOverload(FunctionDecl *NewFD,
     // HD/global functions "exist" in some sense on both the host and device, so
     // should have the same implementation on both sides.
     if (NewTarget != OldTarget &&
-        ((NewTarget == CFT_HostDevice &&
-          !(LangOpts.OffloadImplicitHostDeviceTemplates &&
-            isCUDAImplicitHostDeviceFunction(NewFD) &&
-            OldTarget == CFT_Device)) ||
-         (OldTarget == CFT_HostDevice &&
-          !(LangOpts.OffloadImplicitHostDeviceTemplates &&
-            isCUDAImplicitHostDeviceFunction(OldFD) &&
-            NewTarget == CFT_Device)) ||
-         (NewTarget == CFT_Global) || (OldTarget == CFT_Global)) &&
         !IsOverload(NewFD, OldFD, /* UseMemberUsingDeclRules = */ false,
                     /* ConsiderCudaAttrs = */ false)) {
-      Diag(NewFD->getLocation(), diag::err_cuda_ovl_target)
-          << NewTarget << NewFD->getDeclName() << OldTarget << OldFD;
-      Diag(OldFD->getLocation(), diag::note_previous_declaration);
-      NewFD->setInvalidDecl();
-      break;
+      if ((NewTarget == CFT_HostDevice &&
+           !(LangOpts.OffloadImplicitHostDeviceTemplates &&
+             isCUDAImplicitHostDeviceFunction(NewFD) &&
+             OldTarget == CFT_Device)) ||
+          (OldTarget == CFT_HostDevice &&
+           !(LangOpts.OffloadImplicitHostDeviceTemplates &&
+             isCUDAImplicitHostDeviceFunction(OldFD) &&
+             NewTarget == CFT_Device)) ||
+          (NewTarget == CFT_Global) || (OldTarget == CFT_Global)) {
+        Diag(NewFD->getLocation(), diag::err_cuda_ovl_target)
+            << NewTarget << NewFD->getDeclName() << OldTarget << OldFD;
+        Diag(OldFD->getLocation(), diag::note_previous_declaration);
+        NewFD->setInvalidDecl();
+        break;
+      }
+      if ((NewTarget == CFT_Host && OldTarget == CFT_Device) ||
+          (NewTarget == CFT_Device && OldTarget == CFT_Host)) {
+        Diag(NewFD->getLocation(), diag::warn_offload_incompatible_redeclare)
+            << NewTarget << OldTarget;
+        Diag(OldFD->getLocation(), diag::note_previous_declaration);
+      }
     }
   }
 }
diff --git a/clang/test/SemaCUDA/function-redclare.cu b/clang/test/SemaCUDA/function-redclare.cu
new file mode 100644
index 00000000000000..266483ebf49f0e
--- /dev/null
+++ b/clang/test/SemaCUDA/function-redclare.cu
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fsyntax-only \
+// RUN:   -isystem %S/Inputs -verify %s
+// RUN: %clang_cc1 -triple nvptx64-nvidia-cuda -fsyntax-only \
+// RUN:   -isystem %S/Inputs -fcuda-is-device -verify %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fsyntax-only \
+// RUN:   -isystem %S/Inputs -verify=redecl -Woffload-incompatible-redeclare %s
+// RUN: %clang_cc1 -triple nvptx64-nvidia-cuda -fsyntax-only \
+// RUN:   -isystem %S/Inputs -fcuda-is-device -Woffload-incompatible-redeclare -verify=redecl %s
+
+// expected-no-diagnostics
+#include "cuda.h"
+
+__device__ void f(); // redecl-note {{previous declaration is here}}
+
+void f() {} // redecl-warning {{incompatible host/device attribute with redeclaration: new declaration is __host__ function, old declaration is __device__ function. It will cause warning with nvcc}}
+
+void g(); // redecl-note {{previous declaration is here}}
+
+__device__ void g() {} // redecl-warning {{incompatible host/device attribute with redeclaration: new declaration is __device__ function, old declaration is __host__ function. It will cause warning with nvcc}}