Index: clang/lib/Basic/TargetInfo.cpp
===================================================================
--- clang/lib/Basic/TargetInfo.cpp
+++ clang/lib/Basic/TargetInfo.cpp
@@ -528,8 +528,6 @@
     // Apply the feature via the target.
     if (Name[0] != '+' && Name[0] != '-')
       Diags.Report(diag::warn_fe_backend_invalid_feature_flag) << Name;
-    else if (isReadOnlyFeature(Name.substr(1)))
-      Diags.Report(diag::warn_fe_backend_readonly_feature_flag) << Name;
     else
       setFeatureEnabled(Features, Name.substr(1), Name[0] == '+');
   }
Index: clang/lib/Basic/Targets.cpp
===================================================================
--- clang/lib/Basic/Targets.cpp
+++ clang/lib/Basic/Targets.cpp
@@ -42,6 +42,7 @@
 #include "Targets/X86.h"
 #include "Targets/XCore.h"
 #include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticFrontend.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/TargetParser/Triple.h"
 
@@ -816,6 +817,13 @@
 
   // Compute the default target features, we need the target to handle this
   // because features may have dependencies on one another.
+  llvm::erase_if(Opts->FeaturesAsWritten, [&](StringRef Name) {
+    if (Target->isReadOnlyFeature(Name.substr(1))) {
+      Diags.Report(diag::warn_fe_backend_readonly_feature_flag) << Name;
+      return true;
+    }
+    return false;
+  });
   if (!Target->initFeatureMap(Opts->FeatureMap, Diags, Opts->CPU,
                               Opts->FeaturesAsWritten))
     return nullptr;
Index: clang/test/OpenMP/driver-openmp-amdgpu.c
===================================================================
--- /dev/null
+++ clang/test/OpenMP/driver-openmp-amdgpu.c
@@ -0,0 +1,8 @@
+// REQUIRES: x86-registered-target
+// REQUIRES: amdgpu-registered-target
+// REQUIRES: clang-target-64-bits
+
+// Check no warnings about read-only feature emitted.
+// RUN: %clang %s -emit-llvm -S -fopenmp=libomp -nogpulib --offload-arch=gfx1030 \
+// RUN:   --offload-device-only -o - 2>&1 | FileCheck --check-prefix=CHECK %s
+// CHECK-NOT: warning: feature flag {{.*}} is ignored since the feature is read only