[flang][cuda] Remove meaningless warning on CUDA shared arguments (#152404)

The warning in issued during the compatibility check makes little sense.
Just remove it as it is confusing.

flang/include/flang/Support/Fortran.h

@@ -95,8 +95,8 @@ static constexpr IgnoreTKRSet ignoreTKRAll{IgnoreTKR::Type, IgnoreTKR::Kind,
 std::string AsFortran(IgnoreTKRSet);
 
 bool AreCompatibleCUDADataAttrs(std::optional<CUDADataAttr>,
-    std::optional<CUDADataAttr>, IgnoreTKRSet, std::optional<std::string> *,
-    bool allowUnifiedMatchingRule, bool isHostDeviceProcedure,
+    std::optional<CUDADataAttr>, IgnoreTKRSet, bool allowUnifiedMatchingRule,
+    bool isHostDeviceProcedure,
     const LanguageFeatureControl *features = nullptr);
 
 static constexpr char blankCommonObjectName[] = "__BLNK__";

flang/lib/Evaluate/characteristics.cpp

@@ -400,7 +400,7 @@ bool DummyDataObject::IsCompatibleWith(const DummyDataObject &actual,
   }
   if (!attrs.test(Attr::Value) &&
       !common::AreCompatibleCUDADataAttrs(cudaDataAttr, actual.cudaDataAttr,
-          ignoreTKR, warning,
+          ignoreTKR,
           /*allowUnifiedMatchingRule=*/false,
           /*=isHostDeviceProcedure*/ false)) {
     if (whyNot) {
@@ -1816,7 +1816,7 @@ bool DistinguishUtils::Distinguishable(
       x.intent != common::Intent::In) {
     return true;
   } else if (!common::AreCompatibleCUDADataAttrs(x.cudaDataAttr, y.cudaDataAttr,
-                 x.ignoreTKR | y.ignoreTKR, nullptr,
+                 x.ignoreTKR | y.ignoreTKR,
                  /*allowUnifiedMatchingRule=*/false,
                  /*=isHostDeviceProcedure*/ false)) {
     return true;

flang/lib/Semantics/check-call.cpp

@@ -1058,12 +1058,11 @@ static void CheckExplicitDataArg(const characteristics::DummyDataObject &dummy,
             dummyName);
       }
     }
-    std::optional<std::string> warning;
     bool isHostDeviceProc{procedure.cudaSubprogramAttrs &&
         *procedure.cudaSubprogramAttrs ==
             common::CUDASubprogramAttrs::HostDevice};
     if (!common::AreCompatibleCUDADataAttrs(dummyDataAttr, actualDataAttr,
-            dummy.ignoreTKR, &warning, /*allowUnifiedMatchingRule=*/true,
+            dummy.ignoreTKR, /*allowUnifiedMatchingRule=*/true,
             isHostDeviceProc, &context.languageFeatures())) {
       auto toStr{[](std::optional<common::CUDADataAttr> x) {
         return x ? "ATTRIBUTES("s +
@@ -1074,10 +1073,6 @@ static void CheckExplicitDataArg(const characteristics::DummyDataObject &dummy,
           "%s has %s but its associated actual argument has %s"_err_en_US,
           dummyName, toStr(dummyDataAttr), toStr(actualDataAttr));
     }
-    if (warning && context.ShouldWarn(common::UsageWarning::CUDAUsage)) {
-      messages.Say(common::UsageWarning::CUDAUsage, "%s"_warn_en_US,
-          std::move(*warning));
-    }
   }
 
   // Warning for breaking F'2023 change with character allocatables

flang/lib/Support/Fortran.cpp

@@ -103,8 +103,8 @@ std::string AsFortran(IgnoreTKRSet tkr) {
 /// dummy argument attribute while `y` represents the actual argument attribute.
 bool AreCompatibleCUDADataAttrs(std::optional<CUDADataAttr> x,
     std::optional<CUDADataAttr> y, IgnoreTKRSet ignoreTKR,
-    std::optional<std::string> *warning, bool allowUnifiedMatchingRule,
-    bool isHostDeviceProcedure, const LanguageFeatureControl *features) {
+    bool allowUnifiedMatchingRule, bool isHostDeviceProcedure,
+    const LanguageFeatureControl *features) {
   bool isCudaManaged{features
           ? features->IsEnabled(common::LanguageFeature::CudaManaged)
           : false};
@@ -145,9 +145,6 @@ bool AreCompatibleCUDADataAttrs(std::optional<CUDADataAttr> x,
                     *y == CUDADataAttr::Shared ||
                     *y == CUDADataAttr::Constant)) ||
             (!y && (isCudaUnified || isCudaManaged))) {
-          if (y && *y == CUDADataAttr::Shared && warning) {
-            *warning = "SHARED attribute ignored"s;
-          }
           return true;
         }
       } else if (*x == CUDADataAttr::Managed) {

flang/test/Semantics/cuf17.cuf

@@ -1,18 +0,0 @@
-! RUN: bbc -emit-hlfir -fcuda %s 2>&1 | FileCheck %s
-
-module mod1
-contains
-
-attributes(device) subroutine sub1(adev)
-  real, device :: adev(10)
-end
-
-attributes(global) subroutine sub2()
-  real, shared :: adev(10)
-  !WARNING: SHARED attribute ignored
-  call sub1(adev)
-end subroutine
-
-end module
-
-! CHECK: warning: SHARED attribute ignored