avoid compier error

```
/mem/view/Traits.hpp:124:20: error: not eliding copy on return [-Werror,-Wnrvo]
3111
14:27:41
  124 |             return pitchBytes;
```

and

```
block/sync/BlockSyncUniformCudaHipBuiltIn.hpp:76:32: error: 'tmp' may be duplicated when built into a shared library: it is mutable, with external linkage and hidden visibility [-Werror,-Wunique-object-duplication]
3169
08:41:14
   76 |                 __shared__ int tmp;
```

Author: psychocoderHPC

include/alpaka/block/sync/BlockSyncUniformCudaHipBuiltIn.hpp

@@ -47,8 +47,15 @@ namespace alpaka
                 int predicate) -> int
             {
 #        if defined(__HIP_ARCH_HAS_SYNC_THREAD_EXT__) && __HIP_ARCH_HAS_SYNC_THREAD_EXT__ == 0 && ALPAKA_COMP_HIP
+#            if ALPAKA_COMP_CLANG
+#                pragma clang diagnostic push
+#                pragma clang diagnostic ignored "-Wattributes"
+#            endif
                 // workaround for unsupported syncthreads_* operation on AMD hardware without sync extension
                 __shared__ int tmp;
+#            if ALPAKA_COMP_CLANG
+#                pragma clang diagnostic pop
+#            endif
                 __syncthreads();
                 if(threadIdx.x == 0)
                     tmp = 0;

include/alpaka/core/DemangleTypeNames.hpp

@@ -80,7 +80,7 @@ namespace alpaka::core
             std::copy(embeddedType.data() + start, embeddedType.data() + end, storage.data());
             storage[length] = '\0';
 
-            return storage;
+            return std::move(storage);
         }
 
         // Store the demangled type name as a null-terminated array of bytes.

include/alpaka/mem/view/Traits.hpp

@@ -97,7 +97,7 @@ namespace alpaka
             if constexpr(dim > 1)
                 for(TIdx i = TDim::value - 1; i > 0; i--)
                     pitchBytes[i - 1] = extent[i] * pitchBytes[i];
-            return pitchBytes;
+            return std::move(pitchBytes);
         }
 
         //! Calculate the pitches from the extents and the one-dimensional pitch.
@@ -121,7 +121,14 @@ namespace alpaka
             if constexpr(dim > 2)
                 for(TIdx i = TDim::value - 2; i > 0; i--)
                     pitchBytes[i - 1] = extent[i] * pitchBytes[i];
+#if ALPAKA_COMP_CLANG
+#    pragma clang diagnostic push
+#    pragma clang diagnostic ignored "-Wnrvo"
+#endif
             return pitchBytes;
+#if ALPAKA_COMP_CLANG
+#    pragma clang diagnostic pop
+#endif
         }
 
     } // namespace detail

include/alpaka/workdiv/WorkDivHelpers.hpp

@@ -79,7 +79,7 @@ namespace alpaka
                 }
             }
 
-            return divisorSet;
+            return std::move(divisorSet);
         }
     } // namespace detail
 
@@ -160,7 +160,7 @@ namespace alpaka
             Vec r;
             for(DimLoopInd i(0u); i < TDim::value; ++i)
                 r[i] = core::divCeil(gridElemExtent[i], clippedThreadElemExtent[i]);
-            return r;
+            return std::move(r);
         }();
 
         ///////////////////////////////////////////////////////////////////
@@ -278,7 +278,7 @@ namespace alpaka
             Vec r;
             for(DimLoopInd i = 0; i < TDim::value; ++i)
                 r[i] = core::divCeil(gridThreadExtent[i], blockThreadExtent[i]);
-            return r;
+            return std::move(r);
         }();