Drop unneeded workaround

This apparently is fixed with the new ROOT and it actually breaks
with the latest system clang on macOS.

Author: ktf

Common/MathUtils/include/MathUtils/Cartesian.h

@@ -285,24 +285,6 @@ GPUdi() SMatrix<T, D1, D1, MatRepSym<T, D1>> Similarity(const SMatrix<T, D1, D2,
 std::ostream& operator<<(std::ostream& os, const o2::math_utils::Rotation2Df_t& t);
 std::ostream& operator<<(std::ostream& os, const o2::math_utils::Rotation2Dd_t& t);
 
-namespace std
-{
-
-/// Defining Point3D explicitly as trivially copyable
-///
-/// std::is_trivially_copyable<ROOT::Math::Cartesian3D<T>> fails because the class
-/// implements a copy constructor, although it does not much more than the default copy
-/// constructor. We need Point3D to fulfill the condition in order to make types
-/// inheriting from it or using it as member can be safely detected as messageable.
-///
-/// We believe that Point3D is messageable and explicitly specialize the type trait.
-/// There is a unit test for checking trivial copy
-/// This is a workaround, we will also make suggestions to fix the cause in ROOT itself
-/// TODO: delete once it is fixed in ROOT
-template <typename T>
-struct is_trivially_copyable<o2::math_utils::Point3D<T>> : std::true_type {
-};
-} // namespace std
 #endif // Disable for GPU
 
 #endif

Common/MathUtils/include/MathUtils/CartesianGPU.h

@@ -16,6 +16,7 @@
 #define ALICEO2_CARTESIANGPU_H
 
 #include "GPUCommonDef.h"
+#include "GPUCommonTypeTraits.h"
 
 namespace o2::math_utils
 {
@@ -43,6 +44,9 @@ struct GPUPoint3D : public GPUPoint2D<T, I> {
   GPUd() float R() const { return o2::gpu::CAMath::Sqrt(GPUPoint2D<T, I>::xx * GPUPoint2D<T, I>::xx + GPUPoint2D<T, I>::yy * GPUPoint2D<T, I>::yy + zz * zz); }
   GPUd() void SetZ(float v) { zz = v; }
   T zz;
+#if (!defined(GPUCA_GPUCODE_DEVICE) || defined(__CUDACC__) || defined(__HIPCC__)) && !defined(GPUCA_GPUCODE_COMPILEKERNELS)
+  static_assert(std::is_trivially_copyable_v<GPUPoint3D>);
+#endif
 };
 } // namespace detail