GPU: three additional Metal adaptations

GPUCommonAlgorithm::sortOnDevice takes an auto parameter, which is C++20. It is already skipped for OpenCL, at C++17, and MSL 4.1 reports C++17 as well.

GPUTPCTrackParam::TransportToXAlpha declares its material constants static at function scope, which MSL rejects; constexpr without static is accepted, as in SMatrixGPU.

Guard SMatrixGPU C++20 code using __cplusplus version macro.

Author: ktf

Common/MathUtils/include/MathUtils/SMatrixGPU.h

@@ -518,7 +518,7 @@ class SMatrixGPU
   R mRep;
 };
 
-#if !defined(__OPENCL__) && !defined(__METAL__) // TODO: current C++ for OpenCL 2021 and MSL 4.1 are both at C++17, so no concepts. But we don't need this trick there anyway, so we can just hide it.
+#if __cplusplus >= 202002L // the constraint below is a requires-clause; we do not need the trick where there are no concepts
 template <class T, unsigned int D1, unsigned int D2, class R, typename Y, typename X = Y>
   requires(sizeof(typename X::traits_type::pos_type) != 0) // do not provide a template to fair::Logger, etc... (pos_type is a member type of all std::ostream classes)
 GPUd() X& operator<<(Y& y, const SMatrixGPU<T, D1, D2, R>&)

GPU/Common/GPUCommonAlgorithm.h

@@ -41,7 +41,7 @@ class GPUCommonAlgorithm
   GPUd() static void sortInBlock(T* begin, T* end, const S& comp);
   template <class T, class S>
   GPUd() static void sortDeviceDynamic(T* begin, T* end, const S& comp);
-#ifndef __OPENCL__
+#if __cplusplus >= 202002L // sortOnDevice takes an auto parameter
   template <class T, class S>
   GPUh() static void sortOnDevice(auto* rec, int32_t stream, T* begin, size_t N, const S& comp);
 #endif

GPU/GPUTracking/SectorTracker/GPUTPCTrackParam.cxx

@@ -304,10 +304,10 @@ GPUd() bool GPUTPCTrackParam::TransportToXWithMaterial(float x, GPUTPCTrackLinea
 {
   //* Transport the track parameters to X=x  taking into account material budget
 
-  static constexpr float kRho = 1.025e-3f;   // [g/cm^3]
-  static constexpr float kRadLen = 28811.7f; //[cm]
+  constexpr float kRho = 1.025e-3f;   // [g/cm^3]
+  constexpr float kRadLen = 28811.7f; //[cm]
 
-  static constexpr float kRadLenInv = 1.f / kRadLen;
+  constexpr float kRadLenInv = 1.f / kRadLen;
   float dl;
 
   if (!TransportToX(x, t0, Bz, maxSinPhi, &dl)) {