[june24] in CODEGEN (backport gg_tt.mad) CPPProcess.cc, replace 'chan…

…nelIds[0] != 0' by 'channelIds != nullptr' (fix segfault madgraph5#892)

Also add the missing fix for computeMatrixElements (I just added -Wunused-parameter otherwise this is not spotted)

Also replace 0 by nullptr for clarity on the channelIDs array

Now both the SIMD and cuda runTest.exe pass without crashing and with success results

epochX/cudacpp/CODEGEN/PLUGIN/CUDACPP_SA_OUTPUT/madgraph/iolibs/template_files/gpu/MatrixElementKernels.cc

@@ -269,7 +269,8 @@ namespace mg5amcGpu
     constexpr unsigned int sharedMemSize = ntpbMAX * sizeof( float );
 #endif
 #ifdef MGONGPU_SUPPORTS_MULTICHANNEL
-    gpuLaunchKernelSharedMem( sigmaKin, m_gpublocks, m_gputhreads, sharedMemSize, m_momenta.data(), m_couplings.data(), m_rndhel.data(), m_rndcol.data(), m_matrixElements.data(), m_channelIds.data(), m_numerators.data(), m_denominators.data(), m_selhel.data(), m_selcol.data() );
+    const unsigned int* pChannelIds = ( useChannelIds ? m_channelIds.data() : nullptr );
+    gpuLaunchKernelSharedMem( sigmaKin, m_gpublocks, m_gputhreads, sharedMemSize, m_momenta.data(), m_couplings.data(), m_rndhel.data(), m_rndcol.data(), m_matrixElements.data(), pChannelIds, m_numerators.data(), m_denominators.data(), m_selhel.data(), m_selcol.data() );
 #else
     gpuLaunchKernelSharedMem( sigmaKin, m_gpublocks, m_gputhreads, sharedMemSize, m_momenta.data(), m_couplings.data(), m_rndhel.data(), m_rndcol.data(), m_matrixElements.data(), m_selhel.data(), m_selcol.data() );
 #endif

epochX/cudacpp/CODEGEN/PLUGIN/CUDACPP_SA_OUTPUT/madgraph/iolibs/template_files/gpu/process_function_definitions.inc

@@ -308,8 +308,8 @@ namespace mg5amcCpu
       // NB: calculate_wavefunctions ADDS |M|^2 for a given ihel to the running sum of |M|^2 over helicities for the given event(s)
       constexpr fptype_sv* jamp2_sv = nullptr; // no need for color selection during helicity filtering
 #ifdef MGONGPU_SUPPORTS_MULTICHANNEL
-      constexpr unsigned int* channelId = nullptr; // disable multichannel single-diagram enhancement
-      calculate_wavefunctions( ihel, allmomenta, allcouplings, allMEs, channelId, allNumerators, allDenominators, jamp2_sv );
+      constexpr unsigned int* channelIds = nullptr; // disable multichannel single-diagram enhancement
+      calculate_wavefunctions( ihel, allmomenta, allcouplings, allMEs, channelIds, allNumerators, allDenominators, jamp2_sv );
 #else
       calculate_wavefunctions( ihel, allmomenta, allcouplings, allMEs, jamp2_sv );
 #endif
@@ -372,8 +372,8 @@ namespace mg5amcCpu
         constexpr fptype_sv* jamp2_sv = nullptr; // no need for color selection during helicity filtering
         //std::cout << "sigmaKin_getGoodHel ihel=" << ihel << ( isGoodHel[ihel] ? " true" : " false" ) << std::endl;
 #ifdef MGONGPU_SUPPORTS_MULTICHANNEL
-        constexpr unsigned int* channelId = nullptr; // disable multichannel single-diagram enhancement
-        calculate_wavefunctions( ihel, allmomenta, allcouplings, allMEs, channelId, allNumerators, allDenominators, jamp2_sv, ievt00 );
+        constexpr unsigned int* channelIds = nullptr; // disable multichannel single-diagram enhancement
+        calculate_wavefunctions( ihel, allmomenta, allcouplings, allMEs, channelIds, allNumerators, allDenominators, jamp2_sv, ievt00 );
 #else
         calculate_wavefunctions( ihel, allmomenta, allcouplings, allMEs, jamp2_sv, ievt00 );
 #endif

epochX/cudacpp/CODEGEN/PLUGIN/CUDACPP_SA_OUTPUT/madgraph/iolibs/template_files/gpu/process_sigmaKin_function.inc

@@ -70,7 +70,7 @@
     }
 #ifdef MGONGPU_SUPPORTS_MULTICHANNEL
     // Event-by-event random choice of color #402
-    if( channelIds[0] != 0 ) // no event-by-event choice of color if channelId == 0 (fix FPE #783)
+    if( channelIds != nullptr ) // no event-by-event choice of color if channelIds == nullptr (fix FPE #783, fix segfault #892)
     {
       const unsigned int iconfigC = mgOnGpu::channelId_to_iconfigC[CID_ACCESS::kernelAccessConst( channelIds )]; // coloramps.h uses a channel ordering not the diagram id
       fptype targetamp[ncolor] = { 0 };
@@ -185,7 +185,7 @@
       }
 #ifdef MGONGPU_SUPPORTS_MULTICHANNEL // multichannel enabled (random color choice)
       // Event-by-event random choice of color #402
-      if( channelIds[0] != 0 ) // no event-by-event choice of color if channelId == 0 (fix FPE #783)
+      if( channelIds != nullptr ) // no event-by-event choice of color if channelIds == nullptr (fix FPE #783, fix segfault #892)
       {
         uint_sv ichannelIds = CID_ACCESS::kernelAccessConst( channelIds ); // coloramps.h uses a channel ordering not the diagram id
         fptype_sv targetamp[ncolor] = { 0 };
@@ -271,7 +271,7 @@
 #ifdef MGONGPUCPP_GPUIMPL
     allMEs[ievt] /= helcolDenominators[0];
 #ifdef MGONGPU_SUPPORTS_MULTICHANNEL
-    if( channelIds[0] != 0 ) allMEs[ievt] *= allNumerators[ievt] / allDenominators[ievt];
+    if( channelIds != nullptr ) allMEs[ievt] *= allNumerators[ievt] / allDenominators[ievt]; // fix segfault #892 (not 'channelIds[0] != 0')
 #endif
 #else
     for( int ipagV = 0; ipagV < npagV; ++ipagV )
@@ -281,7 +281,7 @@
       fptype_sv& MEs_sv = E_ACCESS::kernelAccess( MEs );
       MEs_sv /= helcolDenominators[0];
 #ifdef MGONGPU_SUPPORTS_MULTICHANNEL
-      if( channelIds[0] != 0 )
+      if( channelIds != nullptr ) // fix segfault #892 (not 'channelIds[0] != 0')
       {
         fptype* numerators = NUM_ACCESS::ieventAccessRecord( allNumerators, ievt0 );
         fptype* denominators = DEN_ACCESS::ieventAccessRecord( allDenominators, ievt0 );

epochX/cudacpp/CODEGEN/PLUGIN/CUDACPP_SA_OUTPUT/model_handling.py

@@ -1915,8 +1915,8 @@ def super_get_matrix_element_calls(self, matrix_element, color_amplitudes, multi
       // Numerators and denominators for the current event (CUDA) or SIMD event page (C++)
       fptype_sv& numerators_sv = NUM_ACCESS::kernelAccess( numerators );
       fptype_sv& denominators_sv = DEN_ACCESS::kernelAccess( denominators );
-      uint_sv channelids_sv; // this is only filled (and used) if channelIds != 0
-      if( channelIds != 0 )
+      uint_sv channelids_sv; // this is only filled (and used) if channelIds != nullptr
+      if( channelIds != nullptr )
         channelids_sv = CID_ACCESS::kernelAccessConst( channelIds ); // fix #895
 #endif""")
         diagrams = matrix_element.get('diagrams')
@@ -1948,7 +1948,7 @@ def super_get_matrix_element_calls(self, matrix_element, color_amplitudes, multi
                         ###res.append("if( channelId == %i ) numerators_sv += cxabs2( amp_sv[0] );" % diag_to_config[id_amp]) # BUG #472
                         ###res.append("if( channelId == %i ) numerators_sv += cxabs2( amp_sv[0] );" % id_amp) # wrong fix for BUG #472
                         res.append("#ifdef MGONGPU_SUPPORTS_MULTICHANNEL")
-                        res.append("if( channelIds != 0 )")
+                        res.append("if( channelIds != nullptr )")
                         res.append("{")
                         res.append("#if defined __CUDACC__ or !defined MGONGPU_CPPSIMD")
                         res.append("  if( channelids_sv == %i ) numerators_sv += cxabs2( amp_sv[0] );" % diagram.get('number'))