From 804b2353aff7feef565bbbc9d54f9b81221cb489 Mon Sep 17 00:00:00 2001
From: Tom Lin <tom91136@gmail.com>
Date: Mon, 2 Oct 2023 15:21:22 +0100
Subject: [PATCH] Prevent NVHPC from optimising away task barrier (likely a
 bug)

---
 src/omp/fasten.hpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/omp/fasten.hpp b/src/omp/fasten.hpp
index ef5c228..cae2328 100644
--- a/src/omp/fasten.hpp
+++ b/src/omp/fasten.hpp
@@ -12,6 +12,8 @@
 #endif
 #define IMPL_CLS OmpBude
 
+static volatile float discard;
+
 template <size_t PPWI> class IMPL_CLS final : public Bude<PPWI> {
 
   static inline void fasten_main(size_t group, size_t ntypes, size_t nposes, size_t natlig, size_t natpro,        //
@@ -245,6 +247,8 @@ template <size_t PPWI> class IMPL_CLS final : public Bude<PPWI> {
                     poses_0, poses_1, poses_2, poses_3, poses_4, poses_5, //
                     forcefield, energies);
       }
+      #pragma omp target update from(energies[:1])
+      discard = energies[0];
       auto kernelEnd = now();
       sample.kernelTimes.emplace_back(kernelStart, kernelEnd);
     }