Fix OpenMP 5.1 atomics

* Workaround clang not recognizing ternay expression * Implement atomicInc/atomicDec via omp critical Fixes: #2170
alpaka-group · Sep 27, 2023 · 1846aa1 · 1846aa1
1 parent 1ee0426
commit 1846aa1
Showing 1 changed file with 14 additions and 30 deletions.
diff --git a/include/alpaka/atomic/AtomicOmpBuiltIn.hpp b/include/alpaka/atomic/AtomicOmpBuiltIn.hpp
@@ -187,7 +187,8 @@ namespace alpaka
 #        pragma omp atomic capture compare
                 {
                     old = ref;
-                    ref = (ref <= value) ? ref : value;
+                    if(value < ref)
+                        ref = value;
                 }
                 return old;
             }
@@ -205,7 +206,8 @@ namespace alpaka
 #        pragma omp atomic capture compare
                 {
                     old = ref;
-                    ref = (ref >= value) ? ref : value;
+                    if(value > ref)
+                        ref = value;
                 }
                 return old;
             }
@@ -217,21 +219,12 @@ namespace alpaka
         {
             ALPAKA_FN_HOST static auto atomicOp(AtomicOmpBuiltIn const&, T* const addr, T const& value) -> T
             {
+                // TODO(bgruber): atomic increment with wrap around is not implementable in OpenMP 5.1
                 T old;
-                auto& ref(*addr);
-// atomically update ref, but capture the original value in old
-#        if BOOST_COMP_GNUC
-#            pragma GCC diagnostic push
-#            pragma GCC diagnostic ignored "-Wconversion"
-#        endif
-#        pragma omp atomic capture compare
+#        pragma omp critical(AlpakaOmpAtomicOp)
                 {
-                    old = ref;
-                    ref = ((ref >= value) ? 0 : (ref + 1));
+                    old = AtomicInc{}(addr, value);
                 }
-#        if BOOST_COMP_GNUC
-#            pragma GCC diagnostic pop
-#        endif
                 return old;
             }
         };
@@ -242,21 +235,12 @@ namespace alpaka
         {
             ALPAKA_FN_HOST static auto atomicOp(AtomicOmpBuiltIn const&, T* const addr, T const& value) -> T
             {
+                // TODO(bgruber): atomic decrement with wrap around is not implementable in OpenMP 5.1
                 T old;
-                auto& ref(*addr);
-// atomically update ref, but capture the original value in old
-#        if BOOST_COMP_GNUC
-#            pragma GCC diagnostic push
-#            pragma GCC diagnostic ignored "-Wconversion"
-#        endif
-#        pragma omp atomic capture compare
+#        pragma omp critical(AlpakaOmpAtomicOp)
                 {
-                    old = ref;
-                    ref = ((ref == 0) || (ref > value)) ? value : (ref - 1);
+                    old = AtomicDec{}(addr, value);
                 }
-#        if BOOST_COMP_GNUC
-#            pragma GCC diagnostic pop
-#        endif
                 return old;
             }
         };
@@ -293,8 +277,8 @@ namespace alpaka
             ALPAKA_FN_HOST static auto atomicOp(AtomicOmpBuiltIn const&, T* const addr, T const& value) -> T
             {
                 T old;
-// \TODO: Currently not only the access to the same memory location is protected by a mutex but all atomic ops on all
-// threads.
+                // \TODO: Currently not only the access to the same memory location is protected by a mutex but all
+                // atomic ops on all threads.
 #        pragma omp critical(AlpakaOmpAtomicOp)
                 {
                     old = TOp()(addr, value);
@@ -309,8 +293,8 @@ namespace alpaka
                 T const& value) -> T
             {
                 T old;
-// \TODO: Currently not only the access to the same memory location is protected by a mutex but all atomic ops on all
-// threads.
+                // \TODO: Currently not only the access to the same memory location is protected by a mutex but all
+                // atomic ops on all threads.
 #        pragma omp critical(AlpakaOmpAtomicOp2)
                 {
                     old = TOp()(addr, compare, value);