Initial support for clique-based kernels (#276)

* Initial support for clique-based kernels

src/collectives/device/common_kernel.h

@@ -350,9 +350,14 @@ __device__ int ptrAlign128(T* ptr) { return (uint64_t)ptr % alignof(int32_t); }
 __device__ int ptrAlign128(T* ptr) { return (uint64_t)ptr % alignof(Pack128); }
 #endif
 
+#if defined(__HIP_PLATFORM_HCC__) || defined(__HCC__) || defined(__HIPCC__)
+// Multiply UNROLL by 2 if single source/single destination
+#define AUTOUNROLL (UNROLL*((MINSRCS==1 && MINDSTS==1) ? 2 : 1))
+#else
 // Try to limit consecutive load/stores to 8.
 // Use UNROLL 8 when we have a single source and a single destination, 4 otherwise
 #define AUTOUNROLL (UNROLL*(4/(MINDSTS+MINSRCS)))
+#endif
 
 template<int UNROLL, class FUNC, typename T, int MINSRCS, int MAXSRCS, int MINDSTS, int MAXDSTS>
 __device__ void ReduceOrCopyMulti(const int tid, const int nthreads,