kokkos-kernels: gemm fails on host Views with rocBLAS enabled

[japlews]

Bug Report

We are seeing this in Sierra builds. Compile with HIP and rocBLAS, and the below code fails to build. It attempts to run on the device, despite that execution_space is Kokkos::Serial. Here's a MRE:

TEST(KokkosGEMMBug, hipEnabledGemmHostViewFails) {
    using ExecSpace = Kokkos::DefaultHostExecutionSpace;
    const double alpha = 1.0;
    const double beta = 0.0;
    Kokkos::View<double*, ExecSpace> a, b, c;
    KokkosBlas::gemm("N", "N", alpha, b, c, beta, a);
}

It looks like there is some compile-time checking missing in KokkosKernels Level 3 BLAS...

[japlews]

@lucbv can you confirm whether this issue is still in Kokkos Kernels itself?

[csiefer2]

@cwpearson

[lucbv]

I am having a look at this