Multiple device error (#690)

* Multiple device error

* Update src/Compiler.jl

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Update src/Compiler.jl

Co-authored-by: Mosè Giordano <[email protected]>

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Mosè Giordano <[email protected]>

Author: 3 people

src/Compiler.jl

@@ -1049,6 +1049,13 @@ function compile_xla(f, args; client=nothing, optimize=true, no_nan=false, devic
             end
         end
 
+        num_devices = XLA.ClientNumAddressableDevices(client)
+        if num_devices != 1
+            error(
+                "Unsupported client with multiple addressible devices (we need to pass right shard data)",
+            )
+        end
+
         # compile MLIR module to XLA executable
         exec = XLA.Compile(client, mod)
         (