Add name() to CK compute shape throws; enforce mul has 2 args

src/targets/gpu/fuse_ck.cpp

@@ -55,7 +55,7 @@ struct ck_gemm
     {
         check_shapes{inputs, *this}.same_ndims();
         if(inputs.size() < 2)
-            MIGRAPHX_THROW("should have at least two inputs.");
+            MIGRAPHX_THROW(name() + ": should have at least two inputs.");
         auto a = inputs[0];
         auto b = inputs[1];
         for(const auto& input : inputs)
@@ -96,7 +96,7 @@ struct ck_gemm_softmax_gemm
     {
         check_shapes{inputs, *this}.same_ndims();
         if(inputs.size() < 3)
-            MIGRAPHX_THROW("Expected 3 inputs but got " + to_string(inputs.size()));
+            MIGRAPHX_THROW(name() + ": Expected 3 inputs but got " + to_string(inputs.size()));
         auto a  = inputs[0];
         auto b  = inputs[1];
         auto b1 = inputs[2];
@@ -225,7 +225,7 @@ struct find_ck_gemm_softmax_gemm
     {
         auto gemm1 =
             match::skip(match::name("contiguous"))(match::name("dot")(is_ck_gemm().bind("gemm1")));
-        auto mul     = match::name("pointwise")(match::either_arg(0, 1)(
+        auto mul     = match::name("pointwise")(match::nargs(2), match::either_arg(0, 1)(
             match::is_constant().bind("scale"), gemm1))(is_pointwise_scale());
         auto softmax = match::name("softmax")(match::arg(0)(mul)).bind("softmax");