Handle scalar conversion primarily empty scalars

Need to have this to force the output to be a compatible to both the else/then cases

Still a work in progress

src/onnx/parse_if.cpp

@@ -69,7 +69,8 @@ struct parse_if : op_parser<parse_if>
         assert(then_out_shapes.size() == else_out_shapes.size());
 
         // Must have the same type for both if/else blocks by onnx spec
-        if(then_out_shapes.at(0).type() != else_out_shapes.at(0).type())
+        if(then_out_shapes.at(0).type() != else_out_shapes.at(0).type() &&
+           (then_out_shapes.at(0).elements() > 0) && (else_out_shapes.at(0).elements() > 0))
         {
             MIGRAPHX_THROW("PARSE_IF: " + info.name +
                            " then and else sub_grahps must have same output type! " +
@@ -79,6 +80,29 @@ struct parse_if : op_parser<parse_if>
 
         if(not then_out_shapes.at(0).dynamic() && not else_out_shapes.at(0).dynamic())
         {
+            if(then_out_shapes.at(0).scalar() && not else_out_shapes.at(0).scalar())
+            {
+                migraphx::shape s{else_out_shapes.at(0).type(),
+                                  else_out_shapes.at(0).lens(),
+                                  else_out_shapes.at(0).strides()};
+                auto reshape_ins = then_mdl->insert_instruction(
+                    std::prev(then_mdl->end()),
+                    migraphx::make_op("broadcast", {{"out_lens", s.lens()}}),
+                    std::prev(then_mdl->end())->inputs().front());
+                then_mdl->replace_return({reshape_ins});
+            }
+            else if(not then_out_shapes.at(0).scalar() && else_out_shapes.at(0).scalar())
+            {
+                migraphx::shape s{then_out_shapes.at(0).type(),
+                                  then_out_shapes.at(0).lens(),
+                                  then_out_shapes.at(0).strides()};
+                auto reshape_ins = else_mdl->insert_instruction(
+                    std::prev(else_mdl->end()),
+                    migraphx::make_op("broadcast", {{"out_lens", s.lens()}}),
+                    std::prev(else_mdl->end())->inputs().front());
+                else_mdl->replace_return({reshape_ins});
+            }
+
             // First dimension must agree
             if(then_out_shapes.at(0).lens().at(0) != else_out_shapes.at(0).lens().at(0))
             {
@@ -90,6 +114,7 @@ struct parse_if : op_parser<parse_if>
             auto then_out_strides = then_out_shapes.at(0).strides();
             auto else_out_strides = else_out_shapes.at(0).strides();
 
+            // Generate compatible output types based on largest dimension with rank 1 tensor
             if(then_out_strides.size() > else_out_strides.size())
             {
                 auto reshape_ins = else_mdl->insert_instruction(