# [WARNING GRT-0350] Missing route to pin iregister_read/io_bypass_1_bits_data[0].

Tool: Global Routing

Subcategory: Parasitics estimation issue

## Conversation

### oharboe
This is for the top level of MegaBoom that I'm playing around with.

Is this warning telling me that it can't find a route for the buffer tree for the pin in the warning?

It looks like this buffer tree is going from the iregister_read macro to the ALUExeUnit, which traverses Rob(reorder buffer), rename stage and the memory issue unit. The mpl2 macro placement is unfortunate here...


![image](https://github.com/The-OpenROAD-Project/OpenROAD/assets/2798822/e3c6b965-bf83-403c-9dd5-70413735a8ca)



![image](https://github.com/The-OpenROAD-Project/OpenROAD/assets/2798822/c2a76f06-f286-4b5a-8bc7-2fc0219bc9f8)


### maliberty
@eder-matheus please respond

### eder-matheus
@oharboe @maliberty This warning is related to the estimate_parasitics using global route parasitics. It usually happens when a routing topology is not correctly translated to the parasitics estimation structures. I will look into the test case and fix the cause of this bug.