Fix a bug in VPR when reading tileable rr_graph (--read_rr_graph)

[rs-mahdi]

Motivate of the pull request

• To address an existing issue. If so, please provide a link to the issue:
• Breaking new feature. If so, please describe details in the description part.

Describe the technical details

What is currently done? (Provide issue link if applicable)

I modified VPR source code to correctly read rr_graph when it is tileable. Before this change, VPR had not been checking if the input rr_graph is tileable or not. When the rr_graph is tileable, ptc# for wires changes through different coordinates. However, VPR was assigning the same ptc# to all coordinates that a wire can cover.

What does this pull request change?

How the ptc# is assigned to wires longer than 1. This assignment is done run-time by VPR to create its internal data structure.

Which part of the code base require a change

• Build compatibility
• Documentation
• Regression tests
• Continous Integration (CI) scripts

Impact of the pull request

• Require a change on Quality of Results (QoR)
• Break back-compatibility. If so, please list who may be influenced.