Skip to content

use maximum start_x from overlapping blockages found when cutting rows #10161

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
openroad-ci wants to merge 1 commit into
base: master
Choose a base branch
from
+3 −2
Open

use maximum start_x from overlapping blockages found when cutting rows #10161

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 3 additions & 2 deletions src/odb/src/db/util.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -101,8 +101,9 @@ static void cutRow(dbBlock* block,
const int seg_end
= makeSiteLoc(blockage.first, site_width, true, start_origin_x);
segments.emplace_back(start_origin_x, seg_end);
start_origin_x
= makeSiteLoc(blockage.second, site_width, false, start_origin_x);
start_origin_x = std::max(
start_origin_x,
makeSiteLoc(blockage.second, site_width, false, start_origin_x));
Comment on lines +104 to +106
Copy link
Copy Markdown
Contributor

@gemini-code-assist gemini-code-assist bot Apr 16, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

high

While this change correctly updates start_origin_x for overlapping blockages, it doesn't prevent the creation of invalid segments. If a blockage overlaps with a previous one, start_origin_x could be greater than blockage.first in the next iteration. This would cause seg_end (calculated on line 102) to be less than start_origin_x, leading to an invalid segment being created on line 103.

A check should be added before line 103 to ensure seg_end > start_origin_x, for example:

if (seg_end > start_origin_x) {
  segments.emplace_back(start_origin_x, seg_end);
}

A more robust long-term solution would be to merge the overlapping row_blockage_xs intervals after sorting. This would simplify the loop and make the logic clearer.

References
  1. When analyzing code within a loop, consider the entire loop structure. Operations at the beginning of the loop or pre-processing (like merging intervals) can affect the logic within the loop body, potentially simplifying it or making certain checks redundant.

}
// Last segment: from after the last blockage to the row's right edge
segments.emplace_back(start_origin_x, row_bb.xMax());
Expand Down
Loading