hdl.xfrm: avoid cycles in union-find graph in LHSGroupAnalyzer.

2018-12-22 22:19:14 +00:00 · 2018-12-22 22:19:14 +00:00 · 621dddebfd
commit 621dddebfd
parent 3448953f61
2 changed files with 16 additions and 0 deletions
--- a/nmigen/hdl/xfrm.py
+++ b/nmigen/hdl/xfrm.py
@ -298,6 +298,8 @@ class LHSGroupAnalyzer(StatementVisitor):
        root_group = self.find(root)
        for leaf in leaves:
            leaf_group = self.find(leaf)
+            if root_group == leaf_group:
+                continue
            self.unions[leaf_group] = root_group

    def groups(self):