diff options
Diffstat (limited to 'src/main')
| -rw-r--r-- | src/main/scala/firrtl/transforms/CheckCombLoops.scala | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/src/main/scala/firrtl/transforms/CheckCombLoops.scala b/src/main/scala/firrtl/transforms/CheckCombLoops.scala index a4dad11b..e1e6cf63 100644 --- a/src/main/scala/firrtl/transforms/CheckCombLoops.scala +++ b/src/main/scala/firrtl/transforms/CheckCombLoops.scala @@ -199,8 +199,12 @@ class CheckCombLoops extends Transform { val moduleGraph = DiGraph(internalDeps) moduleGraphs(m.name) = moduleGraph simplifiedModuleGraphs(m.name) = moduleGraphs(m.name).simplify((m.ports map { p => LogicNode(p.name) }).toSet) - for (scc <- moduleGraphs(m.name).findSCCs.filter(_.length > 1)) { - val sccSubgraph = moduleGraphs(m.name).subgraph(scc.toSet) + // Find combinational nodes with self-edges; this is *NOT* the same as length-1 SCCs! + for (unitLoopNode <- moduleGraph.getVertices.filter(v => moduleGraph.getEdges(v).contains(v))) { + errors.append(new CombLoopException(m.info, m.name, Seq(unitLoopNode.name))) + } + for (scc <- moduleGraph.findSCCs.filter(_.length > 1)) { + val sccSubgraph = moduleGraph.subgraph(scc.toSet) val cycle = findCycleInSCC(sccSubgraph) (cycle zip cycle.tail).foreach({ case (a,b) => require(moduleGraph.getEdges(a).contains(b)) }) val expandedCycle = expandInstancePaths(m.name, moduleGraphs, moduleDeps, Seq(m.name), cycle.reverse) |