[Dominators] Visit affected node candidates found at different root levels
Summary:
This patch attempts to fix the DomTree incremental insertion bug found here [[ https://bugs.llvm.org/show_bug.cgi?id=35969 | PR35969 ]] .
When performing an insertion into a piece of unreachable CFG, we may find the same not at different levels. When this happens, the node can turn out to be affected when we find it starting from a node with a lower level in the tree. The level at which we start visitation affects if we consider a node affected or not.
This patch tracks the lowest level at which each node was visited during insertion and allows it to be visited multiple times, if it can cause it to be considered affected.
Reviewers: brzycki, davide, dberlin, grosser
Reviewed By: brzycki
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D42231
llvm-svn: 322993
diff --git a/llvm/unittests/IR/DominatorTreeTest.cpp b/llvm/unittests/IR/DominatorTreeTest.cpp
index bf5aced..4666f93 100644
--- a/llvm/unittests/IR/DominatorTreeTest.cpp
+++ b/llvm/unittests/IR/DominatorTreeTest.cpp
@@ -925,3 +925,28 @@
}
}
}
+
+TEST(DominatorTree, InsertIntoIrreducible) {
+ std::vector<CFGBuilder::Arc> Arcs = {
+ {"0", "1"},
+ {"1", "27"}, {"1", "7"},
+ {"10", "18"},
+ {"13", "10"},
+ {"18", "13"}, {"18", "23"},
+ {"23", "13"}, {"23", "24"},
+ {"24", "1"}, {"24", "18"},
+ {"27", "24"}};
+
+ CFGHolder Holder;
+ CFGBuilder B(Holder.F, Arcs, {{Insert, {"7", "23"}}});
+ DominatorTree DT(*Holder.F);
+ EXPECT_TRUE(DT.verify());
+
+ B.applyUpdate();
+ BasicBlock *From = B.getOrAddBlock("7");
+ BasicBlock *To = B.getOrAddBlock("23");
+ DT.insertEdge(From, To);
+
+ EXPECT_TRUE(DT.verify());
+}
+