[LCG] Add the other simple edge insertion API to the call graph. This

just connects an SCC to one of its descendants directly. Not much of an
impact. The last one is the hard one -- connecting an SCC to one of its
ancestors, and thereby forming a cycle such that we have to merge all
the SCCs participating in the cycle.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207751 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 53 insertions, 0 deletions

diff --git a/unittests/Analysis/LazyCallGraphTest.cpp b/unittests/Analysis/LazyCallGraphTest.cpp
index 24ca2c9433..039206a1d7 100644
--- a/unittests/Analysis/LazyCallGraphTest.cpp
+++ b/unittests/Analysis/LazyCallGraphTest.cpp
@@ -452,6 +452,59 @@ TEST(LazyCallGraphTest, IntraSCCEdgeInsertion) {
   EXPECT_EQ(&SCC, CG1.lookupSCC(C));
 }
 
+TEST(LazyCallGraphTest, OutgoingSCCEdgeInsertion) {
+  std::unique_ptr<Module> M = parseAssembly(
+      "define void @a() {\n"
+      "entry:\n"
+      "  call void @b()\n"
+      "  call void @c()\n"
+      "  ret void\n"
+      "}\n"
+      "define void @b() {\n"
+      "entry:\n"
+      "  call void @d()\n"
+      "  ret void\n"
+      "}\n"
+      "define void @c() {\n"
+      "entry:\n"
+      "  call void @d()\n"
+      "  ret void\n"
+      "}\n"
+      "define void @d() {\n"
+      "entry:\n"
+      "  ret void\n"
+      "}\n");
+  LazyCallGraph CG(*M);
+
+  // Force the graph to be fully expanded.
+  for (LazyCallGraph::SCC &C : CG.postorder_sccs())
+    (void)C;
+
+  LazyCallGraph::Node &A = *CG.lookup(lookupFunction(*M, "a"));
+  LazyCallGraph::Node &B = *CG.lookup(lookupFunction(*M, "b"));
+  LazyCallGraph::Node &C = *CG.lookup(lookupFunction(*M, "c"));
+  LazyCallGraph::Node &D = *CG.lookup(lookupFunction(*M, "d"));
+  LazyCallGraph::SCC &AC = *CG.lookupSCC(A);
+  LazyCallGraph::SCC &BC = *CG.lookupSCC(B);
+  LazyCallGraph::SCC &CC = *CG.lookupSCC(C);
+  LazyCallGraph::SCC &DC = *CG.lookupSCC(D);
+  EXPECT_TRUE(AC.isAncestorOf(BC));
+  EXPECT_TRUE(AC.isAncestorOf(CC));
+  EXPECT_TRUE(AC.isAncestorOf(DC));
+  EXPECT_TRUE(DC.isDescendantOf(AC));
+  EXPECT_TRUE(DC.isDescendantOf(BC));
+  EXPECT_TRUE(DC.isDescendantOf(CC));
+
+  EXPECT_EQ(2, std::distance(A.begin(), A.end()));
+  AC.insertOutgoingEdge(A, D);
+  EXPECT_EQ(3, std::distance(A.begin(), A.end()));
+  EXPECT_TRUE(AC.isParentOf(DC));
+  EXPECT_EQ(&AC, CG.lookupSCC(A));
+  EXPECT_EQ(&BC, CG.lookupSCC(B));
+  EXPECT_EQ(&CC, CG.lookupSCC(C));
+  EXPECT_EQ(&DC, CG.lookupSCC(D));
+}
+
 TEST(LazyCallGraphTest, IntraSCCEdgeRemoval) {
   // A nice fully connected (including self-edges) SCC.
   std::unique_ptr<Module> M1 = parseAssembly(