IR: Add MDNode::isDistinct()
Add API to indicate whether an `MDNode` is distinct. A distinct node is
not stored in the MDNode uniquing tables, and will never be returned by
`MDNode::get()`.
Although distinct nodes are only currently created by uniquing
collisions (when operands change), PR22111 will allow these nodes to be
explicitly created.
llvm-svn: 225401
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index ef071b3..9c4403c 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -222,6 +222,33 @@
EXPECT_EQ(N, NullOp);
}
+TEST_F(MDNodeTest, DistinctOnUniquingCollision) {
+ // !{}
+ MDNode *Empty = MDNode::get(Context, None);
+ ASSERT_TRUE(Empty->isResolved());
+ EXPECT_FALSE(Empty->isDistinct());
+
+ // !{!{}}
+ Metadata *Wrapped1Ops[] = {Empty};
+ MDNode *Wrapped1 = MDNode::get(Context, Wrapped1Ops);
+ ASSERT_EQ(Empty, Wrapped1->getOperand(0));
+ ASSERT_TRUE(Wrapped1->isResolved());
+ EXPECT_FALSE(Wrapped1->isDistinct());
+
+ // !{!{!{}}}
+ Metadata *Wrapped2Ops[] = {Wrapped1};
+ MDNode *Wrapped2 = MDNode::get(Context, Wrapped2Ops);
+ ASSERT_EQ(Wrapped1, Wrapped2->getOperand(0));
+ ASSERT_TRUE(Wrapped2->isResolved());
+ EXPECT_FALSE(Wrapped2->isDistinct());
+
+ // !{!{!{}}} => !{!{}}
+ Wrapped2->replaceOperandWith(0, Empty);
+ ASSERT_EQ(Empty, Wrapped2->getOperand(0));
+ EXPECT_TRUE(Wrapped2->isDistinct());
+ EXPECT_FALSE(Wrapped1->isDistinct());
+}
+
typedef MetadataTest MetadataAsValueTest;
TEST_F(MetadataAsValueTest, MDNode) {