[llvm] [IR] Fix Module move-assignment missing NamedMDSymTab, ComdatSymTab and Parent update (PR #175501)

[Aiden Grossman via llvm-commits]

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@@ -423,6 +423,13 @@ define void @Foo2() {
     ASSERT_EQ(GV2->getParent(), &*M2);
     *M1 = std::move(*M2);
     ASSERT_EQ(GV2->getParent(), &*M1);
+    
+    ASSERT_NE(M1->getNamedMetadata("foo2"), nullptr);
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boomanaiden154 wrote:

Given it doesn't seem like there's test coverage of this anywhere else, it would be good if we could actually assert a value here rather than just asserting that we do not get `nullptr`.

These calls are also probably better off as `EXPECT_*` instead of `ASSERT_*` given they can all be run independently, but given that's consistent with the rest of the file, it's probably fine.

https://github.com/llvm/llvm-project/pull/175501