IR: Remove an invalid assertion when replacing resolved operands

This adds back the testcase from r225738, and adds to it.  Looks like we
need both sides for now (the assertion was incorrect both ways, and
although it seemed reasonable (when written correctly) it wasn't
particularly important).

llvm-svn: 225745

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index af110742dd7..d85225561b2 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Instructions.h"
@@ -361,6 +362,32 @@ TEST_F(MDNodeTest, handleChangedOperandRecursion) {
   EXPECT_EQ(N4, N6->getOperand(0));
 }
 
+TEST_F(MDNodeTest, replaceResolvedOperand) {
+  // Check code for replacing one resolved operand with another.  If doing this
+  // directly (via replaceOperandWith()) becomes illegal, change the operand to
+  // a global value that gets RAUW'ed.
+  //
+  // Use a temporary node to keep N from being resolved.
+  std::unique_ptr<MDNodeFwdDecl> Temp(MDNodeFwdDecl::get(Context, None));
+  Metadata *Ops[] = {nullptr, Temp.get()};
+
+  MDNode *Empty = MDTuple::get(Context, {});
+  MDNode *N = MDTuple::get(Context, Ops);
+  EXPECT_EQ(nullptr, N->getOperand(0));
+  ASSERT_FALSE(N->isResolved());
+
+  // Check code for replacing resolved nodes.
+  N->replaceOperandWith(0, Empty);
+  EXPECT_EQ(Empty, N->getOperand(0));
+
+  // Check code for adding another unresolved operand.
+  N->replaceOperandWith(0, Temp.get());
+  EXPECT_EQ(Temp.get(), N->getOperand(0));
+
+  // Remove the references to Temp; required for teardown.
+  Temp->replaceAllUsesWith(nullptr);
+}
+
 typedef MetadataTest MetadataAsValueTest;
 
 TEST_F(MetadataAsValueTest, MDNode) {