[llvm] r225745 - IR: Remove an invalid assertion when replacing resolved operands

[Duncan P. N. Exon Smith]

Author: dexonsmith
Date: Mon Jan 12 18:46:34 2015
New Revision: 225745

URL: http://llvm.org/viewvc/llvm-project?rev=225745&view=rev
Log:
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).

Modified:
    llvm/trunk/lib/IR/Metadata.cpp
    llvm/trunk/unittests/IR/MetadataTest.cpp

Modified: llvm/trunk/lib/IR/Metadata.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Metadata.cpp?rev=225745&r1=225744&r2=225745&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Metadata.cpp (original)
+++ llvm/trunk/lib/IR/Metadata.cpp Mon Jan 12 18:46:34 2015
@@ -443,9 +443,11 @@ void UniquableMDNode::resolveAfterOperan
   assert(SubclassData32 != 0 && "Expected unresolved operands");
 
   // Check if an operand was resolved.
-  if (!isOperandUnresolved(Old))
-    assert(isOperandUnresolved(New) && "Operand just became unresolved");
-  else if (!isOperandUnresolved(New))
+  if (!isOperandUnresolved(Old)) {
+    if (isOperandUnresolved(New))
+      // An operand was un-resolved!
+      ++SubclassData32;
+  } else if (!isOperandUnresolved(New))
     decrementUnresolvedOperandCount();
 }
 

Modified: llvm/trunk/unittests/IR/MetadataTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/IR/MetadataTest.cpp?rev=225745&r1=225744&r2=225745&view=diff
==============================================================================
--- llvm/trunk/unittests/IR/MetadataTest.cpp (original)
+++ llvm/trunk/unittests/IR/MetadataTest.cpp Mon Jan 12 18:46:34 2015
@@ -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, handleChangedOperandR
   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) {