Add some debug output to help diagnose PR7689.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109036 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 64c2dfa..f594e0f 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -897,6 +897,9 @@
       Record.push_back(VE.getValueID(BA->getFunction()));
       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
     } else {
+#ifndef NDEBUG
+      C->dump();
+#endif
       llvm_unreachable("Unknown constant!");
     }
     Stream.EmitRecord(Code, Record, AbbrevToUse);