[X86] Add a debug print of the node in the default case for unhandled opcodes in ReplaceNodeResults.

This should be unreachable, but bugs can make it reachable. This
adds a debug print so we can see the bad node in the output when
the llvm_unreachable triggers.

llvm-svn: 364091

Author: topperc

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -27262,6 +27262,10 @@ void X86TargetLowering::ReplaceNodeResults(SDNode *N,
   SDLoc dl(N);
   switch (N->getOpcode()) {
   default:
+#ifndef NDEBUG
+    dbgs() << "ReplaceNodeResults: ";
+    N->dump(&DAG);
+#endif
     llvm_unreachable("Do not know how to custom type legalize this operation!");
   case ISD::CTPOP: {
     assert(N->getValueType(0) == MVT::i64 && "Unexpected VT!");