[C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.

llvm-svn: 206142
diff --git a/llvm/lib/CodeGen/ScoreboardHazardRecognizer.cpp b/llvm/lib/CodeGen/ScoreboardHazardRecognizer.cpp
index 2cd84d6..88d1be6 100644
--- a/llvm/lib/CodeGen/ScoreboardHazardRecognizer.cpp
+++ b/llvm/lib/CodeGen/ScoreboardHazardRecognizer.cpp
@@ -126,7 +126,7 @@
   // free FU's in the scoreboard at the appropriate future cycles.
 
   const MCInstrDesc *MCID = DAG->getInstrDesc(SU);
-  if (MCID == NULL) {
+  if (!MCID) {
     // Don't check hazards for non-machineinstr Nodes.
     return NoHazard;
   }