livePhysRegs: Pass MBB by reference in addLive{Ins|Outs}(); NFC

The block must no be nullptr for the addLiveIns()/addLiveOuts()
function.

llvm-svn: 268340
diff --git a/llvm/lib/CodeGen/IfConversion.cpp b/llvm/lib/CodeGen/IfConversion.cpp
index ba2fa4c..8ac5a39 100644
--- a/llvm/lib/CodeGen/IfConversion.cpp
+++ b/llvm/lib/CodeGen/IfConversion.cpp
@@ -1136,13 +1136,13 @@
   // Initialize liveins to the first BB. These are potentiall redefined by
   // predicated instructions.
   Redefs.init(TRI);
-  Redefs.addLiveIns(CvtBBI->BB);
-  Redefs.addLiveIns(NextBBI->BB);
+  Redefs.addLiveIns(*CvtBBI->BB);
+  Redefs.addLiveIns(*NextBBI->BB);
 
   // Compute a set of registers which must not be killed by instructions in
   // BB1: This is everything live-in to BB2.
   DontKill.init(TRI);
-  DontKill.addLiveIns(NextBBI->BB);
+  DontKill.addLiveIns(*NextBBI->BB);
 
   if (CvtBBI->BB->pred_size() > 1) {
     BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
@@ -1241,8 +1241,8 @@
   // Initialize liveins to the first BB. These are potentially redefined by
   // predicated instructions.
   Redefs.init(TRI);
-  Redefs.addLiveIns(CvtBBI->BB);
-  Redefs.addLiveIns(NextBBI->BB);
+  Redefs.addLiveIns(*CvtBBI->BB);
+  Redefs.addLiveIns(*NextBBI->BB);
 
   DontKill.clear();
 
@@ -1396,7 +1396,7 @@
   // Initialize liveins to the first BB. These are potentially redefined by
   // predicated instructions.
   Redefs.init(TRI);
-  Redefs.addLiveIns(BBI1->BB);
+  Redefs.addLiveIns(*BBI1->BB);
 
   // Remove the duplicated instructions at the beginnings of both paths.
   // Skip dbg_value instructions