Use getVNInfoBefore() when it makes sense.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144517 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 42e122e..a85639f 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -680,15 +680,14 @@
       // Connect to values live out of predecessors.
       for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
            PE = MBB->pred_end(); PI != PE; ++PI)
-        if (const VNInfo *PVNI =
-              LI->getVNInfoAt(LIS.getMBBEndIdx(*PI).getPrevSlot()))
+        if (const VNInfo *PVNI = LI->getVNInfoBefore(LIS.getMBBEndIdx(*PI)))
           EqClass.join(VNI->id, PVNI->id);
     } else {
       // Normal value defined by an instruction. Check for two-addr redef.
       // FIXME: This could be coincidental. Should we really check for a tied
       // operand constraint?
       // Note that VNI->def may be a use slot for an early clobber def.
-      if (const VNInfo *UVNI = LI->getVNInfoAt(VNI->def.getPrevSlot()))
+      if (const VNInfo *UVNI = LI->getVNInfoBefore(VNI->def))
         EqClass.join(VNI->id, UVNI->id);
     }
   }