IfConversion: Try to unbreak the MSVC build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192487 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 9de2d25..a816e5e 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -1314,7 +1314,7 @@
   // can compute this set by simulating liveness backwards from the end of BB2.
   LiveRegUnits DontKill;
   for (MachineBasicBlock::reverse_instr_iterator I = BBI2->BB->rbegin(),
-       E = MachineBasicBlock::reverse_iterator(DI2); I != E; ++I) {
+       E = MachineBasicBlock::reverse_instr_iterator(&*DI2); I != E; ++I) {
     DontKill.StepBackward(*I, *TRI);
   }