Index: lib/CodeGen/AsmPrinter/DwarfUnit.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -463,6 +463,9 @@
       varField = DT;
   }
 
+  assert(forwardingField && "forwarding field must not be NULL");
+  assert(varField && "var field must not be NULL");
+
   // Get the offsets for the forwarding field and the variable field.
   unsigned forwardingFieldOffset = forwardingField->getOffsetInBits() >> 3;
   unsigned varFieldOffset = varField->getOffsetInBits() >> 2;
Index: lib/CodeGen/ScheduleDAGInstrs.cpp
===================================================================
--- lib/CodeGen/ScheduleDAGInstrs.cpp
+++ lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -914,7 +914,8 @@
   for (MachineBasicBlock::iterator MII = RegionEnd, MIE = RegionBegin;
        MII != MIE; --MII) {
     MachineInstr *MI = std::prev(MII);
-    if (MI && DbgMI) {
+
+    if (DbgMI) {
       DbgValues.push_back(std::make_pair(DbgMI, MI));
       DbgMI = nullptr;
     }
Index: lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6465,6 +6465,9 @@
   // assign it now.
   if (unsigned AssignedReg = PhysReg.first) {
     const TargetRegisterClass *RC = PhysReg.second;
+
+    assert(RC && "TargetRegisterClass needs to be not NULL");
+
     if (OpInfo.ConstraintVT == MVT::Other)
       ValueVT = *RC->vt_begin();