Index: lib/Analysis/LoopInfo.cpp
===================================================================
--- lib/Analysis/LoopInfo.cpp
+++ lib/Analysis/LoopInfo.cpp
@@ -512,6 +512,8 @@
 /// For subloop blocks, simply update SubloopParents and return NULL.
 Loop *UnloopUpdater::getNearestLoop(BasicBlock *BB, Loop *BBLoop) {
 
+  assert(Unloop && "Unloop cannot be NULL");
+
   // Initially for blocks directly contained by Unloop, NearLoop == Unloop and
   // is considered uninitialized.
   Loop *NearLoop = BBLoop;
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/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6450,6 +6450,9 @@
   // 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();
 
Index: lib/MC/MCParser/AsmParser.cpp
===================================================================
--- lib/MC/MCParser/AsmParser.cpp
+++ lib/MC/MCParser/AsmParser.cpp
@@ -659,7 +659,7 @@
   // section and generate a .file directive.
   if (getContext().getGenDwarfForAssembly()) {
     MCSection *Sec = getStreamer().getCurrentSection().first;
-    if (!Sec->getBeginSymbol()) {
+    if (Sec && !Sec->getBeginSymbol()) {
       MCSymbol *SectionStartSym = getContext().createTempSymbol();
       getStreamer().EmitLabel(SectionStartSym);
       Sec->setBeginSymbol(SectionStartSym);
Index: lib/Target/Hexagon/HexagonInstrInfo.cpp
===================================================================
--- lib/Target/Hexagon/HexagonInstrInfo.cpp
+++ lib/Target/Hexagon/HexagonInstrInfo.cpp
@@ -1301,7 +1301,7 @@
 
   // Keep a flag for upto 4 operands in the instructions, to indicate if
   // that operand has been constant extended.
-  bool OpCExtended[4];
+  bool OpCExtended[4] = {false};
   if (NumOperands > 4)
     NumOperands = 4;
 
Index: lib/Target/NVPTX/NVPTXInstrInfo.cpp
===================================================================
--- lib/Target/NVPTX/NVPTXInstrInfo.cpp
+++ lib/Target/NVPTX/NVPTXInstrInfo.cpp
@@ -179,7 +179,7 @@
     return true;
 
   // If the block ends with NVPTX::GOTO and NVPTX:CBranch, handle it.
-  if (SecondLastInst->getOpcode() == NVPTX::CBranch &&
+  if (SecondLastInst && SecondLastInst->getOpcode() == NVPTX::CBranch &&
       LastInst->getOpcode() == NVPTX::GOTO) {
     TBB = SecondLastInst->getOperand(1).getMBB();
     Cond.push_back(SecondLastInst->getOperand(0));
@@ -189,7 +189,7 @@
 
   // If the block ends with two NVPTX:GOTOs, handle it.  The second one is not
   // executed, so remove it.
-  if (SecondLastInst->getOpcode() == NVPTX::GOTO &&
+  if (SecondLastInst && SecondLastInst->getOpcode() == NVPTX::GOTO &&
       LastInst->getOpcode() == NVPTX::GOTO) {
     TBB = SecondLastInst->getOperand(0).getMBB();
     I = LastInst;
Index: lib/Target/TargetRecip.cpp
===================================================================
--- lib/Target/TargetRecip.cpp
+++ lib/Target/TargetRecip.cpp
@@ -72,7 +72,7 @@
   // Look for an optional setting of the number of refinement steps needed
   // for this type of reciprocal operation.
   size_t RefPos;
-  uint8_t RefSteps;
+  uint8_t RefSteps = 0;
   StringRef RefStepString;
   if (parseRefinementStep(ArgSub, RefPos, RefSteps)) {
     // Split the string for further processing.
@@ -121,7 +121,7 @@
       Val = Val.substr(1);
     
     size_t RefPos;
-    uint8_t RefSteps;
+    uint8_t RefSteps = 0;
     StringRef RefStepString;
     if (parseRefinementStep(Val, RefPos, RefSteps)) {
       // Split the string for further processing.
Index: lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -1247,6 +1247,8 @@
   if (StoreBB == DestBB || OtherBB == DestBB)
     return false;
 
+  assert(OtherBB && "BasicBlock needs to be not NULL");
+
   // Verify that the other block ends in a branch and is not otherwise empty.
   BasicBlock::iterator BBI(OtherBB->getTerminator());
   BranchInst *OtherBr = dyn_cast<BranchInst>(BBI);
Index: lib/Transforms/Scalar/ConstantHoisting.cpp
===================================================================
--- lib/Transforms/Scalar/ConstantHoisting.cpp
+++ lib/Transforms/Scalar/ConstantHoisting.cpp
@@ -240,6 +240,7 @@
 Instruction *ConstantHoisting::
 findConstantInsertionPoint(const ConstantInfo &ConstInfo) const {
   assert(!ConstInfo.RebasedConstants.empty() && "Invalid constant info entry.");
+  assert(Entry && "Entry basic block cannot be NULL");
   // Collect all basic blocks.
   SmallPtrSet<BasicBlock *, 8> BBs;
   for (auto const &RCI : ConstInfo.RebasedConstants)
Index: lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
===================================================================
--- lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
+++ lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
@@ -1007,6 +1007,7 @@
       auto *BaseIE = cast<InsertElementInst>(State.getBase());
       auto *BdvIE = cast<InsertElementInst>(BDV);
       auto UpdateOperand = [&](int OperandIdx) {
+        assert(BaseIE && "base InsertElementInst must not be NULL");
         Value *InVal = BdvIE->getOperand(OperandIdx);
         Value *Base = getBaseForInput(InVal, BaseIE);
         BaseIE->setOperand(OperandIdx, Base);
Index: lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -2704,6 +2704,7 @@
   // instructions into different buckets based on the insert lane.
   SmallVector<Instruction *, 16> Visited;
   for (auto I = CSEWorkList.begin(), E = CSEWorkList.end(); I != E; ++I) {
+    assert(I && "Worklist cannot be NULL");
     assert((I == CSEWorkList.begin() || !DT->dominates(*I, *std::prev(I))) &&
            "Worklist not sorted properly!");
     BasicBlock *BB = (*I)->getBlock();
Index: tools/dsymutil/DwarfLinker.cpp
===================================================================
--- tools/dsymutil/DwarfLinker.cpp
+++ tools/dsymutil/DwarfLinker.cpp
@@ -2448,6 +2448,8 @@
   Attr = Loc ? static_cast<DIEValueList *>(Loc)
              : static_cast<DIEValueList *>(Block);
 
+  assert(Attr && "DIEValue list needs to be not NULL");
+
   if (Loc)
     Value = DIEValue(dwarf::Attribute(AttrSpec.Attr),
                      dwarf::Form(AttrSpec.Form), Loc);