diff --git a/lib/Bytecode/Writer/SlotCalculator.cpp b/lib/Bytecode/Writer/SlotCalculator.cpp
index 575dd34dbdf..4a95c7b80f9 100644
--- a/lib/Bytecode/Writer/SlotCalculator.cpp
+++ b/lib/Bytecode/Writer/SlotCalculator.cpp
@@ -691,6 +691,9 @@ int SlotCalculator::getOrCreateSlot(const Value *V) {
   int SlotNo = getSlot(V);        // Check to see if it's already in!
   if (SlotNo != -1) return SlotNo;
 
+  if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
+    assert(GV->getParent() != 0 && "Global not embedded into a module!");
+
   if (!isa<GlobalValue>(V))  // Initializers for globals are handled explicitly
     if (const Constant *C = dyn_cast<Constant>(V)) {
       assert(CompactionNodeMap.empty() &&
diff --git a/lib/Bytecode/Writer/Writer.cpp b/lib/Bytecode/Writer/Writer.cpp
index b54a513b72d..98a4234a410 100644
--- a/lib/Bytecode/Writer/Writer.cpp
+++ b/lib/Bytecode/Writer/Writer.cpp
@@ -295,6 +295,7 @@ void BytecodeWriter::outputConstant(const Constant *CPV) {
   if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
     // FIXME: Encoding of constant exprs could be much more compact!
     assert(CE->getNumOperands() > 0 && "ConstantExpr with 0 operands");
+    assert(CE->getNumOperands() != 1 || CE->getOpcode() == Instruction::Cast);
     output_vbr(1+CE->getNumOperands());   // flags as an expr
     output_vbr(CE->getOpcode());        // flags as an expr