diff --git a/libevmjit/GasMeter.cpp b/libevmjit/GasMeter.cpp
index 5f6f81e72..a0656ace4 100644
--- a/libevmjit/GasMeter.cpp
+++ b/libevmjit/GasMeter.cpp
@@ -169,11 +169,10 @@ void GasMeter::commitCostBlock(llvm::Value* _additionalCost)
 	assert(m_blockCost == 0);
 }
 
-void GasMeter::checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilder<>& _builder)
+void GasMeter::checkMemory(llvm::Value* _additionalMemoryInWords)
 {
-	// Memory uses other builder, but that can be changes later
-	auto cost = _builder.CreateMul(_additionalMemoryInWords, Constant::get(static_cast<uint64_t>(c_memoryGas)), "memcost");
-	_builder.CreateCall(m_gasCheckFunc, cost);
+	auto cost = m_builder.CreateNUWMul(_additionalMemoryInWords, Constant::get(static_cast<uint64_t>(c_memoryGas)), "memcost");
+	m_builder.CreateCall(m_gasCheckFunc, cost);
 }
 
 }
diff --git a/libevmjit/GasMeter.h b/libevmjit/GasMeter.h
index dcfde92a3..3de227651 100644
--- a/libevmjit/GasMeter.h
+++ b/libevmjit/GasMeter.h
@@ -32,7 +32,7 @@ public:
 	void giveBack(llvm::Value* _gas);
 
 	/// Generate code that checks the cost of additional memory used by program
-	void checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilder<>& _builder);
+	void checkMemory(llvm::Value* _additionalMemoryInWords);
 
 private:
 	/// Cumulative gas cost of a block of instructions
@@ -40,7 +40,7 @@ private:
 	uint64_t m_blockCost = 0;
 
 	llvm::CallInst* m_checkCall = nullptr;
-	llvm::Function* m_gasCheckFunc;
+	llvm::Function* m_gasCheckFunc = nullptr;
 
 	RuntimeManager& m_runtimeManager;
 };
diff --git a/libevmjit/Memory.cpp b/libevmjit/Memory.cpp
index 322c53ee3..beedd9cb9 100644
--- a/libevmjit/Memory.cpp
+++ b/libevmjit/Memory.cpp
@@ -90,7 +90,7 @@ llvm::Function* Memory::createRequireFunc(GasMeter& _gasMeter, RuntimeManager& _
 	sizeRequired = m_builder.CreateMul(wordsRequired, Constant::get(32), "roundedSizeReq");
 	auto words = m_builder.CreateUDiv(currSize, Constant::get(32), "words");	// size is always 32*k
 	auto newWords = m_builder.CreateSub(wordsRequired, words, "addtionalWords");
-	_gasMeter.checkMemory(newWords, m_builder);
+	_gasMeter.checkMemory(newWords);
 	// Resize
 	m_builder.CreateStore(sizeRequired, m_size);
 	auto newData = m_builder.CreateCall2(m_resize, _runtimeManager.getRuntimePtr(), m_size, "newData");