diff --git a/libevmasm/SemanticInformation.cpp b/libevmasm/SemanticInformation.cpp
index cd16185c4..8085bbb67 100644
--- a/libevmasm/SemanticInformation.cpp
+++ b/libevmasm/SemanticInformation.cpp
@@ -268,6 +268,37 @@ SemanticInformation::Effect SemanticInformation::memory(Instruction _instruction
 	}
 }
 
+bool SemanticInformation::readsMemory(Instruction const _instruction)
+{
+	switch (_instruction)
+	{
+	// Instructions that only read from memory
+	case Instruction::CREATE:
+	case Instruction::CREATE2:
+	case Instruction::KECCAK256:
+	case Instruction::MLOAD:
+	case Instruction::MSIZE:
+	case Instruction::RETURN:
+	case Instruction::REVERT:
+	case Instruction::LOG0:
+	case Instruction::LOG1:
+	case Instruction::LOG2:
+	case Instruction::LOG3:
+	case Instruction::LOG4:
+
+	// Instructions that read and write from memory
+	case Instruction::CODECOPY:
+	case Instruction::CALL:
+	case Instruction::CALLCODE:
+	case Instruction::DELEGATECALL:
+	case Instruction::STATICCALL:
+		return true;
+
+	default:
+		return false;
+	}
+}
+
 bool SemanticInformation::movableApartFromEffects(Instruction _instruction)
 {
 	switch (_instruction)
diff --git a/libevmasm/SemanticInformation.h b/libevmasm/SemanticInformation.h
index 8ba2743c4..c78689638 100644
--- a/libevmasm/SemanticInformation.h
+++ b/libevmasm/SemanticInformation.h
@@ -79,6 +79,10 @@ struct SemanticInformation
 	/// msize instruction.
 	static bool canBeRemovedIfNoMSize(Instruction _instruction);
 	static Effect memory(Instruction _instruction);
+	/// Returns `true` if the instruction reads from memory. Different from
+	/// `SemanticInformation::memory(..) == SideEffects::Read` because some builtins read and write
+	/// memory at the same time.
+	static bool readsMemory(Instruction const _instruction);
 	static Effect storage(Instruction _instruction);
 	static Effect otherState(Instruction _instruction);
 	static bool invalidInPureFunctions(Instruction _instruction);