Take special functions that require literals into account.

1 files changed, 14 insertions, 1 deletions

diff --git a/libyul/optimiser/CommonSubexpressionEliminator.cpp b/libyul/optimiser/CommonSubexpressionEliminator.cpp
index 9b851333..8ce003e7 100644
--- a/libyul/optimiser/CommonSubexpressionEliminator.cpp
+++ b/libyul/optimiser/CommonSubexpressionEliminator.cpp
@@ -25,6 +25,7 @@
 #include <libyul/optimiser/SyntacticalEquality.h>
 #include <libyul/Exceptions.h>
 #include <libyul/AsmData.h>
+#include <libyul/Dialect.h>
 
 using namespace std;
 using namespace dev;
@@ -32,12 +33,24 @@ using namespace yul;
 
 void CommonSubexpressionEliminator::visit(Expression& _e)
 {
+	bool descend = true;
+	// If this is a function call to a function that requires literal arguments,
+	// do not try to simplify there.
+	if (_e.type() == typeid(FunctionCall))
+		if (BuiltinFunction const* builtin = m_dialect.builtin(boost::get<FunctionCall>(_e).functionName.name))
+			if (builtin->literalArguments)
+				// We should not modify function arguments that have to be literals
+				// Note that replacing the function call entirely is fine,
+				// if the function call is movable.
+				descend = false;
+
 	// We visit the inner expression first to first simplify inner expressions,
 	// which hopefully allows more matches.
 	// Note that the DataFlowAnalyzer itself only has code for visiting Statements,
 	// so this basically invokes the AST walker directly and thus post-visiting
 	// is also fine with regards to data flow analysis.
-	DataFlowAnalyzer::visit(_e);
+	if (descend)
+		DataFlowAnalyzer::visit(_e);
 
 	if (_e.type() == typeid(Identifier))
 	{