Use side effects of user-defined functions in other optimizer steps.

libyul/optimiser/DeadCodeEliminator.h

@@ -31,12 +31,15 @@ namespace solidity::yul
 {
 struct Dialect;
 struct OptimiserStepContext;
+struct ControlFlowSideEffects;
 
 /**
  * Optimisation stage that removes unreachable code
  *
  * Unreachable code is any code within a block which is preceded by a
- * leave, return, invalid, break, continue, selfdestruct or revert.
+ * leave, return, invalid, break, continue, selfdestruct or revert or
+ * a call to a user-defined function that never returns (either due to
+ * recursion or a call to return / revert / stop).
  *
  * Function definitions are retained as they might be called by earlier
  * code and thus are considered reachable.
@@ -57,9 +60,13 @@ public:
 	void operator()(Block& _block) override;
 
 private:
-	DeadCodeEliminator(Dialect const& _dialect): m_dialect(_dialect) {}
+	DeadCodeEliminator(
+		Dialect const& _dialect,
+		std::map<YulString, ControlFlowSideEffects> const& _sideEffects
+	): m_dialect(_dialect), m_functionSideEffects(_sideEffects) {}
 
 	Dialect const& m_dialect;
+	std::map<YulString, ControlFlowSideEffects> const& m_functionSideEffects;
 };
 
 }