From 1ff0e1a58a350c03f59053a584d2e4b76a5a1b80 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Marcelina=20Ko=C5=9Bcielnicka?= <mwk@0x04.net>
Date: Mon, 13 Jun 2022 12:22:59 +0200
Subject: [PATCH] opt_ffinv: Fix use after free.

---
 passes/opt/opt_ffinv.cc | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/passes/opt/opt_ffinv.cc b/passes/opt/opt_ffinv.cc
index fe5b59fa5..5d989dafd 100644
--- a/passes/opt/opt_ffinv.cc
+++ b/passes/opt/opt_ffinv.cc
@@ -201,10 +201,13 @@ struct OptFfInvWorker
 	{
 		log("Discovering LUTs.\n");
 
-		for (Cell *cell : module->selected_cells()) {
-			if (!RTLIL::builtin_ff_cell_types().count(cell->type))
-				continue;
+		std::vector<Cell *> ffs;
+
+		for (Cell *cell : module->selected_cells())
+			if (RTLIL::builtin_ff_cell_types().count(cell->type))
+				ffs.push_back(cell);
 
+		for (Cell *cell : ffs) {
 			FfData ff(&initvals, cell);
 			if (ff.has_sr)
 				continue;
-- 
2.30.2