diff --git a/Makefile b/Makefile
index b1853f77a..61eac585d 100644
--- a/Makefile
+++ b/Makefile
@@ -780,6 +780,10 @@ check-git-abc:
 		echo "Run 'git submodule update' to check out the correct version."; \
 		echo "Note: If testing a different version of abc, call `git commit abc` in the Yosys source directory to update the expected commit."; \
 		exit 1; \
+	elif git -C "$(YOSYS_SRC)" submodule status abc 2>/dev/null | grep -q '^U'; then \
+		echo "'abc' submodule has merge conflicts."; \
+		echo "Please resolve merge conflicts before continuing."; \
+		exit 1; \
 	elif [ -f "$(YOSYS_SRC)/abc/.gitcommit" ] && grep -q '\$$Format:%[hH]\$$' "$(YOSYS_SRC)/abc/.gitcommit"; then \
 		echo "Error: 'abc' is not configured as a git submodule."; \
 		echo "To resolve this:"; \