QmlCompiler: Avoid infinite loop in dead store elimination

We have to mark the required variables also in block 0. And we shouldn't
generate empty blocks.

Fixes: QTBUG-101011
Change-Id: I0dd19f69f45f507cb83e2ddfba3060de48a940b4
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit 88147eb3f621e7d972410698d6edca16493d7c66)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/auto/qml/qmlcppcodegen/data/deadStoreLoop.qml b/tests/auto/qml/qmlcppcodegen/data/deadStoreLoop.qml
new file mode 100644
index 0000000000..f493e4b942
--- /dev/null
+++ b/tests/auto/qml/qmlcppcodegen/data/deadStoreLoop.qml
@@ -0,0 +1,13 @@
+import QtQuick
+import QtQuick.Controls.Basic
+
+Item {
+    Menu {
+        id: m
+    }
+    function c() {
+        while (m.count > 0) {
+            m.removeItem(m.itemAt(0))
+        }
+    }
+}