Fix PrunedLiveness.empty() to consider the users.

atrick · atrick · commit 8bcb8c6f8bbe · 2023-03-02T10:52:26.000-08:00
diff --git a/include/swift/SIL/PrunedLiveness.h b/include/swift/SIL/PrunedLiveness.h
@@ -484,7 +484,9 @@ class PrunedLiveness {
 
   bool empty() const {
     assert(!liveBlocks.empty() || users.empty());
-    return liveBlocks.empty();
+    // There may be a liveBlock created by initializeDefBlock with no users. The
+    // true test of emptiness is whether there are any users.
+    return users.empty();
   }
 
   void clear() {

Original file line number	Diff line number	Diff line change
`@@ -484,7 +484,9 @@ class PrunedLiveness {`
`484`	`484`
`485`	`485`	`bool empty() const {`
`486`	`486`	`assert(!liveBlocks.empty() \|\| users.empty());`
`487`		`- return liveBlocks.empty();`
	`487`	`+ // There may be a liveBlock created by initializeDefBlock with no users. The`
	`488`	`+ // true test of emptiness is whether there are any users.`
	`489`	`+ return users.empty();`
`488`	`490`	`}`
`489`	`491`
`490`	`492`	`void clear() {`