[wasm][revec] Fix control level calculation of LoopExit node

how759 · V8 LUCI CQ · commit b82a91151f0d · 2023-09-05T02:31:24.000Z
LoopExit node is directly connected to the Loop node. In a BFS search this can make the control levels of the nodes after the loop smaller than the control levels of nodes inside loop body. This CL fixes it by ignoring this kind of edge. Bug: v8:12716 Change-Id: I7920f52d409a017e3726349098c36b3be4f4361c Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4837464 Reviewed-by: Tobias Tebbi <tebbi@chromium.org> Commit-Queue: Hao A Xu <hao.a.xu@intel.com> Cr-Commit-Position: refs/heads/main@{#89779}
diff --git a/src/compiler/linear-scheduler.cc b/src/compiler/linear-scheduler.cc
@@ -32,6 +32,9 @@ void LinearScheduler::ComputeControlLevel() {
     for (Edge const edge : node->use_edges()) {
       if (!NodeProperties::IsControlEdge(edge)) continue;
       Node* use = edge.from();
+      if (use->opcode() == IrOpcode::kLoopExit &&
+          node->opcode() == IrOpcode::kLoop)
+        continue;
       if (control_level_.find(use) == control_level_.end() &&
           use->opcode() != IrOpcode::kEnd) {
         SetControlLevel(use, level + 1);
