[wasm][bug] Use correct maximum size for loop unrolling

Bug: v8:11298
Change-Id: I064cfda6744f01099f70aab37cfd620afaff1262
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2726505Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73102}

src/compiler/loop-unrolling.h

@@ -28,6 +28,10 @@ V8_INLINE uint32_t unrolling_count_heuristic(uint32_t size, uint32_t depth) {
                   kMaximumUnrollingCount);
 }
 
+V8_INLINE uint32_t maximum_unrollable_size(uint32_t depth) {
+  return (depth + 1) * kMaximumUnnestedSize;
+}
+
 void UnrollLoop(Node* loop_node, ZoneUnorderedSet<Node*>* loop, uint32_t depth,
                 Graph* graph, CommonOperatorBuilder* common, Zone* tmp_zone,
                 SourcePositionTable* source_positions,

src/compiler/pipeline.cc

@@ -1788,8 +1788,7 @@ struct WasmLoopUnrollingPhase {
             loop_info.header, temp_zone,
             // Only discover the loop until its size is the maximum unrolled
             // size for its depth.
-            unrolling_count_heuristic(kMaximumUnnestedSize,
-                                      loop_info.nesting_depth));
+            maximum_unrollable_size(loop_info.nesting_depth));
         UnrollLoop(loop_info.header, loop, loop_info.nesting_depth,
                    data->graph(), data->common(), temp_zone,
                    data->source_positions(), data->node_origins());