[turbofan] Convert Smi to Word64 using zero extension

isheludko · V8 LUCI CQ · commit 45eb42cd398e · 2025-05-28T01:10:33.000-07:00
... when a known type range contains only positive values. Bug: 420637585 Change-Id: I8d9bb3f2fe2e5268e1659bb4ea7bbf97bfb52288 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/6594731 Reviewed-by: Nico Hartmann <nicohartmann@chromium.org> Commit-Queue: Igor Sheludko <ishell@chromium.org> Cr-Commit-Position: refs/heads/main@{#100538}
diff --git a/src/compiler/representation-change.cc b/src/compiler/representation-change.cc
@@ -1394,7 +1394,12 @@ Node* RepresentationChanger::GetWord64RepresentationFor(
     }
   } else if (output_rep == MachineRepresentation::kTaggedSigned) {
     if (output_type.Is(Type::SignedSmall())) {
-      op = simplified()->ChangeTaggedSignedToInt64();
+      if (output_type.IsRange() && output_type.AsRange()->Min() >= 0) {
+        node = InsertChangeTaggedSignedToInt32(node);
+        op = machine()->ChangeUint32ToUint64();
+      } else {
+        op = simplified()->ChangeTaggedSignedToInt64();
+      }
     } else {
       return TypeError(node, output_rep, output_type,
                        MachineRepresentation::kWord64);
