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diff --git a/src/ir/ordering.h b/src/ir/ordering.h
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+++ b/src/ir/ordering.h
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+/*
+ * Copyright 2021 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef wasm_ir_reorderer_h
+#define wasm_ir_reorderer_h
+
+#include <ir/effects.h>
+#include <wasm-builder.h>
+
+namespace wasm {
+
+//
+// Given two expressions that appear in a specific order - first and then
+// second - this helper can create a sequence in which we return the value of
+// the first. If the two expressions can be reordered, this simply returns
+//
+//   (second, first)
+//
+// If side effects prevent that, it will use a local to save the value of the
+// first, and return it at the end,
+//
+//   (temp = first, second, temp)
+//
+Expression* getResultOfFirst(Expression* first,
+                             Expression* second,
+                             Function* func,
+                             Module* wasm,
+                             const PassOptions& passOptions) {
+  assert(first->type.isConcrete());
+
+  Builder builder(*wasm);
+
+  if (EffectAnalyzer::canReorder(passOptions, wasm->features, first, second)) {
+    return builder.makeSequence(second, first);
+  }
+
+  auto type = first->type;
+  auto index = Builder::addVar(func, type);
+  return builder.makeBlock({builder.makeLocalSet(index, first),
+                            second,
+                            builder.makeLocalGet(index, type)});
+}
+
+} // namespace wasm
+
+#endif // wasm_ir_reorderer_h