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diff --git a/src/ir/drop.h b/src/ir/drop.h
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+/*
+ * Copyright 2022 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_drop_h
+#define wasm_ir_drop_h
+
+#include "ir/effects.h"
+#include "ir/iteration.h"
+#include "wasm-builder.h"
+#include "wasm.h"
+
+namespace wasm {
+
+// Given an expression, returns a new expression that drops the given
+// expression's children that cannot be removed outright due to their side
+// effects. This is useful if we know the node is not needed but may need to
+// keep the children around; this utility will automatically remove any children
+// we do not actually need to keep, based on their effects.
+//
+// The caller must also pass in a last item to append to the output (which is
+// typically what the original expression is replaced with).
+Expression* getDroppedChildrenAndAppend(Expression* curr,
+                                        Module& wasm,
+                                        const PassOptions& options,
+                                        Expression* last) {
+  Builder builder(wasm);
+  std::vector<Expression*> contents;
+  for (auto* child : ChildIterator(curr)) {
+    if (!EffectAnalyzer(options, wasm, child).hasUnremovableSideEffects()) {
+      continue;
+    }
+    if (child->type.isConcrete()) {
+      contents.push_back(builder.makeDrop(child));
+    } else {
+      // The child is unreachable, or none (none is possible as a child of a
+      // block or loop, etc.); in both cases we do not need a drop.
+      contents.push_back(child);
+    }
+  }
+  contents.push_back(last);
+  if (contents.size() == 1) {
+    return contents[0];
+  }
+  return builder.makeBlock(contents);
+}
+
+} // namespace wasm
+
+#endif // wasm_ir_drop_h