1 files changed, 43 insertions, 0 deletions
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
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+++ b/src/passes/OptimizeInstructions.cpp
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+/*
+ * Copyright 2016 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.
+ */
+
+//
+// Optimize combinations of instructions
+//
+
+#include <algorithm>
+
+#include <wasm.h>
+#include <pass.h>
+
+namespace wasm {
+
+struct OptimizeInstructions : public WalkerPass<WasmWalker<OptimizeInstructions>> {
+  void visitIf(If* curr) {
+    // flip branches to get rid of an i32.eqz
+    if (curr->ifFalse) {
+      auto condition = curr->condition->dyn_cast<Unary>();
+      if (condition && condition->op == EqZ && condition->value->type == i32) {
+        curr->condition = condition->value;
+        std::swap(curr->ifTrue, curr->ifFalse);
+      }
+    }
+  }
+};
+
+static RegisterPass<OptimizeInstructions> registerPass("optimize-instructions", "optimizes instruction combinations");
+
+} // namespace wasm