1 // Copyright 2014 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef V8_COMPILER_PHI_REDUCER_H_
6 #define V8_COMPILER_PHI_REDUCER_H_
8 #include "src/compiler/generic-node-inl.h"
9 #include "src/compiler/graph-reducer.h"
15 // Replaces redundant phis if all the inputs are the same or the phi itself.
16 class PhiReducer FINAL : public Reducer {
18 virtual Reduction Reduce(Node* node) OVERRIDE {
19 if (node->opcode() != IrOpcode::kPhi &&
20 node->opcode() != IrOpcode::kEffectPhi)
23 int n = node->op()->InputCount();
24 if (n == 1) return Replace(node->InputAt(0));
26 Node* replacement = NULL;
27 Node::Inputs inputs = node->inputs();
28 for (InputIter it = inputs.begin(); n > 0; --n, ++it) {
30 if (input != node && input != replacement) {
31 if (replacement != NULL) return NoChange();
35 DCHECK_NE(node, replacement);
36 return Replace(replacement);
41 } // namespace v8::internal::compiler
43 #endif // V8_COMPILER_PHI_REDUCER_H_