[turbofan] Reduce memory consumption of graph building

test/unittests/compiler/value-numbering-reducer-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits>
 
 #include "src/compiler/graph.h"
 #include "src/compiler/value-numbering-reducer.h"
 #include "test/unittests/test-utils.h"
 
@@ skipping 49 matching lines @@
   Node* n1 = graph()->NewNode(&op);
   EXPECT_FALSE(Reduce(n0).Changed());
   EXPECT_FALSE(Reduce(n1).Changed());
 }
 
 
 TEST_F(ValueNumberingReducerTest, OperatorEqualityNotIdentity) {
   static const size_t kMaxInputCount = 16;
   Node* inputs[kMaxInputCount];
   for (size_t i = 0; i < arraysize(inputs); ++i) {
-    Operator::Opcode opcode = static_cast<Operator::Opcode>(
-        std::numeric_limits<Operator::Opcode>::max() - i);
+    Operator::Opcode opcode =
+        static_cast<Operator::Opcode>(IrOpcode::kLast - i);

[Benedikt Meurer, 2014/10/27 09:29:14]

What is the purpose of this change?

[Michael Starzinger, 2014/10/27 09:34:19]

Is there any particular reason for this change? I actually would like to get rid
of IrOpcode::kLast completely if we can, it's only used in one assertion AFAICT.

     inputs[i] = graph()->NewNode(new (zone()) SimpleOperator(
         opcode, Operator::kEliminatable, 0, 1, "Operator"));
   }
   TRACED_FORRANGE(size_t, input_count, 0, arraysize(inputs)) {
     const SimpleOperator op1(static_cast<Operator::Opcode>(input_count),
                              Operator::kEliminatable,
                              static_cast<int>(input_count), 1, "op");
     Node* n1 = graph()->NewNode(&op1, static_cast<int>(input_count), inputs);
     Reduction r1 = Reduce(n1);
     EXPECT_FALSE(r1.Changed());
 
     const SimpleOperator op2(static_cast<Operator::Opcode>(input_count),
                              Operator::kEliminatable,
                              static_cast<int>(input_count), 1, "op");
     Node* n2 = graph()->NewNode(&op2, static_cast<int>(input_count), inputs);
     Reduction r2 = Reduce(n2);
     EXPECT_TRUE(r2.Changed());
     EXPECT_EQ(n1, r2.replacement());
   }
 }
 
 
 TEST_F(ValueNumberingReducerTest, SubsequentReductionsYieldTheSameNode) {
   static const size_t kMaxInputCount = 16;
   Node* inputs[kMaxInputCount];
   for (size_t i = 0; i < arraysize(inputs); ++i) {
-    Operator::Opcode opcode = static_cast<Operator::Opcode>(
-        std::numeric_limits<Operator::Opcode>::max() - i);
+    Operator::Opcode opcode =
+        static_cast<Operator::Opcode>(IrOpcode::kLast - i);

[Benedikt Meurer, 2014/10/27 09:29:14]

What is the purpose of this change?

     inputs[i] = graph()->NewNode(new (zone()) SimpleOperator(
         opcode, Operator::kEliminatable, 0, 1, "Operator"));
   }
   TRACED_FORRANGE(size_t, input_count, 0, arraysize(inputs)) {
     const SimpleOperator op1(1, Operator::kEliminatable,
                              static_cast<int>(input_count), 1, "op1");
     Node* n = graph()->NewNode(&op1, static_cast<int>(input_count), inputs);
     Reduction r = Reduce(n);
     EXPECT_FALSE(r.Changed());
 
@@ skipping 10 matching lines @@
 
 TEST_F(ValueNumberingReducerTest, WontReplaceNodeWithItself) {
   Node* n = graph()->NewNode(&kOp0);
   EXPECT_FALSE(Reduce(n).Changed());
   EXPECT_FALSE(Reduce(n).Changed());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8