MIPS:[turbofan] Use Nor instruction for bit negation instead of xori.

test/unittests/compiler/mips/instruction-selector-mips-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 "test/unittests/compiler/instruction-selector-unittest.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
@@ skipping 344 matching lines @@
   EXPECT_EQ(dpi.arch_opcode, s[0]->arch_opcode());
   EXPECT_EQ(2U, s[0]->InputCount());
   EXPECT_EQ(1U, s[0]->OutputCount());
 }
 
 
 INSTANTIATE_TEST_CASE_P(InstructionSelectorTest, InstructionSelectorLogicalTest,
                         ::testing::ValuesIn(kLogicalInstructions));
 
 
+TEST_F(InstructionSelectorTest, Word32XorMinusOneWithParameter) {
+  {
+    StreamBuilder m(this, kMachInt32, kMachInt32);
+    m.Return(m.Word32Xor(m.Parameter(0), m.Int32Constant(-1)));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kMipsNor, s[0]->arch_opcode());
+    EXPECT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(1U, s[0]->OutputCount());
+  }
+  {
+    StreamBuilder m(this, kMachInt32, kMachInt32);
+    m.Return(m.Word32Xor(m.Int32Constant(-1), m.Parameter(0)));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kMipsNor, s[0]->arch_opcode());
+    EXPECT_EQ(2U, s[0]->InputCount());
+    EXPECT_EQ(1U, s[0]->OutputCount());
+  }
+}
+
+
 TEST_F(InstructionSelectorTest, Word32XorMinusOneWithWord32Or) {
   {
     StreamBuilder m(this, kMachInt32, kMachInt32);
     m.Return(m.Word32Xor(m.Word32Or(m.Parameter(0), m.Parameter(0)),
                          m.Int32Constant(-1)));
     Stream s = m.Build();
     ASSERT_EQ(1U, s.size());
     EXPECT_EQ(kMipsNor, s[0]->arch_opcode());
     EXPECT_EQ(2U, s[0]->InputCount());
     EXPECT_EQ(1U, s[0]->OutputCount());
@@ skipping 634 matching lines @@
   EXPECT_EQ(kMipsFloat64Min, s[0]->arch_opcode());
   ASSERT_EQ(2U, s[0]->InputCount());
   ASSERT_EQ(1U, s[0]->OutputCount());
   EXPECT_EQ(s.ToVreg(n), s.ToVreg(s[0]->Output()));
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8