[Turbofan] Add concept of FP register aliasing on ARM 32.

test/unittests/register-configuration-unittest.cc

 // Copyright 2016 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 "src/register-configuration.h"
 #include "testing/gtest-support.h"
 
 namespace v8 {
 namespace internal {
 
 const MachineRepresentation kFloat32 = MachineRepresentation::kFloat32;
 const MachineRepresentation kFloat64 = MachineRepresentation::kFloat64;
 const MachineRepresentation kSimd128 = MachineRepresentation::kSimd128;
 
 class RegisterConfigurationUnitTest : public ::testing::Test {
  public:
   RegisterConfigurationUnitTest() {}
   virtual ~RegisterConfigurationUnitTest() {}
-
- private:
 };
 
 TEST_F(RegisterConfigurationUnitTest, BasicProperties) {
   const int kNumGeneralRegs = 3;
   const int kNumDoubleRegs = 4;
   const int kNumAllocatableGeneralRegs = 2;
   const int kNumAllocatableDoubleRegs = 2;
   int general_codes[kNumAllocatableGeneralRegs] = {1, 2};
   int double_codes[kNumAllocatableDoubleRegs] = {2, 3};
 
   RegisterConfiguration test(
       kNumGeneralRegs, kNumDoubleRegs, kNumAllocatableGeneralRegs,
-      kNumAllocatableDoubleRegs, kNumAllocatableDoubleRegs, general_codes,
-      double_codes, RegisterConfiguration::OVERLAP, nullptr, nullptr, nullptr,
-      nullptr);
+      kNumAllocatableDoubleRegs, general_codes, double_codes,
+      RegisterConfiguration::OVERLAP, nullptr, nullptr, nullptr, nullptr);
 
   EXPECT_EQ(test.num_general_registers(), kNumGeneralRegs);
   EXPECT_EQ(test.num_double_registers(), kNumDoubleRegs);
   EXPECT_EQ(test.num_allocatable_general_registers(),
             kNumAllocatableGeneralRegs);
   EXPECT_EQ(test.num_allocatable_double_registers(), kNumAllocatableDoubleRegs);
   EXPECT_EQ(test.num_allocatable_float_registers(), kNumAllocatableDoubleRegs);
   EXPECT_EQ(test.num_allocatable_simd128_registers(),
             kNumAllocatableDoubleRegs);
 
@@ skipping 14 matching lines @@
 TEST_F(RegisterConfigurationUnitTest, CombineAliasing) {
   const int kNumGeneralRegs = 3;
   const int kNumDoubleRegs = 4;
   const int kNumAllocatableGeneralRegs = 2;
   const int kNumAllocatableDoubleRegs = 3;
   int general_codes[] = {1, 2};
   int double_codes[] = {2, 3, 16};  // reg 16 should not alias registers 32, 33.
 
   RegisterConfiguration test(
       kNumGeneralRegs, kNumDoubleRegs, kNumAllocatableGeneralRegs,
-      kNumAllocatableDoubleRegs, kNumAllocatableDoubleRegs, general_codes,
-      double_codes, RegisterConfiguration::COMBINE, nullptr, nullptr, nullptr,
-      nullptr);
+      kNumAllocatableDoubleRegs, general_codes, double_codes,
+      RegisterConfiguration::COMBINE, nullptr, nullptr, nullptr, nullptr);
 
   // There are 3 allocatable double regs, but only 2 can alias float regs.
   EXPECT_EQ(test.num_allocatable_float_registers(), 4);
 
   // Test that float registers combine in pairs to form double registers.
   EXPECT_EQ(test.GetAllocatableFloatCode(0), double_codes[0] * 2);
   EXPECT_EQ(test.GetAllocatableFloatCode(1), double_codes[0] * 2 + 1);
   EXPECT_EQ(test.GetAllocatableFloatCode(2), double_codes[1] * 2);
   EXPECT_EQ(test.GetAllocatableFloatCode(3), double_codes[1] * 2 + 1);
 
@@ skipping 67 matching lines @@
   EXPECT_EQ(alias_base_index, 4);
   // High numbered double and simd regs don't alias nonexistent float registers.
   EXPECT_EQ(
       test.GetAliases(kFloat64, RegisterConfiguration::kMaxFPRegisters / 2,
                       kFloat32, &alias_base_index),
       0);
   EXPECT_EQ(
       test.GetAliases(kFloat64, RegisterConfiguration::kMaxFPRegisters / 2 + 1,
                       kFloat32, &alias_base_index),
       0);
-  EXPECT_EQ(test.GetAliases(kFloat64, RegisterConfiguration::kMaxFPRegisters,
-                            kFloat32, &alias_base_index),
-            0);
+  EXPECT_EQ(
+      test.GetAliases(kFloat64, RegisterConfiguration::kMaxFPRegisters - 1,
+                      kFloat32, &alias_base_index),
+      0);
 }
 
 }  // namespace internal
 }  // namespace v8