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

src/register-configuration.cc

Index: src/register-configuration.cc
diff --git a/src/register-configuration.cc b/src/register-configuration.cc
index 1a198ea42cadaf98df240fc6c9b98786031d6c1f..28d0ab2cc50c0e33ed795aece28b4b8fa471118c 100644
--- a/src/register-configuration.cc
+++ b/src/register-configuration.cc
@@ -70,15 +70,12 @@ class ArchDefaultRegisterConfiguration : public RegisterConfiguration {
 #if V8_TARGET_ARCH_IA32
             kMaxAllocatableGeneralRegisterCount,
             kMaxAllocatableDoubleRegisterCount,
-            kMaxAllocatableDoubleRegisterCount,
 #elif V8_TARGET_ARCH_X87
             kMaxAllocatableGeneralRegisterCount,
             compiler == TURBOFAN ? 1 : kMaxAllocatableDoubleRegisterCount,
-            compiler == TURBOFAN ? 1 : kMaxAllocatableDoubleRegisterCount,
 #elif V8_TARGET_ARCH_X64
             kMaxAllocatableGeneralRegisterCount,
             kMaxAllocatableDoubleRegisterCount,
-            kMaxAllocatableDoubleRegisterCount,
 #elif V8_TARGET_ARCH_ARM
             FLAG_enable_embedded_constant_pool
                 ? (kMaxAllocatableGeneralRegisterCount - 1)
@@ -86,27 +83,21 @@ class ArchDefaultRegisterConfiguration : public RegisterConfiguration {
             CpuFeatures::IsSupported(VFP32DREGS)
                 ? kMaxAllocatableDoubleRegisterCount
                 : (ALLOCATABLE_NO_VFP32_DOUBLE_REGISTERS(REGISTER_COUNT) 0),
-            ALLOCATABLE_NO_VFP32_DOUBLE_REGISTERS(REGISTER_COUNT) 0,
 #elif V8_TARGET_ARCH_ARM64
             kMaxAllocatableGeneralRegisterCount,
             kMaxAllocatableDoubleRegisterCount,
-            kMaxAllocatableDoubleRegisterCount,
 #elif V8_TARGET_ARCH_MIPS
             kMaxAllocatableGeneralRegisterCount,
             kMaxAllocatableDoubleRegisterCount,
-            kMaxAllocatableDoubleRegisterCount,
 #elif V8_TARGET_ARCH_MIPS64
             kMaxAllocatableGeneralRegisterCount,
             kMaxAllocatableDoubleRegisterCount,
-            kMaxAllocatableDoubleRegisterCount,
 #elif V8_TARGET_ARCH_PPC
             kMaxAllocatableGeneralRegisterCount,
             kMaxAllocatableDoubleRegisterCount,
-            kMaxAllocatableDoubleRegisterCount,
 #elif V8_TARGET_ARCH_S390
             kMaxAllocatableGeneralRegisterCount,
             kMaxAllocatableDoubleRegisterCount,
-            kMaxAllocatableDoubleRegisterCount,
 #else
 #error Unsupported target architecture.
 #endif
@@ -145,7 +136,6 @@ const RegisterConfiguration* RegisterConfiguration::Turbofan() {
 RegisterConfiguration::RegisterConfiguration(
     int num_general_registers, int num_double_registers,
     int num_allocatable_general_registers, int num_allocatable_double_registers,
-    int num_allocatable_aliased_double_registers,
     const int* allocatable_general_codes, const int* allocatable_double_codes,
     AliasingKind fp_aliasing_kind, const char* const* general_register_names,
     const char* const* float_register_names,
@@ -158,8 +148,6 @@ RegisterConfiguration::RegisterConfiguration(
       num_allocatable_general_registers_(num_allocatable_general_registers),
       num_allocatable_float_registers_(0),
       num_allocatable_double_registers_(num_allocatable_double_registers),
-      num_allocatable_aliased_double_registers_(
-          num_allocatable_aliased_double_registers),
       num_allocatable_simd128_registers_(0),
       allocatable_general_codes_mask_(0),
       allocatable_float_codes_mask_(0),