Add the concept of FloatRegister for all platforms.

src/ia32/assembler-ia32.h

Index: src/ia32/assembler-ia32.h
diff --git a/src/ia32/assembler-ia32.h b/src/ia32/assembler-ia32.h
index 5313e6cfb4a5aa2e1aecef9410436d288fe4ca3c..8c72105fa51942e117c707d8243dd42fc28fefee 100644
--- a/src/ia32/assembler-ia32.h
+++ b/src/ia32/assembler-ia32.h
@@ -74,6 +74,9 @@ namespace internal {
   V(xmm6)                   \
   V(xmm7)
 
+#define FLOAT_REGISTERS DOUBLE_REGISTERS
+#define SIMD_REGISTERS DOUBLE_REGISTERS
+
 #define ALLOCATABLE_DOUBLE_REGISTERS(V) \
   V(xmm1)                               \
   V(xmm2)                               \
@@ -146,8 +149,7 @@ GENERAL_REGISTERS(DECLARE_REGISTER)
 #undef DECLARE_REGISTER
 const Register no_reg = {Register::kCode_no_reg};
 
-
-struct DoubleRegister {
+struct XMMRegister {
   enum Code {
 #define REGISTER_CODE(R) kCode_##R,
     DOUBLE_REGISTERS(REGISTER_CODE)
@@ -158,8 +160,8 @@ struct DoubleRegister {
 
   static const int kMaxNumRegisters = Code::kAfterLast;
 
-  static DoubleRegister from_code(int code) {
-    DoubleRegister result = {code};
+  static XMMRegister from_code(int code) {
+    XMMRegister result = {code};
     return result;
   }
 
@@ -171,23 +173,25 @@ struct DoubleRegister {
     return reg_code;
   }
 
-  bool is(DoubleRegister reg) const { return reg_code == reg.reg_code; }
+  bool is(XMMRegister reg) const { return reg_code == reg.reg_code; }
 
   const char* ToString();
 
   int reg_code;
 };
 
+typedef XMMRegister FloatRegister;
+
+typedef XMMRegister DoubleRegister;
+
+typedef XMMRegister Simd128Register;
+
 #define DECLARE_REGISTER(R) \
   const DoubleRegister R = {DoubleRegister::kCode_##R};
 DOUBLE_REGISTERS(DECLARE_REGISTER)
 #undef DECLARE_REGISTER
 const DoubleRegister no_double_reg = {DoubleRegister::kCode_no_reg};
 
-typedef DoubleRegister Simd128Register;
-
-typedef DoubleRegister XMMRegister;
-
 enum Condition {
   // any value < 0 is considered no_condition
   no_condition  = -1,