MIPS: Improve register allocation for Lithium representation changes on ARM

src/mips/macro-assembler-mips.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1204 matching lines @@
   // control continues at the label not_power_of_two. If reg is a power of two
   // the register scratch contains the value of (reg - 1) when control falls
   // through.
   void JumpIfNotPowerOfTwoOrZero(Register reg,
                                  Register scratch,
                                  Label* not_power_of_two_or_zero);
 
   // -------------------------------------------------------------------------
   // Smi utilities.
 
-  // Try to convert int32 to smi. If the value is to large, preserve
-  // the original value and jump to not_a_smi. Destroys scratch and
-  // sets flags.
-  // This is only used by crankshaft atm so it is unimplemented on MIPS.
-  void TrySmiTag(Register reg, Label* not_a_smi, Register scratch) {
-    UNIMPLEMENTED_MIPS();
-  }
-
   void SmiTag(Register reg) {
     Addu(reg, reg, reg);
   }
 
   // Test for overflow < 0: use BranchOnOverflow() or BranchOnNoOverflow().
-  void SmiTagCheckOverflow(Register reg, Register overflow) {
-    mov(overflow, reg);  // Save original value.
-    addu(reg, reg, reg);
-    xor_(overflow, overflow, reg);  // Overflow if (value ^ 2 * value) < 0.
-  }
+  void SmiTagCheckOverflow(Register reg, Register overflow);
+  void SmiTagCheckOverflow(Register dst, Register src, Register overflow);
 
   void SmiTag(Register dst, Register src) {
     Addu(dst, src, src);
   }
 
   void SmiUntag(Register reg) {
     sra(reg, reg, kSmiTagSize);
   }
 
   void SmiUntag(Register dst, Register src) {
@@ skipping 216 matching lines @@
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_MIPS_MACRO_ASSEMBLER_MIPS_H_