MIPS: Optimise Math.floor(x/y) to use integer division for MIPS.

src/mips/lithium-codegen-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 359 matching lines @@
                                        Handle<String> name,
                                        LEnvironment* env);
 
   // Emits optimized code to deep-copy the contents of statically known
   // object graphs (e.g. object literal boilerplate).
   void EmitDeepCopy(Handle<JSObject> object,
                     Register result,
                     Register source,
                     int* offset);
 
+  // Emit optimized code for integer division.
+  // Inputs are signed.
+  // All registers are clobbered.
+  // If 'remainder' is no_reg, it is not computed.
+  void EmitSignedIntegerDivisionByConstant(Register result,
+                                           Register dividend,
+                                           int32_t divisor,
+                                           Register remainder,
+                                           Register scratch,
+                                           LEnvironment* environment);
+
   struct JumpTableEntry {
     inline JumpTableEntry(Address entry, bool frame, bool is_lazy)
         : label(),
           address(entry),
           needs_frame(frame),
           is_lazy_deopt(is_lazy) { }
     Label label;
     Address address;
     bool needs_frame;
     bool is_lazy_deopt;
@@ skipping 110 matching lines @@
   LCodeGen* codegen_;
   Label entry_;
   Label exit_;
   Label* external_exit_;
   int instruction_index_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_MIPS_LITHIUM_CODEGEN_MIPS_H_