MIPS64: Implement optimization utilizing signaling NaN for holes in double arrays.

src/mips64/macro-assembler-mips64.h

Index: src/mips64/macro-assembler-mips64.h
diff --git a/src/mips64/macro-assembler-mips64.h b/src/mips64/macro-assembler-mips64.h
index 1e25b334c77cc5b5e4f6cb3a083f149e0d9922fe..d38982f6547d1ca05e1a6c2650fec314e1d373ed 100644
--- a/src/mips64/macro-assembler-mips64.h
+++ b/src/mips64/macro-assembler-mips64.h
@@ -1069,7 +1069,6 @@ class MacroAssembler: public Assembler {
                                    Register elements_reg,
                                    Register scratch1,
                                    Register scratch2,
-                                   Register scratch3,
                                    Label* fail,
                                    int elements_offset = 0);
 
@@ -1116,6 +1115,10 @@ class MacroAssembler: public Assembler {
                        Handle<WeakCell> cell, Handle<Code> success,
                        SmiCheckType smi_check_type);
 
+  // If the value is a NaN, canonicalize the value else, do nothing.
+  void FPUCanonicalizeNaN(const DoubleRegister dst, const DoubleRegister src);
+
+
   // Get value of the weak cell.
   void GetWeakValue(Register value, Handle<WeakCell> cell);