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

src/mips64/lithium-codegen-mips64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/hydrogen-osr.h"
 #include "src/ic/ic.h"
@@ skipping 4455 matching lines @@
     DCHECK((shift_size == 3) || (shift_size == -29));
     if (shift_size == 3) {
       __ dsll(at, ToRegister(instr->key()), 3);
     } else if (shift_size == -29) {
       __ dsra(at, ToRegister(instr->key()), 29);
     }
     __ Daddu(scratch, scratch, at);
   }
 
   if (instr->NeedsCanonicalization()) {
-    Label is_nan;
-    // Check for NaN. All NaNs must be canonicalized.
-    __ BranchF(NULL, &is_nan, eq, value, value);
-    __ Branch(&not_nan);
-
-    // Only load canonical NaN if the comparison above set the overflow.
-    __ bind(&is_nan);
-    __ LoadRoot(at, Heap::kNanValueRootIndex);
-    __ ldc1(double_scratch, FieldMemOperand(at, HeapNumber::kValueOffset));
+    __ FPUCanonicalizeNaN(double_scratch, value);
     __ sdc1(double_scratch, MemOperand(scratch, 0));
-    __ Branch(&done);
+  } else {
+    __ sdc1(value, MemOperand(scratch, 0));
   }
-
-  __ bind(&not_nan);
-  __ sdc1(value, MemOperand(scratch, 0));
-  __ bind(&done);
 }
 
 
 void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
   Register value = ToRegister(instr->value());
   Register elements = ToRegister(instr->elements());
   Register key = instr->key()->IsRegister() ? ToRegister(instr->key())
       : no_reg;
   Register scratch = scratch0();
   Register store_base = scratch;
@@ skipping 1555 matching lines @@
   __ li(at, scope_info);
   __ Push(at, ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal