MIPS64: Improve UInt32 to Double conversion.

src/crankshaft/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/crankshaft/mips64/lithium-codegen-mips64.h"
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/crankshaft/hydrogen-osr.h"
 #include "src/crankshaft/mips64/lithium-gap-resolver-mips64.h"
@@ skipping 4718 matching lines @@
   __ cvt_d_w(ToDoubleRegister(output), single_scratch);
 }
 
 
 void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
   LOperand* input = instr->value();
   LOperand* output = instr->result();
 
   FPURegister dbl_scratch = double_scratch0();
   __ mtc1(ToRegister(input), dbl_scratch);
-  __ Cvt_d_uw(ToDoubleRegister(output), dbl_scratch, f22);  // TODO(plind): f22?
+  __ Cvt_d_uw(ToDoubleRegister(output), dbl_scratch);
 }
 
 
 void LCodeGen::DoNumberTagU(LNumberTagU* instr) {
   class DeferredNumberTagU final : public LDeferredCode {
    public:
     DeferredNumberTagU(LCodeGen* codegen, LNumberTagU* instr)
         : LDeferredCode(codegen), instr_(instr) { }
     void Generate() override {
       codegen()->DoDeferredNumberTagIU(instr_,
@@ skipping 36 matching lines @@
     // disagree. Try to allocate a heap number in new space and store
     // the value in there. If that fails, call the runtime system.
     if (dst.is(src)) {
       __ SmiUntag(src, dst);
       __ Xor(src, src, Operand(0x80000000));
     }
     __ mtc1(src, dbl_scratch);
     __ cvt_d_w(dbl_scratch, dbl_scratch);
   } else {
     __ mtc1(src, dbl_scratch);
-    __ Cvt_d_uw(dbl_scratch, dbl_scratch, f22);
+    __ Cvt_d_uw(dbl_scratch, dbl_scratch);
   }
 
   if (FLAG_inline_new) {
     __ LoadRoot(tmp3, Heap::kHeapNumberMapRootIndex);
     __ AllocateHeapNumber(dst, tmp1, tmp2, tmp3, &slow, TAG_RESULT);
     __ Branch(&done);
   }
 
   // Slow case: Call the runtime system to do the number allocation.
   __ bind(&slow);
@@ skipping 1206 matching lines @@
   __ Push(at, ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8