[turbofan] Introduce TruncateTaggedToWord32 simplified operator.

src/code-stub-assembler.cc

 // Copyright 2016 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/code-stub-assembler.h"
 #include "src/code-factory.h"
 
 namespace v8 {
 namespace internal {
 
@@ skipping 708 matching lines @@
         Callable callable = CodeFactory::NonNumberToNumber(isolate());
         var_value.Bind(CallStub(callable, context, value));
         Goto(&loop);
       }
     }
   }
   Bind(&done_loop);
   return var_result.value();
 }
 
-Node* CodeStubAssembler::TruncateFloat64ToInt32(Node* value) {
-  return TruncateFloat64ToInt32JavaScript(value);
-}
-
 Node* CodeStubAssembler::TruncateHeapNumberValueToWord32(Node* object) {
   Node* value = LoadHeapNumberValue(object);
-  return TruncateFloat64ToInt32(value);
+  return TruncateFloat64ToWord32(value);
 }
 
 Node* CodeStubAssembler::ChangeFloat64ToTagged(Node* value) {
-  Node* value32 = TruncateFloat64ToInt32RoundToZero(value);
+  Node* value32 = RoundFloat64ToInt32(value);
   Node* value64 = ChangeInt32ToFloat64(value32);
 
   Label if_valueisint32(this), if_valueisheapnumber(this), if_join(this);
 
   Label if_valueisequal(this), if_valueisnotequal(this);
   Branch(Float64Equal(value, value64), &if_valueisequal, &if_valueisnotequal);
   Bind(&if_valueisequal);
   {
-    Label if_valueiszero(this), if_valueisnotzero(this);
-    Branch(Float64Equal(value, Float64Constant(0.0)), &if_valueiszero,
-           &if_valueisnotzero);
-
-    Bind(&if_valueiszero);
+    GotoUnless(Word32Equal(value32, Int32Constant(0)), &if_valueisint32);
     BranchIfInt32LessThan(Float64ExtractHighWord32(value), Int32Constant(0),
                           &if_valueisheapnumber, &if_valueisint32);
-
-    Bind(&if_valueisnotzero);
-    Goto(&if_valueisint32);
   }
   Bind(&if_valueisnotequal);
   Goto(&if_valueisheapnumber);
 
   Variable var_result(this, MachineRepresentation::kTagged);
   Bind(&if_valueisint32);
   {
     if (Is64()) {
       Node* result = SmiTag(ChangeInt32ToInt64(value32));
       var_result.Bind(result);
@@ skipping 377 matching lines @@
 }
 
 Node* CodeStubAssembler::BitFieldDecode(Node* word32, uint32_t shift,
                                         uint32_t mask) {
   return Word32Shr(Word32And(word32, Int32Constant(mask)),
                    Int32Constant(shift));
 }
 
 }  // namespace internal
 }  // namespace v8