[turbofan] Avoid unnecessary minus zero checks for Float64->Tagged.

src/compiler/representation-change.cc

 // Copyright 2015 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/compiler/representation-change.h"
 
 #include <sstream>
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 209 matching lines @@
       op = simplified()->ChangeInt32ToTagged();
     } else if (output_type->Is(Type::Unsigned32())) {
       op = simplified()->ChangeUint32ToTagged();
     } else {
       return TypeError(node, output_rep, output_type,
                        MachineRepresentation::kTagged);
     }
   } else if (output_rep ==
              MachineRepresentation::kFloat32) {  // float32 -> float64 -> tagged
     node = InsertChangeFloat32ToFloat64(node);
-    // TODO(bmeurer): Pass -0 hint to ChangeFloat64ToTagged.
-    op = simplified()->ChangeFloat64ToTagged();
+    op = simplified()->ChangeFloat64ToTagged(
+        output_type->Maybe(Type::MinusZero())
+            ? CheckForMinusZeroMode::kCheckForMinusZero
+            : CheckForMinusZeroMode::kDontCheckForMinusZero);
   } else if (output_rep == MachineRepresentation::kFloat64) {
     if (output_type->Is(Type::Signed31())) {  // float64 -> int32 -> tagged
       node = InsertChangeFloat64ToInt32(node);
       op = simplified()->ChangeInt31ToTaggedSigned();
     } else if (output_type->Is(
                    Type::Signed32())) {  // float64 -> int32 -> tagged
       node = InsertChangeFloat64ToInt32(node);
       op = simplified()->ChangeInt32ToTagged();
     } else if (output_type->Is(
                    Type::Unsigned32())) {  // float64 -> uint32 -> tagged
       node = InsertChangeFloat64ToUint32(node);
       op = simplified()->ChangeUint32ToTagged();
     } else {
-      // TODO(bmeurer): Pass -0 hint to ChangeFloat64ToTagged.
-      op = simplified()->ChangeFloat64ToTagged();
+      op = simplified()->ChangeFloat64ToTagged(
+          output_type->Maybe(Type::MinusZero())
+              ? CheckForMinusZeroMode::kCheckForMinusZero
+              : CheckForMinusZeroMode::kDontCheckForMinusZero);
     }
   } else {
     return TypeError(node, output_rep, output_type,
                      MachineRepresentation::kTagged);
   }
   return jsgraph()->graph()->NewNode(op, node);
 }
 
 
 Node* RepresentationChanger::GetFloat32RepresentationFor(
@@ skipping 558 matching lines @@
 }
 
 Node* RepresentationChanger::InsertChangeTaggedToFloat64(Node* node) {
   return jsgraph()->graph()->NewNode(simplified()->ChangeTaggedToFloat64(),
                                      node);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8