[turbofan][x64] Improve code generation for Float64LessThan with Float64Abs.

src/compiler/effect-control-linearizer.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/effect-control-linearizer.h"
 
 #include "src/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/linkage.h"
@@ skipping 895 matching lines @@
   Node* value = node->InputAt(0);
   value = graph()->NewNode(machine()->WordEqual(), value,
                            jsgraph()->TrueConstant());
   return ValueEffectControl(value, effect, control);
 }
 
 EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::LowerTruncateTaggedToBit(Node* node, Node* effect,
                                                   Node* control) {
   Node* value = node->InputAt(0);
-  Node* one = jsgraph()->Int32Constant(1);
   Node* zero = jsgraph()->Int32Constant(0);
   Node* fzero = jsgraph()->Float64Constant(0.0);
 
   // Collect effect/control/value triples.
   int count = 0;
-  Node* values[7];
-  Node* effects[7];
-  Node* controls[6];
+  Node* values[6];
+  Node* effects[6];
+  Node* controls[5];
 
   // Check if {value} is a Smi.
   Node* check_smi = ObjectIsSmi(value);
   Node* branch_smi = graph()->NewNode(common()->Branch(BranchHint::kFalse),
                                       check_smi, control);
 
   // If {value} is a Smi, then we only need to check that it's not zero.
   Node* if_smi = graph()->NewNode(common()->IfTrue(), branch_smi);
   Node* esmi = effect;
   {
@@ skipping 70 matching lines @@
 
   // For HeapNumber {value}, just check that its value is not 0.0, -0.0 or NaN.
   Node* if_heapnumber = graph()->NewNode(common()->IfTrue(), branch_heapnumber);
   Node* eheapnumber = effect;
   {
     // Load the raw value of {value}.
     Node* value_value = eheapnumber = graph()->NewNode(
         simplified()->LoadField(AccessBuilder::ForHeapNumberValue()), value,
         eheapnumber, if_heapnumber);
 
-    // Check if {value} is either less than 0.0 or greater than 0.0.
-    Node* check =
-        graph()->NewNode(machine()->Float64LessThan(), fzero, value_value);
-    Node* branch = graph()->NewNode(common()->Branch(), check, if_heapnumber);
-
-    controls[count] = graph()->NewNode(common()->IfTrue(), branch);
+    // Check if {value} is not one of 0, -0, or NaN.
+    controls[count] = if_heapnumber;
     effects[count] = eheapnumber;
-    values[count] = one;
-    count++;
-
-    controls[count] = graph()->NewNode(common()->IfFalse(), branch);
-    effects[count] = eheapnumber;
-    values[count] =
-        graph()->NewNode(machine()->Float64LessThan(), value_value, fzero);
+    values[count] = graph()->NewNode(
+        machine()->Float64LessThan(), fzero,
+        graph()->NewNode(machine()->Float64Abs(), value_value));
     count++;
   }
   control = graph()->NewNode(common()->IfFalse(), branch_heapnumber);
 
   // The {value} is either a JSReceiver, a Symbol or some Simd128Value. In
   // those cases we can just the undetectable bit on the map, which will only
   // be set for certain JSReceivers, i.e. document.all.
   {
     // Load the {value} map bit field.
     Node* value_map_bitfield = effect = graph()->NewNode(
@@ skipping 2617 matching lines @@
         isolate(), graph()->zone(), callable.descriptor(), 0, flags,
         Operator::kEliminatable);
     to_number_operator_.set(common()->Call(desc));
   }
   return to_number_operator_.get();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8