[turbofan] Allow 0.0 as immediate for floating-point comparison on arm/arm64.

src/compiler/arm64/instruction-selector-arm64.cc

 // Copyright 2014 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/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 1202 matching lines @@
 static void VisitWord64Test(InstructionSelector* selector, Node* node,
                             FlagsContinuation* cont) {
   VisitWordTest(selector, node, kArm64Tst, cont);
 }
 
 
 // Shared routine for multiple float compare operations.
 static void VisitFloat64Compare(InstructionSelector* selector, Node* node,
                                 FlagsContinuation* cont) {
   Arm64OperandGenerator g(selector);
-  Node* left = node->InputAt(0);
-  Node* right = node->InputAt(1);
-  VisitCompare(selector, kArm64Float64Cmp, g.UseRegister(left),
-               g.UseRegister(right), cont);
+  Float64BinopMatcher m(node);
+  if (m.right().Is(0.0)) {
+    VisitCompare(selector, kArm64Float64Cmp, g.UseRegister(m.left().node()),
+                 g.UseImmediate(m.right().node()), cont);
+  } else {
+    VisitCompare(selector, kArm64Float64Cmp, g.UseRegister(m.left().node()),
+                 g.UseRegister(m.right().node()), cont);
+  }
 }
 
 
 void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
                                       BasicBlock* fbranch) {
   OperandGenerator g(this);
   Node* user = branch;
   Node* value = branch->InputAt(0);
 
   FlagsContinuation cont(kNotEqual, tbranch, fbranch);
@@ skipping 285 matching lines @@
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kWord32ShiftIsSafe |
          MachineOperatorBuilder::kInt32DivIsSafe |
          MachineOperatorBuilder::kUint32DivIsSafe;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8