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

src/compiler/arm/instruction-selector-arm.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/base/bits.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 1055 matching lines @@
 }
 
 
 namespace {
 
 // Shared routine for multiple float compare operations.
 void VisitFloat64Compare(InstructionSelector* selector, Node* node,
                          FlagsContinuation* cont) {
   ArmOperandGenerator g(selector);
   Float64BinopMatcher m(node);
+  InstructionOperand* rhs = m.right().Is(0.0) ? g.UseImmediate(m.right().node())
+                                              : g.UseRegister(m.right().node());
   if (cont->IsBranch()) {
     selector->Emit(cont->Encode(kArmVcmpF64), nullptr,
-                   g.UseRegister(m.left().node()),
-                   g.UseRegister(m.right().node()), g.Label(cont->true_block()),
+                   g.UseRegister(m.left().node()), rhs,
+                   g.Label(cont->true_block()),
                    g.Label(cont->false_block()))->MarkAsControl();
   } else {
     DCHECK(cont->IsSet());
-    selector->Emit(
-        cont->Encode(kArmVcmpF64), g.DefineAsRegister(cont->result()),
-        g.UseRegister(m.left().node()), g.UseRegister(m.right().node()));
+    selector->Emit(cont->Encode(kArmVcmpF64),
+                   g.DefineAsRegister(cont->result()),
+                   g.UseRegister(m.left().node()), rhs);
   }
 }
 
 
 // Shared routine for multiple word compare operations.
 void VisitWordCompare(InstructionSelector* selector, Node* node,
                       InstructionCode opcode, FlagsContinuation* cont) {
   ArmOperandGenerator g(selector);
   Int32BinopMatcher m(node);
   InstructionOperand* inputs[5];
@@ skipping 237 matching lines @@
              MachineOperatorBuilder::kFloat64Ceil |
              MachineOperatorBuilder::kFloat64RoundTruncate |
              MachineOperatorBuilder::kFloat64RoundTiesAway;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8