[turbofan] Prevent storing signalling NaNs into holey double arrays.

src/compiler/machine-operator.h

 // Copyright 2013 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.
 
 #ifndef V8_COMPILER_MACHINE_OPERATOR_H_
 #define V8_COMPILER_MACHINE_OPERATOR_H_
 
 #include "src/base/flags.h"
 #include "src/machine-type.h"
 
@@ skipping 364 matching lines @@
   // Floating point logarithm (double-precision).
   const Operator* Float64Log();
   const Operator* Float64Log1p();
 
   // Floating point bit representation.
   const Operator* Float64ExtractLowWord32();
   const Operator* Float64ExtractHighWord32();
   const Operator* Float64InsertLowWord32();
   const Operator* Float64InsertHighWord32();
 
+  // Change signalling NaN to quiet NaN.
+  // Identity for any input that is not signalling NaN.
+  const Operator* Float64SilenceNaN();
+
   // SIMD operators.
   const Operator* CreateFloat32x4();
   const Operator* Float32x4ExtractLane();
   const Operator* Float32x4ReplaceLane();
   const Operator* Float32x4Abs();
   const Operator* Float32x4Neg();
   const Operator* Float32x4Sqrt();
   const Operator* Float32x4RecipApprox();
   const Operator* Float32x4RecipSqrtApprox();
   const Operator* Float32x4Add();
@@ skipping 252 matching lines @@
 };
 
 
 DEFINE_OPERATORS_FOR_FLAGS(MachineOperatorBuilder::Flags)
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_MACHINE_OPERATOR_H_