[wasm] Fixed F32Neg and F64Neg for -0.0.

src/compiler/wasm-compiler.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/access-builder.h"
 #include "src/compiler/change-lowering.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/diamond.h"
 #include "src/compiler/graph.h"
@@ skipping 651 matching lines @@
   const Operator* op;
   MachineOperatorBuilder* m = jsgraph()->machine();
   switch (opcode) {
     case wasm::kExprBoolNot:
       op = m->Word32Equal();
       return graph()->NewNode(op, input, jsgraph()->Int32Constant(0));
     case wasm::kExprF32Abs:
       op = m->Float32Abs();
       break;
     case wasm::kExprF32Neg:
-      op = m->Float32Sub();
-      return graph()->NewNode(op, jsgraph()->Float32Constant(0), input);
+      op = m->Float32Mul();
+      return graph()->NewNode(op, jsgraph()->Float32Constant(-1), input);
     case wasm::kExprF32Sqrt:
       op = m->Float32Sqrt();
       break;
     case wasm::kExprF64Abs:
       op = m->Float64Abs();
       break;
     case wasm::kExprF64Neg:
-      op = m->Float64Sub();
-      return graph()->NewNode(op, jsgraph()->Float64Constant(0), input);
+      op = m->Float64Mul();
+      return graph()->NewNode(op, jsgraph()->Float64Constant(-1), input);
     case wasm::kExprF64Sqrt:
       op = m->Float64Sqrt();
       break;
     case wasm::kExprI32SConvertF64:
       op = m->ChangeFloat64ToInt32();
       break;
     case wasm::kExprI32UConvertF64:
       op = m->ChangeFloat64ToUint32();
       break;
     case wasm::kExprF32ConvertF64:
@@ skipping 1137 matching lines @@
     code->Disassemble(buffer, os);
   }
 #endif
   return code;
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8