[turbofan] Change TruncateFloat64ToUint64 to TryTruncateFloatToUint64.

src/compiler/ppc/instruction-selector-ppc.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/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/ppc/frames-ppc.h"
 
@@ skipping 928 matching lines @@
   }
   VisitRR(this, kPPC_DoubleToInt64, node);
 }
 
 
 void InstructionSelector::VisitTruncateFloat32ToUint64(Node* node) {
   VisitRR(this, kPPC_DoubleToUint64, node);
 }
 
 
-void InstructionSelector::VisitTruncateFloat64ToUint64(Node* node) {
+void InstructionSelector::VisitTryTruncateFloat64ToUint64(Node* node) {
+  if (NodeProperties::FindProjection(node, 1)) {
+    // TODO(ppc): implement the second return value.
+    UNIMPLEMENTED();
+  }
   VisitRR(this, kPPC_DoubleToUint64, node);
 }
 
 
 void InstructionSelector::VisitChangeInt32ToInt64(Node* node) {
   // TODO(mbrandy): inspect input to see if nop is appropriate.
   VisitRR(this, kPPC_ExtendSignWord32, node);
 }
 
 
@@ skipping 739 matching lines @@
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kWord32Popcnt |
          MachineOperatorBuilder::kWord64Popcnt;
   // We omit kWord32ShiftIsSafe as s[rl]w use 0x3f as a mask rather than 0x1f.
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8