Work-around weird GCC 4.6 linker issue with SmiTagging template.

src/compiler/change-lowering.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/change-lowering.h"
 
 #include "src/compiler/js-graph.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 24 matching lines @@
 
 Node* ChangeLowering::HeapNumberValueIndexConstant() {
   STATIC_ASSERT(HeapNumber::kValueOffset % kPointerSize == 0);
   const int heap_number_value_offset =
       ((HeapNumber::kValueOffset / kPointerSize) * (machine()->is64() ? 8 : 4));
   return jsgraph()->Int32Constant(heap_number_value_offset - kHeapObjectTag);
 }
 
 
 Node* ChangeLowering::SmiShiftBitsConstant() {
-  const int smi_shift_size = (machine()->is64() ? SmiTagging<8>::kSmiShiftSize
-                                                : SmiTagging<4>::kSmiShiftSize);
+  // TODO(turbofan): Work-around for weird GCC 4.6 linker issue:
+  // src/compiler/change-lowering.cc:46: undefined reference to
+  // `v8::internal::SmiTagging<4u>::kSmiShiftSize'
+  // src/compiler/change-lowering.cc:46: undefined reference to
+  // `v8::internal::SmiTagging<8u>::kSmiShiftSize'
+  STATIC_ASSERT(SmiTagging<4>::kSmiShiftSize == 0);
+  STATIC_ASSERT(SmiTagging<8>::kSmiShiftSize == 31);
+  const int smi_shift_size = machine()->is64() ? 31 : 0;
   return jsgraph()->Int32Constant(smi_shift_size + kSmiTagSize);
 }
 
 
 Reduction ChangeLowering::ChangeBitToBool(Node* val, Node* control) {
   Node* branch = graph()->NewNode(common()->Branch(), val, control);
 
   Node* if_true = graph()->NewNode(common()->IfTrue(), branch);
   Node* true_value = jsgraph()->TrueConstant();
 
@@ skipping 90 matching lines @@
 Graph* ChangeLowering::graph() const { return jsgraph()->graph(); }
 
 
 CommonOperatorBuilder* ChangeLowering::common() const {
   return jsgraph()->common();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8