Use the "enum hack" to fix the SmiTagging constants.

src/compiler/change-lowering.cc

Index: src/compiler/change-lowering.cc
diff --git a/src/compiler/change-lowering.cc b/src/compiler/change-lowering.cc
index c2805bb0a329b463536b0deef8edadc6fa567d47..e9fd7400d03a6933a37d103c376099cb8067abbe 100644
--- a/src/compiler/change-lowering.cc
+++ b/src/compiler/change-lowering.cc
@@ -50,28 +50,16 @@ Node* ChangeLowering::HeapNumberValueIndexConstant() {
 
 
 Node* ChangeLowering::SmiMaxValueConstant() {
-  // TODO(turbofan): Work-around for weird GCC 4.6 linker issue:
-  // src/compiler/change-lowering.cc:46: undefined reference to
-  // `v8::internal::SmiTagging<4u>::kSmiValueSize'
-  // src/compiler/change-lowering.cc:46: undefined reference to
-  // `v8::internal::SmiTagging<8u>::kSmiValueSize'
-  STATIC_ASSERT(SmiTagging<4>::kSmiValueSize == 31);
-  STATIC_ASSERT(SmiTagging<8>::kSmiValueSize == 32);
-  const int smi_value_size = machine()->is64() ? 32 : 31;
+  const int smi_value_size = machine()->is32() ? SmiTagging<4>::SmiValueSize()
+                                               : SmiTagging<8>::SmiValueSize();
   return jsgraph()->Int32Constant(
       -(static_cast<int>(0xffffffffu << (smi_value_size - 1)) + 1));
 }
 
 
 Node* ChangeLowering::SmiShiftBitsConstant() {
-  // 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;
+  const int smi_shift_size = machine()->is32() ? SmiTagging<4>::SmiShiftSize()
+                                               : SmiTagging<8>::SmiShiftSize();
   return jsgraph()->Int32Constant(smi_shift_size + kSmiTagSize);
 }