Add support to load/store byte fields.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index b4c716768aefac77b0757e0b25ca3a49787b0af7..eeafe57911a015a91784f5b709bcd88ec1936d77 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -2057,7 +2057,9 @@ LInstruction* LChunkBuilder::DoStoreContextSlot(HStoreContextSlot* instr) {
 
 
 LInstruction* LChunkBuilder::DoLoadNamedField(HLoadNamedField* instr) {
-  if (instr->access().IsExternalMemory() && instr->access().offset() == 0) {
+  if (instr->access().IsExternalMemory() &&
+      !instr->access().representation().IsSpecialization() &&

[mvstanton, 2013/10/02 11:13:12]

Could you add a comment to summarize this decision?

[Benedikt Meurer, 2013/10/02 11:48:06]

Done.

+      instr->access().offset() == 0) {
     LOperand* obj = UseRegisterOrConstantAtStart(instr->object());
     return DefineFixed(new(zone()) LLoadNamedField(obj), rax);
   }