Remove the redundant load on every context lookup.

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1896 matching lines @@
     __ cmp(cell_operand, Factory::the_hole_value());
     DeoptimizeIf(equal, instr->environment());
   }
 
   // Store the value.
   __ mov(cell_operand, value);
 }
 
 
 void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
-  Register context = ToRegister(instr->InputAt(0));
+  Register context = ToRegister(instr->context());
   Register result = ToRegister(instr->result());
-  __ mov(result,
-         Operand(context, Context::SlotOffset(Context::FCONTEXT_INDEX)));
-  __ mov(result, ContextOperand(result, instr->slot_index()));
+  __ mov(result, ContextOperand(context, instr->slot_index()));
 }
 
 
 void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register value = ToRegister(instr->value());
-  __ mov(context,
-         Operand(context, Context::SlotOffset(Context::FCONTEXT_INDEX)));
   __ mov(ContextOperand(context, instr->slot_index()), value);
   if (instr->needs_write_barrier()) {
     Register temp = ToRegister(instr->TempAt(0));
     int offset = Context::SlotOffset(instr->slot_index());
     __ RecordWrite(context, offset, value, temp);
   }
 }
 
 
 void LCodeGen::DoLoadNamedField(LLoadNamedField* instr) {
@@ skipping 1698 matching lines @@
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32