Inline array loads in loops directly in the code instead of always...

src/builtins-ia32.cc

 // Copyright 2006-2008 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 597 matching lines @@
   __ mov(eax, Operand(ebp, kIndexOffset));
   __ jmp(&entry);
   __ bind(&loop);
   __ mov(ecx, Operand(ebp, 2 * kPointerSize));  // load arguments
   __ push(ecx);
   __ push(eax);
 
   // Use inline caching to speed up access to arguments.
   Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
   __ call(ic, RelocInfo::CODE_TARGET);
+  // Make sure that we do not have a test instruction after the
+  // call.  A test instruction after the call is used to
+  // indicate that we have generated an inline version of the
+  // keyed load.
+  __ nop();

[Kasper Lund, 2008/12/22 09:52:13]

Is this really necessary? The next instruction here is always an 'add'
instruction. Maybe just document that it has to be that way.

[Mads Ager (chromium), 2008/12/22 12:59:11]

This is definitely not necessary.  I alternated between having it there and not
a couple of times.  I'll remove the nop and update the comment to state that it
is important that the next instruction is not a test instruction.

 
   // Remove IC arguments from the stack and push the nth argument.
   __ add(Operand(esp), Immediate(2 * kPointerSize));
   __ push(eax);
 
   // Update the index on the stack and in register eax.
   __ mov(eax, Operand(ebp, kIndexOffset));
   __ add(Operand(eax), Immediate(1 << kSmiTagSize));
   __ mov(Operand(ebp, kIndexOffset), eax);
 
@@ skipping 122 matching lines @@
   // Dont adapt arguments.
   // -------------------------------------------
   __ bind(&dont_adapt_arguments);
   __ jmp(Operand(edx));
 }
 
 
 #undef __
 
 } }  // namespace v8::internal