Tentative implementation of string slices (hidden under the flag --string-slices).

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 9951d2540bb1cab9136db7c2acf028cc04584473..d305be2bf6ff3a6b2238fb2914fc8c7b655a42b9 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -2060,7 +2060,9 @@ LInstruction* LChunkBuilder::DoStringCharCodeAt(HStringCharCodeAt* instr) {
   LOperand* string = UseRegister(instr->string());
   LOperand* index = UseRegisterOrConstant(instr->index());
   LOperand* context = UseAny(instr->context());
-  LStringCharCodeAt* result = new LStringCharCodeAt(context, string, index);
+  LOperand* temp = TempRegister();
+  LStringCharCodeAt* result = new LStringCharCodeAt(context, string,
+                                                    index, temp);
   return AssignEnvironment(AssignPointerMap(DefineAsRegister(result)));
 }