Using array index hash code for string-to-number conversion.

src/x64/ic-x64.cc

Index: src/x64/ic-x64.cc
===================================================================
--- src/x64/ic-x64.cc	(revision 5357)
+++ src/x64/ic-x64.cc	(working copy)
@@ -572,32 +572,7 @@
 }
 
 
-// Picks out an array index from the hash field.
-static void GenerateIndexFromHash(MacroAssembler* masm,
-                                  Register key,
-                                  Register hash) {
-  // Register use:
-  //   key - holds the overwritten key on exit.
-  //   hash - holds the key's hash. Clobbered.
 
-  // The assert checks that the constants for the maximum number of digits
-  // for an array index cached in the hash field and the number of bits
-  // reserved for it does not conflict.
-  ASSERT(TenToThe(String::kMaxCachedArrayIndexLength) <
-         (1 << String::kArrayIndexValueBits));
-  // We want the smi-tagged index in key. Even if we subsequently go to
-  // the slow case, converting the key to a smi is always valid.
-  // key: string key
-  // hash: key's hash field, including its array index value.
-  __ and_(hash, Immediate(String::kArrayIndexValueMask));
-  __ shr(hash, Immediate(String::kHashShift));
-  // Here we actually clobber the key which will be used if calling into
-  // runtime later. However as the new key is the numeric value of a string key
-  // there is no difference in using either key.
-  __ Integer32ToSmi(key, hash);
-}
-
-
 void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax    : key
@@ -743,7 +718,7 @@
   __ ret(0);
 
   __ bind(&index_string);
-  GenerateIndexFromHash(masm, rax, rbx);
+  __ IndexFromHash(rbx, rax);
   __ jmp(&index_smi);
 }
 
@@ -1599,7 +1574,7 @@
   GenerateMiss(masm, argc);
 
   __ bind(&index_string);
-  GenerateIndexFromHash(masm, rcx, rbx);
+  __ IndexFromHash(rbx, rcx);
   // Now jump to the place where smi keys are handled.
   __ jmp(&index_smi);
 }