[builtins] Simplify String constructor code.

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 39db8ebe1c723880508ef2f29afdb97e0f97cf75..0361828eb5f901823404ca4ad571cfcc189b5f30 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -2247,90 +2247,6 @@ void MacroAssembler::Test(const Operand& src, Smi* source) {
 // ----------------------------------------------------------------------------
 
 
-void MacroAssembler::LookupNumberStringCache(Register object,
-                                             Register result,
-                                             Register scratch1,
-                                             Register scratch2,
-                                             Label* not_found) {
-  // Use of registers. Register result is used as a temporary.
-  Register number_string_cache = result;
-  Register mask = scratch1;
-  Register scratch = scratch2;
-
-  // Load the number string cache.
-  LoadRoot(number_string_cache, Heap::kNumberStringCacheRootIndex);
-
-  // Make the hash mask from the length of the number string cache. It
-  // contains two elements (number and string) for each cache entry.
-  SmiToInteger32(
-      mask, FieldOperand(number_string_cache, FixedArray::kLengthOffset));
-  shrl(mask, Immediate(1));
-  subp(mask, Immediate(1));  // Make mask.
-
-  // Calculate the entry in the number string cache. The hash value in the
-  // number string cache for smis is just the smi value, and the hash for
-  // doubles is the xor of the upper and lower words. See
-  // Heap::GetNumberStringCache.
-  Label is_smi;
-  Label load_result_from_cache;
-  JumpIfSmi(object, &is_smi);
-  CheckMap(object,
-           isolate()->factory()->heap_number_map(),
-           not_found,
-           DONT_DO_SMI_CHECK);
-
-  STATIC_ASSERT(8 == kDoubleSize);
-  movl(scratch, FieldOperand(object, HeapNumber::kValueOffset + 4));
-  xorp(scratch, FieldOperand(object, HeapNumber::kValueOffset));
-  andp(scratch, mask);
-  // Each entry in string cache consists of two pointer sized fields,
-  // but times_twice_pointer_size (multiplication by 16) scale factor
-  // is not supported by addrmode on x64 platform.
-  // So we have to premultiply entry index before lookup.
-  shlp(scratch, Immediate(kPointerSizeLog2 + 1));
-
-  Register index = scratch;
-  Register probe = mask;
-  movp(probe,
-       FieldOperand(number_string_cache,
-                    index,
-                    times_1,
-                    FixedArray::kHeaderSize));
-  JumpIfSmi(probe, not_found);
-  movsd(xmm0, FieldOperand(object, HeapNumber::kValueOffset));
-  ucomisd(xmm0, FieldOperand(probe, HeapNumber::kValueOffset));
-  j(parity_even, not_found);  // Bail out if NaN is involved.
-  j(not_equal, not_found);  // The cache did not contain this value.
-  jmp(&load_result_from_cache);
-
-  bind(&is_smi);
-  SmiToInteger32(scratch, object);
-  andp(scratch, mask);
-  // Each entry in string cache consists of two pointer sized fields,
-  // but times_twice_pointer_size (multiplication by 16) scale factor
-  // is not supported by addrmode on x64 platform.
-  // So we have to premultiply entry index before lookup.
-  shlp(scratch, Immediate(kPointerSizeLog2 + 1));
-
-  // Check if the entry is the smi we are looking for.
-  cmpp(object,
-       FieldOperand(number_string_cache,
-                    index,
-                    times_1,
-                    FixedArray::kHeaderSize));
-  j(not_equal, not_found);
-
-  // Get the result from the cache.
-  bind(&load_result_from_cache);
-  movp(result,
-       FieldOperand(number_string_cache,
-                    index,
-                    times_1,
-                    FixedArray::kHeaderSize + kPointerSize));
-  IncrementCounter(isolate()->counters()->number_to_string_native(), 1);
-}
-
-
 void MacroAssembler::JumpIfNotString(Register object,
                                      Register object_map,
                                      Label* not_string,