A64: Port LSeqStringSetChar optimizations from r16707 and r17521.

src/a64/macro-assembler-a64.cc

 // Copyright 2013 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 3601 matching lines @@
   ASSERT(TenToThe(String::kMaxCachedArrayIndexLength) <
          (1 << String::kArrayIndexValueBits));
   // We want the smi-tagged index in key.  kArrayIndexValueMask has zeros in
   // the low kHashShift bits.
   STATIC_ASSERT(kSmiTag == 0);
   Ubfx(hash, hash, String::kHashShift, String::kArrayIndexValueBits);
   SmiTag(index, hash);
 }
 
 
-void MacroAssembler::EmitSeqStringSetCharCheck(Register string,
-                                               Register index,
-                                               uint32_t encoding_mask) {
-  Register scratch = __ Tmp1();
+void MacroAssembler::EmitSeqStringSetCharCheck(
+    Register string,
+    Register index,
+    SeqStringSetCharCheckIndexType index_type,
+    Register scratch,
+    uint32_t encoding_mask) {
   ASSERT(!AreAliased(string, index, scratch));
 
-  AssertSmi(index);
+  if (index_type == kIndexIsSmi) {
+    AssertSmi(index);
+  }
 
   // Check that string is an object.
   ThrowIfSmi(string, kNonObject);
 
   // Check that string has an appropriate map.
   Ldr(scratch, FieldMemOperand(string, HeapObject::kMapOffset));
   Ldrb(scratch, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
+
   And(scratch, scratch, kStringRepresentationMask | kStringEncodingMask);
   Cmp(scratch, encoding_mask);
   ThrowIf(ne, kUnexpectedStringType);
 
-  // Check that the index points inside the string.
   Ldr(scratch, FieldMemOperand(string, String::kLengthOffset));
-  Cmp(index, scratch);
+  Cmp(index, index_type == kIndexIsSmi ? scratch : Operand::UntagSmi(scratch));
   ThrowIf(ge, kIndexIsTooLarge);
 
-  Cmp(index, Operand(Smi::FromInt(0)));
+  ASSERT_EQ(0, Smi::FromInt(0));
+  Cmp(index, 0);
   ThrowIf(lt, kIndexIsNegative);
 }
 
 
 void MacroAssembler::CheckAccessGlobalProxy(Register holder_reg,
                                             Register scratch,
                                             Label* miss) {
   // TODO(jbramley): Sort out the uses of Tmp0() and Tmp1() in this function.
   // The ARM version takes two scratch registers, and that should be enough for
   // all of the checks.
@@ skipping 1180 matching lines @@
   }
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_A64