[Atomics] Handle conversion to SMI in builtin, not code stub.

src/arm64/code-stubs-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 5989 matching lines @@
   __ B(u32);     // Uint32Array
   __ B(&abort);  // Float32Array
   __ B(&abort);  // Float64Array
   __ B(u8c);     // Uint8ClampedArray
   __ EndBlockPools();
 
   __ Bind(&abort);
   __ Abort(kNoReason);
 }
 
-void ReturnUnsignedInteger32(MacroAssembler* masm, FPRegister dst,
-                             Register value, Register scratch,
-                             Register scratch2) {
-  Label not_smi, call_runtime;
-  __ Tbnz(value, 31, &not_smi);
-  __ SmiTag(x0, value);
-  __ Ret();
-
-  __ Bind(&not_smi);
-  __ Ucvtf(dst, value);
-  __ AllocateHeapNumber(x0, &call_runtime, scratch, scratch2, dst);
-  __ Ret();
-
-  __ Bind(&call_runtime);
-  {
-    FrameScope scope(masm, StackFrame::INTERNAL);
-    __ CallRuntimeSaveDoubles(Runtime::kAllocateHeapNumber);
-    __ Str(value, FieldMemOperand(x0, HeapNumber::kValueOffset));
-  }
-  __ Ret();
-}
-
 }  // anonymous namespace
 
 void AtomicsLoadStub::Generate(MacroAssembler* masm) {
   Register object = x1;
   Register index = x0;  // Index is an untagged word32.
   Register backing_store = x2;
   Label i8, u8, i16, u16, i32, u32;
 
   GetTypedArrayBackingStore(masm, backing_store, object, x3, d0);
   TypedArrayJumpTable(masm, object, x3, x4, &i8, &u8, &i16, &u16, &i32, &u32,
                       &u8);
 
   __ Bind(&i8);
   __ Ldrsb(x0, MemOperand(backing_store, index));
   __ Dmb(InnerShareable, BarrierAll);
-  __ SmiTag(x0);
   __ Ret();
 
   __ Bind(&u8);
   __ Ldrb(x0, MemOperand(backing_store, index));
   __ Dmb(InnerShareable, BarrierAll);
-  __ SmiTag(x0);
   __ Ret();
 
   __ Bind(&i16);
   __ Ldrsh(x0, MemOperand(backing_store, index, UXTW, 1));
   __ Dmb(InnerShareable, BarrierAll);
-  __ SmiTag(x0);
   __ Ret();
 
   __ Bind(&u16);
   __ Ldrh(x0, MemOperand(backing_store, index, UXTW, 1));
   __ Dmb(InnerShareable, BarrierAll);
-  __ SmiTag(x0);
   __ Ret();
 
   __ Bind(&i32);
   __ Ldrsw(x0, MemOperand(backing_store, index, UXTW, 2));
   __ Dmb(InnerShareable, BarrierAll);
-  DCHECK(SmiValuesAre32Bits());
-  __ SmiTag(x0);
   __ Ret();
 
   __ Bind(&u32);
   __ Ldr(w0, MemOperand(backing_store, index, UXTW, 2));
   __ Dmb(InnerShareable, BarrierAll);
-  ReturnUnsignedInteger32(masm, d0, x0, x1, x2);
+  __ Ret();
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64