ARM64: Fix SHR logic error.

src/arm64/full-codegen-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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 2001 matching lines @@
   switch (op) {
     case Token::SAR:
       __ Ubfx(right, right, kSmiShift, 5);
       __ Asr(result, left, right);
       __ Bic(result, result, kSmiShiftMask);
       break;
     case Token::SHL:
       __ Ubfx(right, right, kSmiShift, 5);
       __ Lsl(result, left, right);
       break;
-    case Token::SHR: {
-      Label right_not_zero;
-      __ Cbnz(right, &right_not_zero);
-      __ Tbnz(left, kXSignBit, &stub_call);
-      __ Bind(&right_not_zero);
+    case Token::SHR:
+      // If `left >>> right` >= 0x80000000, the result is not representable in a
+      // signed 32-bit smi.
       __ Ubfx(right, right, kSmiShift, 5);
-      __ Lsr(result, left, right);
-      __ Bic(result, result, kSmiShiftMask);
+      __ Lsr(x10, left, right);
+      __ Tbnz(x10, kXSignBit, &stub_call);
+      __ Bic(result, x10, kSmiShiftMask);
       break;
-    }
     case Token::ADD:
       __ Adds(x10, left, right);
       __ B(vs, &stub_call);
       __ Mov(result, x10);
       break;
     case Token::SUB:
       __ Subs(x10, left, right);
       __ B(vs, &stub_call);
       __ Mov(result, x10);
       break;
@@ skipping 2870 matching lines @@
   return previous_;
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64