[arm64][turbofan] Do not use ubfx for shr+and combination for mask=0.

test/cctest/compiler/test-run-machops.cc

 // Copyright 2014 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 <cmath>
 #include <functional>
 #include <limits>
 
 #include "src/base/bits.h"
 #include "src/base/ieee754.h"
@@ skipping 6721 matching lines @@
 }
 
 TEST(Regression5951) {
   BufferedRawMachineAssemblerTester<int64_t> m(MachineType::Int64());
   m.Return(m.Word64And(m.Word64Shr(m.Parameter(0), m.Int64Constant(0)),
                        m.Int64Constant(0xffffffffffffffffl)));
   int64_t input = 1234;
   CHECK_EQ(input, m.Call(input));
 }
 
+TEST(Regression6046a) {
+  BufferedRawMachineAssemblerTester<int64_t> m;
+  m.Return(m.Word64Shr(m.Word64And(m.Int64Constant(0), m.Int64Constant(0)),
+                       m.Int64Constant(64)));
+  CHECK_EQ(0, m.Call());
+}
+
+TEST(Regression6046b) {
+  BufferedRawMachineAssemblerTester<int32_t> m;
+  m.Return(m.Word32Shr(m.Word32And(m.Int32Constant(0), m.Int32Constant(0)),
+                       m.Int32Constant(32)));
+  CHECK_EQ(0, m.Call());
+}
+
 #endif  // V8_TARGET_ARCH_64_BIT
 
 TEST(Regression6028) {
   BufferedRawMachineAssemblerTester<int32_t> m;
   m.Return(m.Word32Equal(
       m.Word32And(m.Int32Constant(0x23),
                   m.Word32Sar(m.Int32Constant(1), m.Int32Constant(18))),
       m.Int32Constant(0)));
   CHECK_EQ(1, m.Call());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8