[turbofan] ARM64: Use zr to store immediate zero

test/unittests/compiler/arm64/instruction-selector-arm64-unittest.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 "test/unittests/compiler/instruction-selector-unittest.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
@@ skipping 2232 matching lines @@
     ASSERT_EQ(1U, s.size());
     EXPECT_EQ(memacc.str_opcode, s[0]->arch_opcode());
     EXPECT_EQ(kMode_MRI, s[0]->addressing_mode());
     ASSERT_EQ(3U, s[0]->InputCount());
     ASSERT_EQ(InstructionOperand::IMMEDIATE, s[0]->InputAt(1)->kind());
     EXPECT_EQ(index, s.ToInt32(s[0]->InputAt(1)));
     EXPECT_EQ(0U, s[0]->OutputCount());
   }
 }
 
+TEST_P(InstructionSelectorMemoryAccessTest, StoreZero) {
+  const MemoryAccess memacc = GetParam();
+  TRACED_FOREACH(int32_t, index, memacc.immediates) {
+    StreamBuilder m(this, MachineType::Int32(), MachineType::Pointer());
+    m.Store(memacc.type.representation(), m.Parameter(0),
+            m.Int32Constant(index), m.Int32Constant(0), kNoWriteBarrier);
+    m.Return(m.Int32Constant(0));
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(memacc.str_opcode, s[0]->arch_opcode());
+    EXPECT_EQ(kMode_MRI, s[0]->addressing_mode());
+    ASSERT_EQ(3U, s[0]->InputCount());
+    ASSERT_EQ(InstructionOperand::IMMEDIATE, s[0]->InputAt(1)->kind());
+    EXPECT_EQ(index, s.ToInt32(s[0]->InputAt(1)));
+    ASSERT_EQ(InstructionOperand::IMMEDIATE, s[0]->InputAt(2)->kind());
+    EXPECT_EQ(0, s.ToInt64(s[0]->InputAt(2)));
+    EXPECT_EQ(0U, s[0]->OutputCount());
+  }
+}
 
 INSTANTIATE_TEST_CASE_P(InstructionSelectorTest,
                         InstructionSelectorMemoryAccessTest,
                         ::testing::ValuesIn(kMemoryAccesses));
 
 
 // -----------------------------------------------------------------------------
 // Comparison instructions.
 
 static const MachInst2 kComparisonInstructions[] = {
@@ skipping 1077 matching lines @@
   ASSERT_EQ(2U, s[0]->InputCount());
   EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[0]->InputAt(0)));
   EXPECT_EQ(s.ToVreg(p1), s.ToVreg(s[0]->InputAt(1)));
   ASSERT_EQ(1U, s[0]->OutputCount());
   EXPECT_EQ(s.ToVreg(n), s.ToVreg(s[0]->Output()));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8