[turbofan] Recognize sign extension of 8-bit and 16-bit values on arm64.

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 2111 matching lines @@
   EXPECT_EQ(s.ToVreg(p1), s.ToVreg(s[0]->InputAt(1)));
   ASSERT_EQ(1U, s[0]->OutputCount());
   EXPECT_EQ(kArm64Asr, s[1]->arch_opcode());
   ASSERT_EQ(2U, s[1]->InputCount());
   EXPECT_EQ(s.ToVreg(s[0]->Output()), s.ToVreg(s[1]->InputAt(0)));
   EXPECT_EQ(32, s.ToInt64(s[1]->InputAt(1)));
   ASSERT_EQ(1U, s[1]->OutputCount());
   EXPECT_EQ(s.ToVreg(n), s.ToVreg(s[1]->Output()));
 }
 
+
+TEST_F(InstructionSelectorTest, Word32SarWithWord32Shl) {
+  {
+    StreamBuilder m(this, kMachInt32, kMachInt32);
+    Node* const p0 = m.Parameter(0);
+    Node* const r =
+        m.Word32Sar(m.Word32Shl(p0, m.Int32Constant(24)), m.Int32Constant(24));
+    m.Return(r);
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Sxtb32, s[0]->arch_opcode());
+    ASSERT_EQ(1U, s[0]->InputCount());
+    EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[0]->InputAt(0)));
+    ASSERT_EQ(1U, s[0]->OutputCount());
+    EXPECT_EQ(s.ToVreg(r), s.ToVreg(s[0]->Output()));
+  }
+  {
+    StreamBuilder m(this, kMachInt32, kMachInt32);
+    Node* const p0 = m.Parameter(0);
+    Node* const r =
+        m.Word32Sar(m.Word32Shl(p0, m.Int32Constant(16)), m.Int32Constant(16));
+    m.Return(r);
+    Stream s = m.Build();
+    ASSERT_EQ(1U, s.size());
+    EXPECT_EQ(kArm64Sxth32, s[0]->arch_opcode());
+    ASSERT_EQ(1U, s[0]->InputCount());
+    EXPECT_EQ(s.ToVreg(p0), s.ToVreg(s[0]->InputAt(0)));
+    ASSERT_EQ(1U, s[0]->OutputCount());
+    EXPECT_EQ(s.ToVreg(r), s.ToVreg(s[0]->Output()));
+  }
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8