ARM64: Use the shifter operands.

This introduces architecture-specific instruction simplification.
On ARM64 we try to merge shifts and sign-extension operations into
arithmetic and logical instructions.

For example for the Java code

    int res = a + (b << 5);

we would generate

    lsl w3, w2, #5
    add w0, w1, w3

and we now generate

    add w0, w1, w2, lsl #5

Change-Id: Ic03bdff44a1c12e21ddff1b0513bd32a730742b7
diff --git a/compiler/optimizing/nodes_arm64.cc b/compiler/optimizing/nodes_arm64.cc
new file mode 100644
index 0000000..ac2f093
--- /dev/null
+++ b/compiler/optimizing/nodes_arm64.cc
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "common_arm64.h"
+#include "nodes.h"
+
+namespace art {
+
+using arm64::helpers::CanFitInShifterOperand;
+
+void HArm64DataProcWithShifterOp::GetOpInfoFromInstruction(HInstruction* instruction,
+                                                           /*out*/OpKind* op_kind,
+                                                           /*out*/int* shift_amount) {
+  DCHECK(CanFitInShifterOperand(instruction));
+  if (instruction->IsShl()) {
+    *op_kind = kLSL;
+    *shift_amount = instruction->AsShl()->GetRight()->AsIntConstant()->GetValue();
+  } else if (instruction->IsShr()) {
+    *op_kind = kASR;
+    *shift_amount = instruction->AsShr()->GetRight()->AsIntConstant()->GetValue();
+  } else if (instruction->IsUShr()) {
+    *op_kind = kLSR;
+    *shift_amount = instruction->AsUShr()->GetRight()->AsIntConstant()->GetValue();
+  } else {
+    DCHECK(instruction->IsTypeConversion());
+    Primitive::Type result_type = instruction->AsTypeConversion()->GetResultType();
+    Primitive::Type input_type = instruction->AsTypeConversion()->GetInputType();
+    int result_size = Primitive::ComponentSize(result_type);
+    int input_size = Primitive::ComponentSize(input_type);
+    int min_size = std::min(result_size, input_size);
+    // This follows the logic in
+    // `InstructionCodeGeneratorARM64::VisitTypeConversion()`.
+    if (result_type == Primitive::kPrimInt && input_type == Primitive::kPrimLong) {
+      // There is actually nothing to do. The register will be used as a W
+      // register, discarding the top bits. This is represented by the default
+      // encoding 'LSL 0'.
+      *op_kind = kLSL;
+      *shift_amount = 0;
+    } else if (result_type == Primitive::kPrimChar ||
+               (input_type == Primitive::kPrimChar && input_size < result_size)) {
+      *op_kind = kUXTH;
+    } else {
+      switch (min_size) {
+        case 1: *op_kind = kSXTB; break;
+        case 2: *op_kind = kSXTH; break;
+        case 4: *op_kind = kSXTW; break;
+        default:
+          LOG(FATAL) << "Unexpected min size " << min_size;
+      }
+    }
+  }
+}
+
+std::ostream& operator<<(std::ostream& os, const HArm64DataProcWithShifterOp::OpKind op) {
+  switch (op) {
+    case HArm64DataProcWithShifterOp::kLSL:  return os << "LSL";
+    case HArm64DataProcWithShifterOp::kLSR:  return os << "LSR";
+    case HArm64DataProcWithShifterOp::kASR:  return os << "ASR";
+    case HArm64DataProcWithShifterOp::kUXTB: return os << "UXTB";
+    case HArm64DataProcWithShifterOp::kUXTH: return os << "UXTH";
+    case HArm64DataProcWithShifterOp::kUXTW: return os << "UXTW";
+    case HArm64DataProcWithShifterOp::kSXTB: return os << "SXTB";
+    case HArm64DataProcWithShifterOp::kSXTH: return os << "SXTH";
+    case HArm64DataProcWithShifterOp::kSXTW: return os << "SXTW";
+    default:
+      LOG(FATAL) << "Invalid OpKind " << static_cast<int>(op);
+      UNREACHABLE();
+  }
+}
+
+}  // namespace art