Add support for int-to-byte in the optimizing compiler.

- Add support for the int-to-byte Dex instruction in the
  optimizing compiler.
- Implement the ARM and Thumb-2 SBFX instructions.
- Generate x86, x86-64 and ARM (but not ARM64) code for
  char to byte, short to byte and int to byte
  HTypeConversion nodes.
- Add related tests to test/422-type-conversion.

Change-Id: Ic8b8911b90d4b5281fad15bcee96bc3ee85dc577
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index be326dc..0403c5e 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -1348,6 +1348,22 @@
   Primitive::Type result_type = conversion->GetResultType();
   Primitive::Type input_type = conversion->GetInputType();
   switch (result_type) {
+    case Primitive::kPrimByte:
+      switch (input_type) {
+        case Primitive::kPrimShort:
+        case Primitive::kPrimInt:
+        case Primitive::kPrimChar:
+          // int-to-byte conversion.
+          locations->SetInAt(0, Location::RequiresRegister());
+          locations->SetOut(Location::RequiresRegister(), Location::kNoOutputOverlap);
+          break;
+
+        default:
+          LOG(FATAL) << "Unexpected type conversion from " << input_type
+                     << " to " << result_type;
+      }
+      break;
+
     case Primitive::kPrimInt:
       switch (input_type) {
         case Primitive::kPrimLong:
@@ -1410,6 +1426,21 @@
   Primitive::Type result_type = conversion->GetResultType();
   Primitive::Type input_type = conversion->GetInputType();
   switch (result_type) {
+    case Primitive::kPrimByte:
+      switch (input_type) {
+        case Primitive::kPrimShort:
+        case Primitive::kPrimInt:
+        case Primitive::kPrimChar:
+          // int-to-byte conversion.
+          __ sbfx(out.As<Register>(), in.As<Register>(), 0, 8);
+          break;
+
+        default:
+          LOG(FATAL) << "Unexpected type conversion from " << input_type
+                     << " to " << result_type;
+      }
+      break;
+
     case Primitive::kPrimInt:
       switch (input_type) {
         case Primitive::kPrimLong: