AArch64: improve usage of TargetReg() and friends.

TargetReg(arg1) does now always return a 32-bit register. We also avoid
using this function directly and rather use the two-arguments overload
or TargetPtrReg().

Change-Id: I746b3c29a2a2553b399b5c3e7ee3887c7e7c52c3
diff --git a/compiler/dex/quick/arm64/codegen_arm64.h b/compiler/dex/quick/arm64/codegen_arm64.h
index e4eeeaf..de97653 100644
--- a/compiler/dex/quick/arm64/codegen_arm64.h
+++ b/compiler/dex/quick/arm64/codegen_arm64.h
@@ -105,16 +105,14 @@
     // Required for target - register utilities.
     RegStorage TargetReg(SpecialTargetRegister reg) OVERRIDE;
     RegStorage TargetReg(SpecialTargetRegister symbolic_reg, WideKind wide_kind) OVERRIDE {
-      RegStorage reg = TargetReg(symbolic_reg);
       if (wide_kind == kWide || wide_kind == kRef) {
-        return (reg.Is64Bit()) ? reg : As64BitReg(reg);
+        return As64BitReg(TargetReg(symbolic_reg));
       } else {
-        return (reg.Is32Bit()) ? reg : As32BitReg(reg);
+        return Check32BitReg(TargetReg(symbolic_reg));
       }
     }
     RegStorage TargetPtrReg(SpecialTargetRegister symbolic_reg) OVERRIDE {
-      RegStorage reg = TargetReg(symbolic_reg);
-      return (reg.Is64Bit() ? reg : As64BitReg(reg));
+      return As64BitReg(TargetReg(symbolic_reg));
     }
     RegStorage GetArgMappingToPhysicalReg(int arg_num);
     RegLocation GetReturnAlt();