target/arm: Define and use any_predinv isar_feature test

Instead of open-coding "ARM_FEATURE_AARCH64 ? aa64_predinv: aa32_predinv",
define and use an any_predinv isar_feature test function.
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Message-id: 20200214175116.9164-5-peter.maydell@linaro.org

target/arm/cpu.h

@@ -3677,6 +3677,11 @@ static inline bool isar_feature_any_fp16(const ARMISARegisters *id)
     return isar_feature_aa64_fp16(id) || isar_feature_aa32_fp16_arith(id);
 }
 
+static inline bool isar_feature_any_predinv(const ARMISARegisters *id)
+{
+    return isar_feature_aa64_predinv(id) || isar_feature_aa32_predinv(id);
+}
+
 /*
  * Forward to the above feature tests given an ARMCPU pointer.
  */

target/arm/helper.c

@@ -7721,14 +7721,7 @@ void register_cp_regs_for_features(ARMCPU *cpu)
 #endif /*CONFIG_USER_ONLY*/
 #endif
 
-    /*
-     * While all v8.0 cpus support aarch64, QEMU does have configurations
-     * that do not set ID_AA64ISAR1, e.g. user-only qemu-arm -cpu max,
-     * which will set ID_ISAR6.
-     */
-    if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)
-        ? cpu_isar_feature(aa64_predinv, cpu)
-        : cpu_isar_feature(aa32_predinv, cpu)) {
+    if (cpu_isar_feature(any_predinv, cpu)) {
         define_arm_cp_regs(cpu, predinv_reginfo);
     }