message: Change default CPU target for ARM macOS and iOS.
diff: @@ -1186,7 +1186,18 @@ Target::Target(Arch arch, const char *cpu, ISPCTarget ispc_target, bool pic, boo
  if (arch == Arch::arm) {
  CPUID = CPU_CortexA9;
  } else if (arch == Arch::aarch64) {
  + if (g->target_os == TargetOS::ios) {
  + CPUID = CPU_AppleA7;
  + } else if (g->target_os == TargetOS::macos) {
  + // Open source LLVM doesn't has definition for M1 CPU, so use the latest iPhone CPU.
  +#if ISPC_LLVM_VERSION >= ISPC_LLVM_12_0
  + CPUID = CPU_AppleA14;
  +#else
  + CPUID = CPU_AppleA13;
  +#endif
  + } else {
  CPUID = CPU_CortexA35;
  + }
  } else {
  UNREACHABLE();
  }
  