[E] Couldn't get control-flow flattening information

[WYK15]

pyhexraysdeob didn't work.
I pressed F5 and nothing changed,it's still obfuscated.
check the IDA log，and it says " Couldn't get control-flow flattening information".
the file is .elf(arm64) and ollvmed. here is IDA log:
Hex-rays version 7.5.0.201028 has been detected, Python Microcode explorer (pyhexraysdeob) ready to use Python Microcode explorer (pyhexraysdeob) is now activated [E] Couldn't get control-flow flattening information F17C: conditional instruction was optimized away because of 'w26.4==77E4CF90' F1B8: conditional instruction was optimized away because of 'w26.4==F7667548' F11C: conditional instruction was optimized away because of 'w28.4==3B64D8B4' F1DC: conditional instruction was optimized away because of 'w28.4==5AEE32E5' F0C4: variable 'v4' is possibly undefined F0C8: variable 'v5' is possibly undefined F0E0: variable 'v8' is possibly undefined F0E4: variable 'v7' is possibly undefined F0E8: variable 'v6' is possibly undefined F1F0: variable 'v19' is possibly undefined F200: variable 'v20' is possibly undefined F23C: variable 'v22' is possibly undefined F248: variable 'v21' is possibly undefined F254: variable 'v18' is possibly undefined F264: variable 'v16' is possibly undefined F264: variable 'v17' is possibly undefined F274: variable 'v23' is possibly undefined