llc: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/llc - from package: llvm

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/llc - from package: llvm
/usr/lib/llvm-3.4/bin/llc - from package: llvm-3.4
/usr/lib/llvm-3.5/bin/llc - from package: llvm-3.5

You may install the required package with command apt-get install {package}

Error in other languages:
llc: bevel nie gevind nie
llc: comandă negăsită
llc: comando não encontrado
llc: commande introuvable
llc: command not found
llc: käsku ei ole
llc: không tìm thấy lệnh
llc: komanda nerasta
llc: Kommando nicht gefunden.
llc: kommandot finns inte
llc: komut yok
llc: nie znaleziono polecenia
llc: níor aimsíodh an t-ordú
llc: no se encontró la orden
llc: no s'ha trobat l'ordre
llc: opdracht niet gevonden
llc: parancs nem található
llc: perintah tidak ditemukan
llc: príkaz nenájdený
llc: příkaz nenalezen
llc: команда не найдена
llc: командата не е открита
llc: 命令找不到
llc: コマンドが見つかりません