The appropriate tense depends on the situation in which you’re saying it.
In real life, if – late in a particular day – you were commenting on someone’s behaviour throughout that day, you’d say “He’s been irritable all day” (implying that he still is).
Only if you were commenting on someone’s habitual behaviour, in certain circumstances, would you say “If she doesn’t call him in the morning, he’s irritable all day”.
The other situation in which you’d use the simple present (in this use called the narrative or historic present) is if you were describing what happens in a particular book or play or film. For example: “After hearing the bad news, he (one of the characters) is irritable all day”.