In Semantic meanings^x, Conditionals^x

Simplest explanation on usage (I hope it's simple XD): Could or Couldn't: Talking about the possibility or lack of a possibility. "It couldn't rain today" = "There's no possibility of it raining." Can or Can't: Talking about the ability or lack of ability: "It can't rain today" = "It is not...

I see no grammatical form or semantic meaning in had have had, and googling (a mere 11,000 hits when I tried it) produces not one grammatically reputable webpage.I can envision I'd have had being misinterpreted as had have had by those who confuse had rather and would rather-- but those would...