Difference between "huge", "enormous" and "gigantic"

Among the words huge, enormous and gigantic, does one word refer to something bigger than another does, or do they all refer to the same size?

It’s not so much that they describe varying degrees of size as that they are used in different contexts. For example, we might speak of enormous pressure, but not of gigantic pressure, or of enormous power, but not of huge power. Moreover, I suspect gigantic is more often used attributively than predicatively (a gigantic loss rather than the loss was gigantic). Semantically related words like these sometimes appear in predominantly positive or negative contexts, but it would take considerable research to establish that that was the case with these three.

They are all synonyms, so no none is bigger than any other.