The name McIntyre comes from Irish Gaelic mac an tsaoir "son of the carpenter". saor is "carpenter", which according to McBain's is from Proto-Celtic *sapiro-s "skill" from Proto-Indo-European *sep- "taste, perceive".
*sep- gives us savant and sapient from French from Latin sapio "to taste, be wise".
In Proto-Germanic it became something like *sap- (assuming an alternate PIE form *sab-), then English sap and Middle High German saft "juice, sap". This became Yiddish זאַפֿטיק zaftik "juicy", borrowed into English as zaftig.
The connection of *sep- with Gaelic saor is probably controversial; it's not given in Pokorny. But it's too cool not to mention.