50 Cent's leaning into comparisons between himself and Donald Trump after the former prez survived a shooting, but he won't be attending or performing in support of Trump at the Republican National Convention ... TMZ has learned.

50 Cent's rep tells us ... "He is not attending [the RNC], as he is slated to be in Shreveport preparing for his "Humor and Harmony" festival." Reports surfaced on Monday declaring 50 would be on stage in Milwaukee to play a gig during the convention, but that was news to his camp ... and they quickly denied it.

What made the report believable is the fact 50 invoked Trump during his Saturday night concert in Boston. As we reported, the rapper projected a popular meme -- his "Get Rich or Die Tryin" album cover with Trump's face replacing his -- in the screen behind him as he performed "Many Men."

If ya didn't know, the song is about 50's enemies gunning for him.

Mind you, this was just a few hours after the assassination attempt in Pennsylvania -- so, 50 Cent was aware by then that folks on social media were drawing the parallel between Trump and him ... as 50 famously survived getting shot 9 times back in 2000.

All that being said, 50 Cent's people say he is NOT booked for an encore at the RNC.