Comment by saagarjha

> LLVM: Pretty much everyone who has created a programming language with it has complained about its design. gingerbill, Jon Blow, and Andrew Kelley have all complained about it. LLVM is a good idea, but it that idea was executed better by Ken Thompson with his C compiler for Plan 9, and then again with his Go compiler design. Ken decided to create his own "architecture agnostic" assembly, which is very similar to the IR idea with LLVM.

I suggest you ask around to see what the consensus is for which compiler is actually mature. Hint: for all its warts, nobody is writing a seriously optimized language in any of the options you listed besides LLVM.