Complex sentence: This form of garbage collection has been studied in the Mercury programming language, and it saw greater usage with the introduction of LLVM's automatic reference counter (ARC) into Apple's ecosystem (iOS and OS X) in 2011.
Split into simpler sentences: This form of garbage collection has been studied in the Mercury programming language. Greater usage saw such an automatic compile-time memory management with the introduction of LLVM's automatic reference counter (ARC) into Apple's ecosystem (iOS and MacOS) in 2011.