The best replacement for llvm is gcc.

The best alternatives to llvm are rated as following:
★★★★★  gcc
★★★  clang
★★★  jvm
★★  c--
★  parrot
  msvc

Your alternative for llvm is not listed? Suggest!
Speaking about llvm, one probably shouldn't forget about clang.

Other search terms related to llvm and their ratings are:
★★★★★ clang
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llvm
gcc
clang