People at Apple working on JavaScriptCore (Safari's JS engine) have recently added a fourth-tier JIT using LLVM, so very much run for only very-very-very-hot code (of course, by waiting for it to become very-very-very-hot, you've already lost a time you could've gained). I can see LLVM making its way into more JITing compilers in such ways: as an ultimate solution where it is clear it's worthwhile spending a lot of time compiling code.
The node.js server case seems worthwhile to bring up here: node.js servers are typically run for days or weeks on end. An extra few milliseconds (or even a second or two) isn't significant if it makes a noticeable difference in performance.
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People at Apple working on JavaScriptCore (Safari's JS engine) have recently added a fourth-tier JIT using LLVM, so very much run for only very-very-very-hot code (of course, by waiting for it to become very-very-very-hot, you've already lost a time you could've gained). I can see LLVM making its way into more JITing compilers in such ways: as an ultimate solution where it is clear it's worthwhile spending a lot of time compiling code.
The node.js server case seems worthwhile to bring up here: node.js servers are typically run for days or weeks on end. An extra few milliseconds (or even a second or two) isn't significant if it makes a noticeable difference in performance.