Given a generated module in memory, how do you run all available optimisations on it?
Tutorial section 4.3 at http://llvm.org/docs/tutorial/LangImpl4.html picks out just a few optimisations, which makes sense for a JIT compiler on short running code, but I’m looking at long-running code where it would be worthwhile to start off applying all of them and possibly selectively disable any that turn out not to be useful.
C:\llvm\tools\opt\opt.cpp seems to be a program that runs optimisations from IR to IR, and perhaps runs all of the applicable ones; main() seems to contain a list of optimisation pass initialisations (though only the ones applicable where we aren’t generating machine code yet). Would copy-pasting the code from that file be the right starting point?
On the other hand, if so, I would have expected that code to occur again in the clang source tree, because clang likewise has a -O3 option, but it doesn’t seem to. That suggests to me that I’m confused about how things are organized. What am I missing?