[PATCH] D61132: [builtins] run-time support for sparse maps in llvm

[Hans Wennborg via Phabricator via llvm-commits]

hans added a comment.

I'm also not really familiar with code in compiler-rt.

However, as pointed out in https://bugs.llvm.org/show_bug.cgi?id=39013#c4 the compiler-rt builtins are not available for most targets.

I can mostly speak for Chromium, but in those builds we use libgcc on Linux, the Windows libraries on Windows, and on Mac we use the system's compiler-rt.

This means if you want to do any switch transformation that relies on this runtime function, that transformation will have to be disabled in general, and at that point I'm not sure it makes sense to have it in tree.

I'd suggest trying to emit the runtime code that your switch transformation relies on as LLVM IR instead. That might actually be easier, because e.g. you can rely on LLVM's popcount intrinsic, and you can do lower level stuff that is maybe useful.


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https://reviews.llvm.org/D61132