(Replying to PARENT post)

How does LLVM cope with the array semantics? I was under the impression that the noalias attribute in the IR was not activated in such a way as to enable the optimizations that make Fortran so fast.

👤throwaway17_17🕑2y🔼0🗨️0

(Replying to PARENT post)

My experience with LLVM so far has been that is possible to get maximum speed as long as we generate the correct and clean LLVM IR, and do many of the high level optimizations ourselves.

If LLVM has any downsides, it is that it is hard to run in the browser, so we don't use it for https://dev.lfortran.org/, and that it is slow to compile (both LLVM itself, as well as it makes LFortran slow to compile, compared to our direct WASM/x64 backends). But when it comes to runtime performance of the generated code, LLVM seems very good.

👤certik🕑2y🔼0🗨️0

(Replying to PARENT post)

Rust drove the fixes needed in llvm to support noalias. They went through a couple reverts before seemingly fixing everything. If lfortran emits noalias, llvm can probably handle it now.

👤galangalalgol🕑2y🔼0🗨️0