hoy added a comment. In D83906#4182904 <https://reviews.llvm.org/D83906#4182904>, @dexonsmith wrote:
> In D83906#4182847 <https://reviews.llvm.org/D83906#4182847>, @hoy wrote: > >> As far as I know, the optimizer IPO pass that infers function attributes >> (i..e `InferFunctionAttrsPass`) is placed at the very beginning of the >> optimization pipeline. Does this sound to you that the side effects >> computed for linkonce_odr functions there can be trusted by the rest of the >> pipeline? > > Depends what you mean by "trusted". It assumes the attributes accurately > describe the function it sees. The properties promised there will apply > if/when the code is inlined. But, since the commit in 2016, it doesn't trust > that they fully describe the source semantics, so IPA ignores them when the > function is not inlined. > > Note that the optimizer doesn't know if its input IR has already been > optimized. Is this the first optimizer that has run on the IR, or could side > effects have been refined away already? E.g., if the optimization pipeline in > question runs at LTO time, the compile-time optimization pipeline has already > run. Wondering if we can come up with a way to tell the optimizer about that, e.g., through a new module flag. When it comes to LTO, the selection of linkonce_odr symbols should already been done and the optimizer may be able to recompute the attributes based on pre-LTO attributes, or at least we can allow IPO to one module only, which should still do a better job than FE does? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D83906/new/ https://reviews.llvm.org/D83906 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
