steakhal added a comment. In D92634#2478503 <https://reviews.llvm.org/D92634#2478503>, @OikawaKirie wrote:
> Besides, as far as I am thinking, the compiler optimizes the expression as it > is literally inferable, i.e. the result should be determinable literally > during compilation. Otherwise, it will be computed during runtime. Therefore > I suggest you can do a similar check with the ASTMatcher, since the `and` and > `or` conjunctions will be removed in the CFG. I disagree on this. You can never be sure if a given function gets inlined or not, thus the context does matter for compiler optimizations. The given value might get constant folded and get the comparison/branch optimized away. In a path sensitive way, we will always suffer from the limitations of the constraint solver. > BTW, I cannot optimize function f to returning zero directly with GCC-10.2.1 > and Clang-10.0.1 under -O3. Should I add any other flags? Or it is version > specific? I don't think we should depend on implementation details. The only flag I would consider though if the `-fwarpv` as that defines the concrete semantics. --- I also agree with @NoQ's D92634#2478703 <https://reviews.llvm.org/D92634#2478703> comment. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D92634/new/ https://reviews.llvm.org/D92634 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
