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..., for example using empty inline assembly directives[1], are just ugly hacks. So I am wondering: Is there any support for preventing these kinds of optimizations? Or is there otherwise a "mostly recommended" way to prevent these optimizations? Thanks for your advice. All the best, Daan Sprenkels PS. Perhaps, would there be interest to add such a feature to LLVM? I found this repository on GitHub[2], adding a `__builtin_ct_choose` intrinsic to clang. But as far as I know, this has never been upstreamed. [1]: Chandler Carruth described this trick at CppCon15: <https://youtu.be/nXaxk27...

...an currently get this effect using __builtin_unpredictable in Clang. __builtin_unpredictable wasn't added for this purpose, and it's a hint not a forced behavior, but I believe that it causes the backend to prefer cmov to branches during lowering. -Hal On Sep 12, 2019, at 12:30 PM, Daan Sprenkels via llvm-dev <llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>> wrote: PS. Perhaps, would there be interest to add such a feature to LLVM? I found this repository on GitHub[2], adding a `__builtin_ct_choose` intrinsic to clang. But as far as I know, this has never been up...

...hat they continually run and that checks the specific instruction stream produced by the compiler. Given the current state, that's about the only reliable approach I know of. > > -Chandler > > > -Hal > > > >> >>> On Sep 12, 2019, at 12:30 PM, Daan Sprenkels via llvm-dev <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: >>> >>> PS. Perhaps, would there be interest to add such a feature to LLVM? >>> I found this repository on GitHub[2], adding a `__builtin_ct_choose` >>> intrinsic t...