On Wed, Jan 15, 2025 at 1:54 PM Kyrylo Tkachov <ktkachov@xxxxxxxxxx> wrote: > > Hi David, > > > On 15 Jan 2025, at 13:33, David Aldrich via Gcc-help <gcc-help@xxxxxxxxxxx> wrote: > > > > Hi > > > > The gcc Arm compiler aarch64-linux-gnu (v14) provides the following > > Arm intrinsics header file: > > > > \usr\lib\gcc\aarch64-linux-gnu\14\include\arm_sve.h > > > > However, this header file uses a pragma to generate the definitions: > > > > /* NOTE: This implementation of arm_sve.h is intentionally short. It does > > not define the SVE types and intrinsic functions directly in C and C++ > > code, but instead uses the following pragma to tell GCC to insert the > > necessary type and function definitions itself. The net effect is the > > same, and the file is a complete implementation of arm_sve.h. */ > > #pragma GCC aarch64 "arm_sve.h" > > > > I don't understand how this works. > > > > The idea is that rather than implementing every ACLE intrinsic as a wrapper around an builtin, annotated with attributes like always_inline etc the compiler injects > the necessary intrinsic definitions directly into the language when it encounters this aarch64-specific pragma. > This has a number of advantages, among others: > * It avoids having to parse a large regular .h file during compilation > * It allows the compiler to handle some of the more elaborate features of SVE intrinsics such as overloading and type deduction during name resolution. > * It allows for more powerful custom validation of intrinsic arguments (like enforcing strict compile-time literal arguments for vector lanes) and more helpful error message > > > I would like to inspect the actual definitions of the intrinsics. Is > > it possible to view the actual definitions? > > > > The downside is there’s no single self-contained file that interested readers can look at. > You can find the code that creates these definitions for SVE in the GCC source in the files named aarch64-sve-builtins-*.cc under the gcc/config/aarch64 subdirectory: > https://gcc.gnu.org/git/?p=gcc.git;a=tree;f=gcc/config/aarch64;h=7f0aea8187549eefa9c3c6d046a3f56183dc2a69;hb=HEAD > > Thanks, > Kyrill > Hi Kyrill Thanks very much for your explanation. I looked at aarch64-sve-builtins-*.cc but don't think it will help me. Unfortunately, another downside is that IDE assistance such as Microsoft Visual Studio's Intellisense can't provide help with these functions, unless the internal compiler understands how to generate the definitions, which is unlikely. Best regards David
