jaykang10 added a comment. In https://reviews.llvm.org/D30810#701861, @Anastasia wrote:
> I don't think there is anything wrong with the generation of vec3->vec4 in > Clang. I believe the motivation for this was the OpenCL spec treating vec3 as > vec4 aligned type (see section 6.1.5: > https://www.khronos.org/registry/OpenCL/specs/opencl-2.0-openclc.pdf#12). So > in terms of memory layout vec3 wouldn't be any different to vec4. But in > terms of operations (including loads/stores) there can be potential gain from > not handling the 4th element. This can be exploited by some targets. I think > generating the vec3 from the frontend would be a better choice in the first > place. Because backend can decide how to handle this. Including for > architectures with no SIMD support it would just generate 3 separate > loads/stores. Right now it seems that it will be forced to generate 4 > loads/stores. > > But considering that transformation to vec4 has been the default > implementation for quite a while in the frontend, I think we would need a > stronger motivation for switching to original vec3. So current approach with > a special flag for preserving vec3 should be good enough to fit all needs. Thank you, Anastasia. Can we go ahead and commit this patch? https://reviews.llvm.org/D30810 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
