Anastasia added a comment. In https://reviews.llvm.org/D30810#699827, @jaykang10 wrote:
> In https://reviews.llvm.org/D30810#699695, @bruno wrote: > > > Hi JinGu, > > > > I just read the discussion on cfe-dev, some comments: > > > > > My colleague and I are implementing a transformation pass between LLVM IR > > > and another IR and we want to keep the 3-component vector types in our > > > target IR > > > > Why can't you go back through the shuffle to find out that it comes from a > > vec3 -> vec4 transformation? Adding a flag here just for that seems very > > odd. > > > Hi Bruno, > > Thanks for your comment. We have a pass to undo the vec4 to vec3. I wondered > why clang generates the vec4 for vec3 load/store. As you can see the comment > on clang's code, they are generated for better performance. I had a questions > at this point. clang should consider vector load/store aligned by 4 > regardless of target??? llvm's codegen could handle vec3 according to > targets' vector load/store with their alignment. I agree the flag looks odd > but I was concerned some llvm's targets depend on the vec4 so I suggested to > add the flag. If I missed something, please let me know. I think doing this transformation in a frontend was not the best choice because we are losing the source information too early. But some targets can offer a better support for vec3 natively than converting to vec4. Regarding the option, I am wondering whether adding this as a part of TargetInfo would be a better solution. Although, I don't think any currently available upstream targets support this. https://reviews.llvm.org/D30810 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
