simoll marked 4 inline comments as done. simoll added inline comments.
================ Comment at: clang/docs/LanguageExtensions.rst:492 + +The memory representation of a boolean vector is the smallest fitting +power-of-two integer. The alignment is the alignment of that integer type. This ---------------- rsandifo-arm wrote: > simoll wrote: > > rsandifo-arm wrote: > > > It might be worth clarifying this. With the alignment referring > > > specifically to “integer type”, I wasn't sure what something like: > > > > > > bool __attribute__((vector_size(256))) > > > > > > would mean on targets that don't provide 256-byte integer types. Is the > > > type still 256-byte aligned? > > Not exactly: It is the alignment of the corresponding integer type. > > For example the following C code: > > > > typedef bool bool256 __attribute__((vector_size(256))); > > bool256 P; > > > > gives you (x86_64 host, no machine flags specified): > > > > %P = alloca i2048, align 32 > I guess my point is pedantic, but what I meant was: does the concept of “the > corresponding integer type” necessarily exist at the C/C++ level? E.g. how > would you end up with the same LLVM IR statement using C integer types > instead of vectors? > > My worry was that “the alignment of the corresponding integer type” would > only be meaningful to the user if they could identify what the corresponding > (C) integer type actually was, and be able to determine its alignment that > way. > To be honest, i hadn't given alignment much thought before. Actually, i am not too happy about bringing in integer types here. I guess it's sensible to do no different than for the other vector types: take the size rounded up to the next power-ot-two capped by the target's maximum vector alignment. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D81083/new/ https://reviews.llvm.org/D81083 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
