ctetreau added inline comments.
================ Comment at: llvm/include/llvm/IR/IRBuilder.h:2544 + SmallVector<int, 16> IntMask; + ShuffleVectorInst::getShuffleMask(cast<Constant>(Mask), IntMask); + return CreateShuffleVector(V1, V2, IntMask, Name); ---------------- spatel wrote: > Add an assert that Mask isa<Constant> ? cast<T> already does this assert. ================ Comment at: llvm/include/llvm/IR/IRBuilder.h:2551 + SmallVector<int, 16> IntMask; + IntMask.assign(Mask.begin(), Mask.end()); + return CreateShuffleVector(V1, V2, IntMask, Name); ---------------- [0 .. uint32_MAX] is wider than [0 .. int_MAX]. Assert the values are in range somehow? ================ Comment at: llvm/include/llvm/IR/Instructions.h:1985-1986 /// +/// The shuffle mask operand specifies, for each element of the result vector, +/// which element of the two input vectors the result element gets. The +/// shuffle mask is represented as an array of integers. Positive integers ---------------- spatel wrote: > This reads awkwardly to me (if you agree, we can update the LangRef too). > How about: > "For each element of the result vector, the shuffle mask selects an element > from one of the input vectors to copy to the result. Non-negative elements in > the mask represent an index into the concatenated pair of input vectors. > UndefMaskElem (-1) specifies that the result element is undefined." I also found the wording of the description of shufflevector in the language ref confusing. Since this description seems to be related I thought it worth mentioning. It's unclear to me how the values specify vector inputs. I assume for two vectors <4 x 18>, that the mask <3, 4, 5, 6> takes the last element of the first vector, and the first three elements of the second vector, but this isn't explicitly stated anywhere. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D72467/new/ https://reviews.llvm.org/D72467 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
