On Fri, 27 Oct 2023 08:04:47 GMT, Xiaohong Gong <xg...@openjdk.org> wrote:
>> For x86 backend implementation we emit a gather loop hence index species is >> not used for sub-word, I am performing the index out of bound in a loop >> which operate a max integer vector granularity supported by target. >> https://github.com/openjdk/jdk/pull/16354/files#diff-13cc2d6ec18e487ddae05cda671bdb6bb7ffd42ff7bc51a2e00c8c5e622bd55dR3641 >> >> Because there is cap on max integral vector size, thus for targets >> supporting direct sub-word gather instruction will have to emit an >> instruction sequence comprising of partial indexMap loads into integral >> vectors and issue multiple gather operations. > > I see, thanks for the explanation! It's different from SVE, which the index > should be an int vector with the same length of the target vector. We have > to generate the index vectors. So the array length check to the given index > map is necessary in java side. Intrinsic still receive the indexArray and corresponding species with matching lane count OR maximally supported integral species otherwise. Due to lane size differences b/w sub-word and integer it may never be possible to have compatible species. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/16354#discussion_r1375524154
