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8506d96115
The cost of an interleaved access was only implemented for AVX512. For other X86 targets an overly conservative Base cost was returned, resulting in avoiding vectorization where it is actually profitable to vectorize. This patch starts to add costs for AVX2 for most prominent cases of interleaved accesses (stride 3,4 chars, for now). Note1: Improvements of up to ~4x were observed in some of EEMBC's rgb workloads; There is also a known issue of 15-30% degradations on some of these workloads, associated with an interleaved access followed by type promotion/widening; the resulting shuffle sequence is currently inefficient and will be improved by a series of patches that extend the X86InterleavedAccess pass (such as D34601 and more to follow). Note 2: The costs in this patch do not reflect port pressure penalties which can be very dominant in the case of interleaved accesses since most of the shuffle operations are restricted to a single port. Further tuning, that may incorporate these considerations, will be done on top of the upcoming improved shuffle sequences (that is, along with the abovementioned work to extend X86InterleavedAccess pass). Differential Revision: https://reviews.llvm.org/D34023 llvm-svn: 306238