[PATCH] D97475: [RISCV] Support EXTRACT_SUBVECTOR on vector masks

[Fraser Cormack via Phabricator via llvm-commits]

frasercrmck created this revision.
frasercrmck added reviewers: craig.topper, evandro, rogfer01, HsiangKai, khchen, arcbbb.
Herald added subscribers: vkmr, luismarques, apazos, sameer.abuasal, s.egerton, Jim, benna, psnobl, jocewei, PkmX, the_o, brucehoult, MartinMosbeck, edward-jones, zzheng, jrtc27, shiva0217, kito-cheng, niosHD, sabuasal, simoncook, johnrusso, rbar, asb, hiraditya.
frasercrmck requested review of this revision.
Herald added subscribers: llvm-commits, MaskRay.
Herald added a project: LLVM.

This patch adds support for extracting subvectors from vector masks.
This can be either extracting a scalable vector from another, or a fixed-length
vector from a fixed-length or scalable vector.

Since RVV lacks a way to slide vector masks down on an element-wise
basis and we don't know the true length of the vector registers, in many
cases we must resort to using equivalently-sized i8 vectors to perform
the operation. When this is not possible we fall back and extend to a
suitable i8 vector.

Support was also added for fixed-length truncation to mask types.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D97475

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/test/CodeGen/RISCV/rvv/extract-subvector.ll
  llvm/test/CodeGen/RISCV/rvv/fixed-vectors-extract-subvector.ll

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D97475.326394.patch
Type: text/x-patch
Size: 21393 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20210225/3390e2cc/attachment-0001.bin>