[PATCH] D98969: [RISCV] Further optimize BUILD_VECTORs with repeated elements

[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.
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This patch builds upon the initial BUILD_VECTOR work introduced in
D98700 <https://reviews.llvm.org/D98700>. It further optimizes the lowering of BUILD_VECTOR by using
VSELECT operations to effectively insert repeated elements into the
vector with relatively few instructions. This allows us to optimize more
BUILD_VECTORs without significantly increasing the size of the generated
code.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D98969

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/test/CodeGen/RISCV/rvv/fixed-vectors-bitreverse.ll
  llvm/test/CodeGen/RISCV/rvv/fixed-vectors-ctpop.ll
  llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-buildvec.ll
  llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-splat.ll
  llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int.ll

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