[all-commits] [llvm/llvm-project] ce6e4f: [RISCV] Use fractional LMULs for fixed length type...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ce6e4f27dd72f834502f47176d84869a1f509d7b
      https://github.com/llvm/llvm-project/commit/ce6e4f27dd72f834502f47176d84869a1f509d7b
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2021-05-11 (Tue, 11 May 2021)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-bitcast.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-bitreverse.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-calling-conv.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-extload-truncstore.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-extract-i1.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-extract-subvector.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-bitcast.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-buildvec.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-conv.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-setcc.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-shuffles.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp2i.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-i2fp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-insert-subvector.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-buildvec.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-exttrunc.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-setcc.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-splat.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-mask-buildvec.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-mask-load-store.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-mask-logic.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-mask-splat.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-gather.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-load-fp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-load-int.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-scatter.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-store-fp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-store-int.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-fp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-int.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-select-fp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-select-int.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-stepvector-rv32.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-stepvector-rv64.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vadd-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vand-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vdiv-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vdivu-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vfmax.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vfmin.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vmul-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vor-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vreductions-mask.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vrem-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vremu-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vrsub-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vselect.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vshl-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vsra-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vsrl-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vsub-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vxor-vp.ll
    M llvm/test/CodeGen/RISCV/srem-seteq-illegal-types.ll
    M llvm/test/CodeGen/RISCV/urem-seteq-illegal-types.ll

  Log Message:
  -----------
  [RISCV] Use fractional LMULs for fixed length types smaller than riscv-v-vector-bits-min.

My thought process is that if v2i64 is an LMUL=1 type then v2i32
should be an LMUL=1/2 type. We limit the fractional LMUL so that
SEW=64 clips to LMUL=1, SEW=32 clips to LMUL=1/2, etc. This
ensures there's always a fractional LMUL available to truncate a type.
This does reduce the number of vsetvlis in some cases.

Some tests increase vsetvlis because the best container type for a
mask type is dependent on the LMUL+SEW that the mask was produced
from, but you can't tell that from the type. I think this is
something we need to solve this in the machine IR when optimizing
vsetvlis.

Reviewed By: frasercrmck

Differential Revision: https://reviews.llvm.org/D101215