[all-commits] [llvm/llvm-project] d8d1cc: [SLP] Also try to vectorize incoming values of PHIs .

Florian Hahn via All-commits all-commits at lists.llvm.org
Fri Nov 6 04:59:17 PST 2020 

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: d8d1cc647d87b453a2dbb8242c75e3bccc443bbd
      https://github.com/llvm/llvm-project/commit/d8d1cc647d87b453a2dbb8242c75e3bccc443bbd
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2020-11-06 (Fri, 06 Nov 2020)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    M llvm/test/Transforms/SLPVectorizer/X86/horizontal.ll

  Log Message:
  -----------
  [SLP] Also try to vectorize incoming values of PHIs .

Currently we do not consider incoming values of PHIs as roots for SLP
vectorization. This means we miss scenarios like the one in the test
case and PR47670.

It appears quite straight-forward to consider incoming values of PHIs as
roots for vectorization, but I might be missing something that makes
this problematic.

In terms of vectorized instructions, this applies to quite a few
benchmarks across MultiSource/SPEC2000/SPEC2006 on X86 with -O3 -flto

    Same hash: 185 (filtered out)
    Remaining: 52
    Metric: SLP.NumVectorInstructions

    Program                                        base    patch   diff
     test-suite...ProxyApps-C++/HPCCG/HPCCG.test     9.00   27.00  200.0%
     test-suite...C/CFP2000/179.art/179.art.test     8.00   22.00  175.0%
     test-suite...T2006/458.sjeng/458.sjeng.test    14.00   30.00  114.3%
     test-suite...ce/Benchmarks/PAQ8p/paq8p.test    11.00   18.00  63.6%
     test-suite...s/FreeBench/neural/neural.test    12.00   18.00  50.0%
     test-suite...rimaran/enc-3des/enc-3des.test    65.00   95.00  46.2%
     test-suite...006/450.soplex/450.soplex.test    63.00   89.00  41.3%
     test-suite...ProxyApps-C++/CLAMR/CLAMR.test   177.00  250.00  41.2%
     test-suite...nchmarks/McCat/18-imp/imp.test    13.00   18.00  38.5%
     test-suite.../Applications/sgefa/sgefa.test    26.00   35.00  34.6%
     test-suite...pplications/oggenc/oggenc.test   100.00  133.00  33.0%
     test-suite...6/482.sphinx3/482.sphinx3.test   103.00  134.00  30.1%
     test-suite...oxyApps-C++/miniFE/miniFE.test   169.00  213.00  26.0%
     test-suite.../Benchmarks/Olden/tsp/tsp.test    59.00   73.00  23.7%
     test-suite...TimberWolfMC/timberwolfmc.test   503.00  622.00  23.7%
     test-suite...T2006/456.hmmer/456.hmmer.test    65.00   79.00  21.5%
     test-suite...libquantum/462.libquantum.test    58.00   68.00  17.2%
     test-suite...ternal/HMMER/hmmcalibrate.test    84.00   98.00  16.7%
     test-suite...ications/JM/ldecod/ldecod.test   351.00  401.00  14.2%
     test-suite...arks/VersaBench/dbms/dbms.test    52.00   57.00   9.6%
     test-suite...ce/Benchmarks/Olden/bh/bh.test   118.00  128.00   8.5%
     test-suite.../Benchmarks/Bullet/bullet.test   6355.00 6880.00  8.3%
     test-suite...nsumer-lame/consumer-lame.test   480.00  519.00   8.1%
     test-suite...000/183.equake/183.equake.test   226.00  244.00   8.0%
     test-suite...chmarks/Olden/power/power.test   105.00  113.00   7.6%
     test-suite...6/471.omnetpp/471.omnetpp.test    92.00   99.00   7.6%
     test-suite...ications/JM/lencod/lencod.test   1173.00 1261.00  7.5%
     test-suite...0/253.perlbmk/253.perlbmk.test    55.00   59.00   7.3%
     test-suite...oxyApps-C/miniAMR/miniAMR.test    92.00   98.00   6.5%
     test-suite...chmarks/MallocBench/gs/gs.test   446.00  473.00   6.1%
     test-suite.../CINT2006/403.gcc/403.gcc.test   464.00  491.00   5.8%
     test-suite...6/464.h264ref/464.h264ref.test   998.00  1055.00  5.7%
     test-suite...006/453.povray/453.povray.test   5711.00 6007.00  5.2%
     test-suite...FreeBench/distray/distray.test   102.00  107.00   4.9%
     test-suite...:: External/Povray/povray.test   4184.00 4378.00  4.6%
     test-suite...DOE-ProxyApps-C/CoMD/CoMD.test   112.00  117.00   4.5%
     test-suite...T2006/445.gobmk/445.gobmk.test   104.00  108.00   3.8%
     test-suite...CI_Purple/SMG2000/smg2000.test   789.00  819.00   3.8%
     test-suite...yApps-C++/PENNANT/PENNANT.test   233.00  241.00   3.4%
     test-suite...marks/7zip/7zip-benchmark.test   417.00  428.00   2.6%
     test-suite...arks/mafft/pairlocalalign.test   627.00  643.00   2.6%
     test-suite.../Benchmarks/nbench/nbench.test   259.00  265.00   2.3%
     test-suite...006/447.dealII/447.dealII.test   4641.00 4732.00  2.0%
     test-suite...lications/ClamAV/clamscan.test   106.00  108.00   1.9%
     test-suite...CFP2000/177.mesa/177.mesa.test   1639.00 1664.00  1.5%
     test-suite...oxyApps-C/RSBench/rsbench.test    66.00   65.00  -1.5%
     test-suite.../CINT2000/252.eon/252.eon.test   3416.00 3444.00  0.8%
     test-suite...CFP2000/188.ammp/188.ammp.test   1846.00 1861.00  0.8%
     test-suite.../CINT2000/176.gcc/176.gcc.test   152.00  153.00   0.7%
     test-suite...CFP2006/444.namd/444.namd.test   3528.00 3544.00  0.5%
     test-suite...T2006/473.astar/473.astar.test    98.00   98.00   0.0%
     test-suite...frame_layout/frame_layout.test    NaN     39.00   nan%

On ARM64, there appears to be a slight regression on SPEC2006, which
might be interesting to investigate:

   test-suite...T2006/473.astar/473.astar.test   0.9%

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D88735

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