[PATCH] D21530: Moving loop vectorization pass before loop-unroller.

[Laxman Sole via llvm-commits]

laxmansole created this revision.
laxmansole added reviewers: t.p.northover, hfinkel, mehdi_amini.
laxmansole added subscribers: llvm-commits, hiraditya, sebpop, evandro.
Herald added subscribers: mehdi_amini, aemerson.

Loop with constant trip count get unrolled first due to which it does not get vectorized. Hence moving loop-vectorizer before loop unroller. It will fix the following bugs with 2-5% performance improvement on 300.twolf, 253.perlbmk, 256.bzip2, 176.gcc and 1-2% regression on 175.vpr and 252.eon while running on AArch64:

https://llvm.org/bugs/show_bug.cgi?id=25748
https://llvm.org/bugs/show_bug.cgi?id=28090

Benchmarks                                                                        %improvement (lower is better) compared to llvm-trunk(4dfe58af9)
External/SPEC/CFP2000/177.mesa/177.mesa_secs                         0.51
External/SPEC/CFP2000/179.art/179.art_secs                                 0.73
External/SPEC/CFP2000/183.equake/183.equake_secs                  0.72
External/SPEC/CFP2000/188.ammp/188.ammp_secs                     0.14
External/SPEC/CINT2000/164.gzip/164.gzip_secs                         -1.48
External/SPEC/CINT2000/175.vpr/175.vpr_secs                             2.04
External/SPEC/CINT2000/176.gcc/176.gcc_secs                            -2.18
External/SPEC/CINT2000/181.mcf/181.mcf_secs                           -0.54
External/SPEC/CINT2000/186.crafty/186.crafty_secs                      0.34
External/SPEC/CINT2000/197.parser/197.parser_secs                    0.61
External/SPEC/CINT2000/252.eon/252.eon_secs                            1.80
External/SPEC/CINT2000/253.perlbmk/253.perlbmk_secs            -3.65
External/SPEC/CINT2000/254.gap/254.gap_secs                           -0.91
External/SPEC/CINT2000/255.vortex/255.vortex_secs                    0.21
External/SPEC/CINT2000/256.bzip2/256.bzip2_secs                     -3.35
External/SPEC/CINT2000/300.twolf/300.twolf_secs                       -5.65

Worked in collaboration with Aditya Kumar and Sebastian Pop.

http://reviews.llvm.org/D21530

Files:
  llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
  llvm/test/Other/pass-pipelines.ll
  llvm/test/Transforms/LoopVectorize/LoopWithConstTripCount1.ll
  llvm/test/Transforms/LoopVectorize/LoopWithConstTripCount2.ll

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D21530.61285.patch
Type: text/x-patch
Size: 6066 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20160620/9f274844/attachment.bin>