[all-commits] [llvm/llvm-project] 3b18d4: [SLP]Improved reduction cost/codegen

Alexey Bataev via All-commits all-commits at lists.llvm.org
Fri Feb 14 11:04:13 PST 2025


  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3b18d47ecbaba4e519ebf0d1bc134a404a56a9da
      https://github.com/llvm/llvm-project/commit/3b18d47ecbaba4e519ebf0d1bc134a404a56a9da
  Author: Alexey Bataev <a.bataev at outlook.com>
  Date:   2025-02-14 (Fri, 14 Feb 2025)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    M llvm/test/Transforms/SLPVectorizer/AArch64/InstructionsState-is-invalid-0.ll
    M llvm/test/Transforms/SLPVectorizer/AArch64/reduce-fadd.ll
    M llvm/test/Transforms/SLPVectorizer/AMDGPU/reduction.ll
    M llvm/test/Transforms/SLPVectorizer/RISCV/horizontal-list.ll
    M llvm/test/Transforms/SLPVectorizer/RISCV/reductions.ll
    M llvm/test/Transforms/SLPVectorizer/X86/bool-mask.ll
    M llvm/test/Transforms/SLPVectorizer/X86/ctpop-non-power-of-2-reduction.ll
    M llvm/test/Transforms/SLPVectorizer/X86/external-used-across-reductions.ll
    M llvm/test/Transforms/SLPVectorizer/X86/extract-scalar-from-undef.ll
    M llvm/test/Transforms/SLPVectorizer/X86/extractelemets-extended-by-poison.ll
    M llvm/test/Transforms/SLPVectorizer/X86/horizontal-list.ll
    M llvm/test/Transforms/SLPVectorizer/X86/horizontal-minmax.ll
    M llvm/test/Transforms/SLPVectorizer/X86/malformed_phis.ll
    M llvm/test/Transforms/SLPVectorizer/X86/multi-tracked-reduced-value.ll
    M llvm/test/Transforms/SLPVectorizer/X86/phi-node-reshuffled-part.ll
    M llvm/test/Transforms/SLPVectorizer/X86/reduced-val-extracted-and-externally-used.ll
    M llvm/test/Transforms/SLPVectorizer/X86/reduced-value-vectorized-later.ll
    M llvm/test/Transforms/SLPVectorizer/X86/reduction-extracted-value.ll
    M llvm/test/Transforms/SLPVectorizer/X86/revectorized_rdx_crash.ll
    M llvm/test/Transforms/SLPVectorizer/X86/undef_vect.ll
    M llvm/test/Transforms/SLPVectorizer/partial-register-extract.ll
    M llvm/test/Transforms/SLPVectorizer/reduction-modified-values.ll
    M llvm/test/Transforms/SLPVectorizer/scalarization-overhead.ll

  Log Message:
  -----------
  [SLP]Improved reduction cost/codegen

SLP vectorizer is able to combine several reductions from the list of
(potentially) reduced values with the different opcodes/values kind.
Currently, these reductions are handled independently of each other. But
instead the compiler can combine them into wide vector operations and
then perform only single reduction.
E.g, if the SLP vectorizer emits currently something like:
```
%r1 = reduce.add(<4 x i32> %v1)
%r2 = reduce.add(<4 x i32> %v2)
%r = add i32 %r1, %r2
```

it can be emitted as:
```
%v = add <4 x i32> %v1, %v2
%r = reduce.add(<4 x i32> %v)
```

It allows to improve the performance in some cases.

AVX512, -O3+LTO
Metric: size..text

Program                                                                                           size..text
                                                                                                  results     results0    diff
                      test-suite :: SingleSource/Benchmarks/Shootout-C++/Shootout-C++-matrix.test     4553.00     4615.00  1.4%
                                 test-suite :: SingleSource/Benchmarks/Adobe-C++/loop_unroll.test   412708.00   416820.00  1.0%
        test-suite :: SingleSource/UnitTests/Vector/AVX512BWVL/Vector-AVX512BWVL-mask_set_bw.test    12901.00    12981.00  0.6%
                        test-suite :: MultiSource/Benchmarks/FreeBench/fourinarow/fourinarow.test    22717.00    22813.00  0.4%
                             test-suite :: MultiSource/Benchmarks/mediabench/gsm/toast/toast.test    39722.00    39850.00  0.3%
                      test-suite :: MultiSource/Benchmarks/MiBench/telecomm-gsm/telecomm-gsm.test    39725.00    39853.00  0.3%
test-suite :: SingleSource/Regression/C/gcc-c-torture/execute/GCC-C-execute-builtin-bitops-1.test    15918.00    15967.00  0.3%
                                       test-suite :: External/SPEC/CFP2006/433.milc/433.milc.test   155491.00   155587.00  0.1%
                                     test-suite :: MicroBenchmarks/ImageProcessing/Blur/blur.test   227894.00   227942.00  0.0%
                                    test-suite :: MultiSource/Benchmarks/7zip/7zip-benchmark.test  1062188.00  1062364.00  0.0%
                                test-suite :: External/SPEC/CINT2006/464.h264ref/464.h264ref.test   793672.00   793720.00  0.0%
                              test-suite :: External/SPEC/CINT2017rate/525.x264_r/525.x264_r.test   657371.00   657403.00  0.0%
                             test-suite :: External/SPEC/CINT2017speed/625.x264_s/625.x264_s.test   657371.00   657403.00  0.0%
                   test-suite :: External/SPEC/CINT2017speed/600.perlbench_s/600.perlbench_s.test  2074917.00  2074933.00  0.0%
                    test-suite :: External/SPEC/CINT2017rate/500.perlbench_r/500.perlbench_r.test  2074917.00  2074933.00  0.0%
                                     test-suite :: MultiSource/Applications/JM/lencod/lencod.test   855219.00   855203.00 -0.0%

Benchmarks/Shootout-C++ - same transformed reduction
Adobe-C++/loop_unroll - same transformed reductions, new vector code
AVX512BWVL/Vector-AVX512BWVL-mask_set_bw - same transformed reductions
FreeBench/fourinarow - same transformed reductions
MiBench/telecomm-gsm - same transformed reductions
execute/GCC-C-execute-builtin-bitops-1 - same transformed reductions
CFP2006/433.milc - better vector code, several x i64 reductions + trunc
to i32 gets trunced to x i32 reductions
ImageProcessing/Blur - same transformed reductions
Benchmarks/7zip - same transformed reductions, extra 4 x vectorization
CINT2006/464.h264ref - same transformed reductions
CINT2017rate/525.x264_r
CINT2017speed/625.x264_s - same transformed reductions
CINT2017speed/600.perlbench_s
CINT2017rate/500.perlbench_r - transformed same reduction
JM/lencod - extra 4 x vectorization

RISC-V, SiFive-p670, -O3+LTO

Metric: size..text

Program                                                                                           size..text
                                                                                                  results    results0   diff
test-suite :: SingleSource/Regression/C/gcc-c-torture/execute/GCC-C-execute-builtin-bitops-1.test    8990.00    9514.00   5.8%
                                test-suite :: External/SPEC/CINT2006/464.h264ref/464.h264ref.test  588504.00  588488.00  -0.0%
                    test-suite :: MultiSource/Benchmarks/MiBench/consumer-lame/consumer-lame.test  147464.00  147440.00  -0.0%
              test-suite :: MultiSource/Benchmarks/MiBench/automotive-susan/automotive-susan.test   21496.00   21492.00  -0.0%
                                     test-suite :: MicroBenchmarks/ImageProcessing/Blur/blur.test  165420.00  165372.00  -0.0%
                                    test-suite :: MultiSource/Benchmarks/7zip/7zip-benchmark.test  843928.00  843648.00  -0.0%
                                    test-suite :: External/SPEC/CINT2006/458.sjeng/458.sjeng.test  100712.00  100672.00  -0.0%
                      test-suite :: MultiSource/Benchmarks/MiBench/telecomm-gsm/telecomm-gsm.test   24384.00   24336.00  -0.2%
                             test-suite :: MultiSource/Benchmarks/mediabench/gsm/toast/toast.test   24380.00   24332.00  -0.2%
             test-suite :: SingleSource/UnitTests/Vectorizer/VPlanNativePath/outer-loop-vect.test   10348.00   10316.00  -0.3%
                                 test-suite :: SingleSource/Benchmarks/Adobe-C++/loop_unroll.test  221304.00  220480.00  -0.4%
                      test-suite :: SingleSource/Benchmarks/Shootout-C++/Shootout-C++-matrix.test    3750.00    3736.00  -0.4%
                            test-suite :: SingleSource/Regression/C/Regression-C-DuffsDevice.test     678.00     370.00 -45.4%

execute/GCC-C-execute-builtin-bitops-1 - extra 4 x reductions, same
transformed reductions
CINT2006/464.h264ref - extra 4 x reductions, same transformed reductions
MiBench/consumer-lame - 2 4 x i1 merged to 8 x i1 reductions (bitcast + ctpop)
MiBench/automotive-susan - same transformed reductions
ImageProcessing/Blur - same transformed reductions
Benchmarks/7zip - same transformed reductions
CINT2006/458.sjeng - 2 4 x i1 merged to 8 x i1 reductions (bitcast + ctpop)
MiBench/telecomm-gsm - same transformed reductions
Benchmarks/mediabench - same transformed reductions
Vectorizer/VPlanNativePath - same transformed reductions
Adobe-C++/loop_unroll - extra 4 x reductions, same transformed reductions
Benchmarks/Shootout-C++ - extra 4 x reductions, same transformed reductions
Regression/C/Regression-C-DuffsDevice - same transformed reductions

Reviewers: hiraditya, topperc, preames

Pull Request: https://github.com/llvm/llvm-project/pull/118293



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