[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
Welcome to the LLVM project!
This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.
The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.
Other components include: the libc++ C++ standard library, the LLD linker, and more.
Consult the Getting Started with LLVM page for information on building and running LLVM.
For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.
Join the LLVM Discourse forums, Discord chat, LLVM Office Hours or Regular sync-ups.
The LLVM project has adopted a code of conduct for participants to all modes of communication within the project.