Disable slp in loop vectorizer when cost model is very-cheap.
Performance impact for the commit with option:
-march=x86-64 -O2 -ftree-vectorize -fvect-cost-model=very-cheap
SPEC2017 fprate
503.bwaves_r BuildSame
507.cactuBSSN_r -0.04
508.namd_r 0.14
510.parest_r -0.54
511.povray_r 0.10
519.lbm_r BuildSame
521.wrf_r 0.64
526.blender_r -0.32
527.cam4_r 0.17
538.imagick_r 0.09
544.nab_r BuildSame
549.fotonik3d_r BuildSame
554.roms_r BuildSame
997.specrand_fr -0.09
Geometric mean: 0.02
SPEC2017 intrate
500.perlbench_r 0.26
502.gcc_r 0.21
505.mcf_r -0.09
520.omnetpp_r BuildSame
523.xalancbmk_r BuildSame
525.x264_r -0.41
531.deepsjeng_r BuildSame
541.leela_r 0.13
548.exchange2_r BuildSame
557.xz_r BuildSame
999.specrand_ir BuildSame
Geometric mean: 0.02
EEMBC: no regression, only improvement or build the same, the below is
improved benchmarks.
mp2decoddata1 7.59
mp2decoddata2 31.80
mp2decoddata3 12.15
mp2decoddata4 11.16
mp2decoddata5 11.19
mp2decoddata1 7.06
mp2decoddata2 24.12
mp2decoddata3 10.83
mp2decoddata4 10.04
mp2decoddata5 10.07
gcc/ChangeLog:
PR tree-optimization/100089
* tree-vectorizer.c (try_vectorize_loop_1): Disable slp in
loop vectorizer when cost model is very-cheap.