[Bug target/113600] [14 regression] 525.x264_r run-time regresses by 8% with PGO -Ofast -march=znver4

[jamborm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113600

--- Comment #4 from Martin Jambor <jamborm at gcc dot gnu.org> ---
(In reply to Hongtao Liu from comment #2)
> A patch is posted at
> https://gcc.gnu.org/pipermail/gcc-patches/2023-December/640276.html
> 
> Would you give a try to see if it fixes the regression, I don't currently
> have a znver4 machine for testing.

Unfortunately it does not.

(In reply to Richard Biener from comment #3)
> I think we need to figure out what exactly gets slower (and hope it's not
> scattered all over the place)

I have collected some profiles:

r14-5602-ge6269bb69c0734

# Samples: 516K of event 'cycles:u'
# Event count (approx.): 468008188417
# Overhead       Samples  Command          Shared Object                       
  Symbol                                           
# ........  ............  ............... 
..................................... 
.................................................
#
    13.55%         69886  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] mc_chroma
    11.05%         57017  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_satd_16x16
     9.24%         47693  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_satd_8x8
     8.67%         44733  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] get_ref
     4.84%         24984  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] sub16x16_dct
     4.16%         21484  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_me_search_ref
     3.30%         17033  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_hadamard_ac_16x16
     2.28%         11770  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_satd_4x4
     2.10%         10824  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] quant_trellis_cabac
     2.07%         10694  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] hpel_filter
     2.05%         10616  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] sub8x8_dct
     1.86%          9593  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] refine_subpel
     1.70%          8788  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] quant_4x4
     1.57%          8077  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_sad_16x16
     1.16%          6324  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] frame_init_lowres_core
     1.14%          5867  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_sa8d_8x8
     1.11%          5738  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_cabac_encode_decision_c
     1.08%          5736  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_var_16x16



r14-5603-g2b59e2b4dff421

# Samples: 550K of event 'cycles:u'
# Event count (approx.): 498834737657
# Overhead       Samples  Command          Shared Object                       
  Symbol                                           
# ........  ............  ............... 
..................................... 
.................................................
#
    18.21%        100151  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_satd_16x16
    12.37%         68006  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] mc_chroma
     8.51%         46815  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_satd_8x8
     7.56%         41560  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] get_ref
     4.53%         24901  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] sub16x16_dct
     3.92%         21561  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_me_search_ref
     3.08%         16963  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_hadamard_ac_16x16
     2.41%         13239  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_satd_4x4
     1.99%         10931  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] quant_trellis_cabac
     1.96%         10801  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] hpel_filter
     1.95%         10764  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] sub8x8_dct
     1.56%          8587  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] quant_4x4
     1.49%          8166  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] refine_subpel
     1.48%          8124  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_sad_16x16
     1.09%          6328  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] frame_init_lowres_core
     1.07%          5901  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_pixel_sa8d_8x8
     1.04%          5703  x264_r_peak.min 
x264_r_peak.mine-pgo-Ofast-native-m64  [.] x264_cabac_encode_decision_c