https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110015
Bug ID: 110015
Summary: openjpeg is slower when built with gcc13 compared to
clang16
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: hubicka at gcc dot gnu.org
Target Milestone: ---
I tried to reproduce openjpeg benchmarks from Phoronix
https://www.phoronix.com/review/gcc13-clang16-raptorlake/5
On zen3 hardware I get 42607ms for clang build and 45702ms for gcc build that
is a 7% difference (Phoronix reports 10% on RaptorLake)
perf of clang build:
88.64% opj_t1_cblk_encode_processor
6.68% opj_dwt_encode_and_deinterleave_v
1.30% opj_dwt_encode_and_deinterleave_h_one_row
opj_t1_cblk_encode_processor is huge with no obvious hot spots.
perf of gcc build:
70.36% opj_t1_cblk_encode_processor
16.12% opj_t1_enc_refpass.lto_priv.0
3.88% opj_dwt_encode_and_deinterleave_v
2.46% pj_dwt_fetch_cols_vertical_pass
2.35% opj_mqc_byteout
So we apparently inline less even at -O3
