[Bug target/109811] libjxl 0.7 is a lot slower in GCC 13.1 vs Clang 16

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109811

--- Comment #18 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
I made a typo:

Mainline with -O2 -flto  -march=native run manually since build machinery patch
is needed
        23.03
        22.85
        23.04

Should be 
Mainline with -O3 -flto  -march=native run manually since build machinery patch
is needed
        23.03
        22.85
        23.04

So with -O2 we still get slightly lower score than clang with -O3 we are
slightly better. push_back inlining does not seem to be a problem (as tested by
increasing limits) so perhaps more agressive unrolling/vectorization settings
clang has at -O2.

I think upstream jpegxl should use -O3 or -Ofast instead of -O2.  It is quite
typical kind of task that benefits from large optimization levels.

I filled in https://github.com/libjxl/libjxl/issues/2970